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Ratt aera | sea aeasie t Varisaqetampbennns oneg Aegan ee kel st nas ie a ai a a ee a aa hy! ashes oat CROPS raga tie mem og credit y te if Pete ‘ : : . te ee Ranine € eee ate 8 Se Resa 18 (Cte x ues diay Pe eis itsibe REGU tA ADH aged Bebb 5 Peewee shoe pad trey ets Han rds raat, UL Si Rom Mem woe CM ale bain 27 toe oor ae & Peon 7 FH ok Ta@apacyinty ety CEE Con RO ee atte a PR eas CLS Bee . ‘ ate by hoe berg ary eg , ererere tre Sonne Rae ee eC RS rez 9 Meat sing AY! Rea Peete ciate acta A : ax aes Ty g*esitw tok are) my Mptety ni tighosse eae eee Nak tee bees GPCR TE EC tA mL Tn Thee Meret Tren Pre ' ‘ en eh ci eae eC Mer eh aren hed Ug, | Hee itt Ataneh “eas\ee Mie gabe cebe a aek ' ' , ’ ‘ . - a6 recy . - Theme Meee ce oe DAYS F Me Meaty ae! wey oe “i Tee gee” patees : ben Eig wah e RIM HT Te nee te on 7 ete ee are re nae tac Arey kak Tea teh eucNats gene ; , 3% + Tene fear a aby Orr ne Vat ag to ou Pitas tet thd < fadoh. 14 an ar . . ne 4 | \ ‘ Mi t 4 vat 4 , roa : aigsto ae eS A hai WNanery Peet wok a . . ' . . i. . 9 wtf fia 6 tee hay hen rT. cms Se othe ity a Vee Om hs i py is ins “ . . riot ed Rune Tie ae) Tale den ee Bud eae “heh Salty qe ‘ aes eceea by Vestine Teele Peete Lape . ik . oe gee rhc eee PR bye ’ Pires wreCery . ' Ca er ra eo Pare ee Oe TOMA Ee nae kek terat eran ge tile TM bag tatistade toe % ‘ 4 ' , Rig wera . 7 ’ Ha tee STD tes book I) VEN ER DEAE aged Re Sate De bee he od ye Ne “ipeny ee eeeee UE Ababa Aa OH a uid, VOW ere ccna Rees beh bie ACA w aerla mets dah aah tad! Dee sony as aos Viteten yal Cree aati nk reed He AGFA REE OFT Ril Fe Asie Re tee malbel ae RAL . ‘ igs : ' » : whe ysi'eeeaek Wearaeane deatey Vd em oreo . ” , . , ‘ Fi : Satine Sak - uh \ Yet Ded ot nam ss ery eo? . Pa Sci aa da eat y, 7 wy bdties vey den thats PNT ad ey Rao MED ERA fd 1a a ue : ere eae Ore 10h : n vey ” Cb at hte i. ee eo Pee Pere ee ee | Le ere a a wy REIS wins ' VN OTe ep ese et Agee eVee DALE UT Gis Bohsh eRzernbae a ie an Ca ee eee it) 10 Uae WU day ‘ 7 , f . * ee ae § gta et 2a geal Seca tart ee nehite me aa vhs + oe fo. Gas hart gery eae ree ea SOR ROME a eee PL Wisiieas aaa . a Shaw dia bY p58 ves ane 4 ‘= : are Meebo ae ties Taaga Avan AMle do atign reo : Perea Dt ota bem eh seat re F , et Di Rect beet Breer rec acer ey Brenan even ire , ev tre Fi A WE Nm vere a MM ARR Babe GHG a Me , . . . Vw ER Saath BE NT Da haba gbyit © . hehe ee ee OC ec TL ee a Poe see : : Inetan tain ' ba : cans : : Soins Bala , : ‘ Nene se eamsas be meme Seatagas , ans wap Pau Nr gn Saito by § . : Bate wed fre en thea i were ria » ss FMA nee ® ‘eyes Ne . ve ever Pe Vccraes LTC cTEn te ans ; Cac eats bewe gett NNR neta . 4 e4 : “s, Rene TOV be te : Na Aan via tag Satna Ba ie A teeth be arm he! Me waa ‘ . e aaa) aN tothe BSeug be Nace nl Oe beet Pe Dawe ge itehes hoa S Wale Weds cy Notes thd Sele betra. baaee : A Sap! Bones earl Peed unt Te Pe eee Petry ae ror ee ores tent : ' : fet oer 8 Ps R Nate . met asp Meee ee ran : ; VON crema eee Tibetan te Oe +i Siren tae : wee ree > : ’ : oy ‘ : » corer tet mae . , ae ' ‘ a a) Py NATURAL HISTORY SURVEY me ats ER iS ) ur a? ag | : F ; ca ee Pitts): * | Eee 7! ste peli lad ; + ; i s ; \ zt Pas Ce | a | ' ™ bo ‘eke San 2 ru an ni one) a 7a) (ie ie i) a) = a ae ’ A a 7 6 ILLINOIS NATURAL HISTORY SURVEY SS Bulletin Contents and Index Volume 27 1957-1961 STATE OF ILLINOIS DEPARTMENT OF REGISTRATION AND EDUCATION NATURAL ah SURVEY DIVISION THE LIBRARY QF Ti Urbana, Illinois ; ior ore any me #13 SeATE OF ILLINOIS DEPARTMENT OF REGISTRATION AND EDUCATION heer uURAL HISTORY SURVEY DIVISTON ILLINOIS NATURAL HISTORY SURVEY Bulletin Volume 27 1957-1961 Printed by Authority of the State of Illinois CR BANA, LELIN OLS -” 1 45 As oe 2 (88859—500—3-64) GB 2 CONTENTS We bieLeE. 1—ECOLOGICAL LIFE HASTORY OF THE WARMOUTH (CENTRARCHIDAE). By R. Wetpon Larimore. August, 1957. 83 pp., color PEPELINE LSU aeD PARLE OSA ry Rte tert ce oder ceed oeah eee hare atacand oye seid Meee tore ria Beenie a dene 1-83 Acknowledgments 2, Areas of intensive study 2, Habitat characteristics 6, Food habits 10, Reproduction 30, Growth 49, Parasitism 64, Behavior 66, Economic rela- tions 69, Summary 76, Literature cited 80 ARTICLE 2—A CENTURY OF BIOLOGICAL RESEARCH. By Hartow B. Miiis, Greorce C. Decker, HErBert H. Ross, J. CEpric CARTER, GEORGE W. Bennett, THomas G. Scott, JAMEs S. AyArs, RuTH R. Warrick, and BEs- ste B. Bast. December, 1958. 150 pp., 2 frontis.; 23 illustrations. ........... 85-234 FroM 1853 TO 1958 85, Natural History Society 86, State Laboratory of Natural His- tory 87, State Entomologist 88, Natural History Survey 98, The future 101; Economic Entomo.ocy 104, Early history 104, Practical problems and progress 106, Biological control 120, Value of insect control 123, Emphasis for the future 124; FAUNIsTIC SuR- veys 127, Early background 127, Changing habitats 128, Periods of faunistic activi- ties 128, Research collections 134, Faunistic reports 135, Retrospect and prospect 144; APPLIED BOTANY AND PLANT PATHOLOGY 145, Early activities 146, Recent activities 149, Past and present 160, Unsolved problems 160, Future possibilities 161; AQuaric BioLocy 163, Beginning of aquatic ecology 163, First field laboratory 165, Fishes and plankton 166, The Fishes of Illinois 167, Illinois River plankton 167, Bottom fauna 168, New lines of research 169, Early management attempts 170, Modern management 170, The last twenty years 172, Direction of future studies 177; WILDLIFE RESEARCH 179, Development 179, Organization 181, Research contributions 183, Wildlife man- agement 198, The future 199; PusBLicaTIONS AND PusLic RELATIONS 202, Early publi- cations 203, Publications series 205, Editorial personnel 207, Public relations 208, Editorial policy 208; Liprary 210, The library at Normal 210, The library at Ur- bana 210, Library collections 211, Library personnel 213, Financial support 213; FoRMER TECHNICAL EMPLOYEES 215; LITERATURE CITED 219 ARTICLE 3—LEAD POISONING AS A MORTALITY FACTOR IN WA- TERFOWL POPULATIONS. By Frank C. BELtrosz. May, 1959. 54 pp., ETT EMME Seay MTS a oi wee, Aol aes tet ctey ose ke ny Sees Sega A WE Sone HES Lite, we, Bye: ee LO OS Acknowledgments 236, Lead poisoning die-offs 236, Availability of lead 249, Ingested lead shot in migrating ducks 254, Lead in wild mallards dosed and released 269, Preventing lead poisoning 276, Discussion 279, Summary 283, Literature cited 287 ARTICLE 4—FOOD HABITS OF MIGRATORY DUCKS IN ILLINOIS. By Harry G. ANpeErSON. August, 1959. 56 pp., frontis., 18 figs.............289-344 Acknowledgments 289, Study procedure 290, Foods of various species 292, Plant foods 323, Animal foods 337, Grit 340, Lead shot 342, Summary 343, Literature cited 344 ARTICLE 5.—HOOK-AND-LINE CATCH IN FERTILIZED AND UNFER- TILIZED PONDS. By Donatp F. HANsEN, Georce W. BENNETT, ROBERT J. Wess, and JoHn M. Lewis. August, 1960. 46 pp., frontis., 11 figs........... 345-90 Acknowledgments 345, Experimental ponds and their watersheds 346, Experimental procedures 353, Pond fertilization and plant life 356, Pond fertilization and fishing success 358, Pond fertilization and standing crops 376, Standing crops and fishing suc- cess 380, Field fertilization and fishing success 383, Economics of pond fertilization 385, Anglers’ evaluation of ponds 386, Summary 387, Literature cited 389 ARTICLE 6—SEX RATIOS AND AGE RATIOS IN NORTH AMERICAN DUCKS. By Frank C. BELLRosE, THomas G. Scott, ARTHUR S. HAWKINS, and Jessop B. Low. August, 1961. 84 pp., 2 frontis., 23 figs................0¢ 391-474 Acknowledgments and sources of data 391, Sex ratios 392, Age ratios 430, Summary 468, Literature cited 471 INDEX The index was prepared by the Section of Publications and Public Relations and printed by authority of the State of Illinois, IRS Ch. 127, Par. 58.12. EMENDATIONS Page 15, column 1, line 21 of text matter. For Phyrganeidae substitute Phryganeidae. Page 18, table 9. For Hydrochnellae substitute Hydrachnellae. Page 135, column 2, line 4 from bottom. For Mitchell, substitute Mitchill. Page 215, column 1, line below Apple, James Wilbur. For Entomologist, 1943-1949 substitute Entomologist, 1942-1949. Page 296, table +; page 299, table 7; page 319, table 32; page 338, table 39. For Belastomatidae substitute Belostomatidae. Page 323, column 1, line 7 (boldface head). For Greater Scaup substitute Common Goldeneye. (Corrected in most copies.) Page 326, line 16 from bottom. For Leguminosae substitute Leguminosae. Page 439, column 1, line 21. For as single hens of male-female pairs substitute as single hens or male-female pairs. Page 448, table 55, line 1. For five substitute six. The following paragraph is from a letter dated December 1, 1959, from W. L. McAtee, for many years with the U. S. Department of Agriculture and the U. S. Fish and Wildlife Service. It may serve as a supplement to Volume 27, Article 2, in that it adds to the list of articles on Stephen Alfred Forbes. “Two papers of mine relating to Forbes not mentioned in the bibliography are an obituary (Auk, July 1930, pp. 453-454), in which I say that he founded the modern science of economic ornithology, and some paragraphs from a chapter ‘Economic Ornithology’ in Fifty Years’ Prog- ress of American Ornithology 1883-1933 (A.O.U., Lancaster, Pa., 1933, pp. 111-29), elaborating on that appraisement.” ILLINOIS NATURAL HISTORY SURVEY Bulle ti 171 Printed by Authority of ce the State of Illinois ene de> a Ecological Life History of the Warmouth (Centrarchidae) R. WELDON LARIMORE STATE OF ILLINOIS e WutiaM G. Srratton, Governor DEPARTMENT OF REGISTRATION AND EDUCATION e Vera M. Binks, Director NATURAL HISTORY SURVEY DIVISION e Hartow B. Mus, Chief abba Al EN OCT 2b i954 HISTORY S! ILLINOIS NATURAL HISTORY SURVEY Bulletin i 27, Article 1 cE piume i Printed by Authority of August, 1957 the State of Illinois Ecological Life History of the Warmouth (Centrarchidae) me WEEDON: LARIMORE STATE OF ILLINOIS e Wutt14M G. Stratton, Governor DEPARTMENT OF REGISTRATION AND EDUCATION e Vera M. Binks, Director NATURAL HISTORY SURVEY DIVISION e Hartow B. Mitts, Chief Urbana Illinois STATE OF ILLINOIS Wiruram G. Srratron, Governor DEPARTMENT OF REGISTRATION AND EDUCATION Vera M. Binks, Director BOARD OF NATURAL RESOURCES AND CONSERVATION Vera M. Binks, Chairman; A. E. Emerson, Ph.D., Biology; L. H. Tirrany, Ph.D., Forestry; Waiter H. Newnouse, Ph.D., Geology; Rocer Apams, Ph.D., D.Sc., Chemistry; Roperr H. Anperson, B.S.C.E., Engineering; W. L. Everitt, E.E., Ph.D., Representing the President of the University of Illinois; Detyte W. Morris, Ph.D., Presi- dent of Southern Illinois University NATURAL HISTORY SURVEY DIVISION, Urbana, Illinois SCIENTIFIC AND TECHNICAL STAFF Hariow B. Mitts, Ph.D., Chief Bessie B. East, M.S., Assistant to the Chief Section of Economic Entomology Georce C. Decker, Ph.D., Entomologist and Head J. H. Biccer, M.S., Entomologist L. L. Encuisu, Ph.D., Entomologist S. C. Cuanpier, B.S., Associate Entomologist Wiruis N. Bruce, Ph.D., Associate Entomologist Norman Gannon, Ph.D., Associate Entomologist W. H. Lucxmann, Ph.D., Associate Entomologist Joun D. Briccs, Ph.D., Associate Entomologist Ronatp H. Meyer, M.S., Assistant Entomologist Ropert SNetsiIncER, M.S., Field Assistant Joun P. Kramer, M.S., Laboratory Assistant Eucene M. Bravi, M.S., Research Assistant Ricuarp B. Dysart, B.S., Technical Assistant Apert Saraxo, B.S., Technical Assistant Eart StapEvuacHeER, B.S., Technical Assistant Suz E. Watkins, Technical Assistant H. B. Perry, Ph.D., Extension Specialist in Entomology* Stevenson Moore, III, Ph.D., Extension Specialist in Entomology* H. B. Cunnincuam, M.S., Research Associate* Joun W. Marrteson, M.S., Research Associate* Crarence E. Wuirte, B.S., Research Assistant* Joun Artruur Lowe, B.S., Research Assistant* Cuartes Le Sar, B.S., Research Assistant* Loutse Zincrone, B.S., Research Assistant* Mary E. Mann, R.N., Research Assistant* Section of Faunistic Surveys and Insect Identification H. H. Ross, Ph.D., Systematic Entomologist and Head Mitton W. Sanperson, Ph.D., Taxonomist Lewis J. Srannarp, Jr., Ph.D., Associate Taxonomist Puiurre W. Smiru, Ph.D., Associate Taxonomist Leonora K. Guioyp, M.S., Assistant Taxonomist R. B. Sevanper, Ph.D., Assistant Taxonomist Epwarp L. Mocxrorp, M.S., Technical Assistant Tueitma H. Overstreet, Technical Assistant Section of Aquatic Biology Georce W. Bennett, Ph.D., Aquatic Biologist and Head Wiruiam C. Starrett, Ph.D., Aquatic Biologist R. W. Larimore, Ph.D., Associate Aquatic Biologist Davin H. Buck, Ph.D., Associate Aquatic Biologist Rosert C. Hittipran, Ph.D., Associate Biochemist Donatp F. Hansen, Ph.D., Assistant Aquatic Biologist Joun C. Cratrey, B.S., Field Assistant Crarence O. Stevenson, B.S., Field Assistant Rosert D. Crompton, Field Assistant Section of Aquatic Biology—continued Maurice A. Wuiracre, M.A., Assistant Aquatic Biologist* Witu1am F. Cuivpers, M.S., Technical Assistant* Arnotp W. Frirz, B.S., Field Assistant* Ricuarp E. Bass, Field Assistant* Pau Frey, B.S., Laboratory Assistant* Section of Applied Botany and Plant Pathology J. Cepric Carter, Ph.D., Plant Pathologist and Head J. L. Forsserc, Ph.D., Plant Pathologist G. H. Borwe, M.S., Associate Botanist Rosert A. Evers, Ph.D., Associate Botanist R. J. Campana, Ph.D., Associate Plant Pathologist Joun M. Ferris, Ph.D., Assistant Plant Pathologist Rosert Dan NeeEty, Ph.D., Assistant Plant Pathologist E. B. Himenricx, M.S., Assistant Plant Pathologist Rovenia F. Firz-Gerarp, B.A., Technical Assistant James D. Birsrucx, M.S., Research Assistant* Section of Wildlife Research T. G. Scott, Ph.D., Game Specialist and Head Rateu E. Yeartter, Ph.D., Game Specialist Cart O. Monr, Ph.D., Game Specialist F. C. Be.irose, B.S., Game Specialist Ricuarp R. Graser, Ph.D., Associate Wildlife Specialist W. R. Hanson, Ph.D., Assistant Game Specialist H. C. Hanson, M.S., Assistant Game Specialist Frances D. Rossins, B.A., Technical Assistant Vircinta A. Lancpon, Technical Assistant Howarp Crum, Jr., Field Assistant Jack A. Exuis, M.S., Field Assistant* Ronatp Lasisxy, M.S., Field Assistant* Rexrorp D. Lorp, D.Sc., Project Leader* FrepERIcK GREELEY, Ph.D., Project Leader* Guen C. Sanpverson, M.A., Project Leader* Paut A. Vous, Jr., B.S., Project Leader* Section of Publications and Public Relations James S. Ayars, B.S., Technical Editor and Head BiancHe P. Younc, B.A., Assistant Technical Editor Wiiuram E. Crark, Assistant Technical Photographer Witiiram D. Woon, B:S., Technical Assistant Technical Library Rut R. Warrick, B.S., B.S.L.S., Technical Librarian Net Mites, M.S., B.S.L.S., Assistant Technical Librarian CONSULTANTS: Herretorocy, Hosart M. Smirn, Ph.D., Associate Professor of Zoology, University of Illinois; Parasirotocy, Norman D. Levine, Ph.D., Professor of Veterinary Parasitology and of Veterinary Research, University of Illinois; Witp.tire Researcu, Wiitarp D. Kuimstra, Ph.D., Associate Professor of Zoology and Director of Co-operative Wildlife Research, Southern Illinois University. *Employed on co-operative projects with one of several agencies: Illinois Agricultura] Extension Service, Illinois Department of Conservation, United States Army Surgeon General’s Office, United States Department of Agriculture, United States Fish and Wildlife Service, United States Public Health Service, and others. This paper is a contribution from the Section of Aquatic Biology. (56723—5,500—5-57) cn eae 2 CONTENTS MIAME EI OET LGN (Saya tpn c eek es Secs, GS eA erat ty we sa Bd Mere Bey ke ae stn 2 SIN TEN SLY Be OE UD Yo 2 ac» accra blac abin-s guehind’s lie’ o icon ce teal e ns Boa bode 2 Fae RA RMMECASTA (Tes crete ie. Gite lee aco uae wax cy seed ithe Oe ae ELS eck Milles 5 ieee! Oy ae? 4 earn me beet bee crevasse th areas eA PS eae DEI Ee ee SOR not AEM a Eee SS 5 Meera GEMS EE SICA CT ER ES TICS cs chu tie cial ais is-e GD bow kan Scigs FA Sawa ie aio cae ao cinee ta s 6 PeEarE ON Mand sOttOnl: VUAtETIAlS) 3 .cMae bi: % Gas fe decsteoma cars ain, sem a bec cate 6 REET Cae cerca ainh See Ate: auaveee oe shank Gites Bisrects Sime aM ver GS Wenn Conteh A ne eA 7 asap RNs at cra et eran nano esd BA ord Dre tr Nan eval tac te ee ee aN 8 erie Orer Cen were eet crate ge cote ate Cis a cia eee etd Sak oe eh ed ee 2 ence PTOULETIER Ai Olen ote cate tN ot Re fy as ee) ne es Vil ae 10 aM TREE MEN IS er GOS esky ess Rachel 2 fo,cvallahe hie carte russe athe ls Pe us. Geahensimodls De ata weenie a nS: 10 ELBIT \DCUSS "Ge whet UIC eR eR ey a ae oe es lb CR ee 10 Me A OOds: ily Lk WOdl ADIEAES et fe a js 45/4, oe eck oe ela dane Ae 14 Feta gtr ac) Pee he, oPesevoie «caer ds otal 2 1d a Soke ews Cid Noa ns ovis Mee el eee 14 Reena ieme le RCIA tol tre Sia NR a chew tn ahs Cia untd shah a Se BVA es ic Oe EE 15 pee PN IMMUN Tee TAS 8 ee Me oh ehsci w Yo alsin or gate «ae eh Orava HL Aa vet Ry WS ahh eh ERAS TE res, 20 RN REN EC Mee ee gh e cc Rae Vidz st Tena casera So ose ht ca ho, ae ueleale Saar tate, elas rans av ae Ree 21 ral Pm NIMES acre Vege: Shae cold Ge aide vigrameneen fsa ts Soong aula epee 22 SEN CRUST 0? pc RO em AN Rae NN Pe ER aes eo a DR Sag eh Ra Ye So 23 IB EAN a Scab inlh dulce tone MaN Petts nt RCE De a ee VST ae PLO yea PUR th eR LSS, 23 [tele ol CATE TOT ETON Ds is Sars ete 0 cence a aera pra ee OR ON ha ada 26 Maree RCRD S PASTA ia ki utc Ach: t's Wacko Naess ew sis ana C4 Elie abe peat ae Me 27 EES CMTC ORS OMINSE CLELOIN oslo: cht, ie sat wid, Neg ROU letas op scecshe, whia'y see DANE aR a 28 Bracna oe onelnstons omeHood: habits. «cc sce sae es 34 6k ope aeind ws cothareeereme 29 ERECT) CHT Aah ae NO CE Sas, SR A te PP on at ge PR RO MR 5 BOE ie 30 Arena it we tene me E MOGUELS etc. 5, ciskaca (ee an os See eh tet raw oe ae Ses oe Ree 31 MCE erie Aa ey Clem natn i shite ee te act led aie Ubsceys a laivedva Svat eeaede ieee 31 LPR aT aaa eg ga ely 20 ce gee et RAV nOe, Aare ee) Rae ge EP OEY FO te NP 30 Se Tea reve mene 1OP MONA ws. die ats at ees Sateen sce vcpahe wed alabama thane aed Lae ee 39 emiestl cages ume COLVICLES covncta Nc waa Hace tes MOC ate a ctvarels oooh G. arseniere wane & OE Haak aces Uetiees 39 acarionrandy OAnSeCuerionr Or INESES.c.5 5 csi os wets oe sees Sead ch sally be Mae 39 Reece MINTY SOUT SIND aya cel sitet.) < oie is salle svne coun oles oR eho Cetin Mint Fae eerie a Peo ee cage ie eh TAU Rp nda oe Seles =a Stra eld Gh es. aon Do alee dee 43 mizesane: Ace rat OExuall IWlatunity./: 2... Joe ass cc aoee eid «Deedee vedios laces 43 Petes Bie etme ST Sei Thee ee Ne sight le rtte sh iy dc vas wishin Svlaids Soom «oe aman eo le 43 Weposition-and-Mertilizationcat Bees, .iik osc od us dase e eee ba luslew en hewns 43 elise hiay ay Heel CUA OS CAA del Le ee a) scrawl 1h Aloe 4 Sirs, e-h wl Siw cess teh ose alal a abaiubane hats 45 Wevelopmernt tos. MamlryOs ices Pee ie Pee Aes 4 se ale sce ahicta be wre Cac BAe oh alae 45 Development and-Growetl Of Larvae... ibs. -s eke eae bees eeee ssh weveeas 47 ISEB BOP To Ml WS ce Tole Cs a oe PR A See: SR OME i ae 48 AEROS) MANLECEIE IDE VAY ANS acs Aimee ste ety wets dle Ae aurdpie, no alee Pec Mee wus 49 CHELLIS Gg RRS i ERDAS OE PNT cea Iv ee a Ae es US a DR 49 Pee enuIncre GrrUwibie rte pre. hte AA tac nate Pid aah so wn MM aM ed bee 49 elation: Orjboay-Growtl £0 ocaleMGrowth: f/ceg 2 ienaak ded aca hs kano a eons 49 Relatiomot Bady Growemto ) ail (Growth)..: 5 256s oon toe 0h so caoalea < 50 Relation of Growth in Length to Growth in Weight..................... 50 Se rciem bette Oita Liierner: tat eeers gk chedahs re. Saleen alate as bgeeele Ga lbe oles Reba 51 Beale Micthod wt Calenlating Grow flies. os ccpe c.. cdie sce ole saath wite wavs ele were 52 Walidiiy ot stherAmmnulustasea= Wear Vath. c...6s 0s ness ob ame me gelatin alana. 52 Chamevensticsnon ation A mmulis..6 tae eo tk. S40 ais Set cin no os mee Sea nae ee ee 53 Meine car a MMS OUIPIEHION ts, pci faiaid cee sce-sloGon eels e « 2G ae cea pede bes 54 LEG CTeTATAI MIDI ES Gobir Sch y O99 OO nn eS RO ea ee 54 Growth In Park: Pond... si oo. cic Sie cos eke ce cteciell er one 5 im tin anata 55 Collection and Preparation of ‘Materials... ...'. 0... 2... 6.2.0. eee 55 Growth Differences Between Sexes...... 80.0050 s. 003 os vs ee 56 History of Successive Year Classes. . 0.020.) nese e os tise 56 Fluctuations in: Annual Growth: .!<. 005 /60).00 06 ea esa oe 58 Seasonal Growth. foo. i6.o. heel a. eee . Ta 59 Growth in Localized Population... ::.2. 2... 5...2:.:.+./ 272 eee 60 Compensatory “Growth...........0 0.00 4200420000. Aes es oe 60 Sizes and Longevity << . iso. 0.5. -0 264. Janae eS. 0 te er 62 Growth in Venard Dake: :... 05. ..000 ce cn ete howe we wane 62 Growth in Other Water Areas..........-...----- viva: bn bide re 62 PARASTTISNE 2 ce Coir tee a Oia Le La EOE lai Ss Pale ee 64 PERTLAVIOR oa ba voc his Toa ee eR a ns LL Dek ee weg en eS Sere err 66 General Activity and Disposition. <1... 000.00 00. oe aa Si er 66 Reproductive Behavior.:.....2..... 56S e. 0% 0) ie ee 66 Defense of the Nest Area.../.... 0205100. .aee be hcl eo 66 Synchronization: ¢:. 2.4.4.5. 2... s ste bee b ews bel Gk oo eee 67 Orientation vc 562 bo ek ee seb bc oe oooh ie wens tee ee ee 67 Persmasion vies cede 2c bales dius enebantndsage ses eee 67 The spawnmp Actes). 6.2 eo ee ee eee 67 Reproductive Isolation......5...).00..5.c)ea bees oe 2s) er 67 Parental Cate: 6450 cect. 6. oaks oSabed: bo oa eee eee 67 Group’ Behavior’ 2... 655 ted cies hp 0 eS ee a ae oe 68 AGPTERATIONS. cs 226 oes be ts 248 hee ylelas oi eyed Ons oie Oar 68 Phierarenye. fo oee foes le bo has, eaa)s Rob ote ee ee 68 Feeding *Behaviot si... 622 285 Se OG en dle eo Palle wis ino bo ae 68 MAT TUG bs oo is ax oreo xen ee ce Ae wi eed S hetag ahd Stam aheaid ee Ce er 68 BPeonomic. RELATIONS. 2.02505. SoG. Peon ae Bree ee le Pe 69 The Warmouth ‘as:a. Food: Fish. . o.oo. 0 ede oe eee eee 69 ‘The Warmouth as a Sport, Fish... . 022042005. .2025.%. 36 os a 69 ‘The Warmouth as a Laboratory Fish.....4... 2022005 22..22 425 see 71 The Warmouth in Artificially Established Populations........................ 71 Experimental Species: Combinations.:.....2..2. 66.0. .805 settee oe 72 General Conclusions About Species Combinations.............-.-..++--++- 76 SAT MART ARY Seg ics Fu carota Saeed & Side Ski e 4A] AR Saree the Dolce et oe ee 76 LITERATURE: (CITED A. 3 ees ee oe hn hee eed oe eee 80 os Ss es > SI f= eS WARMOUTH Maynard Reece Ecological Life History of the Warmouth (Centrarchidae) VERPOPULATION among cer- () warm-water fishes is now com- monly recognized as a cause of poor fishing in many lakes and ponds of the United States. More than a decade ago, Bennett (1944:186) suggested that perhaps some sunfish not prone to overpop- ulation would, with little control by man, produce good fishing over a prolonged pe- riod. This suggestion stimulated a search for a species that has a low reproductive potential, a species that does not tend to overcrowd its habitat, and yet has good sporting qualities. The warmouth, Chaeno- bryttus gulosus (Cuvier), appeared to be such a species. The study of its life history and ecology presented here may serve as a basis for an estimate of the potential value of the species as a companion for bass or other game fishes in lakes and ponds of [Ili- nois and neighboring states. The warmouth is a dark, thick-bodied sunfish (family Centrarchidae) which su- perficially resembles the somewhat bet- ter known rock bass, 4 mbloplites rupestris (Rafinesque). It is readily distinguished from the latter by the presence of three spines in the anal fin; the rock bass has six. A good color and morphometric description of the warmouth is given by Forbes & Richardson (1920: 245). The nomenclature of this robust sunfish was summarized by Jordan, Evermann, & Clark (1930:302-3), in whose check-list Chaenobryttus gulosus was the accepted name. Harper (1942:50) pointed out that Bartram in his Travels, 1791, had accu- rately described this species and called it Cyprinus coronarius, a name which ante- dates Chaenobryttus gulosus by 38 years. Recently, however, the Committee on No- menclature of the American Society of Ichthyologists and Herpetologists agreed that, because Bartram was not consistently binomial in the work cited by Harper, the name Chaenobryttus gulosus should be re- applied (Bailey 1956: 336). Of the 16 R. WELDON _ LARTMOR-:E or more common names given to the spe- cies, warmouth, warmouth bass, and gog- gle-eye are the most widely known. The American Fisheries Society Committee on Common and Scientific Names of Fishes (1948:16) designates this fish the war- mouth, the name used throughout this paper. The warmouth occurs generally in suit- able waters throughout the central and eastern United States and south to the Gulf Coast. Its distribution extends from Kansas and Iowa to the Mississippi River drainage in southern Wisconsin, includes the southern two-thirds of the Lower Pen- insula of Michigan, Lake Erie, and the Allegheny River tributaries of Pennsyl- vania, and embraces the territory south- ward to Florida and west through the Gulf states to the Rio Grande (Hubbs & Lagler 1947:93). As a result of intro- ductions, it is now found west of the Rocky Mountains. Introductions into Cali- fornia, Washington, and Idaho were made as early as the end of the last century (Smith 1896: 441). In Illinois, the warmouth has a wide, scattered distribution. Approximately a half century ago, Forbes & Richardson (1920: 246) found it in glacial lakes of northeastern I[|linois and showed that it in- creased in abundance from north to south; they gave it frequency ratios in their col- lections for northern, central, and south- ern sections of the state as 0.44, 0.78, and 1.78, respectively. Leonard Durham, while employed by the Illinois Department of Conservation in 1950-1955, found a somewhat different pattern of warmouth distribution (unpub- lished data). In studying representative populations of fish in 426 Illinois ponds and lakes, some of them natural and some artificial impoundments, Durham found little difference in the frequency of occur- rence of warmouths in the three zones of the state then recognized by the Depart- C1] 2 Ittinors NATURAL HIsTory Survey BULLETIN ment of Conservation. In the northern, central, and southern zones, warmouths were taken from 15.4, 17.1, and 15.4 per cent, respectively, of the waters sampled. These figures suggest that the distribution of warmouths in Illinois may have changed since Forbes and Richardson made their collections. The construction of many arti- ficial impoundments requiring the wide- spread transportation of fishes for stocking purposes probably is responsible for some of the changes that have occurred in the distribution of this species. Although principally a pond and lake fish, the warmouth occurs in the Rock, Mississippi, and Illinois rivers and is re- ported as common in small, sluggish streams of the southern part of the state. Its scattered distribution in Illinois coin- cides with the occurrence of suitable habi- tat. ACKNOWLEDGMENTS The research upon which this paper is based was a project of the Illinois Nat- ural History Survey and was proposed and supervised by Dr. George W. Bennett, who gave guidance and help in all stages of the work. Much of the material presented here was included in a thesis submitted in partial fulfillment of the requirements for the degree of Doctor of Philosophy in the Horace H. Rackham School of Graduate Studies of the University of Michigan, 1950. As chairman of my doctoral com- mittee there in the Department of Zool- ogy, Dr. Karl F. Lagler directed my graduate studies, made many suggestions for my research, and helped me revise my thesis manuscript. The paper published here was edited by Mr. James S. Ayars, the Natural History Survey’s Technical Editor. His skill and patience have added considerably to the accuracy and clarity of reasoning, expres- sion, and composition. Mrs. Darlene Ose, while secretary in the Section of Aquatic Biology, read and criticized the manu- script. Dr. Leonard Durham, while employed by the Illinois Natural History Survey from April, 1947, to August, 1950, as- sisted in all of the field work and in many of the laboratory preparations; his con- Vol. 27, Art. 1 tinued interest added greatly to the com- pleteness of this study and to the pleasure of conducting it. Mr. W. Leslie Burger, also while employed by the Natural His- tory Survey, helped sort the contents of warmouth stomachs, after which members of the Section of Faunistic Surveys and Insect Identification of the Natural His- tory Survey identified many of the inverte- brate food items. Messrs. William J. Harth, James F. Opsahl, and William F. Childers, while with the Department of Conservation, assisted in some of the field work or in the tabulation of data. Other members of the Survey staff and my wife, Glenn E. Larimore, gave willing aid to the work. I appreciate the permission to refer to unpublished observations by members of the Natural History Survey staff on war- mouths in Illinois; observations of special value are those by Dr. Bennett at Ridge Lake, in Coles County, and at the Polly- wog Association water area, in Vermilion County, and those by Dr. Donald F. Han- sen at Lake Glendale, in Pope County. Credit for these and other unpublished ob- servations is given in the text of this paper. The Associated Tackle Manufacturers supplied certain equipment necessary for field work and gave financial support for my library studies at the University of Michigan. The owners of several Illinois ponds in which warmouths were studied aided this investigation through their willing co-op- eration. The picture of the warmouth repro- duced as the frontispiece was painted by Mr. Maynard Reece and is used here through the courtesy of the Iowa State Conservation Commission. AREAS OF INTENSIVE STUDY As part of the investigation reported here, intensive studies of warmouths were conducted in two aquatic habitats, Park Pond and Venard Lake, figs. 1 and 2; these studies were then compared with more general observations on warmouths in other waters. Both of the aquatic habitats in which the intensive studies were conducted were man-made: a flooded stripmine area and a small artificial lake. The many differ- August, 1957 LarimoreE: Lire History oF THE WARMOUTH 3 Fig. 1—Southwest section of Park Pond, Vermilion County. Fig. 2.—Part of Venard Lake (principally the east arm), McLean County. ences between these two water areas per- mitted an evaluation of the effects of a con- siderable range of habitat conditions on warmouth populations. Park Pond Park Pond: has a history that dates back many years. More than a quarter century ago, in Vermilion County, in east-central Illinois, an abandoned stripmine flooded with waters from the Salt Fork River was ILLinois NATURAL History SuRVEY BULLETIN Vol. 27, Art. 1 water level was raised by the two small dams, lined the water’s edge. The chemical composition of the water differed from that of many other Illinois lakes, primarily in its high mineral content, table 1. Sulfates were especially high in concentration, but the buffer effect of other substances eliminated the extreme acidity often associated with the sulfur of mine waters. The fish fauna of Park Pond had been derived from two sources. Many species Table 1—Chemical composition (parts per million) of water from Duck Pond, in the Polly- wog Association area, Vermilion County, Illinois, and from five recently constructed United States Soil Conservation Service ponds in central Illinois. Iron MerTHYL ine : Na ORANGE Ponp Fil- | Unfil- Ca Mg and K SO, NO, Cl ALKA- Harp- tered | tered LINITY NESS Duck Pond Joly: 05, 193822556 OLD] TAB’ 38.22) 4872 236701; 9.0) eae0 152.0 343.5 Duck Pond October 7, 1942.... 0.1 | 58.8 | 44.6 3.5 | 33.0 146.0 329.0 Five Soil Conserva- tion Service ponds (average) August- September, 1939...| 1.1 2.78) 26.9 | 15.1 TG e2. 2.0] 2.8 130.8 127.1 leased by a group of sportsmen and con- servationists, who, in about 1929, had formed the Waste Land Reclamation As- sociation. In 1932, this area was acquired by a group of sportsmen who had formed the Pollywog Association, an organization that has continued since that time to use the area for hunting and fishing. A few years after the formation of the Pollywog Association, the construction of two small dams raised the water level several feet. A major part of the investigation reported here was based on material from Park Pond, which in 1946 had an area of 18 acres, in the central part of the Pollywog Association area. When field work for the warmouth study was begun in 1946, the old mining cuts from which coal had been taken in 1889 and 1890 had become filled with water and appeared as irregular lakes con- nected by many narrow channels, fig. 1. High banks, formed when soil was re- moved to expose underlying coal beds, had become covered with dense brush and small trees. Older trees, killed when the of fish had entered on flood waters from the nearby Salt Fork River. Fish of some of these species, as well as others not in- digenous to the Salt Fork, had been placed in the pond by the Illinois Department of Conservation. Thirty-six species were re- corded from this pond, table 2. The relative abundance of these species was disclosed by the poisoning of the fish populations in four ponds of the Pollywog Association; each of these ponds was iso- lated from other waters except during floods. The total area to which poison was applied equaled 9.07 acres and was sup- porting a fish population which averaged 455.5 pounds per acre. Gizzard shad, carp, and bluegills comprised high percentages of the total weight of all fish collected from these four ponds, table 3. War- mouths represented 1.1, 0.9, 1.5, and 10.4 per cent of the weight in the four areas, or 1.6 per cent of the combined weight of fish from these waters. They made up a greater proportion of the weight of the fish population in these waters of the Pollywog Association than in most other Illinois August, 1957 Table 2.—List of fishes collected from Park mation on the relative abundance of each kind.* Larimore: Lire History oF THE WARMOUTH 5 Pond of the Pollywog Association, with infor- SPECIES RELATIVE ABUNDANCE Peazardanad. Derosoma cepedianum (ie Sueuf): 02. cscs. ee ae De ve be beeen Mn lerckceatpsucker,Carpiodes Cyprinus (Ise Sueur). «sc. csi ou eee cae eee ee hn ape MimtemuckerGatostomus commersont (acepede).. cok ee es ot ee ee ce be cede aceabdatns eeemmncnCKer Mit yzon sucéiia (liaCepede).wh, o. 6... keeles be ce be ele ose bere tess alee Spotted sucker, Menvirema melanops (Ratinesque).... 0.2.02. ..-5-6+. 0.0: eect esa veceass Piiversedhotse, Moxostoma anisurum.(Ratinesque).:. 20.3.5. 000600 2 ee cc a cn ees Northern redhorse, Moxostoma aureolum (We Sueur)... 202 debs ee vs dn eh Lele eee Carp, Cyprinus carpio Linnaeus. . Bluntnose minnow, Pimephales notatus Ee se hehe ee OT Pe ae Fathead minnow, Pimephales promelas Rafinesque. . Golden shiner, Notemigonus crysoleucas (Mitchill).. . CS Cay nr am canrt gee ae ahd Pdeueicatisn, (ofaiurws. punciains (RARMESQUE) oc. gos we oye nt bc pce ec doe cele me Yellow bullhead, [ctalurus natalis De ae oats oie Spare rita: Black bullhead, /ctalurus melas (Rafinesque) . Flathead catfish, Pylodictis olivaris (Rafinesque).. PUA NO at A Ee Rtn GO Madtom, Noturus sp.. Grass pickerel, Esox vermiculatus Le Sueur. . American eel, Anguilla rostrata (Le Sueur)... ... Banded killifish, Fundulus diaphanus (Le Sueur). Blackstripe topminnow, Fundulus notatus (Rafinesque) . Se Bae ad sees Yellow bass, Roccus mississippiensis (Jordan & Eigenmann). See tity Rt aE Be Yellow perch, Perca flavescens (Mitchill) Mere Pcriia caprodes (Ratiesque) 0+. 7.2.6 a cone ced snensiuspocees..4luserens Johnny darter, Etheostoma nigrum Rafinesque. .. . Smallmouth: bass, Micropierus, dolomtent Lacépéde...: 0.0.0 soe cc ve vee es epotted Dass, Micropterus punctulatus (Rafinesque)....2. 004.0... 5... 2 eee ee ees iearpemouth bass Mzcroprerus salmoiaes (hacépede).: .. 4.2252... 2 cso es sae es Mrmontuere nurnorryitns- eulosus (Cuvier)... s\ 0h .4 os. dee ce ook ce we hs eee Pereccolsuniichs /epom1s cyancius, Rafnesque. ox 0.05.5 6.0.20 s 2 eben ev eve ilec es En picinsecd. Lepomis e1brosus (LADNACUS) we vec ee es Feb es one on ws Bluegill, Lepomis macrochirus Rafinesque. .... Orangespotted sunfish, Lepomis humilis (Girard). Longear sunfish, Lepomis meg tlotis (Rafinesque). . White crappie, Pomoxis annularis (RamMeESCUee eee a ee ane SAS ORE yee Bieckerappie... umoxts maromaculatus (Ie Sueur): ict... de ee Seg ee be hw el Brook silverside, Labidesthes sicculus (Cope)................ _. Abundant .Common .Common _Rare ~Common ..Rare .Common .. Abundant _Rare _.Rare Common -Common Abundant ..Common .. Rare ; .. Rare ..Common ..Rare _...Common _. Abundant ..Common _. Rare _Rare ... Rare _. Rare : ..Rare ...Common ...Common .. Common _...Common _. Abundant _...Common _.. Abundant _. Abundant .Common ..Common *The common names used here and elsewhere in this paper follow those of the American Fisheries Society Special Publication Number 1, names are those given by Bailey 1956. waters from which fish collections have been taken in recent years. Venard Lake Little is known of the early history of Venard Lake, fig. 2, an “‘old” artificial im- poundment 1 mile south of Bloomington, near the junction of state highway 51 and United States highway 66, in Mc- Lean County, Illinois. In 1947, the lake had an area of 3.2 acres. Though there was a small spring at the upper end of the lake, most of the water came from surface run- off flowing into the lake from two shallow valleys. Settling basins, built in both of these valleys above the lake, removed much of the silt load carried by surface water; 1948, or the changes recommended by the Society (Bailey 1952, LOSS most of the scientific even so, during a period of several decades, the basin had accumulated much silt. In 1946, the lake was drained, a stunted fish population removed, and the basin allowed to refill with water. In April of 1947, Venard Lake was stocked with the follow- ing fishes: 225 yearling largemouth bass between 4 and 8 inches in total length, 15 largemouth bass between 9.6 and 13.7 (average 11.9) inches in total length, and 101 warmouths between 5.1 and 8.1 (aver- age 6.8) inches in total length. Extremely large broods of both bass and warmouths were spawned in 1947. The fish placed in the lake early in 1947 grew well and supported excellent fishing the following months. Many warmouths of the 1947 year class were caught in spring 6 Ittrno1is NaTuRAL History SurRvEY BULLETIN Table 3.—Kinds of fish that were collected from four Pollywog Association water areas treated with rotenone and the percentage of the total weight of fish comprised by each kind. The total area of water treated was 9.07 acres and the average standing crop of fish was 455 pounds per acre.* Per CENT OF Kinp or FisH ToraL WEIGHT Largemouth bass........ White crappie... 20... . - BelGep Tibet om as eons e =o Warwiguthr iat ee: Othertine fish... 15 = 2, RB ALAS rcs ees eet, (Coatseish: occ cca Le Gizzard:shads.!.. 22.532 Other forage fish......... _ erm KHWMnDOOD ON Ss SCONCE WW S IMG] TH einen? Pint 8 AE SOP She ~ S *Data from three of the water areas were collected by Dr. George W. Bennett. Data from the fourth, Park Pond, were collected by the author. fishing of 1949, but very few were taken in the summer of that year. Most of the bass caught in 1949 were of the 1947 year class; many of them were still below the then legal size of 10 inches. During several weeks in August of 1948, shallow parts of the lake were dredged. This operation killed many of the 1948 brood of warmouths, in particu- lar those trapped in the large weed masses removed from the lake. The bass, on the other hand, were apparently unharmed. HABITAT CHARACTERISTICS Collections of the warmouth from many lakes, ponds, and streams of Illinois, and descriptions of the water areas in which this sunfish is found in other parts of its range, indicate that it is usually associated with certain habitat characteristics. Vegetation and Bottom Materials Dense weed beds and a soft bottom are two habitat characteristics with which the warmouth is usually associated. Brush and roots attract this sunfish, and in water areas lacking extensive weed beds, as in some of the bottomland lakes of the South, old tree stumps constitute the common hid- ing places of the warmouth (thus, the name “‘stump-knocker” is sometimes given Vol. 27, Art. 1 to it). The quiet, almost sulky disposi- tion of the warmouth and the customary association of this fish (particularly young and moderate-sized individuals) with pro- tected hiding places cause members of this species to concentrate in weedy and stump- filled waters. In the Everglades region of southern Florida, Bangham (1939:263—-5) found warmouths second in abundance to gars. The waters were slow moving or still, dark-colored, usually choked with vegeta- tion, and with bottoms composed of soft muck. Of five ponds in the Ocala National Forest in Florida censused by Meehean (1942), all contained warmouths, table 4. The population having the greatest concen- tration of warmouths was in an old pond (Little Steep Pond) with a thick layer of humus on the bottom and a mat of veg- etation covering the entire surface. When Tarzwell (1942) applied poison to three backwater sloughs of Wheeler Reservoir in Alabama, he found warmouths in all populations, although in low percentages by weight; the highest proportion of these fish by weight (1.0 per cent) was asso- ciated with a soft silt or mud bottom, table 4. The greatest proportion of warmouths that Bennett (1943:360) encountered in censusing 22 ponds and lakes of Illinois was in Delta Pond (10.7 per cent war- mouths by weight), table 4. As only 2 years had passed since this pond had been stocked with game fish and pan fish, the fish population probably ‘did not reflect the environment of the pond as much as it did the original stocking. Onized Lake, which contained the second greatest proportion of warmouths (6.5 per cent) that Bennett found in a population, was an old pond with heavy marginal vegetation that fa- vored these fish. Warmouths in Onized Lake may have been favored also by ex- tremely heavy and selective fishing that had resulted in the removal of large num- ‘bers of fish of other species. The fish population in four shallow, mud-bottomed backwater areas of the Mis- sissippi River contained low percentages of warmouths (Upper Mississippi River Conservation Committee 1947:25—7 and 1948 :23-4). Two of the areas, near Sa- vanna, Illinois, contained respectively 0.3 per cent and 1.0 per cent warmouths by August, 1957 weight. The two other areas, near Oquawka, Illinois, contained respectively 0.2 per cent and 1.4 per cent warmouths by weight, table 4. Turbidity Forbes & Richardson (1920: 246) con- cluded that the waters in which they found the warmouth in their II]linois collections indicated for this fish ‘‘a deliberate prefer- ence for muddy water over pure.” Cer- tainly the warmouth, now as in the time of Forbes and Richardson, is found more frequently and in greater abundance in muddy or turbid waters, usually charac- teristic of lowland lakes, backwater areas, Table 4.—Data from fish censuses of 29 water areas containing warmouths: Larimore: Lire History oF THE WARMOUTH 7 and sluggish streams, than in less turbid waters. However, the occurrence or abundance of the warmouth in turbid waters may not indicate a direct preference of this fish for these waters. Rather, it may show that the warmouth has a greater tolerance of turbid waters and conditions associated with tur- bidity than have most other sunfishes. This tolerance may give the warmouth certain advantages in a population in which it must compete with many species and may account for its frequently comprising greater proportions of the total fish popu- lation in turbid waters than in clear. Turbidity may affect growth rate of and fishing success for the warmouth. The for each area the approximate weight per acre of the standing crop of fish and the percentage of the total weight comprised by warmouths. < ae 48 & g |esee| 2os SA lees | See Bopy or WaTER ea zEus Peleg Source or Dara << Bo an & Bes bey ne, tw ms es Rage = Ww 5 P ee a Little Steep Pond ene 2.10 105 10.55 |Meehean 1942 First Pond (Florida). . 7.00 110 0.99 Big Prairie Lake (Florida). . 4.00 61 1.87 Buck Pond (Florida). . 18.00 33 6.61 Clearwater Lake (Florida). . 24.00 22 0.82 Upper Railroad Pond (Alabama). . 6.50 292 0.07 |Tarzwell 1942 Powerline Slough (Alabama). . 1.10 831 0.07 Sweetwater Slough (Alabama)... .. ol ah eae 4.40 188 1.00 Southside Country Club Lake :(Illincis). Sek aeoed 8.40 719 tr. Bennett 1943 Homewood Lake (Illinois). . ; 2.83 699 tr Fork Lake (Illinois). . Me eee 1.38 53h) tr Farmer City Golf Course Lake = (Llinois) aha SC 0.75 455 tr Upper Twin Lake (Illinois). . sae eae. 1.08 392 tr Black Jack Lake ea a 4.00 280 tr. Delta Pond (Illinois). . 0.80 234 10.7 Onized Lake (Illinois). . 2.14 206 (0), Duck Pond, Pollywog Assn. ‘(Illinois)... We Beet i 3.10 673 al Triangle Pond, Pollywog Assn. (Illinois). eee 2.50 487 aS Duck Island Farm Wake (llinois)s-e ae oer 4.90 316 tr. Sportsmen’s Lake (Illinois).................... BETO 341 tr. Lower Twin Lake (Illinois)................... 1.36 778 1.0 cake Glendale (Ilinois):.. ...... 02.008 nee. bee 82.00 86 5.0 pas unpub- ished Park Pond Slough, Pollywog Assn. (Illinois)..... 0.47 371 10.4 |Present study Mississippi River Upper Mississippi Been Bo ohare Stance) River Conservation Area 1 ae 1.07 391 0.2 |Committee 1947, Area a 1.76 695 1.4 1948 Backwaters, “Savanna (Illinois) Slough 1.. eR of 2.16 171 0.3 Slough 2.. 0.95 423 1.0 Lamer’s Upper Pond (Illinois)... 0.25 516 4.7 ~|Elder & Lewis 1955 Lamer’s Lower Pond (Illinois). . 0.50+ 285 Seo 8 Intinois NaturAL History SurRvEY BULLETIN best fishing for warmouths in experimental areas of central Illinois is in moderately clear water, the poorest fishing in tur- bid waters. Jenkins, Elkins, & Finnell (1955:42) found the slowest growing Oklahoma warmouth populations in waters known to be continuously turbid. In a comparison of fish populations in two southern Illinois ponds, one of which was more turbid than the other, Elder & Lewis (1955:394) reported that repro- duction and the coefficient of condition of warmouths was better in the less turbid pond, although growth was somewhat bet- ter for the warmouths in the more turbid pond. As the two ponds differed in age, size, density of fish population, and fertil- ity, turbidity was not the only factor that might have been responsible for differ- ences in growth. Depth Several field observations indicate that small warmouths remain in shallow weed Vol. 27, Art. 1 beds, or other dense cover, for their food and protection, whereas larger warmouths spend more time in deeper water. In Venard Lake, small warmouths were collected in great numbers from the riprap- ping along the dam, fig. 3, where they were hiding beneath submerged rocks. Sel- dom were large warmouths taken from under these rocks; except during the spawning season, most of the fish of larger sizes were taken from deeper water. Relatively few warmouths of desirable sizes were found in a weed-choked channel of Park Pond, although many large indi- viduals were taken in Park Pond proper. In Park Pond, winter collecting with an electric shocker turned up large numbers of small warmouths in shallow water close to the banks, although at that time the sur- face of the pond was covered with thin ice. Apparently, small warmouths do not leave their protected hiding places in shal- low water even during cold weather. This behavior contrasts sharply with that of bluegills. Bluegills, most numerous of the Fig. 3—Warmouths, stunned with an electric fish shocker, near the riprapping of the dam at Venard Lake. August, 1957 kinds of fishes collected along the banks of Park Pond through summer months, were taken there in far fewer numbers after the beginning of cold weather. In the win- ter, bluegills of all sizes were ordinarily collected in compact schools in deeper water. Large warmouths were likewise in relatively deep water but showed little tendency to group together. The conclu- sions suggested here are that (1) war- mouths of less than 5 inches total length remain in protective cover in shallow water the year around; (2) large individuals spend more time in deep than in shallow water; (3) warmouths exhibit no tendency to group together during the winter months. Dissolved Oxygen Observations in the field and laboratory indicate that warmouths may survive in habitats having low concentrations of dis- solved oxygen. An example of the toler- ance of warmouths for a low oxygen con- centration was observed on April 27, 1947, when 23 of 50 fish in an overcrowded aquarium were found dead; of the 50 fish, 070 060 fe) a fo) 040 030 020 OXYGEN CONSUMED, CC./GM./HR. 2 ro) .005 .000 Rae Ol oo MOAT DISSOLVED OXYGEN, CC./L. BP Ora Fig. 4—Amounts of oxygen consumed (cubic centimeters per gram per hour) by warmouths in water of different oxygen tensions (cubic centimeters per liter) at 20 degrees C. Larimore: Lire History oF THE WARMOUTH 9 about half were warmouths and half were bluegills. Of the 23 fish that were dead, all were bluegills. The few bluegills that were still living were light colored and obviously sick. All warmouths, however, were alive and showed very little or no distress. Warmouths are among the last species of fish to die when collections of live fish are concentrated in tanks, tubs, or buckets containing water. For example, on No- vember 12, 1949, between 9:30 a.m. and 2:15 p.M., many bluegills and warmouths were taken alive from Park Pond. The morning and afternoon collections were placed in separate fish tanks in a truck. No compressed air was supplied to the water in these tanks, and consequently many fish were dead when the tanks reached the laboratory late in the after- noon. In the tank containing the morn- ing collection, all of the bluegills (about 30) were dead, whereas 40 warmouths in the same container showed only mild signs of distress. Of 50 bluegills collected in the afternoon, only a few remained alive, whereas 24 warmouths collected at the same time and kept in the same tank were in excellent condition. In order to test the tolerance of war- mouths for low concentrations of dissolved oxygen, Leonard Durham and [I measured the oxygen consumption of warmouths con- fined in water containing different amounts of this gas. Dr. C. L. Prosser, Professor of Physiology, University of Illinois, sug- gested the laboratory procedures for these tests, the results of which supported our observations made in the field. The Winkler method was used to deter- mine oxygen concentrations of two sam- ples of water, one sample taken at the be- ginning and one at the end°of the test period. The difference between the two samples in cubic centimeters of oxygen per liter of water multiplied by the number of liters of water in the test jar (volume of jar minus volume of water displaced by fish) gave the total amount of oxygen con- sumed by the fish; the number of cubic cen- timeters of oxygen used per gram of fish per hour (cc./gm./hr.) was then calcu- lated. The amount of oxygen used by the test warmouths in water at 20 degrees C. ranged between 0.05 and 0.07 cc./gm./hr. 10 Ittrno1is NaturRAL History SurvEY BULLETIN as long as the available dissolved oxygen in the water exceeded 3 cc. per liter, fig. 4. The consumption of oxygen by the war- mouths dropped off abruptly from 0.03 cc./gm./hr. when the dissolved oxygen in the water was 2.5 cc. per liter to less than 0.01 cc./gm./hr. when it was 0.5 cc. per liter. The concentration of dissolved oxy- gen at which oxygen consumption by the fish declines abruptly is the critical oxygen tension or the oxygen concentration at which the metabolic rate of the fish begins to fall off rapidly. Even though this crit- ical oxygen tension is not lethal immediate- ly it will ultimately be so. For the war- mouths in our tests, the critical tension figure was found to be 2.5 cc. per liter (3.6 p.p.m.) at 20 degrees C. This critical tension figure is close to that determined by Moore (1942:327) after he had studied 13 species of fresh- water fishes, including the largemouth bass, the bluegill, the pumpkinseed, and other species which are often associated with the warmouth. Moore stated, “In general, oxygen tensions of less than 3.5 p.p.m. at temperatures of 15-26° C. are fatal within 24 hrs. to most of the species tested.” Although the warmouths in our tests were removed before complete asphyxia- , tion, several specimens had reduced the dissolved oxygen in the water to low con- centrations. Only 0.21 cc. of oxygen per liter of water remained at the end of one test on warmouths, 0.24 cc. at the end of another. Conclusions from the tests described above not only suggest reasons for survival of the warmouth during periods of water conditions that are generally considered un- favorable to fish but also indicate certain of the warmouth’s physiological character- istics that are associated with its habitat selection. Turbid waters, organic silt de- posits, and dense vegetation, usually re- garded as typical features of warmouth habitats, are associated with high oxygen demands and, at times, low concentrations of dissolved oxygen. Stream Gradient The abundance of warmouths in flow- ing waters appears to be related to stream gradient; the occurrence of these fish in- Vol. 27, Art. 1 creases from rare in fast-moving creeks to common in sluggish streams with a low gradient. I have collected warmouths in several central Illinois streams having gradients between 8 and 14 feet per mile, but I have never collected them in large numbers. Nelson (1876:37) mentioned that Professor S. A. Forbes found this species “very common” in the Illinois River and tributaries through central Illinois; and Forbes & Richardson (1920:246) reported it “common” in southern Illinois, “mainly in the smaller streams.” The IlIli- nois River has a generally low gradient, and the small streams of southern Illinois in which warmouths are now commonly reported have low gradients. FOOD HABITS The food habits of warmouths from Park Pond and Venard Lake were studied through a period of 12 months. The ob- jectives of this study were to determine the kinds and amounts of food consumed and the ways in which food habits of the war- mouths were influenced by habitat, season of year, daily feeding periods, size of indi- vidual fish, and competing species of fish. Consideration was given to the possible ef- fects of two different computing methods on the interpretation of the data. Methods of Study For the food habits study, warmouths were collected from Park Pond and Ven- ard Lake, for the most part at monthly in- tervals over a period beginning in October, 1948, and ending in September, 1949. Heavy ice prevented collecting from Park Pond in January and from Venard Lake in January and February. Extra collec- tions were taken from Park Pond during the summer months as a means of deter- mining diurnal feeding periods. No attempt was made to measure the relative abundance of food organisms in the water areas. A total of 515 warmouth stomachs were collected from Park Pond; of these, 124 were empty and 391 contained food in varying amounts. Of 413 warmouth stom- achs taken at Venard Lake, 57 were empty and 356 contained food materials in meas- urable amounts. August, 1957 All fish were taken with a rowboat fish shocker (Larimore, Durham, & Bennett 1950), fig. 5. Regurgitation of food by the fish was not caused by the shocker as it was used in this study. While the fish’ were fresh, their stomachs were removed and LariMoreE: Lire History oF THE WARMOUTH 11 Survey. It was found to be convenient and reliable. When items were measured by both methods, the volume determined by one method agreed closely with the volume determined by the other. The sum of vol- umes of the different kinds of food in each Fig. 5.—An electric fish shocker being used from a rowboat to collect warmouths in Park Pond. placed in cheesecloth bags; the bags were labeled and placed in formalin. Other parts of the digestive tracts were discarded. In the laboratory, each stomach was first studied as a unit. The contents were removed and their total volume was meas- ured. Then the contents were sorted under a dissecting microscope (magnifi- cation 9 to 48 times) into various taxo- nomic categories, table 5. —The number of individual organisms and the volume of each kind of food were determined. Volu- metric measurement was made by one of two methods: large, irregular masses of food were measured by water displacement in a calibrated centrifuge tube; small, compact items were measured by compari- son with cork blocks of known volumes. This second method was devised by the late R. E. Richardson, for several years employed by the Illinois Natural History stomach was checked against the total vol- ume recorded for each stomach when the contents were removed. After data for the sorted food materials had been tabulated, calculations were made that involved (1) the percentage of stomachs in which each kind of food oc- curred (frequency of occurrence), (2) the average number of items of each kind of food in the stomachs containing the food (average number of items), (3) the aver- age of the percentages of volume com- prised by each of the kinds of food in each of the stomachs examined (average of vol- ume percentages), and (4) the percentage of the total volume of all foods repre- sented by each kind of food (percentage of total volume). These calculations and similar calculations for largemouth bass used with the warmouths of Venard Lake are summarized in tables 6-12. 12 Ittrnois NATURAL History SURVEY BULLETIN Vol. 27, Art. 1 Table 5—Food organisms taken from the stomachs of 391 warmouths from Park Pond, 356 warmouths from Venard Lake, and 99 largemouth bass from Venard Lake; also, for each kind of organism taken from the stomachs, its occurrence rating, based on the number of stom- achs in which it was found: abundant (A), common (C), rare (R), or present but with no record of abundance (X). Foop ORGANISM Cestoda Proteotenhialidaey. civ liek oe pee eee eas Palo nea eee C ee Bryozoa Plgmnatellasspy Cone ica ee en ae SO ee Annelida MUR BOCH ACER. SeGiton S42 ti licg oc atte Gastropoda Planorbidae Gyraulus apaab parvus gees Ancylidae. . i Ly mnaeidae. . Physidae Phosa integra Taldeman: 25.230 i 08th. ae = Piysa probably: grime Says oveee oe we oes Cladocera Simocephalus sp.. Daphnia sp.. Chydorus (7) § spe Alona (?) sp.. Copepoda ENELADE SDs oe see eI ay tT EE n thg. ORtACOd ater. se ee best th ea nie, eee ey tae Amphipoda Eygleila azleca (Saussure) o-2 io) fact yajen eee tk Isopoda Asellus sp.. Decapoda. . Procambarus 's blandingii acutus (Girard). . Orconectes virilis (Hagen) Orconectes propinquus 5 propinguus ees ae Araneae AV COSID EL MN a eo ete Michele ce at ale Maun Wits erie Oe ale Rt enna e te ghar a eee a Pisauridae Dolomedes triton sexpunctatus Hentz........... Hydrachnellae Pimnesta faletda Woche ge Mes LAAT ETL GUS SSP cftey hae tn ean Fo CE tS aL OR eae Collembola (Roduraaqualicg linnacus: same sok aes ee ee Ephemeroptera Caenis sp.. Siphlonurus sp.. Hexagenia limbata (Serville) . . Odonata _ Zygoptera. . Argia apicalis (Say)... Enallagma basidens Calvert... E. carunculatum Morse. . E. civile (Hagen). . E. signatum (Hagen). Ischnura posita (Hagen). TI. verticalis (Say).. Perithemis tenera ak Say). ARISODEerals «ste te Celithemis sp.. Epicordulia princeps (Hagen) .. Erythemis simplicicollis (Say). Sit on ae Leucorrhinia sp.. Libellula pulchella Drury. Pachydiplax longipennis Berek Tet, aN Park Ponp | Warmouth AMMO SP PLS O et Cento oO “> Wad VENARD LAKE Warmouth Le ass R R R R A A A R eso R R A Cc C Mer R A eh Ged A A x x xX x C C A A A A A A Rens oe KE x five x A A xX x ye xX x Dine August, 1957 LarimoreE: Lire History oF THE WARMOUTH 13 Table 5—Continued. Park Ponp VENARD LAKE Foop ORGANISM Warmouth Warmouth rea SE Plathemis lydia (Drury).. 2 CIES CSM. | tak tae Pare tp ole A Lk Soh Cnn NO ad xX Sympetrum obtrusum (Hagen). ; Ain Be Pada Aes ae ce aA Ry Tetragoneuria sp.. EBs Hemiptera SOs Ae TNC pies es cash eala OS newer HRCI TC AG ay aia ce aae ee titre Were a oh cte en eye Rees Nepidae I REN TICNTETS SIO) or tas ace PERT aE TT eee eee Belostomatidae IRVINE SOG og ROS ered cee ORO Fe Veliidae RVIDGRODHILGISD Mia fer ease es a eee es RUEPRODATO. 3 obs bets oe hae a ree a ee Gerridae (QaA PS’ Soc wed Cece BO NCL OR at teach Homoptera ‘esta NFACIGIEES Teese eked, cot ae aie ee a | Neuroptera SUSSBITINS. bBo b Oo eee oo ae ere eae eer a en R Megaloptera Sialidae SHGIES SIDER AL OER eae dele era herd Aare CRS ee a Hymenoptera [POVAaRS LENE» sg Slee Beteiac as Brrr act Seen ae Ne Apidae AE ens MAMIACUS oe Oe Pan. os ade oe eae ew Ry a (hace vaneede ses Coleoptera Haliplidae EASE OSS CU Re A NSE re cs eee R C IE GBNES ED 5 DEAR ees tLe aR ESE ee © Dytiscidae UITEES SSO 5 os tor ARE PAT ata eae R LP ere BG Bho ee R SA ea eA APT ate h-Vewre Tals cnaye «ja salva Pde dneg oh. fen ass alae te Gay ste & 5 Le RURe Sklay he Hydrophilidae REL GOASES Dei ee ee a era tp hvek otek WIG DUVENHUSISD ay Paitin donakeNl se ohne eS eee jaa ER Locus vaca. SR Se a Me PS a ae eae eR ae 2 oat ee cr eee ea R Chrysomelidae | GREP eI EE hai aE sth oe oie me IE Lire et SMe aN atta mat ads ol R EJateridae WUD TGS SONS oa OE Nea i ae A aa a eae Scarabaeidae | Ataenius sp.. REY CAPER ed IE ea ee R R Phyllophaga probably futilis. . 1M was oe ae eRe aad ae tie Trichoptera Hydroptilidae. . ? Oecetis cinerascens s (Hagen). . Oecetis inconspicua (Walker). sees ee: i Ge Teds kN pct ee A Ec Oxyethira sp... BS TEA) si el et Sn ee ae I i ta ol ae x xX Orthotrichia sp.. 1 ey stag tea ante Rot Sacre Nestea eats Ree eee Oe th cue Gate Diptera SOR OMOINIG Aes licvare Sins. ahaa hus saccave osreb aut = MME CI se. Sree he pe ay ote sn We Foe ns hehe oe Culicidae (CU RGIAGEREIS SD othe c haa SNe Ere Oo eT cer ae ata Syrphidae EPOSHES Soe non Ges Ae se CP PER POMIVIdAc Ee Sones eset Ke, Shea RELIG eee rt ne ye ee a ed tn eh Pisces Chaenobryttus gulosus (Cuvier)................ Lepomis m. macrochirus Rafinesque............ eee WMigcroprerus salmotdes (Lacépéde)........... 6. |e ces. ct eae Za KM eke) oN @el vel apse rele) o) a Gane ceca x vole) a0 Ane wz > y°) > PK Q0 AAA BZ o) > Gk (2 14 Ittinois NatuRAL History SurvEY BULLETIN The reason for calculating the volume of each kind of food by both average of volume percentages and percentage of total volume is that these two calculations give very different expressions of volume. The average of volume percentages is influenced by frequency of occurrence of a kind of food but not by the size of a stomach nor its fullness; thus, it gives the stomach con- tents of a small fish the same importance as those of a large fish and favors small food items that appear in a high percent- age of stomachs. On the other hand, the percentage of total volume anh nees the importance of large food items and there- fore the diet of large fish. Since the per- centage of total volume of a food is not affected by frequency of occurrence (the percentage of stomachs in which the food occurs), it does not reflect the food habits of individuals of a population but rather the foods consumed by the population as a whole. A few large items might be important as food to a few large fish but of no value to the smaller members of that population. Although the above differences have been discussed in other food studies (Ben- nett, Thompson, & Parr 1940:18; Mar- tin, Gensch, & Brown 1946; Beck 1952: 398; Reintjes & King 1953: 96), a complete food analysis employing both methods has not been published to illus- trate erroneous conceptions inherent in references to volume as a percentage with- out defining its derivation or meaning. Principal Foods in Two Habitats Food items of many kinds were found in the stomachs of warmouths collected from Park Pond and Venard Lake, table 5. Considerable differences exist in the taxo- nomic levels to which the food items were identified.* A similar situation is found in most food studies of fish and generally is due to difficulties in the exact identifica- tion of fragmentary animal remains. In *Identifications of selected pee were made by the following persons: Dr. H. H. Ross (Trichoptera), Dr. ee Sanderson (Coleoptera and miscellaneous groups), Dr. J. Stannard, Jr. (Hydrachnellae), Mrs. Leonora K. Gioyd (Odonata), Mr. Robert Snetsinger | (Araneae), Dr. E. Moore (Hemiptera), and Dr. W, R. Richards pity. all at the time of this study with the Illinois Natural History Survey; Dr. D. Burks, with the Division of Insect Identification of the nieces States De- partment of Agriculture (Ephemeroptera); Mr. Glenn R. Webb. Ohio, Illinois (Gastropoda); and Dr. H. H. Hobbs, Jr., University of Virginia (Decapoda). Vol. 27, Art. 1 groups such as Odonata, individuals of which were found in large numbers in the warmouth stomachs and which were rep- resented by many species not distinguisha- ble except by a specialist, only selected collections were identified to species. These identifications extended the number of spe- cies found in warmouth stomachs but pro- vided no information as to the relative abundance of individual members of these species. In both frequency of occurrence and volume, the foods of warmouths collected from Park Pond differed from the foods of warmouths collected from Venard Lake, tables 6-11. The six foods that, on the basis of their volume and the percentage of stomachs in which they were found, were judged to be most important for each of the two areas are considered below. Less important food groups that appeared to be significant in the warmouth diet are men- tioned as miscellaneous foods. Park Pond.—Four of the food groups listed among the six most important in Park Pond were included among the six most important in Venard Lake. These were the Decapoda, Ephemeroptera, Zy- goptera, and Anisoptera. Trichoptera and Pisces, among the six most important in Park Pond, were comparatively unimpor- tant in Venard Lake. Decapoda.—Crayfish, which ranked first in bulk as a warmouth food at Park Pond, made up 50 per cent of the total volume consumed by warmouths collected from this pond. Decapods were found in 19 per cent of the stomachs; the average of their volume percentages amounted to 14. Cray- fish were important for a few warmouths (generally the larger ones) but of rela- tively little value to the others. Ephemeroptera.—Forty-one per cent of the warmouth stomachs from Park Pond contained mayfly nymphs (no adult may- flies were found). These nymphs com- prised less than 1 per cent of the total vol- ume, but the average of their volume per- centages was 10. Nymphs of three genera were identified: Caenis sp. was the only mayfly abundant in the stomachs; Siphlo- nurus sp. was uncommon and Hexagenia limbata was rare. Zygoptera.—Damselflies (mostly nymphs) occurred in 34 per cent of the stomachs of Park Pond warmouths. They August, 1957 made up 2 per cent of the total volume; the average of their volume percentages was 16. Eight species (four genera) were identified ; no tabulation was made of the percentage comprised by each species. Anisoptera.—Dragonflies were less im- portant than damselflies in the stomachs of Park Pond warmouths. Dragonfly nymphs, found in 14 per cent of the stom- achs, made up only 2 per cent of the total volume of food ; 6 was the average of their volume percentages. Nine genera of drag- onflies were identified. Trichoptera.—Caddisfly larvae occurred in a high percentage (36 per cent) of the Wwarmouth stomachs from Park Pond but amounted to only 3 per cent of the total volume; 13 was the average of their vol- ume percentages. The specimens identified belonged to the families Hydroptilidae and Phyrganeidae. Pisces.—Fishes ranked second to cray- fish in total volume of food in the stomachs of Park Pond warmouths. They made up 36 per cent of the total volume and oc- curred in 18 per cent of the stomachs; 14 was the average of their volume percent- ages. Small sunfishes were most common, but single individuals of several species other than sunfishes were included. Miscellaneous—Among the food items somewhat less important in the diet of Park Pond warmouths than the six listed above were the amphipods. These occurred in 24 per cent of the stomachs from Park Pond but were absent from the Venard Lake collections. Diptera larvae or pupae (mostly chironomids) were identified in 38 per cent of the stomachs of Park Pond warmouths but comprised less than 1 per cent of the total volume of food. Sixteen per cent of the stomachs contained cladoc- erans. Venard Lake.—The most striking dif- ference in diet between the warmouths of the two water areas was in the number of fish consumed. Fish were found in less than 2 per cent of the warmouth stomachs from Venard Lake in contrast to 18 per cent of the stomachs from Park Pond. Isopoda.—Eleven per cent of the total volume of food in the stomachs of war- mouths collected from Venard Lake con- sisted of Asellus sp. (a form previously considered 4. communis), which occurred in 27 per cent of the stomachs examined. LarimorE: Lire History oF THE WARMOUTH 15 Isopods were found in only about 1 per cent of the warmouth stomachs collected from Park Pond. Decapoda.—Crayfish occurred in only 10 per cent of the warmouth stomachs col- lected from Venard Lake and comprised 15 per cent of the total volume of food in these stomachs. They ranked second in percentage of total volume in Venard Lake stomachs, but the percentage was low in comparison to that in Park Pond stomachs (50 per cent of total volume). Ephemeroptera——Mayfly nymphs, like crayfish, comprised 15 per cent of the total volume of food in warmouth stomachs from Venard Lake, but they could be con- sidered more important as food because they were found in a larger percentage (43 per cent) of the stomachs. An average of 10 nymphs per stomach was found in the stomachs that contained mayflies. Caenis sp. was the mayfly most often found in warmouth stomachs from Venard Lake. Siphlonurus sp. was found in a larger per- centage of stomachs from Venard Lake than from Park Pond. Zygoptera—Damselfly nymphs ranked fifth in frequency of occurrence (14 per cent of the stomachs) and fifth in total volume (7 per cent) of food in the war- mouth stomachs from Venard Lake. Anisoptera.— Dragonfly nymphs or emerging adults comprised the greatest volume of food (38 per cent of total vol- ume) in the warmouth stomachs from Venard Lake. They were found in 17 per cent of the stomachs. Nine different spe- cies of dragonflies were recognized. Diptera.—Forty-four per cent of the warmouth stomachs from Venard Lake contained Diptera larvae or pupae. Dip- terans comprised only 2 per cent of the total volume; 12 was the average of their volume percentages. Five families of Dip- tera were represented. Miscellaneous.—Caddisflies were found in 21 per cent of the stomachs from Ven- ard Lake, a smaller percentage than in the stomachs from Park Pond. Cladocerans occurred in 51 per cent of the stomachs from Venard Lake, ostracods and cope- pods in smaller percentages of the stom- achs. Cestodes, annelids, and collembolans were represented in the stomachs of war- mouths from Venard Lake but not in the stomachs of warmouths from Park Pond. 16 Ittino1is NATURAL History SuRvEY BULLETIN Vol. 27, Art. 1 Table 6.—Stomach contents of 64 warmouths collected Sromacus From 38 Fisu or Less Tuan 5.0 INcHES Average Foop ITEM Percentage | Number of of Stomachs | Organisms Containing | in Stomachs Organism | Containing Them Average of | Percentage Volume of Total Percentages Volume RSARETOIMMIE SE ahs oie bt yt ks eth ns 8 U8 EATS Sie be ant MR aan ae ry teat! a Coinenoda se ess. hele Sat ate Ph 3 Tee i pa age Me OM ERD eae rig gee 13 EASED «ERS RG Renae rare Pe oe ee s SCN 82 ic sigs wiles Sosa ae he ite Ee 0 Iai GET Ina nie de Oar ea orcad He sinres RR BAE 5 Pilemerapeeta: a: U0 Sk eins Pe RU 32 Ppinearihel ie 3-6 gah roe ee ee 32 TRMETRIER ALD catenin iS k's vin eae eee 21 TREE FSS Seat So See Sai PS i AE OL 5 Piemimitetd: neste ee so Yin prea 3 Galssstrta trast hh 2S 3 Retentions As ates ae 16 | EE apa anette tba Rp pce Rte Mant oer 24 IS EER Soo ee Sato os oe Sean Ie 21 Hilamentousialpaess: tac sess nee ee ie ee 5 Pieheriplants ? ois. ab) eet ie et ae 5 Gen gnicdebrists 020i sepsis ies Cte toes 0 aN eNore . — St DO tO OF — nn ind Sor SonursSursssog oo SCAPYUNODHOAWOHOHN’ AN CUDHDOBPHEOREPOODUNHORW NW Table 7—Stomach contents of 79 warmouths Stromacus From 52 Fisy or Less Tuan 5.0 INcHEsS Average Baondlvru Percentage | Number of of Stomachs | Organisms Containing | in Stomachs Organism | Containing Them Average of | Percentage Volume of Total Percentages Volume EVOL Reem eat esa ae tote er 0 paneepeact ls My net ee le Ree 8 Rolie rae: intl eee ee eg ad 285 Ree S CE co ate ach i Nok es Bh ctu as 13 CSE COU A hse serine me caans, ah cha taal ooo - AeA IIe eae PSOE oP uct Peck 37 spate eer seks Aaah (Nc Steinberg 2 RSP hs oie a ek Uh a ey ater oho ges 13 Momewmerapieta. 23...) a+ /o00} 5,44 bn ee es 56 2 TEE ah Se NORE ac A/S mane iret ea 52 PRE TT eet tage Sorbet SE OD 8 Pirie ty Ee nee pee Be ee 2 RintnenOptee as «5 atl. oats ee hs 0 Goteanier: agus: tec, het ees 0 RRRIOHAD Cra: 2. orcs ee ete > Be ces a tiers 40 Le eR Ee Tae, erie 25 Pane ee as. Sk oo Oe rs ee ea 2 Rilamentousaleae . 9) Pisses cae eee ek 6 Riboeiakiss . ): +. 4de com Fak abides 8 OP aHICHIE BIS, «2 Uc), ert ah ehtoae et whee 23 YQUnOO HDReKeMnonooodefWTTE DANK OS nN — in © Ne OK OK NnNODOONNOWONS — — to NooSanccouhunorgsosso , mE NWOOEPENNEENNWRUHO PPRNAPOOCHENONWHEN’ — August, 1957 Percentage of Stomachs Containing Organism in) Nore FOCCMAHNNHWUHOOAO Percentage of Stomachs Containing Organism Larimore: Lire History oF THE WARMOUTH 17 from Park Pond in December, 1948, and January, 1949. Sromacus From 26 Fisu or 5.0 IncHEs or More Sromacus From A. 64 Fisu ee : Average ; umber o Percentage | Number o Per- Organisms Average of | Percentage of Stomachs} Organisms average of centage P Volume of Total napieed E Volume in Stomachs Pp Vol Containing |in Stomachs Pp of Total Containing EPeentages ace Organism | Containing |* “TSP @8€S) Volume hem Them 0 0.0 0.0 5 2 0.4 0.1 1 (ee tr. 9 4 2K tr. 0 0.0 0.0 2 1 tr. tr. 0 0.0 0.0 8 2. 1.9 0.1 1 (iit 0.1 3 1 1a, 0.1 1 16.2 45.0 9 1 6.6 36.6 1 0.8 0.4 3 1 0.4 0.3 » 4.0 0.1 23 3 1G 0.4 1 15.0 Ons 28 » 18.8 13} 2) She fe DAD 16 1 12.6 545 0 0.0 0.0 3 i 1.8 fates 0) 0.0 0.0 2 1 0.1 Ons 0) 0.0 0.0 2 i. i125 0.9 1 0.1 0.4 11 1 4.8 0.7 1 3.9 Onl 20 1 31.5 0.1 1 46.8 Sled 33 1 28.3 52.9 0 0.0 0.0 3 On. 0.3 OLE iL} 0.3 9 0.8 0.3 8.5 0.1 6 3.4 0.1 collected from Park Pond in March—May, 1949. Sromacus From 27 FisH or 5.0 IncHEs or More Sromacus From Aut 79 Fisu Average ele ee : Number of Percentage | Number o Per- Organisms aes of | Percentage of Stomachs| Organisms Average of centage : olume of Total es - Volume in Stomachs Pp Vol Containing |in Stomachs Beeccny of Total Containing EE CeMBARCS ie tals Organism | Containing |* “TSS"*8°S| Volume Them Them i Sei tr. 1 1 is tr. 1 B85 the 6 1 ets! 0.1 0 0.0 0.0 15 3 3.4 ine 0 0.0 0.0 9 3 De) fits 0) 0.0 0.0 3 2 0.3 tie 1 On2 (ae 25 2 Bete Onl 0) 0.0 0.0 1 1 ele tr. 1 43.1 60.9 29 1 ied Efoy, 2) 2 0.8 iL Al 40 2. 7.4 es 1 8.4 0.8 47 2 20.9 2.9 1 4.5 0.8 10 1 eel te 1 ths fiige 3 1 0.1 tr. 1 30 0.2 1 1 1.0 0.1 1 0.5 fitz 3 1 0.2 tr. 2 op 0.3 33 3 9.0 183 2 1.4 0.2 39 4 10.6 (Ory 1 11.6 29.7 6 1 Sy Il Do 0.6 Ont 5 0.6 Ont 6.0 Sail 23 2.8 4.7 9.4 0.9 24 9.5 1.8 18 ILLinois NATURAL History Survey BULLETIN Vol. 27, Art. 1 Table 8.—Stomach contents of 131 warmouths Sromacus From 98 Fis or Less Tuan 5.0 INCHES Pine ae Percentage umber o Fae of Stomachs | Organisms Containing | in Stomachs Organism | Containing Them KSamtraporia so: ite Site coe eis sme bade sy lade aa 14 Pianeta. sei ca lass SRS OE nes 24 ROIETHRIA AY (ts CRE Ss ys a prose OS Bee 10 WStraCOd dace een aks oe a eat mae 5 PAPA ET NLS i'd ais IS re, piece ST OR 35 CRP oe pion god sack wi we Oe ew Re 16 Araneae. Oe Sapa ean Hie tee Patenma tt Waites 1 Ephemeroptera. . SA, Tote EAE ot Nes 58 Zygoptera. . Boe ey Ne ics AG ils A ence ee 47 Bincgefeta ly eee we ees 17 | 3 FETE Ee Rh a a Oe ie nae OE, SRE Ctr 6 Blgmeutera cache val ec Oo oe eee eek 0 @olepnters latvse-i. ie: es hehe ne if GCoaleopteta adults. p14 253 sue hose) oo aes 4 LSS oats ieee hia ead renee 52 Diptera. . RR AREY Forehand aus de eae ie 49 Pisces...... SAG Arran eet Rite Ma Lae pales sh 16 Banmeiousaloueee hss ok MS dete a 4 BTiS et HAINES ie re pitta ck sta gis eG ee a Po reals 11 Gieauic debis hea i ee 17 Average of | Percentage Volume of Total Percentages Volume a _ OO — NEONwHNOT COUNhOSHG OOS a CURE UAD! BNE RAWH Ww Ses Sek — KBHNNAODWH’ nN VON RP ORPEN BEEP ORUWD _ Table 9.—Stomach contents of 117 warmouths collected from Stromacus From 93 Fisu or Less Tuan 5.0 IncHEs Average Foop Item Percentage | Number of of Stomachs | Organisms Containing | in Stomachs Organism | Containing Them Average of | Percentage Volume of Total Percentages Volume CAS ELODOU EN Gis fou, vos cede sbouareni an Rae eS 11 2 GIAGOCEE AT ete eee Se pan lan teak 20 17 ORE DORA Aigo. = Sets tis peak Be ama oe 15 Meter ae ys, sUR Ee cack tes ee miele ere oe 3 MTPPOR Le rerio te ih gecs She os eee 35 aa Soc aaa 1 Decapoda. . PAGE UN cast Rke eae ashy cas + Araneae. Seite ae one RPC Mae Bisa ver 1 Hydrochnellae. . Se edn cae a ee ae 1 Ephemeroptera. . FSS areaig Etats Lae ey 49 75 LARS ae eee a aides HCN 24 PURIAFECH ARS yi sols acute eee yeaa ae 15 isp | (i 21 Ree ea ce ae RESO Ale emenn of Wolcapeera WIVAe ahs ei, Ales ae 1 olecptera Maiti. ogkek te oe ee eee 1 ee RU or ee 46 Diptera. . ene et Ue Horie ty SNe mhe ies 55 PIGGES oa. cs ROE ee eo ERT ee 11 Filamentous algae. . REESE Fa acta arte Mr 3 Higher plants. . eta Satan «Daehn te erie 8 8 Cereinae brs! ne eee 14 _— oouneo ONDA WHHL , SOW BNE NNE EE ENWOw Les | i) pues NWNnWwWNat wooo” (> ens) —t — — WBONSWOHEBUNDORPONH OR UN > oSo%NN NDE ON’ August, 1957 collected from Park Pond in June-August, 1949. Larimore: Lire History or THE WARMOUTH Sromacus From 33 Fisu or 5.0 IncHEs or More 19 Sromacus From A ut 131 Fisu peer : ‘ ee : Percentage | Number o ercentage | Number o Per- of Stomachs| Organisms Average of | Percentage of Stomachs} Organisms Average of centage eel Volume of Total nein le Volume Containing| in Stomachs Containing |in Stomachs of Total 0 : C .-. ~|Percentages| Volume Z - «| Percentages rganism | Containing Organism | Containing Volume Them Them $ 1 tr. tr. 11 2 1.6 0.1 0 0 0.0 0.0 18 5 ee 0.1 0 0 0.0 0.0 8 5 12 tr. 0 0 0.0 0.0 4 4 (yi tr. 3 1 tr. (ae 27 3 2.4 0.3 55 1 49.4 733 26 1 20 64.3 3 1 fit. tr 2, 1 tr. the 30 1 0.5 0.1 51 3 8.8 1.0 15 1 5.8 0.3 39 2 16.0 2.8 9 1 6.3 Dell 15 1 5.4 3.2 3 1 0.2 tr 5 1 0.4 0.1 6 1 0.1 tr 2 1 tr. tr. 6 1 0.8 tr. 2 1 0.2 tie 6 1 Beli (0) 5 1 0.8 0.2 27 1 2.4 1.0 46 4 13} .55 4.1 6 4 1.0 fits 38 3 4.7 0.7 30 1 23.8 21.8 20 2 13.4 21.9 27 he? tr. 10 0.5 0.1 24 1.4 0.4 14 12) 0.5 2 De) 0.1 16 4.3 0.6 Park Pond in September—November, 1948, and September, 1949. Sromacus From 24 FisH or 5.0 INcHEs or More Stromacus From Att 117 Fisu ee : hes : Percentage | Number o Percentage umber o Per- of Stomachs} Organisms Average of | Percentage of Stomachs| Organisms Average of centage paca |)s Volume of Total Siew Volume Containing|in Stomachs Pp é Vol Containing |in Stomachs Pp of Total Organism | Containing STEP REES oe Organism | Containing ercentages) Volume Them Them 4 1 il tr. 9 2) DAV 0.1 0) 0 0.0 0.0 16 17 3.0 0.2 0 0 0.0 0.0 12 9 1.3 0.1 0 0) 0.0 0.0 3 3 0.1 tr. 8 2 0.4 tr. 30 2, 5.5 0.2 0 0 0.0 0.0 1 11 0.8 0.2 29 1 27.4 36.1 9 1 8.4 31.9 12 1 8.3 BRA: 3 1 2.4 3.6 0 0 0.0 0.0 1 1 0.1 (Be. 4 1 2.8 tr. 40 ey 10.8 0.5 12 1 6.4 th: 21 Q 10.0 1.0 8 2 0.4 0.5 14 1 5.8 hea 8 1 0.1 (or 9 D De) 0.6 0 0 0.0 0.0 1 1 0.1 fee 8 1 0.6 tr. 3 1 0.2 tr. 25 2 16.5 S92) 42 2 18.3 4.4 12 2. iil 0.1 46 3 Nop 0.6 83 1 26.4 55.6 15 1 11.8 53.8 0 0 0.0 0.0 3 0.4 tr. 21 5.4 0.5 10 1.8 0.6 12 S52) 0.5 14 5.6 0.5 20 Seasonal Trends Each of the various seasons—winter, spring, summer, and fall—designated in the following discussion of seasonal trends in warmouth foods and feeding encom- passes 3 months. The seasons are biolog- ical rather than astronomical; that is, they are based on similarities in the foods pres- ent and utilized by the fish. Winter in- cludes December, January, and February; spring includes March, April, and May; summer includes June, July, and August; fall includes September, October, and No- vember. The degree to which the stomachs from individual warmouths of Park Pond and Venard Lake were judged to be full was found to be of little value as a measure for determining seasonal trends in feeding activities of the fish or relative amounts of food consumed by them in various seasons of the year. The stomachs from many fish contained one and one-half to two times ILLINOIS NATURAL History SURVEY BULLETIN Vol. 27, Art. 1 as much food as apparently full stomachs from fish of similar sizes. A better measure of seasonal feeding trends was found to be the average volume of stomach contents of warmouths of sey- eral size groups. This measure also proved to have its limitations, most important of which were concerned with differences in rates of digestion and daily feeding periods (discussed under “Daily Changes”) that tended to mask the true seasonal trends. Seasonal trends in average volume of stomach contents (empty stomachs ex- cluded) were apparent in three length groups of warmouths taken from Park Pond. In the warmouths of each of two groups, 3.5—4.9 and 5.0-6.4 inches total length, the average volume increased pro- gressively in the three seasons following winter; the average volume in the fall was two to three times that in the winter. Ina group of smaller warmouths (2.0—3.4 inches total length), the average volume of stomach contents was greatest in summer; Table 10.—Stomach contents of 71 warmouths collected in winter (December, 1948) and 81 warmouths collected in spring (March—May, 1949), all from Venard Lake. Sromacus From 71 WarMmouTHS Stomacus From 81 WarmouTHS CoLiecreD In WINTER COLLECTED IN SPRING 6 1 o NS ! vo E|pSu | 5 E155 | 5 Foop ITEM yee Ge So ‘eg SE Soe = 52 v0 Plas to G os v0 fF 2s ‘3 O v5 oD an op on oD op op ga°0 o&§ o § wc a4 O of § os a0 sa (PeO cg Se | Be | gah | PeO 6) See i as HS & reas os & gS RPGs E ue Orn BS-s |S Pec) £5 So | 58-5 [5 Pad) Fo oS HAS |tOeh| ca Be | ans |leOeh| dm Oy SY OZO a a tien sie rate 0 0 0.0 0.0 1 2 ti. ths Amelia ssn seen Se see 0 0 0.0 0.0 1 1 0.4 0.4 Gastropoda. aces aa 3 1 0.7 0.2 0 0 0.0 0.0 Cladocera sar ec ee 96 18 28.9 13.4 56 11 9.6 0.8 Copepoda de tee 3 cts AAS if, 3.0 1.6 20 3 1.0 tr. Ostracoday.ts aac cea 1 1 tr. tr. 0 0 0.0 0.0 Isopoda. . 45 5 27.8 48.5 Bi) 2. 29.1 13E9 Decapoda. . 0 0) 0.0 0.0 2 1 1.0 ss, Hydrachnellae. . 0 0 0.0 0.0 1 1 tr. tr. Collembola. . eae 0 0 0.0 0.0 1 1 tr. tr. Ephemeroptera.. . eR Lo, 56 3 ah 2 12-1 60 24 20.8 20.4 EAGER. aes Ee Se: 4 1 pe: a9 a5 3 8.7 8.1 Anisoptera vena %ct sav ia 6 1 sy 15.8 36 3 23.4 47.8 Neuropteras. 3. 00.5.0. : 0 0 0.0 0.0 1 1 tr. tr. Coleoptera larvae....... 0 0 0.0 0.0 7 1 0.2 0.1 Trichoptera. . 3 1 0.2 0.1 26 5 2ES 2A Diptera. . ery: 48 2 DOS 4.4 38 i 1.4 os Filamentous algae. neers 1 ngage tr. 0.1 2 fie 0.1 Higher plants. . eae 0 0 0.0 0.0 15 0.3 0.2 Organic debris.......... 1 tr. 0.1 23 Ld Tes \ugust, 1957 Table 11.—Stomach contents of 107 warmouths collected LarimoreE: Lire History oF THE WARMOUTH 21 in summer (June-August, 49) and 97 warmouths collected in autumn (October-November, 1948, and September, 1949), ll from Venard Lake. Stromacus From 107 WarmouTHs Sromacus From 97 WarMouTHS CoLLECTED IN SUMMER CoLLecTED IN AUTUMN oe y ae : Els 5 bo 5 E 3 S 2p E Ue eS: We) tee Foop Irem ect es | eee eels Set Neca || eft eae vV oo Za 8 ‘ @ vs oV Bo zak “ 0 vs a2O GES e | go | #20 |DES es | 0 So o ons eal r) 9) » Pee (S26 | 2 | £& | Eee lo2d_| $2 | 2 Goes lire: po eee ee od 6.8 (2a. 6 ose o oa oS-s |S PSE) FS So | 59-5 |S Pee] & 5 re AAs |tOsh| «a AH | ans |\tOek| tm Oa BUS holies ee tac stor al aces 3 1 0.5 1.6 0 0 0.0 0.0 BSCEOPOGA, sic. 6s oe 5 2 Del hes 10 3 3.0 5.6 ReOCEEA ce oe cs tates 32 13 eS One 7 16 8.6 4.5 Mpepodae. sian: geet 11 3 0.8 (a Si 7 7.4 Ons BRIA COC AEY ues casa) ots 16 5 2.4 (0) 31 24 10.0 ES WPI GMAN tase Ne sictcien nue 8 2 Ig 6 0.4 3, 3 Sie Taal CAD OG Alea: ced haikk es 24 1 18.0 35.0 8 1 6.8 44.9 phemeroptera......... 33 4 Ql 6.1 31 6 58, a3 WEOPLen AN. chsh. dei 9 1 5y(0) 3.6 10 3 4.5 4.7 RESO [IGEN oe easy vere 10 2 Vee 2550 16 Ds 10.1 22.8 Emap tena ie press seco 0 0 0.0 0.0 2 2 Ores 0.2 fymenoptera. 2... iy is: 0 0 0.0 0.0 1 1 ites tie oleoptera larvae....... if D 0.8 1.4 2 2 0.2 0.1 oleoptera adults....... 1 1 tr. Ost 2 1 0.4 0.4 OTS eee 34 4 18.7 8.4 16 3 7.4 3.0 iptera.. 40 2 D5 1.2 49 Ti 18.5 4.2 isces. : 6 1 5.0 D5 0 0 0.0 0.0 ilamentous algae a eee 0 0 0.0 0.0 5 0.3 0.4 ligher plants. . Lane 9 ail 0.9 8 0.8 1.0 ganic debris.......... 10 Spall 1.6 20 10.7 2.9 he trend was downward through the sea- ons to the lowest figure of the year in pring. Of some interest is the large number of mpty stomachs taken in the winter from he warmouths of Park Pond. Thirty-four er cent of the warmouth stomachs col- ected there in winter (44 per cent of the tomachs collected in January) contained 0 food. These high percentages may re- lect the influence of partial ice cover and old water on the feeding activities of war- nouths. A large percentage of stomachs mpty at a time in which digestion was low indicated that the fish were going ong periods between feedings. A large roportion of stomachs empty in summer vas due to rapid digestion and reduced eeding activity after midday. Tables 6-11 show seasonal changes in cinds of food eaten by warmouths in Park Pond and Venard Lake, as indicated by nalysis of stomach contents. The following discussion and figs. 6 and 7 emphasize the highs and lows of the sea- sonal trends in foods most commonly found in the warmouth stomachs from the two study areas. Winter.—In the warmouth collections from Park Pond, fish (Pisces) were found in a larger percentage of stomachs in win- ter than in any other season, fig. 6. Cray- fish (Decapoda), which ranked second to fish in percentage of total volume in win- ter, were present in only 9 per cent of the winter-collected stomachs examined (all of them from large fish) and did not com- prise so large a percentage of the total vol- ume in winter as during the spring and summer. Dipteran and caddisfly (Tri- choptera) larvae, cladocerans, and amphi- pods were found in a smaller percentage of stomachs in winter than in any other season of the year. In the warmouth collections from Ven- ard Lake in winter, the animal groups Ittino1s NATURAL History SuRVEY BULLETIN Vol. 27, Art. 1 Table 12.—Stomach contents of 99 largemouth bass collected from Venard Sromacus From 23 LarcemoutH Bass CoLLecTEeD Durinc Marcu-May, 1949 Average Foop Irem Percentage | Number of A ‘|p of Stomachs | Organisms Volt of Total Containing | in Stomachs Pp paces v Rae Organism | Containing ne pd Them KCeStod ante. ce ee SSA ta ae ab ferab ache e eens 0 0 0.0 0.0 GEASEPGDOG Ay Yo MIA wade earn gi Benen sate ge 0 0 0.0 0.0 ltlipeeba ws cies Silos a eoarn ts ele Wis aN 22 70 5.0 1.9 REINA A S53 Vales oat ane ow eae din eas oeaete waren ate 0 0 0.0 0.0 Poa et ey a oe eee rege 39 4 pp ee US SS Decapoda. . + 2 2.9 1.6 Araneae. 0 0 0.0 0.0 Hy -drachnellae. . 0 0 0.0 0.0 Ephemeroptera.. Losey Ra pea wires aE gOS 83 17 10.3 7.4 MyeGpteraa cs tot Ker ah Lacie sree aie ue ia 57 6 16.6 26.3 RBBB Pera, tg ak let sn ih ees oa ee epee 6h 3 36.9 37.8 Blcmapteras 2p. hare seus cop Mn pot ete 9 2 tr. tr. remapicha eS sdije ) aik . Seis R ents layers uctN 0 0 0.0 0.0 Figen ptetas).t cose eta ys (xp rakes ees ah amet 0 0 0.0 0.0 Coleaptcra laude. 32...) Anes ee 0 0 0.0 0.0 Beers Ss gee epee 0 0 0.0 0.0 aes coe 0 0 0.0 0.0 Diptera. . 39 5 1.0 0.5 Pisces...... Bee Ae eMC Sac 0 0 0.0 0.0 Pilsmentons clea ne ee eee 0 0 0.0 0.0 Pheher plants. ge ac.) a ase ep eee 13 Ee cies 0.3 0.2 Geecnic duties... oat ee ees 26 5.0 11.0 found in the largest percentages of stom- achs were cladocerans, mayfly nymphs, dip- teran larvae, copepods, and isopods; each of these groups was in winter at or near its peak for the year in the percentage of stomachs in which it was represented. Fish and crayfish, which in winter led all other food groups in percentage of Park Pond stomachs in which they were found, were not found in any of the Venard Lake stomachs during the winter. Spring.—In the warmouth collections from both Park Pond and Venard Lake, the nymphs of damselflies were found in a larger percentage of stomachs, and com- prised a somewhat larger percentage of total volume of food, in spring than at any other season. Mayfly nymphs were present in a larger percentage of the stom- achs from Venard Lake in spring than at any other season; at this season, they were present in a large proportion of the stom- achs from Park Pond, also. In the Park Pond collections, the per- centage of stomachs containing fish and the percentage containing dragonfly nymphs were lower in spring than at any other sea- son. The fragments of so-called higher plants, mostly rootlets or parts of leaves, that were found in 23 per cent of the stomachs probably were taken accidentally with other organisms. About two-thirds of the stomachs that contained plant frag- ments also contained crayfish. In the Venard Lake collections, isopods occurred in a larger percentage (57 per cent) of stomachs in spring than at any other season, fig. 7. They did not com- prise so large a percentage of total volume in spring as in winter, but their average of volume percentages (29 per cent) was greater and it was greater than that of any other food item taken during the spring. Dragonfly nymphs were present in nearly half of the Venard Lake stomachs collected in spring; the percentage of stom- achs containing these nymphs, the average of volume percentages, and percentage of the total volume were much greater dur- ing the spring than at any other season Annelida, Collembola, Neuroptera, and Bryozoa were represented as Venard Lake August, 1957 Larimore: Lire History oF THE WARMOUTH 23 Lake during the period beginning October, 1948, and ending September, 1949. Sromacus From 32 LarcemMoutH Bass Cot.tecteD Durine June—Avcust, 1949 Sromacus From 44 LarGemMoutH Bass CoLiecteD Durinc OcroBpeR—NovemBER, 1948, AND SEPTEMBER, 1949 Average : wo ; Percentage | Number o Percentage umber o Per- of Stomachs| Organisms ae ee of Pee of Stomachs| Organisms eae of centage Containing |in Stomachs reas = eau Containing |in Stomachs ee: of Total Organism | Containing Percentages} Volume Organism | Containing Percentages Volume Them Them 3 1 0.1 0.1 0 0 0.0 0.0 6 1 fils tte 7 1 0.1 tx: 3 199 3.0 0.4 59 178 23.0 10.1 0 0 0.0 0.0 7 2) tr. th: 0 0 0.0 0.0 9 2 0.4 0.1 34 1 18.5 19.8 9 1 9.0 54.0 3 1 tr. tile 2 1 tr. tr. 3 1 tr. tI. 0 0 0.0 0.0 47 8 2.4 0.9 77 26 24.1 8.7 47 4 17.6 6.3 30 3 5.8 Del 41 3 15.9 10.6 34 2 Sia 9.8 16 1 fies fit: pi] 1 6.0 0.8 3 1 tr. tr. 0 0 0.0 0.0 25 1 38) 0.7 2 1 tk. tr. 19 43 4.1 1.9 0 0 0.0 0.0 9 1 fits tii: 0) 0 0.0 0.0 6 1 0.2 tr. 14 1 gi 0.3 28 2 1.0 0.1 Sy 13 6.8 1.4 38 2 30.4 59.1 5 2 4.5 11.4 0 0 0.0 0.0 2, 0.2 0.1 6 Re 0.1 files 20 0.3 0.4 12 353 0.1 14 2.0 0.7 warmouth foods in spring but at no other time. Summer.—As new broods of young fish became available in summer, a marked in- crease in the percentage of warmouth stom- achs that contained fish was noted in the collections from both Park Pond and Ven- ard Lake. In the warmouth collections from Park Pond, crayfish occurred in a slightly smaller percentage of stomachs in summer than during the spring but attained a peak in the percentage of total volume of food —64.3 per cent, fig. 6. The percentage of stomachs containing mayfly nymphs and caddisfly larvae increased progressively from winter to summer; these groups were found in proportionately more warmouth stomachs taken during the summer than at any other time of year in Park Pond. _ The percentage of stomachs in which dam- selfly nymphs were found was smaller in summer than in spring. In the warmouth collections from Ven- ard Lake, caddisfly larvae were present in a larger percentage of stomachs in summer than at any other season. Caddisfly larvae comprised only a relatively small part of the total volume of food, but the average of volume percentages was greater for cad- disflies than for any other food utilized in summer. Crayfish also were found in a large percentage of the stomachs collected in summer. Although crayfish made up a smaller percentage of the total volume of food in summer than during the fall months, the percentage of stomachs con- taining crayfish was three times as great in the summer as in the fall. Fish were found in the stomachs of only those war- mouths collected in summer. Mayfly, dam- selfly, and dragonfly nymphs comprised smaller percentages of the total volume of food and were present in smaller percent- ages of stomachs in summer than in spring. Fall.—In the warmouth collections from Park Pond, fish comprised a larger percentage of the total volume of food, and crayfish a smaller percentage of the total volume of food, in fall than in sum- mer; the percentages in the fall were nearly equivalent to those observed during 24 ILLtinors NATURAL History SurvEY BULLETIN Vol. 27, Art. 1 FREQUENCY OF PER CENT OF OCCURRENCE PER CENT TOTAL VOLUME CADDISFLIES @ rad DRAGONFLIES S < ig DIPTERA g WINTER | ° 10 20 30 40 PER CENT SPRING 10) 10 20 30 40 4 PER CENT - | 60 FALL 10) 10 20 30 40 50 PER CENT Fig. 6.—For each of the most important foods taken from the stomachs of warmouths col- lected from Park Pond in each of the four seasons of 1948 and 1949, the percentages of stomachs containing these foods (frequency of occurrence) and the percentage of the total volume of food represented by each of these important foods. August, 1957 Larimore: Lire History oF THE WARMOUTH 25 FREQUENCY OF PER CENT OF OCCURRENCE PER CENT TOTAL VOLUME DRAGONFLIES \SOPODS 0) 10 20 30 40 PER CENT SPRING ) 10 20 30 40 50 60 PER CENT 2) ww re = jo) oO e SUMMER 9 0 10 20 30 40 PER CENT FALL PER CENT Fig. 7.—For each of the most important foods taken from the stomachs of warmouths col- lected from Venard Lake in each of the four seasons of 1948 and 1949, the percentage of stom- achs containing these foods (frequency of occurrence) and the percentage of the total volume ot food represented by each of these important foods. 26 Ittinois NAtuRAL History SuRvEY BULLETIN the winter months, fig. 6. Although fish comprised more than one-half the bulk of food in winter, they were taken from only 15 per cent of the stomachs collected in the autumn. Dipteran larvae (largely chi- ronomids) comprised less than 1 per cent of the total volume of food each season but occurred in a large percentage (33 per cent or more) of stomachs each season— the largest percentage in the fall. In the fall collections, dipteran larvae were pres- ent in 46 per cent of the stomachs; the ay- erage of volume percentages for these lar- vae was 9.2. Caddisfly larvae were pres- ent in a large proportion of stomachs and ranked first among all food groups in av- erage of volume percentages. Mayfly and damselfly nymphs were found in a smaller proportion of stomachs collected during the fall than during the summer, whereas dragonfly nymphs were present in about the same percentages of stomachs in these two seasons. In the warmouth collections from Ven- ard Lake, mayfly and damselfly nymphs were present in about the same percentages of stomachs during the summer as during the fall. In November, nymphs of the mayfly, Siphlonurus sp., showed a sudden pulse of occurrence that extended into De- cember. Caddisfly larvae were present in a smaller percentage of stomachs collected in fall than in the summer months. Through- out the four seasons, dipteran larvae were found in consistently high percentages of stomachs—38 to 49 per cent—the highest percentages in the fall and winter, fig. 7. Chaoborus sp., a dipteran larva, was found only occasionally during the spring and summer; but, during the fall months and in December, it was found in large num- bers of stomachs. Gastropods (snails) and ostracods were found in higher percentages of Venard Lake warmouth stomachs in the fall than at other seasons. Daily Changes During the summer, when water tem- peratures were high, digestion in the stom- achs of fish was rapid, and food remained in these stomachs for only a few hours. At this season, it was possible to determine daily feeding periods of warmouths at Park Pond by comparing the percentages of empty stomachs taken in morning col- Vol. 27, Art. 1 lections with those taken in afternoon col- lections, table 13. The influence of indi- vidual fish size, and of size groups repre- sented by few individuals, was reduced by eliminating from the calculations all war- mouths less than 2.0 inches or more than 6.4 inches total length. Only 4 per cent of the warmouth stom- achs collected in the morning were empty, whereas 50 per cent of those collected in the afternoon contained no food. On July 8 and August 1, 1949, collec- tions were taken soon after sunrise and as late in the evening of the two days as fish could be taken with the shocking apparatus without the use of artificial lights. The daily feeding pattern was quite evident in these collections, table 13. Stomachs re- moved from fish collected between 6:00 and 7:15 A.M. on July 8 were “relatively full of very dark material”; in contrast, the stomachs collected between 6:15 and 7:45 p.m. “seemed rather empty, the up- per intestine completely empty, with only the last three-fourths inch of the lower in- testine containing heavy black material representing the early morning feeding.” In stomachs of fish of selected size groups (excluding fish with empty stom- achs), total volumes of the food masses averaged consistently lower (by 24 per cent or more) for individuals taken in the afternoon than for those taken in the morning. Monthly collections of stomachs from Venard Lake in the warm period of the year (1949) indicated for the warmouths of this body of water a daily feeding pat- tern somewhat similar to that of the war- mouths of Park Pond. Of four collec- tions from Venard Lake in the warm months, when the daily feeding pattern might be evident, two were taken in the morning and two in the evening; 13 per cent of the stomachs in the two morning collections and 26 per cent of the stom- achs in the two afternoon collections were empty. The differences between morning and afternoon collections were less evi- dent at Venard than at Park Pond, prob- ably because the collections were taken from Venard late in the morning and early in the afternoon. There was evidence of some feeding ac- tivity by warmouths in late afternoon. Although most of the food materials found August, 1957 Larimore: Lire History oF THE WARMOUTH Zh Table 13.—Number of warmouths in morning and afternoon collections from Park Pond, June 2-September 2, 1949, and number of those warmouths with empty stomachs. Figures in- clude only those for fish between 2.0 and 6.4 inches total length. MornincG AFTERNOON Co.tiection Date Number of Number of Number of Number of Fish Empty Stomachs Fish Empty Stomachs June 2 Moave 3 resin 5 1 June 10 25 3 Seen eee eel ee ete ren eel or July 5 soy ead Sigarees 23 8 July 8 25 0 18 11 EMIGMSCS eS Sin ea 19 1 16 11 PATIOS tab chy sgh, hi edoras cis 16 1 wha ae t Nicaea September.2............. 28 0 we PERE Total number of fish....... 113 5 62 31 Per cent of stomachs empty].......... 4 um 50 in stomachs collected in the afternoon dur- ing the summer were well digested, a few were fresh items; most of the materials were nearly digested or else quite fresh, a situation that suggested a resumption of feeding after a period of no feeding. After- noon feeding during the summer was either very light or it occurred very late in the day, possibly just at dusk when it became too dark for fish to be collected without lights. Influence of Fish Size The yolk supply of warmouth larvae observed under laboratory conditions usu- ally was exhausted within 4 days from hatching; without food, the larvae starved to death in 10 or 11 days at 24-25 degrees C. Ordinarily, the postlarvae began feed- ing at least by the seventh day of life. Stomachs of warmouth larvae collected from outdoor tanks contained a few flagel- lates and ciliates and many bacteria. One or two of the large protozoans made a rather big meal for an 8-mm. larva. When 14 days old, the warmouth larvae ate con- siderably larger organisms, feeding even on small mosquito larvae. Both in natural waters and in the laboratory, warmouths 19 mm. long were observed feeding vora- ciously on postlarval warmouths 5 mm. long. In a study of differences in food taken by larger fish, the stomach contents of war- mouths from Park Pond and Venard Lake were grouped according to sizes of fish from which the stomachs had been taken. Since it was necessary to present these analyses in compact tables, fish from Park Pond were grouped in two length ranges, tables 6—9, and fish of all lengths from Venard Lake were grouped to- gether, tables 10 and 11. Some of the rela- tionships between lengths of fish and foods taken, such relationships as are obscured in the tables by combining data for fish of various lengths, are given in the following general statements. Cladocerans, copepods, and_ ostracods were taken mostly by warmouths less than 3.5 inches in length and were the principal foods of warmouths less than 1.7 inches in length, which only occasionally took small mayfly nymphs or dipteran larvae. Amphi- pods were an important food for small warmouths at Park Pond but were utilized by very few fish larger than 4.9 inches in length. Snails were eaten mostly by war- mouths between 2.5 and 4.9 inches in length. Crayfish were eaten by more large war- mouths than small ones at Park Pond. In contrast, crayfish were eaten by more small warmouths than large ones at Venard Lake, presumably because large numbers of small crayfish were available to the fish there during the summer months. In both study areas, mayfly nymphs were taken by a larger percentage of small war- mouths than of large ones; however, at Park Pond in summer they were taken by 30 per cent of the warmouths over 5.0 inches long. At Venard Lake, where both Caenis and Siphlonurus occurred in large numbers, the nymphs of Caenis were taken 28 Ittinors NaturAL History SurRvEY BULLETIN mostly by warmouths between 2.0 and 3.4 inches, whereas the nymphs of Siphlonurus, which were larger, were eaten generally by larger fish, up to 5.2 inches in length. Caddisfly larvae were eaten by a larger percentage of small warmouths than of large ones; the seasonal trend in consump- tion was somewhat similiar for fish of all sizes. Damselfly and dragonfly nymphs were utilized as food by warmouths of all sizes except those less than 2.0 inches long. Fish were eaten by a greater percentage of large warmouths (over 5.0 inches in length) than of small ones. The average volume of food found in the stomachs of warmouths of various sizes was not directly proportional to the length or weight of the fish; the larger the war- mouth the greater was the volume of food taken in proportion to its size. The stom- achs of very small warmouths occasionally contained relatively great amounts of food, but small warmouths feeding on many small items seldom experienced the ex- treme distention of the stomachs that oc- curred in many large warmouths when feeding on comparatively large fish or crayfish. The percentage of stomachs that were empty was smaller among small war- mouths than among large ones. The per- centages of Park Pond warmouths with empty stomachs were as follows: fish of 1.9 inches or less total length, 3 per cent; fish of 2.0—-3.4 inches, 18 per cent; fish of 3.5-4.9 inches, 24 per cent; fish of 5.0-6.4 inches, 32 per cent; and fish of 6.5 inches or larger, 28 per cent. Small warmouths feeding on many small items apparently had a more certain food supply than had large warmouths, which had relatively fewer large organisms on which to feed. Interspecific Competition Largemouth bass stomachs were col- lected from Venard Lake at the same time the warmouth stomachs were obtained. Be- cause only four largemouths were taken during the winter, their food habits for this season were omitted from consider- ation here. The majority of the bass taken (92 per cent) were between 5.5 and 9.0 inches total length. Of 107 bass stomachs collected, 99 contained food materials, table 12. Cladocerans were found in surprisingly © large numbers in the stomachs of large- mouths up to 7.5 inches in length—791 of them in the stomach of one 6.4-inch bass. © Of the largemouth stomachs collected in the fall months, cladocerans (almost ex- clusively Simocephalus sp.) were found in 59 per cent. Very few were found in the bass stomachs collected in summer. Cladoc- — erans were found in relatively high per- centages of the warmouth stomachs col- | lected from Venard Lake throughout the ~ year; they did not show an increase in utilization by warmouths during the fall months comparable to the increase in uti- lization by largemouth bass. Cladocerans were found in 32 and 37 per cent of the warmouth stomachs collected, respectively, in the summer and fall and in 96 per cent of the warmouth stomachs collected in De- cember. Copepods were found in very few stomachs of the largemouth bass, and ostracods were found in none. Isopods were found in greater percentages of both largemouth and warmouth stomachs col- lected in spring than at any other season. Fish and crayfish together comprised 64 per cent (36 and 28 per cent, respective- ly) of the total volume of largemouth bass food. The percentages of bass stomachs containing fish or crayfish were low in the spring, high during the summer, and low again in the fall. The seasonal trend was somewhat similar to that for warmouths at Venard Lake. Bass stomachs collected in August contained very few items except fish and crayfish. That mayfly nymphs and midge (Dip- tera) larvae were important bass foods at Venard Lake was shown by the consist- ently large percentage of stomachs in which they occurred. Percentages were larger in spring and fall than in summer. Mayfly nymphs were found in at least as large a percentage of bass stomachs each season as was any other kind of food organism; they were found in a larger percentage of bass than of warmouth stomachs. The fall increase in utilization of mayfly nymphs by bass was not followed by a similar in- crease by warmouths. Nymphs of Siphlo- nurus sp. accounted for the fall increase in consumption of mayfly nymphs by bass; as many as 125 were found in each of sev- eral bass stomachs taken during Novem- ber. Only in the spring collections did the Vol: 27, Art. 1 August, 1957 nymphs of Caenis sp. occur in bass stom- achs as frequently as those of Siphlonurus ; Caenis was consistently the species of may- fly most abundantly taken by warmouths. The variation in utilization of these may- flies may have come from differences in their habitats: Siphlonurus is generally concentrated in deeper water than is Caenis and would be available to large- mouths feeding in open areas of the lake. Caenis is a shallow-water mayfly and would be taken by warmouths feeding along the banks and in shallow weed beds. The percentage of bass stomachs that contained damselflies (Zygoptera) and/or dragonflies (Anisoptera) decreased from spring to fall. A smaller percentage of warmouth than of largemouth stomachs contained nymphs of the Odonata. Large- mouth bass stomachs contained more adults and subimagoes of damselflies than did warmouth stomachs; in the June col- lection of bass stomachs, these forms out- numbered the nymphs taken. Larval and adult beetles (Coleoptera), bugs (Hemiptera), and bees and ants (Hymenoptera) occurred at peak abun- dance in bass stomachs during the summer, especially in June. The incidence of these insects was much greater in largemouth bass than in warmouths at Venard Lake. Larvae of the aquatic beetle Peltodytes Larimore: Lire History oF THE WARMOUTH 29 sp. were eaten in large numbers by a few largemouths; in June, 131 of the larvae were found in the stomach of one individ- ual and 115 in the stomach of another. Certainly the foods and feeding areas of warmouths and largemouth bass over- lapped in Venard Lake. However, even though largemouth bass and warmouths fed on the same kinds of organisms, and even though several of these organisms fol- lowed similar seasonal patterns of occur- rence in the stomachs of the two fishes, the competition was somewhat reduced by dif- ferences in feeding habits. Warmouths tended to consume the organisms on the soft bottoms, in shallow waters, and along the banks; largemouths fed more on the surface organisms and_ free-swimming forms in deeper or more open parts of the lake. General Conclusions on Food Habits Considerable differences have been ob- served in the contents of the stomachs of warmouths taken in small numbers at dif- ferent seasons or from widely separated localities, table 14. Forbes (1903:48-9) analyzed the stom- ach contents of warmouths collected at scattered localities in Illinois and neigh- boring states and considered the foods uti- Table 14.—Average of volume percentages for the food of warmouths studied by Forbes (1903), McCormick (1940), and Rice (1941) and for the food of warmouths of approximately the same sizes, and collected at about the same times of year, from Park Pond and Venard Lake. Forses (1903)|McCormick (1940)|Rice (1941) PresENT Stupy |PResENnT Stupy ILLINOIS Ree.troot Lake /ReEeLFroot LAKE|Park Ponp |VENARD LAKE AUTUMN SUMMER SUMMER SUMMER SUMMER Foop Item |6 FisH 69 Fisu 45 Fisu 59 Fisu \27 Fisu LencrTH, LenetH, IncHEs* |Leneru, INcHEs*|LeENcTH, IncHEs Lencru, INCHES INCHES 3.3-8.7 3.3-6.5 3.4-6.4 3.4-6.4 3+ (5.4 AVERAGE) (4.8 AVERAGE) |(4.7 AVERAGE) |(4.3 AVERAGE) (raydish: 6s... OR ett Re 46.38 99.5 29) 7 Dig he Th Entomosttaca.|........+-< 2.90 tr. 0.7 Os Mayflies...... 25 2.90 (age 2.9 Ey) Mamselfises S.J )e pfs ae ee 1.59 Weed 3.8 MAP ONtlieS ei-\\scss aes ase ms 10.87 52 23.8 Hemiptera. ... 18 7.68 Bot Br 0.3 ee oe Wiptera’ larvae!) sso: -. 6. 10.03 tr. 4.6 | 3.9 Miscellaneous | insects..... 10 5.07 eo V7i-3 (PS) he ere eae 47 7.94 20.5 5.9 Miscellaneous REUSE Csi Mae ices ote tt a a 4.64 tr. Bee 11-2 *Measurements here are equivalents of metric measurements given by author. 30 Ittinois NaturAL History SurvEY BULLETIN lized by fish of different sizes. The small warmouths in his study had eaten large numbers of Entomostraca, as had the small warmouths at Venard Lake and at Park Pond. In his six adult warmouths, table 14, crayfish were not represented, and fish made up a larger percentage of the food (47 per cent) than has been reported in other studies. Forbes related the espe- cially piscivorous habit of this species to the large size of its mouth. Dragonflies were noticeably absent in all the warmouth stomachs he examined. Data in studies made by McCormick (1940:73) and Rice (1941:26) at Reel- foot Lake, Tennessee, table 14, empha- sized the differences in foods utilized by a species in successive years, even at the same location and during the same season of the year. McCormick examined 69 warmouth stomachs which contained food and found that the average of volume per- centages of insects was 38.14 per cent. The comparable figure at Park Pond was 40.9 per cent. Crayfish were higher and fish were lower in the average of volume per- centages of warmouth food at Reelfoot Lake than at Park Pond. A year after Mc- Cormick’s study, Rice examined another series of warmouth stomachs from Reelfoot Lake. Of 45 stomachs which contained food, only 1 had food other than crayfish, table 14. For the periods of time covered by the studies cited in table 14, warmouths at both Venard Lake and Park Pond utilized a greater variety of food items than did warmouths in the other places listed, as is indicated by the percentages of “miscella- neous insects” and ‘“‘miscellaneous items.” Lewis & English (1949:321) examined the stomachs of 29 warmouths from Red Haw Hill Lake, Iowa. The fish were collected from April through July and ranged from 40 to 177 mm. in total length. In the 17 stomachs that contained food, “food items occurred as follows: 2- to 4-inch fish, 7; crayfish, 4; vegetable de- bris, 2; unidentified insect larvae, 4; leech, 1; dragon-fly naiad, 1; unidentified in- sects, 2; and snails, 1.” These figures probably refer to the number of stomachs in which each kind of food was found and not to the numbers of individual food items. The conclusion from this study was that ‘On a volumetric basis, fish and cray- Vol. 27, 7Art: 1 fish were the most important food items.” In a rather general statement involving five fishes, Black (1945: 463) mentioned that the warmouth in Shiner Lake, Indi- ana, hunts the northern mimic shiner, No- tropis volucellus volucellus (Cope), to the exclusion of almost all other food. At Park Pond, where many species of min- nows were present, small sunfish were more commonly taken by warmouths than were minnows. Hunt (1953:29) examined 25 small warmouths from the Tamiami Canal west of Miami, Florida. Twelve of these fish, ranging from 1.4 to 3.5 inches in total length, contained food material composed exclusively of animals, including the fol- lowing organisms: dragonfly, damselfly, and mayfly nymphs; dipteran larvae of va- rious kinds; a few scuds and large ostra- cods; and a large number of small shrimps, Palaemonetes paludosa. Huish (1947:15-6) examined 17 war- mouths from Lake Glendale (southern Illinois) during the summer of 1946. These fish, caught on artificial flies, ranged from 5.0 to 7.5 inches in total length. Of the 14 fish whose stomachs contained food, there were 3 with small fish, 1 with a tadpole, 3 with dragonfly nymphs, and 7 with crayfish. Fish, crayfish, and immature forms of aquatic insects comprised the important foods for most of the warmouths involved in the present study. Diets of the war- mouths in Park Pond were found to differ from the diets of the warmouths in Ven- ard Lake both as to the kinds and to the amounts of certain organisms eaten in va- rious seasons and by fish of different sizes. This study and others, some of which have been cited above, make it seem very un- likely that there is any specific diet or highly restricted food preference for this species. Food items of many kinds are ac- ceptable to the warmouth; this fish may feed upon any of those items that are read- ily available. REPRODUCTION Whether a fish population overcrowds its habitat is determined in part by its rate of reproduction—the development of sex products and the subsequent growth and survival of young fish. August, 1957 Development of Sex Products In interpreting the stages of develop- ment of sex products in a fish such as the warmouth, which spawns over a period of several months, one must keep in mind that all of the germ cells do not go through the cycle of maturation simultaneously ; instead, small groups of these cells mature at intervals and are spawned. This proc- ess is accompanied by a continuous recruit- ment of additional cells from the primor- dial stock. Thus, in a gonad in spawning condition, in addition to the fully matured sex products, there are other groups of cells representing earlier stages in the maturation process. Larimore: Lire History oF THE WARMOUTH 31 Annual Sexual Cycle.—Terms de- scriptive of the appearance of the fish gonad are useful for designating stages of devel- opment associated with seasons, table 15. Some of the terms used here are the same as those used by Bennett, Thompson, & Parr (1940:17). Partly because the gradual process of growth of germ cells varies among indi- viduals and partly because the develop- mental process is influenced by climatolog- ical conditions, the periods during which the various designated stages may be found overlap and are not exactly the same from year to year for either individual fish or for populations. Overlapping of develop- mental stages was evident in warmouths Table 15.—Appearance and significance of each stage in the development of warmouth gonads, related here to the seasonal occurrence of each stage in warmouths from Park Pond, 1948 and 1949. STAGE OF APPEARANCE OF GONADS SIGNIFICANCE OF STAGE SEASON DEVELOPMENT IN DEVELOPMENTAL OF or Gonaps Male Female Process STAGE Latent Clear pinkish white|Light amber, often _|A quiescent period; gonad|All year for fish to colorless; a with small red dots; |containing only primor- junder 3.5 inches; narrow translucent |lobelike in form dial germ cells July 1-April 15 strand and somewhat trans- for fish over 3.5 lucent inches Poorly Pinkish white, Pinkish orange to Initial maturation March 1—May 1 developed |opaque, becoming _ [light yellow; of sex products ribbon-like slightly granular and somewhat enlarged Well White, opaque; Bright yellow; Advanced development |April 15—June 1 developed |ribbon-like, with very granular and of germ cells; heavy wavy margins fully distended, yolk accumulation in with opaque eggs ova Spawning Appears as in Appears as in Completed germ cells May 15—August condition jpreceding stage but |preceding stage but _|free in gonad, ready 15 flowing milt when |flowing eggs when to be discharged gently pressed gently pressed Partly White to gray; more} Yellow to orange, No germ cells free in June 1—August 20 spent nearly flat than in |/with congested gonad, but a considerable spawning condition |blood vessels; stock of well-developed less distended than ova and sperm remain- in spawning condition |ing Spent Muddy white, Reddish-orange, Remaining matured June 15—Septem- becoming smaller and less distended flaccid, with congested blood vessels germ cells resorbed; ber 1 gonad reorganizing, but effect of spawning still evident 32 collected from Park Pond during the spawning season of 1949. These fish were divided into two size groups established on the basis of differences in maturation: in the first group were “large” warmouths, those of more than 5.4 inches total length; in the second group were “small” warmouths, those between 3.5 and 5.4 MAY JUNE JULY 100 80 60 40 PER CENT 20 IN. MALES 3.5-5.4 MAY JUNE JULY PER CENT FEMALES 3.5-54 IN. | LATENT [__] spawninG CONDITION Intrnors NATURAL History SurvEY BULLETIN 100 Vol. 27, Art. 1 2. All the “large” individuals took part in spawning activities, whereas a consid- erable proportion of the specimens be- tween 3.5 and 5.4 inches remained imma- ture during the entire nesting season. 3. The ‘‘small” warmouths recovered more quickly from the effects of spawning than did the “large” ones; all of the MAY JUNE JULY 80 60 40 20 IN. MAY JUNE JULY QV? o, o, : S32 IN. POORLY TO WELL DEVELOPED EY PARTLY SPENT SPENT Fig. 8.—Percentage of warmouth males and females (two size groups) in each of five stages of sexual development during May, June, and July. These warmouths were collected from Park Pond, May 13 to August 1, 1949. inches total length. Warmouths shorter than 3.5 inches were eliminated from this part of the study because they would not mature in the then current season. The following generalizations may be made re- garding the season of greatest sexual ac- tivity of the warmouth, fig. 8: 1. The “large’’ warmouths (over 5.4 inches total length) attained spawning condition sooner and spawned over a longer period than did the “small” fish (3.5-5.4 inches total length). “small”? warmouths were in a latent condi- tion by August 1, whereas among the larger fish only 14 per cent of the males and 33 per cent of the females possessed gonads that had become reorganized by that date. 4. The males ripened slightly earlier in the season than did the females and re- mained sexually active somewhat longer. In the smaller size group (3.5—5.4 inches total length), a considerable propor- tion of both males and females had latent : : August, 1957 gonads after the first week in May, fig. 8. The continuous rise in percentage of latent gonads found in this size group during the nesting season may have resulted from (1) rapid reorganization of the gonads of early spawners, (2) failure of some small indi- viduals to spawn and prompt return of these individuals to the latent condition, (3) growth of fish during May, June, and July, which resulted in the recruitment of some sexually undeveloped fish into the 3.5—5.4-inch group and the loss of some sexually mature fish from this group to the size group beyond 5.4 inches, and/or (4) inadequacy of collections and their failure to represent true proportions of individuals in the various developmental stages. Field observations showed that sexually mature females do not have free ova (which can be forced out by gentle pres- sure on their sides) except immediately before and during the spawning act, whereas sexually mature males may be in- duced to extrude milt during much of the spawning season. These observations may explain the fact that many more males than females were classed as ripe. “The scarcity of small males that were classed as completely spent was due probably to the dithculty of separating partly spent from completely spent individuals in the small sizes. By expressing the weight of gonads at regular intervals through the year as per cent of body weight, one can follow the increase and diminution in size of the sex glands and fit the observed spawning con- dition of fish into the annual sexual cycle (James 1946 and others). Statistics on monthly gonad weight—body weight rela- tionships for warmouths in Illinois were based on 222 females and 260 males col- lected in Park Pond from early October, 1948, to early September, 1949, fig. 9. The fish were divided into three size groups: (1) less than 3.5 inches total length, (2) 3.5—5.4 inches total length, (3) more than 5.4 inches total length. Most of the warmouths of 3.5 inches and longer total length were sexually mature; most below this length were sexually im- mature. During the period beginning with Sep- tember and ending with March, there was no appreciable change in gonad weights among warmouths. Soon after the initial LarImorE: Lire History oF THE WARMOUTH 33 rise ‘of water temperatures in March, the gonads in warmouths longer than 3.5 inches began to enlarge, and they increased rapidly in weight during April and May. The ratio of gonad weight to body weight increased most rapidly in the large war- mouths (over 5.4 inches); males in this group showed their greatest average gonad weight in May and females showed their greatest average gonad weight early in June. The ratio of gonad weight to body weight for both male and female war- mouths between 3.5 and 5.4 inches in length averaged highest the first week in June. Soon afterwards, however, the ratio of gonad weight to body weight declined rapidly for females in the two larger size groups. Among males of both groups, there was a drop in weight of testes, but the males remained sexually developed later in the season than did females. The ratio of gonad weight to body weight may be at a minimum immediately following cessation of sexual activity, but it may in- crease slightly with reorganization of the gonads. Evidence from the cycle of changes in the ratio of gonad weight to body weight lends support to the conclusion previously drawn that large warmouths mature ear- lier in the season than do small ones and also remain active reproductively over a longer period. In this series of specimens, initial ripening of the sex products oc- curred during the second week in May, 1949, fig. 9. At the time other warmouths were spawning, warmouths under 3.5 inches total length showed no increase in the rela- tive weight of the gonads; in fact, an apparent decrease took place. This decline was probably associated with an improve- ment in condition (an increase in the body weight) of the smaller fish during May, June, and July. The irregularities that appeared during winter months in gonad weight-body weight relationships of fe- males in the two smallest length groups, fig. 9, were attributed to changes in body weight rather than to changes in gonad weight; these irregularities corresponded to changes in the coefficient of condition, agg WE Increasing length of day and rising tem- peratures associated with spring are known to stimulate gonad development in fishes. 34 ILtLino1is NATURAL History SURVEY BULLETIN In 1949, the ratio of average gonad weight to average body weight of Park Pond warmouths began increasing early in March and roughly corresponded to an up- swing in mean monthly air temperatures above 40 degrees F. (United States ——. FISH UNDER™ 3.5 IN. FISH 3.5-5.4 IN. FISH OVER 54 IN. INTERPOLATION GONAD WEIGHT 7 BODY WEIGHT, PER CENT Vol. 27, Art. 1 Weather Bureau 1948-1949, Danville Station). Spawning was actually initiated at water temperatures (12 inches deep) of about 70 degrees F. Low ratios of gonad weight to body weight for the summer months of July and August, 1949, indi- 90 80 WATER TEMPERATURE ed 70 60 50 im = 40 ta ac = ps 30 w a = uJ | ae 20 10 (@) OCT NOV DEC JAN FEB MAR APR MAY JUN JUL AUG SEP 1948 1949 Fig. 9—Curves illustrating the relationships of gonad weight to body weight (the per cent the gonad weight is of the body weight) for male and female warmouths of three size groups collected from Park Pond, early October, 1948, through early September, 1949, and water tem- peratures (degrees F.) taken with a mercury thermometer 12 inches below the water surface. August, 1957 cated that most of the spawning was com- pleted by early July. Information obtained from collections of warmouths made the previous summer suggested that the spawn- ing season in 1949 may have been shorter than in most years. Fecundity.— Probably one of the more dificult problems in studying the repro- duction of a fish is how to estimate the total number of ova developed in a season by an individual female. The problem is especially complex in a fish that, like the warmouth, spawns an indefinite number of times over a rather long period and that contains large numbers of eggs too small to be counted without some magnification. Usually an extended period of sexual ac- tivity in fish is associated with a continu- ous maturation of eggs and sperm, so that sex products may ripen and be discharged at frequent intervals during the spawning season. Thus, at almost any time during the spawning season, in the ovary are sey- eral sizes of ova representing various stages of development from primordial germ cells to yolk-laden eggs ready for spawning. The egg-counting problem presented by the warmouth was not solved by any of the methods previously reported for de- termining the number of eggs in fish ova- ries. The method used—based on the dry weight of the egg mass in an ovary—was developed as an efficient way to estimate the numbers of ova of various sizes. The first step involved measuring several hun- dred ova and sorting them into seven size groups. A low power binocular microscope (18) equipped with an ocular microm- eter was used to measure each of the sev- eral hundred ova to the nearest 0.05 mm. The seven size groups were as follows: I, 0.15-0.30 mm.; II, 0.35-0.45 mm.; III, 0.50-0.60 mm.; IV, 0.65-0.75 mm.; V, 0.80-0.90 mm.; VI, 0.95-1.05 mm.; and VII, 1.10 mm. and over. Group I in- cluded most small ova except the undiffer- entiated germ cells in the ovigerous lam- ellae. All ova diameters were measured as the ova appeared at random on the horizontal scale of the ocular micrometer. Clark (1925:5), in using a similar system of measurement, proved this was a reliable method of measuring eggs that were not spherical. The ova were separated into the LarimoreE: Lire History oF THE WARMOUTH 35 various size groups as they were measured. Twenty ova belonging to each size group were then placed in a platinum crucible of known weight and put in a drying oven at 45 degrees C. After remaining in the dry- ing oven for 48 hours, the eggs, in the crucible, were moved to a desiccator, where they were left until repeated weighings showed no changes in weight. (It is now believed that the use of a desiccator was not necessary.) Each sample was weighed to the nearest 0.01 mg.; through calcula- tions, the tentative average dried weight for ova in each of the various samples was determined. For each size group, five ad- ditional samples of 20 eggs each were dried and weighed before a final average dried weight was determined. The average dried weight determined for eggs in each size group was assumed to be the same as the average dried weight for eggs in a similar size group in other ovaries. Steps in processing each ovary for which a calculation of egg numbers was desired were as follows: (1) The connective tissue sheath surrounding the ovary was removed, and the eggs were teased apart; (2) a ran- dom sample of several hundred eggs was taken from the total mass of eggs in the ovary; the eggs in the sample were meas- ured individually and separated into size groups, and the percentage of eggs in each size group was determined; (3) the mass of eggs remaining was washed, placed in a drying oven at 45 degrees C. for 48 hours, moved to a desiccator, and kept there until repeated weighings showed no changes of weight. Steps in calculating the total number of eggs in an ovary were as follows: 1. The average weight (dry) deter- mined for eggs of each size group was mul- tiplied by the percentage of eggs of the random sample in that size group. The products from the calculations for all the size groups were added and the sum mul- tiplied by 100 to give the calculated dry weight of 100 representative eggs of the sample. 2. The weight of the dried eggs (ex- clusive of eggs in the random sample) was divided by the calculated dry weight of 100 representative eggs, as determined from the random sample, and the result- ing quotient was multiplied by 100; to this product was added the number of eggs 36 Ittino1is NATURAL History SURVEY BULLETIN in the random sample. The sum of these numbers was the calculated total number of eggs in the ovary. The calculated number of eggs in each size group in the ovary was determined by multiplying the calculated total number of eggs in the ovary by the percentage of the random sample represented by the size group. A modification of the dry-weight method described above, and one that did not re- quire the initial work of determining the average dried weight of eggs of each size group was as follows: After the eggs were teased apart and the connective tissue removed, (1) eggs in a random sample were counted (and measured if there was interest in size groupings), dried, and weighed, (2) the eggs remaining were dried and weighed, and (3) the total num- ber of eggs was then calculated on the basis of the total dried weight of all eggs im the ovary including those in the ran- dom sample. This method was similar to that used by Katz & Erickson (1950176) for estimating fecundity of herrings, in which only one size group of eggs was involved. When the numbers of ova in only a few ovaries are to be calculated, this modified dry-weight procedure is faster than the method first described. However, once the average dried weight of ova of each size group has been determined, the first method requires less work and is faster be- cause the sample ova that are measured, sorted, and counted do not have to be dried and weighed. Ovaries for which estimates of num- bers of eggs were made—38 ovaries from Park Pond and 10 from Venard Lake— had been divided into four groups: those taken from Park Pond warmouths in (1) January and March, (2) April, May, and June, (3) July and August, and (4) those taken from Venard Lake warmouths, May 25, 1949. In these ovaries, there was a pos- itive correlation between estimated num- bers of eggs in individual fish and total length of fish. Coefficient of correlation values ranged from 0.64 to 0.98. Seasonal variations in the number of eggs in warmouth ovaries were considera- ble. There was a marked increase in num- ber of eggs per ovary from late winter to the peak of the spawning period, fig. 10. Vol. 27, Art. 1 Immediately after the peak of spawning ac- tivities, the number of eggs per ovary was considerably reduced. At that time, the correlation between number of eggs and size of fish was lowest; this low correla- tion was due to the depleted condition of the ovaries, some of them being partly spent, some entirely spent, and others part- ly recovered. Females showing recovery from spawning contained more eggs than did the spent fish. During the fall and winter months, the number of eggs per ovary increased gradually; the final and greatest increases took place in the spring when groups of small eggs were adding yolk and undergoing final maturation. Fish of comparable sizes in different bodies of water did not produce comparable numbers of eggs. For example, a Venard Lake female, 5.3 inches in length, con- tained 40,400 eggs, whereas a female of this length from Park Pond contained only 12,500 eggs, table 16. This large differ- ence may be explained in part by differ- ences in environmental stresses upon these warmouth populations resulting from (1) a rapidly expanding population in Venard Lake in 1947 and 1948 in contrast to an older and more stable population in Park Pond, (2) a greater concentration of fish in Park Pond than in Venard Lake, and (3) a higher incidence of parasitic infesta- tion in the more concentrated population of fish. Venard Lake was stocked in the spring of 1947, and the fish population expanded rapidly during the 1947 and 1948 growing seasons. Although the population probably had attained its maximum size by the time ovaries were collected for egg counts in 1949, the rapid expansion of the popula- tion in the preceding two seasons may have been at least partly responsible for the fact that the number of ova per female war- mouth was greater for fish collected from Venard Lake than for those from Park Pond. Park Pond had a higher population den- sity of fish other than warmouths than had Venard Lake, which had only warmouths and largemouth bass. Where many fish are concentrated within a limited volume of water, there may be severe competition for food and space among members of this population. The smaller number of eggs per warmouth in Park Pond may have been ugust, 1957 Larimore: Lire History oF THE WARMOUTH 37 64 VENARD LAKE o—— MAY, r=.88 it PARK POND JAN-MAR r=.98 a—— APR-JUN r=.97 A--— JUL-AUG r=.64 48 40 AP riwvwvrivy 32 24 WUNVWDOLMN Wi Wve tVIAu 2.0 3.0 4.0 5.0 6.0 7.0 TOTAL LENGTH OF FISH, INCHES Fig. 10—Estimated number of ova from warmouths of various total lengths in collections from Park Pond (January-March, April-June, and July-August) and Venard Lake (May), 1949. Scattergram, regression line, and coeficient of correlation (r) are given for each collec- tion group. Elevations of the regression lines indicate seasonal changes in numbers of ova in three groups of Park Pond warmouths and also indicate that females from Venard Lake pro- duced more ova than did females of similar sizes from Park Pond. Each graphic symbol repre- sents one female from which the number of ova was estimated. 38 Inutinois NarurAL History SurvEY BULLETIN Vol. 27, Art. 1 associated with interspecific competition were in much better body condition (aver- among several species rather than intra- age of coefficient of condition 82.2) than specific competition among warmouths. were Park Pond females of similar sizes Of the warmouths for which ova counts taken at about the same time (average of were made, the females from Venard Lake coefficient of condition 73.8). This differ- Table 16.—Estimated numbers of ova in 38 warmouths from Park Pond and 10 from Venard Lake, 1949, arranged according to seasons and in order of increasing total length of fish. ’ EstTIMATED LENGTH OF WEIGHT OF DaTeE OF PLACE AND TIME Fisu, IncHEs FisH, Pounps CoLLECTION Bie is at Park Pond, 4.4 0.06 March 2 8,100 January-March 4.7 0.07 March 2 10,200 Sal 0.09 March 2 11,200 Dye 0.11 March 2 12,300 523 0.11 March 2 12,500 Eee 0.13 January 8 15,600 6.4 0.21 January 8 24,300 6.6 0.24 January 8 23,400 Park Pond, 3.5 0.03 May 23 4,500 April-June 3.6 0.03 April 9 6,200 4.1 0.05 May 13 10,200 4.3 0.05 April 9 9,800 4.6 0.06 May 14 11,200 4.8 0.09 May 13 11,200 510 0.09 April 7 17,700 5A 0.10 May 13 11,600 sit 0.10 May 14 12,000 5.4 0.12 May 13 13,900 5.5 0.13 May 13 15,500 526 0.12 June 10 17,900 5.6 0.14 April 9 22,200 St 0.15 June 10 18,300 5.8 0.15 June 10 26,000 5.8 0.15 May 13 25,600 5.9 0.16 May 13 21,200 6.0 0.18 May 14 25,500 6.1 0.18 May 13 30,400 6.2 0.17 May 14 23,700 6.4 0.20 June 3 31,900 6.9 0.28 May 14 32,700 cai 0.29 June 10 37,500 Park Pond, 5S 0.12 August 1 11,000 July—August 5.6 0.14 August 15 15,100 ae | 0.15 July 5 13, 100* 6.2 0.20 July 8 16,200 6.3 0.16 July 5 11,300** 6.6 0.24 August 15 19,800 6.7 0.24 August 1 16,100 Venard Lake, Ba 0.04 May 25 17,200 May 4.1 0.06 May 25 31,400 4.2 0.06 May 25 30,200 4.3 0.06 May 25 26,000 4.4 0.07 May 25 28,200 4.4 0.07 May 25 29,000 4.6 0.08 May 25 31,600 ae! 0.11 May 25 57,000 S50 0.12 May 25 40,400 5.4 0.14 May 25 63,200 *Two plerocercoids of Proteocephalus. **Four plerocercoids of Proteocephalus. August, 1957 =nce in body condition indicated that the Venard Lake females had a greater amount yf reserve energy, which was available ror the production of eggs. Functions of the gonads of warmouths may be disturbed by internal parasites. Iwo ovaries in the series examined were yarasitized by plerocercoid tapeworms and -ontained fewer ova than expected, table '6. However, in both Park Pond and Ven- ird Lake there was such a high correlation yetween egg production and length of fish, ‘egardless of differences in parasitic infes- ations, that it does not seem possible that yarasites greatly influenced egg production n these populations. Fecundity in warmouths may be re- luced by lack of suitable nesting space, by yvercrowding of the population, unfavor- ible weather conditions, or other circum- tances which limit spawning opportunities ind result in large numbers of mature eggs yeing retained and resorbed in the ovaries. “xamination of ovaries from warmouths aken from Park Pond during the middle ind last of June, 1949, revealed that only mall percentages of mature eggs were yresent in these fish and that some of these zgs were being resorbed, indicating that \ot all the ova produced were actually dis- harged. It was found that the spawning eriod for warmouths was generally horter in this water area than in other vater areas under observation in I[Ilinois. Seasonal Development of Ova.— Jevelopment of warmouth ova through he seasons was observed in the fish col- ected from Park Pond, figs. 11 and 12. [he development was followed by assign- ng the ova collected at various times to he size groups defined on page 35. The easonal occurrence of eggs in these size ‘roups was as follows: 1. From January to early April, ova- ies contained only the smallest eggs (size roup I, 0.15—0.30 mm. diameter). 2. During the second week in April, the va began to increase in size; some ova vere in group II. 3. By the middle of May, in some fish wo-thirds of the eggs were of the smallest ize, or size group I, and small numbers of ggs were in size groups II, III, IV, and /. In other fish only one-third of the eggs vere in size group I, and group VI, as vell as groups II, III, IV, and V, was LarimMoreE: Lire History oF THE WARMOUTH 39 represented. In still other fish, there were relatively more eggs in groups V and VI than in groups II, III, and IV. 4. Toward the end of May, all of the size groups of ova were well represented, and some of the eggs appeared to be ripe. 5. By the end of the first 2 weeks of June, the ovaries of all the mature fish had discharged most of the largest eggs. Some of the fish appeared to be preparing for a final spawn; about one-fourth of their eggs were in size group V and only low per- centages in groups II, III, and IV. Other fish appeared to have completed spawning, and their ovaries appeared to have begun reorganizing, as small eggs again com- prised three-fourths of the ova present. 6. On completion of spawning in July or early August, ovaries contained many pulpy eggs that were undergoing rapid re- sorption; the only other eggs present were those of group I. The ovigerous lamellae were poorly organized, showing no recov- ery from the production and crowding of large volumes of mature eggs. 7. By mid-August, ovaries were fully reorganized; the well-arranged ovigerous lamellae contained many small ova which comprised a part of the egg-stock for the next season. Prespawning Activities Nest building and spawning activities of the centrarchids probably have been stud- ied more thoroughly than the spawning be- havior of any other family of fishes (Bre- der 1936 and others). Although the repro- ductive behavior of the warmouth is much like that of other sunfishes, it may differ in the location and construction of nests, recognition of sex, courtship, care of eggs and larvae, and spawning schedule. Location and Construction of Nests.—Warmouths appear to exercise selection in their choice of nesting sites. Both available bottom materials and cover influence this selection. In Venard Lake, where nesting was easily observed, the fol- lowing types of bottom were available: loose silt, silt containing sticks and leaves, rubble, rubble covered with a thin layer of silt, sand with loose silt, and clean sand. No nests were found on clean sand (such as is often selected by bluegills and pump- kinseeds), and the only nests seen on loose 40 silt were closely associated with tree roots or mats of submerged plants. Even though the Venard Lake warmouths used each of the bottom types (except sand) as nesting sites, they showed some preference for rub- ble lightly covered with silt and detritus. The warmouths at Venard Lake were not so consistent in nesting on a particular kind of bottom as they were in selecting a spot near a stump, root, rock, clump of 100 ~J on JAN. 8 3 Fish | MARCH 2 5 Fish APRIL 9 3 Fish oO oO Mm ol 5 PER CENT OF TOTAL NUMBER OF OVA ol oO 25 III seme | ee I ILLiNois NATuRAL History SURVEY BULLETIN Vol. 27, Art. 1 vegetation, or some similar object. This habitual preference for a location adjacent to a stationary object may account for the lack of nests on the clean sand bottom in Venard Lake. Nests were never found on ~ an area of bottom completely exposed, such as the bluegill usually selects. In labora-— tory aquariums, the locations most often — used by warmouths for nesting were near the vertical drain pipes. APRIL 9 Fish V Vil | I SIZE GROUP OF OVA Fig. 11.—Percentage of total number of ova in each size group of ova found in warmouths collected from Park Pond and Venard Lake, January 8 to May 25, 1949. August, 1957 In Park Pond, warmouths nested among weed masses, stumps, roots, and brush; they nested in areas where the water was less than 4 feet deep and were most fre- quently seen where the shale and rubble spread out at the ends of the old spoil banks or had filled in the back portions of the flooded strip channels. ‘They were not seen nesting where the banks were steep and sloped off quickly into deep water. 100 ~J ol oO oO ine) ol JUNE 10 3 Fish Pen UENT OF 1ClBL~ NUMBER OF (OVA 25 | ti Mia Mies | Il LarimorE: Lire History oF THE WARMOUTH 41 Warmouths build nests within a wide range of water depths, and consequently nest locations vary in their distances from shore. Earlier observers of warmouths re- corded a variety of water depths selected : 6 to 10 inches (Richardson 1913: 412) ; mostly 2 to 10 inches (Carr 1940:109) ; 3 feet (Hubbs 1919: 144); 2 or 3 feet (Toole 1946: 33). In Venard Lake, the depths of water over warmouth nests that JULY 5,8 3 Fish AUG. 1,15 4 Fish V Vil | HI V SIZE GROUP OF OVA Fig. 12—Percentage of total number of ova in each size group of ova found in war- mouths collected from Park Pond and Venard Lake, May 25 to August 15, 1949. 42 were found ranged from 6 to 60 inches. Most of the nests were covered with 2 to 2.5 feet of water; nests in deeper water were more difficult to locate and may have been more common than counts showed. The limited areas of shallow water or the high transparency of the water in Venard Lake might account for the comparatively great depths at which nests were found in this body of water. Reports of some observers indicate that the warmouth is gregarious in its nesting habits, forming colonies of nests (Richard- son 1913:412; Carr 1940:110). It seems probable, however, that colony formation is a result of restricted nesting habitat. Observations of Carr (1940:109) in Flor- ida and of the author in Il]linois support the assumption that the reason warmouth nests are sometimes found close to each other is that the fish are tolerant of each other rather than gregarious in their habits. The warmouth colony studied by Carr was formed on what may have been the only bottom of suitable depth not cov- ered with ooze. In Venard Lake, in May and June, 1947, nests were scattered in shallow water along the shore line with no indication of colonization. Three nests within a linear distance of + yards were the only ones that were found very close together. Nest construction by warmouths in lab- oratory aquariums was observed many times in the course of the study reported here. As in other sunfishes, the male ex- cavates the nest. Violent sweeping motions of the tail clear the loose debris away from the selected spot and produce a shallow, irregular concavity. The male begins each sweeping movement by approaching the nesting spot with his nose low and close to the bottom. As he enters the nest site, he turns abruptly upward, giving three or four violent sweeps with his tail while bal- ancing in an almost vertical position and checking his forward motion with his pec- toral fins. The loose material in the nest area is stirred up, and much of it settles outside the spot being cleared. The size and neatness of the nest depend to some extent on the amount of time the male spends in its construction. Many nests in natural waters are rather shapeless oval de- pressions of 4 by 8 inches from which loose silt has been cleared. The male may con- Ituinors NaturAL History SurvEY BULLETIN Vol. 27, Art. 1 tinue to improve the nest if a female is not immediately available for spawning. One warmouth male nesting in an aquarium worked on his nest until it was a beauti- fully symmetrical depression 18 inches in diameter and 5 inches deep. Though most warmouth males under natural conditions spend no more than a few hours in clear- ing small nesting spots, the male in the aquarium spent a week working on his nest while waiting for the female that was present to become ripe. A mature female warmouth isolated in an aquarium during the breeding season constructed a shallow nest; her attach- ment to the nest was much weaker than that characteristic for a male. Preliminary Courtship.—The pre- liminary courtship phase of warmouth nesting was observed by the author only in laboratory aquariums. Normally it ap- peared as an aggressive threat to other males, serving to drive them away, and as a persuasive gesture to females in spawn- ing condition. During the first week in May, 1947, three unripe warmouths were placed in ee each of four aquariums previously filled — with water and supplied with a layer of sand and gravel. By the second day, some — of these fish had selected favorite corners and were accepting food. Two of the three — fish in each tank soon began constructing nests and making advances at the third fish. On the basis of behavior, only the nest-building warmouths appeared to be males; the third fish in each of the tanks showed no interest in nesting and appar- — ently was being courted by the aggressive males. Courtship in each tank progressed — to the act of driving the nonnest-building warmouth into the nest depression and go- ing through motions of spawning. Vivid spawning colors (discussed in the follow- ing section) were displayed by only the ag- gressive males; no color changes were shown by the fish that were being courted. — After these courtship activities had con- tinued for several days, the fish were ex- amined. Several had become ripe since be- ing put in the aquariums and were flowing milt. Dissection of the nonaggressive, non- nest-building fish revealed that they, too, were males, although not in advanced stages of development, as were the aggres- sive males. August, 1957 These initial observations of spawning suggest that (1) warmouth males begin construction of the nests in the absence of females and well before their testes are ripe; (2) sex recognition among war- mouths is based on behavior and response to courting; and (3) in a small group of warmouths, during the breeding season some individuals assume dominance over less aggressive fish. When a female that is not yet ready to spawn is placed in a tank with a nesting male, she is charged, nipped, and driven to the surface. She remains quiet and retir- ing, ignoring as much as possible the male’s advances. Being unable to escape the male in an aquarium, she may finally be killed by his continued aggression. Under nat- ural conditions, the female does not become exposed to the unavoidable advances of the nesting male before she is ready to spawn. Spawning In the warmouth, the mating act, which includes the deposition and fertilization of eggs, requires the simultaneous ripening ot sex products and synchronization of be- havioral attitudes in a male and female. Many environmental conditions, as well as the state of maturity of the fish, affect the spawning process. Size and Age at Sexual Maturity. —The attainment of sexual maturity in fishes is influenced by both age and size. In the warmouth, size seems to be more important than age in determining when a fish attains maturity. However, there is considerable variation among warmouths in the size (and age) at which maturity is reached. As might be expected, this vari- ation is greater between fish of different populations than among fish within a sin- gle population. Sexual maturity is attained by war- mouths when the fish are between 3 and 4 inches in length. In Venard Lake, both males and females matured at 1 year of age and at lengths between 3.1 and 3.4 inches. In Park Pond, warmouths did not mature until they were 2 years old and at least 3.5 inches in length. Thus, at the time the fish became sexually mature in Park Pond, they were somewhat larger than the sexually mature 1-year-old fish in Larimore: Lire History oF THE WARMOUTH 43 Venard Lake. Hile (1941:319) found for the rock bass that rapid growth appears to be correlated with an early attainment of sexual maturity. Nesting Season.—The observed nest- ing season for the warmouth in central Illinois begins during the second week in May, reaches its peak early in June, starts to decline after the first of July, but often extends well into August. The length of the nesting season differs among different populations of warmouths in different lakes and probably varies considerably from year to year. The length of the season varies also with the size of the fish; large war- mouths spawn over a longer period than do small ones, fig. 8. Although the exact length of the spawn- ing season is difficult to determine for an individual fish, studies of gonads have shown that a fish may spawn several times during a summer. In ‘Texas, ‘Toole (1946:33) reported, “One pair of these fish was observed to spawn three different times during one year from April to Octo- ber.” At the Natural History Survey lab- oratory, two females that spawned early in June, 1948, were examined 2 weeks later and were found to have well-devel- oped ova. These fish were not spent after the one spawning period and would un- doubtedly have produced more ripe eggs during the same season. Warmouths that were collected in July, 1948, and that pre- sumably had spawned at least once, were placed in a small pond on the following August 10; they produced a good brood of young in the pond that season. Deposition and Fertilization of Eggs.—Only when a female is ready to lay her eggs will she allow a male to guide her to the nest for spawning. In getting the female to the nest, the male assumes a very aggressive attitude, approaching her with his opercles widely spread and _ his mouth open. ‘The body of such a courting male becomes bright yellow in color and his eyes become blood red. The adjust- ment to these colors is very rapid, requir- ing only 5 to 10 seconds. If the female is ready to spawn, she is easily directed to- ward the nest, and spawning soon follows. The number of females contributing to the complement of eggs in a nest may de- pend upon how many females are ripe and available to the male. It is probably not 44 Ittinors NAturRAL History SuRVEY BULLETIN uncommon for more than one female to spawn in a single nest, as has been observed for other centrarchids. That such polyg- amy seldom occurs after the male assumes close guardianship of the eggs is indicated by the fact that freshly laid eggs are not commonly found in nests containing eggs in advanced stages of development. In a laboratory aquarium, however, a male guarding yolk-sac fry brought a female to the nest and proceeded with spawning ac-- tivities. One female observed in a large aquarium in which two males had nests only 10 inches apart alternated between the two nests during a continuous spawning se- quence. During an hour of spawning ac- tivity, the female spawned with both males. When she was in one nest, the male in the other nest showed no concern for her; he would inspect the newly depos- ited eggs, stir the nest with his tail, and wait for the female to again approach his nest. The female spawned almost contin- uously for 40 minutes and for another 20 minutes at brief intervals and less vig- orously. When spawning was finished, the female was temporarily removed from the ee c - ae PE oe oe _ a a: ‘3 a ir : Ban ge Fig. 13—Warmouths spawning in an aquarium. The light-colored fish is the male; the darker fish below and slightly on her side is the female. Vol. 27, Art. 1 aquarium; gentle pressure on the sides of this female did not cause the discharge of any eggs. On entering the nest site, both male and female begin to circle, the female being nearer the center of the nest, slightly on her side and somewhat beneath the male, — fig. 13. As they circle inside the nest, the female works her jaws three or four times and suddenly jerks her body violently, giv- ing the male a sharp thump on the side. Each time the female jerks, she extrudes about 20 eggs. The thump she gives the male probably stimulates a discharge of sperm, although no milt was ever seen — coming from the genital pore. After cir- cling the nest several times, the female interrupts the activities and leaves the nest site. The male usually follows her a short distance but returns quickly to the nest to assume guardianship. At this point in the spawning activity, males often have — been observed to fan the nest with sweep- — ing motions of the tail in a manner similar © to that exhibited when nest building. Spawning activities like those observed in aquariums were carefully watched in Venard Lake. In nature, when a female August, 1957 is ready to spawn, she makes her appear- ance near a nest and accepts the advances of the male. After a few spawning turns inside the nest, she retires, usually to a clump of weeds several yards away. The ' male remains over the nest for a few min- utes before again making advances toward the female. This procedure is repeated un- til the female has discharged her ripe eggs. With spawning completed, the female swims away, and the male settles down quietly to protect and fan the eggs. History of Embryos and Larvae When the warmouth starts its life and development, it is confronted by greater stresses of physical and biological factors than it will face at any other time during its life. “Temperature changes or tempera- ture extremes, disease and predation, and dependence on the constant protection of a parent fish, which may at the same time be exposed to many dangers, result in high losses in the period of early development of the warmouth. Development of Embryos.—Four groups of warmouth eggs, 10 in each group, were artificially inseminated in or- der to observe the gross development of the embryos and the exact length of the incu: bation period. The following account in- cludes the time sequence of certain easily discerned stages of development at tem- peratures between 25.0 and 26.4 degrees C. Within this temperature range, the average developmental period of the 40 eggs was 34 hours and 3() minutes and the interval between hatching of the first egg and hatching of the last was 2 hours and 40 minutes. ; When eggs and sperm were mixed in a petri dish and then immediately flooded with water, a high percentage of the eggs became fertilized. The inseminated eggs measured ().95 to 1.03 mm. in their great- est diameters during their first and second minutes in water. These measurements are slightly below those of the largest ova taken from preserved ovaries. Differences in size measurements between preserved and live ova may have been due to differ- ences in shapes: irregular shapes of the ova preserved intact in the ovaries and almost spherical forms of the live ova in water. Each of the live eggs, translucent and light Larimore: Lire History oF THE WARMOUTH 45 amber in color, contained a single, dark amber oil droplet 0.35 mm. in diameter. Within 3 minutes after an egg was im- pregnated by a sperm cell, a thin perivitel- line space could be seen between the outer membrane (chorion) and the egg cell proper. Thirty minutes later, a blastodisc was evident as a slightly raised cap, giving the egg a somewhat oval appearance. The first division of the blastodisc occurred 43 minutes after impregnation. Each blasto- mere then measured 0.4 mm. across. The second, third, and fourth divisions took place at 60, 75, and 90 minutes, respec- tively. The resulting group of blastomeres appeared whitish, the yolk was very pale yellow, and the oil droplet remained dark amber in color. After 2 hours and 15 minutes, the blas- tomeres formed an oval-shaped mass at one end of the yolk. The segmentation cavity was formed beneath this mass, and at 2 hours and 30 minutes the blastoderm be- gan growing down over the yolk mass. The blastoderm had grown over two- thirds of the yolk mass within about 11 hours after impregnation, and a thickened band of cells at the margin of the blasto- derm had appeared as the germ ring. About an hour later (12 hours and 15 minutes after impregnation), the blastoderm cov- ered all but a small plug of yolk, which contained the oil droplet. The first differ- entiation among the dividing cells was visi- ble in the live egg after 14 hours and 15 minutes. A groove extended around the ege from a patch of opaque cells near where the yolk plug and oil droplet en- tered the blastoderm. This groove, formed by the neural plate and neural folds, be- came quite distinct during the following hour (15 hours and 10 minutes after im- pregnation). After 16 hours and 30 minutes, the primordial form of the embryo was de- fined. The ensuing process of organ for- mation, however, could not be discerned. Movement of the embryo was first ob- served 25 hours after impregnation. The first egg hatched 33 hours and 20 minutes after impregnation. All eggs had hatched by the end of the following 2 hours and 40 minutes (36 hours after im- pregnation). Fry emerging from the eggs early during the hatching period were smaller (2.30-2.60 mm. in total length) ‘WW O'ZT ‘BAreyysod ‘y f*ww gg ‘eArepysod ‘7 ‘ww 9*/ ‘eAreijsod ‘gq ‘plo skep + “wu ¢°¢ ‘eAre]ysod ‘7) {pjo sinoy gp “wu gp ‘eArejoid ‘g {Buryoyey 1a3ze uoos “wu 4°¢ ‘eAIvjord ‘py :aBe3s [eArepysod ySnory) Suryoey worz syynowse MA— fT] “$I : 21, Arte Vol URVEY BULLETIN isp) ~ (4 © & n = -4 ~ e < Z n } Z = August, 1957 than those emerging later (2.65—2.85 mm. in total length). The oil droplet in the newly hatched fish was the same size (0.35 mm. in diameter) and color as it was in the newly fertilized egg. The greatest depth of the fry was 0.80 mm. across the yolk sac. It is interesting to note here that war- mouth eggs fertilized with sperm from a green sunfish showed no difference in rate of development from the rate described above. There was a high percentage of survival of both embryos and fry of the warmouth and green sunfish cross. Development and Growth of Lar- vae.—Specimens for a study of growth of larvae were collected from a nest in a lab- oratory aquarium. ‘The eggs were laid dur- ing the morning of June 24, 1947. Daily collections were made until the postlarvae left the nest. ‘Then the free-swimming lar- vae were transferred to an outdoor tank, where observation and sampling were con- tinued. The specimens, preserved in alco- hol, served as materials for the following descriptions of developmental stages. Ob- servations indicated that total length of a larva is a better indicator of the stage of its development than is actual age, which was known for each specimen. Measure- ments made with an ocular micrometer to the nearest 0.01 mm. were used in the de- scription of body form. In general, de- scriptions follow the procedure used by Fish (1932) ; terms for growth stages are those suggested by Hubbs (1943: 260). Prolarva, 3.4 mm., soon after hatching, fig. 144: Total length 3.4 mm.; length to anus 1.7 mm.; length of yolk sac 1.0 mm. Large oval yolk mass containing one oil droplet 0.3 mm. in diameter. Head de- flected sharply downward in front of yolk sac, making the midbrain the most forward part of the body and the forebrain lying directly beneath it. Head from front of forebrain to end of hindbrain 0.65 mm. Optic capsule faint, 0.23 mm. in diam- eter. Notochord straight. Myomeres in- complete anteriorly, numbering about 8 in front of anus and 17 behind anus. Embry- onic marginal fin fold complete except for faint break where intestine penetrates fin to outside. Fin extending forward on back to point 1.0 mm. from front of body. No visible ray development nor pigmentation. Prolarva, +.6 mm., 48 hours old, fig. 14B: Total length 4.6 mm.; length to Larimore: Lire History oF THE WaRMOUTH 47 vent 2.0 mm.; length of head 0.63 mm.; greatest depth of body in front of vent 0.70 mm.; greatest depth of body behind vent (excluding fin fold) 0.35 mm. Forebrain still somewhat deflected, with globular cerebellum extending high above anterior part of medulla. Eyes well pigmented. each 0.35 mm. in diameter; optic fissure still quite apparent. Mouth indistinct. Fin fold extending forward on back to point 1.2 mm. from front of body, entire except for break at anus. Very weak indications of fin rays below and above end of straight notochord, giving effect of diphycercal tail. Pectoral lobes present. Myomeres indis- tinct forward, about 10 to anus, 19 caudad from anus. Branchial elements forming. Postlarva, 5.3 mm., 4 days old, fig. 14C: Total length 5.3 mm.; length to anus 2.2 mm.; greatest depth of body anterior to anus 0.6 mm.; greatest depth of body posterior to anus 0.35 mm.; diameter of eye 0.41 mm.; length of head 0.90 mm. Cranial flexures almost straightened, but cerebellum high and bulblike. Optic cavity distinct. Fin fold beginning on back 1.5 mm. from front of body, becoming slightly narrow on caudal peduncle but wide again at tail. Faint indication of rays forming in areas of the anal and soft dorsal fins. Distinct fin rays on either side at end of the straight notochord. Kidney apparent through body wall. Pectoral fin lobes well developed but with no rays. Myomeres 10 anterior to anus, 19 posterior to anus. Branchial arches well formed and with de- veloping gills. Mouth gape extending obliquely forward from point below mid- dle of eye. Dark row of spots on either side of ventral fin fold; two large chro- matophores between bases of pectoral fins. Postlarva, 7.6 mm., fig. 14D: Total length 7.6 mm.; length to anus 3.4 mm.: length of head 1.5 mm.; diameter of eye 0.55 mm.; greatest depth of body anterior to anus 1.15 mm.; greatest depth of body posterior to anus 0.65 mm. Myomeres 11 before anus, 19 behind anus. Fin fold still complete except for break at anus; high at soft dorsal fin region, quite low above and below caudal peduncle. End of notochord bent upward at 40-degree angle, giving ap- pearance of heterocercal tail. Caudal fin rays well developed on lower side of noto- chord, with middle rays longest. Rays weak but distinct in unformed anal fin; 48 Ittrnois NaTturRAL History SurRvEY BULLETIN rays very weak in soft dorsal. Rays visible in pectoral fins. Mouth only moderately oblique. Pigmentation much more devel- oped. Row of spots along ventral fin fold spreading as stellate chromatophores over ventral surface of body. Series of dark dashes indicating lateral line. Heavy chro- matophore lying above anus. Some color apparent at base of caudal fin rays. Six stellate chromatophores between bases of pectoral fins and a row of five chromato- phores on each side across branchiostegals. Distinct, dark chromatophores scattered over top of head. Postlarva, 8.8 mm., fig. 14£: Total length 8.8 mm.; length to anus 3.9 mm.; length of head 2.0 mm.; length of snout 0.4 mm.; diameter of eye 0.75 mm.; depth of caudal peduncle 0.65 mm. Caudal pe- duncle long and narrow. Notochord with upturned end but tail appearing essentially homocercal. Fin fold present immediately anterior to anus. Anal and soft dorsal fins separate from caudal fin but each broad at base, due to some remaining parts of the embryonic marginal fin fold. Rays distinct in all fins present. Pelvic fins not devel- oped. Otic region large and clear. Anus protruding from ventral line of body. Lat- eral line chromatophores quite distinct. Ventral spots larger, with more chromato- phores scattered over head region. Postlarva, 12.0 mm., fig. 14F: Total length 12.0 mm.; length to anus 5.4 mm. ; length of head 2.8 mm.; diameter of eye 1.0 mm.; length of snout 0.7 mm.; great- est depth of body 2.45 mm.; length of cau- dal peduncle 2.4 mm.; depth of caudal peduncle 1.15 mm. Fin fold remaining only as short keel in front of anus. Pelvic fins present but weak and with indistinct rays. Spinous dorsal developed only as a row of short stubs. Distribution of pig- ment about the same as in 8.8 mm. stage, except spots appearing more distinct. More dark chromatophores around mouth; a ver- tical row present at base of caudal rays. Juvenile, 15.7 mm. (not photographed ). Body form essentially like that of adult fish. Total length 15.7 mm.; length to anus 7.0 mm.; length of head 4.35 mm.; diameter of eye 1.4 mm.; length of snout 0.85 mm.: greatest depth of body (at about anterior insertion of spinous dorsal) 3.7 mm.; length of caudal peduncle 2.9 mm., depth 1.5 mm. Anus protruding only Vol: 27; Art. I slightly from abdomen. No trace of em- bryonic marginal fin fold. Pelvic and spi- nous dorsal fins well formed. Pigmentation much heavier than in earlier stages. More color apparent over head and caudal pe- duncle. Belly rather free of pigment. Many large chromatophores scattered over back. Heavy row of spots forming circle behind eye and distributed over top of head. Chro- matophores noticeable on soft dorsal, anal, and caudal fins. Behavior of Larvae.—Activities of the warmouth larvae during their early life in the nest were limited to a few feeble movements. here was definite sequence, however, in the behavioral development of these small fish. The following description of behavior was based on laboratory ob- servations in aquariums with water of 24-25 degrees C. (75-77 degrees F.). Immediately upon hatching, the delicate prolarvae dropped down onto the sand and silt between coarse gravel particles of the nest. As the heavy yolk sac restricted movement, the prolarvae were difficult to see in the nest. When the prolarvae were between 36 and 48 hours old, fig. 14B, they began making feeble jumps an inch or so above the bottom of the nest. Most of these prolarvae were between gravel par- ticles in the nest, but a few could be seen resting on the flat surfaces of the largest particles. Although the yolk supply was about ex- hausted by the fourth day, the young fish still limited their movements to poorly di- rected jumps above the nest. They did not begin active swimming until the end of the fifth day, when they appeared as in fig. 14D. At this time, they swam about the nest in rather compact groups. Their movements were well controlled, and they showed remarkable ability to avoid a dip net. In the aquariums, these small fish had no food supply and starved in 10 or 11 days after hatching, but in outdoor tanks they began feeding at least by the seventh day after hatching. School formation among postlarval war- mouths in natural habitats was not so ob- vious as in postlarvae of certain other sunfishes, for the warmouths remained either among dense submerged vegetation or else in small pockets of open water closely surrounded by plants. The indi- vidual shown in fig. 14F was taken from a_ _— OO August, 1957 school near the nest in which it had hatched. The schools gradually dissolved as individuals began independent searches for food. No juvenile warmouths were observed in large groups. Factors Affecting Survival.—Rate of survival of warmouth eggs and young is influenced greatly by many physical and biological factors. Incubating eggs are readily affected by adverse weather condi- tions. Sudden drops in water tempera- tures promote the rapid growth of fungi infecting the eggs; often, entire nests of eggs are destroyed early in the spawning season as a result of low temperatures and fungi. For example, many warmouth nests in Venard Lake contained eggs during the last week in May, 1947, but, after several days of cold weather, the eggs in every nest observed were covered with fungi. Although heavy rains and high turbidity were not seen to affect nesting of adults or survival of fry, rapidly falling water levels might disturb nesting: In several Illinois lakes, minnows and sunfishes were observed destroying eggs and larvae in unprotected warmouth nests. In laboratory aquariums, warmouths were seen to rob poorly guarded nests; they charged in to snap up eggs or larvae. Postlarval and juvenile warmouths which have left the nest are eaten in great numbers by larger fish. Venard Lake sup- ported a heavy spawn of both largemouth bass and warmouths in the summer of 1947. On June 30 of that year, bass 1.75 inches long were voraciously feeding upon warmouths 0.75 inch long, which had been eating large numbers of postlarval warmouths. In the laboratory, a 0.75-inch warmouth ate 11 postlarvae (4 days old) in 5 minutes; another ate 12 in the same length of time. Survival of small warmouths is closely related to the density and composition of the fish population, the time of year, and the character of the habitat in which they are produced. Fry hatched late in the spawning season are in a population with a larger number of potential predators (fish only slightly larger than themselves) than are the fry produced earlier. How- ever, because the density of aquatic vegeta- tion increases during June and July, sur- vival in the late summer broods is fre- quently higher than in early broods. Larimore: Lire History oF THE WaARMOUTH 49 GROWTH Whether one is studying a single spe- cies of fish or the entire fish population of a body of water, it may become necessary to consider the growth of individuals in the one or more species involved. An analysis of growth is not always the objective of such a study, nor is determination of the morphological relationships which must be known before an analysis of growth can be made. The ultimate value of a growth study may come from its use in deter- mining the factors that govern or influence growth of fish under particular conditions. Relative Growth Various parts of a fish’s body grow at differential rather than uniform rates. The differential rates are not necessarily the same even for closely related species in the same habitat, nor for fish of the same spe- cies in different habitats. Consequently, when making a growth analysis of a se- lected species in a given habitat, one must determine several morphological relation- ships, namely, those of body growth to scale growth, body growth to growth of tail fin, and growth in length to growth in weight. Lewis & English (1949) and Hennemuth (1955) have plotted some of these relationships for two populations of Iowa warmouths, and Jenkins, Elkin, & Finnell (1955) for several populations of Oklahoma warmouths. Relation of Body Growth to Scale Growth.—A regression line to show the relationship between length of anterior radii of scales and length of body was con- structed from measurements of 1,068 war- mouths from Venard Lake and Park Pond, fig. 15. Data were obtained from collec- tions made approximately monthly begin- ning in June, 1948, and ending in Novem- ber, 1949. Regression lines constructed for warmouths from Venard Lake and for those from Park Pond proved to be so similar that data from the two lakes were combined. Key or representative scales were taken from the side of each of the fish near a point where the tip of the pectoral fin laid backward touched the third row of scales below the lateral line. Fish were sep- arated into total length classes at 0.5-inch 50 m N re) [e) oO oO oO (o) ow fo) 41 X ANTERIOR RADIUS OF SCALE IN INCHES rm iS ° re) ° lO 20 30 40 50 60 70 80 90 TOTAL LENGTH OF FISH IN INCHES Fig. 15.—Regression line expressing the re- lationship between total length of fish and radius of scale for 1,068 warmouths collected from Park Pond and Venard Lake, early June, 1948, through middle November, 1949. The dots show the anterior radius of scale X41 for fish of various total lengths (one-half-inch intervals). intervals, and the average of the total lengths for the fish in each of these classes was determined. Scales of these fish were placed in a scale-reading machine that magnified 41 times, and images of the an- terior radii of the scales were measured and averaged for the fish in each length class. Average total lengths of fish and corresponding average anterior radii of selected scales were used in developing I_ttinois NaturAL History SurRvEY BULLETIN Vol. 27, Art. 1 the regression line shown in fig. 15 and the following equation: L=0.5278+ 1.048 § where L=total length of fish in inches and S41 anterior radius of scale in inches Relation of Body Growth to Tail Growth.—Growth of the body of a fish in relation to growth of its tail, or caudal fin, may be ascertained by comparing the stand- ard length of the fish with its total length. As defined by Hubbs & Lagler (1947:13), total length includes the caudal fin, where- as standard length does not. The relationship between growth of body to growth of tail was calculated from measurements of 264 warmouths taken from Park Pond, summer, 1948, and No- vember, 1949, and Venard Lake, October, 1949. As the average body length of the warmouths increased, the average tail length became relatively less, table 17. In fish less than 4.0 inches total length, the average total length was 1.259 times the average standard length; in fish of 4.0 to 6.9 inches, the average total length was 1.240 times the average standard length; and, in fish longer than 6.9 inches, the average total length was 1.211 times the average standard length. Relation of Growth in Length to Growth in Weight.—The relationship between growth in length and growth in weight was calculated from data on 866 warmouths collected from Park Pond be- tween early June, 1948, and early No- vember, 1949. Size groups were estab- lished at 0.1-inch intervals. Average weights were determined for each group within the size range beginning with 3.3 and ending with 8.2 inches total length. The length-weight relationship for each of Table 17.—Factors derived from measurements of warmouths from Venard Lake, October, 1949, and Park Pond, summer, 1948, and November, 1949, for converting standard length (S.L.) to total length (T.L.), and the reverse, with the same and with different units of measurement. Tora. NuMBER LENGTH, OF IN Fi V40 5.1, oe us (Same Units) Under 4.0......... 130 0.795 AL OG ee eet te 93 0.806 OVveniG Oe oe 6 ten 41 0.826 Combined......... 264 0.809 ConvVeERSION Factors Sh tor. S.L. (Mm.) T.L. (Inches) (Sane Linits) to T.L. to S.L. (Inches) (Mm.) 1.259 0.0495 20.18 1.240 0.0488 20.48 1.211 0.0477 20.98 1.240 0.0487 20.52 August, 1957 the specimens (866) was expressed by the equation: log W= -4.49867+3.04902 log L where W+weight in grams and L=standard length in millime- ters Length-weight relationships were calcu- lated for the especially heavy and especially light warmouths in the Park Pond popula- tion. For warmouths heavier than aver- age, the equation was as follows: log W= -4.36191+3.01387 log L For those lighter than average, the equa- tion was as follows: log W= -4.35603+2.95352 log L From these equations, it may be seen that fish either heavier in relation to length, or lighter in relation to length, than the av- erage bore a systematic relationship of length to weight roughly paralleling that of the average. Such divergence from the average as was discernible was found par- ticularly among the fish of greater lengths and weights, fig. 16. Coefficient of Condition ‘The coefficient of condition (C), based on total length in inches and weight in pounds, was computed for the 866 Park Pond warmouths used in the analysis of length-weight relationships. Fish smaller than 3.3 inches total length were not con- sidered because individuals were weighed only to the nearest 0.01 pound, and greater weighing preciseness would have been nec- essary if smaller fish had been used; war- mouths of more than 8.2 inches total length were not used because few were available. Condition (C) increased progressively with increased size of fish. The average C (weighted to compensate for differences in numbers of individuals in groups) for each of several size groups, 3.34.2, f3-9-2, 5.3-6.2, 6.3-7.2, and 7.3-8.2 inches total length, was 72.6, 74.8, 78.6, 80.9, and 82.6, respectively. Warmouths within the size range 3.3—4.2 inches total length showed a wide seasonal variation in condition (C). This variation among small warmouths may have been caused by their dependence upon food items that fluc- tuated widely in abundance from month to month, such as cladocerans and certain in- sects and their larvae. Larger warmouths, Larimore: Lire History oF THE WARMOUTH 51 STANDARD LENGTH IN MILLIMETERS 50 100 150 200 0.80 350 — ALL FISH O70: ae! FISH HEAVIER THAN AVERAGE 300 —~- FISH LIGHTER 0.60 THAN AVERAGE 250 ” 2p) 2 0.50 a Z a 3 200. © z 0.40 = z = x F 150 ° ig 0.30 : = 100 0.20 : 0.10 i . 1.0 2.0 3.0 4.0 5.0 60 7.0 80 9.0 10.0 TOTAL LENGTH IN INCHES 0.00 Fig. 16.—Curves illustrating the relationship between length and weight of warmouths col- lected from Park Pond, early June, 1948, through middle November, 1949. feeding more upon crayfish and fish, varied less in body condition from one season to the next than did small warmouths. The condition (C) of warmouths for each of three size groups, 4.3—5.2, 5.3-6.2, 6.3—7.2 inches total length, was similar in seasonal fluctuations. A sudden, severe drop in condition occurred in September, 1948; a low level in condition lasted through October, and was followed by a rapid recovery by mid-November. Con- dition declined gradually during the winter and spring, but then began an increase that continued through May and June. Condi- tion remained relatively high and constant throughout the summer of 1949 and then declined during the fall months. Fig. 17 suggests that for the warmouths of Park Pond a definite cycle of condition associ- ated with seasons could not be established. Since food habits were studied for these warmouths collected from early October, 1948, to early November, 1949, it was pos- sible to associate the foods eaten with the seasonal variations in condition of the fish. The low level of condition in the winter (1948-49) was coincident with a compar- atively low consumption of crayfish, dip- aye Ittinois NaruraAL History SurveEY BULLETIN teran larvae, amphipods, and mayfly nymphs and with a comparatively high consumption of fish and dragonfly nymphs, fig. 6. During the spring of 1949, when @ @ @ rs @ °o 7.6 Z2 6.8 COEFFICIENT OF CONDITION 6.3'-7.2" the warmouths used in the present study are as follows: 1. There was a regular increase in the number of annuli accompanying an in- OCT NOV DEG JAN FEB MAR APR MAY JUN JUL AUG SEP OCT NOV 1948 1949 Fig. 17—Coefficient of condition of 392 warmouths of three size groups (6.3-7.2 inches, 5.3-6.2 inches, 4.3-5.2 inches) collected from Park Pond, early October, 1948, through early November, 1949. Warmouths collected and weighed in the summer of 1948 were so few in num- ber that data on them were not included in the graph. the warmouths were eating high percent- ages of crayfish (volume) and damselfly nymphs (frequency), the condition of these fish was steadily improving. The rela- tively good condition of warmouths during the summer of 1949 was associated with the extensive use of mayfly nymphs, cad- disfly larvae, and crayfish. There were no consistent differences in condition between male and female war- mouths in Park Pond. Scale Method of Calculating Growth The method of calculating warmouth growth from fish lengths and scale meas- urements is a composite of methods devel- oped by several authors but generally fol- lows the procedures suggested by Hile (1941). Validity of the Annulus as a Year- Mark.—Age and growth studies made from the scales of warmouths in Venard Lake and Park Pond indicate that the an- nulus is a reliable year-mark in this spe- cies. Hile (1941:201-4) outlined the most important features of a valid annu- lus. Four points used to test the validity of the scale method of age determination for crease in size of fish, and fish assigned to any single age group were within a cer- tain length range, table 18. 2. Lengths calculated from scale meas- urements agreed reasonably well with ac- tual lengths of fish of corresponding ages, tables 18 and 21. 3. Calculated lengths were similar for the same age groups of fish collected in different years and consistent for different age groups of fish collected in the same or different years. Because the calculated lengths were very similar for warmouths in the 1948 and 1949 Park Pond collec- tions, data for these two collections were Table 18.—Averages of total lengths of war- mouths of various ages collected from Park Pond, June, 1949. AVERAGE NuMBER Tora | RANGE oF Year or Lire| oF Fish | LenoTu, Tora. INCHES LENGTH wey 17 230 1.9-2.8 Bt. 35 3.53 2.8-4.6 Ar, 90 5.20 3.6-7.1 Soe 114 6.62 5.48.2 6x, 31 7.66 6.0-8.7 Vol. 27, Art.14 ee ee August, 1957 combined and are not shown separately ; however, consistency in calculated lengths of fish of the same and of different age groups is shown in tables 21 and 26. 4. There was similarity among war- mouths of different year classes with re- spect to growth rates in certain calendar years, tables 23 and 24. Characteristics of the Annulus.— The true annulus on the warmouth scale appears as a result of resumption of growth of body and scales after the cessa- cae ND ae. ey) AN Ni We sy, Larimore: Lire History oF THE WARMOUTH 53 tion of growth during winter months. True annuli or year-marks usually show several rather definite characteristics, fig. 18. Across the anterior field of the scale the annulus appears as a break in the arrange- ment of circuli; it is bordered on the in- side by closely spaced, incomplete circuli and on the outside by complete, widely spaced circuli. The radii in the anterior field are slightly distorted in the region of the annulus. On the lateral fields of the scale, the annulus and newly formed circuli Fig. 18—Warmouth scale: 4, wide spacing of circuli especially evident following resump- tion of growth in spring; B, first annulus; C, second annulus; D, crowding of circuli during period of slow growth resulting from habitat disturbance; £, new circuli cutting across ends of circuli laid down in previous season. 54 “cut over’ the circuli laid down near the end of the previous season. The annulus extends only part way across the posterior field of the scale. Slight differences in spacing of circuli and in the lengths of ctenii (small surface spines on scale) may aid in recognizing the location of the year- mark in the posterior field. The first annulus formed on the war- mouth scale does not show as much “‘cut- ting over” in the lateral fields as do later annuli, nor are the differences in spacing of circuli so apparent in the first as in later annuli. The differences which may exist in length and distribution of ctenii are most useful in recognizing the first an- nulus. Annuli formed later are generally more difficult to recognize with certainty, mainly because they are closer together than those earlier marks laid down when the fish was increasing rapidly in length. Time of Annulus Completion.— In 1949, the time of annulus completion in warmouths at Park Pond was deter- mined from 129 specimens collected be- tween April 7 and May 20. Sixty-eight per cent of the warmouths collected May 13 and 14 had laid down the year’s annuli on their scales, so that the average time of annulus completion appeared to be about the first week of May, table 19, at which time the water temperature 1 foot below the surface of the water was about 70 de- grees F., fig. 9. Small fish usually lay down the year-mark earlier in the spring than do the larger ones, because the former begin to grow at an earlier date. Fifteen per cent of 39 fish collected from Park Pond on April 7 and 9 showed new an- nuli on their scales; all but one of these fish were less than 4 inches total length. As annulus formation is associated with the resumption of growth of the fish in spring, the annuli on the scales of fish may not be completed at the same time each year, and the time may vary from one pop- ulation to another. Warmouths in Venard Lake showed a period of annulus forma- tion in 1949 that differed from the pe- riod shown by the warmouths in Park Pond. In the fish collected from Park Pond, some year-marks appeared before April 7, but only 68 per cent of the fish in the May 13-14 collections had completed annulus formation; the period in which annuli were being completed covered more Ittinors NatrurAL History SurvEY BULLETIN Vol. 27, Art. 1 than 6 weeks. In Venard Lake, on the other hand, none of the specimens col- lected on April 5 had formed an annulus; in the collection of May 12, about 5 weeks later, 30 of 31 fish (nearly 97 per cent) had completed annulus formation. Ecological conditions in Venard Lake, where warmouths were confined to a small area having only minor fluctuations in Table 19.—Percentages of warmouths with and without new annuli, Park Pond collec- tions, 1949. a ee ee PER- PeEr- DaTE NuMBER | cENTAGE BA eee OF OF LACKING , CoLLEcTION FisH heer bait: ANNULI April7-9....| 39 85 15 May 13-14...| 38 32 68 Mayr 16.56. 40 20 80 May 20..... if) 8 92 depth, probably were more nearly uniform than in Park Pond, where warmouths were found in shallow sloughs, deep chan- nels, and open waters. It seems reasonable to believe that a population inhabiting a pond with a wide variety of physical con- ditions might show annulus formation over a longer period than a population exposed to more nearly uniform physical conditions. Furthermore, in Park Pond, fish of many other species were competing with war- mouths for the natural foods available in early spring. ; False Annuli.—Some scales of war- mouths show false annuli, or marks which — are not true year-marks but merely indica- tions of physiological disturbances during growing seasons. False marks were found on the scales of many fish from Park Pond. — Most of them could be recognized with confidence. They did not appear uniformly throughout a population or regularly at definite times of year. False marks were formed on the scales of a large part of the warmouth population of Venard Lake during August of 1948. These marks could be distinguished, par- ticularly in the 1947 year class, on the scales of fish collected in succeeding years. Since monthly collections allowed the false annuli to be originally dated and to be | recognized by their location in relation to | August, 1957 true annuli on the scales in later collec- tions, these marks gave little trouble in age determinations. The formation of the marks coincided with a 4-week period of shoreline dredging with a dragline. Such a severe disturbance of the habitat must have reduced the food supply or its avail- ability and caused a temporary stoppage of growth that produced the false marks. Growth in Park Pond Park Pond, an 18-acre lake in a flooded stripmine area, in 1948 and 1949 sup- ported an old (60 years at least), rather large fish population of about 36 species native to the region. Most of these spe- cies had been introduced into the lake from the Salt Fork in times of flood, page 4. Collection and Preparation of Ma- terials.—In the period beginning June 7, 1948, and ending November 12, 1949, 1,420 warmouths were collected from Park Pond. Hoop nets, fig. 19, were used in collecting 367 warmouths; of these fish, 298 were collected between early June and mid-September, 1948, and 69 between LarimoreE: Lire History oF THE WARMOUTH 55 June 27 and July 5, 1949. An electric shocker rigged for operation from a row- boat (Larimore, Durham, & Bennett 1950) was used to collect specimens for growth analyses and food studies. A total of 788 fish were taken by this method in collections made at monthly intervals from early October, 1948, to early November, 1949, except that no collections were made in February and October, 1949. Even though Park Pond supported the largest naturally established warmouth population that had then been examined in Illinois, warmouths were never taken there in great numbers; a good day’s take might consist of 2 dozen warmouths from the usual set of six hoop nets or 50 warmouths from the operation of the electric shocker. Large specimens predominated in the hoop net catches; fish of all sizes were present in collections made by shocking. On August 22, 1949, rotenone was applied to a shal- low, isolated, 0.47-acre slough in Park Pond, and a census was made of the fish population. Scales for growth studies were taken from 265 of the 504 war- mouths collected from this area. Fig. 19.—Collecting fish with a hoop net in Park Pond. 56 Ages were determined for 1,328 of the 1,420 warmouths collected (265 from the shallow, isolated slough and 1,063 from other parts of Park Pond). Scales from 84 fish were regenerated and unreadable; scales of 8 other specimens were so difficult to read that ages could not be determined with certainty. Fish from the slough that was treated with rotenone were considered separately because they showed growth rates significantly different from those. taken in the other collections. Impressions of the warmouth scales were made on cellu- lose acetate slides, and the images of these impressions were projected for study at a magnification of 41 diameters. Measure- ments along the median, anterior radius of a magnified scale image were marked on a manila paper strip, and the strip was used for calculating past growth on a nomograph, as described by Carlander & Smith (1944). Calculated lengths, based on a straight-line relation between scale length and body length, were corrected for an intercept of 0.53 inch in body length (fig. 15 and equation on page 50). The following sections, “Growth Dif- ferences Between Sexes,’ “History of Successive Year Classes,” ‘‘Fluctuations in Annual Growth,” and ‘Seasonal Growth,” refer to Park Pond warmouths other than those from the slough. Growth Differences Between Sexes.—Sex was determined by dissection or by visible discharge of sex products for I_ttino1is NATURAL History SuRVEY BULLETIN 600 specimens in year classes 1944 through Vol. 27, Art. 1 1948. Calculated lengths of males and fe- — males of each of the year classes were aver- aged and compared, table 20. Fish in both the 1943 and 1949 year classes were rep- resented by so few specimens for which sex was determined that they were omit- ted from the calculations. Very consistent, although rather small, differences existed between the growth rates of males and females. larger than females at the end of each year of life in the five year classes considered. The greatest differences occurred in the 1944 year class, but the small number of specimens (only seven females) made this growth comparison less reliable than that for other year classes. The next oldest brood, the 1945 year class, was represented Se Males were — ee a by 187 specimens. Males in this group av- — eraged only a little longer than females. — Schoffman (1940:32) observed that the ¥ lengths and weights of male and female — warmouths of the same ages in Reelfoot | Lake, Tennessee, were either the same or_ only slightly different. Since the actual differences in lengths — of male and female warmouths were rather small in those year classes represented by substantial numbers of specimens, data for — the two sexes were not separated in the growth analyses discussed in the following paragraphs. History of Successive Year Classes. — —All the specimens were assigned to year Table 20.—Average calculated total lengths in inches for male and female warmouths, ~ representing five year classes, collected from Park Pond, October, 1948, through November, 1949. — AVERAGE CALCULATED Tota, LENGTH IN INCHES AT END OF InpIcATED YEAR OF LIFE Ciae NuMBER Crags SEx OF ; FisH 1 1944..... Male 15 1.64 Female 7 1.46 1945. Male 102 1/3 Female 85 1.62 1946.. Male 84 1.56 Female 85 1.56 1947.. Male 79 1.58 Female 7A 1.48 1948. Male 33 1.62 Female 39 1.61 2 3 4 5 3.31 3.39 6.68 oe SxOl 4.72 Soo 6.35 3.49 4.89 5.88 3.34 4.68 5.85 2.85 4.21 2.81 4.11 2.99 2.61 August, 1957 LarimoreE: Lire History oF THE WARMOUTH at Table 21.—Average calculated total lengths in inches for 1,063 warmouths, representing nine year classes, collected from Park Pond, June, 1948, through November, 1949. AVERAGE CALCULATED Total LENGTH IN INCHES aT END oF INDICATED YEAR OF Lire* NuMBER YeArR Crass OF FisH 1 2 3 RO40 4.5. 62. 1 1.61 3.08 4.20 24S 6 1.58 2.86 4.39 7 ae 10 1.47 2.89 4.54 MA Sia sls 46 1.59 Bo DS 5.28 HOAA ee. 12D 1.62 STi Sets: “Ci aa 362 75 3.80 4.86 META GA fathom ocr 239 1.59 2.90 4.26 BA ot 187 £55 2285 EES Se ee 90 1.63 Weighted MBPT Ces ree Js 2. | L.0F 3.38 4.91 4 5 OH4e 7 8 5.807 | 6.33921? 6938) 7.94. |, S161 Coca ee ae Ne a ae en 508. 7.57 pn 8 Oe | 8.44 7.00 | 7.69 | 8.76 6.75 | 7.10 5.99 6.40 | 7.44 | 8.02 | 8.47 | 8.56 *Average for last year in each year class based on fish in which annulus for current year was present. classes on the basis of number of true an- nuli on their scales. The length of each fish at the end of each year of life was cal- culated from its scale measurements. The calculated lengths for each year of life were then averaged for fish of each year class. In the length calculations for 1948 growth of fish collected in 1949, only those fish taken after annulus formation in May could be used. The calculated lengths for 1,063 warmouths, table 21, suggested the following conclusions: 1. Average calculated lengths for fish of the 1943, 1944, and 1945 year classes were greater in most years of life than the weighted averages for the fish of all year classes (averages were weighted to com- pensate for differences in numbers of fish in the various groups) ; fish of both the 1944 and 1945 year classes showed less than the average length for the last complete grow- ing season (1948) prior to capture. 2. Average calculated lengths for fish of the 1946 and 1947 year classes were less in most years of life than the weighted ay- erages for the fish of all year classes. 3. Average calculated lengths exhib- ited no large growth rate differences for the same years of life among warmouths caught at different ages—no phenomenon of apparent change in growth rates as de- scribed by Lee (1912:9). (However. Table 22.—Average calculated total lengths in inches for each year of life of 1,063 war- mouths collected from Park Pond, June, 1948—November, 1949, with equivalent standard lengths in millimeters and weights in pounds and grams. Calculated annual increments in lengths and weights are based on these averages. ANNUAL | CALCULATED Cc ANNUAL Tora. STANDARD - | Increment | ~AUCULATED : WEIGHT, WEIGHT INCREMENT Year or Lire LENGTH LENGTH, x 2 or ToraL = > : Pounpbs Grams = or WEIGHT INCHES INCHES LeNcTH, Pacis” INCHES es BES 1.64 33 0.004 1.8 1.64 0.004 Z... 3.38 68 0.026 11.8 1.74 0.022 Bi... 4.91 101 0.088 39-9 B53 0.062 aa... 6.40 131 0.200 90.7 1.49 0.112 ee. 7.44 153 0.337 152.9 1.04 0.137 6... 8.02 168 0.432 196.0 0.58 0.095 i. 8.47 178 0.510 231.3 0.45 | 0.078 By. 8.56 180 C2521 239.0 0.09 | 0.017 WEIGHT INCREMENT IN POUNDS 58 Ittrnois NaTturAL History SurvEY BULLETIN Vol. 27, Art. 1 10.0 20 0.15 0.60 o Fs} es 215 w” n” ¢ S = z 60 LENGTH 0.408 E 0.10 z — Sie WEIGHT / Ge Ey = / & 40 WEIGHT = 3 } za o = WwW wy ae LENGTH 0.05 - YU. 20 2 = 00 | Ee Name bei > ag Gia = AGE IN YEARS Fig. 20.—Averages of calculated total lengths and calculated weights at end of each year of life for 1,063 warmouths of various ages from Park Pond, early June, 1948, through middle November, 1949. Lee’s phenomenon was evident in Venard Lake warmouths, figs. 23 and 24.) Annual length increments based on cal- culated lengths were determined for each year of life of the 1,063 warmouths, table 22. These length increments were greatest for the second year of life and decreased thereafter; they declined rapidly after the fourth year and were very slight in the eighth year of life. The pattern of weight increase was dif- ferent from that of length increase. Aver- age calculated weights in pounds, corre- sponding to average calculated lengths in inches (length-weight prediction equation, page 51), furnish evidence that in the war- mouths studied the rate of weight in- crease was slow during the first 2 years, | 2 3. 4 5 56ers YEAR OF LIFE Fig. 21.—Averages of annual increments of calculated total lengths and calculated weights in each year of life for 1,063 warmouths from Park Pond, early June, 1948, through middle ~ November, 1949. reached a peak the fifth year, and declined rapidly in the following years, table 22. Fig. 20 shows the average lengths and weights; fig. 21 shows the increments of — length and weight for each year of life. Fluctuations in Annual Growth.— There were calendar years of good and of — poor growth for all year classes of war- mouths at Park Pond. These years of good and of poor growth were evident even though warmouths in certain year classes were of consistently larger or smaller sizes — than the average for all warmouths. Using the average annual length incre- — ment for all warmouths in each year of © life as a base, tables 21 and 22, one can cal- — culate the percentage of the expected in- — crement attained by each year class for Table 23—Average percentage of expected annual length increment attained in each year of life in eight separate year classes of 1,062 warmouths collected from Park Pond, June, 1948—-November, 1949. NuMBER YEAR CLass OF Fis 1 2 BOA Tee ey. 6 96 74 GY 9 Gea en 10 OO n2e| 82 194s ee ti So 46 o7 mI 95 1 hey: © eae ae 122 99 124 | Pe a) ee Saas LOJE Me AS IGAGICES ot =| 239 | 97 75 jf 9 sae aa 187 ote | 75 Oy te ee ae 90 | 99 | AVERAGE PERCENTAGE OF ExpecreD ANNUAL LENGTH INCREMENT ATTAINED IN INDICATED YEAR OF LIFE 3 4 5 6 ¥ 100 91 110 176 149 108 97 134 116 133 115 66 128 68 34 69 76 88 | j j } : : : August, 1957 each year of life and for each calendar year, table 23. Percentages of expected growth during selected calendar years may be read from table 23 in diagonal rows from lower left to upper right. The percentages of ex- pected growth in each calendar year, when averaged, show clearly the fluctuations in annual growth, table 24. Actual length increments exceeded the expected increments in only 1945 and 1946, table 24. Poor growth in 1942 and 1943 may have been due to heavy floods, which caused the water to remain muddy for 6 or 7 weeks during the early summer of each of these years. The exceptionally good growth of war- mouths during 1945 and 1946 may have re- sulted from an artificial thinning of the fish population. On June 26, 1945, May 15, 1946, and July 29, 1946, Dr. George W. Bennett and other members of the I]li- nois Natural History Survey staff sprayed most of the shallow waters of Park Pond with rotenone to reduce the numbers of small fish in the population. Although no estimate could be made of the percentage of the total fish population killed by these par- tial poisoning operations, the great num- ber of small fish destroyed may well have allowed a substantial increase in growth rates of the surviving fish. Seasonal Growth.—Growth patterns of the 1946, 1947, and 1948 year classes of warmouths in Park Pond during the summer of 1949 are shown in fig. 22. The length increment for each fish was calcu- lated from scales. The growth increment on each scale used was measured on the Table 24.—Average percentages of expected annual length increment attained in each cal- endar year by warmouths collected from Park Pond, June, 1948—November, 1949; year classes combined. AVERAGE PERCENTAGE OF Be cons - Numser |ExpecreD ANNUAL LENGTH wee Vea OF INCREMENT ATTAINED Fisu In Eacu YEAR OF LIFE nO41..... 6 96 1942... 16 82 n943).... 62 93 1944. 194 98 1945.. 546 114 1946. 785 128 1947... 972 91 1948... 526 74 Larimore: Lire History oF THE WARMOUTH 59 1948 YEAR CLASS 1.0 1947 YEAR CLASS 1946 YEAR CLASS INCREASE IN LENGTH FOR 1949 SEASON (INCHES) (e) no MAY JUN JUL AUG SEP OCT NOV Fig. 22.—Averages of length increases of warmouths of the 1946, 1947, and 1948 year classes in Park Pond during the 1949 growing season. The growth increment for each war- mouth was calculated from scale growth out- side of the last annulus. median anterior radius from the outermost annulus to the margin of the scale. Aver- age monthly length increments were calcu- lated from scale collections made each month except October in a period that be- gan in May and extended into November. When more than one collection was made in a single month, the collections were combined and an average date was used. In this particular analysis, year classes other than those of 1946-1948 could not be used because they were not represented by sufficient numbers of warmouths to give validity to the calculations. Growth was rapid for the three year classes in May and June, and this good growth continued through July for the 1948 year class, fig. 22. Growth rates de- creased in July for the 1946 and 1947 year classes and improved considerably in August. Little or no growth was evident in the three year classes after August. Cer- tain general differences were discernible between the fish of these year classes. The oldest fish (1946 year class) showed a mid- summer slump in growth and had com- pleted their seasonal growth by September, whereas the youngest fish (1948 year class) 60 grew rapidly through July and showed some growth in each of the months through October. The growth pattern for the 1947 year class was intermediate between the patterns for the 1946 and 1948 year classes. Seasonal growth rates of three year classes of warmouths in Venard Lake are shown in figs. 23 and 24. Measurements of warmouths from Park Pond, fig. 22, from Venard Lake, figs. 23 Ittinois NATuRAL History SuRVEY BULLETIN Vol. 27, Art. 1 long. Most of these warmouths were less than 3.5 inches in length. Age determinations for 265 of the 504 warmouths revealed a growth rate consid- erably less than was found in other areas of Park Pond, table 25. Of the 265 speci- mens aged, very good growth was found in 23 large fish belonging to the 1944 and 1945 year classes. These fish did not seem to be representative of the population of Table 25.—Average of calculated lengths of 265 warmouths from which scale samples were taken, after being collected from Park Pond Slough, shown with similar calculated lengths of warmouths from other parts of Park Pond. e Ca.cuLatep Tora LenctH at Enp or AVERAGE YEAR NuMBER INDICATED YEAR OF LIFE Tora. Group oF FiIsH Ces OF LENGTH FisH AT 2 3 = 5 CapTURE Fast-growing warmouths from 1944 2 1.74 4.07 5.38 6.65 Ta TESS slough 1945 21 1.91 3.83 5.14 5.87 6.15 Slow-growing 1945 10 1.56 2.90 4.00 4.86 5,27 warmouths from 1946 74 1.54 2.85 3.97 4.59 slough 1947 93 1.46 2.54 3.34 1948 52 1.48 2.50 1949 13 1.65 Slow-growing warmouths from 242 1.50 2.64 3.64 4.62 slough, average Warmouths from Combined other Park Pond year areas, average classes 1,063 1.64 3.38 4.91 6.40 and 24, and from certain Oklahoma wa- ters (Jenkins, Elkin, & Finnell 1955 :42) indicated an apparent decrease in the aver- age lengths of the fish of some age groups in July or August. This apparent decrease may have been due to changes in habits or distribution of the warmouths from the early part to the middle part of the sum- mer, changes which might have affected the efficiency or selectivity of the collecting method, with a result that a proportionally smaller number of large members in each age group was taken. Growth in Localized Population. —In the isolated, 0.47-acre Park Pond slough to which rotenone was applied in 1949, warmouths comprised 10.4 per cent of the weight of the fish population. Al- though this weight represented 504 indi- viduals, only 18 were more than 6 inches the slough. Their history of rapid growth suggested they had only recently moved into this area. ee eee eee All of the smaller specimens in this — slough showed consistently poorer growth than warmouths from other areas of Park Pond. A study of the fish population of the slough indicated that (1) isolated pop- — ulations of warmouths existed within the total warmouth population of Park Pond; (2) individuals of these isolated popula- tions, most of them in dense weed beds, © grew slowly; and (3) individuals of these populations appeared to remain in the same — locations throughout their life spans. Compensatory Growth.—Three hun- — dred thirteen warmouths from Park Pond ~ were separated into three size groups based — on calculated lengths of fish at the end of | the first year of life, table 26. The average August, 1957 length increment for each year of life was then calculated for each size group as a means of determining the growth rate— whether fast, intermediate, or slow. Of the 313 warmouths considered, 94 had been collected with hoop nets during the summer of 1948; these 94 were fish of the 1944 year class and were faster-grow- ing individuals than the specimens (219) that had been taken from the slough. War- mouths taken from the slough had been collected after being poisoned with rote- none; they belonged to the 1946, 1947, and 1948 year classes, table 26. For the fish taken in hoop nets, the difference in average calculated lengths be- tween the largest and smallest size groups was 0).55 inch for the first year of life, 0.74 inch for the second, 0.55 inch for the third, and 0.42 inch for the fourth. The decline in differences between these two size groups in the third and fourth years of life may indicate compensatory growth among LarimorE: Lire History oF THE WARMOUTH 61 individuals of the smallest group in these years. However, the compensatory growth that occurred was slight and it did not overcome the length advantage held by the fish that grew most rapidly during the first year of life. In the slow-growing population from the slough, the maximum differences in length between the two extreme size groups of the various year classes declined little or not at all after the second year. In the 1946 year class, after an increase in length difference at the end of the second year, the differences were about the same at the end of the third and fourth growing seasons, table 26. A study of compensatory growth in these four year classes of warmouths from Park Pond suggested the following con- clusions: 1. Warmouths that were largest at the end of the first year of life increased this length advantage in the second year of life. Table 26—Compensatory growth, in inches, in four year classes of warmouths collected from Park Pond. Fish in the 1944 year class were collected in hoop nets from several parts of Park Pond in the summer of 1948; those in 1946-1948 year classes were taken from a slough to which poison was applied on August 22, 1949. CALCULATED AVERAGE | CALCULATED AVERAGE Year Chass Group or Fisu, Basep Tora LenctuH at Enp | Lencru INCREMENT IN hp PiAce | o™ CarcutateD Toran | NumBer | or Inpicatep YEAR OF | INDICATED YEAR OF s LencTH IN INCHES AT OF Lire pices ae Enp or First YEAR OF Fisu Lire 1 2) 3 4 1 2 3 4 Below 1.45 wp MSS SeIouOMOS lon OMLese 22 Oei rel sm ten ae 1944 1.45-1.70 42 1.58 13.80) 15.74 16.76 1.58 2.22 |1.94 9/1 02 (Entire pond) {Over 1.70 30 1.88 |4.27 |6.23 |7.12 |1.88 |2.39 |1.96 |0.89 Maximum difference OPS 7429 OM SIS ia OAD Ie te toe |e Dee | eee 1946 Below 1.3 13 LeQONDE 49) Br Ol 4255120) MDOT OM) OnG4 (Slough) 1.3-1.6 33 143) 12263 18.74) |42354|0 43a 20) 11) On6l Over 1.6 28 1.84 |3.28 |4.41 |5.047]1.84 |1.44 11.13 |0.63* Maximum difference 0.64 |0.79 10.80 |0.79 Below 1.3 19 22 224 1S) Ae PU SPN OPES KO) Stoel en a! 1947 1.3-1.6 55 NA ee 2A | Seiie Stal OG a ORs Orne (Slough) Over 1.6 19 Lee SOS |Sia7i9e a lliestekle WV BOD TKO). HAS. ye 2 Maximum difference 0.59 |0.79 10.68 Below 1.3 14 1.24 |2.24* 1.24 |1.00* . 1948 1.3-1.6 24 1.41 |2.42* 1.41 1.01* (Slough) Over 1.6 14 1.82 |2.89*}. 182 Ore Maximum difference 0.58 |0.65 *Empirical length representing growth to August 22, 1949. 62 Intinors NATURAL History SuRVEY BULLETIN 2. Warmouths that were smallest at the end of the first year of life showed no com- pensatory growth in the second year but showed a slight compensatory growth in the third year. 3. Although warmouths that grew fast the first year of life underwent a decline in annual length increment after the sec- ond growing season, they retained their length advantage over warmouths that grew slowly the first year. 4. Warmouths that grew slowly the first year of life showed more compensa- tory growth in later years if they were members of fast-growing populations than if they were members of slow-growing populations. These conclusions are in fair agreement with those from similar studies done on several other sunfishes. Hubbs & Coop- er (1935:678) found no compensatory growth during the second year of life in the longear sunfish, pumpkinseed, or blue- gill, or in bluegill pumpkinseed hybrids. Their data did not include growth rates beyond the second year. For the rock bass, Hile (1941:332) stated: “First-year ad- vantage in size may be retained over | or 2 additional years, but more probably it will be increased in the second and/or third year of life. Compensatory growth occurs in the later years.” Sizes and Longevity.—A 9.6-inch male was the largest warmouth collected from Park Pond. This fish weighed 1.0 pound and was 6 years of age. The ma- jority of the large fish were males. Al- though the males grew slightly faster than the females, table 20, it did not necessarily follow that the males reached greater max- imum sizes than did the females. The oc- currence of more large males than large females in the collections may have indi- cated only that the former were more read- ily taken than were the latter—a logical hypothesis in view of the differences in be- havior during the nesting season. ‘The sed- entary nest-guarding habits of the males would have made them very vulnerable to collection by shocking. Schoffman (1940:36) mentioned spawn- ing habits to explain the greater percentage of females than males in the groups of large warmouths he collected from Reel- foot Lake, Tennessee. As his collections were taken with traps operated during the Vol. 27, Art. 1] breeding season, nest-guarding males were not caught so readily as females. The larg- est warmouth handled by Schoffman (1940:34) was a 9.29-inch female. Growth in Venard Lake In 1948 and 1949, warmouths in Ven- ard Lake, an artificial lake of 3.2 acres, were associated with only one other species, — the largemouth bass. Both species had — been introduced in April, 1947, page 5. | The 1,102 Venard Lake fish used in this study were from collections made with an electric shocker each month (ex- cept January and February) in a period — beginning September, 1948, and ending October, 1949. Methods used for scale preparation and age determination were — similar to those described for the collec- tions from Park Pond. Since Venard was a recently stocked — lake, it contained only a small number of ~ year classes of warmouths: 1947, 1948, — and 1949. A comparison of growth rates — was made between warmouths of the first, — fast-growing year class (1947) and those — of the two following year classes (1948 and 1949). The following points seem ap- — parent, figs. 23 and 24: 1. Both actual and calculated lengths of warmouths of the first year class to be spawned in the lake (1947) averaged more at the end of the first year and of each suc- ceeding year of life than did those of later — year classes. 2. The actual length range for mem- bers of the first year class was greater than that for members of each succeeding year — class. 3. The average calculated lengths of warmouths of 1947 and 1948 year classes collected in successive months of 1949 showed a decline. 4, The average annual growth of war- mouths in Venard Lake was very similar to that of warmouths in their first 3 years of life in Park Pond, table 27, in spite of large ecological differences in the two habi- tats. Growth in Other Water Areas The rate of growth of warmouths may be influenced by various environmental fac- tors or combinations of them. This fact is August, 1957 illustrated by the differences observed in the growth rates of warmouths taken from 12 Illinois water areas, table 27. _ The most rapid growth recorded in I[1hi- ‘“nois warmouths was in Enright Pond in ~McLean County in which some members of the first brood produced in the lake at- tained 6 inches in total length during their first 13 months. Thinning the total fish LarIMoRE: Lire History oF THE WARMOUTH 63 population by intensive angling resulted in an increase in the growth rate of war- mouths in Onized Lake, a 2-acre body of water in central Illinois (Bennett 1945: 396-7). Exceptionally rapid growth of war- mouths usually accompanies the expansion of fish populations in new reservoirs. Dur- ing the first 6 years after impoundment of 7.0 ] RANGE OF ACTUAL LENGTHS — AVERAGE OF ACTUAL LENGTHS 6.0 5.0 op) LJ a@ O Z 4.0 TOTAL LENGTH, er) .e) 2.0 _ AVERAGE OF CGALCULATED LENGTHS AT FIRST ANNULUS AVERAGE OF GALCULATED LENGTHS AT SECOND ANNULUS SEP OCT NOV DEC JAN FEB MAR APR MAY JUN JUL AUG SEP OCT 1948 1949 Fig. 23.—Averages of actual total lengths and averages of calculated total lengths at time of formation of first annulus and at time of formation of second annulus for warmouths of the 1947 year class taken in 12 collections from Venard Lake, late September, 1948, through middle October, 1949; also range of actual total lengths in each collection. 64 Ittinors NATURAL History SuRVEY BULLETIN 5.0 Vol..27, ATi RANGE OF ACTUAL LENGTHS AVERAGE OF CALCULATED LENGTHS AT FIRST ANNULUS a oO INCHES TOTAL LENGTH, —— AVERAGE OF ACTUAL LENGTHS 1948 YEAR CLASS 1949 YEAR CLASS SEP OCT NOV DEC JAN FEB MAR APR MAY JUN JUL AUG SEP OCT — 1948 1949 Fig. 24.—Averages of actual total lengths and averages of calculated total lengths at time of formation of first annulus for warmouths of the 1948 year class taken in 10 collections from Venard Lake, early October, 1948, through middle October, 1949; averages of actual total lengths of warmouths of the 1949 year class taken in 4 collections, late June through late October, 1949; also range of actual total lengths in each collection. Lake Glendale, an 82-acre lake in Pope County, Illinois, warmouths showed a growth rate that was exceptionally fast for the species (Dr. Donald F. Hansen of the Illinois Natural History Survey, unpub- lished studies of Lake Glendale). Another example of improved growth rate in a new impoundment is given by Hall & Jenkins (1953:34) ; they found that, in Tenkiller Reservoir in Oklahoma, the growth rate of warmouths was rapid during the first year of impoundment. Jenkins (1953:79) found that in Grand Lake, Oklahoma, the growth rate of warmouths gradually de- clined during the years of impoundment. Data from several studies of warmouth growth in other states are summarized by Carlander (1950:191-2; 1953:370-1). An inspection of these data and those given in table 27 reveals a wide range of differ- ences in warmouth growth rates. PARASITISM No attempt will be made here to survey all published records concerning parasites of the warmouth. Reference should be be made, however, to several important studies involving autopsies of compara- tively large numbers of warmouths. Holl (1932:99-100) examined 90 warmouths from North Carolina and discovered an in- August, 1957 teresting seasonal fluctuation in relative numbers of parasites and in percentages of fish infested. In a study of centrarchids from southern Florida, Bangham (1939: 265) examined 143 warmouths and found all of them infested with parasites of one Larimore: Lire History oF THE WARMOUTH 65 the genus Physa, any one of several spe- cies of fish, and the great blue heron, drdes herodias L. As little age immunity has been demonstrated in intermediate hosts of most flukes, the numbers of metacer- cariae of this strigeid probably continue Table 27.—Growth rates of warmouths in 13 water areas in Illinois. : CatcuLaTeD Toray Lencru ar END oF YEAR NuMBER InpicATED YEAR OF LIFE Water AREA County OF OF Co.ttection| FisH 1 2 3 + 5 6 a Park Pond.........|Vermilion 1948-49 1,063). (0256. | 324: 4.9 [6.4 AA BLO 825 Park Pond Slough. .|Vermilion 1949 242 Wash | PP sion TZ8.6 Venard Lake......./McLean 1948-49 334) 127), 322 46 Woized Lake*...... Madison 1941 101 1.4 | 4.0 | 6.1 Lake Glendale... .. .|Pope 1945-46 10S, QFE 4 GG. 2 Mississippi Rivery.. . 1944 260 LS A408 es eral Lake Chautauqua...|Macon 1947 SOim ANE 22/5 Ps 5) eS SeGns 40-and-8 Lake......|Henry 1954 D2. Ne deed. all eed Nae Ge Ould. 0 Staunton Lake..... Macoupin 1953 Eafe esha ihe M A5RG at Si Mount Clare Lake. . |Macoupin 1953 Ge | LSE a AR Gwe 5he/ McKenzie Lake..... Montgomery | 1952 12. LB Dae) Sree eA ES a Ome) 4: Weldon Springs...../De Witt 1952 yee ON Nie or |. Sp Fairmount Quarries. |Vermilion 1953 NO TE Se Oo) 4h SE *From Bennect 1945 :397. 7From Upper Mississippi River Conservation Committee or more species. The fish populations from which these specimens were taken con- tained relatively high concentrations of warmouths. Venard (1941:15) found that of 45 warmouths examined from Reelfoot Lake, Tennessee, all were para- sitized. Bangham & Venard (1942:33) listed 22 species of parasites from 58 speci- mens examined from Reelfoot Lake; all of the specimens were infested with para- sites. A comprehensive investigation of war- mouth parasites was not made in this study. The following brief discussions are of the general relationships between the hosts and four common parasites of war- mouths from Venard Lake and Park Pond.* The strigeid fluke, Posthodiplostomum minimum (MacCallum), was the most abundant parasite of the warmouths in Park Pond. Its hosts include a snail of *Dr. L. J. Thomas, University of Illinois, checked the identification of the cestode and trematode parasites and suggested possible relationships between these parasitic worms and the fish population. The late Dr. H. J. Van Cleave, University of Illinois, identified the acanthocepha- lan; Professor R. V. Bangham, College of Wooster, iden- tified the nematode; and Professor M. C. Meyer, Uni- versity of Maine, identified the leech. 1946:20. to increase in the host warmouth until the fish dies. Extremely heavy infestations of metacercariae were found commonly in Park Pond warmouths over 5 inches in length, but seldom in smaller ones. The bass tapeworm, Proteocephalus am- bloplites (Leidy), was present in all war- mouths examined from Park Pond. As a plerocercoid larva, it occurred in most of the internal organs, especially in the liver, gonads, and mesenteries. Since the war- mouths acquired these parasites by eating copepods containing the procercoids, the rate at which the fish acquired the para- sites declined as the fish changed their food preferences from Entomostraca to larger items. Therefore, unlike Posthodiplosto- mum, plerocercoids did not occur in rela- tively greater numbers among the large warmouths than among the small ones at Park Pond. An interesting nematode, Camallanus oxycephalus Ward & Magath, lives in the lower intestine of the warmouth. Blood- red worms of this species were so numer- ous in some warmouths from Park Pond that they often formed tangled masses in the lumens of the guts. Frequently Cammal- 66 Intinors NATuRAL History SurvEY BULLETIN lanus worms were seen hanging as a red tuft from the anus of a fish taken from the water. Camallanus attaches to the inner intestinal wall. The warmouth serves as the final host, and infestation may take place at any time. The only parasite which infested no- ticeable numbers of warmouths from Ven- ard Lake was a leech, I/linobdella moorei Meyer. During the autumn and winter of 1948, leeches of this species were present in such large numbers that they appeared as compact fringes on the fins of the war- mouths. The caudal fins of the fish were severely damaged, frequently suffering ex- tensive destruction of the rays. Although the infestation was still heavy during the spring of 1949, only relatively few of the leeches were seen during the following summer months. An examination of 25 ovaries from war- mouths taken from Park Pond on No- vember 12, 1949, revealed the following: (1) 14 ovaries contained one or more par- asites; (2) ovaries of all sexually mature females were parasitized; (3) 24 plero- cercoids of Proteocephalus ambloplites oc- curred in 12 ovaries, as many as 4 in 1 ovary; (4) 27 metacercariae of Posthodip- lostomum minimum occurred in 10 ova- ries, 12 in 1 ovary; and (5) 4 sexually undeveloped adult acanthocephalans, Lep- torhynchoides thecatus (Linton), were found in 4 ovaries (1 in each ovary). In spite of these parasites, no sterile fish were found and no primary damage to the ovaries was evident. Warmouths were collected in sufficient numbers from Venard Lake and Park Pond to permit tentative conclusions to be drawn relative to the influence of para- sites on the general physical condition of these fish. Warmouths from Venard Lake had fewer internal parasites and a consist- ently higher coefficient of condition (C) than had warmouths of similar sizes taken from Park Pond. At the same time, among the heavily infested warmouths of Park Pond, no positive relationship could be shown between a fish’s coefficient of con- dition and the number of parasites present. Therefore, it is believed that the difference in condition of warmouths from the two lakes was more directly a result of differ- ence in densities of the total fish popula- tions than of parasitism. Vol. 27, Art. 1 Even though no harmful effects of para- sites on the condition (C) of warmouths in Venard Lake or Park Pond could be demonstrated, possibilities of some other harmful effects must be recognized. Fe- male warmouths from Park Pond pro- duced much smaller numbers of eggs than did Venard Lake females, table 16, which were less heavily infested. BEHAVIOR Observations on the behavior of the warmouth are scattered through many sec- tions of this publication. For example, the aggressive behavior of the nesting male is described (page 43) under “Spawning” in the section on reproduction. It seems de- sirable to bring together here certain as- pects of observed behavior of the war- mouth, although to do so will mean some repetition. General Activity and Disposition The warmouth has a quiet disposition; it moves around relatively little and dis- plays no showy activity except during the nesting season. It seeks the cover of weed masses, stumps, or rocky banks (pages 6 and 8), and avoids intense light. Reproductive Behavior Tinbergen (1953:23) describes syn- chronization, persuasion, orientation, and reproductive isolation as functions of mat- ing behavior in animals. These functions, along with defense of the nest area, the spawning act, and parental care, are con- sidered here as reproductive behavior in the warmouth. Defense of the Nest Area.—The nesting warmouth male displays an aggres- sive threat toward other fish that approach his nest area (page 42). He assumes a bel- ligerent attitude by swimming toward the intruder with his mouth open and his opercles spread ; at the same time, his eyes become red and his body becomes light yel- low in color. As the nesting male nears the intruder, he usually turns abruptly to one side or upward and, with vigorous movements of his tail fin, forces small pulses of water toward the intruder. He may also nip the intruder. The entire | | August, 1957 threat attitude associated with defense of the nest area is similar to the persuasive behavior employed by the nesting male in courting a female (page 43). Synchronization.— The spawning pe- riod for warmouths extends over several months (page 43). Male warmouths be- come ready to spawn earlier and remain capable of spawning later in the season than do females. Thus, a ripening female generally encounters many males ready to spawn. More precise synchronization for the actual discharge of sex products is brought about by the preliminary court- ship and persuasive gestures of the male and finally by the thump given the male as the female extrudes a group of eggs (page 44). Orientation.—The special orientation for mating in warmouths consists simply of the male having an established nest, the female with ripening eggs wandering into the vicinity of the nest, and the male initi- ating the persuasive actions. A signal— such as sound, odor, or color display, used by many animals to attract a mate from considerable distances—is not known to be given by the male warmouth. However, the female probably receives some internal physiological stimulus to wander as her eggs ripen and they become free for dis- charge. Persuasion.—The male warmouth’s threat attitude, described above, serves to initiate the action for persuading the fe- male to spawn. A female that is not ready to spawn responds to the threat as any other intruder would and is driven from the nesting area (page 43). On the other hand, a female that is ready to spawn quietly submits to the aggressive male. The threat, in which the male spreads his opercles and shows some display of color, is followed by attempts to guide the female to the nest depression. With only mild re- sistance and casual reluctance, the ripe fe- male accepts more and more of the male’s actions and soon enters the nest to remain with him for periods of time that become increasingly longer until spawning actu- ally takes place. The Spawning Act.—The series of signals and responses described above cul- minates when the male and female come together to deposit their sex products si- multaneously. Although the aggressive at- Lartmore: Lire History oF THE WARMOUTH 67 titude of the male makes it seem that he is controlling the spawning activities, the fe- male enters the nest only when she is ready, she gives the final signal (thumping the male’s side) for extrusion of eggs and milt, and she leaves the nest depression for short intervals between egg laying. The spawning signals and responses follow a definite sequence; it is interesting to recall that a female warmouth in a laboratory spawned alternately during one continu- ous spawning sequence with two male warmouths (page 44). After having been brought to a spawning attitude by one male, the female then responded to either of the two nesting males. Reproductive Isolation. — Hybrids are produced between the warmouth and a great number of the species of Lepomis, and yet such hybrids seldom occur in large numbers in natural populations. What forms the reproductive isolation that pre- vents greater hybridization was not de- termined in this study. There is little spa- tial separation of the various sunfishes. The warmouth is usually found living and even nesting with several species with which it could genetically hybridize, and yet few hybrid individuals are formed. In the absence of any other observable isolat- ing barrier, the isolation appears to result from a lack of the specific signals and re- sponses necessary to bring a warmouth to successful spawning with an individual of another species. In the laboratory, male warmouths have courted green sunfish and bluegill females but have not succeeded in spawning with them and seldom are able _to guide them to the nest depressions. Ap- parently, the series of specific signals and responses is not followed through to suc- cessful spawning. Parental Care.—After the warmouth fry leave the nest area, they receive no parental care. In ponds and lakes, the fry scatter into dense weed masses (page 48), and thus it becomes impossible for the male parent to keep the young together for close care. Protection afforded by the dense weed masses eliminates most of the needs for parental care. The male warmouth seems to lack the drive to care for his free- swimming young; even in a laboratory aquarium without vegetation in which the young may hide, he shows little interest in his fry after they leave the nest. 68 Group Behavior The warmouth is not a gregarious fish, even though large numbers of individuals may be concentrated in a comparatively small area. The following observations concern the social relations among war- mouths. Agégregations.—There is no_ school formation among warmouths except that immediately associated with the nest (page 48). Aggregations form around desirable cover, such as the riprapping along a dam (page 8), but little social structure can be detected in such groups. Even during the winter, when many fishes form groups, warmouths show no tendency to gather together except in response to choice hab- itats. The nesting colonies that have been reported (page 42) are probably due to restricted nesting habitat rather than to a gregarious nature of the species. Hierarchy.—To what extent an order of dominance occurs in a natural war- mouth population has not been observed. Attempts at observations on dominance are hampered by the difficulty of identify- ing individual fish in a natural setting; also, the order of dominance becomes com- plicated by nesting behavior, mating ag- gression, feeding activities, and local move- ments. A hierarchy is quickly established among warmouths in a restricted group, such as that in an aquarium. ‘The aggressiveness of a fish, as for food or space, and the dom- inance of the fish relative to other mem- bers of the group, determine its position in the hierarchy. the more stable and definite the order of dominance appears. In groups of more than three or four, the order may change frequently. Nesting studies in the labora- tory revealed that a male in spawning con- dition tends to assume dominance over one not so sexually advanced (page 42). The attitude of aggression which initiates the breeding behavior temporarily affects any existing hierarchy. Witt (1949:34) discovered a definite hierarchy among five warmouths in an aquarium. He found no correlation be- tween the order of dominance and the errors the fish made in learning to distin- guish a worm on a hook from a worm that is free. ILt”tiIno1is NATURAL History SURVEY BULLETIN The smaller the group. Feeding Behavior Warmouths have a simple pattern of taking food. When a food item is sighted, the fish turns toward it, judges its accepta- bility as food, and then may move in quickly to snap it up. An unacceptable food item may hold the warmouth’s atten- tion for several minutes. tionless object picked up by a warmouth. Suction created as the warmouth quickly — Vol. 27, Art. 1 Seldom is a mo-_ | | ; opens its wide mouth aids in the capture © . of food. This suction causes a loud noise — when the fish gulps an item of food from the water’s surface and may be responsible for taking a considerable amount of detri- tus with the food. Learning Witt (1949:27) found that warmouths could learn to distinguish a worm on a hook from a free worm. As isolated indi- viduals, warmouths learned about as quick- ly as did bluegills and more quickly than did largemouth bass, but in groups the warmouths made more errors than did either largemouths or bluegills. Individ- uals of all three species exhibited a fair de- gree of learning, making the majority of their errors in the first two of the seven trial periods. After being penalized for making an error, the warmouth was not so cautious as the bluegill in its approach to a hooked worm. Warmouths do not seem so cautious in taking fishing lures or so quick in recogniz- ing artificial situations as most other sun- fishes. In ponds and in laboratory aquar- iums, warmouths were seen to strike re- peatedly at artificial lures without, ap- parently, becoming suspicious that the lures were unnatural. In an aquarium, a rest- ing warmouth, molested by a succession of lures dangled before its face, apparently was so undisturbed by the experience that it turned to snap at a lure more attractive: to it than the others. On several days at Ridge Lake, Coles County, Illinois, a fish- erman repeatedly hooked and released! what appeared to be the same large war- mouth by dangling a worm in front of an) old piece of tile. This warmouth may have learned, but, if so, its memory did not last from one fishing trip to the next. The warmouth’s gullibility toward baits : August, 1957 may be a desirable trait for a warm-water sport fish. ECONOMIC RELATIONS Warmouths attain their greatest im- portance as food and sport fish in the lower Mississippi River valley and states bor- dering the Gulf of Mexico. There they are commonly taken with live bait by cane- pole fishermen. In the midwestern and eastern states, warmouths usually are not taken in large numbers but are caught on a wide variety of baits and lures. Because of their gamyness and plumpness, they are attractive to most anglers. The Warmouth as a Food Fish The warmouth is now of little commer- cial value, partly because in most states its sale is illegal; where it can be legally sold, the warmouth is not an important food fish in comparison to the larger species now be- ing marketed. In North Carolina during the early part of this century the warmouth was taken in gill nets and other nets and sold throughout the year (Smith 1907:235). At Reelfoot Lake, Tennessee, in 1937, it was one of the seven sunfishes that as a group comprised approximately 10 per cent of the weight of the commercial catch (Kuhne 19394:58). Most people consider the warmouth an excellent table fish. At times, however, this fish may have a “muddy” flavor, which is generally blamed on its association with silt bottoms and muddy waters, but which is caused at least partly by the food organ- isms comprising its diet. Warmouths taken off silt-covered bottoms of Park Pond usu- ally had an excellent flavor; they were in- termediate between the bluegill and the largemouth bass in both flavor and texture of flesh. The Warmouth as a Sport Fish An early angling critic, Henshall (1903:59), was very enthusiastic about the warmouth; he wrote, “For its size, it is the gamest member of the family except the black-bass.”’ In a discussion following a paper by Lovejoy (1903:120), Henshall pointed out that this sunfish takes a fly LarimoreE: Lire History oF THE WARMOUTH 69 well, responds to almost any kind of bait, and is an excellent table fish. Evermann & Clark (1920:393), Baker (1937:44), Curtis (1949:266), and others have praised the fighting qualities of the war- mouth or have termed it “‘an excellent small game fish.” The value of the warmouth as a sport fish is enhanced by the wide variety of nat- ural and artificial lures that are effective in catching it. Through most of its range, the warmouth is taken more commonly on natural baits (earthworms, minnows, grasshoppers, crickets, or grubs) than on artificial baits. The yield to the warmouth fisherman, using either natural or artificial lure, is often restricted by the difficulty of work- ing the lure in close enough to weed masses, brush, and other dense cover to present it properly to the fish without get- ting the hook snagged. This difficulty in- creases during the summer as aquatic vege- tation grows rank. Floating lures, such as poppers, are effective during the summer, because they can be dropped in pockets of open water among water weeds—where the warmouths may be hiding, feeding or nesting—and then be lifted out without becoming entangled. Worm fishing with a long pole offers similar advantages in fishing for warmouths around dense vege- tation and heavy brush. Most Illinois fishermen believe that warmouths may be taken in greater num- bers during the spring and early summer than at other seasons. At the Pollywog Association property and at the flooded limestone quarries (Fairmount Quarries) near Fairmount, Vermilion County, good catches of warmouths are usually made in May and June but seldom later in the sum- mer—at least not on the artificial lures that are relatively effective during the ear- lier months. Most of the warmouths caught at Ridge Lake (Dr. George W. Bennett, unpublished creel records from Ridge Lake, Coles County, Illinois) have been taken during the first month of the - summer fishing season. Although the catch of warmouths at Lake Glendale (Dr. Donald F. Hansen, unpublished creel rec- ords from Lake Glendale, Pope County, Illinois) was distributed rather evenly in the period May through August in 1945, the catch of warmouths in 1946 was much 70 Intinors NarurAL History SuRVEY BULLETIN higher in April and May than during the summer months. No warmouths were taken at Lake Glendale during September in either year. ‘These records form an in- teresting contrast with the records of Ricker (1945:330) for Muskellunge Lake, Indiana, where a striking increase in the catch of warmouths occurred during September. Censuses of sport fishing reported by Ricker (1945) for three Indiana lakes show that warmouths were taken regu- larly by anglers but not in abundance. Lewis & English (1949:317) recorded only four warmouths taken during 6,513 man-hours of fishing in Red Haw Hill Reservoir, lowa, even though warmouths were fairly common in the lake. They sug- gested that the low catch was due to the difficulties of angling among the dense marginal vegetation of this lake. Kuhne (1939a:51) calculated a take of war- mouths at Reelfoot Lake, Tennessee, that amounted to 1.02 per cent by weight of the anglers’ catch for 1937. The combined catches of resident and non-resident fisher- men amounted to only 0.02 warmouth per hour (Kuhne 1939a:48). In a creel cen- sus for the period March 1 through Sep- tember 30, 1952 (Cobb 1953:21), war- mouths comprised 2.05 per cent of the weight of all fish taken by sport fishermen at Reelfoot Lake. Creel records for Illinois lakes show that the warmouth usually is not abundant in the anglers’ catches. In Onized Lake, Illinois, Bennett (1945:380-3) reported only 105 war- mouths caught during 7,526.9 hours of fishing in a period beginning in 1938 and ending in 1941. This catch represented about 0.01 warmouth per hour. Even though this species comprised 18 per cent of the total number of fish (6 per cent by weight) in the final census of 1941, it made up only 2.6 per cent by numbers (2.9 per cent by weight) of all fish caught in the period of study. Since only a few war- mouths were caught during a period when the other sport fish were being severely cropped in this 2-acre lake, one might have expected warmouths to replace the other fish of desirable sizes removed by angling. However, only 13 warmouths of 6 inches or more in length were recorded in the final census. Vol. 27, Art. 1 At Horseshoe Lake, Alexander County, in southern Illinois, 2 per cent of the fish- ermen’s catch during the summer of 1956 was composed of warmouths (Bruce ~ Muench, 1956, report to the Illinois De- — partment of Conservation and Southern Illinois University). At Venard Lake, 20 of the 101 war- mouths planted in this lake early in 1947 were caught by anglers later in the same year. This take represented about 20 per cent of the number of warmouths planted — but only 14 per cent of the total catch. About 52 per cent of the 240 largemouth ~ bass that had been planted with the war-— mouths were taken by anglers in 1947. In 1946 at Lake Glendale, in southern — Illinois, the percentage of warmouths in the anglers’ creel was not far be- — low the percentage of warmouths in the — total fish population. Warmouths were — first caught in Lake Glendale the third — summer after impoundment of the lake in 1940 and they increased in the anglers’ catches during each of three summers fol- lowing their first appearance (Dr. Donald — F. Hansen, unpublished creel records from _ Lake Glendale, Pope County, Illinois). In the last year of the 3-year sequence, warmouths comprised 4.5 per cent of the — total number of fish taken. When the ~ lake was drained and the fish population — censused, warmouths made up 6 per cent _ of the total number of fish and 5 per cent of the total weight; 57 per cent of the warmouths were over 6 inches in total length. Several central Illinois ponds that, as 4 part of the life history study reported here, ¥ had been stocked with warmouths pro- — duced hook-and-line yields that were low — in proportion to the populations of these fish. The exploitation rate from angling was proportionally lower than for most — / other centrarchids inhabiting these waters. Fly and plug fishermen caught relatively 4 few warmouths; most large catches of war-_ mouths from these stocked ponds were taken on live baits. | Warmouth populations in the creeks and — rivers in most parts of Illinois contribute very little to the creels of anglers. How- ever, anglers who fish a few of the streams of southern Illinois report the common oc- currence of warmouths in their creels. The warmouth is probably not abundant | August, 1957 enough in the Mississippi River from Ca- ruthersville, Missouri, to Dubuque, Iowa, to be considered of much importance in the sport fishery (Barnickol & Starrett 1951: 519). The Warmouth as a Laboratory Fish The warmouth is a desirable fish for laboratory experimentation. It is rela- tively easy to transport from the field and to keep alive in the laboratory. It is large enough to be easily handled and yet small enough to be accommodated in most aquar- iums. It has a quiet disposition, quickly be- comes adapted to laboratory conditions, and readily feeds on a wide variety of foods. In the laboratory, the warmouth will nest and spawn, apparently undisturbed by the presence of an observer. The wide va- riety of foods acceptable to it simplifies the task of keeping this fish for long periods in the laboratory. Such characteristics as its tolerance for low concentrations of dis- solved oxygen, its rapid color responses to excitement, and its unusual individual and group behavior present interesting prob- lems for study. The warmouth has been used in Natural History Survey laborato- ries in studies of food conversion, learning, group behavior, and marking techniques, as well as in studies reported in the pres- ent paper. The Warmouth in Artificially Established Populations Several combinations of species have been used by fisheries biologists in seeking to establish fish populations that will pro- duce and maintain good sport fishing in lakes and ponds. In some waters, the largemouth bass and bluegill have seemed to be suitable companion species (Swingle & Smith 1941:271). In many Illinois lakes, however, this combination has not proved satisfactory, as bluegills have tended to overpopulate the water (Bennett 1944:186). Lovejoy (1903:116—-7) considered the _ warmouth one of the three best species to be used in stocking small ponds in the south. He wrote, “It grows to much larger size than the bream, thick and fleshy, with large mouth, and is to some extent LarimMoreE: Lire History oF THE WARMOUTH 71 cannibalistic, but not enough so to make it objectionable. It will eat a few of its own young, but not enough to miss them —yjust enough to make the balance grow well.” The stocking of inland waters with war- mouths for sport fishing was begun before the turn of the century. Records indicate that the distribution of warmouths by state and federal agencies has been sporadic and probably never on a large scale. For ex- ample, an Oklahoma state agency distrib- uted 36,300 fingerlings in the calendar year 1935, and the United States Bureau of Fisheries distributed 53,160 fingerlings in the fiscal year ending June 30, 1936 (Earle 1937:16, 23). In the 12-month period beginning September 1, 1946, a Texas state agency distributed 134,345 warmouth fingerlings, and in 1947 the United States Fish and Wildlife Service distributed 20,348 warmouth fingerlings and 20 warmouths at least 6 inches in length (Tunison, Mullin, & Meehean 1949:55,58). The Fish and Wildlife Service distributed 64,040 warmouth fin- gerlings in 1949 and 710 in 1950 (Dun- can & Meehean 1953:5-6) ; 4,600 war- mouth fingerlings and 610 warmouths at least 6 inches long in 1951 and none in 1952 (Duncan & Meehean 1954:4—5). In Alabama, Swingle (1950:49-73) stocked 10 of 34 experimental ponds with warmouths in combination with large- mouth bass, bluegills, and other fishes. Seven of the 10 ponds containing war- mouths produced populations that were considered balanced and 3 produced popu- lations that were considered unbalanced. Warmouths comprised less than 6 per cent of the total weight of fish in all but 1 of the 10 ponds, a pond with a population judged to be unbalanced; in this pond warmouths made up 11.3 per cent of the weight. Bluegills far outnumbered the warmouths in each population. The relatively low proportions of war- mouths encountered (usually less than 10 per cent by weight, table 4) indicate that these fish have no tendency to become dominant at the expense of other kinds of fishes. However, even these low propor- tions may represent overcrowding for the warmouths themselves, as indicated by slow growth and the occurrence of a high percentage of small individuals reported in 72 I_tinois NATURAL History SuRVEY BULLETIN several censuses. Growth studies in IIli- nois indicate that as low a proportion of warmouths as 10.4 per cent by weight, found in Park Pond Slough (a weed- choked channel in Park Pond) may repre- sent overcrowding for these fish. Growth of warmouths in this channel was consid- erably slower than was that of warmouths in Onized Lake, just preceding 1941, when warmouths made up 6.5 per cent of the total weight of the fish population — (Bennett 1945:382, 397), and slower than that of warmouths in Lake Glendale just preceding 1946, when warmouths made up 5.0 per cent of the total weight (unpublished information from Dr. Don- ald F. Hansen of the Illinois Natural His- tory Survey). In Onized Lake, the fish population had been thinned by excessive fishing, and in Lake Glendale the popula- tion had been expanding during the 6 years following impoundment of the water. Experimental Species Combina- tions.—As part of a series of manage- ment experiments by the author, 17 ponds in central Illinois were stocked with war- mouths in various combinations that in- cluded largemouth bass, smallmouth bass, several pan fishes, and minnows. Because these experiments have not yet been com- pleted and because they are not an integral part of the life history study reported here, the stocking combinations are listed below with consideration given princi- pally to the early development of the pop- ulations and such factors as directly relate to the life history of the warmouth. Warmouths (Adults); Largemouth Bass (Fingerlings and Y earlings).—This combination of species and sizes was first tested in 3-acre Enright Pond over a pe- riod of 15 months. Sixteen adult war- mouths, 4 yearling largemouths, and 60 fingerling largemouths per acre were re- leased in May, 1947. Warmouths spawned the first summer, and both species pro- duced broods of young the second sum- mer. Growth of all fish was rapid; some of the first-brood warmouths attained lengths as great as 6 inches in a little more than a year. There was a desirable distri- bution of numbers in size groups of both species. Warmouths (Fingerlings and Adults) ; Largemouth Bass (Fingerlings and Vol. 27, Art. 1 Adults ).—Both species were introduced in — numbers and sizes simulating a “pyramid — of numbers.” This combination was tried — in Enright Pond after termination of the experiment described above; the popula- tion was established during the early fall months of 1948 with 90 fish of each spe- cies per acre. Moderate-sized broods of both species were produced the next sum- | mer, and in each of the seven following summers the population was studied. — The striking difference between what oc- curred in this warmouth-largemouth pop- ulation and what usually occurs in a blue- gill-largemouth population was that in the — Enright Pond population the bass success- — fully produced a brood each year and fish — of the companion species (warmouths in — Enright) never produced such large num- | bers of young that they dominated the pop- ulation. In 187 hours of recorded fishing © during the sixth summer (there were — fewer records for other years), 98 large- — mouths and 16 warmouths were caught — at a rate that averaged 0.6 fish per hour. — The number and sizes of fish of each spe- — cies in this population were more nearly — constant from year to year than in popu- lations started with fish of one size. Warmouths (Adults); Largemouth — Bass (Yearlings and Adults)—Venard Lake was stocked in 1947 with 32 adult — warmouths and 70 yearling and 5 adult © largemouths per acre. The growth and — competition for food in this population ~ have been discussed previously in this pa- — per. The bass gained an early dominance — over the warmouths; by the end of the third growing season, the lake was be-— coming overcrowded with bass. q Warmouths (Adults); Largemouth Bass (Adults). — Fifteen adult war- mouths and 22 adult largemouths per — acre were released in Reece Pond in May, 1949. This 2.5-acre pond was character- — ized by a large proportion of shallow water — and dense masses of aquatic vegetation — (Potamogeton foliosus). Both species of — fish spawned the first summer and they — produced broods in each of the 7 succeed-— ing years. The extensive vegetation per- mitted the survival of more young fish than could grow well in this pond. ; Warmouths (Adults); Largemouth Bass (Adults) Added 1 Year Later.—In April and May, 1948, approximately 20 August, 1957 adult warmouths were released in a l-acre pool above Venard Lake. They produced a large brood in the summer of 1948. The following spring about 20 adult large- mouths were added to the pool. A small brood of bass was spawned, and the young grew well; by the end of the summer they were feeding on small warmouths. ‘This combination and sequence of setting up the population allowed the warmouths to become well established, may have limited Larimore: Lire History oF THE WARMOUTH 73 of sport fishes—was investigated in three populations containing warmouths and largemouths. Three adult warmouths and 30 finger- ling largemouths per acre were released in June, 1952, in Parkhill Pond, a 3-acre pond which contained a large established population of the bullhead minnow, Pime- phales vigilax (Baird & Girard). When the study was terminated at the end of about a year, which included parts of Fig. 25.—Central part of Kearney Pond, McLean County, stocked with warmouths and largemouth bass. the size of the first bass spawn, and pro- vided small forage fish for the bass. Warmouths (Established Population) ; Largemouth Bass (Adults)—In June, 1951, Kearney Pond (2.5 acres), fig. 25, containing a small population of war- mouths, principally yearlings, was stocked with 5 adult largemouths per acre. In the following October, 20 more adult bass per acre were added, along with 40 finger- ling and adult warmouths per acre. The warmouths produced a _ moderate-sized brood in 1951. In 1952, the largemouths produced a large brood, the warmouths a relatively small one. This relative spawn- ing success of the two species was main- tained in each of the 3 following years, or until the study was terminated. Warmouths (Adults); Largemouth Bass (Fingerlings) ; Minnows.—The in- fluence of minnows—both as a forage item and as a predator on the eggs and fry two breeding seasons, there was an abun- dance of minnows, the bass and warmouths had grown exceptionally fast, and the warmouths had produced broods the first and second summers. The largemouths, which were 10 to 12 inches in total length early in the second season, did not produce a brood. Since the warmouths spawned successfully even though an abundant min- now population was present, it seems likely that the largemouths would have produced a brood the next year. In July, 1948, Lutz Pond contained a large population of several species of min- nows, the most abundant of which was the bullhead minnow. -This 1.5-acre pond was then stocked with 20 adult warmouths and 60 fingerling largemouths per acre. War- mouths spawned the first summer (1948) and produced a large brood; these young fish grew -rapidly. The warmouths pro- duced another brood (1949) before the 74 Ittrnors NATURAL History SuRVEY BULLETIN 2-year-old largemouths spawned in 1950. The minnow population declined rapidly during the third summer. Kearney Pond (2.5 acres) contained minnows (species unidentified) and dart- ers, Etheostoma nigrum Rafinesque, when it was stocked in June, 1949, with 10 adult warmouths and 46 fingerling largemouths per acre. The warmouths, minnows, and darters reproduced well in the first sum- mer. Growth of the sport fishes was good. The numbers of minnows and darters de- clined during the summer. In Parkhill Pond and Lutz Pond, two broods of warmouths were produced before the first spawn of bass. In all three ponds, the abundance of small forage fish provided food for the warmouths and largemouths, which grew rapidly; large- mouths provided some fishing the second summer; and a bass brood of moderate size was spawned the third summer in the presence of two broods of warmouths. Warmouths (Fingerlings and Adults) ; Minnows.—In August, 1948, 34 finger- ling and 14 adult warmouths per acre were introduced into Longworth Pond (2 acres), which contained a large population of fathead minnows, Pimephales promelas Rafinesque. The warmouths spawned suc- cessfully during the remainder of the 1948 season and again the following summer. The broods in both years were small; evi- dently the minnows had a depressive effect on the warmouth population. Warmouths (Adults); an Established Sunfish Population—Three experiments were conducted to see if a small number of warmouths could successfully reproduce and survive in an established population consisting of several species of sunfishes. Seven large adult warmouths were planted in a one-half-acre pond, Green Gravel Pit, which at the time (June, 1947) contained a population of bluegills, redear sunfish, green sunfish, and large- mouth bass. Only one warmouth (orig- inal stock) was recovered when poison was applied to the pond in August, 1948. The warmouths had failed to establish a brood during the two intervening spawning sea- sons. In November, 1949, Taylor Pond (2 acres) was stocked with 69 adult war- mouths per acre. A few weeks before, it had been stocked with 100 bluegill fin- Vol. 27, Art. 19 gerlings, 100 largemouth fingerlings, and — 15 largemouth adults per acre; a few adult green sunfish, longear sunfish, and bluegills also were added. The population was killed during the second spawning season — (June, 1951); two adults, each a half — pound in weight, were the only warmouths — recovered from a rather large sunfish pop- — ulation (337 pounds per acre). i Twenty-three adult warmouths were re- leased in June, 1952, in a 3-acre pond, McCarty, which contained a new but large population of bluegills and largemouth — bass. No young warmouths (definitely — identified ) were taken from this pond dur- ing the following 4 years. ; Warmouths (Adults); Redear Sunfish — (Adults) ; Smallmouth Bass (Adults and — Fingerlings).—This combination of spe- cies was tested in two ponds. In July, 1951, 2-acre Taylor Pond E (mentioned in connection with another ex- periment) was stocked with 21 adult war- — mouths per acre. These fish produced a — small brood in the same summer. In the following fall and spring, 10 fingerling — and 7 adult smallmouth bass and 17 adult — redears per acre were added. A small brood of smallmouths, a moderate-sized brood of warmouths, and a relatively large — brood of redears were produced in the — summer of 1952. Observations the next 2 years revealed — the following: The smallmouths produced a very small brood in 1953 and no brood in 1954. Growth of the original stock of bass was good, but growth of both the ~ 1952 and 1953 year classes was very poor. — The warmouths and redears reproduced ~ successfully each year and at first grew at — satisfactory rates; however, by the spring of 1955 there were relatively few over 6.5 inches in length. Sparks Pond (3 acres), fig. 26, was stocked with 22 adult smallmouth bass in ~ November, 1949. The following spring — the smallmouths spawned very successfully. — In June, 25 adult warmouths and 34 adult ~ redear sunfish were added to the popula- — tion of this pond. Both of these species re- produced, although the brood of war- mouths was quite small in numbers. | During the following 7 years, these ob- servations were made: Smallmouth bass of — the first brood (1950) did not grow well after the first summer. The bass spawned ~ August, 1957 Lartmore: Lire History oF THE WARMOUTH 75 Fig. 26.—South side of Sparks Pond, Woodford County, stocked with warmouths, redear sunfish, and smallmouth bass. each year, but the fingerlings disappeared before attaining 1.5 inches in length. The only successful brood of bass after the first was that produced in 1954, which came after the redear sunfish population had been reduced in numbers by poison ap- plied to part of the pond, a tremendous number of small sunfish had been lost over the spillway during a severe flood, and bass of the 1950 brood had become less nu- merous. Growth in this 1954 brood of bass was poor. The redear sunfish spawned very suc- cessfully each year. The original stock and the first brood grew very well. Broods produced later showed much _ slower growth. After the fourth year, there were very few redears over 6 inches in length, although redears of smaller sizes were nu- merous. The warmouth population was slow to develop. Warmouths spawned successfully each year, but the broods produced were small. However, by the fourth year war- mouths were numerous and had become large enough to be attractive to anglers. Warmouths; Largemouths; Bluegills (Adults of One Sex).—Four experiments Were set up in attempts to produce war- mouth X bluegill hybrids. Kearney Pond (mentioned in connec- tion with other experiments) contained a 4-year-old warmouth-largemouth popula- tion when 8 adult female bluegills per acre were added, July, 1955, in an effort to produce hybrids with the warmouths. No hybrids were found in the two spawn- ing seasons after the bluegills were added. Dunmire Pond (4.5 acres), fig. 27, was stocked in May, 1950, with 16 adult war- mouths, 19 adult male bluegills, and 100 fingerling largemouth bass per acre. In July, 1955, 10 more adult male bluegills per acre were added. “The warmouths and largemouths grew well, spawned success- fully each year, and produced good fish- ing. The male bluegills grew exception- ally large (1.2 pounds), but no hybrids were observed in the first 6 years after the pond was stocked. A shallow 3-acre pond on the Univer- sity of Illinois Golf Course near Savoy was stocked with 45 adult warmouths, 185 adult female bluegills, and 907 largemouth bass fingerlings. These fish were placed in the pond in two groups, one group in each of the summers of 1949 and 1950. In the third summer following the original stock- ing, a large brood of bluegills was pro- duced; one or more male bluegills must have been accidentally introduced in 1950. No warmouth& bluegill hybrids were col- lected from this pond. During the summers of 1949 and 1950, 19 adult warmouths and 59 adult male bluegills were released in Green Gravel 76 Intrnors NaturAL History SuRVEY BULLETIN Pit, mentioned in connection with another experiment. Broods of warmouths were produced in each of these two summers and the two following summers that the study was continued. The male bluegills built nests, but no warmouth bluegill Vol. 27, Art. 1 minnow population and grow well when they become large enough to utilize the minnows as food. Largemouth bass in a pond with war- mouths apparently grow faster and pro- duce better fishing than do smallmouth Fig. 27.—North arm of Dunmire Pond, Woodford County, stocked with warmouths, large- mouth bass, and male bluegills. hybrids were collected. This half-acre pond, in which a substantial warmouth population had been developed, should have offered a desirable situation for hy- brid production. General Conclusions About Spe- cies Combinations.—Several general conclusions may be drawn from the pre- liminary observations on these experimen- tal populations. Usually when sexually mature warmouths are released in a pond before the middle of August, they will pro- duce a brood the same summer. In estab- lished warmouth populations, a high pro- portion of each new brood is spawned so late in the season that the fish are too small in their second summer of life to reproduce then. Small numbers of war- mouths when introduced into a pond over- crowded with other sunfish seem unable to establish a population. Warmouths repro- duce successfully in the presence of a large bass in a pond with warmouths. There is little difference in growth rates be- tween warmouths that develop in a pond with largemouths and those that develop in a pond with smallmouths. Warmouths will not establish a large enough popula- tion to support angling and materially reduce the survival of young bass unless adult warmouths are introduced a year be- fore adult bass are added, or unless fin- gerling bass, instead of adults, are intro- duced with the adult warmouths. There is no assurance that hybrids will be produced when bluegills of only one sex are introduced into a warmouth popu- lation. SUMMARY 1. The ecological life history of the warmouth, Chaenobryttus gulosus (Cuv- ier), was studied intensively in two habi- August, 1957 tats of central Illinois: Venard Lake, a 3.2-acre artificial impoundment stocked only with warmouths and largemouth bass, and Park Pond, an 18-acre flooded strip- mine area containing a fish population of 36 species. [he intensive investigations in these two areas were supplemented by ob- servations in other habitats and by pub- lished records on warmouth habitats and populations. 2. Field observations and published rec- ords indicated that the warmouth is usu- ally associated with habitats characterized by soft bottoms and dense stands of aquatic vegetation. 3. In the water areas under observa- tion, small and medium-sized (less than 5 inches total length) warmouths remained in protected areas of shallow water throughout the year, whereas larger indi- viduals spent more time in deep, open wa- ters. 4. Laboratory experiments supported field observations demonstrating that war- mouths are able to survive in water having very low concentrations of dissolved oxy- gen. The critical oxygen tension observed was 2.5 cc. per liter at 20 degrees C. Tol- erance for low oxygen concentrations al- lows the warmouth to survive and grow in a wide range of habitats and to survive during periods of water conditions that are generally considered unfavorable to fish. 5. The food habits of warmouths from Park Pond and Venard Lake were studied through a 12-month period. In volume and frequency of occurrence, the various food items identified in warmouth stom- achs showed little similarity in the two areas, although crayfish and nymphs of mayflies, dragonflies, and damselflies were abundantly utilized at both places. Dur- ing the summer months, feeding activity was at a peak early in the morning; it practically ceased in the afternoon. 6. Postlarval warmouths observed in the laboratory fed first on protozoa and bacteria. There was a general increase in size of food items taken by warmouths of Park Pond and Venard Lake as the fish increased in size; the percentage of stom- aches that were empty was higher among large fish than among smaller ones. 7. In Venard Lake, warmouths and largemouth bass consumed about the same Larimore: Lire History oF THE WARMOUTH Vi kinds of foods, but differences in their feed- ing habits may have prevented extensive competition between these species. 8. Seasonal changes in appearance and weight of gonads indicated that the war- mouths collected from Park Pond and Venard Lake attained sexual maturity when between 3.1 and 3.5 inches total length and that fast-growing fish matured earlier in life than did slow-growing ones. Warmouths over 5.4 inches total length attained spawning condition earlier in the nesting season, and spawned over a longer period, than did fish of smaller sizes. Males matured slightly earlier in the season than did females. In central Illinois, the spawn- ing season for warmouths generally extends from mid-May through mid-August. 9. An estimation was made of the total number of eggs in ovaries of warmouths of different sizes, from different water areas, and taken at different times of year. Total egg counts ranged from 4,500 to 63,200 per ovary. Females from Park Pond consistently produced fewer eggs than did those from Venard Lake. 10. A month before the beginning of the spawning season, groups of developing eggs began moving away from the primor- dial egg-stock in sexually mature war- mouth females. There was a gradual with- drawal of eggs from the egg-stock through- out the spawning season. Ova in advanced maturation were resorbed if not spawned before the cessation of nesting. 11. In all instances of warmouth nest- ing observed in the field, the male con- structed the nest, usually near some pro- jecting object and on a bottom of loose rubble containing some silt and detritus. No colony formation was observed. 12. Sex recognition among warmouths observed in the laboratory was based ap- parently on behavior and response to court- ing. Males displayed temporary color changes during courtship and spawning. There was evidence that many males and females spawned two or more times dur- ing a summer; in some instances, more than one female contributed to the com- plement of eggs in a nest. 13. In the laboratory, incubation of eggs lasted about 34.5 hours at tempera- tures between 25.0 and 26.4 degrees C. Immediately after hatching, the prolarvae dropped to the bottom of the nest. The 78 ILLino1is NatuRAL History SurRvVEY BULLETIN yolk supply was exhausted in + days, and the larvae attempted feeble, poorly di- rected jumps. By the fifth day, they swam actively. They began feeding by the sev- enth day; considerable pigmentation had developed and the caudal fin appeared homocercal. The 15.7-mm. young were essentially like an adult in body form. 14. The mathematical relationship (in inches) between the anterior radius of a warmouth scale magnified 41 times (S) and the total length of the fish (L) was expressed by the equation: L=0.5278+ 1.048 S 15. In the populations studied, as the body length of the warmouth increased, the tail became relatively shorter; differ- ent mathematical relationships between standard length and total length were found for fish of various sizes. 16. The relationship of standard length in millimeters (L) to weight in grams (W) was expressed for 866 Park Pond warmouths by the equation: log W=-—4.49867+3.04902 log L 17. The coefficient of condition (C) for 866 warmouths from Park Pond showed no consistent seasonal cycle. Sea- sonal variations in condition were greater in warmouths between 3.3 and 4.2 inches than in larger fish. Coefficient of condition increased progressively with increase in size of fish. 18. The annulus was found to be a re- liable year-mark in the warmouth. War- mouths in Park Pond completed the 1949 annulus between April 7 and May 20. Warmouths in Venard Lake completed the 1949 annulus over a shorter period than did those in Park Pond, where ecological conditions in the habitat varied greatly. Dredging of the shore of Venard Lake during August, 1948, is believed to have caused the formation of a false annulus. 19. Females from Park Pond were con- sistently smaller than males of the same ages. The difference was small, however. 20. Age was determined for 1,063 war- mouths from Park Pond; it was found that fish of certain year classes had con- sistently grown more rapidly than others. Growth for all year classes was better in certain years than in others. 21. The 1946, 1947, and 1948 year classes in Park Pond showed different growth patterns for the summer of 1949. Vol. 27, Art. 1 The fish in each year class grew rapidly during May and June. Although growth continued through the summer for the younger fish, it declined rapidly after June for the 1946 year class. The 1947 year class showed a growth pattern inter- mediate between the earlier and later year classes. Growth rates were different for warmouths in different parts of Park Pond. 22. A comparison of length increments for the first and for later years of life showed that warmouths in Park Pond with the greatest length increment for the first year added to this length advantage the second growing season. Fish that grew slowly the first year showed a slight — growth compensation during the third year, although they did not overcome the length advantage held by the larger fish. 23. Three year classes, represented by 1,102 warmouths, were studied in Venard © Lake. Fish of the first year class spawned — in the lake grew faster than did those of © succeeding year classes. The length range in a single year class was greater during the first summer than in succeeding years. The average growth in length for war- mouths in their first 3 years in Venard Lake was similar to that for warmouths of comparable ages in Park Pond. 24. Warmouths in Park Pond were heavily infested with Posthodiplostomum — minimum, Proteocephalus ambloplites, and — Camallanus oxycephalus. Except for an ~ infestation of the leech, Illinobdella moorei, warmouths in Venard Lake were relatively free of parasites. No direct harm- ful effect of parasites was established. : 25. Laboratory and field observations — showed that the warmouth has a quiet dis- — position. In its reproductive and group © behavior, it is similar to other centrarchids, — but it displays certain behavioral char- — acteristics peculiar to the species. 26. Reports and field observations dem- — onstrated that the warmouth is caught on — a wide variety of baits and lures, and that warmouth fishing is best during the spring — and early summer months. The warmouth © has been praised by sport fishermen for its fighting qualities. It is a useful fish for laboratory experimentation. 27. That warmouths have no tendency to become dominant at the expense of other kinds of fishes was indicated by the rela- — August, 1957 LarirmoreE: Lire History oF THE WARMOUTH 79 tively low proportions of warmouths re- ported in fish populations of Illinois and other states. In 17 ponds in central Illinois stocked with 11 different fish combinations that included warmouths with other spe- cies—largemouth bass, smallmouth bass, and several pan fishes—warmouths tended to establish small broods each year without seriously restricting the reproduction or growth of companion species. LITERATURE CITED American Fisheries Society 1948. A list of common and scientific names of the better known fishes of the United States and Canada. Am. Fish. Soc. Spec. Pub. 1. 45 pp. Bailey, Reeve M. 1956. A revised list of the fishes of Iowa, with keys for identification. Iowa Ag. Exp. Sta. Jour. Paper J-2914:325-77; a reprint of pp. 325-77 of lowa fish and fishing, 3rd ed., by James R. Harlan and Everett B. Speaker, published 1956 for lowa State Conser- vation Commission, [Des Moines], 377 pp. Bailey, Reeve M. (Chairman) 1952. [Report of] Committee on Names of Fishes. Am. Fish. Soc. Trans. 81(1951) :324-7. 1953. [Report of] Committee on Names of Fishes. Am. Fish. Soc. Trans. 82(1952) :326-8. Baker, C. L. 1937. The commercial, game, and rough fishes of Reelfoot Lake. Tenn. Acad. Sci. Jour. 12(1) :9-54. Bangham, Ralph V. 1939. Parasites of Centrarchidae from southern Florida. Am. Fish. Soc. Trans. 68(1938) : 263-8. Bangham, Ralph V., and Carl E. Venard 1942. Studies on parasites of Reelfoot Lake fish. IV. Distribution studies and checklist of parasites. Tenn. Acad. Sci. Jour. 17(1) :22-38. Barnickol, Paul G., and William C. Starrett 1951. Commercial and sport fishes of the Mississippi River between Caruthersville, Missouri, and Dubuque, Iowa. Ill. Nat. Hist. Surv. Bul. 25(5) :267-350. Beck, John R. 1952. A suggested food rank index. Jour. Wildlife Mgt. 16(3) :398-9. Bennett, George W. 1943. Management of small artificial lakes: a summary of fisheries investigations, 1938-1942. Ill. Nat. Hist. Surv. Bul. 22(3) :357-76. 1944. The effect of species combinations on fish production. N. Am. Wildlife Conf. Trans. 9 2184-90. 1945. Overfishing in a small artificial lake: Onized Lake near Alton, Illinois. Ill. Nat. Hist. Surv. Bul. 23(3) :373-406. Bennett, George W., David H. Thompson, and Sam A. Parr 1940. Lake management reports. 4. A second year of fisheries investigations at Fork Lake, 1939. Ill. Nat. Hist. Surv. Biol. Notes 14. 24 pp. Black, John D. 1945. Natural history of the northern mimic shiner, Notropis volucellus volucellus Cope. Ind. Dept. Cons., Div. Fish and Game, and Ind. Univ. Dept. Zool., Invest. Ind. Lakes and Streams 2(18) :449-69. Breder, C. M., Jr. 1936. The reproductive habits of the North American sunfishes (family Centrarchidae). Zoologica 21(1) :1-48. Carlander, Kenneth D. ; 1950. Handbook of freshwater fishery biology. Wm. C. Brown Company, Dubuque, Iowa. 281 pp. 1953. First supplement to handbook of freshwater fishery biology. Wm. C. Brown Company, Dubuque, Iowa. Pp. 277-429. Carlander, Kenneth D., and Lloyd L. Smith, Jr. 1944. Some uses of nomographs in fish growth studies. Copeia 1944(3) :157—62. Carr, A. F., Jr. 1940. Notes on the breeding habits of the warmouth bass. Fla. Acad. Sci. Proc. 4(1939): — 108-12. Clark, Frances N. 1925. The life history of Leuresthes tenuis, an atherine fish with tide controlled spawning habits. Calif. Fish and Game Comn. Fish. Bul. 10. 52 pp. Cobb, Eugene S. 1953. The status of commercial and sport fishing on Reelfoot Lake. Prog. Fish-Cult. 15(1) :20-3. Curtis, Brian 1949. The warm-water game fishes of California. Calif. Fish and Game 35(4) :255-73. [ 80 ] August, 1957 Larimore: Lire History oF THE WARMOUTH 81 Duncan, Lee M., and O. Lloyd Meehean 1953. Propagation and distribution of food fishes for the calendar years 1949-1950. U. S. Fish and Wildlife Serv. Statis. Digest 28. 38 pp. 1954. Propagation and distribution of food fishes for the calendar years 1951-1952. U. S. Fish and Wildlife Serv. Statis. Digest 32. 36 pp. Earle, Swepson 1937. Fish culture is big business in the United States. Prog. Fish Cult. 31:1-29. Elder, David E., and William M. Lewis 1955. An investigation and comparison of the fish populations of two farm ponds. Am. Midland Nat. 53(2) :390-5. Evermann, Barton Warren, and Howard Walton Clark 1920. Lake Maxinkuckee: a physical and biological survey. Ind. Dept. Cons. Pub. 7. Vol. 1. 660 pp. Fish, Marie Poland 1932. Contributions to the early life histories of sixty-two species of fishes from Lake Erie and its tributary waters. U. S. Bur. Fish. Bul. 47(10) :293-398. Forbes, S. A. 1903. The food of fishes. Ill. Lab. Nat. Hist. Bul. 1(3):19-70. 2nd ed. Forbes, Stephen Alfred, and Robert Earl Richardson 1920. The fishes of Illinois (2nd ed.). Illinois Natural History Survey, Urbana. cxxxvi “i S97 pp- Hall, Gordon E., and Robert M. Jenkins 1953. Continued fisheries investigation of Tenkiller Reservoir, Oklahoma, during its first year of impoundment, 1953. Okla. Fisheries Res. Lab. Rep. 33. 54 pp. Harper, Francis 1942. The name of the warmouth. Copeia 1942(1) :50. Hennemuth, Richard C. 1955. Growth of crappies, bluegill, and warmouth in Lake Ahquabi, Iowa. Iowa State Col. Jour. Sci. 30(1) :119-37. Henshall, James A. 1903. Bass, pike, perch and others. Macmillan Company, New York. 410 pp. Hile, Ralph 1941. Age and growth of the rock bass, Ambloplites rupestris (Rafinesque), in Nebish Lake, Wisconsin. Wis. Acad. Sci., Arts, and Letters Trans. 33:189-337. Holl, Fred J. 1932. The ecology ,of certain fishes and amphibians with special reference to their helminth and linguatulid parasites. Ecol. Monog. 2(1) :83—107. Hubbs, Carl L. 1919. The nesting habits of certain sunfishes as observed in a park lagoon in Chicago. Aquatic Life 4(11) :143-4. 1943. Terminology of early stages of fishes. Copeia 1943(4) :260. Hubbs, Carl L., and Gerald P. Cooper 1935. Age and growth of the long-eared and the green sunfishes in Michigan. Mich. Acad. Sci., Arts, and Letters Papers 20(1934) :669-96. Hubbs, Carl L., and Karl F. Lagler 1947. Fishes of the Great Lakes region. Cranbrook Inst. Sci. Bul. 26. 186 pp. Huish, Melvin Theodore 1947. The foods of the largemouth bass, the bluegill, and the green sunfish. Master’s thesis, University of Illinois, Urbana. 35 pp. Hunt, Burton P. 1953. Food relationships between Florida spotted gar and other organisms in the Tamiami Canal, Dade County, Florida. Am. Fish. Soc. Trans. 82(1952) :13-33. James, Marian F. 1946. Histology of gonadal changes in the bluegill, Lepomis macrochirus Rafinesque, and the largemouth bass, Huro salmoides (Lacépéde). Jour. Morph. 79(1) :63-91. Jenkins, Robert M. 1953. Growth histories of the principal fishes in Grand Lake (0’ the Cherokees), Oklahoma, through thirteen years of impoundment. Okla. Fish. Res. Lab. Rep. 34. 87 pp. Jenkins, Robert, Ronald Elkin, and Joe Finnell 1955. Growth rates of six sunfishes in Oklahoma. Okla. Fish. Res. Lab. Rep. 49. 73 pp. Jordan, David Starr, Barton Warren Evermann, and Howard Walton Clark 1930. Check list of the fishes and fishlike vertebrates of North and Middle America north of the northern boundary of Venezuela and Colombia. U. S. Commr. Fish. Rep., 1928, part 2. 670 pp. 82 Inuinois NaTuRAL History SurveEY BULLETIN Vol. 27, Art. 1 Katz, Max, and Donald W. Erickson 1950. The fecundity of some herring from Seal Rock, Washington. Copeia 1950(3) :176-81. Kuhne, Eugene R. 1939a. The Reelfoot Lake creel census. Tenn. Acad. Sci. Jour. 14(1) :46-53. 1939). Preliminary report on the productivity of some Tennessee waters. Tenn. Acad. Sci. Jour. 14(1) :54—60. Larimore, R. Weldon, Leonard Durham, and George W. Bennett 1950. A modification of the electric fish shocker for lake work. Jour, Wildlife Mgt. 14(3) :320-3. Lee, Rosa M. 1912. An investigation into the methods of growth determinations in fishes by means of scales. Counseil Permanent International pour |’Exploration de la Mer. Publications de Cir- constance 63. 35 pp. Copenhagen. Lewis, William M., and Thomas S. English 1949. The warmouth, Chaenobryttus coronarius (Bartram), in Red Haw Hill reservoir, lowa. Iowa State Col. Jour. Sci. 23(4) :317-22. Lovejoy, Samuel 1903. Fish on the farm—what species to select. Am. Fish. Soc. Trans. 1903:116-25. McCormick, Elizabeth M. 1940. oe 154 Floricultural Pathology: .......... 158 Identification and Extension....... 159 Pas amis We resenitcn apcuowits cieocctste nes 160 Uneolveds -Problemss)..<~ +40 -025.. -2' 160 Future Posstbilities..¢ S222. ¢s56 whe 161 PIG UAC Ss EOLOGY = ante nee ete onto rese 163 Beginning of Aquatic Ecology....... 163 First Hield Laboratory: 4 fre oi. 20. 165 Fishes: and: Planktont. ssc ose enc 166 The Fashes ‘of Tilimois snc ee kente 02 on 167 Uline River Plankton) <2.) 5... 167 Bottom F auma.c tees ate ees 168 New. inesvot Research® 2. 20.5. . >. 169 Early Management Attempts........ 170 Modern Management.............. 170 The Last: Ewenty, Yearse.) <0 aac: 172 Direction of Future Studies........ Way) Wounoiine RESBARGH:. J.)ir54",// \ erates 179 ID emelopment © s..0 cewayacats eee 179 Orennizationncns:.. ale? Ack see 181 Research Contributions: 2...4 es os: 183 Bids Fo Me sau sacs ee eee 183 Viamiima [siete eke cate 195 Wildlite, Management... v2.2... 4. 198 aes UtULe ener as aes hae ee 199 PUBLICATIONS AND PusLic RELATIONS. 202 Karly. Publications. sit? sen 5oee = oe 203 PublicakionsepeLiess tte «> case ws ee 205 Editorial’ Personnel yi: oh cssnc deco: Geert 207 Public selations. > socecc tee) whee BOO Paitocial Palicyce 446 2: are ato ste 208 PON AR Alec Oye Ei a i ate Nad Oa a a 210 che Library at Notmale.t..5.5...2 210 ‘he “Library ae; Urbana 2 ch eck est 210 Library: Collections... (2.22% ..a% se 211 (Cibrary *Petsomel sea: ae soe els Migancial .SUPPOLE? teece. Halee eee eee ForMER TECHNICAL EMPLOYEES....... 215 LLEERA TUR DE OULED. con a seach Se 219 *‘punoiSa10§ Ifa] Fy} UT UMOYS de Burpjing aorasas sj} pue asnoyusei3 [eJUeWIadx9 ay fT, “Surpling ay} jo Jy;eyYy ysam ay} Jo jsour Adnov0 Aaaing AiO SIP] [BANIEN STIOUT[[] Fy} FO Sat1OJe10Ge] PUB SIdyJO UIeW AYT, “OST Ul SSuUIM OM} 9y} ‘OPHT UI pajajdwiod sem Burpying ay} jo jaed jerjued oyy ‘usredwieyD-eueqig ul sndwied sioul[y FO AjIsIaAtUs) ay} UO BUIP[INgG SadInosay [eINJeN Fy} SurMoys ‘yjnos ay} Woz ‘MaTA [eILIIY “ gigigiggy | From 1858 to 1958 ee mid-point of the nineteenth cen- tury in the United States was marked by ferment, by excitement, by great ideas. River traffic was at a peak; rail- roads had been built and were being ex- tended. New areas were becoming more easily accessible to settlers. The point of departure to the exciting and mysteri- ous Far West was on the Mississippi River, and two things happened just before 1850 which focused attention on that vast and largely unexplored area —the movement of the Mormons from Nauvoo, Illinois, on the banks of the Mississippi, to the Great Salt Lake, and the discovery of gold at Sutter’s Mill in California. The United States tried its muscles in the Mexican War in its first inter- national conflict since its last test with England, and it ended Mexican domi- nance in California with the assistance of the Bear Flag Revolution. Politically the young country was go- ing through the series of events which ultimately led to the Civil War. On August 27, 1858, the most important of the Lincoln-Douglas debates, according to the estimate of some historians, took place at Freeport, Illinois. This debate is said to have won for Judge Douglas the Senatorship in his contest with Lin- coln, but at the same time it lost the Presidency for the Judge in a later con- test with the same adversary. At the debate, there was a boy of four- teen who wormed his way to the front of the crowd and gained some renown by vocally taking issue with Douglas at one point in this historically climactic discussion. “The youngster was consider- ably chagrined by reproof from _ those around him, but perhaps he was caught by the character of that meeting, for it is reported by George W. Smith (1927: 410) that There was much confusion—some real dis- order. . . . It appears from the reports that orators, reception committees, invited guests, and newspaper reporters all engaged in a AKL OW, .B.-M TL Es hand-to-hand conflict for seats and in cases for standing room. some This boy who had the courage to chal- lenge Judge Douglas was Stephen Alfred Forbes, later to be the person most re- sponsible for the development of the Illinois State Natural History Survey, the centennial of which this number of the Bulletin commemorates. Not only was this point in history one of swift movement and of critical impor- tance in the politics and development of the country; it also brought science into clearer focus. Many scientific societies were organized. Darwin’s Origin of Spe- cies appeared in 1859. Scientists were just beginning to play with the idea that their field was not a mental toy, that it could be put to practical use; and some scientists were announcing that they were interested in the practical application and popularization of their knowledge, much to the distress of most of their colleagues. As an illustration, there is a rather long apology which Walsh (18684:9) felt con- strained to include in his First Annual Report of the Acting State Entomologist. Apparently this comment was written for the eyes of Walsh’s scientific confreres; In part it says: In a Memoir intended for publication in the Proceedings of some grave Scientific So- ciety, it would, of course, be highly indecorous to break the dreary monotony of scientific hair-splitting by a single remark, which had the slightest tendency towards exciting that convulsive movement of the midriff, which the vulgar herd of mankind call “laughter.” . Four hundred years ago Martin Luther said, that ‘he could see no reason why the Devil should run away with all the good tunes.” I can see no reason, in the year 1867, why the pestilent yellow-covered literature of the day should monopolize all the wit and humor. If there is one thing which I have at heart more than another, it is to popularize Science—to bring her down from the awkward high stilts on which she is or- dinarily paraded before the world—to show how sweet and attractive she is when the frozen crust, in which she is usually en- veloped, is thawed away by the warm breath of Nature— ... If I merely succeed in en- ticing away a single young woman from her [85] 86 I~ttinois NAturAL History SURVEY BULLETIN mawkish novelettes and romances into the flowery paths of Entomology, or if I can only induce a single young man, instead of haunt- ing saloons and lounging away his time at street-corners, to devote his leisure to study- ing the wonderful works of the Creator, as exemplified in these tiny miracles of perfec- tion which the people of the United States call “bugs,” I shall think that I have not written altogether in vain. The growth of the population of Illi- nois resulted in the bringing together, within the state’s boundaries, of people with common interests in natural history. This field of knowledge had not gone un- noticed in this general geographical area, but the investigators here were individuals and worked pretty much alone. Just across the Wabash River to the east, Thomas Say had earlier done research on insects and other animal groups. Across the Ohio River to the south, John James Audubon had studied birds. NATURAL HISTORY SOCIETY Because by mid-century people inter- ested in natural history had become more numerous in the state, Cyrus Thomas of Carbondale was able to propose to the December, 1857, meeting of the State Teachers’ Association in Decatur that a Natural History Society of Illinois be formed (Bateman 1858a). The next year, on June 30, 1858, the Society was organ- ized at Bloomington in the office of the Illinois State Normal University (Bate- man 18584:258-9). It was given official sanction and notice when it was chartered by an act of the state legislature ap- proved February 22, 1861 (Illinois Gen- eral Assembly 1861:551-2). Immediately after its organization the new Society began the development of a museum and the collection of scientific literature. Among its active members mentioned by Forbes (1907c:893-4) were C. D. Wilber, who later became a consulting mining engineer; Dr. J. A. Sewall, who later became President of the University of Colorado at Boulder; Major J. W. Powell, who was to gain renown as an explorer in the West; Dr. George W. Vasey, for many years botanist with the United States Department of Agricul- Vol. 27, Art. 2 ture; A. H. Worthen, head of the first Illinois State Geological Survey; Cyrus Thomas, Benjamin D. Walsh, M. S. Bebb, Dr. Oliver Everett, James Shaw, Dr. Henry M. Bannister, Dr. J. W. Velie, Professor J. B. Turner, Dr. Ed- mund Andrews, Dr. Frederick Brendel, and Newton Bateman. The above list in- dicates a great breadth of interest and no lack of intelligence on the part of the — original members of the Society. The first officers of the Society included a General Agent, among whose duties were the collection and exchange of speci- mens (Batemen 18584:258). C. D. Wil- — ber was named to this office. The Society’s — original constitution (Bateman 1858): © 258) and the revised constitution of 1859 (Francis 1859b:662-3) provided that all specimens should be deposited in the Museum of the State Normal Uni- versity. The constitution as revised on June 20, 1859 (Francis 18594:662-3), dropped the General Agent, gave most of his du- ties to a newly created Superintendent, and added a Curator, whose duties were to receive and arrange specimens. Cyrus Thomas, who was elected Curator, lived in Jackson County, many miles from the Museum, and the elected Superintendent, ~ Wilber, who taught geology at the State Normal University, according to Mar- shall (1956) acted as unofficial curator. At the 1860 meeting, R. H. Holder of Bloomington was named both Curator and Treasurer (Wilber 1861a:538). The state charter of 1861 gave the Society authority to establish its own Museum at the State Normal University (Illinois General Assembly 1861:551), and officers of the Society set December 25, 1861, as the date on which the Mu- seum was to be “dedicated, with appro- priate exercises, aS € FREE OFFERING TO — THE CITIZENS AND SCHOOLS of Illinois” (Wilber 1861c:675). Forbes (1907c:893) listed Sewall, Powell, Vasey, and himself as curators — of the Society's Museum, Vasey serving — only nominally as Powell’s deputy. Powell — was named Curator by the State Board of — Education on March 26, 1867. on the same day by the Directors of the Natural History Society (Bateman 1867: His ap- — pointment was ratified and consented to | | _ December, 1958 tor of the MILts: 8). Forbes was appointed to the same office on June 26, 1872, the day Powell’s resignation was offered and_ accepted (Bateman 1872:6). Because the Natural History Society was composed principally of people who were prosecuting natural history investi- gations as sidelines to other activities, and because it was not a strong cohesive agent, it finally reached the point where it could no longer sustain itself. Forbes (1907c: 898) said of the times, “It should be remembered, in this connection, that this was a time when college men, as a rule, worked like dray-horses and were paid like oxen, De The Society turned to the state for aid, and by an act approved February 28, 1867, $2,500, to be paid annually to the State Board of Education, was appropri- ated by the General Assembly for the salary of a curator and “for the necessary expenses of improving and enhancing the value” of the Museum (Illinois General Assembly 1867:21). Major Powell was the first curator to receive state aid. The state appropriations, according to Forbes (1907c:895), “were largely drawn upon to outfit and maintain the Powell expedi- tions to the far west.” As a condition upon receiving further state aid, as pro- vided by legislative act approved April 14, 1871, the Society had to turn its Mu- seum over to the state (Illinois General Assembly 1872:152). On June 22, 1871, the Society agreed to the transfer and when, on June 28, 1871, the Board of Education accepted the transfer, the Mu- seum officially became state property (Bateman 1871:9; Forbes 1877 :324-5). On December 15, 1875, the State ‘Board of Education passed the following resolution (Etter 1876:17): Resolved, That we regard the Museum as a State institution, devoted to the prosecution of a natural history survey of the State, to the encouragement and aid of original research, and to the diffusion of scientific knowledge and habits of thought among the people. Forbes, who in 1872 had been appointed by the State Board of Education as Cura- Museum, remained in that capacity until July 1, 1877, when by legis- lative act approved May 25, 1877, a State Historical Library and Natural History Museum were established at Springfield, Irom 1858 ro 1958 87 and the I1linois Museum of Natural His- tory at Normal was “converted into a State Laboratory of Natural History” (Illinois General Assembly 1877:14—-6). STATE LABORATORY OF NATURAL HISTORY The act that established the State Laboratory of Natural History relieved Forbes of the necessity of developing mu- seum exhibits and allowed him to turn more of his attention to research. Shortly after the establishment of the Laboratory, Forbes’ title was changed from Curator to Director (Etter 1877:25). Forbes had not been occupying his time completely in the preparation of museum material while he was Curator of the IlIli- nois Museum of Natural History. He had taught classes in zoology at Illinois State Normal University and he had started a series of bulletins reporting on research and investigation. The first number of the series is dated December, 1876, and carries the title, Bulletin of the Tanats Museum of Nigiucel History. From the appearance of No. 2 of the first volume, in June, 1878, until the beginning of Volume nae in 1918, the title was the Bulletin of ae State Laboratory of Natural History, and from that time to the present it has been the Bulletin of the Illinois State Natural History Survey or Illinois Natural His- tory Survey Bulletin. ‘The volumes have been numbered serially from December, 1876, to the present time. The work of the Laboratory and its young Director attracted the attention of the new Illinois Industrial University at Urbana. Not only had Forbes been pub- lishing actively, but in 1882 the duties of State Entomologist had fallen on his capa- ble shoulders. Shortly afterward the Uni- versity made an offer of employment to the Director of the Laboratory and State Entomologist. Forbes faced the choice of declining the offer, of abandoning the Laboratory, which had been established at the Illinois State Normal University by legislative act, or of moving the Labora- tory with him. Apparently at his suggestion, the mat- ter was taken up with the State Board of Education by the Trustees of the Illinois Industrial University, and an agreement 88 was made that the law be changed to allow for the move. In a report addressed to the Regent and dated December 12, 1884. Forbes made known his needs at the University (Burrill 1887a:10). He stated: As you are doubtless aware, I have for some time held the position of Director of the State Laboratory of Natural History, lo- cated in the Normal University building at Normal, and, indeed, still remain in nominal charge of that establishment, having received from the State Board of Education a leave of absence, without pay, from January 1 to June 30, 1885, in order to enable me to enter upon my duties in the University here. If I believed that my acceptance of a chair in this University necessarily involved an inter- ruption or serious modification of the work which I have organized as Director of the State Laboratory of Natural History, I should keenly regret it; and, indeed, I did not ex- press my acceptance of that position until I had arranged a plan of readjustment which I thought adequate to prevent such a con- tingency. Later in the same meeting, Trustee Alexander McLean offered the following resolutions (Burrill 1887a:18) : Resolved, That the Trustees of the Illinois Industrial University have heard with great satisfaction the suggestion that the State Lab- oratory of Natural History may be united with the University under their charge. Resolved, That in case such a union shall be accomplished they will, to the extent of the means intrusted to them, aid in carrying forward the valuable work of the laboratory, by assigning to it suitable apartments in the building of the University, and by providing such conveniences as the nature of the work may require, to the end that it may enjoy a commodious and perpetual home within, and the generous cooperation of, an institu- tion founded and maintained for the promo- tion of scientific research and the dissemina- tion of practical knowledge. Forbes officially took over his duties at Urbana on January 1, 1885 (Forbes 1886/:Lx). In the following March the Regent, Dr. Selim H. Peabody, had the following comment (Burrill 1887a:19-20) : The unsuccessful effort of three years ago to secure for the University the presence and aid of Prof. S. A. Forbes for the organization of the instruction of Zodlogy was renewed last year, and has been crowned with better fortune. Since the opening of the new year the Zodlogical laboratory has become an ac- tive agency in this department of physical science, and its success is well assured. A new interest has been aroused in this science. I~ttinotis Natura History SurvEY BULLETIN Vol. 27, Art. 2 The office of the State Entomologist has found a home, it is to be hoped permanent, where it naturally belongs. The governing — board of the Normal University has unani- mously resolved that the State Laboratory of Natural History should find its proper abode here at the State University, and has consented that the property peculiar to the work of that [laboratory] may be transferred — hither. This change requires only legislative action before it can legally go, as it has prac- tically gone into effect, and there appears to be little doubt that such action will be taken — during the present session. The legislature approved the action, and everything was legal. On July 1, 1885, the appointment of Forbes as Professor of Zoology and En- tomology at the University of Illinois (previously Illinois Industrial University) at an annual salary of $1,160 was ap- proved by the Board of Trustees, which also appointed Forbes Director of the State Laboratory of Natural History and authorized him to receive laboratory prop- erty transferred by the State Board of Education (Burrill 1887a:50). It is inter-_ esting to note the size of the Laboratory staff at that time. On September 8, 1885, the Trustees approved the following ap- — pointments (Burrill 1887a:55-6) : Entomological Assistants Thomas F. Hunt $40 a month — Clarence M. Weed $40 a month Botanical Assistant Charles F. Hart $45 a month Amanuensis Miss Mary J. Snyder $45 a month Services relating to botanical survey Prof. T. J. Burrill $300 for the year F. S. Earle $83 1/3 a month Such other miscellaneous assistants as might be required and within the funds available The State Laboratory of Natural His- tory continued under that name until — 1917; STATE ENTOMOLOGIST The rapid settlement of Illinois during the middle of the nineteenth century brought in a great number of agricul- turists. The country was new, and the breaking down of the original vegetation for the establishment of fields in which crops were grown brought about great losses from insects. These losses, while | December, 1958 MILts: seen and experienced, were not well un- derstood. Official entomology was born during this period. The agriculturists felt the need of assistance and cried out to the government for it. At the end of the Civil War, the Presi- dent of the young Illinois State Horticul- tural Society, John P. Reynolds, spoke vigorously on the subject at the December 19, 1865, meeting of the Society at Nor- mal. In his retiring address, Reynolds (1866:8) said: And, first, the appointment of a STATE ENTOMOLOGIST. The time has been in this State when it required some moral courage for any one to advocate the appointment and compensation from the treasury of an officer to look after the bugs, but I venture the opinion that there is no subject in which you, as amateur or professional horticulturists, have a more direct, immediate or larger pe- cuniary interest, than in Entomology— No one who has given the subject any atten- tion will question the truth of the statement that the people of Illinois are to-day many From 1858 ro 1958 89 millions of dollars poorer by reason of noxious insects; nor the additional statement that a very large proportion of this loss might have been averted by the labors of a competent Entomologist with a little means at his disposal. In 1866 the Horticultural Society, meeting at Champaign, passed the fol- lowing resolution (Deyo 1867:58) : Resolved, Vhat we most urgently pray the honorable legislature of our great state to appoint a State Entomologist, that Agricul- iurists and Horticulturists may not quite despair of ever overcoming the giant insec- tiforous [sic] difficulties in the way of suc- cess in their professions. As one eminently qualified, and the highest in his profession in the whole west, we most hopefully mention the name of Benjamin D. Walsh, of Rock Island. The Horticultural Society was not alone in this movement. At a meeting of the executive committee of the Illinois State Agricultural Society on January 3, 1866, G. W. Minier offered the following University Hall on the University of Illinois campus. This building, completed in 1874 and razed in 1938, was headquarters for the Illinois State Laboratory of Natural History and the Office of State Entomologist for a few years after they were moved from Normal to Urbana. 90 Ittinois NATURAL specific and forthright resolution (Reyn- olds 1868:18) : Resolved, That whenever a sum of fifteen hundred dollars ($1,500) shall have been obtained, by legislative action or otherwise, for an annual salary, this Board will then appoint a competent scientific man as State Entomologist. Resolved, That Mr. B. D. Walsh be and he is hereby appointed State Entomologist, sub- ject to the preceding resolution. The legislature listened to these pleas and in 1867 passed a law which author- ized the Governor, with the consent of the Senate, to appoint a state entomologist. The work of this officer was considerably handicapped. While he was voted a salary, he was given no work fund, and the first Hisrory Survey BULLETIN Vol. 27, Art. 2 three persons to hold the position main- tained their offices in their homes or in offices devoted to other purposes. The job was a difficult one, and Forbes (1915: 7-8) once rather facetiously wrote: He [Walsh] performed as well as he could his various duties of private, captain, colonel, adjutant, and major-general of this new force—and in two years he was dead. He had two successors enlisted for the war on precisely the same terms, the first of whom, Dr. Wm. Le Baron, of Geneva, Illinois, main- tained for five years the unequal contest, when he also died; and the second, Dr. Cyrus Thomas, of Carbondale, abandoned the field in despair after seven years of diligent sery- ice, going then to Washington for work in another department of science, where he lived to the good old age of eighty-five. I have sometimes wondered if his long survival was Benjamin Dann Walsh, State Entomologist, 1867-1869. December, 1958 Mitts: not largely due to his fortunate escape from an untenable situation. Forbes set out to disprove this conten- tion, and carried the duties, however with more help than his predecessors had, from 1882 to 1917, a span of 35 years. Let us now look at the four men who carried the title and responsibility of Illi- nois State Entomologist. Benjamin Dann Walsh Although the resolutions passed by the State Horticultural Society and the State Agricultural Society in 1866 mentioned specifically Benjamin D. Walsh as a potential State Entomologist, Walsh did not obtain this title without some compli- cations. An act providing for this officer was passed by the legislature and was approved on March 9, 1867 (Illinois General Assembly 1867:35-6). No ap- pointment was made at that time. How- ever, a special session was called on June 11 of the same year, and at that time the name of Walsh was presented for the Sen- ate’s approval. The session was called for specific purposes, of which the approval of an appointee as State Entomologist was not a part. Therefore, the Senate decided that constitutionally it could not act on this matter. Walsh acted as State Entomologist, without legal status, and with an assign- ment of $500 by the Horticultural So- ciety, until the legislature passed an act “for the relief of the state entomologist,” March 25, 1869 (Illinois General Assem- bly 1869:53-4). This act legalized what Walsh had been doing for nearly 2 years. It is interesting to note that Walsh’s first annual report was made to the Horticul- tural Society and not to the Governor, and was signed by Walsh (18684:3) as Acting State Entomologist. Walsh was a most interesting person. He was born in Frome, Worcestershire, England, September 21, 1808 (Weiss 1936:234). He was well educated, and, about 1830, received a Master of Arts degree from Trinity College, Cambridge, where he was a classmate of Charles Dar- win. He was married in England, and in 1838 he came to America. His wife had relatives in Henry County, Illinois, and he purchased a 300-acre farm in that part of the state. He operated the farm until FROM 1858 to 1958 91 1851, when he moved to Rock Island and entered the lumber business. He was not a politician, but in 1858, when he suspected that the city was being cheated by the city council, he placed his name in contention for alderman. His purpose was to get at the city’s books. This action did not endear him to some elements of the city, and his life was threatened. Undaunted, he went ahead with a successful campaign, exposed the frauds, and resigned. Although he had made a small collec- tion of insects in England, he publicly had shown no deep interest in entomology until January, 1860, when he lectured for 2 hours to the State Horticultural Society. Thereafter he contributed regularly to the Prairie Farmer and other agricultural journals. Further, in the proceedings of scholarly societies, he published several excellent scientific papers on insects. He collaborated with E. T. Cresson, A. R. Grote, and J. W. McAllister in the pub- lication of a monthly called the Practical Entomologist, which lasted for only 2 years, until September, 1867. In Septem- ber of the following year, Walsh and C. V. Riley started the American Entomolo- gist. On November 12, 1869, as Walsh was walking down a railroad track, busily engrossed in reading a letter, a train ap- proached. When he saw the train, he was too late to clear himself completely, and his left foot was badly injured. The foot was amputated, and to console his wife he said, “Why, don’t you see what an ad- vantage a cork foot will be to me when I am hunting bugs in the woods: I can make an excellent pin-cushion of it, and if perchance I lose the cork from one of my bottles, I shall simply have to cut another one out of my foot” (Riley 1869-70:65). He published an article exonerating the engineer from all blame in the accident. He appeared to be recovering well from the accident when suddenly he began to decline, apparently from some internal injury. He passed away on the 18th of November, 1869. William Le Baron In 1870 Governor John M. Palmer requested William Le Baron to take over the position left vacant by the unfortunate 92 Intinois NATURAL History SURVEY BULLETIN death of Walsh. This request was quite unexpected, for entomology was only an active side interest of this competent physician. Things which are half-said in history pique the imagination. We find that Dr. Goding (1885:123), in a biographical sketch of Le Baron, had the following to say: In 1870 two candidates appeared for the office of Illinois State Entomologist made va- cant by the untimely death of the lamented Walsh—Dr. Henry Shimer of Mt. Carroll and Mr. Emery of the Prairie Farmer, both of whom were well qualified for the position. For reasons that cannot be given at this time, Gov. Palmer refused to appoint either, but Vol. 27, Art. 2 named Dr. Le Baron for the place, taking him entirely by surprise. Le Baron was a native of North An- dover, Massachusetts, where he was born October 17, 1814. He came from a line of New England professional people; his father was a medical doctor and _ his maternal grandfather was Dr. Thomas Kittredge, a well known and highly re- spected surgeon of his day. Le Baron’s calling was decided at an early point in his life. After studying medicine under an uncle, Dr. Joseph Kitt- redge, he practiced for several years in his home town. Later he completed his medi- cal studies and was graduated from the William Le Baron, State Entomologist, 1870-1875. December, 1958 MILs: Harvard Medical College. In 1844 he moved to Geneva, Illinois, where he con- tinued a successful career as a physician. As a child he was greatly interested in nature, moving from ornithology to botany to entomology. In 1850, after 6 years in Illinois, he published his first article, a From 1858 ro 1958 93 way. He died on October 14, 1876. The excellence of his four reports is a measure of the high ability that Le Baron possessed. Cyrus Thomas The third State Entomologist did not attend college (Goding 1889:106). The Cyrus Thomas, State Entomologist, 1875-1882. treatise on the chinch bug, in the Prairie Farmer. This study was so exhaustive that Asa Fitch, the New York State En- tomologist, republished it in his Second Report. In 1865 Le Baron was made the entomological editor of Prairie Farmer. In the position of State Entomologist he labored diligently until his health gave competence Cyrus Thomas attained was the result of his own personal labors. He was a versatile and practical person. He was born in Tennessee, July 27, 1825, and his mother had hoped that he would become a physician. In 1849 he moved to Jackson County, Illinois; where he stud- ied law and taught school. In 1851 he 94 Intinois NaturAL History SurvVEY BULLETIN was admitted to the bar and was elected county clerk. About 1864 he dropped law and entered the ministry. For some time, Thomas had considered entering the field of science and, as evi- dence of his practicalness, in 1856 he de- liberately began the study of entomology as being a field which was inexpensive and in which there was an abundance of ma- terial close at hand upon which he could work. He became an authority on the Orthoptera. He wrote many articles on entomology, some of which he contributed to farm journals. From 1869 to 1874 he was associated with the federally sponsored Hayden Geo- logical Survey, paying special attention to the entomology and agricultural resources of the West. During this period he pub- lished many reports of entomological significance. In 1874 Thomas was elected to the Professorship of Natural Sciences at Southern Illinois Normal University, whereupon he severed his relationship with the federal survey. The next year, 1875, he was appointed by Governor Richard J. Oglesby to take the place of Dr. Le Baron as State Entomologist. Six re- ports were published by Thomas and his collaborators. On March 3, 1877, the United States Entomological Commission was authorized by Congress. Thomas found time, along with his regular work, to become a mem- ber of this Commission. Other members of the Commission were C. V. Riley and A. S. Packard, Jr. Thomas was not col- laborating with amateurs when he joined these two men on the Commission. Both were giants in the profession—names that still command respect. Riley was State Entomologist for Missouri, as well as a member of the Commission, and the real originator of entomological research in the federal government. Packard was a scholarly gentleman, a member of the National Academy of Sciences and other learned groups, and an author of note in his field. Thomas was a man of real capability, holding, as he did simultaneously, a pro- fessorship at Southern Illinois Normal University, the State Entomologist’s re- sponsibility, and membership on the his- toric federal Entomological Commission. Vol. 27, Art. Thomas was interested in many things, and in July, 1882, he resigned his various Illinois positions and accepted employ- ment in the Smithsonian Institution’s Bu-. reau of Ethnology, leaving a brilliant and uncompleted career in entomology. He was to gain further laurels in archeology and to become an authority on the Mayan language. About some things he was adamant. He published a review of Darwin’s works from an orthodox view, which so im- pressed the officials of Gettysburg College that they hastened to award him an honor- ary Ph.D. degree. | Thomas lived to be 85 years old, pass- ing away on June 27, 1910. He bears a peculiar relationship to the Natural History Survey, for he is credited with having first proposed an I]linois Nat- ural History Society in 1857, and he was a State Entomologist. . Thomas was a man of multiple apti- tudes, as the above sketch indicates. He moved his intellect in many fields: school teacher, lawyer, county official, minister, entomologist, explorer, college professor, and archeologist. Stephen Alfred Forbes No one has molded the character of the Natural History Survey so much as Dr. Forbes, a man of irrepressible intellect and insatiable curiosity, and the fourth © and last Illinois State Entomologist. Forbes was born of pioneer parentage on May 29, 1844, in Stephenson County, — Illinois. He was one of a large family. — His father died when he was 10, and a brother assumed the responsibility for an_ invalid mother, Stephen, and a younger — sister. Stephen attended district school un- — til he was 14, and his brother carried on his education for 2 more years. For a short time in 1860 he attended Beloit — Academy. He had an innate interest in — language, and on his own he learned to read French, Spanish, and Italian. ‘ When the Civil War broke out in © 1861, Forbes was 17. He joined Company ~ B, 7th Illinois Cavalry, in September of that year. He rapidly advanced from or- — derly to sergeant to lieutenant to captain, reaching the last rank when he was 20. In 1862 he was captured while carrying dispatches near Corinth, Mississippi, and Mitts: December, 1958 From 1858 ro 1958 95 Stephen Alfred Forbes in the 1880’s, while State Entomologist and Director of the State Laboratory of Natural History at Normal. was in Confederate prisons for + months. During this period of enforced idleness he studied Greek from books he managed to buy at Mobile. He participated in 22 military engagements, and, other than suffering from scurvy and malaria while in prison, he emerged from the war unscathed. At the end of hostilities he entered Rush Medical College in Chicago. Be- cause of lack of funds and certain psy- chological difficulties revolving around surgery without anesthesia, he never fin- ished the course. After leaving Rush, he taught school and, on the side, studied natural history. His first publications ap- peared in 1870, and these led to his ap- pointment in 1872 as Curator of the Museum established by the State Natural History Society at Normal. He held this position until 1877, when he was appoint- ed to head the State Laboratory of Na- tural History, the child of the Museum. After the resignation of Thomas as State Entomologist in 1882, Governor Shelby M. Cullom appointed Forbes to that position. In 1884 Indiana University awarded Forbes the Ph.D. degree “‘by thesis and examination.” He did not have a bachelor’s degree. In 1885 he moved to 96 IttrNors NATURAL History SurRvVEY BULLETIN the University of Illinois, where he was Professor of Zoology and Entomology, Director of the State Laboratory of Nat- ural History, and State Entomologist. He was Professor of Zoology for 25 Vol. 27, Art. 2 he directed the first forest surveys of IIli- nois. These represent only a few of his innumerable interests. He was a member of many learned so- cieties and the recipient of many honors. Stephen Alfred Forbes in about 1915, shortly before being named Chief of the IIlinois Natural History Survey at Urbana. years, Professor of Entomology for 13 years, and Dean of the College of Science for 16 years. He was especially interested in the in- teractions of organisms and has_ been called ‘‘the father of ecology.” His inter- ests covered all of biology. He investigat- ed or directed investigations of the food of fishes and birds, the fishes of the state, and the biology of the Illinois River, and Beyond this, he was active in his church, helped organize the first golf club at the University, was a member of a _ hiking club, and late in life delighted in driving an automobile. On his eightieth birthday he was arrested for speeding, an incident which gave him some pleasure. When the State Laboratory of Natural History and the State Entomologist’s Of- fice were united in 1917 to form the Nat- 1958 MILLs: December, ural History Survey, Forbes became the first Chief of the new organization. He held this position until his death, March 13, 1930, when almost 86 years of age. The four sketches above cannot do jus- tice to the entomological pioneers who are their subjects, but they will give some indication of the high quality of the men. All were competent individuals with wes SP SK af The Natural History Building on the University of Illinois campus. From 1858 to 1958 97 the State Laboratory Bulletin by Uni- versity staff members. The State Entomologist’s responsibili- ties changed as time went on, and the agency became responsible for the admin- istration of some laws, as well as for research (Forbes 1909:64-5). With the discovery of the San Jose scale in Illinois in 1896, there was concern over the pos- About 1894 headquar- ters and laboratories of the Illinois State Laboratory of Natural History and of the State Ento- mologist were moved into this building. From July 1, 1917, until the middle of 1940 it housed the main offices and most of the laboratories of the Illinois Natural History Survey. high standards, even though they came from widely different backgrounds and possessed widely different trainings. (Among the sources of biographical material on Forbes are Anon. 1930, E. B. Forbes 1930, Ward 1930, Howard 1932, Van Cleave 1930, 1947, and Marshall 1956.) Reorganization Forbes administered the State Labora- tory of Natural History and the State Entomologist’s Office as a unit, inter- changing personnel and materials. Fur- ther, he made these agencies available to the University of Illinois in many ways, and considerable publishing was done in sible spread of other pests into the state. In 1899 legislation was passed giving the State Entomologist large powers in in- spection, certification, re quarantine. Other duties were added in 1907. According to Forbes (1909:55, 66), in 1909 the staffs of the two agencies con- sisted of the following: State Laboratory of Natural History Director Entomologist Zoological Assistants Artist Secretary Special assistants from time to time State Entomologist’s Office 1 State Entomologist Ree POR 98 InLInoIs NATURAL 10 Assistants 1 Draftsman 1 Chief Inspector 4 Temporary Inspectors 1 Foreman 12 Laborers Forbes’ interest was primarily in re- search and not in administering laws. During the reorganization of state gov- ernment under Governor Frank O. Low- den’s administration, the chance came to make changes which would bring Forbes’ interests into clearer focus. ‘Lhe State Laboratory of Natural History and the research activities of the State Entomolo- History SURVEY BULLETIN Vol. 27, Art. 2 gist were brought together in 1917 under a new name, the Natural History Sur- vey. This Survey was placed in the De- partment of Registration and Education along with the two other scientific sur- veys, Geological and Water. The admin- istration of quarantine laws and the like was transferred to the State Department of Agriculture. NATURAL HISTORY SURVEY We have followed the meanderings of organization from the Illinois Natural History Society of 1858 through the So- Theodore Henry Frison, Acting Chief, 1930-1931, Chief, 1931-1945, Illinois Natural His- tory Survey. December, 1958 Mitts: ciety s Museum to the Illinois State Lab- oratory of Natural History. We have also discussed the development of the State Entomologist’s Office from 1867 and have seen this office united with the State Laboratory in their research duties to form the State Natural History Sur- vey in 1917. A new type of administrative responsi- bility was set up in the Civil Administra- tive Code of 1917, which has remained essentially unchanged to the present time. The Code (Illinois General Assembly 1917:34) stated that: Unless otherwise provided by law, the func- tions and duties formerly exercised by the State entomologist, the State laboratory of natural history, the State water survey and the State geological survey and vested by this Act in the department of registration and education, shall continue to be exercised at the University of Illinois in buildings and places provided by the trustees thereof. Within the Department of Registra- tion and Education was established a Board of Natural Resources and Conser- vation; this Board is the responsible agent for the activities of the Natural History, Geological, and Water Surveys. The charge (Illinois General Assembly 1917:34) under which this group has worked through the years has been to 1. Consider and decide all matters pertain- ing to natural history, geology, water and water resources, forestry, and allied research, investigational and scientific work; 2. Select and appoint, without reference to the State civil service law, members of the scientific staff, prosecuting such research, in- vestigational and scientific work; 3. Co-operate with the University of IlIli- nois in the use of scientific staff and equipment; 4. Co-operate with the various depart- ments in research, investigational and scien- tific work useful in the prosecution of the work in any department. The Board consists of the Director of the Department of Registration and Edu- cation, who is chairman, the President of the University of Illinois or his repre- sentative, the President of Southern [Ili- nois University or his representative, a of whom are ex officio members, and, addition, experts in the fields of Doren, biology, ieee forestry, and engineer- ing who must have had a minimum of 10 years of experience in their professions. Expert members are appointed by the From 1858 to 1958 99 Governor and they have traditionally held long appointments. The biological scien- tists who have given or are giving of their time in this important state activity were or are William Trelease, John M. Coul- ter, Henry Cowles, Ezra J. Kraus, Carl G. Hartman, Lewis H. Tiffany, and Al- fred E. Emerson. The present Board consists of Director Vera M. Binks, Dean William L. Everitt (the representative of President David D. Henry of the University of Illinois), President Delyte W. Morris of Southern Illinois University, Dr. Walter H. New- house, Dr. Roger Adams, Mr. Robert H. Anderson, Dr. Lewis H. Tiffany, and Dr. Alfred E. Emerson. The Board meets quarterly, receives reports from the Chiefs, counsels with them on their research programs, appoints their scientists, and examines and approves their budgets. To return now to 1917: When the re- organization took place, Forbes, who was Director of the State Laboratory of Nat- ural History and State Entomologist, was retained as Chief of the Natural His- tory Survey. He remained as Chief until his death in 1930, and was extremely alert mentally uncil 9 days before his death. Not long after the turn of the century, Dr. J. W. Folsom of the University of Illinois Department of Entomology was walking down a street in Urbana when he discovered a youngster who was en- grossed in observing a colony of ants. Folsom engaged the boy in conversation and was impressed with his interest and knowledge. Thus began a close and per- sonal relationship between Dr. Folsom and young Theodore Henry Frison. Frison was born in Champaign, IIli- nois, on January 17, 1895, and was edu- cated in the schools of that city. Through Dr. Folsom he became acquainted with Dr. Forbes, and these two scientists al- lowed the boy to attend University courses prior to high school graduation (Campbell 1946). Frison was in the army for a short time in 1918, after which he returned to the University, which award- ed him all of his degrees. After short pro- fessional appointments in Wisconsin and New Jersey, and upon receiving his Ph.D. degree, he joined the staff of the Natural 100 Ittino1is NarurAL History SurvEY BULLETIN History Survey as Systematic Entomolo- gist. This was in 1923. Upon Forbes’ death in 1930, Frison was made Acting Chief, and on July 1, 1931, he was ap- pointed Chief. Frison was an indefatigable worker, becoming a_ specialist in bumble bees, Vol. 27, Art. 2 concluded that it would be essential that they attempt to obtain funds for a sepa- rate building. In this attempt they were successful. The University assigned an area for the building, and in 1940 the two Surveys began the move into a new Natural Resources Building, built for Leo Roy Tehon, Acting Chief, Illinois Natural History Survey, 1945-1947. aphids, and stoneflies. His tenure as Chief was marked by growth in staff and facili- ties. In the 1930’s the growth of his or- ganization was such that it was difficult to find space for the personnel in the rooms which the University could devote to use of the Natural History Survey. Dr. Frison and Dr. M. M. Leighton, Chief of the Illinois Geological Survey, conferred on the problems of space and their occupancy. The building, and subse- quent wings which were completed in 1950, were given to the University and added to that organization’s inventory. For the first time, the Natural History Survey had a home which it could really call its own. Frison had wide interests, and immedi- ately upon becoming Chief he began the development of wildlife research. “This a December, 1958 MILs: field, as a separate discipline, was new. He was instrumental in organizing the Midwest Wildlife Conference, the initial meeting of which was held in Urbana in 1935. Also he was a charter member of the Wildlife Society. The staff of the Natural History Sur- vey increased from 16 in 1930 to 38 at the beginning of World War II. In intellect and aggressive enthusiasm, Frison was a worthy successor of Forbes. He made many contributions to knowl- edge. He was a member of many learned societies and was given positions of re- sponsibility in them. Beyond that, he was a golf and tennis player, a fine violinist, and had a great interest in art, history, and current affairs. It was a loss to the Natural History Survey, and to science, when he passed away December 9, 1945, after 15 profit- able years as Chief. On December 10, 1945, Dr. Leo R. Tehon was appointed Acting Chief, a position which he held until February 28, 1947. Tehon was a meticulous scholar. He was not only a fine plant pathologist and mycologist, but also a good linguist and musician (Carter 1955, Ayars 1956). On March 1, 1947, Dr. Harlow B. Mills, the present incumbent, took over the duties of Chief. THE FUTURE Throughout its century of existence, this organization has attempted to meet the needs of the economy of Illinois with an eye to the state’s future requirements. The Board has appointed scientists with broad views and excellent training, men who were not satisfied with the present but who had a strong interest in the future. A half century. ago Forbes (1907c:892) wrote, “I shall be governed by the reflection that we are to-day look- ing forward and not back—that we are preparing for the future and not studying the past— ...” The same fresh view should govern us at the end of*100 years. The problems in nature are ever chang- ing, or, rather, our needs from and ap- proach to nature are ever changing. There are new demands and new approaches. New research techniques require re-eval- uation of what has been done. In agricul- From 1858 to 1958 101 ture there are new crops and new meth- ods of raising them. New plant diseases appear. New insect pests invade the state. New demands are made for recreation. New advances in pure scientific knowl- edge must be made. All of these demands and approaches require the attention of the research specialist. All are inextri- cably bound up in the future. A scientist who looks only to the past is professionally dead. Perhaps the greatest challenge of the future lies in the indisputable fact that human populations in the world — and that includes Illinois— are increasing. The demands which these people make on their environment are increasing more rapidly than are the people themselves! For most of our food and living room we are dependent on that surface which marks the boundary between the earth and the atmosphere, on that surface upon which the sun’s rays strike. We are de- pendent on it for our food and for our relaxation. More people mean greater food demand and greater need for remov- ing ourselves periodically from the intri- cacies of a complex civilization. More peo- ple mean a reduction in space for both of these necessities. This is the dilemma of the future. As the years roll by and the population statistics pile up, our de- pendence for existence on our living re- sources constantly becomes greater, and our dependence on the research scientist in fields of interest to the Natural His- tory Survey becomes a complete necessity. Now, in 1958, we are concerned about the great strides made by the physical sciences. These advances have great po- tential for good and tremendous potential for human destruction. International scientific competition has raised its head. If the deleterious side of this physical science development is kept in check, we can be sure that the need for sustaining humanity, both physically and spiritually, will be colossal in the years ahead. We hear in 1958 of “crash programs”’ to develop in the shortest possible time certain phases of physical science applica- tion. When the collective human popula- tion of the United States has to tighten its collective belt just one small notch, we will hear of a “crash program” the like of which has not as yet even been 102 Intinors NaturAt History SuRVEY BULLETIN Vol. 27, Art. 2 Harlow Burgess Mills, Chief, Illinois Natural History Survey, 1947 to date. conceived. And when that time comes, the Natural History Survey will be called on for even greater activity. In closing this discussion, it would be well to call attention to a House Joint Resolution introduced in the Seventieth General Assembly of the State of Illinois by Representatives Ora Dillavou, Charles Clabaugh, and Leo Pfeffer (Illinois House of Representatives 1957). The Resolution reads as follows: WuerREAS, On June 30, 1858, a group of far-sighted citizens of this State met at Bloomington and organized the Illinois State Natural History Society which was incorpo- rated in 1861 by an Act of the legislature; and WHEREAS, In 1877 the name of the so- ciety was changed to the State Laboratory of Natural History, and in 1885 the laboratory was moved to Urbana where it was placed under the direction of the Board of Trustees of the University of Illinois; and Whereas, The State Laboratory of Nat- ural History and the research activities of the State Entomologist’s office were united in 1917 to form the State Natural History Sur- vey Division of the Department of Registra- tion and Education; and Wuereas, The Natural History Survey has rendered outstanding service in the field of natural history, especially in regard to the control of noxious insects, the control of CE ee ee December, 1958 MILts: diseases attacking floricultural and ornamen- tal plants, the development of forestry in Illinois, the management of fishes in ponds and streams, the foods and movement of waterfowl in this State, the problems of up- land game species, and the periodic report of species which are especially endangered, such as the prairie chicken and wood duck; and Wuereas, The following world recog- nized scientists and scholars have been as- sociated with the wonderful work of the Natural History Survey: Stephen A. Forbes, Robert E. Richardson, David S. Jordan, | Frank C. Baker, Charles A. Kofoid, Robert Ridgway, Benjamin D. Walsh, Wesley P. Flint, Victor E. Shelford, Theodore H. Frison, and Leo R. Tehon; and WHEREAS, Since 1858 the Natural His- tory Survey has received wide recognition for its contributions to society, has gained the respect of scientists throughout the world, has brought considerable prestige to this State, From 1858 ro 1958 103 and, above all, has contributed immeasurably to the welfare of all the people of this State; and Wuereas, The 100th anniversary of the Natural History Survey will be celebrated in 1958; therefore, be it Resolved, By the House of Representatives of the Seventieth General Assembly of the State of Illinois, the Senate concurring herein, that this General Assembly, on behalf of all the people of this State, extend heartiest con- gratulations and sincere appreciation to the staff, members and employees of the State Natural History Survey Division, on the oc- casion of their 100th anniversary, for the outstanding contributions they have made to- ward the growth and development of this State; that we extend to them a wish for continued success and progress in the future, and that a suitable copy of this preamble and resolution be forwarded to the chief of the State Natural History Survey Division, Mr. Harlow B. Mills. Economic Entomology : HEN settlers moved into the I[lli- nois country, established homesites, and began to till the virgin soil, they found that hundreds of species of insects native to the area readily transferred their affections from wild plants to culti- vated crops, at times in hordes sufficient to destroy the crops completely. It was inevitable that the Illinois settlers, like the eastern colonists, had brought certain pests along with them. The hitch-hiking pests included the codling moth in apple barrels, the hessian fly in straw used as packing material, bedbugs in bedding, and lice on the bodies of the settlers. As if these were not enough, other migrants, such as the Colorado potato beetle, the imported cabbage butterfly, the cotton leafworm, the San Jose scale, the Nor- way rat, and the fleas thereon, invaded the area. They were followed in later years by such notorious insect pests as the oriental fruit moth, the European corn borer, the sweet clover weevil, the Mexi- can bean beetle, and the Japanese hee- tle. The early Illinois settlers were a hardy, self-sufficient, and determined lot, gener- ally not rich but for the most part thrifty and aggressive. They took pride in the fact that they were skilled in the agricul- tural arts of their day. At the same time, they admitted that the problem of coping with the many insect pests that damaged their crops, annoyed their livestock, and in- vaded their homes was beyond their com- prehension. They sought the aid of neigh- bors, school teachers, doctors, and local amateur naturalists, who in turn sought the counsel and advice of Fitch, Harris, and other entomologists located in the far-off New England and Atlantic coastal states. When these sources of informa- tion proved inadequate, the settlers ap- pealed to the state legislature to appro- priate funds and to appoint a state ento- mologist to study what appeared to be the most perplexing of all their problems. On February 27, 1867, the Illinois Gen- GEORGE C. DECKER® 4) eral Assembly created the office of State Entomologist. EARLY HISTORY E Pleasant surprises await the curious — who attempt to assay the extent and use-_ fulness of man’s knowledge of insects their habits, and control measures in the 1850’s and 1860’s. It is gratifying to note that local, self-trained entomologists such — as Walsh, Le Baron, Thomas, Shimer, — and Riley had collected and identified : hundreds of species and that they possessed — a remarkable knowledge of the life cycle and ecology of perhaps three-fourths of — the economic species ordinarily included in — any current list of noxious insects in the Midwest. Le Baron (1871:5-6) sum- marized the situation as he saw it at that time: : The history of many of our noxious insects, and especially the most notorious of them, has been pretty thoroughly traced, not only by the entomologists expressly employed by several of the States for this purpose, but also by many — other active gleaners in this field. Still, any — one who enters upon the study of this extensive — subject, soon finds work enough upon his hands. It cannot be said that the history of any insect is perfectly and absolutely known, and it is a notorious fact that some of the insects which have been longest known and studied, such as the Plum Curculio and the Apple Worm, are the very ones which are causing the most damage to the horticulturist at the present day; and if we take into account the multitude of insects which are preying upon our shade and ornamental trees and shrubs, which, in the estimation of many, are scarcely inferior in value to the fruit bearing trees, we may safely conclude that the prospect is very remote when the work of the practical ento- mologist will cease or materially diminish. And the force of this view is greatly enhanced by the [occurrence], every year, to a greater or less extent, of new species of noxious in- sects, or rather of insects which, having ex- isted here or elsewhere in moderate numbers, from time immemorial, have suddenly sprung into destructive profusion in consequence of an abundant supply of congenial food, or the ab- sence of their natural enemies, or other condi- tions favorable to life, some of which are known, and some of which are obscure or in- [ 104 ] December, 1958 : : : | : : DECKER: scrutable. The Colorado Potato-beetle, the Currant Saw-fly, the Asparagus-beetle, and the Bruchus granarius; to which we might add the Pear-caterpillar (Callimorpha Lecontei), and the Lesser Apple-leaf folder (Tortrix malivorana,) treated of in the following re- port, were all unknown here as noxious in- sects until within the last few years. It is true that some noxious insects, on the other hand, have greatly diminished, and some, which have been the sorest scourges of the orchardist, such for example, as the notorious Bark-louse of the apple tree, seem to be in the process of ex- tinction. Walsh and the others acquired much of their knowledge through their own ob- servations and experience, but obviously they were familiar with most of the world literature on the subject. Furthermore, it seems reasonably certain that then, as now, much unpublished knowledge on the subject was transmitted from individual to individual through correspondence and conversation, some of it even as tradition. We know that pioneer naturalists ob- tained considerable information from the Indians. For example, the English ex- plorer, Jonathan Carver (1778:493-4) wrote of his travels among the American Indians in 1766: I must not omit that the LOCUST [grasshop- per] is a septennial insect, as they are only seen, a small number of stragglers excepted, every seven years, when they infest these parts and the interior colonies in large swarms, and do a great deal of mischief. One may be more than a little sur- prised to discover that several local ama- teur naturalists—doctors, lawyers, college professors, orchardists, and agricultural- ists, never referred to as or considered to be entomologists—knew many of the common insects by name and possessed a knowledge of their biology and_ habits adequate to permit these men to engage in lengthy and intelligent discussions on the subject at meetings of agricultural and horticultural societies. For example, Dr. E. G. Mygatt (1855), a physician, wrote an essay, “Bark Louse of the Apple Tree,” for the first Transactions of the Illinois State Agricultural Society, 1853- - 54, and J. B. Turner (1859), a professor of Latin and Greek, presented a paper, “Microscopic Insects,” at the first meet- ing of the Illinois Natural History Soci- ety in 1858. It is interesting to note that at this time two men, Le Baron (1855) Economic ENTOMOLOGY 105 and Thomas (1859a), each one later ap- pointed to the office of State Entomolo- gist, were presenting papers on Illinois birds and other topics in the field of nat- ural history. In the light of these pleasant surprises, one is amazed to realize that the com- bined knowledge of all the experts was almost nil when it came to questions of practical control measures that could be employed to eliminate these pests or even to reduce materially the annual losses attributable to them. It is possible that the paucity of practical information can best be understood if we recall that for many years it was believed well-nigh sac- rilegious for a scientist to consider the practical application of his accumulated knowledge; as the distinguished Professor Louis Agassiz (1863:24) once said, “the man of science who follows his studies into their practical application is false to his calling.” Local and national repudiation of this philosophy contributed to the industrial and agrarian crusades that resulted in creation of state entomologists’ offices and land grant colleges. Touching upon the new philosophy of science and educa- tion in addressing the founders of the Illinois Natural History Society at their first meeting in 1858, Turner (1859: 647) said: In respect, also, to those grosser forms of vegetable and animal life, it seems to me that our research should in future aim more di- rectly at practical utility than in the past. We are quite too content with mere descrip- tion of forms and names, sometimes, without pushing our inquiries into the causes, relations and uses, and evils of things. We need not simply to christen ‘all these things—not simply to name the beasts, but also to rule over them, as did our great father Adam; and, also, all other forms of matter. And we cannot do this till we know minutely their history, habits and relations to other things and beings. The grand end to be aimed at, in reference to most forms of fungi and parasites of all sorts, is their prevention or destruction. But a vast amount of minute antecedent knowledge is needed before we can hope to say, “thus far and no farther,’ even to one single race or tribe, much more to the vast myriad of races and tribes. Benjamin Walsh, the first State Ento- mologist of Illinois, was in full accord with the views of Turner. In addressing 106 a meeting at Cobden, Illinois, in No- vember, 1867, he said: I do not regret to say that I belong to the modern school of science, and think it no deg- radation, so far as my specialty is concerned, to bring science to the aid of practical men in the related departments of human industry. And I need not tell you, for you know, that insects pick your pockets, and that to fight them successfully it is necessary to know their habits and how to distinguish friends from foes (Walsh 1868a:143). Cyrus Thomas subscribed to the new philosophy several years before he became State Entomologist. And the study of natural history is a useful study, having many direct practical advan- tages. Agriculture is the pedestal on which the stately fortunes of bankers and merchant kings are reared, and as the pedestal contracts or expands, so rises or falls the lofty column (Thomas 1859a:667). Therefore, we say, that natural history should be studied for the practical use made of the knowledge obtained. And, if it be a study so desirable and so useful, the question arises, Should not the study be generally intro- duced into our schools and colleges? I answer, most emphatically, yes! There is no other branch of physics, nor any branch of metaphysics so important and so necessary to be studied in the school room as natural his- tory. And I am glad to see that quite a num- ber of institutions have ventured to cross the Rubicon; yet others are halting at the brink, fearful of the result (Thomas 1859a:668). Thus, the first and third State Ento- mologists publicly expressed their views. They took office dedicated to the task of assisting the residents of the state of IIli- nois to find practical solutions for their numerous and complex entomological problems. Their successors followed the same course. PRACTICAL PROBLEMS AND PROGRESS Change is eternal in the insect world; thus, it appears that the need for contin- ued study of insects will never end. This situation may be confusing to laymen, but entomologists and others who have closely studied nature realize that insects are dynamic creatures subject to constant change in characteristics. Because of their great mutability, insects have sur- vived in an ever-changing world for mil- lions of years and are still capable of ILtLINois NatrurAL History SuRVEY BULLETIN making the necessary adjustments to many of the important changes in their — environment. Most of the important eco- — logical changes in an area or community are accompanied by changes in the insect fauna; some species drop out and others move in. Every agricultural practice adopted or discarded by man induces a significant en- vironmental change or modification which will favorably or unfavorably affect in- sects and, for that matter, all other living organisms in the area involved. Changes in crop rotations, fertilization practices, pruning, or drainage will prove favorable for some species and unfavorable for oth- ers. At the time the Office of State Ento- mologist was established in Illinois, fruit and vegetable crops could not be econom- ically produced and marketed in the state without reasonably effective insect con- trol. Since the high per acre value of such crops seemed to warrant expenditures for insect control, Illinois producers of these crops demanded and received a_ large share of the Entomologist’s time. As the nature and magnitude of insect losses in other agricultural and nonagricultural areas became more apparent and better understood, pressures from a multitude of other sources necessitated a realignment and much greater diversification of ento- mological research. Space will not permit enumeration and full discussion of all the insect problems that have arisen to plague Illinois farm- ers in the past century and it will not allow a detailed review of the thousands of printed pages that have been used to record the findings of research conducted during this period. Therefore, in the brief resumé that follows we confine our attention to a few specific examples. Fruit Insects In 1868 an editor of The American Entomologist, probably Walsh, sum- marized the fruit insect situation as fol- lows: : It is notorious among fruit growers, that the Curculio has now almost entirely vetoed the cultivation of the plum; and of late years this pernicious little Snout-beetle has extended its ravages to the peach, and even to the apple and pear, to say nothing of those rarer and Vol. 27; Arta y . fs “a i | e 3 a December, 1958 DECKER: choicer fruits, the nectarine and the apricot. The strawberry and the grape vine are in- fested by a host of insects, some of them known for many years back to science, others de- scribed and illustrated for the first time by the editors of this paper in various publications; while there are still others the natural history of which has never yet been published to the world, and which will be figured and described by the editors in the progress of this work. What with the Bark-louse in the North, the Apple-root Plant-louse in the South and the Apple-worm everywhere, the apple crop in North America is gradually becoming almost as uncertain and precarious as the plum crop (Walsh & Riley 1868a:1). To show that the testimony of an ento- mologist was not biased and that the con- ditions described above were more or less general, we may note a comment made by the eminent journalist Horace Greeley (1870:301): If I were to estimate the average loss per an- num of the farmers of this country from insects at $100,000,000, I should doubtless be far be- low the mark. The loss of fruit alone by the devastations of insects, within a radius of fifty miles from this city, must amount in value to millions. .. . We must fight our paltry ad- versaries more efhciently, or allow them to drive us wholly from the field. The first white settlers in Illinois ob- served that the native fruits—plums, grapes, haws, and berries—were subject to attack by a variety of insects. More than three-fourths of the species recog- nized as fruit pests today were recognized and mentioned in agricultural or hert:- cultural reports and farm journals prior to 1870. The plum curculio, for exam- ple, was to be found in every plum thicket and, when improved varieties of plums were introduced, the curculio took to them like ducks to water. In discussing plum culture at a fruit growers’ meeting in 1852, a Mr. Brewster reported that for + years the curculio had destroyed his plum crop. Then followed a general dis- cussion of proposed control measures, such as jarring, banding, paving, and using lime, soap suds, and chamber lye. The following year a similar report pro- voked a repetition of the members’ favor- ite control measures, but by then two gen- _tlemen had the answer: Just fence the plum orchard and turn in_ chickens (J. A. Kennicott 1855:296, 314-5). The idea of using chickens for control of curculio paralleled a suggestion made Economic ENTOMOLOGY 107 by a Mr. Harkness at a _ horticultural meeting in 1853: Some twelve years since, a neighbor of his en- closed a wild plum thicket, as a yard for swine; trees bore full crops every year; never troubled by curculio, whilst other thickets about had fruit nearly all destroyed by them. Four years since the hogs were turned out, and the ground appropriated to other uses; the first year after, the fruit was mostly destroyed by curculio (J. A. Kennicott 1855:314). Gradually certain members of the cur- culio tribe developed a liking for related stone fruits and even apples. In his first and only report as State Entomologist, Walsh (18684:64) noted: Although the Curculio now infests the culti- vated species of Plum (Prunus domestica, Lin- naeus,) to fully as great an extent as our com- mon wild species (Prunus americana,) yet it is only at a comparatively recent date that it attacked our cultivated Plums, and since that epoch it has been growing every year worse and worse, and making onslaughts upon other fruits, such as the Peach, the Cherry, and even the Apple. For 20 to 30 years the use of Hull’s curculio catcher or similar devices to jar curculios out of infested trees, so that the insects could be destroyed, and the use of hogs and chickens confined to the or- chards to consume infested fruits as they fell were the two principal, and perhaps the only meritorious, control measures. One should note, however, that farm journals carried glowing advertisements for numerous concoctions, which were almost worthless or which did more harm than good. The successful use of insecticides for the control of the plum curculio on peach and other stone fruits did not materialize until lead arsenate came into the picture in the late 1890’s, because the more solu- ble arsenic compounds—white arsenic, Paris green, and London purple—then available proved too phytotoxic for use on such delicate foliage as that of peach, plum, and cherry. With the aid of im- proved insecticide formulations, spray schedules, and equipment developed through years of continued research, IIli- nois orchardists were able to hold their own with the curculio until a crisis de- veloped during World War II. Then as labor and other overhead costs increased and lead arsenate became less effective, 108 many peach growers, after a few years in the red, pulled up their trees and aban- doned production. A hope that DDT would control plum curculio faded quick- ly, but BHC became available just in time to save the peach-growing industry. BHC was short-lived as an _ insecticide for plum curculio control; it was replaced by more effective and less objectionable materials such as chlordane, dieldrin, and parathion. However, it was BHC that saved the day for a number of orchardists. Orchards that could have been bought for a song, and a poor one at that, in the fall of 1946 and spring of 1947 were not for sale in 1948. After a century of research by the Nat- ural History Survey and its parent or- ganizations, we find the plum curculio is, for the moment at least, very well under control. Surveys conducted in 32 com- mercial peach orchards for the past 5 years showed that at harvest time less than 1 per cent of the fruit was infested or dam- aged by this weevil. Other insects of the peach that have required research attention include the oriental fruit moth, a group of sucking insects responsible for an injury known as catfacing, the peach tree borers, and at least three species of scale insects. For- tunately these, too, are successfully con- trolled by currently available measures. Even so, peach growers insist that the entomologist will have to find more eco- nomical control measures, or the high cost of producing peaches will put the growers out of business. The codling moth (mentioned by Walsh as the “Apple-worm’’), unques- tionably the No. 1 apple insect in Illinois, apparently arrived in eastern United States from Europe about 1800 and made its first appearance in Illinois about 1850. In 1869, while checking his theory that this insect had been a hitch-hiker in apple barrels, Walsh reportedly found about 200 cocoons in a single barrel. The cod- ling moth wasted no time in becoming adapted to its new environment. In the early transactions of the horticultural and agricultural societies and in pioneer farm journals, there are numerous references to the ravages of this insect. For example, in the first issue of The American Entomol- ogist in September, 1868, we read: [Ltinors NaturAL History SurvEY BULLETIN Vol. 27, Art. 2 i a < & Jotham Bradbury, residing near Quincy, IIL. has an old apple orchard, which many years ago used invariably to produce nothing but wormy and gnarly fruit. A few years ago he plowed up this orchard and seeded it to clover, by way of hog pasture. As soon as the clover had got a sufficient start, he turned in a gang of hogs, and has allowed them the range of his orchard ever since. Two years after the land was plowed the apple trees produced a good crop of fair, smooth fruit, and have continued to bear well ever since (Walsh & Riley 1868b:455). In the same article, further extolling © the value of hogs, we read: But the plum curculio and its allies are not the only insects that we can successfully attack through the instrumentality of the hog; neither is stone fruit the only crop that can be pro- tected in this manner. For the last fifteen years or so, pip fruit, namely, apples, pears, and quinces, have been annually more or less deteriorated by the apple worm or larva of the codling moth boring into their cores, and filling their flesh with its loathsome excrement (Walsh & Riley 1868):3). In addressing the Southern Illinois Fruit Growers Association in 1867, Pres- ident Parker Earle (1868:137) said: The curculio and the tree borers have been discussed at length in our former meetings, but the codling moth—which threatens us even greater damage than the curculio—has re- ceived little attention. There is some hope that great promptness and energy may save us from the terrible devastation which this moth has wrought in all the older States, and in the older fruit-growing neighborhoods of Illinois. Its damage to the apple crop of the country each passing year should be reckoned at mil- lions of dollars. From all sections we have the same sad story of “the apples dropping prema- turely’—“the apples mostly wormy”’—“the ap- ple crop used up,” by the codling worm. In many districts of the East where apples were once abundant they now entirely fail, because of the worms, and they not only threaten the destruction of the apple crop of the country, the whole country, but pears seem equally exposed. In many sections of the West nine-tenths of the pears are reported spoiled by the codling moth. The comments of Earle and other early horticultural leaders clearly establish the codling moth as the outstanding pest of apples in Illinois in the third quarter of the nineteenth century. From 1850 to 1870 the pasturing of hogs in the or- chards and the use of straw or cloth bands around the tree trunks to trap larvae for later destruction were about the only con- trol measures of established merit. Even December, 1958 DECKER: these measures were only partially effec- tive, and a large percentage of the apples harvested showed insect damage. In fact, the situation was so bad that the fruit judges at county fairs protested the ad- mission of fruit damaged by codling moth, and eventually a rule was passed that the unmistakable evidence of codling moth damage or the presence of San Jose scale disqualified a fruit for competition. In- secticides did not come into the picture until after the value of Paris green had been established for the control of the Colorado potato beetle and a number of other pests. In his third report as State Entomolo- gist, Le Baron (1873:17Z) recommended only cultural practices for control of the codling moth: . PRACTICAL TREATMENT. This may be reduced to the four following heads: Ist. Destroying the insects in their winter quarters. 2d. Picking the trees. 3d. Gathering the wormy apples from the ground, or letting swine and sheep have the range of the orchard. 4th. Entrapping the worms in bands and other contrivances. To which may be added the help to be de- rived from their natural enemies. In his previous report, Le Baron (1872:116) had mentioned the use of Paris green to control cankerworms on apple, and this may in part have led to the subsequent work by Forbes and oth- ers for control of codling moth on apple. We find but few references to trials with Paris green on crops in 1867 and the following decade. In 1880, however, with repeated warnings that suitable precau- tions must be observed, large-scale testing of Paris green and its companion, London purple, got under way. After 2 years (1885-1886) of experimentation, Forbes (1889:15) concluded: The experiments above described seem to me to prove that at least seventy per cent of the loss commonly suffered by the fruit grower from the ravages of the codling moth or apple worm may be prevented at a nominal expense, or, practically, in the long run, at no expense at all, by thoroughly applying Paris green in a spray with water, once or twice in early spring, as soon as the fruit is fairly set, and not so late as the time when the growing apple turns downward on the stem. wormy apples from the Economic ENTOMOLOGY 109 He presented data showing that, in 1885, 68 per cent of the unsprayed apples were wormy, whereas only 21 per cent of the sprayed apples were wormy, and, in 1886, 40 per cent of the unsprayed apples were wormy and 12 per cent of the sprayed fruit. When lead arsenate became avail- able about 1895, entomologists began ex- perimenting with it, and for the next 30 to 40 years practically all codling moth research centered around attempts to improve formulations and spray _ sched- ules involving the use of this chemical. Between 1915 and 1918, in seven sep- arate studies, Illinois entomologists found that in unsprayed blocks fruit ranged from 9 to 84 per cent wormy and aver- aged 45 per cent wormy, whereas in the blocks sprayed with improved lead arse- nate formulations the fruit ranged from 1 to 20 per cent wormy and averaged 4.4 per cent wormy. With what appeared to be a satisfac- tory control measure working reasonably well year after year, entomologists and fruit growers alike became more or less complacent, only to be shocked by a dou- ble-barrelled attack. The codling moth began to show evidences of resistance to arsenical sprays, and, as dosage rates and numbers of applications were increased, the United States Food and Drug Ad- ministration began to bear down on lead and arsenic tolerances. The next three decades might be characterized as a pe- riod of mad scramble for cover. Attempts were made to find (1) ways to remove spray residues, (2) suitable substitute materials, (3) ways to synergize insecti- cidal action without increasing residues, and (4) better sanitation and other non- chemical procedures. Research did well to hold its own, during this critical pe- riod, until DDT came into the picture at the close of World War II. The success of DDT in controlling the codling moth was spectacular, and within 2 years the growers’ clamor for more work on codling moth control faded. A review of research data and the re- sults of harvest surveys made the past 3 years show that now 33 to 94 per cent of the fruit in unsprayed apple orchards is wormy, approximately the same percent- ages as in the 1860’s, 1880’s, and the sec- ond decade of the present century. In 110 I~ttinois NarurAL History SURVEY BULLETIN contrast, we find that in sprayed orchards 0.03 to 7.6 per cent, or an average of 2.2 per cent, of the fruit is wormy. Thus, we find that, in spite of adversities and re- verses, continued research has developed control measures that have enabled apple growers to reduce the percentage of Vol. 27, Art. 2 a dozen important scale insects alone. One scale insect of great importance is the San Jose scale, which was introduced into California from China about 1880 and into Illinois about 1895. For a time this scale threatened to wipe out the IIli- nois commercial fruit industry. Parasites, Spraying equipment designed and used about 1897 by the State Entomologist and his assist- ants for experiments on control of San Jose scale. ‘The principal apparatus used is a large and complicated machine sprayer consisting of a one-horse power gasoline engine, a three-cylinder force pump, and a large double galvanized-iron tank with a powerful gasoline heater beneath for making the solution of whale-oil soap” (Forbes 1900:14). The sprayer was mounted on a two-horse baggage wagon. worm-damaged apples from possibly 60 to 100 per cent in 1867 to 21 per cent in 1885, 4.4 per cent in 1915, and 2.2 per cent in 1957. If it appears that entomologists have devoted too much attention to this one insect, let us recall that codling moth re- search has been the traditional guinea pig for the study of many insect control pro- cedures, and that the measures developed for the control of the codling moth for the most part have given satisfactory con- trol of a considerable number of other pests of apples. A list of the insects attacking fruit crops in Illinois would no doubt include 100 or more species. There are at least predators, and diseases have played an im- portant role in holding this insect at bay, but for over 50 years orchardists have found it necessary to apply a dormant spray or some other special treatment to bring this insect under control. As late as 1950, Illinois apple growers seemed to agree that if the use of sprays was to be forbidden San Jose scale would eliminate commercial orchards within 5 years. This insect, perhaps more than any other, has been responsible for the development of a strong plant inspection and quarantine system in Illinois, and, for that matter, in other states as well. Here we have an insect that can barely survive on wild or neglected trees but that thrives on young, =. GS December, 1958 DECKER: vigorously growing orchard trees—an ex- cellent example of how man creates, or at least aggravates, his own insect problems. The more man prunes and fertilizes, the more certain he is to develop a serious San Jose scale problem. Truck Crop Pests An article, probably by Walsh, pub- lished in 1869 makes it clear that at an early date a host of insects were recog- nized as important pests of a wide vari- ety of vegetable crops: There is scarcely a vegetable raised in our gardens that is not preyed upon by one or more grubs, caterpillars, or maggots, so that, when we eat it, we have positively no security that we are not mingling animal with vegeta- ble food. Two distinct kinds of maggots, pro- ducing two distinct species of two-winged Fly, burrow in the bulb of the onion. Scabby po- tatoes are inhabited by a more elongated maggot, producing a very different kind of two-winged Fly, and also by several minute species of Mites. Turnips, beets, carrots and parsnips are each attacked by peculiar larvae. And as to the multifarious varieties of the cabbage, not only are they often grievously infested by the Cabbage Plant-louse—a species which has been introduced from Europe into this country—but also by an imported cater- pillar producing a small moth, and by several indigenous caterpillars producing much larger moths, some of which caterpillars, when full- grown, are over one inch long (Walsh & Riley 1869:114). Why the article failed to include the corn earworm, the squash vine borer, the cucumber beetles, and the melon louse is hard to say, for they were numbered among the best known pests at the time. One is amazed that the Colorado potato beetle was not mentioned, because this species was the most spectacular insect pest of vegetable crops in Illinois in the latter half of the 1860’s. Presumably, prior to 1850 the Colorado potato beetle was unknown except as an _ interesting species found only in the foothills of the Rocky Mountains, where it fed on a wild potato somewhat resembling the common horse nettle. When the pioneers planted Irish potato and egg plant in Nebraska and Colorado, the beetle found these closely related plants to its liking, in- creased its numbers many fold, and took off for the East, flying from one settler’s potato patch to another’s. Here again we have an example of how man may create Economic ENTOMOLOGY 111 his own insect control problems. The in- troduction of a crop highly attractive to a native insect invites this insect to trans- fer its affections to the newly introduced crop. ‘The potato beetle transferred its affections from its native host to the in- troduced potato. It seems quite probable that the potato beetle’s many natural en- emies did not travel eastward but con- tinued searching for it in its old haunts. With an abundance of lush, nutritious potato vines and a temporary release from its natural control agencies, the Colorado potato beetle, in the vernacular of today, “went to town’ until a new system of checks and balances could be established. The eastward movement of the potato beetle was first noted in eastern Colorado in 1859. It did not appear in Illinois un- til 1864. Damaging populations of this beetle were reported in several Illinois counties in 1865. Some of the tales of wholesale potato destruction related in the local press and the Prairie Farmer were downright pathetic: “Let every man and woman in the country or in town, who has a potato patch, try experi- ments for the destruction of these pests and report progress. Something must be done to stop the destruction of the vines by these in- satiate creatures or we may as well quit trying to raise potatoes” (Cedar Valley, Iowa, Times, quoted by Riley 1866:432). I know of several cases near Rock Island, IIli- nois, where the owners of potato-patches, after persevering in a course of hand-picking for fully a month, finally gave up in despair, be- cause as fast as they killed off their own bugs, a fresh supply from their neighbors’ potato- patches kept flying in upon them (Walsh 1866:14). All accounts seem to agree that neither lime, nor ashes, nor any available external applica- tion is of the least use in checking the depre- dations of this insect. The Prairie Farmer says that “Mr. Jones found, after many experi- ments, that neither hot lime, lime-water, brine, tobacco-water, wine (?) nor sulphur had any effect on them; that turpentine, benzine and kerosene would kill them when copiously ap- plied, but also killed the potatoes,’ and that “coal-oil mixed with water is ineffectual.” . .. Although there is some contradictory evi- dence, yet the general result of all the testi- mony is, that neither domestic fowls, nor ducks, nor turkeys will eat them, at all events to any very extensive amount (Walsh 1866:14). Hand picking, or the manual collection and destruction of the beetles, their lar- vae, and their eggs, was about the only really effective control measure. During 112 [Ltinois NaruraAL History SurvEY BULLETIN the next several decades, it was said of many a farm boy who had risen to a prominent position, “He made his first dime collecting potato bugs on his grand- father’s farm’’—not his father’s farm, for there, in accord with the tradition of the Vol. 27, Art. 2 The value of predators and parasites was not overlooked, and at times differ- ent kinds of poultry, particularly turkeys, were noted as effective control agents. Hellebore, London purple, and calcium arsenate were later added to the list of Spraying equipment developed in recent years by entomologists of the Illinois Natural History Survey for the control of the corn earworm and the European corn borer on sweet corn and field corn. day, he performed the task without com- pensation as a member of the family. Many potato growers experimented with Paris green applied in several ways, and by 1870 dusting plants with a mix- ture of Paris green and flour or lime was quite generally accepted as the most ef- fective remedy available. However, there were many growers who were fearful of the poisonous properties of the arsenical compounds and they continued to place their trust in hand picking. Some grow- ers went so far as to design rather elab- orate mechanical devices which they mounted on skids and dragged up and down the rows to beat the beetles from the plants and collect them in pans, trays, or boxes, where the beetles could be de- stroyed. insecticides recommended for control of the Colorado potato beetle. As the potato leafhopper, aphids, blight, and other pests attracted increased attention, a variety of insecticide and fungicide combinations came into common use. Research pro- duced minor improvements in formula- tions and methods of application that en- hanced the effectiveness or economy of control measures, but there was no sub- stantial or basic change in control pro- cedures or practices until the advent of DDT in 1946. While potato growers and entomologists alike had been inclined to feel that the control measures in use in the early 1940’s left little to be de- sired, they apparently overlooked or gross- ly underestimated the damage inflicted by the insects, for within 2 years after December, 1958 DECKER: DDT came into general use the per-acre potato yields practically doubled. Numerous early reports indicate that the pioneer cabbage grower had to con- tend with about the same insects that plague the cabbage grower of today, but the pioneer had no arsenal of effective in- secticides. Lime, lye, and ash mixtures advocated by some growers were of little use except in those cases where the plants were so heavily coated with one of the mixtures that physical contact between the insect and the plant was practically impossible. The scalding water drench proposed by some persons was at times of value, but was very apt to damage the plants. ‘The arsenicals were used spar- ingly and on small plants only ; they could not be safely employed on more mature cabbages. “Thus, for many years the sound, unblemished head of cabbage was a rarity, and there was always danger of consuming protein with the slaw. In fact, it is very doubtful if any kraut made in those days could have passed present day Food and Drug Administration inspec- tions for insect fragments. There are those who contend that the prevalence of scurvy in the armies of the North and the South during the Civil War was in no small measure due to the fact that farm- ers could not produce adequate quantities of cabbage and related cole crops. Although some nicotine and pyrethrin products had been known for many years, they did not come into practical use until about 1910. Derris, cubé, and other ro- tenone preparations made their appear- ance in the 1920’s. When properly ap- plied, these insecticides were quite effec- tive, but they possessed very limited re- sidual properties and were relatively ex- pensive. ‘Their acceptance by cabbage growers was not enthusiastic, and ento- mologists were under constant pressure to improve formulations by the use of synergists or stabilizing agents. “Then came DDT and the organic phosphate in- secticides, and it looked for a time as if the cabbage growers’ insect problems were effectively solved. But the insects once again demonstrated their mutability, and soon cabbage worms were resistant to DDT. Today the entomologist is worse off than he was in the early 1940's, be- cause the cabbage growers, having once Economic ENTOMOLOGY 13 experienced the fine performance and economy of DDT in the early 1950’s, are unwilling to settle for anything less eff- cient. ‘The currently recommended spray schedule, which calls for using endrin un- til cabbage heads begin to form and fin- ishing with occasional applications of phosdrin or parathion, is a highly effec- tive treatment, but the growers remem- ber equally satisfactory results with the less complicated use of DDT. Sweet corn growers in Illinois, like the cabbage growers, must cope with an insect problem that requires both a thorough knowledge of the seasonal ac- tivities of the pest and a rather meticulous control treatment. The corn earworm is a native American pest that has long con- tested man’s right to the sweet corn pro- duced in Illinois. Unlike the cabbage worm, this insect has continued to defy man’s best efforts to control it. Several reasonably effective control measures have been developed, but none has been fully accepted by Illinois sweet corn growers. The corn earworm control measure cur- rently recommended involves precise but not unreasonable methods of application and accurate timing of treatments. Some Illinois sweet corn growers have been un- able or unwilling to apply the requisite control measures. When infestations of the corn earworm are light, mediocre con- trol practices prove adequate, but, when infestations are heavy, more meticulous practices are essential. In parts of Flor- ida and Texas, where sweet corn growers cannot afford to gamble on having light infestations, many growers produce 97 to 99 per cent clean ears of corn by care- fully following the control measures rec- ommended by entomologists. Cereal and Forage Crop Pests Insect, depredations were by no means confined to the fruit and vegetable crops produced by the early settlers in Illinois. Wheat, corn, and even the native prairie grasses were subject to attacks that at times amounted to almost total crop de- struction. In an article in the first issue of The American Entomologist, a writer, presumably Walsh, observed: Few persons are aware of the enormous amount of wealth annually abstracted from the pockets of the cultivators of the soil by those 114 insignificant little creatures, which in popular parlance are called “bugs,” but which the sci- entific world chooses to denominate “insects.” Scarcely a year elapses in which the wheat crop of several States of the Union is not more or less completely ruined by the Chinch-bug, the Hessian Fly, the Wheat Midge, or the Joint Worm. . . . The White Grub attacks indiscriminately the timothy in the meadows, the corn in the plowed field, the young fruit trees in the nursery, and the strawberry beds in the garden; always lurking insidiously under ground, and only making its _pres- ence known to the impoverished agriculturist _ by the losses which it has already inflicted upon him. at periodic intervals the Army-worm marches over their fields like a destroying pestilence; while in Kansas, Ne- braska, and Minnesota, and the more westerly parts of Missouri and Iowa, the Hateful Grasshopper, in particular seasons, swoops down with the western breeze in devouring swarms from the Rocky Mountains, and, like its close ally, the Locust of Scripture and of Modern Europe, devours every green thing from off the face of the earth (Walsh & Riley 1868a:1). Certainly Walsh was in a position to know the armyworm problem, because in 1861, 6 years before the creation of the State Entomologist’s Office, the Rock Island and Chicago and the Illinois Cen- tral railroads granted him, as a member of the Illinois Natural History Society, passes that permitted him to spend sev- eral weeks studying a major armyworm outbreak that developed in central and southern Illinois. That fall, in typical Walsh style, he wrote: . I always hate to give nothing for something, and having been obliged by the railroad companies, I endeavored, to the extent of my poor abilities, to return the obligation, by seeking a remedy for a little pest, that has this year destroyed one-fourth part of the tame hay grown within the limits of the State (Walsh 1861:350). This was the introduction to an ex- tremely interesting and informative 15- page report on the ecology of the army- worm and its natural enemies which he appended to an essay prepared for de- livery at the annual meeting of the IIli- nois Agricultural Society. Walsh re- ported: When they [armyworms] leave the meadows in which they originate, they travel on—some- times as far as half a mile—until they meet with wheat, rye, oats, corn, sorghum, or Hun- garian grass (Walsh 1861:351). Many instances are on record of the great difficulty with which they have been kept out Ittinors NarurAL History SurvEY BULLETIN Vol. 27, Art. 2 of houses which happened to lie in their path (Walsh 1861:352). From the Prairie Farmer of July 4, — the 1861, Walsh (1861:351) quoted words of ‘an accurate observer’ who described an infestation of armyworms: — “As to their number, they have been seen — moving from one field to another, THREE — TIERS DEEP. A ditch has been filled with — them to the depth of THREE INCHES IN HALF AN HOUR.” Walsh was fortunate in being able to acquire, through contacts with a number of pioneer settlers, valuable notes on his- toric armyworm outbreaks of the past. Some of these notes seem worthy of repe- — tition as an example of the fund of un- | published entomological history and knowledge that has passed from one gen- eration to another: As we might expect from the laws govern- ing the development of insect life, the army- worms make their appearance in noticeable numbers in different years in different parts of the State. I have no doubt that they exist in small numbers in every part of the State from year to year; for although they have never appeared till 1861 in the neighborhood of Rock Island, in such numbers as to attract attention, yet I myself captured a single specimen of the army-worm moth in Rock Island county, in each of three years, 758, ’59 and ’60. At Okaw they are recorded to have appeared in 1850; in the south part of Vermilion county, in 1835; and Mr. Joseph Bragshaw, of Perry county, says that they visited that county in ’25, ’26, 34 39% Jonesboro, in Union county, one of the oldest and most respected citizens of Southern IIli- nois, informed me that about 1818 or ’20 they were far more numerous there than in 1861, and that in 1861 there would not be a single cock of hay put up in his neighborhood save one meadow which was part clover and part timothy, and which I can myself testify was — ” badly “patchy,” there not being more than an eighth part of it which would turn out a good swarth of clover, the timothy being “nil” throughout. In 1838 again, according to the Colonel, there were but few of them. In 1842 they were about as in 1861; and in 1856 they occurred only in small numbers (Walsh 1861: 353). It certainly is an encouraging sign of the progress of entomological discovery in this State, that a noxious insect of primary impor- tance should have been, for the first time, traced through all its transformations in the year 1861 by no less than four citizens of IIli- nois to my certain knowledge—I refer to Mr. Cyrus Thomas of Murphysboro, Mr. Emery of the Prairie Farmer, Col. Dougherty of Jones- boro, and last and least myself (Walsh 1861: 356). ROLES IES TDR ae s ei - Eto oa ae Nh te te Matec 41 and ’42. Colonel Dougherty, of % December, 1958 DECKER: While many of the observations made by Walsh and the other gentlemen men- tioned were sound and are still valid, one observation was in error and resulted in a recommendation which, although it had the desired effect, was based upon a false premise. Walsh (1861:349) advised, “Burn your tame grass meadows over annually, in the dead of the year, and get your neighbors to do the same, and you will never more be troubled with the army worm.’ Walsh thought that the armyworm passes the winter in the egg stage, but such is not the case, and there- fore burning, as he recommended, did not destroy the eggs. We now know that when the moths appear in the early spring they fly at night; in the daytime, they hide in rank grass, preferably a dense mat of old, dead grass in a vigorous meadow. There, in April and May, they lay their eggs. Thus, while winter burning did not destroy eggs, it had a profound effect on the number of worms developing in burned-over fields and often, if not usu- ally, prevented serious infestations from developing. The recommendation for burning per- sisted for several years, and by 1880 it was supplemented by a recommendation for the use of dusty trench barriers to trap worms on the march. Spraying strips with Paris green was proposed by some, but was generally considered both dan- gerous and impractical. The use of poison bait (a mixture of bran and Paris green) for the control of armyworms, cutworms, and grasshoppers came into use about 1885, and with minor modifications remained the principal and most practical control measure available until the advent of the modern chlori- nated hydrocarbon insecticides. Since 1951, growers have been generally suc- cessful in controlling armyworms_ by spraying with such materials as toxaphene, dieldrin, and endrin. Furthermore, with the insect outlook and warning service bulletins available weekly during crop seasons from the Natural History Survey, Illinois farmers are now able to control -armyworms effectively when the worms are one-fourth to one-half grown. Ap- plied control measures save the small grain and the meadow grasses as well as protect adjacent crops from migrations. Economic ENTOMOLOGY Ls The chinch bug, another infamous pest, has been well known to Illinois farmers since 1820. This species, like the army- worm and many others, is not a serious pest every year, but tends to be sporadic, perhaps somewhat cyclic, in its appear- ance. Weather, of course, is a factor that influences the chinch bug population. One is indeed surprised to learn that the farmers of 1860 were just about as much aware of this pest as are the farm- ers of 1958. In 1861 Thomas (1865: 466-7) observed: Although we cannot predict with certainty one season the action of insect enemies for the next, yet we often can from the character of the season itself, know that certain species are likely to be upon us in increased numbers. This was the case the present season in re- gard to the appearance of the “Army-worm.” The cold, cloudy spring hanging so long before opening into summer weather, caused the ex- clamation from several of our older citizens, “T wouldn’t be surprised if we had the Army- worm this season.” Although this was rather guessing, yet there evidently pervaded the minds of the elder settlers a semi-conscious feeling of dread in regard to this insect, which most assuredly originated from the similarity in this spring to the previous seasons when it had appeared. And when the long dry weather we sometimes have in June and July has parched the vegetation, we may expect the grass-hoppers to multiply rapidly, and by their attacks on the plants already struggling for life, to soon effect a far greater injury than the same attack made on vigorous plants would have done. Later, Thomas (1880:242) observed, “The high temperature of 1854, ’71 and ’74, together with the diminished rainfall, furnish the key to the cause of the great development of the Chinch-bug during these years.” One could cite hundreds of quotations, from the Prairie Farmer and other early farm papers, concerning damage by the chinch bug and other field crop pests that would put the potato beetle reports to shame. But let the words of Walsh and of Thomas suffice. Walsh wrote as fol- lows: It is only two years since the entire wheat crop of the State was so damaged by the chinch bug that a great deal of it was not cut at all, and a great deal that was cut barely paid for the harvesting. Scarcely a year elapses but what more or less damage is done to it by this insect, and by the Hessian*fly and the wheat midge. A large breadth of winter wheat, which is commonly supposed to be “winter- | . q a 116 Ittinois NAarurAL History SurvEY BULLETIN Vol. 27, Art. 2% . ~ ¥ / = = mi Aes ea ee ee es Te. = A ae < ie Ie ee is ee co - cee iA oe Je ag i eas vB sr Ss aL ei. Jee pees a eal oe ae pe Teed 7 - ES ie iS | pea ieogerorses = rine Sd ae vi as L es |i 1S ee SSS — a > oe ‘ WA ps 1 AREA OF STUDY ABOUT 120.000 SQ. MI. OR 310800 SQ. KILOMETERS. A a DISTRIBUTION OF DENSE POPULATION OF CHINCH BUG, BLISSUS LEUCOPTERUS (SAY) mmm SERIOUS DAMAGE TO CROPS tsa SLIGHT DAMAGE @ 1 in ry Survey and its parent organizations make possible the study of population trends Maps of Illinois and parts of adjoining states on which are shown areas of serious damage, slight damage, and no damage by chinch bugs in 10 birds, and mammals. years, 1840-1940. Records kept by the Illinois Natural Histo such groups as insects, fishes, December, 1958 killed,” is in reality killed by the Hessian fly; and there may be, and probably are, many other insects which depredate upon this crop, but whose habits have not yet fallen under the notice of entomologists (Walsh 1861:335). Taking the average of years, we may safely assume that a fifth part of the wheat crop— or, which is the same thing, a quantity equal to one-fourth of what we actually do harvest —is destroyed by insects. Even at the low price, therefore, of 75 cents per bushel, we have over four and a half million dollars’ worth of wheat annually destroyed by “little vermin which it is not worth our while to notice.” But this is not all. Other crops are damaged by other insects, though not generally to so ruinous an extent; so that we cannot put the whole annual damage done by insects to the State of Illinois at less than TWENTY MILLION DOLLARS (Walsh 1861:336). And Thomas (1865:457) wrote: “So much has already been written in the pa- pers of this State concerning the Chinch- bug (Macropus leucopterus, Fitch,) that I shall pass it by in this paper without further notice.” Shelford & Flint (1943) made a thor- ough study of the history of the chinch bug in Illinois. The figure on page 116 is presented to illustrate the type of his- toric records that have been made and preserved by the Natural History Sur- vey. The data on which the figure is based cover the century beginning in 1840. Records for subsequent years have, of course, been kept. Similar data have been collected for several other important pests. In the 1860’s and ’70’s, many measures were proposed for control of the chinch bug: abandon wheat and barley or corn; burn fencerows and all wild grass areas to destroy hibernating bugs; plant border crops to retard migrations; fertilize crops to get dense stands unattractive to the in- sects; and construct barrier lines of lime, salt, and carbolic acid solutions. “The measure most widely used was the dusty furrow. Each year saw some new version of the furrow proposed, such as pouring tar oil, road oil, or creosote into the fur- row to form a barrier; covering the fur- row with straw and setting it afire to de- stroy the bugs; digging post-hole traps in the furrow and later spraying the trapped bugs with kerosene and burning them. There was no great change until the paper fence barrier, proposed in 1934, was widely adopted, but even this barrier Decker: Economic ENTOMOLOGY 117 was not without precedent; over 50 years earlier the use of tar-covered boards set on edge and placed end to end had been proposed. ‘The later control measures, like the early ones, were scheduled to be used around harvest time. About 1945, the paper fence barrier was practically re- placed by the dinitro dust barrier, and in another 10 years this was replaced by diel- drin, sprayed on strips of ground along the margins of small grain fields where these fields adjoined fields of corn or later maturing grain. The more aggressive fol- lowers of research progress were spray- ing entire fields of heavily infested wheat as soon as chinch bug eggs began to hatch so as to protect the wheat crop itself from serious damage and to eliminate the necessity of establishing a barrier of any type 2 or 3 weeks later. In the past century, progress has been made in controlling many other insect pests that attack cereal and forage crops. Among the most important of these pests are the grasshoppers, the cutworms, the white grubs, and the hessian fly. Instead of attempting to summarize in detail, we note here some of the general trends in this area of insect control. Before extensive agricultural develop- ment of the state, a large part of Illinois consisted of broad expanses of prairie grass, much of which was replaced by timothy and other tame grass or cereal crops planted by farmers. Insects prefer- ring these crops became notorious pests, but as the acreage of grasses was reduced as a result of increased legume produc- tion, certain insects began to decline in importance. "These included the white grubs, the billbugs, the armyworms, the sod webworms, and the corn root aphid. The burrowing webworm and the cut- worm Luperina stipata have all but dis- appeared; not a single specimen of either has been received by us for identification in the last 20 years. As the rail fence was replaced by the wire fence, and roadsides and ditch banks were graded or otherwise cleaned up, the amount of giant ragweed and elderberry available to insects was greatly reduced, so that the common stalk borer became less important and the old spindleworm was practically extermin- ated. Likewise, as the pot holes and low spots were drained, wireworm damage in 118 those areas declined steadily. Conversely, in certain dry, sandy areas which were brought under irrigation wireworm dam- age increased. As legume production increased, the in- sect pests of legumes tended to increase. Notable examples are the clover leaf wee- vil, clover root borer, pea aphid, bean leaf beetle, sweet clover weevil, green clover- worm, and spotted alfalfa aphid. Two attempts to initiate and promote the commercial production of sunflowers | in Illinois were doomed to failure largely because of the overwhelming insect prob- lems encountered when many species from the native sunflowers swarmed onto the cultivated varieties. In contrast, we find that in extreme southern Illinois cotton production survives in a rather unfavor- able climate, and under other adverse conditions, largely because important cot- ton insects are absent and planters are spared the cost of extensive insect control measures. Pests of Forest and Shade Trees and Ornamental Plants Effective control measures are now available for most of the insect pests of trees and ornamental plants; yet man seems to have little success in combating these insects. It is not that these insects are new or relatively unknown, for the majority of these pests were recognized and well known prior to 1850. The bark lice (scale insects), round-headed borers, flat-headed borers, bark beetles, bagworm, walnut caterpillars, cankerworms, and the 17-year locusts are frequently men- tioned in the Illinois entomological writ- ings of a century or more ago. Chemical control measures were not available at that time, but some of the proposed meas- ures were partially effective and more or less practical. Mechanical barriers and sticky bands were used to control the can- kerworms, sometimes successfully and sometimes not. It now appears that im- proper timing and failure to recognize the difference between the spring and the fall cankerworms accounted for most of the variation in control. Hand picking was often mentioned and, according to re- ports, if done diligently it was effective in controlling the bagworm, the walnut caterpillars, and the tent caterpillars. Ittrnois NatuRAL History SURVEY BULLETIN Vol. 27, Art. 2 Hand grubbing, with a wire or knife, was considered an effective means of control- ling several species of borers. types of soapy washes were proposed for the control of aphids and scale insects, but perhaps the most positive, wisest, and most ingenious of all recommendations was that proposed by Dr. Mygatt (1855: 516) in his essay on the bark louse: “Whether you choose a seedling or graft, by all means TRANSPLANT A CLEAN TREE, if you have to occupy hours and even days in examining and clearing your trees from every scale.” As insecticides and means of applying them were being developed for use on various agricultural crops, it was nat- ural that most of them would be tested to determine their potential usefulness in controlling insects attacking trees. The value of Paris green in controlling the cankerworms was established at a very early date. By 1910 lead arsenate, first developed in 1891 for use against the gypsy moth, was being recommended for a variety of leaf-eating insects, and by 1925 high-powered sprayers, dusters, and even airplanes had been developed and were quite generally available for use in treating both shade and forest trees. Nev- ertheless, progress was slow; apparently the weather and tree protection have something in common—everybody talks about them, but nobody does anything about them. The average citizen who professes an interest in and a love for trees is some- times like the kibitzer who, at an active poker table, talks a good game, but, for reasons best known to himself, fails to put his money on the line. In the past 2 years in many Illinois communities, beautiful landscape plantings, such as juniper, val- ued at hundreds of dollars were rendered unsightly and in many cases were killed outright by the bagworm; a dollar’s worth of malathion, or the old faithful, lead arsenate, and 30 minutes’ time could have prevented any damage. In some commu- nities there has been a wholesale loss of elm, oak, and birch trees of inestimable value and irreplaceable in less than 3 dec- ades; little evidence was available that control measures were even considered. This seeming indifference in some com- munities is partially offset by the genuine Several © December, 1958 DECKER: interest of a number of ardent tree lovers and conservationists in other communities. Some of these tree lovers, however, clamor for more research without mak- ing full use of the control measures al- ready available. Scientists have spent many years in developing fairly efficient and practical control measures for 90 per cent of the insect pests affecting shade trees and ornamental plants, yet we find that these measures either are ignored or are employed in less than 1 per cent of the cases in which they might be useful. It seems doubtful whether administrators will feel justified in diverting any con- siderable portion of their funds to similar projects until there is evidence that the control measures already recommended are being put to better use. A recently published circular (English 1958) will bring interested people up to date on con- trol of insects attacking ornamentals and shade plants. Insects Attacking Man and Animals Entomology has made its most pro- found and spectacular advances of the past 100 years in combating those insects that are pests to man and animals. There seem to be two good reasons why this is so. In the first place, we have learned consider- ably more of the habits and relative im- portance of these pests than was known in 1858, and, in the second place, as the medical implications of these pests became apparent, state and federal public health agencies, men in many branches of science, and the general public gave wholehearted support to large research and action pro- grams. Early Illinois entomologists had col- lected and identified many species of ticks, mites, mosquitoes, and flies, and it did not require the services of a scientist to advise farmers that large numbers of these species were sources of annoyance to their livestock, their families, and them- selves. A couple of very casual comments adequately attest to the ferociousness of these pests: ‘There are prairies in Cen- tral Illinois, as I am credibly informed by -numerous witnesses, across which it is im- possible to ride or drive a horse in the heat of a summer’s day on account of the Tabanus’” (Walsh quoted in Cresson et al. 1865:18). The genus Simulium in- Economic ENTOMOLOGY 119 cludes “the Buffalo-fly of Illinois and the West, which I have observed killing poul- try in great numbers, and which is known to torment horses and other animals to death, when very numerous” (Barnard 1880:191). While these reports may sound far- fetched and exaggerated, the latter is sup- ported by a more recent experience. In 10 days of April, 1945, black flies killed 125 head of horses and mules and untold numbers of poultry in Franklin and Wil- liamson counties, Illinois. Possible relationships between these insects and several of the most dreaded diseases known to occur in the state were unknown in 1858 and for the most part were unsuspected. For example, no one thought of connecting the common house fly with the spread of cholera that took the lives of one-tenth of the population of several western []linois communities in the 1830’s or with the outbreaks of ty- phoid fever and dysentery that were so common during and immediately after the Civil War. It seems ironic that B. D. Walsh, the first State Entomologist, was driven from his farm near Cambridge by a malaria epidemic and that he never suspected the mosquitoes that increased with the dam- ming of the river as being responsible for the epidemic. All we know of this inci- dent is contained in two sentences of Walsh’s obituary by C. V. Riley (1869- 70267): Finally, a colony of Swedes settled in his neighborhood, and, by damming up the water at Bishop Hill, produced so much miasma in the vicinity, that very much sickness prevailed there. His own health in time became im- paired, and at the suggestion of M. B. Os- born, of Rock Island, he removed to that city in 1851, and entered into the lumber business. Indeed, there is every reason to believe that neither Walsh nor any of his con- temporaries even suspected the relation- ship between mosquitoes and malaria. In his zeal to protect all beneficial insects and to maintain the balance of nature, Walsh was inclined to regard house flies, horse flies, and mosquitoes as_ possibly more beneficial than destructive. In 1865 he was quoted as saying: The scheme of the Creation is perfect and Na- ture is never at fault. It is only when Nature’s 120 system is but half understood, that we heed- lessly complain of its imperfections. We blame the house-flies for annoying us, and fail to see that in the larva state they have cleared away impurities around our dwellings, which might otherwise have bred cholera and typhus fever. We execrate the blood-thirsty mosquito, and forget that in the larva state she has purified the water, which would otherwise, by its ma- larial efHuvia, have generated agues and fevers. In all probability, when we rail at the Tabanus that torment our horses in the summer, we are railing at insects which, in the larva state, have added millions of dollars to the national wealth, by preying upon those most [insidious] and unmanageable of all the insect- foes of the farmer—subterraneous, root-feeding larvae (Walsh quoted in Cresson et al. 1865: 18). An editor of The Practical Entomolo- gist, in commenting on Walsh’s paper, cautioned his readers: Before you undertake to kill off the larvae of the Horse-flies and the Mosquitoes, you had best make yourself quite sure that they are really your enemies, and not, as Mr. Walsh maintains, some of your very best friends (Cresson et al. 1865:18). Flies and mosquitoes passed practically unmentioned until about 1880 when, be- cause of the insects’ annoyance and nui- sance characteristics, a few workers began to investigate suppressive measures. Win- dow screens and the use of smoke came into the picture first, followed by oil sprays, crude repellents, and several fly traps. If we exclude the modern insecti- cides developed since 1940, most of the control measures that are recommended today for the control of flies and mos- quitoes had been developed by 1900. By the combined use of drainage, good sani- tation practices, screening, and the known insecticides such as lime, borax, oils, ar- senicals, and pyrethrins, public health agencies made remarkable progress in re- ducing the incidence of insect-borne dis- eases, but it was not until DDT and the more recent synthetic organic insecticides became available that it was possible to reduce fly and mosquito numbers to the near vanishing point and to eradicate al- most all insect-borne diseases of man. Shortly before the outbreak of World War I, the country embarked on an all- out “Swat-the-Fly” campaign that car- ried over into the dairy industry. This campaign stimulated interest in the devel- opment of sprays for use on livestock, as Intinois NatrurAt History SurvEY BULLETIN Vol. 27, Art. 2 well as space sprays for use in and around buildings. Unfortunately, many of the formula- tions used prior to the late 1930’s were only partially effective flies, and in many cases the injury they inflicted on cows exceeded the benefits de- rived. It was difficult, if not impossible, to establish clearly the fact that flies did affect milk production and that good fly control would pay dividends in the form of higher milk production. In the last 10 years, with the new insecticides such as DDT, methoxychlor, and several ef- fective organo-phosphates, and with some repellents far more effective and much more persistent than anything available prior to 1940, it has been possible to dem- onstrate that good control of flies, whether they be tabanids, stable flies, or horn flies, will result in an increase of milk production of as much as 10 to 25 per cent. ‘The exact gains depend upon the intensity of the fly population, the species involved, and the duration of the attack. Significant findings in this field have been reported in a number of scien- tific articles (Bruce & Decker 1951, 1957, 1958; Bruce 1952, 1953). BIOLOGICAL CONTROL Man discovered at a very early date that not all insects are bad, that some are definitely his allies, some are indifferent or neutral, and some are in the category of Dr. Jekyll-Mr. Hyde—half good and half bad. Walsh, Le Baron, Thomas, and other early entomologists in their writ- k i ’ in controlling — ings repeatedly referred to the necessity — of distinguishing between man’s foes and friends in the insect world, and empha- sized, as did their successors, the import- ance and potentialities of parasites and predators in the natural control of insects. In December, 1854, William Le Baron, who 16 years later became the second State Entomologist of Illinois, wrote: Birds benefit the agriculturist by destroying countless myriads of noxious insects, whilst they injure him by consuming a part of those products which he would fain reserve for his own exclusive benefit. But it is the universal testimony of those who have investigated the matter, that the evil compared with the good which they accomplish is extremely trivial. Probably every reader of ornithology will call December, 1958 DECKER: to mind, in this connection, the computation of Mr. Wilson the ornithologist, the result of which was, that the single species of Red- winged Blackbird, which is usually considered one of the greatest pests of the farmer, con- sumes in one season, in the United States, six- teen thousand and two hundred million of noxious insects (Le Baron 1855:559-60). In an essay on insects, prepared in 1861 at the invitation of the Illinois Agricul- tural Society, Cyrus Thomas (1865:462, 464) made several pertinent comments on insect control measures, the balance of nature, and the biological control of in- sects: When we have obtained a complete knowl- edge of the laws of nature, and shall have at- tained to perfection in agricultural pursuits, then most assuredly our reliance for a check upon these insect enemies will be upon the parasites a kind Providence has provided for our benefit. And the reason for so doing will be that then we will work in accordance with the laws of nature which are adapted to our best method of living and acting. Then if this theory be true, the nearer we can approach such a condition, individually or collectively, the better it will be for us. Let the birds go unmolested, or even go so far as to entice them to abide near you. Learn to distinguish insect enemies from insect friends, and when you find the hiding places of the latter, as far as possible, protect them from injury. When you find a swarm of ‘“Lady- bugs” huddling around the root of a tree in the winter, throw a few dry leaves over them that the birds may not see them. When you see the eggs of the Syrphus fly lying singly among those of the Aphis, do not molest it, for the young larvae will surely destroy that nest. And when the bright banded flies hover like bees around you, during the hot days of sum- mer, while resting beneath the shade, brush them lightly away, and remember they are your friends. And when you see the eggs of the Lace-winged fly (Hemerobius) mounted on their long stalks on the leaves of your plants, let them alone, the voracious larvae they pro- duce will soon destroy the most numerous colony of plant lice. Benjamin Walsh (1861 :339-40, 341) likewise had something to say about the balance of nature and the value of para- sites and predators: Now it is universally the case, that when- ever man, by his artificial arrangements, vio- lates great natural laws, unless by some arti- ficial means he can restore the overturned bal- ance, he pays the penalty affixed to his offense. The voluptuary may overload his stomach, but, unless he has recourse to his dinner pill, he pays the penalty of an indigestion. So with the farmer and the horticulturist. Until they can Economic ENTOMOLOGY 121 restore the natural equilibrium which has been disarranged by their artificial processes, they pay the penalty in the damage inflicted on them by plant-feeding insects. They must as- sist nature, whenever, for necessary purposes, they have thwarted and controlled her, if they wish to appease her wrath. If these views be correct, it would seem to follow, as a necessary consequence, that one of the most effectual means of controlling noxious insects is to be found in the artificial propagation of such cannibal species as are naturally designed to prey on them. Although, so far as I am aware, cannibal insects have never yet been bred for utilitarian purposes, yet it is by no means an uncommon practice to collect such as are found at large in the woods and fields, and apply them to sub- due some particular insect that is annoying us. The foregoing quotations portray not only the profound interest in biological control that these early entomologists pos- sessed but also the breadth and depth of the general knowledge of the day. Forbes, who followed Thomas as State Entomologist, was likewise interested in parasites and predators. The fact is im- pressive that, in studying the biology and ecology of insect pests, these men invaria- bly made extensive notes on the parasites and predators encountered. While others before him had made notes of entomopha- gous fungi and other evidences of disease, Forbes was the first to examine the possi- bilities of control of insects by their dis- eases. In fact, he is regarded by many as the father of insect pathology in the United States. His work on the chinch bug fungus and the work by Dr. F. H. Snow of Kansas are outstanding classics of early research in this field. Forbes did not limit his interest and research in insect pathology to chinch bug diseases. He noted, and in many cases studied in great detail, the diseases found in numerous lepidopterous larvae, aphids, white grubs, grasshoppers, and_ several other insects. In the late 1880’s he was strongly advocating more thorough stud- ies on the possible advantageous uses of contagious insect diseases, and his Eighth Report (Nineteenth Illinois Report), published in 1895, contained a monograph of nearly 150 pages on chinch bug dis- eases. In general, the success of attempts to propagate insect diseases and to dis- seminate them as a means of controlling noxious insects in Illinois has not been as 122 spectacular as sponsors and interested ob- servers had hoped. These projects have been greatly underestimated by the pub- lic; control of insects by their diseases has a value that should not be ignored. If nothing more, these studies demon- strate the important role that insect dis- eases play in the natural control of many important pest species. They also shed light on the epizootiology of these dis- eases, which may prove to have even fur- ther value. Unfortunately, in practically all cases these projects were initiated on the premise that an epidemic would be initiated that could and would completely eliminate the pest species in a matter of days or weeks. When extermination of the offending pest was not immediately forthcoming, public sentiment turned from hope to disgust and ridicule, and re- searchers were forced to abandon their studies for lack of financial support. It is doubtful whether there is a single case in which an honest appraisal of the long- range or even the immediate value of dis- ease inoculation or dissemination, or a combination of both, has been made. In recent years we have belatedly come to realize that insect pathogens have not been adequately explored nor their poten- tial value determined. We and others are renewing our efforts in this basic field of research. The performance of a protozoan dis- ease of the European corn borer, a disease which, like the parasites of the hessian fly, apparently accompanied the host when it migrated to North America, seems worthy of mention. In Illinois the disease was first observed in the north central part of the state in 1945, 6 or 7 years after the borer made its first appearance in Kanka- kee County. The disease was artificially introduced into all sections of the state by colonizing disease-infected borers in many widely scattered counties. It is now prev- alent in all parts of the state and has for several years been an important, if not the most important, factor in holding corn borer populations to relatively low levels, where they can be successfully con- trolled by other means at a greatly re- duced cost. In a co-operative effort, the Illinois Natural History Survey, United States Department of Agriculture, and Illinois Ittinors NaturAL History SuRVEY BULLETIN Vol. 27, Art. 2 Conservation Department introduced a virus disease obtained from Canada to combat a serious outbreak of a pine saw- fly, Neodiprion sertifer, that in 1952 was raging out of control in the Henderson State Forest. The virus took hold in a spectacular fashion, and sawflies died by the thousands. Whether the virus can be — given full credit or not remains to be de- termined. In any case, the sawfly has not been reported as doing serious damage in that area since 1953. The value of parasites imported from abroad to help control accidentally intro- duced species has also been underesti- mated. Here, as in an effort to control an insect pest by disease, the public seems to expect the immediate annihilation of the pest species or it regards the effort as a complete failure. To demonstrate that — a species need not be annihilated to be prevented from causing appreciable dam- age, let us look at the record. The hes- sian fly and the wheat midge were both introduced in colonial days as immigrants from Europe. Fortunately, several of their European parasites came along with them in the same lots of straw, but, as usually happens, each pest reproduced and spread faster than its parasites. In due time the parasites overtook their hosts, and, for over a century, they have been important factors in preventing these pests from eliminating wheat production from the list of agricultural enterprises in Illinois. When the oriental fruit moth appeared in Illinois in 1927, the Illinois Natural History Survey, in co-operation with the United States Department of Agriculture, obtained, for release in Illinois, oriental fruit moth parasites (principally Macro- centrus ancylivorus) reared in New Jer- sey. These were colonized at several points in the infested southern [Illinois counties. At first the results of the ex- periment did not appear promising, but consistent recoveries were made in 1934, and eight surveys made since then have shown that parasitism by this species ranged from 17.3 to 53.2 per cent and averaged 36.5 per cent. While the para- site has not eliminated its host, it has held the population to a level where peaches can be adequately protected with a mini- mum use of insecticides. The average December, 1958 DECKER: percentage of the fruit infested since the establishment of the parasite is less than one-tenth what it was before colonization of the parasite was initiated. Shortly after the European corn borer made its appearance in the Midwest, at- tempts to introduce several of its parasites into the infested area (1926-1930) were relatively, if not wholly, unsuccessful. Later attempts, in which the I]linois Nat- ural History Survey and the United States Department of Agriculture co-op- erated (1944-1950), were more success- ful, and a Tachinid fly, Lydella stabulans grisescens, became firmly established in all sections of the state. Surveys made annually for the past 10 years have shown that, for the state as a whole, 15 to 40 per cent of the overwintering corn borers are parasitized and destroyed by this fly. In many instances parasitism in some of the northern Illinois counties has run as high as 80 to 85 per cent. While this parasitic fly has not eliminated the corn borer, it plays a very important role in holding this pest in check. VALUE OF INSECT CONTROL Man’s progress in applied entomology is partly obscured by the ever-changing circumstances and conditions of insect control. Quantitative data on the exact magnitude of insect damage are generally unavailable, and only the more or less catastrophic insect outbreaks are ade- quately recorded in the literature. ‘There are few specific points of reference with which we can compare the present with the past. Our memories are often faulty. We recall that Grandfather had a home orchard and how much we enjoyed the fruit; only after prolonged meditation do we also recall that only 1 apple in 10 was fit for storage in the fall, and that even in preparing a pie from the stored apples Grandmother had to cut out numerous areas damaged by codling moth. Despite the paucity of precise quanti- tative data, entomologists have developed practical control measures for a long list of once serious pests. Orchardists are now able to produce fruit crops 90 to 99 per cent free of insect damage instead of crops only 10 to 50 per cent free of in- sect damage, as they were 100 years ago Economic ENTOMOLOGY 123 or as they are now in abandoned or un- sprayed orchards. The Colorado potato beetle, which came close to eliminating Irish potato production just about 100 Table 1.—Number of acres treated with insecticides and estimated profit from treat- ment for a few important insect pests of cereal and forage crops in Illinois, 1953-1957. NUMBER OF NUMBEROF ESTIMATED YEAR PEsT SPECIES ACRES PRroFIT FROM CONSIDERED* ‘TREATED ‘TREATMENT 1953 10 770,625 $ 8,596,995 1954 7 1,095,165 7,130,258 1955 9 1,532,859 13,983,855 1956 10 1,405,624 7,097,630 1957 11 934,224 2,696,960 Average 9 1,147,699 § 7,901,140 *Insects considered in these surveys: spittlebug, leaf- hopper, spotted alfalfa aphid, sweet clover weevil, pea aphid, soil insects, chinch bug, cutworms, grasshoppers, European corn borer, and fall armyworm. years ago, is no longer regarded as a seri- ous pest. The grasshoppers, the army- worms, and the chinch bug, which less than a century ago caused many Midwest- ern pioneers to give up in despair and to abandon their farms, can now be con- trolled with comparative ease. The prin- cipal insect vectors of important human diseases have been brought under control to such a degree that the once dreaded diseases—malaria, typhoid fever, dysen- tery, cholera, and bubonic plague—are little more than an unhappy memory. Reasonably effective measures for the con- trol of important household pests such as the bedbug, cockroaches, stored-grain pests, clothes moths, and. carpet beetles have brought peace of mind to the house- wife and have contributed much to in- crease the comfort of the home. Measures developed for the control of insects at- tacking livestock—ticks, tabanids, stable flies, lice, and screwworms—have contrib- uted much to the livestock industry. The successes mentioned above were attained despite the drastic rise in level of accep- tance imposed by the public, the United States Food and Drug Administration, and market grades and standards. Under present regulations, the diseased and dam- aged condition of fruits, vegetables, grain, and other agricultural products that were accepted at the turn of the century would eliminate them from moving in interstate 124 commerce or even from being sold on the local market. Though it is not possible to establish monetary values for each of the accom- plishments just mentioned, the almost $8,000,000 average annual profit, table 1, resulting from the use of insecticides on cereal and forage crops in Illinois illus- trates the benefits of entomological re- search. There are those who will say that ag- riculture cannot afford the cost of insect control or that the farmer dare not add such charges to his overhead cost. Such assertions are economically unsound. The overhead charges associated with the planting, cultivating, and harvesting of each acre of crops are fixed. If a farmer can increase yields sufficiently to provide a cash return of two, four, eight, or more times the cost of insecticide treatment, the extra harvest is produced much more cheaply than the rest of the crop and thereby increases net profits and effects a reduction of operating costs. Insect control—or the lack thereof— may have an indirect bearing on economic and sociological considerations in addi- tion to those related to crop savings or crop losses. By increasing per-acre yields, maximum utilization of insect control measures might enable upwards of a mil- lion acres of Illinois farm land to be re- tired from cultivation and put to new uses. Some reactionaries will argue that increased yields would mean overproduc- tion and lower prices; this argument has been applied to almost every new techno- logical development. For years we have been attaining pro- duction goals by mining the soil—by wringing from it the fertility that must be replaced if future generations are to have their share. Economically and mor- ally, we are obligated to produce maxi- mum yields as efficiently as possible on a minimum number of acres. The surplus land should be removed from annual cul- tivation and its fertility maintained or improved with soil building practices em- ployed until such time as an expanding population requires further production. Even if Illinois could afford to squander its land resources and its manpower, the support of research for effective insect control would still be a foresighted invest- Ittrnors Natura History Survey BULLETIN Vol. 27, Art. 2 ment. When men of wisdom, interested in the nation’s future, combine forces in building a sound agricultural program, insect control will rank high in the list of technological musts. EMPHASIS FOR THE FUTURE Throughout the past century in IIli- nois, the extent and variety of insect con- trol problems, which were often of an emergency nature, dictated that entomol- — ogy be strictly applied and be aimed at immediate, practical goals. Perhaps the pressure for immediate, practical results reached its peak in the mid-1940’s, when a number of new and apparently highly effective insecticides became available for study and use. Everyone wanted to know at once what these insecticides were good for, how they should be used, and what hazards might be involved in their use. Now this pressure is subsiding; the IIli- — nois farmer is in possession of reasonably — practical control measures for most of his important insect pests. Economic en- tomology in Illinois is now in a position to seek information on the basic problems of insect control. This statement does not mean that all the insect problems of I]linois are solved ; we should not be surprised that new prob- lems will arise as new insect species are introduced and as species already here modify their habits or adjust their re- sponses and behavior to an ever-changing environment. However, we have appar- ently reached a turning point that will re- quire a revision of our responsibilities and will materially alter our objectives and — procedures. With reasonably effective control meth- ods available for most pests, and with the majority of our basic crops in surplus production, emphasis on the temporary solution of immediate problems and on increased production must logically be shifted to the development of more basic studies ultimately leading to new meth- ods of insect control. A review of the his- tory of chinch bug, armyworm, codling moth, and potato beetle control makes it — apparent that progress came in_ steps spaced 10 or 20 or more years apart. In entomology, as in other branches of sci- ence, real progress is made through the December, 1958 development of some new fact, some bio- logical or chemical law or principle re- ferred to as a “break-through,” discov- ered by scientists pursuing basic research. Practically all entomologists agree that Nature is more efficient than man in con- trolling insects; there is an urgent need for a return to the basic study of insect biology and ecology and for expanded work in the promising field of biological control. With a more thorough knowl- edge of the environmental factors that favor insect reproduction and_ survival and of those factors detrimental to these processes, man might conceivably control some pests by diminishing the favorable factors, enhancing the unfavorable fac- tors, or pursuing both courses. This type of basic research is expensive, and prog- ress comes slowly, but successful projects based on the accumulated results of such research pay handsome dividends. While more intensive studies in insect genetics, ecology, and biology may play increasingly important roles in the devel- opment of new insect control procedures, man will for many years find it necessary to rely on chemical weapons—insecticides —to fight many of his insect pests. As more and more toxic insecticides are de- veloped, it becomes increasingly important that they be thoroughly tested for safety before they are placed in general use. The evaluation of insecticide residues, their degradation products, and possible ad- verse effects on man and other animals, is currently time consuming and expen- sive. We must undertake considerable basic research to discover and to develop basic principles or natural laws that will simplify insecticide evaluation and reduce the cost of pursuing such routine studies. Come what may, man must never be- come complacent with his temporary suc- cesses nor assume that the insects have given up or will give up their struggle for supremacy. We must be ever mindful of the theses of L. O. Howard (1933) that insects are better equipped to occupy the earth than are humans; insects have been on earth for 40,000,000 years, while the _ human race is only 400,000 years old. As Forbes (1915:2) soberly asserted: The struggle between man and insects began long before the dawn of civilization, has con- tinued without cessation to the present time, Decker: Economic ENTOMOLOGY 125 and will continue, no doubt, as long as the hu- man race endures. It is due to the fact that both men and certain insect species constantly want the same things at the same time. Its intensity is owing to the vital importance to both of the things they struggle for, and its long continuance is due to the fact that the contestants are so equally matched. We com- monly think of ourselves as the lords and con- querors of nature, but insects had thoroughly mastered the world and taken full possession of it long before man began the attempt. They had, consequently, all the advantage of a pos- session of the field when the contest began, and they have disputed every step of our in- vasion of their original domain so persistently and so successfully that we can even yet scarcely flatter ourselves that we have gained any very important advantage over them. There seems to be little question that insects will continue to demand tribute of enormous proportions which will have to be paid in terms of damage, pain, and suffering caused by the insects, or in ex- penditures for insect control. Man may, through judicious expenditures for re- search and practical insect control meas- ures, reduce or minimize the tribute to be paid, but he can never eliminate it entire- ly. In this connection, it should again be noted that entomology is not static. In- sects, as highly versatile living organisms, are constantly changing to meet each change in the environment, whether it be biological, physical, or chemical. If we are to hold our own in this continuing battle, research must be carried on un- diminished, and, if we are to make prog- ress, research must be expanded. At the moment, entomology and re- lated biological sciences appear to be los- ing ground. State and federal appropria- tions have not kept pace with rising costs. Basic research is currently financed largely by grants from the principal en- dowed foundations. If it were not for funds made available by chemical and other large industrial companies, applied research in entomology would have been greatly handicapped and curtailed-in the last decade. Today, faced with the fact that an- other nation was the first to launch a man-made earth satellite, America is sub- jecting her own research facilities and educational system to critical review. At the moment, the physical sciences are in the limelight and apparently stand to profit from increased emphasis. That the 126 Intinois NATURAL History SurvEY BULLETIN natural sciences can safely be relegated to a secondary or back-seat position is open to question. Almost 100 years ago, B. D. Walsh, deploring American neglect of the natural sciences, observed: ‘“They manage these things better in Europe. In Russia and other continental states, En- tomology in its rudiments is made a por- tion of common school education” (Anon. 1860:12). There is every reason to believe that current entomological research in other countries is in no way inferior to our Vol. 27, Art. own. If the biological sciences, including entomology, are neglected in a revitalized educational program, America may find herself again out-distanced by other coun- tries—by men who are trained in a sci- ence-oriented system that is balanced to include all areas of scientific endeavor. If one step forward in the physical sciences causes us to slide two steps backward in the biological sciences, all our efforts spent to initiate a sound program for the ad- vancement of science—all science—will have proved useless. Faunistic Surveys N their beginnings and early develop- ment, investigations of the fauna of the Midwest differed in several respects from similar endeavors in other parts of the world. The Midwest was explored and collected intensively considerably later than the eastern American seaboard, so that the advances in the knowledge of the North American fauna made in the eastern United States were available as an aid to moderately rapid advances when faunal studies were begun in the Mid- west. In the eastern United States and also in Europe, systematic investigations were begun in response to man’s _in- herent curiosity concerning the kinds of life in his surroundings and were de- veloped to a considerable state of ad- vancement chiefly under this stimulus. In the Midwest, the first serious syste- matic efforts were undoubtedly begun in answer to pure curiosity, but almost im- mediately after their inception, especially in Illinois, these studies were picked up and swept along by the tremendous de- mand for identification caused by the agricultural and scientific developments of the latter half of the nineteenth century. EARLY BACKGROUND The sudden formation of natural his- tory societies in the Midwest during the 1850’s — at Louisville in 1851, Grand Rapids in 1854, Milwaukee in 1855, and Chicago in 1856—gives an impression in retrospect that before that decade there were no naturalists in the area. This was far from the case, for a few enthusiastic naturalists were active in various lo- calities through the Midwestern region even before these dates. Among the Midwestern naturalists were the famous zoologists Thomas Say, C. A. Le Sueur, and G. Troost, living and working on the banks of the Wabash River at New Harmony, Indiana, in the 1820’s and 1830's, and C. S. Rafinesque at Louisville, Kentucky, in the 1810's AEE RS ERT Ee ROSS and 1820’s. Many other persons collected material for these men or sent speci- mens for identification to taxonomists in the eastern United States or Europe. The early faunistic workers of the 1840’s and the 1850’s in Illinois included such men as Cyrus Thomas, John A. and Robert Kennicott, J. B. Turner, and Benjamin D. Walsh, all of them self- taught naturalists. These and other en- thusiasts made accurate observations on the fauna, built up collections of various animal groups, and kept in touch with their confreres in the eastern states. The Illinois entomologists published articles, some of them in the Prairie Farmer, and absorbed the ideas of such great early entomologists as IT. W. Harris of Mas- sachusetts and Asa Fitch of New York. In Illinois the State Agricultural So- ciety, formed in 1853, was an important agent in bringing together Illinois zo- ologists, entomologists, and botanists into an organized natural history society. The progressive officers of the Agricultural Society were conscious from the first of the destructive nature of insects and were sufficiently versed in biological concepts to realize that applied biology requires a full knowledge of all forms of natural life. To encourage acquisition of this knowl- edge, the Agricultural Society offered prizes at its state fairs for collections in natural history fields. In 1854 Wm. J. Shaw of Tazewell County won first prize for the “Best suite of the animal king- dom, including insects and animals in- jurious to the farmer” (J. A. Kennicott 1855:122). In 1855 Robert Kennicott won two prizes, one for the “Greatest and best collection of named insects,” the other for a zoological collection; in 1856 he won seven firsts—for a collection in each of the following classes: shells, named insects, zoology, botany, stuffed birds, rep- tiles, and fishes (J. A. Kennicott 1857 :90, 142). In the State Agricultural Society’s first Transactions, three lists of animals for Illinois were published, one on southern [ 127 ] 128 Illinois birds by Henry Pratten (1855), one on the Mollusca of southern I1linois by H. A. Ulffers (1855), and another (solicited by the Society’s secretary) on the animals of Cook County by Robert Kennicott (1855). It is interesting that in this last article Kennicott recorded “buffalo” and elk for Cook County and noted that the “wild pigeon’ (passenger pigeon) was “very abundant” and the magpie “not uncommon in winter.” For a few years after the first corpo- rate form of the Illinois Natural History Survey had come into being as the Illi- nois Natural History Society, the Agri- cultural Society published the proceed- ings of the infant organization. In Illinois the faunistic worker of 1858 had few of the work aids which we en- joy today. The only Midwestern institu- tional reference collection was that at Northwestern University, built up by Robert Kennicott and considered out- standing in its day, although small and limited in group representation compared with collections now available. Most zoologists accumulated their own private collections, identifying their speci- mens with the aid of the few books avail- able and through consultation with other naturalists. Few libraries existed in the area. The reference shelves of the best zoologists contained comprehensive treat- ments covering the eastern North Ameri- can fauna for most of the vertebrates and the Mollusca. For the insects Say’s vol- umes were available, but for many orders his treatment was fragmentary. For most insect groups and many other inverte- brates, extremely helpful world synopses had just been written by European au- thors, and some of them contained sepa- rate keys for the North American spe- cies. Aside from these basic references, there existed a number of journals carry- ing short papers, some of them published by the scientific societies of the Atlantic seaboard states, where such societies had been organized a century before their Midwestern counterparts. This period, the 1850’s, was a stirring one scientifically. Europe had just wit- nessed the successive development of com- parative anatomy and physiology, the cell theory, embryology, histology, and the theory of evolution. These basic concepts Intinors NArurAL History Survey BULLETIN did not immediately influence faunistic work in North America but they did so — later to a greater and greater degree. In North America prior to the 1850’s, the great bulk of the invertebrate material, including insects, had been sent to Euro- pean specialists for description. Follow- ing the pioneer examples of Frederick Vol. 27, Art. 2. Melsheimer and Thomas Say with in-— sects and mollusks, American zoologists — were beginning to describe more and_ more species of the native American — fauna. In the invertebrate groups they had virtually a virgin field, for in 1858 great numbers of species were still un- known, and workable synopses were avail- able for only a small proportion of the native American fauna. CHANGING HABITATS Originally Illinois was chiefly a com- bination of forested hilly country and flat mesic prairies of a marshy nature. Inter- spersed with these main types were sand areas, bogs, river and stream _ habitats, and other local areas of diverse kinds. The rapid rise in the population of Illi- nois in the mid-nineteenth century initi- ated in the native vegetation drastic changes which have progressed steadily to the present time; these changes have had a marked effect on the distribution and composition of the animal life of the state. By 1858, towns or farms or logged- over areas had broken up large tracts of forest. Plowing had made great inroads into the prairies. Large area drainage op- erations in the marsh country had started about 1850, had gained great momentum by 1880, and by 1900 had turned the great bulk of the marshland into farms. The resultant changing ecology is a back- ground feature important to keep in mind when viewing the faunistic developments outlined in this chapter. PERIODS OF FAUNISTIC ACTIVITIES The faunistic activities of the Illinois Natural History Survey and its prede- cessors may be divided into three fairly distinct periods, the initial, chiefly vol- untary, period of roughly 1858-1869, the - December, 1958 Ross: expansion period of roughly 1871-1922, and the specialized faunistic survey pe- riod of roughly 1923 to date. Initial Period, 1858-1869 The Illinois Natural History Society, when formed in 1858, had as its primary objectives the exploration of the biota of Illinois and the establishment of a scien- tific library. Encouragement of animal studies was patently aimed at systematics; yet even in the inaugural presidential ad- dress by J. B. Turner there is more than an overtone of putting systematics to work. In the words of Turner (1859: 647), A true philosophy, as it seems to me, would never let us rest content till we had truly and fully learned not the bare name and form, but the final cause and use, the good and evil, the full relation of each thing, object and being, to all other beings, and especially to man—to all his interests, enterprises, arts, uses and developments, physical, mental and moral. At the anniversary meeting in 1860 at Bloomington, certain objectives of the Society were expressed differently but in equally broad terms (Anon. 1860:3) : It is the aim of the Society . . . to establish a Museum of Natural History, at the State Normal University, comprising every species of plants, birds, shells, fishes, insects, quad- rupeds, minerals and fossils, found in Illinois, together with such collections from various parts of the world as will assist our youth in gaining a knowledge of the general studies of nature. The Natural History Society did in fact found a museum at Normal, Illinois, which served as a rallying point for zo- ologists of the area. The Society’s papers and proceedings continued to be published by the Agricultural Society, which fur- ther continued its active encouragement of faunistic work by awarding prizes for exhibited collections at the state fair. At about this time several []linois nat- uralists began publishing accounts of the zoology of the state. C. D. Wilber (18614) described a fossil mastodon, Thomas (1861a, 18614) wrote lists of mammals and of some insects, R. H. Holder (1861a, 1861) wrote about birds, and Walsh (1861-1868) published a re- markably fine series of papers before his FAUNISTIC SURVEYS 129 death in 1869. Although a skeleton net- work of railroads crisscrossed the state, most of the collecting was local, because it had to be done as a hobby appended to the naturalist’s business or other oc- cupation; hence, the papers were based chiefly on material from a few localities. Collections exhibited at the state fairs give another informative light on faunis- tic activities of that time. At the 1859 fair three entries were exhibited, one a red deer, another a collection of stuffed birds, and the third a collection of in- sects. In 1860 seven entries (Reynolds 1861:190-1) and in 1861 eight entries (Reynolds 1865:137) were exhibited in zoology. There were no more exhibits in zoology until 1864; in that year the winners were chiefly the Illinois Natural History Society and Illinois Wesleyan University at Bloomington (Reynolds 1865:310). Apparently these two groups enjoyed some rivalry at that time in the development of natural history. An idea of the high merit of these ex- hibits can be gained from the 1861 Awarding Committee’s remarks (Reyn- olds 1865:149) on the insect exhibits: In Entomology, a collection exhibited by T. G. Floyd, of Macomb, entitled the exhibitor to the “commendation” of the Society. In this department, Dr. Charles A. Helmuth, of Chi- cago, made a fine exhibition. His collection of Beetles is very valuable and attracted much attention. He has over 1100 species col- lected in Illinois, besides many fine species from other States and foreign countries. We think him entitled to “very high commenda- tion,’ especially for specimens exhibited be- longing to the order of Coleoptera. But by far the best collection exhibited was presented by B. D. Walsh, Esq., of Rock Island. It is hardly possible to speak in too high terms of this extensive collection of the insects of Illinois. So far as Illinois insects are concerned, it outnumbers in the order of Coleoptera, the collection of Dr. Helmuth, and is very full in all the other orders. It could only have been collected and arranged by an exercise of industry, [perseverance] and skill, and by an application of scientific knowledge, reflecting great honor upon the collector and entitling him to high rank among the Naturalists of the State and of the country. The Committee do not hesitate to pronounce his the “best collection illustrating the Entomology of Illi- nois,’ and unanimously award to him the premium of the Society. In spite of the achievements in faunis- tic activities shown by both publications 130 ILtrnors NarurAL History SuRVEY BULLETIN and exhibits, the Natural History So- ciety itself faltered because it could not make ends meet on private subscriptions alone and by the end of the 1860’s was a mere shell of an organization. Expansion Period, 1871-1922 The establishment of the State En- tomologist’s Office in 1867 and the in- corporation of the Illinois Natural His- tory Society into the State Board of Ed- ucation in 1871 brought together as off- cial state organizations two agencies in- vestigating natural science and marked the beginning of continuing state support for faunistic programs. The appointment of Walsh as first State Entomologist had little effect on this movement because Walsh confined his official writings almost entirely to nontaxonomic subjects. His successor, William Le Baron, introduced serious taxonomic contributions into the reports of the State Entomologist in 1871. In his first report as State Entomolo- gist, Le Baron described a new species of moth attacking apple, in his second described four more new species of in- sects of economic importance, and in his third gave an outline of and key to the orders of Illinois insects (Le Baron 1871: 20-3; 1872:117-24, 138-9, 140, 157-8; 1873:25). Here he called particular attention to the great need for identifica- tion aids in the pursuit of economic en- tomology. Le Baron’s was the first of much faunistic work which continued as an integral part of the development of economic entomology in Illinois. At al- most the same time (1871), the educa- tors and scientists of the state, alarmed at the continued decline of their Natural History Society, induced the legislature to take over and assign the Society’s mu- seum and library to the State Board of Education in exchange for state appropria- tions (Illinois General Assembly 1872: 151-2) for the Society’s continued growth. Thus, the need for state aid in the de- velopment of faunistics arose from two different directions. Both Le Baron and Thomas as State Entomologists published many fine taxo- nomic insect studies in their reports. Un- der the auspices of the Illinois Museum of Natural History, naturalists in the state Vol. 27, Art. 2 — published faunistic papers on a wide range — of Illinois groups, including Crustacea, fish, birds, reptiles, and insects. j The period 1858-1878 witnessed the — first concerted awakening of American naturalists to the taxonomic opportunities in the invertebrates, especially in the in- — sects. Specialists in many states published ~ comprehensive treatises on orders or fam- — ilies of insects of North America. these animals, this was truly the age of — North American discovery. In 1877 the Museum of the Natural — History Society, by that time known as the Illinois Museum of Natural History, — was separated into two institutions: the Natural History Museum, designed as — a public exhibition museum, in Spring- field, and the State Laboratory of Nat- ural History, at Normal (Illinois Gen- eral Assembly 1877:14-6). The duties — of the State Laboratory, presumably as — set forth by Stephen A. Forbes, its Di- — rector, stressed ecological approaches to — the animal life of the state and in this — policy reflected thoughts expressed by Turner 20 years before. The primary in- — tent of the systematic program described — was “to monograph those groups which — have not been thoroughly studied else-— where” (Forbes 1882a:9). In 1882 Forbes became State Entomol- ogist, as well as Director of the State Laboratory. Following the establish- ment of both of these offices at Urbana in 1885, the faunistic program received great impetus. Reading between the lines of the original reports of the Director, it seems safe to surmise that by this time the ecological studies already attempted had highlighted the pressing need for the accurate identification of the animal spe- cies encountered in these studies. In the revised list of duties of the State Labora- tory we find the directive, “he [the Di- rector] shall present for publication, from time to time, a series of systematic reports covering the entire field of the zoology . . . of Illinois” (Illinois Gen- eral Assembly 1885:23). In its Bulletin, the Laboratory had previously published many papers by nonstaff members, but from this time on a larger and larger pro- portion of these papers was the product of staff members of the State Laboratory or of the State Entomologist’s Office. For — December, 1958 Ross: The main faunistic activities of these staff members concerned aquatic organisms and insects associated with the develop- ment of ecology and economic entomol- ogy. Forbes repeatedly mentions that the most important tools of the biologist are 2 2 2 2 £ z : i FAUNISTIC SURVEYS 131 roads traversed the state and these were the only means of rapid travel. Collecting was done intensively around a few head- quarters, especially Urbana, Carbondale, and Havana. On the Illinois River and other waterways, boats were available Field party of the Illinois State Laboratory of Natural History at one of several collecting stations near Havana, 1894. This station was on the east shore of Thompson’s Lake, which has since been drained. In the picture are, left to right, Frank Smith and Henry E. Summers, zoolo- gists, Charles A. Hart, entomologist, and Miles Newberry, fisherman and boatman. a reference collection for the identifica- tion of specimens and a scientific library. All staff members collected specimens as part of their duties, and every effort was made to obtain material from different parts of the state and from areas of in- terest in adjacent states. By 1894 the collections were of sufficient magnitude to be placed under the charge of a cura- tor, C. A. Hart. In 1903 Hart became Systematic Entomologist and Curator of the insect collections, and R. E. Richard- son was brought in to take charge of the fish collections. In 1915 J. R. Malloch Was appointed to assist Hart with the insects. Collecting conditions from 1870 to well into the 1900’s were greatly dif- ferent from those of today. A few rail- for travel up and down the rivers. Local travel was done by horse-drawn vehicles. As late as 1900 Forbes (1901:3, 5-6) wrote of the Laboratory: Its field operations have been conducted mainly from the Illinois Biological Station [at Ha- vana and Meredosia] as a center,... Besides this local work on the fishes of the State, two extensive wagon trips have been provided for, one made in the fall of 1899, and the other in progress at this date [Sep- tember, 1900].... A considerable number of collections have also been made by high school principals and science teachers and sent to the Laboratory in aid of this survey. Hart and his assistants traveled to various points by train and in each town set up headquarters in a local hotel or rooming house, hired a buggy, and made 132 Intinois NaruraL Hisrory Survey BULLETIN day trips into the surrounding territory. In this way, over the years a remarkably fine collection of insects was built up from almost every part of the state. The establishment of the field laboratory at Havana formed a basis for many seasons of intensive insect collecting in the rich waters of that area and on the extremely interesting sand areas which line the east bank of the Illinois River through sev- eral counties. At the present time such restrictions on movement might seem a terrible handi- cap, but one must remember that in those days the land was not so intensively culti- vated as it is at present. Within a very short distance of almost any town, tracts of virgin forest, prairie, marsh, or other undisturbed habitats could be reached with little effort. Many of the old virgin landscapes which were the type localities of Illinois species are now either flooded by artificial lakes, under cultivation, or covered by urban developments. Most of the marshes, which were once common- place, have been drained. Because of the abundance and accessibility of varied habitats, the early collections were both large and diversified. The very nature of the substation headquarters method en- couraged the collection of all species of insects in a given locality, rather than specialization on any one group. Human labor was relatively cheap; hence, pre- parators and collectors could be_ hired and trained at a nominal cost. As a result, the State Laboratory in- sect collections (which constituted also the insect collections servicing the State Entomologist’s Office) became the finest which had ever been assembled for any one state, and early in the twentieth century the collections of fishes and cer- tain other groups were equally fine. This faunistic program reached a peak about 1910 and continued into the next decade. In 1917, when the State Entomol- ogist’s Office and the State Laboratory were combined to form the present IIli- nois State Natural History Survey, the reorganization did not effect any changes in the internal structure of the faunistic staff. Immediately afterward, however, the faunistic program began to dwindle. Many of the well-trained personnel ac- cepted positions in universities and other Vol. 27, Art. 2 scientific centers which were growing rapidly. World War I drew away much of the younger help. Richardson concen- trated on ecology. Hart, the work horse of the entomological collections, died in 1918, and in 1919 C. P. Alexander was appointed Systematic Entomologist. Al- exander and Malloch worked chiefly on stream surveys. The studies of Alexander resulted in a report on the Vermilion River (Alexander 1925). After the resignations of Malloch, in 1921, and Al- exander, in 1922, there were no faunistic taxonomists left on the Natural History Survey staff. No comprehensive faunistic projects had been in operation for several years, and these resignations left the Survey without even curators. Specialization Period, 1923 to Present The appointment of Theodore H. Fri- son as Systematic Entomologist in 1923 marked the beginning of a resurgence in the faunistic activities of the Natural History Survey. Until several years later this move was felt primarily in the in- sects, but eventually it spread to the other animal groups. Frison’s first endeavors were to collate the insect collections, but his chief thoughts were aimed at meth- ods for revitalizing the old charge to publish a series of systematic reports covering the entire field of the zoology of Illinois (Illinois General Assembly 1885:23). Forbes was as anxious as Frison to see this program begin. By this time several factors had changed the faunistic outlook considerably from that of the beginning of the century. Good roads reached almost every hamlet in the state, and the automobile had supplanted the train and buggy as a ready means of travel. The ease of reaching all points of the state made up in large measure for the increasing destruction of large tracts of native habitats and the necessity of seeking primeval collecting spots in re- mote and widely separated localities. Taxonomically the picture had changed to an equal extent, at least for insects. In 1900 it was generally considered that except in groups like aphids and ecto- parasites, species could be readily identi- fied by external characters through use of, at most, a hand lens. Variation had December, 1958 Ross: been little recognized as a factor in and a difficulty of identification. A reference series of a few specimens was considered thoroughly adequate for each species. Al- though the value of series of specimens was becoming recognized at the beginning of the twentieth century, the true neces- sity for larger population samples was not fully recognized in insect groups un- til about the 1920’s. By this time, in group after group of insects and indeed of other invertebrates, many of the older species units were each being divided into several species separated only by micro- scopic characters, which were often minute in character and difficult to see. So detailed was the knowledge required to identify many of these groups that it was no longer possible for one person to cover reliably the tremendous number of groups which Hart had done so success- fully according to the standards of his day. Influenced by these changes, a faunistic program was evolved centering around in- tensive studies of individual groups. The program called for each staff member to study some special group, collect material throughout the state at different seasons and in different habitats, identify the ma- terial, and write up a report of the group for Illinois. It was hoped that the serv- ices of specialists at other institutions could be obtained during the summer months to work with Natural History Survey personnel on Illinois reports. In the original plan, the thought was that these reports could be restricted quite closely to Illinois material and to Illinois species. This plan did in fact prove satisfactory for the aphids and Orthop- tera, which were relatively well known for the country as a whole. When, how- ever, projects were started for groups which were poorly known for the conti- nent, it was found essential to extend the scope of the reports to cover roughly the mid-central states, as Forbes had implied as a general policy as early as 1900. It was recognized early in this pro- gram that many insect groups of little importance economically were neverthe- less of great importance ecologically. An attempt was therefore made to develop a program which would alternate the treatment of groups having principally FAUNISTIC SURVEYS 133 economic importance with those having principally ecological importance. Within the bounds of a_ primarily systematic treatment, it was hoped that basic information could be obtained on the place of the species in nature. Collect- ing programs therefore stressed discover- ing the microhabitats, hosts, seasonal ap- pearance, or other ecological attributes of the different species. An aim of great importance which de- veloped for these reports concerned their usability from the viewpoint of the be- ginning student. Many keys made by specialists contained language too tech- nical to be readily understood by non- specialists. Frison was acutely aware of this fact and insisted that all keys in the faunistic bulletins be couched in language as simple as possible and that, wherever helpful to an understanding of characters or specialized terms, illustrations should accompany the keys. Frison’s plan for faunistic reports was not put into operation until 1928, when F. C. Hottes was employed during the summer as a special appointee to work on the aphids of Illinois. The appointment of Hottes was the first of several of its kind. In 1931, when Frison became Chief, Herbert H. Ross became Systematic En- tomologist. In 1935 the insect systematic program became the Insect Survey Sec- tion of the Natural History Survey. The identification of economic insects, always a duty of the Systematic Entomol- ogist, became an important feature of the Section. The Section was called on also for the identification of certain other invertebrates important in agriculture or public health, especially mites, _ ticks, aquatic Crustacea, and earthworms. In these activities, changing taxonomic con- cepts and the introduction of economic insects and mites new to the state con- tinually increased the difficulties of ac- curate identification and the need for ob- taining additional specialists for the staff. In 1947 the faunistic program was expanded to cover all animal groups, with the idea of extending to groups other than the insects the faunal survey aims which had been developed for insects. The Insect Survey Section was renamed the Section of Faunistic Surveys and In- sect Identification, and it became the 134 custodian of all the Survey’s taxonomic collections of animal groups. Over the years several artists have contributed greatly to the utility and ap- pearance of the Survey’s faunistic publi- cations—Lydia M. Hart, H. K. Knab, C. O. Mohr, Kathryn M. Sommerman, and Elizabeth Maxwell. Miss Hart and Dr. Mohr, especially, have graced Nat- ural History Survey publications with a multitude of remarkably fine total views of insects. RESEARCH COLLECTIONS The great value of research and refer- ence collections to programs in natural history was stressed in the founding ar- ticles of the Illinois Natural History So- ciety and has been evident ever since in all phases of applied ecology. The Natural History Survey has therefore stressed the assembling and maintenance of adequate research collections of animal groups as a corollary to its faunistic activities. The general aims in augmenting the collections have varied over the years, but in recent decades have approached closely the policy expressed at the 1860 anniversary meeting of the Natural His- tory Society and have emphasized first the species found in Illinois and then species or additional material from other regions which contribute to analyzing or interpreting the Illinois fauna. Taxonomists in other institutions have aided the Illinois Natural History Survey greatly by identifying Survev material in their respective specialties. This aid has not only resulted in keeping the Survey collection up-to-date but has afforded needed reference material in many genera or families. Vertebrates During the early periods of Survey history, Forbes and his assistants built up and maintained a large collection of IIli- nois fishes, but kept only a small reference collection of other groups. Much of the fish collection is intact at present, but the older material of other vertebrate groups has become dissipated. In recent decades emphasis has been placed on build- ing up collections of amphibians and Inuinois NATURAL History Survey BULLETIN Vol. 27, Art. 2 reptiles, especially variational series from Illinois and surrounding states; on start- ing reference collections of birds and mammals; and, more recently, on as- sembling fish collections designed to be a basis for a re-study of Illinois fishes. Invertebrates Other Than Insects In early records of the Survey, there is no indication of the extent of invertebrate collections other than that given by inci- dental mention in a few small published papers. The largest of these collections comprised the molluscs; the aquatic spe- cies were obtained chiefly from river sur- veys and the extensive series of land spe- cies from the collecting of Frank C. Baker and Thural Dale Foster. Early collections of other groups were made, at least of phalangids, crustaceans, and cer- tain protozoans, but only scattered vials or slides of these materials are extant at the present. Since 1930, special Illinois collecting has been initiated for a few groups, and in the pseudoscorpions and ticks excellent Illinois series have been assembled. Insects From the late 1870’s to the present, the insect collections grew steadily. The first official collection was Walsh’s pri- vate collection purchased by the State for Le Baron in 1870. Le Baron picked out duplicates for a reference collection in his office and then sent the main Walsh col- lection to the Chicago Academy of Sciences for safekeeping. There it was destroyed in the Chicago fire of 1871. Ironically, some of the material Le Baron selected from the Walsh collection may have persisted and be represented in the present Natural History Survey collec- tion. Since the extant Le Baron specimens lack locality data, however, it is impos- sible to determine their original source. A collection of aphids made by Thomas was preserved, also. The insect collection which Forbes be- gan in the State Laboratory was quite small while he was at Normal. As soon as he became established in Urbana in 1885, he started to place great emphasis on building it up. About 5 years later Forbes (1890:3) gave the following ac- count of the collection: | December, 1958 Ross: The entomological collection has been great- ly enlarged, especially in Diptera, and a large number of determinations in all orders have been made. The named collection is now con- tained in 160 double boxes, and numbers about 5,000 species, each being represented, as a rule, by four selected specimens. The pinned and determined duplicate insects on hand—largely in process of distribution to public schools—amount to 42,600 specimens. The alcoholic insects, including large numbers of larvae, are contained in about 10,200 bot- tles and vials. Although we have no later estimates of the size of this insect collection, it is obvious from material now in the collec- tion that by 1910 Hart was keeping much larger series of each species. In addition to material gathered by the staff, in the Natural History Survey col- lection are several collections of note that have been given to or acquired by the Survey. Notable items include the W. A. Nason collection (insects of Algon- quin, Illinois), the C. W. Stromberg collection (insects of northwestern [lli- nois), the Andreas Bolter collection (all orders of insects), the Emil Beer Lepidop- tera collection, the Charles Robertson collection (insects on flowers), the L. J. Milne caddisfly collection, the C. L. Metcalf flower fly collection, the W. P. Hayes weevil collection, the A. D. Mac- Gillivray sawfly collection, the P. N. Musgrave water beetle collection, and the K. F. Auden beetle collection. Amateur entomologists, such as Murray O. Glenn of Henry and Alex K. Wyatt of Chicago, have made numerous valuable additions to the collection. Because of special taxonomic interests on the part of staff members, the collec- tion is unusually comprehensive in certain groups of insects. To this category be- long the stoneflies, mayflies, and caddis- flies; the aphids, mirids, and leafhoppers; the leaf beetles, rove beetles, and June beetles; the sawflies and bees; the thrips and psocids; the springtails; and a few groups of the true flies. In many orders the collection contains a great deal of ma- terial of the immature stages, which have been emphasized in our reports. The large collections of rove beetles, sawflies, and ectoparasitic groups are associated with plans for future projects. Since 1925 primary types at the Nat- ural History Survey have been segregated FAUNISTIC SURVEYS 135 for reference and protection. In 1927 these represented about 1,000 species; the number now stands at about 2,500 spe- cies. At present the total insect collection contains roughly 2,000,000 specimens, in- cluding over 50,000 slide mounts, repre- senting about 40,000 species and housed in 2,700 insect drawers and 100,000 vials. FAUNISTIC REPORTS The preparation and publication of re- ports on the animals of Illinois, a respon- sibility repeated several times in mandates to the Natural History Survey and its predecessors, was begun with the first publications of the Illinois Natural His- tory Society and has been continued to the present. Many of the first reports were mere lists, often local in nature, and have needed revision or complete retreatment. In addition to the chiefly systematic accounts outlined below, ecological and economic studies over the years have con- tained a wealth of records and descrip- tions of a large number of species. This is true especially of surveys of the sand areas, prairie and forest areas, and exten- sive bottom fauna and shore studies of the large rivers. Vertebrates Faunistic reports have been published on all the vertebrate groups occurring in Illinois. Certain of the older reports are now out-of-date because of our greatly increased knowledge of the fauna. Fishes.—The work on Illinois fishes may truly be considered the first sustained faunistic project carried on by personnel of the Natural History Survey or its par- ent organizations. The project was begun with Forbes’ first connection with the Illinois Natural History Society and con- tinued as a cohesive systematic study until 1909. At the time of birth of the Illinois Nat- ural History Society, approximately three- quarters of the I]linois fishes had been de- scribed and named by such distinguished early ichthyologists as Rafinesque, Le Sueur, Girard, Agassiz, Mitchell, and Kirtland. Half a dozen of these species were first discovered in Illinois waters. During the next three or four decades, 136 when Illinois waters were being studied intensively by Forbes and his colleagues, most of the remaining Illinois fishes were described by such famous zoologists as Jordan, Cope, Gilbert, Nelson, and Forbes himself. A regional list treating the fishes of the Chicago area was prepared by Robert Kennicott (1855), and comprehensive catalogs of the fishes of the entire state appeared in the first volume of the Bulle- tin (Nelson 1876; Jordan 1878). Sev- eral years later Forbes (1884) prepared a third catalog of Illinois fishes, and early in the present century Thomas Large (1903) published a fourth list. Some time in the 1870’s Forbes seems to have developed the idea of producing a well-illustrated and detailed account of the Illinois fishes which would be useful for all the Mississippi River states. Year after year, wagon parties were sent to ex- plore and collect in different streams of the state until finally records were avail- able for virtually every river and rill in Illinois. Along the Illinois River large collections were made year after year. Some extensive collecting parties visited localities in neighboring states. The amount of human endeavor that went into this project is monumental and rep- resents the steadfast patience and toil of 30 years. The final report, The Fishes of Illinois and its Atlas, by Forbes & Rich- ardson (1908), summarized all this in- formation and featured a remarkable set of color plates prepared by Lydia Hart. Since the appearance of the Forbes & Richardson report, two other contribu- tions have been made by the Natural His- tory Survey to Illinois fish taxonomy. D. H. Thompson & F. D. Hunt (1930) published a report on the fishes of Cham- paign County, and D. J. O’Donnell (1935) published an annotated list of Illinois fishes. Birds.—Before 1858 there was an abundance of illustrative and synoptic references to North American birds by Wilson, Nuttall, Audubon, and others, and there were local lists of Illinois birds by Robert Kennicott (1855) and H. Pratten (1855). Later, R. H. Holder (1861a) published a list of Illinois birds and a short taxidermy manual in the Transactions of the Illinois Natural His- Intinois NarurAt History Survey BULLETIN Vol. 27, Art. 2 tory Society. In 1881 Robert Ridgway published a revised catalog and, a few years later, two large reports, the two volumes of The Ornithology of Illinois (Ridgway 1881, 1889, 1895). The first volume was destroyed by fire in the state printer’s office and had to be completely reprinted before it was issued. These two volumes were among the pioneers in the use of structural characters in keying the birds of an area. Ridgway, a native of Illinois, was not an employee of the state but wrote these volumes because of his intense interest in Illinois birds. In later years Forbes, A. O. Gross, and Frank Smith made many observations on Illinois birds, but these studies were pri- marily of an ecological nature. Amphibians and Reptiles.—Survey studies concerned with these animals did not start until the 1880's. In the first vol- ume of the Bulletin, N. S. Davis, Jr., & F. L. Rice (1883) published a catalog of amphibians and reptiles found east of the Mississippi River. H. Garman (1890) also studied these groups. No synoptic collections were kept of the early ma- terial. In the 1930’s Francis Lueth and Willard Stanley accumulated records and assembled several hundred specimens. In the early 1940’s the Natural History Sur- vey focused attention on these groups through the co-operation of H. K. Gloyd of the Chicago Academy of Sciences, C. H. Pope of the Chicago Natural History Museum, and H. M. Smith of the Uni- versity of Illinois. In 1947 P. W. Smith initiated an intensive study of these ani- mals, making collections in all parts of the state and plotting the variation and distribution of each species. In 1957 this project culminated in a comprehensive report on the amphibians and reptiles of Illinois; the report is now awaiting pub- lication. Mammals.—The Natural History Survey and its parent agencies have pub- lished only a small number of reports on Illinois mammals. The first, by Cyrus Thomas (1861), was published by the Natural History Society. Early in the present century, F. E. Wood (1910a) published on the mammals of Champaign County. In the 1930’s C. O. Mohr be- came interested in the mammal fauna of Illinois and gathered a great deal of in- a \ 5 December, 1958 Ross: formation on distribution and _ habits. After Mohr left the Natural History Sur- vey in 1947, the work on mammals was taken up by D. F. Hoffmeister of the Uni- versity of Illinois, and the resulting field- book appeared shortly after Mohr had rejoined the Survey staff (Hoffmeister & Mohr 1957). Invertebrates Other Than Insects Most of the invertebrate studies made during the early history of the Survey concerned chiefly aquatic organisms which were important in limnological inves- tigations. ‘The first paper by Forbes (1876) in the Bulletin was a list of the Illinois Crustacea; this was followed by a paper on Crustacea by L. M. Under- wood (1886). A. Hempel (1896, 1899) described a few rotifers and protozoans from the Illinois River, and C. A. Kofoid (1898, 1899) described a few plankton organisms of Illinois. R. W. Sharpe (1897), F. W. Schacht (1897, 1898), and Ernest Forbes (1897) made addi- tional contributions to a knowledge of the Crustacea. C. M. Weed (1890) did con- siderable work on the phalangids of I[lli- nois and published a partial catalog of the group. Several other invertebrate studies pub- lished in the Bulletin were almost en- tirely the work of nonstaff members, some of whom worked actively in co-operation with the Survey. J. P. Moore (1901) treated the Illinois leeches; Frank Smith (1895-1928) published many papers on earthworms; H. J. Van Cleave (1919) studied Illinois River Acanthocephala; Henry E. Ewing (1909) studied the orobatid mites; and F. C. Baker (1906) published a catalog of the Illinois Mol- lusca. Ecological work on the rivers amassed collections of the various plankton groups, but only those portions noted above were ever analyzed taxonomically. Much of the material was discarded after being recorded, and much was lost by desicca- tion. Except for the collections of Mol- lusca, by 1947 only a small amount of the early invertebrate collections — re- - mained. About 1930 a survey of the land snails of Illinois was organized under the lead- ership of F. C. Baker. The field work FAUNISTIC SURVEYS 137 was done primarily by T. D. Foster. Foster used a motorcycle on collecting trips and shared with S. C. Chandler the distinction of being one of the few mem- bers of the Survey’s motorcycle brigade. For 2 years he conducted a whirlwind search over the entire state for land snails and brought together a remarkable num- ber of records. The material was iden- tified by Baker, who prepared a report that appeared as a fieldbook of the Illinois land snails (Baker 1939). The book was beautifully illustrated by C. O. Mohr. Berlese collecting, instituted about 1933 primarily for exploring the insects in duff, netted not only insects but large numbers of terrestrial invertebrates, mainly arach- noids. About 1940 C. C. Hoff of the University of New Mexico became inter- ested in co-operating in a study of pseudo- scorpions of Illinois. He found that many species collected in these Berlese samples were new and represented a Midwestern faunal element which had remained un- seen because other pseudoscorpion §spe- cialists lived in either the East or the West. Hoff’s report on the Illinois fauna was published by the Natural History Survey (Hoff 1949). Insects Considering not only the economic im- portance of insects but also the exceed- ingly large number of species expected in the state (approximately 20,000), it is not surprising that the Natural History Survey’s most extensive faunistic contri- butions have been made in this group. Many of the studies have resulted in de- scriptions of new species, life history notes, and distribution records contained in short papers; many others have resulted in comprehensive accounts of various groups found in [Ilinois. Orthoptera.—Thomas was early a keen student of the Orthoptera and in the first of the T'ransactions of the Natural History Society published a list of this or- der for Illinois (Thomas 18594). His in- terest continued and he published a second, enlarged list in the first volume of the Bulletin (Thomas 1876). In the early 1900’s, Hart and A. G. Vestal made large and extremely interesting collections of this order in the Illinois sand areas, in which an appreciable number of western 138 I_ttinois NATURAL History SuRVEY BULLETIN species occur. In 1932 Morgan Hebard of the Academy of Natural Sciences of Philadelphia offered to prepare an account of the Dermaptera and Orthoptera of Illinois. For this project staff members made additional collections in areas of the state not previously covered for the group. The report appeared 2 years later (Heb- ard 1934). Aphids.—This group was one of the first emphasized in studies by the Natural History Survey’s parent organizations. Thomas, one of the leading early investi- gators in the taxonomy of this group, pub- lished a synopsis of one of the tribes and described many new forms from Illinois (Thomas 1878). About the same time Nettie Middleton (1878) described an- other species, and several years later C. M. Weed (1891) published the results of his studies on the life histories of a number of species. Little more was done with this group until J. J. Davis started Vol. 27, Art. 2 further taxonomic investigation of the aphids about 1908. In the Bulletin, Davis (1913) published a commentary on the Cyrus Thomas collection and in addition 20 papers on aphid taxonomy in various entomological journals. Most of this work he did while an assistant in the State Entomologist’s Office. In 1928 Frison and F. C. Hottes, the latter now at Grand Junction, Colorado, took up a study of Illinois aphids. This was the first study to be based on a com- bination of intensive collecting for one group and opportunities for rapid travel to all parts of the state. Field investi- gations were made during the summers of 1928-1930. Each year collecting parties started in the southern part of Illinois and worked north and then reversed the pat- tern so that each locality was collected at different seasons. A complete set of slide mounting equipment was taken into the field, and temporary headquarters were An Illinois Natural History Survey entomologist making field notes relating to insects he has collected. The association of insects with their host plants is an important phase of the work of Survey entomologists. December, 1958 Ross: set up in hotels at various towns. Each party consisted of three persons. Usually all three collected during the first half- day spent in each locality; after that one person stayed in the headquarters hotel and mounted aphids while the other two continued collecting. Lists of potential hosts, with especially interesting ones in- dicated, were used as a tick sheet in each locality. About a hundred species, 36 of them new to science, were added to the state list. The report on this project was published in the Bulletin (Hottes & Fri- son 1931). Odonata.—Nymphs of this order were frequently encountered in limnological work, and H. Garman and Hart reared many of them during the 1880’s and 1890’s. This work set the stage for the first report on Illinois dragonflies, an ar- ticle by J. G. Needham & Hart (1903). Later Philip Garman did much work on the group and wrote an excellent account of the damselfly suborder Zygoptera in Illinois (P. Garman 1917). Pentatomoidea.— This group includes the stink bugs, a group of sucking insects for which Hart had a special interest. He assembled a remarkably fine collection of the Illinois species and had virtually com- pleted an account of the state fauna at the time of his death. ‘The manuscript was completed by J. R. Malloch and was pub- lished in the Bulletin (Hart 1919). This report was especially useful because it in- cluded not only keys to the Illinois spe- cies but also keys to the Nearctic genera. Diptera.—The first serious work on the flies done for the Natural History Survey or a parent organization was by J. R. Malloch. Although interested in Diptera in general, Malloch specialized in the Chironomidae or midges, of great importance in the economy of Illinois waters. He reared a large number of these insects and was one of the first workers to delve into the minute char- acters of the male genitalia and the larval mouthparts as an aid in species discrimina- tion and identification. His rearings were done chiefly in the vicinity of Havana and Urbana, with a great deal of help from Hart, who also collected adult ma- terial from various parts of Illinois and surrounding states. The report by Mal- loch (1915) on the midges was outstand- FAUNISTIC SURVEYS 139 ing among faunistic works. Not only did it give equal emphasis to the adults and larvae, a most unusual feature for the time, but it benefited from two remark- able faculties of Malloch’s. One was Malloch’s ability to spot new characters (dipterists agree that Malloch was a genius at this not only in the midges but in every group in which he worked). The other was his ability to prepare un- usually clear keys, which made his publi- cations quite out of the ordinary in their usefulness to other workers. The breadth of Malloch’s interest in Diptera was expressed when he published in the Bulletin a classification of the order based primarily on larval and pupal characters (Malloch 1917). This study was one of the first in which recognition was given to the value of characters of the immature stages in determining the relationships of families within a large in- sect order. Certainly it is a classic and contains cogent ideas of fly classification which even at this date have not been fully incorporated into accepted classi- fications of the order. The next intensive Natural History Survey work on Diptera was a study com- menced by H. H. Ross about 1938 on the Illinois mosquitoes. Because of restric- tions on travel and lack of availability of personnel during World War II, field work and rearing progressed at a rela- tively slow rate. The report on these in- sects was published in the Bulletin (Ross 1947). Plecoptera.—Although the Plecop- tera or stoneflies are an abundant com- ponent of many aquatic communities, no state-wide taxonomic work on the Illinois species was done until Frison became in- terested in them in 1927. Previously Walsh (1863, 1864a) had observed and recorded many of the species occurring in the vicinity of Rock Island. Frison and another entomologist, R. D. Glasgow, loved to hike and picnic, especially in the hilly country along the Salt Fork River south of Oakwood, Illinois. On fall ex- cursions to this locality they noticed that, in some of the very small streams, the smallest of the stonefly nymphs kept in- creasing in size as winter approached. This observation excited Frison’s curios- ity and from it arose an abiding interest 140 Ittinois NaruraAL History SurRvEY BULLETIN in and love of stoneflies which continued through the rest of his life. Frison fol- lowed the development of these little stoneflies, which proved to be the small group called winter stoneflies. He discov- ered that little was known concerning the fauna of the Midwest and began a study of the group for Illinois. The first report on stoneflies treated a few small families comprising the winter stoneflies (Frison 1929). The collecting and rearing of species of the other families in the order were begun. Rearing these insects proved to be difficult because the laboratory water available at Urbana did not sustain the stoneflies. Copper cages on a raft placed in a stream were eventually devised to overcome this difficulty, but the losses of these expensive cages by vandalism finally proved so great that the practice was dis- continued. A considerable number of species were reared from emerging nymphs caught at the water’s edge. By one means or another, all the Illinois spe- cies were finally reared. Six years after publication of the winter stonefly report, a report covering all the Illinois Plecop- tera appeared (Frison 1935). Frison found sets of nymphal charac- ters which appeared to have great prom- ise for indicating natural groupings of the species and genera, indications such as Malloch had previously found when exploring characters of the larvae and pupae of Diptera. The studies of stone- fly nymphs set the stage for what might be called the modern classification of the order and stimulated emphasis on the study of immature stages in subsequent Survey projects on several other orders of insects. These insects proved so fascinating that Frison’s studies did not long stop at the boundaries of Illinois. Through material obtained on vacation trips and at other opportunities, the stonefly collection was enlarged to cover all of North America. With large series available from diverse areas of the continent, it became apparent that many of the old species were in real- ity species complexes, and as a result many of the Illinois populations had to be described as new. The results of these latter developments in the stoneflies were published in the Bulletin (Frison 1937, Vol. 27, Art. 2 1942a) and as shorter papers in various entomological journals. Megaloptera.—These, the alderflies and dobsonflies, were collected during the aquatic work on stoneflies and caddis- flies; some specimens were received from fishermen who had encountered them along streams and had sent them in for identification. Attempts to identify these Megaloptera by means of then current literature proved unsatisfactory. In the alderfly genus Sialis, characters noticed in the male genitalia seemed to provide an excellent means for positive determina- tion of the species and an analysis of these characters led to a re-evaluation of the species in the genus, many of which proved to be new. About half a dozen species were found in the material from Illinois and surrounding states. As part of an effort to learn something of the en- tire distribution pattern of the Illinois species, the study was extended to cover the fauna of the whole continent. The report on this study was published in the Natural History Survey Bulletin (Ross 1937). Miridae.—As the aphid project was coming to a close, H. H. Knight of lowa State College agreed to work summers with the Illinois Natural History Survey and prepare a report on the Miridae or plant bugs of Illinois. Knight was on the Survey payroll for three summers. Pre- viously Hart had assembled and identified an excellent collection of this group for the state, but since Hart’s time Knight had shown that characters of the genitalia indicated a much larger fauna than ear- lier workers had suspected on the basis of the external characters they used. The mirid field trip pattern followed that of the aphids, with the trips around the state scattered through the different — seasons. Again host collecting was em- phasized, and field headquarters were set up locally in hotels. The general plan was to collect until about 3 o’clock in the afternoon, and then pin up the day’s catch. With the Miliridae, this was thought desirable because of the fragile nature of certain diagnostic characters, especially pubescence, which might be brushed off if the specimens were relaxed and pinned later. Many thousands of specimens were collected each year, and December, 1958 Ross: again a large number of species, including about 20 new ones, were added to the state list. Members of the staff served as “ouinea pigs” to try out the keys, to point out spots difficult for the uninitiated, and to suggest improvements. Mohr did his usual excellent job in providing many total views of various species. “The report resulting from this project was published in the Bulletin (Knight 1941). Ephemeroptera.—The mayflies were early recognized as being one of the most important components of the fresh-water biota of Illinois, but, except for early local studies by Walsh (1863, 18640), lit- tle was done concerning their systematics in this state until about 1925. At that time collections were sent to J. W. Mc- Dunnough at Ottawa, Canada, who iden- tified a considerable amount of material. Collecting and rearing of species in the order were only sporadic until about 1937, when B. D. Burks, assigned to the project, began an intensive field program. Certain genera of the mayflies proved dificult to rear because the subimagoes seldom survived in cages, and in some species the nymphs did not molt to the subimaginal stage in still water. For these genera Burks worked out a neat con- trivance. He placed fully mature nymphs (which emerge at night) in a pan of water containing a large stone, placed the pan on the floor of a car at nightfall, and had the car driven over a gravel road. The wave action produced in the pan by the rough ride broke the surface film enough so that the nymphs could emerge. As the driver guided the car along the road, Burks sat in the back seat and periodically examined the pan with a flashlight; he captured each subimago as it emerged, put it in a vial for emergence to imago, and associated the cast skin with it. The extremely short period of adult emergence of many species frequently necessitated camping out along a stream and keeping an around-the-clock vigil for emergence. During one summer a rear- ing station was established at a_ fish hatchery along Nippersink Creek, in the -extreme northeastern part of the state, which is especially rich in mayfly species. A flash flood inundated the rearing rooms and nearly swept away the sum- mer’s material. ‘The material was _res- FAUNISTIC SURVEYS 141 cued as the vials were beginning to float out of the window in the shoulder-deep water. At first, Burks had difficulty obtain- ing good series of imagoes, although the subimagoes could be collected in quan- tity at lights. Burks found that he could catch great quantities of these sub- imagoes in paper bags, turn them loose in his hotel room, and have them emerge in fine shape, so that any desired number of imagoes could be secured. When Burks left the Natural History Survey in 1949, he had completed the mayfly report, which was published in the Bulletin (Burks 1953). Cicadellidae.—About 70 years ago, C. W. Woodworth (1887) published a short treatment of this family, com- prising the leafhoppers, and later Hart and Malloch made extensive collections of these insects, some of which were identified and recorded by W. L. Mce- Atee of the United States Biological Survey (McAtee 1924, 1926). Malloch himself (1921) wrote a short paper on the group. In 1934 D. M. DeLong of Ohio State University agreed to tackle the job of working up a more extensive treatment of the leafhoppers of Illinois. A few years prior to 1934, DeLong had begun an investigation of the male genitalia in the leafhoppers and found that, as in a number of other groups, many of the species previously identified on the basis of external characters were in reality clusters of species which could be separated primarily on the basis of genitalic structures. Both in North America and elsewhere the discovery of these characters had set off a tremendous burst of activity by leafhopper workers to explore these structures. It was in the midst of this burst of effort that the Illinois project was launched. DeLong and other staff members spent almost all of the next three summers crisscrossing Illinois and collecting leafhoppers in the various habitats of the state. During rainy weeks and also during the winter back in Columbus, Ohio, DeLong iden- tified these collections and continued his revisional studies. Various members of the staff made special collections as in- dicated by new taxonomic discoveries. 142 By 1945 it was apparent that a re- port embracing all the leafhoppers un- der one cover was impractical, and De- Long prepared the manuscript for about half of the fauna, which included all the subfamilies except the Cicadellinae. This report was published in the Bulletin (DeLong 1948). At this time, R. H. Beamer of the University of Kansas had drawn atten- tion to the tremendous number of Muid- western species contained in the genus Erythroneura, the largest genus of the untreated subfamily Cicadellinae. Mrs. D. J. Knull had identified a large part of the Natural History Survey material in this genus. Most of the several hun- dred species were known only from hi- bernation collections, and it was felt that, before proceeding with the manu- script on this subfamily, the host rela- tionships and other ecological informa- tion should be ascertained for these species. As a result the project was re- aligned and a new host-collecting pro- gram for the entire subfamily was dele- gated to the faunistic staff of the Survey. The large number of host associations al- ready established have proved of interest in contributing ideas concerning evolu- tionary problems in insects having moder- ately rigid host associations. Trichoptera.—A study of the caddis- flies was prompted by the importance of this group in the economy of IIlinois fresh- water habitats. The project was planned originally as a joint one with Dean Cor- nelius Betten of Cornell University, who had in manuscript at the time the first comprehensive and useful New World faunistic study of the group; his study dealt with the fauna of New York. Bet- ten in America and A. B. Martinov in Russia had pioneered in the technique of clearing the male genitalia of Trichoptera in KOH in order to get a more exact knowledge of these diagnostic structures. Betten spent 6 weeks on the II]linois Nat- ural History Survey staff in the summer of 1931, his time being spent partly on collecting trips around the state and partly in identifying the caddisfly ma- terial in the Survey collection. In 1932 press of other duties caused Dean Betten to retire from the project, which was then assigned to Ross. Ituinois NATuRAL History SuRVEY BULLETIN Vol. 27, Art. 2 Much of the caddisfly collecting was done as an adjunct to stonefly, mayfly, mirid, and leafhopper collecting, but spe-_ cial trips were made to springs and cer tain rivers, such as the Kankakee, which — supported unusual species. As the taxo-— nomic analysis of the material progressed, it became evident that the Illinois fauna differed in remarkable fashion from that of the only other state for which it was well known, New York. As a result, — it was necessary to practically revise the entire North American fauna before the 7 Illinois groups could be satisfactorily segregated to species. This was true espe-_ cially in the family Hydropsychidae and the so-called microcaddisflies, the Hydrop- — tilidae. As with the other aquatic groups, — an effort was made to rear the species and — associate larvae and pupae. Some of this — work was done with rearing cages, but the greater part was accomplished by as- sociating mature pupae with their corre- sponding larval parts in the cocoon or case. The report of the Illinois fauna of this order, including keys to the adults and immature stages, was published by the Natural History Survey (Ross 1944). — After this report appeared, some ac- tivity relating to the Trichoptera was continued, primarily centered around at- tempts to reconstruct the origin of groups and the dispersal patterns which led to the formation of the present Illinois fauna. As genera and families from other parts of the world were studied, it was possible to get a better understanding of the classification and evolution of the or-— der. It is reminiscent of Malloch’s and Frison’s work in the Diptera and Ple- coptera that the immature stages were found to hold the principal key to deduc- ing the evolution of the group. ‘These studies made possible the publication of the book Evolution and Classification of the Mountain Caddisflies (Ross 1956). Coleoptera. — The beetles have fre- quently been the subject of intensive study by the Natural History Survey staff. Early in the history of the organization, extensive rearing was done, and volumes — of important information on this work are scattered through the State Entomolo- gist’s reports. The first extensive Illinois publication on the order was by Le Baron (1874) who, in his fourth report as p Kaila nt ete te pl tet till eS a a. ee ———- December, 1958 Ross: State Entomologist, published an outline of the Coleoptera of Illinois, with keys to genera and notes on many species. The next serious study of the order concerned the genus Phyllophaga, the June beetles. The larvae of these beetles were extremely serious pests, and before 1890 Forbes and his assistants set about making systematic collections of the genus throughout the state. Forbes (1891) pub- lished a survey of the Illinois June beetles ; the publication included keys to the spe- cies written by Hart. R. D. Glasgow (1916) reviewed this material and pub- lished a synopsis of the synonymy and the description of a new species. Shortly after, J. J. Davis made a detailed study of the ecology of Phyllophaga and also became interested in their taxonomy. The study resulted in one fine paper on the natural enemies of June beetles and in another describing new forms. These two papers appeared in the Bulletin (Davis 1919, 1920). Glasgow continued his in- terest in the genus, but subsequently pub- lished only one or two small papers on the subject. In 1944 another beetle project was in- augurated, this one on the leaf-feeding beetles, or Chrysomelidae, with M. W. Sanderson as the investigator. The be- ginning of the leaf beetle investigation was based on a need for supplying cor- rect names for various species of economic importance to Illinois crops. Early at- tempts at identification disclosed that much of the older literature on the fam- ily was unreliable, and diagnosis of spe- cies often was uncertain. Not only were there deficiencies in the literature; few attempts had been made in North Ameri- ca to relate larval and adult morphology for generic or species diagnosis. “The proj- ect for Illinois was organized along the lines of earlier faunistic studies. Collec- tions were made throughout the state, with special emphasis on securing host- adult-larval associations. At present a report embracing two-thirds of the sub- families and including about a half of the Illinois species is nearing completion, and _a large proportion of the field work for other subfamilies is in an advanced stage. Thysanoptera. — Survey activity re- lating to this order of little insects, the thrips, had its beginning about 50 years FAUNISTIC SURVEYS 143 ago; J. D. Hood (1908) published a paper describing a group of species from Illinois. Late in the 1930’s, when Berlese sampling was started in the Survey, inter- est in this group was again aroused be- cause of the large number of specimens and variety of species which appeared in the collections from moss and leaf mold. In 1947 L. J. Stannard planned a com- prehensive faunistic study of the order for Illinois. Many difficulties were encoun- tered, including the inaccessibility of critical types, difficulties in finding satis- factory mounting media, and difficulties in interpreting existing keys and descrip- tions. The genera were especially poorly defined and inconsistently used, and be- fore satisfactory names could be estab- lished for the Illinois species it was neces- sary to embark on major studies in the general classification of the group. The results of one of these studies, investigat- ing the generic categories in the suborder ‘Tubulifera, were published by the Uni- versity of Illinois (Stannard 1957). As a consequence of all these factors the IIli- nois study of this group has come close to a treatment of the thrips for half the continent. Intensive collecting in all con- ceivable situations and at different sea- sons has brought to light large numbers of new state records. A report on these insects for Illinois is in an advanced state of preparation. Lepidoptera.—As mentioned earlier, in his first report Le Baron (1871) de- scribed a new species of moth. Since that time a great deal has been written, espe- cially in the State Entomologist’s reports, on the moths of Illinois. Most of this material, however, is in the form of small contributions on the descriptions of spe- cies, their larvae, or their habits. How- ever, Thomas (1881), with the assistance of Nettie Middleton and John Marten, published a synopsis of lepidopterous larvae for Illinois. This report included a similar synopsis by D. W. Coquillett (1881). Later, Forbes and his assistants prepared keys to certain economic spe- cies, and W. P. Flint & Malloch (1920) published in the Natural History Survey Bulletin a paper on the European corn borer and related species. In 1955 R. B. Selander began a fau- nistic project designed to cover many of 144 Ituinoris NatrurAL History SurvEY BULLETIN the families of small moths or micro- lepidoptera, which were poorly known in Illinois. The Blastobasidae were chosen as the first family for study because the genitalic structures of the Nearctic spe- cies had never been investigated. Selander, now with the University of Illinois, as- sembled large quantities of Illinois mate- rial and unearthed a diagnostic set of characters in the genitalia. Work on this project is continuing. Hymenoptera.—Aside from rearing and describing a few parasites and saw- flies, the Natural History Survey staff has done only one serious piece of work on the Illinois Hymenoptera fauna. This was a study by Malloch (1918) on the genus Tiphia. Collembola.—Although among the most abundant insects numerically, the Collembola or springtails were not stressed until 1928, when large collections were made in various parts of the state and sent to J. W. Folsom, U. S. Depart- ment of Agriculture, for identification. When Folsom died, the project reverted to simply a collecting program. Subse- quently, Berlese sampling added large quantities of these insects to our series. The project was revitalized when H. B. Mills joined the Natural History Survey in 1947; since that time steady progress has been made on a study of this group for I[]linois. RETROSPECT AND PROSPECT In following the objectives set forth in the original organization of the Illinois Natural History Survey, the faunistic program performs three principal func- tions pertaining to the animals of I]linois —assembling and maintaining research and reference collections, preparing re- Vol. 27, Art. 2 ports on the various animal groups, and identifying economic species. At times the — program has emphasized one function — more than another, but over the years — steady progress has been made in all three — departments. . Today the taxonomic methods by — which these functions are achieved are far more complex and_ time-consuming — than they were when the program was — started. If transplanted to today, the fau- nistic worker of 1858 would doubtless be astonished at changes in the species con- — cept, in taxonomic techniques, in micro- scopic and other equipment, and at the great increase in recognized invertebrate — species and genera. As these complications have developed, — it has become clear that there is no easy — short cut in making an adequate survey of an animal group for Illinois. Each re- — port represents a great deal of collecting and study over a period of years. Members of other sections of the Nat- ural History Survey have aided the fau- nistic program immeasurably by rearing — and collecting material, identifying host — or indicator plants, editing reports, and — assisting with library problems. Taxono- mists in other institutions have been of — great aid not only by publishing papers — of inestimable use in studies of Illinois species, but also by assisting in many other ways with specific problems. It is a tribute to the founding fathers of the Illinois Natural History Society that certain of their general principles were and still are remarkably good guides for a faunistic program. The importance ~ of combining systematics and ecology and of having a broad geographic scope for reference collections becomes more ap- — parent as new discoveries help unravel the complex faunal relationships of Illinois — species. Applied Botany and Plant Pathology HEN the Illinois Natural History Society was organized in 1858 to promote the advancement of science in the state, botany was a major field of interest of several of its founders. The earliest reported botanical research in Illinois was the study of flora in south- ern Illinois by André Michaux (Sargent 1889), a distinguished botanist of France. In 1795 Michaux traveled from the Ohio River up the Wabash River to Vincennes, Indiana. He crossed I]linois to Kaskaskia, August 23-30, to Prairie du Rocher, Sep- tember 5—6, and returned to Kaskaskia, September 8-9. On October 2, he started toward the Ohio River and arrived at Fort Massac on October 8. Later he re- turned to Kaskaskia, Fort Chartres, and Prairie du Rocher and started on his re- turn from southern [llinois on December 14. Following Michaux and during the first half of the nineteenth century, many physicians and amateur botanists studied and reported on the flora of Illinois. Dr. Lewis C. Beck (1826a, 1826), 1828), in publishing his contributions to the bot- any of both Illinois and Missouri, listed 65 plants in the prairies near St. Louis and 14 in barrens. Also, he reported on his studies of plants along the [Illinois River bluffs near St. Louis. A catalog of plants collected in Illinois by Charles A. Geyer was published with critical remarks by Dr. George Engelmann (1843) of St. Louis, Missouri. Dr. C. W. Short (1845) of Louisville, Kentucky, reported on his observations and collections of the flora of prairies of Illinois as a result of his extensive travels in several sections of the state. Dr. S. B. Mead (1846) prepared a catalog of plants growing in Illinois, most of them growing near Augusta in Hancock County; this work was _ pub- lished in the Prairie Farmer. Dr. Mead ‘mentioned the habitats of the plants he included in his catalog. Also, he listed the uses of the plants, including those used by dyers and coopers, those used for hedges, chair bottoms, hay, ornamentals, Te. DRC CAR rR edible fruits, common tea, and medicine, those known to be poisonous, and those known to be troublesome weeds. The year before the Illinois Natural History So- ciety was founded, I. A. Lapham (1857a) published a catalog of the plants of Ili- nois; his catalog included lists con- tributed by Mead and Engelmann. In pre- paring the catalog, Lapham examined the extensive collections of plants made by Robert Kennicott, Emile Claussen, and others. Mead’s list, as mentioned above, com- prised plants principally in the vicinity of Augusta in Hancock County. Engel- mann’s list comprised plants in southern Illinois, especially in the vicinity across the Mississippi River from St. Louis, Mis- souri. Dr. Mead, Lapham (1857a:494) wrote, “has probably devoted more time and labor to the examination of Illinois plants than any other botanist, and _ his collections now form part of most of the principal herbaria of the world.” Lapham emphasized that catalogs of plants were useful to farmers, physicians, horticulturists, botanists, cabinet makers, wheelwrights, and other workers in wood because these catalogs listed plants of in- terest to each group; his catalog listed 1,104 species representing 111 orders of plants. From a geographical point of view, Lapham divided Illinois into three districts: (1) the heavily timbered tracts, mainly in the southern portion of the state, and the “groves” or detached bodies of timber surrounded by prairies, in the middle and northern portions of the state ; (2) the open prairie tracts of 1 to 20 miles in diameter and destitute of trees; (3) the tracts of “barrens,” intermediate between the prairie tracts and the tim- bered tracts. The barrens appeared to be in transition from open prairies to densely timbered tracts. They were sparsely cov- ered with several species of oak trees and with dense undergrowth of shrubs and annuals. Treatises on plant material, published in the Illinois State Agricultural Society [ 145] 146 Transactions for 1856-1857, indicated the rapidly increasing interest in applied botany. These treatises, presented by O. Ordway (1857) of Lawn Ridge, H. L. Brush (1857) of Ottawa, Samuel Ed- wards (1857) of La Moille, J. P. Eames (1857), Dr. Frederick Brendel (1857) of Peoria, and I. A. Lapham (18570) of Milwaukee, Wisconsin, dealt with sev- eral phases of research, including culture and cultivation. The types of plants studied were evergreens, flowers, grasses, grain fruits, and vines. At La Moille, Edwards started plant- ing evergreens in 1845 and, by 1857, had planted more than 125,000 plants ob- tained from forests of Minnesota, Wis- consin, Michigan, Indiana, Ohio, New York, and upper Canada and also some obtained from eastern and European nurseries—in all, more than 25 species of evergreen plants. He was most favor- ably impressed with the growth of Nor- way and black spruces, Austrian, Scotch, and white pines, and balsam fir. Siberian and American arbor vitaes and red cedar, he found, were excellent for screening. Other species he mentioned that suc- ceeded well in this climate and soil were Irish, Swedish, and savin junipers, red spruce, and a variety of pine from Ten- nessee. Hemlock was subject to winter injury; Douglas spruce, cedar of Leba- non, deodar cedar, silver fir, English and Irish yews, Himalayan and Araucarian pines, and Chinese arbor vitae did not survive the winters. In 1857 Dr. Cyrus Thomas, with the help of S. Burtley, started studying the flora of the Murphys- boro region of southern Illinois (Thomas 1857). EARLY ACTIVITIES Among the persons interested in botany who were active in organizing the Illinois Natural History Society were M. S. Bebb, Dr. Frederick Brendel, E. Hall, Robert Kennicott, Dr. S. B. Mead, Dr. Cyrus Thomas, and Dr. George Vasey. Much of the information obtained by them on the flora of Illinois was pub- lished in the Illinois Natural History Society Transactions. When the original purpose in organizing the Natural His- tory Society was set forth as the advance- Inurinois NAturRAL History SurvEY BULLETIN ment of science, botany was mentioned along with entomology and geology. In succeeding years special interests de- veloped in the field of botany, as indicated by the published works of Brendel, Bebb, Vasey, Thomas, Edwards, G. W. Minier, Henry W. Bannister, and H. H. Bab- cock from 1859 to 1887, most or all of whom were members of the Natural His- tory Society. Brendel was a_ prolific worker and was the author of numerous articles published over a period of nearly 30 vears (Brendel 1859a, 18594, 1859c, 1859d, 1860, 1861, 1870, 1876, 1887). These articles included information on the flora of Peoria and other areas of the state. Brendel was interested in shrubs and forest trees, especially the oaks. Also, he wrote on rare plants in the state and on a peculiar growth of the water lily. It is significant that an article by him, “The Tree in Winter,” was one of the first articles published in the Bulletin of the Illinois State Museum of Natural History. Bebb (1859) published a list of 44 species of plants occurring in the northern counties of the state; his list was an addi- tion to the catalog by Lapham (1857a). Vasey’s interest in different phases of botany is indicated by his papers (Vasey 1859, 1861, 1870a, 1870b). Among these reigagal Vol. 27, Art. 2m papers were studies on flora, including — mosses of the state and maritime plants of the Great Lakes and interior regions; also, descriptions of two plants new to Illinois. When Thomas (186lc) proposed a plan for a natural history survey of IIli- nois, he suggested that this survey include a systematic cataloging of the flora and 2 fauna of the state and that the data be — published so that the same work would not need to be repeated by others. Ban- nister (1868) described prairie and forest plants of Cook County, and Babcock (1872) described the flora of the Chicago — area. John Wolf and Elihu Hall prepared a list-of mosses, liverworts, and lichens of the state. This list, which was pub- lished in the Bulletin of the Illinois State Laboratory of Natural History, contained 115 genera and 386 species (Wolf & Hall 1878). Wolf was on the staff of the State Laboratory of Natural History in 1880. December, 1958 By 1865 concern was voiced that trees of the state were being used so rapidly for lumber that cultivation and planting of trees should be promoted. Minier (1865, 1868) published two articles on the cultivation of forest trees. In his sec- ond article Minier (1868:279) stated: “Tree planting in I]linois is no longer for ornament merely. It has become a neces- ey... |. If, then, the coming genera- tions are to be supplied with timber, the present must plant it for them.” Edwards (1868) recommended planting trees but pointed out that black locust trees that had been planted 25 years earlier had been seriously damaged by borers. Specific interest in some specialized groups of plant life in Illinois became evident shortly after 1870, as indicated by the works of Thomas J. Burrill on plant diseases caused by fungi and bac- teria. Burrill, on the staff of the Illinois Industrial University, the University of Illinois, and the Illinois State Laboratory of Natural History, was a close associate of Stephen A. Forbes for 27 years. He reported on fungus diseases in the 1870’s, especially on fungi which cause diseases of vegetable and fruit crops (Burrill 1874, 1876, 1877). Later he reported that the widespread blight of pear trees was caused by a bacterium (Burrill 1881). This, the first report that bacteria cause plant diseases, opened up a new field of research. Burrill continued to publish articles on fungi and_ bacteria that cause plant diseases and in 1885 he published a 115-page article, in the Bul- letin of the Illinois State Laboratory of Natural History, on the parasitic fungi of Illinois (Burrill 1885). Following 1885 botanical research ex- panded in scope to include all types of native and naturalized plants in the state. The work of Burrill while on the staff of the Illinois State Laboratory of Natural History from 1885 to 1892 in- dicates the expanding development of botanical interest in forest trees and dis- eases of crop plants. Burrill prepared papers not only on fungal and bacterial diseases of crop plants but also on forest, roadside, and street trees, biology of silage, and extermination of the Canada thistle (Burrill 1886, 18875, 1887c, 1888, 1889a, 1889, 1890). Among others em- Carter: APPLIED BOTANY AND PLANT PaTHOLOoGy 147 ployed as botanists on the staff of the State Laboratory of Natural History were Rachel M. Fell, Arthur B. Seymour, Benjamin M. Duggar, and Arthur G. Vestal. A well-illustrated, 142-page article on edible and poisonous mushrooms in IlIli- nois, prepared by Walter B. McDougall (1917), was published in the Bulletin of the Illinois State Laboratory of Natural History. This article contains many plates illustrating the mushrooms de- scribed and is exceedingly useful in dif- ferentiating between poisonous and edible mushrooms. Studies on plankton were carried on by C. A. Kofoid from 1895 to 1900 and by Samuel Eddy from 1925 to 1929. Ko- foid’s extensive work on the plankton of the Illinois River was published in the Bulletin of the Illinois State Laboratory of Natural History (Kofoid 1903, 1908). Eddy’s work dealt with plankton of Lake Michigan, the Sangamon River, and some sinkhole ponds in southern Illinois; this work was reported in the Bulletin of the Illinois Natural History Survey (Eddy 1927, 1931, 1932). Interest in the ecology of vegetation and plant associations of sand prairies in Illinois is indicated by the papers of C. A. Hart and H. A. Gleason (Hart & Glea- son 1907; Gleason 1910), F. C. Gates (1912), and Vestal (1913) published in the Bulletin. Information was obtained not only on the general plant associations but also on the physical environment, the blow-out formations, the blow-sand com- plex, the blackjack oak associations, and some adaptations of the plants to the en- vironment. Although Minier (1865, 1868) and Edwards (1868) were concerned about the rapid destruction of trees in the 1860’s, it was not until 1911 that a policy on forest management was recommended by R. C. Hall and O. D. Ingall. In an article on forest conditions in Illinois, published in the Bulletin (Hall & Ingall 1911), they recommended (1) adoption of an adequate state fire-protection sys- tem, (2) inauguration of an education campaign for scientific and practical forest management, and (3) further investiga- tion of the forest problems involved and development and extension of wood lots 148 Ittinois NarurAL Hisrory Survey BULLETIN in the state. Also, they proposed a forest law for the state. Later, Forbes and Rob- ert B. Miller (Forbes 1919a, 1919); Forbes & Miller 1920) pointed out that the forests of Illinois were being rapidly destroyed and that only very few of the remaining forests were being properly handled. Miller (1923) made the first extensive report on a survey of the forests of Illinois; the report was published in the Bulletin of the Illinois Natural His- tory Survey. classification ; history and types of forests and important trees in the forests; uses of forest trees in milling and logging op- erations, wood-using industries and veneer industries; production of charcoal, ties, and mine timbers; and adverse effects of fires, erosion, and grazing on forested areas. The second extensive report on a forest survey of Illinois was made by Herman H. Chapman and Miller and published in the Bulletin (Chapman & Miller 1924). In this report the economic value of the forests and the forests as a crop were emphasized. The uses made of forest trees were discussed, and a policy of proper management of the forests to pre- vent the continued decimation of timber was outlined. C. J. Telford (1923), a Natural His- tory Survey forester, reported on height and growth studies on certain bottomland tree species in southern Illinois. He found that naturally stocked plantings of syca- more, cottonwood, pin oak, and maple produced better growth than did plant- ings of most other species in the bottom- lands. Telford (1926) reported on the third forest survey of Illinois. In this report, which included descriptions of the forests in the state and data on growth of in- dividual trees and yields of different types of trees, he reviewed the proposed forest policies given in the two previous forest surveys of the state and urgently recom- mended setting up an educational pro- gram to promote the development of farm wood lots, the protection of the then present forests, and the reforestation of much of the waste land, estimated to total 1,577,663 acres. These reports on forests of Illinois stimulated interest in the preservation and The survey covered land Vol. 27, Art. 2a expansion of the forest resources of the state. A forestry program was carried on and expanded by the extension foresters who succeeded Telford and who were employed jointly by the Natural History Survey and the Department of Forestry of the University of Illinois. They were L. E. Sawyer, J. E. Davis, and Li Bp Culver. Since 1954 the Natural History Survey has not participated in this for- estry program. By 1900 special emphasis was being directed toward control of plant diseases in Illinois. This trend was emphasized by some of Burrill’s papers, such as that on spraying for the control of bitter rot (Burrill 1903). As interest in this field continued to increase, it became evident that a systematic study of plants and plant diseases in Illinois should be inau- gurated. In 1921 a botanical section was established within the framework of the Natural History Survey by the appoint- ment of Leo R. Tehon as the first botanist. Under the direction of Tehon as bot- anist in charge of the Section of Botany from 1921 to 1935 and as botanist and head of the Section of Applied Botany and Plant Pathology from 1935 until his untimely death in 1954, botanical re- search expanded to include work not only in the field of general botany but espe- cially in the fields of mycology, plant pathology, and taxonomy. The number of technically trained scientists on the staff was increased from | in 1921 to 10 in 1954. Tehon’s broad background and train- ing and his mastery of the various fields of research carried on in the botanical — section are indicated, in part, by his many and varied publications. Tehon described many new genera and species of fungi, most of them in a series of six articles under the title “Notes on the Parasitic Fungi of Illinois’ (Tehon 1924, 1933, 1937b; Tehon & Daniels 1925, 1927; Tehon & Stout 1929). Also he wrote “A Monographic Rearrangement of Lophodermium” and “New Species and Taxonomic Changes in the Hypoderma- — taceae” (Tehon 1935, 1939d). He de- scribed diseases affecting economic crops, including those of fruits, vegetables, grain and forage crops, and diseases of ornamen- me Wien ea December, 1958 tal plants, especially trees (Tehon 1925, 1939}, 1939c, 1943; Tehon & Stout 1928; Tehon & Jacks 1933; Tehon & Boewe 1939; Tehon & Harris 1941). He was especially interested in developing methods and principles for interpreting the phenology of crop pests (Tehon 1928). Tehon’s botanical interests are indi- cated by such publications as The Native and Naturalized Trees of Illinois (with Robert B. Miller), Rout the Weeds, Pleasure With Plants, Fieldbook of Na- tive Illinois Shrubs, The Drug Plants of Illinois, and (with collaborators) Illinois Plants Poisonous to Livestock (Miller & Tehon 1929; Tehon 1937a, 1939a, 1942, 1951a; Tehon, Morrill, & Graham 1946). He was a linguist and translated Gio- vanni ‘Targioni ‘Tozzetti’s Alimurgia, part V, 1767, an Italian article of 156 pages on diseases of wheat and other cereals; the translation was published in English as Phytopathological Classics No. 9 (Tehon 1952a). RECENT ACTIVITIES The early work in the Section of Bot- any consisted not only of a survey of the plant diseases in the state but the de- velopment and co-ordination of research in botany, with special emphasis on plant diseases and the establishment of a her- barium, which included a plant disease collection and a native plant collection. In an annual report Forbes (1923:386) described the work of the botanical sec- tion as follows: Beginning in July, 1921, active work has been done throughout the State on the fungus parasites of the crop plants, many of which are highly destructive and difficult to control. It was the principal first object of this in- quiry to make accessible existing knowledge of the plant diseases of the State and of their distribution in Illinois and their destructive- ness, and to ascertain whether known meth- ods of protection against them are generally used, this to be followed by measures intended to make crop growers acquainted with the most important preventable diseases and the losses due to them and with established means for their prevention and control. To aid in the work of the Section of Botany the co-operation of 135 unpaid field observers was obtained to watch for plant diseases and to report any unusual outbreaks of diseases occurring at any CarTER: APPLIED BOTANY AND PLANT PATHOLOGY 149 time. The information obtained included the crops attacked by each disease, the stage of growth of the crop when at- tacked, the damage caused, the first date of appearance of disease, the amount of damage to the crop, the control measures used, and the prevalence and destructive- ness of each disease. As the work of the Section of Botany continued to expand, greater emphasis was placed on the application of research information for the control of plant dis- eases, and in 1935 the name of the section was changed to Section of Applied Bot- any and Plant Pathology. At this time the activities of the section were divided into four main groups, namely, (1) Plant Disease Survey, (2) Botanical Sur- vey, (3) Shade and Forest Tree Pathol- ogy, and (4) Floricultural Pathology. The first full-time staff member to con- duct research on floricultural pathology was not appointed until 1939. Plant Disease Survey The plant disease survey, started by Tehon in 1921, included a survey of the diseases of all crop plants of Illinois, with special emphasis on field crops and fruit crops. Among the persons who have assisted in the plant disease survey since its beginning are Charles O. Peake, Charles L. Porter, O. A. Plunkett, Harry W. Anderson, Paul A. Young, Gilbert L. Stout, and G. H. Boewe. Constantine J. Alexopoulos and Leo Campbell collected numerous plants around peach orchards in southern Illinois counties as part of a study of possible hosts of the peach yel- lows virus. Field Crop Diseases. — After the establishment of the Section of Botany in July of 1921, flag smut of wheat was the first major disease studied. This dis- ease, discovered in Illinois in 1919, was causing serious losses of wheat in the East St. Louis area. The limits of the disease in the state were determined, and effective control measures, including a quarantine, were enforced. By following rigid quarantine regulations, which re- quired burning all straw and treating all grain sold for seed, and by introducing varieties of wheat resistant to the disease, it was possible to eliminate flag smut. The effectiveness of this control program 150 Intinois NaArurAL Hisrory Survey BULLETIN prevented the disease from spreading over the whole soft wheat area. Other activities of the Section during the 1920's included warning cotton grow- ers in southern Illinois of the diseases to be encountered, discovering and destroy- ing the only known instance of alfalfa infestation by the stem nematode, and collecting data on the prevalence and de- structiveness of stinking smut of wheat. By 1923 it had been determined that 165 diseases affecting 44 different crops were present in the state. In that year the estimated reduction in yield of Illinois wheat caused by five diseases (leaf rust, stem rust, stinking smut, loose smut, and scab) was 7,712,800 bushels, valued at $11,837,000. In most years of the past decade the estimated annual losses from diseases of iy ie ee Vol. 27, Art. 2 Illinois wheat have been 5,500,000 to 7,150,000 bushels. The greatest loss in a single year, 7,150,000 bushels, valued at $15,158,000, occurred in 1950. In 1953, a year of minimum loss, the esti- mated reduction in yield was only 368,- 800 bushels, valued at $586,400. The estimated annual losses resulting from diseases of corn usually are greater than the losses resulting from diseases of wheat. In the past decade the lowest esti- mated reduction in corn yield, 54,250,000 bushels, valued at $82,450,000, occurred in 1952 and the highest estimated reduc- tion in yield, 168,100,000 bushels, valued at $198,358,000, occurred in 1949. The average annual estimated reduction in yield of corn in Illinois during the past decade was 90,626,100 bushels, valued at $112,139,072. _ Homemade mixer used about 25 years ago by plant pathologists of the Illinois Natural History Survey to demonstrate effectiveness of chemical treatments in control of seed-borne dis- eases of small grains. December, 1958 CARTER: The plant disease survey not only in- dicates the annual losses caused by plant diseases but reveals diseases new in the state and the sudden and _ widespread damage caused by any disease that has caused only minor damage in preceding years. Downy mildew of alfalfa appeared generally in the state and was abundant in the extreme north in 1924. This disease had not been seen in Illinois previous to that year. A new leaf spot of cowpea was discovered in Clinton County in 1927. In an article by Stout (1930), 16 new fungi found on corn in Illinois were described. Downy mildew of soybean, first reported in Illinois in 1929, caused considerable damage in 1935, when it was found in 12 counties. Brown stem rot of soybean, first recognized in the state in 1944, sud- denly became widespread and destructive in 1948. This outbreak of the disease fol- lowed a fortnight of low temperatures, which ended on August 10. Septoria leaf spot of broom corn was discovered in IIli- nois in 1949 and was very destructive in several fields west of Galton in Douglas County. Diseases recorded for the first time in Illinois in recent years include ergot on timothy, bacterial blister spot on apple, charcoal rot on pepper, and downy mil- dew on wheat in 1952; basal glume rot on barley, anthracnose on sweet clover, and rosette on cherry in 1954; Ascochyta leaf spot on rhubarb and bacterial leaf spot on mulberry in 1955; powdery mildew on apple, ergot on oats, Helminthosporium leaf spot on red top, and Gloeosporium leaf spot on currant in 1956; and Phy- tophthora root rot on alfalfa, Phytoph- thora stem rot on lily, Cercospora leaf spot on Deutzia, Abelia, ornamental gooseberry, and wafer ash, downy mil- dew on cucumber, squash, and water- melon, rust on apricot, anthracnose on iris, powdery mildew on pecan and frag- rant sumac, Badhamia slime mold on timothy, Herptobasidium scorch on bush honeysuckle, and Phyllachora tar spot on lespedeza in 1957. In the plant disease survey, not only are the various kinds of crops examined but many plants in many fields of the same crop are examined each summer. For instance, in 1949, data on prevalence and severity of wheat diseases were ob- AppLiep BorANy AND PLANT PATHOLOGY 151 tained by examination of plants in 42 wheat fields that totaled 1,033 acres and that were located in 38 widely scattered counties of the state. Another phase of the plant disease sur- vey is that of forecasting the anticipated occurrence and seriousness of plant dis- eases. This forecasting has been notably effective for Stewart’s disease of corn. The bacterium that causes Stewart’s dis- ease overwinters chiefly in the body of the adult corn flea beetle (Chaetocnema puli- caria). The mortality rate of the flea bee- tle is affected by weather conditions dur- ing hibernation. Although forecasting the early season or wilt stage of Stewart’s disease had pre- viously been worked out by others, fore- casting the late season or the leaf blight stage was worked out by G. H. Boewe. Making use of data accumulated in the 5-year period 1944-1948, Boewe found that a winter temperature index rather accurately forecast the late season develop- ment of Stewart’s disease. The index for any growing season was based on the sum of the mean temperatures of the previous winter months of December, January, and February. While early season epi- demics do not develop unless the index is 90 or above, light to moderate late sea- son epidemics develop when the indexes are between 80 and 85, and moderate to heavy late season epidemics when the in- dexes are above 85. No disease or only a trace of disease develops when the in- dexes are below 80. Forecasting of the severity of disease each year has been quite accurate. The appearance and spread of new dis- eases on crops in Illinois often are re- corded first as a result of the annual sur- vey made for plant diseases. Aid to farm- ers in combating these diseases is made through warnings and through publica- tions such as Diseases of Small Grain Crops in Illinois (Boewe 1939). Fruit Diseases.—Of the many dis- eases that affected fruit trees in the state each year during the early years of the plant disease survey, the most common and destructive were scab, shothole, brown rot, and leaf curl of peach; fire- blight, frogeye, and blotch of apple; fire- blight, leaf blight, and leaf spot of pear; and shothole and leaf spot of cherry. 152 I-tinois NarurAL History SurRvEY BULLETIN In early August of 1927 Professor M. J. Dorsey of the University of Illinois found, in a large orchard near Centralia, the first authentic case of peach yellows in Illinois. By 1929 the disease had spread to 37 trees scattered in 11 orchards located in Jefferson, Marion, Pike, and Pulaski counties. In recent years peach yellows has not been observed in Illinois. Diseases which are destructive to the peach crop and which have appeared an- nually in recent years are scab, brown rot, shothole, and peach leaf curl. During the early years of the plant dis- ease survey, nailhead canker was a serious disease of apple trees. However, this dis- ease disappeared from the orchards of the state when growers eliminated those va- rieties susceptible to the disease. ‘The major destructive diseases of apples which have continued to appear annually are scab, fireblight, frogeye, and blotch. Mil- dew has increased in destructiveness in recent years because the sulfur fungicides which controlled the disease in the early years have been replaced by new types of fungicides; these new materials more ef- fectively control the other diseases of apples. Cedar apple rust, which was prev- alent and destructive for many years, is controlled satisfactorily at present by some of the recently developed fungicides, fer- bam plus sulfur on the deciduous hosts, Elgetol and acti-dione on the evergreen hosts. Many pear orchards in the state have been severely damaged or destroyed by fireblight. At present there is hope that this disease can be effectively controlled by some of the new antibiotic sprays. Other diseases destructive annually to pear trees are leaf blight and leaf spot. The disease most destructive to cherry trees in the state is shothole. Yellowing, necrosis, and premature leaf drop, caused by this disease, gradually reduce the vigor of affected trees and, eventually, the qual- ity and quantity of cherries produced. Diseases that may appear annually on other fruit crops are bacterial spot and black knot of plum; black rot, downy mildew, and powdery mildew of grape; crown gall and rust of blackberry; an- gular leaf spot of currant; leaf spot, leaf scorch, and yellows of strawberry; an- thracnose of raspberry, currant, and goose- Vol. 27, Art. 2 berry; and Septoria leaf spot of black- berry and raspberry. Although many of these diseases are not destructive each year, they cause serious losses in some years. Vegetable Diseases.—Although vegetable crops are affected by many dis- eases, only a few of the diseases cause serious losses annually. The most com- mon and destructive diseases in Illinois are bacterial blight, halo blight, and mosaic of bean; yellows of cabbage; Ascochyta leaf spot, Fusarium wilt, and powdery mildew of pea; Fusarium wilt, mosaic, and bacterial leaf spot of pepper; early blight, Fusarium wilt, black leg, and scab of potato; and early blight, Fusarium wilt, and Verticillium wilt of tomato. Botanical Collections The first of the present botanical col- lections of the Natural History Survey was started in a small way in 1921. At that time the collection of plant disease fungi of the Natural History Survey was separated from the collection of the Uni- versity of Illinois. The vascular plants collected with State Laboratory funds and with Natural History Survey funds previous to 1921 were left in the her- barium of the University of Illinois. Plant Disease Collection.—The earliest reported specimens in the plant disease collection of the Natural History Survey are several hundred specimens col- lected, 1918-1921, by H. W. Anderson of the University of ‘Illinois. Collection, identification, and preservation of such specimens were expanded rapidly during the four summers of 1921 through 1924, when special emphasis was placed on ob- taining information on the plant disease situation of the state. To conduct this plant disease survey, one to four men were employed full-time each summer to collect specimens of diseased plants in each county of the state. This activity resulted in adding over 18,000 plant dis- ease specimens to the collection. Among these specimens were five plant diseases new to the state and 18 species of plant parasites new to science. In 1924 this collection contained type specimens which represented three genera and 73 species of plant-inhabiting fungi December, 1958 first known for their occurrence in IIli- nois. Although some specimens have been added to the plant disease survey collec- tion by all botany staff members since 1924, most of the specimens have been added by Boewe, the plant pathologist now responsible for the plant disease sur- vey. Specimens of special interest sent to the laboratory for diagnosis of disease are added to the collection. Gilbert L. Stout was the first plant pathologist to devote full time to plant disease survey work. He was succeeded by Boewe in 1930. In this work diseased plant material is carefully examined to determine the specific disease involved. Many specimens are collected not only as characteristic examples of the disease but for further study in the laboratory to determine the organism causing the dis- ease. Specimens of diseases new to the United States, Illinois, or a county of the state are preserved in the plant disease collection. As of April, 1958, the plant disease collection contained 32,624 specimens. Al- though this collection contains mostly fungi that cause plant diseases, it also contains specimens affected by disease- causing bacteria, viruses, and noninfectious agents. Information on new diseases has been published in Mycologia, Phytopa- thology, and the Plant Disease Reporter. Vascular Plant Collection.—The collection of vascular plants in Illinois by Natural History Survey staff members was begun in 1927 with the establish- ment of a project on the accumulation of plants of the state. By 1931 three addi- tional projects had been added: mainte- nance of a herbarium containing repre- sentative plants of Illinois, maintenance of a bibliography of Illinois plant records, and maintenance of a card record of the occurrence of plants in [llinois. The first systematic collection of IIli- nois vascular plants for the Natural His- tory Survey was made by James Schopf, who collected 1,676 specimens during the summer of 1931. In September of 1931 Dr. Herman S. Pepoon joined the Survey staff. Pepoon, with the assistance of E. G. Barrett, collected 1,300 specimens. After Pepoon left the Survey in 1933 the ac- cumulation of Illinois plants was added to the duties of the plant pathologists. Carrer: APPLIED BoraANy AND PLANT PATHOLOGY 153 Much of the collecting was done by Boewe in conjunction with his work on the plant disease survey. In October of 1946 R. A. Evers joined the staff and was assigned the botanical survey work. His work is devoted almost exclusively to a study of the flora and vegetation of the state. Since 1946 he has collected plant specimens annually in each of the 102 counties of the state. Previous to 1947 the number of speci- mens in the vascular plant collection was increased by gifts of specimens from R. A. Dobbs of Geneseo, R. A. Evers then of Quincy, and G. D. Fuller of the Illinois State Museum. Also, the herbarium of Charles Robertson of Carlinville was ac- quired. Since 1947, plant specimens, as gifts or exchanges, have been received from Franklin Buser (graduate student), James Long of Amboy, Dr. V. H. Chase of Peoria, Dr. Sidney Glassman of the University of Illinois staff at Navy Pier, Chicago, Dr. John Voigt of Southern Illinois University, Dr. John Thieret of the Chicago Museum of Natural History, and others. Thirteen species of plants have been added to the known flora of Illinois by Natural History Survey staff members since 1947. They are Daucus pusillus, Medicago arabica, Setaria faberti, Spec- ularia biflora, Rudbeckia missouriensis, Heliotropium tenellum, Eriochloa villosa, Dicliptera brachiata, Cyperus lancas- triensis, Haplopappus ciliatus, Verbascum virgatum, Helianthus angustifolius, and Jussiaea leptocarpa. Publications resulting from the collec- tion of vascular plants of Illinois include a 339-page bulletin on native and nat- uralized trees of the state (Miller & Tehon 1929), two fieldbooks, one on wild flowers (Anon. 1936) and one on native shrubs (Tehon 1942), and articles on genera and species of Illinois plants, including several new to the state (Evers 1949, 1950, 1951, 1956; Evers & Thieret 1957). Identification and preservation of vas- cular plants in the Natural History Sur- vey herbarium were under way to a limited extent by 1927. In succeeding years students have been employed to mount specimens for the herbarium. In 1936 Richard A. Schneider was em- 154 Intinois NAtrurAL History SurvEY BULLETIN ployed to identify the accumulated col- lection of plant specimens. Although col- lection, identification, and preservation of vascular plant specimens were curtailed during World War II, the herbarium contained 13,749 specimens in May of 1943 and 17,339 specimens in October of 1946. The abundant collection of plant material in succeeding years has in- creased the number of vascular plant specimens in the herbarium to 70,600, and approximately 8,000 additional speci- mens are on hand to be added to the herbarium. Under present conditions three student assistants are employed to prepare the plant material for placing in the herbarium. A card index is main- tained of all plant specimens. The bibliography of Illinois plants, started previous to 1931, is not up-to-date because of lack of funds and lack of as- sistants to examine the literature. In co-operation with L. E. Yeager, R. E. Yeatter, A. S. Hawkins, and D. H. Thompson, fellow staff members doing wildlife or fisheries research, botanists made a census of waterfowl food plants of the Chautauqua Drainage District, car- ried on a survey of Illinois plants useful to wildlife as food or cover, and con- ducted experiments on propagation of plants useful to wildlife as food or cover. A collection of 848 samples of seeds was developed for identification of seeds in- gested by waterfowl. Activities pertaining to the botany of Illinois include preparation of manu- scripts designed for publications, mainly of an educational or popular type. These publications are on such subjects as noxious weeds, directions for the study and identification of plants, drug plants (Tehon 1937a, 1939a, 1951a), plants poi- sonous to livestock (Tehon, Morrill, & Graham 1946), and vegetation of hill prairies in the state (Evers 1955). The publication on the vegetation of hill prairies is a report on an extensive ecological study of 61 prairies on the brow slopes of bluffs of the Mississippi River from East Dubuque to southern Illinois, the Illinois River from the big bend near Hennepin to Grafton, and the Rock and Sangamon rivers. This type of publication by the Natural History Sur- vey is a continuation of those published Vol. 27, Art. 2 earlier by the State Laboratory of Nat- ural History. Shade and Forest Tree Pathology The earliest reported conspicuous dying of trees in Illinois was among the elms in Normal-Bloomington and Champaign in the period 1883-1886 (Forbes 1912a). The next reported conspicuous dying among elms occurred from 1907 through 1911, when many trees succumbed in - southern Illinois. During this period con- spicuous losses of elms were reported in Cairo, Carbondale, Centralia, Clayton, Du Quoin, Edwardsville, Fairfield, Ga- latia, McLeansboro, Mount Vernon, Quincy, Robinson, Sumner, and Van- dalia. These 14 towns are located in 13 counties of western and southern Illinois. Although the cause of the dying of elms during these two periods was not de- termined, it was suggested that some dis- ease might be involved. Dying of feeder roots, wilting of foliage, and dying of terminal twigs was followed by death of the trees. Many of the affected elms in southern and western I[]linois were heavily infested with the elm borer, Saperda tri- dentata, and the red elm bark weevil, Magdalis armicollis, called by Forbes the reddish elm snout-beetle. Elm Diseases. — A few years after the establishment of the Section of Bot- any in 1921, reports and inquiries were received about a widespread wilting of elms growing in commercial nurseries and in decorative plantings, most of them in northern Illinois. Some special exam- inations made of these trees by Dr. Christine Buisman of Holland, an expert on elm diseases, revealed that the malady was not Dutch elm disease. Research on the cause and control of this wilting was started in 1930. Until May, 1934, the work was carried on by graduate students —H. A. Harris, Leo Campbell, J. A. Trumbower, and A. S. Peirce. In May of 1934 J. C. Carter joined the staff as a full-time plant pathologist to study dis- eases of trees. Although intensive study of the elm wilt problem was continued for several years, other elm diseases and diseases of other species of trees were studied as they became evident. From 1934 to 1950 research on tree diseases was carried on by Carter. With the expan- December, 1958 sion of the tree disease research program in 1950, additional plant pathologists were added to the staff. The recent re- search program has been carried on by four plant pathologists, Richard J. Campana, Walter Hartstirn, Eugene B. Himelick, and Dan Neely. In the studies on the cause and control of the wilting of elms, it was found that several fungi were involved. Although the first report on this work (Harris 1932) indicated that several fungi were capable of causing the wilting, later studies showed that most wilting was caused by the Dothiorella wilt fungus and it was most serious in plantings of trees that were weakened by overcrowd- ing and by repeated annual defoliations from heavy infestations of the spring cankerworm. Spraying with copper and sulfur fungicides was not effective in noticeably reducing or preventing wilting. This spraying included dormant and foliar applications, in some years as many as one dormant and seven foliar sprays. Al- though research failed to find a control for this type of wilting of elms, it showed that applications of either sulfur or cop- per fungicide in June and early July gave excellent control of the black leaf spot disease (Trumbower 1934). Control of this disease in commercial nursery plant- ings of elms increased the annual growth; sprayed trees made as much growth in 4 years as unsprayed trees made in 5 years (Carter 1939). A conspicuous and widespread dying of elms which became evident in Danville and Peoria in the late 1930’s appeared in other areas in succeeding years. It now is widespread and destructive throughout the southern two-thirds of the state. North of Peoria, Bloomington, Cham- paign, Urbana, and Danville, it occurs in only a few isolated places. The north- ernmost isolated infection is in Rockford. This disease, called phloem necrosis and described as a virus disease in 1942 (Swingle 1942), has killed thousands of elms in Illinois and is one of the two major diseases that continues to kill thou- sands of elms annually. In Champaign and Urbana phloem necrosis killed 2,460 trees in a period of 14 years; this number represents over 16 per cent of the total elm population in the two cities. Mount CarRTER: APPLIED BoTANY AND PLANT PATHOLOGY 155 Pulaski, with an elm population of ap- proximately 600 trees in 1940, had all but 19 elms killed by the disease by Sep- tember of 1948. During the late 1930’s and early 1940’s, in investigations of the wilting and dying of elms, several fungi capable of producing cankers were studied. Can- ker diseases usually were confined to a few trees in a planting of elms but were found in plantings in widely scattered locations in the state. The cankers caused by species of Cytosporina, Phoma, and Coniothyrium were prevalent only on American elm. The canker caused by Tubercularia ulmi affected the Asiatic species of elm, Ulmus pumila and U. parvifolia. A serious and widespread wilting of elms in Hinsdale was brought to the at- tention of the Natural History Survey by Village Forester W. E. Rose in 1939. Intensive research on these elms resulted in the discovery of a bacterial disease called wetwood (Carter 1945). Wet- wood is a chronic disease that affects most elms but usually does not result in the death of affected trees. Ulmus pumila is especially susceptible to wetwood. Re- search on this disease is described in a 42-page article under the title ““Wetwood of Elms” (Carter 1945). The National Arborist Association awarded a citation to the author in “recognition of his ex- cellent work’ reported in the article. This work the Association “considered the outstanding research during 1945 on shade tree preservation.” Dutch elm disease is the most destruc- tive disease of elms in I]linois. Although this disease was first discovered in the United States at Cleveland and Cincin- nati, Ohio, in 1930, it was not until 1950 that the first diseased elm was found in Illinois. Only one tree affected with Dutch elm disease was found in 1950, 11 were found in 1951, 24 in 1952, and over 500 in 1953. The numbers of counties in which the disease has been found each year were | in 1950, 4 in 1951, 9 in 1952, 15 in 1953, 55 in 1954, 74 in 1955, 86 in 1956, 94 in 1957, and 99 in 1958. The rapid destruction of elms by the disease is illustrated by the numbers of trees af- fected each year in Champaign and Ur- bana. Only one affected tree was found in 156 Intinois NATURAL History SURVEY Vol. 27, Art. 2 BULLETIN Plant pathologists of the Illinois Natural History Survey culturing sample of American elm suspected of being affected by the Dutch elm disease. Modern laboratory equipment enables the plant pathologists to substantiate field diagnoses. Urbana in 1951. The numbers of affected trees in succeeding years in Champaign and Urbana were 11 in 1952, 164 in 1953, 694 in 1954, 1,805 in 1955, 1,836 in 1956, and 2,116 in 1957. These 6,627 diseased elms represent over 44 per cent of the elm population of Champaign and Urbana when the disease was first found there. The Natural History Survey has had one full-time plant pathologist conducting research on elm diseases, including Dutch elm disease, since July, 1951: Ralph W. Ames in 1951 and 1952 and Richard J. Campana in 1952 and later. Oak Diseases.—Numerous inquiries about diseases of oak during the 1930’s led to a special investigation which culmi- nated in the publishing of a preliminary report (Carter 1941). Although a dozen fungi were associated with the develop- ment of canker and dieback diseases of oak in the field, only one fungus, Dothio- rella quercina, caused canker and die- back under controlled experimental con- ditions. The other organisms appeared to produce canker and dieback only on trees previously weakened by adverse growing conditions. Oak wilt, the most destructive and widespread disease of oak trees in the United States, was not found in Illinois until 1942, when a few affected trees were discovered in Ingersoll Park at Rockford in Winnebago County. In fol- lowing years the disease was found in other counties; by 1958 it was killing trees in 70 of the 102 counties of the state. Extensive research on the disease was started in 1950 with a grant of money December, 1958 from the Forest Preserve District of Cook County, Illinois. A graduate stu- dent at the University of Illinois, E. A. Curl, was employed on a half-time basis. A second grant of money was received from the Forest Preserve District in 1951. Also in 1951, funds were obtained from the National Oak Wilt Research Com- mittee of Memphis, Tennessee, composed of 10 hardwood industries, and from state appropriations for research on the dis- eases of trees. ‘These funds made it pos- sible to add three plant pathologists in 1951 to conduct full-time research on the oak wilt disease. The men employed were Bert M. Zuckerman, George J. Stessel, and Paul F. Hoffman. Additional funds were obtained from the National Oak Wilt Research Committee in 1952, 1953, and 1954. Funds appropriated by the state have continued to be a part of the Natural History Survey’s regular budget. These funds have made it possible to em- ploy additional plant pathologists to do research on oak wilt and other tree dis- eases. In 1953 four men full-time and two men half-time were conducting re- search on oak wilt. At present, with only state funds to support the research on oak wilt, three full-time regular staff mem- bers are continuing research on this dis- ease. “The men who have helped to carry on this program include E. A. Curl (1950-1954), Bert M. Zuckerman, George J. Stessel (1951-1952), Paul F. Hoffman, Eugene B. Himelick (1952- 1954), Richard D. Schein (1952-1953), Norman C. Schenck (1952-1953), Irving R. Schneider, Harry Krueger (1954— 1955), Arthur W. Engelhard, James D. Bilbruck (1955-1958), John M. Ferris, R. Dan Neely, and Walter Hartstirn. Persons whose names are followed by dates were employed on research funds granted to the Natural History Survey by the Forest Preserve District of Cook County, Illinois, or by the National Oak Wilt Research Committee. The dates in- dicate the periods of employment. Hime- lick was employed on research funds granted by the National Oak Wilt Re- search Committee (1952-1954) before he was employed by the Survey. As a result of this extensive research program on oak wilt, many papers were published. The phases of research covered CarTER: APPLIED BOTANY AND PLANT PATHOLOGY 157 in these papers include laboratory studies on the morphology and physiology of the fungus (Zuckerman & Curl 1953) and isolation of the fungus from species of oak on which it had not been previously re- ported (Carter & Wysong 1951); green- house studies on host range (Hoffman 1953) and experimental transmission of the fungus by insects, mites, and squirrels (Himelick, Curl, & Zuckerman 1954; Himelick & Curl 1955, 1958); green- house studies on infection by and spread of C'*-labeled fungus in inoculated oaks (Zuckerman & Hoffman 1953; Hoffman & Zuckerman 1954) ; and field studies on distribution and spread of oak wilt in Illinois (Carter 1952), availability of oak wilt inoculum in the state (Curl 1953, 1955a, 1955b; Himelick, Schein, & Curl 1953), characteristic growth of the fungus under natural conditions (Curl, Stessel, & Zuckerman 1952), discovery of the perfect stage of the fungus in nature (Curl, Stessel, & Zuckerman 1953; Stessel & Zuckerman 1953), and effect of the fungus on oak fence posts (Walters, Zuckerman, & Meek 1955). Other Diseases of Trees.—Al- though oak wilt, elm phloem necrosis, and Dutch elm disease are the most de- structive tree diseases in the state, other diseases of trees and of shrubs have been sufficiently destructive to require the at- tention of plant pathologists of the Nat- ural History Survey. A wilt disease that affects many species of trees in Illinois is Verticillium wilt. It is known to affect 27 species of plants, including 7 varieties of woody ornamentals representing 19 genera. Of the 27 species of woody hosts of this disease, 12 were first reported in Illinois: black locust, catalpa, Chinese, English, and slippery elms, goldenrain tree, linden, magnolia, multiflora rose, tupelo, wayfaring tree, and yellow-wood. Maple, elm, and catalpa are frequently affected by this disease. Canker diseases found in Illinois affect different species of trees, including crab apple, hawthorn, juniper, maple, moun- tain ash, pine, poplar, redbud, spruce, sycamore, and willow. Rust diseases are widespread and destructive in some years. They include cedar apple rust, cedar- hawthorn rust, cedar-quince rust, pine needle rust, and poplar leaf rust. 158 Inuinois NatuRAL History SurvEY BULLETIN Foliage diseases which cause especial damage during cool, moist springs affect many species of trees. The most destruc- tive foliage diseases are anthracnose of ash, maple, oak, and sycamore; blotch of buckeye and horsechestnut; and leaf spot of elm, hawthorn, maple, oak, and walnut. Some trees decline and die each year because of unfavorable growing condi- tions that include physiological disorders, adverse weather conditions, and mechani- cal injuries. These conditions, as well as disease organisms, have received the at- tention of Natural History Survey plant pathologists. Research on the control of foliage dis- eases includes testing of numerous fungi- cides each year. In some years as many as 18 species of trees have been treated with fungicides and as many as 12 differ- ent fungicides have been tested on one or more species. An example of an effective control measure resulting from these tests is the use of organic mercury fungicides to control anthracnose of sycamore. Chemotherapy.—One phase of Nat- ural History Survey research on the con- trol of tree diseases relates to the effec- tiveness of various chemicals in prevent- ing fungi from infecting trees or from causing disease symptoms after they have infected the trees. The early studies were confined mainly to oak wilt; the present studies include diseases of several species of trees and especially oak wilt, Dutch elm disease, and Verticillium wilt of elm, maple, and other trees. Of the hundreds of chemical compounds tested, a few systemic fungicides and antibiotic ma- terials appear to be effective in preventing disease development. To obtain more in- formation on what happens when these materials are introduced into trees, plant pathologists are studying the physiology of trees as well as the physiology of the fungi. The staff members who have car- ried on this program are Paul F. Hoff- man, Eugene B. Himelick, Irving R. Schneider, John M. Ferris, and Walter Hartstirn. Floricultural Pathology Little research by the Natural History Survey was done in floricultural pathol- ogy before 1939. In response to numerous requests for help in dealing with disease Vol. 27, Art. 2 problems in floricultural crops, a_ pro- gram of research was initiated, and Don B. Creager was appointed to the staff in — September of 1939. This program, car- ried on by Creager for 5 years and con- tinued by J. L. Forsberg, included work — on diseases of greenhouse crops and field- — and garden-grown floricultural plants. Much attention was given to bulbous ornamental plants, which were being propagated extensively in Illinois for — shipment to other states. The early work was concerned with (1) obtaining as much information as possible about diseases important to IIli- — nois growers, (2) conducting research on diseases for which vital information on cause and control was lacking, and (3) rendering every possible aid to growers in the recognition and control of diseases — in their crops. As the work progressed more attention was given to developing disease control measures that would be — more effective than those that were being used. Crops which have received attention during the course of this work are ama- | ryllis, aster, azalea, begonia, calla, carna- : tion, chrysanthemum, gardenia, geranium, — gerbera, gladiolus, hollyhock, hydrangea, — iris, ivy, lily, orchid, peony, peperomia, periwinkle, petunia, poinsettia, rose, Afri- — can violet, snapdragon, stevia, stock, — sweet pea, tuberose, tulip, violet, and zinnia. Of these crops, gladiolus, rose, and carnation are grown in greatest — quantity, and, since all three crops are subject to a number of destructive dis- eases, more work has been done on them than on the other crops. Because of the serious losses due to diseases of gladiolus in the large com- mercial gladiolus growing area in Kan- kakee County, much research work has — been directed toward developing effective — control measures for these diseases. Prior to 1940, gladiolus corms generally were — not treated for disease control, but in re- cent years nearly all commercial gladiolus planting stocks in all parts of the United States have been treated with a fungicide before being planted. This practice has — developed largely as a result of the suc- — cess of experimental treatments by Illi- nois Natural History Survey pathologists. If these or other equally effective treat- December, 1958 ments had not been worked out, the gladiolus industry in Illinois would have succumbed. Among other noteworthy accomplish- ments achieved by Natural History Sur- vey pathologists in the field of floricul- tural pathology are the following: control of peony measles with an Elgetol ground spray (Creager 1941c, 1943a); control of black mold of rose grafts by chemical treatments (Creager 1941); control of balla rots by chemical treatments (Creager 1943+) ; establishment of viruses as the causes of peperomia_ ringspot (Creager 1941a), carnation mosaic and streak (Creager 1943c, 1944, Forsberg 1947), and coleus mosaic (Creager 1945) ; clarification of the Fusarium dis- ease complex in gladiolus (Forsberg 1955a); discovery of the vascular phase of the Curvularia disease of gladiolus (Forsberg 1957); discovery of scab on violets in Illinois (Forsberg & Boewe 1945); control of Thielavia root rot of sweet peas (Creager 1942); control of bacterial scab of gladiolus by use of soil insecticides (Forsberg 1955d). The value of an insecticide in the con- trol of bacterial scab of gladiolus became apparent in 1953 when gladiolus corms were treated with a seed protectant which contained an insecticide in addition to a fungicide. This treatment resulted in the production of corms free of bacterial scab and free of injury caused by white grubs. Results of this treatment supported observations that white grubs are instru- mental in spreading bacterial scab. Suc- ceeding tests showed that 25 per cent al- drin granules applied to the soil at the rate of + or 8 grams per 10 feet of row prevented white grub injury and _bac- terial scab. Identification and Extension During each growing season the Sec- tion of Applied Botany and Plant Pathol- ogy receives for examination and diagnosis several thousand samples of trees, shrubs, and other plants suspected by [Illinois residents of being diseased. Diagnosis results and treatment recommendations are sent as soon as possible to the persons sending the samples. Most of the samples received are from elms suspected of being affected with CARTER: APPLIED BOTANY AND PLANT PATHOLOGY 159 Dutch elm disease. To handle the labora- tory diagnoses requires the full-time help during the summer months of four ad- ditional persons: one mycologist, two lab- oratory technicians, and one stenographer. It is anticipated that the demand _ oc- casioned by Dutch elm disease for service from Natural History Survey personnel will continue indefinitely. To supply the demand from hundreds of communities and individuals through- out the state for information on identifi- cation, control, and other aspects of Dutch elm disease has occupied a major portion of the time of one plant pathol- ogist. Educational material on Dutch elm disease has been prepared for distribution ; this has included mimeographed leaflets on control and other phases of the disease, a series of news releases, kodachrome trans- parencies, black and white photographs, specimens, exhibits, maps, tables, and graphs. Technical advice and information were furnished the Illinois State Cham- ber of Commerce for two state-wide con- ferences on Dutch elm disease, one in 1955 and one in 1956. These conferences provided specific and detailed information on the nature and control of the disease. Outstanding authorities on Dutch elm disease in the United States were on the programs. Additional activities have in- cluded aid in field identification of the disease, aid in local surveys, training and instruction in collecting specimens, set- ting up laboratories for final diagnosis of the disease, and making laboratory diagnosis of each of several thousand specimens received each year. Each year, activities of an educational or extension nature by staff members of the Section of Applied Botany and Plant Pathology include talks on plants and vegetation of Illinois, and on diseases of trees, shrubs, and floricultural crops. Ex- aminations are made of numerous plant- ings of ornamental and economic crops in various parts of the state. Numerous pasture lands are examined in co-opera- tion with members of the University of Illinois College of Veterinary Medicine for plants poisonous to livestock. Many plants examined in the field or received throuzh the mail are identified for farm- ers, homeowners, and other interested persons. 160 Ittinois NatrurAL History SurvEY BULLETIN PAST AND PRESENT Early botanical research in Illinois was concerned mainly with field surveys of plants native to the state and with the distribution of these plants in the state. Although botanical research in the state is still concerned with native plants, it is concerned also with the cause and control of diseases affecting ornamental plants— trees, shrubs, and floricultural crops— and losses caused by diseases of economic crops, including cereal, fruit, forage, pas- ture, and vegetable crops. Much of the early work with plants was done by amateur botanists who had very little formal training in botany. Some of these men were physicians who were interested in plants that had medic- inal values. These early botanists were individuals, engaged in various profes- sions or businesses, who were keenly inter- ested in nature, especially in the plant life around them. They usually studied plants in local areas, as their modes of travel were by foot, by horseback, or by car- riage. Their equipment and_ reference works were meager. Their efforts were directed mainly toward the collection and identification of plants. Many of these early botanists were members of the Natural History Society. Some of them became professional bot- anists and were employed by the State Laboratory of Natural History. Inheritors of some of the traditions of these early botanists are the present mem- bers of the Section of Applied Botany and Plant Pathology of the Natural History Survey. Unlike the early botanists, these men have received specialized botanical training in leading colleges and universi- ties of the United States. Their fields of specialization include botany, taxonomy, plant pathology, plant physiology, mycol- ogy, and biochemistry. They are provided with specialized equipment including high-powered com- pound and phase microscopes, high-speed centrifuges, pH meters, fluorescent lamps, spectrophotometer, and Geiger counter, and with excellent library facilities in- cluding numerous books on_ specialized subjects in botany and related fields. They are able to study plants in all parts of the state, as they can rapidly travel] Vol. 27, Art. 2 great distances by automobile, train, air- plane, or helicopter. They study the tax- onomy of plants, as the early botanists did, and in addition the pathology, physi- ology, mycology, and biochemistry of plants, including fungi, and _ especially the fungi that cause diseases of plants. UNSOLVED PROBLEMS The partially solved problems receiv- ing major attention of the Section of Ap- plied Botany and Plant Pathology at the present include the control of glad- iolus corm rots, oak wilt, elm phloem ne- crosis, and Dutch elm disease. Although these diseases have been investigated for several years, continued research is needed to develop more effective treatments for their control. Other unsolved problems include the abnormal growth, wilt, de- cline, or death of trees, floricultural crops, and shrubs used for ornamental, shade, or forest purposes. Some specific unsolved problems are a virus disease complex of gladiolus, a general decline of ash, elm, and oak in localized areas of the state; a rapid decline and death of red pine in localized plantings in north- ern Illinois; wilt, occasionally followed by death, of ash, catalpa, fragrant sumac, Japanese quince, and hard maple; a needle blighting of white pine; diseases of hackberry, Norway spruce, and white pine, with symptoms suggesting virus dis- eases; and wetwood of elm. Although a research program on the control of diseases of fruit, grain, and vegetable crops is conducted by the Agri- cultural Experiment Station at the Uni- versity of Illinois, some of the unsolved or partially solved problems are men- tioned here. Because of the continued ap- pearance of new physiologic races of rust on small grains, it is essential to develop new varieties of grains resistant to these races. Also needed are varieties of small grains resistant to scab and loose smut. Another disease of small grains that needs further study is the virus disease known as yellow dwarf. Corn is affected by stalkrots caused by several fungi; varieties of corn are needed that are resistant to the stalkrot caused by each fungus. Other problems include more effective control for bacterial spot December, 1958 of pepper and for diseases caused by soil- borne microorganisms including bacteria, fungi, and nematodes. If the future can be measured in terms of experience in the past, new diseases and other types of new plant disorders will appear each year to require addi- tional attention of the research personnel of the Section of Applied Botany and Plant Pathology. FUTURE POSSIBILITIES Future possibilities in the botanical survey include further collections of na- tive and naturalized vascular plants to increase the knowledge of the habitats and the range of these species in the state. As plants migrate, slowly under natural conditions but swiftly with the help of man, it is necessary to be on the alert for new additions to the state flora and to give warning if any introductions are of an obnoxious character. The final aim of a floristic study is to produce a manual of the flora of Illinois which will give not only good descriptions of the species but also a discussion of the variations of the species within the state and a discus- sion of their distribution in Illinois. Collections of the nonvascular plants —algae, fungi, and bryophytes—should be expanded. Although a small collec- tion of bryophytes—mosses and_liver- worts—is housed in the herbarium, much collecting remains to be done before the present bryophyte flora and its distribu- tion in the state can be known. A nu- cleus of a phycological collection has been made and should be increased. Only a few of the nonpathogenic fungi are repre- sented in the Natural History Survey col- lections. Collections of slime molds, lichens, and fleshy fungi—mushrooms and bracket fungi—should be started, as these plants are a part of the flora of Illinois and thus a part of the natural resources of the state. Vegetational studies should be contin- ued. Although many of the original prai- rie types of Illinois have been destroyed _ and only remnants remain, these remnants should be described so that future citizens of Illinois will have some botanical knowledge of the prairie types. Hill prai- rie studies should be continued to solve CARTER: APPLIED BOTANY AND PLANT PATHOLOGY 161 some of the problems of succession in this type of prairie and to learn how such prairie recovers from heavy grazing. Ad- ditional study should be made of the vege- tation of the sand areas of the state. An ecological study of the forests in Illinois should be made. The ultimate aim of these studies is to produce a manual of the plant geography of Illinois. Not only should the various vegetations of Illinois be described; remnants of them should be preserved. This is true especially of the prairie types. As we do not know what lies in the future for land use in the locations of the present hill prairies, now one of the least disturbed prairie types in Illinois, several of these beautiful grasslands should be set aside as natural areas by the state or federal government and should be so adminis- tered that picnic parties, hunters, or oth- ers cannot disturb them but that inter- ested persons may view and study them. Although only very small remnants of the flatland and bottomland types of prairie remain, several such remnants should be set aside and allowed to expand so that future generations may have a general idea of the nature of these types of prairie which gave the name “the prairie state” to Illinois. Examples of sand prairies should be preserved. Some of these prai- ries which come under state control should be left as prairies instead of being converted into pine plantations. Aban- doned railroad trackways in sand prairie regions should be permitted to develop as a type of the sand prairie. Other vegeta- tions also should be preserved. The bogs in northeastern Illinois, in Lake County, are valuable from the botanist’s point of view. The few remaining, sizable tam- arack bogs could be easily set aside for the study of bog plants and animals and of succession in the bogs. Future research on plant diseases will continue the advancement of present re- search, and new fields of research will open up. Some of the types of research that appear promising in the control of plant diseases include the use of chemo- therapeutants, antibiotics, and soil fungi- cides. Further research is needed on in- secticides and their indirect role in the control of plant diseases. One instance of this is illustrated in the control of bac- 162 terial scab of gladiolus by use of aldrin to prevent white grub injury to the corms. Chemical compounds obtained from min- eral deposits in the state hold promise for the control of some plant diseases (Schenck & Carter 1954). Research on these compounds through the co-operation of the Geochemical and Coal sections of the Illinois Geological Survey and the Wright Air Development Center of the United States Air Force has been fruitful in the development of fluorine compounds _ with fungicidal properties against certain disease-producing fungi. Research along these lines resulted in publication of six articles on the fungistatic capacities of aromatic fluorine compounds in relation to cloth-rotting fungi (Tehon 1951), 19526, 1954; Tehon & Wolcyrz 1952a, 1952b; Finger, Reed, & Tehon 1955). Research on the physiology of plants and on organisms that produce plant dis- eases will aid materially in the develop- ment of more effective controls for these diseases. One objective of this research is to develop a more realistic approach to the control of diseases through obtaining information on the movement of raw ma- terials, elaborated foods, and chemical I_ttrnois NATuRAL History Survey BULLETIN Vol. 27, Art. 2 compounds introduced into woody plants. The addition of a plant physiologist to our staff would materially increase re- search in this field. In our study of several thousand speci- mens of diseased ornamental plants each year, many unknown fungi are obtained. These fungi need to be identified and those that are found affecting new hosts or that have not been found previously in the state should be added to our myco- logical collection. To adequately handle this work, to make monographic studies of economically important fungi, and to attack new mycological problems as they — appear, a mycologist with special interest in economic fungi would greatly facilitate our research. As we contemplate the future possibili- ties for research by the Section of Ap- plied Botany and Plant Pathology, it is evident that there are unlimited oppor- tunities not only to continue the research now in progress but to expand into new fields of research. This statement applies to the botanical survey, the study of vege- tation, the study of diseases of ornamental plants, and the study of the various kinds of fungi that occur in the state. et aa Mea AE ta es epee be one al SA lt ith, eee, ee ee > ae oe wean Moar OP is Aquatic Biology me research in aquatic biology that was so much a part of the endeavors of the staff of the Illinois State Labora- tory of Natural History and later the Illinois Natural History Survey was in- itiated by Stephen A. Forbes. From the very beginning of his active period in Illinois, Forbes showed great interest in fishes and he began collecting specimens for species records, distributional records, and food habits studies. He wrote ar- ticles on Illinois Crustacea and food of Illinois fishes for the first volume of the Bulletin of the Illinois State Laboratory of Natural History (Forbes 1876, 1878a, 18804, 1880c, 18834, 1883c). In the pe- riod 1876-1888 he collected 1,221 fish of 87 species, 63 genera, and 25 families; these he used to study their diagnostic characteristics, their distribution in the state, and their food habits. Forbes’ inter- est in aquatic biology was broad, and he himself worked on or arranged for others to work on crustaceans, leeches, proto- zoans, rotifers, and aquatic insects, as well as fishes native to I ]linois. BEGINNING OF AQUATIC ECOLOGY Many of the early publications of the Illinois State Laboratory of Natural His- tory dealt with the taxonomy and distri- bution of aquatic animals new to science, or additions to the known distribution of named animals. Forbes was familiar with these subjects and also with the ecology of aquatic organisms at least as early as 1887. In that year his ‘“The Lake as a Microcosm” was first published in the Bulletin of the Peoria Scientific Associa- tion; later it was republished in volume 15 of the Bulletin of the Illinois State Laboratory. In this short but epoch- marking paper, Forbes (1925) described a lake or pond as an environment in which the animals and plants were largely isolated from the surrounding ter- restrial animals and plants ‘but were very much interrelated and _ interdependent GEORGE Wy BENNETTS among themselves; each organism was producing more new individuals than the environment could support, so that many of them served as food for other types of animals, and competition was very keen. Forbes had observed the biological phe- nomena associated with fluctuating water levels—with floods following excessive precipitation and low waters following droughts—and described them as follows: Whenever the waters of the river remain for a long time far beyond their banks, the breed- ing grounds of fishes and other animals are immensely extended, and their food supplies increased to a corresponding degree (Forbes 1925:538). As the waters retire, the lakes are again de- fined; the teeming life which they contain is restricted within daily narrower bounds, and a fearful slaughter follows; the lower and more defenceless animals are penned up more and more closely with their predaceous en- emies, and these thrive for a time to an extraordinary degree (Forbes 1925:539). Forbes recognized that periods of bio- logical expansion and contraction were normal and, without the introduction of abnormal forces, would tend to hold “each species within the limits of a uni- form average number, year after year.” Every organism had its enemies that seemed to be balanced against its repro- ductive potential and, although every species had to “fight its way inch by inch from the egg to maturity,” yet no species Was exterminated. Apparently the Illinois State Fish Commissioners, assigned the duties of protecting the fisheries resources of the state during this period, either had not read Forbes’ ““The Lake as a Microcosm” or did not understand it, because their main activity for the 20 years following 1890 was the rescuing of fishes from the land-locked, drying backwaters of the Illinois and Milississippi rivers and the returning of these fishes to the open wa- ters. Perhaps the Commissioners should not be condemned severely, because their be- liefs and activities were in no way dif- [ 163 J 164 ferent from those of similar bodies in other states throughout the country. They were in tune with the times. In the re- port of the Commissioners to the Gov- ernor of Illinois for the period October 1, 1890, to September 30, 1892 (Bartlett 1893:3), is to be found the following statement: The number of fish left to die in the shal- low waters has been beyond computation, and has seemed to be greater than ever before, from the fact that the attention of the people generally has been called to them and the terrible waste ensuing... . We have been severely criticised because so many fish are allowed to perish, but when the fact is considered that the Mississippi river has a meandering frontage of 450 miles in this State, with bottoms varying in width from a few hundred yards to several miles, and the Illinois and other rivers adding per- haps as much more, it can readily be seen that, if the work were carried on to a suc- cessful completion, it would require hundreds of men and thousands of dollars of ex- pense; in other words, it would be simply impracticable. Fish rescue operations were done with seines dragged through shallow waters by crews of men. The fish were separated from the mud and vegetation and carried by boat to open water, or in tubs to tanks on wagons when overland transportation was necessary. The operations were car- ried on in summer and early fall when both the water and the air were very warm. Today fisheries biologists are well aware of the fact that, even if the fish had been released “alive” in open water, their chance of survival was very low. Few fishes are able to survive even a short exposure to a lukewarm, mud- and-water suspension, such as is created when a seine is dragged through shallow backwaters in August. ‘This statement applies particularly to the game and fine fishes. We now suspect that the phenomenon of fluctuating water levels, which cre- ated a fish rescue problem along the IIli- nois and Mississippi rivers for the Illinois State Fish Commissioners, may have been highly favorable to the well-being of the population of fishes, particularly large- mouth bass, northern pike, walleyes, crappies, and other pan fishes. A com- bination of natural predation (largely by fish-eating birds) and water level fluc- tuations prevented excessive competition Intinois NarurAL History SurvEY BULLETIN among the coexisting species and allowed for excellent survival of game fish. The Vol. 27, Art. 29 report of the Fish Commissioners (Bart- — lett 1893:4) for the 2-year period ending September 30, 1892, contains the follow- — ing statement: In the Quincy Bay [of the Mississippi River], this season, the number of black bass has been unprecedented, and a fair estimate of the number taken with hook and line would place it in the hundreds of thousands. Most of them were too small to use on the table, yet were as voracious as larger ones and fell an easy prey to the angler, whether he of the rod and reel or the small boy with a willow switch and a tow line, all caught bass. One man, who called himself a sports- man, boasted of having caught 800 of them in one day with hook and line, all too small to eat, but he carried them away and threw them on the ash heap. From my office win- dow I saw 225 taken by two little boys in one day, all of them wasted. The production of a dominant brood of bass (undoubtedly largemouth) such as this might be expected to follow a pe- riod of very low water in the late sum- mer and fall and a period of moderately high water during the bass spawning sea- son the following June. The theory of the benefits of fluctuat- ing water levels is further substantiated by a published record of the catch of four commercial fishing firms operating in the Illinois River near Havana between July 1 and December 1 (5 months) in 1895 (Roe & Schmidt 1897). Their catch was 358,843 pounds, mostly of carp and buf- falo, which made up 85.7 per cent of the total. An unusual part of the catch was the proportion of “bass” (undoubtedly largemouth), 7,852 pounds, and walleye : and “pike” (northern), each 200 pounds. The last two species are seldom taken in the Illinois River today. The catch of bass (7,852 pounds) was larger than the catch of crappies (7,405 pounds). Crappies are easily caught in hoop and fyke nets or seines; bass do not enter hoop and fyke nets readily and when surrounded with a seine they show considerable aptitude for jumping over. Inasmuch as more pounds of bass than of crappies were caught, prob- ably many more pounds of bass were available. Today, with water levels of bottom- land lakes in the Havana region much more stabilized, it would be an impossi- December, 1958 ble task to catch 7,000 pounds of bass with commercial fishing gear. This im- portant game species is very much less abundant now than it was when the river was free to spread over its wide flood plain. FIRST FIELD LABORATORY Forbes was much interested in the Illi- nois River and in 1894 he established a biological station on its shores (Forbes 1895a:39) “for the continuous investiga- tion of the aquatic life of the Illinois river and its dependent waters, near Havana.” That Forbes (1895a:46-7) had great breadth of vision in biological research is shown by his description of the objectives of the laboratory: The general objects of our Station are to provide additional facilities and resources for the natural history survey of the State, now being carried on, under legislative authoriza- tion, by the State Laboratory of Natural His- tory; to contribute largely to a thoroughgoing scientific knowledge of the whole system of life existing in the waters of this State, with a view to economic as well as educational applications, and especially with reference to the improvement of fish culture and to the prevention of a progressive pollution of our streams and lakes; to occupy a rich and promising field of original biological investi- gation hitherto largely overlooked or neglect- ed, not only in America, but throughout the world; and to increase the resources of the zoological and botanical departments of the University by providing means and facilities for special lines of both graduate and under- graduate work and study for those taking major courses in these departments. The Station differs from most of the small number of similar stations thus far estab- lished in this country from the fact that its main object is investigation instead of in- struction, the latter being a secondary, and at present an incidental object only. It has for its field the entire system of life in the Illinois river and connected lakes and other adjacent waters, and it is my intention to extend the work as rapidly as possible to the Mississippi river system, thus making a beginning on a comprehensive and_ very thoroughgoing work in the general field of the aquatic life of the Mississippi Valley, in all its relations, scientific and economic. The special subject which I have fixed upon as the point of direction towards which all our studies shall tend is the effect on the aquatic plant and animal life of a _ region produced by the periodical overflow and gradual recession of the waters of great rivers, phenomena of which the Illinois and Mississippi rivers afford excellent and strong- ly marked examples. BeNNeETY: AQuatic BIoLocy 165 Forbes (1895a:47) believed that the natural sciences should be studied out of doors and that colleges and universities of his day were not doing well by their students in botany and zoology when they confined them to laboratory studies: Not many years ago, biological instruction in American colleges was mostly derived from books. Of late, it has been largely ob- tained from laboratories instead, but several years’ experience of the output of the zodlogi- cal college laboratory has convinced me that the mere book-worm is hardly narrower and more mechanical than the mere laboratory grub. Both have suffered, and almost equally, from a lack of opportunity to study nature alive. One knows about as much as the other of the real aspect of living nature and of the ways in which living things limit and de- termine each others’ activities and characters, or in which all are determined by the in- organic environment. It is possible that Forbes’ feeling on this point of training may have influenced the University of Illinois to require field courses at a_ biological station before granting a graduate degree in zoology. Havana was selected as the location for the Illinois Biological Station because of its several advantages: Forbes liked the bluffs along the eastern shore of the IlIli- nois River because at their bases they furnished a clean, hard sand beach suit- able to work from and ideal for camping. Moreover, along these bluffs was an abundance of pure, cold spring water. The laboratory consisted of “three well-placed rooms” in the town itself and a “cabin boat” on the Illinois River. The office and laboratory rooms were sup- plied with running water and electric light, and liberally provided with the usual equip- ment of a biological laboratory, consisting of compound and dissecting microscopes (Rei- chert and Zeiss), microtomes, biological re- agents to the number of one hundred bottles, water and [paraffin] baths, laboratory glass- ware, tanks for alcohol, a coal stove, a kero- sene stove, laboratory tables for five assist- ants, and a working library of about one hundred and twenty volumes’ (Forbes 1895a:48). The cabin boat was stationed on Quiver Lake north of Havana, about 2.5 miles from town. The boat contained a well- furnished kitchen and sleeping quarters for four men. Most of the rest of the space was taken up by equipment, includ- ing limnological apparatus, seines, collect- ing nets, microscopes, and a small library. 166 I_tinois NATURAL History SuRVEY BULLETIN The original staff of the station, in 1894, consisted of Frank Smith, who was directly in charge and whose principal in- terest was aquatic worms; Charles A. Hart, entomologist and curator of col- lections for the State Laboratory; Adolph Hempel, who worked on protozoans and rotifers; and Mrs. Dora Smith, who served as microtechnician and was in charge of the rooms in Havana. Miles Newberry, who lived in Havana, had charge of the cabin boat and acted as a general field assistant. Others who were present at some time during the first year of operation were Ernest Forbes, for 6 weeks of general collecting, Professor Thomas J. Burrill, a Mr. Clinton, a Mr. Yeakel, and a Miss Ayers, all of the Uni- versity of Illinois Botany Department, who were collecting aquatic plants; a Professor Palmer, who was making chem- ical analyses of the water; Assistant Pro- fessor Henry E. Summers of the Univer- sity Physiology Department, who photo- graphed the region; and the staff artist, Miss Lydia M. Hart. Professor Forbes exercised general supervision over the sta- tion work, planning and following its op- eration. FISHES AND PLANKTON Within a year or so aquatic investiga- tions were stepped up through increased use of the laboratory and cabin boat at Havana. At the beginning of this cen- tury Frank Smith (1901:567) stated in Science that the ichthyological survey of Illinois had received much attention dur- ing the previous 2 years and that a com- prehensive report was soon to be pub- lished. He also stated that Dr. C. A. Kofoid had been studying the plankton of the Illinois River for the previous 5 years. This short statement in Science announced the progress being made on two of the important contemporary con- tributions to aquatic biology, namely Forbes & Richardson’s The Fishes of Illinois (1908) and Kofoid’s studies on the plankton of the Illinois River. Shortly after, in an essay dealing with “statistical ecology,” Forbes (1907a) pre- sented a method for showing relation- ships between individual species of fishes and preferences of certain kinds of fishes Vol. 27, Art. 2 with respect to features of the physical environment. The validity of this method depended upon the numbers of collections that were available for study. Where sufficiently large numbers of collections could be mustered, Forbes compared ob- served relationships with expected rela- tionships and obtained a coefficient of as- sociation by dividing the former by the latter. A hypothetical example is given below: Given species 4 and species B inhabit- ing waters in the same general land area: In 1,000 collections, species 4 occurred 159 times and species B 85 times. Thus, the probability that they would occur to- gether in any single collection was 159/1,000 85/1,000 or 13,515 times in a million or 13.5 times in 1,000, and the probable number of these double oc- currences in the 1,000 collections was 13.5/1,000 > 1,000/1 or 13.5 times: However, in the 1,000 collections, spe- cies 4 and species B were found together in 40; thus, the coefficient of association for species 4 and B was 40/13.5 or 2.96: they were found together about three times as often as was to be expected. This same type of reasoning was ap- plied to show relationships between indi- vidual species and the physical environ- ment: stream, lake, pond, marsh; size of water area and water movement; bottom of mud, sand, gravel, or rock. These co- efficients of association are found fre- quently in Forbes & Richardson’s The Fishes of Illinois. Unfortunately about half the collections referred to in this pub- lication were made without notes on wa- ter current and bottom materials, so that this method of showing association could be applied only to stream, lake, pond, or marsh, or to sectional distribution in the state. Thus, when Forbes & Richardson (1908:195) stated that the frequency ratios for a fish were ‘3.19 for the smaller rivers, 2.06 for creeks, and .58 for the largest streams,” they meant that these fish exceeded expectancy in “smaller riv- ers” and “creeks” by about 3 and 2 times, respectively, and were considerably below expectancy in “the largest streams.” A coefficient of association of 1 indicated correspondence with expectancy; a co- efficient below 1 indicated a negative re- lationship. December, 1958 This method of showing ecological re- lationships between species and ranges, species and local habitats, or between spe- cies themselves, allowed the use of num- bers to show the degree of the relation- ship or lack of it. Its shortcoming was that it made no distinction between col- lections containing one fish of a species under consideration and those containing several hundreds or thousands. THE FISHES OF ILLINOIS The first edition of The Fishes of Illi- nois was published by the State of Illinois in 1908; a second edition was published in 1920. Collections and observations for this work had been started in 1876 by Forbes and had been expanded through the help of many assistants working at rather irregular intervals until 1903. Field work on fishes became nearly con- tinuous for a few years after establish- ment of the Illinois Biological Station at Havana in 1894. Special recognition was given to Wallace Craig, who collected during the winter and spring seasons of 1898 and 1899, to H. A. Surface, who collected during 1899, and to Thomas Large, who made extensive wagon trips, the most important of them in 1899, to collect fishes from streams in many parts of the state. Recognition was given also to unnamed high school teachers who col- lected fishes under specific instructions. Collections of fishes studied by Forbes and Richardson were taken from many sources: catches made by collecting par- ties with seines of various size and mesh (including minnow seines and_ bag seines), trammel nets, set nets (both fyke and hoop) ; catches made by commercial fishermen; and selections from fishes on display in fish markets. More than 200,- 000 specimens representing 150 species were collected from more than 450 loca- tions in the state. The Fishes of Illinois was published in two parts, one of which was an atlas. The larger or first part contained a sec- tion on “The Topography and Hydrog- raphy of Illinois’ written by Professor Charles W. Rolfe, at that time head of the Geology Department of the Univer- sity, a section entitled “On the General and Interior Distribution of Illinois BENNETT: AQUATIC BIoLoGy 167 Fishes,” a section on “The Fisheries of Illinois,” and one on the individual spe- cies of fishes found in the state. This last section made up by far the largest num- ber of pages and included keys for the identification of fishes and a glossary of technical terms. For each species of fish were given the scientific name, common name or names, synonomy of scientific names (where such existed), and a de- tailed description of the fish. The de- scription was followed by a statement of the fish’s distribution within and without the state, a statement on average and maximum lengths and weights, and infor- mation on habitat preferences, food pref- erences, and other phases of biology. For most species, information was given on how the fish might be caught and its value (if any) as food. Many species were illustrated by black and white photo- graphs or by colored plates painted by Mrs. Lydia M. (Hart) Green and Miss Charlotte M. Pinkerton. These colored plates were so fine that for nearly a half century none published elsewhere was their equal. The second part, the atlas, contained maps of the 10 stream systems of the state. These maps showed the glacial ge- ology of Illinois, localities from which collections were made, and interior dis- tribution of 98 of the most important fishes. As a state publication on fresh-water fishes, The Fishes of Illinois remained unique for a period of more than 40 years. ILLINOIS RIVER PLANKTON Kofoid’s studies of the plankton of the Illinois River appeared as five articles in volumes 5, 6, and 8 of the Bulletin of the State Laboratory of Natural History. Altogether Kofoid published nearly 1,000 printed pages on the plankton of the IIli- nois River. From 1895 to 1900 Kofoid was su- perintendent of the biological station at Havana. In 1900 he went to the Uni- versity of California at Berkeley. At the time he left Illinois for California and a new position, he had published only three short papers on plankton, one dealing with methods and apparatus, one with a 168 Ittinois NarurAL History SURVEY BULLETIN Vol. 27, Art. 2 Two members of the staff of the Illinois State Laboratory of Natural History making obser- vations on the breeding habits of fish near Havana, 1910 or 1911. The box at the stern of the boat was used by observers in watching the movements of fish and in searching for fish nests and fry. new species, and one with a new genus of plankton (Kofoid 1897, 1898, 1899). Two longer papers on plankton (Kofoid 1903, 1908), one on quantitative inves- tigations and the other on constituent or- ganisms and their seasonal distribution, he wrote in California. Kofoid remained on the staff at Berkeley until his retire- ment in 1936. BOTTOM FAUNA R. E. Richardson’s classic studies of the bottom fauna of the Illinois River covered a period that coincided with se- vere changes in the biology of the river (Forbes & Richardson 1913, 1919; Rich- ardson 1921, 1925a, 1925b, 1928). Be- fore 1900 the Illinois was a reasonably clean river receiving very limited organic pollution from a small number of towns along its banks. By 1900 Chicago had become an important trading center and was growing rapidly. In order to get rid of the sewage and the organic waste from a number of meat packing plants of Chi- cago, a diversion channel was opened be- tween Lake Michigan and the Des Plaines River, one of the headwater streams which united with the Kankakee to form the Illinois. Forbes and Rich- ardson had collected bottom fauna in the Illinois prior to 1900, and Richardson had continued to do so after the diver- sion of Lake Michigan water had begun. At first the organic pollutants created a nuisance only in the upper part of the river, at Morris, Marseilles, and Starved Rock. Richardson studied the bottom fauna throughout the length of the upper part of the river in 1909, 1910, and 1911 and found that the river was nearly nor- mal at Chillicothe and Hennepin. Above these towns it became progressively more polluted. During the period 1900-1908 the or- ganic pollutants acted as fertilizer, and the annual fish yield of the lower part of the Illinois increased from 11.5 million to 24 million pounds. Gradually, after December, 1958 1908, organic waste from Chicago in- creased until the volume approached the capacity of the river to oxidize it. Diver- sion was increased, and the fish yield dropped; a peak diversion occurred in 1927 with a flow of 10,245 cubic feet per second (Mulvihill & Cornish 1930:57). The period of maximum pollution oc- curred between 1915 and 1920. From his studies of bottom fauna during this time, Richardson calculated a reduction in the total weight of bottom organisms in the reach from Chillicothe to La Grange of 34.5 million pounds, representing a po- tential loss of 7 million pounds of fish. By 1921 the fish yield of the river had hit an all-time low of 4 million pounds, partly from pollution and partly from ex- tensive bottomland lake drainage. After 1922 there was some reduction of the raw sewage going into the Illinois River, and from 1924 to 1930 the yield of commer- cial fish varied around 10 million pounds per year. Between 1913 and 1928, Richardson (with some assistance from Forbes on two of the early papers) published six articles in the Bulletin series. Because of the op- portune timing of his studies in relation to the pollution of the Illinois, Richard- son was able to set up a classification of seven degrees of pollution based on the presence of certain groups of aquatic or- ganisms. These groups were often better indicators of the degree of pollution than were oxygen analyses, because the animal associations were sensitive to small in- creases in pollution, or to fluctuations in pollution that might be missed unless oxygen analyses were made continuously. NEW LINES OF RESEARCH During the second decade of the twen- tieth century, biologists became interested in measuring the effects of physical and chemical changes in the aquatic environ- ment upon fish, and in the responses of the fish to these changes. From 1914 to 1925, members of the staff working in aquatic biology published papers on the suitability of bodies of water for fishes; the poisoning of fishes by illuminating gas wastes; the reaction of fishes to carbon di- oxide and carbon monoxide; a collecting bottle for quantitative determination of BENNETT: AQuatic BIoLoGy 169 dissolved gases; methods of measuring the dangers of pollution to fisheries; and ob- servations on the oxygen requirements of fishes in the Illinois River. These publi- cations were the work of Victor E. Shel- ford (1917, 1918a, 19185), Morris M. Wells (1918), Edwin B. Powers (1918), and David H. ‘Thompson (1925). They represent a new approach to fisheries studies, e.g., the use of labora- tory studies to explain and expand the knowledge of the relationships of fishes and other aquatic organisms to their en- vironments. In the early 1920’s aquatic investiga- tions were continued on the Illinois River, where the Natural History Survey main- tained a houseboat laboratory and attend- ing boats and equipment. At this time studies were begun on the lakes of north- eastern Illinois, studies that included the taking of quantitative plankton and _ bot- tom samples and collections of fishes and higher aquatic plants. In 1923, an inves- tigation was begun also on the Rock River (Forbes 1928). Surveys on the Illinois River, made in co-operation with the Illinois Water Sur- vey in 1923 and 1924, showed that the normal life of the river had been de- stroyed by pollution as far down as Peoria Lake. By 1927 the staff had published in the Bulletin 20 articles, comprising 1,856 printed pages, on Illinois River biology. These articles apparently had had a pro- found effect on aquatic biologists in many parts of the United States; other states were engaged in making their own lake and stream surveys, for the most part not so comprehensive as those of the Illinois River, but adequate to give some informa- tion on physical and chemical conditions and rough measurements of the fish food resources, plus inventories of the kinds and relative abundance of fishes present. At this time (1927) the Natural His- tory Survey had expanded its own stream survey program to include, besides the Rock River, the Hennepin Canal, the Sangamon and Kaskaskia rivers, and the streams of Champaign County (Forbes 1928). The Rock River investigation was operated from 1923 to 1927 with David H. Thompson in charge of field collecting and R. E. Richardson in charge 170 ILLINoIs NATURAL History SurRvEY BULLETIN of the analysis of data at Urbana. Thompson and three or four other men, working steadily each year through spring, summer, and fall, collected and shipped to Urbana about 90,000 fishes of 90 species, 2,400 fish stomachs, 15,000 river mussels belonging to 40 species, 820 collections of small invertebrates, and 500 collections of plankton and algae. Samuel Eddy (1927, 1931, 1932) worked on the plankton of Lake Michi- gan and the Sangamon River and on plankton collections from some sinkhole ponds in southern Illinois. EARLY MANAGEMENT ATTEMPTS Many of the early activities in the man- agement of aquatic resources of the United States were based on premises which later research proved to be inac- curate or erroneous. These included such measures as stocking and the protection of fish from human exploitation through re- strictions in the form of fishing seasons, length limits, and creel limits. Toward the end of the last century, James Nevin (1898:18), speaking before the American Fisheries Society, made the following statement: Personally I have been on the various spawning grounds of the whole chain of Great Lakes from the Gulf of St. Lawrence to Lake Superior during the spawning seasons; and | have many times watched the salmon trout, white fish and wall-eyed pike spawn in their natural way; and I am convinced that only a very small percentage of the eggs so de- posited are fertilized. This statement represented the attitude of the hatchery supervisors and most ad- ministrative personnel connected with federal and state agencies dealing with fisheries resources. As the spawning grounds of most fishes of the Great Lakes remain relatively unexplored even today, it is doubtful if Nevin was very familiar with them. Ideas having no scientific basis often become widely accepted. For example, al- most everyone has heard that one should wet his hands before handling a fish if he wants it to remain alive after release. Apparently this idea originated with G. H. Thomson, Superintendent of the Estes Park Fish Hatchery, Colorado. Vol. 27, Art. 2 Thomson had cards printed with the title, ““A Plea for the Fish.” The cards stated: When removing an undersized trout from your hook, always moisten your hands before grasping the fish; otherwise the dry hand will remove the slime from the back of the trout, when it is only a question of time until fungus sets in and the fish will die. Thomson distributed these cards to residents of all states and of many foreign countries. In 1912 he reported that at the September 21—24, 1908, meeting of the American Fisheries Society in Wash- ington, D. C., the Society “recommended that the various state commissions educate the people by every means in their power to follow the directions given about wet- ting the hands” (Thomson 1913:171). He reported also that his program was endorsed by 28 fish and game commis- sioners throughout the United States. His idea was so widely disseminated that al- most everyone has heard of it; yet there is no evidence that any attempt was made to test it through scientific experimentation. In spite of continued emphasis on arti- ficial propagation, new techniques were gradually discovered and put into use by researchers in the fisheries field, and these laid the foundation for modern thought in management. Borodin (1924) and Barney (1924) called attention to the value of using growth rings on scales and otoliths for determining the age of fishes; Wiebe (1929) proposed the use of fertilizers to increase plankton produc- tion; Surber (1931) discussed the use of sodium arsenite in the control of aquatic vegetation; Burr (1931) used electrical equipment to stun fish; Markus (1932) investigated the relationship between water temperatures and food digestion in largemouth bass; through tagging and re- covery, Thompson (1933a) studied mi- grations of stream fishes. These and other findings laid the groundwork for modern attack on the problems of fish management. MODERN MANAGEMENT The modern concept and use of the term “fish management” first appeared about 30 years ago. It was suggested December, 1958 (if not named) by E. A. Birge in writing about fish and their food. Birge (1929:194) stated: Good fishing for sport calls for the con- tinued presence in a lake of a relatively few large individuals of the desired _ species, which are to be caught singly. They must be larger than the average adult. They are not caught primarily for food but for sport and as a basis for stories. A dozen half- pound bass are by no means an equivalent to one three-pounder from this point of view. But these large individuals are few in num- ber: they are old and have come to full size very slowly. It is easy to catch them and very hard to replace them in the presence of the vigorous competition for food that goes on in a lake. And as yet little thought and less study have been given to the needs of this specific form of conservation of fish resources. (Italics mine.) This statement implies a concept of management for sport fishing. When Carl L. Hubbs described the organization of the Institute for Fisheries Research (Hubbs 1930), fisheries re- searchers in Michigan were working on a state-wide creel census, lake and stream surveys, stream improvement, nursery waters, fish migration, predators of fish, fish diseases, and fish growth. At about the same time, fisheries re- search at the Illinois Natural History Survey (Wickliff 1933) included studies of fish migration through tagging of fish, ages and growth rates of important fishes, general quantitative determinations of plankton and bottom organisms, a com- parison of fish population densities by means of standardized fishing methods, and the determination of the fish popu- lation of a lake by capture, fin marking, and recapture of adult fish. The point at which fish management emerged as a more or less discrete dis- cipline is not easily established. If fish management is assumed to be the art of producing sustained annual crops of wild fish for recreational use (modified from Leopold 1933), agreement as to the time management began is difficult to reach. Modern management could hardly have made a beginning until biologists had discovered enough basic information about fishes to be able to discredit the unfounded but strongly held theories relative to the values of stocking, closed seasons, length limits, and creel limits. This basic information came from many BENNETT: AQUATIC BIOLOGY 171 sources and was available before 1940. In Ohio, Langlois (1937) was convinced that the closed season was worthless for increasing the numbers of bass. In Mich- igan, Eschmeyer (1938) had _ poisoned the entire fish populations of several small lakes in which the fishing was poor and had discovered an ‘‘overabundance of fish” instead of a scarcity. Also in Mich- igan, Carbine (1939) had _ investigated the spawning and hatching of nest-build- ing centrarchids in Deep Lake and had discovered that many more young were produced than the lake could support. In Illinois, David H. Thompson had _ fol- lowed dominant broods of crappies in Lake Senachwine for 4 years (1933- 1936) and had come to the conclusion that, while sizes and numbers of fish varied, the total weight of the popula- tion remained fairly constant. Also in Illinois, Thompson & Bennett (1939c) had demonstrated relationships between length of food chains and poundages of fish supported by ponds. In Alabama, Swingle & Smith (1939) had demon- strated the capacity of fish populations to expand or contract in relation to the capacity of the habitat to support them. These researches on the dynamics of fish populations formed the bases for modern fish management. Yet old ideas were difficult to uproot. Clarence R. Lucas (1939) of the U. S. Bureau of Fisheries published a paper titled ““Game Fish Management,” in which he listed what he termed the “operative” tech- niques of fish management: (1) regula- tion—closed seasons, bag limits; (2) fish culture—rearing of game fishes for stock- ing; (3) distribution—transportation and liberation of hatchery-reared fish; (4) stream and lake improvement; and (5) predator control—the removal of preda- tory fishes or of fishes that otherwise interfere with the production of the game fish crop. This paper reflected exactly the old conception of operation, but under a new name. Thompson’s ideas on fish management were summarized in his contribution to A Symposium on Hydrobiology. In a sec- tion titled ““The Fish Production of In- land Streams and Lakes” ‘Thompson (1941) stated that production and yield were synonymous—both represented the 172 crop that was harvested. The total amount of fish in a lake or stream at any given time was the standing crop; when the standing crop reached “saturation” it represented the carrying capacity of the lake or stream. Thompson believed that the food resources and the carrying ca- pacity of a body of water remained fairly constant but that the number of fish could vary widely. He reasoned that, if the weight of fish remained constant, then the removal of some fish would furnish more food per individual for those re- maining, and the growth rate would in- crease; if more fish were planted, less food would be available per individual, and the growth rate would decrease. ‘To further this thesis, he was able to demon- strate from his own laboratory experi- ments that at a water temperature of 70 degrees F. a 10-inch bass required as food an amount of minnows equal to three- fourths of 1 per cent of its body weight per day in order to maintain a constant weight; and that, at an optimum feeding rate, 2.5 pounds of minnows were re- quired to produce 1 pound of bass. Complete censuses of nine Illinois lakes subject to floods and indiscriminate stock- ing showed that, although 46 different species were present, only 10 species of fish comprised more than 1 per cent each of the total weight of all fish. The rough fish listed were redmouth buffalo, mon- grel buffalo, and carp; forage fish were gizzard shad and golden shiner; catfish included only the black bullhead; the pan or fine fish were bluegill, white crappie, and black crappie; and the only game fish was the largemouth bass. These species must be considered as showing superior adjustment to the pond habitat in Illinois. Thompson had observed cycles in fish that were the result of interspecific and intraspecific competition. The ‘“‘fine’’ fish in Lake Senachwine (Illinois) amounted to about 50 to 55 pounds per acre, regard- less of the number of fish or the area of the lake. In some years there were 10 times as many fish as in other years, and the individual fish averaged one-tenth the weight of the individual fish of other years. Large broods of crappies were pro- duced at intervals of about 4 years, and during interim seasons they controlled the I~ttinois NaturAL History Survey BULLETIN Vol. 27, Art. 2 survival of their own young and the young of other species. Thompson attempted to construct a theoretical maximum cropping rate for any water area as a percentage of its carrying capacity. He believed that the cropping rate was related to latitude (length of growing season). He estimat- ed annual cropping rates for Vilas Coun- ty and Madison, Wisconsin; Urbana and Cairo, Illinois; Memphis, ‘Tennessee; Jackson, Mississippi; and New Orleans, Louisiana. He assumed that in northern Wisconsin about 21 per cent of the carry- ing capacity could be replaced each year; in New Orleans the replacement could be as much as 118 per cent; other loca- tions fell between these extremes. Thompson also presented the idea that fish predators were probably beneficial, al- though he gave no data to back this assumption. THE LAST TWENTY YEARS With the death of Robert E. Richard- son in 1935, the aquatic biology staff of the Illinois Natural History Survey was reduced to Thompson and one full-time field assistant; however, several graduate students were working under Thomp- son’s direction. At that time, Thompson was interested in beginning some pond management investigations. As a result of a policy of expansion for the Section of Aquatic Biology, I was employed on January 1, 1938, to work with Thompson on ponds. To gather experience in a new censusing technique that involved poisoning fish with rotenone, a technique developed by R. W. Eschmeyer in Mich- igan, Thompson and I made a trip to Ann Arbor, where Eschmeyer was censusing several small Michigan lakes. We helped in one of the censusing operations and were served some of the poisoned fish at the home of Dr. Carl L. Hubbs. Returning to Illinois, we (with the help of Donald F. Hansen) began cen- susing ponds, one of the first of which was Homewood Lake, a 2.8-acre pond on the property of the Homewood Fishing Club on the outskirts of Decatur, Illinois. From the standpoint of public relations, the operation was a huge success. The pond contained mostly carp, buffalo, giz- ——— ss December, 1958 zard shad, and stunted bluegills; all day, local sportsmen slipped through the un- derbrush to spy on the “fish killers,” but, seeing few, or no, dead useful hook-and- line fish, they stayed to help us collect the outsized carp and buffalo. Through the able assistance of Sam A. Parr, at that time Investigator for the Department of Conservation for Macon County, we were able to census 22 arti- ficial lakes and ponds in central and southern Illinois. One of these ponds was Fork Lake, owned by Paul S. Smith (formerly Chief Inspector with the De- partment of Conservation), who gave us carte blanche use of the pond. ‘These censuses, and the studies of the fish popu- lations that replaced those poisoned in these ponds, led to the publication of three reports on lake management (Thompson & Bennett 1939a, 1939b, and Bennett, Thompson, & Parr 1940) and two articles of the Bulletin, ‘Management of Small Artificial Lakes” (Bennett 1943) and “The Bass-Bluegill Combination in a Small Artificial Lake” (Bennett 1948). Censuses of the ponds, most of which were poor fishing waters, brought out the fact that overpopulation and stunting and/or large numbers of fish of undesir- able species, rather than a lack of fish, were the causes of poor fishing. In fact, one of the poorest ponds for fishing was found to contain 1,145 pounds of fish per acre. At Fork Lake (‘The Bass-Bluegill Combination in a Small Artificial Lake’’), we attempted to crop heavily the large- mouth bass and bluegills in this 1.4-acre pond; we used six fyke nets of 1-inch- mesh, set with leads to completely block off the pond into sections. When these nets were fished for 10 days each month from March to November of each year for 3 years, we discovered that we could not crop the bass because they refused to enter the nets, and the constant cropping of bluegills contributed to the well-being of both species. This discovery led to the belief that anglers had nothing to fear from commercial fishing operations. In July of 1938 Hansen was given charge of the scale collections for study- ing age and growth of fishes and the task of investigating the fish populations of water supply reservoirs where fishing was an important secondary function to water Bennetr: AQUATIC BIOLOGY 173 supply. At that time he was operating fyke nets at Lake Decatur and in other waters in order to gather material for a life history study of the white crappie (Hansen 1951). In the late 1930’s and the early 1940's federal agencies were engaged in con- struction projects under various work programs. ‘The Natural History Survey was to benefit from these programs through the construction of a laboratory located on the Chautauqua National Wildlife Refuge, near Havana, and a laboratory and artificial lake in Fox Ridge State Park, near Charleston. The Havana laboratory, completed in early 1940, became the headquarters for water- fowl and fishery research on the Illinois and Mississippi rivers. ‘The laboratory and lake in Fox Ridge State Park were completed in 1941 and became a center for studies on largemouth bass management. About the same time the U. S. Forest Service constructed two lakes in the Shawnee National Forest in the southern part of Illinois. These were Pounds Hol- low Lake, near Gibsonia, and Lake Glen- dale, near Dixon Springs; the latter has been used by the Natural History Sur- vey as a study area since it was first stocked in 1940. Lake Glendale is located in a region of low soil fertility and is fairly typical of impoundments in forested lands. Hansen has found that the lake produces excessive populations of both bass and bluegills, and that fishing may be improved at intervals by the removal of part of the population of both of these species. In 1942 Thompson and Hansen made a fish survey of the Illinois River from Channahon to the river mouth at Graf- ton. About 34,000 fish were studied, most of which were caught in hoop or fyke nets. Many of the carp in the upper part of the river (particularly at all sta- tions above Henry) showed the knothead abnormality which was an indication of gross pollution. At Channahon 94.8 per cent of the catch was composed of “rough” fish, most of them carp or gold- fish. In contrast, at the Creve Coeur station below Peoria, 88.4 per cent of the fish taken were “‘fine” fish (most of them white crappies or black crappies) and only 6.0 per cent were “rough’’ fish. 174 Intinois NATURAL History SuRVEY BULLETIN In December, 1943, conservation representa- tives from the states of Illinois, Iowa, Mis- souri, Minnesota, and Wisconsin, from the United States Fish and Wildlife Service, and from other interested agencies met at Dubuque, lowa, and formed the Upper Mississippi River Conservation Committee (Smith 1949). This group was organized for the purpose of spon- soring studies of the fishery and wildlife re- sources of the Mississippi River from Ca- ruthersville, Missouri, to Hastings, Minnesota. The studies were designed to serve as a basis for making scientifically sound recommenda- tions for the management of these resources (Barnickol & Starrett 1951:267). Field operations in the Missouri-Illi- nois section were begun in March, 1944, with the Conservation Commission of Missouri, the Illinois Department of Con- servation, and the Illinois Natural His- tory Survey participating. A crew con- sisting of four men, working from the Natural History Survey’s laboratory boat Anax, operated test nets and other types of fishing gear at 19 stations between Caruthersville, Missouri, and Warsaw, Illinois. two years later, in 1946, field operations were resumed in the Iowa-lIlli- nois part of the river with the Iowa Con- servation Commission and the two IlIli- nois agencies co-operating. The survey in 1944 was begun with Thompson in charge of the laboratory boat and Paul G. Barnickol as the chief fisheries investi- gator for Missouri. Thompson resigned from the Natural History Survey to go with the Forest Preserve District of Cook County, and in May, 1945, Barnickol was employed to replace him. Barnickol was in charge of the crew that covered the upper part of the river from Burling- ton to Dubuque in 1946. In May, 1948, Barnickol was recalled to Missouri to be- come Head of Fisheries Research for the Conservation Commission. At that time data from 2 years of field work on the Mississippi River were only partly analyzed. On July 1, 1948, William C. Starrett began employment by the Natural His- tory Survey for the difficult task of work- ing over Mississippi River fishery data collected by others. In this he had the co-operation of Barnickol; their combined efforts resulted in publication of two articles of the Natural History Survey Bulletin: “Commercial and Sport Fishes of the Mississippi River Between Caruth- Vol. 27, Art. 2 ersville, Missouri, and Dubuque, Iowa” (Barnickol & Starrett 1951) and “Eff- ciency and Selectivity of Commercial Fish- ing Devices Used on the Miaississippi River” (Starrett & Barnickol 1955). The first of these articles listed the fishes caught in the Mississippi River, their distribution, size range, growth rates, and other information on their biology. A total of 26,037 fish weighing 28,294 pounds were taken in 1944 and 1946. The second article presented a statistical study of the efficiency and selectivity of various types of gear used in the Mis- sissipp1 River survey. The study was made for the purpose of furnishing infor- mation to those assigned the task of man- aging the river’s commercial fishery. It included a consideration of seines, tram- mel nets, basket traps, wing nets, hoop nets, trap nets, and trot lines, the kinds of fish most commonly captured or trapped, the sizes of fish taken with various mesh sizes, and the comparative efficiency of several types of gear. One of the interesting findings to come out of the Mississippi River survey was the collection of post-larval paddlefish, Polyodon spathula (Wal.), by Thomp- son and Barnickol. While minnow sein- ing off a sand bar in the Mississippi near Cape Girardeau, Missouri, on May 29, 1944, the Thompson and Barnickol party took four paddlefish ranging in length from 17 to 26 mm. Other than the col- lection of seven paddlefish larvae (17—20 mm.) taken by Thompson in 1933 (Thompson 1933b), these are the only young paddlefish of less than 35 mm. in length known to have been collected. These post-larval paddlefish and other paddlefish material were studied by R. Weldon Larimore (1949, 1950), who de- scribed the changes in the cranial nerves of the paddlefish accompanying develop- ment of the rostrum and gametogenesis of Polyodon and its relationship to prac- tical regulation of the paddlefish fishery. In 1948 Larimore was made a per- manent member of the Aquatic Biology staff. He had already nearly completed a study on the life history and ecology of the warmouth, Chaenobryttus gulosus (Cuvier), a fish that was being consid- ered as a possible companion species for largemouth bass in ponds. This study of December, 1958 the warmouth was later published as an article of the Natural History Survey Bulletin (Larimore 1957). During the summer of 1950 Larimore, with the help of Leonard Durham and others, began an intensive investigation of the fishes in Jordan Creek, a small spring-fed, upland stream in Vermilion County. This project marked the _ be- ginning of upland stream investigations as a continuous program of the Section of Aquatic Biology. Through the use of the electric seine and other special equip- ment developed for stream work, it has been possible to make both intensive and extensive studies on the ecology of stream fishes in the central Illinois region (Lari- more, Pickering, & Durham 1952). The smallmouth bass, Micropterus dolomieui Lacépéde, was found to be the most im- portant anglers’ fish in these streams. The fry of this bass were particularly vulnerable to floods on streams when the floods were accompanied by — sudden changes in water temperatures. The adult BENNETT: AQUATIC BIOLOGY 175 bass showed well-developed homing in- stincts as did some other species (Lari- more 1952). Tests of the value of plant- ing 6— to 8-inch smallmouths in a stream already containing a population of smallmouth bass demonstrated that it was possible to build up numbers of these fish only temporarily. Minnows removed from a stream with an electric seine were replaced by other minnows through mi- gration and reproduction within a period of a few months (Larimore 1955). Ap- parently streams are quickly repopulated even when fish are killed by drought con- ditions, heavy winter ice, or temporary severe pollution. In studies of ponds and lakes, by 1945 evidence had accumulated to substantiate the idea that a lack of fish predators was an important problem to be faced in the management of these waters. Obviously, fishing was no substitute for natural pre- dation, and much of the task of the fish manager was that of functioning as a predator of small fishes (Bennett 1947). Fisheries technicians of the Illinois Natural History Survey using fish shocker for sampling the population of a stream. The shocker is a recent development that has been used successfully in both streams and lakes. 176 Studies on the effects of fish predators were begun with the placing of six short- nosed gars in a l-acre pond containing bass and bluegills; in this pond, bluegills were constantly in a state of overpopula- tion. Because the short-nosed gars were unable to reproduce in the pond, their numbers were easily controlled. From this experiment, Durham (1955) expand- ed the investigations of fish predation to include about a dozen additional ponds containing populations of stunted fish. Using gars and cormorants as predators, he was able to show improvement in growth and size of fish and an improve- ment in the survival rate of naturally produced bass. Ten years of recording catches of fish- ermen at Ridge Lake (Bennett 19542) gave a yield figure of more than 11,000 largemouth bass following an_ original stocking of 435; the fact that, in the last 6 years of the 10, 155,000 bluegills had been removed following an original stock- ing of 129 of these fish indicated that the bluegills were not only more prolific but showed a higher survival rate than the bass. The annual hook-and-line yield of bass varied between 10.9 and 30 pounds per acre, although the lake was not con- sidered a highly fertile one. During this time the standing crop of bass varied be- tween 30 and 50 pounds per acre. The success of a bass spawn (and survival) was negatively correlated with the num- bers of yearling fish present in the lake, particularly yearling bluegills. Young bass surviving to post schooling fry stage had about 1 chance in 35 of living to reach a size of 7 to 10 inches; natural mortality remained relatively high until the fish reached an average weight of 0.75 pound; then it dropped to less than 5 per cent per year until fish reached ages of 7 to 8 years, when the natural death rate again became high. With the system followed at Ridge Lake of culling the fish population at intervals of 2 years, the average length of bass at the end of the first growing season was 7.5 inches, at the end of the second growing season 10.8 inches, and at the end of the third 13.0 inches. The single most important finding at Ridge Lake was that a large new year class of bass could be produced at any spawning season by reducing the I-ttinois NaturaAL History SurvEY BULLETIN numbers of small bluegills in the lake prior to the spawning period. This re- duction could come about through arti- ficial culling of the fish population, or, as was later discovered, through concentrat- ing the fish during the fall months pre- ceding the bass spawning season by re- leasing a large proportion of the water from the lake and then allowing the lake to refill over winter. Studies of the ef- fects of these water releases, or draw- downs, were begun in 1951 (Bennett 1954b) and they are still in progress. Swingle & Smith (1942), working on fishes in Alabama ponds, built their man- agement practices around a program of pond fertilization; they recommended fertilization for ponds in other parts of the country. In order to test the useful- ness of fertilization as a pond manage- ment technique in Illinois, Donald F. Hansen began a testing program in ponds Vol. 27, Art. 2% 7 located on the University of Illinois Ex- — perimental Farm near Dixon Springs in southern Illinois, where soils are as poor as any within the state. After 7 years of fertilizing three ponds at various rates with complete fertilizers and using three other similar but unfertilized ponds for controls, Hansen concluded that the im- provement in fishing did not justify the cost of the fertilizer, if fish were cropped by hook-and-line. The unfertilized or con- trol ponds furnished better bass fishing than the fertilized ponds. Bluegills could be caught at a more rapid rate in the fertilized ponds, and the fish averaged larger in size. In terms of extra fish flesh produced by the fertilizer, the improved fishing cost about $1.00 per pound of fish. ‘Tests on various combinations of fishes in ponds have been going on for many years (Bennett 1952). The combinations used include largemouth bass—bluegill; largemouth bass—bluegill-warmouth—black bullhead; largemouth bass—bluegill—war- mouth—channel catfish; largemouth bass— golden shiner; largemouth bass—redear; largemouth bass-warmouth; largemouth bass-short-nosed gar; largemouth bass— bluegill-short-nosed gar; smallmouth bass alone; and largemouth bass alone. No combination appeared to be ideal, although several combinations proved to be as pro- ductive of good fishing as the highly ad- December, 1958 vertised largemouth bass—bluegill combi- nation. Redear sunfish, Lepomis microlophus (Gunther), were not reported from IIli- nois prior to 1945. In that year Dr. C. L. Schloemer, then located at Denton, ‘Texas, sent a small number of adult red- ears to the Natural History Survey at Urbana. These fish were placed in sev- eral ponds near Urbana, but none ap- parently survived the winter of 1945-46. In the spring of 1946 Dr. William E. Ricker, then located at Bloomington, In- diana, furnished 30 large adult redears from central Indiana. These fish were planted in several locations; 12 were placed in a stripmine pond, near Danville, that contained largemouth bass. ‘The redears in the stripmine pond multiplied very successfully and were the source for introductions into many lakes and ponds scattered through central and southern Illinois. Redears are now present in tribu- taries of the Illinois River (particularly the Sangamon) and in the Wabash drain- age along the eastern border of the state, as well as in the Big Muddy system of southern Illinois. As far as is known, all of these fish originated from the 12 fish released in the pond near Danville. In 1949 Starrett was placed in charge of the Natural History Survey labora- tory at Havana, where he began a study of Lake Chautauqua, a shallow flood plain lake of some 3,000 acres belonging to the U. S. Fish and Wildlife Service and used principally as a_ waterfowl refuge. This lake was fairly typical of other areas in the Illinois valley that had been leveed to keep out the river, pumped dry so that they could be used for farm- ing, and later flooded. We wondered about comparative over-all values of these areas for recreation (duck hunting and sport fishing), fish production (com- mercial fishes), fur production (native furbearers), and timber production (wood pulp), as contrasted with values of these areas for corn production that required government help in the con- struction and maintenance of _ levees, pumping costs and equipment, and sup- port of corn prices. In spite of the fact that recreational values are often intangi- ble, it soon became evident that the value of this area for fishing and recreational BENNETT: AQUATIC BIOLoGy U7) activities by people in the nearby indus- trial towns of Pekin and Peoria were much greater than the value of the corn the lake bottom would produce if the lake were drained (Starrett & McNeil 1952). In addition to studies in recrea- tional values, Starrett has made intensive studies of the fish and bottom fauna of Chautauqua and similar lakes, and the physical, chemical, and biological factors which influence them. Through the as- sistance of biologists from the Illinois Department of Conservation he has col- lected annual commercial fishing sta- tistics on all of the large Illinois rivers and information on native lamprey dis- tribution. In many of our operations during the past 20 years we have had the co-opera- tion of the Illinois Department of Con- servation: in pond management studies, stream investigations, surveys of the fishes of large rivers, and statistical studies on yields of commercial fishes. Some- times this assistance has been in the form of funds for construction works or for physical equipment, sometimes for half- time or full-time assistants; occasionally personnel of the Department have par- ticipated in operations requiring many men for a short period of time. This co- operation has not been based on written agreement; rather, it has come about through an understanding of mutual needs and interests by certain personnel of the Department, particularly Sam A. Parr, formerly Investigator, Inspector, and Superintendent of Fisheries, now Administrative Assistant to the Director of Conservation; and William J. Harth, recently made Superintendent of Fish- eries. We are grateful for this assistance and co-operation. DIRECTION OF FUTURE STUDIES In looking toward the future we find that some lines of research are taking shape now and others are still in the planning stages. One program that was begun in the spring of 1958 centers on a study of such basic concepts of .fish management as carrying capacity and standing crop, as well as the effects of cropping and 178 I-tinois NATURAL History SuRVEY BULLETIN stocking on populations of fishes. This work is centered at the Fin ’n’ Feather Club near Dundee. At the Eighteenth North American Wildlife Conference held in Washington, D. C., in 1953, Max McGraw, Presi- dent of the North American Wildlife Foundation, suggested the development of a fisheries research unit at the Fin ’n’ Feather Club. It was agreed that the McGraw Foundation (with the assist- ance of the Illinois Department of Con- servation) would develop a research unit of at least 15 l-acre ponds and provide space for laboratory and offices in the Fin ’n’ Feather Lodge. When this would be accomplished, the laboratory and pond unit would be assigned to the North American Wildlife Foundation, which in turn would assign the use of the facility to the Illinois Natural History Survey and the Illinois Department of Conserva- tion for fisheries research. Some progress had been made in physical plant con- struction by 1956, and on February 1 of that year David Homer Buck was em- ployed by the Natural History Survey to give immediate supervision to the project. Soon after, Maurice A. Whitacre, biolo- gist with the Department of Conserva- tion, was assigned to this program to work with Dr. Buck. At the beginning of the 1958 season 11 ponds were ready for use. Eight other ponds are in various stages of construction, and as these are completed they will be stocked and added to the units in operation. A second program, already begun, has to do with studies of the biochemistry of fishes. A chemical laboratory was de- veloped in conjunction with the aquarium laboratories in the Natural Resources Building at Urbana, and Robert C. Hilti- bran was employed on May 1, 1957, to begin biochemical investigations. Hilti- bran was forced to pioneer in this field because little research had been done on fish biochemistry. He has begun by studying the “normal” enzyme systems of the bluegill, Lepomis macrochirus Ra- finesque. Once the “normal” enzyme sys- tems are known, Hiltibran will measure the action of various chemicals on these Vol. 27, Art. 2 systems: waste products from commercial chemical processes and substances applied to aquatic areas for the control of noxious animals and plants. From these studies he may be able to suggest methods of re- ducing the toxicity of these chemicals to fishes and other aquatic organisms. Prior to 1934 Wilbur M. Luce (now Professor of Zoology, University of IIli- nois) and David H. Thompson developed a method for stripping and fertilizing sunfish eggs, which they used to produce hybrids between species of these centrar- chids. Luce raised many of these sunfish to maturity, and Thompson recognized that two of the hybrids were similar to fish pictured by Forbes & Richardson (1908) as being valid species. Recently we have revived the technique of artificial insemination of sunfish eggs in order to explore the possibility of developing hy- brids for use in fish management. In 1957. William F. Childers produced viable fry from all possible combinations of crosses of bluegills, redears, green sun- fish, and warmouths. Some of these com- binations appear to be superior to parent types. It is probable that within the next few decades great advances will be made in the management of fish populations for sport and commercial uses. Research basic to this management may lead to the discovery of ecological factors which con- trol the expansion of populations of im- portant sport species, such factors as have already been found for the large- mouth and smallmouth basses. Adjust- ments of these factors may be, to some extent, applicable to most natural waters, but they probably will be more practical in artificial waters and in controllable natural waters. It seems reasonable to as- sume that progress will be made in en- vironment control until waters can be made to produce crops of selected plants and animals much as terrestrial habitats can be made to produce wheat, rice, swine, and cattle. The development of water management may not only give ways to control the kinds and numbers of fishes but also to control the individual steps in the food chains of fishes. Wildlife Research ILDLIFE was high on the scale of human values during the period of discovery and initial settlement in IIli- nois. When the Illinois Natural History Society was founded in 1858, most II- linoisans were self-reliant farmers who measured values in terms of the length of fences constructed, the acreage of cleared forest land, the acreage of land under cultivation, and the extent of drainage programs, roadways, and railroads. The Illinois Central Railroad line from Chi- cago to the junction of the Ohio and Mis- sissippi rivers had been completed only 2 years earlier. Representative of the period are the reflections of Benjamin F. John- son, chairman of a committee for the examination of farms and nurseries for the Illinois State Agricultural Society. In reporting on improvements in “northern Illinois” following inspections in 1859 by the committee, Johnson (1861:84) un- doubtedly impressed members of the So- ciety when he stated that the progress of improvement in this portion of Illinois is little less than wonderful. Ten years ago much of the country was wild, open prairie; now there is scarcely a rood of un- inclosed land, except portions of the timber along the rivers and streams. ‘Today one cannot help but ponder why there weren’t a few rebels hardy enough to stand against the surge of progress and insist that Illinois, the settlers’ ‘prairie state,” set aside a prairie park or primitive forest for future generations. The loss of primitive areas and much of what went with them was accepted as inevitable. Even Dr. Stephen A. Forbes (19124:40), a giant among the naturalists of the time, pointed out that the reduc- tion and elimination of wildlife through settlement of Illinois by white man has evidently been a perfectly natural and inevitable one—as much so as the flow of the tide in the wake of the revolving moon —and immensely advantageous, also, from every point of view except that of the in- adequate, incompetent and ill-adapted popu- lation which it [settlement] has reduced or suppressed. Te OVA S 1G a CO) aa Dr. Theodore H. Frison (1938:19), who knew and understood Forbes as well as anyone, quoted the above statement as representative of the philosophy of 1912. DEVELOPMENT Wildlife research, as it is recognized to- day, first became evident in the annals of the Natural History Survey in the late 1870’s when Forbes initiated his inves- tigation of the food of birds. O. B. Ga- lusha (1881:238) provided insight into the conception of this research when, following Forbes’ presentation of a paper on the food of meadowlarks at the Janu- ary, 1881, meeting of the Horticultural Society of Northern Illinois, he observed that when a few of us, six years ago, met in the Normal University, as a committee of the State Horticultural Society, to inaugurate the enterprise, I had serious fears that the work was too great for accomplishment. These studies accompanied and _ prob- ably assisted in the accomplishment of the reorganization which converted the IIli- nois Museum of Natural History into a State Laboratory of Natural History on July 1, 1877. The reorganization was ac- companied by a new conception of pur- pose, relieving the members of the staff of the preparation of museum displays and allowing them to concentrate on research. Although I have been unable to uncover direct evidence of it, I feel certain that the change was manipulated by Forbes and members of the Illinois State Horti- cultural Society. Of legislative action ap- proved May 29, 1879, to become effective July 1, 1879, Forbes (1880f:1) gener- ously reported: We were also directed to investigate the large and intricate subject of the food of birds, in the interests of agriculture and horticulture, $200 per annum being voted for the expenses of this work. Forbes’ research on the food of birds was to become one of the outstanding con- tributions to avian biology. This research [ 179 ] 180 provides us with further insight into the motivations of the man who guided the program of the Natural History Survey and its parent organizations for many years (1872-1930). I have come to be- lieve that wildlife research made such an auspicious start in the Survey program not only because of Forbes’ professional quali- fications but also because of his intense desire to contribute to knowledge relating to human economy and welfare. W. L. McAtee (1917:249) believed that F. E. L. Beal and Forbes were “the founders of the scientific method of studying the economic value of birds.” Birds in Their Relations to Man (Weed & Dearborn 1903) is inscribed ‘“To Stephen Alfred Forbes . . . whose classic studies of the economic relations of birds will long re- main the model for later students.” In an early report Forbes (1882a:1) advised : The work of the State Laboratory of Natural History . . . is essentially that of a zoological and botanical survey of the State, conducted with principal reference to economic questions, and to the interests of public education. Although economic consideration con- stituted a principal responsibility, such a responsibility is adequately met only when men are willing to meet it and are capable of meeting it. If the desire had not been there, it seems likely that Forbes and his associates would have been content to occupy themselves with the systematics and descriptive records of the native flora and fauna, and wildlife research would have had to find its beginning at a much later date. I marvel at the courage of Forbes’ convictions when I consider the statement of Robert Ridgway (1901:1), a close associate of Forbes, on a prevailing attitude of the day: There are two essentially different kinds of ornithology: systematic or scientific, and pop- ular. The former deals with the structure and classification of birds, their synonymies and technical descriptions. The latter treats of their habits, songs, nesting, and other facts pertaining to their life-histories. . . . Popular ornithology is the more entertaining, with its savor of the wildwood, green fields, the river- side and seashore, bird songs, and the many fascinating things connected with out-of-door Nature. But systematic ornithology, being a component part of biology—the science of life —is the more instructive and therefore more important. Ittinois NaturAL History SurvEy BULLETIN Vol. 27, Art. 2 It is unfortunate that Forbes’ responsi- bilities were such that he could not have devoted more time to wildlife research, for he seems to have possessed an under- standing of wildlife biology which was much in advance of his time. In a single early paper (Forbes 1880a), a number of observations were made which, by their earliness, seem prophetic of views which are credited to relatively recent times. Current beliefs on predation may be seen in “the annthilation of all the established ‘enemies’ of a species would, as a rule, have no effect to increase its final average numbers” (Forbes 1880a:11). Forbes (1880a:8) recognized a need for an understanding of animal popula- tions long before they received serious study. Of this he wrote: Our problem is, therefore, to determine how these innumerable small oscillations, due to imperfect adjustment, are usually kept within bounds—to discover the forces and laws which tend to prevent either inordinate in- crease or decrease of any species, and also those by which widely oscillating species are brought into subjection and reduced to a condition of prosperous uniformity. It is apparent that this view implies population management in the modern sense. Further implications of manage- ment may be seen in the following statement by Forbes (1880a:4) : It is also plain that if man understands clear- ly the disorders which arise in the system of Nature as a result of the rapid progressive changes in his own condition and activities, and understands also the processes of Nature which tend to lessen and remove these dis- orders, he may, by his own intelligent inter- ference, often avoid or greatly mitigate the evils of his situation, as well as hasten their remedy and removal. Forbes (1880a:9) seems to have been well on the way toward an understanding of density dependent factors as used by today’s students of animal populations, as well as modern views on predation, when he wrote: “The fact of survival is there- fore usually sufficient evidence of a fairly complete adjustment of the rate of re- production to the drains upon the species.” That his understanding of the effect of density dependent factors on animal populations was astonishingly well advanced is evident in his (Forbes 18824:122) reasoning that excessive pop- ulations are, “in one way or another, self- ui December, 1958 limiting.” Earlier he (Forbes 1880a:5) had written that ‘as a general rule, the rate of reproduction is in inverse ratio to the grade of individual development and activity; . . .’ The “grade of indi- vidual development and activity” refers to the degree of evolutionary progress from a primitive form. Forbes (1880a:11) seems to have been grasping at the role of density independent factors in population control when he observed that the “real and final limits of a species are the inor- ganic features of its environment,—soil, climate, seasonal peculiarities, and the like.” What is today recognized as wildlife research continued to develop under Forbes’ guidance in the form of bird censuses. The results of these censuses are classics in American ornithology. They constituted the first extensive, quantita- tive investigations of bird numbers, or of any wildlife population for that matter, and introduced a census technique. Despite Forbes’ modern views, there is little evidence that he promoted wildlife management to any great extent. The thinking of Forbes (1912b:40) with re- spect to game management, despite earlier, more promising views, seems to have been limited to the encouragement of restric- tive laws, as evidenced by the following: “Our resident game birds would all have been gone long ago if it had not been for the restraints of law put upon the ac- tivities of the hunter... ” Forbes (1912b:46) made a plea for the Illinois Academy of Science to support by resolu- tion the “Anthony bill” (Migratory Bird Act of 1913), then under consideration in the House of Representatives. It should be remembered that legal protection was virtually the only management concept of the times. ORGANIZATION Game research in the modern sense be- gan to receive recognition in the Natural History Survey’s program in the early 1930’s. Probably stimulation was re- ceived from the federal government’s emphasis on conservation of natural re- sources, an emphasis that accompanied the search for work during that period of national economic emergency, and from Scorr: WILDLIFE RESEARCH 181 the influence of Herbert L. Stoddard (1931) and Aldo Leopold (1931, 1933). By that time, progressive leaders in the field realized that restrictive regulations and game farms were not meeting wild- life management needs. Also, it had be- come apparent that game _ populations could be managed wisely only when man- agement practices were based on a fund of pertinent and precise knowledge. Fri- son, who became Acting Chief of the IIli- nois Natural History Survey upon Forbes’ death on March 13, 1930, and then Chief on July 1, 1931, was among these leaders. An enthusiastic hunter, Frison had a con- suming interest in game management. Wildlife research was recognized in the organizational structure of the Natural History Survey for the first time when Frison (1938:31) established a Section of Game Research and Management on July 1, 1934. Dr. Ralph E. Yeatter, one of the nation’s first game specialists, was employed in this section. Frison initiated formation of the now well-established Midwest Wildlife Con- ference, and the first meeting was held in Urbana on December 5, 6, and 7, 1935. This meeting, known as the North Cen- tral States Fish and Game Conference, was the first regional conference of wild- life technicians in the United States. Frison (1938:27) described the confer- ence as essentially a fish and game clinic at which scientists from all the north-central states, without being dominated by administrators or the political type of conservationists, freely discussed wildlife management practices in an effort to winnow out the chaff from the wheat, to coordinate such researches and to orientate scientific studies of wildlife re- sources in such a way that demonstrable sound management practices would result. By 1936 Frison (1938:31) had con- cluded that experimental wildlife areas were needed for the purpose of testing management theories under practical con- ditions, a need which has still not been adequately met. A Section of Wildlife Experimental Areas was listed on the staff page of the Bulletin from March, 1938, to September, 1945. On June 1, 1938, a special program dealing with for- est problems in game management was un- dertaken by Dr. Lee E. Yeager, who had joined the staff in the Section of Forestry, 182 Ittinois NatruraAL History Survey BULLETIN Following passage of the Federal Aid in Wildlife Restoration Act in 1937, Frison undertook to arrange a co-operative wild- life research program with the Illinois Department of Conservation and the United States Bureau of Biological Sur- vey (now the U. S. Bureau of Sport Fisheries and Wildlife). The first co- operative project, “Illinois Fur Animal Resources Survey,” with Louis G. Brown as leader, was approved on May 23, 1939 (Frison 1940:8-9). In 1940 a Coopera- - tive Wildlife Restoration Program, em- bracing interagency co-operation in Fed- eral Aid, was listed on the staff page on the section level. Of this program Frison (1940:8) recorded: ‘General program planning and supervision of projects deal- ing with wildlife research have been as- signed to the Chief and various other members of the scientific staff of the IIli- nois Natural History Survey.” In evi- dence of its success this co-operative ar- rangement has survived through the years, and in 1956 the Conservation Advisory Board (Mann 1956:6) included, in a statement of policies, provisions for the development of an adequate game re- search program “through cooperation with and support of the Illinois Natural History Survey Division.” Thus, by 1940 Frison had stimulated and obtained support for a wildlife re- search program which involved the pri- mary activity of four sections within the Natural History Survey’s organizational structure. This compartition of the work was believed by those who knew Frison to have grown out of his extreme interest in wildlife resources and his desire to give each facet of study his personal direction. There was little change in the wildlife research program while Dr. Leo R. Te- hon served as Acting Chief, December 10, 1945, through February 28, 1947, follow- ing Frison’s death on December 9, 1945. Dr. Harlow B. Mills, who became Chief on March 1, 1947, proved to have the same consuming interest in wildlife research which had marked Frison’s lead- ership. In August, 1947, the Cooperative Wildlife Restoration Program was more properly designated Cooperative Wild- life Research, and a Section of Migratory Waterfowl was added to the organiza- Vol. 27, Art.2 © tion. The latter section had been discon- — tinued by June, 1948. Dr. Thomas G. Scott was appointed — the Head of the Section of Game Re- — search and Management on January 1, 1950. He was the first person to bear — this title. Soon after that date, arrange- ments were made for formal co-operation in wildlife research between the Natural — History Survey and Southern Illinois University, where Dr. Willard D. Klim- — stra was guiding the. program in wildlife research and education. That part of the — Survey’s organizational structure, operative Wildlife Research, which em- — braced the Federal Aid research, was — dropped, and the personnel and admin- — istrative responsibilities of this program were transferred to the Section of Game Research and Management in March, — 1950. On September 1, 1954, the Section of Forestry was abolished, and all of its wildlife activities and personnel trans- — ferred to the Section of Game Research ~ and Management. Thus, by 1954 all © wildlife research had been assigned to one — section. The name of the section was — more appropriately designated the Section — of Wildlife Research on May 1, 1956. — The area of research assigned to the sec- tion was similar to that of its predeces- — sors: the biology of warm-blooded verte- brates except that associated with taxo- In 1956 the ~ extensive activities of the section were — nomy and_ classification. divided and were assigned to branches to — provide for more effective supervision. The new branches were Nongame Birds, _ Upland Game Birds, Migratory Game ~ Birds, Mammals, Co-operative Wildlife — Research, and Environmental Research. As the first century of the Illinois Nat-— ural History Survey ends, interest in — wildlife resources of Illinois and other parts of the United States is greater than ever before. The number of people en- gaged in the wildlife management pro- — fession is at an all-time high and promises to go higher. Frison’s North Central States Fish and Game Conference has — so grown in attendance and extent of in- _ terest that its facilities no longer seem to meet the needs seen at the outset. As — a consequence, there is a tendency for — specialists to draw apart in committees or “councils.” Some of those who look Co- December, 1958 SCOTT: into the future to a greatly increased hu- man population and a more _ intensive land-use program seem to be returning to Forbes’ ‘‘let’s face the inevitable” phi- losophy of 1912. They seem willing to stand by while part of our wildlife her- itage, the prairie chicken, for example, goes down the drain. Foreign game birds are being feverishly investigated and _ re- leased with the hope of finding species which will supplement populations of na- tive game birds being reduced by a chang- ing habitat. In anticipation of the time when shootable wild game populations will no longer meet the demand, there are the programs for pen-rearing game birds to be released under the gun. The root- ing out of osage orange hedges throughout the state is symbolic of the cancerous-like growth in activities designed to bring in- creasing amounts of land into agricul- tural, residential, or industrial use. Public realization of the vital importance of habitat in the management of a wildlife resource is showing growth; however, the area of desirable wildlife habitat, espe- cially that for upland species, is continu- ing to shrink. Thus, the most perplexing problem of the wildlife manager in [Ili- nois today is that of developing and pro- tecting suitable habitat. RESEARCH CONTRIBUTIONS A review of outstanding contributions made to wildlife biology and conserva- tion by employees of the Illinois Natural History Survey and its parent organiza- tions will aid understanding of work in these fields during the first 100 years. A few publications by non-Survey personnel are cited to provide perspective or to recognize Survey publications by workers who were not employed by the Survey. Birds Contributions on the biology and con- servation of birds may be conveniently grouped into three classes: those for non- game, those for upland game, and those for migratory game birds. Nongame Birds.—Of the meadow- lark, Forbes (18815:234—-5) wrote: He is first cousin to the Indian, the prairie- wolf and the badger, but with a better knack WILDLIFE RESEARCH 183 than they at adapting himself to the new life of civilization. He is a perfect reflection of his most constant surroundings—with a bosom of prairie butter-cups, a back like the dead grass of autumn, and a song that harmo- nizes well with the whistling of prairie winds. This colorful description reveals some- thing of Forbes’ deep feeling for birds. Sentiment, however, is not evident in his systematic and painstakingly conserva- tive evaluations of the place of birds in an economic scheme of things. Forbes’ research on the food of birds constituted a milestone in ornithological history. ““No part of the recent work of the Laboratory has excited a wider inter- est than that relating to the food of birds’ (Forbes 1880f:7). This work established Forbes among contemporary ornithologists as the ranking authority on the insect food of birds. Dr. Elliott Coues (1883:105) believed him to be “Our best authority upon the insect food of birds...” Drs. Clarence M. Weed and Ned Dearborn (1903:19-20) con- sidered Forbes’ publications on the food of birds to be ‘“‘classic papers” and “‘the basis for the modern development of economic ornithology.” The findings of Forbes’ studies of the food of birds appeared in a number of papers. ‘The most substantial contribu- tions, however, were brought together in two papers (Forbes 1880d, 1883a). The first dealt with the food of certain birds in the families Mimidae and Turdidae. The second reported observations on the regulative action of birds feeding on an excessively high population of canker- worms and vine leaf chafers. The latter paper, “The Regulative Action of Birds Upon Insect Oscillations,” was approved by Indiana University in fulfillment of Forbes’ thesis requirements for the Ph.D. degree granted in 1884 (letter of May 2, 1952, from E. Lingle Craig, Reference Librarian, Indiana University, to Mar- guerite Simmons, Librarian, Illinois Nat- ural History Survey). Of lesser im- portance were notes on the food of the meadowlark (Forbes 18814), the English sparrow (Forbes 1881c), and the kinglets (Forbes 1883d). The scope of these investigations may be seen in the following report (Forbes 1882a: 5-6) : 184 Inuinors NaruraAt History Survey BULLETIN The collection designed to illustrate the food of birds has been more than doubled in the last two years, and now numbers over six thousand stomachs, representing about two hundred species. Eight hundred and eighty of these have now been exhaustively studied, ... Unfortunately, the analyses were ap- parently discontinued at this point, for there were no more publications on the food of birds, and the annual reports of the State Laboratory of Natural History indicate that nothing further on this sub- ject was done. Forbes’ evaluations of his findings on the food of birds indicated awareness of the need for giving special consideration to the high mobility of birds, food prefer- ences, density effects, ability to diversify diet, and the importance of seasons, geo- graphic location, and specific ecological circumstances. Forbes (1880e:122-3) de- scribed what appears to have been a new method of evaluating proportions of food in the stomachs and crops of birds, a technique which is used yet today. He (Forbes 1881a:107) also showed himself to be aware of the importance of sample size and made crude tests for significance by comparing the results of analyses of small samples with those of larger samples to determine whether there were important departures in the pattern of the diet. Because Forbes believed that the num- bers and kinds of birds in specific habitat categories needed to be known before their economic importance could be evalu- ated, he encouraged studies based on sys- tematic censuses, which were carried out in 1906, 1907, 1908, and 1909. These studies are classics in American ornithol- ogy and introduce a new censusing tech- nique for birds. | believe them to be the first extensive statistical analyses of bird populations in this country. Although the results of these surveys are presented in six papers, two of them contain most of the data (Forbes & Gross 1922, 1923). Unfortunately, a final paper in which it was hoped to present all of the findings for each species was never published. Plans for this paper are described (Forbes & Gross 1923:397) as follows: It has been our general plan to work at first with broad strokes of the full brush, refining upon our neutral background by degrees and ending, as we hope to do in a paper follow- 3Z Vol. 27, Art. 2 | ing the present one, with the final details for — each species taken up separately and followed — all over the state and around the year. Forbes’ experience with plankton sur- veys guided him in the development of — the census technique devised specifically — for the bird surveys (Forbes & Gross 1921:1). Forbes believed that two men walking abreast could identify and count all of the birds flushed by them or cross- ing their track on a strip 150 feet wide in relatively open country but 60 feet — wide in heavier cover, such as orchards, open woods, and patches of close shrub- bery. This census technique was pictured (Forbes & Gross 1921:1) as a huge net a hundred and fifty feet wide, drawn in straight lines across every kind of crop or other surface vegetation, by which all the birds found there should be caught and held unt:! they had been identified and counted. Results were obtained by application of this census technique during the summers of 1907 and 1909 (Forbes & Gross 1922:189, 199); the census indicated an average of 852 birds per square mile for the state as a whole. The numbers of birds per square mile showed a striking increase of 5+ per cent from the 1907 fig- ure to that of 1909. Orchards were found to have the greatest numbers of birds per square mile, 3,943; yards and gardens were a close second with 3,418. The state- wide number of birds per square mile in winter was estimated from data collected in 1906 and 1907 to have been 520 (Forbes & Gross 1923:398). Dr. Frank Smith (1930) prepared a thorough and useful paper dealing with a chronology of the spring migration of 221 species of birds through Urbana from 1903 throuzh 1922. The objective of the study was to determine whether there was a correlation between migration flights of spring migrants and certain kinds of weather. Smith (1930:112) concluded: A careful study of the weather maps during the time when records were being made re- vealed that the greatest migratory activity in spring occurred at times when the weather maps showed an area of low barometric pressure approaching from the west, with the south winds and rising temperatures which normally accompany such movements. The monograph by Dr. Alfred O. Gross (1921) on the dickcissel must be December, 1958 Scott: WILDLIFE RESEARCH 185 classified as one of the outstanding early studies of its kind. I was especially im- pressed by his statistical evaluation of the abundance of the bird in relationship to Ornithologists in winter equipment ready to State Laboratory of Natural History, about 1906. is Howard A. Ray. habitat categories. He found that hay- fields constituted preferred habitat; with- in this classification, clover and alfalfa were preferred to other kinds of hayfields set out on a collecting expedition for the Illinois At the right is Alfred O. Gross, and with him 186 ILtLinois NATURAL available at the time. Perhaps it is also appropriate to mention the paper by W. E. Loucks (1894) on the prothonotary warbler. While the paper is unfortu- nately more subjective than objective, it constitutes a colorful record of the find- ings of a talented observer. The participation of the Natural His- tory Survey staff in the effort to obtain legal protection for all hawks and owls in Illinois merits attention. At the urging of Dr. David H. Thompson, Director Ralph Bradford of the Illinois Depart- ment of Conservation sought and obtained legislation, effective July 1, 1929, to pro- tect all hawks and owls except the great horned owl, the goshawk, sharp-shinned hawk, Cooper’s hawk, duck hawk, and pigeon hawk. Members of the Natural History Sur- vey staff continued to advocate ig ew of hawks and owls, and, effective July 1, 1941, protection was obtained for all but the great horned owl. This condition pre- vailed until July 1, 1947, when, for some unexplained reason, the Cooper’s and sharp-shinned hawks were removed from the protected list. In 1956 and 1957 a new effort, spearheaded by Elton Fawks, representing the Illinois Audubon Soci- ety, was made to obtain protection for all hawks and owls. I presented a paper at the annual meeting of the Natural Re- sources Council of Illinois on October 20, 1956; this paper has been credited with having much to do with winning the sup- port of the Council and member clubs for the needed legislation (Fawks 1957:1). I read a second paper at the annual meet- ing of the Illinois Audubon Society in Rockford on May 18, 1957, at the time the bill was before the legislature (Bay- less 1957:3), and I made an appeal for further support in the official publication of the Illinois Federation of Sportsmen’s Clubs (Scott 1957). Dr. Richard R. Graber assisted this effort by analyzing data on hawk and owl numbers reported in the Christmas counts of the Illinois Audubon Society for the past 50 years and by demonstrating that some species had declined in numbers and that there was no evidence of need for measures de- signed to reduce hawk and owl popula- tions. The bill proposed for the protec- tion of hawks and owls, House Bill No. Hisrory Survey BULLETIN Vol. 27, Art. 2 1063, included protection also for the crow, blue jay, cowbird, and grackle by the time it had passed the General As- sembly, June 27, 1957, and was signed into law by Governor William G. Strat- ton, July 8, 1957 (Illinois General As- sembly 1957:1937-8). The bill pro- vided for amending Section 21 of the Game Code to define all hawks and owls as protected species but, as a consequence of an oversight, Section 36 of the Code was not amended to include the Cooper’s hawk, the sharp-shinned hawk, and the great horned owl among the hawks and owls which were unlawful to have in pos- session at any time. The Prairie Chicken.—lIf the IIli- nois farmer of the 1860’s had taken time from his backbreaking work to sit down and figure out the cause of the enormous populations of prairie chickens which he alternately cursed and blessed, perhaps he would have seen that he had just com- pleted a gigantic habitat development project for upland game birds. He had extended the range of the chicken by clear- ing the timberland, and he had provided thousands of food patches by establishing grainfields. From these high populations, the prai- rie chickens declined in numbers with the gradual increase in grain farming and the accompanying reduction of grassland. The hunting season on prairie chickens was closed in 1903 and was not opened again until 1911. The relaxation of hunt- ing regulations at this time undoubtedly followed an increase in the population, probably associated with “The Indiana ‘Comeback’ of 1912” (Leopold 1931: 172). Contemporary data for Illinois had apparently not been called to Leo- pold’s attention because Forbes (1912b: 47-8), reported that prairie-hens—thanks to our protective laws— are now to be seen in at least seventy-four counties, so abundantly in some that farmers are beginning to protest against their further increase because of the amount of grain which they devour. The records on which this statement is based remain in the files of the Illinois Natural History Survey. Re-examination of them brings out the conservativeness of Forbes, for they indicate that the re- porting observers had found a few prairie December, 1958 chickens in all of Illinois’ 102 counties except 10 (Yeatter 1957:8). Despite an exaggerated confidence in protective regu- lations, Forbes (1912b:48) recognized the basic environmental factor which was limiting the prairie chicken population be- cause he advised that: The very country in which it was formerly most numerous—that is, the open prairie— is now least favorable to it because of the agricultural operations, which disturb and destroy it during its breeding season. When it again became evident that the prairie chicken population was endan- gered, Director Bradford of the Depart- ment of Conservation, at the urging of Dr. Thompson of the Natural History Survey, obtained legislation, effective July 1, 1933, to prohibit the taking of the prairie chicken at any time. No open sea- son on this bird has been permitted since that date. It seems fitting that, with the upsurge of interest in wildlife conservation in the 1930’s, one of the first comprehensive studies of a game species to be undertaken in Illinois was concerned with the prairie chicken. The valuable monograph (Yeat- ter 1943) resulting from this study in- cludes data on early distribution, range, life history, populations, mortality causes, food habits, and management. I believe that this publication was the first to direct attention to the importance of grass-seed farming in the management of prairie chickens. Yeatter (1943:409) advised that areas harboring a few prairie chick- ens might be converted into good chicken range by leasing, and converting to refuges for a term of years, 25 per cent of the total land in the form of 20-acre, 40-acre or larger tracts of the poorer farm soil throughout each township. In a later publication Yeatter (1957:8) revised his recommendation on grassland refuges to a minimum of 40 acres in each square mile of farm land. When unusually large numbers of young prairie chickens were found dead on a study area in Jasper County in 1935 and 1936, an investigation of parasites as a possible cause of these deaths was un- dertaken (Leigh 1940:186). Tapeworms were found in 10 of 14 partly grown birds and in not one of 14 adults which were Scott: WILDLIFE RESEARCH 187 collected in Jasper and Richland counties in the summers of 1936 and 1937. Because cestodes of a previously undescribed species of Raillietina occurred in 10 [ac- tually 9] of 14 young birds and in 4 cases were sO numerous or so large as to occlude the lumen of the greater part of the small intestine, they should not be overlooked as a factor in prairie chicken mortality (Leigh 1940:188-9). Shelford & Yeatter (1955) interpreted year-to-year population fluctuations of male prairie chickens during a period of 18 years on the study area near Hunt in Jasper County, Illinois, in relation to weather and climate. Field observations indicated that the period of the late stages of development of the reproductive cells during April, the period of egg-hatching in June, and the period when young prai- rie chickens were 4 to 8 weeks old were critical times in the reproductive cycle of prairie chickens. Many trials in which various weather records were used showed that the population level tended to re- spond to only two weather combinations: (1) rainfall and sunshine in April and (2) rainfall and temperature in June. Reproduction was most successful in sea- sons when April rainfall averaged 2-5 inches and when 48-64 per cent of the possible hours of sunshine were experi- enced. As the amounts of rainfall and sunshine varied from these optimum lim- its, reproductive success became progres- sively lower. Thus, the prairie chicken in Illinois has passed from the enormous populations of Civil War times to small, scattered colo- nies, in only 24 counties in 1957 (Yeatter 1957). It seems evident that the prairie chicken will soon become something of the past in Illinois unless a positive pro- gram of management such as that being proposed at the present time saves them. The Bobwhite Quail.—vTo the up- land bird hunter of Illinois, events which established the present boundaries of IIli- nois proved inadvertently provident, for they led to the inclusion of excellent quail range over the southern one-third of the state as well as what was to become fairly good pheasant range in the northern one- third. Illinois has the distinction of being the locale of the first systematic and extensive 188 census of quail populations. These cen- suses were carried out during the period 1906-1909 by a strip-census technique (Forbes & Gross 1921, 1922, 1923). The increase in the density of quail popula- tions from north to south in Illinois was just as clearly marked in the findings of Forbes and Gross as it is today. Cen- suses during the summers of 1907 and 1909 revealed quail populations of 21 birds on 7,966.5 acres or 1 bird per 379.4 acres in northern Illinois, 53 birds on 5,823.9 acres or 1 bird per 109.9 acres in central Illinois, and 241 birds on 5,527.2 acres or | bird per 22.9 acres in southern Illinois (Forbes & Gross 1922:191, 197). A similar distribution of quail popula- tion densities was evident in the winter counts made during the period November 23, 1906, through February 21, 1907, when 180 quail were counted on 1,422.4 acres or | bird per 7.9 acres in southern Illinois and 54 on 4,956.0 acres or 1 bird per 91.8 acres in central and northern Illinois combined (Forbes & Gross 1923: 398, 400). The data for the counts made during the summers of 1907 and 1909 in- dicated an increase in quail populations for the state as a whole; 91 quail were counted on 7,693.6 acres, 1 bird per 84.5 acres, in 1907 and 224 birds on 11,624.1 acres, 1 bird per 51.9 acres, in 1909 (Forbes & Gross 1922:191). The densities of quail populations were recorded by general habitat category. In a special study, August 19 to September 15, 1908, in which orchards in the vicin- ity of Centralia and Olney received spe- cial attention, 774.5 acres of orchard and 594.5 acres in other habitat categories were censused ; 356 quail, 1 per 2.2 acres, were counted in the orchards and 32, 1 per 18.6 acres, outside the orchard area (Forbes & Gross 1921:5, 7). The im- portance of undisturbed grassland to the management of quail was suggested by Forbes & Gross (1921:3) in their consid- eration of reasons for the high densities of quail in orchards when they concluded: “Evidently it is not the trees that attract it, but the cover afforded by an undis- turbed growth of grass and weeds be- tween the rows.” Following these early censuses, there Was a pause in the attention given quail by Natural History Survey researchers. ILtinois NATURAL History SURVEY BULLETIN Vol. 27, Art. 2 The species did not become the subject of further study until the hunting season of 1936, when 141 quail were collected in an investigation of helminth parasites by Leigh (1940:186, 190), who concluded “that the quail of Illinois are not so heav- ily infested with the diversity of helminth parasites as are the quail of the southeast- ern states.’ In the summer of 1938 a brief investigation of quail productivity in Calhoun County was carried out by Bell- rose (1940:10), who pointed out the im- portance of undisturbed grassland and concluded that the possibilities for provid- ing suitable nesting sites were greatest in apple orchards. In 1948 and 1949 the hatchability of the eggs of the bobwhite was compared with that of the eggs of pheasants after experimental exposure to temperatures of 62, 73, 78, 83, and 88 degrees F. for a period of 7 days to simulate preincubation exposure (Yeatter 1950:529). Yeatter (1950:530) concluded that “No signifi- cant reduction of hatchability of the bob- white eggs by high temperatures was evi- dent.” Bobwhite quail were investigated from 1948 to 1954 on the Crab Orchard Na- tional Wildlife Refuge, in Williamson County, to determine what types of cover importantly influenced the abundance of quail (W. R. Hanson & R. J. Miller un- published MS). Quail abundance was significantly correlated with the amount of “edge” between cultivated fields and brushy pastures. Twenty-five linear miles of multiflora rose hedges, planted on an area of about 5.5 square miles, failed to increase the numbers of quail. A most important step was made in the direction of a thoroughgoing investigation of the biology of the bobwhite quail in Illinois by the signing, on October 3, 1950, of a memorandum of understanding providing for co-operation between the Natural History Survey and Southern Illinois University. The observations and impressions (Scott & Klimstra 1954) ob- tained during a trip to quail management areas in southeastern United States for the purpose of co-ordinating this co-oper- ative program of research in Illinois with work elsewhere are believed noteworthy and cover the following subjects: hunting, management of habitat, and populations. i December, 1958 ScorT: The co-operative research has involved nearly all phases of quail biology and an experimental habitat management pro- gram. Among the important contributions are two studies, one on the diet of quail (E. J. Larimer unpublished MS) and the other on quail populations on an unman- aged area. he second study has empha- sized once again the great importance of undisturbed grassland to quail productiv- ity and provided evidence of the amount and distribution of undisturbed grassland required to insure high quail productivity. The quail investigations have received outside financial assistance from Max McGraw, A. E. Staley, the North Ameri- can Wildlife Foundation, and the United Electric Coal Company; the coal com- pany also has made available extensive landholdings for experiments with habitat management. The Ring-Necked Pheasant.—Al- though the attempt to establish pheasants in Illinois had gotten under way in the 1890’s, this state’s biological research- ers were apparently unimpressed with it as a subject for investigation. In a dis- cussion of the animal resources of the state, Forbes (1912b:48) advised that he had not had time to appraise efforts to im- prove “the composition of our fauna by the introduction of exotic species.” Little or no attention was given pheasants until Leigh (1940:190) made his limited sur- vey of the parasites of pheasants collected during the hunting season in 1936. Dur- ing the summer of 1938 Bellrose (1940) made nesting studies and population esti- mates of pheasants in the southern part of Calhoun County, which is outside the recognized range of pheasants in Illinois. His observations (Bellrose 1940:9) ap- peared to indicate that this population had been maintained by repeated releases. Intensive investigations of the ring- necked pheasant did not get under way until April 1, 1946, when the Illinois De- partment of Conservation, the U. S. Fish and Wildlife Service (now the U. S. Bu- reau of Sport Fisheries and Wildlife), and the Illinois Natural History Survey entered into a co-operative project with Federal Aid funds. Dr. William B. Rob- ertson (1958) described the results of this co-operative research from inception to December 31, 1951, together with an WILDLIFE RESEARCH 189 account of the early history of pheasants in Illinois and an analysis of the factors limiting the pheasant range. His report constitutes the first com- prehensive account of pheasant research in Illinois. It is a valuable historical rec- ord of early introductions of pheasants and the development of hunting regula- tions. Curves based on an annual aver- age of over 300 dates of the hatching of eggs in nests were constructed and ana- lyzed for effects of photoperiod, weather, and farming operations. Observations made on the breeding behavior of marked birds released in Kendall County are be- lieved to be especially enlightening. Of particular note to students of populations and behavior was the observation that adult hens tended to become associated in the harems earlier than did juvenile hens. One of the earliest attempts to eliminate bias from evaluation of the worth of artificial stocking is reported upon in the paper. Robertson (1958: 129) concluded “that 35 to 50 per cent of the cock pheasants in summer releases in Illinois were bagged in the succeeding hunting season. ‘The recovery rate for spring-released adult cocks, estimated by similar methods, was only 6.1 per cent.” In Livingston County a release of 1,000 adult hens in September of 1948 resulted in a survival of about 50 per cent to May, 1949; released hens made up one-third of the hens on the area at the latter date. It was found that about 33 per cent of the broods seen the following summer were accompanied by released adult hens. In Kendall County the effect of a release of 500 adult hens in August and 1,000 ju- venile hens in November and December of 1949 was evident when it was seen that 25 per cent of the broods in 1950 were accompanied by released hens. There has been much speculation as to the reason pheasants have failed to be- come established in southern United States. During brood studies beginning in 1937, Yeatter (1950:529) observed that the hatchability of pheasant eggs fre- quently declined in late spring in east- central Illinois, which is on the southern edge of the pheasant range. This observa- tion suggested that high environmental temperatures at the time of egg-laying con- stituted a critical limiting factor. In 1948 190 Ittinois NATURAL History SuRvVEY BULLETIN and 1949 Yeatter (1950:529) compared the effect of temperature on paired lots of pheasant and quail eggs during a 7-day preincubation period and stated “that the hatchability of pheasant eggs was reduced by heat exposures, the reduction increas- ing with the higher temperatures.” It was concluded that this vulnerability of pheasant eggs to high air temperatures constituted an important barrier to the southern distribution of pheasants, and it was suggested that pheasants in the south- ern Pacific Coast and Rocky Mountain regions might be more tolerant of higher temperatures. Recent experiments by Yeatter lend strong support for this sur- mise (Yeatter unpublished MS). At the present time, the Illinois De- partment of Conservation, the Illinois Natural History Survey, and the U. S. Bureau of Sport Fisheries and Wildlife are co-operating in a comprehensive and intensive investigation of the ring-necked pheasant. This research is being carried on by Dr. William R. Hanson, Dr. Fred- erick Greeley, Jack A. Ellis, and Ronald F. Labisky and involves study of range- limiting factors, the biology of pheasants within the established range, and experi- ments with the establishment of self- maintaining populations outside the ex- isting range. The Canada Goose.—Canada geese wintering on the islands and bars in the Mississippi River from Chester, Illinois, southward to Cairo must have found the fight for survival during the early part of the twentieth century severe indeed. The conservationists who, with the ob- jective of providing for pole-and-line fish- ing, arranged for the purchase of Horse- shoe Lake, an ancient oxbow of the Mis- sissippi River in Alexander County, by the Illinois Department of Conservation in 1927 were unaware of the part they would play in protecting this goose popu- lation and setting the stage for its future growth. About 1,900 Canada geese win- tered at Horseshoe Lake, now famous as the Horseshoe Lake Game Refuge, dur- ing the first year. During the winter of 1957-58, about 225,000 Canada geese wintered in southern Illinois; these geese constitute a resource which has been esti- mated to contribute about $1,500,000 an- nually to the economy of southern []linois. Vol. 27, Art. 2 The refuge was soon surrounded by commercial shooting clubs, and a problem which attracted national interest was created. Leopold (1931:206) wrote: “The question of whether public refuges should be surrounded by public shooting grounds is frequently debated. Horse- shoe Lake in Alexander County, Illinois, is a good place to study the question.” Nevertheless, it was not until 1939, when about 40,000 (the same number estimated to have been killed in southern I[Ilinois in 1957) geese were wintering at the refuge, that the annual kill and the need for knowledge on which to base intelligent control became alarming enough to at- tract researchers. In 1940 Arthur S. Hawkins initiated the Illinois Natural History Survey’s long-time research program on Canada geese (Hanson & Smith 1950:70), and in 1941 geese were banded in the area for the first time by Hawkins and John M. Anderson. ‘The initial effort was necessarily directed toward the develop- ment of efficient trapping and handling methods (Hanson 1949a), and colored bands were tested on geese (Balham & Elder 1953) for the first time. The massing of so large a portion of the Canada geese of the flyway at Horse- shoe Lake created a unique opportunity for population research. Practical meth- ods for aging geese were worked out for the first time (Elder 1946; Hanson 1949b, 1953a), and these methods, which were used for measuring the composition of the population, formed the basis for all subsequent investigations. Elder’s (1946:94-8) analysis of the weight of Canada geese by sex and age constituted the first analysis of its kind for geese. Hanson (1949) developed techniques for placing Canada geese in three age categories (juvenile, yearling, and adult), thus making possible a considerable ad- vancement in the understanding of popu- lation mechanics in these birds. A definitive investigation of the biol- ogy of the Canada goose constitutes the long-range objective of the research on this species. Early findings were reported in a 144-page article (Hanson & Smith 1950). In this article the four flyway populations of Canada geese breeding in the general area of Hudson Bay were December, 1958 revealed for the first time. “The breed- ing range, migration routes, wintering grounds, and populations were discussed for each flyway population. Later, the South Atlantic Flyway population was treated in greater detail (Hanson & Grif- fith 1952). Observations on the relation of hunting losses to the age structure of the population wintering at the Horse- shoe Lake Game Refuge proved especially useful. The heavy kills of immature geese in the first half of the 1940’s not only altered the age composition of the flock but reduced the average longevity of these geese as shown by life survival indices, the first constructed for a species of waterfowl (Hanson & Smith 1950: 172-88). A recent 3-year study of the kills of Canada geese by the natives of the Hudson-James Bay region has estab- lished the location and size of these hunting losses with exactness (Hanson & Currie 1957). The Canada geese on the Horseshoe Lake Game Refuge provide a unique op- portunity for study of behavior. The adult males of the largest families usually dominate males leading smaller families, and the social rank of the adult female is determined by that of her mate (Han- son 19535). The conception ‘that the small goose flock is usually a family and that larger flocks are frequently multiples of families rather than mere aggregations of individuals . . .” also became apparent in observations made at the Horseshoe Lake Game Refuge (Elder & Elder 1949:139). Diseases and parasites of Canada geese have been investigated in anticipation of epizootics among geese crowding into winter refuges. Blood protozoa (Levine & Hanson 1953) and microfilaria (Han- son, Levine, & Kantor 1956; Hanson 1956) have been surveyed. The preva- lence of helminths in relation to age and the incidence of Leucocytozoon infection in immature geese are currently under study. Dr. Norman D. Levine (1953) made a valuable review of the literature on coccidia in the avian orders Galli- formes, Anseriformes, and Charadri- iformes. Coccidial infection was initially investigated in the flock at the Horseshoe Lake Game Refuge by Levine (1952), and the coccidia of North American wild Scott: WILDLIFE RESEARCH 191 geese and swans were subsequently con- sidered by Hanson, Levine, & Ivens (1957). Host specificity of some species of coccidia was shown, and certain coc- cidia seemed restricted to one flyway popu- lation. Thus, coccidia appeared to offer promise as biological tracers for confirm- ing the distribution of flyway populations indicated earlier by band _ recoveries (Hanson & Smith 1950:74-9). Ducks.—The early settler found mul- titudes of ducks in Illinois, not only along major streams, but also on the prairie sloughs. ‘The vast numbers of ducks migrating through the bottomlands of the Illinois River valley made this valley a famous shooting ground as far back as the 1880’s. Indeed, in 1886, a group of businessmen from the Peoria area founded the Duck Island Preserve, probably the first hunting club in the state. Prior to 1900 the Illinois River and its connecting waters were in a near pristine condition. Sloughs and lakes con- tained an abundance of aquatic vegeta- tion (Kofoid 1903), which provided food for ducks; other food was furnished by pecan nuts and pin oak acorns which be- came available when high water flooded the low-lying, timbered bottoms. In January of 1900 the Chicago Sanitary and Ship Canal was opened, greatly in- creasing earlier diversion of water from Lake Michigan (Mulvihill & Cornish 1930:53). This increased diversion re- sulted in water levels which were high enough to destroy extensive tracts of bot- tomland timber, including most of the pecans and pin oaks, in the Illinois River valley. During the early 1900’s not only were the tracts of mast-producing trees, so im- portant as sources of food for mallards, lost to the ducks, but drainage destroyed many other important feeding grounds. Between 1900 and 1922, almost 200,000 of 400,000 acres in the flood plain of the Illinois River valley were leveed and drained (Mulvihill & Cornish 1930). The number of ducks in the lower flood plain area and shooting success declined when the mast-producing trees were lost. Then the practice of feeding waterfowl was begun at some duck hunting clubs in the early 1900’s, was prohibited by state 192 IL~tinois NATURAL History SURVEY BULLETIN law from 1909 to 1911, became a wide- spread practice in the 1920’s, and was prohibited by federal regulation in 1935 (Bellrose 1944:333). Finally, in recognition of the import- ance of waterfowl problems in Illinois, the Natural History Survey employed Arthur S. Hawkins and Frank C. Bell- rose to initiate a waterfowl research pro- gram in 1938. Up to that time, the study Vol. 27, Art. 2 fect of baiting and live decoys on water- fowl and “estimated that 6,000,000 bushels of corn were fed by Illinois clubs during the 1933 season’ (Bellrose 1944: 365). About 1938 initial attention was given to the wood duck, and in 1939 the first successful nesting box of rough-cut lum- ber was developed for this waterfowl spe- cies (Bellrose 1953a). By experimenta- ee Wildlife technicians preparing to fluoroscope a mallard drake at the Illinois Natural His- tory Survey field laboratory near Havana. The fluoroscope has facilitated studies involving crippling by hunters and lead poisoning. of waterfowl had received little attention in Illinois. In 1922, at duck hunting clubs near the mouth of the Sangamon River, Dr. Frederick C. Lincoln (1924) of the U. S. Bureau of Biological Survey (now the U.S. Bureau of Sport Fisheries and Wildlife) made the first large-scale bandings of ducks in North America. Francis M. Uhler of the same agency examined the food contents of duck giz- zards collected at the Duck Island Pre- serve in 1933 (Uhler unpublished re- port). Also, Uhler investigated the ef- tion, a nest box entrance with a 4-inch horizontal measurement and a 3-inch vertical one was evolved in 1942 for the purpose of excluding raccoons which were preying upon the hens and their eggs. In 1950, a cylindrical, galvanized metal house was developed to exclude fox squir- rels, as well as raccoons, as predators on wood duck eggs. Because diversion of Lake Michigan water, drainage, and sediment decreased the duck foods in the Illinois River val- ley, several of the early investigations December, 1958 ScoTrT: dealt with duck food plants. A study of the ecology of aquatic and marsh plants revealed the relationships of fluctuating water levels and turbidity to plant growth (Bellrose 1941). As a result of this study, two techniques for production of duck foods were recommended: (1) dewatering certain areas to encourage growth of moist-soil plants on exposed mud flats and (2) stabilizing water levels at depths of 2 to 3 feet to promote growth of aquatic plants. A study of the relative value of various plants as duck foods (Bellrose & Ander- son 1943:432-3) showed that moist-soil plants, such as rice cut-grass, millets, smartweeds, and nutgrasses, were much more valuable as duck foods than such aquatic and marsh plants as the pond- weeds, coontail, duck potato, and bur-reed. This study is believed to be the first in which the food habits of waterfowl were related to food availability. Later, a study by Low & Bellrose (1944:21) re- vealed that, among 28 waterfowl food plants, 6 of the 7 heaviest seed producers were emergent or moist-soil plants. Harry G. Anderson (unpublished MS) made a little known but substantial con- tribution to knowledge of the diet of ducks in Illinois when he analyzed and reported upon the contents of 4,977 giz- zards of ducks, representing 17 species, taken during the hunting seasons in 1938, 1939, and 1940. In a sense, Illinois is at the bottleneck of the Mississippi Flyway, the flyway with the largest population of ducks in North America. The resulting constric- tion of duck populations streaming into Illinois has provided a remarkably fine opportunity for study of flyway popula- tions. A comprehensive investigation of sex and age among ducks, covering 1939 through 1954, has been completed (Bell- rose, Hawkins, Low, & Scott unpublished MS). From 1938 through 1958, periodic censuses have been taken of waterfowl populations in the Illinois River valley during fall, winter, and spring. In 1946 the census route was expanded to include the Mississippi River valley between Rock Island and Alton. ‘These censuses have provided information on the effect of weather, water levels, food, and refuges upon waterfowl populations. WILDLIFE RESEARCH 193 A 5-year investigation of duck popula- tions and kill by hunters revealed that “altering the length of the season is one of the most expedient ways to regulate the duck kill” (Bellrose 1944:371). The most desirable dates for waterfowl hunt- ing seasons of various lengths in Illinois were determined (Bellrose 1944:371): For a 30-day season, November 1-30; for a 45-day season, October 22—December 5; for a 60-day season, October 10-—December 8; for a 70-day season, October 1-December 9; for an 80-day season, September 26—December 14; for a 100-day season, September 20- December 28. A study of flyway refuges in Illinois (Bellrose 1954:169) led to the conclu- sion that they were of value both to waterfowl and to hunters. Flyway refuges permitted waterfowl to rest along the flyway during the hunting season and placed more food within their reach, thereby conserving food resources on the wintering grounds. Waterfowl concen- trating on the refuges fed in fields and marshes within their daily cruising range. Thus, the refuges provided for holding local concentrations of ducks which could be shot when they flew out to feed. One of the most impressive duck flights in a decade swept through Illinois on November 2, 1955 (Bellrose 1957). It was determined that most of the birds in the flight left Canada on November 1 and moved so rapidly that some reached the Gulf of Mexico by the morning of November 3. This mass migration of waterfowl was evaluated by Bellrose (1957:24) as follows: Low pressure areas in Canada resulted in a southward flow of a mass of Continental Arctic air. The low temperatures resulting from Continental Arctic air triggered the flight from the Great Plains of Canada and the United States. Over 75,000 ducks, largely mallards, have been banded by Natural History Survey investigators at four widely sepa- rated localities in the state. Recoveries from some of the bandings were used in calculating the annual mortality of the mallard, black duck, and _ blue-winged teal (Bellrose & Chase 1950). Of the three species, the mallard proved to have the lowest mortality rate, and_ this “amounted to 55 out of 100 birds the 194 Ittinois NaturAL History SurvEY BULLETIN first year, or year of banding, 20 the sec- ond year, 11 the third year, and 6 the fourth year” (Bellrose & Chase 1950: 25). The banding data have also been used to delineate the migration routes of ducks passing through Illinois. As part of an effort to evaluate losses from crippling by hunters, several thou- sand ducks were trapped and fluoroscoped for shot pellets and broken bones. Among apparently healthy mallards, 36.4 per . cent of the adult drakes, 18.0 per cent of the juvenile drakes, and 21.4 per cent of the hens were carrying one or more shot pellets imbedded in flesh or internal organs (Bellrose 1953b:344). “Of the ducks . . . knocked down by hunters, as reported from various sections of the United States, 22.5 per cent were not retrieved’ (Bellrose 19535:357). A spectacular die-off of mallard ducks near Grafton in January, 1947, prompted a joint investigation by the Natural History Survey and the United States Fish and Wildlife Service [now U. S. Bureau of Sport Fisheries and Wildlife]. A still greater die-off in the same area a year later attracted the attention of officials of the Western Cartridge Com- pany of East Alton. As an outgrowth of the situation, a co-operative investigation of lead poisoning in waterfowl was begun in July, 1948, by the Illinois Natural History Survey, the Western Cartridge Company, which is a Division of the Olin Industries, Inc. [now Olin Mathieson Chemical Corpora- tion], and the University of Illinois (Jordan & Bellrose 1951:3-4). Although Lubaloy shot and _ several lead alloys were tested as substitutes for commercial lead shot, none showed prom- ise in alleviating lead poisoning in water- fowl (Jordan & Bellrose 1950:167-8). It was estimated by Bellrose (1959) that each year approximately 4 per cent of the mallards of the Mississippi Flyway die from lead poisoning and that an addi- tional 1 per cent are afflicted with lead poisoning but are bagged by hunters. Al- though several other species of ducks in- gested larger numbers of shot per bird than did the mallard, the mallard suffered the highest rate of loss. Mortality from lead poisoning proved to be greater among ducks of the Mississippi Flyway than among those of other flyways. The use of iron shot as a substitute for lead shot was suggested as a possible means of con- tending with the lead poisoning problem Vol. 27, Art. 2 in the event drastic measures should be- come necessary. The means by which ducks find their way from their breeding to wintering grounds has been under investigation. Juvenile blue-winged teals were captured in migration in Illinois and held in cap- tivity until all the other blue-winged teals had migrated south of the United States (Bellrose 19582). They were then banded and released. From _ recoveries of bands it was found that these juveniles, though unfamiliar with the route, flew southward along lines of flight similar to those of adults. Experiments with wild mallards demonstrated an ability to orient by celestial means (Bellrose 1958d). The initial flight of mallards released in unfamiliar areas was northward on clear days or nights and in apparently random directions when skies were cloudy and sun and stars were obscured. The Mourning Dove.—The mourn- ing dove became the subject of an in- tensive research effort in the autumn of 1948 when it was seen that data were needed for an objective evaluation of claims that doves were being shot to ex- tinction by hunters in Illinois. The kill of doves in 1946 and 1947 was estimated from hunter reports to have been 200,000 in each year and about 300,000 in 1949 (Hanson & Kossack 1950:31). It was later determined that the kill was fairly evenly distributed over the state (Mar- quardt & Scott 1952). A program of dove banding, particu- larly of nestlings, was undertaken to de- termine points of origin of populations. Banding by amateur co-operators was en- couraged (Kossack 1955), and a _ tech- nique employing elastic adhesive tape to secure bands on small nestlings was de- veloped (Kossack 1952). ‘These aspects of the program were later adopted on a country-wide scale by the U. S. Bureau of Sport Fisheries and Wildlife. A portable candler was constructed for aging dove eggs in the field (Hanson 1954). Photographic and _ descriptive guides for aging incubated eggs and nestlings were prepared (Hanson & Kos- sack 1957a). The predominance of uni- sexual broods in mourning doves was found in early studies (Kossack & Han- son 1953). This subject is being treated December, 1958 ScoTT: in greater detail in a report, now in preparation, on sex ratios in doves. The effort to appraise mortality among mourning doves included study of their parasites and diseases (Kossack & Han- son 1954; Levine 1954; Hanson, Levine, Kossack, Kantor, & Stannard 1957). The paper by Hanson ef al. describes the ectoparasites of doves and the arthropod fauna of their nests and summarizes the results of a 7-year study of the incidence of blood parasites in relation to ages of the doves and to regions of the state. The relation of age and the stages of wing molt to body weight, body fat, and migration habits was studied (Hanson & Kossack 19574). In contrast to interpre- tations of fat deposition in passerines, the analysis of data on fat deposition in mourning doves showed no consistent re- lationship to migratory habits, but instead proved to be related to the energy de- mands of the molt, regional farming prac- tices, soil fertility, and food habits. Doves that had fed almost exclusively on corn in good soil areas had formed relatively heavy amounts of fat; most of those taken on poor, sandy soil where they fed largely on seeds of wild plants had formed little or no fat. After 10 years of study there is still no evidence that dove populations in IIli- nois are controlled by hunting. Popula- tion declines which have taken place are generally traceable to habitat destruction, disease, and adverse weather. Mammals To the wildlife historian the apparent lack of interest in mammals by early re- searchers of the Natural History Survey and its predecessors constitutes something of an enigma. Almost half a century slipped away before Forbes, upon receiv- ing a letter from C. A. Rowe of Jackson- ville in April of 1907 reporting the de- struction of seed corn by moles and en- closing the stomach contents of a mole containing about 65 per cent corn, was stimulated to authorize research on a problem in economic mammalogy (West 1910:14). The resulting studies (Wood 19106; West 1910) provided the first evi- dence that moles included corn, or any substantial amount of plant food, for that matter, in their diet. WILDLIFE RESEARCH 195 Fur-Bearing Mammals.—Forbes (19124) included fur-bearing mammals among the animal resources of Illinois, but a program of consequence did not get under way until the 1930’s, when evaluations of fur resources were under- taken. Neither technical nor popular interest was great enough to focus further attention of the state’s research agencies on furbearers until, in 1930, David H. Thompson, E. C. Driver, and D. I. Rasmussen of the Illinois Natural History Survey staff borrowed trap- pers’ reports... from the Illinois State De- partment of Conservation, to which law provided that each licensed trapper report his catch monthly during the trapping season (Mohr 1943a:505). Brown & Yeager (1943:437) stated that some of the figures derived by Driver and Rasmussen were published in the Blue Book of the State of Illinois (Frison 1931, 1933). Following a limited survey of helminth parasites in fur-bearing animals collected during the hunting seasons of 1935-36 and 1936-37, Leigh (1940:191) stated that “A study of the literature offers lit- tle information on pathogenicity of the parasites found in the hosts studied.’ This shortcoming in our knowledge con- tinues to prevail. The desire to obtain a reasonably re- liable evaluation of the fur resource in Illinois eventually resulted in two im- pressive reports (Brown & Yeager 1943; Mohr 1943a). Brown & Yeager (1943) based their evaluation on an intensive oral survey covering the 1938-39 and 1939-40 trapping seasons, and Mohr (1943a) made an analysis of fur-taker re- ports beginning with the 1929-30 trap- ping season and ending with that of 1939-40, excepting the 1931-32, 1932- 33, and 1933-34 seasons. The results obtained by the two methods were rela- tively similar. The average value of the annual fur catch was estimated to have been a little over $1,000,000, about 80 per cent of which represented returns for muskrats and minks. To aid in investiga- tion of fur-bearing animals, Yeager (1941a) assembled a bibliography of over 2,600 references on North American fur animals. Some valuable contributions on the relationship of muskrat populations to 196 I-tinois NATuRAL History SurvEY BULLETIN fluctuating water levels in bottomland lakes flanking the Illinois River have been made by Natural History Survey re- searchers. Bellrose & Brown (1941 :207) observed that the numbers of muskrat houses were nearly six times as many in lakes with a stable, as in those with a semistable, water level and there were twice as many lodges per acre in lakes with a semistable, as in those with a fluctuating, water level. Stable water levels favored the growth of those species of aquatic plants most desirable for muskrats. Later, following an investigation of the response of musk- rat populations to flood and low water levels in these bottomland lakes, Bellrose & Low (1943:187) concluded: While muskrats may be harassed and deci- mated within a short time during flood con- ditions, those living under low water condi- tions may escape without serious loss in summer but may be seriously affected during cold, winter weather. In 1940-41 and 1943-44 Bellrose 1950) developed a new technique for evaluating the food preferences of musk- rats by comparing the proportions of plant foods taken from “feeding” lodges in mid- winter with the proportions of plants known to have been within the feeding range of the muskrats. Cattail was rated the most preferred food. The capacity of vegetative types to support muskrat popu- lations was determined by recording the density of muskrat lodges in each vegeta- tion type. River bulrush and cattail had the greatest population values. Advantage was taken of two unusually fine opportunities for measuring the re- sponse of raccoons to a food windfall of ducks (Yeager & Rennels 1943) and geese (Yeager & Elder 1945) made avail- able as hunters’ crippling losses at the Pere Marquette Wildlife Experimental Area immediately above the confluence of the Illinois and Mississippi rivers and at the Horseshoe Lake Game Refuge in Alexander County. At the Horseshoe Lake Game Refuge, where crippling losses were alarmingly high, bird remains, chiefly those of Canada geese, occurred in 20.7 per cent of the raccoon droppings collected a day after the hunting season opened and in 87.9 per cent of the drop- pings collected 3 weeks after the close of Vol. 27, Art. 2 the season (Yeager & Elder 1945:49- 51). In 1939 and 1940, on the Pere Marquette Wildlife Experimental Area, duck remains did not occur in raccoon droppings collected before the opening of the waterfowl season, but after opening of the season “remains of mallard, pin- tail, and wood duck were 89 per cent of the bird material in 1939, and 76 per cent in 1940” (Yeager & Rennels 1943:59). These findings indicate that crippled waterfowl may not constitute a complete loss, inasmuch as furbearers utilize them as food. The biology of the raccoon is currently under intensive study by Glen C. Sanderson. A survey of the population and distri- bution of beavers in Illinois was con- ducted under a co-operative Federal Aid project from April 1, 1947, through June 30, 1951. It was found (Pietsch 1957: 193-6) that beavers were “last reported” in Illinois in 1912, were reintroduced in 1929, were estimated to number 3,565 in 45 counties in 1950, and were reported from 55 counties in 1954. The red fox was made the subject of a thorough evaluation (Scott 1955) be- cause the values of this colorful mammal were believed to have been regularly underrated. This evaluation was based on personal experience extending over 20 years and a number of intensive investi- gations (Scott 1943, 1947; Scott & Klim- stra 1955) especially relating to the red fox as a predator. As a result of this evaluation, Scott’ (1955:14) recom- mended: 1. The encouragement of an increased use of red foxes for sport hunting, . . 2. The education of those who hope for increased small game populations through fox extermination campaigns to the more con- crete and lasting results that may be expected from habitat improvement programs... . 3. The elimination of bounty payments on red foxes. 4. The enactment and enforcement of more effective antirabies laws, especially as ap- plied to the compulsory vaccination and quarantine of domestic dogs, and prompt re- duction by organized trapping of red fox populations in which rabies epizootics occur. 5. The increased attention by game man- agers to the proper management of the red fox resource in general, including assistance with the cropping of surplus animals in areas where adequate cropping has not been ac- complished by hunters. December, 1958 Game Mammals.—tThe cottontail rabbit tops the list of game mammals in Illinois in a number of respects. In a survey of license-stub kill cards for the 1950-51 hunting season, Marquardt & Scott (1952:4) found that rabbits pro- vided twice as many sportsmen with game in the bag as did any other game species and numbered more than twice as many as any other kind of game animal re- ported. Rabbits constitute the chief game animal of the state largely because they are widely distributed and because they possess the reproductive potential to main- tain themselves despite high mortality, in- cluding that from severe hunting pressure. Proving that there is some bad with the good, however, is the fact that tula- remia, a disease which is transmissible to man, occurs in rabbits. “In the period 1926-1949, Illinois had more than 3,000 reported cases of human tularemia, about twice as many as any of the other states” (Yeatter & Thompson 1952:351). Yeat- ter & Thompson (1952:379) reported that “The human tularemia rate in any year in Illinois seems to be determined both by temperatures about the time of the open- ing of the rabbit season and by the abundance of rabbits.’ They concluded that the incidence of human tularemia in Illinois could be reduced by delaying the opening of the rabbit hunting season until about December 1. As a result of these findings, the opening of the hunting sea- son in Illinois was postponed until No- vember 26 in 1955. In recent years meth- ods of treating tularemia in humans have been greatly simplified by the use of anti- biotics. It seems certain, however, that most hunters will prefer not to depend upon antibiotics—that they will enjoy their rabbit hunting far more knowing that by hunting within a season which opens after the onset of sharp freezing weather they and their families are ex- posed to the hazard of tularemia only to a minimum extent. Yeatter & Thompson (1952:378) recommended, as a refinement to their studies, further study of ticks, other tula- remia vectors, and the biology of the rabbit. Ecke (1955:294-6) recorded a complete description of the courtship and mating of cottontails. Also, Ecke (1955: 305) found evidence which suggested Scott: WILDLIFE RESEARCH 197 “that some component of green vegeta- tion, possibly Vitamin E, is responsible for stimulating the pituitary glands of rabbits into the secretion of somatic nutri- tives, and consequently, determining the breeding conditions of the animals.” Dr. Rexford D. Lord (1958:274) has recently constructed life tables which indicate that as many as 24 to 27 per cent of the rabbits available to hunters in autumn may be the young of rabbits born in the spring of the same year. Ecke & Yeatter (1956:212-3) at- tributed the death of a rabbit, estimated to have been about 13 days of age, to coccidiosis and suggested further study of coccidiosis as a cause of mortality among rabbits. Detailed studies of ectoparasites of rabbits have been carried on since 1952 by Dr. Lewis J. Stannard, Lysle R. Pietsch;.Dr. Carlb.Os Mohr, and «Dr. Lord. The realization that tradition for a summer hunting season on squirrels in Illinois was not biologically sound touched off a thorough investigation (Brown & Yeager 1945) of fox squirrels and gray squirrels in 1940. The chief objection to a summer hunting season was that it re- sulted in the killing of pregnant and lac- tating females. Brown & Yeager (1945: 526) estimated that summer hunting re- sulted in a wasteful loss of 31.8 unborn and suckling squirrels for each 100 squir- rels bagged. Because the tradition for summer hunting was strong and because squirrel hunting was good in some parts of the state despite early hunting seasons in the past, Brown & Yeager (1945: 526-8) believed it unwise to enact a sea- son beginning so late that it would pre- vent all losses resulting from the killing of pregnant and lactating females and they observed: “Such a season could hard- ly begin earlier than October 1, and it would certainly be opposed by a large number of hunters.’ A compromise sea- son of September 15 to November 15 in central and northern I]linois and Septem- ber 1 to October 31 in southern Illinois was recommended. This recommendation has not been accepted by Illinois hunt- ers. The report by Pietsch (1954) on deer populations in Illinois will be of especial value to the future wildlife historian, 198 Pietsch reported upon the early history of the deer in Illinois, recent populations, and management. Hunting was suggested as'a means of control, and the deer sea- son, after being closed for 56 years, was opened in 1957 for hunting with bows and shotguns. Miscellaneous Contributions to Mammalogy.— Mohr (19434, 1947a) appraised population data for small mam- mals in North America. He calculated ~ the weight of specific populations within the area occupied and concluded that population densities within groups of mammals having similar feeding habits were limited by the size of the mammal concerned. Also, Mohr (19474) recorded miscellaneous data on populations of cer- tain mammals in Illinois for future refer- ence. On December 1, 1956, a grant-in-aid was made by the National Institutes of Health of the U. S. Public Health Serv- ice to initiate a 3-year study of epizootiol- ogy of rabies in wild mammals. This in- vestigation is aimed at identification of the key hosts to rabies in Illinois and those factors that make them key hosts. WILDLIFE MANAGEMENT “Applied programs in the field of bio- logical science are seldom, if ever, de- veloped without the aid of years of pa- tient, so-called unapplied, researches” (Frison 19424:5). Frison believed that sufficient basic knowledge had been ac- cumulated to support applied manage- ment programs of an exploratory nature, and, with characteristic vigor, he encour- aged work of this kind in the late 1930's. Later, he insisted that these programs be evaluated for monetary return, wildlife yield, and other benefits. Two of these early programs concerned management of upland wildlife in central and northern Illinois. One of the first attempts to develop wildlife habitat on intensively cultivated land took place on the Urbana Township Wildlife Area, which was believed “typical of the best Illinois cornbelt farmland” (Hessel- schwerdt 1942:31). Habitat develop- ment was begun on this area in 1937, and in 1939 the project came under the Federal Aid program. Development fea- Ittinois NATURAL History SurvEY BULLETIN Vol. 27, Art. 2 tures included fencerow plantings, instal- lation of den boxes, block planting, and protection of strips along drainage ditches. Usage of the den boxes was evaluated. Fox squirrels appeared to extend their range and to increase in numbers as a result of the provision of den boxes (Hesselschwerdt 1942:33-4, 36). Usable den boxes are no longer present on the area, and resident fox squirrels are un- common. As the fencerow plantings ma- tured, cottontail rabbits and songbirds in- creased in numbers (Wandell 1948 :262- 3), but populations of pheasants and quail have shown no appreciable increase. Minks and muskrats trapped along an un- grazed section of a drainage ditch in 1944-45 provided an estimated per-acre income of $62.78, more than 10 times that produced by the same ditch where it was heavily grazed (Yeager 1945:85). On October 1, 1939, a Federal Aid project to determine the availability of land for wildlife habitat on the inten- sively cultivated farm land of the Illinois dark prairie was initiated (Spooner & Yeager 1942). Land for refuges and cover development was found to be avail- able, without purchase, in small scat- tered tracts, and obtainable through long- term easements. Spooner & Yeager (1942: 54) concluded that “Although the proj- ect shows promise of wide application on the Illinois prairie, there are yet many problems which must be further an- alyzed before its entire success is proved.” Natural History Survey staff members have participated in various other pro- grams closely related to management of upland wildlife. The Survey sponsored the initial acquisition in 1940, by the Department of Conservation, of a tract of sand prairie and wet land in Lee Coun- ty, the Green River Area, as a manage- ment area for prairie chickens, water- fowl, and other animals. It is believed that this tract of land has played an im- portant part in maintaining the only siz- able flock of prairie chickens surviving in northern Illinois. However, unless the area is managed with primary considera- tion for the original objectives, it may well go down in history as the place where native prairie chickens met their end in northern Illinois. Frank C. Bell- rose proposed the purchase of the Rice -“ a December, 1958 SCOTT : Lake Wildlife Area by the state in 1942, and the area, now the best duck area in the state, was purchased by the Illinois Department of Conservation in 1943. In 1955 a Federal Aid research proj- ect was initiated by Southern Illinois University, the Illinois Department of Conservation, and the Illinois Natural History Survey to determine the economic values and benefit to wildlife of wide- row culture of corn in southern Illinois. Potential benefits, to the farmer, of wide- row culture and interplanting with cover crops included conservation of soil, in- crease of fertility, elimination of the low- paying oat crop in rotations, saving of labor, and yields of corn comparable to those from conventional cultural methods (Vohs 1957). The extent of use of wide-row corn- fields by wildlife varied with the at- tractiveness of the interseeding. How- ever, comparable observations on the numbers of wildlife in wide-row fields and standard interval fields revealed ra- tios of 5 to 1 for bobwhite quail, 12 to 1 for mourning doves, and 6 to | for cot- tontail rabbits. Wide-row corn is con- sidered to have great potential for wild- life management especially, because it provides for an increase in wildlife values in thousands of acres of corn. Evaluations of wildlife populations and possibilities for their management were made on marginal lands. Analyses were made of possibilities for management of coal-stripped land for the benefit of up- land game and furbearers (Yeager 1941), 1942), management of agricultural drain- age systems for production of furbearers (Yeager 1943), and yields of fur from animals produced on different types of land (Yeager 1945). Another project concerned the use of hunting dogs in sport and conservation (Yeatter 1948). Levee and drainage districts have re- duced the flood plain along the Illinois River by almost half, about 200,000 acres. In view of the resulting loss of recreational opportunities and the in- creased danger from floods, Bellrose (1945) made a survey of the relative values of drained and undrained bottom- lands. Later, Bellrose & Rollings (1949) calculated the annual per-acre value, to the public and to owners, of bottomland WILDLIFE RESEARCH 199 lakes of the Illinois River valley. They concluded that bottomland lakes in the Illinois River valley had an annual per- acre value to the public, 1944-1947, of $26.35, made up as follows: duck hunting $12.18, angling $2.40, commercial fishing $9.65, and fur trapping $2.12; they esti- mated that privately owned lakes were capable of producing an average yearly gross return to owners of $18.57 per acre (Bellrose & Rollings 1949:23). Following an investigation of the ef- fects of flooding on mammals in and around a bottomland lake in the Illinois River valley, Yeager & Anderson (1944: 178) concluded that ‘The effect of flood- ing on mammals ranged from heavy mortality in the case of woodchucks to apparently little basic change in the be- havior of minks.” For various kinds of fur-bearing and game mammals, Yeager (1949) recorded the changes in abun- dance caused by permanent flooding of wooded bottomland over an 8-year pe- riod, 1939-1946. The site was a tract of 600 acres in the junction of the Mis- sissippi and Illinois rivers; the area was flooded in 1938 by closing of the gates of the then new Alton dam. THE FUTURE Because the wildlife resource and the environment essential to its existence have economic and recreational values beyond general public appreciation and because knowledge on which to base in- telligent management of this resource is in the best interest of the people of I[]li- nois, I believe that we must plan for the future of wildlife research in Illinois as a part of our evaluation of the past. Forbes (1907c:892) expressed view when he wrote this that we are... practically interested in what has come and gone only as it may help us to bring a new thing into being in a way to se- cure its permanent continuance and its normal growth. In the past the wildlife research pro- gram of the Illinois Natural History Survey has been heavily weighted toward investigations of migratory game birds. These investigations have been extremely valuable and must be continued in the 200 future; however, increasing attention must be given to other wild species, in- cluding nongame species. Nongame spe- cies must be studied not only because they represent economic and _ esthetic values but also because some of them, such as mice, are especially useful in basic research. Responsibility for research on certain species cannot be side-stepped on the ground that effective study of these species is being carried on in other states, for Illinois has problems characteristic of its own land-use pattern and it bears a responsibility to other states inasmuch as enlightenment on particular problems is often best obtained through comparison of range-wide differences. While it is true that great progress has been made in wildlife research, and the number of unknowns has been re- duced, this increased knowledge has ex- panded our awareness of unknowns. Many research techniques have been de- veloped, but, in most instances, the de- gree of their reliability has not been adequately determined, and refinement is desirable. Although the research has been increasingly objective, it must be ad- mitted that there is need for improve- ment. The expanding field of wildlife research requires specialization, but it also requires integration and synthesis. This post-mortem of wildlife research impresses me with the fact that the qual- ity of a contribution is influenced not only by the capabilities of the individual researcher but also by the length of time devoted to concentrated effort on par- ticular problems. If real progress is to be realized in the future, the sustained and concentrated effort of top-flight re- searchers must be insured. Illinois will stand among the leaders in wildlife re- search only so long as the means with which to attract and hold qualified per- sonnel for extended periods is provided. Provisions must be made for long-range research, with monographic-type publica- tion being an objective. And, finally, we must guard against becoming desk- and laboratory-bound theorists and interpret- ers. It is essential that contact be main- tained with living organisms in their nat- ural surroundings. Much of our research effort has moved in the direction of life history, ecology, ILtinois NAruRAL History Survey BULLETIN Vol. 27, Art. 2 and populations. And much of it must continue to move in this direction. How- ever, means for improvement must be constantly sought out. In life history studies, we must be increasingly objec- tive. In ecology, we must be mindful of the need for land-use practices which are compatible with the best interests of both landowners and _ wildlife, especially in view of the increasing use of marginal -land and agricultural chemicals. In the area of population mechanics, we must not only measure population trends and population composition; we must also seek and evaluate with greater refinement those factors which influence population trends and make-up. In the future more attention must be given to fields of study only lightly touched upon in the past. Animal be- havior, a vital and challenging field, must be explored particularly, for what an ani- mal does is more important to the wild- life manager than what it is. Mobility, especially migration, must be examined more critically. Nutrition, qualitative as well as quantitative, must be investigated, and techniques for evaluating “condition” in wildlife must be explored. Anatomy, embryology, genetics, physiology, and biochemistry must, of necessity, play a larger part in the evaluations of the future. We must guard against the neglect or shunning of certain research by avoiding a “that’s been done before’ philosophy. It may well have been done before, but we must be careful to evaluate the thoroughness with which it was done. We must examine it for weaknesses and for its value as a basis for new working hypotheses. The wildlife research of the Natural History Survey has been instrumental in bringing about desirable changes in estab- lished policies and practices and in the establishment of new policies and prac- tices which affect wildlife. We must pro- vide adequate bases for the policy making of the future. To these ends we must move in the direction of prompt publica- tion, and we must make certain that use- ful publicity is given especially to those findings which indicate that support of, or changes in, practices or administrative policies are desirable. Oe ee ee ee ee ee ee ee ee ee ee ee ‘al ~ =i bao December, 1958 Scorr: Our thinking must be projected far into the future in an effort to visualize those areas where knowledge will be most needed. Anticipating the future is ad- mittedly fraught with pitfalls. It seems certain, however, that human populations will continue to increase in Illinois. This increase will be attended by more inten- sive use of land and water, more exten- sive transportation and communication systems, more extensive residential and industrial areas, more exhaustive use of fuels and metals, greater use of atomic energy, more automation, and more lei- sure time. From the wildlife manager’s point of view, this condition forewarns of an in- creasingly severe competition between wildlife and basic human needs. When it is considered that wildlife must be pro- duced primarily on lands utilized for other purposes, the problems of the fu- ture for wildlife become obvious. The in- creasing demand for human food will make it essential that harvest methods be refined to reduce waste, that more heavily yielding crops be developed, that more marginal land be brought into use, and that more agricultural chemicals be ap- plied. This promises not only to reduce wildlife populations but to force them below minimum survival levels, unless effective provisions, such as wide-row corn may prove to be, are constantly sought out by wildlife managers. The need for refuges to insure the survival of rare species will increase. The relative importance of those wild animals which compete with humans for food by eating or contaminating it will be magnified. Intensive use of water could create a WILDLIFE RESEARCH 201 pollution problem such as would virtually deny aquatic life outside protected areas, unless pollution control, including provi- sion for disposal of radioactive waste, keeps pace with increased water utiliza- tion. The provision of a means for satisfy- ing the psychological needs of a human population with more leisure time and relatively less elbow room comprises a formidable challenge. If the human pop- ulation is to maintain some semblance of sanity, services such as those offered by wildlife biology must be given equal recognition with those of the physical sciences. Perhaps the average family of the future will tend to satisfy more of its needs for pleasure in the out-of-doors and for escape from the pressures of civi- lization in its own backyard. Hence, the wildlife manager should contrive to know more about the management of the home landscape for wildlife. It seems certain that an increasing amount of hunting will take place on regulated shooting areas, that is, unless hunting proves to be good in outer space. The wildlife manager’s problems of the past, considerable as they have been, seem as child’s play compared with those looming in the future. The wildlife man- ager is going to need determination, cour- age, ability, compensation, and means such as never before. Perhaps we can ease some of his problems by the effective planning of current research to provide a sound basis for the essential decisions of the future. Indeed, wildlife manage- ment as a profession may well depend on the soundness of today’s plans for the future. Publications and Public Relations ANY of the men whose names were written large in the early annals of the Illinois Natural History Survey had been educated in the classical tradition. Most of the physicians, educators, and others whose formal schooling included college had undergone the discipline of Latin and Greek studies. Jonathan Baldwin Turner, elected first president of the Illinois Natural History Society in 1858 (Bateman 18584:258), was a graduate of Yale College and for many years Professor of Belles Lettres, Latin, and Greek at Illinois College, Jacksonville (Carriel 1911:12, 46). Charles E. Hovey, first secretary of the Society (Bateman 18584:258) and first head of the Illinois State Normal Uni- versity, was a graduate of Dartmouth College (Marshall 1956:28). Joseph Ad- dison Sewall, early curator, had studied at both Yale and Harvard and was a graduate of Harvard Medical College (Marshall 1956:78). Benjamin Dann Walsh, first State Entomologist, was a graduate of Trinity College of Cambridge University in Eng- land (Weiss 1936:234). William Le Baron, second State Entomologist, was, like Sewall, a graduate of Harvard Med- ical College (Goding 1885:122). Although Stephen Alfred Forbes, fourth State Entomologist, first and only Director of the State Laboratory of Nat- ural History, and first Chief of the Nat- ural History Survey, had comparatively little formal education as a youth, he had subjected himself to the discipline of lan- guage study. At home he had studied French and Spanish, and in Confederate prisons during the Civil War he had spent some of his “abundant leisure” in studying Greek from books he managed to buy at Mobile (Howard 1932:6). The early leaders in Illinois science, most of them classicists before they were scientists, had developed respect for the meaning and sound of words, and had ac- quired a skill in word usage that carried into their scientific writings. JAMES SS. Ae Trained in the classics though most of these leaders were, many were neverthe- less aware that classical education had limitations. They saw that in Illinois, in the middle of the nineteenth century, edu- cation must be brought out of ivied halls to the furrow and the work bench. In the Illinois College classroom Tur- ner was a teacher of Latin and Greek. Out of the classroom, he was a leader in the movement for industrial education, the education of the farmer and the me- chanic. Turner asked (Carriel 1911:76): But where are the universities, the appara- tus, the professors, and the literature spe- cifically adapted to any one of the industrial classes? . . . society has become, long since, wise enough to know that its teachers need to be educated; but it has not yet become wise enough to know that its workers need educa- tion just as much. Socrates, Cincinnatus, Washington, Franklin, and other worthies, Turner ar- gued, derived their education “from their connection with the practical pursuits of life” (Carriel 1911:117): What we want from schools is to teach men . .. to derive their mental and moral strength from their own pursuits, whatever they are, and to gather from other sources as much more as they find time to achieve. We wish to teach them to read books, only that they may the better read and understand the great volume of nature ever open before them. Can, then, no schools and no literature, suited to the peculiar wants of the industrial classes, be created by the application of science to their pursuits? Walsh (18684:9) emphasized that his annual report as Acting State Entomolo- gist was “intended chiefly for the use of common folks.” Writing as Editor of the only volume of Transactions published by the Natural History Society itself, C. D. Wilber (1861d:3-4) epitomized the educational movement of the time, a movement that might be termed a revolt of the classicists against the classical tradition: It has been the aim of the Editor, to present only such articles and papers as are immedi- ately useful and interesting to the citizens and [ 202 ] ee EOS ee pe a Le Se et st CO eG ee Rn OS ee et ae anes December, 1958 schools of Illinois, with a hope that a zeal for the pursuits and studies of Natural History may spring up among our people, like the seeds of the sower, in the parable, falling upon good soil, and yielding, ‘some sixty and some an hundred fold.” In order to render the greatest good to all, the subjects have generally been treated in a popular rather than a technical style. It has been said, that he who places a valuable truth or fact within the reach of the million, is doing more for humanity than he who discovers it. And, indeed, if scientific men, or libraries and museums, cannot contribute to the elevation of the masses who are less privileged, their use- fulness is questionable. The ideas reflected in TTurner’s ques- tions and answers and in Wilber’s com- ments culminated in the Morrill Act of 1862, in land grant colleges, and, spe- cifically, in the Illinois Industrial Uni- versity at Urbana. Both cause and effect of the movement for general education was the increasing thirst that Illinois people in the middle of the nineteenth century had for knowledge, the growing conviction that information should be widely disseminated. “—The movement led to the formation of, and was abetted by, the Illinois State Horticultural Society, the Illinois State Agricultural Society, and the Illinois Natural History Society. The Natural History Society was not an accident nor an isolated segment of history. It was part of a contagious movement sweeping the prairies. As seen by Wilber (1861d:7): The demand for this movement seemed to proceed from a want of accurate knowledge in nearly all departments of Natural History in the State; and also, from a desire that all facts and discoveries in a field so vast as Illinois, should be made immediately subservient to the great ends of popular education. EARLY PUBLICATIONS The Illinois scientist in mid-nineteenth century looking for means of disseminat- ing knowledge had few publication out- lets. Among the small number of scien- tific journals published before 1860 were The American Journal of Science, found- ed in 1818, the Entomologist of London, in 1840, and the Boston Journal of Nat- ural History, in 1834. The first Trans- actions of the Illinois State Agricultural Society were published in 1855; the first Transactions published by the Illinois AYARS: PUBLICATIONS AND PUBLIC RELATIONS 203 State Horticultural Society itself were dated 1863. The first Proceedings of the Entomological Society of Philadelphia were published in 1861. The American Naturalist was not founded until 1867, the Botanical Gazette not until 1875. The Prairie Farmer had been estab- lished at Chicago in 1841, and to this pe- riodical, frankly slanted toward the in- terests of practical farmers, Illinois sci- entists of mid-century turned for publica- tion of their technical papers. The pub- lication by Prairie Farmer of many of these papers, some significant enough to attract the attention of eminent scientists in other parts of the country, is indication of the extent to which the classicists and the industrialists had become wedded. That publication of scientific papers was an important aim of the founders of the Illinois Natural History Society is evident from written records of the or- ganization. The object of the Society, as outlined by Cyrus Thomas in his letter read before Illinois teachers meeting in Decatur, December 29, 1857 (Bateman 1858a:12), shall be the investigation and study of the Flora, Fauna, Geology, and Mineralogy of Illinois, and the illustration of the same by gathering specimens, exchanging the same, and by publishing such meritorious works thereon as the authors may present, ... At the last session of its second meet- ing, held on June 20 and 21, 1859, at Bloomington, the Society (Francis 1859 :664) resolved that “the Execu- tive Committee be required to procure the publication of the papers and proceed- ings of the Society in some paper gener- ally circulated through the State.” The Executive Committee in turn resolved that, ‘in accordance with the resolution of the Society, we select THE PRAIRIE FARMER as its medium for publishing the papers and proceedings of the Society.” Another outlet for papers written by members of the Natural History Society was provided by the [llinois State Agri- cultural Society. In its own published Transactions the Agricultural Society in- cluded the V'ransactions of the first three meetings of the Natural History Society and several papers contributed by mem- bers (Francis 1859a, 18595, Wilber 1861a). 204 In 1861 the Natural History Society itself published what it termed the ‘‘Sec- ond Edition” of Volume I, Series I, of its Transactions (Wilber 1861d). Most of the material in this volume had been printed previously by the Agricultural Society in its Transactions for 1857-1858 (Wilber 1861a). Wilber’s Preface to the volume published by the Natural History Society was dated October 30, 1861 (Wilber 1861d:4). The Civil War had begun 6 months before. In 1867, after the War was over and men again had time to consider civilian science, the state legislature in a single session made an appropriation to the I[Ili- nois Natural History Society, provided for a State Entomologist, and authorized establishment of the Illinois Industrial University (Illinois General Assembly 1867). The legislative act that provided for a State Entomologist required him to pre- pare “a report of his researches and dis- coveries in entomology for publication by the state, annually” (Illinois General As- sembly 1867:36). The act of 1867 in which state appro- priations were first made to the Illinois Natural History Society and the act of 10 years later establishing the Illinois State Laboratory of Natural History made no mention of publications (Illinois General Assembly 1867:21-2; 1877: 14-6). In 1879, however, the state leg- islature appropriated to the State Lab- oratory for ‘“‘publication of bulletins, the sum of two hundred and fifty dollars per annum” (Illinois General Assembly 1879:42). An act approved June 27, 1885, a few months after Forbes had moved to Ur- bana, was specific about publication. It stipulated that the Director of the State Laboratory “shall present for publica- tion, from time to time, a series of sys- tematic reports covering the entire field of the zodlogy and the cryptogamic botany of Illinois.” The act appropriated ‘for the publication of bulletins, the sum of three hundred dollars per annum, and for the preparation and publication of the second volume of the report upon the zodlogy of the State, the sum of fifteen hundred dollars per annum”’ (Illinois General As- sembly 1885 :23-4). ItLinois NaturAL History SurvEY BULLETIN Vol. 27, Art. 2 The following year, Forbes staged an intellectual sit-down strike over a_pro- posed publication. Insufficient funds and conflicting legalities would not permit him to include what he considered suit- able illustrations in the State Entomolo- gist’s report he had prepared for publica- tion in 1886. Forbes (1886a:3) explained the situa- tion in the preface to a group of articles that he and members of his staff had writ- ten and that he had submitted to the State Board of Agriculture for publica- tion in its Transactions: A recent opinion of the Attorney General makes it doubtful whether the State Entomolo- gist of Illinois has the right, under the laws referring to that office (to some extent incon- sistent and conflicting), to prepare any other than a biennial report; and a change in prac- tice of the State Board of Contracts leaves no doubt whatever that a report published this year could not be illustrated. As an elaborate monograph of insects injurious to Indian corn was intended as the principal part of my ento- mological report for 1885, and as this article certainly should not be published without a large number of excellent figures, I have de- cided, under existing circumstances, not only to withhold this paper, but also to refrain from presenting any formal report for 1885, leaving it to the State Legislature to provide for the proper illustration of the reports hereafter, and to remove the present inconsistencies of the law. Unwilling, however, that the work of the office of the past year should be without repre- sentation in the Transactions of the State Board of Agriculture, with which the ento- mological report has been annually published for the last ten years, I have submitted to the Board, at the request of its Secretary, C. F. Mills, Esq., the following miscellaneous essays on economic entomology, summarizing the re- sults of such part of our operations as may well be published without cuts. At its next session the Illinois Gen- eral Assembly (1887:72) appropriated to the State Laboratory of Natural History $300 for publication of Laboratory bul- letins and $500 for “the illustration of the biennial report of the State Entomol- ogist.” In these days of high cost of printing, engraving, and other services, such sums as $300 and $500 seem insignificant. In 1887, however, they bulked large enough to help confirm in the public mind the importance of publication and _ illustra- tion in scientific research. In a biennial report issued about 3 years after assuming his duties in Urbana, 2. oe 7 December, 1958 Forbes (1888:7) described in detail the publications that were being issued under his direction: Our regular publications run in four series, two from the Laboratory and two from the Office of the State Entomologist,—the former comprising the State zoological report and the bulletins of the State Laboratory of Natural History, and the latter the biennial entomolog- ical report and the bulletins of the entomolog- ical office. During the past two years we have finished the printing of the first volume on the zoology of the State,—containing five hundred and twenty pages of text and forty-six plates,— devoted to the ornithology of Illinois as far as the water birds. This is a reprint of the vol- ume, the first edition having been entirely de- stroyed in the burning of the office of the State Printer last February. PUBLICATIONS SERIES The words “Volume I, Series I,” at the top of the title page of the only Trans- actions published by the Illinois Natural History Society under its own name are evidence that the members looked for- ward hopefully to continued publication. The date at the bottom of the page, 1861, and a glance at American history give testimony to the role the Civil War played in the Society’s annals. In 186] Charles Hovey, first secretary of the So- ciety and head of Illinois State Normal University, marched off to war as Colonel of the Schoolmaster’s Regiment, taking with him most of the men of the student body and some of the faculty (Marshall 1956:75-6). No one knows how many potential scientists died at Fort Donelson and in other engagements, or how much brain power from Illinois centers of learn- ing was siphoned from the science of peace into the science of war. Two years after the Civil War was over, biological science in Illinois re- sumed its march, but the Natural His- tory Society limped badly. It never re- covered from the effects of the conflict. However, in voting an appropriation to the Natural History Society and estab- lishing the State Entomologist’s Office and the Illinois Industrial University, the Illinois General Assembly (1867) gave substantial evidence that the people of the state wanted to continue the educational movement that founders of the Society had helped to start. AYARS: PUBLICATIONS AND PUBLIC RELATIONS 205 Walsh’s first and only report as State Entomologist was followed by the re- ports of his successors: 4 by William Le Baron, 6 by Cyrus Thomas, and 18 by Forbes. Le Baron (1871) named his first report the first report of the State Ento- mologist. The reports were discontinued when the State Entomologist’s Office was merged with the Illinois State Labora- tory of Natural History in 1917. In 1876, about 4 years after his appoint- ment as Curator of the Illinois Museum of Natural History, Forbes issued the first number of a technical series that has come down through the years as the Bul- letin. It has been known successively as the Bulletin of the Illinois Museum of Natural History, 1876; Bulletin of the State Laboratory of Natural History, 1877 to the end of June, 1917: Bulletin of the Illinois State Natural History Sur- vey, July, 1917, to early 1932; and I1linois Natural History Survey Bulletin, late 1932 to the present. Throughout its ex- istence the Bulletin has reported the re- sults of mature, original research. Most of the articles have been slanted toward technical workers in the biological sci- ences. Of wider interest are numbers of the circular series. The emphasis in this se- ries is on ““how-to-do’”—for example, how to control diseases or insect pests of shade trees. Directions in the circulars are based on the best available information and usually only to a limited extent on original research by the writers. The lan- guage of the circular series is less tech- nical than that of the Bulletin. The complete history of the circulars is not known. ‘‘We have also issued sev- eral entomological circulars not of any series,” Forbes (1888:7) wrote 70 years ago. ‘The modern circular series dates from 1918 and a 6-page unnumbered pub- lication titled ‘““The More Important In- secticides and Repellents,” by W. P. Flint. Between 1918 and 1930, 13 other circulars (3 unnumbered and 10 num- bered) were issued by the economic ento- mologists, 4+ by the foresters, and 1 by the botanist on the staff. Each circular was issued as a product of the section repre- sented by its author. In 1934 the circu- lar series was reorganized and the early circulars were numbered or renumbered. 206 The last circular published, I/linois Trees and Shrubs: Their Insect Enemies, 1s numbered 47. Some of the circulars have been reprinted more than once, one of them, that on insect collecting, five times. Diverse in several ways are the articles published in the Biological Notes series, {PG Prairies of Hlincis Insect Enemies A few of the circulars, articles of the Bulletin, Illinois Natural History Survey. the first of which was issued in Decem- ber, 1933, in mimeographed form. Some of the articles stand as progress reports of extensive projects, later to be subjects of articles in the Bulletin. Some are final reports covering small projects. Some are technical. Some emphasize “how-to-do”’ and in content and language are similar to the circulars. They are on various subjects and of various lengths. Early articles in this series were mimeographed and they contained no illustrations. Recent articles have contained illustrations and they have been planographed reproduc- ILtiInois NATruRAL History SuRVEY BULLETIN Vol. 27, Art. 2 tions of typewritten copy. The most re- cent article of the Biological Notes is No. 39. The fourth of the series of publications now issued by the Illinois Natural His- tory Survey is the manual. Each number is concerned with a single group of the EeTOPana: Sires SOrTONTAN ease i bee fla Norther nef A MECIACTL AR WATEEROWL MIGRATE Ie 4 CRNTRAL NORTH AMERICA j Fusarium Discase {8 Gladions: ity Catsal Avene ie i. | [_ HUUNOIS pees x Diseases and biological notes issued recently by the state flora or fauna, and each is designed for use by young as well as mature nat- uralists. The first of the manuals was Fieldbook of Illinois Wild Flowers. It was issued in 1936, is now out of print, and is being revised. Three other man- uals have been published, one on land snails, one on native shrubs, and one on mammals. Preceding the manual series in time, and somewhat similar in character, were the now discontinued final reports, two on birds and one on fishes (Ridgway 1889, 1895; Forbes & Richardson 1908). ss December, 1958 Other discontinued series were the Ex- ecutive Reports of the State Laboratory of Natural History, 1878-1916, and of the State Entomologist, 1900-1915. Most of these reports were published as pam- phlets and were published also in Univer- sity of Illinois reports or in Transactions of the State Horticultural Society. Annual reports made by the Natural History Survey to the Illinois State De- partment of Registration and Education were begun in 1918 and have been con- tinued to the present. hese reports have been published by the Division or by other administrative units of the state govern- ment. Biennial reports have for many years been included in the Blue Book of the State of Illinois. A considerable number of important contributions by Illinois Natural History Survey staff members have been published in the bulletin and circular series of the Illinois Agricultural Experiment Station. Many sstaff-written articles covering results of research have been published in technical journals. In a biennial report published 70 years ago, Forbes (1888:8) listed about a dozen articles “written at the Laboratory, but published elsewhere.” In each of the past few years, approxi- mately 80 articles written by staff mem- bers of the Illinois Natural History Sur- vey have appeared in publications other than those issued by the Survey. EDITORIAL PERSONNEL That some editing was done on the first papers published by the Illinois Nat- ural History Society is evident from a sentence in the Secretary’s Report pub- lished with the Transactions for 1860 (Wilber 1861d:8): “ The following pa- pers were prepared—most of them—for the last meeting of the Society, and have since been revised for publication in this report.” The Preface indicates that Wil- ber (1861d:3-4) was the Editor. For many years Forbes himself did considerable editing of the papers issued by the agencies he headed. Until 1926 his principal editorial assistants were Charles A. Hart and Miss Mary Jane Snyder. “Mr. C. A. Hart, my efficient secretary,” Forbes (1882a:8) wrote in an early report, “is responsible for the cor- AyARS: PUBLICATIONS AND PuBLic RELATIONS 207 respondence, for the preparation of pa- pers for the press, the correction of proofs, and other clerical service.” To the ‘‘effi- cient secretary’ was soon assigned the “labeling, determination, and arrange- ment of the insect collections’ of the State Laboratory (Forbes 1887:2). By 1896 he was listed as Systematic En- tomologist and Curator of Collections (Forbes 1896:2). Miss Snyder joined the staff of the State Laboratory of Natural History in 1883 and retired from the staff of the Natural History Survey in 1925. She died in 1938 at the age of 93 years. She was listed successively as amanuensis, stenographer, secretary, and editor and proofreader. Apparently, as Hart’s ento- mological activities increased, his editorial duties were taken over by Miss Snyder. A scientist who knew Miss Snyder well characterized her recently as “an excellent editor.” He added, “‘overcritical in a way.” Good editors, like good scientists, are apt to be “overcritical in a way.” Tradition reports that Forbes was not easily satisfied either with his own or his assistants’ papers, that he was meticulous about detail. H. H. Chapman, Yale University staff member who worked on forestry prob- lems for the Natural History Survey dur- ing the summers of 1922 and 1923, stated recently that Forbes was accustomed ‘“‘to revising the reports of his subordinates, cutting them down to about one-fourth of their original bulk” (letter of July 10, 1958, from H. H. Chapman to C. W. Walters). Successor to Miss Snyder in 1926 was H. Carl Oesterling, who for 2 years, be- fore he was appointed full-time Editor of the Natural History Survey, was em- ployed jointly by the Illinois Geological Survey, Illinois Water Survey, and Nat- ural History Survey. Oesterling had previ- ously taught at the University of Illinois. After Oéesterling went to the Univer- sity of Illinois Press in 1931, Carroll B. Chouinard was appointed to replace him. Following Chouinard’s appointment, the editorial office was called the Section of Publications. Chouinard resigned in 1937 to go to Pennsylvania State College, and James S. Ayars was appointed Editor. In 1947 the title of Editor was changed to 208 Technical Editor. In 1948 the Section of Publications was renamed the Section of Publications and Public Relations. Until Mrs. Blanche Penrod Young was appointed Assistant Technical Editor in September, 1948, the editorial staff had consisted of the Editor and temporary or part-time assistants. In 1958 Mrs. Diana Root Braverman was appointed as a sec- ond Assistant Technical Editor. For many years photographs for illus- trating publications have been taken by members of the technical staff. More than 60 years ago, Forbes (1894:36) mentioned in a biennial report “a dark room for photography” among the rooms available to the State Laboratory of Nat- ural History. Robert E. Hesselschwerdt was the first person on the staff whose title in- cluded the word photographer. He was appointed Assistant Technical Photogra- pher in 1946 and assigned to the Section of Publications. Upon his resignation in 1948, he was replaced by Charles L. Scott, who is now picture editor of the Milwaukee Journal. William E. Clark, the present staff photographer, was appointed in April, 1951. PUBLIC RELATIONS Long before public relations in name were added to Illinois Natural History Survey activities, public relations in fact were being practiced with consummate skill. Forbes had a natural flair for pub- lic speaking and for writing. He was popular as a speaker before scientific, ag- ricultural, and educational groups. His articles on insects and other subjects were welcomed by editors. In a biennial report Forbes (1888:8) mentioned “a considerable number of articles written for the agricultural papers in response to inquiries from their editors.” His well-organized, stimulating, even exciting reports of accomplishments by, or plans for, the agencies he represented were included as important parts of larger reports by university presidents or other administrators. In recent years public relations media have included principally news releases (to press, radio, and television), educa- ILtinois NaturAL History SurvEY BULLETIN Vol. 27, Art. 2 tional motion pictures, photographs, and magazine feature articles. Many public contacts have been made each year by the Chief and members of the staff in ad- dressing groups of persons interested in biological sciences and related subjects. EDITORIAL POLICY The scientific articles published by the founding fathers of the Illinois Natural History Survey and by Forbes and his contemporaries set standards of excel- lence that have served as a tradition and a challenge to subsequent members of the staff. Through the years, exactness of re- search and quality of the published re- ports based on research have been given precedence over quantity of research and speed of publication. Most of the organi- zation’s reports that stand as landmarks in biological literature were several years in the making. Extreme examples are some of the reports on the extensive bird studies made in 1905-1909; the last of the reports on these studies was not pub- lished until 1923 (Forbes 19075, 1908, 1913; Forbes & Gross 1921, 1922, 1923). Even 70 or more years ago, when print- ing and engraving processes were less ef- ficient than now, Forbes laid great stress on adequate illustrations. His policy with respect to adequate illustrations has been continued, and with improvement in printing and engraving processes have come changes in illustration practices that have added to the convenience of readers. Instead of grouping illustrations at the end of an article, as Forbes was sometimes forced to do, recent editors have been able to place each illustration close to its prin- cipal text reference. In the writing and editing of reports designed for publication is still felt the influence of the founding fathers, the classicists who sought to broaden the base of education. Respect for words is combined with respect for persons, the po- tential readers. Editorial problems have not been so simple in the past half century as when Wilber (1861d:3) wrote that “the sub- jects have generally been treated in a pop- ular rather than a technical style.” The wide range of subject matter and the di- versity of interests of the various reader December, 1958 groups served by the Natural History Survey have made necessary a diversity of style and even of format. Each report to be published is written and edited for a particular reader group in the hope that to this group the report will be “immedi- ately useful and interesting.” The joint aim of the writer, or writers, and the editorial staff is to make each published paper an orderly, logical presen- Ayars: PUBLICATIONS AND PuBLIC RELATIONS 209 tation of the results of a particular seg- ment of research; to include all pertinent data and to exclude all inconsequential or extraneous matter; to achieve accu- racy in original data and in quoted and paraphrased material; to state only such conclusions as can be justified by data presented; to make all statements so clear that they can be easily understood and cannot readily be misunderstood. Library HEN Cyrus Thomas proposed a Natural History Society of Illinois in 1857, his plan provided for the de- velopment of a library. In the letter out- lining his plan, we find this statement: “That such works as can be collected by gift, which will be useful in the investiga- tion of Natural History and relate there- to, be gathered by the members to form a library” (Bateman 1858a:12). While the Natural History Society was in the process of organization, Dr. E. R. Roe of Bloomington reported for the Committee on Library (Wilber 186ld: 12): “That it shall contain all available works on the Natural Sciences, Home and Foreign Surveys, Manuals, Works of Reference in the several departments, Miscellaneous Works, not strictly scien- tific, Maps and Charts, etc.” THE LIBRARY AT NORMAL When the Society received its charter from the state legislature in 1861, a li- brary was provided for in Section 3 (Wilber 1861d:15): Said natural history society shall also pro- vide for a library of scientific works, reports of home and foreign surveys, manuals, maps, charts, etc., etc., such as may be useful in determining the fauna and flora of Illinois, and said library shall be kept in the museum of said society at the State Normal University. This library, while it was still at I]li- nois State Normal University, Normal, was transferred to the Illinois State Lab- oratory of Natural History when the Laboratory was created in 1877. The library served not only the mem- bers of the Natural History Society and the State Laboratory; it was used by naturalists located in other parts of the state. In the report for 1879-1880 (Forbes 1880f : 9-20), a classified list of more than 300 titles of the principal works added during that period was included. This list was for the “benefit of the students of natural science throughout the State” and included works on mammals, birds, RUTH RR WARRIGw reptiles, fishes, insects, plants, and mis- cellaneous biological subjects. THE LIBRARY AT URBANA In 1885, when Forbes accepted the position of Professor of Zoology and En- tomology at Illinois Industrial Univer- sity (soon to become the University of Illinois), he made the request that the property of the State Laboratory of Nat- ural History be transferred to this Uni- versity (Burrill 1887a:10-1). “The es- sentials of my original work and of the State natural history survey can be trans- ferred from the Normal building to the basement of the University without detriment to any part of the work of the Normal School, . . .” The property transferred included the library (Burrill 1887a:101). A special project of the State Labora- tory of Natural History in 1893 was an exhibit of the zoology of Illinois at the Columbian Exposition, held in Chicago. This exhibit included a section of the library, ‘“‘the books selected being mainly entomological, and including serial publi- cations, periodicals, monographs, reference books, pamphlets, etc., to the number of about five hundred volumes” (Forbes 1894:7). When the biological station was estab- lished near Havana in 1894, the libraries of the University and of the Laboratory supplied a working library of about 120 volumes (Forbes 1894:3, 19). The floating laboratory, launched in April, 1896, had a cabin that at one end housed an office and library, 11 feet, 6 inches by 16 feet. A 24-page illustrated pamphlet describing the biological sta- tion contained the information that to summer students doing research ‘access will be given to the biological library of the Station. Books will also be loaned, as needed, from the library of the State Labo- ratory of Natural History and from that of the University of Illinois” (Forbes 1896:16, 26-7). [ 210 ] December, 1958 The library remained in the possession of the State Laboratory of Natural His- tory and its successor, the State Natural History Survey, until 1928, when it was turned over to the University of Illinois Library (Cunningham 1928:275-6). This transfer was made with the follow- ing stipulations: 1. That each article now belonging to the library of the Natural History Survey or added to it hereafter shall bear a distinctive mark; 2. That such additions shall be made to it, from time to time, as are necessary to the work of the Natural History Survey as certified by the Chief thereof and approved by the President of the University; and 3. That the scientific staff of the Natural History Survey shall have at all times a prior right to the use of books, pamphlets, and papers of the aforesaid library, their use by members of the faculty and by the students of the University being second to this claim. When the Natural History Building was completed, the library moved to the rooms assigned to it (Forbes 1894:35-6). Since my last report to you the State Labora- tory has removed to the rooms assigned to it in the new Natural History Hall of the University of Illinois, five on the first floor and two in the basement. These rooms are a Director’s office, 21 ft.x19 ft., a library room 7115 i Ra Provision was again made for a sepa- rate library when the Natural Resources Building was planned. Plans for trans- ferring the book collection from the Nat- ural History Building to the Natural Resources Building were being considered as early as July, 1939. A letter dated July 26, 1939, from Dr. P. L. Windsor, Director of University Libraries, to Dr. T. H. Frison, Chief of the Natural His- tory Survey, contained this statement: I am beginning to think of the preparations that will have to be made when the State Survey building is completed and you take over with you, such parts of the Natural His- tory Library as you think are necessary for your current work. After much planning and working out of policies, an agreement between the Nat- ural History Survey and the University was reached. This agreement was out- lined in a letter dated January 22, 1941, from Dr. Carl M. White, then Director of University Libraries, to Dr. Frison, as follows: WARRICK: LIBRARY 211 (1) The University is to catalog all books, journals, etc., including arrears and recata- loging. (2) The University is to provide in the regular library budget a fund for the pur- chase of books for the Natural History Sur- vey (at present $400). (3) The University is to manage the Nat- ural History Survey Library the same as other departmental libraries, including provi- sion of service to the Natural History Survey from other libraries on the campus. The pro- fessional staff of the Survey is to receive service from the various libraries on the campus on the same basis as the faculty of the University. (4) The University is to allow the Natural History Survey “preferred use” of the ma- terial in the Natural History Survey Library as “preferred use” is defined in your letter to me of December 16. (5) The University is to provide, besides general supervision, the sum of $700 in 1940- 41 for staff in the Natural History Survey Library. It is to provide $1500 for each year of the biennium 1941-43. (6) The Natural History Survey is to pro- vide housing for such books as need to be housed in the Natural Resources Building. (7) The Survey is to relieve the University September 1, 1943, of the responsibility for providing staff for library service. The Natural History Survey Library, opened as a separate unit in September, 1940 (Lill 1942:1), was located on the fourth floor of the Natural Resources Building, and remained in that location until the west wing of the Natural Re- sources Building was completed. In Feb- ruary, 1952 (Simmons 1952:1), the li- brary was moved to its permanent loca- tion on the first floor at the south end of the west wing. LIBRARY COLLECTIONS In a paper, “Natural History in Schools,” which was read before the IIli- nois State Teachers’ Association in 1860, A. M. Gow of Dixon gave a brief his- tory of the Illinois Natural History So- ciety and stated that its library at that time contained 300 volumes (Gow 1861: 96). Professor Forbes in his 1881-1882 re- port stated that additions to the library since his last report had been 360 vol- umes and 200 pamphlets, many of them “rare and costly works—the foundation stones of zoological and botanical litera- ture’ (Forbes 1882a:7). He wrote that 212 Ittinois NarurAL History Survey BULLETIN “particular attention has been paid to cataloguing, and this has been kept fully abreast of the additions. A card catalogue of authors is now absolutely complete to date, and a subject catalogue is well under way.” In 1885, when the State Laboratory of Natural History was transferred from Illinois State Normal University to the University of Illinois at Urbana, the li- brary had a collection of 1,207 bound volumes and 3,856 pamphlets and period- icals (Burrill 1887a:101). The library additions in 1899-1900 were 648 volumes and 764 pamphlets (Forbes 1901:11). Professor Forbes in 1909 stated that the library then had nearly 7,000 books and something over 17,000 pamphlets (Forbes 1909 :55-6). The library at present contains over 19,000 volumes and approximately 5,000 pamphlets, the greater part being period- icals and other serials. The field of en- tomology is represented most strongly in the collection, but other subjects, such as Vol. 27, Art. 2 zoology, botany, wildlife, and conserva- tion, are emphasized. For many years, the library has added to its collection by exchanging the publi- cations of the State Laboratory of Nat- ural History and the Natural History Survey with other institutions. The policy toward exchanges was expressed by Mr. Gow (1861:96) nearly 100 years ago: “The library of the Society will embrace everything that can be procured by gift, purchase or exchange, upon Natural His- tory in particular, and Science in general.” As the number of publications of the State Laboratory increased, the library was able to establish a larger number of exchanges, especially with European so- cieties and institutions (Forbes 1901:10). We are now receiving in exchange for our State Laboratory Bulletin one hundred and eighty-one periodical scientific publications, of which fifty-nine are American, twenty- eight are British or British-colonial, twenty- six are German, sixteen French, twelve Ital- ian, and the remaining forty are Russian, Swedish, Norwegian, Danish, Dutch, Hun- v Part of the Illinois Natural History Survey library in the Natural Resources Building. This library is noted especially for its large collection of bound volumes of periodicals in the bio- logical sciences. December, 1958 garian, Portugese, Egyptian, South American, and Japanese. At the present time the library has an exchange arrangement with approximately 500 scientific institutions and societies, a large number of which are foreign. LIBRARY PERSONNEL Provision for the care of the library has been made from the beginning of the Natural History Society to the present time. The person in charge of the library has always had the title /ibrarian and has been a member of the staff, first of the Natural History Society (Wilber 1861d:10) and later a member of the staff of each of the state agencies that fol- lowed, except for a period from 1928 (Cunningham 1928:275) to 1943 when the University of Illinois assumed full responsibility for the book collection. The first librarian was Ira Moore, instructor in mathematics at Illinois State Normal University (Wilber 1861d:10; Hovey 1859:401). His duties were def- initely stated in the Report of Committee on Library (Wilber 1861d:12): It shall be the duty of the Librarian to arrange the books of the Society, to make and keep a catalogue of the same, to keep a rec- ord of the books drawn from the library as directed by the Society, and report to the Society at its annual meeting. In a report to the Regent of the Uni- versity of Illinois in 1886, Professor Forbes mentioned a librarian among the personnel of the State Laboratory (Bur- rill 1887a:101). Henry Clinton Forbes served as Librarian and Business Agent of the Laboratory from 1892 to 1902 (Pillsbury 1892:284; 1894:135; 1896: [14]; 1898:[15]; 1901:xvir; 1902:xx). The policy of appointing professional librarians was started in 1906 with the appointment of Miss Edna Lucy Goss, B.L.S. (Pillsbury 1906:xxm) and has continued to the present. FINANCIAL SUPPORT Financial support for the library has always been considered of great import- ance. It was considered important even before the Illinois Natural History So- ciety became a chartered organization. In WARRICK: LIBRARY 213 the Report of Committee on Library, the following provision for a library was made (Wilber 1861d:12) : “That the So- ciety devote all moneys obtained by do- nations and memberships to this import- ant object [library], except so much as are necessary for expenses.”’ In an early report of the Director of the State Laboratory of Natural History, a plea was made for a public scientific library (Forbes 18785:5-6) : A most indispensable requisite for thorough work in any direction is an increase of the Library. Much of the time and money al- ready invested in the Laboratory collections and belongings must lie idle until this im- provement is made. There is not anywhere within reach of our naturalists a_ scientific library sufficient to assist them to reliable original work in any department of natural history. Nothing which the State could do for science would so stimulate a productive ac- tivity among them as a moderate appropria- tion for a public scientific library; and there is evidently no place where this library may be so properly built up as in connection with the State Laboratory of Natural His- tory. I have therefore included the sum of $2,000 for this purpose in my estimates, and the further sum of $200 for the services of a Librarian, to catalogue and thoroughly or- ganize the accessions on the plan already in use. This plan of organization place[s] the re- sources of the library at the ready command of the investigator, without requiring that com- plete previous acquaintance with the litera- ture of his subject which he can gain only by long use of a large library. It is proposed to use the money which may be voted for library purposes, first of all to procure those books now actually needed by our Illinois naturalists for the successful prosecution of the original investigations upon which they are at present engaged, and to provide for’ the future only when these present pressing needs have been supplied. The state legislature granted part of the appropriation requested by Professor Forbes. In a subsequent report he made a statement concerning the value of the library (Forbes 1880f:9) : No expenditure made by the Laboratory during the last two years has been so im- mediately profitable, both to the work of the establishment and to the studies of other naturalists, as that made for new _ books. While the additions are very few compared with the literature needed, they have cleared the field of difficulties which have blocked the progress of our work for years, and have first made possible to the students of our local natural history, original work of a satisfac- tory character, in a few departments of zoology and botany. 214 The library received its support from appropriations made by the state legisla- ture to the State Laboratory or Natural History Survey until the books were transferred to the University of Illinois, at which time the University assumed the responsibility for the book collection (Cunningham 1928 :275-6). After 100 years of library service to the staff and to the naturalists of the Ittinots NarurAL History Survey BULLETIN world .. Vol. 27, Art. 2— state, we hope that a statement made by | Professor Forbes a half century ago is — still true and that the library will always | maintain the high standard set for it by its founders. “Apart from its collections, . the most useful possession of the Paborsints is its library, which is the — product of many years of careful selection and purchase of the literature of the .” (Forbes 1909:55). Former Technical Employees Illinois Natural History Society, Illinois State Entomologist’s Office, Illinois State Museum of Natural History, Illinois State Laboratory of Natural History, Illinois Natural History Survey OLLOWING is a partial list of for- mer employees of the Illinois Natural History Society (1858-1871), Illinois State Entomologist’s Office (1867-1917), Illinois State Museum of Natural His- tory (1871-1877), Illinois State Labora- tory of Natural History (1877-1917), and Illinois Natural History Survey (since 1917). The list is not complete be- cause early records are fragmentary or do not exist, and because, for the sake of brev- ity, it seemed desirable to omit the names of many short-term or part-time em- ployees. A number of collaborators who worked closely with regular staff members are not listed, although they made contri- butions to the official publications. Because ADAMS, CHARLES CHRISTOPHER Entomologist, 1896-1898 ADAMS, LEVERETT ALLEN Zoologist, 1929 ALEXANDER, CHARLES PAUL Entomologist, 1919-1922 ALEXOPOULOS, CONSTANTINE J. Botanist, 1930-1931 Ames, RALPH WOLFLEY Plant Pathologist, 1951-1952 ANDERSON, HArry WARREN Botanist, 1922 ANDERSON, JOHN M. Biologist, 1939-1941 APPLE, JAMES WILBUR Entomologist, 1943-1949 AUDEN, KENNETH FRANCIS Entomologist, 1925-1927 BAKER, FRANK COLLINS Zoologist, 1931-1932 BALDUF, WALTER VALENTINE Entomologist, 1923 BARNICKOL, PAUL GEORGE Aquatic Biologist, 1945-1948 Barrett, E. G. Botanist, 1931-1932 Braco, ALICE MARIE Entomologist, 1899-1900 BESS LE: 8. Eb As T of their important contributions to the work of the Natural History Society and the maintenance of its collections, the names of two early curators, C. D. Wilber (1858-1864) and Joseph A. Sewall (1864-1867), and of the first librarian, Ira Moore (1858-1863), have been in- cluded; all three were members of the staff of Illinois State Normal University. The first official employee whose sal- ary was paid from funds appropriated by the state legislature for that purpose was John Wesley Powell, appointed Curator in 1867. From this beginning, the staff has increased to its present total of 101. No present employees are included in the following list. BERGER, BERNARD GEORGE Entomologist, 1941-1945 BETTEN, CORNELIUS Entomologist, 1931 Brown, FRANK ARTHUR Zoologist, 1935 Burks, BARNARD De Witt Entomologist, 1937-1949 BurriL__, THOMAS JONATHAN Botanist, 1885-1892 BuTLER, Cyrus W. Biologist, 1880-1882 CAMPANA, RICHARD JOHN Plant Pathologist, 1952-1958 CAMPBELL, LEO Botanist, 1930-1931 CHANDLER, STEWART CURTIS Entomologist, 1917-1957 CHAPMAN, HERMAN HAuvupT Forester, 1922-1923 CHASE, ELIZABETH BROWN Biologist, 1945-1948 CHOUINARD, CARROLL BENEDICT Editor, 1931-1937 CoMPTON, CHARLES CHALMER Entomologist, 1921-1944 CoQuUILLETT, DANIEL WILLIAM Entomologist, 1881 [ 215] 216 Cralc, WALLACE Aquatic Biologist, 1898-1899 CRAWLEY, HENRI DouGLAs Forester, 1950-1951 CREAGER, Don BAXTER Plant Pathologist, 1939-1943 CuLVER, LAwson BLAINE Forester, 1947-1954 DANIELS, Eve Botanist, 1924-1926 Davis, JAMES ELwoop Forester, 1935-1947 Davis, JOHN JUNE Entomologist, 1907-1911 DeCourseEy, JOHN D. Entomologist, 1929-1932 DeELonc, Dwicut Moore Entomologist, 1934-1936, 1938, 1941, 1945 Dozier, HERBERT LAWRENCE Entomologist, 1932 Driver, ERNEST CHARLES Zoologist, 1930 Duccar, BENJAMIN MINGE Botanist, 1895-1896 DuRHAM, LEONARD Aquatic Biologist, 1947-1950 EARLE, FRANKLIN SUMNER Mycologist, 1886 Eppy, SAMUEL Botanist, 1925-1929 ELDER, WILLIAM HANNA Game Specialist, 1941-1943 ENGELHARD, ARTHUR WILLIAM Plant Pathologist, 1955-1956 FarrArR, MILTon Dyer Entomologist, 1931-1946 FELL, RACHEL M. Botanist, 1881-1882 Ferris, JOHN MAson Plant Pathologist, 1957-1958 Fisk, VERNON C., Forester, 1921-1923 FLINT, WESLEY PILLSBURY Entomologist, 1907-1943 ForsBeEs, ErNEST BROWNING Zoologist, 1894-1896, 1899-1901 Forspes, HENry CLINTON Librarian, 1894-1902 ForsBes, STEPHEN ALFRED Curator, State Museum of Natural History, 1872-1877 ; Director, State Laboratory of Natural History, 1877-1917; State Entomologist, 1882-1917; Chief, Natural History Survey, 1917-1930 Ittrnois NarurAL Hisrory Survey BULLETIN Vol. 27, Arte 2 Foster, T. DALE Zoologist, 1931-1932 FRENCH, GEORGE HAZEN Entomologist, 1877-1878 Frison, (THEODORE HENRY Entomologist, 1923-1930; Chief, Natural History Survey, 1930-1945 GARMAN, PHILIP Entomologist, 1914 GarRMAN, W. Harrison Zoologist, 1877-1889 GIRAULT, ALECANDRE ARSENE Entomologist, 1908-1911 GLascow, Ropert DouGLAss Entomologist, 1905-1909, 1912-1915, 1927 GLENN, PressLEY ADAMS Entomologist, 1911-1917 GopING, FREDERICK WEBSTER Entomologist, 1885 GorF, CarLos CLYDE Entomologist, 1927-1930 Goss, Epna Lucy Librarian, 1906-1908 Gross, ALFRED OTTo Ornithologist, 1906-1907, 1909, 1912 HANKINSON, THOMAS LEROY Zoologist, 1911 Harris, HUBERT ANDREW Botanist, 1930-1933 Hart, CHARLES ARTHUR Entomologist, 1880-1918 Hart, Lypta Moore Artist, 1891-1898 HaAwkKINsS, ARTHUR STUART Game Specialist, 1938-1945 Hayes, WILLIAM PaTRICK Entomologist, 1926, 1928-1934 HeEMPEL, ADOLPH Zoologist, 1894-1896 HESSELSCHWERDT, ROBERT EDWARD Zoologist, 1936-1942; Photographer, 1946-1948 HoFFMAN, PAUL FREDRICK, JR. Plant Pathologist, 1951-1954 Hoop, JosEpH DouGLaAs Entomologist, 1910-1912 Hortres, FREDERICK CHARLES Entomologist, 1928-1930 Hunt, Francis D. Aquatic Assistant, 1925-1937 Hunt, THOMAS ForsyTH Entomologist, 1885-1886 HutTcHENS, LYNN HENRY Aquatic Biologist, 1936-1938, 1946-1947 December, 1958 JANVRIN, CHARLES EDWIN Librarian, 1912-1929 JoHNSON, WILLIS GRANT Entomologist, 1894-1896 JORDAN, JAMES SCHUYLER Game Specialist, 1948-1955 KAHL, Huco Entomologist, 1892-1894, 1901-1902 KELLEY, GRACE Oscoop Librarian, 1908-1912 KNAB, FREDERICK Artist, 1903-1905 KNIGHT, HARryY HAZELTON Entomologist, 1930, 1932-1933, 1937 KNIGHT, KENNETH LEE Entomologist, 1938-1939 Korom, CHARLES ATWOOD Aquatic Biologist, 1895-1900 KRUMHOLZ, Louis A. Zoologist, 1938-1941 Kupo, RicHarp R. Zoologist, 1930 LarGcE, ‘THOMAS Aquatic Biologist, 1899-1902 Le Baron, WILLIAM Entomologist, 1870-1875 LEIGH, WALTER HENRY Game Specialist, 1935-1938 Low, Jessop BUDGE Game Specialist, 1941-1943 Luce, WILBUR MARSHALL Zoologist, 1929-1930, 1932 LuUETH, FRANCIS X. Zoologist, 1939-1940 McCauL.ey, WILLIAM EpWARD Entomologist, 1934-1941 McCiure, Howe EL tiorr Entomologist, 1930-1933 McCormick, A. K. Aquatic Biologist, 1881-1882 McDouGaL_, WALTER BYRON Botanist, 1928 MAaLiocH, JOHN RUSSELL Entomologist, 1913-1921 Matty, FREDERICK WILLIAM Entomologist, 1889-1890 Matrsy, Cora M. Librarian, 1885—1886 MarTEN, JOHN Entomologist, 1888—1894 Mippteton, Netrie Entomologist, 1878—1880 MiLier, AuGust Epwarp Entomologist, 1926-1928 Mier, Ross JEWELL Forester, 1947-1956 East: ForMER TECHNICAL EMPLOYEES MILNER, ANGE V. Librarian, 1880-1882 Moore, [RA Librarian, 1858-1863 Moore, THomAs EpwINn Entomologist, 1948-1956 NYBERG, FLORENCE ANNA Assistant to the Chief, 1922—1945 O’DonNELL, DoNALD JOHN Zoologist, 1931-1937 OkrSTERLING, H. Cari Editor, 1926-1931 PEAKE, CHARLEs O. Botanist, 1921-1923 Peirce, ALAN STANLEY Botanist, 1933-1934 PrEPOON, HERMAN S. Botanist, 1931-1933 PLUNKETT, Orpa ALLEN Botanist, 1922 Porter, CHARLES LYMAN Botanist, 1921-1922 PowWELL, JOHN WESLEY Curator, 1867-1872 Powers, Epwin Booty Entomologist, 1917 RASMUSSEN, DANIEL IRVIN Biologist, 1931-1932 RICHARDS, WILLIAM RoBIN Entomologist, 1950-1953 RICHARDSON, RoBert Ear Aquatic Biologist, 1903-1904, 1909-1933 RIEGEL, GARLAND TAVNER Entomologist, 1938-1942 Rres, DONALD TIMMERMAN Naturalist, 1938 ROBERTSON, WILLIAM BECKWITH, JR. Game Specialist, 1952-1956 SAWYER, LeEsLig EDWIN Forester, 1929-1935 SCHNEIDER, IRVING ROBERT Plant Pathologist, 1954-1956 SCHOPF, JAMES Botanist, 1931 SCHREEDER, W. F. Forester, 1921-1925 ScoTT, CHARLES L. Photographer, 1948-1951 SELANDER, RICHARD B. Entomologist, 1955—1958 SEWALL, JOSEPH A. Curator, 1864-1867 SEYMOUR, ARTHUR BLIss Botanist, 1881-1883, 1884, 1886 217 218 Ittinois NaruraAL History SurvEY BULLETIN SHELFORD, Victor ERNEST Ecologist, 1914-1927 SHOEMAKER, Hurst Zoologist, 1942, 1944 SHROPSHIRE, LESLIE HAROLD Entomologist, 1931-1942 Srmmons, LILLIAN MARGUERITE Librarian, 1943-1952 SMITH, Dora Biologist, 1894 SMITH, EMMaA A. Entomologist, 1877 SMITH, FRANK Zoologist, 1894-1897, 1907-1910 SmitH, LINDLEY MALCOLM Entomologist, 1907-1917 Snow, Francis HUNTINGTON Entomologist, 1892 SNYDER, Mary JANE Amanuensis and Editor, 1883-1925 SOMMERMAN, KATHRYN MARTHA Entomologist, 1939-1946 Sowts, Lyte K. Game Specialist, 1940-1941 SPOONER, CHARLES 5S. Entomologist, 1917-1920 SPOONER, CHARLES 5., JR. Biologist, 1939-1942 STANLEY, WILLARD FRANCIS Zoologist, 1935 Stout, GILBERT LEONIDAS Botanist, 1926-1930 SUMMERS, HENRY ELIJA Entomologist, 1892-1893 SURANY, PAUL Entomologist, 1950-1955 SuRFACE, HArvey ADAM Zoologist, 1899 ‘TANQUARY, Maurice COLE Entomologist, 1910-1912 ‘Taytor, Estes PARK Entomologist, 1903-1905 TEHON, Leo Roy Botanist, 1921-1954; Acting Chief, Natural History Survey, 1945-1946 LT EErorD; C.J. Forester, 1921-1929 ‘THOMAs, Cyrus Entomologist, 1875-1882 THompson, Davin Hiram Zoologist, 1923-1944 Tirus, EpwArp SHARP GAIGE Entomologist, 1902-1903 ‘TOWNSEND, LEE HILL Entomologist, 1932-1936 ‘TRUMBOWER, JOHN ABBOTT Botanist, 1932-1933 VAN CLEAVE, HARLEY JONES Parasitologist, 1911-1912 . Vasey, GEORGE W. Acting Curator, 1871-1872 VestTaAL, ARTHUR GIBSON Botanist, 1909 Von LIMBACH, BRUNO Zoologist, 1940-1945 Wap Ley, FrANcis MARION Entomologist, 1920 WALSH, BENJAMIN D. Entomologist, 1867-1869 WANDELL, WILLET NORBERT Forester, 1945-1954 WEBSTER, FRANCIS MARION Entomologist, 1881-1884, 1902-1904 WeEeEbD, CLARENCE Moores Entomologist, 1885-1888 WEINMAN, CarRL JOHN Entomologist, 1937-1952 West, JAMES ALEXANDER Entomologist, 1905-1908 Wiper, C. D. Curator, 1858-1864 Wo Lr, JOHN Botanist, 1880 Woop, FRANK ELMER Aquatic Biologist, 1905-1909 WoopwortH, C. W. Entomologist, 1884-1886 WriGcHt, JOHN McMaster Entomologist, 1943-1957 YEAGER, LEE EMMETT Forester, 1938-1945 YouNG, PAUL ALLEN Botanist, 1922-1925 Yuasa, HACHIRO Entomologist, 1921-1922 ZETEK, JAMES Entomologist, 1909-1911 ZUCKERMAN, Bert MERTON Plant Pathologist, 1951-1954 Vol. 27, Art. 2 PLEA TORE. Cit BD Agassiz, Louis 1863. Methods of study in natural history. Ticknor & Fields, Boston. viiit319 pp- Alexander, Charles P. 1925. An entomological survey of the Salt Fork of the Vermilion River in 1921, with a bibliography of aquatic in- sects. Ill. Nat. Hist. Surv. Bul. 15(8) :439-535. Anonymous 1860. The anniversary week at Blooming- ton. The agricultural convention; annual meeting of the Illinois Nat- ural History Society, and commence- ment exercises of the State Normal University. Chiefly compiled from the reports of the Chicago Press and Tribune and Chicago Times, Chi- cago. 67 pp. Professor S. A. Forbes, dies after more than 60 years of service to the University and State. Ill. Alumni News 8(7) :278-82. Fieldbook of Illinois wild flowers. Ill. Nat. Hist. Surv. Man. 1. x+406 pp. Ayars, James S. 1956. Leo Roy Tehon, 1895-1954. Ill. Acad. Sci. Trans. for 1955, 48:224—5. Babcock, H. H. 1930. 1936. 1872. The flora of Chicago and vicinity. The Lens 1(1):20-6; 1(2):65-71; 1(3) 144-50; 1(4) :218-22. Baker, Frank Collins 1906. A catalogue of the Mollusca of Illi- nois. Ill. Lab. Nat. Hist. Bul. 7(6): 53-136. Fieldbook of Illinois land snails. III. Nat. Hist. Surv. Man. 2. 166 pp. Balham, Ronald W., and Wm. H. Elder 1953. Colored leg bands for waterfowl. Jour. Wildlife Mgt. 17(4) :446-9. Bannister, Henry M. 1868. Geology of Cook County. Pp. 239-56 in Vol. III, Geological Survey of Illinois, A. H. Worthen, Director. Springfield, Illinois. Barnard, W. S. 1880. Notes on the development of a black- fly (Simulium) common in the rapids around Ithaca, N. Y. Am. Ent., n.s., 1(8) :191-3. Barney, R. L. 1924. A confirmation of Borodin’s scale method of age determination of Con- necticut River shad. Am. Fish. Soc. Trans. for 1924, 54:168-77. Barnickol, Paul G., and William C. Starrett 1951. Commercial and sport fishes of the Mississippi River between Caruth- ersville, Missouri, and Dubuque, Iowa. Ill. Nat. Hist. Surv. Bul. 25 (5) :267-350. 1939. Bartlett, S. P., Secretary 1893. Report of the Commissioners. III. Fish Commrs. Rep. 1890-1892. 52 pp. Bateman, Newton, Editor 1858a. The meeting at Decatur. Il]. Teacher 4(1) :1-25. 1858. Natural History Society. Ill. Teacher 4(8) :258-9. Bateman, Newton, Secretary 1867. Proceedings of the Board of Educa- tion of the State of Illinois (Decem- ber 19, 1866; March 26, 1867). Pe- oria. 12 pp. Proceedings of the Board of Educa- tion of the State of Illinois (June 28, 29, 1871). Peoria. 20 pp. Proceedings of the Board of Educa- tion of the State of Illinois (June 26, 1872). Peoria. 12 pp. Bayless, Mrs. Anne Douglas 1871. 1872. 1957. The annual meeting—1957. Ill. Au- dubon Soc. Bul. 1957(102) :1-4. Bebb, M. S. 1859. List of plants occurring in the north- ern counties of the state of Illinois, in addition to the catalogue given by Dr. J. [sic] A. Lapham. Ill. Ag. Soc. Trans. for 1857-1858, 3:586-7. Beck, Lewis C. 1826a. Contributions towards the botany of the states of Illinois and Missouri. Am. Jour. Sci. and Arts 10(2) :257- 64. 1826. Contributions towards the botany of the states of Illinois and Missouri. Am. Jour. Sci. and Arts 11(1) :167- 82. Contributions towards the botany of the states of Illinois and Missouri. Am. Jour. Sci. and Arts 14(1) :112- 21. Bellrose, Frank C. 1940. Quail and pheasant studies in an orchard county. Ill. Nat. Hist. Surv. Biol. Notes 13. 11 pp. Duck food plants of the River valley. Ill. Nat. Hist. Bul. 21(8) :237-80. Duck populations and kill: an evalu- ation of some waterfowl regulations in Illinois. Ill. Nat. Hist. Surv. Bul. 23\(2)) 2327-72. Relative values of drained and un- drained bottomland in Illinois. Jour. Wildlife Mgt. 9(3) :161-82. The relationship of muskrat popula- tions to various marsh and aquatic plants. Jour. Wildlife Mgt. 14(3): 299-315. 1953a. Housing for wood ducks. IIl. Hist. Surv. Circ. 45. 47 pp. 1953b. A preliminary evaluation of cripple losses in waterfowl. N. Am. Wild- life Conf. Trans. 18:337-60. 1828. Illinois Surv. 1941. 1944. 1945. 1950. Nat. [219] 220 I-tinors NaturAt History SurvEY BULLETIN 1954. The value of waterfowl refuges in Illinois. Jour. Wildlife Mgt. 18(2): 160-9. A spectacular waterfowl migration through central North America. Ill, Nat. Hist. Surv. Biol. Notes 36. 24 1957. Pp. 1958a. The orientation of displaced water- fowl in migration. Wilson Bul. 70(1) :20-40. 1958b. Celestial orientation by wild mal- lards. Bird-Banding 29(2) :75-90. Lead poisoning as a mortality factor in waterfowl populations. Ill. Nat. Hist. Surv. Bul. 27(3). In press. Bellrose, Frank C., and Harry G. Anderson 1943. Preferential rating of duck food plants. Ill. Nat. Hist. Surv. Bul. 22(5) :417-33. Bellrose, Frank C., and Louis G. Brown 1941. The effect of fluctuating water levels on the muskrat population of the Illinois River valley. Jour. Wildlife Mgt. 5(2) :206-12. Bellrose, Frank C., and Elizabeth Brown Chase 1950. 1959. Population losses in the mallard, black duck, and blue-winged teal. Ill. Nat. Hist. Surv. Biol. Notes 22. 27 pp. Bellrose, Frank C., and Jessop B. Low 1943. The influence of flood and low water levels on the survival of muskrats. Jour. Mammal. 24(2) :173-88. Bellrose, Frank C., and Clair T. Rollings 1949. Wildlife and fishery values of bot- tomland lakes in Illinois. Ill. Nat. Hist. Surv. Biol. Notes 21. 24 pp. Bennett, George W. 1943. Management of small artificial lakes: a summary of fisheries investiga- tions, 1938-1942. Ill. Nat. Hist. Surv. Bul. 22(3) :357-76. 1947. Fish management—a substitute for natural predation. N. Am. Wildlife Conf. Trans. 12:276-84. 1948. The bass-bluegi!l combination in a small artificial lake. Ill. Nat. Hist. Surv. Bul. 24(3) :377-412. 1952. Pond management in Illinois. Jour. Wildlife Mgt. 16(3) :249-53. 1954a. Largemouth bass in Ridge Lake, Coles County, Illinois. Ill. Nat. Hist. Surv. Bul. 26(2) :217-76. 1954b. The effects of a late-summer draw- down on the fish pcpulation of Ridge Lake, Coles County, Illinois. N. Am. Wildlife Conf. Trans. 19:259-70. Bennett, George W., David H. Thompson, and Sam A. Parr 1940. Lake management reports. 4. A sec- ond year of fisheries investigations at Fork Lake, 1939. Ill. Nat. Hist. Surv. Biol. Notes 14. 24 pp. Birge, E. A. 1929. Fish and their food. Am. Fish. Soc. Trans. for 1929, 59:188—-94. Vol. 27, Art. 2 Boewe, G. H. 1939. Diseases of small grain crops in Illi- — nois. Ill. Nat. Hist. Surv. Cire. 35. 130 pp. Borodin, N. 1924. Age of shad (Alosa sapidissima Wil- son) as determined by the scales. Am. Fish. Soc. Trans. for 54:178-84. Brendel, Frederick 1857. Historical researches upon the culti- vated grain fruits in the state of IIli- nois. Ill. Ag. Soc. Trans. for 1856- — 1857, 2:471-83. 1859a. Additions and annotations to Mr. Lapham’s catalogue of Illinois plants. Ill. Ag. Soc. Trans. for 1857-1858, 3:583-5. 1859b. The trees and shrubs in Illinois. Ill. Ag. Soc. Trans. for 1857-1858, 3:588- 604. 1859c. The oaks of Illinois. Ill. Ag. Soc. Trans. for 1857-1858, 3:605-31. 1859d. Forests and forest trees. Ill. Ag. Soc. Trans. for 1857-1858, 3:651-61. Botanical notes. Notices and addi- tions to Illinois flora. Prairie Farmer, n.s., 6(19):294-5. [Author’s name given as Fred. Brendell.] The water lily. On the peculiar growth of the water lily (Nelumbium luteum Willd.). Ml. Nat. Hist. Soc. Trans. 2nd ed. Ser. 1, 1:65-7. Occurrence of rare plants in Illinois. Am. Nat. 4(6) :374. [Brendel, Frederick] 1876. The tree in winter. IIl. Hist. Bul. 1(1) :26-32. Brendel, Frederick 1887. Flora Peoriana. The vegetation in the climate of middle Illinois. J. W. Franks and Sons, Peoria. 89 pp. Brown, Louis G., and Lee E. Yeager 1860. 1861. Mus. Nat. 1943. Survey of the Illinois fur resource. Ill. Nat. Hist. Surv. Bul. 22(6) :435- 504. 1945. Fox squirrels and gray squirrels in Illinois. Ill. Nat. Hist. Surv. Bul. 23(5) :449-536. Bruce, Willis N. 1952. Automatic sprayer for control of bit- ing flies on cattle. Ill. Nat. Hist. Surv. Biol. Notes 27. 11 pp. 1953. A new technique in control of the house fly. Ill. Nat. Hist. Surv. Biol. Notes 33. 8 pp. Bruce, W. N., and George C. Decker 1951. Tabanid control on dairy and beef cattle with synergized pyrethrins. Jour. Econ. Ent. 44(2) :154-9. Experiments with several repellent formulations applied to cattle for control of stable flies. Jour. Econ. Ent. 50(6) :709-13. The relationship of stable fly abun- dance to milk production in dairy cattle. Jour. Econ. Ent. 51(3) :269-74. OST. 1958. 1924, | | : December, 1958 Brush, H. L. 1857. On the culture of the vine in IIli- nois. Ill. Ag. Soc. Trans. for 1856— 1857, 2:407-12. Burks, B. D. 1953. The mayflies, or Ephemeroptera, of Illinois. Ill. Nat. Hist. Surv. Bul. 26(1) :1-216. Burr, J. G. 1931. Electricity as a means of garfish and carp control. Am. Fish. Soc. Trans. for 1931, 61:174-81. Burrill, Thomas J. 1874. Aggressive parasitism of fungi. III. Hort. Soc. Trans. for 1873, ms., 7:217-21. 1876. Lettuce mould and leaf blights. III. Hort. Soc. Trans. for 1875, ms., 9:139-44. 1877. Injurious fungi. Ill. Hort. Soc. Trans. for 1876, n.s., 10:213-20. 1881. Blight, or bacteria-ferments, in fruit trees. Ind. Hort. Soc. Trans. for 1880, 20:84-91. 1885. Parasitic fungi of Illinois—Part I. Ill. Lab. Nat. Hist. Bul. 2(3) :141- 255. 1886. Annual address of the president: Bacteria and disease. Am. Soc. Mi- croscopists Proc. for 1886, 8:5-29. Burrill, Thomas J., Corresponding Secretary 1887a. Thirteenth report . . . of the Board of Trustees of the University of Illinois (Illinois Industrial Univer- sity) ... for the two years ending September 30, 1886. 305 pp. Burrill, Thomas J. 1887b. The forest-tree plantation. II]. Univ. Rep. 13:255-82. 1887c. A disease of broom-corn and _ sor- ghum. Soc. Prom. Ag. Sci. Proc. 8:30-6. 1888. Drouth and trees. Ill. Hort. Soc. Trans. for 1887, n.s., 21:110-7. 1889a. Road and _ street horticulture. III. Hort. Soc. Trans. for 1888, ns., 22:153-9. 1889). The biology of ensilage. Ill. Ag. Exp. Sta. Bul. 7:177-94. 1890. Canada thistles, their extermination. Ill. Ag. Exp. Sta. Bul. 12:379-87. 1903. Experiments in spraying for bitter rot. Ill. Hort. Soc. Trans. for 1902, n.s., 36:54-66. Campbell, F. L. 1946. Valediction: Theodore Henry Frison. Sci. Monthly 62:91-3. Carbine, W. F. 1939. Observations on the spawning habits of centrarchid fishes in Deep Lake, Oakland County, Michigan. N. Am. Wildlife Conf. Trans. 4:275-87. Carriel, Mary Turner 1911. The life of Jonathan Baldwin Tur- ner. [Published by the author, Jack- sonville, Illinois.] 298 pp. LITERATURE CITED 221 Carter, J. Cedric 1939. Progress in the control of elm dis- eases in nurseries. Ill. Nat. Hist. Surv. Biol. Notes 10. 19 pp. 1941. Preliminary investigation of oak dis- eases in Illinois. Ill. Nat. Hist. Sury. Bul. 21(6) :195-230 1945. Wetwood of elms. III. Nat. Hist. Surv. Bul. 23(4) :407-48. 1952. Distribution and spread of oak wilt in Illinois. U. S. Dept. Ag. Plant Dis. Reptr. 36(1) :26-7. 1955. Leo Roy Tehon, 1895-1954. Phyto- pathology 45(3) :115. Carter, J. C., and Noel B. Wysong 1951. Isolation of the oak wilt fungus from swamp white oak. U. S. Dept. Ag. Plant Dis. Reptr. 35(3) :173-4. Carver, Jonathan 1778. Travels through the interior parts of North-America, in the years 1766, 1767, and 1768. Printed for the au- thor, London. 543 pp. Chapman, Herman H., and Robert B. Miller 1924. Second report on a forest survey of Illinois. The economics of forestry in the state. Ill. Nat. Hist. Surv. Bul. 15(3) :46-172. Coquillett, D. W. 1881. Larvae of Lepidoptera. Ill. Ent. Rep. 10:142-86. [Coues, Elliott] 1 83. Birds and insects. Nuttall Ornith. Club Bul. 8(2) :105-7. Creager, Donald B. 194+1a. Ring spot of popular peperomias caused by virus. Florists’ Rev. 87 (2256) :15-6. 1941. Control black mold of rose grafts by chemical treatments. Florists’ Rev. 89 (2290) :21-2. 1941c. Control program for peony measles. Florists’ Rev. 89(2296) :22-3. 1942. Thielavia root rot of sweet peas and its control. II]. Florists’ Assn. Bul. 62 :284—5. 1943a. Spraying ground with Elgetol con- trols peony disease. III. Florists’ Assn. Bul. 68:311-3. 1943b. Prevention of disease losses in callas. Ill. Florists’ Assn. Bul. 73:340-3. 1943¢. Carnation mosaic. Phytopathology 33 (9) :823-7. 1944. How to recognize and control mosaic on carnation plants. Florists’ Rev. 93 (2409) :27-9. 1945. Mosaic of the common coleus. Phyto- pathology 35(4) :223-9. Cresson, E. T., Aus. R. Grote, J. W. McAllister, Benj. D. Walsh, Editors 1865. Answers to correspondents. Pract. Ent. 1(3) :18-9. Cunningham, Harrison E., Secretary 1928. Thirty-fourth report of the Board of Trustees of the University 222 of Illinois for the two years ending June 30, 1928. Ixi+840 pp. Curl, E. A. 1953. Studies on the availability of oak wilt inoculum in Illinois. Phytopa- thology 43(9) : 469. 1955a. Natural availability of oak wilt in- ocula. Ill. Nat. Hist. Surv. Bul. 26(3) :277-323. 1955b. Removal of spores from mycelial mats and transmission of Endoconidi- ophora fagacearum by air currents. U. S. Dept. Ag. Plant Dis. Reptr. 39 (12) : 977-82. Curl, E. A., G. J. Stessel, and Bert M. Zuckerman 1952. Macroscopic growth of the oak wilt fungus in nature. Phytopathology 42(1):6. Subcortical mycelial mats and peri- thecia of the oak wilt fungus in na- ture. Phytopathology 43(2) :61-4. Davis, John J. 1913. The Cyrus Thomas collection of Aphididae, and a tabulation of spe- cies mentioned and described in his publications. Ill. Lab. Nat. Hist. Bul. 10(2) :97-121+2 pls. Contributions to a knowledge of the natural enemies of Phyllophaga. Ill. Nat. Hist. Surv. Bul. 13(5) :53-138 +13 pls. New species and varieties of Phyl- lophaga. Ill. Nat. Hist. Surv. Bul. 13 (12) :329-38+6 pls. Davis, N. S., Jr.. and Frank L. Rice 1883. Descriptive catalogue of North Amer- ican Batrachia and Reptilia, found east of Mississippi River. II]. Lab. Nat. Hist. Bul. 1(5) :3-64. DeLong, D. M. 1948. The leafhoppers, or Cicadellidae, of Illinois (Eurymelinae-Balcluthinae). Ill. Nat. Hist. Surv. Bul. 24(2) :97- 376. Deyo, V. K., Chairman of Committee 1867. Report on president’s address. Ill. Hort. Soc. Trans. for 1866, 11:57-8. Durham, Leonard 1955. Effects of predation by cormorants and gars on fish populations of ponds in Illinois. Thesis submitted as par- 1953. 1919. 1920. tial fulfillment for Ph.D. degree. University of Illinois, Urbana. iv+ 113 pp. Eames, J. P. 1857. Evergreen trees on the prairie. III. Ag. Soc. Trans. for 1856-1857, 2: 416-7. Earle, Parker 1868. President Earle’s address. II]. Hort. Soc. Trans. for 1867, n.s., 1:136-8. Ecke, Dean H. 1955. The reproductive cycle of the Mearns cottontail in Illinois. Am. Midland Nat. 53(2) :294-311. ILtinois NATURAL History SurRvEY BULLETIN Vol. 27, Art. 2 Ecke, Dean H., and Ralph E. Yeatter 1956. rabbits in Illinois. III. Trans. for 1955, 48:208-14. Eddy, Samuel 1927. The plankton of Lake Michigan. Ill. — Nat. Hist. Surv. Bul. 17(4) : 203-32. © 1931. The plankton of some sink hole ponds in southern Illinois. Ill. Nat. Hist. — Surv. Bul. 19(4) :449-67. 1932. The plankton of the Sangamon River in the summer of 1929. Ill. Nat. Hist. Surv. Bul. 19(5) :469-86. Edwards, Samuel 1857. Cultivation of evergreens. Soc. Trans. for 1856-1857, 2:413-5. 1868. Planting and cultivation of forest — trees. Ill. Ag. Soc. Trans. for 1865— ; 1866, 6:283-6. Elder, William H. 1946. Age and sex criteria and weights of Canada geese. 10(2) :93-111. Elder, William H., and Nina L. Elder 1949. of goose flocks. Wilson Bul. 61(3): 133-40. Engelmann, George [1843.] Catalogue of a collection of plants — made in Illinois and Missouri, by Charles A. Geyer; with critical re- marks, &c. 46(1) : 94-104. English, L. L. 1958. Illinois trees and shrubs: their insect — enemies. II], Nat. Hist. Surv. Cire. 47. 92 pp. Eschmeyer, R. W. 1938. The significance of fish population studies in lake management. N. Am. Wildlife Conf. Trans. 3:458-68. [Etter, S. M., Secretary] 1876. ber 15, 1875). Springfield. 20 pp. Etter, S. M., Secretary 1877. tion of the State of Illinois (June 21, 22, 1877). Springfield. 27 pp. Evers, Robert A. 1949. Setaria faberii in Illinois. 51 (612) :391-2. 1950. Andropogon elliottii Chapm. in Illi- — nois. Rhodora 52(614) :45-6. 5 1951. Four plants new to the Illinois flora. Rhodora 53(628) :111-3. 1955. Hill prairies of Illinois. Ill. Nat. Hist. Surv. Bul. 26(5) :367—446. 1956. Two plants new to the Illinois flora. Rhodora 58(686) :49-50. Evers, Robert A., and John W. Thieret 1957. New plant records: Illinois and Indi- ana. Rhodora 59(703) :181. Ewing, Henry E. 1909. The Oribatoidea of Illinois. Ill. Lab. Nat. Hist. Bul. 7(10) :337-89+3 pls. Notes on the parasites of cottontail — Acad. Sci. © Ill. Ag. | Jour. Wildlife Mgt. — Role of the family in the formation © Am. Jour. Sci. and Arts © Proceedings of, the Board of Educa- i tion of the State of Illinois (Decem- — Proceedings of the Board of Educa- j Rhodora p> eee aS SS we Se he er December, 1958 Fawks, Elton 1957. Our new hawk and owl law. III. Audubon Soc. Bul. 1957(103) :1-2. Finger, G. C., Frank H. Reed, and Leo R. Tehon 1955. Aromatic fluorine compounds as fun- gicides. Ill]. Geol. Surv. Circ. 199. 15 Pp. Flint, Wesley P., and John R. Malloch 1920. The European corn-borer and some similar native insects. II]. Nat. Hist. Surv. Bul. 13(10) :287-305. Forbes, Ernest Browning 1897. 1930. A contribution to a knowledge of North American fresh-water Cyclo- pidae. Ill. Lab. Nat. Hist. Bul. 5 (2) :27-96. Stephen Alfred Forbes: his ancestry, education and character. Pp. 5-15 in Memorial of the funeral services for Stephen Alfred Forbes, Ph.D., LL.D. University of Illinois Press, [Ur- bana]. 40 pp. Forbes, Stephen Alfred 1876. 1877. [1878 ]a. 1878). 1880a. 1880. 1880c. 1880d. 1880¢. [1880]f. 1881la. 1881. 1881c. [1882]a. List of Illinois Crustacea, with de- scriptions of new species. Ill. Mus. Nat. Hist. Bul. 1(1) :3-25. Report on the Museum of Natural History, at Normal. Ill. Supt. Pub. Instr. Bien. Rep. for 1874-1876, 11: 324-31. The food of Illinois fishes. Nat. Hist. Bul. 1(2) :71-89. Semi-annual report of the Director of the State Laboratory of Natural History, at Normal, Illinois. Filed December 16, 1878. Springfield. 6 pp. On some interactions of organisms. Ill. Lab. Nat. Hist. Bul. 1(3) :3-17. The food of fishes. Ill. Lab. Nat. Hist. Bul. 1(3) :18-65. On the food of young fishes. Lab. Nat. Hist. Bul. 1(3) :66-79. Il]. Lab. Hl. The food of birds. Ill. Lab. Nat. Hist. Bul. 1(3) :80-148. The food of birds. Ill. Hort. Soc. Trans. for 1879, n.s., 13:120-72. Report of the Director of the State Laboratory of Natural History. 24 pp. [Also in Ill. Supt. Pub. Instr. Bien. Rep. for 1878-1880, 13:127, 138-60.] Supplementary report on the food of the thrush family. III. Hort. Soc. Trans. for 1880, n.s., 14:106-26. A few notes on the food of the meadow lark. Ill. Hort. Soc. Trans. for 1880, n.s., 14:234~-7. The English sparrow in Illinois. Am. Nat. 15(5) : 392-3. Report of the Director of the State Laboratory of Natural History, for the two years ending June 30, 1881, and June 30, 1882. 12 pp. [Also in Ill. Supt. Pub. Instr. Bien. Rep. for 1880-1882, 14:Lx—Lxx1.] LITERATURE CITED 223 18824. The ornithological balance-wheel. III. 1883a 1883b 1883c. 1883d. Notes on economic ornithology. 1884. 1886a Hort. Soc. Trans. for 1881, n.s., 15: 120-31. . The regulative action of birds upon insect oscillations. Ill. Lab. Nat. Hist. Bul. 1(6) : 3-32. . The food of the smaller fresh-water fishes. Ill. Lab. Nat. Hist. Bul. 1(6) :65-94, The first food of the common white- fish. (Coregonus clupeiformis, Mitch.) Ill. Lab. Nat. Hist. Bul. 1(6) :95-109. Ill. Hort. Soe. “Frans. for n.S., 16:60-71. A catalogue of the native fishes of Illinois. Ill. Fish Commrs. Rep. for 1884:60-89. . Miscellaneous essays on economic entomology by the State Entomologist and his entomological assistants. Springfield, Illinois. 130 pp. 1882, 18864. Report of the Director of the State 1887. 1888. 1889. [1890.] 1891. 1894. 1895a 1895. 1896. Laboratory of Natural History. III. Supt. Pub. Instr. Bien. Rep. for 1884— 1886, 16:LxX—LxII. Report of the Director of the State Laboratory of Natural History, Champaign, Illinois. June 8, 1887. 4 pp. Biennial report of the Director of the State Laboratory of Natural His- tory, Champaign, Illinois. October 31, 1888. 10 pp. Fifteenth report of the State Ento- mologist on the noxious and_ benefi- cial insects of the state of Illinois . . . for the years 1885 and 1886. Springfield. vi+ 115 pp. Biennial report of the Director of the Illinois State Laboratory of Nat- ural History, Champaign, Illinois, 1889-1890. 5 pp. On the common white grubs. nosterna and Cyclocephala). Ent. Rep. 17:30-53. Illinois State Laboratory of Natural History, Champaign, Ill. Biennial Report of the Director, 1893-1894. Chicago. 36 pp.+17 pls. . Illinois State Laboratory of Natural History, Champaign, Illinois. Bien- nial Report of the Director. 1893- 1894. Ill. Fish Commrs. Rep. for 1892-1894:39-52+4 pls. Nineteenth report of the State Ento- mologist on the noxious and benefi- cial insects of the state of Illinois. Eighth report of S. A. Forbes, for the years 1893 and 1894. Springfield. 206 pp. Illinois State Laboratory of Natural History, Urbana, Ill. Biennial Re- port of the State Laboratory and Spe- cial Report of the University Biolog- ical Experiment Station. 1895-1896, Springfield. 31 pp.+20 pls, (Lach- Ill. 224 1900. 1901. 1907a. 1907). 1907c. 1908. 1909. 1912a. 1912). 1913. 1915. 1919a. [1919] d. 1923. 1925. 1928. I-ttinois NAtrurRAL History Survey BULLETIN Recent work on the San Jose scale in Illinois. Ill. Ent. Rep. 21:1-47. Illinois State Laboratory of Natural History. Biennial Report of the Di- rector for 1899-[19]00. Urbana. 12 pp- On the local distribution of certain Illinois fishes: an essay in statistical ecology. Ill. Lab. Nat. Hist. Bul. 7(8) : 273-303 +15 maps, 9 pls. An ornithological cross-section of Illinois in autumn. Ill. Lab. Nat. Hist. Bul. 7(9) :305-35. History of the former state natural history societies of Illinois. Science, n.s., 26(678) :892-8. The mid-summer bird life of IIli- nois: a statistical study. Am. Nat. 42 (500) :505-19. The Illinois State Laboratory of Nat- ural History and the Illinois State Entomologist’s Office. Ill. Acad. Sci. Trans. for 1909, 2:54-67. What is the matter with the elms in Illinois? Ill. Ag. Exp. Sta. Bul. 154:3-22. The native animal resources of the state. Ill. Acad. Sci. Trans. for 1912, 5:37-48. The midsummer bird life of Illinois: a statistical study. Ill. Lab. Nat. Hist. Bul. 9(6) :373-85. The insect, the farmer, the teacher, the citizen, and the state. An ad- dress delivered December 13, 1910, to a joint meeting of teachers and farmers at Normal, III. Illinois State Laboratory of Natural History, Ur- bana. 14 pp. Forest and stream in Illinois. Illi- nois Department of Registration and Education, Springfield. 15 pp. Recent forestry survey of Illinois. Ill. Hort. Soc. Trans. for 1918, n.s., 52:103-10. The State Natural History Survey. Ill. Blue Book for 1923-1924 :384~7. The lake as a microcosm. IIl. Nat. Hist. Surv. Bul. 15(9) :537—50. The biological survey of a river sys- tem—its objects, methods, and _ re- sults. Ill. Nat. Hist. Surv. Bul. 17 (7) :277-84. Forbes, Stephen A., and Alfred O. Gross 1921. The orchard birds of an IIlinois sum- mer. Ill. Nat. Hist. Surv. Bul. 14(1): 1-8+6 pls. The numbers and local distribution in summer of Illinois land birds of the open country. Ill. Nat. Hist. Surv. Bul. 14(6) :187-218+36 pls. On the numbers and local distribu- tion of Illinois land birds of the open country in winter, spring, and fall. Ill. Nat. Hist. Surv. Bul. 14(10) : 397- 453. Forbes, Stephen A., and Robert B. Miller 1920. Concerning a forestry survey and a Forbes, Richa [1908.] 1913. 1919. Forsberg, Junius L. 1947. 1955a. 1955. 1957. Forsberg, J. L., and G. H. Boewe 1945. Francis, 1859a. 1859. Frison, 1929. 1931. 1933, 1935, 1937. 1938. 1940. 1942a. Vol. 27, Art. 2 forester for Illinois. Ill. Nat. Hist. Surv. Cire. 8. (Forestry Cire. 1.) 7 pp. Stephen Alfred, and Robert Earl rdson The fishes of Illinois. Illinois State Laboratory of Natural History, [Ur- — bana]. cxxxit+357 pp.+separate at- — las containing 102 maps. Bs Studies on the biology of the upper Illinois River. Ill. Lab. Nat. Hist. Bul. 9(10) :481-574+21 pls. Some recent changes in Illinois River biology. Ill. Nat. Hist. Surv. Bul. 13(6) :139-56. When we're sick. [Two virus dis- eases of carnations.] Here We Grow 2(3) :[22-3]. Fusarium disease of gladiolus: its — causal agent. Ill. Nat. Hist. Surv. Bul. 26(6) :447-503. The use of insecticides as corm and soil treatments for control of bac- terial scab of gladiolus. U. S. Dept. Ag. Plant Dis. Reptr. 39(2) :106-14. A vascular form of the Curvularia disease of gladiolus. Phytopathology 47(1) :12. Violet scab found in Illinois for the first time. U. S. Dept. Ag. Plant Dis. Reptr. 29(25/26) :680. S., Editor Illinois Natural History Society [1858]. Ill. Ag. Soc. Trans. for 1857— 1858, 3:637-61. Illinois Natural History [1859]. . Il. Ag». Sor 1857-1858, 3:662-85. Theodore H. Fall and winter stoneflies, or Plecop- tera, of Illinois. Ill. Nat. Hist. Surv. Bul. 18(2) :345-409. State Natural History Survey. IIl. Blue Book for 1931-1932:387-400. Economic problems of Illinois’ fields, forests, and streams solved by Nat- ural History Survey. Ill. Blue Book for 1933-1934:477-92. The stoneflies, or Plecoptera, of IlIli- Trans. for nois. Ill. Nat. Hist. Surv. Bul. 20(4): — 281-471. Studies of Nearctic aquatic insects. II. Descriptions of Plecoptera. Ill. Nat. Hist. Surv. Bul. 21(3) :78-99. Advances in the renewable natural resources program of Illinois. Ill. Acad. Sci. Trans. for 1938, 31(1): 19-34. New wildlife under way 5(1) 28-9, 16. Studies of North American Plecop- tera, with special reference to the fauna of Illinois. Ill. Nat. Hist. Surv. Bul. 22(2) :235-355. restoration in Illinois. program Ill. Cons. Society — December, 1958 1942b. The conservation research program of the Illinois Natural History Sur- vey. Ill. Acad. Sci. Trans. for 1942, 35 (1) :5-12. Galusha, O. B. 1881. [Comment following presentation of “A few notes on the food of the meadow lark,’ by S. A. Forbes.] III. Hort. Soc. Trans. for 1880, 14:238. Garman, H. 1890. A preliminary report on the ani- mals of the Mississippi bottoms near Quincy, Illinois, in August, 1888. Part I. Ill. Lab. Nat. Hist. Bul. 3(9) :123-84. Garman, Philip 1917. The Zygoptera, or Illinois. Ill. Lab. Nat. 12 (4) :411-587+ 16 pls. Gates, Frank Caleb damsel-flies, of Hist. Bul. 1912. The vegetation of the beach area in northeastern Illinois and _ southeast- ern Wisconsin. III. Lab. Nat. Hist. Bul. 9(5) :255-372 + 20 pls. Glasgow, Robert D. 1916. Phyllophaga Harris (Lachnosterna Hope): a revision of the synonymy, and one new name. III. Lab. Nat. Hist. Bul. 11(5) :365-79. Gleason, Henry Allan 1910. The vegetation of the inland sand deposits of Illinois. Ill. Lab. Nat. Hist. Bul. 9(3) :23-174+ 20 pls. Goding, F. W. 1885. Biographical sketch of William Le Baron, late State Entomologist of Illinois. Ent. Am. 1(7) :122-5. 1889. A pen sketch of Cyrus Thomas, third State Entomologist. II]. Hort. Soe. Trans. for 1888, n.s., 22:106-8. Gow, A. M. 1861. Natural history in schools. Ill. Nat. Hist. Soc. Trans. 2nd ed. Ser. 1, 1: 87-97. Greeley, Horace 1870. Insect depredations. Bot. 2(10) :301. Gross, Alfred O. 1921. The dickcissel (Spiza americana) of the Illinois prairies. Auk 38(1) :1-26; 38 (2) :163-84. Hall, R. Clifford, and O. D. Ingall 1911. Forest conditions in Illinois. II]. Lab. Nat. Hist. Bul. 9(4) :175-253 + 16 pls. Hansen, Donald F. 1951. Biology of the white crappie in IIli- nois. Ill. Nat. Hist. Surv. Bul. 25(4) :211-65. Hanson, Harold C. 1949a. Trapping and geese. Ill. Nat. Notes 20. 8 pp. 1949b. Methods of determining age in Can- ada geese and other waterfowl. Jour. Wildlife Mgt. 13(2) :177-83. Am. Ent. and handling Canada Hist. Surv. Biol. LITERATURE CITED 225 1953a. Aids for the exploration of the avian cloaca for characters of sex and age. Jour. Wildlife Mgt. 17(1) :89-90. 1953b. Inter-family dominance in Canada geese. Auk 70(1):11-6. 1954. Apparatus for the study of incu- bated bird eggs. Jour. Wildlife Mgt. 18 (2) :191-8. A three-year survey of Ornithofilaria sp. microfilariae in Canada geese. Jour. Parasitol. 42(5) :543. Hanson, Harold C., and Campbell Currie 1957. The kill of wild geese by the na- tives of the Hudson—James Bay re- gion. Arctic 10(4) :211-29. Hanson, Harold C., and Richard E. Griffith 1956. 1952. Notes on the south Atlantic Canada goose population. Bird-Banding 23(1) :1-22. Hanson, Harold C., and Charles W. Kossack 1950. “Flying acrobat” gains in Illinois: Doves on upswing but need manag- ing. Outdoors in Ill. 16(3) :30-1. 1957a. Methods and criteria for aging incu- bated eggs and nestlings of the mourning dove. Wilson Bul. 69(1): 91-101. 1957b. Weight and body-fat relationships of mourning doves in Illinois. Jour. Wildlife Mgt. 21(2) :169-81. Hanson, Harold C., Norman D. Levine, and Virginia Ivens 1957. Coccidia (Protozoa: Eimeriidae) of North American wild geese and swans. Can. Jour. Zool. 35(6) :715- 33. Hanson, Harold C., Norman D. Levine, and Sidney Kantor 1956. Filariae in a wintering flock of Can- ada geese. Jour. Wildlife Mgt. 20 (1) :89-92. Hanson, Harold C., Norman D. Levine, Charles W. Kossack, Sidney Kantor, and Lewis J. Stannard 1957. Parasites of the mourning dove (Zenaidura macroura carolinensis) in Illinois. Jour. Parasitol. 43 (2) : 186-93. Hanson, Harold C., and Robert H. Smith 1950. Canada geese of the Mississippi fly- way, with special reference to an Illinois flock. Ill. Nat. Hist. Surv. Bul. 25(3) :67-210. Harris, Hubert A. 1932. Initial studies of American elm dis- eases in Illinois. Ill. Nat. Hist. Surv. Bul. 20(1) :1-70. Hart, Charles Arthur 1919. The Pentatomoidea of Illinois, with keys to the Nearctic genera. Ill. Nat. Hist. Surv. Bul. 13(7) :157-223 +6 pls. Hart, Charles A., and Henry Allan Gleason 1907. On the biology of the sand areas of Illinois. Ill. Lab. Nat. Hist. Bul. 7(7):137-272+1 map, 16 pls, 226 Hebard, Morgan 1934. The Dermaptera and Orthoptera of Illinois. Ill. Nat. Hist. Surv. Bul. 20(3) :125-279. Hempel, Adolph 1896. Descriptions of new species of Rotif- era and Protozoa from the Illinois River and adjacent waters. III. Lab. Nat. Hist. Bul. 4(10) :310-7+5 pls. 1899. A list of the Protozoa and Rotifera found in the Illinois River and adja- cent lakes at Havana, Ill. Ill. Lab. Nat. Hist. Bul. 5(6) :301-88. Hesselschwerdt, Robert E. 1942. Use of den boxes in wildlife restora- tion on intensively farmed areas. Jour. Wildlife Mgt. 6(1) :31-7. Himelick, E. B., and E. A. Curl 1955. Experimental transmission of the oak wilt fungus by caged squirrels. Phytopathology 45(11) :581-4. 1958. Transmission of Ceratocystis faga- cearum by insects and mites. U. S. Dept. Ag. Plant Dis. Reptr. 42(4): 538-45. Himelick, E. B., E. A. Curl, and Bert M. Zuckerman 1954. Tests on insect transmission of oak wilt in Illinois. U. S. Dept. Ag. Plant Dis. Reptr. 38(8) :588-90. Himelick, Eugene B., Richard D. Schein, and E. A. Curl 1953. Rodent feeding on mycelial pads of the oak wilt fungus. U. S. Dept. Ag. Plant Dis. Reptr. 37(2) :101-3. Hoff, C. Clayton 1949. .The pseudoscorpions of Illinois. III. Nat. Hist. Surv. Bul. 24(4) :413-98. Hoffman, Paul F. 1953. Oak wilt fungus pathogenic on Quercus chrysolepis and Quercus agrifolia. U. S. Dept. Ag. Plant Dis. Reptr. 37(10) :527. Hoffman, Paul F., and Bert M. Zuckerman 1954. Oak wilt fungus labeled with C*. Science, n.s., 120(3107) :106-8. Hoffmeister, Donald F., and Carl O. Mohr 1957. Fieldbook of Illinois mammals. III. Nat. Hist. Surv. Man. 4. 233 pp. Holder, R. H. 1861a. Taxidermy. Directions for collecting and preserving specimens in orni- thology. Ill. Ag. Soc. Trans. for 1859-1860, 4:597-603. 18614. Birds of Illinois. Catalogue. Ill. Ag. Soc. Trans. for 1859-1860, 4: 605-13. Hood, J. Douglas 1908. New genera and species of Illinois Thysanoptera. II]. Lab. Nat. Hist. Bul. 8(2) :361-79. Hottes, Frederick C., and Theodore H. Frison 1931. The plant lice, or Aphiidae, of IIli- nois. Ill. Nat. Hist. Surv. Bul. 19(3): 123-447. I-Ltrnois NaturAL History SurvEY BULLETIN Vol. 27, Art. 2 Hovey, Charles E. 1859. State Normal University. Ill. Ag. Soc. Trans. for 1857-1858, 3:398—-402. Howard, L. O. 1932. Biographical memoir of Stephen Al- fred Forbes 1844-1930. Natl. Acad. Sci. Biog. Mem. 15(1) :1-54. The insect menace. D. Appleton- Century Company, New York. 347 pp- Hubbs, Carl L. 1930. Fishery research in Michigan. Am. Fish. Soc. Trans. for 1930, 60:182-6. Illinois General Assembly 1861. Private laws of the State of Illinois, passed by the Twenty-Second Gen- eral Assembly, . . . Springfield. 760 1933. pp. Public laws of the State of Illinois, passed by the Twenty-Fifth General Assembly . . . Springfield. 205 pp. Public laws of the State of Illinois, passed by the Twenty-Sixth General Assembly, . . . Springfield. 434 pp. Public laws of the State of Illinois, passed by the Twenty-Seventh Gen- eral Assembly, . . . Springfield. 800 + vii pp. Laws of the State of Illinois: passed by the Thirtieth General Assembly. . . . Springfield. 229-+iv pp. Laws of the State of Illinois: enacted by the Thirty-First General Assem- bly. . . . Springfield. 326+ xii pp. Laws of the State of Illinois, enacted by the Thirty-Fourth General As- sembly, .. . Springfield. 268+ vi pp. Laws of the State of Illinois, enacted by the Thirty-Fifth General Assem- bly, .. . Springfield. 338 pp. Laws of the State of Illinois enacted by the Fiftieth General Assembly at the regular biennial session. . . Springfield. xxiiit+ 844 pp. Laws of the State of Illinois enacted by the Seventieth General Assembly at the regular biennial session . . . Springfield. 2 vols. 2,976 pp. Illinois House of Representatives 1957. Journal of the Illinois House of Rep- resentatives of the Seventieth Gen- eral Assembly of the State of Illinois, No. 38, for Tuesday, April 9, 1957. 42 pp. Johnson, Benjamin F. 1861. Report on farms and nurseries. III. Ag. Soc. Trans. for 1859-1860, 4:83- 95. Jordan, David S. 1878. A catalogue of the fishes of IIlinois. Ill. Lab. Nat. Hist. Bul. 1(2) :37—70. Jordan, James S., and Frank C. Bellrose 1867. 1869. 1872. 1957. 1950. Shot alloys and lead poisoning in waterfowl. N. Am. Wildlife Conf. Trans. 15:155-68. 1951. Lead poisoning in wild waterfowl. ere Ca ek ee 6 ee Serie Po" December, 1958 Ill. Nat. Hist. Surv. Biol. Notes 26. 27 pp. Kennicott, John A., Corresponding Secretary 1855. Transactions of the Illinois State Agricultural Society: . . . 1853-1854. Springfield. viii 612+ iv pp. Kennicott, John A., Editor 1857. Transactions of the Illinois State Agricultural Society, . . . 1856-1857. Springfield. xvi+ 684 pp.+14 pls. Kennicott, Robert 1855. Catalogue of animals observed in Cook County, Illinois. Ill. Ag. Soc. Trans. for 1853-1854, 1:577-95. Knight, Harry H. 1941. The plant bugs, or Miridae, of Illi- nois. Ill. Nat. Hist. Surv. Bul. 22(1) : 1-234. Kofoid, C. A. 1897. Plankton studies. I. Methods and ap- paratus in use in plankton investiga- tions at the biological experiment station of the University of Illinois. Ill. Lab. Nat. Hist. Bul. 5(1) :1-26 +7 pls. Plankton studies. II. On Pleodorina illinoisensis, a new species from the plankton of the Illinois River. III. Lab. Nat. Hist. Bul. 5(5) :273-300. Plankton studies. III. On Platydorina, a new genus of the family Volvoci- dae, from the plankton of the Illinois River. Ill. Lab. Nat. Hist. Bul. 5(9) :419-40+1 pl. Plankton studies. IV. The plankton of the Illinois River, 1894-1899, with introductory notes upon the hydrog- raphy of the Illinois River and its basin. Part I. Quantitative investi- gations and general results. Ill. Lab. Nat. Hist. Bul. 6(2) :95-635+-50 pls. Plankton studies. V. The plankton of the Illinois River, 1894-1899. Part IJ. Constituent organisms and their seasonal distribution. II]. Lab. Nat. Hist. Bul. 8(1) :3-360. Kossack, Charles W. 1898. 1899, 1903. 1908. 1952. Banding nestling mourning doves. Bird-Banding 23(1) :28-9. 1955. Mourning dove banding project. In- land Bird Banding News 27(1) :1-8. Kossack, Charles W., and Harold C. Hanson 1953. Unisexual broods of the mourning dove. Jour. Wildlife Mgt. 17(4): 541. 1954. Fowlpox in the mourning dove. Am. Vet. Med. Assn. Jour. 124(924): 199-201. Langlois, T. H. 1937. Recommendations for improving bass fishing in Ohio. N. Am. Wildlife Conf. Trans. 2:649-52. Lapham, I. A. 1857a. Catalogue of the plants of the state of Illinois. Ill. Ag. Soc. Trans. for 1856-1857, 2:492-550. LITERATURE CITED 227, 1857b. The native, naturalized and culti- vated grasses of the state of Illinois. Ill. Ag. Soc. Trans. for 1856-1857, 2:551-613. Large, Thomas [1903.] A list of the native fishes of Illinois, with keys. Append. to Ill. Fish Commrs. Rep. 1900-1902. 30 pp. Larimore, R. Weldon 1949. Changes in the cranial nerves of the paddlefish, Polyodon spathula, ac- companying development of the ros- trum. Copeia 1949(3) :204-12. Gametogenesis of Polyodon spathula (Walbaum): a basis for regulation of the fishery. Copeia 1950(2) :116- 24. Home pools and homing behavior of smallmouth black bass in Jordan Creek. II]. Nat. Hist. Surv. Biol. Notes 28. 12 pp. Minnow productivity in a small IIli- nois stream. Am. Fish. Soc. Trans. for 1954, 84:110-6. Ecological life history of the war- mouth (Centrarchidae). Ill. Nat. Hist. Surv. Bul. 27(1) :1-83. Larimore, R. Weldon, Quentin H. Pickering, and Leonard Durham 1952. An inventory of the fishes of Jordan Creek, Vermilion County, Illinois. Ill. Nat. Hist. Surv. Biol. Notes 29. 26 pp. Le Baron, William 1855. Observations upon some of the birds of Illinois most interesting to the ag- riculturist. Ill. Ag. Soc. Trans. for 1853-1854, 1:559-65. First annual report on the noxious insects of the state of Illinois. Springfield. Pp. 1-96. [II]. Ent. Rep. 2.] Second annual report on the noxious insects of the state of Illinois. Springfield. Pp. 97-166+ index. [IIl. Ent. Rep. 3.] Third annual report on the noxious insects of the state of Illinois. Springfield. Part 1, pp. 167-202. Part 2. 37 pp. [Ill. Ent. Rep. 4.] Outlines of entomology, published in connection with the author’s annual reports upon injurious insects. Part 1. Including the order of Coleoptera. Ill. Ent. Rep. 5. xvui+199 pp. Leigh, W. Henry 1940. Preliminary studies on parasites of upland game birds and fur-bearing mammals in Illinois. Ill. Nat. Hist. Surv. Bul. 21(5) :185-94. Leopold, Aldo 1950. 1952. 1955. Sie 1871. 1872. 1873. 1874. 1931. Report on a game survey of the north central states. Sporting Arms and Ammunition Manufacturers’ Insti- tute, Madison, Wis. 299 pp. 1933. Game management. Charles Scrib- ner’s Sons, New York. xxit481 pp. 228 I-ttinois NaturAL History SurvEY BULLETIN Levine, Norman D. 1952. Eimeria magnalabia and Tyzzeria sp. (Protozoa:Eimeriidae) from the Canada goose. Cornell Vet. 42(2): 247-52. A review of the coccidia from the avian orders Galliformes, Anseri- formes and Charadriiformes, with descriptions of three new species. Am. Midland Nat. 49(3) :696-719. Leucocytozoon in the avian order Columbiformes, with a description of L. marchouxi Mathis and Leger 1910 from the mourning dove. Jour. Pro- tozool. 1(2) : 140-3. Levine, Norman D., and Harold C. Hanson 1953. Blood parasites of the Canada goose, Branta canadensis interior. Jour. Wildlife Mgt. 17(2):185-96+1 pl. Lill, Althea " 1942. Natural History Survey Library, an- nual report, May 1, 1941-May 31, 1942. 6 pp. [Not published, but available in University of Illinois Library, Urbana.] Lincoln, Frederick C. 1924. Returns from banded birds, 1920 to 1923. U. S. Dept. Ag. Dept. Bul. 1268. 56 pp. Lord, Rexford D., Jr. 1958. The importance of juvenile breeding to the annual cottontail crop. N. Am. Wildlife Conf. Trans. 23:269-75. Loucks, W. E. 1894. The life history and distribution of the prothonotary warbler in Illinois. Ill. Lab. Nat. Hist. Bul. 4(3) :10-35. Low, Jessop B., and Frank C. Bellrose 1944. The seed and vegetative yield of waterfowl food plants in the Illinois River valley. Jour. Wildlife Met. 8(1):7-22+1 pl. Lucas, Clarence R. 1939. Game fish management. Am. Fish. Soc. Trans. for 1938, 68:67-74. Malloch, J. R. 1915. The Chironomidae, or midges, of Illinois, with particular reference to the species occurring in the Illinois River. Ill. Lab. Nat. Hist. Bul. 10(6) :275-543+24 pls. A preliminary classification of Dip- tera, exclusive of pupipara, based upon larval and pupal characters, with keys to imagines in certain fam- ilies. Part I. Ill. Lab. Nat. Hist. Bul. 12(3) :161-409+30 pls. The North American species of the genus Tiphia (Hymenoptera, Acu- leata) in the collection of the Illinois State Natural History Survey. Ill. Nat. Hist. Surv. Bul. 13(1):1-24+1 pl. A new species of Erythroneura (Ty- phlocybidae, Hem.-Hom.). Brooklyn Ent. Soc. Bul., n.s., 16(1) : 25. 1955. 1954. 1917. 1918. Vol. 27, Art. 2 Mann, Roberts, Editor 1956. Policies of the Department of Con- servation: a report by the Conserva- tion Advisory Board. State of Illi- nois, Springfield. 36 pp. Markus, Henry C. 1932. The extent to which temperature changes influence food consumption in largemouth bass (Huro floridana). Am. Fish. Soc. Trans. for 1932, 62 :202-10. Marquardt, William C., and Thomas G. Scott 1952. It’s in the bag. Ill. Wildlife 7(2): 4-5. Marshall, Helen E. 1956. Grandest of enterprises: Illinois State Normal University, 1857-1957. Illi- nois State Normal University, Nor- mal. xiiit+355 pp. McAtee, W. L. 1917. Life and writings of Professor F. E. L. Beal. Auk 34(3) :243-64. Notes on a collection of Erythroneura and Hymetta (Eupterygidae) chief- ly from Illinois, with descriptions of new forms. III]. Nat. Hist. Surv. Bul. 15(2) :39-44. Notes on Homoptera from Illinois, with descriptions of new forms, chiefly Eupteryginae. II]. Nat. Hist. Surv. Bul. 16(3) :127-36. McDougall, Walter B. 1924. 1926. 1917. Some edible and poisonous mush- rooms. Ill. Lab. Nat. Hist. Bul. 11(7) :413-555. Mead, S. B. 1846. Catalogue of plants growing spon- taneously in the state of Illinois, the principal part near Augusta, Han- cock County. Prairie Farmer 6(1): 35-6; 6(2):60; 6(3):93; 6(4) :119- 22. Middleton, Nettie F 1878. A new species of Aphis, of the genus Colopha. Ill. Lab. Nat. Hist. Bul. IM(2)e2073 Miller, Robert B. 1923. First report on a forest survey of Illinois. Ill. Nat. Hist. Surv. Bul. 14(8) :291-377+27 pls. Miller, Robert Barclay, and L. R. Tehon 1929. The native and naturalized trees of Illinois. Ill. Nat. Hist. Surv. Bul. 18 (1) :1-339. Minier, George W. 1865. Cultivation of forest trees. Ill. Ag. Soc. Trans. for 1861-1864, 5:779-80. 1868. On the cultivation of forest trees. Ill. Ag. Soc. Trans. for 1865-1866, 6:279-82. Mohr, Carl O. 1943a. Illinois income. Ill. 22(7) :505-37. 1943b. A comparison of North American distribution and Hist. Surv. Bul. furbearer Nat. December, 1958 small-mammal censuses. Am. Mid- land Nat. 29(3) :545-87. 1947a. Table of equivalent populations of North American small mammals. Am. Midland Nat. 37(1) : 223-49. 1947b. Major fluctuations of some Illinois mammal populations. Ill. Acad. Sci. Trans. for 1947, 40:197-204. Moore, J. Percy 1901. The Hirudinea of Illinois. Il]. Lab. Nat. Hist. Bul. 5(12):479-92+6 pls. Mulvihill, Wm. F., and L. D. Cornish 1930. Flood control report: an enginecring study of the flood situation in the state of Illinois. Illinois Division of Waterways, Springfield. 402 pp. Mygatt, E. G. 1855. Bark louse of the apple tree. III. Ag. Soc. Trans. for 1853-1854, 1: 514-7. Needham, James G., and Charles A. Hart 1903. The dragon-flies (Odonata) of IIli- nois, with descriptions of the im- mature stages. Part I. Petaluridae, Aeschnidae, and Gomphidae. Ill. Lab. Nat. Hist. Bul. 6(1) :1-94-+1 pl. Nelson, E. W. 1876. A partial catalogue of the fishes of Illinois. Ill. Mus. Nat. Hist. Bul. 1(1) 233-52. Nevin, James 1898. Artificial propagation versus a close season for the Great Lakes. Am. Fish. Soc. Proc. 27:17-25. O’Donnell, D. John 1935. Annotated list of the fishes of IIli- nois. Ill. Nat. Hist. Surv. Bul. 20(5) : 473-500. Ordway, O. 1857. Treatise on the advantages to be de- rived from the cultivation of flowers. Ill. Ag. Soc. Trans. for 1856-1857, 2:401-6. Pietsch, Lysle R. 195+. White-tailed deer populations in IIli- nois. Ill. Nat. Hist. Surv. Biol. Notes 34. 22 pp. 1957. The beaver in Illinois. Ill. Acad. Sci. Trans. for 1956, 49:193-201. Pillsbury, William L., Corresponding Secre- tary 1892. Sixteenth report .. . of the Board of Trustees of the University of Illi- nois . . . for the two years ending September 30, 1892. 296 pp. Seventeenth report ... of the Board of Trustees of the University of IIli- nois . .. for the two years ending September 30, 1894. 338 pp. Eighteenth report ... of the Board of Trustees of the University of IIli- nois . . . for the two years ending September 30, 1896. 334 pp.+20 pls. Nineteenth report . . . of the Board of Trustees of the University of Illi- 1894. 1896. 1898. LITERATURE CITED 229 am nois . . . for the two years ending September 30, 1898. 363 pp. Twentieth report... of the Board of Trustees of the University of IIli- nois ... for the two years ending September 30, 1900. xix+384 pp. Twenty-first report... of the Board of Trustees of the University of IIli- nois . . . for the two years ending September 30, 1902. xxiit+383 pp. Twenty-third report ... of the Board of Trustees of the University of IIli- nois . . . for the two years ending September 30, 1906. xxv +498 pp. Powers, Edwin B. 1918. A collecting bottle especially adapted for the quantitative and qualitative determination of dissolved gases, particularly very small quantities of oxygen. Ill. Lab. Nat. Hist. Bul. 11(10) :577-8. Pratten, Henry 1855. Catalogue of the birds of Illinois. Ill. Ag. Soc. Trans. for 1853-1854, 1:598-609. Reynolds, John P., Corresponding Secretary 1901. 1902. 1906. 1861. ‘Transactions of the Illinois State Ag- ricultural Society ... Vol. IV, 1859- 1860. Springfield. 698+ iy pp. 1865. Transactions of the Illinois State Ag- ricultural Society . .. Vol. V, 1861- 1864. Springfield. 992+ vii pp. [Reynolds, John P.] 1866. Address of the president. Ill. Hort. Soc. Trans. for 1865, 10:7-10. Reynolds, John P., Corresponding Secretary 1868. Transactions of the Illinois State Agricultural Society . Vol. VI, 1865-1866. Springfield. xxxv+ 666 + XXIV pp. Richardson, Robert E. 1921. The small bottom and shore fauna of the middle and lower Illinois River and its connecting lakes, Chilli- cothe to Grafton: its valuation; its sources of food supply; and its rela- tion to the fishery. II]. Nat. Hist. Surv. Bul. 13(15) :363—522. 1925a. Changes in the small bottom fauna of Peoria Lake, 1920 to 1922. Ili. Nat. Hist. Surv. Bul. 15(5) :327-88. 1925h. Illinois River bottom fauna in 1923. Ill. Nat. Hist. Surv. Bul. 15(6) :391- 422. The bottom fauna of the middle IIli- nois River, 1913-1925: Its distribu- tion, abundance, valuation, and index value in the study of stream pollu- tion. Ill. Nat. Hist. Surv. Bul. 17(12): 387-475. Ridgway, Robert 1881. A revised catalogue of the birds ascertained to occur in Illinois. II. Lab. Nat. Hist. Bul. 1(4) : 163-208. The ornithology of Illinois. Part 1. 1928. 1889. 230 Descriptive catalogue. Vol. I. Spring- field. viii+ 520 pp. 1895. The ornithology of Illinois. Part 1. Descriptive catalogue. Vol. II. Springheld. 282 pp. 1901. The birds of north and middle Amer- ica: A descriptive catalogue of the higher groups, genera, species, and subspecies of birds known to occur in North America, from the Arctic lands to the Isthmus of Panama, the West Indies and other islands of the Car- ibbean Sea, and the Galapagos Ar- chipelago. U.S. Natl. Mus. Bul. 50. Part 9b. 3x75" pp: Riley, Charles V. 1866. Entomological notes. Prairie Farmer, n.s., 17(25) :432. Riley, Charles V., Editor 1869 In memoriam. [Brief biography of -70. Benjamin D. Walsh.] Am. Ent. 2(3): 65-8. Robertson, William B., Jr. 1958. Investigations of ring-necked pheas- ants in Illinois. Ill. Dept. Cons. Tech. Bul. 1. 138 pp. Roe, R., and Henry Schmidt 1897. Report of the Commissioners. III. Fish Commrs. Rep. 1894-1896. 21 pp. Ross, Herbert H. 1937. Studies of Nearctic aquatic insects. I. Nearctic alder flies of the genus Sialis (Megaloptera, Sialidae). Ill. Nat. Hist. Surv. Bul. 21(3): 57-78, 98-9. 1944. The caddis flies, or Trichoptera, of Illinois. Ill. Nat. Hist. Surv. Bul. 23 (1) :1-326. 1947. The mosquitoes of Illinois (Diptera, Culicidae). Ill. Nat. Hist. Surv. Bul. 24(1) :1-96. 1956. Evolution and classification of the mountain caddisflies. Illinois Press, Urbana. Sargent, C. S. 1889. Portions of the journal of André Michaux, botanist, written during his travels in the United States and Can- ada, 1785 to 1796. With an intro- duction and explanatory notes. Am. Phil. Soc. Proc. 26(129) :1-145. Schacht, Frederick William University of 213 pp. 1897. The North American species of Diaptomus. Il. Lab. Nat. Hist. Bul. 5(3) :97-223. 1898. The North American Centropagidae belonging to the genera Osphranti- cum, Limnocalanus, and Epischura. Ill. Lab. Nat. Hist. Bul. 5(4) :225-70. Schenck, Norman C., and J. C. Carter 1954. A fungistatic substance extracted from vitrain. Science, n.s., 119(3085) : 213-4. Scott, Thomas G. 1943. Some food coactions of the northern plains red fox. Ecol. Monog. 13(4): 427-79. ILttinois NATURAL History SuRVEY BULLETIN Vol. 27, Art. 2 1947. Comparative analysis of red fox feeding trends on two central Iowa areas. lowa Ag. Exp. Sta. Res. Bul. 353 :427-87. 1955. An evaluation of the red fox. IIl. Nat. Hist. Surv. Biol. Notes 35. 16 pp. 1957. Legal protection for hawks and owls in Illinois. Ill. Wildlife 12(2) :[3-5]. Scott, Thomas G., and Willard D. Klimstra 1954. Report on a visit to quail manage- ment areas in southeastern United States. Ill. Wildlife 9(3) :5-9. 1955. Red foxes and a declining prey pop- ulation. South. Ill. Univ. Ser. 1. 123 pp. Sharpe, Richard W. 1897. Contribution to a knowledge of the North American fresh-water Ostra- coda included in the families Cythe- ridae and Cyprididae. Ill. Lab. Nat. Hist. Bul. 4(15):414-84+10 pls. Shelford, Victor E. 1917. An experimental study of the effects of gas waste upon fishes, with espe- cial reference to stream pollution. II]. Lab. Nat. Hist. Bul. 11(6) :381—412. 1918a. Equipment for maintaining a flow of oxygen-free water, and for control- ling gas content. Ill. Lab. Nat. Hist. Bul. 11(9) :573-5. 1918b. Ways and means of measuring the dangers of pollution to fisheries. Ill. Nat. Hist. Surv. Bul. 13(2) : 25-42. Shelford, V. E., and W. P. Flint 1943. Populations of the chinch bug in the upper Mississippi valley from 1823 to 1940. Ecology 24(4) :435—-55. Shelford, V. E., and R. E. Yeatter Monog. 1955. Some suggested relations of prairie chicken abundance to physical fac- tors, especially rainfall and solar radiation. Jour. Wildlife Mgt. 19(2) : 233-42. : Short, C. W. 1845. Observations on the botany of Illi- nois, more especially in reference to the autumnal flora of the prairies. West. Jour. Med. and Surg., ns., 3:185-98. [Typed copy made at the University of Illinois from volume borrowed from library of St. Louis Medical Society. ] Simmons, Marguerite 1952. Natural History Survey Library, an- nual report, July 1, 1951-June 30, 1952. 5 pp. [Not published, but available in University of Illinois Library, Urbana. ] Smith, Frank 1895a. A preliminary account of two new Oligochaeta from Illinois. Ill. Lab. Nat. Hist. Bul. 4(5) :138-48. 1895. Notes on species of North American Oligochaeta. Ill. Lab. Nat. Hist. Bul. 4(8) :285-97. 1896. Notes on species of North American December, 1958 Oligochaeta. IJ. Ill. Lab. Nat. Hist. Bul. 4(14) :396-413+4 pls. 1900a. Notes on species of North American Oligochaeta. III. List of species found in Illinois, and descriptions of Illinois Tubificidae. Ill. Lab. Nat. Hist. Bul. 5(10) :441-58+2 pls. 1900b. Notes on species of North American Oligochaeta. IV. On a new lum- briculid genus from Florida, with additional notes on the nephridial and circulatory systems of Mesoporo- drilus asymmetricus Smith. Ill. Lab. Nat. Hist. Bul. 5(11) :459-78+1 pl. State natural history surveys. Science, n.s., 13(328) :566-8. Notes on species of North American Oligochaeta. V. The systematic re- lationship of Lumbriculus (Thino- drilus) inconstans (Smith). Ill. Lab. Nat. Hist. Bul. 7(5) : 45-51. Two new varieties of earthworms with a key to described species in Illinois. Il]. Lab. Nat. Hist. Bul. 10(8) :551-9+1 pl. A new North American oligochaete of the genus Haflotaxis. Ill. Nat. Hist. Surv. Bul. 13(3) :43-8+1 pl. An account of changes in the earth- worm fauna of Illinois and a de- scription of one new species. Ill. Nat. Hist. Surv. Bul. 17(10) :347-62. Records of spring migration of birds at Urbana, Illinois, 1903-1922. IIl. Nat. Hist. Surv. Bul. 19(2) :105-17. Smith, George W. 1927. History of Illinois and her people. Vol. 2. The American Historical Society, Inc., Chicago and New York. 496 pp. Smith, Lloyd L., Jr. 1949. Cooperative fishery survey of the upper Mississippi River. Am. Fish. Soc. Trans. for 1946, 76:279-82. Spooner, Charles S., Jr.. and Lee E. Yeager 1942. Potential wildlife habitat on the IIli- nois prairie and some problems of restoration. Jour. Wildlife Met. 6(1) :44—54. Stannard, Lewis J., Jr. 1957. The phylogeny and classification of the North American genera of the suborder ‘Tubulifera (Thysanop- tera). Ill. Biol. Monog. 25. 200 pp. Starrett, William C., and Paul G. Barnickol 1955. Efficiency and selectivity of commer- cial fishing devices used on the Mis- sissippi River. II]. Nat. Hist. Surv. Bul. 26(4) :325-66. Starrett, William C., and Perl L. McNeil, Jr. 1901. 1905. 1915. 1918. 1928. 1930. 1952. Sport fishing at Lake Chautauqua, near Havana, Illinois, in 1950 and 1951. Ill. Nat. Hist. Surv. Biol. Notes 30. 31 pp. Stessel, G. J., and Bert M. Zuckerman 1953. The perithecial stage of Chalara LITERATURE CITED 231 quercina in nature. 43(2) :65-70. Stoddard, Herbert L. 1931. ‘The bobwhite quail: its habits, pres- ervation and increase. Charles Scrib- ner’s Sons, New York. xxixt559 pp. Stout, G. L. 1930. New fungi found on the Indian corn plant in Illinois. Mycologia 22(6): 271-87. Surber, Eugene W. 1931. Sodium arsenite for controlling sub- merged vegetation in fish ponds. Am. Fish. Soc. Trans. for 1931, 61:143-7. Swingle, H. S., and E. V. Smith Phytopathology 1939. Increasing fish production in ponds. N. Am. Wildlife Conf. Trans. 4: 332-8. 1942. Management of farm fish ponds. Ala. Polytech. Inst. Ag. Exp. Sta. Bul. 254. 23 pp. Swingle, Roger U. 1942. Phloem necrosis: a virus disease of the American elm. U. S. Dept. Ag. Circ. 640. 8 pp. Tehon, Leo Roy 1924. Notes on the parasitic fungi of IIli- nois. Mycologia 16(4) :135—42. Three alfalfa diseases new to IIli- nois. Ill. Acad. Sci. Trans. for 1925, 18 :203-5. Methods and principles for interpret- ing the phenology of crop pests. IIl. Nat. Hist. Surv. Bul. 17(9) :321-46. Notes on the parasitic fungi of IIli- nois. Mycologia 25(4) :237—57. A monographic rearrangement of Lophodermium. Ill. Biol. Monog. 13 (4) :231-381. Rout the weeds! Why, when and how. Ill. Nat. Hist. Surv. Circ. 28. 34 pp. (Later issued as Circ. 34.) Notes on the parasitic fungi of IIli- nois. VI. Mycologia 29(4) :434—46. 1939a. Pleasure with plants. Ill. Nat. Hist. Surv. Circ. 32. 32 pp. Fungus growth cause of broom corn splotches. Broom and Broom Corn News 28(33) :13. Two new fungi on legumes. logia 31(5) :537-43. New species and taxonomic changes in the Hypodermataceae. Mycologia 31(6) :674—92. Fieldbook of native Illinois shrubs. Ill. Nat. Hist. Surv. Man. 3. 307 pp. A new mucor-like fungus from plant roots. Ill. Acad. Sci. Trans. for 1943, 36(2) :109-15. The drug plants of Illinois. Ill. Nat. Hist. Surv. Circ. 44. 135 pp. Fungistatic potencies of some fluori- nated p-benzoquinones. Science, n.s., 114 (2973) :663-4. Tehon, Leo R., Translator 1952a. True nature, causes, and sad effects 1925. 1928. 1933. 1935. 1937a. 1937. 19396. 1939c. Myco- 1939d. 1942. 1943. 1951a. 1951. bo w bo of the rust, the bunt, the smut, and other maladies of wheat, and of oats in the field. Part V of Alimurgia or Means of rendering less serious the dearths: proposed for the relief of the poor. Translated from the Ital- ian of Giovanni Targioni Tozzetti. Phytopathological Classics 9. xxiv +139 pp. Tehon, Leo Roy 1952b. Fungistatic capacities of aromatic fluorine compounds in relation to cloth-rotting fungi. Part 3. Fluori- nated anisoles, benzyls, benzoic acids, biphenyls, and toluenes. AF Tech. Rep. 6518(3). 46 pp. Wright Air Development Center, Wright-Patter- son Air Force Base, Ohio. 1954. Fungistatic capacities of aromatic fluorine compounds in relation to cloth-rotting fungi. Part 4. Fluori- nated phenols, benzyl alcohol, and biphenyls. AF Tech. Rep. 6518(4). 38 pp. Wright Air Development Center, Wright-Patterson Air Force Base, Ohio. Tehon, L. R., and G. H. Boewe 1939. Charcoal rot in Illinois. U. S. Dept. Ag. Plant Dis. Reptr. 23(19) :312-21. Tehon, L. R., and Eve Daniels 1925. Notes on the parasitic fungi of IIli- nois—II. Mycologia 17(6) :240-9. Tehon, L. R., and E. Y. Daniels 1927. Notes on the parasitic fungi of IIli- nois—III. Mycologia 19(3) :110-29. Tehon, Leo R., and Hubert A. Harris 1941. A chytrid inhabiting xylem in the Moline elm. Mycologia 33(1) :118- 29; Tehon, Leo R., and W. R. Jacks 1933. Smooth patch, a bark lesion of white oak. Jour. Forestry 31(4) :430-3. Tehon, L. R., C. C. Morrill, and Robert Graham 1946. Illinois plants poisonous to livestock. Ill. Ag. Exp. Sta. Cire. 599. 103 pp. Tehon, L. R., and G. L. Stout 1928. An ascomycetous leaf spot of cow- pea. Phytopathology 18(8) :701-4. 1929. Notes on the parasitic fungi of Illi- nois—IV. Mycologia 21(4) :180-96. Tehon, Leo R., and Sylvia Wolcyrz 1952a. Fungistatic capacities of aromatic fluorine compounds in relation to cloth-rotting fungi. Part 1. Fluori- nated quinones and phenols. AF Tech. Rep. 6518(1). 62 pp. Wright Air Development Center, Wright- Patterson Air Force Base, Ohio. 1952. Fungistatic capacities of aromatic fluorine compounds in relation to cloth-rotting fungi. Part 2. Fluori- nated phenols, nitrobenzenes, and anilines. AF Tech. Rep. 6518(2). 58 pp. Wright Air Development Telford, 1923. 1926. Thomas, 1857. 1859a. 1859b. 1861la. 1861d. 186l1c. 1865. 1876. [1878.] 1880. 1881. ILtinois NatrurAL History Survey BULLETIN Vol. 27, Art. 2 Center, Wright-Patterson Air Force Base, Ohio. Clarence J. Growth studies of certain bottom- land species in southern Illinois. III. Acad. Sci. Trans. for 1923, 16:210-3. Third report on a forest survey of Illinois. Ill. Nat. Hist. Surv. Bul. 16(1) :1-102. Cyrus Natural history of Illinois. Ill. Teacher 3(12) :424-5. The study of natural history. IIl. Ag. Soc. Trans. for 1857-1858, 3:665- 70. Orthoptera of Illinois. Ill. Ag. Soe. Trans. for 1857-1858, 3:682-5. Notes on Illinois insects. Ill. Ag. Soc. Trans. for 1859-1860, 4:631-49. Mammals of Illinois. Catalogue. Ill. Ag. Soc. Trans. for 1859-1860, 4:651- 61. Plan for a natural history survey. Ill. Ag. Soc. Trans. for 1859-1860, 4:663-5. Insects injurious to vegetation in IIli- nois. Ill. Ag. Soc. Trans. for 1861— 1864, 5:401-68. A list of the Orthoptera of Illinois. Ill. Mus. Nat. Hist. Bul. 1(1) :59-69. A list of the species of the tribe Aphidini, family Aphidae, found in the United States, which have been heretofore named, with descriptions of some new species. Ill. Lab. Nat. Hist. Bul. 1(2) :3-16. Temperature and rainfall as affect- ing the chinch bug—periodicity in its increase. Am. Ent., n.s., 1(10) :240-2. Tenth report of the State Entomolo- gist . . . on the noxious and beneficial insects of the state of Illinois. III. Ent. Rep. 10. 238+ vi pp. Thompson, David H. 1925. 1933a. 1933. 1941. Some observations on the oxygen re- quirements of fishes in the Illinois River. Ill. Nat. Hist. Surv. Bul. 15(7) :423-37. The migration of Illinois fishes. III. Nat. Hist. Surv. Biol. Notes 1. 25 pp. Mimeo. The finding of very young Polyodon. Copeia 1933(1) :31-3. The fish production of inland streams and lakes. Pp. 206-17 in A sympo- sium on hydrobiology. University of Wisconsin Press, Madison. ix+405 pPp- Thompson, David H., and George W. Bennett 1939a. 1939. 1939¢. Lake management reports. 2. Fork Lake near Mount Zion, Illinois. Ill. Nat. Hist. Surv. Biol. Notes 9. 14 pp. Lake management reports. 3. Lincoln Lakes near Lincoln, Illinois. Ill. Nat. Hist. Surv. Biol. Notes 11. 24 pp. Fish management in small artificial December, 1958 lakes. N. Am. Wildlife Conf. Trans. 4:311-7. Thompson, David H., and Francis D. Hunt 1930. The fishes of Champaign County: a study of the distribution and abun- dance of fishes in small streams. III. Nat. Hist. Surv. Bul. 19(1) :5-101. Thomson, G. H. 1913. Protection of the Am. Fish. Soc. 42:171-3. Trumbower, John A. 1934. Control of elm leaf spots in nurseries. Phytopathology 24(1) : 62-73. Turner, J. B. 1859. Microscopic Trans. for Ulffers, H. A. 1855. Mollusca of Trans. for undersized fish, Trans. for 1912, insects. Ill. Ag. Soc. 1857-1858, 3:644—50. southern Illinois. Ill. 1853-1854, Underwood, Lucien M. 1886. List of the described species of fresh water Crustacea from America, north of Mexico. II]. Lab. Nat. Hist. Bul. 2(5) :323-86. Van Cleave, Harley J. 1919. Acanthocephala from the _ Illinois River, with descriptions of species and a synopsis of the family Neoechi- norhynchidae. Ill. Nat. Hist. Surv. Bul. 13(8) :225-57+7 pls. 1930. Stephen Alfred Forbes as a scientist. Pp. 24-8 in Memorial of the funeral services for Stephen Alfred Forbes, Ph.D., LL.D. University of Illinois Press, [Urbana]. 40 pp. 1947. A history of the Department of Zool- ogy in the University of Illinois. Bios 18(2) :75-97. Vasey, George 1859. Mosses of Illinois. Ill. Ag. Soe. Trans. for 1857-1858, 3:676-9. 1861. Additions to the flora of Illinois. Ill. Nat. Hist. Soc. Trans. 2nd ed. Ser. 1, 1:139-43. Vasey, George, Editor of Botanical Depart- ment 1870a. New plants. 2(9) :288. 1870. Maritime plants of the Great Lakes and the interior. Am. Ent. and Bot. Am. Ent. and _ Bot. 2(11) :342-4. Vestal, Arthur G. 1913. An associational study of Illinois sand prairie. Ill. Lab. Nat. Hist. Bul. 10(1) :1-96+5 pls. Vohs, Paul A., Jr. 1957. A combination salad _ for Ill. Wildlife 13(1) :3-5. Walsh, Benj. D. wildlife. 1861. Insects injurious to vegetation in IIli- nois. Ill. Ag. Soc. Trans. for 1859- 1860, 4:335-72. 1863. List of the Pseudoneuroptera of IIli- LITERATURE CITED 233 nois contained in the cabinet of the writer, with descriptions of over forty new species, and notes on their structural affinities. Acad. Nat. Sci. Phila. Proc. for 1862:361-402. 1864a. Notes by Benj. D. Walsh. Ent. Soc. Phila. Proc. for 1863-1864, 2(3) :182- 22, 18644. On the pupa of the ephemerinous genus Baetisca Walsh. Ent. Soc. Phila. Proc. 3:200-6. [ Walsh, Benj. D.] 1866. The new potato bug. Pract. Ent. 2(2) :13-6. Walsh, Benj. D. 1868a. An address to Southern II]linois Fruit Growers’ Association. II]. Hort. Soc. Trans. for 1867, n.s., 1:143-4. 18684. First annual report of the Acting State Entomologist. Append. to III. Hort. Soc. Trans. for 1867. 103 pp. +2 pis. Walsh, Benj. D., and Charles V. Riley, Editors 1868a. Salutatory. Am. Ent. 1(1) :1-3. 1868b. Hogs vs. bugs. Am. Ent. 1(1) :3-6. 1869. The asparagus beetle. Am. Ent. 1(6) :114—-5. Walters, C. S., B. M. Zuckerman, and W. L. Meek 1955. The effect of oak wilt on the cold- soak treatability of oak fence posts. Jour. Forestry 53(5) :356-8. Wandell, Willet N. 1948. Agricultural and wildlife values of habitat improvement plantings on the Illinois black prairie. N. Am. Wild- life Conf. Trans. 13:256-69. Ward, Henry B. 1930. Stephen Alfred Forbes—a_ tribute. Science, n.s.. 71(1841) :378—-81. Weed, Clarence M. 1890. A descriptive catalogue of the Pha- langiinae of Illinois. Ill. Lab. Nat. Hist. Bul. 3(5) :79-97. 1891. Sixth contribution to a knowledge of the life history of certain little-known Aphididae. II]. Lab. Nat. Hist. Bul. 3(12) :207-14. Weed, Clarence M., and Ned Dearborn 1903. Birds in their relations to man. J. B. Lippincott Co., Philadelphia. viii +380 pp. Weiss, Harry B. 1936. The pioneer century of American entomology. Published by the au- thor, New Brunswick, N. J. 320 pp. Mimeo. Wells, Morris M. 1918. The reactions and_ resistance of fishes to carbon dioxide and carbon monoxide. Ill. Lab. Nat. Hist. Bul. 11(8) :557-71. West, James A. 1910. A study of the food of moles in IIli- nois. Ill. Lab. Nat. Hist. Bul. 9(2): 14-22. 234 Wickliff, E. L. 1933. A summary of fisheries Am. Fish. Soc. Trans. for 63 :257-64. Wiebe, A. H. 1929. The effects of various fertilizers on plankton production. Am. Fish. Soc. Trans. for 1929, 59:94-101. Wilber, C. D., Secretary 1861a. Transactions of the Illinois Natural History Society for the year 1860. III. Ag. Soc. Trans. for 1859-1860, 4:533- 675. Wilber, C. D. 1861b. Mastodon giganteus. Ill. Ag. Soc. Trans. for 1859-1860, 4:587—92. 1861c. Museum of the Illinois State Natural History Society. Ill. Ag. Soc. Trans. for 1859-1860, 4:673-5. Wilber, C. D., Secretary 1861d. Transactions of the Illinois Natural research. 1933, History Society. 2nd ed., Vol. I, Ser. I. Springfield. 194 pp. Wolf, John, and Elihu Hall 1878. A list of the mosses, liverworts and lichens of Illinois. IJ]. Lab. Nat. Hist. Bul. 1(2) :18-35. Wood, Frank Elmer 1910a. A study of the mammals of Cham- paign County, Illinois. Ill. Lab. Nat. Hist. Bul. 8(5) :501-613+3 pls. 19104. On the common shrew-mole, Scalo- pus aquaticus machrinus (Rafi- nesque), in Illinois. Ill. Lab. Nat. Hist. Bul. 9(1) :1-13. Woodworth, Charles W. 1887. Jassidae of Illinois. Part I. Ill. Lab. Nat. Hist. Bul. 3(2) :9-37+3 pls. Yeager, Lee E. 1941a. A contribution toward a bibliogra- phy on North American fur animals. Ill. Nat. Hist. Surv. Biol. Notes 16. 209 pp. Mimeo. 1941b. Wildlife management on coal stripped land. N. Am. Wildlife Conf. Trans. 5:348-53. Coal-stripped land as a mammal habitat, with special reference to fur 1942. I-ttinois NATuRAL History SurvEY BULLETIN Vol. 27, Art. 2 animals. Am. Midland Nat. 27(3): 613-35. 1943. Fur production and management of Illinois drainage system. N. Am. Wildlife Conf. Trans. 8:294-301. 1945. Capacity of Illinois land types to produce furs. N. Am. Wildlife Conf. Trans. 10:79-86. 1949. Effect of permanent flooding in a river-bottom timber area. III. Nat. Hist. Surv. Bul. 25(2) :33-65. Yeager, Lee E., and Harry G. Anderson 1944. Some effects of flooding and water- fowl concentration on mammals of a refuge area in central Illinois. Am. Midland Nat. 31(1) :159-78. Yeager, Lee E., and William H. Elder 1945. Pre- and post-hunting season foods of raccoons on an Illinois goose ref- uge. Jour. Wildlife Mgt. 9(1) : 48-56. Yeager, Lee E., and R. G. Rennels 1943. Fur yield and autumn foods of the raccoon in Illinois River bottom lands. Jour. Wildlife Mgt. 7(1) :45- 60. Yeatter, Ralph E. 1943. The prairie chicken in Illinois. Ill. Nat. Hist. Surv. Bul. 22(4) :377-416. Bird dogs in sport and conservation. Ill. Nat. Hist. Surv. Cire. 42. 64 pp. Effects of different preincubation temperatures on the hatchability of pheasant eggs. Science, ns. 112 (2914) :529-30. Is the prairie chicken doomed? Ill. Wildlife 12(2) :8-9. Yeatter, Ralph E., and David H. Thompson 1952. Tularemia, weather, and rabbit pop- ulations. Ill. Nat. Hist. Surv. Bul. 25 (6) :351—-82. Zuckerman, Bert M., and E. A. Curl 1953. Proof that the fungus pads on oak wilt-killed trees are a growth form of Endoconidiophora fagacearum. Phytopathology 43(5) :287-8. Zuckerman, Bert M., and P. F. Hoffman 1953. C** as a tool for the study of the oak wilt fungus. Phytopathology 43(9): 490. 1948. 1950. 1957. ——— ss Se ee eee ee ee Uy RPh by 2 hats t Cet SPAN Some Recent Publications of the ILtrnois NaturAL History Survey BULLETIN Volume 26, Article 1.—The Mayflies, or Ephem- eroptera, of Illinois. By B. D. Burks. May, 1953. 216 pp., frontis., 395 figs., bibliog. $1.25. Volume 26, Article 2.—Largemouth Bass in Ridge Lake, Coles County, Illinois. By George W. Bennett. November, 1954. 60 pp., frontis., 15 figs., bibliog. Volume 26, Article 3.—Natural Availability of Oak Wilt Inocula. By E. A. Curl. June, 1955. 48 pp., frontis., 22 figs., bibliog. Volume 26, Article 4.—Efficiency and Selec- tivity of Commercial Fishing Devices Used on the Mississippi River. By William C. Starrett and Paul G. Barnickol. July, 1953. 42 pp., frontis., 17 figs., bibliog. Volume 26, Article 5.—Hill Prairies of IIli- nois. By Robert A. Evers. August, 1955. 80 pp., frontis., 28 figs., bibliog. Volume 26, Article 6.—Fusarium Disease of Gladiolus: Its Causal Agent. By Junius L. Forsberg. September, 1955. 57 pp., frontis., 22 figs., bibliog. Volume 27, Article 1.—Ecological Life History of the Warmouth. By R. Weldon Larimore. August, 1957. 84 pp., color frontis., 27 figs., bibliog. CIRCULAR 32.—Pleasure With Plants. By L. R. Tehon. July, 1958. (Fifth printing, with revisions.) 32 pp., frontis., 8 figs. 42.—Bird Dogs in Sport and Conservation. By Ralph E. Yeatter. December, 1948. 64 pp., frontis., 40 figs. 45.—Housing for Wood Ducks. By Frank C. Bellrose. February, 1955. (Second print- ing, with revisions.) 47 pp., illus., bibliog. 46.—Illinois Trees: Their Diseases. By J. Cedric Carter. August, 1955. 99 pp., frontis., 93 figs. Single copies free to IIli- nois residents; 25 cents to others. 47.—Illinois Trees and Shrubs: Their Insect Enemies. By L. L. English. May, 1958. 92 pp., frontis., 59 figs. index. Single copies free to Illinois residents; 25 cents to others. List of available publications mailed on request. Single copies of ILLINoIs NATURAL History Survey publications for which no price is listed will be furnished free of charge to individuals until the supply becomes low, after which — nominal charge may be made. More than one copy of any free publication may be o ia without cost by educational institutions and official organizations within the State of iin prices to others on quantity orders of these publications will be quoted upon request. Address orders and correspondence to the Chief Inurnois Natura History SuRvEY Natural Resources Building, Urbana, Illinois Payment in the form of money order or check made out to State Treasurer of Illinois, Springfield, Illinois, must accompany requests for those publications on which a price is set. i BIOLOGICAL NOTES 29.—An Inventory of the Fishes of Jordana Creek, Vermilion County, Illinois. ris Rig Weldon Larimore, Quentin H. a and Leonard Durham. August, 1952, pp., 25 figs., bibliog. ( 30.—Sport Fishing at take Chautauqua, near ; Havana, Illinois, in 1950 and 1951. By William C. Starrett and Perl L. McNeil, Jr. August, 1952. 31 pp., 22 figs. bibliog. 31—Some Conservation Problems of the i Great Lakes. By Harlow B. Mills. ia ber, 1953. (Second printing.) 14 pp., a bibliog. a 33—A New Technique in Control of the House Fly. By Willis N. Bruce. Decem- ber, 1953. 8 pp., 5 figs. 34.—White-Tailed Deer Populations in Ili. nois. By Lysle R. Pietsch. June, 1954, 24 pp., 17 figs., bibliog. es 35——An Evaluation of the Red Fox. By — Thomas G. Scott. July, 1955. (Second printing.) 16 pp., illus., bibliog. 36—A Spectacular Waterfowl Migratio . Through Central North America, By Frank — C. Bellrose. April, 1957. 24 pp., 9 figs, = 37.—Continuous Mass Rearing of the Euro- pean Corn Borer in the oar By Paul Surany. May, 1957. 12 pp., 7 figs, %: bibliog. 38.—Ectoparasites of the Cottontail Rabbit ing Lee County, Northern Illinois. By Lewis J. © Stannard, Jr., and Lysle R. Pietsch. June, — 1958. 20 pp., 14 figs., bibliog. 39.—A Guide to Aging of Pheasant Embryos. _ By Ronald F. Labisky and James F. oe 4 pp., illus., bibliog. MANUAL 3.—Fieldbook of Native [llinois Shrubs. By Leo R. Tehon. December, 1942. 307 pp., 4 color pls., 72 figs., glossary, index. $1.75 4.—Fieldbook of Illinois Mammals. By Donald — F. Hoffmeister and Carl O. Mohr. June, 1957. 233 pp., color frontis., 119 figs., glos- — sary, bibliog., index. $1.75. : ILLINOIS NATURAL HISTORY SURVEY Bulletin Printed by Authority of Ce the State of Illinois Lead Poisoning as a Mortality Factor in Waterfowl Populations FRANK C. BELLROSE STATE OF ILLINOIS e Wim G. Srratron, Governor DEPARTMENT OF REGISTRATION AND EDUCATION e Vera M. Binks, Directer NATURAL HISTORY SURVEY DIVISION e¢ Hartow B. Muts, Chief MAT IOKS Pers Uae. jbo MeL tINOIS. NATURAL HISTORY SURVEY Bulletin Volume 27, Article 3 aE Printed by Authority of May, 1959 the State of Illinois Lead Poisoning as a Mortality Factor in Waterfowl Populations Poet K- ©. BELLROSE STATE OF ILLINOIS e WILLIAM G. STRATTON, Governor DEPARTMENT OF REGISTRATION AND EDUCATION e Vera M. Binks, Director NATURAL HISTORY SURVEY DIVISION @ Hartow B. Mitts, Chief Urbana Illinois STATEOF TLEINOIs Wittiam G. Srrarron, Governor DEPARTMENT OF REGISTRATION AND EDUCATION Vera M. Binks, Director BOARD OF NATURAL RESOURCES AND CONSERVATION Vera M. Binks, Chairman; Ph.D., D.Sc., Chemistry ; Rosert H. President of the University of Illinois, A. E. Emerson, Ph.D., Biology; Watter H. Newnuouse, Ph.D., Ce Rocer Apams, ANDERSON, ave I., Engineering; W. L. Dretyre W. Morais, Everitt, E.E., Ph.D., Representing the Ph.D.. President of Southern Illinois University NATURAL HISTORY SURVEY DIVISION, Urbana, Illinois SCIENTIFIC AND TECHNICAL STAFF Hartow B. Muixts, Ph.D., Chief Bessie B. East, M.S., Assistant to the Chief Section of Economic bee rs Georce C. Decker, Ph.D., Principal Scientist and Head Jo LH. J BIGGER, IVML.0. Entomologist L. L. Encuisx, Ph_D., Entomologist Wiis N. Bruce, Ph.D., Associate Entomologist Norman Gannon, Ph.D., Associate Entomologist W. H. Lucxkmann, Ph.D., Associate Entomologist Ronatp H. Meyer, M.S., Assistant Entomologist Joun D. Pascuxe, Ph.D., Assistant Entomologist Joun P. Kramer, Ph.D., Assistant Entomologist Rosert Snetsincer, M.S., Field Assistant Carot Morcan, B.S., Laboratory Assistant Eucene M. Bravi, M.S., Research Assistant Ricuarv B. Dysart, B.S., Technical Assistant Recinatp Roserts, A.B., Technical Assistant James W. Sanrorp, B.S., Technical Assistant Eart Stapecpacuer, B.S., Technical Assistant Sue E. Warkins, Technical Assistant H. B. Perry, Ph.D Srevenson Moore, III, Entomology* Zenas B. Noon, Jr., M.S., Research Assistant* Crarence E, Wuire, B.S., Research Assistant* Joun Artuur Lowe, M.S., Research Assistant* fs pela Horrman, B.S., Research Assistant* Cartos A. Wuire, B.S., Research Assistant* Roy E. McLaucuuin, B.S., Research Assistant* Costas Kousxorexas, M.S., Research Assistant* Louise Zincrone, B.S., Research Assistant* Mary E. Mann, R.N., Research Assistant* Ph.D., Extension Specialist in Section of Faunistic Surveys and Insect Identification H. H. Ross, Ph.D., Systematic Entomologist and Head Mitton W. Sanperson, Ph.D., Taxonomist Lewis J. STANNARD, Jr., Ph.D., Associate Taxonomist Puitie W. Smirn, Ph. Di; Associate Taxonomist Leonora K. Guoyp, M.S., Assistant Taxonomist H. B. CunnincHam, MS., Assistant Taxonomist Epwarp L. Mocxkrorp, MS., Technical Assistant Tueima H. Overstreet, Technical Assistant Section of Aquatic Biology Grorce W. Bennett, Ph.D., Aquatic Biologist and Head WiruraM C. seas Ph.D., Aquatic Biologist R. W. Larimore, Ph. Aquatic Biologist Daviv H. Bucx, Ph. oe " Associate Aquatic Biologist Rosert C. Hirtisran, Ph.D., Associate Biochemist Donatp F. Hansen, Ph.D., Assistant Aquatic Biologist Wiruram F. CHILpers, MS., Assistant Aquatic Biologist MariFran Martin, Technical Assistant Joun C. Crarrey, B.S., Field Assistant , Extension Specialist in Entomology* Section of Aquatic Biology—continued Ricnarp E. Bass, Field Assistant Rosert D. Crompton, Field Assistant Arnotp W. Fritz, B.S., Field Assistant* Daviw J. McGinty, Field Assistant* Section of Applied Botany and Plant Pathology J. Cepric Carter, Ph.D., Plant Pathologist and Head J. L. Forssere, Ph.D., Plant Pathologist G. H. Borewe, M.S., Associate Botanist Roperr A. Evers, Ph.D., Associate Botanist Rospert Dan Neeny, Ph.D., Associate Plant Pathologist E. B. Himeuicx, M.S., Assistant Plant Pathologist Wa ter Hartstirn, Ph.D., Assistant Plant Pathologist D. F. Scuoenewetss, Ph.D., Assistant Plant Pathologist Rovenia F. Firz-Geraxp, B.A., Technical Assistant Section of Wildlife Research Tuomas G. Scott, Ph.D., Game Specialist and Head Ratpu £. Yeatrer, Ph.D., Game Specialist Cart O. Monr, Ph.D., Game Specialist F. C. Berirose, B.S., Game Specialist H. C. Hanson, Ph.D., Associate Game Specialist Ricuarp R. Graser, Ph.D., Associate Wildlife Specialist Ronatp F. Lasisxy, M.S., Assistant Wildlife Specialist Frances D. Rossins, B.A., Technical Assistant Vireinta A. Lancpon, Technical Assistant Howarn Crum, Jr., Field Assistant Joun L. Roseserry, B.S., Technical Assistant Rexrorp D. Lorn, D.Sc., Project Leader* Freperick GREELEY, Ph.D., Project Leader* Guien C. Sanpverson, M.A., Project Leader* Jacx A. Exuis, M.S., Assistant Project Leader* Tuomas R. B. Barr, M.V.Sc., M.R.C.V.S., Research Assistant* Bossie Joe Verts, M.S., Field Mammalogist* Erwin W. Pearson, M.S., Field Mammalogist* Keitu P. Daurutin, Assistant Laboratory Attendant* Gary P. Imex, Assistant Laboratory Attendant* Section of Publications and Public Relations James S. Ayars, B.S., Technical ‘Editor and Head Brancue P. Younc, B.A., Assistant Technical Editor Diana R. Braverman, B.A., Assistant Technical Editor Wixruiam E. Crarx, Assistant Technical Photographer MarcGueErite VERLEY, Technical Assistant Technical Library Rutw R. Warrick, B.S., B.S.L.S., Technical Librarian Nett Mires, M.S., B.S.L.S., Assistant Technical Librarian CONSULTANTS: Herretotocy, Hosarr M. Smirn, Ph.D., Professor of Zoology, University of Illinois; Parasito.ocy, Norman D. Levine, Ph.D., Professor of Veterinary Parasitology and of Veterinary Research, University of Illinois; WuDLiFE RESEARCH, WILLARD D. Kuimstra, Ph.D., Wildlife Research, Southern Illinois University. *Employed on_co-operative projects with one of several agencies: United States Army Extension Service, Illinois Department of Conservation, Assistant Professor of Zoology and Director of Co-operative University of Illinois, Illinois Agricultural Surgeon General’s Office, United States Department of Agriculture, United States Fish and Wildlife Service, United States Public Health Service, and others. This paper is a contribution from the Section of Wildlife Research. (86180—5,500—10-58) CONTENTS Sate SMSEV TVET RUE Tee Nan) iG ea ecient eat Soe A Lei laie MDT peewee SAS 236 Perret ONIN ECB So scons c'- pc leeed Wa WNe fe eicgc. sveleinaie 0 agit serene e OM lean eee ale 236 i APM MON AIS Meer t cbt on MIS Rs ters alata Syncdy tgs seiore eas Boece ade ahd care hc calas dR eae TIO 238 aa eS TON IO) =O) SES Nae eras oe Shah MAST Te Pe as alo Mave ce eon © Gudid shown oe Oia Die Bho Agnes a ewe 239 C2 SBVI ae: “LENS GENEL one AE ee ne ee eee Sea aPC eT | 239 Bp irsercstenniee ll yeu tres 5 Se rite ea pica iss nee ecedtan cyehe ste Sua. te Sark aisle he reuinalatetale ree tee 242 MirerLinctacd MPL unacety ete ci. ach cs S. rk Mee a nitoahy o Mba a ice Wrckw a, Plats deals ayk Bl eRe 243 SRLS OTe GaN Gaga ae RN eee cn fear ROE en Se Re a are ee nee er 244 RESUME) Kiso uA. was tps atti. cob relin s< Gah os ig atece woatausln teu dale aid maaan ee ae 245 ee ReatT SMe eo alee 1G) the tne ae Pe Wye oh a ot a aa, v cl SOs ala a-aagbane a dre et ee ewe ine a 246 Mpeeresme ViFEClC OID ie = ONES. Ss oaiiis y civ danse ems Riswe Sue 4 eee vee Worne elites vs Searels E cans 247 Ifcidencexot iuead) Ohnotun Wies OES. io .utce< . dco ade Dae + sod ee asics aver eedaes 247 LTP ATLANTIS Oe | Da ee Se, RON PS 249 PRGESTED WEADeorOr IN). IVIKGRATING DUCKS... 202s 6 os gt aye bee se ee ba ole se tee ome 254 Dhami ivie- tapped OUCKS.... Semis nee bsg as dels or oc Sate a vba} lermeie base Mae 3 eee 254 permeates Lao men nye PMPeN S.-i. a.ciec 0 sacn's Sp cus|s i= ovo 4 Hticie ae alle wien ole oe oleate ie 258 Marvations in ohot Incidence Amonopopecies 2. 2...ok sae ve tae eels oes ele daa sees 259 Real Weriations: dn oot IMiCiIdenCe.); < ciiree isle < clsoo 0 2 cde Buje pide wo sle ee 261 EPEMouicuy aniations: ineolot. Uncidence:..3 «air. e ass ws sos ks wate aa ae cts Rie brie 265 EHEIENCEMOL OVATIONS, ONOE ILEVEIS), Hic, ctasvele cco cges a dlnca oelh pevelam@ ome mapas, sie a 268 Pear VV ILD MALLARDS: WOSED AND) RELEASED: ...2.5¢,6¢ h0 0004 0% ¢¢ 050 h ele cgee osles 269 Pirectsat lmeadvon Varlnerability to Hunting. os06. 20.202 fee cee eee dee owe oe oe 270 Pifecumisiceadcon: Vireration. inate’... $i cr Wei a. 00/0 ott Pate eee 6 Oe aaa 272 Piect of lead on Yeat-of-bandine Mortality Rate: .....2.. 0.020. éesca eect eee 274 RmeR eT rGM ERAT OUSONT Nei iy 2) afcecacers, Ittinois NaturaAL History Survey BULLETIN 240 AIG AYUPTMA Pur YSIS “A “(8561 “& Your “493327) wuUnry youUay ‘UOIssTUIOD UOAIISUOT) LINOSSITAY “St “qay “49x2) syueYs “L, SeeYD LS61 Use "VON BATISUO) jo usw -yuedaq vuelpuy “(SS6l ‘IT Yur pure ¢ *qa,j ‘s19932]) [TEQW “G sowel jaded yuasaid jo s0yINy uolneAsasuoy emo] “(SS61 ‘TZ “G2 *19332[) YPIg “H sourvf pur (Ss6l “eZ “qay “te339]) Joyvodg “gq WIA “T fady “saa32]) yaw “A Preyry susuIEdo qT jal caw aglaes® uls “UOdSIM “(S561 “OT “G2ef “499391 pur ysoday ssaiZoi1g Ajsojseng) "Yd wrsuoasiny) uyef “YT 0} 930U}00j Ul pa}o adUasAJar ‘UT ~pes,{ UOPsO‘y "> puv UOSUBMS AISNE) -AI2 HUP|EMA Pur ysty “Ss “A “(SS61 ‘T Judy Senay) yyy “aq preyory ALIYOHLOAY 70 008 0000S Pare, | = $S61-TS6T “°C yrequid “($561 rt 00091 — | 000'00F*T “paeyeIN, |LS61-SP6T “S1O3ULM 86 000‘T 007 ‘OI pare 6F6T “JIU OT OF 000°F ecobR 2 peueD to LsOn Sl 0 OOL 000‘ 08% PETRI | S961 “G2d—"Uel, gs 617 000‘ 98003 vprurd " €S61 a Oe: Och T eae. PIPPIN, |LS6T-LP6T “SAINT OT 000°T 000001 PAPTLPIA SS6l “49 £0 005. 000‘0ST Preyer CSG. SU $T 000°¢ 000‘0@T ParyP Srol-Lrol “url 6 0 000‘€T | 000‘00F*I PAULIN, |LS61-TH6T “SAUL AN 0°9-0'7 00€-00Z —|000‘0T-000"S Parye OF6I “Url UOISSIUIWO”) ‘ 001 PAUP Peo wel 005 ‘T Paeye Sh61 FO3ULM 009 PArTLETA OF6T “A23UI MA (SS61 € c5-0'S O01 000-007 | YEAS BuIpsiyM | $561 ‘Tdy—ysep| 0 0£-8'¢ SL 00S ‘7-007 PLETE | PS-ES6T “HOTU ofl UEMS BUIPSIYM |PS6I-BF6T “S8utds +071 2s005 vpeurs $561 ‘dy Lz 901 000°S soos wpeurd 6b61 “°C t ayqra B eiie's Clr in ee SE +69 Rielle) ey eke el" ale) Beiehin Prryey 6C61 “190 +007 PALI | OF-6£61 “raauay |) o'r +001 000°OT paeyle 8e6l “°C J aol UBMs SUIS $S61-SF6I +08¢ ‘9s005 vprursy ‘youvyy “uel iso] 4807] INaSdug GHATOANT a swunod. squlgq 10 saulg saulg SaIOddS 40 HWI O LNA) UAd TO UAGWOAN Ao WaAdWON TWdIONITU L ole ie \ PPTL (enous N ae ol | uvMS ‘aSnjay IPT! 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Toole ae Cl UeRa) cee eee es oss KOMBO IVT] nals ahd Big Ae 8 is 2 OS Sl a UuISUOIST Yf ES Gert OO “YSTYysosiqruul AA E> Loa | Hie bie, ee wei suey een So yCT UOTE Ey (ou DJOS2UULPY Fa bigiecs | Idd ISSISSIJAJ aBNjoy OTPLLAA [BUOY JOIYSNUILIIL YAY DULJOAD) YIAON] AVMAT)Y] OLLNVILY NOLLVOO'] eee nnn *peisodas useq aaey Bep a3enbape yoryM s0¥ puB SurUOSsIOd pea] 07 pe}Nq!4}3B UZEq BABY YOTYM ‘7GG6[—QEST ‘SYO-!P [MOJOIEM yuvysodwy—'T] 21481 241 Leap PoIsonNING IN WATERFOWL BELLROSE May, 1959 ' ($561 “LT Avy “19399]) YUH “A preyory b 3qus 0 2}0U}00} Ul pa}d aduasajar ‘(340d -o1 poysyqndun) uva py ‘q preuogd (S561 “7 Jady ‘19349]) YD “Ay preysry JOIIO UT ay} jo qusunivdag ‘Ss “Q ‘(SFé6l ‘gy aunf ‘saj}j07) uvurdeyy “] Iv9sC, Sols YPM Pur ys “Ss “Q ‘40d -21 poaystqndun) adiog “A 251095) UOISSIWIWIOT SHIVG pur ‘uonvisaioy ‘auivg vySLIqIN, “6Y-SI WPaloig ‘sysoday sse1 -Bo1q Ajia}swnd)) uruUpyiyos e510a5) (6b SP6L) J91YOW (S561 T [dy ‘42339]) wa “| paeysry PAIS ATPLLM PUP ysl "S “A “(S561 “LT “42a ‘49332]) youd] *{ uyof Suotssturmoy satia -Ysty] PUL PPTL eULIsINO’T] “(¢S6T ‘OT Avy ‘t93}97) AsouR “YP pseyory IOTAIISG APE PUL YS “SA “(HS6T ‘TL “42g “19942T) suIyIET “MA UYOf (S561 “T Pady “49332]) YUH “y Preyory 0} G |! 0 18 0 fe) \GX0) |! 70 000‘F 00001-0006 +00€ OO! O9T OST—-O0T O1S OOT 000‘7-007 ‘1 +002 ‘01 OOF—-O00E ooe's 000‘ ST 000591 +009 000‘ 00# 000‘0S8 000‘ SZ 000+ 000‘00Z ~000‘0ZT 000‘SZ 0006 SZ 000‘OT 000‘O8E 000‘ 8¢T 000‘0SZ 000‘S9T eo} pasura -usaid “[IvjUld eed peoypes ‘UBMS SUIT} “siya “pre l[e yl dnvos Jassa’] syond syInC] Pree asoo5 MoUs pur onTYg asoa38 MOUS pur ong PIPPI PAPTPEIA asoo5 MOUS puv an{g peaurg PIER [equi paeyle Parle PAPI FS6I-FHEL “STOIUT AN 6¢61 PS61-LP61 “SISIUIM 6F61 “Gey url 961 “990 PHOT “JOIN esol “url CS6I-1S61 ‘[udy -piur 0} yore Py-Ply] Sh61 “YAP FS6I-1S6] “SAOIUTMA PS6I-SHOL ‘SHIM, $561 “4A $561 “qaq—uel SS6I-OS6I “SIOIUT AA $561 “qaq-CS61 “99d FS6l -TS6] “99q-—AON “aBNJayY OPT PTE [BUOHE NY Bag uOIeRS TOOTS CH Avg unsing pur ooslouviyy uvg v1usofi]0) PLO CeCe ONCE OW CeCe tlw ool th oat) asnjay Pug AdoJeISIP, JAAR sJeIg 4v1() AVMATY O1MIOVG -adnjoy UUTPIEMA ean 20yse[nj] *AQuNO, yooqqu’T SOXAT ean (Ajuno+y JurID) aye] SOAIIY SDSUDY ayn] yovag joudey Fees sere tess sets sres-gyery apeg DYSDAGA NJ “ aBNjJayY ATPL [PUOReNY sapuy ea | LS a a eae gr ht Sea aBnjoy AFP [PUOEN axe] PuLs vjoxvq’ Yjnoy AVMAT}Y TWULNA worUL A a SIC eS rR CRMC} U0 THUY | Feces esses sess coyery BfnoyeaIes DUDISINO'T Se tg *HOATISIY joodAry> f tam SDSUDYLE -aSnjay APTI [BUEN ee osuly 242 ILLINoIs NATURAL History SURVEY BULLETIN William R. Miller (letter, May 19, 1955) reported: “I have on a few occa- sions seen what to my mind was a case of death due to lead poisoning.” James A. Lee (letter, March 29, 1955) reported: “As far as I can ascertain, we have never had a waterfowl die-off in New Hamp- shire attributable to lead poisoning.” Charles L. McLaughlin (letter, May 23, 1955) reported: “I have no authentic rec- ords of ducks dying of lead poisoning in Massachusetts, and it is my opinion that this type of mortality is unimportant in the state. A few years ago reports of large scale mortality from lead poisoning in the coastal wintering black ducks was re- ported, but investigation revealed that the mortality was due to starvation rather than lead.”’ Ruth S. Billard (letter, May 3, 1955) reported as follows for the Con- necticut State Board of Fisheries and Game: “We are not aware of any water- fowl succumbing from lead poisoning.” Thomas J. Wright (letter, April 26, 1955) reported: “Rhode Island, to the best of my knowledge, has never had any waterfowl losses that could be attributed to lead poisoning.” From New York, Donald D. Foley (letter, May 3, 1955) wrote: “There are without doubt many instances of such poi- soning in this state, particularly in late winter and early spring, of which we are not aware. However, we feel that the over-all picture is not too serious as to di- rect mortality.” L. G. McNamara (let- ter, April 27, 1955) reported: ‘‘As far as we know, lead poisoning is not a problem in New Jersey.” Robert E. Stewart (let- ter, May 21, 1955) of the U. S. Fish and Wildlife Service, in referring to the Maryland marshes, reported: “On sev- eral occasions, during the pdst years, div- ing ducks which appeared unable to fly were collected and found to contain worn lead pellets.’ In Delaware, Everett B. Chamberlain (letter, April 11, 1955) knew of only two duck deaths which were suspected to be from lead poisoning. In Virginia, C. P. Gilchrist, Jr. (let- ter, June 20, 1955), expressed his belief that some ducks are lost to lead poison- ing, but not in large enough numbers ta be brought to the attention of the Com- mission of Game and Inland Fisheries. Farther south, T. Stuart Critcher (let- Vol. 27, Art. 3 ter, May 13, 1955), reporting from North Carolina, remarked: “To my knowledge we have no records of losses in waterfowl populations as a result of lead poison. Un- doubtedly, such losses do occur from time to time.” Dr. J. H. Jenkins (letter, May 12, 1955) of the University of Georgia wrote: “I don’t know of a sin- gle case of lead poisoning of waterfowl in Georgia. For one thing, there is very lit- tle shooting over established marshes.” E. B. Chamberlain, Jr. (letter, April 22, 1955), reported concerning lead poison- ing: “So far as we have been able to de- termine, there have never been any large scale losses of waterfowl in Florida due to this cause.” Mississippi Flyway.—All but three states in the Mississippi Flyway have re- ported die-offs of waterfowl as a result of poisoning from ingested lead shot, table 1. Among the largest losses have been those reported from Louisiana. The largest die-offs in Louisiana have been at Cata- houla Lake in La Salle Parish, where 20,- 300 ducks are estimated to have died from lead poisoning in the period 1950- 1955. Lead poisoning among the water- fowl of Catahoula Lake probably dates back farther than 1930, for E. R. Kalm- bach in his 1930 report (on file, U. S. Fish and Wildlife Service) mentions a duck malady as occurring in previous years at that lake. The largest known single outbreak of lead poisoning occurred in the Claypool Reservoir area near Weiner, Arkansas, between mid-December of 1953 and mid- February of 1954. John W. Perkins (let- ter, February 12, 1954), game agent for the U. S. Fish and Wildlife Service, esti- mated that during that period 16,000 ducks, most of them mallards, succumbed to lead poisoning. A similar die-off of mallards had pre- viously occurred there in early February of 1951. The die-off was investigated by John J. Lynch (letter, February 9, 1951) of the U. S. Fish and Wildlife Service, who reported seeing over 50 carcasses on less than 3 acres of the 1,300 acre reser- voir. He concluded that the casualties “numbered in the thousands.” Further- more, Lynch stated that a die-off of simi- lar proportions occurred on the same res- ervoir in the winter of 1948—49. May, 1959 In Missouri, the largest reported die- off of ducks from lead poisoning took place at the Squaw Creek National Wild- life Refuge, where 10,000 out of 150,000- 205,000 mallards died during the winter of 1956-57. In the previous winter, 5,000 mallards out of the 200,000 on the ref- uge died from lead poisoning. Other die- offs occurred there every winter at least as far back as 1945; reported mortality varied from 50 to 300 victims per year. Additional die-offs of mallards occurred at Dalton Cut-off in Chariton County in 1949 and at the Swan Lake National Wildlife Refuge in 1939, 1952, 1953, and 1954. Hovey Lake, Posey County, Indiana, has been a trouble spot for many years. As mentioned earlier, Phillips & Lin- coln (1930:165) reported ducks dying there from lead poisoning as far back as 1922. The largest die-off there in recent years, an estimated 1,000 ducks, took place during the winter of 1947-48 (James D. McCall, letter, February 5, 1955). Reported losses since then have been sporadic and rather small, except for the death of 219 Canada geese in 1953 and 120 in 1955-56 (Martin 1957:114). Small die-offs, aggregating 678 birds, are reported to have occurred at Hovey Lake, the Kankakee State Game Preserve area (Starke County), and the Willow Slough State Game Preserve (Newton County) during January and February, 1955. Since 1947, wherever large numbers of mallards have wintered in central Ilinois, there have been some outbreaks of lead poisoning. Most of the reported die-offs have occurred on, or in the vicinity of, the Chautauqua National Wildlife Ref- uge, near Havana, where 13,000 ducks are estimated to have died from lead poi- soning in the period 1941-1957, table 1. The largest single outbreak of lead poison- ing among waterfowl of Illinois occurred there in January and February of 1957, when an estimated 5,000 succumbed. The second largest die-off occurred at Stump Lake, north of Grafton, where 3,000 mal- lards were victims of lead poisoning in January, 1948. In Iowa, sporadic outbreaks of lead poi- soning among ducks have been noted since 1936, according to Everett B. Speaker (letter, February 23, 1955), but only one BELLROSE: LEAD POISONING IN WATERFOWL 243 die-off amounted to over 1,000 birds, ta- ble 1. That one took place at Forney Slough, in Fremont County, during the winter of 1948. Reported losses from lead poisoning among waterfowl in the lake states of Minnesota, Wisconsin, and Michigan have been minor, table 1. In Wisconsin, small losses of whistling swans occurred in the Green Bay area in the springs of 1948-1954. L. R. Jahn (letter, February 16, 1955) reported that, although ducks were victims of lead poisoning in both spring and fall, their losses had been spo- radic. H. J. Miller (letter, February 23, 1955) wrote that Michigan had not known an appreciable die-off of ducks from lead poisoning since the taking of waterfowl records was begun in 1940. In the spring of 1942, 16 whistling swans were found dead from lead poisoning on widely separated marshes of southeastern Michigan. In the winter of 1953-54, 100 whistling swans and 75 mallards were reported as dying from lead poisoning at the Shiawassee National Wildlife Refuge, near Saginaw (Richard E. Griffith, letter, April-1,- 1955). After studying the mortality in large populations of ducks wintering, 1949- 1952, on the Detroit River in Michigan, Hunt & Ewing (1953:362, 367) con- sidered lead poisoning to be of little im- portance as a mortality factor. In Ohio, lead poisoning has evidently been a minor problem, for Delmar Hand- ley (letter, April 28, 1955) stated that only a few ducks and geese had been found afflicted by this disease. A suspected case of lead poisoning in Tennessee waterfowl was reported by Parker Smith (letter, May 5, 1955) as affecting 40 or 50 mal- lards along the Obion River in February, 1954. In three states of the Mississippi Fly- way, Kentucky, Mississippi, and Alabama, lead poisoning losses have not been re- ported (letters: Frank Dibble, April 12, 1955; W. Walter Beshears, Jr., May 9, 1955; and Alec Bumsted, March 1, 1955), but some losses undoubtedly oc- cur in those states. Central Flyway.—Although die-offs of waterfowl from lead poisoning have occurred at several places in the Central Flyway, they have not been so large as 244 those in the Mississippi Flyway, table 1. Largest losses in the Central Flyway have been reported from the Sand Lake Na- tional Wildlife Refuge area of South Da- kota, where more than 10,700 mallards succumbed to lead poisoning over a span of 10 winters. A large die-off of ducks reported in Lubbock County, Texas, during the win- ter of 1944 was a most unusual one. De- tails were reported in a letter (June 18, 1945) from Oscar L. Chapman, then As- sistant Secretary of the Department of the Interior, to the Secretary of War, Henry L. Stimson. Excerpts are as follows: “During the past winter approximately 800 wild ducks were found dead at two small lakes on the grounds of the Lub- bock Army Air Field, Texas. Field studies conducted by the Fish and Wild- life Service of this Department revealed that these losses were due primarily to lead poisoning resulting from ingestion of lead shot which drop into one of these lakes during skeet practices. Studies con- ducted by Army personnel indicated that 80 per cent of the dead ducks examined contained lead pellets in their gizzards. . . . It is estimated that the annual loss from the two lakes is between 5,000-—10,- 000 ducks, many of which perish on their northward migration. This estimate is substantiated by numerous reports of ema- ciated dead and live ducks being found or seen in areas north of Lubbock.” In Nebraska, George V. Schildman (letter, March 5, 1955) reported siz- able die-offs of blue geese (Chen caeru- lescens) and lesser snow geese (Chen hy- perborea) from lead poisoning, table 1. In regard to loss of ducks, he stated: “The numerous rainwater basins in Clay, Fillmore, and York counties provide some losses each spring. . . . The losses are com- monplace, but—to my knowledge— haven’t been conspicuous and _ concen- trated. However, these basins cover an extensive area, and the total loss may be considerable.” According to Richard E. Griffith (let- ter, April 1, 1955): “Minor losses have been reported from the Salt Plains Ref- uge (Oklahoma), usually in single iso- lated cases. An occasional bird with lead poisoning is picked up on other refuges throughout the Southwest, but in most in- I~ttrnors NaturAL History SURVEY BULLETIN Vol. 27, Art. 3 stances it is felt the shot was ingested prior to arrival.’’ Griffith reported some fatalities among mallards at the Fort Peck Game Range in Montana, where 5,000 to 17,000 winter. Elsewhere in Montana, Wynn G. Freeman (letter, April 23, 1955) reported he had found no water- fowl suffering from lead poisoning. Other waterfowl biologists in the Cen- tral Flyway who have yet to find mor- tality in waterfowl from lead poisoning are B. A. Fashingbauer (letter, February 17, 1955), North Dakota; Robert L. Patterson (letter, February 8, 1955), Wy- oming; and Levon Lee (letter, February 19, 1955), New Mexico. Pacific Flyway.—The largest out- breaks of lead poisoning among waterfow] of the Pacific Flyway have been reported from California, table 1. In 1939, ducks estimated at 9,500 died from lead _ poi- soning in the Central Valley, San Fran- cisco Bay, and Suisun Bay areas of Cali- fornia, table 1, but it is not known to what extent die-offs approach this number every year, for the problem was investi- gated in detail in only that year by the California Department of Fish and Game. In the winters beginning in 1944 and end- ing in 1954, 4,000 ducks were estimated to have become victims of lead poisoning at the Salton Sea National Wildlife Ref- uge in southern California. Both the Tule Lake and the Lower Klamath National Wildlife refuges in northern California, according to Rich- ard E. Griffith (letter, ‘May 17, 1955), have sections heavily shot over, and yet reported losses from lead poisoning have been surprisingly low. From Utah, Noland F. Nelson (letter, February 19, 1955) reported regarding lead poisoning: “During the past 10 years of waterfowl management work on Utah’s marshlands, I have observed no large die- offs of waterfowl resulting from lead poi- soning. However, a few lead poisoning losses have been recorded every year. These recorded losses were almost always during the winter and early spring months on some of the areas of heavy shooting around Great Salt Lake... . A few emaciated mallard, pintail, shov- eler, and whistling swan have been exam- ined almost every winter and a large per cent have contained ingested lead shot. May, 1959 The keeper of a local aviary rescued 33 sick whistling swans one winter and 28 died from lead poisoning.” In discussing losses of waterfowl from lead poisoning at the Bear River Migra- tory Bird Refuge, Utah, Richard E. Grif- fith (letter, April 1, 1955) emphasized that the loss cited, table 1, was a mini- mum one and should not be construed as a reliable indicator of total mortality. He reported that outbreaks of lead poisoning occurred when ice restricted the birds to a limited feeding area. The development of this situation was most apparent among the 10,000-12,000 whistling swans win- tering at the refuge, for they began to die from lead poisoning as soon as the feed- ing areas became restricted by ice. Thirteen trumpeter swans affected by lead poisoning were found by Dr. Ian McT. Cowan (Tener 1948:12) in Feb- ruary of 1943 on Vancouver Island, Brit- ish Columbia. However, only a very few ducks have been found ill from lead poi- soning in that province (E. W. Taylor, letter, March 22, 1954). In regard to lead poisoning in Wash- ington, Henry A. Hansen (letter, Febru- ary 26, 1955) wrote: “It has been a rare and isolated case that weak or dead ducks have been found to have lead shot in their gizzards in this state since we organized the waterfowl research project in 1947. In no instance have we found a trouble spot that might require remedial action.” Chester E. Kebbe (letter, April 21, 1955) reported that, although an out- break of lead poisoning had not been no- ticed in Oregon, he believed that research would reveal large numbers of waterfowl dying each year from ingested shot. Rich- ard E. Griffith (letter, May 17, 1955) reported that records at the Malheur Na- tional Wildlife Refuge in southwestern Oregon indicated that there had been no losses from this malady in the previous 7 years. A few waterfowl, mostly diving ducks, were victims of lead poisoning at that refuge in 1942. C. Vic Oglesby (letter, March 31, 1955) reported: ‘There have been no major die-offs nor any approaching even moderate die-offs in Nevada within the past 10 years. A very few birds, primarily shovelers, fall victim to lead poisoning each fall on the Stillwater Wildlife Man- BELLROSE: LEAD POISONING IN WATERFOWL 245 agement Area located near Fallon, Ne- vada. This is our largest public hunting area and bears the bulk of the waterfowl shooters within the state.” In Arizona, no losses of waterfowl from lead poisoning have been reported during the past 10 years, according to Wesley B. Fleming (letter, February 8, 1955). Undoubtedly not all the outbreaks of lead poisoning among waterfowl during the past decade have been reported. How- ever, it is believed that outbreaks dis- cussed in this paper include the most im- portant die-offs from lead poisoning, and that these outbreaks represent a cross sec- tion of such conditions in the United States. Today there are only a few places in this country where 1,000 or more ducks might succumb from lead poisoning and not be noticed. Past experience shows that the public becomes alarmed when large numbers of dead ducks are observed and that it reports such events to conser- vation authorities or the press. Moreover, waterfowl are prone to con- centrate in and around refuges; refuge personnel would be among the first to be- come aware of and report any unusual waterfowl mortality. Since the early 1930’s, there have been numerous federal refuges, manned with technically trained personnel, well distributed throughout the four flyways. In addition to the waterfowl die-offs that attract public attention, there are the scattered day-to-day losses that pass unnoticed. These day-to-day losses are ex- tensive; their magnitude is explored later in this paper on the basis of the incidence of ingested shot in waterfowl populations and the toxicity of various doses of lead shot. Lead poisoning outbreaks have occurred more commonly in the Mississippi Flyway than in all the other flyways combined. In both the Mississippi and Central fly- ways, mallards have been the principal victims in all but a few die-offs. A rough estimation of the annual rate of loss of mallards in outbreaks of lead poisoning in the Mississippi Flyway is 1 per cent. Frequency of Die-Offs Some areas have outbreaks of lead poi- soning in waterfowl rarely, some occa- 246 sionally, and others with rather consistent frequency. For example, in Illinois there has been but one outbreak of lead poison- ing near Henry in 18 years; near Grafton there have been two outbreaks in 12 years; at the Chautauqua National Wildlife Refuge there have been outbreaks in 10 of the last 13 years. The frequency and magnitude of lead poisoning outbreaks in a particular area are influenced largely by the following fac- tors: the size of late fall and winter popu- lations of mallards and other species of ducks with similar feeding habits; the kind and amount of food available; the amount of lead shot present as a result of shooting pressure; the availability of shot, determined by bottom conditions, water levels, and ice cover. One reason that the Chautauqua Na- tional Wildlife Refuge area has been the scene of many outbreaks of lead poisoning in waterfowl is that generally 100,000 to 400,000 mallards winter there, making it usually the area of largest winter concen- tration in Illinois. Another reason is that nearby Quiver Creek, which remains partly open during the coldest weather, at- tracts a large proportion of the wintering population to its shot-laden stream bed. Water levels, food, and a lack of ice cover combined to cause the exceptionally large die-off of 5,000 mallards in the Chautauqua area during the winter of 1956-57. A rise in water resulted in the flooding of millet and smartweed beds adjacent to the refuge shortly after the hunting season closed. This area had been heavily shot over, and mallards congre- gated there for a week before a freeze-up forced them to leave. Most of them moved to Quiver Creek. Two to 3 weeks later, mallards in the Quiver Creek area com- menced dying by the hundreds. Other areas in the Mississippi Flyway where there have been consistently fre- quent outbreaks of lead poisoning include Catahoula Lake, Louisiana, 4 out of 6 years; Claypool Reservoir, Arkansas, 3 out of 8 years; and Squaw Creek Na- tional Wildlife Refuge, Missouri, 8 out of 13 years. Seasons of Die-Offs As shown by data in table 1, most wa- terfowl die-offs from lead poisoning have ILtinois NATURAL History SurvEY BULLETIN Vol. 27, Art. 3 occurred during the late fall and early winter months, after the close of the hunting season. Only a very few die-offs have been noted during the hunting sea- son, even though in the southern zone the season has usually extended to Janu- ary 10 or 15. Two large outbreaks have been reported during the hunting season: One of these occurred at Catahoula Lake, Louisiana, during the last two weeks of November and the first week of Decem- ber in 1950; the other took place in the Claypool Reservoir area of Arkansas be- tween mid-December of 1953 and early February of 1954. Outbreaks of lead poisoning are un- usual during the early fall months. Hunter activity keeps ducks out of heavily gunned areas where shot pellets are most heavily deposited, and, as shown later, a sizable number of the ducks suffering from the effects of lead poisoning are shot by hunters. Outbreaks of lead poisoning seldom have been noted among waterfowl during the spring. Principal losses at this season have been among swans and geese. Whis- tling swans have been recorded as dying during the spring at Green Bay, Wiscon- sin, and on the Shiawassee National Wild- life Refuge, Michigan, table 1. A die-off of Canada geese took place in April, 1954, at Lake Puckaway, Wisconsin. In Nebras- ka, losses of blue geese and snow geese have occurred for a number of years dur- ing March and April. Greater scaups were reported by Van Tyne (1929:103- 4) as dying at Houghton Lake, Michigan, during April, 1928. In the spring of 1921 near Florence, Louisiana, many ducks died from lead poisoning, according to Albert Bonin, quoted in an unpub- lished report by E. R. Kalmbach. There are no records to indicate that in recent years wild waterfowl have died from lead poisoning during the summer months. However, Wetmore (1919:2) stated that during the summers of 1915 and 1916 he handled many ducks af- fected by lead poisoning in the Bear River Delta of Great Salt Lake, Utah. In spite of numerous and intensive investigations on botulism and other waterfowl problems at the Bear River Migratory Bird Refuge, lead poisoning losses have not been re- corded there during the summer since May, 1959 Wetmore (1919) reported on his field work of 1915 and 1916. Species Affected by Die-Offs Individuals of most species of water- fowl have been recorded at one time or another as victims of lead poisoning. In addition to those species listed in table 1, the following species have been reported as victims: trumpeter swan, white-fronted goose (Anser albifrons), gadwall (Anas strepera), baldpate (Mareca americana), blue-winged teal (Anas discors), cinna- mon teal (Anas cyanoptera), shoveler (Spatula clypeata), canvasback, greater scaup, common goldeneye (Bucephala clangula), and ruddy duck (Oxyura ja- maicensis). ‘The largest number of spe- cies reported from any one area was found by Donald D. McLean (unpublished re- port, California Department of Fish and Game) in the San Francisco and Suisun Bay areas of California. He reported 257 pintails, 45 shovelers, 15 baldpates, 13 green-winged teals (dnas carolinensis), 7 mallards, 2 lesser Canada geese, 1 cin- namon teal, and 1| canvasback in a group of waterfowl which had succumbed from lead poisoning. Although individuals of many species have died from lead poisoning, it is evi- dent that the mallard has been the prin- cipal victim in outbreaks of lead poison- ing across the nation, table 1. In the Pa- cific Flyway the pintail has made up the largest number of victims. In the Missis- sippi Flyway, however, where mallards and pintails have frequented the same areas, mallard losses have been propor- tionately greater, table 1. Die-offs of the Canada goose, blue goose, and snow goose have been reported for several places, table 1, but losses in these die-offs have been comparatively small. An investigation of a lead poisoning outbreak at Catahoula Lake, Louisiana, in January of 1953 pointed up important differences in the mortality rates of spe- cies. During the period of the outbreak, the waterfowl population was composed of 30,000 pintails, 25,000 mallards, 5,000 green-winged teals, and small numbers of a few other species. Although pintails outnumbered mallards in the population, 5,500 mallards and 1,000 pintails were estimated to have died from lead poison- BELLROSE: LEAD POISONING IN WATERFOWL 247 ing. In a 3-day period, 243 mallards and only 26 pintails were picked up. Not a single dead or incapacitated green-winged teal was found. From these observations, it was de- duced that the habits of the several species of ducks were such as to account for the different mortality rates. Observations of the feeding ducks plus unpublished food habits studies of ducks at Catahoula Lake by Richard K. Yancey of the Louisiana Wild Life and Fisheries Commission sug- gested that both feeding traits and food preferences were involved. Ducks of all three species, mallard, pintail, and green- winged teal, were feeding extensively in flooded beds of chufa (Cyperus esculen- tus), but mallards were puddling more commonly into the bottom for tubers of this plant than were pintails, which were probably feeding more commonly on the Hoating seeds. Green-winged teals ap- peared to be feeding almost entirely on floating seeds. Apparently, in puddling into the bot- tom mud, mallards came into contact with the lead shot more frequently than did pintails, and pintails more frequently than did green-winged teals. The form of the food they consumed undoubtedly influ- enced mortality among those ducks ingest- ing shot. Jordan & Bellrose (1951:18) reported that ducks that fed on small seeds were less affected by ingested lead than were those that fed on corn. The tubers of chufa and the kernels of corn appear to have similar physical proper- ties and they may be expected to have similar effects. Incidence of Lead Shot in Die-Offs Biologists investigating outbreaks of lead poisoning among waterfowl in the Mississippi Flyway, 1938-1955, exam- ined samples of dead and dying mallards for ingested shot, tables 2 and 3. AlI- though 10.4 per cent of the drakes, table 2, and 13.0 per cent of the hens, table 3, found in the outbreaks carried no shot in their gizzards, most, if not all, of these were lead-poisoned victims. James S. Jordan (unpublished report) found in controlled experiments with captive mal- lards that 21 per cent of those dosed with one to four No. 6 shot pellets had no pel- lets in their gizzards at time of dearh. 248 Ittrnois NaTurRAL History SurveEY BULLETIN Vol. 27, Art. 3 Table 2.—Incidence of various ingested shot levels found among drake mallards picked up level is meant the number of ingested lead shot pellets found in a gizzard.) For each state are O PELLET 1 PELLET 2 PELLETS 3 PELLETS 4 PELLETS § PELLETS Location | Num-| Per |Num-| Per |Num-} Per |Num-} Per |Num-| Per | Num-!} Per ber | Cent | ber | Cent | ber | Cent | ber | Cent | ber | Cent | ber | Cent South Dakota 4 11.8 17, 50.0 8 28 pals 5 14.7 0 0.0 0 0.0 Minnesota...| 17 13.8 36 29.3 yy) 17.9 15 12.2 10 8.1 4 3.3 Missouri.... . 6 14.0 8 18.6 5 11.6 6 14.0 9 20.9 5 11.6 Illinois... .. 37 11.9} 90 | 29.0] 49 Ld8 36 11.6 18 5.8 23 7.4 Arkansas.... 3 4.1 6 8.2 20 27.4 8 11.0 5 6.9 3 4.1 Louisiana... 5 4.6 3 28 15 13.9 16 14.8 20 8.5 15 13.9 Tatali 423-72 Loe ie oY) Pa eel bol AY se 80 60 ae 50 Average. . 10.4 Poy Ow) Tre lia by eo LDA er. 9.0 Wad Table 3.—Incidence of various ingested shot levels found among hen mallards picked up level is meant the number of ingested lead shot pellets found in a gizzard.) For each state OQ PELLET 1 PELLET 2 PELLETS 3 PELLETS 4 PELLeTs 5 PELLETS LocaTION Num-} Per |Num-| Per |Num-} Per |Num-| Per |Num-| Per |Num-| Per ber | Cent | ber | Cent | ber | Cent | ber | Cent | ber | Cent | ber | Cent South Dakota} 0 | 0:0} -12 | 48.0] -7 | 28.0] 3 | 12.0} 3 | 12.07 "O00 jiegng Minnesota. . 11 15.5 30 42.3 13 18.3 7 9.9 3 4.2 3 4.2 Missouri... . 3 11.1 7 25.9 3 11.1 6 Pyles) 5 18.5 1 37 Illinois... .. 32 18.1 57 S2e2 30 17.0 19 10.7 7 40 5 2.8 Arkansas... 6 2252. 7 25.9 2 7.4 3 late 2 7.4 1 Bia Louisiana... 8 5.9 11 8.1 21 15.6 31 23.0 16 11.9 18 13.3 Total.....| 60 Eatin Ot reer 70 seed eeOD, aah 36 ooh 2a Average. . 4166 oak fern eate| [ n° UN Ys Reapege sre (ty ICs en lopment [2 EL a pene TS ee eee 6.1 It is apparent that most, if not all, waterfowl found dead without ingested shot in a lead poisoning outbreak had pre- viously ingested lead, but that the lead had passed from their digestive tracts at such late stages of illness that the birds failed to recover. The low proportion of free-flying, lead-poisoned mallards found without ingested shot, as compared with the proportion of lead-poisoned penned birds without ingested shot, suggests that birds in the wild that succeed in voiding shot are more likely to survive than are penned birds. Considerable variation was evident in the amounts of ingested lead shot in mal- lard drakes found dead or dying in four areas. The lowest number of shot pellets per duck was among those affected by lead poisoning at the Sand Lake National Wildlife Refuge, South Dakota, in De- cember of 1951, fig. 3. The next smallest number of ingested shot pellets per duck was among birds picked up, 1941-1954, in the vicinity of the Chautauqua National Wildlife Refuge, Illinois. “The mallards of the Claypool Reservoir, Arkansas, and the Catahoula Lake, Louisiana, out- breaks had a larger number of ingested shot pellets per duck than did those of the Illinois outbreaks, fig. 3. Differences between the four areas in numbers of pellets per drake are believed to have resulted mainly from the differ- ences in (1) availability of shot and (2) diet. The quantity of shot ingested by ducks of a given species is roughly pro- portional to the availability of shot. Diet has an important influence on the sur- vival of ducks that have ingested lead, ac- cording to Jordan & Bellrose (1951 :18- 21), who reported that the harmful effect of ingested lead was most evident in ducks fed on whole corn and much less raat ee 6H" May, 1959 BELLROSE: LEAD POISONING IN WATERFOWL 249 in a dead or moribund condition in lead poisoning die-offs in six states, 1938-1955. (By shot given the number and per cent of drakes represented at each shot level. Over 10 6 PELLETS 7 PELLETS 8 PELLETS 9 PELLETS 10 PELLETS Tora. PELLETS Num-| Per | Num-| Per |Num-| Per | Num-| Per | Num-| Per |Num-}] Per |Num-| Per ber | Cent | ber | Cent | ber | Cent] ber | Cent | ber | Cent | ber | Cent | ber | Cent 0 0.0 0 0.0 0 0.0 0 0.0 0 0.0 0 0.0 gee “100.0 8 6.5 2 1.6 l 0.8 0 0.0 3 2.4 5 4.1} 123 100.0 I 223 1 23 | QF | D3 0 0.0 0 0.0 | 43 99.9 9 29 5 1.6 7 De3 4 8} 6 1.9 26 8.4 | 310 99.9 6 8.2 2 PEA 4 5 6 8.2 2 27 8 11.0 73 100.0 10 9.3 6 5.6 5 4.6 2 18 4 Say, il 6.5 | 108 100.0 34 16 aks 18 ies Eas A. 15 ek 46 See 691 Goo phone 4.9 28 DG Ie 9 fevanes Did ales exces Gaia | LOORO in a dead or moribund condition in lead poisoning die-offs in six states, 1938-1955. (By shot are given the number and per cent of hens represented at each shot level. 6 PELLETS 7 PELLETS 8 PELLETS 9 PELLETS 10 PELLETS Pb 10 Tora. ELLETS Num-| Per |Num-|} Per |Num-| Per | Num-| Per |Num-} Per |Num-} Per |Num-]} Per ber | Cent] ber | Cent | ber | Cent] ber | Cent | ber | Cent | ber | Cent | ber | Cent 9) 0.0 0) 0.0 0 0.0 0 0.0 0 0.0 0 0.0 25 100.0 2 228 0 0.0 | 1.4 1 1.4 0 0.0 0 0.0 71 100.0 0 0.0 0 0.0 9) 7.4 0 0.0 0 0.0 0 0.0 Di 99.9 5 2.8 1 0.6 2 all 1 0.0 1 0.6 17 ONG mii 99.5 2 7.4 2 7.4 0 0.0 0 0.0 1 Si 1 Srv 2 99.9 10 7.4 8 5.9 D AS 5 Bey 1 0.7 4 320) 035 100.0 19 ee, § 11 1 We 7 ie fe oe 3 soe 22 yoke AO?) Nan ee Ae idl tate DIAN edema fens LS 0.6 4.8 100.0 evident in ducks fed on leafy vegetation and the seeds of tame rice, millet, and smartweed. The high percentage of birds with a small number of pellets per bird among the victims in South Dakota probably was a result of (1) lack of easy availability of shot and (2) accelerated losses induced by cold weather and the high toxicity of lead when associated with the corn diet to which the birds were restricted during the winter. Mallards wintering in Illinois, too, were largely restricted to a corn diet, but they had available to them much more shot. The large numbers of shot pellets per bird found in mallard drakes in Arkansas and Louisiana die-offs indicate the avail- ability of large quantities of shot. The small number of drakes without ingested shot, table 2, suggests an excellent sur- vival of those that had voided shot. Appar- ently, the mallard drakes of Arkansas and Louisiana had a better survival rate than those of South Dakota and Illinois be- cause they had a better diet and milder weather. AVAILABILITY OF LEAD The availability of lead shot to water- fowl utilizing a particular body of water is determined by the following factors: (1) the shooting intensity, or amount of shot deposited on the bottom, (2) the firmness of the bottom material, (3) the size of the shot pellets deposited, (4) the depth of water above the bottom, and (5) ice cover. The amount of lead deposited on lake and marsh bottoms as shot pellets from the guns of waterfowl hunters is tremen- dous. A conservative estimate of the number of shells fired for every duck 250 bagged is five; if every shell were of 12 gauge and contained No. 6 shot, then about 1,400 shot pellets would be depos- ited for every duck bagged. In Illinois, the annual kill at some pub- lic shooting grounds has been as high as six ducks per acre, but for all Illinois duck hunting areas over a period of years the kill has averaged about one and one- half ducks per acre per year. The amount of lead shot deposited in Illinois River valley lakes is calculated to be approxi- mately 2,100 pellets per acre per year. += SAND eas LAKE ILtinois NATURAL History SuRVEY BULLETIN Vol. 27, Art. 3 Because of the scattered distribution of blinds, many acres of waterfowl habitat are untouched by spent shot, while small areas near blinds have an annual deposi- tion of shot many times as great as the calculated average for the larger acreage of which they are a part. Most blinds are located on or adjacent to the best water- fowl feeding grounds. In such situations, waterfowl are more likely to pick up shot in their feeding activities than if the blinds, and therefore the pellets, were more evenly distributed. LAKE, SOUTH DAKOTA CHAUTAUQUA, ILLINOIS CLAYPOOL RESERVOIR, ARKANSAS CATAHOULA, LOUISIANA Sea (LAKE PER CENT OF MALES O | rad 3%. 4 oil ne et =) 9... 10 ee NUMBER OF SHOT PELLETS Fig. 3.—Incidence of various levels of ingested lead shot found in gizzards of drake mallards picked up in a dead or moribund condition in each of four areas in which lead poisoning die-offs occurred, 1941-1954. Data, except those for Illinois, are from table 2. May, 1959 A number of surveys have been made of lake and marsh bottoms in an effort to ascertain the availability of lead shot to waterfowl. Wetmore (1919:9-10), i his pioneering investigation of lead poi- soning, examined mud from two areas at the mouth of the Bear River in Utah. In one area he found no shot pellets within 30 to 70 yards of a blind, but he found pellets at sampled 20-yard intervals from 70 yards to as far as 210 yards from the shooting point. He found most pellets at a distance of 130 yards, where he recov- BELLROSE: LEAD POISONING IN WATERFOWL 251 13 pellets at each sampling point; most of the pellets had penetrated through 10 to 12 inches of a soft upper layer of mud to a lower layer of hardened clay. More recent studies, table 4, show the concentrations of lead pellets in bottom samples, most of them taken without spe- cific orientation to shooting blinds. The bottom material sampled varied in thick- ness from 2 to 10 inches. The greatest concentration of lead shot that has been reported was at Lake Puck- away, Wisconsin, table 4. Hartmeister & ered 1 to 12 in each sieve filled with mud. In the other area, Wetmore found | to Hansen (1949:18-22), after investigat- ing three Wisconsin shooting areas, re- Table 4—Number of lead shot pellets per square foot and per acre found in samples of the bottom soils of various lakes and marshes used extensively by waterfowl in North America. The bottom samples varied from approximately one-half inch to 10 inches in thickness.* | YEAR NumBer OF | NumBer oF | NuMBER STATE AREA AND SovareE Feet|/PELLetTs Per} or PELLETS SEASON IN SAMPLE |SouaRreE Foot] Per Acre California...| Sacramento Valley.. jer) 98S 1820) 60 0.45 19,602 North Bay, San Francisco. . Springs 120 0.78 333977 SWisW BAY ses. ee: Sr 260 0.58 25,265 Welearceo: so 80 0.20 8,712 South Bay, San Francisco. . . 240 0.79 34,412 San Joaquin valor s oa 120 bea 59,677 South Coast. Sy eal. 2 40 0.48 20,908 Minnesota...}| Lakes on Carlos Avery 1939-1940 Refuge. . bie Winter 80 0.41 17,859 Lakes adjacent to Carlos Avery Refuge..........+.. 94 Ons ese Ree ie a). 53 0.55 23,958 Rush@lhak ease ny aue cee cree e 11 0.00 0 Fleronwluakerner cert weetss soe 36 1.47 64,032 ie) RE a 2, a rae ee 249 0.14 6,098 Wisconsin...) Lake Puckaway....-./...... 1949 100 pri 118,048 Glanmitakete sn we ayas. dase Winter 67 1.06 46,174 Horicon Marsh a0. eared 53 0.08 3,485 Manitoba. ..| Portage Creek, Delta Marsh 1950 186 Lead 50,965 Cadham Point, Delta Marsh Summer 195 0.39 16,988 Michigan: ...| Saginaw Bay........2225... e 45 m2, 11,761 Maumee. Bayinn... 2 Maek-. 200 OF 27 11,761 imran)... | Willow Slough. .).': So... 1956 14 0.93 40,511 Spring, Fall 14 1.07 46,609 Illinois... ...} Quiver Lake..... 1950 22 0.00 0 Moscow Bay... Summer 60 0.04 1,742 *Sources of data: California: “‘Lead poisoning of California waterfowl,’ unpublished report by Donald D. McLean, Bureau of Game Conservation, California Division of Fish and Game; Minnesota: unpublished reports by Gustav Swanson and C. Gordon Fredine, in Cooperative Wildlife Investigations, University of Minnesota and Minnesota Divi- sion of Game and Fish, Vol. 1, 1937-1939; Vol. 2, 1939-1940; Wisconsin: Hartmeister & Hansen 1949; Manitoba: “Occurrence of lead shot in a waterfowl breeding marsh, ” by George K. Brakhage, unpublished quarterly report of the Missouri Wildlife Research Unit, July—September, 1950; Michigan: “Waterfowl survey of Saginaw Bay, Lake St. Clair, Detroit River, Lake Erie and the marshes adjacent to these waters,’ by Herbert J. Miller, unpublished final report, P-R Project 13-R, Michigan Department of Conservation, January 1, 1943; Indiana: Martin 1957. 252 Intrnoris NaturAL History SurRVEY BULLETIN ported 2.71 pellets per square foot (equiv- alent to 118,048 pellets per acre) at Lake Puckaway, less than half as many pellets per square foot at Clam Lake, and a “neg- ligible amount of lead shot available to waterfowl” on Horicon Marsh. Lake Puckaway, they reported, has a bottom of sand and gravel covered by a thin layer of vegetable matter 1 to 6 inches in depth. Clam Lake has a similar bottom. The dif- ference between the areas in number of pellets per square foot may reflect differ- ences in hunting pressure. Hartmeister & Hansen (1949:19) con- cluded: “Sampling on Horicon marsh re- vealed a practically negligible amount of lead shot available to waterfowl, in spite of the fact that this area is probably as heavily hunted as any lake or marsh in the state of Wisconsin. Obviously, lead shot are soon made unavailable to water- fowl where deep layers of muck and peat are present.” Bottom samples were taken at the Car- los Avery Refuge in Minnesota 5 years after it had been closed to shooting; yet shot pellets were about as numerous there as in adjacent lakes that were hunted dur- ing the 5-year period (unpublished Min- nesota report cited in table 4 footnote). At Rush Lake, a mud-bottomed water area, no lead shot was found in samples taken 15 years after it had been closed to hunting. The highest concentration of lead shot found in the Minnesota lakes sampled was at Heron Lake, which has a hard clay bottom and had been heavily shot over, table 4. Bottom samples taken at Willow Slough in Indiana by Dale N. Martin (1957:113) revealed about the same con- centration of lead shot pellets on October 17, 1956, as on April 26, 1956, table 4. Apparently, during the 6-month period the shot had not settled deeper into the bottom. The bottom area sampled was composed of one-half to 1.5 inches of silt and plant debris over firm sand. In California waterfowl areas, Donald D. McLean (unpublished report cited in table 4 footnote) took bottom samples at levels of 0-2 inches, 4—6 inches, and 8-10 inches below the surface of the bottom. At these three levels he found 61 per cent of the shot in the top layer, 30 per cent in the middle layer, and 9 per cent in the Vol. 27, Art. 3 lowest layer. There was a noticeable dif- ference between places; areas with hard bottoms had most of the shot pellets at depths of less than 6 inches while areas with soft bottoms had a greater propor- tion of shot deeper in the soil. McLean reported that at the Bolsa Chica Club, in southern California, there was a heavy concentration of shot lying on hardpan under 5.5 inches of soft mud. Both Portage Creek and Cadham Point in the Delta Marsh of Manitoba are tra- ditional shooting sites. Portage Creek re- ceives much heavier shooting pressure than does Cadham Point, and shot pellets were more numerous there, table 4. In view of the soft mud bottoms of both areas, the amount of shot found was sur- prisingly high. George K. Brakhage stated in an unpublished report cited in a table 4 footnote that the highest concen- trations of shot in the Cadham Point area were along those transects nearest the de- coy placement. In Michigan, Herbert J. Miller stated in an unpublished report cited in a table 4 footnote that at Mau- mee Bay shot pellets were twice as nu- merous in areas protected from severe wave action as in the exposed areas. Part of this difference may have resulted from differences in shooting pressure, but Miller believed that the wave action and cur- rents were largely responsible in that they covered much of the lead with sediment. Bottom samples taken during the sum- mer of 1950 from two heavily shot-over lakes in the Illinois River valley showed few lead shot pellets, table 4; samples were taken from the top 2 inches of the bottoms of these lakes. Undoubtedly only a small amount of lead shot was found because the expended shot sank in the soft mud and during spring floods was covered by a layer of silt. A study on the silting of Lake Chautauqua (Stall & Mel- sted 1951:10), an Illinois River valley lake, showed an average annual silt accu- mulation of 110 acre-feet in a basin of 3,562 acres. In water areas with silt or peat bot- toms, there is, apparently, only a slight carry-over of lead shot (within the soil depths at which most ducks search for food) from one season to the next. Lead shot is, therefore, most readily available to waterfowl in the fall and winter, dur- eS Se a May, 1959 ing and immediately following the hunt- ing season. High water levels during the spring over much of the fall waterfowl habitat, which includes most shooting grounds, greatly diminish the availabil- ity of lead shot. Most breeding grounds are lightly hunted; therefore, waterfowl are only slightly exposed to lead shot dur- ing the breeding season. As part of a study on lead shot in mud- bottomed lakes, an experiment was con- ducted by the writer at Quiver Lake, in BELLROSE: LEAD POISONING IN WATERFOWL 253 The data in table 5 show that the smaller the shot size, the smaller the amount of recovered lead. Evidently wave action dislodged quantities of shot pel- lets, especially 71/%’s, and scattered them outside the pipes. From the distribution of the remaining pellets, there was, with the exception of 714’s on the moderately firm bottom, evidence that the larger the size, the more prone the pellets were to sink in the bottom soil. In the soft bot- tom soil, most of the shot had settled to Table 5.—Data indicating the penetration of lead shot pellets into bottom soil of two different types at Quiver Lake, near Havana, Illinois. Figures show for each of five pipes, 8 inches in diameter, placed with upper mouth flush with lake bottom, the number of grams of shot pellets recovered at various soil depths, September 3, 1953, and the percentage of the recovered shot that was recovered at each depth. At the upper mouth of each pipe, 150 grams of shot pellets, No. 744 or No. 6, had been deposited on August 13, 1952. Sorr Borrom MoperaTELY Firm Bottom No. 714 Shot No. 6 Shot No. 71% Shot No. 6 Shot No. 4 Shot DEPTH OF ao) se] ae] ae] a] a] se] se] a] oy Sor ee eel ee oe ee eee | tales nv v Y a or) ‘ D 5106 | 2s | Os: 8e | Og.) es | OR} Es Loe Eo 50 Eo 5 oO Eo 50 Eo 50 Eo 50 Om Ay mS Om awa 4 Om Oy eS Ox [aWf24 Om w= 4 O-tinen,..-...-|' 26.0 | 35.6) 20.0 ohare bart Soe sls 7(UaTi TOES eT LeO 56.5 1-2 inches. ..... 40.8 So) oH el0) || 7@ell NB}. 265 oer 19.7 | 46.0 36.6 2=S'inches...... 4.0 505 4.5 4.2 8.4 14.8 U9) 2.4 5.8 4.6 3-“4inches...... Los 2.0 0.9 0.9 re 2.6 1.0 Ie Dal Ve, 4-5 inches...... 0.7 1.0 ORO eens es: 0.5 0.9 OFO) ees eee 0.7 0.6 Potal.....-..| 73.0. | 100.0 | 106.4| 100.0:| 56.9 | 100.0 | 92.0 | 100.0 | 125.6 | 100.0 the Illinois River valley, near Havana. Two areas of the lake bed were selected: one soft, the other moderately firm. In each area, three ceramic pipes, each 8 inches in diameter, were sunk into the soil of the lake bottom during August of 1952, a period in which the water was only a few inches deep; the upper mouth of each pipe was flush with the top layer of soil of the lake bottom. On the soil in the upper mouth of each pipe, 150 grams of shot pellets were deposited: in each of the two areas were one pipe with No. 4 shot, one with No. 6 shot, and one with No. 7\% shot. Slightly over a year later, September 3, 1953, five l-inch layers of soil were re- moved from each of five pipes and screened for lead shot. The sixth pipe, the one in soft mud that contained 4’s, had been dis- lodged and could not be used further in the experiment. the 1—2-inch layer, but, in the moderately firm bottom soil, the bulk of the shot was in the top 1-inch layer. However, in both bottom types, some shot had settled to the 4—5-inch layer. Ground and aerial observations of dab- bling ducks feeding in Illinois marshes in- dicate that most of these ducks feed on or in the top inch of the bottom material. Shovelers and green-winged teals have been watched for many hours wading through shallow water and skimming the surface of the bottom. From the air, their “mud trails” in otherwise clear water give further evidence of their characteristic feeding activities. Blue-winged teals may feed in a manner similar to that common- ly observed for green-wings, but they appear to do more tipping-up to puddle deeper into the bottom mud. Pintails do considerable skimming of the bottom in water only a few inches 254 deep, but, in deeper water, they are prone to puddle out pockets several inches in depth. Mallards, in Illinois at least, dig deeper pockets than do pintails, but these are seldom more than 6 inches in depth. According to Wetmore (1919:3), mal- lards and pintails dig away mud to a depth of 6 to 18 inches and over an area | to 15 feet in diameter as they search for food. Such extensive digging on the part of ducks has been observed by the present writer only around trap sites where large numbers of birds have sifted through bot- tom soil day after day for bait. Under such circumstances, mallards have created holes as large as 2 feet in depth, 25 feet in length, and 10 feet in width. Field observations and food habits stud- ies indicate that, where underwater leafy aquatics occur, baldpates and gadwalls feed almost entirely upon these plants, seldom, if ever, sifting through bottom soils for food. Not only does the depth at which lead shot occurs in bottom soils determine its availability to different species of ducks; the depth of water above the bottom is also a factor. Species of ducks differ to some extent in preferred feeding depths. Dabbling ducks usually utilize waters less than 15 inches in depth, and diving ducks feed at depths of many feet. Among the diving ducks, redheads (Aythya ameri- cana) and ring-necked ducks (Aythya collaris) are prone to feed in shallower water than are lesser scaups and golden- eyes. W hen, in late fall or winter, ice fails to cover waterfowl feeding grounds that have been heavily shot over, the stage may be set for a large die-off of ducks. Ice almost invariably forms first on the shoal water of ponds, marshes, and lake mar- gins such as are commonly used by ducks for feeding and hunters for shooting. The sealing of these waters by ice makes the large quantities nf shot on such areas un- available to waterfowl. At the same time it may cause the ducks to congregate in spring holes and spring-fed streams not covered by ice. If such areas have been heavily hunted, they are potential sources of large die-offs caused by lead poisoning. The extent to which the various spe- cies of waterfowl are exposed to shot pel- lets on the bottoms of marshes and lakes ILtinois NATURAL History SuRVEY BULLETIN Vol. 27, Art. 3 is influenced by the feeding habits of the birds and by the kinds of foods available, as well as by the numbers of shot pellets available. INGESTED LEAD SHOT IN MIGRATING DUCKS The incidence of ingested lead shot in migrating waterfowl populations (the percentages of ducks that carried ingested lead at the time gizzards were collected) was determined by (1) fluoroscopic ex- amination of live-trapped ducks, (2) com- pilation of data obtained from other in- vestigators who had examined waterfow] gizzards for food content, and (3) fluoro- scopic and direct examination (Bellrose 1951:126-7) of gizzards numbering many thousands that co-operating biologists had collected, especially for this study, from ducks in hunters’ bags. Most of the data were from ducks migrating southward in fall and early winter. Shot in Live-Trapped Ducks During the fall months of 1948, 1949, 1950, and 1953, 5,148 mallards were live- trapped and fluoroscoped at the Chautau- qua National Wildlife Refuge, near Ha- vana, Illinois, fig. 4. Ingested lead shot was found in the gizzards of 10.14 per cent of these birds, but more than two- thirds of the gizzards with shot contained only one pellet each, table 6. Because the refuge has been closed to hunting since 1944, it is doubtful if much, or any, of the lead was picked up at the trapping site. Almost twice as many juvenile as adult male mallards carried ingested shot, table 6. The data indicate that more hens than drakes carried ingested shot, but the sam- ple on which the data are based is believed biased by an unduly large proportion of hens fluoroscoped late in the season, when the incidence of birds carrying shot was at its highest. Pintails, blue-winged teals, and wood ducks (Aix sponsa) were caught in baited traps during September at Moscow Bay, 10 miles south of Havana. Examination of these birds by fluoroscopy revealed an incidence of ingested lead that was un- usually high for these species, table 7. The high incidence may have occurred be- cause the traps were on a heavily shot- May, 1959 over area, which, combined with intensive feeding by the ducks, resulted in exposure of the birds to unusually large quantities of lead. At the trapping site, lead shot was avail- able equally to the three species, and, in September, it was unlikely that the birds were obtaining shot elsewhere. Yet, among the species, there were differences in incidence of ingested shot, table 7. Pro- portionally more pintails than wood ducks and proportionally more woodies_ than blue-winged teals carried ingested shot. Apparently, there is a relationship between the weight of a duck and its intake of food and lead. Perhaps under similar condi- tions of food and feeding, the duck spe- cies with the largest individuals have the highest percentages of individuals with in- gested lead shot, table 7. Fig. 4. Illinois Natural History Survey to determine the incidence of ingested lead shot in wild water- fowl trapped alive as well as in dead and moribund birds picked up in the field. Each bird was placed in the cone, which was rotated in front of the fluoroscopic screen. This procedure presented to view more than one plane of the bird’s body and thereby resulted in more precise location of pellets than was possible in a single plane view. Peoria, Illinois.) BELLROSE: LEAD POISONING IN WATERFOWL 25 Cn In two of the three species, table 7, an appreciably greater percentage of juveniles than of adults carried ingested lead shot; in the pintail there was little difference in shot incidence between age groups. In the pintail, blue-winged teal, and wood duck, there were only slight differences between the sexes with respect to inci- dence of shot, but, in the lesser scaup, pro- portionally twice as many drakes as hens carried ingested shot, table 7. The lesser scaups represented in table 7 were trapped on another area near Havana in April, 1953. The seasonal incidence of ingested lead shot among mallards trapped at the Chau- tauqua National Wildlife Refuge during the fall months of 1949 and 1950 is shown in table 8. Most of the mallard groups fluoroscoped early in the season had a An X-ray head and fluoroscopic screen used at the Havana laboratory of the (Photograph from the Journal-Star, fae] Pe - =< ~ N 3 ° > Ittinors NATURAL History SurvEY BULLETIN 256 ol ae ae ae Pea ee Whee ai ea tes nega Nc ae. ys one dy 25 a Gales ae 76 6£T 56 60% 8°11 OFE 89 80€ saquiaidag C1) ieee leaps YONP Poor L9 OO 'T 18 058 OL LLO‘T ss €L@ Jaquisidag | 1S61-6F6I |’ [¥93 pesurm-onig Ser Ls a 96 S11 L8 rq 99 yaquis3dag OSB) eer" an ae pray yay, | pouuexg | peop yay | pourmexg | peop yy | poumexg | prop yy | poumumexg ua) 49d JOquin Ay 3u97) tod JOquUIn Ay jUu97) 13d JOGuUIny jus) 13d JOquIn Ay HLNOJ Uva SaI0ddS SNAH saavuqd Sa TINIAN [ SLTNGY "€S6I-6F6I ‘SPW SNOIsBA je ‘s1ouT]]] ‘euBABT] Je9U padoososony pue paddes saroads snoy yo syonp Suowe joys pea] pa3sosur yo soUaprlou;—y/ 2/qe 00°91 8F cco I cel t ce'0 I L9°0 t 00’ (All €£°6 87 00g os ssape [fe ‘apeurag 816 tlt L10 8 Z1'0 9 Sb 0 7 zs 0 St oF IZ SOL THE 8b8‘b «| sae qe “opel tr $1 $7 970 t ze 0 iS 96'0 SI £80 CI $07 ze 10°01 | 9ST ASS Ta citer aiuaant “oe yay LS'L 6F7 Z10 t £00 I IZ 0 l 9¢°0 ct 611 6c $9°¢ 981 O67°E = ape pePy 3ua7) 4oq quay | ~ 3q ~ quay 12q quay 13aq quay 19q quay 1oq quay 49q 13g -WwnNy 13g -WINAy 13g -WIN NT 1d -UINNY 13d -WINNY Pep -WInN] PEP I -WONy aadoos ssv1) eet aa | aaa ee a ES ol] EL eS ee ee ae ea naa OOO a9Y ANV Xd LOHS HLIAA SLAITAg ¢ uaIGWaAN swonc] 1V.LO J, AIAO SLATITIA q ¢ SLATTA - SLATTAg ¢ SLATTAq 6) LATTSd I *[9A9] JOYS ove je pojuasosdes syONp padoososong jo ju90 Jad pue Jaquinu ay} UaAIS a1B SsB[D age puB XS YORE JO4 (‘psezzis B Ul puNoy sja]jed joys pea, paysefur yo soquinu ay} juve st [aA] JOYS AG) “ESET PUB OS6I-RFGI ‘SYIUOM [[eF 9y3 Fursnp ‘srouryy ‘euBABFY Jvou OFNJOY BPI [BUOVeNY enbnezney’) 943 38 padoososony pue poddes} spseijewW Fuowe puNo;Z sjaaa] JOYS pajsasur snolswBA JO aoUapIou[—~ 9 a/qBL Se SS SO ee - —_— ~~ a May, 1959 lower percentage of individuals with in- gested shot than had groups fluoroscoped later in the season. The decline in the in- cidence of ingested shot among _ birds fluoroscoped in the December 20-24 pe- riod may have occurred as a result of the freeze-up of the lakes a week or two be- fore, or as a result of a rapid die-off of lead-poisoned birds in a period of cold weather. Erratic changes in incidence of ingested shot from period to period were evidence of population changes brought about by the arrival and departure of migrating mallards that varied greatly from flight to flight in the amounts of ingested lead they carried. A few waterfowl in Illinois have been fluoroscoped in late winter or spring for evidence of ingested lead shot. Ingested shot was found in a moderate percentage of the lesser scaups examined, table 7. It was found in a very small percentage of the birds in one group of pintails; it was not found in another group of pintails nor in a sample of Canada geese, table 9. Many ducks in other states have been fluoroscoped for evidence of ingested lead shot, table 10. In Michigan, small per- centages of mallards and black ducks (Anas rubripes) were found to carry in- gested lead during the winter and spring months. Lesser scaups that were fluoro- scoped during the spring months contained BELLROSE: LEAD POISONING IN WATERFOWL 257 no ingested shot. Examination of winter- ing ducks (most of them black ducks, can- vasbacks, lesser scaups, and redheads) by Hunt & Ewing (1953:362) along the De- troit River disclosed that less than 4 per cent of 7,700 ducks fluoroscoped had lead in their gizzards. Of more than 1,000 ducks, most of them black ducks, that were fluoroscoped during the fall, winter, and spring months in New York, only a very small propor- tion carried ingested lead, table 10. Only a small proportion of mallards trapped during the winter months in South Da- kota had lead in their gizzards. Of six species of ducks fluoroscoped during the summer months in the Great Salt Lake Basin of Utah, the mallard was the only species in which a moderately large proportion of individuals carried in- gested lead, table 10. An astoundingly large proportion of the mallards, pintails, and redheads, and a smaller proportion of the blue-winged teals fluoroscoped during the summer at Delta Marsh, Manitoba, carried ingested lead shot, table 10. All of the redheads and most of the blue-winged teals and pin- tails were juveniles. The findings of Elder (1950:501) agree with Illinois data in indicating that juvenile ducks are more likely to ingest lead shot than are adults; at Delta, over twice as large a percentage of juveniles as of adult mal- Table 8.—Periodic incidence of ingested lead shot among mallards trapped at the Chautauqua National Wildlife Refuge near Havana, Illinois, during the fall months of 1949 and 1950. NuMBER OF Ducks NuMBER OF Ducks Per Cent or Ducks P FLUOROSCOPED WirH SHor WirH SHor ERIOD 1949 1950 1949 1950 1949 1950 Average Och 26-30) 2s 129 2 1 4.65 50.00 5.34 Oct. 31—Nov. 4... 224 153 6 SEs) 3.92 eh! Nove 5=9..055.¢- 161 408 14 19 8.70 4.66 5.80 Nov. 10-14....... 194 435 12 32 6.19 7.36 7.00 Novel 5=19 3 a. 361 382 22 44 6.09 BEE52 8.88 Nov. 20-24....... 385 333 30 33 7.79 9.91 Sed/, INows25—29... oe 352 194 40 22 11.36 11.34 11.36 Nov. 30-Dec. 4... 150 69 11 20 TESS 28.99 15.07 Weer 5-905 se 274 24 30 bi 10.95 45.83 13.76 Dec. 10-14....... 54 3 i PEt 33.33 12.28 Wee, W5=19.. 2... I) 12, D Deon 16.67 23.53 Dec. 20-24....... 64 54 6 10.94 TU 11.02 Total. ...|, 2,370 2,069 192 190 AV ELAR One eer nce 8.10 9.18 8.60 258 Ittrnois NATURAL History SuRVEY BULLETIN lards were found with lead in their giz- zards, and over three times as large a per- centage of juvenile as of adult pintails carried ingested lead. On other breeding ground areas— Whitewater Lake, Manitoba, and Eye- brow Lake, Saskatchewan—Elder (1950: 501) examined 3,300 ducks during the summer months of 1948 and 1949 and found that less than 1 per cent of the in- dividuals of any species carried ingested lead. Undoubtedly, most breeding ground areas would show a low incidence of in- Vol. 27, Art. 3 gested shot among waterfowl. The Delta Marsh, which is one of the most heavily shot-over areas in Canada, is an excep- tion. Shot in Ducks Bagged by Hunters With the help of wildlife biologists in almost every state of the Union and some Canadian provinces, the Illinois Natural History Survey obtained data on the in- gested lead shot found in the gizzards of more than 40,000 waterfowl bagged by hunters in the autumn and early winter Table 9—Incidence of ingested lead among pintails and Canada geese trapped and fluoro- scoped in Union County and pintails trapped and fluoroscoped in Henderson County, Illinois, 1952 and 1953. i —————————————— —_ SPECIES PLACE YEAR MontTH Ee Wotan Pintail..............] Henderson County 1952 April? ih 42 0.24 Pintail..............]| Union County 1953 February 95 0.00 Canada goose....... | Union County 1953 February 61 0.00 Table 10.—Incidence of ingested lead shot among waterfowl fluoroscoped in several areas and at different seasons during the period 1941-1954. NuMBER Per Cent AREA SPECIES YEAR Season | Fiuoro- |WitH INGESTED SCOPED SHOT Michigan*.........| Mallard and black ducks )2ts bak oe nts AGAL, 1942 Winter 682 152 Mallard and black duck +. ec ne a OAL 1942 Spring 182 0.4 Lesser scaup.......-- | 1941, 1942 Spring 105 0.0 New Yorkt......-.| Black duck. 1949-1953 Fall, 1,063 0.1 Winter, Spring Other species..... ... My oe aaa 144 0.0 South Dakotat....| Mallard. ... 1950-1954 Winter 3,455 31 WWigalieen. a: siren: Mallard... 25... 1950, 1951 Summer 122 5.7 Gadwall.... 1950, 1951 Summer 16 0.0 Baldpate...:.-/.- 1950, 1951 Summer 98 0.0 ANEAN sect bs ee 2 1950, 1951 Summer 2,199 0.6 Green-winged teal. . 1950, 1951 Summer 213 0.0 Shovelenicci es aac: 1950, 1951 Summer 77 1.3 Manitobatihs.-) saul Mallard nc 2.) 1948, 1949 Summer 537 18.4 | 2th ate (ees ahem ea 1948, 1949 Summer 391 15.6 Blue-winged teal... 1948, 1949 Summer 549 4.9 Redhead......-.... 1948. 1949 Summer 52. 48.1 *From ‘‘Waterfowl survey of Saginaw Bay, Lake St. Clair, Detroit River, Lake Erie and the marshes adjacent P-R Project 13-R, Michigan Department of to these waters,” by Herbert J. Miller. Conservation, January 1, 1943. +From letter of February 18, 1954, by Donald D. Foley, New York Conservation Department. +From letter of March 7, 1955, by Ray Murdy, South Dakota Department of Game, Fish and Parks. ** Summarized from Heuer 1952 +7Summarized from Elder 1950:501. Unpublished final report, , “ 4 } f ’ May, 1959 BELLROSE: LEAD POISONING IN WATERFOWL 299 Fig. 5.—Shot pellets from the gizzards of wild ducks bagged by hunters. Pellets 4 and B were from the same gizzard. Pellet 4 entered the gizzard lumen from the charge that killed the bird. Pellet B had been ingested previously. Pellet 4 exhibits craters caused by the strik- ing of this pellet against others in passage through the shotgun barrel. Pellet B has been some- what smoothed by abrasion in the gizzard; under magnification, the surface of this pellet shows pitting and flaking. Pellet C, another ingested pellet from another gizzard, shows surface erosion resulting from the action of digestive juices in the gizzard. months of the period 1938-1953. Lead pellets, two ingested and one not ingested, are shown somewhat magnified in fig. 5. The number of shot pellets and the spe- cies of ducks represented were known for each of 36,145 gizzards; data from these gizzards were used in an analysis of the incidence of shot among each of the prin- cipal kinds of waterfowl of North Amer- ica, table 11. Variations in Shot Incidence Among Species.—The incidence of ingested lead shot was about seven times as great among ducks as among geese, ta- ble 11. Less than 1 per cent of the (an- ada geese and less than 3 per cent of the blues and snows were found to have lead in their gizzards; the numbers of shot pel- lets per gizzard were exceedingly low. There was a wide range in incidence of ingested shot among the different kinds of ducks, table 11. Kinds in which less than 2 per cent of the gizzards contained lead were bufflehead (Bucephala albeola), green-winged teal, mergansers (Mergus spp.), wood duck, shoveler, and gadwall. Kinds in which lead was found in more than 2 and less than 5 per cent of the giz- zards were blue-winged teal, baldpate, and common goldeneye; in more than 5 and less than 10 per cent, ruddy duck, mallard, black duck, and pintail; in more than 10 per cent, canvasback, lesser scaup, redhead, and ring-necked duck. It is apparent that, with the exception of the last-named group, all of which be- long to the genus Aythya, there is no re- lationship between the incidence of shot and the phylogeny of the birds. Shillinger & Cottam (1937:402) be- lieved that ingestion of lead shot was re- lated to the availability, or lack of availa- bility, of grit, for they stated : ““While lead poisoning is widely distributed throughout all sections of this country, evidence seems to indicate that it is more severe in those sections where there is a deficiency of available gravel that may serve as grit in the gizzard of the birds.” Tener (1948:38) believed grit prefer- ences to be a factor influencing shot inges- tion by waterfowl. He noted that only fine sand appeared in baldpate and green- winged teal gizzards, and that a large proportion of the gizzards of these species contained no shot. He speculated that lead pellets were too large to be selected as grit by these species. If waterfowl were prone to pick up lead shot for grit, then it would seem reason- able to expect many species which pick up large-sized grit particles to have ingested more shot pellets than the numbers re- corded for them in table 11. Ducks that commonly pick up grit particles that are larger than a No. 6 shot and that show a low incidence of shot are wood duck, buf- flehead, and common goldeneye. The giz- zards of geese contain quantities of large grit particles, but the incidence of shot among geese is lower than among ducks, table 11. 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COS 610] € 00:0] 0 000] 0 00:0 | O 900} T St 0] *F 99°7 | UF FIGS BGS ee eS eh rat. |-t¢ 600 | TI 00'°0 | O 600} T 600] TI 81.02% SO lee €7 1 | FI LL oa ee ee Se O68) (ee. b.0S-04 TRIO} Ee 0 od a lt0| 9 GO SE Ce ee ee Sl 900°C: Wie Pe eee eee eas 6L°9 | 6SI‘I| 86:0] #9 | SOO] 6 Bl Oe) FG. | SROrl IS, LOL OR lh PP Ia Rater ease 990° Fe ee Se sxHonqd quay Jaq quay Jaq aie) 49q quay 41oq quay) Joq Ble) 419q Us, qJoq quay Joq dod -WINAY 49d “WONT dod “won 419d -WNnN] 419d “WINNT 12d “WON 419d “WINNT Iq -WNNY Gan INVX"] — a | | ae SAUVZZIL) SaTOddS AVLO SLATIA 9 “i TO UAAGNON fq IAC SLa Taq 9 SLATTAg g SLATTAd P SLATTA ¢ SLATTIS GC LATTA dg if (‘psezzig & UI pUNOJ sjzo]]ed JOYS poJsoFur Jo Joquinu 9Y} JUBUT SI J9Aa] JOYS Aq) “J@A@] JOYS Yous ye pazuasasdas SyONp JO UG0 Jad ay} puv saquinu 9y} UEAIF oIB Sa1oads YOR JO “ESGI-QEG ‘BOOWW YON] JO suoNoss AuBUT UF sJa}UNY WOIJ syJUOUT JozUIM AjIBO pue [|8} #ursnp poureygo spsezzi$ wos poulwsajap se ‘soIdeds JMOJJO}EM JULJIOPUWI FUOW S[IAI] JOYS Pajsasur snorsBA JO BdUaPIOU]—TT I/qeL May, 1959 Evidence that the size of grit usually ingested by individuals of a species of water bird is not related to the ingestion of shot by individuals of that species is ap- parent from a study of the stomach con- tents of 792 coots (Fulica americana). Lead shot was found by Jones (1940:11) in only 12, or 1.5 per cent, of 792 stom- achs. Gravel was found in all but 7 of the 792 stomachs and averaged 33 per cent of the gross contents. The low incidence of shot in the stomachs was attributed by Jones to the habit that the coots have of dabbling for food on the surface of the water as well as to their inability to sift through bottom material with their chicken-like bills. Yet it is reasonable to assume that they could pick up shot pel- lets with their bills as readily as they could pick up grit particles. Food preferences and feeding habits of the various species of waterfowl appear to be largely responsible for the differ- ences in the incidence of ingested shot among the species. The following discus- sion of feeding habits tends to support this thesis. Figures in parentheses fol- lowing the name of a kind of waterfowl indicate the percentage of gizzards in which shot pellets were found, as pre- sented in table 11. Shovelers (1.60) and _ green-winged teals (1.36) feed on the surfaces of mud flats and marsh bottoms. Gadwalls (1.84) and baldpates (3.17) feed upon the veg- etative parts of aquatic plants and seldom have occasion to dig into the bottom soil where shot pellets are present. Wood ducks (1.58) feed so extensively on fruits of woodland plants (Martin, Zim, & Nelson 1951:65) that they sel- dom puddle or sift through lake and marsh bottoms for food. Mergansers (1.46) feed principally on fish and there- fore have less occasion to ingest shot than have species which search through bottom materials for food. Common goldeneyes (3.52) and buf- fleheads (0.69) are prone to frequent large, open bodies of water, over which there is little shooting, and more than 70 per cent of their food is made up of ani- mal life, especially crustaceans and insect larvae (Cottam 1939:132). These ani- mal organisms are found at or near the surface of the bottom; ducks feeding upon BELLROSE: LEAD POISONING IN WATERFOWL 261 them need not sift bottom material, as do those feeding upon the tubers, rootstocks, and seeds of aquatic plants. Mallards (6.79) and pintails (8.87) do considerable feeding in grainfields, which may somewhat reduce their expo- sure to deposited lead shot. However, when feeding in lakes and marshes, they are, for the most part, active in heavily shot-over areas. Moreover, their habit of puddling deep into the bottom soil for seeds exposes them to deposited lead more frequently than other dabbling species, ex- cepting the black duck, which behaves sim- ilarly. Redheads (13.57), ring-necked ducks (14.18), canvasbacks (11.84), and lesser scaups (13.09) normally dive for food in comparatively shallow water in_ their search for seeds, tubers, and rootstocks of aquatic plants. Plant items, according to Cottam (1939:53), make up 60 to 90 per cent of the food of these ducks. The combined effect of feeding in heavily shot- over waters and the types of food taken result in a higher frequency of ingested shot pellets in this group of diving ducks than in any other group or species of wa- terfowl. Regional Variations in Shot Inci- dence.—The incidence of ingested lead shot among ducks of 11 important species was determined for each of the North American flyways by examination of 39,- 610 gizzards collected in the fall and early winter months of 1938-1954, table 1% The incidence of ingested lead was lowest in ducks of the Central Flyway. There were only small differences be- tween the figures for North Dakota, South Dakota, Nebraska, and Colorado; for Texas the incidence of shot was sev- eral times as high as that for any other state in the flyway. In the Dakotas, only the shoveler, redhead, and canvasback showed an appreciable incidence of in- gested lead, whereas in Texas most spe- cies showed a high incidence of such lead. The incidence of ingested shot pellets was about twice as high among ducks of the Atlantic Flyway as among those of the Central Flyway, table 12. The inci- dence figures were higher for Massachu- setts, North Carolina, and South Carolina and Georgia than for Maine, New York, 262 a group of other Atlantic states, and Flor- ida. With few exceptions, waterfowl giz- zards from the above states came from areas near or on the Atlantic Coast; most samples from New York and Florida Ittino1s NATURAL History SuRvVEY BULLETIN Vol. 27,-ArkS were from the interior areas of those states. Species in the Atlantic Flyway with the highest incidence of ingested lead shot were the pintail, canvasback, and redhead. Next in order were the mallard Table 12.—Regional incidence of ingested lead shot among ducks of 11 important species; the United States and Canada, 1938-1954. Matiarpd |Briack Duck} GaADWALL BALDPATE PINTAIL a>) is} ae] ry 5 = » ae 52) ee l\ae2| delet lta lst) see a: os aa ao: a's on fel S| se) eo | €e.e | 88.) ao ee zal\eelza|f2|2za\/S2 1/24) 82 | 24) ce ATLANTIC Mia inet ace, ade eminent 7 | 14.3 725 4.8 1 0.0 ee 13 15.4 Massachusetts........-..| -----Je+.-.- {l,268 TES) SS 4} 0.0 a0 Re 48 INewa ionic can oan Wal 6.5 425 4.5 1 0.0 12 | 0.0 32 12.5 Pennsylvania, New Jersey, Delaware, Maryland, WiReiNta Nee 59 7 207 2.9 14 | 21.4 5 0.0 13 61.5 North Carolina.......... 9 Tal ER oe oO 30 | 10.0 2 fall eto 50 4.0 18 0.0 South Carolina and Gedteian sa atiewe asst Wi 9.1 66 | 13.6 95 32 38 0.0 56 10.7 Wionida teen eer ie eke 3] 0.0 5 0.0 15 0.0 15 | 13.3 15 | 20.0 TEBTALR oes ee NE ce PE OU eee os COL nee 126 Seis ele: 1 ee Averase: an2> st incsiclhaee (ie as Be 6.1 ie i aS oe cn. MissIssIPPI Minnesota..............| 371 | 12.4 9} 11.1 18 5.6 23 | 0.0 102 12.7 Wlittigne cee er ee SRO a9 27 | 18.5 109 | 0.0 162} 00} 951 5.9 Tindiatiatce sisal a ee | 2385 93 | 28.0 13 | 0.0 17 5.9 34 11.8 Missouri.......-.-.-....{| 415 2.4 4 0.0 8 | 12.5 8 0.0 35 2.9 Tennessee...............| 696 | 11.6 17 5.9 174 1.2 38 5.3 102 4.9 Arkansas...............|3,494 2 AE ae SR rel Awe be Bid Lo See Wouisiana. 2228. oe. |) B19) 15.1 7 | 0.0 17 eee: 38 Ded 160 | 28.1 Ota acta ery ALO OU cps eta) uate seen 449 ...| 286 . | ([3040 | een IANPRAE Cy # See ere ane c| meee S24 eae ol 21e 0 cay 1260). cn a ee 9.0 CENTRAL North Dakota.........../1,186 1.9 171 0.6 74 1.4 161 0.6 South Dakota...........|1,123 2.6 9] 0.0 13 | 0.0 26 0.0 INebraskateres ter ee a Uae oD a oni 2! 0.0 63 | 0.0 8 0.0 @oloradon wet el 2OON i Oe 7 Ea 1 leans Wi lite Shiga re Me xas sn weaten Seale Aen 65 | 15.4 18 | 11.1 25 | 0.0 51 15.7 POW eS ee tee SR OLS, eI? 200 Steal UZ One (uate 246 a Average: Staaten batensse Our rete) der bititorsee 0..61|Sgeae K PAaciFic British Columbia........| 138 | 17.4 2! 0.0 37 | 0.0 55 16.4 Washineton.. 0. 5. .<..-.'s| , 398 5.0 6 0.0 120 1.7 118 11.0 Wresonties 2. Soe ns! 214 | 4.7 Os) “040 S7y| 7207) 0z 7.8 Tdahose ete soe es ee [23502 5.8 ee Gea 29 | 3.5 23 13.0 Weahwencissen en eel O86 12.5 285 2.1 451 3.8 |2,776 7.9 INevidaleemaos eek. 30 | 20.0 22 0.0 7 0.0 25 12.0 California...............| 697 7.4 158 1.3 | 383 | 4.7 |1,596 9.9 Ota ahaha See ee Sa OG OD ||| ae 482 1,084 4,695 |S Awe ero Hite gs dia exes leh oe 8.8 Ne 8. May, 1959 and the lesser scaup, the black duck, and the ring-necked duck. The incidence of ingested shot among ducks of the Pacific Flyway was only slightly higher than that found in the At- BELLROSE: LEAD PoIsoNING IN WATERFOWL 263 lantic Flyway, table 12. Ducks near Van- couver, British Columbia, showed a higher incidence of ingested shot than did those in any other area of the flyway. In con- trast, ducks in adjacent Washington data are from 39,610 gizzards collected during fall and early winter months from hunters in GREEN- Rinc-NeEcKED | Lesser To Mieecen TEAL SHOVELER REDHEAD Bows CANVASBACK | Secatre pea oS > gal ee 2 tl eet 52a es al age Ue ret Paes el ees ga) ga) s2|a|e2| a | ee| gal s2| ba | 52) 84 | 52 | ga €6/9s (eS |Ss| E85 | Ss] EFlSS| SELSS| EE PS] EE] Ps eel 53 St 5 > | eo S BS | pe = cS et = nt Za\@e lad | PE | ze) ee | za | SE | 2d | SE | 2a) SS | 28 | Se | | | 99 | 3.0 90 | 3.3] 40| 7.5] 975] 48 1540 '6.7 oe eae SOOO. ecb 7 2 Seaea ie ages 551 1.8 66| 6.1 91° 0:0:| 27} 18:4} 213) -s.0:) SH) S28 aS) 2.6 |. ral a. mn) 5 | 20.0 4} 0.0| 349} 5.7 Ba =3.0. 68 | 11.8 4| 0.0} 93] 11.8 51 0.0| 301) 83 42 | 2.4 a} 030.4. 61} 9.8 L}) O01). 5 30.0) 460F aa 12} 0.0 54.020 |. 25} 4.0 2} 0.0 6| 0.0} 103} 5:8 204 13 |. Rie en Po jae bo Naga, ee eas ee Ree: 2 ek Mite tee. PI a Ae Gs iiseb te 13! 00| 40] 2.5] 44/15.9| 79|29.1] 132| 4.6] 88]12.5| 924] 11.8 Panjees} 60) 0.0| 1513.3} 120|17-5| 224| 7.6} 451} 11.5 17,778] 7.3 fes%| 12 | 0.0 7114.3| 50|26.0| 16| 0.0] 20] 20.0| 526| 205 56 | 0.0 9} 0.0 8|12.5| 20] 10.0 3) 0:0)] (32 | 0351 | 598 fa ees | 18) 11.1 4] 0.0| 266} 14.7| 31] 16.1] 95 | 23.2 \1,504| 9.3 eee shoe | ae Bot) Motes inl eae f eee oe ee ee ee 7} 38} 13-| 0.0 70| 7.1} 7| 0.0} 107] 26.2 |1,005| 14.0 me ise |...) 78 |..2-.-| > 605 |....5.| 403 793|......|15,829 mee £7 4......| 2.0 A ee THO ORY 6 1s EES eee eee 9| 0.0} 29| 0.0] 90} 7.8 SP 9 S21 47 1-9 2 SE boo mr -o.0| 18] 5.6} 20| 0.0 SP ao | ts) 77. 33 | OO) we MO 0 |. ....:|.-.. a | | 0.0| 24] 4.2 11,406] 2.8 ee igs ey eden oc OE tte aetna | eeciage Mania, (emer OME. Kr a 11] 9.1 7114.3 | 194 110.3.) 25. -8.0:| 41 25.0)— 30 3.3 |. 430 |- 40.7 meee S54)... | 304 |..ok.| 30 222 |......| 134 | 5,368 Mette | 3.7 |......| 8:9 CA aoa Meee | 7a ieee (ae. 29} 0.0 25) SOTO gina eae fe Dims hE Wh ieee Mee Mie 7a ee Mer ae 125| 0.0 7 | 0.0 6 | 16.7 Seto | 7 13 8|25.0| 998| 4.9 Beet) 110°/90.0)..2..-|.....| 1} 0.0 4|25.0| 4| 0.0| 442] 5.7 7] 0.0 1| 0.0 SAC ECE, eM rem Nite a Wate Mee Oy TS mor) 0.5) 791 | 1.0| 209] 23.4|......].......| 793111.9} 13| 7.7 17,605] 7.1 i 00| ~46| 2.2 4 | 25.0 1} 0.0 6|33.3} 11 0.0]. 167i. 73 Sener | 9650:| 147 | > 54) 5.6.|......|--....| 68] 21.3] 15] 0.0-]3,895) 6.7 mean9 |... ...\1;507 |......| 274 |.... 6 ed eee eee y al eee Fo | ees ae 7 Cee We 19.7 |. Ee AG aS etal Gag 264 Ittinois NATURAL History SuRVEY BULLETIN Vol. 27, Art. 3 Table 13.—Incidence of ingested lead shot among ducks of 10 species at Hovey Lake, near Mount Vernon, Indiana; of 1949, 1950, and 1951. the data are from gizzards collected in the waterfowl hunting seasons 1949 1950 1951 Peace Number | Per Cent | Number | Per Cent | Number | Per Cent Examined | With Shot | Examined | With Shot | Examined | With Shot Mallard. serene eee 90 35.6 56 12.5 61 9.9 Blackcduck<.c.cc Soe coe 39 43.6 18 16.7 19 15.8 Ee tae alt 4g 5 0.0 5 0.0 3 0.0 Baldpate. . RR I AR 4 0.0 3 0.0 4 0.0 Pintail. . a SD ese 17 5.9 6 0.0 3 0.0 Green- winged teal. Seats i 0.0 3 0.0 2 0.0 Shoveler. . eee © 2 0.0 y) 0.0 7 0.0 Ring- necked duck. . Rute 15 46.7 16 5.9 10 20.0 Canvasback.. Ue ee Feit ee 4 0.0 6 0.0 5 0.0 eee ee ee 4 25.0 6 0.0 7 28.6 5 AT Ree ARS CPt rane a a hage er 187 be ice bt 121 ees EZ yay Averane rumen een ce pale seeo tee Sie SRC ee tiniest ql se 10.7 showed the lowest incidence of shot for the flyway ; gizzards collected from Wash- ington were from numerous areas scat- tered over the state. Among the ducks of Utah and Nevada, the incidence of ingested shot was slightly greater than the average for the flyway. Among the ducks of Oregon and Idaho, the incidence figure was below the flyway average. The incidence figure for the ducks of California approximated the fly- way average. The data from Utah were obtained from material collected at the Bear River Migratory Bird Refuge; the data from Nevada were obtained largely at the Stillwater Wildlife Management Area. Material from Oregon, Idaho, and California were from numerous, widely distributed areas. In the Pacific Flyway, the incidence of ingested shot was highest among the red- head, canvasback, and lesser scaup, lower in the mallard and pintail, and still lower in the baldpate, gadwall, shoveler, and green-winged teal. The incidence of ingested shot was Table 14.—Incidence of ingested lead shot among ducks of 12 species in Illinois ; the data are from gizzards collected in the fall months, 1938-1953, from waterfowl hunters i in the Illinois and Mississippi river valleys. Ittino1s River Mississippi River SPECIES Number Number | Per Cent | Number | Number | Per Cent Examined | With Shot | With Shot | Examined | With Shot | With Shot Meallird sorte as ok eos 4,784 405 8.47 475 7 1.47 id Tab ene as Can cages 104 0 0.00 5 0 0.00 Baldpate. . 154 0 0.00 8 0 0.00 Pintail. . 920 52 5.65 31 4 12.90 Green- winged teal. 373 3 0.80 27 0 0.00 Blue-winged teal... tc ee 121 1 0.83 8 0 0.00 ine A ee ee 57 0 0.00 3 0 0.00 Wood duck. . A oh ee Te 19 0 0.00 7 0) 0.00 Redhead... .. Pe he 12 2 16.67 2 0 0.00 Ring-necked duck. . oo 113 19 16.81 7 2 28.57 Canvasback.. re Sey a 88 10 11.36 136 i 5.15 Lees Ss eee aa 144 34 23.61 307 18 5.86 Tala epee ee ee 6,889 526 Bagh 1,016 38 ig IASEEAGR a RNR ecitoup es mec hid nis eae oe 64 Batak og nes 3.74 May, 1959 higher among ducks of the Mississippi Flyway than among those of any other flyway, table 12. The highest incidence figure for the Mississippi Flyway was for ducks taken in Indiana; these figures were not typical for the state, as the bulk of the samples on which they were based were from Hovey Lake, near Mount Vernon. Hovey Lake is noted for lead poisoning losses in waterfowl. The incidence of ingested shot was high among the ducks of Louisiana and Minnesota; moderately high for those of Illinois, Tennessee, and Arkansas; and quite low for those of Missouri. The gizzard collections from Minne- sota, Illinois, and Missouri constituted representative samples for those states. In ‘Tennessee, almost all the data were from Reelfoot Lake. In Arkansas, the giz- zards were from ducks shot at clubs with- in a 35-mile radius of Stuttgart. Both Reelfoot Lake and the Stuttgart area provide a large share of the duck hunting in their respective states. Material from Louisiana was largely from Catahoula Lake and the Delta region of the Mis- sissippi River. In the Mississippi Flyway, the inci- dence figure for lead shot was higher in the black duck than in any other species, but the data were biased by the large number of black duck gizzards taken at Hovey Lake, Indiana, where the _inci- dence of lead was extremely high. It was very high in the ring-necked duck, lesser scaup, and redhead; it was moderately high in the pintail, mallard, and canvas- back; it was low in the shoveler, green- winged teal, gadwall, and baldpate. The variation in the proportion of ducks with shot in their gizzards at Hovey Lake was very pronounced over a 3-year period, table 13. In 1949, the highest in- cidence of ingested shot found anywhere in the United States was recorded at Hovey Lake, but in 1950 and 1951 the figure for the area was close to the aver- age for the Mississippi Flyway. The extremely high incidence figures for Hovey Lake in 1949 were probably influenced by the hunters’ kill of a large number of ducks affected by lead poison- ing. Up to the end of the 1949 hunting season, the Indiana Department of Con- servation permitted hunters to jump-shoot BELLROSE: LEAD PoIsONING IN WATERFOWL 265 ducks. Since that time, duck hunting at Hovey Lake has been restricted to blinds. Jump shooters, in wading the brush-cov- ered shore of Hovey Lake, hunted a zone in which ducks suffering from lead poi- soning were prone to concentrate. Be- cause the sick ducks had difficulty in fly- ing, hunters bagged unusually large num- bers of them. A reduction in the incidence of ingested lead occurred in the mallard in 1951 at Hovey Lake, evidently because high wa- ter, which raised the lake level during the latter part of the hunting season, made lead shot less easily available to this duck. The increased depth failed to reduce the ingestion of shot by diving ducks. A comparison of the incidence of in- gested shot in ducks taken along the IIli- nois River with those taken along the Mississippi River in Illinois, table 14, disclosed a marked difference between the two areas. The figure for the [Illinois River is more than twice that for the Mis- sissippi. The differences in shot incidence between the two areas were especially marked in the mallard, canvasback, and lesser scaup, the only species that were represented by adequate samples in both areas. The Mississippi River normally car- ries a much heavier load of sediment than does the Illinois River. Data presented by Suter (1948, plate 1) for the period 1935-1945 showed that the Illinois River at Peoria carried an average of 100 p.p.m. for 300 days per year, whereas the Missis- sipp! River at Quincy carried an average of almost 300 p.p.m. for the same number of days. Apparently lead shot is covered more quickly in the Mississippi, with its heavier load of sediment, than in the IIli- nois. Periodic Variations in Shot Inci- dence.—The incidence of ingested lead shot in mallard populations migrating through the Illinois River valley in au- tumn was determined for weekly periods by examination of 2,499 gizzards collected from hunters in 1938—1940, table 15. As in the case of mallards which were live-trapped and fluoroscoped, table 8, the percentage of hunter-killed birds that car- ried ingested shot was: lower early in the season than late; up to mid-November, 5.7 per cent of the gizzards examined con- 266 tained shot, while after mid-November 7.8 per cent contained shot. The incidence of shot among hunter- killed birds, table 15, varied from week Table 15.—Periodic incidence of ingested lead shot among mallards in Illinois; the data are from 2,499 gizzards collected from water- fowl hunters in the Illinois River valley, 1938- 1940.* NuMBER OF PERIOD GIzzARDS Per Cent EXAMINED Wirxu SHot Oct. 11-17... 82 2.44 18-24... 227 7.05 25-3 ibs. a 456 3.73 Nove nd / anes Sui 8.75 8-14.... 296 4.73 15-21... 455 7.69 Ds) Rages aes 324 9.88 Nov. 29-Dec. 5. 216 7.41 Dec. 6-12.. 66 0.00 *Data from food habits study of Illinois ducks by Harry G. Anderson, June 1, 1939—June 30, 1941, leader of Federal Aid Project 2-R, Illinois Natural History Survey and Illinois Department of Conservation, co- operating. It~tinois NaturAL History SurRvEY BULLETIN Vol. 27, Art23 Bear River Migratory Bird Refuge, Utah, are given in table 16. Ingestion of shot was uncommon during the summer months, except for the mallard in 1951, but it was relatively common for several species in the fall. It is evident that much of the lead in- gested by ducks in Illinois and in Utah had been fired from hunters’ guns in the same year it was picked up by the ducks. Apparently, much of the shot fired by duck hunters during a hunting season penetrates sufficiently deep into lake and marsh bottoms by the following summer to be out of reach of feeding waterfowl. Data in table 11 and those reported by Shillinger & Cottam (1937:401) permit a comparison of the incidence of ingested lead among waterfowl in two periods sep- arated by more than 20 years. According to Arnold L. Nelson (letter, December 13, 1955), 77 per cent of the gizzards re- ported on by Shillinger & Cottam were collected in the period 1908-1916; all gizzards represented in table 11 were col- Table 16.—Incidence of ingested lead shot among ducks of seven species at or near the Bear River Migratory Bird Refuge, Utah, summer and fall, 1950 and 1951. Summer data are based upon fluoroscopy of ducks apparentiy suffering from botulism; fall data are from duck gizzards collected from hunters. SPECIES WIR eaten! es Rae BUR Sm myer Pi ere kite Gad allt eee en enti eee NU er: ne ana NS Brcelrsette eee ree ee eens a gmt dcr Mi Enea a AAS ea hae Nlhreld Rapee a eRe Green-wingediteal: o..5 1 0i tube eows.. ook Sears pet 1) ots rate ger anne | PREYS HA Cee Ys Weil ane Ly reel I AL) nN IVER AGS ssi tals Shaan nee Cec orate ee eerie ARR 1950 1951 Per Cent With Shot | Per Cent With Shot Summer Fall Summer Fall 3.2 on 14.3 8.9 0.0 0.7 Oe PD 0.0 3.2 0.0 3.9 0.6 10.0 0.6 5.8 0.0 0 2 0.0 0.2 1.8 0.9 0.0 1.1 0.0 PALL 0.0 pcyee? 0.8 6.7 0.7 5.6 to week as in live-trapped mallards, table 8. In Minnesota, as in Illinois, a pro- nounced weekly variation in the incidence of ingested lead has been reported (Reid 1948:126). These periodic variations in the incidence figures appear attributable in part to population shifts associated with migration. Figures on the occurrence of ingested shot among waterfowl taken during the summer and fall months at or near the Table 17.—Incidence of ingested lead shot among mallards taken in two different periods of years in the Illinois River valley; data are from gizzards collected from hunters. NuMBER OF YEARS GIzZARDS Numser | Per Cent ExamMInepD | Wirtu Snort | Wiru SHor 1938-1940] 2,371 165 6.96 1948-1950} 2,005 240 11.97 May, 1959 lected in the period 1938-1953. The comparison is limited to six species of ducks—mallard, pintail, redhead, ring- necked duck, canvasback, and lesser scaup —which are listed in both periods. In five of the six species (the exception, lesser scaup), the incidence of ingested shot recorded for the 1938-1953 period, table 11, was much higher than that for the earlier period. The per cent of giz- zards containing shot increased for the five species as follows: mallard from 2.41 to 6.79, pintail from 1.14 to 8.87, redhead from 3.14 to 13.57, ring-necked BELLROSE: LEAD POISONING IN WATERFOWL 267 duck from 3.29 to 14.18, and canvasback from 9.77 to 11.84. Shillinger & Cottam (1937:401) re- ported lead in 39.42 per cent of the lesser scaup gizzards, but over one-third of their sample was from the vicinity of Mar- quette, Wisconsin, where shot was found in 76.5 per cent of the gizzards. The large sample from an atypical area mate- rially biased the results. The incidence of ingested lead among mallards in the Illinois River valley dur- ing two different periods—1938—1940 and 1948—1950—is shown in table 17. In a Table 18.—Incidence of various ingested shot levels found among ducks of seven species; data are from 2,184 duck gizzards (each of which contained ingested lead) collected during the fall and early winter months from hunters in North America, 1938-1954. (By shot level is meant the number of ingested shot pellets found in a gizzard.) For each species are given the number and per cent of ducks represented at each shot level. 1 PeEL- 2 PEL- 3 PEL- 4 PeEL- Seer 6 Pet- | Over 6 T LET LETS LETS LETS LETS LETS PELLETS eae SPECIES eu Rae les ies ica siccs uel Re Wiss | ee elie . w cee bee ote rosa ools | oalee he ens 3 5 } ay 5 5 3 5 B) 3} 3 5 5 G 3 i PZ || foby Neg MIS |g | fale ae foi | Za fom Ih ez | fet Pee | rau, NN Ie aw Mallard........| 757/65.3] 194)16.7} 80] 6.9} 31) 2.7] 24] 2.1 9| 0.8) 64) 5.5/1,159/100.0 Black duck..... 120/65.6| 27/14.8) 15} 8.2 6) 3.3 1) 0.6 3) 1.6} 11] 6.0} 183/100.0 Bintan se el 2eliGO.O) Suil2e 7 27) 6.7) 19 4: 7 19 350 1} 0.2} 51/12.7| 402]100.0 Redhead........ 56/69.1) 11/13.6 4, 4.9 0) 0.0 il] ill} il 8} 9.9 81)100_.0 Ring-necked aherCle. Se eeereme 6565.7} 10]10.1 9) 9.1 2) 2.0 0} 0.0 A OW aaah 99|100.0 Canvasback.....| 107/74.3} 13) 9.0} 12) 8.3 4| 2.8 1] 0.7 Sera 4, 2.8) 144/100.0 Lesser scaup.... 67/57.8) 19)16.4) 12/10.3 3) 265 0} 0.0 1] 0.9} 14)12.0} 116|100.0 center esl CASO | TOO), uc) OS). i OOo Tal Olas ok MOOI b, 2 || Qe OA Ih kes, al SCI eee Sea Ot leee all4te9 TV Bio Solo - 1.8 On9 Tele se LOOLO Table 19.—Incidence of high levels of ingested lead shot (20 or among ducks of seven species; data are from gizzards collected from more pellets in gizzard) North American hunters in the autumn and early winter months, 1938-1954. NumBer OF Gizzarps | NuMBER OF PELLets | Numper |Per Centr or Gizzarps SPECIES Wir PeEtvets IN INDIVIDUAL OF Wiru 20 or More GIzZARDS Ducks Pe.iets Eacu MWWallandya. <2 0s. « 4: 1,159 20, 60, 93, 107, 137 5 0.43 Black duck...... 183 MS 1 0.55 Pimizevtl 5 6 aes 402 PAO), PAD), PIA GIB). PIS) Bhsts 9 2.24 48, 60, 110 Redheads...« 452 81 RE NERO fa Bina ee ee 0 0.00 Ring-necked duck 99 Sil, 7 (S 3 3.03 Canvasback...... 144 53 1 0.69 Lesser scaup..... 116 21, 21, 43, 46, 52, 58, 8 6.90 64, 172 TNOWAIGS cues 2,184 27 aT AC OTD Ae ee Sf SME, ao ae Bharti: shares 1.24 268 Ittrnoris NaturRAL History SurvEY BULLETIN decade, the incidence figure for Illinois mallards almost doubled. Increases in the percentage of water- fowl ingesting lead have paralleled in- creases in the number of waterfowl] hunt- ers. Because there is expectation that the number of duck hunters will continue to increase, it can be anticipated that lead poisoning will become a greater hazard to waterfowl] than it is at present. Incidence of Various Shot Levels. —The incidence of various levels of in- gested lead shot found among ducks of seven species in North America in the autumn and early winter months of 1938-1954 is shown in table 18 and fig. 6. (By level of ingested lead shot, or shot level, is meant the number of ingested shot pellets found in a gizzard.) The va- rious shot levels have an important bear- ing on the rate of mortality in ducks for, as will be shown later, the larger the num- ber of ingested shot pellets per duck, the higher is the death rate, other factors be- ing equal. Of 2,184 duck gizzards that contained lead when collected from hunters in many parts of North America in 1938-1954, i fa RRS DAD ADS DROS NDAL A ORDEN ANAD tek SN NE RE AN Re ie PER CENT OF SPECIES Seer acc oa aie i yy Y YQ Bg ee Yy) ea Vy pate Yj ae G bo G fee Y ae Y) be Y oe Yy oe Y aa Z EY se Yj / Y Py Y) LY Ly A g ny PELLETS pau . WZ PELLET, Vol. 27, Art. 3 64.7 per cent contained one pellet each, table 18; 14.9 per cent contained two pellets each. Only 7.4 per cent of the gizzards containing shot pellets contained more than six pellets each. Comparatively few ducks killed by North American hunters during the fall months in the period 1938-1954 carried 20 or more ingested shot pellets each, table 19. The maximum number of pellets re- corded was 172, in a lesser scaup gizzard. Cottam (1939:39) reported 1 to 58 pel- lets in individual gizzards of lesser scaups shot near Marquette, Wisconsin, in April, 1909; Shillinger & Cottam (1937:403) reported that 179 pellets were found in the gizzard of a pintail victim of lead poi- soning. Data in table 19 indicate that pintails, ring-necked ducks, and lesser scaup ducks are more likely to have large numbers of pellets per gizzard than are the ducks of other species. The large numbers of shot pellets found in gizzards of pintails, ring-necks, and lesser scaups are probably a reflection of the ability of these species to tolerate the toxic effects of lead, as well as a reflection MALLARD BLACK DUCK PINTAIL REDHEAD ° RING-NECKED DUCK CANVASBACK LESSER SCAUP 3 PELLETS Fig. 6.—Incidence of four levels of ingested shot found in gizzards of ducks of seven species in the autumn and early winter months of 1938-1954. Data are from table 18 and represent ducks shot by hunters in many parts of North America. May, 1959 of their proclivity to pick up large num- bers of pellets. For example, pintails are only slightly more prone than mallards to ingest shot, table 11, but the percentage of gizzards containing 20 or more shot pellets each was almost six times as great in pintails as in mallards, table 19. The percentage of gizzards containing ingested shot was about the same in_ redheads, ring-necked ducks, canvasbacks, and lesser scaups, table 11, but larger percentages of BELLROSE: LEAD POISONING IN WATERFOWL 269 LEAD IN WILD MALLARDS DOSED AND RELEASED Certain effects of lead poisoning on mallards in the wild were determined by the following experiment. In the au- tumns of 1949, 1950, and 1951, several thousand migrating mallards were trapped at Lake Chautauqua. Some of these ducks were dosed with either one, two, or four No. 6 shot pellets each, then banded, and Fig. 7.—Penned mallards, dosed with lead shot, feeding upon coontail, apparently one of the best vegetable foods for alleviating the effects of ingested lead. gizzards with 20 or more shot pellets each were found among the ring-necked ducks and scaups. As shown by Jordan & Bellrose (1951: 18), the ability of ducks to survive lead poisoning is influenced by the physical form of the food consumed. The higher survival rate of pintails than of mallards may be related to the greater numbers of small seeds and the paucity of corn in the diet of the pintails. Lesser scaups, which consume at least twice as much animal life per bird as any other ducks listed in table 19 (Cottam 1939:53), apparently can tolerate lead to a greater degree than the ducks of other species. Thus, it ap- pears that animal matter is more favora- ble than vegetable matter to survival of ducks that have ingested lead, and that various forms of vegetable matter differ greatly in their effects on birds that have ingested lead, fig. 7. released. Other ducks trapped at the same time were banded and released, undosed, to serve as controls. In 1949 and 1950, the trapped mal- lards were taken to the Havana field lab- oratory of the Illinois Natural History Survey, where they were fluoroscoped be- fore being banded and released. Ducks known to carry ingested lead when trapped were not included in the experi- ment. In 1951, when the X-ray unit was being repaired and could not be used for fluoroscopy, undoubtedly some ducks car- rying ingested lead when trapped were released as dosed or control birds. The number of these was, of course, unknown but it was probably relatively small. In 1949, only adult mallard drakes were included in the experiment. In 1950 and 1951, both adult and juvenile drakes and, in 1951, hens also were included in the experiment. 270 ILLINOIS NATURAL In 1949, 559 mallards were dosed with one No. 6 shot pellet each before being released, and 560 lead-free birds were re- leased, undosed, to serve as controls. Of the 1,172 mallards used in the experiment in 1950, 391 were dosed with one No. 6 pellet each, 392 were dosed with two No. 6 pellets each, and 389 were released, un- dosed, to serve as controls. In 1951, 2,016 mallards were used as follows: 504 drakes were dosed with one No. 6 pellet each, 504 drakes were dosed with four No. 6 pellets each, 501 hens were dosed with one No. 6 pellet each, and 507 drakes were undosed. Because of the considerable cost of han- dling the mallards used in this experi- ment, it was deemed advisable to obtain reports of as many band recoveries as pos- sible from the hunters who shot the birds. As an inducement to hunters to report bands, 759 ducks released in 1949 were banded with U. S. Fish and Wildlife Service reward bands (which provided a certificate and booklet for each person re- turning one or more bands); 360 were marked with standard Fish and Wildlife Service bands. In 1950 and 1951, each mallard in the experiment was banded with a special $2.00 reward band, as well as the standard U. S. Fish and Wildlife Service band. The ratio of reward to standard bands recovered was more than 2 to 1 (Bellrose 1955). Bands recovered from the mallards used in the experiment revealed signifi- History Survey BULLETIN Vol. 27, Art. 3 cant differences between the dosed and the control birds. The dosed birds, some of which became afflicted with lead poi- soning, had (1) a greater vulnerability to hunting, (2) lower ability to migrate, and (3) higher over-all mortality rates in the first year after being banded and released (from time of banding through the fol- lowing August). Effect of Lead on Vulnerability to Hunting That mallards carrying lead in their gizzards were more vulnerable to hunting than were lead-free mallards is shown in tables 20-23. In 1949, mallards dosed with one No. 6 shot pellet each were 1.84 times as vulnerable to hunting as were the controls, table 20. In 1950, they were 1.19 times as vulnerable, and, in 1951, they were 1.41 times as vulnerable. The year-to-year variation in vulnerability probably resulted from differences in food and weather conditions. Unfortunately, the effect of two and of four No. 6 shot pellets for each bird was evaluated for only 1 year. In 1950, the kill rate of mallards dosed with two No. 6 shot pellets each was 1.89 times as great as the kill rate among the controls, table 20. A year later, the kill rate among mallards dosed with four shot pel- lets each was 2.12 times as great as the kill rate among ducks not dosed with shot. During the first 5 days after the mal- lards in the experiment were released, Table 20.—Relative hunting vulnerability exhibited by wild drake mallards dosed with lead and those not dosed, as measured by the ratio between dosed and undosed birds in the per cent of the banded ducks that were recovered in the season of banding. The 3,807 drakes used in the experiment were trapped at the Chautauqua National Wildlife Refuge, near Havana, Illinois, in the hunting seasons of 1949-1951. Some of the birds were banded, dosed with one, two, or four No. 6 lead shot pellets each, and released. Others, the controls, were banded and released undosed. NuMBER NuMBER Per Cent BANDED RECOVERED RECOVERED RELATIVE. VULREOR Eee Dosep : ContrRoL Y Pellet Pellet Pellet rae Con- Dose Con: Dose Cone Dose trols ttOlSiis—aae | trols 1 2) 4 1 2 444. 1 os 4 1 Pellet | 2 Pellets | 4 Pellets 1949. .| 560} 559). ..|. 19] 35 SPS9IGL25heaelee eel s4eOONe ‘uo on 1950. .| 389} 391/392) .. 50} 60 95 12.85}15.35|24.23) ....| 1.19:1.00 1.89:1.00 |. a ee 1951..| 507} 504) . |504! 47) 66 99} 9.27/13.10) ... |19.64! 1.41:1.00}. . 2.12:1.00 Total |1 ,456\1,455|392|504| 116\161| 95| 99 |. ee | May, 1959 BELLROSE: LEAD PoIsoNING IN WATERFOWL 271 the birds treated with lead were bagged at about the same rate as the untreated controls, tables 21-23. During the sub- sequent 6—10-day period, there was a pro- nounced increase in the bag of treated ducks, especially in those dosed with two or four shot pellets each. In the dosed wild mallards, the inges- tion of lead shot did not appear to affect behavior until after the first 5 days. In the mallards that were dosed with one shot pellet each, and that did not die of lead poisoning, the behavior appeared to be most severely affected in the 6—15-day period after ingestion; in mallards that were dosed with two or four shot pellets each, and that survived, the period in which behavior was severely affected ap- peared to be longer. The data suggest that most wild mallards that become af- fected by lead poisoning during the hunt- ing season either die in the second or third week following ingestion of shot or they begin their recovery by the early part of the fourth week. Penned wild mallards that were dosed with lead exhibited weakness and fatigue during the second and third weeks after being dosed; these symptoms increased in severity during the third and fourth weeks (Jordan & Bellrose 1951:5-6). The keel bone became prominent, and often the Table 21.—Relative hunting vulnerability exhibited by wild drake maliards dosed with one No. 6 lead shot pellet each and those not dosed, as measured by band recoveries in each of six periods, fall and early winter, 1949-50. The data are for birds trapped, banded, and released at the Chautauqua National Wildlife Refuge in the fall months of 1949; 559 of the birds were dosed and 560 were not dosed. 0 PELLET 1 PELLET Tora. E Number | Per Cent | Number | Per Cent | Number | Per Cent Days Arrer Dosace of Bands | of Bands | of Bands | of Bands | of Bands | of Bands Recovered | Recovered | Recovered | Recovered | Recovered | Recovered in Period | in Period | in Period | in Period | in Period | in Period as. 5 45.5 6 54.5 11 100.0 6-10. 2 28.6 5 71.4 7 100.0 = 15: 1 Lisi 8 88.9 9 100.0 16-20. 4 S77 <1 3 42.9 7 100.0 21-25. 2 50.0 2) 50.0 4 100.0 20: 4 ee 5 45.5 6 54.5 11 100.0 Total 19 30 49 Table 22.—Relative hunting vulnerability exhibited by wild drake mallards dosed with one or with two No. 6 lead shot pellets each and those not dosed, as measured by band re- coveries in each of six periods, fall and early winter, 1950-51. The data are for birds trapped, banded, and released at the Chautauqua National Wildlife Refuge in the fall months of 1950; 391 were dosed with one pellet each, 392 were dosed with two pellets each, and 389 were not dosed. 0 PELLET 1 PELLET 2 PELLETS Tora Days AFTER Number | Per Cent | Number | Per Cent | Number | Per Cent Number | Per Cent Dos- of Bands | of Bands | of Bands | of Bands | of Bands | of Bands | of Bands | of Bands AGE | Recovered | Recovered | Recovered | Recovered | Recovered | Recovered Recovered | Recovered in Period | in Period | in Period | in Period | in Period | in Period | in Period | in Period “0-5 : i 8 38.1 6 : 28.6 7 833 21 100.0 6-10. 3 13.0 8 34°8 12 5D) a 98 100.0 11-15. 7 21.9 8 25.0 17 Bei 32 100.0 16-20 . 6 Dee 5 18.5 16 59.3 27 100.0 21-25 4 36.4 3 Dijiee) 4 36.4 11 100.0 26-60 . 5 33).3 ii 46.7 3 20.0 1S 100.0 Total. . 33 37 59 129 272 Ittinois NatuRAL History SurvEY BULLETIN Vol. 27, Art. 3 Table 23.—Relative hunting vulnerability exhibited by wild drake mallards dosed with one or with four No. 6 lead shot pellets each and those not dosed, as measured by band re- coveries in each of six periods, fall and early winter, 1951-52. The data are for birds trapped, banded, and released at the Chautauqua National Wildlife Refuge in the fall months of 1951; 504 were dosed with one pellet each, 504 were dosed with four pellets each, and 507 were not dosed. 0 PELLET 1 PELLET 4 PELLETS TOTAL yive ——— eee “= =| —— —j|— - AFTER| Number | Per Cent | Number | Per Cent | Number | Per Cent | Number | Per Cent Dos- | of Bands | of Bands | of Bands | of Bands | of Bands | of Bands | of Bands | of Bands AGE | Recovered| Recovered | Recovered | Recovered | Recovered | Recovered | Recovered | Recovered in Period | in Period | in Period | in Period | in Period | in Period | in Period | in Period “i ae 29.0 i 35.5 i 35.5 31 100.0 6-10. 4 11.4 9 35 7 22 62.9 35 100.0 11-15. 7; 16.3 10 2313 26 60.5 43 100.0 16-20 . 6 29.2 8 29.7 13 48.1 OF 100.0 21-25 . 4 30.8 6 46.2 3 28 13 100.0 26-60 . 7 25.0 11 39.3 10 3507, 28 100.0 Total. . 37 br eee 55 ihe a eras 85 esti an Wire wings of an affected duck assumed a_ cated by differences in miles traveled by “roof-shaped” or drooping appearance. groups of mallards undosed and by sim- Symptoms typical of those found dur- ilar groups of mallards dosed with one, ing the fourth week in penned birds ap- two, or four No. 6 shot pellets each, ta- pear in wild ducks mainly at times of se- bles 24-26. In 1949, a group of mallards vere die-offs. Apparently, at other times, dosed with one shot pellet each had a affected ducks either recover or are taken’ larger percentage of its bands recovered by hunters or predators in a shorter period within a 50-mile radius of the banding of time and in a less extreme state of station than had the undosed control emaciation. group, table 24. In 1950, a group of mal- : ; lards dosed with one pellet each had a Effect of Lead on Migration Rate somewhat smaller percentage of its bands That lead poisoning has a pronounced’ recovered within the 50-mile zone than effect upon the migration of ducks is indi- had the controls, but a group of mallards Table 24.—Effect of ingested lead shot on migration of mallards, as measured by distances traveled by dosed and by undosed birds before they were shot by hunters. The data are for birds trapped and released at the Chautauqua National Wildlife refuge in the fall months of 1949; 559 of the birds were dosed with one No. 6 shot pellet each and 560 were not dosed. Figures show for dosed and for undosed ducks the per cent of recovered bands (those re- covered in year of banding and for which distance data are available) that were recovered at various distances from the point of banding and release. 0 PELLET 1 PELLET : Number Per Cent Number Per Cent Mites From Piace oF Banpinc of Bands of Bands of Bands of Bands Recovered | Recovered Recovered Recovered in Period in Period in Period in Period (LY 0 fame AR anne « LN OURO Set oats eure Meewne ere. 11 55.0 21 60.0 GT OOS at ate eee See ae Eee 1 5.0 1 2.9 LORS SO eae es ee ae os Pe a 2 0 0.0 0 0.0 LS DOO ne eae es recs i ane Tae Bi 4 20.0 1 2.9 DOE SOOR ek eRe ean oid ea ede oa ee ae 3 15.0 5 14.3 SOLA a alt ae a We te Ba Sie NEE RAT a AE 1 5.0 7 20.0 BV ATO EL. 2 FRED rhe, ate ese te aera te 0 0.0 0 0.0 TOBA ea ete Ce Vn eR: 20 100 0 35 100.1 _— May, 1959 dosed with two pellets each had a much larger percentage of its recoveries fall within the 50-mile zone than had the con- trol group, table 25. In 1951, one shot pellet for each bird seemed to have little effect on migration, but four pellets for each bird greatly retarded migration. Less than 5 per cent of the bands recovered from the mallards dosed with four pellets each were taken farther than 50 miles from the banding station, table 26. Manifestly, the weakness and _ fatigue movement BELLROSE: LEAD POISONING IN WATERFOWL of ducks. 273 associated with lead poisoning reduces the The larger amount of ingested lead per bird, the greater is apt to be the reduction of move- ment by the affected segment of the popu- lation. In areas where lead poisoning is of outbreak proportions, it is reasonable to conclude that the bulk of the sick birds have picked up shot within their daily feeding radius, usually less than 50 miles. the Conversely, it can be assumed that only a small percentage of the ducks that have Table 25.—Effect of ingested lead shot on migration of mallards, as measured by distances traveled by dosed and by undosed birds before they were shot by hunters. The data are for birds trapped and released at the Chautauqua National Wildlife Refuge in the fall months of 1950; 391 of the birds were dosed with one No. 6 shot pellet each, 392 were dosed with two pellets each, and 389 were not dosed. Figures show for dosed and for undosed ducks the per cent of recovered bands (those recovered in year of banding and for which distance data are available) that were recovered at various distances from the point of banding and release. Q PELLET 1 PELLET 2 PELLETS Mites From PLace oF Number | Per Cent | Number | Per Cent | Number | Per Cent BANDING of Bands | of Bands | of Bands | of Bands | of Bands | of Bands Recovered | Recovered | Recovered | Recovered | Recovered | Recovered in Period | in Period | in Period | in Period | in Period | in Period USSU eaten tent aed eee na eee 14 58.3 16 B33 33 76.7 SU IO 0s senate a 1 4.2 0 0.0 | 253 VOID SO) eps ieee aie ce een ane 0 0.0 0 0.0 1 2.3 |S 9X0 Oise ate | 4.2 0 0.0 0 0.0 DNS (00 es eae eo ee 1 4.2 3 10.0 5 11.6 UE AOC may es tot ace 7 29.2 11 56m. 3 7.0 POMGANGROVER: | kes cance foes 0) 0.0 0 0.0 0 0.0 Total... 24 100 1 30 100.0 43 909 9 Table 26.—Effect of ingested lead shot on migration of mallards, as measured by distances traveled by dosed and by undosed birds before they were shot by hunters. The data are for birds trapped and released at the Chautauqua National Wildlife Refuge in the fall months of 1951; 504 of the birds were dosed with one No. 6 shot pellet each, 504 were dosed with four pellets each, and 507 were not dosed. Figures show for dosed and for undosed ducks the per cent of recovered bands (those recovered in year of banding and for which distance data are available) that were recovered at various distances from the point of banding and release. Q PELLET 1] PELLET 4 PeLLets Mies From PLace oF Number | Per Cent | Number | Per Cent | Number | Per Cent BANDING of Bands | of Bands | of Bands | of Bands | of Bands | of Bands Recovered | Recovered | Recovered | Recovered | Recovered | Recovered in Period | in Period | in Period | in Period | in Period | in Period OF50. 2... 5. 36 69.2 51 67.1 94 95.9 S1=TCOG Seer ome a 4 thea 7 O)e) 0 0.0 {1C0)1 551 0 Ea eee Sere a 0 0.0 1 iL 8) 1 1.0 20m oa! 2) 3.9 4 58 (0) 00 201-300..... 4 Hea 7 9.2 1 1.0 BO400 2. a... ces 6 11.5 4 BES 1 1.0 401 and over.... 0) 0.0 2 2.6 1 1.0 LLG] a ee Tene 52 100.0 76 100.0 98 99.9 274 become ill from lead poisoning have mi- grated farther than 50 miles from where they ingested shot. Effect of Lead on Year-of-Banding Mortality Rate The mortality rates of the dosed and the undosed mallards in the year of band- ing or the first year (to end of following August) after being banded and released are indicated by data in table 27. Each I_tinois NATURAL History SurvEY BULLETIN Vol. 27, Art. 3 1950:8-12) as to have only a minor effect upon the mortality rates. Most of the year-of-banding mortality rates for the undosed, or control, groups in the experiment were lower than even the lowest of the year-of-banding mortal- ity rates for mallards reported by Bell- rose & Chase (1950:8—-12). In the Bell- rose & Chase study, a correction factor was used for bandings made during the hunting season, and mortality rates were Table 27.—The year-of-banding mortality rates of wild, free-flying mallards undosed and of similar mallards dosed with one, two, or four No. 6 lead shot pellets each. The data are for mallards trapped, banded, and released at the Chautauqua National Wildlife Refuge near Havana, Illinois. The mortality rates were derived as explained in the section entitled “Effect of Lead on Year-of-ERanding Mortality Rate.” “4 ies A Morva.ity Rate wis a Banp RECOVERIES (Per Cent) Spt PR way ee BanD RECOVERIES IN First 4 YEARS wo |A}A!] S| ga] Year or Banvinc Arrer BANDING ue 80 Scetsu ° Zz fy 7] Q Q x» os 7 S < 92 ay = aoe ee ies) Esc 08 < Zz 4 ra] 5 (S) Ds vop,ouvs mia a) o iq S32 ul J ee 6-50 S48 nm | a | a |zZQ | Number | Per Cent | Number | Per Cent al") ARAgY 1949....|M]} AJ] 0} 560 19 8139 143 25.53 1353 ee M|A 1 1s559 35 6.26 155 2173 2286 9.3 1950....|M]}AJ| 0] 278 33 11.87 106 38.13 Sila cee M|A Li}: 8274 45 16.42 103 3-9 43.7 1256 M|A 2 27 74 26.71 99 35.74 74.7 43.6 M | J Oct ah 17 15632 43 38 74 395 abet M| J 1 117 15 12.82 35 29.91 42.9 3.4 M| J 2 SEES 21 18.26 49 42.61 42.9 34 19ST MRA 011-300 24 8.00 77 25.67 31 2 Beebe: Mj; A Ls 24 42 12 96 91 28.09 46.2 15.0 M|A]| 4] 284 58 20.42 80 28.17 72.5 41.3 M | J Oer207 23 inert 13 3527 31.5 Shh Grea M | J 1 180 24 13.33 66 36.67 36.4 4.9 M | J 4 | 220 41 18.64 65 29.55 63.1 31 6 1939- 1943i | F 0 17,897) 390 4.94 1,094 13 85 35.6) <| Soee eee 1951.7...) EF D501 87 fei 151 30.14 57.6 22.0 *M=male; F=female. 7 A=adult; J=juvenile. tNo control hens were available at time of 1951 experiment; so recoveries for the first 4 years from bandings of hen mallards at the Chautauqua National Wildlife Refuge, 1939-1943, were used for the control data. mortality rate was derived by comparing the shrinkage in the population in the year of banding (as measured by year-of- banding band recoveries) to the popula- tion at the time of banding (as measured by the total band recoveries at the end of the fourth year after banding). For ex- ample, the mortality rate for adult un- dosed males released in 1949 was found by dividing 19 by 143, table 27. Al- though not all mallards of a banded group are dead by the end of the fourth year after being banded, the proportion of the group alive is so small (Bellrose & Chase calculated from the corrected percentages, rather than the numbers, of bands recoy- ered. In each year and in each sex and age class for which data were collected, the mallards dosed with lead shot had a higher mortality rate during the year of banding than the control, or undosed, mallards, table 27. For adult drake mallards dosed with one shot pellet each, in 1949, 1950, and 1951, the year-of-banding mortality rates were 9.3, 12.6, and 15.0 per cent, respec- tively, greater than the mortality rates for May, 1959 the controls. Adult drake mallards dosed with two shot pellets each in 1950 had a year-of-banding mortality rate that was 43.6 per cent greater than that of drakes of the same age class used as controls in the same year. Adult drakes dosed with four pellets each in 1951 had a year-of-banding mortality rate that was slightly, and unac- countably, lower than that of birds of the same sex and age class dosed with two pel- lets each in 1950. Juvenile drake mallards in 1950 and 1951 had lower year-of-banding mortality BELLROSE: LEAD POISONING IN WATERFOWL 275 for the undosed hens banded and released in 1939-1943. At the Rocky Mountain Arsenal, near Denver, Colorado, wild mallards were banded, dosed with lead shot, and released in late winter months, 1950 and 1951, by Johnson A. Neff and Charles C. Sperry of the U. S. Fish and Wildlife Service and Irving R. Poley of the Colorado De- partment of Game and Fish, table 28. Band data for 1951 were not used _ be- cause, as Neff (letter, February 5, 1955) reported, a chemical pollution of the water Table 28.—Number and per cent of bands recovered, 1950-1954, from mallards trapped, banded, and released at the Rocky Mountain Arsenal, Denver, Colorado, February 13—March 21, 1950. Before release, half of the males and half of the females were dosed with six No. 6 shot pellets each, and the others were released, undosed, to serve as controls.* NuMBER OF NuMBER OF Per CENT OF Sex SHor Dose Ducks Banps BANnpDs BANDED RECOVERED RECOVERED Male...... 0) 200 56 28.0 IMPAIE Se oe 6 200 19 9.5 [icranealtey aus aaah Oe eel ae atte 0 125 13 10.4 ienraleenkr ate te cea 6 125 12 9.6 *Experiments conducted by Johnson A. Neff and Charles C. Sperry of the U. S. Fish and Wildlife Service and Irving R. Poley of the Colorado Department of Game and Fish. rates than those of adult drakes dosed with the same number of pellets each. One group of juvenile drakes dosed with one shot pellet each and another group dosed with two shot pellets each in 1950 had year-of-banding mortality rates only 3.4 per cent greater than the rate for the controls. Juvenile drakes dosed with four pellets each in 1951 had a mortality rate that was 31.6 per cent greater than that of the juvenile controls but 9.4 per cent less than that of adult drakes dosed with the same number of pellets each in the same year. Because in 1951 no mallard hens were banded and released to serve as controls for 501 hens dosed in that year with one shot pellet each, no comparison of band recovery rates could be made between dosed and undosed females released in the same year. However, band recovery fig- ures were available for 7,897 undosed mallard hens banded and released in the period 1939-1943. The year-of-banding band recovery rate for the hens dosed, banded, and released in 1951 was 22.0 per cent greater than the recovery rate may have caused mortality which would bias subsequent band recoveries. Wild mallards were caught in the late winter months of 1950 and divided into two groups, each consisting of 200 drakes and 125 hens that at the time of capture were free of lead in their gizzards, as de- termined from fluoroscopy. The ducks were banded, those in one group were dosed with six No. 6 lead shot pellets each, and all were immediately released. The difference in band recoveries between the control and the dosed groups from the 1950 hunting season through the 1954 season provided an index to the magnitude of mortality caused by the ingestion of six No. 6 shot pellets per duck, table 28. If there had been no mortality from lead poisoning among the dosed mallards, the number of band recoveries in the sub- sequent hunting seasons would have been similar for the dosed and the undosed groups. The fact that there were almost three times as many band recoveries in subsequent hunting seasons from the un- dosed drakes as from the dosed drakes, table 28, suggests that the mortality ratio 276 between drakes that ingest six lead pellets each and those that ingest no lead is ap- proximately 3 to 1. The difference in band recoveries between undosed and dosed hens was so slight as to indicate lit- tle mortality from lead poisoning. An apparent reason for the large dif- ference in the mortality rates between the Colorado drakes and hens is that in late winter and early spring hens are less sus- ceptible than drakes to lead poisoning. Illinois experiments made with captive mallards under controlled conditions showed that during the spring hens are less susceptible to lead poisoning than are drakes (Jordan & Bellrose 1951:21). With the approach of the breeding season, the consumption of food by captive hens greatly increased until it exceeded that by captive drakes. Apparently the greater food consumption by hens during this par- ticular period was the primary factor re- sponsible for the greater survival rate of the Colorado hens. Illinois data suggest that, during the fall, hen mallards are much more susceptible than drakes to lead poisoning. The year-of-banding mortality rate for wild, free-flying mallard hens dosed with one No. 6 lead pellet each was about one-fourth greater than the highest year-of-banding mortality rate for mallard drakes similarly dosed, table 27. Among penned mallards, the mortality rate of hens was approximately double the mor- tality rate of drakes except in spring (Jor- dan & Bellrose 1951:21). As shown by differences in mortality rates between dosed and undosed birds, at each shot level tested juvenile drakes were much less susceptible to lead poisoning than were adult drakes, table 27. The lower susceptibility of the juveniles was more marked at the one- and two-shot levels than at the four-shot level. The greater food intake by juveniles seems to account for their lower susceptibility (Jor- dan & Bellrose 1951:20). There is good evidence that the drake class of the mallard population is com- posed almost equally of adults and juve- niles. The following mortality rates have been calculated on the assumption that the numbers of adults and juveniles are equal and that the percentages on which the rates are based (in farthest right column of table 27) hold true throughout Intino1is NAaTuRAL History SurvEY BULLETIN Vol. 27, Art. 3 the populations: In mallard drakes, one No. 6 shot pellet per bird produces an in- crease in the mortality rate of about 9 per cent (12.6 and 3.4, 15.0 and 4.9 aver- aged ) ; two pellets about 23 per cent (43.6 and 3.4 averaged) ; four pellets about 36 per cent; and six pellets about 50 per cent. Because of the smaller number of ex- periments conducted with hens than with drakes, it is more difficult to appraise mortality from lead poisoning in the hens. However, the available data suggest that, among hens and drakes with identical in- gested shot levels, hens probably suffer twice as great a mortality as drakes in the fall and a small fraction of the mortality of drakes in late winter and spring. PREVENTING LEAD POISONING When Green & Dowdell (1936) re- ported on the apparent feasibility of a lead-magnesium alloy shot for the preven- tion of lead poisoning in waterfowl, con- servationists anticipated the eventual de- velopment of this or some other shot that would prove to be nontoxic to waterfowl and acceptable to hunters. However, no shot (with the possible exception of iron shot) has been developed which meets the requirements of both nontoxicity to water- fowl and present shooting standards. A study of shot alloys by Jordan & Bellrose (1950) at the Havana labora- tory of the Illinois Natural History Sur- vey did not substantiate the findings of Green & Dowdell (1936:487-8) that lead-magnesium shot, upon its disintegra- tion in the gizzard of a duck, fig. 8, did not cause lead poisoning. On the con- trary, Jordan & Bellrose (1950:166~7) found that lead-magnesium shot, in spite of its disintegration in the gizzard, was as toxic as commercial lead shot. Two other types of lead alloy shot tested by Jordan & Bellrose (1950: 165-7), lead-tin-phosphorus shot and lead-calcium shot, were not less toxic than commercial shot. A proposal to coat commercial shot pel- lets with a nylon plastic was investigated. Theoretically, at Jeast, pellets so coated would have a good opportunity to pass out of the gizzard before the plastic was abraded away and the lead exposed. It May, 1959 BELLrosE: LEAD PoIsoNING IN WATERFOWL 201. Z Fig. 8—The breakup of three lead alloy shot pellets containing magnesium (2 per cent) in the gizzard of a mallard; 4, 1 hour after ingestion; B, 24 hours after ingestion; C, 96 hours after ingestion; D, 144 hours after ingestion. As shown in D, the gizzard has failed to expel a large proportion of the lead particles. Despite its disintegration in the gizzard, the lead alloy shot containing magnesium was as toxic as commercial lead shot. 278 Table 29.—Relative effectiveness of iron ILtinois NATURAL History SURVEY BULLETIN Vol. 27, Art. 3 shot and commercial lead shot as measured by the per cent of sample (game-farm mallards) bagged with No. 4 and No. 6 shot fired from 12-gauge full-choke gun at each of four ranges, 1950 and 1951. Iron SHOT Leap SHOT R No. 4 No. 6 No. 4 No. 6 ANGE IN YARDS Number Per Number Per Number Per Number Per in Cent in Cent in Cent in Cent Sample | Bagged | Sample | Bagged | Sample | Bagged | Sample | Bagged SSP At ae ere 6 100 6 100 10 100 10 100 AOE cers 20 90 20 90 20 100 20 90 SOR. 20 75 20 55 24 88 28 79 60.. 20 45 8 12 20 70 18 22 was found, through administering pellets of nylon plastic to mallards at the Havana laboratory, that this material was very re- sistant to abrasion. However, efforts to coat shot pellets with nylon plastic were unsuccessful. Metallurgists of the Win- chester-Western Cartridge Division of the Olin Mathieson Chemical Corpora- tion were unable to coat commercial lead shot with nylon plastic because the spread between the melting point of lead and the congealing point of the nylon plastic was too small. Several metals generally regarded as being nontoxic to waterfowl were consid- ered as substitutes for lead. Domestic availability, price, physical and mechani- cal properties, and corrosion resistance were the judgment criteria. Of all the metals considered, iron was the only one available in sufficient quantity and low enough in price to warrant further inves- tigation. From the standpoint of prop- erties alone (excluding availability and price), there are metals that would make as good or even better shot pellets. Gold is an extreme example. It is soft, non- toxic, noncorrosive, and heavier than lead. However, its price and lack of availability immediately rule it out. Pellets made from an iron alloy were tested at the Illinois Natural History Survey Havana laboratory for toxicity to waterfowl. Penned wild mallards were dosed, each with 10 No. 6 iron pellets. The ducks showed no ill effects as a result of the ingestion of iron. The Winchester-Western Cartridge Division expended considerable time and effort in the development of a satisfactory shot of iron alloy. Early difficulties in making true spheres, excessive abrasion Table 30.—Relative effectiveness of iron shot and commercial lead shot as measured by the average number of No. 4 and No. 6 pellets that hit the trunks of game-farm mallards, and the per cent of pellets hitting the trunks that penetrated to the trunk cavities, at each of four ranges, 1950 and 1951. The shot was fired from a 12-gauge full-choke gun. Iron SHOT Leap SHOT No. 4 No. 6 No. 4 No. 6 ee Per Cent Per Cent Per Cent Per Cent Yaris Average | of Trunk | Average | of Trunk | Average | of Trunk | Average | of Trunk Number of|Hits Pene- |Number of} Hits Pene- |Number of| Hits Pene-|Number of} Hits Pene- Trunk | trating to| Trunk trating to} Trunk trating to| Trunk | trating to Hits Trunk Hits Trunk Hits Trunk Hits Trunk Cavities Cavities Cavities Cavities 35). 8 3 60 16.2 43 6.6 65 11.6 47 40.. 6.8 39 11.8 27 Sie7, 68 8.8 41 50.. 39 21 4.9 17 322 59 Sy) 33 60. . 24 17 1.9 o ponds 48 3.4 18 May, 1959 of gun barrels, and range limitations were for the most part overcome. A special shooting process (Patent No. 2,544,678) was developed. By repeated annealing in furnaces with controlled atmospheres, the iron alloy was substantially reduced in hardness. Many thousands of shot shells fired with iron shot loads showed that soft iron had little, if any, adverse effect on modern gun barrels and adjustable chokes. One of the principal disadvantages of using iron shot for shot shell loads is that its lower density reduces its effectiveness at maximum ranges. In 1950 and 1951, the relative killing power of iron shot and of lead shot was investigated by shooting game-farm mallards under controlled con- ditions (Bellrose 1953:353-5). No. 4 and No. 6 shot were used at ranges of 35, 40, 50, and 60 yards, table 29. Iron shot and lead shot fired from a 12-gauge, full-choke gun showed no differ- ence in killing power at 35 yards, but iron shot declined in relative effectiveness as the ranges increased. At ranges of 35 and 40 yards, the num- ber of pellets hitting the trunks of ducks averaged higher for iron shot than for lead shot, table 30. For comparable ranges and shot sizes, the percentage of pellets hitting the trunks that penetrated to the body cavities was greater for lead shot. The greater number of hits registered on game-farm ducks by iron shot than by lead shot at the short ranges can be ex- plained by the larger load of iron pellets in each shot shell. Because of the lower density of iron, more iron pellets than lead pellets of the same size can he loaded in a shot shell having the same powder charge. A standard 12-gauge duck load contains about 169 No. 4 lead pellets; such a load would contain about 250 iron pellets. Because the impact potential of shot at long range increases with increases in size of shot, some compensation can be made for the relative decline in killing power of iron shot at long range by using iron shot one size larger than that custo- marily used in lead shot, that is, No. 4 instead of No. 5 in a given situation. There are no insurmountable obstacles to the use of iron shot for waterfowl hunt- ing. The conclusion which Winchester- Western drew from extensive research BELLROSE: LEAD POISONING IN WATERFOWL 279 was that an iron shot acceptable for most shot shell requirements could be produced. However, the required manufacturing in- vestment would be large, and this factor, coupled with uncertainty concerning cus- tomer acceptance, convinced W inchester- Western that manufacture of iron shot was not feasible unless drastic action was needed to save waterfowl from serious lead poisoning losses. If drastic action should at any time be necessary, the U. S. Fish and Wildlife Service could require waterfowl hunters to shoot only shells containing iron shot; shells with such a load could be so marked that inspection by conservation officers would insure compliance with regulations. DISCUSSION The incidence of ingested lead shot in the segment of a duck population har- vested by waterfowlers is not representa- tive of the entire population nor the en- tire year. It is representative of only a part of the population (the segment har- vested) and a short period of time (the time of sampling). The percentage of ducks that have in- gested shot at some time during the year, or during the period in which most inges- tion of shot occurs, may be calculated through application of correction factors that take into account (1) the fact that ducks carrying lead are more vulnerable to hunting than are lead-free ducks and (2) the fact that most ducks ingesting lead either void the lead or die of poisoning within about 4+ weeks. As shown by experiments in which wild mallards were trapped, banded, and released, some dosed with lead and others not dosed, the birds dosed with one No. 6 shot pellet each were about 1.5 times (1.19-1.84, table 20) as vulnerable to hunting as were the controls; those dosed with two pellets each were 1.89 times as vulnerable as the controls; and_ those dosed with four pellets each were 2.12 times as vulnerable. The incidence of lead in an entire population at any one time is therefore less than the incidence of lead in the segment of the population taken by hunters; for the populations dis- cussed in this paper the incidence of lead can be calculated by applying 1.5, 1.9, and 280 ItLtinois NaturAL History SurvEY BULLETIN 2.1 as correction factors at the one-, two-, and four-pellet levels. Application of the correction factor de- signed to nullify hunting bias at the one- pellet level indicates that during the hunt- ing season an average of 2.96 per cent of the mallards of North America are car- rying one ingested lead pellet each, table 31. The application of correction factors at other shot levels is shown in table 31. The correction factors for three-, five-, and six-plus-pellet levels were derived through interpolation or extrapolation. Daily during the fall and winter months, some ducks in the North Ameri- can population are ingesting shot pellets, some are voiding them, some are dying from their effects, and some are recover- ing. Unpublished Natural History Survey reports of laboratory studies by James S. Jordan show that penned wild mallards that have ingested one or more No. 6 shot pellets each may eliminate the pellets as early as the first week after ingestion or they may retain them as long as several weeks, until the pellets have become thin wafers 0.05 inch or less in diameter. The appearance of lead pellets that have spent various periods of time in the gizzards of ducks is shown in fig. 9. Vol. 27, Art. 3 The penned wild mallards that were dosed by Jordan with one No. 6 shot pel- let each and that showed few or no indi- cations of lead poisoning had eliminated the pellets by the thirty-first day. The average period of lead retention by the ducks in this category was 18 days. Mal- lards that were dosed with two or with four pellets each and that showed no sig- nificant manifestation of lead poisoning had eliminated the pellets about as rap- idly as those dosed with one pellet each. The penned mallards that were dosed with one No. 6 shot pellet each and that showed moderate to severe effects of lead poisoning had eliminated no pellets in the first week; at the end of 4 weeks, only 27 per cent of these ducks had voided all the pellets with which they had been dosed. Twenty-one per cent of 119 penned mallards that had eliminated all shot pel- lets they had been given (one to four pellets each) died from lead poisoning. A study of the history of these ducks led to the conclusion that a large proportion of the ducks that retain lead shot for 3 or more weeks die from its effects. As previously discussed, most mallards in the wild that die from lead poiconinz perish in the second or third week after they have ingested lead. Most mallards Table 31.—Estimated percentages of North American mallard population lost as a result of lead poisoning. The figures for the various shot levels have been corrected for hunting bias and population turnover. the gizzard of a duck.) (By shot level is meant the number of ingested shot pellets found in SHOT SHOT Per Cent HunrTING InciDENCE | INcIDENCE | MortTAtity OF SHot LEVEL SHOT Bias CorreEcTED | CorRECTED RATE Popu- Inci- CorreEc- FOR FOR (PERCENT)}{t| LATION DENCE TION HuntTinc Turn- Lost§ Facrort Brast OVER** [hoe 4.44 15 2.96 17.76 9 1.69 Dison. 1.14 1.9 0.60 3.60 23 0.83 Bye 0.47 2.08§ 0.24 1.44 308§ 0.43 4., 0.18 Dal 0.09 0.54 36 0.19 Ser 0.14 2.28§ 0.06 0.36 4388 0.15 Oat A hes wee 0.05 2.38§ 0:02 2 aor 508§ 0.06 Galen ce dea ae 0.38 2.48§ 0.16 0.96 7588 0.72 Total en 6.80 4.13 24.78 3.98 *From table 11. + From table 20, nearest 0.1. {Derived as explained on pages 279 and 280 (at one-pellet level: **Turnover correction factor 6, derived as explained on page 281. ++Derived as explained on page 276. These fgures are for mallard drakes of the Mississippi Flyway, but they are applicable to the continental mallard population. 8Derived by multiplying mortality rate (per cent) by shot incidence corrected for turnover. 8§Derived by interpolation or extrapolation from available data. 4.44 & 1.5 = 2.96). May, 1959 that ingest lead have either died or re- covered within 4+ weeks. Observations in the field and in the laboratory indicate that a mallard that survives ingestion of lead will have elim- inated the lead 18 days, on the average, after ingestion; a mallard that dies with lead still in its gizzard will die 21 days, on the average, after ingestion. Because of these observations, 20 days have been BELLROSE: LEAD PoIsonNING IN WATERFOWL 281 populations ingest lead shot. Malysheff (1951), after making chemical analyses for lead in the bones and livers of water- fowl taken in the Lower Fraser Valley of British Columbia, reported that 52.1 per cent of the 79 mallards he examined had at one time or another in their lives in- gested lead; at the time of examination only about 16 per cent of the mallards had lead in their gizzards and about 36 Fig. 9—The appearance of No. 6 lead shot pellets that spent various periods of time in the gizzards of ducks. chosen as the average period of turnover of leaded mallards in the wild. As indicated by the presence of lead in duck gizzards collected from hunters and by lead poisoning die-offs, the lead poison- ing “season”? (the period of greatest ex- posure to lead deposited in feeding areas from the guns of hunters) is a 120-day period that begins with November and ends with February. If, as believed, mal- lard gizzards collected at any one time are representative of only a 20-day turn- over period, the number of mallards in- gesting lead in the 120-day lead poison- ing “season” is six times the average of the numbers obtained from samples taken in the “season.” ‘Then the factor to be used in correcting for turnover is 6. This correction factor applied to inci- dence figures corrected for hunting bias indicates that approximately one-fourth of the wild mallards of North America in any one year ingest lead shot, table 31. There is evidence that a much larger proportion than one-fourth of some duck per cent had survived previous lead inges- tion. Malysheff found that 38.2 per cent of 35 pintails showed evidence of lead; 22.9 per cent had lead in their gizzards at the time of examination, and approxi- mately 15 per cent had survived previous lead ingestion. Mortality rates for Mississippi Flyway mallards dosed with lead shot are pre- sented in table 31; the figures have been adjusted for survival differences between adults and juveniles, as discussed on page 276. Figures for dosages of three, five, six, and six-plus pellets have been derived by interpolation or extrapolation. If the lead poisoning mortality rates for mallards in other parts of North America are approximately the same as in the Mississippi Flyway, then for the entire North American mallard popula- tion the annual loss due to lead poisoning can be calculated, table 31. The figure 1.60 derived for the per cent of the mal- lard population lost as a result of inges- tion of one shot pellet per duck has greater 282 reliability than the other figures, as it is based on a greater number of field data. The calculations on which the figures in table 31 are based have many shortcom- ings. However, the figure 3.98 arrived at as the percentage of the mallard popu- lation lost as a result of ingestion of lead shot is at least a ‘“‘calculated estimate.” The figures in table 31 need qualifica- tion and interpretation. They do not take into account the number of mallards car- rying lead that are harvested by hunters and so are not wasted. Because ducks carrying lead are more vulnerable to hunting than are ducks that are free of lead, table 20, a considerable proportion of the mallards classified as lost in table 31 are bagged by hunters. The results of twice-weekly surveys of public shooting grounds in central Illinois during recent hunting seasons indicate that the waste, or unharvested loss, due to lead poisoning is about one-fourth less than the 3.98 per cent calculated as the total loss, or ap- proximately 3 per cent. The estimated 3 per cent waste due to lead poisoning represents day-to-day, non- catastrophic losses and does not include such spectacular losses as those associated with die-offs, in which large proportions of localized populations fall victim to lead poisoning. On the basis of data in table 1, it is estimated that, for mallards of the Mississippi Flyway, to the 3 per cent waste mentioned above should be added 1 per cent to cover the die-off losses, a total of 4 per cent. For mallards of other flyways, the die-off losses are markedly less, table 1. Mallards have made up the bulk of the ducks found in important lead poisoning die-offs in the United States in recent years, table 1. This fact is construed to mean that the mallard is more susceptible to lead poisoning than other species of waterfowl. Most available evidence points to the pintail as the species second to the mallard in susceptibility to lead poisoning, table 1. Malysheff (1951) found the pintail even more susceptible than the mallard in small samples taken in British Columbia. Although, as table 11 indicates, in North America as a whole a greater percentage of pintails than of mallards ingested shot, the influence of the more beneficial diet ItLinors NarurAL History Survey BULLETIN Vol. 27, Art. 3 of the pintail is evinced by the rela- tively lower losses among ducks of this species on areas where both pintail and mallard have been involved in important lead poisoning die-offs, table 1. The extremely low shot _ incidence found in the blue-winged teal, green- winged teal, shoveler, and wood duck precludes lead poisoning as a cause of ap- preciable losses in these species. In addi- tion to having a low rate of shot inges- tion, the baldpate and the gadwall feed largely upon leafy aquatic vegetation, food highly beneficial in alleviating the effects of ingested lead; mortality from lead poi- soning is considered to be almost negli- gible in these species. Noticeable lead poisoning die-offs are extremely rare in the redhead, ring-necked duck, canvasback, and lesser scaup, table 1, even though these species have the high- est incidence of ingested shot recorded among waterfowl, table 11. It must be concluded, therefore, that lead poisoning is not an important mortality factor in ducks of the genus Aythya. This fact seems attributable to their beneficial diets. In spite of a low rate of shot ingestion by Canada, blue, and snow geese, table 11, these species have become victims of lead poisoning die-offs on a surprisingly large number of occasions, table 1, but, in each case, the per cent of the population lost has been low. Inasmuch as these geese feed primarily on corn in the areas where the die-offs have occurred, diet appears as an important factor contributing to their mortality. As mentioned above, approximately 4 per cent of the mallard population of the Mississippi Flyway is wasted annually as a result of lead poisoning. The annual mallard waste in other flyways is esti- mated to be between 3 and 4 per cent. The annual waste due to lead poisoning among all species of waterfowl in all North American flyways is estimated to be between 2 and 3 per cent of the popu- lation. Several students of waterfowl have feared that in addition to direct losses due to lead poisoning there are possible indi- rect losses, such as lead-induced sterility. Wetmore (1919:11) and Shillinger & Cottam (1937:400) are among the au- thors who have voiced concern over possi- May, 1959 ble sterility. his concern has been fos- tered by evidence that lead reduced the virility of domestic poultry and acted as an abortifacient in mammals. In two laboratory studies which have been made on the effect of ingested lead on sterility in waterfowl, the conclusion was reached that the lead had little per- ceptible effect upon reproduction. Of the first study, with game-farm mallards, Cheatum & Benson (1945:29) stated that: “These few data indicate that among the mallard drakes used, those which re- covered from lead poisoning did not ex- hibit a significant loss of fertility.’ From the second study, in 1948 and 1949, in which both drake and hen game-farm mal- lards were used, Elder (1954:322) con- cluded that: “Leaded birds received 18 shot while on a grain diet, and the result- ing toxemia was very severe. However, normal birds did not exceed leaded birds in fertility, embryonic success, or hatch- ability. But in both years the normal hens surpassed leaded hens in fecundity for the season.” Rarely do waterfowl in the wild ingest as many as 18 shot pellets per duck, and seldom do waterfowl in the wild recover from toxemia as severe as that exhibited by ducks in the 1949 experiments by Elder. At the present time, lead poisoning losses in waterfowl do not appear to be of sufficient magnitude to warrant such drastic regulations as, for example, prohi- bition of the use of lead shot in water- fowl hunting. Should lead poisoning be- come a serious menace to waterfowl pop- ulations, iron shot provides a_ possible means of overcoming it. Although lead poisoning apparently does not at the present time cause mor- tality of such magnitude as to endanger the North American waterfowl popula- tion, it nevertheless poses an important problem for the future. In the past, the incidence of lead poisoning has increased as numbers of waterfowl hunters have in- creased. Because further increases in the numbers of these hunters are expected, the search for the best possible solution to the lead poisoning problem should be con- tinued. From a compassionate as well as a man- agement viewpoint, lead poisoning is a BELLROSE: LEAD PoIsoNING IN WATERFOWL 283 problem that should concern every sports- man. Birds that die from lead poisoning suffer for 2 or 3 weeks preceding death. SUMMARY 1. The mortality resulting from lead poisoning in wild waterfowl has been a cause of concern to conservationists for many years. 2. A publicized die-off of ducks from lead poisoning near Grafton, Illinois, in January, 1948, brought the problem to the attention of officials of the Western Cartridge Company (now Winchester- Western Cartridge Division of Olin Mathieson Chemical Corporation) and the Illinois Natural History Survey. This resulted in a joint research project on lead poisoning in waterfowl; research was conducted largely at the field laboratory of the Survey on the Chautauqua Na- tional Wildlife Refuge, Havana. 3. The objects of the research project were threefold: (1) evaluation of losses from lead poisoning in wild waterfowl, (2) investigation of lead alloys and other materials for possible use as nontoxic shot, and (3) determination of the physiologi- cal effects of lead poisoning on waterfowl. This paper is concerned primarily with an evaluation of the losses from lead poison- ing. 4+. The approach toward evaluating the importance of lead poisoning involved appraisal of (1) the incidence and mag- nitude of waterfowl die-offs resulting from lead poisoning, (2) the incidence of ingested lead shot among waterfowl populations in fall and early winter, and (3) the extent of waterfowl losses result- ing from the ingestion of various quanti- ties of lead shot. 5. The history of lead poisoning in North American waterfowl dates back to the latter half of the nineteenth century. Losses in the nineteenth century or early twentieth century were reported from Stephenson Lake and Lake Surprise, Texas; Currituck Sound, North Caro- lina; Puget Sound, Washington; Back Bay, Virginia; and Hovey Lake, Indiana. 6. A survey conducted among state and federal conservation agents and agen- cies indicates that in recent years the waterfowl losses from lead poisoning have 284 Ittino1s NaturRAL History SurvEY BULLETIN been largest in the Mississippi Flyway and have been followed in order by losses in the Pacific, Central, and Atlantic fly- ways. 7. In recent years, certain areas in the United States have been the scenes of several sizable die-offs of waterfowl af- fected by lead poisoning. Among these areas are Catahoula Lake, Louisiana; Claypool Reservoir, Arkansas; Lake Chautauqua National Wildlife Refuge, Illinois; and Squaw Creek National Wildlife Refuge, Missouri. 8. Most of the notable waterfowl die- offs from lead poisoning have occurred in late fall and early winter months, after the close of the hunting seasons. Few losses of ducks have been noted in the spring, but losses of whistling swans and of Canada, blue, and snow geese have been reported at that time. There are no recent records of waterfowl succumbing from lead poisoning during the summer months. 9. The mallard has been the principal species involved in sizable lead poisoning die-offs across the nation. The pintail has predominated in losses recorded in the Pacific Flyway. Where both species oc- cur together in the Mississippi Flyway, losses in the mallard have been relatively higher. 10. In the Mississippi Flyway, 1938— 1955, 10.4 per cent of the mallard drakes and 13.0 per cent of the mallard hens picked up in die-offs carried no ingested shot. In experiments with penned mal- lards dosed with one to four No. 6 shot pellets each, 21 per cent voided shot be- fore death. ‘These figures suggest that birds in the wild that succeed in voiding shot are more likely to survive than are penned birds that void shot. 11. Data from four widely separated areas in which die-offs of mallards oc- curred indicate that differences between the areas in the numbers of ingested shot pellets per drake resulted mainly from dif- ferences in availability of shot and in diet of ducks in the die-off areas. 12. The availability of lead shot pellets to waterfowl on a particular body of water is determined by (1) the shooting intensity, or amount of shot on the bot- tom, (2) the firmness of the bottom ma- terial, (3) the size of the shot pellets in- Vol. 27, Art. 3 volved, (4) the depth of water above the bottom, and (5) ice cover. 13. The extent to which various spe- cies of waterfowl are exposed to shot pel- lets on the bottoms of marshes and lakes is influenced by the feeding habits of the birds and by the kinds of food ayvail- able, as well as by the numbers of shot pellets available. 14. The incidence of ingested shot pel- lets in migrating waterfowl populations was determined by (1) fluoroscopic ex- amination of live-trapped ducks, (2) com- pilation of data obtained from investi- gators who had examined waterfowl giz- zards for food content, and (3) fluoro- scopic and direct examination of gizzards, numbering many thousands, obtained from ducks in hunters’ bags. 15. Fluoroscopy of trapped ducks caught at baited traps on a heavily shot- over area revealed that the birds had in- gested abnormally large numbers of shot pellets. Among three species, blue-winged teal, wood duck, and pintail, feeding to- gether, there appeared to be a relation between the percentage of ducks ingest- ing shot pellets and the size of individuals. The species with the largest individuals had the highest percentage of individuals with ingested lead. In two of the species, an appreciably greater percentage of juve- niles than of adults carried ingested lead. 16. Fluoroscopy by wildlife techni- cians on waterfowl breeding grounds dur- ing the summer months revealed a low incidence of ingested. shot among ducks in Utah and Saskatchewan, but a high incidence among those at the Delta Marsh, Manitoba, which is one of the most heavily shot-over areas in Canada. 17. Examination of 36,145 gizzards of waterfowl bagged by hunters in North America revealed many differences among species in incidence of ingested lead. Less than 1 per cent of the Canada geese and less than 3 per cent of the blues and snows had lead in their gizzards. Among the ducks, the percentages carrying ingested lead were as follows: less than 2 per cent of the buffleheads, green-winged teals, mergansers, wood ducks, shovelers, and gadwalls; between 2 and 5 per cent of the blue-winged teals, baldpates, and common goldeneyes; between 5 and 10 per cent of the ruddy ducks, mallards, May, 1959 black ducks, and pintails; more than 10 per cent of the canvasbacks, lesser scaups, redheads, and ring-necked ducks. 18. A study of the feeding habits of the various species of ducks in relation to shot incidence indicated that grit prefer- ences do not influence shot ingestion. 19. The incidence of ingested lead shot was lowest among waterfowl of the Central Flyway, higher among those of the Atlantic, slightly higher still among those of the Pacific, and highest among those of the Mississippi Flyway. State and local variations in shot incidence within each flyway were numerous. The incidence of ingested lead was more than twice as high among ducks taken along the Illinois River as among those taken along the Mississippi. 20. Examination of live and hunter- killed ducks indicated that much of the lead ingested by waterfowl had been fired from the guns of hunters in the season of ingestion. Apparently, much of the shot fired during a hunting season eventually penetrated so deep into lake and marsh bottoms that by the following summer it was out of the reach of waterfowl. 21. Increases in the percentage of wa- terfowl ingesting lead have paralleled in- creases in the number of waterfowl hunt- ers. Because there is expectation that the number of duck hunters will continue to increase, it can be anticipated that lead poisoning will become more _ prevalent among waterfowl than it is at present. 22. The magnitude of the shot level (number of pellets in a gizzard) has an important bearing on the rate of mortality of waterfowl. Among 2,184 gizzards con- taining lead shot, 64.7 per cent contained only one pellet each, 14.9 per cent con- tained two pellets each, and only 7.4 per cent more than six pellets each. 23. A field experiment showed that ducks afflicted with lead poisoning dur- ing the hunting season are more likely to be bagged than are healthy birds. Wild mallards that were dosed with one No. 6 shot pellet each and released were 1.5 times as vulnerable to hunting as were undosed controls; those dosed with two shot pellets each were 1.9 times as vul- nerable; and those dosed with four shot pellets each were 2.1 times as vulnera- ble. BELLROSE: LEAD POISONING IN WATERFOWL 285 24. Among the dosed wild mallards, the ingestion of lead shot pellets did not appear to affect behavior until after the first 5 days. Among birds dosed with one shot pellet each, and that did not die of lead poisoning, the period of affliction ap- peared to persist for about 15 days; among those dosed with two to four shot pellets each, the period was longer. 25. The weakness and fatigue appar- ent in dosed wild mallards that suffered from lead poisoning reduced the ability of the ducks to migrate. The larger the number of ingested shot pellets per bird, the greater was the reduction in move- ment. Band recoveries from a group of mallards dosed with four pellets each showed that less than 5 per cent of the birds migrated farther than 50 miles from the banding station at which they were dosed. 26. Among the dosed wild mallards in 1950 and 1951, at each dosage level the mortality rate from lead poisoning was higher for adult drakes than for juvenile drakes. During the fall months, mortality was higher among hens than among drakes, but by late winter the situation was reversed. Differences in mortality rates among mallards of different ages and sexes were attributed primarily to differ- ences in the quality and quantity of food consumed. 27. In a population of wild mallard drakes, a population made up equally of adults and juveniles, one No. 6 pellet per bird is estimated to cause an increase in mortality rate of about 9 per cent, two pellets per bird an increase of about 23 per cent, four pellets per bird an increase of about 36 per cent, and six pellets per bird an increase of about 50 per cent. 28. An effort to find a lead alloy shot pellet that was nontoxic to waterfowl was unsuccessful. However, iron shot was found to be nontoxic. Most of the diff- culties us: manufacturing iron shot pellets were overcome by technicians of the Win- chester-Western Cartridge Division of the Olin Mathieson Chemical Corpora- tion. At present the principal disadvan- tage in using iron shot pellets for water- fowl hunting is that they are less effec- tive at maximum ranges than are lead pellets. 29. In determining the importance of 286 lead poisoning in a waterfowl! population, it is necessary to eliminate the hunting bias of samples and to ascertain the period of turnover of migrating mallards that are carrying lead in their gizzards. 30. Incidence figures corrected for hunting bias and turnover suggest that approximately one-fourth of the wild mal- lards of North America in any year in- gest lead shot. 31. It is estimated that, each year, ap- proximately 4+ per cent of the mallards in the Mississippi Flyway die in the wild as a result of lead poisoning and that an ad- ditional 1 per cent of the mallards in the flyway are afflicted with lead poisoning but are bagged by hunters. 32. For all waterfowl species in North America, the annual loss due to lead poi- soning is estimated to be between 2 and 3 per cent of the population. ILLINoIs NATURAL History SuRVEY BULLETIN Vol. 27, Art. 3 33. Two studies made outside of IIli- nois indicate that lead poisoning in water- fowl does not seriously curtail the repro- ductive capacity of ducks that recover from the malady. 34. At the present time, lead poison- ing losses do not appear to be of sufficient magnitude to warrant such drastic regu- lations as, for example, prohibition of the use of lead shot in waterfowl hunting. Should lead poisoning become a more se- rious menace to waterfowl populations, iron shot provides a possible means of overcoming it. Because of the increasing numbers of waterfowl hunters and the increasing incidence of lead poisoning, as well as because of the suffering that re- sults among waterfowl seriously afflicted with the malady, the search for the best possible solution to the lead poisoning problem should be continued. LITERAT ORE -CATED Ayars, James Sterling 1947. Lead on the loose. Sports Afield 118(6) :24—5, 92-4. Bellrose, Frank C. 1947. Ducks and lead. II]. Cons. 12(1) : 10-1. 1951. Effects of ingested lead shot upon waterfowl populations. N. Am. Wildlife Conf. Trans. 16:125-33. 1953. A preliminary evaluation of cripple losses in waterfowl. N. Am. Wildlife Conf. Trans. 18: 337-60. 1955. A comparison of recoveries from reward and standard bands. Jour. Wildlife Mgt. 19(1):71-5. Bellrose, Frank C., and Elizabeth Brown Chase 1950. Population losses in the mallard, black duck, and blue-winged teal. Ill. Nat. Hist. Surv. Biol. Notes 22. 27 pp. Bowles, J. H. 1908. Lead poisoning in ducks. Auk 25(3) : 312-3. Cheatum, E. L., and Dirck Benson 1945. Effects of lead poisoning on reproduction of mallard drakes. Jour. Wildlife Met. 9(1) 26-9. Cottam, Clarence 1939. Food habits of North American diving ducks. U.S. Dept. Ag. Tech. Bul. 643. 140 pp. 1949. Further needs in wildlife research. Jour. Wildlite Mgt. 13(4) : 333-41. Elder, William H. 1950. Measurement of hunting pressure in waterfowl by means of X-ray. N. Am. Wildlife Conf. Trans. 15:490-503. 1954. The effect of lead poisoning on the fertility and fecundity of domestic mallard ducks. Jour. Wildlife Mgt. 18(3) : 315-23. Green, R. G., and R. L. Dowdell 1936. The prevention of lead poisoning in waterfowl by the use of disintegrable lead shot. N. Am. Wildlife Conf. Proc. 1:486-9. Grinnell, George Bird 1894. Lead poisoning. Forest and Stream 42(6) : 117-8. 1901. American duck shooting. Forest and Stream Publishing Company, New York. 627 pp. Hartmeister, Felix A., and Martin J. Hansen 1949. ‘The incidence of lead shot in three important Wisconsin waterfowl areas. Wis. Wild- life Res. Quart. Prog. Reps. 8(3) :18-22. Heuer, Wayne H. 1952. The incidence of lead shot in waterfowl of the Pacific Flyway, with special reference to the Great Salt Lake Basin. Master’s thesis, Utah State Agricultural College, Logan. 49 pp. Hough, E. 1894, Lead-poisoned ducks. Forest and Stream 42(6) : 117. Hunt, George S., and Howard E. Ewing 1953. Industrial pollution and Michigan waterfowl. N. Am. Wildlife Conf. Trans. 18 :360-8. Jones, John C. 1940. Food habits of the American coot with notes on distribution. U. S. Biol. Sury. Wildlife Res. Bul. 2. 52 pp. Jordan, James S., and Frank C. Bellrose 1950. Shot alloys and lead poisoning in waterfowl. N. Am. Wildlife Conf. Trans. 15:155-68. 1951. Lead poisoning in wild waterfowl. Ill. Nat. Hist. Surv. Biol. Notes 26. 27 pp. McAtee, W. L. 1908. ‘Lead poisoning in ducks.’ Auk 25(4) : 472. Malysheff, Andrew 1951. Lead poisoning of ducks in the Lower Fraser Valley of British Columbia: a chemical study. Master’s thesis, University of British Columbia, Vancouver. 90 pp. ' Martin, Alexander C., Herbert S. Zim, and Arnold L. Nelson 1951. American wildlife and plants. McGraw-Hill Book Company, Inc., New York. 500 pp. Martin, Dale N. ; 1957. Quarterly progress report, waterfowl investigation. Ind. Pittman-Robertson Wildlife Res. Rep. 18(2) :112-7. [ 287 | 288 ILLINOIS NATURAL History SuRVEY BULLETIN Vol. 27, Art. 3 Mohler, L. 1945. Lead poisoning of geese near Lincoln. Nebr. Bird Rev. 13(2) : 49-50. Munro, J. A. 1925. Lead poisoning in trumpeter swans. Can. Field Nat. 39(7) : 160-2. Phillips, John C., and Frederick C. Lincoln 1930. American waterfowl. Houghton Miffin Company, Boston and New York. 312 pp. Pirnie, Miles David 1935. Michigan waterfowl management. Michigan Department of Conservation, Lansing. 328 pp. Reid, Vincent H. 1948. Lead shot in Minnesota waterfowl. Jour. Wildlife Mgt. 12(2) : 123-7. Shillinger, J. E., and Clarence C. Cottam 1937. The importance of lead poisoning in waterfowl. N. Am. Wildlife Conf. Trans. 2 398-403. : Stall, J. B., and S. W. Melsted 1951. The silting of Lake Chautauqua. Ill. Water Surv. Rep. Invest. 8. 15 pp. Suter, Max 1948. Temperature and turbidity of some river waters in Illinois. Ill. Water Surv. [Rep. Invest. 1]. 14 pp. Tener, John G. 1948. An investigation of some of the members of the sub-family Anatinae in the Lower Fraser Valley cf British Columbia. Master’s thesis, University of British Columbia, Vancouver. 66 pp. Van Tyne, Josselyn 1929. The greater scaup affected by lead poisoning. Auk 46(1) : 103-4. Wetmore, Alexander 1919. Lead poisoning in waterfowl. U.S. Dept. Ag. Bul. 793. 12 pp. Yancey, Richard K. 1953. Lead poisoning on Catahoula Lake. La. Cons. 5(5) :2-5. \' “9 ay Some Recent Publications of the InLrnois NATuRAL History SURVEY BULLETIN Volume 26, Article 3.—Natural Availability of Oak Wilt Inocula. By E. A. Curl. June, 1955. 48 pp., frontis., 22 figs., bibliog. Volume 26, Article 4.—Efficiency and Selec- tivity of Commercial Fishing Devices Used on the Mississippi River. By William C. Starrett and Paul G. Barnickol. July, 1955. 42 pp., frontis., 17 figs., bibliog. Volume 26, Article 5.—Hill Prairies of Iili- nois. By Robert A. Evers. August, 1955. 80 pp., frontis., 28 figs., bibliog. Volume 26, Article 6.—Fusarium Disease of Gladiolus: Its Causal Agent. By Junius L Forsberg. September, 1955. 57 pp., frontis., 22 figs., bibliog. Volume 27, Article 1—Ecological Life History of the Warmouth. By R. Weldon Larimore. August, 1957. 84 pp., color frontis., 27 figs., bibliog. Volume 27, Article 2—A Century of Biological Research. By Harlow B. Mills, George C. Decker, Herbert H. Ross, J. Cedric Carter, George W. Bennett, Thomas G. Scott, James S. Ayars, Ruth R. Warrick, and Bessie B. East. December, 1958. 150 pp., 2 frontis., illus., bibliog. $1.00. CIRCULAR 32.—Pleasure With Plants. By L. R. Tehon. July, 1958. (Fifth printing, with revisions.) 32 pp., frontis., 8 figs. 42.—Bird Dogs in Sport and Conservation. By Ralph E. Yeatter. December, 1948. 64 pp., frontis., 40 figs. 45.—Housing for Wood Ducks. By Frank C. Bellrose. February, 1955. (Second print- ing, with revisions.) 47 pp., illus., bibliog. 46.—Illinois Trees: Their Diseases. By J. Cedric Carter. August, 1955. 99 pp. frontis., 93 figs. Single copies free to IIli- nois residents; 25 cents to others. 47.—Illinois Trees and Shrubs: Their Insect Enemies. By L. L. English. May, 1958. 92 pp., frontis., 59 figs., index. Single copies free to Illinois residents; 25 cents to others. List of available publications mailed on request. Single copies of ILLinoIs NATURAL History Survey publications for which no price is lis will be furnished free of charge to individuals until the supply becomes low, after which More than one copy of any free publication may be obtain without cost by educational institutions and official organizations within the State of Illi prices to others on quantity orders of these publications will be quoted upon request. nominal charge may be made. Address orders and correspondence to the Chief ItttNois NATURAL History SURVEY Natural Resources Building, Urbana, Illinois Payment in the form of money order or check made out to State Treasurer of Illin Springfield, Illinois, must accompany requests for those publications on which a price is BIOLOGICAL NOTES a 29.—An Inventory of the Fishes of Jordan Creek, Vermilion County, Illinois. By R. Weldon Larimore, Quentin H. Pickering, and Leonard Durham. August, 1952. pp., 25 figs., bibliog. 30.—Sport Fishing at Lake Chautauqua, Havana, Illinois, in 1950 and 1951. William C. Starrett and Perl L. } Jr. August, 1952. 31 pp., 22 figs., biblic 31.—Some Conservation Problems of Great Lakes. By Harlow B. Mills. Oc ber, 1953. (Second printing.) 14 pp., ill bibliog. 33—A New Technique in Control of House Fly. By Willis N. Bruce. Dec ber, 1953. 8 pp., 5 figs. 34.—White-Tailed Deer Populations in | nois. By Lysle R. Pietsch. June, 1954. pp., 17 figs., bibliog. a 35——An Evaluation of the Red Fox. Thomas G. Scott. July, 1955. (See printing.) 16 pp., illus., bibliog. | me 36—A Spectacular Waterfowl gratio on Through Central North America. By Fra C. Bellrose. April, 1957. 24 pp., 9 Hk. a 37.—Continuous Mass Rearing of the Euro- pean Corn Borer in the Laboratory. — Paul Surany. May, 1957. 12 pp., 7 bibliog. 38.—Ectoparasites of the Cottontail Rabbit Lee County, Northern Illinois. By Lewis J. Stannard, Jr., and Lysle R. Pietsch. June, 1958. 20 pp., 14 figs., bibliog. 39.—A Guide to Aging of Pheasant Embr; By Ronald F. Labisky and James F. Ops: 4 pp., illus., bibliog. MANUAL Ms 3.—Fieldbook of Native Hlinois Shrubs. — Leo R. Tehon, December, 1942. 307 4 color pls., 72 figs., glossary, index. 5. 4.—Fieldbook of Illinois Mammals. By Donald F. Hoffmeister and Carl O. Mohr. June, 1957. 233 pp., color frontis., 119 figs. g zlos- sary, bibliog., index. $1.75. ; ILLINOIS NATURAL HISTORY SURVEY Bulle tin Printed by Authority of he 2. the State of Illinois We Ge Food Habits of Migratory Ducks in Illinois HARRY G. ANDERSON ‘TATE OF ILLINOIS ®& Wuuiaom G. Stratton, Governor JEPARTMENT OF REGISTRATION AND EDUCATION ©® Vera M. Binks, Director NATURAL HISTORY SURVEY DIVISION ® Hartow B. Mitts, Chie} a ati! ee ta, NATURAL A 4 ° eee ee + = ~ i. a ] . ’ 1 ¥ BeLINOIS NATURAL HISTORY SURVEY Bulletin = Volume 27, Article 4 cs 2 ig ; Printed by Authority of August, 1959 the State of Illinois Food Habits of Migratory Ducks in Illinois moeiek YG. ANDERSON STATE OF ILLINOIS ® WiiaM G. Stratton, Governor DEPARTMENT OF REGISTRATION AND EDUCATION ©® Vera M. Binks, Director NATURAL HISTORY SURVEY DIVISION ® Hartow B. MiLts, Chief Urbana Illinois STATE OF ILLINOIS Wirtiam G Srrarron, Gevernor DEPARTMENT OF REGISTRATION AND EDUCATION Vera M. Binxe, Director BOARD OF NATURAL RESOURCES AND CONSERVATION Vera M. Binxs, Chairman; A. E. Emerson, Ph.D., Biology; Water H. Newnouse, Ph.D., Geology; Rocern Apams, Ph.D., D.Sc., Chemistry; Ropext H. Anverson, B.S.C.E., Engineering; W. L. Everirr, E.E., Ph.D ., Representing the President of the University of Illinois; Detyre W. Morris, Ph.D.. ? esident of Southern Iilinois University NATURAL HISTORY SURVEY DIVISION, Urbana, Illinois SCIENTIFIC AND TECHNICAL STAFF Hartow B. Mixis, Ph D., Chies Bessie B. East, M.S., Assistant to the Chie Section of Economic Entomology f Georct C. Decker, Ph.D., Principal Scientist and Head J. H. Biccer, M.S., Entomologist L. L. Eneutsu, Ph.D., Entomologist Wirurs N. Bruce, Ph.D., Associate Entomologist Norman Gannon, Ph.D., Associate Entomologist W. H. Lucxmann, Ph.D., Associate Entomologist Ronatp H. Meyer, M.S., Assistant Entomologist Joun D. Pascuxe, Ph.D., Assistant Entomologist Joun P. Kramer, Ph.D., Assistant Entomologist Ropert Snetsincer, M.S., Field Assistant Carnot Morcan, B.S., Laboratory Assistant Eucene M. Bravi, M.S., Research Assistant Ricuarpv B. Dysart, B.S., Technical Assistant Recinatp Roserts, A.B., Technical Assistant James W. Sanrorp, B.S., Technical Assistant Eart Srapecpacuer, B.S., Technical Assistant Sve E. Warkxins, Technical Assistant H. B. 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Scnoreneweiss, Ph.D., Assistant Plant Pathologist Rovenia F. Firz-Gerarp, B.A., Technical Assistant Section of Wildlife Research Tuomas G. Scort, Ph.D., Game Specialist and Head Ratex FE, Yeatrrer, Ph.D., Game Specialist Cart O. Mour, Ph.D., Game Specialist F. C. Betirosz, B.S., Game Specialist H. C. Hanson, Ph.D., Associate Game Specialist Ricuarp R. Graser, Ph.D., Associate Wildlife Specialist Ronatp F, Lasisxy, M.S., Assistant Wildlife Specialist Frances D. Rossins, B.A., Technical Assistant Howarp Crum, Jr., Field Assistant Joun L. Rosesperry, B.S., Technical Assistant Rexrorp D. Lorp, D.Sc., Project Leader* Frepericxk Greevey, Ph.D., Project Leader* Guien C. Sanperson, M.A., Project Leader* Jacx A. Ennis, M.S., Assistant Project Leader* Tuomas R. B. Barr, M.V.Sc., M.R.C.V.S., Research Assistant* Bossie Joe Verts, M.S., Field Mammalogist* Erwin W. Pearson, M.S., Field Mammalogist* Keito P. Daupuin, Assistant Laboratory Attendant* Gary P. Ime, Assistant Laboratory Attendant* Section of Publications and Public Relations James S. Ayvars, B.S., Technical Editor and Head Biancue P. Younc, B.A., Assistant Technical Editor Diana R. Braverman, B.A., Assistant Technical Editor Wirtiam E. Crarx, Assistant Technical Photographer Marcuerite VERLEY, Technical Assistant Technical Library Rutn R. Warrick, B Nett Mires, MS., Librarian S., B.S.L.S., Technical Librarian B.S.L.S., Assistant Technical CONSULTANTS: Herretorocy, Hosartr M. Smirn, Ph.D., Professor of Zoology, University of Illinois; Panasito.ocy, Norman D. Levine, Ph.D., Professor of Veterinary Parasitology and of Veterinary Research, University of Illinois; Wu pure Researcn, Wittarp D. Kuimsrra, Ph.D., Assistant Professor of Zoology and Director of Co-operative Wildlife Research, Southern Illinois University *Employed on co-operative projects with one of several agencies: University of Illinois, Illinois Agricultural Extension Service, Illinois Department of Conservation, United States Army Surgeon General's Office, United States Department of Agriculture, United States Fish and Wildlife Service, United States Public Health Service, and others. This paper is a con’ribution from the Section of Wildlife Research. os <= cal (98485—5M—7-59) CONTENTS IP SEMPEB ERSTE NTIS PO aed irc Oe 8 cas Tike ee han Ski Sh ahh Pa AR RR 0 Pies pe 289 7, EEIRCR FESCUE eeedine SIS i na eget Ane A ee At ee SR Pine, Soe ae 290 EP GS ARCNUUIS gS) S220) 11S 2 aR Oy EU AS 5 292 pe LcaaN aS ice Heat MIN St ene LIES Arua oA eedag woereivenilan'E aph cisvahdl Re Huw nettle his ats ate 293 oT ERED VDA i TRIS Pe SAD Oe ee A A TSP ee 297 DS IIPE CIR EAE cs RUE ante eek: woo ce Rvs chads BAe Eee OEAIEO 301 2 FSGS ATT e759) B31 RSE Rey ee 2 IER Fe a Pera eee er ome rary 303 2 EERE ICER Laon ee IED Uae a se oe PC ee PRC a k= 307 eMTaRCEI GDA eee Neca Pee Ne ER eke Oy ho see ery ee eee 308 SUSVDRUTSILERRY | APR fo SN econ ea sr ge A Pe ER teers ORCA 310 SN MTRTERNSA IRE CS ENN ee a Rs occa ie BUM as eine IS EIS Cv SUPA oa ba cL 312 [ibyele, 1D vvelen a sted hn ol ed cane tae ree ge fee AE Me Rae ern ae SON NN STAR or od 314 | RES Eig: STS ZR gee Mice teal tale en Ie ie Sogn Cr le a ne RR ce ie ACE 315 MR Re ete nies Pee PELE ert Grnidhyst ee ale \ciaew teas nsa in gag os DERI Roe aR be coe S17 CBVERIDS ONG, S Aor TaN RAO Va aE eae | (KOS Se Re RE een er open wen eet 4 320 PMECLILECLCIMESE RT Ne Terre ee ede cst te ee geen SAN uratccdie cot a (ey atta) cuore Sy os RAL Rens Be ncic eac nae 321 EUs LEC RE sean San As pe ad ec ED acer Mara One Jeg 322 aU TATIRTO) METIS VE) iS ts, 8/02. sla oe ya, Ul 4 oa. 9 ein wc are tds wie 0 Sem ae ape aero 323 ES ean ATTEN Tee ce NOY aie oS i acces wand ares RUMEETE ee HERE A eR 323 LS TI as UES, OE Sa ae re en eA I RD oe 323 SERENE MDE PIE rt RED Pa WIC are aie ASSIA Goi dls eee eck 8 Soo oa Ste Sere ie Sats SEM alate pees 323 CLOSETS SB. yy PS Pe es aR RS eae ea A ee CUP ort eee 827 (hE CSS Oe AA She Pane ee ee en Mcrae wd ee 328 IRM NINIENGI TCT ns ce I as odio ox os tio 0. a SIMI SERN Saad Me rea iece I eoreae 329 JOLIN SIS Soe) SMG i a a op en a ange An Pe Opa Prie-on SER SRA er” 330 RU NNRr eR er a iy Be Stes he kG. 5, cletninpar ela ra eowia lew boo ehereee in ERAS aOR 330 trie UR reTMME OECD EU Seeks Ae PAG estonia s Be G Heme ea ena pad sae ye ah enaheuetenoNne te 331 PREC MIC OOLE TM NICE CriGASS ees Seis. coc ine Peirsol cud Mlacebhac ott Qh cL meth ch tens Rede A ener B52 OD. PE TEST SV PN a aR 8 x 2 ea fee i a UA A aye Aen SOL ca Seat 332 AME MITTS MINSTER GUO CEC Were olay AI fa aT Sanat ol wlohe asbws sv < Goat al sae Oa alals: win Ree 335 ukEOnDUSHe se. ee oe BN ne CaS EG SOA SS De ok pad tO ot ret Er tp at te 334 eee SPECIE Ce STITA LEWC ECS ec uae, ico ote as. Hates Se Coinuae a ieveonsios ater olcatvara helt ake i ee aga ‘sa ce ha ake ed ol sak , 7 2. -~ 7 - ~ POMS SS Aerial view of property belonging to a duck hunting club in the Illinois River valley. The buildings are surrounded by water, uncultivated bottomland, and cropland. Material for the duck food study reported here was obtained from this club and many others like it along the Illinois and Mississippi rivers. Food Habits of Migratory Ducks in Illinois * , \WENTY-FIVE years ago the wa- terfowl population of North Amer- ica had dropped to such a low point that management of this resource became an important concern of both state and federal wildlife agencies. As a basis for an effective, long-time program of manage- ment for the waterfowl of the Mississippi Flyway, detailed information about the diet of ducks that migrate through Illinois was considered essential. More than 30 years of drainage, silta- tion, and pollution had materially reduced the extent and quality of the Illinois feed- ing grounds that waterfowl had used for centuries. Fortunately for some species of ducks, in the 1930’s, mechanical corn pick- ers came into widespread use in the state. Mechanical picking left more waste corn in the fields and made it more easily avail- able than did picking by hand. Mallards and black ducks were quick to take advan- tage of the new food supply. Previous to 1938, only a small amount of research had been done on the food habits of ducks using Illinois as a stopover on their migration flights. An analysis of the contents of 185 duck gizzards collected in Illinois had been made by Martin & Uhler (1939:5), and a study of the con- tents of 79 duck gizzards collected from the Starved Rock Pool near Ottawa and the Duck Island area near Banner, IlIli- nois, had been made by Bellrose (1938). The need for more data on the food habits of waterfowl in Illinois resulted in the in- vestigation herein reported. Formally designated as Project 2-R, “Correlation of Food Supplies With Food Uses Among Illinois Game Birds,” the investigation was a unit in the program made possible by the Federal Aid in Wild- life Restoration Act and was approved in May, 1939, by the Bureau of Biological *Federal Aid Project 2-R. Supervision of this project was assigned by the Illinois Department of Conservation to the Illinois Natural History Survey. tLeader, Federal Aid Project 2-R, June 1, 1939-June 30, 1941: now employed by the United States Fish and Wildlife Service. HA RR Y2oG, ADD ERS Ont Survey of the United States Department of Agriculture (now Fish and Wildlife Service of the United States Department of the Interior). The project was off- cially begun on June 1, 1939, and ter- minated on June 30, 1941. Part of the material and information on which the in- vestigation was based was collected in 1938. Some of the data derived from the project have been included in previous pub- lications (Hawkins, Bellrose, & Anderson 1939; Bellrose & Anderson 1940, 1943; Bellrose 1941, 1959). Delay in publica- tion of the final report on the project re- sulted largely from the author’s service in the armed forces during World War II and subsequent employment elsewhere. Supervision of Project 2-R was assigned to the Illinois Natural History Survey by the Illinois Department of Conservation. The project was administered by the late Dr. Theodore H. Frison, representing the Natural History Survey, and Anton J. ‘Tomasek, representing the Department of Conservation. Dr. Lee E. Yeager, Arthur S. Hawkins, and Frank C. Bellrose pro- vided technical supervision; all three were members of the Natural History Survey staff at the time of the investigation. ACKNOWLEDGMENTS The writer of this paper gratefully ac- knowledges the assistance of many per- sons. He extends his thanks to personnel of the United States Bureau of Biological Survey, later the Fish and Wildlife Service, for permitting use of the Patuxent Research Laboratory and for giving in- struction in food habits studies during the early stages of this project, especially Dr. Alec Martin for his many helpful sugges- tions and his encouragement. He expresses his appreciation to many present and for- mer members of the staff of the [lIlinois Natural History Survey, especially Dr. Herbert H. Ross, Dr. Carl O. Mohr, and Dr. B. D. Burks for their aid in identify- ing insects; the late Dr. Leo R. Tehon for [ 289 ] 290 his aid in identifying seeds ; William Mar- quardt, Robert Welk, and William Rob- ertson for their statistical assistance; Dr. Harlow B. Mills and Dr. Thomas G. Scott for their many helpful suggestions ; and Frank C. Bellrose and James S. Ayars for their assistance in the writing and edit- ing of this report. Finally, the author extends his thanks to a great many individual hunters and duck clubs for whole-hearted co-operation in the field investigations and in the pres- ervation of material. STUDY PROCEDURE Two general steps were involved in the study procedure: (1) the collection of duck gizzards from strategic locations along the Illinois River and the Missis- sippi River and (2) the laboratory an- alysis of collected material. The limited duration of this investiga- tion made it desirable to choose collection sites that would yield a large quantity of gizzards within the short time of three hunting seasons and that would provide representative samples of the important duck species using the major river valleys in Illinois, frontispiece. “—wenty-one sites were selected along the Illinois River be- tween Ottawa and Florence, Illinois, and 11 sites were selected along the Mississippi River between Rock Island and Quincy, Illinois, fig. 1. Gizzards were obtained during the hunting seasons of 1938, 1939, and 1940 by Arthur S. Hawkins and Frank C. Bellrose of the Illinois Natural History Survey and the author. Arrangements were made for collecting the gizzards of ducks taken by members of duck hunting clubs, by individual hunters, and others. At most hunting clubs, mem- bers had their ducks dressed as_ they brought the birds in from marshes or lakes, fig. 2; the clubs were a source of large numbers of gizzards. Individual or free- lance hunters often hired local profes- sional duck pickers to clean their kills; these pickers were another source of giz- zards. Co-operators were supplied with jars partially filled with a 10 per cent formal- dehyde solution; each jar bore a printed label denoting a species of duck. Duck pickers were instructed to drop each giz- I_ttinois NarurAL History SurvEY BULLETIN Vol. 27, Art. 4 zard into an appropriate jar. Gizzards were collected from the co-operators once each week and stored until such time as their contents could be analyzed. During the three fall hunting periods of 1938-1940, 4,977 gizzards were col- lected, table 1; 90.52 per cent (4,505) of the gizzards came from locations along the Illinois River and 9.48 per cent (472) ROCK ISLAND FLORENCE Fig. 1—Map showing the areas from which duck gizzards were collected in the autumns of 1938, 1939, and 1940 between Ottawa and Florence on the Illinois River and between Rock Island and Quincy on the Mississippi River. came from collecting sites along the Mis- sissippi River. The sample from the IlIli- nois River valley represented 1.6 per cent of the 1938 kill estimated for that region, 2.2 per cent of the 1939 kill, and 0.5 per cent of the 1940 kill. A breakdown of the number of gizzards obtained from 17 spe- cies of ducks is given in table 1 by year and river system. The species are listed August, 1959 ANDERSO N: Foop Hasirs oF Micratory Ducks 291 Fig. 2.—Picking ducks at a hunting club in the Illinois River valley. Duck gizzards collected from this and similar clubs provided most of the material on which the present study is based. As ducks were dressed, each gizzard was placed in a jar containing a formaldehyde solution and bearing a printed label that denoted the duck species represented. representing 17 species of ducks were collected. Nearly 5,000 gizzards Table 1—Number of waterfowl gizzards collected in Illinois, 1938-1940, at stations along the Illinois and Mississippi rivers. 1938 1939 1940 | ‘ ae Tora pagugee OER ILLINOIS ees ILLINoIs Bees. ILLINoIs Bre aes RIVER RIvER RIvER RIVER RIvER RIVER Common mallard*. 822 38 1,289 42 428 206 2,825 American pintail. . 268 9 467 115 22 881 Lesser scaup...... 73 53 66 eye Pete 28 220 Blue-winged teal. . | oy 6 63 1 1 | 129 Green-winged teal 199 2 164 3 25 393 Baldpate. 87 1 61 4 7 160 Ring-necked duck. 97 7 16 wee ee 120 Gadwall.. | 26 3 59 6 4 98 Canvasback....... | 14 4 9 | ae 28 Shoveler.. 25 2 34 foe 1 62 Ruddy duck. . oH ae 1 4 en 5 Wood duck....... 6 3 4 9 4 26 Walackaduckeet sors | chads nore nk 10 1 11 Redhead. . . 12 2) 14 Common goldeneye 2 1 Br 3 Greater scaup..... 1 1 Wlascuiawe-cencae a |) is sae Ste Rn © OMA ore ee Se 1 soll 1 Woighie 1,688 131 2243 43 574 208 4,977 *An unknown, but probably small, common mallard. Some hunters did not distinguish between these two species. number of gizzards of the black duck may in the black duck category were from birds identified by the author. be included with gizzards of the Gizzards from individuals listed here 292 in descending order of the estimated num- bers of individuals in the fall flight. The procedure in making analyses of the gizzard contents was in accordance with standard practices followed by the United States Bureau of Biological Sur- vey (now United States Fish and Wild- life Service) for food habits studies (Cot- tam 1936:9-10). The contents were sep- arated first into organic and inorganic sub- stances and the volume of each expressed as a percentage of the total volume. The organic foods were then separated into plant and animal foods and the volume of each group expressed as a percentage of the total organic volume. As an example, the contents of a mallard gizzard were 8 cc. (80 per cent) organic material and 2 cc. (20 per cent) inorganic material. Of the total organic foods, 6 cc. (75 per cent) consisted of plant foods and 2 cc. (25 per cent) of animal foods. Inorganic material was found in the gizzards in small to large amounts and Intrnois NaATuRAL History SurvEY BULLETIN Vol. 27, Art. 4 consisted primarily of sand, gravel, and calcareous shell material. Individual par- ticles were classified as to size in milli- meters as well as to type and volume. An effort was made to identify each item in the organic contents, even though it constituted only a trace or a fraction of 1 per cent of the volume, tables 38 and 39. The technical names of most identifiable plant items listed in table 38 were taken from Gray's Manual of Botany (Fernald 1950). The technical names of animal items listed in table 39 were taken from several authorities and depended upon the groups of animals involved. Seeds of some of the duck food plants discussed in this report are shown in fig. 3. FOODS OF VARIOUS SPECIES Data obtained from this study provided important facts about food preferences of each of the species of ducks represented. The proportions of plant and animal foods Fig. 3.—Seeds included in the autumn diet of ducks migrating through Illinois: (top row, left to right) giant bur-reed, pickerelweed, American lotus, buttonbush, longleaf pondweed; (second row, left to right) nodding smartweed, large-seeded smartweed, swamp smartweed, marsh smartweed, chufa; (third row, left to right) Walter’s millet, Japanese millet, wild millet, rice cutgrass, water-hemp; (bottom row, left to right) duck-potato, lophotocarpus, Ameri- can bulrush, soft-stem bulrush, sago pondweed. 293 Ducks ANDERSON August, 1959 _— — wa Wh SLESLEESEL BSS pitce ce a cae eS = eS SSSeen SS 8 8 ae we fu Po Ss ae n Ao oc STN w oO. 380 6 & 3) as) et es Oo 5) SS Oa) wy On ee FG eo AIDS 0 rene eters @ ove oN See po 6 os gi Setila) eee See 6 So) a W = mMawrNOWYH i: c een gel 2"o.5 8 SSIES 745 35 YN 0 pus) 3 e WA ww a) eQmNEesgeF es, f= pie Ue Sb od Saye See io reac a Ee ie) Be Se Se) 4 2 o Cw wv wES) Wet > Seas Sap aoe & ee 5 et SgR eB key 5838 Onion Boo By Sa eB og BO SN og Oey oe eee 2 5 . Ses ~ oe Se oo ODO ar eiacoy CS pat elim at peat RA) ete ia Sais a) OowH 5 VY ee oO & Peo Coe. aoe, wre ; = PES ee oe oy Oe Ne SN UN oe ae FOR ot = t 1 . ‘ 222g a4 By oC. op = S 1S) a aes gl rE = ar arate | = aa) = Sl c5 io Wa Fae ae I GO S's AT e656 & ces *ROsa gH 5 Stee So es a. metic aeh se se Cred ache Heine 1B) Hey lS) aici Oo Nn S| 2c Boo Reese Ss Me = 8 if as) AU ay Ree aS! e Sf S@eseloau & iS) = 0°74 8 Sie aces eS == Dee ire 5 = <= 1S oOo v 79) + = Bye eS n = Ce ae Sy SV) Si re, a! ey Sal site See Satie SC SS woe we Se} EN SEE TAR, eerie Goh Pete aes of row, UNS Ce pa Nn ; mos eS eoU gy s 25,5 <3 os 3 Ge) - yn = 4 set eS) (Sle Geel oh oN) =e ae oe ee mS Nc PO Feo) Cees N a ISAS Nash aers el! Shines Hg te er bate oc ei ace v x CPN eae = ts o 4 (3) Cool ey a8 Oy esy te! ey os Ce ee = on ty — Gis Sy oe) te) Sy >| _ aA Ow WY Ne Se onl = z : 2 WWW 220 22979 nd of animal ma & SS Cnn AAAS SSS Jivdaiva ntages of plan PLANTS SCC w0}) 01 'Eu”[1>w>]9]079ys - SANNA ES Lad. DINVSYO. SSOUD JO LNSD dad a e umns of 1938, 1939, and 1940. Each of the most important ely. 294 Ittinois NaturaL History SurveY BULLETIN Vol. 27, Art. 4 Table 2.—Mallard gizzards collected in Illinois in approximately 2-week periods, 1938-1940. YEAR OcroBeR . 16-31 POSE el cer itsr es 282 1 AES Uae RP Se ae eo 389 112 FD ESR Sneek Si Coat 149 Lota iat ee 20 NoveMBER 1-15 272 325 120 717 NumBer OF GizzARDS NoveMBER 16-30 306 396 258 960 DECEMBER 1-15 107 314 *Fourteen gizzards could not be dated to bimonthly periods; ever, they are included in tables 3 an hence, they are not included in this total. Tora. How- Table 3.—The most important plant foods identified in 2,825 mallard gizzards collected in Illinois, 1938-1940. PLANT PORAL PLAN Ee ee i. oe Ma ahs ole eae eee Zea mays,corn ...... Leersia oryzoides, rice cutgrass. Ceratophyllum demersum, coontail. . Polygonum coccineum, marsh smartweed. . pensylvanicum, large-seeded smartweed........... lapathifolium, nodding smartweed. hydropiperotdes, mild \ water-pepper. . Garin punctatum, dotted smartweed.................-- persicaria, \ady’s thumb.. hydropiper, water-pepper. Sagittatum, arrow-leaved tearthumb.............. scandens, climbing false buckwheat.............. amphibium, Water ladys thutmbersion esr eee Winidlentatend oon uo 9 a co to ee ee Echinochloa orusvalltawild millet. ..: ome. er soe. Soha walteri, Walter’s millet......... Wnudeniihed os. segs Ue Pe Cyperus esculentus, chufa.. erythrorhizos, red-rooted 1 nut-grass. AW Fes inetre Souler, strigosus, nut-grass.. Unidentified. ip Acnida altissima, water-hemp. . Potamogeton nodosus, longleaf pondweed..................... pectinatus, sago ‘ig oaahlc ie Ca Eas Meee eae foliosus, leafy pondweed. . pusillus, small pondweed . perfoliatus, thoroughwort pondweed.. ate eae praelongus, white-stem pondweed. . amplifolius, large-leaved pondweed . BAe er ice Unidentified. . Sagittaria MAAC thy QUICK STAD. ones oe ee ae hake: cuneata, wapato ...... Unidentified .. Triticum aestivum, wheat. . Cephalanthus occ identalis, buttonbush. Sh a Other plants. OccuRRENCE (NuMBER OF Gi1zzarDs) VOLUME (Cusic CenTI- METERS) 13,725.53 6,652.11 1,801.33 1,085.11 583.40 172.68 125259 61.12 40.54 12.59 Per Cent or Toray OrGAnNIc ConTENTS 97.73 ee ae ee ee ee CW _ oon SOSSSSSS Nmyooonwovwo MN ot WwW [anole o} ee NoOOorF nNnwmOON August, 1959 grit and 62.75 per cent (14,044.27 cc.) was organic in substance, tables 3 and 4. In 80 per cent of the mallard gizzards, the organic matter consisted of plant parts ex- clusively. Plant Foods (97.73 Per Cent of Or- ganic Contents).—Plant parts, which formed nearly 98 per cent of the food in the mallard gizzards, appeared in all but ANDERSON: Foop Hasits oF Micratory Ducks 295 some gizzards, leaves and stems of coon- tail, and rootstocks or tubers of rice cut- grass, chufa, and duck-potato constituted the entire plant contents. Listed in table 3 are the most important plant foods found in the mallard gizzards collected for this study. Corn made up al- most half of the total volume of plant foods; the amount of corn in the gizzards (00 -—=== —————— Vee ea al me = au al trae LL bg Verein: reas =) ae ee = au See ee OTHER, PLANTS === > Se uw oO “N {e) on PER CENT OF TOTAL PLANT FOODS i) oO OCT. 16-3! NOV. 1-15 aC Ot LE Tesiictet: 2 Z ee LOO ERS NOV. 16-30 DEC. I-15 Fig. 5—Principal plant foods consumed by mallards in Illinois from mid-October to mid- December, 1938-1940, as determined by volumetric analyses of gizzard contents. represent the averages for the periods indicated. 13 of the gizzards. The plant contents of individual mallard gizzards ranged from a trace to 20 cc. and averaged 4.86 cc. per gizzard. The proportion of the organic contents made up of plant structures ranged from 95.17 per cent in 1938 to 99.28 per cent in 1940. Field observations in the areas from which the gizzards were collected in the 3-year period showed that water levels fluctuated from year to year, thus allowing native food plants to be more easily accessible in some years than in others. Although there was some plant debris that could not be identified (0.02 per cent), 101 species of plants in the mallard gizzards were identified. Most of the ma- terial was in the form of seeds, but, in The curves was proportionally greater late in the sea- son than early, fig. 5. Rice cutgrass, coon- tail, wild millet or barnyard grass, and marsh smartweed comprised more than half of the volume of native wild foods. The volume of emergent and moist-soil plant parts was four times as great as the volume of submergent vegetation. Plant species that individually made up less than 1.0 per cent of the total organic volume had been ingested either in small units by a large number of mallards or in large volumes by a few birds. Some of the plant particles may have been taken inci- dentally along with more desirable foods. Animal Foods (2.27 Per Cent of Or- ganic Contents).—Animal matter was found in mallard gizzards taken in each 296 Intrnors NaturaAL History SurvEY BULLETIN Vol. 27, Art. 4 Table 4.—The most important animal foods identified in 2,825 mallard gizzards collected in Illinois, 1938-1940. ANIMAL TOTAL ANIMAL: Feces: BRYOZOA ‘statoblastse< 2 2s5 sie = MOLLUSCA py ieivier ics snails Stagnicola. . Planorbis.. Helisoma trivolvis.. Carinifex newberryi. Physa.. ui Campeloma. . FT eae es) CODES ey Mostra ee. ieee Ee ne, eee Flumnicola. . Pleurocera. . Unidentified Gastropoda. . PELEcypopaA, mussels Sphaeriidae Pisidium. . : Musculium transversum. Sphaerium.. Unidentified Sphaeriidae. . Unionidae, fresh-water clams. . Rochen at Unidentified Pelecypoda......... Uae ee pene UNIDENTIFIED MOLLUSCA Lf os: aci-s) tists is eee ARTHROPODA CRUSTACEA Ostracoda . Malacostraca Decapoda, Cambarus virilis, crayfish......... Amphipoda, Gammarus... Bee Seen ae tos Ta a5 nee (00717 Rn NS ne ne Sha INSECTA Neuroptera, Corydalis cornuta, hellgrammites. . . Ephemeroptera, Hexagenia nymphs, mayflies. . . Odonata Anisoptera, dragonflies Aeshna.. Ritta long antemsern aired om Gomphus notatus.. Unidentified Anisoptera. . Zygoptera, Coenagrionidae nymphs, damsel- tlies. . JUsS ARBRE Unidentified odonata nymphs. . Bi iis ela Homoptera, Cicadellidae, leafhoppers. eS Nap te Hemiptera Corixidae, Corixa, water boatmen........... Notonectidae, Notonecta, backswimmers.. .. . . Nepidae, Ranatra, waterscorpions........... Belastomatidae, water bugs................. Gerridae nymphs, water striders............. Lygaeidae, Lygaeus, chinch bugs............ Pentatomidae, ‘stink bugsitesceiiy . opie exes Unidentified Hemiptera. Coleoptera Carabidae, ground beetles. . Halipidae.. Dytiscidae, diving beetles. Gyrinidae, whirligig beetles. . Bente Reet Hydrophilidae, water scavenger beetles....... Staphylinidae, rove beetles...............4. Buprestidae, flatheaded wood borers......... OccuRRENCE (NUMBER OF GIzzARDs) nN =) _ AD Pe he NNe a eRe PO ~ eS Oe Bl tin’ Maal > te) NP ~ i) _ ii) ROA Re NOOO VOLUME (Cusic CENTIMETERS) 318 74 0.30 RNOWO=SOmS PNWWOWAN HAND ocooooocoNnNcoeo nN Per Cent oF ToTaL OrGANIC ConrTeENTS 2.27 0.002 August, 1959 ANDERSON: Foop Hasits or Micratory Ducks 297 Table 4.—Continued. OccuRRENCE VOLUME | Per CENT OF ANIMAL (NuMBER OF (Cusic Tora Orcanic GizzarDs) CENTIMETERS) ConrTENTS Elmidae.. 1 t heoe eee Scarabaeidae ,Aphodiusdistinctus, scarab beetles 2 0.06 0.0004 Chrysomelidae, leaf beetles. . DRM wsigieeee 1 0.26 0.002 Curculionidae, snout Bectleen tt en, 15 2.80 0.02 leinidentitied: Coleoptera. 92... asaccees oats a 4 0.50 0.004 Trichoptera, caddisfies Hydroptilidae. . 28 0.77 0.005 Hydropsychidae, Hydrop syche larvae. 5 8.20 0.06 Unidentified Trichoptera cases. 7 3.16 0.02 Lepidoptera Noctuidae, cutworm moths....... 2 0.29 0.002 Unidentified Lepidoptera moths. 1 0.10 0.0007 Diptera Chironomid larvae, midges... 2.0.05. <<<. 05. 72 DON 0.19 WPabanidac Norse TIES. 4. sce oo wna 8 «tien, < 1 0.20 0.001 imidentitied Wiptera to. .06- oe wef sy or wr oes 11 Leis 0.008 Hymenoptera Formicidae, ants. 4 t Tiphiidae, Tiphia, tiphiid wasps. 1 t AeA Cede eee Unidentified Insecta...... 10 S77 0.03 ARACHNIDA.. AAT 13 0.62 0.004 ACARINA, water mites. 19 t eects CHORDATA TPRISVETOS 5G) A cao oct ete ney ie 14 0.22 0.002 PE IUBU Aa EOS ceca ssn t cetele «ous sere, eve sibel é 1 1.00 0.007 NONFOOD EZARAST DLC AV WORMS ee cohen ictet eye \arsks/sisieieletere, + 0: ieee sieve 1 0.20 0.001 FEATHERS. 43 4.90 0.03 UNIDENTIFIED.. 3 0.20 0.001 of the collecting periods of the fall months, the greatest volume from November 16 to freeze-up. Even though animal foods were found in 580 mallard gizzards, they ap- peared to be relatively unimportant in the fall diet. “The animal remains in individ- ual gizzards amounted to only a trace, ex- cept in a few gizzards which held as much as 12 cc. each. An animal group was considered an im- portant source of mallard food if it pro- vided at least 0.1 per cent of the total or- ganic contents. Of the animal foods found in the mallard gizzards, table 4, about two-thirds of the volume consisted of in- sects and approximately one-third of snails and mussels. Inorganic Contents (37.25 Per Cent of Total Contents).—Grit and other in- organic material in individual mallard gizzards varied from a trace to 9.4 cc. and averaged 2.95 cc. per gizzard. Except for calcareous material in one gizzard, the in- organic contents consisted of stones rang- ing in size from minute to 19 mm. (largest dimension) ; however, in most instances, the stones did not exceed + mm. American Pintail Anas acuta In about 80 per cent of the pintail giz- zards collected, table 5, the organic con- tents consisted of plant material exclu- sively. Vegetation was found in 99 per cent of the gizzards. These percentages seem to indicate that the pintail, in [lli- nois at least, utilizes vegetation to a slight- ly greater feores than does the mallard. Of the pintail gizzards collected, 31 came from the Mississippi River area and 850 from the Illinois River valley. A pintail gizzard was assumed to be full if the gross contents amounted to 14.0 cc. or more; the average was 6.2 cc., and the extremes ranged from a trace to 16.5 cc. Approximately 210 gizzards were either less than one-quarter or more than three- quarters full, and only 6 were classified as full. In no collecting period were the pro- portions of full and nearly full gizzards 298 Ittrnois NaturAL History SurvEY BULLETIN Vol. 27, Art. 4 significantly greater than in any other. The gross contents of 881 pintail giz- Fatty tissue was much in evidence around zards amounted to 5,431.91 cc., of which most of the pintail gizzards. 37.52 per cent (2,038.20 cc.) was grit and Table 5.—Pintail gizzards collected in Illinois in approximately 2-week periods, 1938—1940. NumBer OF GIzzARDS YEAR Tora OcToBER NoveEMBER NoveMBER DECEMBER 16-31 1-15 16-30 1-15* 19380" sig foes 135 Tate 71 ia 277 [A Bo pelea wage ri 202 86 92 87 467 [ROP UD ae Makati Bae ees 76 32 29 Pm so, : 137 Olan a, Se 413 189 192 87 881 *No pintail gizzards collected in this period in 1938 and 1940; an early freeze occurred in 1938. Table 6—The most important plant foods identified in 881 American pintail gizzards col- lected in Illinois, 1938-1940. i OccuRRENCE VOLUME Per CENT oF PLANT (NuMBER OF (Cusic Tora. Orcanic GizzArRDs) CENTIMETERS) ConTENTS CEOS BP 4 SAR 4 Sr J At AR Sn le ies a ee RR ed eI Um aa aera NCR rol i 96.99 Echinochloa amano Wud Tet. ork. Se ae hb ae eae 198 436.65 12.88 walteri, Walter’s millet. . eres os MEE cee ue 98 265593 7.83 Leersia oryzoides, rice cutgras 2 RM 0 Tok Ae ai 555.29 16.36 Zea mays, corn. Ses Sata alt ann hs Ot pce Va GE 138 532.92 15.70 Cyperus erythrorhizos, red-rooted pees ecoseesepnteeone ts 183 298.72 8.80 strigosus, nut-grass. . ash SP nee AeA Orta aide 135 131.28 3.87 PICUIPRIAS JEM AEE cle IR SRS NOS Ae 3 83 S570. 1.62 Tigre letter Saar a! sc We aia eee + 8.40 0.25 Polygonum cocctneum, marsh smartweed.. ...... 22.620. 000s 422 126.97 a7 lapathifolium, nodding smartweed............... 257 45.96 135 hydropiperoides, mild water-pepper. Sir Ret he 56 21.10 0.62 pensylvanicum, large-seeded smartweed........... 87 18.55 0.55 punctatum, dotted smartweed..............----. 36 15.24 0.45 Perittania, Naay SithUIMDss Fe eee Pee Paws, 49 5.32 0.16 hydropiper, water-pepper. . SOG NS ne eee 16 2.95 0.09 amphibium, water lady’s phnatictbiinnlite ee dees 0s 3 0.02 0.0006 Unidentified . . eR a ale rns ats 2 0.30 0.009 Ceratophyllum demersum, Goantal to 110 216.25 6:37 Acnida altissima, water-hemp. . Be Sea een aA aoe 198 117.88 3.47 Potamogeton nodosus, longleaf pondweed..................-.. 223 48.01 1.41 pectinatus, sago rode cae eae He eM SaaS rac 107 20.28 0.60 joliosus, leaty pondweeds 22... Sos. 4 ane ok 61 16.79 0.49 “pusillus, sinall pondweegir 2} ieee oe 16 3.04 0.09 Other Potamogeton.. ROSE Src ht cnt, See Le RR 4 t eee ia Eragrostis hy pnoides, teal grass... Barter eae 45 81.30 2.40 Cephalanthus occidentalis, buttonbush. . SEN a ee 154 61.62 1.82 Sagittaria latifolia, cuck-potator: gs ete eee. Fee ee 29 36.56 1.08 PINON TGR oh Sai Oran Net be iM Coma ve ee anes 1 0.01 0.0003 Lemna MeMOF eWSeY ONC WEER hi. tes eke em 34 33.69 0.99 Winidendied 25 6e" Ge lk pate ieee ae Bt 1 1.8 0.05 MRE R NAR yf og. ante sc Bis cae ae Ses ch We 394 133.74 3.94 August, 1959 ANDERSON: Foop Hasits or Micratory Ducks 299 Table 7.—The most important animal foods identified in 881 American pintail gizzards collected in Illinois, 1938-1940. OccuRRENCE VOLUME Per CENT OF ANIMAL (NuMBER OF (Cusic Tora OrGANIC Gizzarps) CENTIMETERS) ConrTeENTS OUT ANE, LONGING CU RAR eee RPO Ae HG fe o.oo eerie | reac cee 102.27 3.01 MRMOZOAstatoblasts. o. 1: saacsds «aga ssowe ae een 15 1.44 0.04 MOLLUSCA GAsTROPODA, snails Planorbis.. Ht 2 t ee Helisoma trivolvis.. ac) «eta ee ees oat 1 0.70 0.02 Gyraulis parvis. 5. reeves e veces 1 0.10 0.003 Physa gyrina.. 1 0.10 0.003 Campeloma.. + 3.70 0.11 Lioplax subglobosus . . 1 0.30 0.009 Amnicola..... l 0.40 0.01 Unidentified Gastropoda. . 22 15.54 0.46 PELEcypopDaA, mussels Sphaeriidae IES MUD 0 Bia e 4 5.08 Onis Musculium transversum. Ee reoiete Gh, Gack 2 2.70 0.08 Sphaerium....... Saya e eer enter 7 6.70 0.20 Unionidae, fresh-water clams. ee 1 1.70 0.05 Unidentified Pelecypoda.. ieatiarer hacia 8 4.30 0.13 UnwentirieD MOLLUSCA........ 00-000 c ee eee. 12 6.07 0.18 ARTHROPODA CRUSTACEA SERA COG AEM nego aera t ety ct 3 eco tease acute) cess 3 0.50 0.01 Malacostraca Amphipoda, Gammarus... .0..-.26200+5.5--% 1 t aS ey ISG POC AMEASEL/WISN Wa Montene.) ne Petes Meee inees 2 0.11 0.003 INSECTA Orthoptera, grasshoppers INADADHORG NALS sos 92 6000 005 SO Sade ee oe De 1 0.20 0.006 Ephemeroptera, mayflies ICIPRATUTE IONS ao coc co eeoe oo Bene Da be de: 9 4.50 0.13 TT BRUSASTS 5G 9) | URES SEINE ae a Se a ea i 0.10 0.003 Odonata Anisoptera, ee AURORS TSAI she Pesede each aeaet teat op tae 3 2.90 0.09 Anisoptera nymphs. . Saath oy Ret eh Bieler oe 1 0.10 0.003 Zygoptera, damselnies COST NAVE OTTTES Ea 1 0.10 0.003 EXERT TVD) Sing g cau co beguen acess 08s 2 0.90 0.03 Wnidentinedt@donatawe nae + tree en ae 2 0.90 0.03 Hemiptera Corixidae, Corixa, water boatmen........... 27 6/3 0.20 Nepidae, Ranatra, waterscorpions........... 1 0.20 0.006 Pelastomatidae, predaceous water bugs..... . 5 2-53 0.07 Miridae, Lygus lineolaris . ee 1 0.02 0.0006 Lygaeidae, Lygaeus kalmii, chinch h bugs. Hele 1 0.03 0.0009 Unidentified Hemiptera. . SO 1 t alae Coleoptera Carabidae, ground beetles CASRD HB NALPSWWALIG Is 6668 ob ye ee oec ase 1 0.04 0.001 WaidentitediCarabidaettcme cs) eens oe 9 t ee Haliplidae.. a: Le es 1 6.10 0.003 Dytiscidae, diving beetles Colymbetes.. ET con ee eat 1 0.20 0.006 Unidentified ‘Dytiscidae... . 41 7.30 0.22 Hydrophilidae larvae, water scavenger beetles 2 0.20 0.006 Staphylinidae, rove beetles ...... ey 1 0.20 0.006 Scarabaeidae, Aphodius distinctus, scarab SESE Re Oe eS alee tren, 1 0.05 0.001 300 Intinois NatrurAL History Survey BULLETIN Vol. 27, Art. 4 Table 7.—Continued. OccuRRENCE VOLUME Per CENT OF ANIMAL (NuMBER OF (Cusic Tora Orcanic GizzaArRDs) CENTIMETERS) ConrTeNTS Chrysomelidae, leaf beetles Diabrotica undecimpunctata howardi....... 1 t 5 ee Lseus: ed 1 0.20 0.006 Unidentified ‘Chrysomelidae. . Tce 1 t SAO ALN Curculionidae, snout beetles........... 2 t Trichoptera Hydroptilidae cases, caddisflies.............. 32 3.42 0.10 Hydropsychidae, Hydropsyche.............. 1 0.30 0.009 Unidentified Trichoptera............ 5 0.25 0.007 Diptera Chironomidae larvae, midges............. 39 18.09 0.53 Unidentified Dipteray en. ee eee 2 0.03 0.0009 Hymenoptera Ichneumonidae, ichneumon flies............. 1 t Be ie a Tiphiidae, Tiphia.. 1 0.10 0.003 Formicidae, ants. NS RON. ree A D 0.10 0.003 Unidentified Hymenoptera... ae ety Nia. 1 0.96 0.03 Unidentified Insecta. . Pry s 1 t BN ease ARACHNIDA Araneae, spiders Argiopoidea. . in data eee cae eee 1 0.03 0.0009 Unidentified Araneae. 1 t kee ee Unidentified Arachnida. . Be SAA Hy 2 3 t én Se Acarina, Hydracarina, Writer unites! MOLLUSCA GAsTRopODA, snails Gyraulus parvus. . Physa. Unidentified Gastropoda. . Untwentirtep Moutusca shells. . ARTHROFODA (GRUISTACEANASC/I1150 cre. ho clots nn tila ati aioe. sie « INSECTA Ephemeroptera, Hexagenia nymphs, mayflies.. . Odonata nymphs, dragonfies Homoptera, Cicadellidae, eu hones Draeculacephala. . ; nes Unidentified Homoptera... Hemiptera Conixanwater boatinenincn. mee ricei cele 1 MEN ELISINUSITE OL GIUSA routine nh treks, » Ae eee 1 t the inorganic material consisted of quartz particles varying in size from minute to 2 mm. (largest dimension) ; the material in- cluded an occasional stone up to 11 mm. Ruddy Duck Oxyura jamaicensis Only five ruddy duck gizzards were col- lected for this study. All were obtained between October 15 and November 15, 1939 and 1940. The gross contents of these gizzards amounted to 16.6 cc., of which 63.86 per cent (10.6 cc.) was grit and 36.14 per cent (6.0 cc.) was organic material. Of the organic food, plant struc- tures amounted to 23.33 per cent and ani- mal matter to 76.67 per cent. Plant Foods (23.33 Per Cent of Or- ganic Contents).—Plant parts appeared in three of the five ruddy duck gizzards; only a trace in two and 1.4 cc. in the other. Four species of plants were represented: coontail made up almost 100 per cent of the bulk; longleaf pondweed, leafy pond- weed, and wild millet appeared as traces. Animal Foods (76.67 Per Cent of Organic Contents).—Animal structures were found in all five ruddy duck giz- zards. The animal contents of individual gizzards ranged from a trace to 1.7 cc. Midge larvae comprised almost 100 per cent of the animal matter; water boatmen and water beetles appeared as traces. Inorganic Contents (63.86 Per Cent of Total Contents).—Gravel made up Vol. 27, Art. 4 id August, 1959 nearly two-thirds of the gross contents of the ruddy duck gizzards. The inorganic contents of individual gizzards ranged from 1.2 to 4.0 cc. and averaged 2.1 cc. Most gravel particles were each smaller than 2 mm. (largest dimension). Common Goldeneye Bucephala clangula Only three goldeneye gizzards were ob- tained for this study, all of them in the period November 14-30, 1938. The total gross contents amounted to 2.6 cc., of which 50.00 per cent (1.3 cc.) was grit and 50.00 per cent (1.3 cc.) was organic material. Longleaf pondweed, which con- stituted 15.38 per cent of the organic con- tents, was the only important plant species represented, while mayfly nymphs, which constituted 84.62 per cent of the organic contents, was the only animal food. Greater Scaup Aythya marila The gizzard of one greater scaup was collected on November 16, 1940. It con- tained grit material amounting to 1.0 cc. and no animal or plant structures. Oldsquaw Clangula hyemalis The gizzard of one oldsquaw duck was obtained in the fall of 1940. It contained ANDERSON: Foop Hasits or Micratory Ducks 323 2.7 cc. of material, of which 11.11 per cent (0.3 cc.) was grit and 88.89 per cent (2.4 cc.) consisted of plant and animal matter. Coontail made up the entire plant contents (41.67 per cent of the organic material), while fish bones, midges, and snails made up the animal contents (58.33 per cent of the organic material). PLANT FOODS Data derived from analyses of the con- tents of waterfowl gizzards collected in Illinois in the autumns of 1938, 1939, and 1940 were used in making evaluations of the most important plants utilized as food by waterfowl migrating through the state. Although no completely satisfactory evaluations of the importance of various kinds of food plants are possible, a rough evaluation of each of the most important kinds was given by an index figure ob- tained by multiplying the number of giz- zards in which the kind of plant was found (occurrences) by the actual figure indi- cating the percentage it constituted of the total plant volume (for example, for Zea mays, multiplying 1,445 by 39.36, figures derived from table 38). The nineteen species of plants that were most utilized by ducks in their southward migrations through Illinois are listed in table 37. These plants were the favored Table 37.—Occurrence-percentage index ratings of plant foods identified in duck gizzards collected along the Illinois River, Ottawa to Florence (4,505 gizzards), and along the Missis- sippi River, Rock Island to Quincy (472 gizzards), 1938-1940 (derived from table 38). PLANT INDEX NuMBER Zea mays, corn. be I ences Leersia oryzoides, rice cutgrass. . J Polygonum coccineum, marsh smartweed.. Ceratophyllum demersum, coontail.. Echinochloa crusgalli, wild millet....... Potamogeton nodosus, longleaf pondweed. . Cyperus erythrorhizos, red-rooted nut- -grass.. Acnida altissima, water-hemp.. Polygonum lapathifolium, nodding smartweed.. Cephalanthus occidentalis, buttonbush. Polygonum pensylvanicum, nee seeded ae Re tor tee Cyperus strigosus, nut-grass.. Cyperus esculentus, chufa.. Echinochloa walteri, Walter’: S ‘millet. . Potamogeton pectinatus, sago pondweed. LEE lee aaa eae Scirpus fluviatilis, river-bulrush. . Eragrostis hypnoides, teal grass. : Sparganium eurycarpum, giant bur-reed. . 324 Intrnois NaturAL History Survey BULLETIN Vol. 27, Art. 4 Table 38.—Plant foods of ducks taken along the Illinois River, Ottawa to Florence (4,505 gizzards), and along the Mississippi River, Rock Island to Quincy (472 gizzards), 1938-1940. I-tinois RIver Mississippi River Occur- Occur- PLANT rence ‘ean . er a rence (ee ak inl T ey Centi- | Organic eer Centi- | Organic oe sy; meters) | Contents si dey meters) | Contents TOTAL PLAN Te oy cident tate ieee 94.82 ).........|1 ,S4eaee 90.36 Zea mays, corn. Sc ae 1,262 |6,429.05 35.38 183 | 883.20 59.44 Leersia ory zoides, | rice cutgrass. . eats 880 |2,339.58 12.87 41 52.62 3.54 Ceratophyllum demersum, coontail. . 795: 151.63 9.64 14 24.10 1.62 Echinochloa crusgalli, wild millet.............. 669 |1,165.32 6.41 46 30.22 2.03 walteri, Walter’s millet........... 243 | 410.67 2.26: |... + 2 soins |. «oe sen PlereteestAhe rds Soin: apkacre tee snes cine 2 1.40 0.01 Cyperus erythrorhizos, red-rooted Shs coer 613 | 683.11 3.76 + 6.90 0.46 Sirignsls (HUE-BTASS . S25! Le ae 378° | 289.13 159 6 3.60 0.24 SSCUIENELS CUA B62. oe alee ato 384 | 267.42 1.47 1 t ; ferax..... ree ene apis Reser 3 0.20 t 4 0.70 0.05 Unidentified. . SERS eee as 20 47.78 0.26 Bers Polygonum coccineum, marsh smartweed...... 1,995 | 760.02 4.18 17 1.32 0.09 lapathifolium, nodding smartweed.. 1,028 | 161.01 0.89 117 19.65 1 ae pensylvanicum, large-seeded smart- ska = * Cee ete 480 | 141.63 0.78 119 56.19 3.78 hydropiperoides, mild water-pepper. 219 82.32 0.45 6 0.40 0.03 punctatum, dotted smartweed..... 173 35.31 0.19 36 21.36 1.44 persicaria, lady’s thumb.......... 101 11. 71 0.06 15 6.25 0.42 Aydropiper, water-pepper. . 61 6.15 0.04 28 4.00 0.27 scandens, climbing false buckwheat 7 0.33 t 4 0.15 0.01 sagittatum, arrow-leaved tearthumb 2 0.20 t 1 0.40 0.03 amphibium, water lady’s thumb.. 1 0.05 t 3 0.02 t aviculare, prostrate knotweed..... Re eee late ae eta ae mb oneear= 1 t RIMGEMEHER Sc)25ts pa os Sik Sig Silt 15 Dedt 0.01 4 1.70 0.11 Potamogeton nodosus, longleaf pondweed....... £5252" | 329065 1.81 22 5.40 0.36 pectinatus, sago oe Cala peer aie te 596 | 104.22 0.57 34 21.77 1.47 foliosus, leafy pondweed.......... 179 40.03 0.22 42 14.10 0.95 pusillus, small pondweed.......... 98 17.76 0.10 6 0.87 0.06 perfoliatus, thoroughwort pondweed 3 8.40 0.05 se es eee: praclongus, white-stem pondweed. . 5 1.70 0.01 RE amplifolins, \arge-leaved pondweed_ 2 0.11 t oats een epthydrus, ribbon-leaf pondweed . 2 0.05 t 2 1.30 0.09 gramineus, variable-leaf Bae 2 Vong seal ics gall cnintae eetoen 1 0.40 0.03 Unidentified. . me Seas: 44 2.04 0.01 § 0.20 0.01 Acnida altissima, \ w jater-hemp. nia toe 691 | 494.59 2292 4 0.32 0.02 Sagittaria latifolia, oe ea aOR a. ere 156 | 254.41 1.40 11 3.44 0.23 CUCM, WADALO’ cas 333s lee as 1 0.50 t Soe Re ae Unidentified. . 2 1.31 0.01. |... a... Sa] cee Cephalanthus occidentalis, buttonbush 660 | 252.88 1.39 30 4.77 0.32 Eragrostis hy pnoides, teal aes soe Paige 114 | 188.71 LOA SH tupac Unidentified. . RE ye ae teas 2 0.40 t ine (a bua pov flaca as. nee eer Triticum aestivum, PRA IIS GPs 46 | 169.90 0.93 1 4.40 0.30 Lemna minor, lesser duckweed........... 152 95291 0.53 8 8.30 0.56 RMIIPSCIC cist os So ns a Sia sce 2 3.20 0.02: |. eccd ss «5 [ys pe ae August, 1959 Table 38.—Continued. PLANT Sparganium eurycarpum, giant bur-reed........ Wnirdentincdeeens Sc Scab ee Sasenne Scirpus Winviatilis, river-bulrush.......... . atrovirens, green bulrush..... .... acutus, hard-stem bulrush......... validus, soft-stem bulrush......... paludosus, alkali bulrush.......... americanus, American bulrush. .. . . Unidentified... Algae. elimi ‘lutea, American lotus... Quercus alba, white oak. palustris, pin oak. Ae Unidentified acorns......... ean Te dae common buck- wheat. . : Rumex masimus, pale dock .......+.5. mectosciia, field’sorrel.......2. +». + Winidentifiedas:.-.22.c%.2-.<54:- Bidens frondosa, poeeeoe ticks. Unidentified. . ee Ambrosia artemisitfolia, common ragweed... . trifida, great ragweed . fe: psilostachya, western ragweed ae ae Unidentified . Te eyes Najas guadalupensis, southern naiad ... flexilis, northern naiad.... . .... Winidentificdien.. 6 4.. 2.1.0.5 Eleocharis palustris, common spike-rush. .. obtusa, blunt spike-rush... ... . parvula, dwarf spike-rush ...... Unidentified. . Heteranthera dubia, mud- plantain. . Funcus, bog-rush. . eee Bark, roots, and wood. . Ranunculu: , buttercup. . Nymphaea tuberosa, yellow. water- lily Chenopodium album, \amb’s-quarters. . Unidentified. . Alisma subcordatum, water- plantain. Salix, willow. . Pe ce Cornus, dogwood. . Lippia "lanceolata, fog-fruit.. Vigna sinensis, cow-pea.. Myriophyllum Bophylen, water-milfoil . Unidentified. . ifs Ittinois River ANDERSON: Foop Hasits or Micratrory Ducks W bo nn Misstssipp1 RIveR Occur- Volume rence, (Cubic (Number Ce : of Giz- Sabi ae meters) 286 60.36 134 31.74 464 47.97 3 9.50 171 8.90 i 3.58 5 3.30 Tal Nea) 45 58.29 43 55.60 3) 16.90 sg) 3840 8 37.40 62 27.05 1 t 10 0.08 11 20.68 29 1.95 28 7.94 20 Je55 85 1.07 1 0.65 18 14.35 16 1.10 3 1.30 69 8.44 99 4.22 1 2.00 8 t 5 14.30 24 12.58 8 8.15 7 8.10 10 6.58 1? 6.41 1 t 1 6.20 16 (5. 117/ 75 6.04 219 5.60 1 5.20 10 0.50 60 4.23 Per Cent of Organic Contents mW os: ossss ss oooodw NNMnMN ~sIW Wo: Noe: os eS -1G9 Oo —_— Occur- rence (Number — . Ne: DSi we wwe ok! co 00 tO i) ey - OONn: - w- Per Cent of Organic Contents 326 Intrnors Narurat History Survey BULLETIN Vol. 27, Art. 4 Table 38.—Continued. I.trnors River Mississippt River Pass neg Volume | Per Cent Se ca Volume | Per Cent (Cubic of (Cubic of (Number A -_ | (Number : : a Centi- | Organic . Centi- | Organic of Giz- of Giz- : meters) | Contents meters) | Contents zards) zards) Spartina pectinata, prairie cord-grass . 2 4.20 0.02 Carex rostrata, beaked sere as sk ones eens cr ea 1 0.10 0.01 Unidentified. . 33 4.13 0.02 9 3820 0.22 Lophotocarpus.. 12 4.10 0.02 jee ae [pomea hederacea, ‘ivy-leaved morning- glory. 35 4.04 0.02 1 t' fea eee Zannichellia palustris, horned d pond weed. . at 5 3.60 0.02 3 ae Mee Sida spinosa, prickly s sida. . ne 34 3.56 0.02 5 0.20 0.01 Gramineae. . oe 3.30 ().02 areas oe Paspalum ciliatifolium, ciliate-leaved Peak can Set fe «ep Reeve 2 3/25 0.02 1 1.50 0.10 Rien ited 2.25 okies eines oe 1 t Age Ree Vitis cordifolia, frost Brapes: 4 0.25 t 2 2.50 0.17 Unidentified. . ee 56 2.82 0.02 10 17.72 1.19 Potentilla, cinquefoil. . 1 3.00 0.02 sages a Digitaria sanguinalis, crab-grass.. Bae 3 2.50 0.01 2 0.30 0.02 ischaemum, smooth crab- _grass. Ra 4 0.30 t 2 0.50 0.03 Anacharis canadensis, waterweed..... 1 2.10 0.01 Sra eee Rete Panicum dichotomifiorum, fall panic-grass.. . . 38 1.90 0.01 7 4.90 0.33 capillare, old-witch grass.......... 18 0.11 2 s:| |S aaheeee Beatenavyiciccs ioe ie see 1 1.50 0.01 ae Verbena hastata, blue vervain. 1 0.80 t 52 Sra ae Unidentified. . 4 0.05 t ee SN Abutilon theophrasti, velvet-leaf . 37 0.83 t 1 0.03 t Hibiscus militaris, scarlet rose-mallow...... 2B 0.50 t 2 t Unidentified.... 5 0.06 t on Setaria italica, German millet............ 3 6.40 0.04 Rae Be: glauca, yellow foxtail............. 17 0.50 t 5 0.10 0.01 Drid¢ussoreen, toxXtalles i...) teas 1 t 1 t eae Celtis occidentalis, pack Bein errr 1 0.50 t ‘aa Compositae.. Shane tots 1 0.40 t Crataegus, hawthorn... 2 0.30 IE Solanum, nightshade. . ase 1 0.30 t EAE 5 ao ena 1 0.30 t Rhus glabra, smooth sumac. 18 0.18 t ff 0.20 0.01 radicans, poison ivy. 6 0.10 1 t | ange Unidentified. 1 t 1 ee Phaseolus, wild bean. . 1 0.20 t Pa Strophostyles helvola, trailing wild bean. . 1 0.10 t Unidentified. . se 2 t Pontederia cordata, heart-shaped | pickerelweed...... ye re? 2 0.08 t wii ae Cladium mariscoides, twig-rush. dec era 16 0.07 t 2 0.04 t Cassia fasciculata, partridge-pea Deer: 1 0.03 t SAAN Boas - Amaranthus retroflexus, green amaranth........ 1 t |iisire [riot (2 ee oe see 1 0.01 t August, 1959 ANDERSON: |*oop Hasits or Micratory Ducks 327 Table 38.—Continued. I-tino1s River Mississippi River Bee Sa Volume Per Cent ares Volume Per Cent (Number (Cubic = (Number (Cubic of | 6 Gin: Centi- | Organic |*o¢ Gg, | Centi- | Organic ade) meters) | Contents aed meters) | Contents Rubus Alagellaris, northern eek eee 4 0.02 t aie Unidentified. . 2 a eee 5 t ay oe ae Ammannia coccinea, ~tooth- cup. nou See eee | Meni + 3.10 0.21 Avena sativa, oats. oe 1 t sae arAaes ie Convolvulus arvensis, ' field- bindweed. | ee ce Noa 1 t Soa Cuscuta, dodder . Ae eae, care 7 t 3 0.10 0.01 Diodia teres, buttonweed. . Da ere 1 t ae ane en Geum, avens. ¥ Recs Noe te 1 t Phytolacca americana, common pokeweed. 5 t 1 t Neier Portulaca, purslane. . sid Bet ake | pre Ay gs (nee ae 1 2.30 0.15 Rosa, rose. ees oa aoe 3 t Bae Lust ote octet Sorghum vulgare, sorghum. . oe Baie 1 1.40 0.09 Prunus, cherry. . 2 t ahs Sti Symphoricarpos orbiculatus, coral- INS VAP Re gr Ny STR ANT at cis ail is Thneneloees ill esatageeer are 5 1.10 0.07 Trifolium, epee oe 1 t oh eg Sere Sea alien ee cee Unidentified plant. . 73 63.68 0.35 23 18.09 122 ones in each of the 3 years of this study; from year to year the relative positions of some of them changed within the group as a result of changes in abundance or acces- sibility. Food plants favored by the various spe- cies of ducks differed with the feeding hab- itats of the birds. Foods utilized by ducks of the teal size were mainly from small- seeded plants, while those utilized by the mallard were principally from corn and from large-seeded native wild plants. The puddlers fed principally on emergent and moist-soil plants, while the divers fed largely on submergent plants. “here were exceptions in each waterfowl group, how- ever, such as the gadwall and the baldpate, which fed primarily on a submergent plant, coontail, and the ring-necked duck and the redhead, which fed extensively on emergent plants. Of the plants represented in the giz- zards collected for this study, 95 native wild plants and + domestic plants were identified to species, table 38. The 19 im- portant species listed in table 37 and dis- cussed in the following pages constituted 92.91 per cent of the total plant material. Analyses of gizzard contents showed that the plants increased or decreased in use- fulness to ducks during the fall season as weather conditions and water levels var- ied. Corn Zea mays Corn was the most important food both in volume and in number of duck gizzards in which it was found (occurrences), table 38. It comprised 37.20 per cent of all or- ganic foods in the gizzards, primarily be- cause it was the staple food of the mallard, which made up over 50 per cent of the duck flight. It appeared in 1,445 gizzards, of which 86.92 per cent were mallard and 9.55 per cent were pintail. Of the 26 wood duck gizzards that were collected, 11 contained corn. Use of this grain depended largely upon the time of corn harvest. In 1939, corn ripened early, and harvesting was well along by October 15; in that year, mal- lard gizzards collected early in the season were gorged with kernels of waste corn. However, in 1940, corn harvesting did not commence until late in October or early November, and native wild foods appeared in gizzards in large volumes until the waste corn was available. The volume of corn increased from October 16 to De- 328 InuiNots NarurAL History Survey BULLETIN cember 15, even though the number of duck gizzards containing corn decreased. Rice Cutgrass Leersia oryzoides Rice cutgrass, fig. 6, was shown by this study, tables 37 and 38, to be the most important wild native food plant in Illinois during the autumn. This plant was spotty in distribution, but apparently wherever the seeds, rootstocks, and tender shoots were accessible they were avidly consumed. Pintails and mallards were the most important consumers. As many as 2,000 seeds were taken from a single pin- tail gizzard. Plant structures of rice cutgrass, found in 921 duck gizzards, comprised 12.17 per cent of the entire organic contents of the 4,977 gizzards examined. Rice cutgrass provided a good, staple food throughout the fall months. The volume of rice cut- grass structures in gizzards decreased gradually from 16.83 per cent of the plant Fig. 6.—Rice cutgrass (Lecrsia oryzoides), known also as saw-grass. This plant grows on moist soil in shallow water. Ducks feed on the seeds and rootstocks. Vol. 27, Art. 4 ewrr. ee August, 1959 foods in late October to 11.75 per cent in early December. Marsh Smartweed Polygonum coccineum Marsh smartweed, fig. 7, ranked fourth among wild native food plants in percent- age of total organic contents of the duck gizzards examined, table 38; it was second among wild plants and third among all plants in the occurrence-percentage index rating, table 37. In the region and years of this study it was an abundant plant, but ANDERSON: Foop Hasits oF Micratory Ducks 329 in much of the region it was low in seed production. In a few areas where water level conditions were favorable, it pro- duced an abundance of seeds in 1938 and 1939. Because of sporadic seed production (Low & Bellrose 1944:14), this plant varied from year to year in usefulness as a source of duck food. All important spe- cies of ducks fed on the seeds, but these seeds seldom made up the bulk of the plant food for any one duck. Marsh smartweed seeds were found ina large number of gizzards (2,012), but Fig. 7—Marsh smartweed (Polygonum coccineum), sometimes called redtop because of its pink-red blossoms. When it grows in water 6 to 18 inches deep it produces seed that rates high as duck food. 330 Iturnors NatrurAL History Survey BULLETIN = never in large quantities. Because the seeds drop early in the fall, this smartweed is considered a good early season source of food. In October, this plant represented 5.50 per cent of the plant food but, by early December, only 1.85 per cent. Marsh smartweed rated as an important baldpate and gadwall were the most avid feeders. During October, when waste corn was scarce, mallards fed extensively on coontail. Coontail structures, which were found in 809 gizzards, represented 9.03 per cent of the total organic contents of all giz- _ a — — ie Saale ein sty —oeere ss) Fig. 8.—Coontail or hornwort (Ceratophyllum demersum). A favorite food of baldpates, gadwalls, and ring-necked ducks, it grows best in stable or semistable waters that are fairly clear and protected from wave action. Ducks feed principally on the leaves and stems. waterfowl food plant despite the relatively small quantities of its seed ingested by in- dividual birds. Coontail Ceratophyllum demersum Coontail, fig. 8, which occurred com- monly in all stable and semistable water areas involved in the study, ranked second among wild native food plants in percent- age of the total organic contents of all duck gizzards examined, table 38, but it rated fourth in the occurrence-percentage index, table 37. Seed production of coontail was low in the years of this study; leaves and stems were the principal structures found in the gizzards. This study showed that all species of ducks of which there was an adequate sample fed upon this plant; the zards. Analyses showed that utilization of coontail rapidly decreased during the fall season, from 16.84 per cent of the volume of plant foods in October to 2.20 per cent in December. Despite the decrease in vol- ume, coontail appeared to be an important source of food through most of the fall. Wild Millet Echinochloa crusgalli Because some difficulty was experienced in separating the seeds of wild millet from the seeds of Japanese millet, Echinochloa frumentacea, undoubtedly some _ seeds classified as wild millet were those of the Japanese species. However, in the years in which gizzards were collected for this study, the acreage of Japanese millet in Illinois was comparatively small. Vol. 27, Art. 4 August, 1959 Wild millet, fig. 9, ranked third among wild native food plants in percentage of the total organic contents of all duck giz- zards examined, table 38. Although its occurrence was spotty in the Illinois and Mississippi river valleys in the years of this study, it ranked fifth in the occur- rence-percentage index, table 37. During 1939 and 1940, water level conditions in some areas were very favorable for luxuri- ant growth and heavy seed production of millets (Bellrose 1941:253). Seeds of the wild millet were found in the gizzards of most ducks and were especially numer- ous in those of pintails, mallards, and green-winged teals. A few pintail gizzards held as many as 1,000 seeds each, and the craws another 3,500. Wild millet seeds or other plant parts appeared in 715 gizzards and constituted ANDERSON: Foop Hasits oF Micratory Ducks 331 6.08 per cent of the total organic contents of the gizzards examined. The heaviest consumption of wild millet occurred in October, when this plant represented 10.76 per cent of the plant foods in the gizzards; the consumption decreased to 3.90 per cent by December, probably as a result of a decline in availability of millet seed and a shift by the mallard and the pintail to a corn diet. Because the seeds remained on the plants until late fall, wild millet proved to be an excellent source of food for ducks; also, the rank stem growth provided pro- tective cover. Longleaf Pondweed Potamogeton nodosus The longleaf pondweed, fig. 10, is con- sidered one of the good duck food plants Fig. 9.—Wild millet (Echi- nochloa crusgalli). Known also as barnyard-grass, this moist- soil plant produces seeds that are consumed in large quantities by mallards, pintails, teals, and other ducks. The inset shows wild millet growing on a mud flat from which water has re- ceded. In 1939 and 1940, water levels along the IIli- nois River were especially favorable for growth and seed production of millets. The millets provide cover as well as food for ducks. ae w bo in many parts of the United States. In Illinois, it was present in small amounts in nearly all the river-bottom lakes in the region and years involved in the present study; usually it produced an abundance of seed. In the gizzards of all important species of waterfowl included in this re- port, the seeds and occasionally the stems or leaves were found. Longleaf pondweed plant parts, found in 1,274 gizzards, amounted to 1.70 per cent of the total organic contents of all gizzards examined, table 38. It ranked sixth in the occurrence-percentage index, table 37. Apparently, use of this plant varied from one period to another, but at no time did it constitute more than a sup- plemental food. Red-Rooted Nut-Grass Cyperus erythrorhizos Red-rooted nut-grass, a moist-soil plant that grows on mud flats and mud banks of both the Illinois and Mississippi river valleys, ranked sixth among food plants in percentage of total organic contents of gizzards examined, table 38, and seventh in the occurrence-percentage index, table 37. Because growing conditions were I~Linois NaturAL History Survey BULLETIN Vol. 27, Art. 4 much better for plants of this type in 1939 and 1940 than in 1938 (Bellrose 1941: 252-3), the volume of seed and its acces- sibility to ducks was greater. This nut- grass was found in significant amounts in the gizzards of several of the important duck species; it made up the largest per- centages of organic material in gizzards of the blue-winged teal, green-winged teal, and shoveler. In most cases, the entire seed head had been clipped off; in other cases, individual seeds had been strained from the bottom ooze or from the water surface. Some pintail gizzards contained amounts estimated at 25,000 seeds each. This plant was represented in 617 giz- zards, table 38, and constituted 3.71 per cent of the plant contents or 3.51 per cent of the total organic contents of all duck gizzards examined. There appeared to be little change in the rate of its utilization as the fall months advanced. This nut- grass appeared to be an excellent all-season duck food. Water-Hemp Acnida altissima Water-hemp, or pigweed, fig. 11, an important moist-soil plant that occurs on Fig. 10.—Longleaf pondweed (Potamogeton nodosus), known also as deer’s tongue. Ducks feed on the seeds of this plant. , Fig. 11—Water-hemp or pigweed (Acnida altissima). This plant grows well on mud flats. mud flats, ditchbanks, and similar areas, is a good source of duck food in seasons favorable to its growth. It ranked eighth in the occurrence-percentage index, table 37. This plant is subject to poor seed yields when growing conditions are un- favorable, such as occurred in 1938 and 1939. In those years, it was represented in only about 1 per cent of the total or- ganic contents of the duck gizzards exam- ined, but in 1940, a year in which beds were abundant and luxuriant, its volume increased to 8.18 per cent. The puddle ducks, especially the mallard, pintail, and both teals, used this plant. It was not un- common to find 40,000 seeds in a mallard gizzard, or 25,000 to 30,000 in a pintail or teal gizzard. Only the seeds and seed heads of this plant were used. Water-hemp seeds or seed heads, found in 695 gizzards, table 38, made up 2.52 per cent of the total organic contents of all gizzards included in this study. Appar- ANDERSON: Foop Hasits or Micratory Ducks 333 ently, the usage of this food plant through- out the fall changed little as long as the seeds were accessible. An early freeze would probably have lessened its use, but the 1938-1940 study did not indicate any decrease in percentage of use as the season progressed. Water-hemp can be consid- ered a good all-fall food for most species of dabbling ducks. Nodding Smartweed Polygonum lapathifolium Nodding smartweed, fig. 12, grew abun- dantly along the margins of most Illinois rivers and bottomland lakes in 1938- 1940. Gizzard analyses showed that most of the important species of waterfowl fed on the seeds in significant amounts. Seed, produced in abundance, seemed to serve principally as a supplemental food, as it never constituted a complete feeding. Seeds of nodding smartweed, present in 1,145 gizzards, table 38, constituted 0.92 per cent of the total organic contents of all gizzards examined. The period of 1 Fig. 12.— Nodding smartweed (Polygonum lapathifolium). The long, drooping, densely flowered spikes distinguish this plant from other smartweeds. 334 ILLINoIs NATURAL History SuRVEY BULLETIN greatest consumption occurred the latter half of October; during the fall the pro- portion of these seeds in the gizzards dropped from 1.62 per cent to 0.56 per cent of the plant foods. This smartweed can be considered only a fair source of all-fall food, except lo- Lees ae 7 a cS Ue | Fig. 13.—Large-seeded smartweed (Polyg- onum pensylvanicum), known also as Penn- sylvania smartweed. A moist-soil plant, this smartweed ranked below marsh smartweed and nodding smartweed as an Illinois duck food in the years of this study. cally where the plant is easily accessible. It ranked ninth in the occurrence-percent- age index, table 37. Buttonbush Cephalanthus occidentalis This shrub is very abundant in the val- leys of both the Illinois and the Mississippi rivers. Even though its seeds are a fair duck food, the buttonbush is not a desira- ble plant to have in a waterfowl] habitat, Vol. 27, Art. 4 as it tends to crowd out more favorable duck food plants. However, this shrub is less undesirable in a waterfowl habitat than lotus or river bulrush, which have lit- tle value as duck food plants. Seeds of the buttonbush were found in small quanti- ties in the gizzards of all important spe- cies of dabbling ducks. Present in 690 gizzards, the seeds of the buttonbush represented 1.31 per cent of the total organic contents of all gizzards, table 38. Throughout the fall season, the percentage of seeds consumed varied very little from week to week. Buttonbush may be considered as a fair supplemental duck food plant, table 37. Large-Seeded Smartweed Polygonum pensylvanicum The large-seeded smartweed, fig. 13, ranked eleventh in the occurrence-percent- age index, table 37. Utilization of this plant by ducks in II]linois was subject to change from year to year and place to place and was dependent principally on ac- cessibility. For instance, along the Mis- sissipp1 River, where this smartweed ap- peared to be easily accessible during the years of this study, it ranked first among native foods, table 38. The seed was the only part of this plant found in the duck gizzards examined. Seeds of this smartweed, in 599 giz- zards, table 38, made up 1.01 per cent of the entire organic contents of all gizzards. Apparently the seeds were eaten through- out the fall, but were more important in the diet during the latter part of Novem- ber and December than at other times. Nut-Grass Cyperus strigosus Like the red-rooted nut-grass, this spe- cies grows on certain mud flats and other moist areas. It ranked high among the im- portant foods preferred by the pintail, blue-winged teal, and green-winged teal in the years of this study. Apparently both seeds and seed heads were avidly con- sumed. Some pintail and teal gizzards contained as many as 10,000 seeds each. Structures of this plant, found in 384 gizzards, constituted 1.58 per cent of the total plant contents and 1.49 per cent of the total organic contents of the gizzards examined, table 38. Apparently heaviest rt ens ON ee he ee ee eee ir August, 1959 Fig. 14.—Chufa of several nut-grasses that grow on moist soil] (Cyperus esculentus), one in Illinois. Ducks feed tuhers. upon the seeds and use of this plant occurred during Novem- ber, when its principal consumers were most abundant. As with most moist-soil plants, in years and in places in which the seed was pres- ent and accessible, this nut-grass was a good source of waterfcwl food during the fall months. It ranked twelfth in the cc- currence-percentage index, table 37. Chuta Cyperus esculentus Chufa, fig. 14, occurred rather sporad- ically on mud flats, ditchbanks, and other moist ground in the areas from which giz- zards were collected. It was a preferred food of the blue-winged teal, green-winged teal, and pintail, which consumed seeds, seed heads, and tubers. Several hundred seeds were taken from a few of the teal gizzards. Structures of this plant were found in 385 gizzards and constituted 1.36 per cent of the total organic contents of the giz- _zards examined, table’ 38. As with the other moist-soil plants, chufa received the heaviest use during November. This nut- grass furnished good waterfowl food dur- ing the fall months when water conditions made the plants accessible. It ranked third ANDERSON: Foop Hasits or Micratory Ducks 335 among nut-grasses in the occurrence-per- centage index, table 37. Walter’s Millet Echinochloa walteri Although the seeds of Walter’s millet, fig. 15, are much smaller than those of the wild millet, they were eagerly consumed by the ducks represented in this study. Walter’s millet often volunteers in muck areas generally wetter than those contain- ing wild millet. Seeds of Walter’s millet were found in the gizzards of most puddle ducks—in relatively largest amounts in gizzards of the pintail, green-winzed teal, and blue-winged teal. The fruit is more y 4 Fig. 15—Walter’s millet (Echinochloa wal- teri), sometimes called corn grass. Its small seeds are consumed in considerable numbers by mallards, pintails, and teals. 336 persistent than that of the wild millet and is therefore available for waterfow] later in the season. Walter’s millet was represented in 243 stomachs, table 38, and constituted 2.09 per cent of the total organic contents of all gizzards. It is a good source of late- fall waterfowl food. It ranked fourteenth in the occurrence-percentage index, table Eve Sago Pondweed Potamogeton pectinatus Sago pondweed, fig. 16, according to Martin & Uhler (1939) is one of the most important duck food plants in the United States. In 1938-1940, this plant appeared to be relatively unimportant in Illinois; here the plant was spotty in dis- tribution and it produced very little seed (Bellrose 1941:266). Although sago ranked low among the important plants in the present study, table 37, most species of ducks, especially the divers, fed on the limited seed supply, tubers, and leaf struc- tures. Portions of the plant, found in 630 giz- zards, represented only 0.64 per cent of CRS SSS SS } n \ as A % “ — SS ~< Intinois NaturRAL History Survey BULLETIN Vol. 27, Art. 4 the total organic contents of all gizzards examined, table 38. In no half-month pe- riod did it vary considerably in volume or number of occurrences from the average. If this plant had been more abundant and if it had produced more seed, it un- doubtedly would have ranked much higher in the food preference list. Duck-Potato Sagittaria latifolia The duck-potato, fig. 17, was shown by this study to rank low among the import- ant duck food plants in Illinois, table 37. Although it occurred sparingly in the areas from which gizzards were collected in 1938-1940, it produced a moderate amount of seed (Low & Bellrose 1944: 13). Analyses of gizzard contents showed that most species of waterfowl fed on the seeds and tender roots; however, only the large ducks were able to use the tubers. The usefulness of this plant seemed to be partly dependent upon accessibility—on water levels sufficiently high to allow the ducks to feed in the duck-potato beds. Structures of this plant, found in 167 gizzards, comprised 1.31 per cent of the a ” Nick Saige Ss SS ON ‘ 7 SSTRARS Sey \ Fig. 16.—Sago pondweed (Potamogeton pectinatus), known also as teal grass and eel grass. Ducks feed upon its seed, foliage, and tubers. August, 1959 Fig. 17.—Duck-potato (Sagittaria latifolia), known also as arrowhead, wapato, or boot- jack. Ducks value it more for its seed than for its tubers. total organic contents of the gizzards col- lected for examination, table 38. The plant apparently increased in duck food value as the fall season waned. In Octo- ber, it represented less than 1 per cent of the plant contents of gizzards, but 3 per cent by December. This plant may be considered a fair duck food throughout the fall, increasing in importance as the season advances. River-Bulrush Scirpus fluviatilis River-bulrush seeds occurred in about one-tenth of the duck gizzards collected in 1938-1940 from areas along the IIli- nois and Mississippi rivers, table 38. “The total quantity of river-bulrush seeds was only 0.29 per cent of all the organic food. The number of gizzards in which river- bulrush seeds were found (510) is con- sidered large in view of the fact that seed production of this plant is poor in IIlinois (Bellrose & Anderson 1943:430). Evi- dently the seeds are very palatable. Teal Grass Eragrostis hypnoides Teal grass was found to be another moist-soil plant that ranked among the ANDERSON: Foop Hasits or Micratrory Ducks BLY important sources of duck food in the pe- riod of this study, table 37. Under cer- tain conditions, when water levels were sufficiently high to flood the plants grow- ing along ditchbanks and mud flats, it ranked much higher than when conditions were less favorable. It appeared among the important native foods because of large numbers of seeds consumed by a relatively small number of ducks. The green-winged teal, blue-winged teal, and pintail fed more upon this plant than did other spe- cies of ducks. Seeds of teal grass, found in 114 giz- zards, constituted 0.96 per cent of the total organic contents, table 38. After Novem- ber 15, utilization of this plant rapidly de- creased. The drop was due partly to ice fringes that prevented ducks from having access to the seeds and partly to a decrease in numbers of the ducks that were the principal consumers of these seeds. Teal grass may be considered a fair source of early-fall food but a poor source of late- fall food. Giant Bur-Reed Sparganium eurycarpum Giant bur-reed occurred in small beds scattered among the bottomland lakes of the Illinois River valley in the years giz- zards were collected for this study. De- spite the very limited occurrence of giant bur-reed, a comparatively large number of gizzards, 286 from the Illinois River val- ley and 24 from the Mississippi River val- ley, contained seeds of this plant, table 35. The high rate of utilization indicates that ducks found the nutlike seeds of the giant bur-reed very palatable, but that the small quantity available limited the importance of giant bur-reed, which ranked last among the 19 most important plants, table ad. ANIMAL FOODS This study indicated that animal foods were not important in the diet of most species of waterfowl migrating through Illinois in the autumns of 1938, 1939, and 1940, although impressive numbers of ani- mal groups were found in the gizzards collected. The lesser scaup duck, ring- necked duck, shoveler, blue-winged teal, and green-winged teal were among the 338 Ittinors NarurAL History Survey BULLETIN Vol. 27, Art. 4 Table 39.—The most important animal foods of ducks taken along the Illinois River, Ottawa to Florence (4,505 gizzards), and along the Mississippi River, Rock Island to Quincy (472 gizzards), 1938-1940. Ittrnots River Mississipp1 River Occur- Volume | Per Cent Occur- Volume | Per Cent ANIMAL rence (eae ; rence Cubi f (Number eto oO. | (Number (Cubic e of Giz. Centi- | Organic SCE. Centi- | Organic shal meters) | Contents mas dic) meters) | Contents TOTAL ANTAL 550. sh eases PE ee ae SAG We i ee 9.64 BRYOZOA, moss animals.......... 136 9.97 0.05 MOLLUSCA GASTROPODA, snails Stagnicola....... a ava snes Sem Cie 3 5.70 0.03 |. 02... 4.3). PIGHOPDIS aia i ink Ole constens erate 2 1.50 0.01 2 t Bia PV CTES DING ste Paso ia thse a) Se 3 1.17 OLOL A. ke See : Oa GYFAUIU Seon s,s niin hoe ere i, 0.58 t pir: 5M 22 COPENIER nd sane nee eee 1 0.40 t eat a8 me PRS re ok cies esd weiss Perea a 7 3.40 0.02 1 t Pe) PADD S aie gro Be tee ss 2 4.90 0.03 1 0.20 0.01 CMIEDEIOM Ee 5 ode Px GO 26 34.20 0.19 9 11.80 0.79 MAORTA oe eet tere eee 8 3,25 0.02 2 1.80 0.12 PAVIA COND: (dato RO an 45 43.15 0.24 10 13.80 0.93 Elampnicola ta hea tek 4 5.50 0.03 3 3.10 0.21 yes le a Sr An pee AS 3 0.90 t 1 0.80 0.05 Pleurocera.. 16 5.50 0.03 j2 0.30 0.02 Neritina.. inka 2 2.50 OVO |i: eee |e A Pe Unidentified Gastropoda... erat: 167 | 143.49 0.79 12 10.78 0.72 PELEcYPODA, mussels Sphaeriidae PESSQIUIE UREN Roe eR ae 15 17.70 0.10 4 5.90 0.40 IMIBSCUI MIT aa ee 20 27.50 0.15 1 2.70 0.18 Sphacrium.... rae 45 94.50 0.52 11 16.20 1.09 Unidentified Sphaeriidae. . ay 6 23.30 0.13 + 13.70 0.92 Unionidae, fresh-water clams. . 9 10.80 0.06 9 4.89 0.33 Unidentified Pelecypoda........ 28 17.64 0.10 2 2.80 0.19 UnipenTiFIeED MoLuusca......... 81 48.94 0.27 13 18.50 1.24 ARTHROPODA CRUSTACEA Brameinonodas 80 vk oe es 3 1.40 0.01 San COREpOEA ek Sor 3a ee eee 9 4.30 0.02 ae Ostracadacc sons con Sop 105 4.20 0.02 |. Bhat Mialaeost rate kc cuentas 27 18.91 0.10 2 2.50 0.17 INSECTA Orthoptera.. : ori 3 0.52 t 1 t{) ea Neuroptera, hellgrammites. . See 1 0.50 t As Bekemeconies, mayne: 7 Sas Sea nace aie 80 31-25 er 29 13.68 0.92 CACHIS TFS Nate Bits eee oe 2, 0.10 t Gone Odonata Anisoptera, pace eal Bae 9 2.80 0.02 4 2.10 0.14 Zygoptera, damselflies........ 17 14.00 0.08 1 t ..|: ce Unidentified Odonata........ 6 3.60 0.02) )..0 5.08 oe aah er Homoptera Cicadellidae, leafhoppers... . . 3 0.20 t 1 t Le ; Hemiptera Corixidae, water boatmen.. 329 | 128.52 0.71 37 4.33 0.29 Notonectidae, backswimmers.. 2 oy yen le Wee er Nepidae, waterscorpions. . 2 uw wvlry whales ceva | Belastomatidae, water bugs. 22 T7735 0.10 1 0.12 0.01 Gerridae, water striders. . 2 . Bu. mel Bee». See er Miridae, Lygus, plant bugs. . 1 Lygaeidae, chaiteh begsse os vee 1 August, 1959 ANDERSON: Foop Hapits oF Micrarory Ducks 339 Table 39.—Continued. Ittinots River Misstssippt River A Occur- Volume | Per Cent Oceur- Volume | Per Cent eee Ree oll «(Cubic of For (Cubie of (Number Cand O - | (Number eae O : PGi enti- rganic | * 5 Gi ‘enti- rganic SS meters) | Contents zards) | meters! Contents oreidae, squash bugs........).020.... Bee 1 0:12 0.01 Pentatomidae, stink bugs... . . 3 0.40 t £3 See eee ee eras Unidentified Hemiptera....... 5 0.57 t Coleoptera Carabidae, ground beetles..... 46 Sp. 0.01 8 One 0.01 QUO BIGOT Er sates tas Od a aS aa Se ae 1 0 20 0.01 Haliplidae. . e 3 0.17 € ae et aes Dytiscidae, diving beetles. . D277, 23297) 0.13 8 0.35 0.02 Gyrinidae, whirligig beetles. . . 8 0.37 t 1 0.10 0.01 Hydrophilidae, water scaven- ger beetles. . is = 6 0.90 t 4 6.00 0 40 Staphylinidae, r rove beetles. ... 6 0.29 t are eee Puprestidae, fatheaded wood orerss 4-4-5 J t Drvopidae... 2.20.00... 1 t Elmidae ; 2 t 5 the intel Scarabaeidae, scarab beetles. . 6 0.86 t 3 0.27 0.02 Chry somelidae, leaf beetles... 12 0.50 ey Bec Curculionidae, snout beetles . 17 2.90 0.02 3 0.20 0.01 Unidentified Coleoptera. .... 6 0.55 t cA ee Trichoptera, caddisfies Hydroptilidae. . 132 Se, 0.03 | t Hydropsychidae. 5 ee tae oe 13 11.66 0.06 Unidentified Trichoptera sco 19 PAIL 0.01 cae ee Lepidoptera.. ee 4 0.39 t 1 0.09 0.01 Diptera, flies Chironomidae, midges........ 238 127.61 0.70 10 4.70 0.32 TVabanidae, horse fiies.......- 2 0.50 t Hens ene Anthomyiidae. . Ronit te 1 0.09 t 1 0.20 0.01 Unidentified Diptera. . 14 5.63 0.03 0.10 0.01 Hymenoptera Ichneumonidae, ichneumons. . 3 0.05 t tA: Tiphiidae, Tiphia, tiphiid wasps 22 0.10 t ne a Formicidae, ants. 6 0.10 t 2! 0.08 t Unidentified Hymenoptera. 1 0.96 t oid at ee Unidentified Insecta. . et 15 5.09 0.03 Pee Sie: ARACHNIDA....... ne Srat nee” 21 0.72 t 7 0.14 0.01 ACARINA, water mites. 75 0.37 t Abe ae CHORDATA Pisces, fish. eer 18 0.72 t 1 t AMPHIBIA, frogs... me 1 1.00 te [ae ee eset cy llb eons aon UNIDENTIFIED ANIMAL. .... 4 0.80 t 2 t NONFOOD PARASITIC WORMS oc. 32.5 002% 00: 1 0.20 t Ste eater ER RATENBIS Se iets aio ninie = va & 83 8.72 0.05 8 0.52 0.03 species that were the principal consumers of animal foods. Animal parts constituted 5.52 per cent of the organic contents of all waterfowl - gizzards collected in the years of the study. The two outstanding animal groups were mollusks and insects, table 39. The for- mer comprised 55.66 per cent of the total animal foods and the latter 39.32 per cent. Crustaceans comprised 2.89 per cent of the animal foods. Mollusca Snails comprised 49.47 per cent of the Mollusca and 27.54 per cent of the ani- mal foods, while mussels constituted 39.36 340 Intrnois NatrurAL History Survey BULLETIN per cent of the Mollusca and 21.90 per cent of the animal foods, table 39. Fresh-water snails found in the largest numbers of duck gizzards were 4 mnicola, Campeloma, and Pleurocera. Fragments of a brackish water snail, Neritina, were found in two gizzards. ‘he mussels iden- tified were of no commercial use; most of them were small and thin shelled. Genera represented included Sphaerium, Pisidium, and Musculium. Insecta The insects represented 2.17 per cent of the total organic foods and 39.32 per cent of the total animal foods in the gizzards examined, table 39. Many species of in- sects were represented in gizzards collected prior to November 15, but after this date the volume and the number of species of insects decreased. This decrease was due in part to a decline in the populations of ducks that feed upon insects and in part to a decline in the number of insects avail- able. Among the insect material found in greatest volume in the duck gizzards were Odonata nymphs, midge larvae, mayfly nymphs, fig. 18, caddisfly larvae, and water boatmen. Crustacea In the duck gizzards collected, Crus- tacea constituted only a small portion of the animal foods, table 39; in greatest volume were the crayfish (Malacostraca). The minute forms appeared in many giz- zards but in negligible volumes; among them were water fleas (Branchiopoda), amphipods and pillbugs (Malacostraca), and ostracods. Bryozoa These small animal forms appeared most often as traces in the duck gizzards collected. “The winter buds or statoblasts of Pectinatella and Plumatella probably had been eaten along with other foods. Amphibia Frog bones appeared in only one giz- zard. Arachnida A few spiders and water mites were found in the contents of the gizzards col- Vol. 27, Art. 4 Fig. 18.—Mayfly nymph of the genus Hexa- genia. This is one of the animal foods con- sumed by ducks that migrate through Illinois in autumn, lected ; they were not considered important waterfowl foods. Pisces Fish vertebrae and scales were occasion- ally found in the duck gizzards collected. Mallards and black ducks have been known to feed extensively on gizzard shad, Dorosoma cepedianum. GRIT Generally grit is considered to have two functions in avian nutrition: (1) assisting the gizzard in the grinding of food and (2) furnishing necessary minerals for me- tabolism and reproduction (Nestler 1946: 137). Because grit invariably appeared in the gizzards examined in the present study, it seems reasonable to conclude that ade- quate supplies of hard, nonfriable particles were available to waterfowl in the Missis- sippi Flyway. Experiments with captive wild mallards have shown, moreover, that the grit demands of waterfowl may be low even in areas of grit abundance. When supplied with granite grit, each of 30 mal- lards under observation at the Havana lab- oratory of the Illinois Natural History Survey took an average of slightly less than one piece per day for a period of 1414 August, 1959 ANDERSON: Foop Hasits of Micratory Ducks 341 Table 40.—Grit contents of duck gizzards collected in Illinois, 1938-1940. AVERAGE AVERAGE AVERAGE SPECIES GizzarD CAPACITY cr as G PER CENT OF (Ciara (Caan ee ER GIZZARD IZZARD CAPACITY (Cusic CENTIMETERS)| OccuplieD By Grit lal levrd lc Sie a 16.0 2.95 18.44 FLAG. 9 14.0 Dei 16.50 6 2k OIE, ta ce ean a 13.0 2.87 22.08 (Cavalyailll © 60 ei pee ae 14.0 3.85 27.50 \ vera la bre) aa 9.0 1.91 DA 92) Green-winged teal............. 325 0.83 Deere T/il Pane-winged teal.............. S7/ 0.40 10.81 Snowe AS ee 6.0 Le vAl 28.50 Wanvasbacks os... as hens 14.5 3.01 20.76 fuel eave). <0 oe tee 14.0 2.78 19.86 | SS2 EG 0k Oe Sad 1.00 11.76 Ring-necked duck... 8.5 153 18.00 months. Though additional grit was eas- ily available, some mallards retained the same particles for as long as 714 months. Evidence of the ability of ring-necked pheasants and bobwhites to retain grit in their gizzards for 6 weeks or more has been presented by Gerstell (1942:72-9) and Nestler (1946:141). Grit as a grind- ing agent in the gizzards of the bobwhite quail, Colinus virginianus, was not essen- tial for growth, health, or reproduction, Nestler found. In gizzards collected for the present study, grit occupied an average of 10.81 to 28.50 per cent of the gizzard capacity in the various species of ducks, table 40. ‘The data indicate no correlation between amount of grit and size of duck, type of food (plant or animal), type of feeder (puddler or diver), or feeding habitat. Grit in the gizzards collected for the present study was composed principally of rough, angular particles of quartz and chert and some limestone. Particles were Table 41—The number of ducks of various species represented by gizzards collected in Illinois in 1938-1940 and the number of these gizzards that contained lead shot pellets, some worn (ingested) and some unworn (embedded). NumBer or | NuMBER OF Number oF Petters SPECIES GIzzARDSs GizzaRDs EXAMINED Wir Sxot Worn | Unworn | Total Mla era la stench in Ge ea eee 2,825 250 404 140 544 MME OBR on 5g Ga) mtosedi 4 i ged aa 881 71 104 42 146 Bena RR Ane Sohne ware 3 160 4 3 3 6 (Cavallo epee tas as OAS ene meee tae 98 2 nets 2 2 DESL GiGi Ae gee eee ee 26 At hits Sap og - arecn-winged teal... :......3..5.-.5: 393 5 66 4 70 Pame-wineed teal: oi.) css y cakes ta ce 129 3 1 2 3 SOW Clete tT Toar paste. cst oe athens, teks 62 SAS es Re ea ee PARC ey nee sh ss sees 28 4 9 atts 9 DDE EN RSet ee eee ee ae 14 2 5 1 6 LIVERS) Cn Aa eae ae en ee 220 43 450 19 469 Memenecked ducks... soi, -.0nh+ ek 120 22 129 ii 148 DMEM Ketek es hh cap nieve u's 208s 11 3 6 6 SSE LOSG NT a ee ei 5 yeh ae ommon goldeneye..:...21.........- 3 PCC RSIVSCHUIN os gout, sled aire Pha vee 1 MN eee, es 1 Serie ET a3 See at” Ree Ma INGLIS i AOS, coh Rady MAO on a pe ae 4,977 409* ILIA 232 1,409 *Of these gizzards, 190 represented ducks in which shot had entered the gizzards at the time the birds were killed. The other 219 represented ducks that had ingested shot. 342 Iuntrnoris Natrurat History Survey BULLETIN measured in millimeters across the widest dimension regardless of tlie shape. ‘1 hese varied from minute to 19 mm. in size; most of them were under 2 mm. Grit in mallard, pintail, ring-necked duck, and lesser scaup gizzards consisted mostly of stones over 9 mm. in size. Baldpate and gadwall gizzards seluom contained gritty material larger than sand particles. Teal and shoveler gizzards seldom contained stones over 2 mm. The frequency with which sand _ oc- curred to the exclusion of stones in the baldpate and gadwall gizzards suggests a relationship between the food habits and physical composition of the grit ingested by these species. Baldpates and gadwalls generally feed on soft, leafy aquatic plants, which are likely to require little or no grinding during the digestive processes, and the sand recovered from the gizzards Vol. 27, Art. 4 of these ducks may have been taken only because it adhered to the food; or it may have been unintentionally taken during normal feeding activity. Shell fragments, rather than stones, were found in the gizzards of many lesser scaups, ring-necked ducks, redheads, gold- eneyes, and shovelers. Many other par- ticles classified as inorganic material were found in the gizzards examined. Fossil fragments of crinoid stems, wood, coral, ‘and brachiopod shells were not uncommon. Muskrat and fish teeth were numerous. Most of these items were rough and angu- lar, serving as excellent grinding agents. LEAD SHOT Lead shot pellets were found in the giz- zards of most of the species of ducks in- cluded in this study, table 41. Some of Table 42.—The number of duck gizzards collected in Illinois in each of 3 years, the num- ber and percentage of these that contained lead shot pellets, and the number of pellets per giz- zard among the gizzards that contained lead. NuMBER NuMBER Per Cent Tora NuMBER OF Ges OF OF OF NuMBER PELLETS PER 5 GizzARDS G1zzARDS GizzARDS OF G1zzarD EXAMINED Wir SxHor Wir SHor PELLETS Wirn SHor 1938. 1,814 159 8 8 998 6.3 1939. 2,291 191 8.3 332 ie? 1940 872 59 6.8 79 1.3 OLB ee 4,977 409* 1,409 *Of these gizzards, 190 represented ducks in which shot had entered the gizzards at the time the birds were killed. The other 219 represented ducks that had ingested shot. Table 43.—The number of duck gizzards collected in Illinois by Dameek periods, 1938-1940, — the number and percentage of these that contained lead shot, and the number of worn (in- gested) pellets per gizzard among the gizzards that contained lead. NuMBER OF NuMBER OF NuMBER OF Per CENT OF NuMBER Worn PERIOD G1zzARDS G1zzARDS G1zzARDS or Worn PeLLets PER EXAMINED Wirn SHor Wirn SHor PELLETS GizzARD Wirtn SHor October 15307 Fe 1,607 89 D5) 84 0 94 November NaS ties ok oe 1,466 101 6.9 297 2.9 November D5 —SO acs sees 1,424 185 13.0 746 4.0 December Er tS eee ena te 480 34 7 fs | 50 1.5 Wola soo aoe 4,977 409* oe 1,177 |. *Of these gizzards, 190 represented ducks in which shot had entered the gizzards at the time the birds were killed. The other 219 represented ducks that had ingested shot. August, 1959 ANDERSON : these pellets had been ingested by ducks in their feeding and some had become lodged in the gizzards at the time the birds were killed. The lining of many gizzards containing lead shot was dark green in color. Any duck from which a gizzard of this color had been taken was considered to have been sick before it was shot. Water levels and firmness of lake or marsh bottoms are among the factors that determine the accessibility and availability of lead shot to waterfowl (Bellrose 1959: 249). Although the percentage of giz- zards containing lead pellets did not vary greatly from year to year for the 3-year period of the study, the average number of pellets per gizzard changed materially, table 42. Probably the lead shot was consumed in the season it was deposited rather than in a subsequent season (Bellrose 1959:266). The gizzard contents showed an increase in percentage of gizzards with lead shot as well as an increase in the number of pel- lets per gizzard as the autumn progressed, table 43. SUMMARY 1. In the autumns of 1938, 1939, and 1940, duck gizzards totaling 4,977 were collected from hunting clubs and _ indi- vidual hunters at 21 sites along the IIli- nois River between Ottawa and Florence and 11 sites along the Mississippi River between Rock Island and Quincy. The following 17 duck species were repre- sented: mallard, pintail, green-winged teal, blue-winged teal, baldpate, gadwall, shoveler, black duck, wood duck, lesser scaup, ring-necked duck, redhead, canvas- back, ruddy duck, greater scaup, common goldeneye, and oldsquaw. 2. Analyses of the gizzard contents were made in accordance with the proce- dure instituted and followed by the U. S. Fish and Wildlife Service, Department of the Interior. Foop Hapsirs or Micratory Ducks 343 3. ‘The analyses indicated that, during the fall, most species of ducks in [Illinois are predominantly vegetarians, that most of them feed principally on native wild plants, and that the lesser scaup is the only species with a diet predominantly animal. 4. Corn made up nearly half of the or- ganic contents of mallard gizzards. Na- tive wild foods were present in relatively greater quantities in gizzards of the wood duck, pintail, redhead, baldpate, green- winged teal, and ring-necked duck, all of which included corn in their diets. 5. Of the 95 wild plants and 4 cul- tivated plants found in the gizzards and identified to species, the following 19 were most important: corn, rice cutgrass, marsh smartweed, coontail, wild millet, longleaf pondweed, red-rooted nut-grass, water- hemp, nodding smartweed, buttonbush, large-seeded smartweed, nut-grass, chufa, Walter’s millet, sago pondweed, duck- potato, river-bulrush, teal grass, and giant bur-reed. 6. The relative positions of the impor- tant food plants changed from year to year as accessibility and availability varied. 7. The importance of a plant species to a species of duck depended on the size of the duck and the type of feeding habitat frequented by the duck. 8. The dabbling ducks fed primarily on emergent and moist-soil plants and the div- ing ducks more frequently on submergent plants. Animal foods were more important to diving ducks than to dabbling ducks. 9. Snails and mussels provided the largest animal food volume and occurred in the largest number of gizzards. Insects were second in volume and occurrence. 10. Grit constituted about 11 to 28 per cent of the gross contents of the gizzards of various duck species. Most of the stones were less than 2 mm. in size; the sizes ranged from minute to 19 mm. in size (largest dimension). 11. More than 200 of the gizzards ex- amined contained lead shot pellets that had been ingested. LITERATURE CITED Bellrose, Frank C. 1938. Abundance and food habits of the waterfowl in the Illinois River valley. Bachelor’s thesis, University of Illinois, Urbana. 33 pp. 1941. Duck food plants of the Illinois River valley. Ill. Nat. Hist. Surv. Bul. 21(8) :237-80. 1959. Lead poisoning as a mortality factor in waterfowl populations. Ill. Nat. Hist. Surv Bul. 27(3) :235-88. Bellrose, Frank C., and Harry G. Anderson 1940. Preliminary report on availability and use of waterfowl food plants in the Illinois River valley. Ill. Nat. Hist. Surv. Biol. Notes 15. 14 pp. Mimeo. 1943. Preferential rating of duck food plants. Ill, Nat. Hist. Surv. Bul. 22(5) :417-33. Cottam, Clarence 1936. Economic ornithology and the correlation of laboratory and field methods. U. S&S, Biol. Surv. Wildlife Leaflet BS-30. 13 pp. Mimeo. Gerstell, Richard 1942. The place of winter feeding in practical wildlife management. Pa. Game Comn. Res. Bili73: cL pp: Fernald, Merritt Lyndon 1950. Gray’s manual of botany. Ed. 8. American Book Company, New York. 1,632 pp. Hawkins, Arthur S., and Frank C. Bellrose : 1939. The duck flight and kill along the Illinois River during the fall of 1938. Am. Wild= life 28(4) :178-86. Hawkins, Arthur S., Frank C. Bellrose, Jr.. and Harry G. Anderson ; 1939. The waterfowl research program in Illinois. Ill. Nat. Hist. Surv. Biol. Notes 12. 16 pp. Mimeo. 4 Low, Jessop B., and Frank C. Bellrose, Jr. 1944. The seed and vegetative yield of waterfowl food plants in the Illinois River valley Jour. Wildlife Mgt. 8(1) : 7-22. Martin, A. C., and F. M. Uhler 1939. Food of game ducks in the United States and Canada. U. S. Dept. Ag. Tech. Bu 634. 156 pp. Nestler, Ralph B. 1946. Mechanical value of grit for bobwhite quail. Jour. Wildlife Mgt. 10(2) :137-42. Wetmore, Alexander 1919. Lead poisoning in waterfowl. U. S. Dept. Ag. Bul. 793. 12 pp. L 344 ] Some Publications of the TLttNois NaTuRAL History SURVEY cM ie BULLETIN Volume 26, Article 3.—Natural Availability of Oak Wilt Inocula. By E. A. Curl. June, 1955. 48 pp., frontis., 22 figs., bibliog. Volume 26, Article 4.—Efficiency and Selec- tivity of Commercial Fishing Devices Used on the Mississippi River. By William C. Starrett and Paul G. Barnickol. July, 1955. 42 pp., frontis., 17 figs., bibliog. Volume 26, Article 5.—Hill Prairies of Illi- nois. By Robert A. Evers. August, 1955. 80 pp., frontis., 28 figs., bibliog. Volume 26, Article 6—Fusarium Disease of Gladiolus: Its Causal Agent. By Junius L. — Forsberg. September, 1955. 57 pp., frontis., 22 figs., bibliog. Volume 27, Article 1.—Ecological Life History of the Warmouth. By R. Weldon Larimore. August, 1957. 84 pp., color frontis., 27 figs., bibliog. Volume 27, Article 2.—A Century of Biological Research. By Harlow B. Mills, George C. Decker, Herbert H. Ross, J. Cedric Carter, George W. Bennett, ‘Thomas G. Scott, James S. Ayars, Ruth R. Warrick, and Bessie B. East. December, 1958. 150 pp., 2 frontis., illus., bibliog. $1.00. Volume 27, Article 3.—Lead Poisoning as a Mortality Factor in Waterfowl Populations. By Frank C. Bellrose. May, 1959. 54 pp., frontis., 9 figs., bibliog. 50 cents, beginning September. CIRCULAR 32.—Pleasure With Plants. By L. R. Tehon. July, 1958. (Fifth printing, with revisions.) 32 pp., frontis., 8 figs. 42.—Bird Dogs in Sport and Conservation. By Ralph E. Yeatter. December, 1948. 64 pp., frontis., 40 figs. 45.—Housing for Wood Ducks. By Frank C. Bellrose. February, 1955. (Second print- ing, with revisions.) 47 pp., illus., bibliog. 46.—Illinois Trees: Their Diseases. By J. Cedric Carter. August, 1955. 99 pp., frontis., 93 figs. Single copies free to IIli- nois residents; 25 cents to others. 47.—Illinois Trees and Shrubs: Their Insect Enemies. By L. L. English. May, 1958. 92 pp., frontis., 59 figs., index. Single copies free to Illinois residents; 25 cents to others. List of available publications mailed on request. Single copies of ILt1no1is NATURAL History SuRvEY publications for which no price is li will be furnished free of charge to individuals until the supply becomes low, after which More than one copy of any free publication may be obtai without cost by educational institutions and official organizations within the State of Illin prices to others on quantity orders of these publications will be quoted upon request. . nominal charge may be made. Address orders and correspondence to the Chief, ILLINOIS NATURAL History Survey, Natural Resources Building, Urbana, Illinois — Payment in the form of money order or check made out to State Treasurer of Illir BIOLOGICAL NOTES 29.—An Inventory of the Fishes of Jordan Creek, Vermilion County, Illinois. By F Weldon Larimore, Quentin H. Pickerin ig, : and Leonard Durham. August, 1952. 26 pp., 25 figs., bibliog. 30.—Sport Fishing at Lake Chaotanaiae near Havana, Illinois, in 1950 and 1951. By William C. Starrett and Perl L. McNeil, Jr. August, 1952. 31 pp., 22 figs., pert! i 31—Some Conservation Problems of — Great Lakes. By Harlow B. Mills. Octori ber, 1953. (Second printing.) 14 PP, its bibliog. i R 33.—A New Technique in Control oft the 2 House Fly. By Willis N. Bruce. D ‘4 ber, 1953. 8 pp., 5 figs. 34,—White-Tailed Deer Populations in nois. By Lysle R. Pietsch. June, 1954, pp., 17 figs., bibliog. 35.—An Evaluation of the Red rune Thomas G. Scott. July, 1955. (Second printing.) 16 pp., illus., bibliog. 36—A Spectacular Waterfowl Migratis 4 Through Central North America. By Fra C. Bellrose. April, 1957. 24 pp. 9 f bibliog. 37.—Continuous Mass Rearing of the Ei pean Corn Borer in the Laboratory. Paul Surany. May, 1957. 12 pp. 7 bibliog. 38.—Ectoparasites of the Cottontail Rabbi Lee County, Northern Illinois. By Lewi Stannard, Jr., and Lysle R. Pietsch. Ji 1958. 20 pp., 14 figs., bibliog. 39—A Guide to Aging of Pheasant Embr By Ronald F. Labisky and James F. Ops: September, 1958. 4 pp., illus., bibliog, 40.—Night-Lighting: A Pochiaae for C turing Birds and Mammals. By Ronald Labisky. July, 1959. 12 pp., 8 figs., bibl MANUAL | 3.—Fieldbook of Native Illinois Shrubs. Leo R. Tehon. December, 1942. 307. 4 color pls., 72 figs., glossary, index. $1 4.—Fieldbook of Illinois Mammals. By Don F. Hoffmeister and Carl O. Mohr. Jr 1957. 233 pp., color frontis., 119 figs., g sary, bibliog., index. $1.75. Springfield, Illinois, must accompany requests for those publications on which a price is s¢ ILLINOIS NATURAL HISTORY SURVEY Bulle tin Printed by Authority of is ig Y the State of Illinois WB: Hook-and-Line Catch in Fertilized and Unfertilized Ponds DONALD F. HANSEN GEORGE W. BENNETT ROBERT J. WEBB JOHN M. LEWIS STATE OF ILLINOIS @ Wham G. Srratron, Governor } DEPARTMENT OF REGISTRATION AND EDUCATION @® Vera M. Binks, Director NATURAL HISTORY SURVEY DIVISION ® Harvow B. Mus, Chief ; ILLINOIS NATURAL HISTORY SURVEY Bulletin Volume 27, Article 5 Saas Printed by Authority of August, 1960 the State of Illinois Hook-and-Line Catch in Fertilized and Unfertilized Ponds DONALD F. HANSEN eEORGE W. BENNETT ROBERT J. WEBB JOHN M. LEWIS STATE OF ILLINOIS e@ WrtiAm G. STRATTON, Governor DEPARTMENT OF REGISTRATION AND EDUCATION ©@® Vera M. Binks, Director NATURAL HISTORY SURVEY DIVISION © MHartow B. Mitts, Chief Urbana Illinois STATE OF ILLINOIS Wintiam G. Strarron, Governor DEPARTMENT OF REGISTRATION AND EDUCATION Vera M. Binks, Director BOARD OF NATURAL RESOURCES AND CONSERVATION Vera M. Binxs, Chairman; A. E. Emerson, Ph.D., Biology; Watter H. Newnouse, Ph.D., Geology; Rocer Apams, Ph.D., D.Sc., Chemistry; Rornert H. Anverson, B.S.C.E., Engineering; W. L. Everitt, E.E., Ph.D., Representing the President of the University of Illinois; Detyre W. Morris, Ph.D., President of Southern Illinois University NATURAL HISTORY SURVEY DIVISION, Urbana, Illinois SCIENTIFIC AND TECHNICAL STAFF Hartow B. Mitts, Ph.D., Chief Bessie B. East, M.S., Assistant to the Chief Section of Economic Entomology Grorce C. Decker, Ph.D., Principal Scientist and Head J. H. Biccer, M.S., Entomologist L. L. Enouisu, Ph.D., Entomologist W. H. Lucxmann, Ph.D., Entomologist Wiiuis N. Bruce, Ph.D., Associate Entomologist Joun P. Kramer, Ph.D., Associate Entomologist Ronatp H. Meyer, M.S., Assistant Entomologist Ricuarp B. Dysart, B.S., Assistant Entomologist Eucene M. Bravi, M.S., Research Assistant Roy E. McLaucuuin, B.S., Research Assistant RecinaLtp Roserrs, A.B., Technical Assistant James W. Sanrorp, B.S., Technical Assistant Fart STADELRBACHER, B.S., Technical Assistant Wittiam C. Moye, M.S., Technical Assistant sue FE. Warxins, Technical Assistant H. B. Perry, Ph.D., Extension Specialist in Entomology* Stevenson Moore, III, Ph.D., Extension Specialist in Entomology* Zenas B. Noon. Ir., M. S., Research Assistant* Crarence FE. Wuire, B.S., Instructor in Entomology Extension* Cosras KousxorexKas, M.S., Research Assistant* Amat CuHanpra Banerjee, M.S., Research Assistant* Section of Faunistic Surveys and Insect Identification H. H. Ross, Ph.D., Systematic Entomologist and Head Mirron W. Sanverson, Ph.D.. Taxonomist Lewis J. Srannarp, Jr., Ph.D., Associate Taxonomist Puitie W. Smirn, Ph.D., Associate Taxonomist Leonora K. Groyp, M.S., Assistant Taxonomist H. B. Cunnincuam, M.S., Assistant Taxonomist Epwarp L. Mockrorp, M.S., Technical Assistant Tuetma H. Overstreet, Technical Assistant Toun M. Kincsorver, M.S., Research Assistant Taraat K. Mirri, M.S., Research Assistant* Section of Aquatic Biology Georce W. Bennett, Ph.D., Aquatic Biologist and Head Wittiam C. Starrett, Ph.D., Aquatic Biologist R. W. Larimore, Ph.D., Aquatic Biologist Davin H. Bucx, Ph.D., Associate Aquatic Biologist Roserr C. Hintisran. Ph.D., Associate Biochemist Donatp F. Hansen, Ph.D., Associate Aquatic Biologist Witiiam F. Cuinpers, M.S., Assistant Aquatic Biologist Marirran Martin, Technical Assistant Ronert D. Crompton, Field Assistant Larry S. Goopwin, Laboratory Assistant Arnotp W. Frirz, B.S., Field Assistant* Section of Aquatic Biology—continued Daviv J. McGinty, Field Assistant* Cuarutes F. Tuorrts, III, A.B., Field Assistant* Section of Applied Botany and Plant Pathology J. Cepric Carter, Ph.D., Plant Pathologist and Head J. L. Forssperc, Ph.D., Plant Pathologist G. H. Boewe, M.S., Associate Plant Pathologist Rosert A. Evers, Ph.D., Associate Botanist Rosert Dan Nee ty, Ph.D., Associate Plant Pathologist E. B. Himenicx, Ph.D., Associate Plant Pathologist Water Harrstirn, Ph.D., Assistant Plant Pathologist D. F. Scuorenewerss, Ph.D., Assistant Plant Pathologist Heriey C. Tuompson, B.S., Research Assistant Section of Wildlife Research Tuomas G. Scorr, Ph.V., Game Specialist and Head Rarpew E, Yearter, Ph.D., Game Specialist Cart O. Monr, Ph.D., Game Specialist F. C. Beturose, B.S., Game Specialist H. C. Hanson, Ph.D., Associate Game Specialist Ricuarp R. Graser, Ph.D., Associate Wildlife Specialist Ronatp F. Lasisxy, M.S., Assistant Wildlife Specialist Marjorie J. ScuiattTer, J'echnical Assistant Howarpv Crum, Jr., Field Assistant Joun L. Roseperry, B.S., Technical Assistant Rexroxpv D. Lorp, D.Sc., Project Leader* Freperick GREELEY, Ph.D., Project Leader* Guten C. Sanpverson, M.A., Project Leader* Rosert I. Smiru, M.S., Project Leader* Jacx A. Exuis, M.S., Assistant Project Leader* Witiiam L, Anpverson, B.S., Assistant Project Leader* Tuomas R. B. Barr, M.V.Sc., M.R.C.V.S, Research Assistant* Bosnie Jor Verts, M.S., Field Mammalogist* Frwin W. Pearson, M.S.. Field Mammalogist* Ricuarp D. Anprews, M.S., Field Mammalogist* Kerry P. Daupnin, Assistant Laboratory Attendant* Section of Publications and Public Relations James S. Ayars, B.S., Technical Editor and Head BuancHe P. Younc, B.A., Assistant Technical Editor Wituiam E. Crark, Assistant Technical Photographer Marcurrite Verey, B.A., Technical Assistant Technical Library Rutw R. Warrick, B.S., B.S.L.S., Nrit Mires, M.S., B.S.L.S. Librarian : Technical Librarian , Assistant Technical CONSULTANTS: Herrerotocy, Hosart M. Smiru, Ph.D., Professor of Zoology, University of Illinois; Parasirouocy, Norman D. Levine, Ph.D., Professor of Veterinary Parasitology and of Veterinary Research, University of Illinois ; Wirptire Researcu, Witrarv D. Kuimsrra, Ph.D., Professor of Zoology and Director of Co-operative Wildlife Research, Southern Illinois University. _ “Employed on co-operative projects with one of several agencies: University of Illinois, Illinois Agricultural — Extension Service, Illinois Department of Conservation, United States Army Surgeon General’s Office, United States Department of Agriculture, United States Fish and Wildlife Service, United States Public Health Service, and others. This paper is a contribution from the Section of Aquatic Biology. (16668—6M—5-60) aggro 2 CHOW FEIN TS SMMBRIMERICNOWES ES OG. Safe 205 oO fine ate y ciel edna Gt at Ae ts aga biale Melee Sed Ue 345 DBERINMENTAL PONDS AND [HEIR WATERSHEDS. ...... 5... ..0.0c0c0ccceeeaecdenu 346 RUINED a ROCKIALRES.Y sais hand-nl'o.Slx 05.0 Gis''s videFir ola bin DOS cin vos Oe ree wees Pe Segoe 493 EAM PRET Ce OOS Ay, eek: co eh ATPases leds hb GaSe | a Aaa eee Se aw eae oe 353 SHED a HAE ear EMI CLS eos yc custom lacs AOR (oieie le im pees esl e wal sacks ee Gk idee Ae 354 MRE EGS SIRO TED AL Ate 40M Ae facie Obs AE ALA wee? Laklacnm apa ace omer 355 reteset OE eat Hii she OPILALIGIIS 2. & fos o: 224d ja eles nye Sos aim vide ene de eee med eee 356 OR ERELZA TION AND) PANT IOERE. 6% cola devs 2 evils ew gccte nid a vibe oes ave 4 nyalola wi aaah 356 RAMEE TMIZATION AND FISHING SUCCESS. |. 0. 2.5 < sec e006 Sie ae suclee ele eda ee nes eee 358 CT ee PE DESI S22 1 ed a a eens Cid ee age PR oe ee ES AOI ee cone ns fr 361 Amimall Blog kecin@el bitin SGiahiioe. aac nena oes ere ots 5 Gino Garo oneal ia nee 363 ea MS ee ed te eta eines Sd Sain Ae ae CS Os ea Oo eae 365 Barchelates tor, hishy What: Were: Harvested: 2.002026 wick Sos as ee es 367 Rieter Swi Ce ATRIA CALE Sie Ao ie oes « 'o Alotorerceaelshs cumin aaoetard a nae Sea Spero eS Pisin bressureswanes Gatch ILAteS .,. osteo ni ad-aw-c. cheeisae dle weitied-o OF sie ght adhe 375 HecHiliation RALeS Ang, Catch IN AECS 3 cnc omia soso vioan dees ee eee Gases aaa 375 SPERM LIZATION AND STANDING GROPS. «s-:04 os c- b onlay oa oe ola cote oe bse ee 376 PE OROPS CAND WP ISEIING DUCCESS: 2.060 ved. be uence ree beee cease estan eeuee 380 MELERTILIZATION AND FISHING SUCCESS. 0.05525 0600 ed beac nee nent eenes ec deenc 383 MONIES OLB EO NDS ER TTOIZAMION = cuss eyo ciess ss oes siesate laos eee oenvie ean Se eisecce eke 385 Pee CAL UATIONCOR LONDS 5 o<..0+ «osc sor se cute ok oe eS elaine see acct tects Oe acts 386 ERICA UE Sve hae he eS OARS lanchtvs whic eran he ant aR eS oe 387 “react umn (CONTITSIB 2 eee 2 Se re oe ee Oe, ne a A ME Pt Oar Oa ieee Rate 389 NA. et Pr LY, a ; Ce tee ‘ > es ence at’ Hook-and-Line Catch in Fertilized and Unfertilized Ponds XPERIMENTS carried on in the | eae States during the past 30 years have shown that the total weight of fish in a pond, that is, the stand- ing crop, may be increased two to six times through the use of fertilizers (Davis & Wiebe 1931; Smith & Swingle 1939; Smith & Moyle 1945; Surber 1945, 19484; Swingle 1947; Ball 1949; Ball & Tait 1952). These experiments have quite naturally led to the speculation that fertilization is a means of improving hook-and-line fish- ing. While the practice of fertilizing ponds has been widely recommended to pond owners, few attempts have been made to measure the effect of fertilization on angling results. In published studies of angling in ponds (King 1943; Swingle 1945; Smith 1952, 1954) results have been inconclusive with respect to the effect of fertilization on catch of fish per hour. Studies of the effects of fertilization on aquatic plant life, on animals eaten by fish, and on fish crops have been reviewed by Neess (1949), Maciolek (1954), and Mortimer & Hickling (1954). The objective of the pond fertilization experiment reported in this paper was to measure the effect of certain fertilization practices on sport fishing for largemouth bass, Micropterus salmoides (Lacépéde), and bluegills, Lepomis macrochirus Rafin- esque, in small ponds located in a region of relatively unproductive soils. From catch records gathered over a 6-year pe- riod, 1947-1952, from three fertilized ponds and three unfertilized or control ponds, we have been able to compare the sizes of the fish caught, the annual hook- -and-line yields, and the catch rates in terms of fish per fisherman-hour. The six ponds used in the experiment are lo- *Robert J. Webb is Superintendent and John M. Lewis is Assistant Superintendent of the University of Illinois College of Agriculture Dixon Springs Experiment Station. DONALD HAN SEN GEORGE AW. BE N Nie ROB ORT Al vO Ene JORLN: Oc LEW ES cated at the University of Illinois College of Agriculture Dixon Springs Experi- ment Station in Pope County, southern Illinois. The methods of stocking and fertilizing were, in part, variations of those first pro- posed by Swingle & Smith (1941: 224-5, 1942:12-3, 16-8). Recommendations of Swingle & Smith for minimum fertiliza- tion were followed closely during the last 2 years of the 6-year study. A census of the fish population of each of the ponds was made in the fall of 1953. In the census operations all fish in the ponds were killed with rotenone so that we were able to compare standing crops of fishes in the ponds that had been treated with fertilizer for an extended period (7 years) with the standing crops in the ponds that had not been treated with fertilizer. In addition, we were able to compare the standing crop of fishes in each pond with the hook-and-line fish vields and catch rates recorded during the last 3 years of angling. Published data on angling success in ponds stocked with only largemouth bass and bluegills are scarce. The present study demonstrates the value of this pop- ular combination of fishes, as well as the effect of fertilization, in southern []linois ponds. ACKNOWLEDGMENTS Information on soils and soil treatments at the Dixon Springs Experiment Station was furnished by C. A. Van Doren of the United States Soil Conservation Serv- ice and by the following persons from the University of Illinois College of Agricul- ture: W. G. Kammlade, Leah M. Dunn, George E. McKibben, and Leland E. Gard. The following persons, all with the College of Agriculture, were con- sulted on general questions pertaining to soils and soil fertility: A. L. Lang, [ 345 ] 346 Ittinors NAtuRAL History SurvEY BULLETIN Lawrence B. Miller, Roger H. Bray, Russell T. Odell, Herman L. Wascher, J. B. Fehrenbacher, and the late Robert F. Fuelleman. H. W. Norton, Professor of Agricultural Statistical Design and Analysis, Animal Science Department, has examined the data and has verified certain conclusions reached in this study. Water samples from the experimental ponds were analyzed by T. E. Larson of the Illinois Water Survey. Fishing boats were provided by the Illinois Department of Conservation through the courtesy of Sam A. Parr, formerly Superintendent of the Division of Fisheries, now Admin- istrative Assistant. Help with fertilizing the ponds or with the rotenone census was given by R. Weldon Larimore, William N. Nuess, Robert Crompton, and the late Dan Avery, employed by the Illinois Nat- ural History Survey, and by Ray Brown, Guy Bellamy, Leonard Durham, and Oliver Dick, employed by the Department of Conservation. Charles Stubbs in 1947, Maurice G. Kellogg in 1948, 1949, and 1950, Stacy Gebhards in 1951, and Charles R. Peters in 1952 served as test anglers. The pho- tograph for the frontispiece and the aerial photographs were made by Charles Scott, formerly employed by the Illinois Natural History Survey and now picture editor of the Milwaukee Journal. The other pho- tograph was taken by George W. Ben- nett. The manuscript was read by Wil- liam C. Starrett and edited by James S. Ayars and Mrs. Diana R. Braverman, all of the Illinois Natural History Survey staff. EXPERIMENTAL PONDS AND THEIR WATERSHEDS The ponds selected for use in this ex- periment—Lauderdale, Hooker, Phelps, Wells, Boaz, and Elam, figs. 1-6—are stock-watering ponds built at the Dixon Springs Experiment Station in the period 1935-1940. All have earthen dams. All are fenced and, during the years of the experiment, cattle seldom had access to them. They are all within a 2-mile radius of the Experiment Station headquarters. In September, 1951, at a time when these ponds were full of water, thev ranged in surface area from 0.92 to 1.55 Vol. 27, Art. 5 acres, and from 8.5 to 15.0 feet in maxi- mum depth, table 1. Since the only source of water for the ponds was surface run- off, there was always a reduction in water area and in depth during dry weather of late summer. Presumably these water level reductions varied in the six ponds in accordance with relative size of drainage areas, number of domestic animals using the water, shape of the pond basins, and rates of runoff, evaporation, and under- ground seepage. In the fall of 1953, after one of the driest summers on record, the reduction in surface area of the various ponds ranged from 13 per cent in one pond to 49 per cent in another, table 1. There was little difference between the late summer levels of 1953 and those of 1952, another dry year. We have esti- mated from general observations that late summer water levels in 1952 and 1953 were | to 2 feet lower than those of most other years represented in this study. Al- though in 1953 Wells Pond showed the greatest reduction in surface area, in most years Phelps Pond showed the greatest reduction. The test anglers made weekly measure- ments of surface water temperatures through the summers of 1947 and 1948. Temperatures above 90 degrees F. were rarely encountered in the series of weekly readings. The maximum surface tempera- ture reading at any of the ponds was 94+ degrees, observed at Boaz Pond, first on July 29 and again on August 5, 1947, and at Phelps Pond on July 12, 1948. ‘Temperature measurements made at 2- foot depth intervals on August 12, 13, and 14, 1947, table 2, showed marked thermal stratification in five of the six ponds. Chemical analyses of water from the ponds, table 3, were made from samples collected March 19, 1947, before the fertilization experiment was begun. The watersheds of all of these ponds had been fertilized prior to the time the water an- alyses were made, but Lauderdale Pond was the only one that had received direct fertilization. Before the experiment re- ported here was planned, this pond had been treated on two occasions in an at- tempt to improve fishing: on August 17, 1945, with 80 pounds of ammonium sul- fate, 32 pounds of 63 per cent superphos- — August, 1960 HANSEN et al.: HooK-AND-LINE CaTCH 347 Fig. 1.—Aerial view of Lauderdale Pond, 0.9 acre, October, 1950. The fields on two sides of the pond had been plowed and reseeded a few weeks before the picture was made. Fig. 2—Aerial view of Hooker Pond, 1.33 acres, October, 1950. 348 Intrnors NaturRAL History SurveEY BULLETIN Vol. 27, Art. 5 Table 1.—Depth and area of each of the six Dixon Springs ponds used in fertilization study, as observed at full stage in September, 1951, and at the time of the rotenone census, September, 1953. The levels observed in 1953 were probably as low as or lower than any levels that occurred during the fishing period. Lowest OBSERVED | gEuusmor. | 'Brovowr Seige ? SEPTEMBER, 1953 REDUCTION Ponp ane In AREA, Depth Area Depth Area Per CENT in Feet in Acres in Feet in Acres FERTILIZED | Lauderdale... =..0c0 ee 1 0.92 9.8 0.76 17 Hookeriscc 200 ees ee 14.0 1.33 10.6 1.03 23 Pee. Gir cide ete heres cee 8.5 1.04 4.5 0.70 33 UNFERTILIZED Wellgo ice a eel 15.0 0.97 12.0 0.49 49 15 OE vt panes rah ga Oe Hl Sane 10.5 1.01 6.8 0.66 35 Elam ae 9.0 £255 6.8 135 13 phate, and 25 pounds of ground lime- stone; and on September 8, 1945, with 80 pounds of ammonium sulfate, 100 pounds of 20 per cent superphosphate, and 25 pounds of ground limestone. An unusual characteristic of the Dixon Springs ponds was their relatively low total hardness; according to T. E. Larson, Illinois Water Survey, these waters are among the softest surface waters in IIli- nois. Under the crop rotation systems fol- lowed by University of Illinois agron- omists at the Dixon Springs Experiment Station, the fields surrounding the ponds were kept in pasture most of the time. New rotations were begun on the water- shed of each of these ponds within the Table 2.—Water temperature (in degrees F.) measured at 2-foot intervals and on bottom period of the study: Phelps in 1948, Hooker in 1949, Wells and Lauderdale in 1950, Boaz (east half) in 1949, Boaz (west half) in 1951, and Elam in 1952. In each pasture reseeding, winter wheat or rye was planted with various grasses in the fall of the year, while legumes were broadcast the following spring. Corn was planted in the spring prior to the fall seeding on the Boaz west field in 1951 and on the Elam watershed in 1952. Until dense pasture growth was re- established, silt from the fields was washed into the ponds after each hard rain. Silting occurred even though grass buffer strips surrounded the ponds. The Dixon Springs Experiment Station lies in an unglaciated region where the in the six Dixon Springs ponds, August 12-14, 1947. | LAUDERDALE Hooker PHELPS WELLS Boaz ELam DEPTH IN (DeptTH 8 (DeptuH 10 (DeptuH 5 (DeptH 10 | (Depro 84%) (DepTH 6 Feet Feet)* FeeET)* FeeT)* Feer)* Feet)* Feet)* Avucust 12 | Aucust 12 | Aucust 13 | Aucusr 12 | Aucust 13 | Aucust 14 Surface....... 89.2 558 ode ees 87.1.5 |e Beee 83.1 LP Saki SE fe ae 84.6 83.1 83.1 85.6 82.0 83.1 is aan eee ey 83.1 82.8 81.7 84.9 Var 84.24 pe eee TET SOEG: ics eer 75.6 66.9 82.4 ee ae 72.0 p57 Mario Wi Peete eer a Ves 64.8 ol) Bottom...... 72.0 68.0 78.4 68.7 64.4 82.4 ——e ee *Depth of water at point of temperature readings, not necessarily the greatest depth in the pond at the time. The — bottom reading is for this depth. reading for Hooker is for a depth of 10 feet. 7This figure probably represents an error in recording. Examples: The bottom reading for Lauderdale is for a depth of 8 feet; the bottom August, 1960 HANSEN et al.: Hook-ANp-LiINE CATCH 71g. 3.—Aerial view of Phelps Pond, 1.04 acres, October, 1950. Exposed mud flats resulting from loss of water may be seen around the margin of the pond. Fig. 4.— Aerial view of Wells Pond, 0.97 acre, October, 1950. The cypress trees in the water and the pines in the fenced area surrounding the pond had been planted. 350 I-ttinois NaturAL History SurveEY BULLETIN Vol. 27, Art. 5 Table 3.—Mineral composition (parts per million) of water collected from the six Dixon Springs ponds on March 19, 1947, prior to fertilization. MINERAL povaeen Hooker* | PHELPs* WELLS Boaz ELam Iron—filtered............. 0.3 0.3 0.6 0.3 bey 0.7 Iron—unfiltered...........| 0.6 0.4 ily a! 0.5 2.8 1.0 Phosphate fai Ui gaa stuart Or? Oz 0.2 0.3 0.8 0.6 Galcivuin dna see eee 8.1 6.0 8.8 6.6 7.0 7.6 Mapheetti occ oe nn bee oi L3 0.2 0.4 0.0 0.0 0.0 Sodium and potassium..... 1.8 4.6 0.0 0.9 4.4 3.4 Sulfate ss cievc node law UE? 10.5 8.2 7.0 12.3 10.1 Nitrate rd. fia tts Sates ae 1.0 0.4 0.5 0.5 2.0 0.8 Ghloridess2. ues eae 1.0 5.0 2.0 2.0 3.0 3.0 Methyl orange alkalinity... 16.0 8.0 12.4 8.0 9.0 12.0 Totaljhardnessiae sates 26.0 16.0 24.0 16.0 18.0 19.0 *Pond selected for fertilization. ‘ +As orthophosphate PO, (includes organic phosphorus). tIncludes N in the form of ammonia and nitrate but not in the form of nitrite or as organic nitrogen, terrain is a mixture of gently rolling land and steep hills. Numerous sandstone out- crops are present. The region was com- pletely forested at the time of settlement, and considerable woodland still exists. During the many decades in which the cleared land was used extensively for growing corn and wheat, most of the slopes suffered from erosion. With the re- cent trend toward permanent pastures or crop rotations that include pasture, the rate of erosion on slopes has been greatly retarded. The level of productivity of a fish pond and its capacity for providing good fishing are generally assumed to be determined to a great extent by the level of plant nu- trients in the soils of the pond bottom and of the watershed. In common with soils over most of Pope County, those at the Experiment Station have low natural fer- tility. Recent tests of soils in Pope and Hardin counties showed 96 per cent of the samples deficient in available phos- phorus (Thor & Jacob 1955). The soils on the watersheds of the ponds used in the pond fertilization study belong to two soil types. Grantsburg silt loam covers the hilltops and lesser slopes, and Manitou silt loam covers the steeper slopes ( Fehren- bacher 1959). These soil types, which are closely re- lated, are described by Fehrenbacher (1959) as grayish yellow or brownish Table 4.—Available phosphorus and potassium (as pounds per acre in the upper 6 2/3 inches of soil) and the pH of soils of the fields draining into four of the six Dixon Springs ponds. The ratings, such as “high,” are based on a system used by the University of Illinois Soil Testing Laboratory. one or| Most Recent YEAR Pounps Per Acre COND oF Soi, TREATMENT Date or SoiL S : ai H WaTeER- | PrecepinG Soi Test* as eae Available Available P SHED Phosphorus | Potassium Phelps... . 1948 January 6, 1957 66 ae 187 (High) 6.3 to high) Wells..... 1952 February 10, 1956 84 (High) 110 (Slight) 6.2 Boazt.....| 1936 August 14, 1951 10 (Very | 265 (Very 6.0 low) high) Flam) sc 1952t August 8, 1952 rad ais 95 (Slight) 559 ow) *Kinds and amounts of fertilizer materials used are shown in table 5. +The soil test was made on the west half of the Boaz watershed. Spring. August, 1960 HANSEN et al.: HooK-AND-LINE CaTCcH 351 Fig. 6.—Aerial view of Elam Pond, 1.55 acres, October, 1950. 352 gray silt loams, which, if untreated, are strongly acid, low to very low in avail- able phosphorus, low to medium in avail- able potassium, and low in organic mat- ter. University of Illinois agronomists have found that in order to farm these soils at a profit it is generally necessary to treat them with crushed limestone and with either rock phosphate or superphos- phate. They have also found that it may be profitable to use complete fertilizers on seed beds and as top dressing on poorly growing pastures. Iturnoris NaturAL History SurveEY BULLETIN Vol..27;. Art. 5 Soil tests were available for the fields draining into four of the six experimental ponds, table +; tests were not available for the other two fields. The fact that the soil tests on these fields show only slight acidity and that some of them show high amounts of available phosphorus and po- tassium is explained by the soil treatments made in connection with field crop studies. applied in the period 1935-1953 to the fields draining into the six ponds. Prior to the soil tests recorded in table 4, all of . Table 5.—Soil treatment dates and materials (in pounds per acre) applied to the fields draining into the six Dixon Springs ponds. The east and west halves of Hooker and Boaz watersheds were treated separately. The manner of treatment, where known, is indicated by a letter.* The watershed area indicated for each pond includes pasture but not woodland. J | i Table 5 is a record of all soil treatments | | —— SEE SUPERPHOSPHATE | £ mn Compcere Ferrinizer | : 3 = >a oder z WaTERSHED Date OF Pi ee oe as Z |, sa NAME AND SoIL S rs 3V | 00 ou vo oO - = : AREA TREATMENT S 75a a ©) a 2 = Ph pate ae o “a 3 | 4f|2|818|gelzel a | Geo & eae om | | $0 | PO] = = a oo & 4 a me el Gand cee abs a | | an | o | Rae Lauderdale, {1937 SQO0THIESS -ealesee 200 9)... ve ete |. nee oD ee ; 5 acres 1950 (fall)t 6, 000M|12000M100 BD) .pan4\oue oc lect Gs acral eis eee 180 ||... 5.3) O52 iGsyoranne) holy, asst oli agaoe ec [ees oe | eel ees (NCO TO) Bal fe retire toed: 100T |... | =e (oe € 2 Ds Be ee eg er RIO CAL 8 SSN BE | Ae LOOM | easier LOOT: | 2°S5\20 eee F 1953 (eprint raileccar meal Boer aero 15 OMe Been 1S0T |). .:..|).5) sel : Hooker, 1935 8,000T |... -.c)ceeus|ee cs -|egee chess melee cache. colo neal ae : east half, {1949 (fall)t [8;000M|1,000M|.....|.....].....].....|...--[o...0le oso elfen nnn 9=10: Bete L953 KSPHANB) es xcs oen shia owl ee ose ae eal ee nT es eee ie aa 200T |... s.\0 | IncHEs* 1947/1948 1949 1950)1951)1952|1947/1948)1949|1950)1951|1952/1947|1948)1949|1950)1951,1952 vn o — — et —_ — _ tw NrWwWhH = Ww in — RNR Roe o mWnIOnNI OO NWN = mr he SI I NN Nee — er OO en to ni nn in aAnhe Teen NU —_ DEKH NOO oppoa-— DP ~100W WROD nn i) PrmWOL Lhe — RNR POW RD Ww _— — nN ANDDWUNN —e— pe ee —_ Nr KSNN RRR hee —_— _— _ w& o Nw RNR WON NN — tt — wn nn _ Total.) 5%: 15 | 50 | 44 | 20 | 19 | 22 | 91 12 | 30 | 34|-16 | 13 | 8 | 43 | 71) 50) 360m class or laren. |) boo) lt See? e| 16 eel 8 4 Daal. 7 9 8 5 9 | 18 | 20 |e Average length of fish 10-inch class or larger . .|11.1/12.4/11.2/11.2/11.7/12.1/10.6/13.0]10.3/11.0/11.2/11.3]11.0/11.5/11.9/10.6]10.7|11.8 Per cent in 10- inch class or larger ..| 100} 22 | 34 | 60 | 84 | 77 | 89 | 33 7 | 35 | 44 | 69 |100 | 12 | 13 | 36 | 56 | 57 *Each number designating inches represents the mid-point in a length class; for example, the number 5.0 includes the bass of 4.8-5.2 inches total length. August, 1960 Boaz, and Elam, with respect to the sizes of fish caught, the annual fish yields, and the catches per fisherman-hour. Sizes of Fish Caught Length distributions of all bass and all bluegills caught by the test anglers are shown for the six ponds in tables 9, 10, 12, and 13; these tabulations include the HANSEN et al.: HooK-AND-LINE CatcH 361 bass under 10 inches and the bluegills un- der 6 inches that were put back in the ponds after measurement. The average weights of fish caught and kept by test anglers and permit fishermen are shown in tables 11 and 14; lengths of fish caught by permit fishermen were not recorded. Few of the bass caught by test anglers measured more than 13 inches; the only Table 11.—Average weights (in pounds) of individual largemouth bass harvested by hook and line from each of the Dixon Springs ponds in each of 6 years. Data from which the figures were derived are in table 20. Ponp 1947 1948 1949 1950 1951 1952 AVERAGE FERTILIZED Lauderdale. ... 0.60 0.71 ()sSi7/ 0.68 0.83 0.70 0.68 looker... .... 0.63* O72} 0.63 0.60 0.63 0.53 0.62 Phelips® 4: <-- 0.50* 0.43 0.50* 0.53 0.71 0.75 0.57 eerste mT ed a Tec (ce7aTS 5) Foc |. 0 Sra se theta pea amet ReR ES ls ts iw eee simvocen eae er Retr = 0.62 UNFERTILIZED Wellse 2 oles: OF73 0.92 0.63 OE 7Al 0.68 0.92 OL77 Boaz 0.67* il aails} 0.57 0.58 0.64 0.83 0.74 [EIGN Rare ene 0.63* 0.64 0.91 0.64 0.72 0.74 0.71 JECTED 0, 0 6 3,04 OND SOB OM |e Cae eee ee | RRR 7 bl eric nena Pe (earn teres co | Gitano 0.74 *Average based on fewer than 10 specimens, as shown in table 20. Table 12.—Numbers of bluegills, in various length classes, caught by Illinois Natural History Survey test anglers in three fertilized ponds at Dixon Springs. Bluegills of less than 6 inches in length were returned to the water. LAUDERDALE Hooker PHELPS LencTH Crass, INcHEs* ae 1948|1949 1950,1951,1952)1948 1949 1950 1951/1952 1948 19491950 1951 1952 0). seo RE ee eee Spr Be alii L3.cosge eee eee iyi: 1 eee ae 1 ae bore (Pe Dies ee 10: ie ree 1 he sce Dee lnc ea he 1 1 a (e ieee A | 6 Scot ee (WC A751 SiS) TS) ee AS eae el el ce Tie as _ |e SAS Po J gis 5 ll! 4 pA ailing? | RIES in! og 1 er ee 5 0 RES ee Gi By 27) 9 AA. Gln ed 2 ee |e eet | Le cs eee eee 19 9; 40 5 6 1 2 Zl 4 2 2 g 3) 10] 16 ee Ga tat 27) 16) “19 Fi Si MONS 2a te ee SS 2 ts ” (0), oct Been ee sae 2025) 17) 30) 43" 19 5 Sie Lie 20a! 4) 12 8 ee MG ole SS| 37), 40) 6 Si 91 ellie <4 heer. AED Ae A 47, ao OS is tA 22 | 22 ee Sle Si yee set. Ni Se 4) |. See ee OR | lta 11) Vas YE (ae SS Pcie Crees) ea ares Lets ocd oe cecil tetanre Lie 23 aval, do See 112| 74| 180\ 133) 143| 32| 37) 47) 63 CN Si7Al (ssl! S15 = BON 740) Number in 6-inch class Of EES erate eee 100} 68] 132} 121] 135} 30) 27) 32) 59 Al 25) 60|" es)? e oi Average length of fish, 6-inch class or larger...| 6.5] 6.9] 6.8| 7.4] 7.3] 6.9] 7.3) 6.9) 6.8] 6.4) 7.0) 6.9| 7.2) 6.8) 6.9 Per cent in 6-inch class O? [Eig aan as See 89| 92] 73} 91} 94| 94) 73} 68] 94) 44) 76). 92) 51} 94) 67 *Each number designating inches represents the mid-point in a length class; for example, the number 4.0 includes the bluegills of 3.8—4.2 inches total length. 362 ones over 16 inches were caught in a fertilized pond, Lauderdale. The bass of 10 inches or longer taken by the test anglers from fertilized ponds, table 9, were smaller on an average than those from the control ponds, table 10; those from the three fertilized ponds averaged 11.5, 10.5, and 10.8 inches; those from the three control ponds averaged 11.6, 11.2, and 11.3 inches. The individual Ittrnors NarurAL History Survey BULLETIN Vol. 27, Art. 5 bass harvested by test anglers and permit —* fishermen from the control ponds had a_ higher average weight than those from the © fertilized ponds, table 11. The number of captures of marked bass, those with which the ponds had been stocked in 1946, are indicated in tables 9 and 10. Few marked bass were caught after the second season of fishing. The — marked bass grew faster in some ponds — Table 13.—Numbers of bluegills, in various length classes, caught by Illinois Natural His- tory Survey test anglers in three unfertilized ponds at Dixon Springs. Bluegills of less than 6 inches in length were returned to the water. WELLS Boaz ELam Lencrs Crass, Incnes* (4 1948|1949/1950/1951)1952/1948) 1949|1950|1951/1952)1948 1949/1950)1951|1952 SCHR oo) ag pe eae Ae eee fo] Sy 2 1 Ve EA Pe 1H see foe 1)... 2] ees ee oF Le fo ae a a ie ras sat 5 1 9) 1 1 i] eared Weasel eee Baa 1 2 1 3 Me Vincedeecty Os ke Miia eae a OPS —4) 5 1 3 1 1 Eales 1)" 23 | se Glee: 4 EC Sea Sa Silo bl. 8i-2 Saat D ae 6| 4 1 3) (22-7) Ole 5 Ue ee... oh Saeed B71 211 | RG) 6|— Se eee 1 9} 9 14 16) 2 LS) 2) aaa ee Lien 23i- VT LA S89 8} 11 3] (12)... 8) S22ierss 1 (SIPS, oc A 5 BalSi) 13) 245 2|- 25) 9). 24) (2) 7) Sage ae 8 Sates tay ty Rh a rc 16ers |\-2 dl 7; 6; 10) 8 28} 6) 13) 9} 14! 51) 49 © FXO ip a Sa oh eho cana The TOP AB ATES 6} 4 3) 36) 5) 12) 15) 12)" 16) ome 7 Ae hee aren ee P a ieee nei jaa 53) meee: 4 Rioae of fuer! 143 ier 0A Uae, 1 Berens 1 3 1 2 1a BOS eS ROME en a Sects fie ae elton et leet tea 5 Sia it ice ace 1 1) eee 1 1) ee LG eget PR Eee SC epee! Web bawed Pier at Lore 13 | Ia | (el Ime mea Pr eT Porgl cues. 39) 86| 119} 103) 71| 52) 59| 53) 115) 19| 58) 95| 103) 168) 117 Number in 6-inch class or lage: cess 28} 37| 48) 64) 55) 16) 42) 21} 93) 14) 33) 31] 52] 101) 103 Average length of fish, 6-inch class or larger...| 6.5] 6.9| 6.6} 6.9) 7.0] 6.8] 6.3) 6.4! 6.6) 6.7| 6.6] 6.8) 6.4] 6.5) 6.7 Per cent in 6-inch class OPanttere et pc nl y8u9] etic oe en LTE ae Te eee Tk eee eS pines 0) ses JOBIv] Rte) 8 +0°0 10°0 (4 c0°0 € 60°0 LI 1z°0 +10 x4 Il’ 91 6£°0 a6 09°0 L9°0 OI L¥0 99 99°0 6cl $0°T 9L°0 Icl c9°0 £6 ya | ae (tae ea JoBIv] JO / 6h $61 OcE cel 981 6I'1 C&T CL'T bet 607 10°T cs $8°T i pita ee ae Jodie] 10 9 9 4 €L°T 8bh £8°I £97 8° 1 8hL L6'T 1S OFT 0c T [81 6I°¢ 79 |" tare] AO ¢ Let Ste ces 60°C $6T 80°T 90F 90°T Ld T 99T tT 881 8t'°€ te aa aa Jo8Iv] 10 % tS°T 0e°¢ Its Il°@ 867 PIe 8IF LOC =| «691 897 be" 1 88I 6C°£ (cf ae cea eS Joie] 10 ¢ Inop anoH{ sty Jaquiny tee Joaquin eae Joquinn ide ie Jaquny} aq [zaquiny axe Jaquiny Loquiy Jaquiny Jaqunn Jaquiny sequin Joquinyy rade ena Jaquiny | emacig ‘Q8vIOAY QSRIIAY - : ‘AYOOTLVD HLONG : (sinoH $91) (SsnoFy TFT) (SINOH $61) : (SINOH] 6$1) (sinoH] TST) (SINOH] S61 9 T Pug? wey zeog STM Redeem sdpoyg JayooH] ieee jdey souo AjUO 9y} 919M JoZiB] JO YIFUI] [B30 SGNOg GaZITILYAAN/) SAGNOqd GaZITILusay ‘uswJaysy 3893 a4} Aq } Sayoul (9 SUINsvow s][ISen[q “ET PUB ZT $214e} UI eB paseq ase SoINsy YoryM UO BIEP YOR “ZS6I—-8F6l poised 943 ur ssa[zuB 3893 AdAing AJOAsSIF] [BANVAY stourT]] Aq surysy yo snoy Jad painjdeo sars0gaz80 Yy3ZUa] SNOIIBA UT S][ISen{q Jo SIEquUINKJ—s] 2/421 Inoyy ag soquinn ‘QBcIDAY puog-9214 ] “4931, Pue YIZUI, JeIOY sayDUT gg jo sseq sapNpIUl Jess] 1O Q,, A1odaqe> Yyisuay, aya ajdurexe Joy QJ JO 6 214] WoIF ssejd YIsuUe] B UO paseq SI AjosIje) YIsueT yor], I rau) £ 80°0 $I 8o°0 cL 6L°0 OST SIT Lit It'll 607 ano ae Joquinn Jaquny (SINOH 681) wey 10°0 Cc 80°0 cl 970 th 09°0 96 IL°0 FIT IL°0 Fl Ino an Joaquin Jaquny (sinoH 09T) zeog SGNOg G&ZITILAAIN() £0°0 9 81°0 6¢ 6£°0 98 $9°0 OFT 9L°0 89 LL°0 OLT ano ae Joquny Jaquny (SInoH] 077) STIPM Joaquin yy ‘QSvIDAY puog - 2014, 70'0 | ZL vo-0- | Or 85°0 | #01 69°0 tl TAS ae har ANOH, Jog [2°T4IN Joquinn (SINOFY 6Z1) sdyeud aS ae cry a | ATES ame ther a | eas HUET, COL [ “2 9" *4 1ODIUT 10. Z ei whies ww iwi ealaesicate whew le, See eke 6 Mies I "+44" *IOBIBT JO QT aa Gt ci idl airmen tl epee ce £0'0 9 s+ 59 = IA OUI][-puB-yYOOF{— YZ 21qu] ayy wd ONIHSIY 40 sunoH “NVI ONIHSIY -NVIA| TVALOY Fetes aSpuaagr G3ZITILUAAN() LLL) “++ ++ -grepsapne’y GAZITILAG 6r6l ey eee, 2 STM GaZITLLYSAN() “+ a8psa0p- = 2 scyeuetse SNCs Uey “oss g7epsapne’y] GaZITILug 8rol RSE ‘asvsInp Fereeeee sess egTig gg eae ele Sasa Ua G4ZVILLY of Lol GNOg NV ¥VAX 369 HANSEN et al.: HooK-AND-LINE CaTCH August, 1960 0 97° 0 06 a) OL tc 0 09 ipo loco 870 8Fl EN) OST L9°0 981 Py nn Cee OF 0 9¢ 80°0 6 se°0 9] goo) tc (60) Is (0) 9 60° 8S Py LPO €? 6c 0 LI CeO 91 Fy, ee ce" 0 S¢ osm 6L $8°0 bP Wo | O10 cl ENO) 2) $70 Cl er'0 RP aa Aer : I¢°0 $e 970 oy 89°0 9¢ NaN aes os, ie wooon MNO MN AAs MADL le 0 61°0 L1°0 870 AY) L0°0 80°0 te (0) If0 AO) Oe" 0 8h 0 8l°0 90°0 90°0 cro £6°0 970 910 970 £10 O10 O10 61°0 0G" Ic 0 61 °0 0c 0 ol 0 L0°0 L0°0 cr O dja leh else eile tute 62°0 TiaGayahe tava, eca ar éte [pe mipelepete Pelle, shal ene Ilelfeiwitat wate kare Tene e NON VET 8: bl L7'0 901 797 0) Reman ia ge Gen “wey 8Z €7'0 101 11S 1 hid elite epee Tr ZB0G 08 (AS 0) POI Les CES Gr | eee weer “STP AY ZTIILYAANS) aWetan dé te eue be 4 02° U SN SCS SOME 1 PEG aes pe ine ee oR Ey LER LOI CeO ET 1 ge Z1°0 $9 Tes ess eS ee Saved 88 cl°0 It] 878 CO Ws eee JayOOH LOT $50 C91 TIE eee rot oesssorepispne Ty GAZITILAS Savas ]]V yap etre RIS Mens), 6 oe? SEE SG Re Paes a IS RO ee ge 1 12°0 61 gc Re eM Vortec wrly ce 9¢°0 OF 601 OI ree ee ee EA 3| Ge 750 $7 Lt ge MIM aga hese SIIPM GaZITILYAAN/) tow wee kenere” «(eee 16°0 Gina Pace ce aie | (as aad Samoa el sas Ora ha De ED I ua OP SEED ET ae 6 80°0 ra ISI 7A RMD pe ei sdeud Ol ZI°0 61 O71 OSI) Lr ee 19400 Ct 79°0 cc 8S cs Soest ayepropne’y GaZVIILya yf 7561 es dma le hes-ianeue Pin ceo Pee RS haste? aa ee emetic ean 4 mE NS AD OEE Eur ee el ESO 81 AS 6b Maes Wee | é 57°0 FI is 9S Hosier ezpog Cl 6£°0 61 os 6F ie Pia wanna) CY QaZITILYAAN/) gta. ey ohh ale’t hy cP ations na SLO pei aie pany fe cea ria eal Ee gare each ed ORCS AEY MONOD A Aili Ol e1°0 ia 101 1 Mean gana sdjoyd SI L1'0 tT 801 Chl ee sa ee J9yooH Or €t'0 ZI 95 TS Soe soypepiapne’y] GAZITILAs 1S6l siuetdeurantbyin (elrewler (e) eile If'0 SINE Ae aaa ai ea | a ees Ree MN A as OO VEEN: St cco 6¢ 9L SU Bait, tees ee wey y l 39m) ral 9¢ 9¢ 780g OL 87°0 al TS (SF ara gl? ss. see STIPM GAZITILUSANS) Whe) 0) 3 oO tar efresielieive vi 0£°0 Bee Ne ah tae eae aS a ag ee SE DR SOU RCS ET 8 FIO SI Sol 601 areas SPR U ay SI (allel) SZ 791 PCN eG Albee ce ee 19 00H Ct yO $f 85 CS "orcs oyepsopne’y GaZITILad OS6L 370 I_ttinois NAaturAL History Survey BULLETIN and Phelps, would have ranked better as bluegill fishing ponds than the controls even if no fertilizer had been used. H. W. Norton, statistician in the University of LARGEMOUTH 0.8 Orr HOOKER (F) PHELPS (F) WELLS BOAZ NUMBER PER HOUR ELAM 1947 1948 LAUDERDALE (F) —— 1949 Vol.:27, Aria Illinois Animal Science Department, tells us that where relative productivity of ponds is unknown the random selection of the three most productive ponds as the BASS 1950 1951 1952 Fig. 8—Number of largemouth bass kept per man-hour of angling in fertilized (F) and unfertilized ponds; data from table 20 August, 1960 HANSEN et al.: HooK-AND-LINE CATCH 0.7 LARGEMOUTH BASS LAUDERDALE (F)—— 0.6 HOOKER (F) —~A—— PHELPS (6): == 0.5 WELLS ee BOAZ : pe ELAM =! ° as xc WW a wn” a zs =) ° a 1947 1948 1949 w ~ aS 1950 1951 1952 Fig. 9—Weight of largemouth bass kept per man-hour of angling in fertilized (F) and unfertilized ponds; data from table 20. ones to receive treatment could occur once in 20 times. Although the ponds were chosen for fertilization on an arbitrary rather than on a purely random basis, we had no advance knowledge of how the six ponds might rank as fish-producing waters. The wide variation in catch rates for the three fertilized ponds at Dixon Springs points to the need for studies of catch rates on ponds before, as well as after, fertilization. A study of this kind is now in progress. Wells, Boaz, and Elam, the three control ponds of the study reported here, were restocked in 1954 and fertilized for two seasons. Bluegill catch rates in each of these ponds were better after fer- tilization than before. The fact that bass fishing in both Hooker and Phelps for the period 1947- 1952 was inferior to bass fishing in each of the control ponds, table 20, suggests several possible conclusions: (1) fertili- zation was of no help to bass fishing, (2) the benefits of fertilization varied greatly from pond to pond, or (3) no positive correlation existed between the fish population of a pond and the catch rate. The rotenone census of the fish populations showed that poor bass fishing in Hooker and Phelps may not have been due to scarcity of usable-sized fish in these ponds so much as to the difficulty of catch- ing them. That fishing for both bass and bluegills was generally much better in Lauderdale than in the other fertilized ponds is not easily explained, unless possibly by the lighter fishing pressure, as discussed in the section “Fishing Pressures and Catch Rates.”’ At the time of the 1953 rotenone census, the number per acre of usable- sized bass was smaller in Lauderdale than in Phelps; the number per acre of usable- 372 Ittinoris NaturAL History Survey BULLETIN Vol. 27, Art. 5 —A— 4.0 BLUEGILL LAUDERDALE (F)-—— HOOKER (F) 3.0 PHELPS (F) —-— WELLS —ee BOAZ = ELAM °o me xc WwW a c WwW @ = =) z 1947 1948 1949 1950 1951 1952 Fig. 10.—Number of bluegills kept per man-hour of angling in fertilized (F) and unfer- tilized ponds; data from table 20. sized bluegills was smaller in Lauderdale than in Phelps or Hooker, table 24. Three factors may have been favorable to the growth of fish in Lauderdale for 1 or 2 years at the beginning of the study but not during the last 4 years. (1) Be- fore the stocking of the ponds for the ex- periment reported here, fish-food organ- isms—invertebrates as well as larval am- phibians—had a longer time to build up their populations in Lauderdale than in Hooker or Phelps. In 1946 Lauderdale was without fish for 6 months prior to stocking (May to November), Hooker and Phelps for only 2 months (September to November). Brown & Ball (1943: 267) showed that certain fish-food organ- isms as well as fish were destroyed by the rotenone treatment of Third Sister Lake, Michigan. Ball & Hayne (1952: 44-5) showed evidence of an expansion in fish-food organisms in a lake after all fish had been removed. (2) In November, 1946, Lauderdale was given a slightly heavier stocking in terms of fish per acre than the other ponds; this heavier stock- ing might account for the better bass fishing in 1947. Presumably the initial advantage in numbers would have ceased to be a factor in 1948 or 1949, when the offspring of the fish used in stocking the pond reached harvestable size. (3) Lauder- dale had been dosed with fertilizer in 1945. As a result of an error in the reported area of the pond, Lauderdale received more fertilizer in terms of pounds per acre at full stage than either Hooker or Phelps. However, water levels in mid- summer were always much lower in Phelps than in Lauderdale, so that Phelps Le ee re To. A eo —— . ee alii tlie ae a — ie Pag ee Se ee ne ae ee ee eee ee ee ee eee ee ee ee August, 1960 was probably dosed at least as heavily as Lauderdale after about the middle of July each year. We have shown in table 8 that Lauder- dale was often clearer than Hooker and Phelps, a condition that might have as- sisted fish both in finding food and in locating baits. On the other hand, it is ro BLUEGILL 0.9 HOOKER (F) —A— PHERPS (ey —— 0.8 WELLS “ BOAZ —- 0.7 ELAM —x— PER HOUR POUNDS 1947 1948 1949 HANSEN et al.: HooK-ANp-LINE CaTCH LAUDERDALE (F) —— 373 possible that the clearer water increased the chances that the fish might be fright- ened by fishermen. Trends in Catch Rates.—Certain trends in the yearly catch rates were ob- served for both fertilized and unfertilized ponds at Dixon Springs, but trends dif- fered from one pond to another. In some 1950 195 1952 Fig. 11—Weight of bluegills kept per man-hour of angling in fertilized (F) and unfer- tilized ponds; data from table 20. Ww ¢ < 5 80°0 6 ze"0 < > st 0£°0 ce 9¢°0 OF 910 9 09°0 96 90°0 Or amy 61 OF'0 9€ L6'T LLI 91°0 al 1t°0 61 60°T 8s L8°¢ SOT tP°0 4 t9°0 ce im 67°0 LI es'T 68 90 6 $c'0 as & ce"0 91 6e°1 89 Lv'0 I 6£°0 61 5 $8°0 bP $9°T 8£I 61°0 Or £t"0 cl = Po 20S eT ES Ge et es ee ee ee ee ee eee ee ————————— $70 tl crt 9S 07°0 Ol 870 ial a 89°0 9€ 79°C 6€1 c'0 £% #9°0 HE z ee tee re ae ee ee - 9T°0 Il +6°0 99 +10 Ol 910 II he Le"0 61 eer 69 80°0 ie S1°0 8 2) +10 OL +9°0 LY 910 cl 970 6I az ce"0 16 6c £6 810 el ce"0 6 = | RSET CONE A hs aD it nn cm Ua Aira ROMEO Pses NSD. dak URi ana MA eeMicrmeet Meld ON (Raa Mele z 80°0 9 9¢°0 97 js) 0) cl 81°0 el 5 6£°0 ST? oat 611 91°0 Or cc"0 ial me ere ee i ee ee a Pi titanic late ol iafo lel | ols al eos arn af osm isis m4) «es eiwigin e's eines 6-04 oie It'0 Il 95°0 i py te ches eene aa Peae te ceceees[aes ats # yea Pee eae se £0°0 I 90°0 = ° 4 has ais 3 Inoyy nop] NOH ino i 19g iday log qday Jaq iday dq iday yday spunog yday Joquinyy iday spunog yday Jaquinyy spunog Jaquinyy spunog Jaquinyy sTIIOdA Tg SSVG HLNOWSOUV'T avoy wag ONIHSIY 40 sunoy ONIHSIY do sunopH IVALOY ee (Dd) zeog see (4) BE» (ole) 3 | eh eMe ible, efvalei4s (dD) wey "*"(q) ayeprepney cs61 "7" (q) S]epzepney Ts61 she ere ie «6. ale (9) STIPM. "**"(q) ayeprepne’y OS6l peso sl 6) meee el veers a (a sdisug Pie wr fe eee Se (Dd) STIPM "**"(q) syepsopne’y 66! ee (9) STTIPM. "7°" (q) sepsepney 8F6l as 2 bees 6 «8 (D9) STIPM Be Ue 0.0 tus (A) sdrayg L¥61 aNOg ANV ¥VaX ‘OZ 21qB3 Wosy a2e BIBG] “padnoss Jo pasted ase saryIsuazUT SuIYsYy sv[IWIS FuIAvY spuod (7) [O4}U0D 40 paZzI[HsajuN pu (4) peziynsey ‘spuod ssursdg UOXIC] Pe}99[9S Woy s][en[q pue sseq YINoWessB] JO (Surysy jo snoYy-ueWw sod yYsIeM puB JaquinU) paIA yO 9381 puL P[SIA dul[-puB-yooFy— IZ 2]quT 374 August, 1960 ponds, bass catch rates changed only slightly during the experiment; in others, catch rates were high at the beginning, dropped off for 1 or 2 years, and then improved toward the end of the experi- ment. The notion of many fishermen in Pope and Johnson counties that bass fish- ing in small ponds is best the first year they are fished was borne out in the fish- ing results only at Lauderdale and Wells, figs. 8 and 9. The observed depression in bass catch rates seen in some of the ponds in the second or third year after being stocked probably was due to a reduction in the numbers of the original stock of bass as a result of angling and natural mortality, combined with a delay in population re- placement through reproduction. In all of the ponds except Phelps and Lauderdale, figs. 10 and 11, bluegill catch rates were highest during the fourth year of bluegill fishing (the fifth year after stocking). Phelps Pond furnished its best bluegill fishing in the second year and Lauderdale in the fifth year of bluegill fishing. “The most common trend in bluegill catch rates—one that was ex- hibited by four of the six ponds—was a general improvement in rates over the first 4 years of bluegill fishing, 1948-1951. Three of these four ponds showed con- spicuous declines in catch rates in the fifth year, 1952. Fishing Pressures and Catch Rates.—Bennett & Weiss (1959) re- cently showed that ponds in I]linois sub- jected to comparatively light fishing pres- sures—Ridge Lake, Big Pond, and the ponds in the present experiment—pro- vided better catch rates than ponds in the Busch Wildlife Area, Missouri, that were subjected to extremely heavy fishing pres- sures. Although we were unable to discover a clearcut relationship between _ fishing pressures and catch rates in the Dixon Springs ponds, we found that the two ponds with the smallest total number of man-hours of fishing, Lauderdale (fer- tilized) and Wells (unfertilized), had the highest catch rates of bass of desirable sizes, table 20. We have tried in the following discus- sion to eliminate fishing pressure as a possible factor in catch rate calculations HANSEN et al.: Hook-AND-LINE CATCH 373 by comparing only those ponds that were fished at approximately equal rates, table 2 Under equal or nearly equal fishing pressures, bass fishing was in some in- stances better in the fertilized ponds, in other instances better in the controls, but bluegill fishing was consistently better in the fertilized ponds. The catch rates shown for Lauderdale (fertilized) and Wells (control) are of special interest because fishing in these two ponds was done almost entirely by the Natural History Survey test anglers, assuring that not only the number of hours but fishing skills and fishing meth- ods were nearly the same in a given year. In the + years that Lauderdale and Wells are represented in table 21, bluegill fishing in terms of number of fish caught per hour was 1.9 to 5.2 times as good in Lauderdale as in Wells—in terms of pounds caught per hour, 2.3 to 4.9 times as good in Lauderdale as in Wells. In the same 4 years, bass fishing was notably bet- ter in Lauderdale than in Wells in 1 year, better in Wells than in Lauderdale in 1 year. Over the entire period of study, total hours of fishing were nearly equal for Lauderdale (fertilized) and Wells (un- fertilized), each fished about 300 hours, and for Phelps (fertilized) and Boaz (unfertilized), each fished in the neigh- borhood of 500 hours, table 20 (bottom). The catch rates for bass, in 6 years of fishing, were better in Lauderdale than in Wells but better in Boaz than in Phelps. The catch rates for bluegills, in 5 years of fishing, were considerably better in Lauderdale than in Wells and somewhat better in Phelps than in Boaz. Fertilization Rates and Catch Rates.—As described in the section “Fer- tilizing the Ponds,” the N-P-K formulas used in the period 1947-1949 were dif- ferent from the ones used in later years, table 7. As a consequence of changes in the fertilizer formula and in the number of treatments, the ponds received about 2.0 times as much nitrogen, 1.3 times as much phosphorus (P,O,), and about 3.2 times as much potassium (K,O) in 1951 and in later years as they had received each year in the period 1947-1949. Al- though the number of fertilizer applica- 376 Ittrnois NATURAL Hisrory Survey BULLETIN Vol. 27 ArteS Table 22.—Catch rates (number and weight of fish per man-hour of fishing) of largemouth bass and bluegills from Dixon Springs ponds in two periods, one of comparatively light (1947- 1949) and one of comparatively heavy (1951, 1952) fertilization. Details of pond fertilizaticn program are shown in table 7. Figures were derived from data in table 20. LARGEMOUTH Bass BLvuEGILLs* : FERTILIZATION - am LES [ES PEROR ON ES aENe Number Pounds Number Pounds Per Hour Per Hour Per Hour Per Hour Licut (1947-1949) Fettiiized ponds isi 85 asa ss fe 0.27 0.16 1.05 0.26 Unfertilized ponds..............| 0.23 OrTy 0.65 0.13 Diff erencéc chtetoe -ctacter Bates | +0.04 —0.01 +0.40 +0.13 Heavy (1951, 1952) | Fertilized ponds ee ee tia 0.23 0.16 1.88 0.55 Unfertilized ponds.............. 0.35 0.27 1.46 0.32 DOS EVENCE = ise WAeh ea oe eae —0.12 —0.11 +0.42 +0.23 *Bluegill fishing in 1948, 1949, 1951, and 1952 but not in 1947. tions given annually in 1951-1953 was double the number given in 1947-1949, the amount of phosphorus (the compo- nent generally considered to be most im- portant in pond fertilization) was in- creased only about one-third. Catch rates may be compared for the years under the lighter treatment (1947-— 1949 for bass, 1948 and 1949 for bluegills) with the years under the heavier rates (1951 and 1952), table 22. Bass fishing, as judged by differences in catch rates be- tween fertilized and unfertilized ponds, was relatively better under the lighter treatment; bluegill fishing—especially in pounds caught per hour—was better un- der the heavier treatment. Since bluegill catch rates improved in the control ponds as well as in the fertilized ponds during the period of the heavier treatments, blue- gill fishing might have improved in the fertilized ponds even if the rate of fertili- zation had not been increased. POND FERTILIZATION AND STANDING CROPS When the standing crops of the Dixon Springs ponds were determined by ro- tenone censuses in September, 1953, the ponds had been closed to all fishing for the 12-month period preceding the census. Fertilization of Lauderdale, Hooker, and Phelps had been continued during the summer of 1953 in approximately the same manner as in 1951 and 1952, table 7. For each pond the standing crop in pounds per acre was computed from the reduced area of the pond at the time of the census, rather than from the area at full stage. Both full stage and reduced areas are shown in table 1. Studies by Brown & Ball (1943), Ball (1948), Carlander & Lewis (1948), and Krumholz (1950a) demonstrated that in some situations considerable percentages of the populations of fish killed by rote- none are not recovered in the census op- erations. A possible hindrance to the re- covery of fish in the control ponds at Dixon Springs was a dense growth of Chara in which dying and dead fish might — have become entangled. The possibility that the Chara interfered with the re- covery of fish was not investigated by un- derwater examination. We know of no reason other than the possible effect of Chara to believe that the percentage of fish recovered was different in fertilized — than in unfertilized ponds. Bass collected from the ponds after the rotenone treatment were grouped into two length categories—those 10.0 inches (total length) or larger and those smaller than 10.0 inches. The bluegills collected from the first four ponds examined (Lauder- dale, Phelps, Wells, and Boaz) were divided into four length categories as fol- — lows: inches or larger. various length categories, for the most 1.0-1.9, 2.0-3.4, 3.5-5.9, and 6.0m Natural size groupings — permitted the rapid sorting of fish into the ~ Asciaeg August, 1960 HANSEN et al.: part without actual measurement. Blue- gills collected from the other two ponds (Hooker and Elam) were grouped into two categories: under 6.0 inches and 6.0 inches or larger. The populations of the first four ponds varied considerably with respect to abund- ance of bluegills in the four length cate- gories, table 23. The variations appear to have been unrelated to the fertilization program. Lauderdale Pond was char- acterized by an absence of bluegills 1.0- 1.9 inches long, by an spinidance of bine: gills 2.0-3.4 inches long, and a relative scarcity of bluegills 3.5—-5.9 inches long and 6.0 inches or larger. ‘This pond, in which bluegill fishing had been better than in any other, was more remarkable for the weight of 2.0—3.4-inch bluegills (95 pounds per acre) than for the weight of bluegills measuring 6.0 or larger. Two population characteristics were seen in these four ponds, table 23. (1) While the ponds appeared to be quite densely populated with bluegills under 3.5 inches, they showed no evidence of overpopulation with bluegills of 3.5 inches or longer. (2) In number of bluegills per acre in each of the four ponds, great dif- ferences existed between the two smaller length categories and only minor differ- ences between the two greater length cate- gories. Of the fish that, according to tables 12 and 13, were likely to be caught by anglers (those 3.5 inches or larger), the ones measuring 3.5—5.9 inches were about as numerous as those of greater lengths. HooKk-ANb-LINE CATCH 377 The number and weight of bass and bluegills (in two length categories for each species ) recovered from Ue of the six ponds in the rotenone census are shown in table 24. Just as there was overlap in the catch rates for fertilized and unferti- lized ponds, there was also overlap in the standing crops. Bass 10 inches or larger, bluegills 6 inches or larger, and bluegills smaller than 6 inches were a little more abundant in the fertilized ponds, while bass smaller than 10 inches were more abundant in the control ponds, table 24. Rass of all lengths were more abundant in the control ponds, while bluegills of all lengths were more abundant in the fertilized ponds. The weight per acre of bass of all lengths was nearly the same in fertilized as in control ponds; the weight per acre of bluegills of all lengths was higher in the fertilized ponds. The three fertilized ponds averaged 292 pounds of fish per acre (bass and bluegills of all lengths) ; the controls averaged 238 pounds per acre (ratio 1.2:1). In Alabama ponds treated nine times a season with 6-8-4 fertilizer at the rate of 100 pounds per acre per treatment and NaNO, at the rate of 10 pounds per acre per treatment—roughly equivalent to the annual treatments applied at Dixon Springs in the period 1951-1953—Swingle (1947:24) found that the average stand- ing crop (weight per acre) of bass and bluegills of all sizes in three fertilized ponds was about double the standing crop in the control pond (ratio 2.0:1). In this Alabama observation, an overlap was Table 23.—Standing crops, in terms of number and weight (per acre), of bluegills recov- ered in the rotenone censuses of four of the six Dixon Springs ponds, September 8-17, 1953; the fish were separated into four length categories. The data from Hooker and Elam ponds are not included in this table because the bluegills from those ponds were separated into only two length groups, under 6 inches and 6 inches and longer. FERTILIZED Ponps UNFERTILIZED PonpDs Tora LENGTH, Lauderdale Phelps Wells Boaz INCHES Number | Pounds | Number | Pounds | Number | Pounds | Number |} Pounds Per Acre | Per Acre | Per Acre | Per Acre | Per Acre | Per Acre | Per Acre | Per Acre De il - a ea artes ee aCe (tae ee 9,070 10 12,428 | 27 921 | 1 a ne 11,531 95 227 Se esO8e Ulan oe 7905, ))) aot OSS eee 314 Dh| 676 50a 451 | 27 876 | 56 6.0 or larger... 463 129 706 146 463 108 624 133 00°T 00°T 00° 00°T 00°T 00°T pezyseyaQ £0°T bL°0 PFO £9°0 OFT (om | Pee psed OZ 926 LE OFe isa OF a Sa kv at optptray mes a3vAanpy 3 LOT c est It Petal) sah erie oneal | L6 cle st €ST (6) Go oa gk eee nt 69 OI FC SST SP S$ STTPAA CAZITILUFAN() BZ £06 él OFT 09 Oe SS eee a £6 9ST 9% C6 Ly +9 eS ara Is 8L7 8 607 cP GF SBA ete aeaOCH €Z Sdl c Lit OL 8S - Reread sail seca CaZITILAA ay ay ay ay ay ae wy dq Jog 1g dq 12g 13g spunog | Joquingy | spunog | Joquiny | spunog | aquiny aNog [PIO], yeus ase] vw ¢ < py N s > 0071 00°T 60°T 00'T 00°1 00'T 00°T 00°T Zz ag ert og" SII og’ Cid tel yo te = BES ae ane “4 8£E 969'8 89] 0éb'8 19 O16‘ L ZO1 Ors 3) 691 OLe'S 971 e9T's St IL’ 18 (oa ra soe 859°9 LIZ 9FE'9 8L ZL 'S Cel $79 z LEZ 090‘F1 891 OSL‘EI 09 EST ST 801 COF > 268 898°6 61é £99'6 6 £906 Itl 665 = ZOE s€8 ‘Ol 607 6L9°01 ¢9 £166 oF 90L > SSZ $879 $07 L00°9 Lg BLES L¥l 679 S gic Ct ‘ZI SFT soe “ZI cal Se ‘II yal CoF E = —_ — a — — - IDYy ay oY ay IY | IY Pe) 4 wy 5 419d 412d 419d 19 1d Rd Iq 19q a spunog JOq Un Ay spunog JOq un Ny spunog JOq Win spunod Joquinyy < Pa ee = E 3 5 =) z GaNIg#Wo-) SAZI§ v ol ems oe Z, ANV SdIOads : 5 STIIOSF OTE ~ 378 SSVq HLNOWSOUV'T “19SU0] JO YISUa] [B}0} SayoUT (9 DSOY} BIIAA S][ISaN[q os1B] Ssasuo] JO YISUa] [B}0} SaYyoUT (MT SOY} oJaM Sseq asieyT “spuod PeZiwsajun pue pezi[nsey usamjoq (e108 Jod }Y4sIaM puB JoquINU UT) OBI 94} ‘saIdads YyoBO IO} ‘puB ‘CCE, ‘/[—Q Jaquiajdag ‘auoUsI01 Y}IM paj}Be73 spuod sfursdg uoxig] 94} WoOsy pas9A0dal s]|[ISaN[q JO pue sseq YINnOWPZIB] yo ‘(9108 Jad) }YS1I9M puB Jaquinu JO suwsa} UI ‘sdosd SuIpuL}g—}z 2/qB] August, 1960 found between fertilized and control ponds in standing crops of bass but not of blue- gills. In another experiment in which Ala- bama ponds were treated 12 times a sea- son with 6.6-8-2, each time at the rate of 120 pounds per acre, Swingle (1947: 22) found that the average of the standing crops of bass and bluegills of all sizes in three fertilized ponds was nearly three times the standing crop in the control pond (ratio 2.9:1). That Alabama ponds showed a better response to fertilization than the Dixon Springs ponds under similar treatment is possibly explained by differences in natural fertility of the Alabama and Illi- nois ponds in question. It might be easier through direct fertilization to double or triple a low standing crop of fish in an area of low soil fertility than in one of somewhat higher soil fertility. The un- treated Alabama ponds, 6 to 12 months after being stocked, contained 100 to 125 pounds of bass and bluegills per acre (Swingle 1947: 22, 24), whereas the three untreated ponds at Dixon Springs, 6 years after being stocked, contained 169 to 308 pounds of bass and bluegills per acre, table 24. It is possible that in the 6- to 12- month periods between the stocking and draining of the Alabama ponds the stand- ing crops had not had time to reach maxi- mum levels. Krumholz (1948: 405, 409) found that ponds stocked in May or June with bluegills alone or with bluegills, largemouth bass, and other species con- tained much larger standing crops the second October than the first October after being stocked. Ball & Tait (1952:6, 17) used some- what less fertilizer in southern Michigan ponds than was used at Dixon Springs in 1951-1953 and obtained a slightly better response from the treatments. ‘Three Michigan ponds were treated five times a season with 10-6-4 fertilizer at the rate of 100 pounds per acre each time. The fertilized ponds had standing crops of bass and bluegills that averaged 365 pounds per acre, and three similar, un- fertilized ponds had standing crops that averaged 261 pounds per acre (ratio 1.4:1). There was a very wide range in the standing crops of the fertilized ponds, 165 to 721 pounds per acre; the HANSEN et al.: HooK-ANp-LINE CatcH 379 standing crops of the unfertilized ponds ranged from 209 to 379 pounds per acre. In West Virginia, Surber (1948d) studied the effect of various rates of ap- plication of 10-5-5 fertilizer on the blue- gill production in hatchery ponds. Three groups of ponds were treated five to seven times a growing season at rates of 100, 200, or 300 pounds of 10-5-5 fertilizer per treatment. Combining the data of Surber (19484:201-2) for summer and _ fall hatchery crops (but omitting the data from a pond in which there was abnor- mally high mortality) we find that crop weights were 1.9, 2.3, and 2.3 times as large in the three groups of fertilized ponds as in the control ponds. STANDING CROPS AND FISHING SUCCESS For many years aquatic biologists have been interested in the standing crops of lakes and ponds as a basis for predicting hook-and-line yields. Thompson (1941: 213) thought that central Illinois lakes stocked with bass, bluegills, and crappies could give sustained annual hook-and-line yields that would amount to half their carrying capacities. He thought that the corresponding yields for southern Illinois lakes might be close to three-fourths of their carrying capacities. By carrying capacity, “Thompson meant the _ total amount of fish in a lake at saturation point, or the maximum standing crop. Krumholz (19504: 29) estimated that In- diana ponds were capable of giving sus- tained annual yields of “as much as half and perhaps more”’ of their standing crops. Neither Thompson nor Krumbholz spec- ulated on the amount of fishing time that might be required to bring about such yields. We may now compare the hook-and- line yields of the Dixon Springs ponds during the last 3 years of fishing with the standing crops as observed in the 1953 censuses, table 25. ‘The hook-and-line vields were for the most part made up of bass more than 10 inches and _ bluegills more than 6 inches total length; the stand- ing crops included all fish, irrespective of size. For each Dixon Springs pond, the 1952 yield alone, as well as the average yield 380 for the years 1950, 1951, and 1952, amounted to a much smaller percentage of the standing crop, as observed in Septem- ber, 1953, table 25, than the sustained yield estimates of Thompson and Krum- holz. Percentages were higher in the fer- tilized than in the control ponds. ‘The most heavily fished ponds in 1952 were Hooker, Phelps, and Boaz. The 1952 fish yields in these three ponds were respec- tively 11, 19, and 14 per cent of their observed standing crops. The largest yield in relation to standing crop (28 per cent) was recorded from Lauderdale Pond, where fishing in 1952 was lighter, rather than heavier, than in Hooker, Phelps, or Boaz. If, as is possible, fewer fish were recovered in the rotenone censuses than were actually present, the true percentage values would be even lower than those shown. On the other hand, if unreported yields of fish taken by poachers could be determined and included in the calcula- tions, the percentages for at least some of the ponds might be higher than those shown. Figures representing the 1952 bass har- vest and the numbers and weights of harvestable bass in the ponds at the time of the 1953 census are shown in table 26. Similar figures for bluegills are shown in table 27. If the 1953 fish census gave a close approximation of the population of harvestable fish in 1952, the efficiency of Ittinors NAtuRAL History Survey BULLETIN Vol. 27, Art.’5 the 1952 fish harvest (the fish caught in relation to the fish present) appears to have been greater for bass in the control ponds and for bluegills in the fertilized ponds. The relations between catch per hour and the abundance of fish of desirable sizes are shown for bass in table 28 and for bluegills in table 29. Data in these tables, especially the ratios expressed, seem to indicate that in the fertilized ponds bass fishing was poorer than would be _ expected from the numbers of 10-inch or larger bass present and that bluegill fish- ing was better than would be expected from the populations of 6-inch or larger bluegills. Swingle (1945:305) observed that the catch in fertilized ponds was usually greater than would be expected from the increases in their fish-carrying capacities, but he did not say whether his observa- tion applied to both bass and bluegills. He attributed the phenomenon to the blooms of microscopic algae, which he be- lieved helped to conceal the anglers from the fish they were trying to catch. Results of the Dixon Springs experiment indicate that if plankton algae helped to conceal the fishermen from the bass it may also have helped to conceal baits from these fish. We have ordinarily assumed that the pond containing the largest population of Table 25.—Standing crop of largemouth bass and bluegills (fish of all sizes) in the 1953 rotenone census of the six Dixon Springs ponds, and the hook-and-line yield of largemouth bass and bluegills during the last years of the experiment, 1950-1952. Yield data are from table 15, standing crop data from table 24. ANNUAL HooK-AND-LINE YIELD AS A PERCENTAGE OF STANDING Y1eELD, PounpDs PER ACRE STANDING Crop Ponxp Crop, Pounps ee 1950-1952 ae 1950-1952 1952 Average Average FERTILIZED Lauderdale...... 318 88 70 28 22 IOOK eRe c eicke sesie 255 27 50 11 20 Phelpsi eu: toys 302 58 48 19 16 RUPEE O Sve slates [ois fod aes aa shat hsce mca ORE eee ere 20* 19* UNFERTILIZED Wells Ay. fia helen 238i, 39 30 16 13 | bay ease ear en pibee oe 308 42 27 14 9 Blame wdc 169 32 26 19 1 RAPEI IED Cla ate a tikes. iipbe 83° aura) tsi] Ge SecA O peaee Seoece el ee 16* Lee *Average of three percentages directly above. August, 1960 HANSEN et al.: HooK-AND-LINE CATCH 381 fish of desirable sizes is the one likely to prisingly little correlation was found be- provide the best fishing. However, sur- tween numbers of bass and bluegills of Table 26.—The 1952 hook-and-line yield of largemouth bass (number and pounds per acre) as a percentage of the 1953 rotenone census figure in each of the Dixon Springs ponds; also the ratio of fertilized to unfertilized ponds in number and pounds of bass per acre. Basic data are from tables 15 and 24. LarGEMOUTH Bass 1952 YIELD As A PERCENT- 10-INCHES OR LaRGER, eerie: ae YIELD, AGE OF 1953 CENsuUS 1953 RoreENOoNE CENSUS SAG SEASON Ficure Ponp ; Number Pounds Number Pounds Number Pounds Per Acre Per Acre Per Acre Per Acre Per Acre Per Acre FERTILIZED Lauderdale.... 58 70 36 25 62 36 Hooker....... 49 43 14 7 29 16 helps... ...:. 64 67 12 9 19 13) Average....... i 60 21 14 37 f 22T UNFERTILIZED WVElIS. «5.16 ws: 55 45 25 23 45 51 | EXO 6 eee en ei 59 62 40 33 68 53 Blame. <6: - 24 21 12 9 50 43 Average....... 46 43 26 22 544 497 Fertilized 1.24 1.40 0.81 OSG4 cag Ween a eee |e ee Oe Unfertilized 1.00 1.00 1.00 Te OOP gl eee aac eter hs a S| ee ge ee *The hook-and-line yields of bass from Lauderdale and Wells were made up of fish measuring at least 10.0 inches total length. No measurements of bass caught by permit fishermen were recorded, but these fishermen were supposed not to keep bass less than 10.0 inches in length. +Average of three percentages directly above. Table 27—The 1952 hook-and-line yield of bluezills (number and pounds per acre) as a percentage of the 1953 rotenone census figure for each of the Dixon Springs ponds; also the ratio of fertilized to unfertilized ponds in number and pounds of bluegills per acre. Basic data are from tables 15 and 24. BLuecILits 6 INCHES oR BLueGILLt YIELD, 1952 Yre_p as A PERCENT- Larcer, 1953 1952 FisHInG AGE OF 1953 CENSUS RoTeENONE CENSUS Season* FIGURE Ponp ; ie Number Pounds Number Pounds Number Pounds Per Acre Per Acre Per Acre Per Acre Per Acre Per Acre FERTILIZED Lauderdale... . 463 129 223 63 48 49 Hooker. ...... 629 147 72. 20 11 14 Phelps........ 706 146 160 49 23 34 AGS Ne 599 141 151 44 277 Bei UNFERTILIZED \El ee 463 108 59 16 13 15 Deh. 624 1333) 35 9 6 7 knee 442 81 114 23 26 28 WAUETAGE...:..« 510 107 69 16 15+ 177 Fertilized 1S USK 131 2.19 DreT Sih. KORE ee PER Cie all Meat ae WE eae Unfertilized 1.00 1.00 1.00 LOO.) eee er eee eee *The hook-and-line yields of bluegills from Lauderdale and Wells were made up of bluegills measuring at leact 6.0 inches total length. The sizes of fish taken from the other ponds were not governed by restrictions on fishermen. jAverage of three percentages directly above. 382 Intinors Natura History Survey BULLETIN Vol. 27, Art. 5 desirable sizes in the several ponds in the cess in the same ponds in the preceding 1953 census and the record of fishing suc- years, tables 26-29. Lauderdale, the pond Table 28.—Number and pounds (per acre) of largemouth bass of at least 10.0 inches total length in the 1953 rotenone census, the hook-and-line catch rate for 1952, and the average annual hook-and-line catch rate for 1950-1952 in each of the Dixon Springs ponds; also the ratio of fertilized to unfertilized ponds in number and pounds of bass per acre and per hour. Basic data are from tables 20 and 24. LarRGEMOUTH Bass, CaTcH PER LARGEMOUTH Bass Man-Hour* \LOIncHes or Larcer, 1953 RoTrenone CENSUS Ponp . 1952 1950-1952 AVERAGE Number Pounds Number Pounds Number Pounds Per Acre Per Acre Per Hour Per Hour Per Hour Per Hour FERTILIZED Lauderdale.... 58 70 0.62 0.43 0.50 0.35 Hooker....... 49 43 0.12 0.06 0.14 0.08 Phelps. 64 67 0.08 0.06 One 0.08 Average 57 60 0.27 0.18 0.25 0.17 UNFERTILIZED Wrellste ses 55 45 0.52 0.48 0.39 0.32 BORZ eee 59 62 0.36 0.30 0.31 0.22 Blames. bee: 24 21 0.21 0.16 0.30 0.21 LLDET OEE snehe ss 46 43 0.36 0.31 0.33 0.25 Fertilized 1.24 1.40 0.75 0.58 0.76 0.68 Unfertilized 1.00 1.00 1.00 1.00 1.00 1.00 *Information on the sizes of bass in the catch is in the first footnote to table 26. Table 29——Number and pounds (per acre) of bluegills of at least 6.0 inches total length in the 1953 rotenone census, the hook-and-line catch rate for 1952, and the average annual hook-and-line catch rate for 1950-1952 in each of the Dixon Springs ponds; also the ratio of fertilized to unfertilized ponds in number and pounds of bluegills per acre and per hour. Basic data are from tables 20 and 24. BLuEGILts, CaTcH BLvueEcILts 6 INcHES Per Man-Hovur* or Larcer, 1953 RotTeNONE CENSUS Ponp 1952 1950-1952 AVERAGE Number Pounds Number Pounds Number Pounds Per Acre Per Acre Per Hour Per Hour Per Hour Per Hour FERTILIZED Lauderdale.... 463 129 3.87 1.09 3.05 0.88 Hooker....... 629 147 0.60 0.16 1.15 0.32 Phelps: > i565 % 706 146 1.06 0.32 1.03 0.32 Average....... 599 141 1.84 0.52 1.74 0.51 UNFERTILIZED Wellsiz os 3-: 463 108 1.24 0.35 1h 245) 0.31 Boazastenee 624 133 0.32 0.08 0.89 0.18 Blamcca sce 442 81 1.97 0.40 1.55 0.32 Average....... 510 107 1.18 0.28 1223 0.27 Fertilized 7; 15332 1.56 1.86 1.41 1.85 Unfertilized..... 1.00 1.00 1.00 1.00 1.00 1.00 *Information on sizes of bluegills in the catch is in the first footnote to table 27. August, 1960 that had generally furnished the highest yields and catch rates did not at the time of the census contain the largest popula- tion of fish of desirable sizes, while Phelps, which had consistently furnished poorer fishing than Lauderdale, contained a rela- tively large population of bass and _ blue- gills of desirable sizes, tables 28 and 29. Assuming that our data were adequate for the comparison just made, we may conclude that our failure to find a closer relationship between standing crops and fishing success was due to one or both of the following reasons: (1) the stand- ing crops were not the same in all years of the experiment; (2) catch rates were greatly affected by some factor other than the size of the standing crops. FIELD FERTILIZATION AND FISHING SUCCESS The application of chemical fertilizers to fields draining into ponds is sometimes thought to be a benefit to fish production and fishing in such bodies of water. This line of thinking is consistent with the widely accepted idea that fertility of the land comprising the watershed of a lake or river has a profound effect on fish production. Little has been said in the literature of pond fertilization, however, concerning the extent of the benefits to pond fishing that may be derived from watershed treatment. The quantity of fertilizer that might reach a pond in runoff from its watershed would vary from one pond to another and would be difficult to estimate. It would depend, for example, on the size of water- shed, the kind and amount of fertilizer used, and the extent to which it was mixed with the soil as it was applied. It would also depend on the time lapse between fertilizer applications and occurrence of rainstorms, the severity of the storms, the tendency of the soil to erode, and the den- sity of protective vegetation. Part of the fertilizer washed from fields into ponds would later be lost over the pond spill- Way. Phosphorus applied ‘to fields as rock phosphate is slowly soluble and, theoret- ically, would be of less benefit to a pond than phosphorus applied as_ superphos- phate, which is readily soluble. However, HANSEN et al.: HooK-ANpD-LINE CATCH 383 phosphorus applied to fields in the form of superphosphate combines rapidly, in the presence of moisture, with elements in the soil to form slowly soluble calcium phos- phate and relatively insoluble compounds with iron and aluminum. Except for the superphosphate that might be washed from a field into a pond very soon after a soil treatment, the phosphorus carried into a pond from its watershed would be in a relatively insoluble state. Nitrogen and potassium would be present in runoff for a comparatively short time, probably less than a year. Nitrogen is taken up quickly by plants or is lost into the air, while potassium salts tend to leach downward into the soil, where they cannot be re- moved by water running over the soil surface. In the period 1935-1937, previous to the beginning of the study reported here, fields surrounding each of the Dixon Springs ponds were given an application of crushed limestone, and fields surround- ing three of the six ponds (Lauderdale, Wells, and Elam) were treated with superphosphate, table 5. In the course of the study, the water- shed of each pond was again treated with crushed limestone; for the first time each watershed was treated with rock phos- phate and each watershed except that of Phelps was treated one or more times with chemical fertilizers supplying nitro- gen, phosphorus, and potassium, separately or all three in combination, table 5. Barn- yard manure was applied to one of the fields. Actual demonstrations of the effect, on fishing success, of crushed limestone ap- plied to ponds or pond watersheds in the United States seem to be lacking. In Europe, Schaeperclaus (1933:162) re- ported that applying lime to pond bottoms protects the health of fish and produces favorable “biological conditions, which react to increase the yield.’’ Because the watersheds of all Dixon Springs ponds received approximately equal applications of limestone, no conclusions can be drawn as to what effect, if any, liming of the watersheds had on fishing success in these ponds. Although phosphorus is generally be- lieved to be important as a pond fertilizer, its value to fishing when applied to pond 384 watersheds is difficult or impossible to de- termine from data gathered in the Dixon Springs experiment. The water of Boaz, the only control pond that had no record of superphos- phate, rock phosphate, or complete fer- tilizer application to its watershed until 1949, had a higher phosphate content in 1947 than the water of any of the other five ponds at Dixon Springs, table 3. It is interesting to compare catch rates I_ttino1is NATURAL History Survey BULLETIN Vol. 27, Ar am in Boaz with catch rates in the other con- — trol ponds before rock phosphate was ap- plied to part of the Boaz watershed in the — fall of 1949. Superphosphate had been ~ applied to the Elam watershed in 1936 and to the Wells watershed in 1937. In the years 1947-1949, bass fishing was not _ so good in Boaz as in Wells or Elam. In — 1948 and 1949, bluegill fishing was slight- — { ly better in Boaz than in Wells but not — quite so good as in Elam, table 30. . Table 30.—Catch rates (number and pounds of fish removed per hour of fishing) at Dixon . Springs ponds, 1947-1952. Years in which fertilizers were applied to pond watersheds are indi- cated by S (for spring preceding the fishing season) and F (for fall near the end of the fishing — season). Data are from table 20. Additional data on watershed fertilization are in table 5. LarRGEMOUTH Bass BLUEGILLS aie —— Number Pounds Number Pounds 3 Per Hour Per Hour Per Hour Per Hour © FERTILIZED anderdales . 2.0 eee wee 1947 1521 0.72° |e... SS 1948 0.22 0.16 1.86 0.39 1949 0.32 0.18 1.29 0.32 1950F 0.64 0.43 2.62 0.68 1951 0.23 0.19 2.65 0.85 1952SF 0.62 0.43 3.87 1.09 TIOGR ER ta oe ee be ee 1947 0.08 0.05 |....... 223 aS 1948 0.12 0.09 0.87 0.21 1949S*F* 0.14 0.09 0.59 0.17 1950 0.12 0.07 0.82 0.26 1951F* 0.17 0.10 2.02 0.55 1952 0.12 0.06 0.60 0.16 PH eMDSe) to rene a senha ee a 1947 0.06 0.03}... one. spare « alle 1948F 0.14 0.06 0.37 0.09 1949 0.15 0.08 1.33 0.36 1950 0.14 0.07 0.96 0.31 1951 0.13 0.10 1.08 0.33 1952 0.08 0.06 -1.06 0.32 UNFERTILIZED Wellsaiin or Fed eo hae: 1947 0.56 0.41 weeecesveaeelecir. naa 1948 0.18 0217 0.36 0.08 1949 0.26 0.16 0.64 0.14 1950F 0.28 0.20 trat2 0.24 1951 0.39 0.26 1.39 0.33 1952F 0.52 0.48 1.24 0.35 SOA Er eth ees he eee 1947 0.25 0.17 Se ee eS 1948 0.11 0.13 0.47 0.10 1949F* 0.09 0.05 0.78 0.16 1950 0.33 0.19 0.83 0.17 1951S*F* 0.24 0.16 1.53 0.29 1952 0.36 0.30 0.32 0.08 Big ee aces eee cee tes 1947 0.32 0.20 Ls 1948 0.20 0.13 0.68 0.15 1949 0.16 0.14 0.94 0.16 1950 0.33 0.21 0.34 0.10 1951 0.37 0.26 2235 0.47 1952SF 0.21 0.16 1.97 0.40 *Only part of watershed treated with fertilizer in this season. August, 1960 Bass catch rates improved in Wells Pond in 1951, following fertilizer treat- ment of its watershed in the fall of 1950, and in Boaz Pond in 1950 and 1952, fol- lowing treatment of half of its watershed in 1949 and the other half in 1951, table 30. A drop in the bass catch rate oc- curred in Elam Pond in 1952, after treat- ment of its watershed in the spring of that year. Bluegill catch rates rose slightly in Boaz in 1950, following treatment of half of its watershed in the fall of 1949, and in Wells Pond in 1951, following treat- ment of its watershed the previous fall. The bluegill catch rates improved in Boaz in 1951, following treatment of part of the watershed in the spring of that year, but they declined in 1952, after treatment of another part of the watershed in the autumn of 1951. They declined in Elam in 1952, following application of fertilizer to its watershed in the spring of that year. That the field treatments may not have been the cause of improved bluegill catch rates in Wells is indicated by the trend in catch rates leading up to the field treat- ment of 1950; bluegill catch rates were showing year-to-year improvement before this treatment. Examination of the catch rates for the directly fertilized ponds, Lauderdale, Hooker, and Phelps, in the fishing seasons following both direct and indirect fer- tilization shows that in some cases bluegill fishing was better in the season after a field treatment than before, table 30. However, in most of the cases the im- proved fishing could have been caused by the increased rates of pond fertilization, which were begun in the spring of 1950, rather than by the field fertilization. While the evidence that field fertiliza- tion may have helped fishing in the Dixon Springs ponds is inconclusive, we should perhaps state our conclusion on pond fer- tilization as follows: that, in addition to any improvement in fishing success that might have resulted from watershed treat- ments, there is evidence of improvement in bluegill fishing from direct fertilization -of the ponds. The pond owner who strives for better bluegill fishing should therefore not depend upon field fertiliza- tion, but should apply fertilizer directly to the pond. HANSEN et al.: Hook-ANp-LINE CatTcH 385 ECONOMICS OF POND FERTILIZATION Some pond owners will be interested in knowing whether the higher fish yields from fertilized ponds offset the cost of the fertilizers. At current (1960) prices quoted by dealers in farm fertilizers, the treatments used on the Dixon Springs ponds in 1947— 1949 would cost approximately $10 per surface acre of water per year; the various treatments used on the three ponds in 1950 would average close to $15 an acre, and the treatments used in 1951-1953 would cost $20 per acre per year. In the following computations, cost for fertiliz- ing the ponds does not include wages for men to do the mixing and spreading. For the 5-year period 1948-1952, the average annual hook-and-line yield (bass and bluegills combined) from the ferti- lized ponds was 48 pounds per acre and from the control ponds 25 pounds per acre, table 16. Although the fertilized ponds were fished somewhat more heavily than the controls, we will assume that most of the 23 pounds greater annual yield of the fertilized ponds was attrib- utable to fertilization. Dressed weights of bass and bluegills would amount to about two-thirds of their live weights. The 23 pounds additional fish yield would there- fore shrink to about 15 pounds in dress- ing. The average yearly cost for fertilizer over the 5 years, 1948-1952, was about $15 per acre; therefore the cost of the extra yield was approximately $1.00 per pound of dressed fish. Using data in table 16, we can make a similar computation for the same period for certain fertilized and unfertilized ponds having nearly equal fishing pres- sures: Lauderdale and Phelps to repre- sent the fertilized ponds, Wells and Boaz the untreated ponds. The total fishing pressure for the two fertilized ponds (164 hours per acre per year) was nearly the same as that for the two control ponds (157 hours per acre per year). The per- acre yield averaged +7 pounds annually from the two fertilized ponds, 28 pounds annually from the two controls, a differ- ence of 19 pounds as live fish or 13 pounds as dressed fish. Here the larger yield of the fertilized ponds was obtained 386 I_ttrinois NATURAL History SurvEY BULLETIN at a cost of about $1.15 per pound of dressed fish. Using selected data in table 15, we can compare costs for the periods of compara- tively light and comparatively heavy fer- tilizer treatments. In the following com- putations, we have omitted data for 1947, as before, and have also omitted data for 1950, when the three ponds were ferti- lized at three different rates. For 1948 and 1949, the annual yields from the fertilized ponds averaged 15 pounds per acre more than the yields from the con- trols—10 pounds in terms of dressed fish. Since the annual cost of fertilizer in 1948 and 1949 was about $10 per acre, the ad- ditional yield of dressed fish cost approxi- mately $1.00 per pound. For 1951 and 1952, the annual yield was 26 pounds greater per acre in the fertilized ponds than in the controls, or 17 pounds dressed weight. The cost of fertilizer during this period was about $20 an acre, making the cost of the additional yield approxi- mately $1.18 per pound of dressed fish. Also, we can estimate the cost per pound of fish attributed to fertilization in each of + years by comparing the rec- ords for Lauderdale and Wells, two ponds that were fished at nearly the same rates in most years, especially 1948-1951, and were fished in nearly the same way by the test anglers. As table 15 shows, the per- acre yield of bass and bluegills from Lauderdale was greater than that from Wells by 20 pounds in 1948, 17 pounds in 1949, 42 pounds in 1950, and 30 pounds in 1951. When we divide the ap- propriate cost figures, $10 an acre in 1948 and 1949, $20 an acre in 1950 and 1951, by the dressed weights (13, 11, 28, and 20 pounds), we find that the greater yields from Lauderdale Pond cost ap- proximately $0.77 a pound in 1948, $0.91 in 1949, $0.71 in 1950, and $1.00 in 1951. In the vicinity of Dixon Springs, the approximate retail price of dressed carp from the Ohio River is 25 cents a pound, of dressed channel catfish 60 cents a pound. If we were to judge the pond fertilization program at Dixon Springs solely by the dollar and cents food value of the fish produced, we should conclude that fertilization was not economically justified. Vol. 27, Art. 5 However, as a rule pond owners will not base their decisions to fertilize or not to fertilize their ponds solely on economic grounds. Instead, they will base such de- cisions largely on the belief that fertiliza- tion will or will not provide them and their families with more fishing fun. In some instances, the size of the pond, the type of ownership, and the financial position of the owner will influence the decision. For example, a pond of an acre or more might be left unfertilized and a pond of one-half acre might be fertilized, because the smaller pond requires a small- er outlay for fertilizer. A pond owned by a single individual might be left unferti- lized and an equivalent pond owned by a club might be fertilized, because the cost of the club-owned pond can be borne by several members and requires no great out- lay for any one individual. A pond might be left unfertilized if owned by a person who has a small cash income, or who fishes principally for food, and an equivalent pond might be fertilized if owned by an in- dividual who has a moderate or large cash income, or who fishes principally for sport. As the Dixon Springs experiment shows, ponds seem to differ in their responses to fertilization; fertilization might be eco- nomically profitable in some ponds but not in others. ANGLERS’ EVALUATION OF PONDS While we have shown that pond ferti- lization was of some benefit to bluegill fishing, there is a question whether the differences between fertilized and unfer-— tilized ponds in the quality of fishing were great enough to be detected by fishermen. No comments were heard or reported that would indicate that the permit fishermen thought that Hooker and Phelps (the two permit ponds that were fertilized) pro- vided them with better fishing than the unfertilized permit ponds or other unfer- tilized ponds in the neighborhood. The test anglers, who visited all six ponds at weekly intervals, generally had the most success at Lauderdale Pond. Their pref- erences were recorded only after the 1952 fishing season, but it was obvious from our — conversations with them that Lauderdale ~ was the favorite among the six ponds. August, 1960 Charles R. Peters, test angler in 1952, stated that Lauderdale had given him the most pleasure, and he rated the other ponds in the following order: Elam, Phelps, Wells, Boaz, and Hooker. Thus, he ranked the fertilized ponds first, third, and sixth. Examination of his catch rec- ords suggests that his reaction to various ponds might have been affected more strongly by his success in catching bluegills than by his success in catching bass. Use by the public was somewhat more intensive for the two permit ponds that were fertilized (Hooker and Phelps— especially Hooker) than for the two that were not (Boaz and Elam), table 20. It seems doubtful, however, if catch rates were enough higher for the fertilized ponds to explain their greater popularity with fishermen. Hooker and Phelps ponds were seldom as good as the unfertilized ponds for bass fishing and in some years were not so good as one or more unferti- lized ponds for bluegill fishing. “Time spent by permit fishermen in the 6 years of the experiment totaled 92+ hours at Hooker, 374 hours at Phelps, 356 hours at Boaz, and 217 hours at Elam. The 6- year average catch-per-man-hour rate for bass in the most heavily fished fertilized pond (Hooker) was below the rate for the least fished control pond open to the public (Elam). The bluegill fishing in Hooker was inferior to that in Elam in terms of number of fish per hour but essentially the same in pounds per hour. The differences in fishing pressure on the four permit ponds may have been re- lated to the various inconveniences fisher- men put up with in getting to and from each pond, such as the number of gates to be opened and closed, the number of fences to be climbed, or the walking dis- tance to the pond. Hooker Pond was the easiest to reach, Elam Pond the most dif- ficult. The inconveniences of reaching Phelps and Boaz were about equal. Quite possibly the availability of shade, ease of walking around the ponds, and general attractiveness of the ponds were factors that made the fishermen decide to fish certain ponds more often than others. Fishermen were not guided to the ferti- lized ponds by news releases or other publicity; only a few of them knew that some ponds were being treated. HANSEN et al.: HooK-ANpD-LINE CATCH 387 SUMMARY 1. Six ponds, each of about 1-1% acres, in southern Illinois were used in an experiment, 1947-1952, to measure the ef- fect of pond fertilization on sport fishing. The effect of fertilization was measured by the sizes of the fish caught, the annual hook-and-line yields, and the catch rates per fisherman-hour. 2. The ponds were stocked with large- mouth bass 6 to 10 inches long (total length) and bluegills about 1 inch long. 3. Three of the ponds were treated with chemical fertilizers containing nitro- gen, phosphorus, and potassium, in some years at rates less than, and in others at rates approximately equal to, the mini- mum rate suggested for ponds in Alabama by Swingle & Smith (1942:16-8). The other three ponds (the controls) were not treated. 4. Creel data were obtained through (1) public fishing under a permit system that allowed fishermen relatively free ac- cess to four of the ponds and (2) test fishing by anglers (one each year) em- ployed by the Illinois Natural History Survey to fish each of the six ponds for a 2-hour period each week. 5. In 1953, after the ponds had been closed to fishing for a year, the fish in all six ponds were killed with rotenone, and a census was made of the fish population of each pond. 6. Growths of filamentous algae, which appeared on the fertilized ponds in some years, were at times a hindrance to fisher- men. 7. Dense stands of a water plant, Chara spp., died in the fertilized ponds in the first summer of treatment, while equal- ly dense stands of this plant continued to grow in the control ponds. 8. Blooms of plankton algae were den- ser and more prolonged in the fertilized than in the control ponds. 9. The bass taken from the fertilized ponds averaged smaller but the bluegills larger than those from the control ponds. Bluegills of 8-8'™% inches were more com- mon from fertilized than from unferti- lized ponds. 10. During the 5 years of fishing for both bass and bluegills (in the year after the ponds were stocked, bluegills were too 388 small to be kept), the total harvest of bass, by weight, was slightly less from the fertilized ponds than from the controls; the bluegill harvest from the fertilized ponds was 2.7 times that from the con- trols. The ratio by weight of bass to blue- gills was 1:3 in the fertilized ponds, 1: 1 in the controls. 11. One of the fertilized ponds was superior to all others in both bass and bluegill fishing. The three fertilized ponds ranked 1, 5, and 6 in terms of both num- ber and weight of bass harvested per hour; 1, 3, and 4 in terms of number of bluegills harvested per hour; and 1, 2, and 3 in terms of weight of bluegills harvested per hour. 12. There is a statistical possibility that through chance alone the fertilized ponds would have ranked better than the controls as bluegill fishing ponds even if no fertilizer had been used. 13. No well-defined year-to-year trend in catch rates for bass was observed dur- ing the experiment. The trend in bluegill fishing in both fertilized and control ponds was toward year-to-year improvement in the first + years of bluegill fishing. 14. The two ponds, one fertilized and one control, with the smallest total num- ber of man-hours of fishing had the highest catch rates of harvestable bass. Under equal or nearly equal fishing pressures, bass fishing was in some instances better in the fertilized ponds, in other instances better in the controls; bluegill fishing was consistently better in the fertilized ponds. 15. In September, 1953, the standing crops of bass and bluegills (all sizes) in the three fertilized ponds averaged 292 pounds per acre, in the three controls 238 pounds per acre (ratio 1.2:1). The num- Ittrnors NATURAL History SurvEY BULLETIN Vol. 27, Art. 5 ber of bass 10 inches or longer was ap- proximately the same in fertilized as in control ponds; the number of bluegills 6 inches or longer was 1.3 times as great in fertilized as in unfertilized ponds. 16. The hook-and-line yields of bass and bluegills in 1952, the last year the ponds were fished, were equivalent to 20 per cent of the 1953 standing crops in the fertilized ponds and 16 per cent of the standing crops in the control ponds. 17. Judged by the populations of fish of desirable sizes present at the time of the 1953 census (bass 10 inches or longer, bluegills 6 inches or longer), the hook- and-line harvest appears to have been more efficient for bass in the control ponds and more efficient for bluegills in the fer- tilized ponds. 18. Surprisingly little correlation was found between numbers of bass and blue- gills of harvestable sizes in the ponds in 1953 and the record of fishing success in the preceding years. 19. The fertilization program used at Dixon Springs was of apparent benefit to bluegill fishing but of doubtful benefit to bass fishing; any benefits derived from direct fertilization of ponds were in ad- dition to benefits that may have resulted from fertilization of the pond watersheds. 20. Comparison of yields from the fertilized and unfertilized ponds at Dixon Springs shows that the greater yields of fish from the fertilized ponds were ob- tained at costs estimated to range from $0.71 to $1.18 a pound. 21. Whether the improvement in the quality of bluegill fishing attributed to fertilization was great enough to be de- tected by fishermen is questionable for at least two of the three fertilized ponds. PETE RAST OOOR BE CLhEE D Ball, Robert C. 1948. Recovery of marked fish following a second poisoning of the population in Ford Lake, Michigan. Am. Fish. Soc. Trans. for 1945, 75:36—42. 1949. Experimental use of fertilizer in the production of fish-food organisms and_ fish. Mich. State Col. Ag. Exp. Sta. Tech. Bul. 210. 28 pp. Ball, Robert C., and Don W. Hayne 1952. Effects of the removal! of the fish population on the fish-food organisms of a lake. Ecology 33(1) : 41-8. Ball, Robert C., and Howard D. Tait 1952. Production of bass and bluegills in Michigan ponds. Mich. State Col. Ag. Exp. Sta. Tech. Bul. 231. 32 pp. Ball, Robert C., and Howard A. Tanner 1951. The biological e%ects of fertilizer on a warm-water lake. Mich. State Col. Ag. Exp. Sta. Tech. Bul. 223. 32 pp. Bennett, George W., and Gilbert F. Weiss 1959. Fishing pressure and the empty creel. Ill. Wildlife 14(3) : 8-9. Brown, C. J. D., and Robert C. Ball 1943. An experiment in the use of derris root (rotenone) on the fish and fish-food organisms of Third Sister Lake. Am. Fish. Soc. Trans. for 1942, 72:267-84. Carlander, Kenneth D., and William M. Lewis 1948. Some precautions in estimating fish populations. Prog. Fish-Cult. 10(3) : 134-7. Davis, H. S., and A. H. Wiebe 1931. Experiments in the culture of the black bass and other pondfish. Report of the United States Commissioner of Fisheries for the fiscal year 1930, Appendix IX:177-203. (U. S. Bur. Fish. Doc. 1085.) Dugan, R. Franklin 1951. Fish production records on some West Virginia farm ponds. N. Am. Wildlife Conf. Trans. 16:403-21. Fehrenbacher, J. B. 1959. Characteristics of the soils on the Dixon Springs Experiment Station of the University of Illinois College of Agriculture. Ill. Univ. Agron. Dept. Mimeo. AG1841. 5 pp., map. King, Willis 1943. Lake management studies in the Sandhills Wildlife Management Area. Am. Fish. Soc. Trans. for 1942, 72:204-11. Krumholz, Louis A. 1948. Variations in size and composition of fish populations in recently stocked ponds. Ecol- ogy 29(4) : 401-14. 1950a. Some practical considerations in the use of rotenone in fisheries research. Jour. Wild- life Mgt. 14(4) : 413-24. 1950. Indiana ponds: their construction and management for fishing. Lake and Stream Sur- vey of the Indiana Department of Conservation, Division of Fish and Game, and In- diana University. (Ind. Univ. Zool. Dept. Contrib. 435.) 35 pp. Maciolek, John A. 1954. Artificial fertilization of lakes and ponds: a review of the literature. U. S. Fish and Wildlife Scrv. Special Sci. Rep.: Fish. 113. 41 pp. Mortimer, C. H., and C. F. Hickling 1954. Fertilizers in fishponds: a review and bibliography. Her Majesty’s Stationery Office, London. Colonial Office Fish. Pubs. 5. 155 pp. Neess, John C. 1949. Development and status of pond fertilization in central Europe. Am. Fish. Soc. Trans. for 1946, 76:335-58. Patriarche, Mercer H., and Robert C. Ball 1949. An analysis of the bottom fauna production in fertilized and unfertilized ponds and its utilization by young-of-the-year fish. Mich. State Col. Ag. Exp. Sta. Tech. Bul. 207. 35 pp. Schaeperclaus, Wilhelm 1933. Textbook of pond culture: rearing and keeping of carp, trout and allied fishes. (Trans- lated from the German by Frederick Hund.) U. S. Fish and Wildlife Serv. Fish. Leaflet 311. 260 pp. Smith, E. V., and H. S. Swingle 1939. The relationship between plankton production and fish production in ponds. Am. Fish. Soc. Trans. for 1938, 68:309-15. [ 389 ] 390 Intinois NATuRAL History Survey BULLETIN Vol. 27, Art. 5 1942. The use of fertilizer for controlling several submerged aquatic plants in ponds. Am. Fish. Soc. Trans. for 1941, 71:94-101. Smith, Lloyd L., Jr., and John B. Moyle 1945. Factors influencing production of yellow pikeperch, Stizostedion vitreum vitreum, in Minnesota rearing ponds. Am. Fish. Soc. Trans. for 1943, 73:243-61. Smith, M. W. 1952. Fertilization and predator control to improve trout production in Crecy Lake, New Brunswick. Can. Fish Cult. 13:33-9. 1954. Planting hatchery stocks of speckled trout in improved waters. Can. Fish Cult. 16:1-5. Surber, Eugene W. 1945. The effects of various fertilizers on plant growths and their probable influence on the production of smallmouth black bass in hard-water ponds. Am. Fish. Soc. Trans. for 1943, 73:377-93. 1948a. Fertilization of a recreational lake to control submerged plants: effects of fertilization program upon bathing, boating, fishing. Prog. Fish-Cult. 10(2) :53-8. 1948b. Increasing production of bluegill sunfish for farm pond stocking. Prog. Fish-Cult. 10(4) :199-203. Swingle, H. S. 1945. Improvement of fishing in old ponds. N. Am. Wildlife Conf. Trans. 10:299-308. 1947. Experiments on pond fertilization. Ala. Poly. Inst. Ag. Exp. Sta. Bul. 264. 34 pp. Swingle, Homer S., and E. V. Smith 1941. The management of ponds for the production of game and pan fish. Pp. 218-26 in A symposium on hydrobiology. University of Wisconsin Press, Madison. ix +405 pp. 1942. Management of farm fish ponds. Ala. Poly. Inst. Ag. Exp. Sta. Bul. 254. 23 pp. Thompson, David H. 1941. The fish production of inland streams and lakes. Pp. 206-17 in A symposium on hydro- biology. University of Wisconsin Press, Madison. ix + 405 pp. Thor, A. U., and W. C. Jacob 1955. Percentage of soil samples by counties testing very low, low, slight, medium, high, and very high in Illinois, 1955. Ill. Univ. Agron. Dept. Mimeo. AG1750a. 4 pp. Zeller, Howard D. 1953. Nitrogen and phosphorus concentrations in fertilized and unfertilized farm ponds in central Missouri. Am. Fish. Soc. Trans. for 1952, 82:281-8. t * ik eG) wa Some Publications of the Ittrnois NaTurRAL History Sunvey BULLETIN Volume 26, Article 3.—Natural Availability of Oak Wilt Inocula. By E. A. Curl. June, 1955. 48 pp., frontis., 22 figs., bibliog. Volume 26, Article 4.—Efficiency and Selec- tivity of Commercial Fishing Devices Used on the Mississippi River. By William C. Starrett and Paul G. Barnickol. July, 1955. 42 pp., frontis., 17 figs., bibliog. Volume 26, Article 5.—Hill Prairies of LIIli- nois. By Robert A. Evers. August, 1955. 80 pp., frontis., 28 figs., bibliog. Volume 26, Article 6.—Fusarium Disease of Gladiolus: Its Causal Agent. By Junius L. Forsberg. September, 1955. 57 pp., frontis., 22 figs., bibliog. Volume 27, Article 1.—Ecological Life History of the Warmouth. By R. Weldon Larimore. August, 1957. 84 pp., color frontis., 27 figs., bibliog. Volume 27, Article 2—A Century of Biological Research. By Harlow B. Mills, George C. Decker, Herbert H. Ross, J. Cedric Carter, George W. Bennett, Thomas G. Scott, James S. Ayars, Ruth R. Warrick, and Bessie B. East. December, 1958. 150 pp., 2 frontis., illus., bibliog. $1.00. Volume 27, Article 3—Lead Poisoning as a Mortality Factor in Waterfowl Populations. By Frank C. Bellrose. May, 1959. 54 pp., frontis., 9 figs., bibliog. 50 cents. Volume 27, Article 4—Food Habits of Migra- tory Ducks in Illinois. By Harry G. Ander- son. August, 1959. 56 pp., frontis., 18 figs., bibliog. 50 cents. CIRCULAR 42.—Bird Dogs in Sport and Conservation. By Ralph E. Yeatter. December, 1948. 64 pp., frontis., 40 figs. 48.—Diseases of Wheat, Oats, Barley, and Rye. By G. H. Boewe. June, 1960. 157 pp., frontis., 56 figs. Single copies free to Illinois resi- dents; 25 cents to others. List of available publications mailed on request. Single copies of ILL1nois NATURAL History SurveY publications for which no price is li will be furnished free of charge to individuals until the supply becomes low, after nominal charge may be made. More than one copy of any free publication may be c without cost by educational institutions and official organizations within the State of prices to others on quantity orders of these publications will be quoted upon request. Address orders and correspondence to the Chief, Itttnois NA History Survey, Natural Resources Building, Urbana, Illinois BIOLOGICAL NOTES 33.—A New Lbmgeiy in Control of elt Ho Fly. By Willis N. Bruce. December 8 pp., 5 figs. ie $4,—White-Tailed Deer Populations in nois, By Lysle R. Pietsch. June; 1954, pp., 17 figs., bibliog. 35—An Evaluation of the Red Thomas G. Scott. July, 1955. printing.) 16 pp., illus., bibliog. 36.—A Spectacular Waterfowl Through Central North America. E C. Bellrose. April, 1957. 24 pp. 9 i liog. 37.—Continuous Mass Rearing of tl pean Corn Borer in the Labors Paul Surany. May, 1957. 12 pp., bibliog. 38.—Ectoparasites of the Cottontail Lee County, Northern Illinois. By Lew Stannard, Jr., and Lysle R. Pietsch. J 1958. 20 pp., 14 figs., bibliog. £ 39.—A Guide to Aging of Pheasant By Ronald F. Labisky and James F. September, 1958. 4 pp., illus., bib 40.—Night-Lighting: A Technique | turing Birds and Mammals. By Re Labisky. July, 1959. 12 pp., 8 figs., 41—Hawks and Owls: Population From IIlinois Christmas Counts. By | R. Graber and Jack §. Golden. Manan 24 pp., 24 figs., bibliog. 42.—Winter Foods of the Bobwhite in § Illinois. By Edward J. Larimer. 36 pp., 11 figs., bibliog. MANUAL 3.—Fieldbook of Native Illinois suru’ Leo R. Tehon, December, 1942. 3( ee 4 color pls., 72 figs., glossary, index. $1 4.—Fieldbook of Illinois Mammals. By Do F. Hoffmeister and Carl O. Mohr. sary, bibliog, index. $1.75. _ sige ba: Payment in the form of money order or check made out to State Treasurer of | li Springfield, Illinois, must accompany requests for those publications on which a price i is: ILLINOIS NATURAL HISTORY SURVEY Bulle tin Printed by Authority of Ke - the State of Illinois Sex Ratios and Age Ratios in North American Ducks FRANK C. BELLROSE THOMAS G. SCOTT ARTHUR S. HAWKINS JESSOP B. LOW STATE OF ILLINOIS Orro Kerner, Governor DEPARTMENT OF REGISTRATION AND EDUCATION WILiiaM SyLvester Wuire, Director _ NATURAL HISTORY SURVEY DIVISION Hartow B. Mus, Chief NATURAL PO i es hi UWIOTADYV Gitrncure ILLINOIS NATURAL HISTORY SURVEY Bulletin Volume 27, Article 6 rr Printed by Authority of August, 1961 the State of Illinois Sex Ratios and Age Ratios in North American Ducks meANK C. BELLROSE maAONMAS G. SCOTT me PHUR S. HAWKINS aero) P B. LOW Beer AG neh Ou lel I N-OoLss Otto KERNER, Governor DEPARTMENT OF REGISTRATION AND EDUCATION WILLIAM SYLVESTER WHITE, Director NATURAL HISTORY SURVEY DIVISION Hariow B. MI ts, Chief Urbana, Illinois STATE OF ILLINOIS Orro Kerner, Governor DEPARTMENT OF REGISTRATION AND EDUCATION Wituram Sytvester Waite, Director BOARD OF NATURAL RESOURCES AND CONSERVATION Wituam Sy.vesteR Waite, Chairman; A. E. Emerson, Ph.D., Biology; Watter H. Newnouse, Ph.D., Geology; Rocer Apams, Ph.D., D.Sc., Chemistry; Rosert H. Anperson, B.S.C.E., Engineering; W. L. Everitt, E.E., Ph.D., Representing the President of the University of Illinois; Detyte W. Morris, Ph.D., President of Southern Illinois University NATURAL HISTORY SURVEY DIVISION, Urbana, Illinois SCIENTIFIC AND TECHNICAL STAFF Hartow B. Mitts, Ph.D., Chief Bessie B. East, M.S., Assistant to the Chief Section of Economic Entomology Georce C. Decker, Ph.D., Principal Scientist and Head J. H. Biccer, M.S., Entomologist L. L. Encuisu, Ph.D., Entomologist W. H. Luckmann, Ph.D., Entomologist Wits N. Bruce, Ph.D., Entomologist ; Joun P. Kramer, Ph.D., Associate Entomologist Ricwarp J. Dysart, Ph.D., Associate Entomologist Ronatp H. Meyer, M.S., Assistant Entomologist Recinatp Roserts, M.S., Technical Assistant James W. Sanrorp, B.S., Technical Assistant Eart STADELBACHER, B.S., Technical Assistant Wittiam C. Moye, M.S., Technical Assistant Sve E. Warxins, Technical Assistant H. B. Perry, Ph.D., Extension Specialist in Entomology* Stevenson Moore, III, Ph.D., Extension Specialist in Entomology* Zenas B. Noon, Jr., M.S., Research Assistant* Ciarence E. Wuire, B.S., Instructor in Entomology Extension* Costas Kousxorexas, M.S., Research Assistant* Amat CHanpra Banerjee, M.S., Research Assistant* Victor T. Wiiutams, B.S., Research Assistant* Section of Faunistic Surveys and Insect Identification H. H. Ross, Ph.D., Principal Scientist and Head Mirron W. Sanverson, Ph.D., Taxonomist Lewis J. Srannarp, Jr., Ph.D., Taxonomist Puitie W. Situ, Ph.D., Associate Taxonomist Leonora K. Guroypv, M.S., Assistant Taxonomist H. B. Cunnincuam, M.S., Assistant Taxonomist Rurn P. Casu, Technical Assistant Joun M. Krncsotver, Ph.D., Research Associate Epwarp O. Mout, Research Assistant Joun D. Unzicxer, Research Assistant Tataat K. Mirri, M.S., Research Assistant* Section of Aquatic Biology Georce W. Bennett, Ph.D., Aquatic Biologist and Head Wituiam C. Srarrett, Ph.D., Aquatic Biologist R. W. Larimore, Ph.D., Aquatic Biologist Davw H. Buck, Ph.D., Associate Aquatic Biologist Rosert C. Hirtipran. Ph.D.. Associate Biochemist Donautp F. Hansen, Ph.D., Associate Aquatic Biologist Wiiiiam F. Cuitpvers, M.S., Assistant Aquatic Biologist Marirran Martin, Technical Assistant Rosert D. Crompton, Field Assistant Rotiw D. Anprews, III, B.S., Field Assistant Larry S. Goopwin, Laboratory Assistant Daviv J. McGinty, Field Assistant* Section of Aquatic Biology—continued Cuartes F. Tuorrs, Ill, A.B., Field Assistant* Section of Applied Botany and Plant Pathology J. Cepric Carrer, Ph.D., Plant Pathologist and Head J. L. Forsperc, Ph.D., Plant Pathologist G. H. Boewe, M.S., Associate Plant Pathologist Ropert A. Evers, Ph.D., Associate Botanist Ropert Dan NeeExy, Ph.D., Associate Plant Pathologist E. B. Himenicx, Ph.D., Associate Plant Pathologist Water Harrstirn, Ph.D., Assistant Plant Pathologist D. F. Scnoreneweiss, Ph.D., Assistant Plant Pathologist Anne Ropinson, M.A., Technical Assistant Section of Wildlife Research Tuomas G. Scorr, Ph.D., Wildlife Specialist and Head Raupu E. Yeatrer, Ph.D., Wildlife Specialist F. C. Bexirose, B.S., Wildlife Specialist H. C. Hanson, Ph.D., Associate Wildlife Specialist Ricuarp R. Graser, Ph.D., Associate Wildlife Specialist Ronatp F. Lasisxy, M.S., Associate Wildlife Specialist Guren C. Sanverson, M.A., Associate Wildlife Specialist Marjorie J. Scuuatrer, Technical Assistant D. G. Rose, B.S., Technical Assistant Howarp Crum, Jr., Field Assistant Rexrorp D. Lorp, D.Sc., Project Leader* Jack A. Exxuis, M.S., Project Leader* Bossie Jor Verts, M.S., Project Leader* Ratpeuw J. Exris, M.S., Project Leader* Wituiam L. Anperson, B.S., Assistant Project Leader* James A. Harper, M.S., Assistant Project Leader* Davi A. CasteeL, B.S., Assistant Project Leader* GeraLtp G. Montcomery, M.S., Research Associate* P. J. Rao, B.V.Sc., M.A., Research Assistant* Ann C. V. Houmes, B.S., Research Assistant* T. U. Meyers, Research Assistant* Sruart H. Mann, B.S., Research Assistant* Ricuarp W. Lurz, M.W.M., Research Assistant* Ricuarp D. Anprews, M.S., Field Mammalogist* Keirn P. Daupuin, Assistant Laboratory Attendant* Section of Publications and Public Relations James S. Ayars, B.S., Technical Editor and Head Buancue P. Younc, B.A., Assistant Technical Editor Epwarp C. Visnow, M.A., Assistant Technical Editor Witmer D. Zenr, Assistant Technical Photographer Technical Library Rutn R. Warrick, B.S., B.S.L.S., Technical Librarian Nett Mires, M.S., B.S.L.S., Assistant Technical Librarian CONSULTANTS: Herretorocy, Hosart M. Situ, Ph.D., Professor of Zoology, University of Illinois ; Parasiroocy, Norman D. Levine, Ph.D., Professor of Veterinary Parasitology and of Veterinary Research, University of Illinois; Witpuire Researcu, Witrarp D. Kuimstra, Ph.D., Professor of Zoology and Director of Co-operative Wildlife Research, Southern Illinois University. *Employed on co-operative projects with one of several agencies: University of Illinois, Illinois Agricultural Extension Service, Illinois Department of Conservation, National Science Foundation, United States Department of Agriculture, United States Fish and Wildlife Service, United States Public Health Service, and others. This paper is a contribution from the Section of Wildlife Research. (08324—6 M—10-60) a 2 Nor FOREWORD | ee present publication illustrates again the importance of continuing certain types of research over a long period of time in order to get data which allow for significant deductions to be made. Further, as the investigation reported here is in a sense pioneering work, much thought has had to go into data analysis, into weighing the importance of data, and into attempts to find the significance and relative importance of the many facts discovered. These opera- tions have necessitated the delay of publica- tion until it was felt that the data and con- clusions could withstand the inspection of waterfowl scientists and other biologists and, more importantly, contribute signifi- cantly to our understanding of North Ameri- can waterfowl. Certainly, the analysis of the data and the developing of the philosophy of the place of sex ratios and age ratios in population me- chanics was not an easy task; the data have been about as abstruse as any collected in waterfowl research. The project was conceived by Arthur S. Hawkins in 1938, while he was employed by the Illinois Natural History Survey, and great credit for far-sightedness must go to him. It must be remembered that, at the time of the project’s initiation, even good aging techniques were still to be perfected. When Mr. Hawkins entered the armed forces in 1941, Mr. Bellrose took over the study. Dr. Low contributed to the project in Illinois from 1941 to 1943 and furnished Utah data after he left Illinois. Through the last 20 years, Mr. Bellrose has carried the brunt of the load, and in re- cent years Dr. Scott has contributed im- measurably to data analysis and the prepara- tion of the study for publication, as well as arranging with the National Science Foun- dation for the financing of publication costs. Others, mentioned in the text, have given unselfishly of their time and talents. Last, but by no means least, we should mention the long hours—often extending into the night—spent by James S. Ayars, Tech- nical Editor, in working with the authors and the data. His was, as usual, a heavy and significant contribution. It is my hope, as well as that of the au- thors, that this contribution will be of value in the understanding and the management of waterfowl populations over a wide area and for a long time to come. Hartow B. Mitts, Chief Illinois Natural History Survey Urbana, Illinois Trapping and banding ducks at the Chautauqua National Wildlife Refuge near Havana, Illinois, November, 1939, CON TEN TS BEeEOWLENDGMENTS AND SOURCES OF Dara’. fi. 0.0. Tj cncscens wane Obes endeeeua- 391 METER ets rete yrs he die eae vk ver UREA, OE RA aa oO ee ee 392 Mere yee USEC CEGA(T: SEVICLES Vos) 3 af elcteieiood wack Eas apes ohh wc cle Snes 393 eM ESD hn tM C9 ANG 9 PE crery ds Shas DE Ue Sk De eo ee ee 394 rimemrenniations for Sex Watios: «2s 65.45. mcs osoec bE olin oR Ue 396 mrammeation, oink tapped Duke yy. is. Da. Peele ses siaoas a8 «sa tees one EP EE EL MaOL La Ute © BARS 4 hy. asthe aes’ ok Woe AE ee eee 400 Re ME SCR UUEIONGS © 0i.0 0 RMR toa Telok ee hele ye See 401 peerattrerinin OF Wisease, VichIMIs: :s/:. 00 Vio... d5e Che os ne oe nee See ee 402 eereememn Oitterent, Age “Classes... oo .adis a eidios boo v4 ee Dee See 402 MERE TERMS ORT IR AOS MySite ote Pile uk Ga Mia aii at POM cel cae oR ea 402 eR eRMES ER TEC LERIVS OPE 0s Sd co, wi Sh UA oe, ve ee A EL 403 (BT TRESS ys 20 ES eno aa Rn SR ne vee SP 403 rea TINS MAAS y : 6 51 adrace Balog de Cag OS aioe Se Us wk i ee 405 Peer ar Aations stile Sex RALOSs sc ida. .'e5.¢0 sees calaic yee vl 4 ane Peace ores 408 Pee ee ese iE Akl ttal VV IMECL <<< Gordo atic ake « Sota ek Sona FE oc oe NA ee 408 Cy SUE ERPS AT a LN rol Dv or ag i mc POR gee Oe 411 Mombanesunuthe Isteeding Seasons << 2.6.4.0. ces vs twee k eae oe ORE e een 416 SPeUreM NN TEIAtIOnS I. SEX RATIOS. ¢ 20004. <'% 2c os eau wuha woe ss sv oath eeetas 419 Mima actors Affectino sex Ratios...... 0... 6ceccs'etscess basesecueeanee es 420 Se MOMRAMUTO ME ANIMES LS 2). 8c 6 ETE pea, Pack bale w ha icthew Beas. 3 Rd ek 5 TM 421 et ere REIT OS eed chs Shanice 6 dye ces ween a hk PA Rae edie atiocs he ee 421 ) TEGIEOS HIS MO7a 1a. Ploy es e222 (10 Cy ean gn eA Dea a oe 424 Pememirural ©perations and Sex Ratios ss... 4.46 cs. 4. is cas dee wetin es eenees 425 et ANE LEIOS). fcc aiercig 5 o.34s he Aaaoh SULA ee SDA ao Me PER lt eee 425 Paat OTA WV UOLEALLCY, a ACEOES.. a istcsn es sade cs 4m lee ahah ee = Belen, we ae bene 426 pueeeatios and Age Composition of Populations........<0....6..0ceeecscneaees 426 Meera vot surplus Drakes. oo o..< Sal sfed oa oe g he ebs vow avs obuule a Mate te 427 Beweieatins as. \Vieasures of Production 2%... sc0cc 5) eb ecb ae ee ols oe oer ee ed 428 RTE 2 S'S ES 8 ea EP OS ners ge eed rane nS ere Seah ee 2 430 Bee CHAE AP ye at Ha ed cS of os ae shins eaa = al -as lax nue a Ger ale Raced al muslin Makate e 430 Si eR EN? RULER VAS Re 0 aN fc Sad yO Ae cP eal nes Fo -6 ond a wee ae vias RE ee 431 Peeoomnatians ot Erappen DUCKS... ein sane ne 'n 06 ue dns teaa eee oe ee eer ee 431 Menocciian “ole biinters BAGS sac «oe oc io' nice aceionia is nav v5.8 50 8 Ro ane Doe aans eo 435 Pier a pranhOs LONSEASE. NW ICEIENS cca, «or <:k tos vravagalo Oa Scam Cordele Makan ee 439 Nessie ariations’ in’ ee KMatlOSs oslo. gels voor eot ge been wees UM Ea ets 440 eemimaley Atiations. it AoE! RACIOS 5, \'ueerte 4+ Sr0e< 2 Sfo's @ ayaie Dale niece eee ae 444 Par Ml eens ek ele sce tie aT Ee LOE RENE a RN a nk aN ee aes ee a eae 444 MOE ie HENLE pee an <9 hel w oie! Sno avahe one bree IRD ENDS re gueneee eee ae a 447 PURI RES AY Pet UOs NOC), IRABLOS vps die ic-c:< 5, dba eens te olor seig ee roto eee a ETS eaeae eee 449 ee rs ved ale ie ts tna! un acne ol es chats bb ayicte ve tate dustin MONE eke okieans anise nao 451 Defoe 9 82 | a, a ae Or eR oP ere Re nate Shee ne 451 olmrea pean Pot Mein va, 2 Seg ee sles ap wic ents ao ks es ee eae rama ate 451 Aaceeatinsas Wieasures ot PFOGUCLION:. <5 6.6 6.cc< viet ered oncclene ene scelaere ety ryes ft 454 Pedauetione Andee nV ITONiient is + 22.7 WeSSE6 BCAUDE ts crce sere eats 468 46.4.NS 310 6651 ~ > + 19.7 ALN SPECIES soto Sw NOCR Ce Ne 4 14,583 50.8 NS 5,101 50 6.0 NS = Not a significant departure from 50 per cent at the 0.05 probability level. *Significant departure from 50 per cent at the 0.05 probability level. **Significant departure from 50 per cent at the 0.01 probability level. August, 1961 more drakes than hens in the samples, ta- bles 13 and 14. Records on 9,725 adult mallards over a period of 12 years, 1939— 1950, revealed an average of 65.7 per cent drakes, with annual percentages ranging from 58.5 to 68.7 per cent; rec- ords on 11,637 adult mallards for a pe- riod of 18 years, 1939-1955 and 1959, re- vealed an average of 65.2 per cent drakes, with annual percentages ranging from 58.5 to 70.8, table 13. The adult class of nine other species of ducks in hunters’ bags over an Il-year period, 1939-1949, con- tained 61.4 per cent drakes; annual per- BELLROSE et al.: SEX RATIOS AND AGE RaTIOS 407 centages ranged from 70.6 per cent drakes for the black duck to 51.0 per cent drakes for the ring-necked duck, table 14. Statistical analysis of data compiled from the inspection of adult mallards, gadwalls, baldpates, pintails, green- winged teals, shovelers, and redheads in hunters’ bags in Utah over a period of 6 years, 1943-1944 and 1946-1949, table 18, revealed a highly significant greater number of drakes than hens for all spe- cies excepting the redhead. Data from the Mississippi Flyway for 3 years, 1946-1948, tables 15-17, indi- Table 17.—Drake percentages in ducks of 11 species, juvenile and adult classes, checked in hunters’ bags in the Mississippi Flyway, 1948. JuveENILEs ADULTS DIFFERENCE BETWEEN SPECIES ADULT (+) AND Number Per Cent Number Per Cent JuveniLe (—) Checked Drakes Checked Drakes PERCENTAGES Jail nil 9p a5 5 eee eee asics 7,416 SP one 2,556 Som Ome + 5.5 PA CKMGUCK. Secale oie. s atslele wees 871 47.2 NS 378 SO} + 11.8 acliyalll tb aolaig earth eeeiee eae 214 53.7 NS 31 58.0 NS + 4.3 Palle ORS: Ae teed ee ener 1,068 49.5 NS 141 50.3 NS + 0.8 RTE PE Se oe caion0 ta ious. arene TPT 51.8 NS 216 56.5 NS + 4.7 Green-winged teal.......... 493 550" 130 49.2 NS — 6.4 Blue-winged teal........... 255 47.5 NS 63 S0euse — 17.4 Be dNCAC Ra cei oe ess aos 680 46.6 NS 82 51.2 NS + 4.6 Ring-necked duck.......... 336 48.2 NS 66 56.0 NS + 7.8 BRAS DAGKS 2.2. Se cece 410 500.3 520 48.5 NS 66 43.9 NS — 4.6 BRESSEEISCAUID © Se csccciecs.css vious 547 49.2 NS 186 Moke? + 18.5 PHIESDECLES of. Fisve’o)c ovens soo bes. 0.8 13,127 51.2 NS SL O15: iSrileae 6.9 NS=Not a significant departure from 50 per cent at the 0.05 probability level. *Significant departure from 50 per cent at the 0.05 probability level. **Significant departure from 50 per cent at the 0.01 probability level. Table 18.—Drake percentages in ducks of seven species, juvenile and adult classes, checked in hunters’ bags in Utah, 1943, 1944, and 1946-1949. JUVENILES ADULTS DIFFERENCE BETWEEN Apu tT (+) SPECIES Number | Per Cent | Number | Per Cent AND Checked Drakes Checked Drakes | JUVENILE (—) PERCENTAGES a ere 2,027 | 52.3* 2,350 | 62.3** | + 10.0 erly ll meer sp ree ae ai cicbaras ted ale verasepake 1,679 joe me 1955 (Ws + 14.2 ville (Ne) a canst RO Re aie Rae eee eae Diy) 522s 1,183 6lesee + 9.3 BAe AT Meee y eet oti tare ois ey tuace ard lel «tte ye 4,230 46 .8** 6,499 Bh (Sie + 6.8 Picech-winged teal.................. 2,828 Se Ome 4,183 Tonge + 14.9 | FE ig Se es 2,480 Ey liga 1,674 65.07" + tls9 BEE ICAGIUPE NS cre io timate ane Sie oke aie ees 734 See 214 48.6 NS — 8.7 NE SRGHIOT sR e GOO OE DI SEO one ore 16,330 Se oe 18,058 O2n5nn 9.9 NS=Not a significant departure from 50 per cent at the 0.05 probability level. *Significant departure from 50 per cent at the 0.05 probability level. **Significant departure from 50 per cent at the 0.01 probability level. 408 cate that adult drakes consistently, but not in all cases significantly, outnumbered adult hens in hunters’ bags for mallards, black ducks, gadwalls, baldpates, pin- tails, and lesser scaups. By contrast, the records show that hens were more nu- merous than drakes among the blue- winged teals and shovelers inspected, and year-to-year variation was evident in sex ratios among green-winged teals, redheads, ring-necked ducks, and canvasbacks. Ta- bles 15-17 indicate the statistical signifi- cance of the departure of these sex ratios from balanced sex ratios. Seasonal Variations in Sex Ratios Sex ratios for many species of ducks were found to vary from week to week in any given area as the composition of the local population changed with arrival and departure of flocks containing varying numbers of drakes and hens. The sea- sonal changes in sex ratios were ascer- tained through data obtained from trap- ping, inspection of hunters’ bags, field ob- servation, and tallies of victims of disease. Sex Ratios in Fall and Winter.— The sex ratios of the most important spe- cies of ducks taken by hunters during the fall hunting season in areas from the breeding grounds to the wintering grounds are indicated in table 19. Sex ratios taken in southern Manitoba for the pintail, shov- eler, and canvasback suggest that large numbers of drakes make an early depart- Table 19.—Drake percentages in 12 species of ducks é Ittinois NATURAL History SuRVEY BULLETIN Vol. 27, Art. 6 ure from the heavily gunned marshes of Delta and Netley. This early movement may be initially either south or north, the direction depending somewhat upon the species. Information on the early flights of drake pintails, some of which arrive at the Gulf of Mexico in August, indicates that the initial movement of these birds — is south. Records of large numbers of — drake canvasbacks and redheads in north- — ern Manitoba and Saskatchewan marshes suggest that these birds probably move north from their breeding grounds before they move south. In most species of ducks for which data are available, drakes made up a smaller proportion of the hunters’ kill in Mani-— toba than in three states to the south, North Dakota, Illinois, and Tennessee, Seis table 19. These data indicate that in most — species more drakes than hens left Mani- toba in advance of the hunting season there. A trend toward an_ increasing drake predominance from north to south was evident as far south as Tennessee. In all but two species for which data are available, the gadwall and shoveler, the predominance of drakes was greater in Tennessee than in IIlinois. a significantly greater number of hens than of drakes was evident in two species, the mallard and the pintail, and approxi-— mately balanced sex ratios were evident in four species. In all six species it was ap- parent that more drakes than hens were In Louisiana, ManirTosa, Nortu Dakota, ILLtNo!s, 1946-1949 1949 1939-1950 SPECIES Number | Per Cent |} Number | Per Cent | Number |} Per Cent of Ducks| Drakes | of Ducks} Drakes | of Ducks} Drakes Mallardcce. apes irccets srced erento 8,259 52.4 2) 212 57.5 | 22,008 56.5 BLACK UC sede esc ates Gea ae se eee leet esa: cube eisel or niktaete siralcco) ne et eae Gad wall: murs veers ce ae rete ee 476 55ae 579 54.1 Bald patever. 4 dems sna aur cians 969 522 146 53.4 PANEL swat fiers, Sars CE eto 1,438 49.0 210 53.0 Green-winged tealifcy .2 ck. «.ssegiaete en: 315 Sed 86 5355 Showeletiy so act Wek ae ee Dee 423 47.3 137 51.0 jaa aro Pe GM PN eae Nt Re EIS i, 5 RS, le UR i A bares Aaa 9 342 5550: |... 2.0005) ee Ringenecked) huckccy....tcsisicss aysesets crite + cxcyers oval cveae scion tee t atl poral t eae ieterel| eee meas ane RAVES RGR a civ gee ses ous tise tt aoe 2,348 40.7 281 56.0 j EDITS CCE [oe eg ae RA arn a Ea 860 51.6 136 522 PRY Ghee has a as Go Soils a to op 0 ote widvowws winyns ve bes acy u's Ud oy bs koera, Giolla Kio we Gliese cs alae eanetitan *Sources of data for the various regions: Louisiana, Richard Yancey, Louisiana Wild Life and Fisheries Commission (per- North Carolina Wildlife Resources Commission (personal communication). mission (personal communication) ; Barber, Jr., Manitoba, Delta Waterfowl Research Station; North Dakota, Hielle August, 1961 north of Louisiana during a large part of the hunting season. For all species of ducks except the shoveler, the differences in sex ratios among the various regions were statisti- cally significant. This conclusion must be taken with some reservations because the span of years involved was not the same for each of the various areas. Some of the observed differences could be due to time as well as geographic differences. Among adult mallards bagged in IIli- nois, 1939-1955, there was a steady in- crease in the drake segment of the fall population through the third week in No- vember, fig. 3. The ratio between the sexes then tended to stabilize for a period, followed by an increase in the drake seg- ment in the wintering population, usu- ally present in Illinois after the first week in December. In Utah, sex ratios of adult mallards bagged were relatively stable throughout the autumns of several years in which bag checks were recorded, fig. 4. Adult pintails bagged in Illinois and those bagged in Utah showed little varia- tion in sex ratios during the fall. Adult green-winged teals and shovelers bagged in Utah showed an increase in the drake segment as the season progressed, fig. 4. In only a few species do there appear to be differences in seasonal movement be- tween drakes and hens of the juvenile class. In Manitoba, the canvasback had an unusually large number of hens among BELLROSE ef al.: SEX RATIOS AND AGE RATIOS 409 the juveniles bagged, table 12; in Illinois, on the other hand, this species had an unusually large number of drakes among the juveniles bagged, table 14. The drake segment of the juvenile mallard popula- tion bagged in Illinois increased through the second week of November and then tended to stabilize, fig. 3. Sex ratios of ducks in the marshes ad- jacent to Great Salt Lake, Utah, have been quite variable from week to week and year to year in autumn. The week-to-week variation in sex ra- tios among ducks of these marshes is un- derstandable in view of the fact that in early summer the areas are the breeding grounds for ducks of many species, later a major molting area for transient pin- tails and green-winged teals, and still later one of the important migration areas for ducks in the Pacific Flyway. Chrono- logical differences in movement of vari- ous groups of ducks—those that breed in the area, early migrants that wing-molt in the area, and large numbers of fall migrants that rest there—have resulted in ever-changing sex ratios. Year-to-year variation in sex ratios is shown in data from the Bear River Mi- gratory Bird Refuge at the north end of Great Salt Lake (Van Den Akker & Wil- son 1951:379). In that area hens out- numbered drakes in 8 of 13 species in the period 1936-1940. However, during the hunting seasons in later years, 1943-1949, checked in hunters’ bags in seven regions in North America.* TENNESSEE, LoulIsIANna, Texas Coast, NortH Carona, | ProBasiLity 1951-1952 1951 1947-1951 1948-1952 THAT DIFFERENCES AMONG AREAS Number | Per Cent | Number | Per Cent | Number | Per Cent | Number | Per Cent Are DUE of Ducks! Drakes | of Ducks| Drakes | of Ducks| Drakes | of Ducks} Drakes to CHANCE 14,068 58.1 3,471 45.5 2,683 44.1 73 50.7 <0.0005 127 SLOSS yl ienesteee ae et | [Eerste ne ea aoe SN a AR RI 109 ie Seal HI tee ee ee en 2,007 HITS Sa ipaley cag ON [Aiea amen 696 43.7 228 57.9 <0.0005 317 GA Sil aeeu et tie tReet 620 Red 644 54.2 <0.02>0.01 1,084 67.1 1,204 45.9 2,688 69.5 271 70.5 <0.0005 688 63.4 eat 49.1 1,160 54.7 96 S120 <0.0005 174 SIG tan Be enal eres ll sie deus tectee 963 48.8 201 SN7, <0.20>0.10 107 (GSA cee ct ills ernie 1,782 rE re | Meee ot (EE aes Cede <0.0005 3,080 69.2 Soil CLS? ase | a uns ae na aia 104 61.5 <0.0005 544 69.1 78 51.4 227 48.0 349 41.8 <0.0005 516 66.1 752 49.5 456 62.9 48 40.0 <0.0005 282 Gor Sime nee eee lp ene Es Reva ie tener e 392 SOG et |e oes dec (1950:14); Illinois, authors of present paper; Tennessee, Charles K. Rawls, Jr., Tennessee Game and Fish Com- sonal communication); Texas Coast, Singleton (1953:57); North Carolina, T. Stuart Critcher and Yates M. 410 at Ogden Bay, midway on the east side of Great Salt Lake, hens outnumbered drakes in only a few instances: in pin- tails 2 years and in redheads 1 year, table 20. When the statistical significance of the differences between the data for these years was investigated, the year-to-year fluctuations in sex ratios were found to be 100 75 PER GENT PER CENT 0 I5-22 23-31 OCTOBER |-7 8-15 Intinois NaturAL History Survey BULLETIN Juvenile Hens al ‘Adult Hens NOVEMBER highly significant for all species except the baldpate and the shoveler. Popula- tions that were top-heavy with drakes were observed in this same area before the hunting seasons of 1944 and 1950. Ducks that were victims of botulism in the Og- den Bay area showed that adult drakes were much abundant than adult more Ys \-7 8-15 DECEMBER 16-23 24-30 Vol. 27, Art. 6 Fig. 3.—Drake-hen composition of the adult and juvenile segments of the autumn flight of mallards in Illinois, as indicated by data from checks of hunters’ bags, in the autumns of 1939 1955. The drake segment of the juvenile mallard population increased through the second 2 week in November and then became relatively stable. 411 Sex Ratios AND AGE RaTIOos BELLROSE ef al.: August, 1961 hens in late summer and early fall of these years, tables 21 and 22. At the Bear River Migratory Bird Refuge during the sum- were abnormally abundant among botu- mer of 1952, drakes of several species lism victims, table 23. $000°0> S0°O $000°0> $000°0> S0°0 S000°0< 100°0> $00°0<10°0> HONVHD O1 4NnG aay Suva SNOWY SAONTAAAAIC] LVHI ALITIGVEOU # 6FOI-EF6T ‘YeIN ‘esnyoy psrgq Avg uopsO 3e s#eq ssojUNY ur ane) Ww s2ee s (! ow @ by aS § A, w T = or =) MH HEE — W a _hs | 2 3 ad: o ~ Dore res ant a sige — 5 Be: cea =) n . (e} 6 ft Oe av (ale mM ages Ns 2 wd: | BOS ee a =O: of on it ta np: —w aw, go gale HS: @O § .cs.o7 =e = = = o.4 N=) Ss 3 WwW OT swt i ait w beth GN e iZ ©» O #2227 .-E= Fs Bi iT 2 <= hes Sv oe # Oc at See } e # es eS SY .= g ox zi 25 93 me oi +e S xo iO. arene vo wo oe) pW ecars i e ga (oar iWa5. Yad IN39 3d LN39 Y3d Bato juowjiedaq awed pure ysty yeip ‘uospPN *y puejON Aq parddns 6F6]-¢P6] JO} BIep peystqnduy, 8° PS 6FF € 6h LIC 0°89 CCl 0°09 O¢ b°98 bP 9°09 ef pL becnbedd 8°6S 6ve T | F755 CDi = .9°86 600% | 9°85 708. 09 eth 9°S TAD renee 7°09 P88°l | 6°€9 CPS T1679 PLE C8 || Sek SIS Gan Se 19 ELT 1°09 187 kat pasuIM-useIH ORGS Papo. aL iSp SPT c. || 9" 1G CLES) Oo Sp SBLAG A Abe eee tee L°8S GEG) lie ties [wattd OFS FC8 Ls 9e1 ‘I Shy 108 SAS L81 Gauss 9CF IES OST abel sl het | BE9 O89 || 36755 £59 6°85 Gre Ty) 6.19 OF 8° $5 IF7 8° es SLE ie Deeps 8°95 875 “1 8° PS 9L7 I 8°8S 6£7‘T £65 88 ¥S9 8Ie s*19 807 PALTRY soyxeiq syonqd soyeiqd syonq Saye4qd syonqd soyeaqd syonqd soyvid syonqd soyviqd syonqd qus7) jo qua) jo quay jo quay jo quay jo quay) jo - iq Joquinyy Ig Jaqunyy Ig Joaquin yy 1g Jaquinyy Rg Joquinyy Ig Joaquin \y SaloedS 6761 8P61 Lr6l 9F61 Fr6l Chol pex9949 syonp jo 412 early spring have revealed differences in the sequence of the northward migration of drakes and hens of the same species. The sequence in the migration of drakes and hens varies with the region, table 24. In the Illinois River valley, tallies of drakes and hens in late winter and spring were compiled for the years 1940-1946, fig. 5. A preponderance of drakes was most pronounced for the mallard, pintail, can- vasback, and ring-necked duck late in February. In the redhead and the lesser scaup, drakes predominated to the great- est extent in the second half of March; in the baldpate, in the second half of April. Farther north in the Mississippi Fly- way, in Minnesota, Erickson (1943:27) observed changes in the drake and hen seg- ments of the populations during the spring migration periods of 1938-1940. Among Table 21.—Drake percentages in seven species of ducks, juvenile and adult classes, afflicted : with botulism at Ogden Bay Bird Refuge, Utah, August 1 to September 29, 1944.* SPECIES Number ME ee ee oe ae 77 Ganwall eee rte a. ate ae 7 Haldia... Aoi ss eas ce ons 29 Pini tail Chto sess trawler Oe one 502 Greem-wintted: teals suse. Sg sie sine es 292 Crnnation teal oo.6.2c oes neta 17 Shaveleren eect anki eens eee 89 AUD SI CELE Sees tae bes oa teshee ice 1,013 *Unpublished data from Noland F. Nelson, Utah Fish and Game Department. Table 22.Drake percentages in six species of ducks, juvenile and adult classes, afflicted — with botulism at Ogden Bay Bird Refuge, Utah, late summer, 1950.* SPECIES Number Mallakd he Ae Let N Oc S Sicdn 4 Gadwalliesse ois tree nics cee ee 3 Pia dO 2 oo dincds'y, cia, ats mips wp Bin 63 Puritans 3 eee skins Gee ae 299 Green-winged teal iid. 2 6 eles. 2 a 13 lig eetleies oie rashes siuioee Wccate ators Bin ae 34 8 ee NER PPO A a Ca 416 *Unpublished data from Noland F. Nelson, Utah Fish and Game Department. I~urinois NaturAL History SurvEY BULLETIN ADULTS JuvENILES Per Cent Per Cent Drakes Number Drakes 71.43 43 48.84 14.29 10 40.00 86.21 9 44.44 60.56 163 45.40 80.14 118 62.71 58.82 Sp) 65.63 69.66 71 71.83 68 .21 446 55.83 ADULTS JUVENILES Per Cent Number Per Cent Drakes Drakes 50.00 12 83.33 66.66 rs 14.29 52.38 71 45.07 70.57 91 62.89 38.46 a 33.38 50.00 25 48.00 64.90 215 53.85 Vol. 27, Art. 6 blue-winged teals, in 2 of the 3 years, the relative number of drakes was consider- ably greater in the first than in the second ~ of the two parts into which Erickson di- vided the migration period. Among shoy- | elers, in each of the 3 years, the relative number of drakes was greater in the sec- ond part than in the first part of the mi- — gration period. Among lesser scaups, drakes predominated throughout the mi- — gration period in each year, but to a lesser _ extent in the second part than in the first. — Among ring-necked ducks, the sex ratios — varied little between the two parts of each — migration period or among the 3 years; — the average male to female ratio for the — 3 years was 1.36:1 in the first part and — 1.43:1 in the second part of the migra- — tion period. 4 Near Minneapolis, in the spring of — 1950, Nelson (1950:119) observed male to female ratios of approximately 1.3:1 — August, Table 23.—Drake percentages in four species of ducks, juvenile and adult classes, afflicted with botulism at the Bear River Migratory Bird Refuge, Utah, summer, 1952.* SHOVELER MALLARD GREEN-WINGED TEAL PINTAIL Adult Juvenile Juvenile BELLROSE et al.: SEX RaTIos AND AGE RATIOS norm CO coomwonm else) m™~wowoo my NoOwnro mn SNM mM =e IMAHH ow Nocro So m~ovwr my NON — Noli se) Aw SY =O “moO On Ci a) Om “MOr~ ™~™o mw tH wow met (ej Ss July 4th week... Dn + U 5 5 S-4 aS anne. “NC coo + = Ao “mh Ww : | eal | > 5 3 ' . mea} § w +079 00 Nol ws Oo “wom oon 5a - nN ere g = ~ . \O S54 epee oat v 18) “COO MO eS Z x ' 3 Ex “904 wt 53 0 “~E HD Aa . roo) A n a2 \o mewon tH ZIeOk SSSR HS re vu > ej U psu AMD Neflea me) Ex co toro ac 53 ¥ ANNA aloe) 7 z — Ist week .. 2nd week... September Type C, on the Bear River Migratory Bird Refuge During Sum- Afflicted by Clostridium botulinum, “Sex and Age Ratio of Waterfowl 1952” by Jack P. Allen, Utah Cooperative Wildlife Research Unit, Logan. *Calculated from data in a report, mer, 413 among river ducks and approximately 2.0:1 among diving ducks. In northwestern Iowa, Glover (1951: +86-91) recorded sex ratios for migrat- ing waterfowl during spring in 1948 and 1949. The preponderance of drakes he observed among early arrivals of mallards and blue-winged teals declined somewhat, and thereafter the sex ratios of these spe- cies remained fairly constant. The sex ratios of gadwalls varied little during the spring. Drakes predominated in baldpate populations throughout the northward mi- gration period, to the greatest extent to- ward the end of the period. The drake seg- ment was greater than the hen segment among pintails and shovelers throughout the spring migration and showed peaks in late March, the middle of April, and early May. The drake segment among lesser scaups also exceeded the hen segment throughout the spring migration; a marked peak in drake abundance was reached during mid-April. Drakes pre- dominated markedly among the first red- head arrivals, and again among the late departures. Among ring-necked ducks, a high peak in drake predominance occurred the first half of April; a near balance in sex ratios prevailed during the remainder of the spring migration season. In the lower Souris National Wildlife Refuge, North Dakota, Merrill C. Ham- mond found marked variations in water- fowl sex ratios taken at different times during the spring, table 7. Pintail, lesser scaup, and redhead sex ratios were more heavily unbalanced in favor of drakes late in the spring than early. Changes in the sex ratios of pintails were significant at the 95 per cent level (X?=20.9, 3 d.f.). The changes were not significant at the 95 per cent level for the lesser scaup (X?=3.1, 2 d.f.) or the redhead (X?= (dee). In the Pacific Flyway, in western Washington, Beer (1945:119) calculated sex ratios of ducks from September through April. In December, mallard sex ratios were evenly balanced; in January, they were slightly in favor of drakes and, in February and March, slightly in favor of hens. The drake segment in the pintail population progressively declined from November through March. The sex ratio for lesser scaups was balanced in January, 414 ILtrnors NaturAL History SuRvEY BULLETIN Vol. 27, Art. 6 Table 24.—Drake percentages in 10 species of ducks observed NortH Catt- Wasu- ; OREGON, Dakota, Manirosa, 1948-1921 | 1946-1948 | 1943 1944 | 1939-1942, | 1939-1945 3 1947-1950 SPECIES bh n Vv = 3] 83 EWP ox 53 6A}500 Z. Ay Malate sae ibe eee ean 1,039] 55.4 | 5,589) 55.9 | 1,652) 50.7 | 3,202) 51.7 | 2,423) 50.6m Balin ate. oo isc ce aks 432] 45.8 30| 53.3 | 4,999} 53.3 911) 57.20) 540 el Petal vc aes et eaaiceas cals ace ly ane 4,561} 57.4 622} 52.2 |10,173) 52.7 | 3,250) 51.99 Loy These Lciegolt in eco: | ape REA POM Udi, (PPS Bagi ie IN (ap bo 5,554) 55.5) les. nae eli ri de sae an eS ele ok Rep ee 362) 6926") 2,823) 5974 101) 53.5. | 2,000] SS) 7g nee 3 Reed ear 28d Oa. aciard ts pihacanaaece aa ane Uiheaea terre ae et ke cua mi Rote 1,805} 54.8 | 926 | 58.1% Ring-necked duck.......... (eNTAING Pao) OSS] Pap ess Dae alin aN Paar eal lbrcre he 63) (57.12 ee = Ganvasback Sie erie SHAG) WeeeGhes Oot lie euansia jamie oak 316} 67.7 826] 62.6 | 2,916) 65.4 ~ [sessen/scavipive 2 faa fos sats BS AL st Sirf | Pes PAA De 911} 59.8 | 7,401) 64.0 |10,387| 66.8 Bechet Che. dicar Soy ee Ny ie be eR eR eee «cock Rah sites rete 1,886) 64.7 |... ..)eeeaee % *Sources of data for the various regions: California and Oregon, Evenden (1952:393); Washington, Beer _ (1946:409); Minnesota, Erickson (1943:27); Illinois River Valley, authors of present paper (unpublished); Mis-— (1951:487, 490) for mallard, baldpate, pintail, blue-winged teal, and shoveler, and Glover (1951:489) and Low — ford (1954:78). Lesser Scaup 90 x \ 2 \ Ring— Necked Duck = ae aS aX ee a a \ 80 \ \ uw =x .- 4 e é - — #20 WwW oO 4 Ww a 60 eee a Baldpate 50 2! 8 16 24 8 16 23 FEBRUARY MARCH APRIL Fig. 5.—Periodic changes in the drake percentage of the flight of each of seven species of ducks during spring migration in the Illinois River valley, 1940-1946. Data were obtained from counts of living birds. A preponderance of drakes was most pronounced for the mallard, pin tail, canvasback, and ring-necked duck early in the migration period. For the lesser scaup, é preponderance of drakes was most pronounced in the second half of March. : August, 1961 BELLROSE et al.: SEX Ratios AND AGE Ratios 415 mostly during the spring months in 10 regions of North America.* Mississippi ee ee “| alg trom) ames | paoniewes 1938-1940 VaLLey, Iu.wors, 1949 1949-1952 AREAS THAT 1940-1947 | 1948-1951 DIFFERENCES AMONG hi n O| u n G| yu n Gl re PA ae an rs a ARE 2 S| gals S| gels S| eslS | ee] &) ge] Per Cent me 3 oS. 2 3) ein = 3) fea, = Oss |ieieee oO & Deak CHANCE 53 0AI5OA]5 oA) 500A] Ss SAl5OA|s SA)/sO0A|s sAly00 AGUAS Zz A, Zz Ay Z AY Z Ay Zz Wf 256} 50.4 |11,125| 54.8 800) 53.2 |17,085) 52.7 |10,431} 50.3 52.6 <0.001 126) 54.8 | 1,238) 61.6 fis) S8iokh |) WSs} 5G) || WE 752) 5525 54.6 <0.001 322) 53.7 | 4,218) 63.2 | 2,000} 77.4 | 4,370} 71.8 | 5,178) 54.6 59.4 <0.001 447| 59.7 POTN GSA al Ee cee | Perri 3,782) 59.6 | 1,644) 56.8 59.3 <0.001 253) 56.5 Poe skeen 1 eee ae Creceiok 2,377] 66.6 892) 63.5 60.1 <0.001 PO MOON 75880] 60.1 I... cn alls nee «< 45385| 580) | a2 75| OO, 60.2 <0.001 OOM Nee OSL. 1304 cae 2 alle sctee GoM (7/0) |) O59) 4252 61.4 <0.001 147| 64.0 | 6,164) 79.4 | 3,678) 75.2 | 2,049) 65.0 | 2,016) 65.3 66.4 <0.001 3,114) 72.0 |19,188) 86.9 17,873} 82.1 |11,434) 69.1 |11,885| 57.0 69.5 <0.001 80] 48.8 AGO eA le ste sual ates 19976) 65..8 438) 53.4 62.0 <0.001 (1945:119); North Dakota, M. C. Hammond, U. S. Fish and Wildlife Service (unpublished); Manitoba, Hochbaum sissippi River Valley, Illinois, George Arthur, but by April there were almost two drakes to every hen. In eastern Washington, Yo- com (1949:226) found among mallards relatively more drakes during December than during other months of his study; the number of hens increased proportion- ally in January, and in February there were more hens than drakes. In the first + months of 1948, sex ra- tios of mallards in the Texas Panhandle were obtained from counts of ducks pre- sumed to be victims of fowl cholera, table 25. These data revealed statistically sig- nificant (X?=16.5, 6 d.f.) chronological differences in sex ratios at the 95 per cent level. In winter the mallard drakes and Illinois Department of Conservation (unpublished) ; (1941:144) combined for redhead, ring-necked duck, canvasback, lesser scaup, and ruddy duck; Glover Mum- Iowa, Indiana, hens were about equal in number. The drake segment increased during the spring migration, and it was especially large at the end of the migration period. Inas- much as hens were found by Singleton (1953:57) to predominate in mallard populations on the Texas coast during the hunting season, table 19, it is assumed that the progressive increase in the drake segment in the Panhandle resulted from the lingering of unmated drakes on the wintering grounds. Large numbers of mallards are paired during the fall and winter; probably some of the unmated drakes were juveniles that had lagged in testicular development while others were Table 25.—Drake percentages in mallards and pintails found dead, presumably from fowl cholera, on the Muleshoe National Wildlife Refuge, Texas, 1948. MALLARDS PINTAILS PERIOD Per Cent Per Cent Number Wakes Number Drakes Memes Heb: (6)... dec dacksGeewe sas | 21 50.2 330 64.8 eran) Oe cet ce eee oe ds Senate 436 54.6 98 60.2 —veloy, DIES Ege i ty aa eee 3,014 56.0 769 5720 ay ela Tg ae ae ae eet 831 5/58) 236 54.2 MMe ee ceeme oot al sisiers, fa cGue oa 643 56.3 328 55.8 2 Sl TESA Sneed er 162 56.8 16 43.0 Gall RSG Get ae teen ee eee einer 47 63.8 8 50.0 TRA A DTU OD > sscaiccte so sie eis coe’ 6,345 55.0 1,785 57.9 416 adults in which the testes had not reached recrudescence. Among pintails presumed to have died from fowl cholera in Texas in the first 4 months of 1948, the sex ratio trend was the opposite of the trend among mallards, table 25, from a population predominantly Ittrnors NArurRAL History SuRVEY BULLETIN Vol. 27, Art. 6 in Mexico, than does the mallard popu- lation. Sex Ratios in the Breeding Season. — —Seasonal changes in sex ratios of ducks — observed on the Manitoba breeding — grounds in 1947 and 1949 are shown for various species in tables 26 and 27. In drakes at the start of the period toward a_ April, the first flights arriving on the . balanced population at the end. The breeding grounds showed, with minor ex- — change in pintail sex ratios was not signif- ceptions, a closer approach to a balance — icant at the 95 per cent level (X°=10.4, between the sexes than did subsequent : 6 d.f.). Drakes were found to predom- populations on the breeding grounds, fig. — inate in the pintail population along the Texas coast during the hunting season, table 19. It may be concluded that the pintail drakes tend to winter farther north than the hens but that most of the pintail population winters farther to the south, ee 6. Somewhere between the mid-flyway areas and the breeding areas of southern — Manitoba, late migration waves predom- : inating in hens appeared to overtake early — migration waves predominating in drakes. 3 A tendency toward balanced sex ratios Table 26.—Drake percentages in seven species of ducks observed in four periods of the spring months along study transects on the Manitoba breeding grounds, 1947.* Apri 15-30 May 1-15 May 16-31 June 1-15 SPECIES Number Per Number Per Number Per Number Per of Cent of Cent of Cent of Cent Ducks Drakes Ducks Drakes Ducks Drakes Ducks Drakes Mallard....... 162 52.5 341 67.5 150 77.5 308 78.0 a rahy gl iene ge eames. al HSER Pha ie 72 54.0 45 55.5 89 56.0 Pinta: 2 62 140 55.5 248 75.0 139 73.5 197 78.0 Blue-winged fealuie suet. 41 62.0 297 58.0 153 59.0 283 71.0 Shovelete te csc lec st calteeeeaet 240 55.5 60 58.0 135 69.5 Canvasback.... 164 55.0 139 65.5 125 FES) 139 83.5 Lesser scaup.... 48 67.0 616 66.5 118 61.0 211 65.5 *Data supplied by Arthur S. Hawkins, an author of this paper. Table 27.—Drake percentages in 10 species of ducks observed in four periods in the Mina nedosa pothole district of Manitoba, 1949.* ; ApriL 21-25 ApriL 29-May 7 May 14-JuNnE 6 Jury 5-26 SPECIES Number Per Number Per Number Per Number Per of Cent of Cent of Cent of Cent Ducks Drakes Ducks Drakes Ducks Drakes Ducks Drakes Mallard....... 829 53.9 fee. 67.9 975 73.6 194 Gadwalliae en stle os ceeelnd eee 75 54.7 220 57 33 Baldpate........ 73 521 209 53.6 363 54.8 61 Pinta: Gases 213 59.2 235 74.0 274 76.6 67 Green-winged tealsjsetesetcn 52 53.8 198 53.5 164 63.4 40 Blue-winged teal ass tic NG ei Suissa 547 53.9 925 57.4 350 Shoveler....... 32 50.0 124 58.1 201 Se, 51 Redhead....... 64 51.6 114 52.6 231 55.4 34 Canvasback.... 190 54.2 285 56.8 334 61.1 135 Lesser scaup ... 163 65.0 442 60.2 459 58.8 166 *Unpublished data supplied by W. H. Kiel, University of Wisconsin. August, 1961 among early arrivals on the breeding grounds evidently is observed in late March and early April on the Oka State Sanctuary in Russia, where the first mal- lards to arrive are paired (Teplov & Kar- tashev 1958:160). The upward swing in the relative num- bers of drakes among the mallards and pintails seen by observers in early May, tables 26 and 27, soon after arrival of the ducks on the breeding areas of Manitoba, may be indicative of the rate at which hens leave their mates to incubate. By mid-July the relative number of 80 70 60 — —— SO Baldpate 40 PER CENT DRAKES 30 20 APRIL 21-25 BELLROSE et al.: SEx RatTIos AND AGE RaTIos APRIL 29-—MAY 7 417 drakes among ducks seen on potholes in southwestern Manitoba, table 27 and fig. 6, had noticeably decreased in all species —less in the lesser scaup and the blue- winged teal than in the other species. At this time, the drakes were evidently leav- ing the breeding areas for the lakes or marshes where they would enter the eclipse molt. A similar sequence in sex ratios was found in 1949 by I. G. Bue, then at the University of Minnesota, in ducks seen on stock ponds in western South Dakota, fig. 7. Between the first week of May JULY 5-26 MAY |4 —JUNE 6 Fig. 6.—Periodic changes in the drake percentage in each of six species of ducks on a breeding grounds area near Minnedosa, Manitoba, April 21—July 26, 1949. Data were obtained from counts of living birds. 418 and the last, during the time pintail hens were leaving their mates to nest, the num- ber of drakes increased from 57 to 81 per cent of the pintails observed. An abrupt decrease in the relative number of pintail drakes took place in the first half of June when many of them were departing for areas in which to molt. Mallard drakes were about 2 weeks later than pintails in their departure to molt, and blue-winged teal drakes were about 2 weeks later than the mallard drakes. Sex ratios of ducks seen during the nest- 80 75 70 65 PER CENT DRAKES 60 55 50 8 IS 2i | 9 Fig. 7.—Periodic changes in the drake percentage in each of three species of ducks on stock ponds in western South Dakota, April 8—July 17, 1949. Data were obtained from counts of living birds and were provided by I. G. Bue, Commissioner, North Dakota Game and Fish Depart ment, Bismarck, while at the University of Minnesota. ILtinois NArurRAL History Survey BULLETIN 6.) 22 29.75 12 MAY Vol. 27, Art. 6 ing period may provide useful informa-— tion on the destruction of duck nests. When their nests are destroyed, hens re-— turn to their waiting sites, where they can be seen by observers; this behavior results in an apparent increase in the rela- tive number of hens in the populations. — Lynch (1948:26) presented evidence to show increases in the relative numbers of — paired mallards and pintails seen on a study area in southern Saskatchewan late © in May, 1947. These increases may have been attributable to heavy nest losses re-— = August, 1961 sulting from the plowing of wheat stubble in which hens were nesting. Regional Variations in Sex Ratios Sex ratios in ducks were found to vary with migration routes and wintering grounds, fig. 8. The relative number of drakes among mallards reported bagged in the late 80 70 60 50 ram o, © “ fe o, oO os 2 2, 2 ss x °, © XX 2, <4 x O.8 S00 S o.8 © ©, OY S252 o, & o, 2525 Se SKS 5505 KS re rates SX ee o, 0.10 Baldpate........ 1,940 991 Sie 168 shay || ube sp Weil) SS0),28) GAN cs ce ees MATS | 132697 4) 3980 582 263 | 45.2 + 6.2 |<0.01>0.005 Green-winged Realltsralcns sas leys.« 15973 1,031 By 58) 70 35) | 5020 = 23) |< Oe 0 0560 Blue-winged teal | 12,343 | 6,171 50.0 341 168 | 49.3 — 057 | <05805-08 75 Shoveler........ 686 346 50.4 41 29 TOE 7 + 20.3 |<0.01>0.005 Redhead........ 2,042 | 1,100} 53.9 266 148 | 55.6 aie ld 060-0750 @anvasback..... 511 245 | 47.9 60 a AS 0 — 2.9) |'<0-60>0:.50 Messer scaup...-| 5,134) 2,615 | 50.9 320 159 | 49.7 — 1.2 |<0.70>0.60 *Data calculated from Cartwright & Law (1952:10-2). balanced sex ratios in ducks, it is desira- ble to examine the influence of each of the several factors responsible for mortality in these birds. The principal agents that contribute to mortality in ducks are (1) hunters, (2) disease, (3) predators, (4) agricultural operations, and (5) natural stress. We seek to answer this question: Are hunters, disease, predators, agricultural operations, and natural stress responsible for greater loss in the ducks of one sex than in those of the other? Hunting and Sex Ratios.—The data on hunter kill of ducks banded in Can- ada, 1939-1950, and recovered in the year of banding, table 28, reflect the coun- try-wide influence of hunting on the drake-hen ratios because the banding was done on the breeding grounds during late summer and early fall at or before the be- ginning of the hunting season and the southward migration period. Statistical treatment of the data showed that hunters took a highly significant greater number of drakes than of hens in the mallard, gadwall, pintail, and shov- eler. Hunters took fewer, but not sig- nificantly fewer, drakes than hens in the green-winged teal, blue-winged teal, can- vasback, and lesser scaup. Data for black ducks banded at Lake Chautauqua and at McGinnis Slough and for mallards banded at McGinnis Slough, tables 2, 3, and 4, showed no significantly greater hunter kill in one sex than in the other for the period of study. Data for mallards banded at Lake Chautauqua, ta- ble 1, showed a greater hunter kill in drakes than in hens; the difference in hunter kill between the sexes was statis- tically significant and similar to that for mallards banded in Canada, table 28. In most species in which hunting takes a greater toll of one sex than of the other, the male segment bears the greater loss. However, the effect of hunting on the sex ratios of the entire North American duck population is probably insignificant. Disease and Sex Ratios.—Although numerous diseases afHict ducks, only three are known to cause large losses among these birds: (1) botulism, (2) fowl chol- era, and (3) lead poisoning. Botulism.—Botulism in ducks occurs in both Canada and the United States; it is most prevalent among the populations in the Prairie Provinces, the Northern Plains States, and the Western States. The time of botulism outbreaks usually is from midsummer to early autumn. According to Hammond (1950:213), There appears to be no selectivity of sexes as far as Clostridium toxin is concerned and the ratio of sexes appearing in the studies is a reflection of the differential utilization. If males were attracted to areas at a time when toxin was potent and available a preponder- ance of males appeared in the collection. + bo bo Entire Periop Aucust 29- SEPTEMBER 4 Aucust 7-14 Aucust 15-21 Aucust 22-28 Jury 28- Aucust 6 | | Jury 21-27 Table 29.—Drake percentages in seven species of ducks found dead or incapacitated, presumably from botulism, at Whitewater Lake, Manitoba, Jury 14-20 in 7 weeks of 1949.* Ittinoris NaturAL History Survey BULLETIN Vol. 27, Art. 6 % feat eyre! hae Hammond (1950:212) found a ratio of — & és Sard a te 161 drakes to 100 hens among 8,395 adult — a ducks affected by botulism on four national — ee a wildlife refuges in North Dakota, 1937-—_ ee = so 1947. The relative number of hens in- | = creased progressively from July through September. | An inspection of ducks that presumably — were victims of botulism at Whitewater Lake, Manitoba, between mid-July and — early September, 1949, revealed a prepon- — derance of drakes, table 29. There was an increase in the proportional number of hens among the victims in some species in~ late August; however, the hens in most large lakes with extensive marshes ap- pears to expose drakes more than hens to botulism toxin. The worst known botu- lism areas, such as Whitewater Lake in Manitoba, Johnstone Lake in Saskatche- wan, Medicine Lake in Montana, and the marshes about Great Salt Lake, Utah, are places where drakes, in much greater numbers than hens, annually gather for the wing-molt. Fowl Cholera—In North America, t © : species did not suffer severe losses, possi- bu tlee i aces g bly because the disease abated in early ate = ia < 5 September, before large numbers of hens — : » arrived. ruSloo iw a mvs Waterfowl afflicted with botulism at Agelos is g sicle the Ogden Bay Bird Refuge, Utah, in = : z 1944 and 1950 and at the Bear River Mi- ee = gratory Bird Refuge, Utah, in 19527 55: g|/SG :% A %=| 2 showed a preponderance of drakes among ZA” a : 4 both adults and juveniles, tables 21, 22, “ie 5 and 23. A comparison of the sex ratios 2a ee eee tees ~ of ducks dying from botulism in late sum- OG [Seon oe RF mer of 1944, table 21, with those killed = by hunters during autumn of the same 4 ee bag re Ess #4Ee S Vol; year, table aC indicated ue pak He yas =) ta eal ba “| 5 proportionally greater numbers of drakes = among the birds dying of the disease. The = : g the g The Zee lncot a ne * fact that, in Utah, drakes were relatively BOs Sxse & RS! Ee more abundant late in the summer than g during the autumn may have accounted, Enuticenm 92 om = at least in part, for relatively higher num- ee - ars Be ear Sete lee 2 bers of drakes among disease victims than = among shot birds. a . weglannn © on 5 The habit of drake dabblers, while un- ASE sags ¢ gels dergoing the eclipse molt, of frequenting c é A 2 o tS} E 4 6 roa a 2 S| z 3 ° = is] vo a E mel Tjareya Poa eae largest losses of migratory waterfowl ‘roti is = irs sees Erreee fowl cholera appear to be those reported o — Gre «Sos ‘i a ed G5 eo ee for the Panhandle of Texas by Petrides & & ZSfecaiue 3 Bee eessys Bryant (1951:193). Other severe losses ZOMHO M H from this disease have been reported from August, 1961 the south end of San Francisco Bay northward through the delta and into the lower Sacramento Valley (Rosen & Bischoff 1950:147-8). Although Petrides & Bryant (1951: 203) found some indication that the smaller the duck the more susceptible it is to fowl cholera, the weight difference between drakes and hens in any one spe- cies is not great enough to account for a material difference in mortality rates. A small number of drake-hen ratios for mal- lards and pintails, living birds and victims of fowl cholera, in the Texas Panhandle in 1944-1946, table 30, suggest that the disease is not markedly selective of either Sex. Sex ratios for several hundred ducks presumably dying from fowl cholera in the Texas Panhandle in 1944-1946 and 1948 are given in tables 30 and 31. The loss of pintail drakes was proportionally greater in 1948 than in 1944-1946. The loss of mallard drakes showed approxi- BELLROSE ef¢ al.: SEX RATIOS AND AGE Ratios 423 mately equal percentages in the two pe- riods. In each period, the loss was pro- portionally greater among pintail drakes than among mallard drakes. Available evidence suggests that fowl cholera is not an important cause of dif- ferences in mortality rates between the sexes. In the recorded outbreaks of this disease among ducks, drakes have predom- inated in the populations and have suf- fered losses proportionally no greater than those of hens. Lead Poisoning—Among_ migratory waterfowl, lead poisoning is more wide- spread geographically than either botulism or fowl cholera. It has been estimated (Bellrose 1959:282) that among all spe- cies of waterfowl in North America 2 to 3 per cent die from this disease each year. Following experiments with penned wild mallards, Jordan & Bellrose (1951: 21) concluded that: The hen mortality from lead poisoning was found to be double the drake mortality, except Table 30.—Drake percentages among pintails and mallards in the Panhandle of Texas, 1944-1946, as determined by (1) counts of ducks believed to be victims of fowl cholera and (2) visual observations of healthy ducks.* PINTAIL MALLarD Visual Visual PERIOD vations : vations ae a Per Cent | Per Cent rs Per Cent Per Cent Dhacks Drakes Drakes ites Drakes Drakes Miarch:4—16, 1944...5...... 311 + oll seteae eects 187 EY ieee Uhl incite aeoene ee Bebe 1819456 os ask ee 552 55 56 281 51 48 er chel O94! Fe cee Ss DEY) 64 65 64 70) tm ere ene tes Feb.—March, 1946.......... 1,008 63 71 346 E16, Wha ean ore oon *By Arthur S. Hawkins and U. S. Game Management Agents L. J. Merroka, Floyd A. Thompson, and M. H. Boone. Table 31.—Drake percentages in four species of ducks found dead, presumably from fowl cholera, on areas in the Panhandle of Texas, winter and early spring, 1944-1946 and 1948.* 1944-1946 1948 SPECIES Number Per Cent Number Per Cent of Ducks Drakes of Ducks Drakes ae PELE 878 Ce en ee er 54.4 SPC Cemee te ee eMne me tetas aredehrsiees fll eben decane cfetets a: [apr e navel SENG 860 62.6 LEI et a rar Oe ae a 2,093 62.1 7,447 Oil Beenie COBLe a lmeree mn ear llr nee erence leek soe als Meas, 192 SES *Data for 1944-1946 from table 30. Data for 1948 from U. S. Game Management Agent L. J. Dugger. 424 ILLINOIS NATURAL Table 32.—Drake percentages among mallards picked up dead or incapacitated from lead if History SurvEY BULLETIN Vol. 27, Art. 6 poisoning in several areas of the Mississippi Flyway during late fall and winter, 1939-1955. PLace Sand Lake- South: Dakotas: . ch siete ee Reine Heron: Lake; Minnesota: 5045.5 jas cee seit Vas Lake Chauteuaua, Hingis. < suk nies» es aes ws Daivhitowis Magn oi os oe ea ea ee is Oe an a ies Chaniten County, Missoan os eacc suse cae Claypool Reservoir, Arkansas..............6.+-- Catshanls Rake, Lois onaies. } oe ise sie et'es 4 NuMBER Per Cent YEAR CHECKED DRaAKES 1951 59 57.6 1939 194 63.4 1941-1955 753 62.8 1953 47 68.1 1949 53 64.2 1954 100 73.0 1953 243 44.4 in the spring season when hens entered the breeding phase. At this season the food in- take of penned wild hens increased steadily until it equaled, then exceeded, that of penned wild drakes. During this period hens proved to be less susceptible to lead poisoning than were drakes. At all other seasons hens ate less food than did drakes. In field experiments with mallards, some of which had been dosed with lead shot and some of which had not been dosed, Bellrose (1959:276) found that: Because of the smaller number of experi- ments conducted with hens than with drakes, it is more difficult to appraise mortality from lead poisoning in the hens. However, the available data suggest that, among hens and drakes with identical ingested shot levels, hens probably suffer twice as great a mortality as drakes in the fall and a small fraction of the mortality of drakes in late winter and spring. Actual counts of mallards picked up dead or incapacitated from lead poisoning in the Mississippi Flyway during late fall and early winter show a large pre- ponderance of drakes, table 32. Field observations on healthy ducks in the re- gion also show a preponderance of drakes in the wintering populations. Because most outbreaks of lead poisoning that have been reported are from the northern periphery of the wintering grounds and because drakes greatly predominate in wintering populations in those areas, un- doubtedly an appreciably greater number of drakes than of hens have died from this disease. Predators and Sex Ratios.—Inves- tigations of predation on waterfowl are not adequate to provide a substantial basis for appraising the role of predation in se- lective mortality for drakes or hens. The hens, while incubating eggs for 3 or 4 weeks, and later, in caring for the flight- less young for 6 to 10 weeks, may be ex- posed to greater predation than drakesil During the molt or flightless period, when — the tendency of hens is to remain on small _ bodies of water, while drakes congregate on large lakes or marshes, the hens may — be subjected to greater predation thal y Moreover, the poor physical con- ; drakes. dition resulting from the stress of egg laying and molting may also cause the hens to be more vulnerable to sredatioull Kalmbach (1937:383-4), in summa- rizing the fate of 512 duck nests on the prairie breeding grounds in Canada, re- es ported that eight egg-laying or incubating hens were known to have been killed by a Other hens may have been predators. killed by predators without leaving evi- dence; 40 nests had been deserted, and 53 b had been destroyed by unknown agents. Ina study that included 340 “active” duck nests in southeastern Saskatchewan — during 1953, Stoudt & Buller (1954: 58- 9) found seven nesting hens that had been killed by predators. near Minnedosa, Manitoba, Alex Dzubin of the Canadian Wildlife Service (letter, 4 March 26, 1955) found 13 hens and 6 — of ‘§ During three seasons on a 1.5 square mile study area “ a ~ s fi | on 2 e i drakes killed by predators, mowers, or muskrat traps. was atypical in being flanked by paved Because his study area highways along two boundaries, as well as by telephone and electric power wires, — ducks killed by colliding with cars or by flying into wires were not included in his figures. During a study of the fate of nests on farm land near Delta Marsh on the Por- — tage Plains of Manitoba, 608 nests of seven species of ducks were examined — although — many nests were believed to have been (Milonski 1958:223, 225); lost to predation (striped skunks de- August, 1961 stroyed 7 per cent of the pintail nests and 51 per cent of the mallard nests) only five hens were known to have been killed by predators. On Illinois study areas, raccoons de- stroyed 304 out of 1,579 wood duck nests and killed 103 hens in a period of 7 years. Minks killed other nesting wood duck hens, and even fox squirrels were respon- sible for the death of several hens. Census records indicate that during the nesting period wood duck drakes suffered negligi- ble losses. Agricultural Operations and Sex Ratios.—Losses resulting from mowing or combining operations on farm land are selective for nesting hens. Such _ losses would affect only species nesting in crops subject to mowing or combining. It seems probable that the mallard, pintail, gadwall, green-winged teal, blue-winged teal, bald- pate, and shoveler would be most exten- sively concerned. The potential loss of nesting hens is great, because extensive areas of farm land are included in the breeding grounds. As long ago as 1948, Lynch (1948:28) pointed out that the 75,000 square miles comprising southern Saskatchewan is far from being a vast undisturbed prairie and that “three-fourths of this ‘Duck-Factory’ are grain-fields. The remainder is heavily grazed.” According to Forrest Lee of the Min- nesota Department of Conservation (let- ter, January 9, 1955), the loss of blue- winged teal hens from mowing may be appreciable in Minnesota. One farmer near Hutchinson, despite the use of a flushing bar, in 1 year destroyed three hens while he was mowing an alfalfa field. A normally productive pond on his farm had no broods in that year. Interviews with a large number of farmers in the area indicated that such losses were not unusual. Of 122 mallard and blue-winged teal nesting hens for which there was a chance of being killed (on nests destroyed directly or indirectly) in the mowing of 592 acres of hay on Horicon National Wildlife Refuge, Mayville, Wisconsin, only 5 were killed (Labisky 1957:195-7). It was believed that this low vulnerability of nesting hens resulted because “dabbling ducks generally rise swiftly and nearly vertically from the nest when flushed by BELLROSE e/ al.: SEX RATIOS AND AGE RATIOS 425 the mowing machine, thus avoiding the cutting bar.” While making observations on 608 nests of seven species of ducks on farm land near the Delta Marsh in Manitoba, Mil- onski (1958:223) found only two hens killed in mowing operations. The available data indicate that losses of nesting hens resulting directly from agricultural operations do not contribute importantly to imbalance in adult sex ratios. Stress and Sex Ratios.—Little is known about stress, as defined by Selye (1956:3), in its relation to mortality in ducks. Kabat et al. (1956:44) found that in pheasants (Phasianus colchicus) the “seasonal variation in resistance to the applied stress and survival time was re- lated to the physiological condition of the hen at particular times of the year.” In July and August, pheasant hens that had completed or were about to complete their egg laying and were molting flight feath- ers were in their poorest physical condi- tion of the year. Survival of pheasant hens under applied stress was shortest in June, July, and August and longest in April, immediately prior to egg laying (Kabat et al. 1956:12). The average survival period in July was 13 days in one year and 18 days in another, compared to 21 days in October, 27 days in Decem- ber, 29 days in January, 34 days in Feb- ruary, 40 days in April, 22 days in May, 17 days in June, and 13 days in August. Without doubt the greatest energy drain experienced by duck hens in the en- tire year occurs during late spring and summer as a result of egg laying, in- cubation, brooding of young, and _ post- nuptial molt. This sequence of activity probably places the hens in much greater jeopardy to stress than the drakes, which experience marked depletion of energy only through the period of the post-nuptial molt. Harold C. Hanson of the Illinois Nat- ural History Survey has determined (manuscript in preparation) that among Canada geese (Branta canadensis) the stress of the molt is especially severe on the female following the energy demands of egg laying and caring for the young and that this produces a differential effect on the sexes which may be the primary cause 426 for the preponderance of males in adult populations. Evaluation of Mortality Factors.— Information available on the principal mortality factors affecting sex ratios in the North American duck population indi- cates that hunters and disease take rela- tively more drakes than hens and that predators may take relatively more hens than drakes. From the time of hatching to the be- ginning of the breeding season, only slight Ittinots NATURAL History SurvEY BULLETIN Vol. 27, Art. 6 the imbalance between the sexes in this population. Influencing the age composition, and therefore to a large extent the sex ratios of the population, are (1) productivity and (2) mortality. The more productive a species of water- fowl, the greater is apt to be the propor- tion of juveniles in its population at the opening of the hunting season. greater the proportion of juveniles in a population, the more nearly balanced is Table 33.—Shooting losses, as measured by per cent of banded ducks recovered in year of banding, and drake percentage in the population of each of seven species of ducks. Per CrNT OF NuMBER OF Banpep Ducks DRAKE SPECIES Ducks BAaNnDED* RECOVERED IN PERCENTAGE IN YEAR OF PopuLaTiont BaNnDING* Dabbling Ducks Malland's S¥ cen. ett eon eae 22,636 10.0 52.6 Pa oe he eer ere 2,020 8.7 54.6 Pita vos oe Staea ee eee 9 O51 6.1 59.4 Shoveler so: 206 ie ek ese oe ak 749 5:9 60.1 Diving ducks ReaieA separa kae ns so ee toe eee 2,067 13.1 60.2 Canvasbackee <4 702 P28 sci Tae tee 531 1252 66.4 Lesser aeaues 220. 63 a ES ees tts 6,567 6.7 69.5 *Data from waterfowl bandings on Canadian breeding grounds by Ducks Unlimited (Cartwright & Law, 1952:10-1). 4. {Data from summary column, table changes take place in the sex ratios of the yearling class of a duck population. Mor- tality factors that operate through most of the first year of life affect the two sexes about equally or the drakes slightly more than the hens. Available information is not sufficient to permit appraisal of the influence of predation on sex ratios. How- ever, during the breeding season appreci- able losses occur among hens; these losses, most of which appear to be attributable to predation, agricultural operations, and nat- ural stress, may account for the predomi- nance of drakes in the adult class. Sex Ratios and Age Composition of Populations The age composition of a duck popula- tion is reflected in its sex ratios. Because of an approximate balance between the sexes in the juvenile class and an appre- ciable imbalance in the adult class, the greater the proportion of old birds in any given population, the greater is apt to be its sex ratio. Some species of ducks are consistently more productive than other species. hence, high mortality rates. An inverse relationship between shoot- See beeps The Most of the highly productive — species have high shooting losses and, — ing losses and the size of the drake seg- ments is shown in table 33 for four spe- _ cies of dabbling ducks. The higher the ~ shooting loss, the smaller is the imbal- — ance between the sexes in these species. Some species of ducks suffer excessive hunting losses in the juvenile age class. Mortality in the fall is so high in the juvenile class that birds over a year old greatly predominate in the spring popula- — tions. In these species there is a great im- __ balance in the sex ratios of spring popu- lations. High vulnerability to hunting is shown in table 45 for juveniles of two species of diving ducks, the redhead and the canvasback. Of the redhead, Hickey (1952:80) concluded that, “in the past,” the kill | August, 1961 rate for juveniles has been about 50 per cent, whereas the kill rate for adults has been 20 or 30 per cent; the annual mor- tality rates have been about 70 per cent for juveniles and about 55 per cent for adults. Of the canvasback, Geis (1959: 254-5) reported that the year-of-banding recovery rates (per cent of birds banded that were shot by hunters and had bands recovered within a year of the time of banding) were 22 per cent for juveniles and 14 per cent for adults; the annual rates for mortality from all causes were 77 per cent for juveniles and 35 to 50 per cent for adults. Mallard drakes banded as juveniles in Illinois had a first-year mortality rate of about 55 per cent; mal- lard drakes banded as adults had a first- year mortality rate of 36 per cent and an average mortality rate of about 40 per cent (Bellrose & Chase 1950:8-9). The high mortality rate in the juvenile class of redheads and canvasbacks has re- sulted in relatively large numbers of old birds in the breeding populations of these species and consequently a large prepon- derance of drakes, table 33. Extremely large drake segments noted in lesser scaup populations are evidently not related to high juvenile mortality re- sulting from hunting. The vulnerability rate of juveniles in this species, table 45, is insufficient to account for the large im- balance between the sexes, table 33. The causes of the imbalance seem to be (1) low shooting pressure on the species, ta- ble 45, (2) a low reproductive rate, table 62, and consequently (3) a relatively small number of juveniles in the popula- tion, table 53. Variations in the age composition of waterfowl populations are largely respon- sible for variations in sex ratios among species of ducks. Sex ratios of various species of ducks in the spring in North Dakota, table 24, indicate that the mal- lard has relatively the largest number of yearlings in its breeding populations; this species is followed in order by the pintail, shoveler, redhead, blue-winged teal, ring- necked duck, baldpate, canvasback, lesser scaup, and ruddy duck. The Question of Surplus Drakes It seems reasonable to question the value of those drakes in excess of the BELLROSE et al.: SEX RATIOS AND AGE RATIOS 427 number needed to provide mates for the hens in waterfowl populations. In the event such drakes do not play an essen- tial role in species survival, an effort should be made to provide for their utili- zation. While drakes outnumber hens in all species studied, drakes occur in relatively greater numbers among the diving ducks than among dabblers, table 24. Exam- ination of available knowledge on the re- productive biology characterizing these two subfamilies reveals nothing which suggests that extra drakes may be more essential to the maintenance of popula- tions of diving ducks than of dabblers. The hens of diving ducks engage in less renesting activity than do the hens of dabbling ducks, and some observers feel that diving duck drakes tend to be more persistent in remaining with nesting hens than do the drakes of dabbling ducks. Spe- cies differences in this respect were ob- served among dabbling ducks by Sowls (1955:101), who wrote that while late-season or renesting courtship flights of mallards, gadwalls and pintails were common, we seldom saw them in the shovellers and blue-winged teal. I suspect that the difference occurred because of the length of time the drakes stayed with their hens after the clutches were laid. Blue-winged teal and _ shoveller drakes did not abandon their hens until incu- bation was well advanced; while mallard, pin- tail and gadwall drakes abandoned their hens shortly after the clutches were completed. Robert I. Smith of the Illinois Natural History Survey (personal communica- tion, December 9, 1960) also observed that blue-winged teal and shoveler drakes tend to remain with their hens longer than do the drakes of mallards, pintails, and gadwalls; in exceptional cases, mallard, pintail, and gadwall drakes may remain with their hens throughout and even be- yond the incubation period. On the breed- ing grounds, drakes outnumber hens to a greater extent among pintails, blue-winged teals, and shovelers than among mallards and gadwalls, table 34. A pattern of sorts seems apparent here, but it does not afford obvious support of a need for extra drakes in reproduction. The superficially excessive number of drakes may be significant to population dynamics among waterfowl in ways which are not directly related to the in- surance of successful reproduction. At 428 Ittinois NATURAL History SurRVEY BULLETIN times, harassment of nesting hens by idle drakes may result in an important amount of nest desertion and possibly a reduction in productivity. Along with the severe stress of reproductive activity, harassment by drakes may contribute indirectly to mortality among hens. It is conceivable, too, that, if extra drakes are truly sur- plus, they may also create undesirable stress by occupying space and consuming food essential to the welfare of the pro- ductive segment of the population. Perhaps insight into the value of extra drakes could be obtained through an ex- perimental procedure designed to reduce the number of drakes in a subpopulation of a species having a large drake segment. Re- duction of drake numbers could possibly be accomplished by deliberate hunting of drakes in places and at times when they were concentrated apart from the hens or when they could be decoyed from the hens and brought within shooting range. Tep- lov & Kartashev (1958:159, 161), re- porting on observations made on the Oka State Sanctuary and on adjacent shooting areas in Russia, indicated that hunters are “permitted in spring to obtain the drakes of all species and also geese on passage. The most general method of ob- taining waterfowl in spring is the shoot- ing of Mallard drakes which go to a de- coy duck.” In Russia, the killing of fe- male ducks is forbidden in spring. Such an experiment as that outlined above would meet the added objective of deter- mining whether regulated hunting might be directed at what is possibly a truly ex- pendable part of the waterfowl popula- tion. Sex Ratios as Measures of Production Because sex ratios reflect the age com- position of a duck population, analysis of year-to-year differences in the sex ratios of a species offers a method of diagnosing the yearly changes in production. Also, be- cause sex ratios for each species of water- fowl vary from season to season within any year, as a result of hunting and nat- ural phenomena, the sex ratios obtained during a particular season (fall, winter, spring, or summer) should be compared with the sex ratios obtained during only corresponding seasons of other years. A Table 34.—Drake percentages in 12 species of ducks observed in the breeding grounds region of North America, 1935-1942, 1947—1950.* Norts Dakota MANITOBA MINNESOTA SASKATCHEWAN SPECIES Bie | SOC eel arlene Ml evans 53.9 62.8] 60.6f| 61.91] 50.0 | 50.0 | 51.1 “BSS 153.3 1-8059. | 162: 5. 74.34] 77.14] 58.71] 51.3 | 56.5 5552 1:54:57 | S75 Mallard... x) IE bee Gadwalleic ee te oa oe Baldpates.s cosets sie Pintail.... Green-winged teal...... "50.6 | 61.7 ay RGR om ce eect ap ate ee Mg) ALS Wh yee base 52.5 | 56.8 55.0 | 55.4 | 50.8 59a S78 Blue-winged teal............... 53.2 Shaveler.: sere nos 56.6 | 51.9 | 58.6 | 53.3 58.8 | 64.6 | 57.9 54.4 | 61.4 58.5 | 57.6 | 58.9 Vol. 27, Art. 6 © 55.5 [Retro a (atta fe eeeg eee per ae Ring-necked duck...... 60.4 | $5.1 66.6 | 74.2 | 50.0 | 69.3 | 66.3 | 65.0 | 64.3 | 66.6 |...... 60.9 | 61.0 | 74.4 | 70.6 | 69.4 | 62.0 | 69.0 | 67.7 | 64.3 | 76.0 | 74.0 77.4 | 69.5 | 69.6 Canvasback......... S71 61.1 Lesser scaup.... Ruddy duck... (1935:278; 1938:22); Minnesota, Erickson (1943:27); Manitoba, Hochbaum (1944:15); North Dakota, M. ce (personal communicati: : Saskatchewan, Furniss regions e Servi *Sources of data for the various C. Hammond, U. S. Fish and_Wildlit August, 1961 75 50 PER CENT 25 1941 1945 1943 1939 BELLROSE et al.: SEX Ratios aND AGE RATIOS 429 Hens loud e —-—— Juveniles Hens Juveniles rv @ ee 1947 1949 1951 1953 1955 1959 Fig. 9.—Year-to-year changes in the hen percentage and in the juvenile percentage in mal- lards checked in hunters’ bags in the Illinois River valley, 1939-1955 and 1959. Percentages have been adjusted so that the means for juveniles and hens are equal. comparison of the sex ratios in the sum- mer of one year with the sex ratios in the winter of the same or another year would be biased by the disproportionate hunting losses of juveniles, which have approxi- mately balanced sex ratios. As a means of measuring yearly pro- duction, sex ratios have certain basic ad- vantages over age ratios. For many spe- cies of ducks, such as the divers, age ratio data, derived from bag checks during the autumn, are difficult to obtain in ade- quate numbers. For the most important species, it is much easier to obtain large samples of sex ratio data from field ob- servations than to obtain large samples of age ratio data from bag inspections. Less skill is required to determine the sex of a duck in nuptial plumage than the age of a duck in any plumage. To test the validity of sex ratios as cri- teria of duck production, we have made a comparison, fig. 9, of sex ratios with age ratios, which are direct reflections of pro- duction. Both ratios were obtained from mallards killed by Illinois hunters in 1939- 1955 and 1959. We have also made, for several species of ducks, comparisons of sex ratios derived from observations on the breeding grounds, table 34, with the number of juveniles per hen killed in Illinois, table 62. As shown in fig. 9, the sex ratios (per cent hens) and the age ratios (per cent juveniles) obtained from mallards killed by Illinois hunters differed markedly in several years. The fluctuations in age ra- tios tended to be of greater magnitude than those in sex ratios; the peaks were higher in age ratios than in sex ratios, and the troughs were deeper. An over-all correlation of +0.59 suggests that only fair agreement exists between the sex ra- tios and the age ratios. We conclude that sex ratios derived from bag inspections provide a fair index to productivity but not so good an index as age ratios. Sex ratios obtained on the breeding grounds, table 34, do not appear to pro- vide a more reliable index to production than sex ratios calculated from bag in- spections in Illinois. Data for the breed- ing seasons of 1935-1942 and 1947-1950 (except certain data from Furniss, table 34) show that the drake percentages for the mallard, gadwall, pintail, green- winged teal, and ring-necked duck did not, in any season for which figures are available, deviate from the average for the species by as much as 5 per cent. This lack of deviation indicated relatively sta- ble populations; data in table 62, showing the number of juveniles per adult hen for the years 1946-1949, indicated increasing 430 populations for all of the above-men- tioned species except the gadwall. AGE RATIOS Two commonly used indicators of waterfowl production are brood densities (the number of broods per unit of area on the breeding grounds) and age ratios (the mathematical relationship between adults and juveniles old enough to fly). Brood density surveys supply informa- tion of value for making preseason ad- justments in hunting regulations. How- ever, data on brood densities are not be- lieved to constitute precise indices of pro- duction. Substantial proportions of the broods present in an area are missed by observers employing survey techniques us- ually considered practicable (Anderson 1953:8-10). Correction for unobserved broods may never yield to reliable stand- ardization, for the percentage of broods not found by observers varies with many factors such as time of day, time of season, habitat, area, and waterfowl population densities. Age ratios are believed to afford a more promising basis than brood counts for measuring waterfowl production, although they, like data on brood densities, are seldom true indices of production. This section of the paper is written with the intention of opening the way to a more effective use of age ratios in wa- terfowl management. The following as- pects of age ratios and their use are con- sidered: age criteria, sampling methods for obtaining age ratios, seasonal and re- gional variations in age ratios, factors tending to bias age ratios, age ratios as measures of production, environment in relation to production, production in dif- ferent species, and the place of age ratios in population management. Age Criteria In 1938, when biologists of the Delta Waterfowl Research Station at Delta, Manitoba, and of the I]linois Natural His- tory Survey at Havana, IIlinois, initiated waterfowl research programs involving the inspection of large numbers of ducks bagged by hunters, the need for finding consistently reliable external characteris- tics by which to separate juveniles from ILttino1is NATuRAL History SurveEY BULLETIN Vol. 27, Art. 6 adults was recognized. The best external indication of age known at that time had been pointed out by Pirnie (1935:275). It was based on the appearance of the tips of tail feathers, those of adults being rounded or pointed, those of juveniles be- ing blunt or notched. However, in the mallard, an important species in Illinois and at Delta, young birds were known to replace their juvenile feathers with adult feathers early in the fall; hence, they could not be accurately aged by this char- acteristic throughout the hunting season. In some species, notably those in the genus — Aythya, the tail feather criterion was found to be more persistent than in the mallard, but, even so, it was not reliable throughout the hunting season. During the fall of 1938, biologists at the Delta and Illinois stations searched for some characteristic by which to sep- arate juveniles from adults in the mallard and other early-molting species. search at Delta was concentrated on plum- age, while that in Illinois was concerned with a character, pointed out by Tice- hurst (1938:772-3) as being related to immaturity: striae “at the tip of the nail of both upper and lower mandibles.” The Illinois group also investigated various parts of the skeleton that might exhibit differences in ossification between juve- niles and adults. At that time, neither group was successful in the search for a — characteristic by which to separate ducks into the two age classes. In the following winter, Gower (1939: i " 427) called attention to the bursa of Fa- bricius as a criterion of age in ducks. A short time later Hochbaum (1942:301), aided by the findings of Gower and the work of Owen (1866:244—-5), learned — that juvenile drakes of 5 to 10 months of — age could be separated from adult drakes by the size of the penis, fig. 1. This find- ing, put to use in the summer and fall of 1939, provided a method of differentiat- ing between juveniles and adults of both The new method — proved faster and easier to use than the — bursal method. Also, it provided for ac- — curate separation of drakes from hens in ~ all stages of plumage. However, the bursa — live and dead drakes. was found to persist for several weeks after the transition from juvenile- to adult-type penis and therefore provided a — The i August, 1961 basis for separating juveniles from adults over a longer period of time than that af- forded by the penis. Hochbaum (1942:303-4) pointed out that the oviduct, which opens into the cloaca in adult females, is sealed by a membrane in immature females, fig. 1. Wildlife technicians in Illinois have found 80 70 60 50 40 PER CENT JUVENILES 30 20 1939 1941 1943 1945 BELLROSE et al.: SEX Ratios AND AGE RATIOS A McGinnis Slough /+/y \ glake Chautauqua 1947 431 collected from duck hunters and shipped to a central point for interpretation by trained personnel. Sampling for Age Ratios Data on the age ratios of ducks may be obtained by examination of birds trapped for banding, shot by hunters, or killed by a Valley 1953 1957 1955 1949 195) Fig. 10.—Year-to-year changes in the juvenile percentage in mallard drakes trapped at Mc- Ginnis Slough and at Lake Chautauqua and in mallards checked in hunters’ bags in the Illinois River valley, 1939-1957. that, until at least mid-January, the pres- ence of a closed oviduct and a bursa un- failingly indicates a juvenile hen. Occa- sionally, a hen is found that shows an open oviduct and a small bursa; such a bird is considered adult. Most wildlife technicians have restricted their aging of hens to individuals that have been bagged by hunters. However, Hanson (1949) developed a technique that can be used for aging live females in both ducks and geese. In 1958, after completion of most of the field work for the study reported here. Carney & Geis (1960:376-9) found that, in certain species of ducks, juveniles and adults could be identified with a high de- gree of accuracy on the basis of differ- ences in the wing plumage. The technique described by these authors makes possible the extensive sampling of age ratios of ducks in all four flywavs of North Amer- ica. Large numbers of wings could be disease. It seems desirable that the rela- tive merits of these sources of data be ap- praised. In the present study, all three sources of data were used for obtaining age ratios. Examination of Trapped Ducks.— A comparison of the age ratios of mallard drakes trapped at Lake Chautauqua, table 35, and the age ratios of mallard drakes and hens taken by hunters in the Illinois River valley, table 36, discloses marked disparity in the number of juveniles per adult between the trapped ducks and the harvested ducks. The data show rela- tively fewer juveniles among the drakes trapped at Lake Chautauqua than among the ducks taken by hunters in the Illinois River valley, tables 35 and 36 and fig. 10. However, among drake mallards captured at McGinnis Slough in traps similar to those used at Lake Chautauqua, a higher proportion consisted of juveniles, table 37 and fig. 10, than among mallard drakes 432 trapped at Lake Chautauqua or mallards bagged in the vicinity of that lake. Despite marked differences in the size of samples between trapped and shot mal- lards, the two sampling procedures indi- cated similar year-to-year trends in age ra- tios, fig. 10. The statistical correlation in the annual changes in age ratios between mallard drakes trapped at Lake Chau- tauqua and mallards shot along the IIli- nois River was found to be significant 70 65 60 55 50 PER CENT ADULTS 45 40 35 30 3rd OCTOBER 2nd 4th Ist Ittinois NATURAL History SurvEY BULLETIN Bag Checks 2nd NOVEMBER Vol. 27, Art. 6 (r=+0.96, 13 d.f.) at the 99 per cent level. Mallards inspected in hunters’ bags in the Illinois River valley (1939-1949) and mallard drakes taken in traps at Lake Chautauqua (1939-1944 and 1947) showed similar trends in age ratios for most of the hunting season, fig. 11. The trends tended to be parallel except in early December. The correlation between age ratios calculated weekly for the samples Trap Catches oe Differences 2nd DECEMBER 3rd 4th Ist 3rd Fig. 11.—Week-to-week changes in the adult percentage of the autumn flight of mallards in Illinois, as indicated by two sampling methods: checks of mallards in hunters’ bags and inspec- tion of mallard drakes caught in banding traps. Bag data are for the Illinois River valley, 1939- 1949; trap data are for Lake Chautauqua, 1939-1944 and 1947. EEE LL August, 1961 BELLROSE et al.: of trapped and shot mallards was signifi- cant (r=+0.94, 7 d.f.) at the 99 per cent level. Behavior may well account for the large juvenile proportion in the mallard drakes taken in traps at McGinnis Slough, fig. 10, and the small proportion in those taken in traps at Lake Chautauqua. As discussed Sex Ratios AND AGE Ratios 433 under sex ratios, mallard drakes were ob- served to be more aggressive than hens in pushing their way into the traps at Lake Chautauqua. Perhaps adults shouldered young birds aside in aggressive efforts to get at the bait. Lake Chautauqua had a much greater density of mallards and com- paratively less natural food than McGin- Table 35.—Number of juveniles per adult among mailard drakes trapped and banded at the Chautauqua National Wildlife Refuge, near Havana, Illinois, 1939-1944 and 1947—1959, NuMBER OF yc DRAKES TRAPPED AND BANDED _ SB Da ee Mees Se i cae 2,574 2 EQ) eo 4,262 MERI Pe cre ee ericistechacees 3,200 _ tabs = GA nec oon Ber eee 4,859 AL ea ae ee 4,655 PR pera eh. Sue ees sc Sd 2,734 EY) cuca ae Oe 1,481 EU ae Oe ee pce? MP a rs ooh ora 15) onclce See SE Eee ee 1,984* ES Se art 9 oan 3, 801* BEL mae er che a seas 4,493 PSM eye RN es Oa bss 1,048 Ee ee eee as 901 USS 3 GAS eee 998 UG 5 MG ee 632 | DET pe aoe, Sea ne Ceo 856 ETS oH ye A le ee 736 LESS SARS Bes ates eae 93 APPROXIMATE Per CENT JUVENILES 95 Per Cent JUVENILES Per ADULT CONFIDENCE Limits 42.3 0.73 0.67-0.80 S79 0.61 0.57-0.66 34.1 0.52 0.47-0.56 35.3 0.55 0.51-0.58 40.6 0.68 0.64-0.73 22.6 0.29 0.26-0.32 41.1 0.70 0.62-0.78 eyo 18 LOU 27) 331 0.50 0.45-0.54 34.1 0.52 0.47-0.57 Sli 0.61 0.56-0.65 53.7 1.16 1 09-1E 24 44.9 0.82 0.72-0.92 34.4 0.52 0.46-0.60 41.1 0.70 0.61-0.79 50.1 1.01 0.86-1.17 29.6 0.42 0.35-0.49 25.8 0.35 0.28-0.42 De Ost 0.04-0.18 *This figure differs from the corresponding figure in table 39 because it includes ducks banded with reward bands, which have shown a higher rate of return than standard bands (Bellrose 1955). Table 36—Number of juveniles per adult among mallard drakes and hens checked in hunters’ bags in Illinois, principally the Illinois River valley, 1939-1955 and 1959. NuMBER OF YEAR Ducks CHECKED DSSS ee ee ein ao eae 2,261 D/O) ca eee Seek eee 3, 564 CSAS oe, So aul et ea er 4,481 TOLD. 5 Fede eee ee 1,809 METEOR te ne oe a: 1,422 Oe as RON et ie eae 2,167 OCS tee dee Seen Se eee ee 2,047 Se i ce ere ae Sie ATL OS Cen Re Pa eee! 814 1 oA a Oe ee ee eo 1,215 SIO) ioe SI ea Ste Es ee 597 SEXO As ae ee 581 IOS i Ee eS ee 819 DDD 1 een a Se OS 1,209 SIS) ane een cae ar £052 DIS Hare Sa a) Lo Se 458 ISSN Soe a Re aR 746 SO Pyare aera ct ts Me aoe ae 247 APPROXIMATE Per Cent JUVENILES 95 Per Cent JuveENILES Per ADULT CONFIDENCE Limits 59.1 1.45 1.32-1.58 Pood 1.42 age ile Sy) 50.3 1.01 0.95-1.08 54.2 1.18 1.07-1.30 66.0 1.94 Po—2 eke 54.3 1.19 1.09-1.30 43.9 0.78 0.67-0.92 2565) a5 1.11-1.40 70.3 2.36 2.03-2.78 76.0 3.18 2.78-3.63 49.2 0.97 0.79-1.18 60.4 Ios) 1.28-1.82 63.1 egAl 1.48-1.99 62.3 65 1.46-1.87 59.6 1.48 1.34-1.63 47.6 0.91 Oe Jalal’ 64.1 1.78 1.34-2.22 Soe) 0.34 0.30-0.38 434 ILLino1s NATuRAL History SurvEY BULLETIN Vol. 27, Art. 6 Table 37—Number of juveniles per adult among mallard drakes trapped and banded at McGinnis Slough, Cook County, Illinois, 1940-1947. NuMBER OF APPROXIMATE Vie DraKES Per Cent JuveENILES 95 Per Cent TRAPPED JuveENILES Per ADULT CONFIDENCE AND BANDED Limits 1940 tes an se d pcr emer iste 267 68.5 2.18 1.68-2.85 sek. 5 Catan ates, Cera Ne ae 195 D955 1.47 1.11-1.98 Ne PASS ed rear Si a 1,128 69.0 Dape 1.96-2.54 i % ae SEEN A 2 1,922 67.1 2.04 1.85-2.25 Ae eo Uae tas eeearaionsis 967 65.9 eS 1.69-2.22 hoc a oe naning + Lars ube 1,492 54.9 1522 1.09--1.36 1966 3. esate em a aitoriersit 860 61.5 1.60 1.39-1.85 W987 5 Pe cdne aabtok cos aisisiers 556 74.3 2.89 2.40-3.55 nis Slough. This situation may have re- sulted in greater competition for food at Lake Chautauqua and consequently greater aggressiveness on the part of the adult mallard drakes. The greater fre- quency of juvenile drakes in traps at Mc- Ginnis Slough than at Lake Chautauqua may have resulted in part from greater wariness on the part of adult drakes. With an abundance of natural food at McGinnis Slough, many adults may have avoided the traps or ignored the foods they contained. Apparently, in one case (Lake Chautauqua) the traps were se- lective for adults while in the other (Mc- Ginnis Slough) they were selective for juveniles. There was a significant correlation at the 99 per cent level between the age ratios of drake mallards trapped at Mc- Ginnis Slough, table 37, and the age ra- tios of mallards taken by hunters in the Illinois River valley, table 36 (r= +0.93, 6 df.). Data obtained from retrapping mallard Table 38.—Number of adult and of juvenile mallard drakes trapped and banded and thei drakes previously trapped and banded at Lake Chautauqua, table 38, indicated that — the banding traps there were selective, sometimes for juveniles and sometimes for adults. During the period October +24, juveniles re-entered the traps with greater — frequency than adults (X?=31.14, 1 d.f., _ significant at the 99 per cent level). In contrast, during the period October 25-_ December 25, adults re-entered the traps — with greater frequency than juveniles (X?=12.90, 1 d.f., significant at the same — level). These retrap data showed that early in the season, when mallard numbers — were low and food competition was at a minimum, banding traps were selective for — juveniles, but, when mallard numbers — increased and food competition became — greater, the traps were selective for adults. The bulk of the mallard population ar- rived in Illinois after October 25, and the banding traps at Lake Chautauqua were on the whole highly selective for adults. A correlation, significant at the 99 per cent level, was found in each year for the — ret pS per cent retrapped during two periods at the Chautauqua National Wildlife Refuge, near Havana, Illinois, 1940—1943. iy / » ADULTS JUVENILES - ates RaTIo OF ki Per C ie Number Number or AGI 4 oa ReETRAP- PeRioD Per Cent Per Cent Pin ce x d Re- T 7 Re- ER CENT pie : Re- q trapped oe ; Re- q trapped or J Re rappe rappe NILFS RE Banded Banded TRASEGM Oct. 4-24....... 1,305 297 22.8 1,026 340 28.2 1:1 Oct. 25-Dec. 25.| 9,322 991 10.6 5,265 462 8.8 1:0.83 August, 1961 BELLROSE et al.: SEx Ratios AND AGE RaTIOS 435 Table 39.—Comparative vulnerability (to hunting) of adult and juvenile mallard drakes banded at the Chautauqua National Wildlife Refuge, near Havana, Illinois, 1939-1944 and 1947-1952; vulnerability measured by year-of-banding recoveries. Ducks banded with reward bands (Be-lrose 1955) in 1949, 1950, and 1951 were not included in this table. NuMBER OF DRAKES Y EAR-OF-BANDING rig ee nee PER RATIO OF BANDED RECOVERIES Cpe Soe ADULT TO YEAR BONERS JUVENILE VULNER- Adults Juveniles Adults Juveniles Adults Juveniles ABILITY 123) eee 1,486 1,088 65 49 22.9 22:32 Pate0s DAN) See ane 2,647 1,615 132 200 20.1 Sed 1:2.48 MUI she bac 2,110 1,090 57 43 37.0 25.4 1:1.46 j 4D) Se 3,142 il, TAL 216 177 14.6 9.7 hele Sil ES 2,763 1,892 138 146 20.0 13.0 1:1.54 AE ac a eects 2 617 125 56 16.9 11.0 Le 54 Ss 871 610 31 34 28.1 17.9 EATS, J 624 708 5 11 124.8 64.4 1:1.94 1 oe 1,286 silks) 46 53 28.0 MWS Lete24 0 449 359 24 Di 18.7 1)53! 1:1.41 Mer ess vais ss 583 325 20 12 29.2 Dalton 1:1.08 S32 er 2,082 2,411 60 151 34.7 16.0 ew atl 7/ PU Years... 2. 20,160 13,624 919 959 21.9 14.2 1:1.54 relative constancy between the age ratios of mallard drakes banded at McGinnis Slough and of those banded at Chautau- qua (r= +0.98, 5 d.f.), tables 35 and 37. In spite of trap bias, ducks taken in traps are believed to provide a rough in- dex to yearly changes in age ratios. Inspection of Hunters’ Bags.—It became apparent early in the study that juvenile ducks were more readily taken by hunters than were adults. Tests sug- gested that data obtained by trapping and banding ducks could be used to correct for the greater vulnerability of the juveniles. The following equation was used for this purpose : Number of adults banded during current season but before end of hunting season Number of year-of-banding band recoveries from adults Number of juveniles banded dur- ing current season but before end of hunting season Number of year-of-banding band recoveries from juveniles Vulnerability quotient V= An example of the use of the equation with banding data for 1940 in table 39 follows: 2,647 132 20.1 ans aise) 38a Stas 200 Mallards were banded at one or more stations in Illinois each year from Octo- ber, 1939, through 1952, and the data ob- tained were used for determining the yearly variations in comparative vulner- ability of juvenile and adult drakes, tables 39 and 40. Adult drakes banded at Mc- Ginnis Slough, table 40, experienced rela- tively greater losses from hunting than did those banded at Lake Chautauqua, ta- ble 39. The number of juvenile drakes banded per juvenile recovery was about the same at both places. The data indicate that greater hunting pressure was ex- erted on adult drakes banded at McGin- nis Slough than on those banded at Chau- tauqua. Black duck drakes banded at McGin- nis Slough had about the same loss of juveniles to hunting, table 41, as did mal- lard drakes banded there, table 40. Black duck drakes banded at Lake Chautauqua, table 42, like mallard drakes banded there, table 39, experienced a lower rate of hunt- ing loss among adults than did black duck drakes banded at McGinnis Slough, table 41. Apparently, in mallard and_ black duck drakes banded at Lake Chautauqua, the relatively lower hunting losses in adults resulted from the greater protection afforded them outside the banding station area. The Chautauqua National Wild- life Refuge is about 10 times as large as 436 Ittrnois Natural. History SurvEY BULLETIN Vol. 27, Art. 6 Table 40.—Comparative vulnerability (to hunting) of adult and juvenile mallard drakest banded at McGinnis Slough, Cook County, Illinois, 1942-1947; vulnerability measured by year- — of-banding recoveries. NuMBER BANDED Per NuMBER OF DRAKES YEAR-OF-BANDING RatTIOo oF BANDED RECOVERIES Lae pei ADULT TO YEAR oe JuvENILE Te VULNER- Adults | Juveniles | Adults | Juveniles | Adults | Juveniles ABILITY a I ee eee 14D a heen 350 778 26 66 13.5 11.8 1:1.14 1943s her, 632 1,290 21 57 30.1 22.6 1:1.33 12) 7 ieee hte, arte 330 637 33 67 10.0 9.5 1:1.05 19450. et 673 819 38 69 Nideeilh 11.9 1:1.49 19465. Se ee 331 529 20 41 16.6 12.9 1:1.29 1949o asses aes 143 413 8 29 17.9 14.2 Eh PSs AL VeGTS vo. eae 2,459 4,466 146 329 16.8 13.6 1:1.24 Table 41—Comparative vulnerability (to hunting) of adult and juvenile black duck drakes 4 banded at McGinnis Slough, Cook County, Illinois, 1940-1947; vulnerability measured by year- of-banding recoveries. NumBer BANDED PER NuMBER OF DRAKES YEAR-OF-BANDING RatTIo oF BANDED RECOVERIES basso: -BaNDING ADULT TO ECOVERY YEAR JUVENILE VULNER- Adults | Juveniles | Adults | Juveniles | Adults | Juveniles ABILITY ISAO ee ee 33 48 4 6 8.3 8.0 1:1.04 194d AF meee 153 253 10 16 15.3 15.8 1:0.97 1949s. hare eee 231 414 15 32 15.4 12.9 1:1 1948. aticok Broce 259 336 8 16 32.4 21.0 1:15 19446 oe Pree whe. 167 323 16 39 10.4 8.3 1:1,.25 LGA ees 166 296 11 31 1551 9.6 1:257 1946) SO 128 257 6 18 DAS 14.3 1:1.49 194 Fae ses 117 271 1 i All years..... 1,254 2,198 71 167 U7 af, NE Be: PE ee Table 42.—Comparative vulnerability (to hunting) of adult and juvenile black duck drakes S banded at the Chautauqua National Wildlife Refuge, near Havana, Illinois, 1939-1944 and 1947-1950; vulnerability measured by year-of-banding recoveries. ‘ NuMBER BANDED PER NuMBER OF DRAKES Y EAR-OF-BANDING Ratio oF BANDED RECOVERIES Year or De ADULT TO YEAR EO JUVENILE VULNER- Adults | Juveniles | Adults | Juveniles | Adults | Juveniles ABILITY MGSO ee reels 55 47 2 2 27s 2555 bE Is 1940S. ed Boke ot 93 68 4 6 2303 19 Us 1:2.06 1 AOE ae aps sea ae on 181 148 1 4 181.0 37.0). |... 19409 og ee 225 123 22 20 10.2 6.2 1Ls1265 | ICSF ie esa aCe ie 188 115 9 9 20.9 12.8 1:1.63 194e a re cores 119 66 I] 8 17.0 8.3 1:2.05 PORTE eS Pett 70 63 ues cbs oy otaie’ dacs | Sala ao x [seaweeds cen nae SOAS on. Peek 39 7. | EE RO Ie Uae EE Ue 1940 eee ae sie 216 165 3 11 72.0 15.0 1:4.80 L950. yee see. 98 12 4+ 1 24.5 12.0 1:2.04 AN Years So 1,284 855 52 61 24.7 14.0 1:1,76 August, 1961 McGinnis Slough; also, several other ref- uges occur within the 25- to 30-mile feed- ing radius of mallards congregating at Chautauqua, whereas none occurs within that distance of McGinnis Slough. It seems evident that adult mallards and BELLROSE eft al.: SEX Ratios AND AGE Ratios 437 drakes became less vulnerable, table 44, presumably as a result of increased experi- ence with hunters. During the early part of the season, the juveniles were bagged about four times as readily as adults; late in the season they were bagged only about Table 43.—Comparative vulnerability (to hunting) of adult and juvenile blue-winged teal drakes and hens banded in Illinois at McGinnis Slough, Cook County, 1942-1947, and at Moscow Bay, Mason County, 1949-1951; vulnerability measured by year-of-banding recoveries. NumsBer oF Ducks Y EAR-OF-BANDING ae ear PER RATIO OF BANDED RECOVERIES nea BuEING ADULT TO YEAR eee JUVENILE VULNER- Adults | Juveniles | Adults | Juveniles | Adults | Juveniles ABILITY Be niaie Site 156 535 i 29 22.3 18.5 eilavil a hoe 2c. 131 424 2, 16 65.5 26.5 DA Ey kt, 304 534 8 45 38.0 11.9 1:3.19 5D 193 444 8 23 24.1 19.3 feat 25) AG eee 90 686 1 9 90.0 76.2 1:1.18 1G) 65 234 1 6 65.0 39.0 1:1.67 ED ene 169 1,071 0 BAF allt etek Err Bi Site alba ea BWP as chee cy sc, 152 505 A Dp. 76.0 23.0 1:3.30 Reo sos. es 210 1,189 4 33 SDS 36.0 1:1.46 fll years. ... 1,470 5,622 33 Di 44.6 Deeg eee, black ducks at Chautauqua made good use of their acquired knowledge of pro- tected areas. Blue-winged teals banded at McGinnis Slough and Moscow Bay experienced greater differences between the two age groups in vulnerability to hunting, table 43, than did mallard drakes banded at Lake Chautauqua, table 39, or McGinnis Slough, table 40. Although blue-winged teals are generally considered to be less wary than mallards and black ducks, the development of wariness by juvenile blue- winged teals may be as rapid as that by juvenile mallards when the birds are sub- jected to hunting. Vulnerability in the blue-winged teal, as in other species, prob- ably is related to the amount of experi- ence that juveniles have had with hunters. Most of the juvenile blue-winged teals arrive in Illinois in advance of the open season in the northern zone and therefore are inexperienced with hunters at the time of their arrival. Most juvenile mallards and black ducks have been subjected to hunting by the time they reach Illinois. Data collected in 1940, 1942, 1943, and 1952 showed that, as the hunting season progressed in Illinois, juvenile mallard one and one-half times as readily. Thus, age ratios obtained from hunters’ bags on major wintering grounds would be less biased by the greater vulnerability of juve- niles than samples taken earlier on breed- ing or migration areas. The year-to-year variations in the amount of hunting ex- perience juveniles receive before they reach Illinois may be an important factor in de- termining the year-to-year variations in the vulnerability of juveniles in this state, ta- bles 39 and 40. Mallard age ratios ob- tained from bag checks on the breeding grounds appear to be the ratios most biased by juvenile vulnerability, and those ob- tained on the wintering grounds are prob- ably the least biased, table 52. The relative vulnerability of juveniles and adults of several duck species have been calculated from recovery of birds banded on the Canadian breeding grounds, table 45. The recovery data for the teals and the shoveler show either no greater vulnerability among juveniles than among adults or a greater vulnerability among adults. However, as recovery data for blue-winged teals banded in Illinois over a period of several years show a markedly greater vulnerability of juveniles, table 438 43, local conditions affected I_uinors NATURAL History SuRVEY BULLETIN it is suspected that some unusual Canadian Perhaps the bandings of these three species. Vol. 27, Art. 6 many juvenile teals and shovelers lost bands, for, until 1957, the banding office’ at the Patuxent Research Center, Laurel, Table 44.—Seasonal change in comparative vulnerability (to hunting) of adult and juvenile mallard drakes banded at the Chautauqua National Wildlife Refuge, near Havana, Illinois, in 1940, 1942, 1943, and 1952. NuMBER OF DRAKES NuMBER OF REcov- ERIES FOR WEEK NumBeErR BaNnDED Per REcoverRY Adults | Juveniles | Adults | Juveniles 0 Oo WO oa eee i 1 6 493.0 75.3 8 24 21255 51.0 9 28 363.1 75.4 14 34 350.9 98.9 35 55 181.7 82.9 29 51 276.7 119.9 48 78 203.2 90.1 73 88 141.4 84.1 70 96 149.5 78.0 65 51 163.5 149.5 31 35 343.0 218.1 30 15 354.5 509.0 22 24 483.4 318.1 5 6 2,126.8 PAP) 5) 2 (Onl PREeNeReR Ro 442 591 BANDED Wek eee 5 Adults Juveniles Oct “4-108 x. 112 90 Oces TIS eee 493 452 Get: 19-245 25. 1,700 1,224 Oct: 95-Ble 3, 268 ean Novia tle ivicc a's 4,913 3,363 Novae8-l42... 6, 360 4,561 te | ee 8,025 6,116 Nov. 22-28..... 9,752 7,025 Nov. 29-Dec. 5.| 10,319 7,398 Decin6=12).5 10,464 7,483 Dec. 13-19..... 10,629 7,626 Dec. 20-26..... 10,634 Waoo> Dec. 27-Jan. 2 10, 634 7,635 i ft es 2. aramid 10,634 7,635 Jan, 10-16: -... 10,634 7,635 Jan. 17-23. 10, 634 7,635 All weeks Tolan. 10,634 7,035 POCTERE Poa aha SO feat eas Ok Ds eek es dlal| see ES ee RaTIo oF ADULT TO — JUVENILE VULNER- ABILITY ee 00 ht tn ee Beal — ee An UNROOR NW SH SxuSS& Roa — ee oe _eo . ee ee EO ee Table 45.—Comparative vulnerability (to hunting) of adults and juveniles, both drakes and hens, of 10 species of ducks banded by Ducks Unlimited* in the prairie provinces of Can- ada, 1946-1954; vulnerability measured by year-of-banding recoveries. NumsBer OF Ducks Y EAR-OF-BANDING BANDED RECOVERIES SPECIES | Adults | Juveniles | Adults | Juveniles Mallard... 28 4,672 10,159 Gadwall........ 133 351 Baldpate....... 491 765 Pintallen nso: oye AY 3,013 Green-winged fealie rene 391 1223 Blue-winged rr) RO ene eae 1,809 2,716 Shoveler....... iW 261 Redhead....... 715 358 Canvasback.... 50 125 Lesser scaup... | 393 1,716 NuMBER BANDED PER Y EAR-OF-BANDING RECOVERY Adults Juveniles RaTIo OF ADULT TO JuvENILE VULNER- ABILITY *Compilation by William Leitch, Chief Biologist, Ducks Unlimited; data are from bandings by field personn: qualified to separate adult and juvenile ducks. {This ratio probably incorrect, perhaps partly as a result of loss of bands by newly banded juveniles and unusu ally heavy losses among juveniles ‘between banding and opening of hunting season. August, 1961 BELLROSE et al.: SEX RaTIOS AND AGE RATIOS 439 Maryland, recommended size 6 for the shoveler, although a size 5 is large enough for that species. Many banders used size 5 to mark green-winged teals, although size 4 is the proper size. Perhaps natural mortality was unusually severe in the young teals and shovelers between the time of banding and the opening of the hunting season; very few bands are recov- ered from ducks that are not bagged by hunters. Still another possible explana- tion for unexpectedly low relative vulner- ability rates for juveniles on the Canadian breeding grounds has been posed by Rob- ert I. Smith of the Illinois Natural His- tory Survey. Smith has observed on the breeding grounds that fall flocking be- havior of juveniles differs from that of adults. Prior to migration, juveniles tend to congregate, while many adults remain as single hens of male-female pairs. The nature and time of this flocking behavior, Smith believes, varies with species and with the success and duration of the nest- ing season. Flock size is probably inverse- ly correlated with vulnerability, thus tend- ing to give greater protection to the con- gregated juveniles than to the single adult hens or paired adults. Band recovery data showed pronounced differences among species in the vulner- ability rates of juveniles banded in Can- ada, table 45. Among species other than the teals and the shoveler, juveniles were least vulnerable to the gun in the mallard and most vulnerable in the redhead. Other data obtained from bandings at national wildlife refuges also disclosed wide varia- tions in juvenile vulnerability; they showed the mallard with a comparatively low juvenile vulnerability rate, followed by the pintail, and showed the redhead with the highest vulnerability rate. Thus, the gun vulnerability of juve- niles compared to that of adults was found to vary by place, time of hunting season, year, and species. Gun vulnerability figures for correct- ing age ratios obtained by checking hunt- ers’ bags in one or more flyways can best be obtained by banding adults and juve- niles in southern Canada just prior to the opening of the hunting season. When adequate data from banded ducks are available, they provide a means of testing for and, if necessary, correcting for the relatively greater vulnerability of juveniles. We believe that age ratios of ducks obtained from bag samples and cor- rected for the greater vulnerability of juveniles offer the best means of deter- mining the adult-juvenile composition of duck populations. However, before these data are used to evaluate production, an appraisal of the influence of season and geography on age ratio samples is needed. Examination of Disease Victims. ——At times, age ratios have been obtained from large samples of ducks which have been victims of disease. During fowl Table 46.—Juvenile percentages among botulism victims in five species of ducks at the Bear River Migratory Bird Refuge, Utah, during late summer, 1952.* MALLARD PINTAIL Gee nSeS SHOVELER BALDPATE EAL PERIOD Per Per Per Per Per Num- | Cent | Num-| Cent | Num- | Cent | Num- | Cent | Num-/ Cent ber Juve- ber Juve- ber Juve- ber | Juve- ber | Juve- niles niles niles niles niles August Ist week...... 48 39.6 486 Ss OE A A erat AAT Ne Bivona alta A Ny | Se Re 2nd week... . 38 52.6 560 COPS | ile 5 Nearer || eral ecm SMe ed Insc cael tet ne etree Pe eae 3rd week... .. 34 44.1 601 61.7 128 41.4 26 OY Pai |e We 4th week... 87 41.4 | 2,392 50.6 651 42.7 94 46.8 26 38.5 September Ist week...... 29 44.8 | 1,211 44.3 431 43.6 81 | 38.3 65 BPs 2nd week... . 38 39.5 781 47.1 Silt 47.7 107 42.1 62 46.8 *Calculated from data in a report, “Sex and Age Ratio of Waterfowl Afflicted by Clostridium botulinum, Type C, on the Bear River Migratory Bird Refuge During Summer, 1952,’’ by Jack P. Allen, Utah Cooperative Wildlife Re- search Unit, Logan. 440 cholera epizootics in wild ducks, records have been made of the species and sex af- fected, but little attention has been given to the ages of victims. In Utah, large numbers of waterfowl that were victims of botulism at the Ogden Bay Bird Ref- uge were classified as juveniles or adults by Noland F. Nelson, tables 21 and 22, and ducks lost to botulism at the Bear River Migratory Bird Refuge were sim- ilarly classified by Jack P. Allen, table 46. The degree to which botulism toxin is se- lective for the two age groups has not been investigated. Epizootics resulting in extensive loss of waterfowl cannot be relied upon as de- pendable sources of data on age ratios be- cause of irregular occurrence and site lim- itations. However, advantage should be taken of such occasions for the purpose of obtaining supplementary age data and for investigating the extent to which disease may be selective for age classes. Seasonal Variations in Age Ratios Because adults and juveniles, like drakes and hens, have different migration sched- ules, age ratios calculated for any given area have seasonal variations. Differential migratory movements of adult and juvenile age groups often orig- inate on the breeding grounds, where most of the adult drakes of most species leave their mates early in the nesting period to congregate on large lakes and marshes; these areas may be in the immediate breed- ing area or up to hundreds of miles dis- tant. After the broods become independ- ent, the hens leave them and molt their flight feathers but usually remain in the area where they nested (Hochbaum 1944: 119, 122). Hens that have been unsuc- cessful in their nesting efforts may join the drakes on the lakes or marshes, where they molt. Certain large lakes and marshes on the breeding grounds serve ducks as gathering areas preceding southward migration. One of these areas is the Delta Marsh at the south end of Lake Manitoba, Canada. The number of juveniles per adult among mallards in hunters’ bags on that marsh was checked for several weeks in 1946 and 1947, tables 47 and 48. There was a re- duction in the number of juveniles per adult from the third week to the fourth IttiNo1s NATURAL History SurvEY BULLETIN Vol. 27, Art. Gam week in September, 1946, followed by a ) gradual increase in the number of juve- niles per adult until the first week in No- vember, when a very sharp decrease took place. There was a marked decrease in the number of juveniles per adult in the pe- riod October 20-25, 1947. When the Table 47—Number of juveniles per adult among mallards checked in hunters’ bags on the Delta Marsh, Manitoba, in each of 6 — weeks in the autumn of 1946. Numser | PerCent| JUvE- Periop oF Ducks| Juve- NILES CHECKED NILES Per ADULT September 3rd week. . 707 67 2.03 4th week. . 146 49 0.96 October Ist week... 329 54 1 2nd week. . 231 61 1.37 3rd week. . 196 63 1.70 November Ist week... 33 15 0.18 Table 48.—Number of juveniles per adult © among mallards checked in hunters’ bags on the Delta Marsh, Manitoba, in each of three — periods in the autumn of 1947. Numer | Per Cent| JUvE- PerRIoD or Ducks| Juve- NILES CHECKED NILES Per ADULT OetsiO 35: 121 72 25% Ocer 13-18 2). 174 71 2.45 Ovt; 20-25... 163 51 1.04 changes in these age ratios were tested sta- tistically, it was found that in both years the changes were significant at the 99 per — cent level (1946, X?=55.04, 5 d.f.; 1947, 2=19.34, 2 d.f.). a | ~*~ com A late hatch. sometimes as a result off es delay in initial nesting and sometimes as _ a result of severe losses of early nests, may delay the appearance of juvenile mallards — in Illinois, as in 1939, 1943, 1945, 1947, 1949, and 1950, fig. 12. The effect of am late hatch may be shown in the degree — of retention of juvenile plumage by young — during the southward migration, as was — evident in juvenile mallards in Illinois in ~ 1950 and 1953. Breeding grounds surveys indicated a delayed or extended hatch in 1950 (Hawkins 1950:42 ; Sowls 1950:— August, 1961 CUMULATIVE PER CENT 1942 1943 0 1939 1940 1941 BELLROSE et al.: SEX RATIOS AND AGE RaTIos 1944 441 1945 1946 1947 1948 1949 1950 Fig. 12.—Year-to-year variations in the seasonal migration of juvenile mallards through the Illinois River valley, 1939-1950, as shown by the proportion of each year’s juvenile flight that was in the valley in each of 6 weeks in autumn. 60) and in 1953 (Lynch & Gollop 1954: 47; Gollop 1954:67; Hawkins 1954:77). That the age composition of the mal- lard population in Illinois varied from week to week in the fall is shown by checks of hunters’ bags, table 44. In any one year, pronounced week-to-week vari- ations in the age composition of mallards taken by hunters in Illinois suggest that there may be many migratory movements, some scarcely detectable, within a local population. The adult-juvenile composition of the mallard flight in Illinois for the period 1939-1949 is reflected in fig. 13. Gen- erally, juveniles made up a greater part of the mallard bag early in the season than later. The juvenile proportion in hunters’ bags soon declined, as indicated by data collected during the first half of Novem- ber; it recovered somewhat during the second half of November but declined again during the first 2 weeks of Decem- ber. The decline in December resulted as juveniles moved farther south and large numbers of adults moved into Illinois from the north. In 6 of 7 years, juvenile mallards in Arkansas formed a greater proportion of the hunters’ bags in the second than in the first of two periods during which data were collected, table 49. The findings shown in fig. 13 and tables 49 and 50 suggest that, between the mid-flyway areas (Illinois) and the wintering grounds (Arkansas), juveniles may be more prone to leisurely migration than adults. The daily change in age composition of the mallard bag at Stuttgart, Arkansas, for December 2-11, 1950, is given in ta- ble 50. A marked change in the relative number of juveniles in the bag occurred on December 8. A large southward flight of mallards from Illinois on December 7, as a result of zero weather and snow, con- tained a relatively large number of juve- 100 ke z uJ oO x WW ra 15-31 I-15 16-30 I=15 OCTOBER NOVEMBER DECEMBER Fig. 13.—Juvenile-adult composition of the autumn flight of mallards in Illinois, as indi- cated by checks of hunters’ bags in the autumns of 1939-1949, 442 Ittinois NaturAL History Survey BULLETIN Vol. 27, Art. 6 Table 49.—Number of juveniles per adult among mallards checked in hunters’ bags at j ; Stuttgart, Arkansas, in 12 hunting seasons. | NuMBER PERIOD OF HunTING SEASON Siena | (enn: 1946-25. 8a ey Bee Nov. 23-26 1,889 Nov. 27- 1,461 Dec. 1 LOS fete caper Dec. 8-11 2,064 Dec. 12-14 L250 1948 rs ee ee Nov. 26-31 2,035 Dec. 2-4 965 If be Iara ee a are Nov. 18-21 1,830 Dec. 26-27 274 TOS Os eer Shs ee Dec. 2-11 Sele Dec. 28-29 149 LOS seamen Nov. 22-23 500 Deco 1-3 2,500 EOSD Foe cera Oe See Dec. 6-9 997 LOS SoM ee, Lee aoe Nov. 27-28 341 Dec. 21-22 230 1954-554 Ree Jan. 4-5 408 1955-56. . Jan. 7-8 458 LOS 8 )isce cee ee Dec. 8-10 L139 LOS Oras nt E Nov. 30- 1,053 Dec. 1 nile ducks. Its impact on age ratios in Arkansas seemed apparent. When age ra- tios before and after the influx of the juvenile mallards from Illinois into Ar- kansas were statistically compared, the difference was found to be significant (X?=45.6, 1 d.f.) at the 99 per cent level. Because Utah is a breeding ground for several species of ducks, an important molting area for several species, and an important migration area for many spe- cies, it might be anticipated that age ra- tios in this state would show a complex relationship to migration. Records on ducks taken in traps at Og- den Bay, Utah (Fuller & Low 1951 :42), indicated that “the earlier arrivals were immature birds, adults showing up more frequently from the last of August, .. .” This evidence from trapping operations late in summer plus declining numbers of juvenile pintails during the fall in the bags of Utah hunters, fig. 14, suggest the possibility of a pronounced movement of juvenile pintails through Utah before the hunting season. According to J. B. Gollop of the Canadian Wildlife Service (per- sonal communication), there was good PROBABILITY Per Cent Juvenices | THatT CHANGE JuvENILES Per ADuLT RESULTED : From CHance ~ ae) 1.22 <0.05>0.025 52 1.08 4 59 1.44 <0.005 67 2.03 68 oa) <0.10>0.05 71 2.45 -* 47 0.89 <0.05>0.10 51 1.04 1 42 0.72 <0.50>0.25 46 0.85 a 59 1.44 <0.05>0.025 a8 64 1.78 ee 65 1.86 1.0, 2) 43 0.74 <0.50>0.25 48 0.92 49 0.96. |. .5:.s.0—n 58 1.38. - |v.. 0 os 32 0.47 as 23 0.29 |... evidence in Saskatchewan in 1952 that a — mass exodus of juvenile pintails occurred — during late August. ee: A tally of adult and juvenile ducks that — were victims of botulism during August and the first half of September, 1952, on the Bear River Migratory Bird Refuge, table 46, also provides data on the age Table 50.—Number of juveniles per adult among mallards checked in hunters’ bags at Stuttgart, Arkansas, in each of 10 days in De- cember, 1950. % Numper | Per Cent| JUvE- DaTE or Ducks| Juve- | NILES CHECKED NILES PER ADULT Degie 2:2 535 39.6 0.66 ce 771 soso 0.64 ae 584 38.2 0.62 Ee 345 J35 0.50 Ges 59 32.2 0.48 fee 100 38.0 0.61 ae 240 58.3 1.41 Lt 372 46.5 0.87 £0 469 48.0 0.92 11 237 47.3 0.893 Dec, 2=11 5 ....\ 735712 42.0 0.72 % August, 1961 ratios of ducks in a Utah area before the hunting season. These data, unlike the data from ducks trapped at Ogden Bay, do not show a large juvenile duck popu- lation prior to the hunting season. Per- haps adults are more susceptible to botu- lism than juveniles, or perhaps there were differences in age composition between the duck populations on these two marshes, which are about 25 miles apart. Such dif- ferences were reflected in hunters’ bags checked on the two marshes, tables 55, 56, and 57. Further study of the composition of Utah duck populations seems very de- sirable, because of the differences in age ratios and the importance of seasonal in- fluences on age ratios in that state. Mallard migration in Utah in six au- tumns of the 1940’s, fig. 14, was some- what similar to that in Illinois, fig. 13. Juveniles were most abundant early in the BELLROSE et al.: SEX RATIOS AND AGE Ratios 443 season; their proportion in the bag stead- ily decreased to the November 16-30 pe- riod, after which it remained fairly con- stant. In Utah, the age pattern of mi- grating pintails tended to reflect that of migrating mallards, fig. 14. The green- winged teal showed a rather steady de- crease in the relative number of juveniles as the season progressed, while the shov- eler had a ratio of adults to juveniles that remained about the same throughout the season. Thus, in the selection of strategic sites for collecting age data on ducks, and in the evaluation of age ratios, migration schedules of waterfowl must be consid- ered. In some species, much of the migra- tion occurs outside of the hunting season; in such species, age ratios calculated from data collected from hunters’ bags may not be representative of the populations. Un- | 100 e. 100 mo 75 75} : = | WwW W . S 50 © 50 jeg a lJ W a a 25 25 fe) fe) 100 100 75 75 5 = W WJ Oo 505 © 50 jaa a a a 25 25 fe) ) 5-31 I-15 16-30 I-15 —s: 15-31 I-15 16-30 I-15 OCTOBER NOVEMBER DECEMBER OCTOBER NOVEMBER DECEMBER Fig. 14.—Juvenile-adult composition of the autumn flights of mallards, green-winged teals, pintails, and shovelers in Utah, as indicated by checks of hunters’ bags in the autumns of 1943, 1944, and 1946-1949, 444 less traps are operated effectively through- out the period of migration, they, too, will provide biased data. Age ratios obtained from mallards while on their wintering grounds undoubtedly are relatively unbiased by seasonal move- ments. It should not be assumed that a similar statement would be true for all species. For example, in the pintail, birds of the two sexes and ages tend to flock sep- arately in winter, and shifting of these flocks along the Texas coast is common. Regional Variations in Age Ratios Regional variations in the age ratios of ducks first became apparent to the writers when data on the ducks checked in hunt- ers’ bags in Utah, Texas, and Illinois dur- ing the fall of 1943 were compared. Since that time, data which provide for further evaluation of regional differences in age ratios have become available, tables 51-57. Mallards.—The juvenile percentage in mallards checked in hunters’ bags in I~ttinois NaTturRAL History SurveEY BULLETIN Vol. 27, Art. 6 each of eight areas of the Mississippi Fly- way is shown in fig. 15. Juveniles made up a large proportion of the ducks that were taken in Manitoba because the adult drakes tend to migrate from there early, and the juveniles are more vulnerable to shooting early in the hunting season than at any other time. It is not known why the juvenile proportion of the mallards taken by hunters in Ohio (the marshes at Sandusky Bay) was so much greater than that taken by hunters in Michigan (the Pointe Mouillee Marsh, which is less than 50 miles from Sandusky Bay). The progressive north to south de- crease in the juvenile proportion of the mallard population, as shown by checks of hunters’ bags in Manitoba, the Upper Mississippi areas, the Illinois River valley areas, and the Arkansas areas, table 51 and fig. 15, reflects both a progressive decline in the juvenile population and a decline in vulnerability to hunting as a consequence of increasing wariness among juveniles. \] <2] S ” e “4 <2] e sretetetes: 8 ie) eeectctcte: C529 S509 rere 0% q oe ' 4% POOOY Oeeetetete: POOVDO>D seteterere. 7 5 DOV q , q 4 Cx] a4 OOOO" Statatetet Cerereren Seroreene ; ‘eres, 5 eetetete verererert 70 Peo S55 SSS] SSG PIO ca Wocereren 2) ‘eereere, PSSA esheets: Ww Socestetee steseenns SoG Severerers P ; Wecereren 06,0,0.6, RS OOOO = stetotote! ME Sstatotets eeetetet S Seeatetete Soverecene Weeseeeee Sosestetes eeveteten SG KX PSS 4 KX = wesecerene sestetetet Oecteteee! S55 “4 Orererenee 2 ost Bel ERS eee rv wecerenene etetetete: , srerenenen eototetee sereterek - 4 vetererece eeeetetet, , Sed vetenecere, 2 <2 Sd srerereren 4 4 eerarene, Petaratens erererene erereren Ww Socoseneet veterarens erereren O { og 04 wrerereen aces Weeetetete anecereee: Ped Weeeiehete = vasererere, ‘ 4 4 iereeces: veceeeeeee, — er 60 Oo OO \n | enn C559 5524 Pd WwW 25 eetetetet OOO RLF Weeeeeeetek Reseeeeeee d erereree Mereteres ererecee anenereee eeneeee a 24 “ Seterorece erececeee, erereren Revererens 4 % 24 evecare ereceren eetetetel, RM } ; Severerece eereeeee, S05 Roverereee LS Ye E5525 x54 GE E5505 pS SRG erenenee Meceetetc’ ‘ 24 KS 6 BS] verececere, wereteten Rocerenene LS 3 KS XI B59 voceees Seteteters Roreenese % 34 "6 24 PoC << esetatee, etetatee, PS “4 1 ; 5505 52585 RG os > W x4 K, 4 RRR restetgtets ea bee, CS on KO cd ¥ 52505 CJ ©, °° xX ROM BS Rx ROX ‘ 5 5 ¢€ d LX % rs oS rx OY rs 4 % ; ‘araRes Sy Xt e b> J wm “4 6e, J 2 “4 &, Ye 24 ¢ © xX Ww 82 on “4 D 4 ‘on os Ke ren > a om “4 DS J OZXxK % “4 S CJ % 1% S re ¥ % re 5 rs ® 4 ~~ Se, < e od “e. o Q “4 ? ees q 5 = BY odie mS MS 2 2 <4 > x rS2 os KO od Ls b> ., of S > — Ke Oe XY Rs “ “ i So Od i IS S Re Ro RRR xx a 50 ROO RLS POO OOOF 0000.04 We1e:6.8: Fig. 15.—Juvenile percentage in mallards checked in hunters’ bags in each of eight areas of the Mississippi Flyway, 1946-1949. August, 1961 One question of concern to students of age ratios is: “Can age ratios at any one place be used to indicate yearly changes in production?” ‘Table 51 and fig. 16 show the yearly trends in the juvenile propor- tion of the mallard population in a num- ber of areas. Bag checks in Manitoba are in general agreement with those in the Mississippi River basin areas in showing increases in the juvenile component in Table 51.—Number of juveniles per adult regions of North America, 1946-1949. BELLROSE et al.: SEX RaTIos AND AGE RATIOS 445 1947 and 1948 and a decrease in 1949. Year-to-year differences in the time of de- parture of adults and juveniles from the breeding grounds probably explain some of the differences between mallard age ra- tios taken in Manitoba and those taken in the Mississippi River basin areas. Year-to-year changes in the juvenile proportion of the mallard populations of the Great Lakes areas—principally the among mallards checked in hunters’ bags in 13 1946 1947 1948 1949 1946-1949 REGION wud os ud os uu os POV ac) os wus os 224] 5< |e24| $< [e24)| = |E2| s= leee| = 5 CO} eH |g eo) ee |S eC) ee |g Ol ee |g le asst FROME (230 lee, (260) oe las ee ta soles Messe Manitoba. «.+...<\onies-4-<+ 0 (1 Va ep lee 1,537] 8.80] 2,569] 10.63 Netley, Manitoba..........|......|...... 903) 4.17| 1,248| 5.71] 893] 2.92| 33044} 4.29 Welta, Manitoba........... 1,874| 1.46 496} 1.70 DE e cota eee es ale = eee 2,621) 1.62 Upper Mississippi River. ... A929 653) 2272 eleO2 S200 2351) 5 O593)e2)570 |p 2elS WISCONSIN coc. cece s cauenws 333) 3.44 287 3295 AO SoG Wot ile ey) Si, Mell] S's IMENT SAM ee ips oe crsiecrece oes « STAN) OXSS 212| 1.08 Ble Les PROM ists) ifs 1 500) OUNIGig Aceh ae 993| 4.84 940} 3.22 819} 6.04 735| 2.62) 3,487); 3.90 Micltan ae Thal scene cis terele ate etckee sd kee 369) 0.86 GIT LS L046 e077, Illinois River valley........ Me SPAY GPS) S14) 2-36) 15215) 38 SOTO. 97)\ 3 943\ ele IMIS SOE eke cei Sid oe adie ism des SLi ee 518} 1.76 408} 2.92) 1,094) 1.04) 2,347) 1.48 ANAK RCIG Sie Bi o5.0 lel lS Oo l/ | eel OS! So O00ls 2.22/02, LOL On Siilie/ 7il|iealeAs eee Sb RS, 2,514} 1.88] 1,749] 1.81| 1,252] 0.99] 57515] 1.60 "hohe Gee 853| 1.16] 2,067| 0.66| 1,216] 0.74] 1,062] 0.88] 5,198] 0.78 Table 52.—Number of juveniles per adult among mallards checked in hunters’ bags in Manitoba, Illinois, and Arkansas, 1946-1955 and 1959. NuMBER OF JUVENILES PER ADULT anne cow eee YEAR ee Manitoba eee ee Arkansas Manitoba Illinois and (Delta) Valley) (Stuttgart) and Illinois Arkansas | A sa 1.46 1.25 Tele 0.21 0.09 Meee sees. s cis x2 1.70 2.36 1.63 0.66* 0.73 DES eo aera ye S218 Qe22 1.94 0.96 “iD Sige eae |e eee ee 0597 O2OL. ~*~ eneee. eee 0.06 Re Prarie ess sis swiss > = A WETS oh MISS seed 0.80 7S GG Ete eee yt Lise ee ahah sate car cit tae 0.00* EMT iA tcp ais Bilictevaieaic ise siete ase 1.65 er Cope En cmtre ee reece ee 0.21* oF ooS DOE Gee eee 1.48 OT ee oy nea a ng oe 0.66 ere 1.62 0.91 1.04 0.71 L137 SPEAR a, = 5 icc hatet alles cis caidia sks» 1.78 Tyee 10 ga leek eS eer oa 0.38 ee erika 2 isc'k el = 0.78 0.34 0.29 0.44 0.05 BNDTATEIES AAO OG OD 2.14f Hoop HO 25a 0.53 0.31 *Only in 1947 did Illinois exceed Manitoba in number of juveniles per adult; only in 1951, 1952, and 1954 did Illinois fail to exceed Arkansas in number of juveniles per adult. +For years in which data were available for both Manitoba and Illinois. tFor years in which data were available for both Illinois and Arkansas. 446 Horicon Marsh in Wisconsin, the Pointe Mouillee Marsh in Michigan, the marshes at Sandusky Bay in Ohio—show little cor- relation with changes in the Mississippi River basin areas, fig. 16. However, the Great Lakes areas are frequented by only a small proportion of the mallard popula- tion of the Mississippi Flyway ; these areas are to the east of the principal routes used by mallards migrating between their breeding and wintering areas. There was reasonably close agreement in the year-to-year fluctuations in the num- ber of juvenile mallards per adult in hunt- ers’ bags in the Mississippi River basin areas: the Upper Mississippi River, the Illinois River valley, and the Stuttgart, Arkansas, area, table 51 and fig. 16. There was a highly significant relationship be- tween the age ratios of mallards bagged in the Upper Mississippi River area, Illinois River valley, Missouri, and Arkansas dur- ing the period 1946-1949, table 51, as demonstrated by a correlation coefficient of r=+0.969 or higher, which indicated that the probability that the correlation was due to chance was less than 0.01. The age ratios for mallards bagged in the Illinois River valley were close to those for mallards taken in the Stuttgart, 100 90 80 we) Fr 860 =50 MISSISSIPPI BASIN AREAS ~ ~ =_ + 80 =< >~ Ohio ~ 6 70 “LWisconsin x 6O ss Michigan <3, WwW Bl a 1946 1947 1948 1949 I_ttinois NATURAL History SURVEY BULLETIN 1950 Vol. 27, Art. 6 Arkansas, area in all but 2 (1950 and 1953) of 11 years (1946-1955 and 1959), table 52 and fig. 16. The lack of agree- ment in the age ratios from the two areas in 1950 and 1953 is believed to have been related to a delayed hatch on the breeding grounds followed by a somewhat delayed movement of juveniles to Illinois, where a high kill of these young birds occurred. In 1950, mild weather induced large numbers of mallards to remain on the breeding grounds until November 7, when a severe cold front resulted in an unusu- ally large exodus. The ducks moved rap- idly down the flyway, and the adults passed through Illinois without stopping so long as is customary. Because of the unusually rapid movement from the breed- ing grounds to the heavily shot mid-flyway areas, juvenile mallards had not been much exposed to hunting by the time they arrived in Illinois and, thus, were more vulnerable to hunting than in most other years. Fluoroscopy of live-trapped ducks in 1953, in revealing an unusually low per- centage of juveniles with shot wounds, in- dicated that the young of that year, like those of 1950, had not been much exposed to hunting before their arrival in Illinois. MANITOBA MARSH AREAS Ao ee Arkansas I i sa GREAT LAKES BASIN AREAS 1955 1954 1951 952 I953 Fig. 16.—Year-to-year changes in the juvenile percentage in mallards checked in hunters’ bags in each of several areas of North America, 1946-1955. ON August, 1961 BELLROSE et al.: SEX RATIOS AND AGE RaTIOS 447 Table 53.—Number of juveniles per adult in five species of ducks checked in hunters’ bags in seven regions of North America, 1948. Brack Duck PINTAIL BALDPATE REDHEAD LESSER ScaupP REcIon ges | 87s ao} aa 0 | as malas ars SO|/mo| eo|seg| oe / 4g) sg / ss oo | =a = acs 2 > 5 z ZO Nee eo eee | bene | ete pee | alee _ LERRODE A 8 Sela 5 re ire eae 145 | 4.88 S13) ley) 388 |24.00 275 Oe 59 SGC A 208 | 3.35 248 | 4.66 547 |10.11 DAD AGE 296 Daly SUNG ETO SNe ee 374 | 1.08 102 | 0.96 191 | 3.00 £5) | 5 740) ele, 3.76 aN Da, 4 6 ye 419 | 3.54 258 | 6.14 DDI AD Gi ea a ne eae “GIN so oes eee SMe Titles Meola ton elle he Sola See ete We. Pe Celie le MERE & Illinois River valley........ SS paleo efile) Om (Nese) Sunless cee cc | (cae elle eye saed| ae we |W “GLB. ood 65 pete es eee ee ee PINKY || WaT) ine | Oss) DOGASE7 Oo Ie ese tee The lack of hunting experience by juve- niles before reaching Illinois in 1950 and 1953, plus the abnormally rapid flight of adults through Illinois in 1950, resulted in the unusually large differences between Illinois and Arkansas in the number of juveniles per adult in the mallard bag in those years, table 52. With infrequent exceptions, such as those in 1950 and 1953, it appears that age ratios taken along the main stem of the Mississippi Flyway from Delta, Mani- toba, to Stuttgart, Arkansas, provide an index to the yearly productivity of the mallard in the flyway. Other Species.— Considerable _ re- gional variation in the number of juveniles per adult was found in 1948 for each of five species of ducks checked in hunters’ bags in Manitoba, states of the Mississippi Flyway, and Utah, table 53. Two of the four species checked in Manitoba had more juveniles per adult in that province than in other localities. Regional variations in age ratios among the several species and within any given Table 54.—Number of juveniles per adult among mallards checked in hunters’ bags in two regions of the Illinois River valley, 1939. Numser | Per Cent Juve- REGION or Ducks| Juve- NEES CHECKED NILES PER ADULT Wpper..... 1,203 60.4 a2 Lower 1,058 od 1.36 species probably result in part from differ- ences in seasonal movements among the species and between juveniles and adults. It is assumed that regional variations in age ratios derived from inspection of hunt- ers’ bags would be most pronounced in those species of ducks that depart from the breeding grounds early in the migration season. Because the hunting seasons for the various states do not coincide and be- cause the migration schedules of adults and juveniles of a given species may differ, adults of a species may receive greater hunting pressure in one state, juveniles in another. In an unpublished report for 1954, Milton W. Weller, then of the Univer- sity of Missouri, pointed out the diverse movements of the two redhead age classes in Manitoba. Many adult redheads moved northward to molting areas following the breeding season, while most juveniles re- mained on breeding areas. “he redhead bag in the molting areas showed a low juvenile percentage, whereas the bag in the breeding areas showed a high juvenile per- centage. Weller speculated that differ- ences in the migration schedules of adults and juveniles might influence bag data all along the migration routes. The juvenile component in the popula- tion of each duck species investigated has tended to be so low in Utah, tables 53 and 55, as to warrant special attention. The marshes around Great Salt Lake have long been the scene of unusually heavy concentrations of early-migrating water- fowl. As census records showed, peaks in 448 waterfowl populations at the Bear River Migratory Bird Refuge in 1946, 1947, and 1948 occurred before the season opened (Van Den Akker & Wilson 1951: 373). Because juveniles in hunters’ bags decreased proportionately as the hunting season progressed, fig. 14, the possibility is raised that flights which are top-heavy in juveniles may leave Utah before the hunting season opens. If this assumption is substantiated in subsequent investiga- tions, it would partially account for the I_ttino1is NaturAL History SurvEY BULLETIN Vol. 27, Art. 6 abnormally large number of adults in the bags of Utah hunters. No doubt some differences between the age ratios representing various bag inspec- tion stations have resulted from differ- ences in the character and size of areas — sampled. In some cases, age ratio data representing a checking station may be from only a single, relatively small area, such as the Delta Marsh or Netley Marsh in Manitoba. In other cases, the data may be from many marshes representing many Table 55.—Number of juveniles per adult in five species of ducks checked in hunters’ bags in two areas adjacent to the Great Salt Lake, Utah, in 1947. NumsBer or Ducks CHECKED SPECIES ins Ogden Farmington Bay Bay Mallardey acc an:- 677 373 Gadwall. took bs 398 276 Baldpate:230.5.0225¢ 422 276 Pintalicy ass 1,374 1,281 Green-winged teal. . TBH 446 Shoveler;....... 0: 419 357 Juvenites Per Aputt PROBABILITY _ THAT Ogden Farmington pt Due au pe Bay CHANCE 0.68 1.01 <0.005 2.36 0.85 <0.0005 3.70 1.76 <0.0005 DS 0.75 <0.0005 1.62 2.09 <0.025 2.19 3.01 <0.005 <3" Table 56—Number of juveniles per adult in six species of ducks checked in hunters’ bags in two areas adjacent to the Great Salt Lake, Utah, in 1948. NuMBER OF Ducks CHECKED SPECIES Ogden Farmington Bay Bay Mallard: einen. 817 247 Gadwallccaa.-7 429 205 Baldpate 3 whee is 1,142 320 Pinta geen aoe 2,210 761 Green-winged teal... 1,069 395 Shaveler5s once es 687 386 JuvenrtLes Per ADULT ProsABilree THAT Ogden Farmington ss i Bo, Bay Bay CHANCE 0.88 0.77 <0.20>0.10 1.01 1.20 <0.40>0.30 2.30 2.44 <0.90>0.80 0.78 0.64 <0.0005 0.88 0.78 <0.30>0.20 2.06 1.96 <0.80>0.70 Table 57.—Number of juveniles per adult in six species of ducks checked in hunters’ bags in two areas adjacent to the Great Salt Lake, Utah, in 1949. NumBer Or Ducks CHECKED Juvenites Per ADULT PRoBaBILITY | ; Sad = THaT SPECIES Ogden Farmington Ogden Farmington ce a a Bay Bay Bay Bay Crane Wallendsedenan Pee 541 380 0.66 0.87 <0.05 ae Gadwalli ck occ 1,153 322 0.48 0.85 <0.0005 Baldpate. 3). ..4:73- 296 334 3.00 0.90 <0.0005, Bintatlieasmeen cn 3: 2,027 871 0.51 0.54 <0.50>0.40 Green-winged teal. . 13.212 567 0.52 0.77 <0.0005 _ Shoveler’y cima se 555: 614 1.04 1312 <0.60>0.5 oy 4 August, 1961 acres. For example, mallards checked at Stuttgart, Arkansas, were shot on at least 20 different swamp or reservoir tracts scat- tered over an area having a 25-mile radius. Most of the mallards checked in the IIli- nois River valley were bagged at 10 clubs distributed over a linear distance of 100 miles. Only a slight difference in the number of juvenile mallards per adult between populations of the upper and lower sec- tions of the Illinois River valley was found in 1939, table 54. This difference was not significant at the 90 per cent level mae — 1.79) 1 d.f.). Much greater differences in number of juveniles per adult for several species of ducks were found between populations of two marshes 25 miles apart and adjacent to the Great Salt Lake, Utah, in 1947- 1949, tables 55-57. The probability that the differences were the result of chance is shown in tables 55-57. There was a sta- tistically significant difference between age ratios in the two areas in 11 of 18 meLESLS. JUVENILES PER ADULT ‘These data suggest that the age compo- sition of migrating flocks differs and that fortuitous circumstances result in flocks especially numerous in birds of one age 1939 = 194 1943 1945 1947 BELLROSE et al.: SEX Ratios AND AGE RATIOS 449 class or the other in a particular marsh. Where only one waterfowl area in a re- gion has been sampled, as Winous Point in Ohio or Pointe Mouillee in Michigan, the age ratios derived may or may not reflect those for the entire region. For species other than the mallard, re- gional data are not adequate to permit evaluation of the age ratios derived in any one area. For each of these species, we have compiled data from as many areas as possible in the Mississippi Flyway on the assumption that data for the total flyway represent the species better than the data from any one area and reflect year-to-year changes in the age composition of the pop- ulation. Factors Affecting Age Ratios Age ratios can be used for appraising the productivity of ducks if the data on which they are based have been carefully evaluated as to the effect of seasonal, re- gional, and shooting biases. Sufficient data for calculating age ratios corrected for differences between juveniles and adults in vulnerability to hunting have been ac- cumulated for the mallard in the Missis- sippi Flyway, table 58 and fig 17. Most of the data used in the table and graph Uncorrected Data Corrected Dota 1949 = 1951 1953 1955 1957 1959 Fig. 17.—Uncorrected and corrected numbers of juvenile mallards per adult in bags of | Mississippi Flyway hunters in each of several years; uncorrected numbers, 1939-1959; corrected | numbers, which compensate for differences in hunting vulnerability between adults and juveniles, | 1939-1955. Points on the graph for 1939-1955 are based principally on Illinois data, table 58. | Points for 1956-1959 are based on data from Missouri, table 59. Because data for 1955 showed the number of juveniles per adult among Illinois mallards (1.78) to be about 10 per cent less than the number among Missouri mallards (1.99), the point for each year in the period 1956—- | 1959 represents a figure that is 10 per cent less than the corresponding figure in table 59. Vol. 27, Art. 6) ILtinois NaturAL History SurvEY BULLETIN 450 --—- a PERALTA IE Aes ES EER #200°C toz°2 POE 10°T 80°C cO°T 90°F 8° Che 81°F L9°F -0°T cer S¥°C 68°C Crt COT 6¢°1 60°F Ovg NI Nay Linay wag SATINZANL 40 YdaWAN dd.Loawuory “6 2Ge1 Woy sesh JaYIG YsOUI JOJ sone ‘[ Gp ase “ul syoNp ay ‘stoulf[] Woy sivak JayIO JO¥ sy[Npe pue sayiueanf jo ssequnu meee +~ a S ac SET FAS ObL ‘tb +x6Z°0 44FOOT 60€ ‘ET Reh Oia Swe ex Ske wee too°0 ter'L ae? bj.e tee liat/s. win) w le, i8) eet aire 56 Prd BLT 897 OL 65°0 16°0 OFT L6 $9°0 78°0 LeI¢ TI 9L°0 59° 95h SII 6ST re ZOE 876 LS°0 €L°0 Lez ‘Z 86 0L°0 16°0 CO FII $9°1 gI°¢e 167 8L os*I 9¢°7 THT 877 08°0 Coa 985 6LE tr'0 84°0 6FI ‘I ZI€ LL°0 611 166 LSI 97'T $6°1 €8t OLT 6L°0 BIT 678 169 69°0 10'T OGL G O19 L5°0 trl ILP ‘1 LIC OFT SP $76 ovg NI Oovg NI ovg NI Lindy wd L1naqy wd ovg NI SNI}H{ L1aay SATINGAN [ SATINGAN [ sLTAGYy 10 WAGWAN 10 WadWAN 10 YAHWAN 10 WaGWAN daLoauUoy dd LOauAOoNs) | “S[ENPIAIpU Jo sJequinu [JO] UO paseq 9BPIBAY x,y “aaoge soinsy AjieaA jo aseivayyt d uo peuredxe ¢o6] pue QS6] 4O0f¥ Aqypiqrseuyna ayrueanf 0} ajnpe jo ones ‘g¢ ayqea ul papny> ‘6h 21983 Url papnpul syxoNp oy ‘sesueyIW Woy FSH, pu OSG] 10¥ si[npe pue sayiueanf jo syequnn i : “[Sp e3ed uo pauredxe se ‘ysnojg stuuIgoyy wo1j ejep uo paseq oneYy, —_— _ 9D COO st HH OOM Re HH OME HY STAM MMNEHENMNAANDAANMYM * . * oo ee Fed C6 8 . SO eae ie ee ee aR NOILV1Nd0g NI SaTINGAN[ iO wadWAN daLOayUuosd (SauvUq) ONILNOY OL ALITIGVYUINTO A a1INaAN[ OL LINGY dO O1LLVY ovg NI SATINGAND[ JO wdG@WAN “*saupak "* aSD4IaY I S°:°:=iNVNVeNw0tw“a=aoajxw@w—wwswwqworea=«onaOa > a] 0.6 0.6 0.8 1.0 1.2 1.4 JUVENILES ability of juveniles. For the period 1939-— 1955, the corrected figure was 0.95 juve- nile per adult and 2.7 juveniles per adult hen. These figures probably reflect the age composition of mallard populations in the Illinois River valley for the 17-year period quite well, for inaccuracies in the yearly vulnerability rates would tend to cancel each other out over the period. Trends in the age composition of mal- lard populations in the Illinois River valley reflect trends in the age composi- tion of mallard populations on the breed- ing grounds prior to the hunting season. However, population figures obtained in Illinois do not represent the true age composition of the populations on the breeding grounds, because of the compara- tively greater loss from hunting experi- enced by the juvenile segment of the I~tinois NaturAL History Survey BULLETIN PER ADULT ON BREEDING GROUNDS Fig. 18.—Numbers of juvenile mallards per adult on the breeding grounds just prior to the hunting season, as calculated from numbers of juveniles per adult in Illinois during the huntin C4 season; each of the Illinois numbers on which curves A, B, and C are based has been adjusted to compensate for a greater shooting loss among juveniles than among adults before reaching Illinois: 4, 2.0 juveniles per adult, B, 2.5 juveniles per adult, and, C, 3.0 juveniles per adult. Vol. 27, Art. 6 population between the breeding grounds and Illinois. Both shrinkage in the juvenile segment of mallard populations and seasonal de- clines in the vulnerability rates of the juveniles are indicated by the progressive- ly smaller relative numbers of juveniles in hunters’ bags as the ducks moved down the flyway from Manitoba to Illinois to 1.6 1.8 2.0 28 ay Arkansas, table 52. Juvenile mallards are undoubtedly more vulnerable to hunters in Manitoba than to hunters in Illinois, and to hunters in Illinois than to hunters in Arkansas, as shown by seasonal changes in vulnerability ratios, table 44. Shrinkage in the juvenile segment 0 mallard populations between the breeding grounds and Illinois is indicated not only by data in table 52 but by rather abstruse calculations employing band _ recoveries, mortality rates, and juvenile vulnerability rates, as discussed below. An average annual mortality rate for adult drake mallards in the Mississippi Flyway of about 40 per cent has been derived from band recovery data for drake mallards banded as adults at Lake Chautauqua, Mason County, Illinois, 1939-1944 (Bellrose & Chase 1950 9). August, 1961 It seems reasonable to assume that hunt- ing accounts for about three-fourths of this average annual mortality and other causes for one-fourth, or an average an- nual mortality rate of 30 per cent from hunting and 10 per cent from other causes. An analysis of 6,000 indirect (after the year of banding) recoveries of adult drake mallards banded at Lake Chautauqua dis- closed that 47.6 per cent or about one-half of the recoveries were from points north of the Illinois River valley. It seems reasonable to assume further that hunting results in approximately a 15 per cent reduction in the numbers of adult mal- lards before they reach the Illinois River valley from the breeding grounds. Data in tables 44 and 47 suggest that the juveniles are 2 to 3 times as vulner- able as adults during the early fall season when in migration from Manitoba _ to Illinois. If we assume that juveniles are 2.5 times as vulnerable as adults, and that hunting takes a toll of 15 of each 100 adults before the flights reach Illinois, then we may say that hunting takes a toll of 2.5 times as many juveniles or 37.5 of each 100 juveniles in the same period. Fig. 18 shows a scale for converting the age ratios of mallards occurring in wild populations in the Illinois River valley to age ratios which would be com- parable for wild populations on the breed- ing grounds prior to the hunting season. Following is an example showing the method used to determine a point on the scale, fig. 18, representing the probable number of juveniles per adult on the Canadian breeding grounds when 0.6 juvenile per adult has been determined to exist in mallard populations in Illinois; the adults are assumed to have been sub- jected en route to Illinois to a shooting loss of 15 per 100 and the juveniles to a shooting loss of 37.5 per 100. When A = the number of adults on the breed- ing grounds per adult in Illinois, with a presumed 1:0.6 ratio of adults to juveniles in Illinois, a =the number of adults to 0.6 juve- nile in I]linois, p =the per cent of the adult popula- tion remaining after a 15 per cent loss en route to I[Ilinois, BELLROSE et al.: SEX Ratios AND AGE RATIOS 453 then eee SP Ale 1 o OE85 the number of adults on the breed- ing grounds to | adult in Illinois. When Y =the number of juveniles per adult on the breeding grounds, with a presumed 1:0.6 ratio of adults to juveniles in Illinois, y =the number of juveniles to 1 adult in I1linois, p =the per cent of the juvenile popu- lation remaining after a 37.5 per cent loss en route to Illinois, then Ses 0.6 p 0.625 the number of juveniles on the breeding grounds to 0.6 juvenile in Illinois. Y= = 0.96, Thus, when there is a ratio of 0.6 juve- nile per adult in Illinois, the adults have been subjected to a 15 per cent loss en route to Illinois, and the juveniles have been subjected to a shooting loss 2.5 times as great as that of adults, the ratio on the breeding grounds is 0.96 young to 1.18 adult, or 0.81 juvenile to 1 adult. An average of 0.95 juvenile per adult was calculated for mallard populations in the Mississippi Flyway, principally Illi- nois, over a 17-year period, 1939-1955, table 58. This average takes into account differences in vulnerability between adults and juveniles. If juveniles suffered a loss of 37.5 per cent en route, the calculated average number of juveniles on the breed- ing grounds just prior to migration per 0.95 juvenile arriving in Illinois was 1.52 (0.950.625). If adults suffered a loss of 15 per cent en route, the calculated average number of adults on the breeding grounds just prior to migration per adult arriving in Illinois was 1.18 (1.00.85). For the 17-year period, the calculated average number of juveniles per adult on the breeding grounds just prior to migra- tion was 1.29 (1.52~1.18). If the average number of juveniles per adult in Illinois (0.95) is to the number of juveniles per hen in Illinois (2.7), table 58, as the number of juveniles per adult on the breeding grounds (1.29) is 454 ILLINOIS NATURAL History SURVEY BULLETIN Vol. 27, Art. 6 Table 59.—Number of juveniles per adult among mallards shot at the Duck Creek Wildlife Area, Puxico, Missouri, 1955—1959.* NuMBER OF YEAR Ducks CHECKED 19S Se ioks Ration hone EG ate 5,581 LOS Gack ek eee ee 2,368 NOS No acierete es eae ona toate 478 LOSS. ee a ee vos 581 TSG, hen ea) lie ae 2,064 APPROXIMATE Per Cent JUVENILES 95 Per Cenr JUVENILES Per ADULT CoNFIDENCE Limits 66.6 1.99 1.79-2.19 58.5 1.41 1.37-1.45 54.8 12k 0.87-1.55 aes 0.60 0.47-0.73 32.6 0.48 0.42-0.54 *Data supplied by George Brakhage of the Missouri Conservation Commission. to the number of juveniles per hen on the breeding grounds (X), the number of young per hen on the breeding grounds can be calculated by solving for X in the following equation: 0.95 :2.7::1.29:X 2 i Bag data for the Mississippi Flyway, principally Illinois, uncorrected for the greater vulnerability of juveniles to hunt- ers, showed an average of 1.43 juveniles per adult over the period 1939-1955, table 58. This average is greater than the calculated average number of juvenile mallards per adult on the _ breeding grounds just prior to the hunting seasons (1.29). A higher figure for Illinois than for the breeding grounds may have re- sulted because the disproportionate loss of juveniles before the mallard popula- tions reached I]linois was more than com- pensated for by the disproportionate vul- nerability of juveniles in Illinois. Age Ratios as Measures of Production Many wildlife technicians have assumed that increases in the number of juvenile ducks per adult in hunters’ bags reflect increases in production of young during the breeding season immediately preceding, that age ratios can be used as indices of production, and that curves plotted from age ratios may be regarded as production curves. Year-to-year changes in the age ratios of mallards in the Mississippi Flyway are shown in tables 52, 58, and 59 and fig. 17 for 21 years, 1939-1959. The produc- tion curve plotted from the corrected age data follows a pattern somewhat similar to that plotted from the uncorrected age — data, fig. 17. However, because errors of — varying magnitude are probably present in the yearly vulnerability factors used in — correcting age data, it has been deemed © advisable to use uncorrected age data rather than the corrected data as the better indices of year-to-year changes in pro- ductivity. F The data (uncorrected) on which the — broken line in fig. 17 is based indicate that lows occurred in the production of young mallards in 1941, 1945, 1950, 1953, — and 1959; highs occurred in 1939, 1943, 1948, 1951, and 1955. This somewhat rhythmic production trend may be an — inherent characteristic of waterfowl popu- lations and may prove to be density de-— pendent in origin. ; Significant data for the Mississippi Fly- — way are lacking on yearly changes in pro- duction of species other than the mallard. However, John E. Chattin of the U. 5. Fish and Wildlife Service has made avail- — able age ratios of pintails trapped at seven — banding stations in California, Oregon, and Nevada from 1949 through 1959. The relatively large number of juveniles — among the pintails trapped, particularly in 1951 and 1952, fig. 19, suggests bias in the — samples, possibly the result of juveniles entering the traps more readily than adults. Nevertheless, the variations in trap — selectivity from year to year are probably not great enough to produce large errors in the indices of production. It is believed that the age ratios obtained from pintails trapped in the Pacific Flyway probably provide a fairly reliable picture of the production trend of the species. A com- parison of mallard age ratios in the Mis- sissippi Flyway with pintail age ratios in August, 1961 the Pacific Flyway for 11 years, 1949- 1959, fig. 19, reveals for most years an unexpectedly close agreement between the production trends of the two species. The extent of agreement in production trends between the two species is especially remarkable when differences in distribu- tion and habits of the species are con- sidered. The pintails of the Pacific Fly- way breed largely in the western part of the northern plains, whereas the mal- lards of the Mississippi Flyway breed largely in the eastern part of the northern plains. Moreover, mallards are more prone to nest in the Aspen Parklands and the northern mixed Coniferous Forest than are pintails, which are for the most part confined to the grasslands. Factors responsible for the yearly fluc- tuations in mallard production appear to have fairly consistent simultaneous effects on pintail production. Discovery of this fact justifies the use of Mississippi Fly- way mallard age ratios as criteria for eval- uating the accuracy of breeding ground surveys and the effect of environmental conditions on over-all duck production. Because breeding grounds surveys have been used in the past to provide most of the waterfowl production information on which annual hunting regulations have been based, and will undoubtedly be used for a similar purpose in the future, an appraisal should be made of the validity of these surveys. Breeding grounds surveys are affected by the vastness of the breeding grounds, shifts in waterfowl populations with changing water conditions, and difficulty in finding and counting broods. Age ratios obtained from ducks bagged on and south of the breeding grounds provide a means for evaluating the validity of waterfowl breeding grounds surveys and in them- selves serve as measures of production. We have attempted to appraise the validity of breeding grounds surveys by comparing the results of surveys on the plains of Manitoba and Saskatchewan with the mallard age ratios obtained through inspection of hunters’ bags in the Mississippi Flyway, principally Illinois. Banding of ducks on the breeding grounds has demonstrated that most of the Missis- sipp! Flyway ducks breed in Manitoba and Saskatchewan. BELLROSE et al.: SEX RATIOS AND AGE RATIOS 455 The first comprehensive breeding grounds surveys were made by the U. S. Fish and Wildlife Service in 1947. In that year, although the nesting population was reported “fair” for Saskatchewan as a whole, brood production was not corres- pondingly high (Lynch 1948 :33). In the same year, the duck crop in the pothole country of Manitoba was considered good, but the production in other types of nest- ing area was “moderate to very poor” JUVENILES PER ADULT 1949 1951 1953 1955 i957 1959 Fig. 19.—Year-to-year changes in the num- bers of juveniles per adult in two species, the data derived by two methods in two areas: pintails trapped in the Pacific Flyway and mallards checked in hunters’ bags in the Mis- sissippi Flyway, 1949-1959. (Hawkins 1948:52). Yet, in 1947, mal- lard age ratios from the Mississippi Fly- way showed a pronounced increase in juveniles over the number in 1946, fig. 17. A year later, 1948, “good production” was reported, and “moderate improvement in the waterfowl output for Manitoba” was forecast, by Hawkins & Cooch (1948: 97); a small increase in the duck popula- tion of Saskatchewan was recorded by Soper (1948:63). Mallard age ratios ob- tained in the Mississippi Flyway in 1948 showed a further increase in the number of juveniles per adult to a new peak, hig. 17. In 1949, mallard age ratios from the Mississippi Flyway indicated that a sharp drop had occurred in the relative number of young, fig. 17. From the breeding grounds, Hawkins (1949:64) reported that, in Manitoba, nest success was well below that of 1948. Lynch (1949:52) re- ported a reduced nesting population in Saskatchewan as a whole, but a successful 456 hatch in the Aspen Parklands, where mal- lards from the drought-stricken south- western part of the province had moved to join the ducks that normally nest in the Parklands. In 1950, Mississippi Flyway age ratios disclosed a further drop in the number of young mallards per adult, fig. 17. On the breeding grounds, Hawkins (1950:45) concluded “that Manitoba produced con- siderably fewer ducks in 1950 than in 1949.” In Saskatchewan, Colls (1950 :40) reported “evidence of a lack of, or an un- successful attempt at, first nesting among mallards and pintails,”’ and added that by the end of July there appeared to be no important attempts at second nesting by these two species. In 1951, mallard age ratios derived from bagged ducks in the flyway indicated a marked increase in the production of young, fig. 17. Hawkins, Gollop, & Wel- lein (1951:49), reporting on other species as well as the mallard in Manitoba, wrote, “the juvenile crop probably doubled the previous year’s.” Colls & Lynch (1951: 40), after observing the success of the first nesting attempt in Saskatchewan, wrote that ‘a more than usually success- ful waterfowl-rearing season” was antici- pated for the area. In 1952, the flyway age ratios indicated a decline in the number of young mallards per adult. From one Canadian province, Hawkins & Wellein (1952:64) reported: “Manitoba’s contribution to the fall flight of 1952 should be about one-fifth less than in 1951.” From Saskatchewan, Gollop, Lynch, & Hyska (1952:37), following a survey in July, 1952, reported a potential production ‘almost twice that of last year.” A decrease in the production of young in 1953 was reflected by age ratios for mallards bagged in the Mississippi Fly- way and by field observations in the area. Moderate decreases were reported in Manitoba by Hawkins (1954:76) and in > pace by Lynch & Gollop (1954: 49). Age ratios for mallards bagged in the Mississippi Flyway showed little change from 1953 to 1954, fig. 17. For 1954 on the breeding grounds, predictions made after a summer census were that the fall flight of ducks from southern Manitoba ILLINoIs NATURAL History SurvEY BULLETIN Vol. 27, Art. 6 would be “about the same as last year,’ but that a “noticeable” reduction would occur in size of flights from northern — Manitoba and from both northern and southern Saskatchewan (Crissey 1954:59, 62.37). In 1952, John J. Lynch of the U. S. Fish and Wildlife mathematical formulas charts 1 and 2). From the formulas he 1959 1949 =I951 1953 1955 1957 Fig. 20.—Relationship between age ratios of mallards in autumn and the hatch on the breed- _ ing grounds in the previous spring, as indi- cated by number of juvenile mallards per adult in hunters’ bags in the Mississippi Flyway, principally Illinois, 1949-1959, and forecast indices of duck production in Canada (Lynch forecast indices, Gollop, Lynch, & Hyska 1952: _ 37), the indices derived from breeding grounds — surveys in Manitoba, 1953-1959, and Saskatche- wan, 1951-1959. derived forecast indices, one as of June 1 and another as of August 1. The August index was based upon July data: number of broods per square mile, number (per square mile) of late-nesting pairs and single drakes and hens which supposedly represented late-nesting pairs, number of ponds per square mile, number of duck- — lings per class III (almost completely feathered) brood, and number of class II (partially feathered) and class III broods — per square mile. An index rating of 100 was deemed satisfactory; an index rating — of 300 was deemed perfect. Later, some — minor modifications were made in the — formulas. A mimeographed report, “Waterfowl Breeding Ground Survey Report, 1958,” — compiled by Arthur S. Hawkins for the — U. S. Fish and Wildlife Service, provides — a comparison of late season forecast in- dices for Saskatchewan, 1951-1958, and for Manitoba, 1953-1958. A similar re- Service developed — for forecasting — waterfowl production in Saskatchewan — (Gollop, Lynch, & Hyska 1952:37 and — — 250 INDEX, 2.035 = SASKATCHEWAN 5] \ 2 = 4 & 200 1.5 x x< a a ” z 150 Ow = = PS Zz re) \ w = 100 INDEX, \ 052 | a MANITOBA 5 , > = August, 1961 MILLIONS a SOUTHERN 1953 1954 1955 BELLROSE et al.: SEX RATIOS AND AGE Ratios 1956 457 SASKATCHEWAN S57 1958 1959 Fig. 21.—Estimated numbers of mallards in various parts of the Canadian breeding grounds in May, 1953-1959. port compiled by Hawkins in 1959 pro- vides data on breeding grounds forecasts for that year. The production forecast indices for Saskatchewan and Manitoba may be compared with the number of juvenile mallards per adult as checked in the bags of Mississippi Flyway hunters, fig. 20. For the period 1952-1959, the popula- tion curve plotted from the forecast in- dices of waterfowl production in Saskatch- ewan was similar to the curve plotted from the Mississippi Flyway age ratios for mallards, fig. 20. However, for the years 1955 through 1958, and especially for 1958, the forecast indices showed con- siderably higher production than was shown by the age ratios, fig. 20. Manitoba forecast indices showed very little correlation with mallard age ratios from the Mississippi Flyway, fig. 20. For example, in 1957 and 1958, Manitoba forecast indices pointed to an increasing production of young; yet the mallard age ratios from the Mississippi Flyway pointed to a decreasing production of young. That there is only slight correlation may be ascribed to Manitoba’s relatively small contribution of mallards to Illinois and adjoining states. Aerial surveys made on the breeding grounds in May indicate that about six times as many mallards nest in the plains and parklands of southern Saskatchewan as in the plains and park- lands of southern Manitoba, fig. 21; the Saskatchewan contribution to the Missis- sippi Flyway kill is larger than that of Manitoba, even though much larger num- bers of Saskatchewan mallards than of Manitoba mallards are killed in the Central and Pacific flyways (Cartwright 1956:14—5, 17—8, 20-1). For 8 years, beginning with 1952, Saskatchewan breeding grounds indices showed production trends similar to those derived from mallards shot by hunters in the Mississippi Flyway, fig. 20. Informa- tion on breeding grounds success of ducks in Saskatchewan in 1951 was somewhat contradictory. The report by Colls & Lynch (1951:40) indicated “a more than usually successful waterfowl-rearing sea- son.” The forecast index for 1951, al- though above 100 and therefore “‘satis- factory,” indicated a production that was low compared to that of most other years of the period 1949-1959. We are in- clined to believe that some mechanical error was made in calculating the 1951 forecast index for Saskatchewan. During the period 1949-1954, duck production as determined from breeding grounds surveys in Manitoba showed a fairly close relationship to production as 458 determined from age ratios of mallards shot in the Mississippi Flyway, principally Illinois. However, production as deter- mined by the forecast index in Manitoba showed no positive correlation with pro- duction as indicated by age ratios of ducks shot in the Mississippi Flyway; dia- metrically opposite production trends were indicated for 1954, 1955, 1957, and 1958, fig. 20. The mallard flight reaching IIli- nois from Manitoba, compared to that from Saskatchewan, may have been so small as to have had little influence on age ratio figures obtained from mallards in- spected in hunters’ bags in the Missis- sippi Flyway. One item apparently responsible for bias in the forecast index, especially in Mani- toba, has been the production factor asso- ciated with late-nesting ducks. This factor was included in the index formula to measure the anticipated brood production represented by pairs, lone hens, and lone drakes (believed to be mates of incubating hens) found on the last survey flights, usually conducted in mid-July. The pro- duction from ducks that are actually breeders may be lower than anticipated, and many ducks that are classed as breeders may be through breeding. Charles D. Evans of the U. S. Fish and Wildlife Service and Ralph Hancox of the Mani- toba Game Branch recognized the latter possibility in Manitoba in 1958 (unpub- lished report), when they found abnormal- ly high numbers of molters and premolters on breeding areas. In spite of diligent effort to classify breeders and nonbreeders correctly, Evans and Hancox believed that they included many nonbreeders in their late-nesting index. It is apparent from age ratio data from the Mississippi Flyway that in those years in which there was a major population shift from the Canadian Grasslands north to the lakes and marshes of the Aspen Parklands and Mixed Coniferous Forest production of young declined more than had been anticipated. No doubt some of the differences be- tween production data based on age ratios obtained from bagged ducks in the Missis- sippi Flyway and similar data based on breeding grounds surveys stem from dif- ferences in production between the Grass- lands, the Parklands, and the Coniferous ILttinois NATURAL History SurvEY BULLETIN Vol. 27, Art. 6 Forest region. Because of difficulty of ac- cess, difficulty in making observations, and a low density of breeding ducks, only cursory duck surveys have been made in the Coniferous Forest region. Hence, the production of mallards from this region: is largely unknown but may be larger than suspected. Although the population density of mallards there may be low, this region is so vast that it may well con- tain a sizable breeding population. Other differences between production data from the Mississippi Flyway and data from the breeding grounds surveys may result because the Mississippi Flywa data include only mallards, whereas data from breeding grounds surveys include all species of ducks. Mallards usually make up over half of the breeding popula- tion, but diving ducks and _ late-nesting eae such as the baldpate and the gad- wall, which may show yearly production trends different from those of the mallard may influence the production data from the breeding grounds. Production and Environment It is difficult to evaluate the effect of environment on waterfowl production be- cause of the vastness of the breeding grounds and the variations in water and weather conditions. Seldom, if ever, are water or weather coudinose similar over the entire breeding range. Moreover, an area that is favorable for waterfowl in one year may be unfavorable the next. Nevertheless, a general review of water and weather conditions in Manitoba and Saskatchewan, the principal breeding range of the mallard of the Mississippi Flyway, has been made for the years 1939- 1946 from The Duckological, a news sheet published at irregular intervals by Ducks Unlimited (Canada), with headquarters at Winnipeg, and for the years 1947-1959 from published and unpublished reports of breeding grounds surveys by the U. 5. Fish and Wildlife Service and the Canad- ian Wildlife Service. In the following paragraphs the water and weather condi- tions on the breeding grounds for each of the 21 years in the period 1939-1959 are summarized in relation to mallard pro- duction as indicated by the number (un- corrected) of juveniles per adult inspected in hunters’ bags in the Mississippi Flyway August, 1961 —lIllinois and Arkansas, table 58, and Missouri, table 59. Water conditions on the Canadian plains in the spring of 1939 were much improved over those of 1938. Conditions for breeding ducks were good in Sas- katchewan and poor in Manitoba. Most water areas persisted until broods were on the wing. These conditions resulted in a production per breeding mallard (uncor- rected number of juveniles per adult) which was about equal to the average of such production data for 17 years, 1939- 1955, table 58. In 1940, spring water conditions in Manitoba were the worst in the history of that province and in Saskatchewan were poor as far west as the central part. Water conditions were good in western Sas- katchewan. Good rains in June improved many water areas. Mallard production in this year, as in 1939, was close to the average for the 17-year period, table 58. In the spring of 1941, water conditions, although greatly improved over conditions in 1940, were considered fair in Manitoba and ranged from poor to good in Sas- -katchewan. Water areas rapidly dried up when such summer rains as fell failed 'to maintain them. Heavy losses among ducklings occurred as a result of drought. : A drop in the number of young per adult : bagged in the Mississippi Flyway re- vealed a sizable decline in mallard produc- tion, table 58. In the spring of 1942, water conditions | were fair to good in Manitoba; they were bad, fair, or good, depending on the locality, in that part of Saskatchewan where most of the ducks are produced. Heavy spring rains prevailed over most of the plains, and these continued into the summer. The number of young per adult in the Mississippi Flyway, table 58, indicated a moderate increase in mallard production. Spring water conditions in 1943 throughout the Canadian plains were the best in many years, being rated fair over northern Saskatchewan and_ northern Manitoba and good to excellent almost everywhere in the southern parts of these provinces. In that year, age ratios in the Mississippi Flyway, table 58, indicated a pronounced increase in mallard pro- duction. BELLROSE et al.: SEX Ratios AND AGE RATIOS 459 In 1944, there was “lots of water” in northern Saskatchewan and Manitoba, but in the southern parts of these provinces, where most of the ducks are produced, water levels were largely “dangerously low” to fair. A larger than usual propor- tion of the breeding waterfowl population moved through the Grasslands northward into the Aspen Parklands and Mixed Coniferous Forest. Rains in June re- moved danger of heavy loss of ducklings through drought. Mallard production de- clined markedly to a point below average, table 58. In 1945, spring water conditions were good in Manitoba and all of Saskatchewan but the southwestern part, where few Mississippi Flyway mallards breed. Water conditions in Manitoba remained good for ducks, but southern prairies of Saskatche- wan dried up. Subnormal temperatures occurred through much of April and May, and, in the northern portions of Manitoba and Saskatchewan, ice was still present on marshes and lakes on May 24. Age ratios of ducks bagged on the flyway indicated that mallard production had declined to the lowest point since the study started in 1939, table 58. In 1946, water conditions were excel- lent in Manitoba and through a belt 100 miles wide in eastern Saskatchewan. June rains improved water conditions in Al- berta and Saskatchewan. May was ex- cessively cold, and heavy frosts occurred. Age ratios from the Mississippi Flyway indicated that mallard production rose considerably but remained below the 17- year average, table 58. More detailed information on breeding grounds conditions became available in 1947, when extensive surveys were in- augurated by the U. S. Fish and Wildlife Service. Salient facts from these surveys have been condensed in tables 60 and 61 and are shown graphically in figs. 22 and 23. ‘These tables and figures, as well as tables 58 and 59, should be referred to in connection with the following paragraphs on duck production and breeding grounds conditions. In 1947, a year in which fair to good water conditions prevailed and slight to moderate water loss occurred during the breeding season in Manitoba and Saskatch- ewan, the number of juveniles per adult Vol. 27, Art. ILttinois NaTurRAL History SurvEY BULLETIN 460 : ($561) door) 2 youdyT “(gg6T) SWIEITTIAA (7561) B¥S4H 2Q ‘youd’y ‘dojjor (1S61) YousTT 2g sT[OD (161) YUdT 2% SIIOD “(OS6T) SID (1561) YUAT 29 STD “(6F61) YOULT (1S61) YUd'T 29 SI[OD (861) Jado te pls a (8$61) YBIWS “(g$61) YouAT NOILV1NdOd ONIGAIUNG ANV SNOLLIGNO’) TIVLNAWNOUIANST YOd ALTYOHLAY ,LINay wag SATINAAN[ GuvT1VI] 40 wadWAN a[qusoavy yewuouqns IYSYS é [eUIon, IYBIS é [ewIon qyst[s yewsouqns a[qQusoARy A[PW9IIXY WYBIS asiaApe A394 Jeuou sa0qy WYBIS yary 5! jewsouqns -9} BIOPOY] ISIOAPY jewaouqns 9} BIDPOT] SALLIALLOY AUYALVAId WAT Sso’'T ONINAV I ONTAdS WALV MA al auUuvaosg AIg sx0nq T1y 40 NOILV1Nd0g ONTIaaIAg ua] [=9xXq Pee peas 2 Ud][POXY 100g poor) poor) SNOLLIGNOD WALV AA uvaT ‘ABMALT IddIssissiyA] 9Y} UI S$eq Sid}UNY UI payooY9 I[Npe sod sazrucanf{ jo Jequinu Aq pazeorpul se uononpoid psejjew pue ‘eog[—/p6] ‘UBMOYOJeYSeG UJOYINOS UI spuNOs’$ ZuIpeasq UO suOT}IPUOD [eJUeWMIUOITAUY— [9 2[GUL “$9°7S6I URIPM ¥ SUIYMEPT ar e798) ul uMOYS Ie *pepnpul JO9sueI} [euonIppe euo wos BJep YIM ‘tS6l pue [Sé6I 4} soindy :(,SatJy aenbg jo sequinyn,, aq A[peiqnopun pynoys AT eqe} ul , “1A “bg Jed ‘on,,) sepium aienbs ¢y/*¢¢] jo vaie s0y “O/: PSG] SUIyMETT ‘AT ayqe} ul ejep wo; pajepnopeas "gg 9]qe] wWoly LIE, NPSOL) SUPE rT “(ES6T) SUTBTTTTM (FS61) SUbyMeyy “(ZS61) VPP 29 SULyMLHY : (S61) SUyMeHy (TS61) UPTPM 2g “dojjoy ‘surymepyy (OS61) SULyME EY (OS61 “6F61) SUPYMUEY (OS61) SUlLyME FY “(8h61) YO00D 2 suLyMryy (OS61 ‘8F61) SULYMEL NOILV1Nd0d ONIGIIUG ANV SNOILLIGNOZ) ‘IVLNAWNOUIAN WOd ALIMOHLAY c8°0 ie E Look €L°0 L6°0 9 9f°C ,xLTNGY wag SATINGAN [ auv11VJy dO WadWAN, jew4ouqns aqvsoavy AJaW9.43XY auoN, asIOAPY [eultou sA0qy ysiy aSIOAPY [eurIoNy ysiy jewouqns a[qusoary AJOWAIXY WYSYS aSIIAPY jewiou aA0qy a} vIBpoPy a]qvioary ]ewuouqns YSIS ISvIDAY Jeurouqns ISIS SALLIALLOY AMNLVUIdNA [, sso'y ONINAV I ONIYdS WALV AA Tes tS78c Lo° IF SLE CCE rel 8°IT aly AUVNAOS AIg sxonqd 11y 40 NOILVTNdOg ONIGIIUG poos 03 Wey 100g qe y WuaT]eoxy] poos) pees) Tey SNOLLIGNOD WALV AA een 741 *"ABMA,T Iddississif] 9Y4} UI s$eq SsazUNY UI paxooY9 3[Npe sod sazrueAnt jo Jaquinu Aq pazeorpur se uononposd psejjew pue ‘gog[—sp6[ ‘BqojIUBFA UJOYINOS UT spuNOIs SuIpseslq UO sUOT}IPUOD [eJUaWUOIIAU—~9 21GB], August, 1961 in the bags of Illinois hunters revealed a spectacular rise in production by the mal- lard ; the rise occurred even though spring temperatures were below normal. ‘The spectacular increase in production con- tinued in 1948, as water conditions in Canada improved. In 1949, water condi- tions in Saskatchewan were poor, and mallard production dropped drastically. In 1950, water conditions were excel- lent in both Manitoba and Saskatchewan. May of 1950, however, was unusually cold and wet. Mallard production, as in- dicated by age ratios of ducks bagged in the Mississippi Flyway, declined. In 1951, water conditions were good through the breeding season in Saskatchewan and fair in Manitoba; a major water loss oc- curred in Manitoba. In that year, mallard production increased considerably. The two provinces differed materially in water conditions in 1952. In Manitoba, rapid disappearance of water areas began in April and continued through the summer; by August waterfowl conditions were the worst known since breeding grounds ob- 40 32 WwW = = SASKATCHEWAN WwW PONDS < 524 oS wn joa WwW a wo = 16 {e) a > c= 4 = @ 10) 1948 1949 1950 1951 1952 1953 MALLARD BELLROSE et al.: SEX Ratios AND AGE Ratios 461 servations were started. In Saskatchewan, water conditions were favorable through- out the breeding season. Mallard produc- tion in 1952 declined very little, if at all, age ratios of bagged ducks indicated. In 1953, water conditions were excellent in Saskatchewan and fair to good in Mani- toba. There was no water loss during the season in Manitoba and only a slight loss in Saskatchewan. Despite these favorable water conditions, age ratios of bagged ducks revealed a decline in the production of mallards in 1953. Although small water areas in Sas- katchewan and Manitoba were almost at maximum numbers in 1954, age ratios indicated only a slight increase in mallard production, fig. 22. In 1955, with a further increase in number of ponds in Saskatchewan, but with a sizable decrease in the number in Manitoba, mallard pro- duction increased materially. Ponds were down in number in Sas- katchewan in 1956, but they increased in number in Manitoba, fig. 22. In that year, age ratios of bagged ducks indicated a ,. _ MANITOBA ‘\ x PONDS MALLARD JUVENILES PER ADULT : JUVENILES ie} 1954 1955 1956 1957 1958 1959 Fig. 22.—Relationship between water conditions on the Canadian breeding grounds and mallard production, as indicated by the number of ponds per square mile in southern Saskatche- wan and southern Manitoba in May of certain years, and by the number of juveniles per adult checked in hunters’ bags in the Mississippi Flyway. Points on the graph representing number of juveniles per adult for 1948-1955 are based principally on data from Illinois, table 58; points for 1956-1959 are based on data from Missouri, table 59. Because data for 1955 showed the number of juveniles per adult among Illinois mallards to be about 10 per cent less than the num- ber among Missouri mallards, each point on the graph for the years 1956-1959 represents a figure that is 10 per cent less than the corresponding figure in table 59. Data for the breeding grounds are from the U. S. Fish and Wildlife Service and the Canadian Wildlife Service. 462 drop in mallard production. In 1957, ponds were down in number in both provinces, and mallard production de- clined. In the following year, 1958, water areas continued down in number in Mani- toba but increased in Saskatchewan; mal- lard production showed a further decline. In 1959, water conditions in Manitoba remained about the same as the year be- fore, but the number of ponds in Saskatch- ewan declined sharply. For the fourth consecutive year mallard production de- 25 2.0 JUVENILE MALLARDS PER ADULT PONDS PER MALLARD AND ie} 1952 1953 1954 Fig. 23.—Relationship between the density of the adult mallard population on the Canadian — ILttinois NATURAL History SurvEY BULLETIN 1955 Vol. 27, Art. 6% mile in May) followed similar trends in most years of the period 1948-1959, fig. 22. Mallard production and water abun- dance followed divergent trends in 1950, 1953, and 1958. In 1954, mallard pro- duction showed no decisive trend, while water abundance rose markedly. In — Manitoba, mallard production tended to — parallel water abundance in the years % 1956-1959 but not in the 3 years previous. _ In 1945, 1950, and 1953, when water conditions on the breeding grounds were ee ee a ne JUVENILES 1959 1957 1956 1958 breeding grounds in spring and the production of young, 1952-1959, as indicated by the number — of ponds per mallard in southern Manitoba and southern Saskatchewan in May and by the num-— ber of juveniles per adult checked in hunters’ bags in the Mississippi Flyway the autumn fol- — lowing. Data for the breeding grounds in 1952 represent Saskatchewan only. Points on the graph representing number of juveniles per adult for 1952-1955 are based principally on data — from Illinois, table 58; points for 1956-1959 are based on data from Missouri, table 59, as ex- — plained in the legend for fig. 22. Data for the breeding grounds are from the U. S. Fish and © Wildlife Service and the Canadian Wildlife Service. ¥ clined; the number of juveniles per adult in the Mississippi Flyway, as represented by data from Missouri, was at a 21-year low, tables 58 and 59. No completely objective correlation can be made between waterfowl production and conditions on the breeding grounds. Much of the information from the breed- ing grounds is not of an objective nature; it is not subject to convenient or exact measurement, and the effects of the many environmental variables are not well un- derstood. In Saskatchewan, mallard production (as determined by the number of juve- niles per adult among birds bagged in Illinois) and water abundance (as meas- ured by the number of ponds per square fair to excellent and mallard production was down, temperatures below normal and ~ other unseasonable weather conditions, in- cluding blizzards, occurred as late as mid- May, disrupting the nesting activities of the mallard, pintail, and other early nesters. In 1947, when water conditions — were fair to good, and subnormal temper- atures were experienced early in the nest-— ing period, mallard age ratios indicated substantially better than average produc- tion. Concerning weather and water condi- tions in Manitoba in 1950, Hawkins (1950:42) reported as follows: If abundant water were the only require- ment of nesting waterfowl, ducks nesting in Manitoba would have had a “banner” year; August, 1961 they did not, however, in spite of the greatest spread of surface water in many years. Sub-normal temperatures continued through- out the nesting and brooding season. May was particularly cold and wet, possibly a factor in the poor hatch. From July 12 to 15, when many broods were only a few days old, temperatures dipped almost to the freezing point, perhaps another factor affecting success. Colls (1950:36-7) reported that un- seasonably cold weather prevailed all over Saskatchewan for most of the summer and that the more northerly lake country re- mained ice-bound in some cases as late as the end of May; however, he stated ‘“‘that weather and water conditions over south- ern Saskatchewan were exceptionally favourable for the 1950 waterfowl popula- tion.” Hawkins (1954:75) reported that on April 15, 1953, the worst spring blizzard in many years combined with several days of freezing temperatures to adversely af- fect waterfowl production in Manitoba. Another record-breaking blizzard oc- curred on May 11, and smaller snow- storms on April 24 and May 14 resulted in snowdrifts which could have buried large numbers of nests. Indeed, a few nests that had been buried were found after the snow disappeared. Furthermore, temperatures accompanying the blizzards were sufficiently low to freeze unprotected eggs. In Saskatchewan, Lynch & Gollop (1954:45) reported that May, 1953, was very cold, with much snow prior to the middle of the month. Stoudt & Buller (1954:55) reported that the weather was “wet, cold and miserable for the most part’ during the nesting and brooding season, but concluded: “We have always heard of the dire effects of wet, cold weather on newly hatched ducklings but such ill effects were not noted during the 1953 brooding season.” A late breakup of ice occurred in Mani- toba lakes in 1954 (Evans 1955:72), with freezing temperatures and snow extending into early May. May and early June were generally cool and wet. Saskatchewan experienced a_ record- breaking cold wave in late April and early May of 1954 that substantially de- layed nesting by mallards and pintails (Gollop & Lynch 1955:46-7). As late BELLROSE ef al.: SEx Ratios AND AGE Ratios 463 as mid-May, many lakes were still frozen over. As a result of adverse weather in the spring of 1954, Stoudt & Stinnett (1955: 60) found an extremely high nest loss among mallards as well as other ducks on a small study area in southeastern Saskatchewan. They attributed the loss in the first nesting effort of mallards to a blizzard and zero temperature on May 1. Most of May and June was charac- terized by cold, very wet weather, retard- ing the development of good nesting cover. The paucity of nest cover and the lack of stable food for predators resulted in great- ly increased predation upon duck nests. Flooding destroyed many nests missed by predators. Decreased production by the mallard on the plains of Canada in years of very plentiful water and of cold weather, snow, and heavy rains at nesting time suggests that cold and excessively wet springs may be as unfavorable to duck production as dry and warm springs. It is quite evident that water and weather conditions on the breeding grounds during the nesting and rearing period were major factors contributing to the gross changes in mallard production in 1939-1959. Yet there was another factor in mallard production, population density, that seems to have operated in most years within the broad limits of the environment, and, indeed, that may well have been the dominant regulating factor in production in those few years in which there was a poor correlation between en- vironment and age ratios. In 2 years having similar water conditions but breed- ing populations of different sizes, the num- ber of juveniles produced per breeder may be lower in the year with the larger popu- lation than in the year with the smaller. Several years ago, an inverse relation- ship between population density and pro- duction of young was reported for the muskrat by Errington (1943:877), who stated: “the data indicate that rates of increase tend to vary with particular habitats and inversely with the density of the breeding stock.” That an inverse relationship between population density and production could be detected in upland game was noted by several writers (Baskett 1947: 25-7; 464 Bump ef al. 1947:540; Errington 1945: 13). Production in the mallard and possibly other duck species may bear, within cer- tain undetermined limits, an inverse rela- tionship to population densities, or a direct relationship to number of ponds per duck. (Increased density in a duck population on the breeding grounds may be brought about by a decrease in the number of water areas as well as by an increase in the number of ducks.) With the exception of 1953 and 1954, years in which cold temperatures and snow reduced production of the mallard, there was a good correlation between number of ponds per breeding mallard and produc- tion of young on the Canadian breeding grounds. As the number of ponds per breeding mallard decreased from 2.0 to 0.6 in the Grasslands and Aspen Parklands of Manitoba and Saskatchewan, produc- tion declined from 1.78 juveniles to 0.54 juvenile per adult, fig. 23. A change in the density of the mallard population on the breeding grounds may affect production in two ways: (1) alter the rate of nest destruction and desertion; (2) alter the relative number of ducks that can be accommodated by prime breed- ing habitat. Sowls (1955:74) found that most mal- lards nest within 100 yards of pond, slough, or lake margins rather than at greater distances from water. The area of nest concentration adjacent to a body of water has been called the nesting zone. As ponds and other small water areas decline in number, greater concentrations of mallard nests occur in the nesting zones of the bodies of water that remain. It is probable that, as nest density increases, the rate of nest loss rises. Although data on the relationship between nest density and nest loss are lacking for waterfowl, Stokes (1954:36) found that in pheasants nest abandonment increased with breeding density. Unpublished field studies by Alex Dzubin (letter March 5, 1960) of the Canadian Wildlife Service suggest that space requirement also may be related to mallard production. Dzubin believes that, through interactions involving both ag- gressive and sexual behavior, pairs of mal- lards space themselves over the breeding ILttinois NATuRAL History Survey BULLETIN Vol. 27, Art. 6 grounds. Adequate spacing is most evi- dent in the Aspen Parklands region, with its abundance of water areas; it is less evident in the Grasslands region, which may have a scarcity of water areas. Space behavior of ducks around waiting areas tends to place a limit on the number of pairs any one area can accommodate. The role of space in regulating the size of breeding populations of waterfowl is apparent in an analysis made by Schroeder (1959:4-5) of water areas and numbers of breeding ducks in North Dakota. Schroeder found that the numbers of breeding ducks and water areas tended to fluctuate up and down together. For example, in 1950, water areas numbered 11.4 and breeding ducks 24.6 per square mile, whereas, in 1959, water areas had declined to 2.1 per square mile and ducks to 8.4 per square mile. Evans & Black (1956:52) found a direct relationship between water areas and breeding ducks on an 11.25-square- mile prairie pothole area in South Dakota. Their study showed that as the number of potholes with water on May 10 in- creased and then decreased from 1950 through 1953 so did the number of breed- ing pairs of ducks. Stoudt (1959:103) reported a direct relationship “up to a certain point” be- tween numbers of breeding ducks and numbers of water areas on a study area 40 miles long and one-eighth mile wide near Redvers, in southeastern Saskatche- wan. He did not find this direct rela- tionship in “extremely wet years and extremely dry years.” From 1953 through 1958, there were only small variations in the number of water areas each year on May 1 in a Lousana, Alberta, study area, but the number of breeding pairs of mallards on this small area rose from 103 to 338 dur- ing that period (Smith 1959:3, 8). The number of ponds on May 1 decreased from 198 in 1958 to 131 in 1959 and the num- ber of breeding pairs from 338 to 241. The smaller a study area, the less likely it is to show direct relationships between — the numbers of breeding pairs and the numbers of water areas. Local variations — in mortality rates, homing, and population — saturation levels that grossly affect the — data for small areas may have no appreci- — August, 1961 able effect upon the data for extensive areas, because the many local variations in the extensive areas tend to cancel each other. Because the space behavior of ducks limits the number of breeding pairs that a given waterfowl habitat can accom- modate, when an increase occurs in the breeding population of an area that has reached the limit of its carrying capacity, or when a decrease occurs in the number of ponds on the area, some of the ducks associated with the area must do one of two things: (1) move to other areas not occupied to the saturation level or (2) fail to reproduce. The areas to which the ducks move may be of poorer quality for the production of young than the areas occupied to the saturation level. Biologists have long been aware of the tendency of bird populations to make maximum use of the best available habitat before occupying less favorable habitat. On a Saskatchewan study area, Stoudt (1952:55) found that breeding pairs of ducks tended to make maximum use of the small water areas (1 acre or less) and shift to less favorable habitat when the prime areas were occupied to the limit of their carrying capacity. Under conditions associated with popu- lation or habitat changes, ducks may move from a region of basically good habitat to a region of inferior habitat. In 1959, there was an increase in the number of mallards found during May in the marshes of the Coniferous Forest in northern Alberta and other northern parts of Canada and a decrease in the number found in southern Saskatchewan. The Coniferous Forest lacks the quality habitat for nesting mallards supplied primarily by the Grasslands and secondarily by the Aspen Parklands. Biologists have noted that under severe crowding many ducks do not breed and that some ducks that make attempts at nesting do not make further attempts if the first attempts fail. Arthur S. Hawkins and Gerald Paspichal in an unpublished report of the U. S. Fish and Wildlife Service on the 1959 breeding season in the pothole country of western Manitoba noted that many ducks in that area were individuals that had been displaced from other areas. They found indications that BELLROSE et al.: SEX Ratios AND AGE RaTIOs 465 some ducks did not attempt to nest and that others did not make the usual re- nesting attempts after having lost nests. Stoudt (1959:104) observed that many pairs of ducks in southeastern Saskatche- wan in 1959, a year of very low water levels, “did not seem to nest at all.” Fig. 17 may be interpreted as showing that when the Grasslands and Aspen Park- lands have reached the limit of their carry- ing capacity as a result of population in- creases and/or habitat deterioration, the production of juveniles per adult mallard declines for 2 to 4 years, until the breed- ing population has declined to a point where population density is no longer a limiting factor. Then, when a decrease in population or an increase in water areas results in more space per breeding pair, the production of young per breeder in- creases for 1 to 3 years, until population density again becomes a limiting factor. The highs and lows in a breeding popu- lation of mallards may lag 1 or 2 years behind the highs and lows in the produc- tion of young per breeder. The first year a high breeding population produces a smaller number of young per breeder, the over-all population will probably con- tinue to increase because of the large number of breeders still present to produce young. The over-all population may con- tinue to increase even into the second year of lower production. When the breeding population is at a low point, the over-all population will probably continue to de- cline for a year after an increase in pro- duction, as the increased number of young per breeder may fail to result in as many young as are needed to replace the ducks lost through hunting and natural mortal- ity the previous year. The foregoing analysis of the effect of environment on production of mallards and other ducks points up the importance of water areas that are available to breed- ing pairs. Also, it points to abnormally low temperatures and associated weather conditions in April and May as factors of major importance in production. Ab- normally low temperature conditions do not occur on the breeding grounds as frequently as abnormally low water condi- tions. Within the framework of accept- able nesting environment, and within certain undetermined population limits, 466 ILtinois NaturAL History SurRvVEY BULLETIN Vol. 27, Art. 6 Table 62.—Number of juveniles per adult hen (the number corrected for the greater vul- | NuMBER OF J Caspar? = 3 UVENILE UMBER OF sreciss | Nowmen or | Newnan or | Jovetiss | vivrenanni: | Juvemues sri oe iry Factror* Per ADULT EN Mallard jcc5..5 sina 3,631 19, 860 5.47 ree 4.2 Black duck.'....... 402 2,858 7g | 1.8 4.0 Gadwalls soso. 201 15335 6.64 2.4 2.8 Baldvates ix ase: cs 210 2,280 10.86 29 327 Pinte. issu ees 445 | 2,669 6.00 1.9 Ro Green-winged teal. . 226 | 1,427 6.31 1b 3.7 Blue-winged teal. . . 370 | 1,901 5.14 he 7 3.0 Shoveler:. 0. i .s..-: 119 836 / 7.03 1 Wears 4.1 Redhead.......... 190 1,882 9.91 325 2.8 Ring-necked duck. . 123 1,043 / 8.48 2.0 4.2 Canvasback....... 208 | 2,745 13.20 2.9 4.6 Lesser scaup....... 297 15525 5.14 2.0 2.6 *Correcting factors for most species are from tables 42, 43, and 45, ratio of adult to juvenile vulnerability. The correcting factor for the green-winged teal and the shoveler is assumed to be the same as that for the blue-winged teal, and the correcting factor for the ring-necked duck the same as that for the lesser scaup. production of mallards, and possibly all species of waterfowl, seems to be inversely related to population density. Production in Different Species Age ratios of ducks checked in hunters’ bags in the Mississippi Flyway for the period 1946-1949 provide indices of pro- duction for the various species, table 62. At least a partial correction for the greater vulnerability of juveniles than of adults has been made by using banding data from Illinois for the black duck and blue-winged teal, tables 42 and 43, and banding data from Canada for the mallard, gadwall, baldpate, pintail, redhead, canvasback, and lesser scaup, table 45. It has been assumed that the ratio of adult to juve- nile vulnerability in the green-winged teal and shoveler is similar to that in the blue- winged teal and that the ratio of adult to juvenile vulnerability in the ring- necked duck is similar to that in the lesser scaup. Even though the calculations repre- senting the “corrected number of juveniles per adult hen,” table 62, were derived from arbitrarily selected vulnerability ratios, it is believed that they are so close to the actual juveniles-per-hen figures that some useful generalizations can be made. The differences among the species are not so great in the “corrected number of juveniles per adult hen” asin the actual number of juveniles per adult hen in hunters’ bags, table 62. The vulnerability differential between adults and juveniles offers an explanation for the excessively high ratios of 10 to 13 juveniles per adult hen that have been found in checks of hunters’ bags. Several species of ducks appear to have about equally high production rates, table 62: mallard, black duck, shoveler, ring- necked duck, and canvasback. The bald- pate and green-winged teal seem to be intermediate in production. The gadwall, pintail, blue-winged teal, redhead, and lesser scaup appear to be species with comparatively low production rates. The fact of survival in a duck species indicates that the species is adapted to maintain its place in the total duck popu- lation. The production of each species must compensate for the losses suffered through mortality, or the species declines. With possibly a few exceptions, notably the redhead and the wood duck, no duck species has been known to undergo more than a temporary major decline in popula- ticn status in recent times. Age Ratios in Population Management One aim of waterfowl management is the establishment of hunting regulations that will permit the greatest possible har- 4 & 5d G5 | alge i * —" ™ sj Lae ios ahs eS Pe Bertie. *] : ‘ August, 1961 vest of birds without undue depletion of populations. Age ratios obtained through inspection of ducks in hunters’ bags offer valuable assistance in determining the well-being of populations and in evaluat- ing the extent to which production may be expected to replace annual losses. An average annual production of 2.7 young of flying age per adult hen has been estimated for mallards of the Mississippi Flyway in the period 1939-1955, table 58. Although this average figure and other production figures shown in table 58 are for the mallard only, they are of value in making over-all hunting regulations be- cause mallards comprise about half of the duck population. Major year-to-year changes in produc- tion of the mallard, changes that probably are present in other species also, require flexibility in regulations governing the duck kill. Production data from age ratios need to be supplemented by information from the breeding grounds in the northern part of the Mississippi Flyway. More informa- tion is needed on the effect of different combinations of regulations on mortality in the mallard and other species of ducks. Bellrose & Chase (1950:22) found evi- dence that natural losses plus hunting losses occurring under the regulations in force in the years 1939-1947 resulted in an annual mortality rate of about 48 per cent in male mallards; the annual mor- tality rate of the entire population was somewhat higher. The extent to which increased produc- tion in ducks can compensate for in- creased mortality is at present pure speculation. The ability of animals to compensate for annual variations in mor- tality rates by flexibility in production is widely recognized. More than 80 years ago, Forbes (1880:9) wrote: “The fact of survival is .. . usually sufficient evi- dence of a fairly complete adjustment of the rate of reproduction to the drains upon the species.’ A few years ago, Allen (1943 :113-4) cited the resilience of the fox squirrel in compensating for severe losses in number. Bump et al. (1947 :539- 40) reported for the ruffed grouse (Bon- asa umbellus) in New York “a distinct tendency for greater relative increases to be associated with lower breeding popula- BELLROSE et al.: SEX RATIOS AND AGE RarTIOos 467 tions.” Diem (1959: 304-5), in reporting on duck production in an Alberta study area, stated that some years “having low breeding populations have witnessed bumper crops of young.” The probability that ducks have some degree of elasticity in their capacity to reproduce is shown by differences in pro- duction among various species. It is shown further by differences in production be- tween the ducks of different flyways. Although age ratios for Nebraska mallards have tended to follow the same general trend from year to year as those in Illinois, they have consistently reflected lower num- bers of juveniles per adult, fig. 16. There is good evidence from banding and from the percentage of birds carrying shot wounds that shooting pressure is lighter in the Central Flyway (and, therefore, that the mallard undoubtedly has a lower mortality rate in that flyway) than in the Mississippi Flyway. Perhaps the ap- parently lower reproduction rate of mal- lards in the Central Flyway is the result of the lower mortality rate there. More data are needed on production and mortality rates in various species of ducks in each of the four flyways. By com- paring production and mortality rates in various species of ducks in each of the four flyways, it would be possible to learn a great deal more than is now known about an apparent inverse relationship between mortality and production and the opera- tion of other population mechanisms of waterfowl. Waterfowl population research requires a more concerted effort to appraise pro- duction and to relate this to habitat condi- tions. We recommend that state and federal biologists, working through the four flyway councils, make detailed and uniform appraisals of conditions on the breeding grounds and that, by use of age ratios obtained from bagged ducks, they determine yearly production for the im- portant species. The most feasible approach to the problem of obtaining data on age ratios appears to entail the establishment of sta- tions where large samples of particular species could be obtained. Some samples should be taken where there is evidence that a cross section of the migrating popu- lation can be obtained or where the win- 468 tering populations exhibit a minimum of regional bias. In some areas, a station might be established at which the age ratios for only one species of duck are taken. For example, in the Mississippi Flyway, the best station for sampling the mallard might be Stuttgart, Arkansas; the best for the gadwall, Mobile Delta, Ala- bama; the best for the pintail and the green-winged teal, the coastal marshes of Louisiana; the best for the ring-necked duck, Reelfoot Lake, Tennessee; the best for the redhead and the canvasback, Lake St. Clair and the Detroit River, Michigan. SUMMARY 1. The present study is an evaluation of sex and age ratios in North American duck populations and the ways in which, in waterfowl management, these ratios can be used to measure productivity. (Page 391.) 2. Determination of sex composition in duck populations presented a difficult sampling problem complicated by differ- ences in species, seasons, and places, and by inadequate sampling techniques. (Page 393.) 3. In the study reported here, most trapped or bagged ducks that could not be readily sexed by plumage differences were sexed by cloacal characters. (Page 396.) 4+. Four methods of sampling water- fowl populations for sex ratios were used: (1) examination of trapped ducks, (2) in- spection of ducks taken by hunters, (3) observation of ducks in the field, and (4+) examination of disease victims. Biases evident in each method were recognized, and corrections were made whenever pos- sible. (Page 396.) 5. Baited, funnel-type traps tended to take disproportionate numbers of drakes, while gate-type traps placed on shore tended to catch a predominant number of hens. (Pages 397, 400.) 6. Inspection of ducks in hunters’ bags made possible the separation of drakes and hens in molting adults and in juve- niles. (Page 400.) Most sex ratios derived from inspec- tion of hunters’ bags showed little bias, usually in favor of drakes. (Page 400.) 8. Banding records indicated that mal- lard drakes were 1.05 times as likely to Ittinois NaturRAL History Survey BULLETIN Vol. 27, Art. 6 be shot by hunters as were hens, the dif- ferential probably a result of hunter pref- erence for drakes. (Page 401.) 9. A few field observations on living ducks in spring were used to provide sex data on samples of several species; how- ever, because it is almost impossible to make a sufficient number of random ob- servations to insure an adequate sampling of the population of a flyway or other large area, field observations were not more extensively used. (Pages 401-2.) 10. The validity of sex ratios obtained from examination of ducks that were vic- tims of disease was found to need further study. (Page 402.) 11. Analysis of available data showed no significant departure from an evenly balanced sex ratio in ducks at fertilization or at hatching. (Pages 402-3.) 12. Data obtained from examining juvenile ducks trapped during the breed- ing season or taken by hunters during the fall indicated that the ratio between the sexes from the time of hatching to adult- hood was close to 50:50; local variations appeared to result from differences in sea- sonal movements. (Pages 403-5.) 13. Although sex ratios of adults usu- ally favored drakes, there were numerous exceptions. (Pages 405-6.) 14. Sex ratios of many species of ducks varied from week to week in any given area as the composition of the local popula- tion changed with the arrival and de- parture of flocks containing varying num- bers of drakes and hens. (Page 408.) 15. In most species of ducks for which data were available, drakes made up a smaller proportion of the hunters’ kill in Manitoba than in three states to the south (North Dakota, Illinois, and Tennessee), indicating that more drakes than hens left Manitoba in advance of the hunting sea- son. Among adult mallards bagged in Illinois, there was a steady increase in the drake segment through the third week in November, followed by a period of stabi- lized sex ratios, and then further increase in the drake segment of the wintering population, usually present in Illinois after the first week in December. In Utah, sex ratios of adult mallards bagged by hunters were relatively stable throughout fall. In only a few species did there appear to be differences in seasonal movements between August, 1961 drakes and hens in the juvenile class. (Pages 408-9.) 16. Periodic counts of ducks in late winter and early spring revealed differ- ences in the sequence of northward migra- tion of drakes and hens of the same species. (Pages 411-16.) 17. The first spring flights arriving in Manitoba showed, with minor exceptions, a closer approach to a balance between sexes than did subsequent populations. (Pages +16—9.) 18. Sex ratios in ducks were found to vary with migration routes and various areas of their wintering grounds. (Pages 419-20.) 19. Information collected on the prin- cipal mortality factors affecting the North American duck population indicates that hunters and disease take relatively more drakes than hens. This information is not sufficient to permit appraisal of the in- fluence of predation on sex ratios; how- ever, appreciable losses among hens during the breeding season, most of these losses apparently attributable to predation, agri- cultural operations, and stress, may ac- count for the predominance of drakes in the adult class. (Page 426.) 20. Data showed that, the more pro- ductive a species of waterfowl, the greater is apt to be the proportion of juveniles in its population at the opening of the hunt- ing season; the greater the proportion of juveniles in a population, the more nearly balanced is its sex ratio. (Page 426.) 21. Drakes occurred in relatively greater numbers among diving ducks than among dabblers; however, examination of the available knowledge on the reproduc- tive biology characterizing these two sub- families revealed nothing which suggests that extra drakes may be more important to the maintenance of populations of div- ing ducks than of dabblers. (Page 427.) 22. The study suggested that the value of extra drakes needs investigation through an experimental procedure designed to re- duce the number of drakes in a subpopula- tion of a species having a large drake segment. (Page 428.) 23. Sex ratios that were derived from inspection of mallards in hunters’ bags in Illinois provide a fair index to production but not so good an index as age ratios; sex ratios obtained from observations on BELLROSE et al.: SEx RATIOS AND AGE Ratios 469 the breeding grounds in Canada do not appear to provide a more reliable index to production than sex ratios calculated from bag inspections in Illinois. (Page 429.) 24. Age ratios alone, this study as- sumed, are seldom true indices of water- fowl production, but they offer a promis- ing basis for measuring it. (Page 430.) 25. In this study, age ratios were ob- tained by examination of ducks trapped for banding, shot by hunters, or killed by disease. (Page 431.) 26. Although most traps were selec- tive for adults, ducks taken in traps were found to provide a rough index to yearly changes in age ratios. (Pages 431-5.) 27. Juveniles were found to be more vulnerable to hunting than adults; the vulnerability differential varied with place, time of hunting season, year, and species. (Pages 435-9.) 28. Age ratios obtained from bagged ducks and corrected for the greater vulner- ability of juveniles offered the best means of determining the adult-juvenile compo- sition of duck populations. (Page 439.) 29. Age ratios derived from waterfowl lost to severe outbreaks of disease were considered unreliable because of the ir- regular occurrence and site limitations of such outbreaks. (Pages 439-40.) 30. Because juveniles and adults do not follow identical migration schedules or routes, age ratios showed seasonal and regional variations. (Pages 440-9.) 31. Age ratios were found to be use- ful for appraising the production of ducks if the data on which they are based have been carefully evaluated as to the effect of seasonal, regional, and shooting biases. (Page 449.) 32. A production curve (page 449) that was plotted from corrected age data for mallards in hunters’ bags in the Mis- sissipp! Flyway for 17 years, 1939-1955, follows a pattern somewhat similar to that plotted from uncorrected data and shows a somewhat rhythmic production trend that may be inherently characteristic of waterfowl populations and prove to be density dependent in origin. (Page 454.) 33. A comparison of mallard age ratios in the Mississippi Flyway with pintail age ratios in the Pacific Flyway for 11 years, 1949-1959, revealed for most years an un- expectedly close agreement between pro- 470 duction trends of the two species involved. (Pages 454-5.) 34. For the period 1952-1959, the population curve plotted from forecast in- dices of waterfowl production in Sas- katchewan was similar to the curve plotted from the Mississippi Flyway age ratios for mallards. Manitoba forecast indices showed very little correlation with mal- lard age ratios from the Mississippi Fly- way, possibly because, as aerial surveys in- dicated, about six times as many mallards nest in the plains and parklands of Sas- katchewan as in the plains and parklands of Manitoba, and because the Saskatche- wan contribution to the Mississippi Fly- way kill of mallards is larger than that of Manitoba. (Page 457.) 35. An attempt was made to correlate water conditions on the breeding grounds with mallard production. In Sasketche- wan, mallard production (as determined by the number of juveniles per adult among birds bagged in Illinois) and wa- ter abundance (as measured by the num- ber of ponds per square mile in May) fol- lowed similar trends in most years of the period 1948-1959. In Manitoba, mallard production tended to parallel water abun- dance in the years 1956-1959 but not in the 3 years previous. (Page 462.) 36. Decreased production by the mal- lard on the plains of Canada in years of very plentiful water and of cold weather, snow, and heavy rains at nesting time sug- gests that cold, excessively wet springs may be as unfavorable to duck production as dry, warm springs. (Page 463.) [Ltrnors NaturAL History SurvEY BULLETIN Vol. 27, Art. 6 37. Population density, as well as wa- ter and weather conditions on the breeding grounds, seems to have contributed to gross changes in mallard production in 1939-1959; it may well have been the dominant factor regulating production during those years in which there was poor correlation between age ratios and conditions on the breeding grounds. (Page 463.) 38. Age ratios of ducks checked in hunters’ bags in the Mississippi Flyway for the period 1946-1949 provided indices of production for the various species. Sev- eral species appear to have had about equally high production rates: mallard, black duck, shoveler, ring-necked duck, and canvasback. The baldpate and green- winged teal seem to have been intermedi- ate in production. The gadwall, pintail, blue-winged teal, redhead, and _ lesser scaup appear to have had production rates lower than those of the other species. (Page +66.) 39. Age ratios obtained through inspec- tion of ducks in hunters’ bags were found to be of value in establishing hunting reg- ulations, for they provide a basis for evalu- ating the well-being of the population and the extent to which production may be ex- pected to replace annual losses. (Pages 466-7.) 40. Further progress in waterfowl pop- ulation management, the study concluded, requires a more concerted effort to obtain age ratio data by design and to relate these data to conditions on the breeding grounds. (Page 467.) EEE RAT OO RE ChECE D Anonymous 1957. Check-list of North American birds. Fifth edition. American Ornithologists’ Union, Baltimore, Maryland. 691 pp. Allen, Durward L. 1943. Michigan fox squirrel management. Mich. Dept. Cons. Game Div. Pub. 100. 404 pp. Anderson, Maurice E. 1953. A study of the efficiency of methods of estimating duck brood production, 1952. South Dakota Department of Game, Fish and Parks, Pierre. 22 pp. Baskett, Thomas S. 1947. Nesting and production of the ring-necked pheasant in north-central Iowa. Ecol. Monog. 17(1) :1-30. Beer, James R. 1945. Sex ratios of ducks in southwestern Washington. Auk 62(1) :117-24. Bellrose, Frank C. 1944. Duck populations and kill: an evaluation of some waterfowl regulations in Illinois. Ill. Nat. Hist. Surv. Bul. 23(2) :327-72. 1955. A comparison of recoveries from reward and standard bands. Jour. Wildlife Met. 19(1):71-5. 1959. Lead poisoning as a mortality factor in waterfowl populations. Ill. Nat. Hist. Surv. Bul. 27(3):235-88. Bellrose, Frank C., and Elizabeth Brown Chase 1950. Population losses in the mallard, black duck, and blue-winged teal. Ill. Nat. Hist. Surv. Biol. Notes 22. 27 pp. Bump, Gardiner, Robert W. Darrow, Frank C. Edminster, and Walter F. Crissey 1947. The ruffed grouse: life history, propagation, management. New York State Con- servation Department, [Albany]. 915 pp. Carney, Samuel M., and Aelred D. Geis 1960. Mallard age and sex determination from wings. Jour. Wildlife Mgt. 24(4) :372-81. Cartwright, Bertram W. 1956. Waterfowl banding, 1939-1954, by Ducks Unlimited. Ducks Unlimited, Winnipeg, Manitoba, Canada. 35 pp. Second edition (revised). Cartwright, Bertram W., and Jean T. Law 1952. Waterfowl banding, 1939-1950, by Ducks Unlimited. Ducks Unlimited, Winnipeg, Manitoba, Canada. 53 pp. Colls, D. G. [1950.] Waterfowl breeding ground survey in Saskatchewan, 1950. U.S. Fish and Wildlife Serv. and Can. Wildlife Serv. Spec. Sci. Rep.: Wildlife 8:36—40. Colls, D. G., and J. J. Lynch [1951.] Waterfowl breeding ground survey in Saskatchewan, 1951. U.S. Fish and Wildlife Serv. and Can. Wildlife Serv. Spec. Sci. Rep.: Wildlife 13:35—-40. Crissey, W. F. 1954. 1954 status report of waterfowl. U. S. Fish and Wildlife Serv. Spec. Sci. Rep.— Wildlife 26. 97 pp. Diem, Kenneth L. 1959. Some aspects of wildlife population dynamics, their interpretation and role in game management. N. Am. Wildlife Conf. Trans. 24:304-11. Dzubin, Alex 1959. Growth and plumage development of wild-trapped juvenile canvasback (Aythya valisineria). Jour. Wildlife Mgt. 23(3) :279—-90. Erickson, Arnold B. 1943. Sex ratios of ducks in Minnesota, 1938-1940. Auk 60(1) :20—34. Errington, Paul L. 1943. An analysis of mink predation upon muskrats in north-central United States. Iowa Ag. Expt. Sta. Res. Bul. 320:797-924. 1945. Some contributions of a fifteen-year local study of the northern bobwhite to a knowl- edge of population phenomena. Ecol. Monog. 15(1) :1-34. Evans, Charles D. 1955. Waterfowl populations and breeding conditions in southern Manitoba, 1954. U. S. Fish and Wildlife Serv. and Can. Wildlife Serv. Spec. Sci. Rep.—Wildlife 27:71-81. Evans, Charles D., and Kenneth E. Black 1956. Duck production studies on the prairie potholes of South Dakota. U. S. Fish and Wildlife Serv. Spec. Sci. Rep.—Wildlife 32:1-59. Evenden, Fred G., Jr. 1952: eens sex ratios observed in the western United States. Jour. Wildlife Met. 16 (3) :391-3. [ 471 ] 472 ILttinois NaTuRAL History Survey BULLETIN Vol. 27, Art. 6 Forbes, 5S. A. : 1880. On some interactions of organisms. II]. Lab. Nat. Hist. Bul. 1(3):3-17. Fuller, Robert W., and Jessop B. Low : 1951. Studies in the life history and ecology of the American pintail. Utah Coop. Wildlife Res. Unit Quart. Activ. Rep. 16(3) :40-3. Furniss, O. C. 1935. The sex ratio in ducks. Wilson Bul. 47(4):277-8. 1938. The 1937 waterfowl season in the Prince Albert district, central Saskatchewan. Wilson Bul. 50(1):17-27. Geis, Aelred D. ee 1959. Annual and shooting mortality estimates for the canvasback. Jour. Wildlife Mgt. 23 (3) :253-61. Glover, Fred A. 1951. Spring waterfowl migration through Clay and Palo Alto counties, lowa. Lowa State Col. Jour. Sci. 25(3) :483-92. Gollop, J. B. ; 1954. Waterfowl breeding ground survey in Saskatchewan—1953: special study area— Kindersley-Eston. U. S. Fish and Wildlife Serv. and Can. Wildlife Serv. Spec. Sci. Rep.—Wildlife 25:65-73. Gollop, J. B., and J. J. Lynch 1955. Waterfowl breeding ground survey, Saskatchewan—1954. U. S. Fish and Wildlife Serv. and Can. Wildlife Serv. Spec. Sci. Rep.— Wildlife 27:45-55. Gollop, J. B., John J. Lynch, and William Hyska yen [1952.] Waterfowl breeding ground survey in Saskatchewan. U. S. Fish and Wildlife Serv. and Can. Wildlife Serv. Spec. Sci. Rep.: Wildlife 21:33—40. Gower, W. Carl : 1939. The use of the bursa of Fabricius as an indication of age in game birds. N. Am. Wildlife Conf. Trans. 4:426-30. Hammond, M. C. 1949. Sample variation in local waterfowl sex ratios. Miss. Flyway Waterfowl Com. News Letter 9:7-9. 1950. Some observations on sex ratio of ducks contracting botulism in North Dakota. Jour. Wildlife Mgt. 14(2) :209-14. Hanson, Harold C. 1949. Methods of determining age in Canada geese and other waterfowl. Jour. Wildlife Mgt. 13(2) :177-83. Hawkins, Arthur S. 1948. Waterfowl breeding conditions in Manitoba, 1947. U. S. Fish and Wildlife Serv. Spec. Sci. Rep. 45:39-57. 1949. Waterfowl breeding ground survey in Manitoba—1949. U.S. Fish and Wildlife Serv. and Dominion Wildlife Serv. Spec. Sci. Rep.: Wildlife 2:53-65. [1950.] Waterfowl breeding ground survey in Manitoba, 1950. U.S. Fish and Wildlife Serv. and Can. Wildlife Serv. Spec. Sci. Rep.: Wildlife 8:41-8. 1954. Waterfowl breeding ground survey in Manitoba. U. S. Fish and Wildlife Serv. and Can. Wildlife Serv. Spec. Sci. Rep.— Wildlife 25:74-80. Hawkins, Arthur S., Frank C. Bellrose, Jr., and Robert H. Smith 1946. A waterfowl reconnaissance in the Grand Prairie region of Arkansas. N. Am. Wildlife Conf. Trans. 11:394-401. Hawkins, Arthur S., and F. Graham Cooch 1948. Waterfowl breeding conditions in Manitoba, 1948. U. S. Fish and Wildlife Serv. and Dominion Wildlife Serv. Spec. Sci. Rep. 60:76-98. Hawkins, A. S., J. B. Gollop, and E. G. Wellein [1951.] Waterfowl breeding ground survey in Manitoba, 1951. U.S. Fish and Wildlife Serv. and Can. Wildlife Serv. Spec. Sci. Rep.: Wildlife 13:41-9. Hawkins, Arthur S., and Edward G. Wellein [1952.] Waterfowl breeding ground survey in Manitoba. U. S. Fish and Wildlife Serv. and Can. Wildlife Serv. Spec. Sci. Rep.: Wildlife 21:61-5. Hickey, Joseph J. 1952. Survival studies of banded birds. U. S. Fish and Wildlife Serv. Spec. Sci. Rep.: Wildlife 15. 177 pp. Hjelle, Brandt V. 1950. Bag check—1949 season. N. Dak. Outdoors 12(8):14. Hochbaum, H. Albert 1942. Sex and age determination of waterfowl by cloacal examination. N. Am. Wildlife Conf. Trans. 7:299-307. 1944. The canvasback on a prairie marsh. American Wildlife Institute, Washington, D. C. 201 pp. 1946. pAb potentials in North American waterfowl. N. Am. Wildlife Conf. Trans. 7403-16. August, 1961 BELLROSE et al.: SEX RATIOS AND AGE Ratios 473 Hopkins, Ralph C. 1947. Waterfowl management research. Wis. Wildlife Res. Prog. Reps. 5(4):12-33. Johnsgard, Paul A., and Irven O. Buss 1956. Waterfowl sex ratios during spring in Washington state and their interpretation. Jour. Wildlife Mgt. 20(4) :384-8. Jordan, James S. 1953. Consumption of cereal grains by migratory waterfowl. Jour. Wildlife Mgt. 17(2): 120-3. Jordan, James S., and Frank C. Bellrose 1951. Lead poisoning in wild waterfowl. Ill. Nat. Hist. Surv. Biol. Notes 26. 27 pp. Kabat, Cyril, R. K. Meyer, Kenneth G. Flakas, and Ruth L. Hine 1956. Seasonal variation in stress resistance and survival in the hen pheasant. Wis. Cons. Dept. Tech. Wildlife Bul. 13. 48 pp. Kalmbach, E. R. 1937. Crow-waterfowl relationships in the Prairie Provinces. N. Am. Wildlife Conf. Trans. 2:380-92. Labisky, Ronald F. 1957. Relation of hay harvesting to duck nesting under a refuge-permittee system. Jour. Wildlife Mgt. 21(2) :194-200. Lebret, T. 1950. ‘The sex-ratios and the proportion of adult drakes of teal, pintail, shoveler and wigeon in the Netherlands, based on field counts made during autumn, winter and spring. Ardea 38(1-2) :1-18. Leopold, Aldo 1933. Game management. Charles Scribner’s Sons, New York. 481 pp. Lincoln, Frederick C. 1932. Do drakes outnumber susies? Am. Game 21(1) :3-4, 16-7. Low, Jessop B. 1941. Spring flight of the diving ducks through northwestern Iowa. Condor 43(3) :142-51. Lynch, John J. 1948. Waterfowl breeding conditions in Saskatchewan, 1947. U.S. Fish and Wildlife Serv. Spec. Sci. Rep. 45:21-38. 1949. Waterfowl breeding ground survey in Saskatchewan, 1949. U.S. Fish and Wildlife Serv. and Dominion Wildlife Serv. Spec. Sci. Rep.: Wildlife 2:48-52. Lynch, J. J., and J. B. Gollop 1954. Waterfowl breeding ground survey in Saskatchewan. U. S. Fish and Wildlife Serv. and Can. Wildlife Serv. Spec. Sci. Rep.—Wildlife 25:43—54. Mann, Roberts, David H. Thompson, and John Jedlicka 1947. Report on waterfowl banding at McGinnis Slough Orland Wildlife Refuge for the years 1944 and 1945. Forest Preserve District of Cook County, Illinois. 235 pp. Mainland, Donald, Lee Herrera, and Marion I. Sutcliffe 1956. Statistical tables for use with binomial samples—contingency tests, confidence limits, sample size estimates. New York University College of Medicine, New York, N. Y. 83 pp. Mayr, Ernst 1939. The sex ratio in wild birds. Am. Nat. 73(745):156-79. Mcllhenny, E. A. 1940. Sex ratio in wild birds. Auk 57(1):85-93. Milonski, Mike 1958. The significance of farmland for waterfowl nesting and techniques for reducing losses due to agricultural practices. N. Am. Wildlife Conf. Trans. 23:215-26. Mumford, Russell E. 1954. Waterfowl management in Indiana. Ind. Dept. Cons. P.-R. Bul. 2. 99 pp. Munro, J. A. 1943. Studies of waterfowl in British Columbia: mallard. Can. Jour. Res. 21(D):223-60. Nelson, Harvey K. 1950. A study of waterfowl sex ratios during spring migration—Minnesota, 1950. Flicker 22(4) :114+20. Owen, Richard 1866. On the anatomy of vertebrates. Vol. 2, Birds and mammals. Longmans, Green, and Co., London. 592 pp. Petrides, George A. 1944. Sex ratios in ducks. Auk 61 (4) :564-71. Petrides, George A., and Charles R. Bryant 1951. An analysis of the 1949-50 fowl cholera epizootic in Texas Panhandle waterfowl. N. Am. Wildlife Conf. Trans. 16:193-216. Pirnie, Miles David 1935. Michigan waterfowl management. Michigan Department of Conservation, Lansing. 328 pp. 474 Inuinois NaTurAL History Survey BULLETIN Vol. 27, Art. 6 Rosen, Merton N., and Arthur I. Bischoff 1950. The epidemiology of fowl cholera as it occurs in the wild. N. Am. Wildlife Conf. Trans. 15:147-53. Schroeder, Charles H. 1959. No water! No ducks! N. Dak. Outdoors 22(4) :4—5. Selye, Hans 1956. The stress of life. McGraw-Hill Book Company, Inc., New York. 325 pp. Singleton, J. R. ; 1953. Texas coastal waterfowl survey. Tex. Game and Fish Comn, FA Rep. Ser. 11. 128 pp. Smith, Allen G. [1959.] Progress report: the 1959 waterfowl surveys of the Lousana study area, Lousana, Alberta, Canada. United States Bureau of Sport Fisheries and Wildlife, Wildlife Research Laboratory, Denver, Colorado. 15 pp. Smith, Robert H. 1948. Aerial reconnaissance of the Prairie Provinces. U. S. Fish and Wildlife Serv. Spec. Sci. Rep. 45:58-68. Soper, J. Dewey 1948. Waterfowl breeding conditions in Saskatchewan, 1948. U.S. Fish and Wildlife Sery. and Dominion Wildlife Serv. Spec. Sci. Rep. 60:56-75. Sowls, Lyle K. ; [1950.] Notes on the chronology of the 1950 waterfowl nesting season in southern Manitoba. U. S. Fish and Wildlife Serv. and Can. Wildlife Serv. Spec. Sci. Rep.: Wildlife 8:59-61. 1955. Prairie ducks, a study of their behavior, ecology and management. Stackpole Com- pany, Harrisburg, Pennsylvania, and Wildlife Management Institute, Washington, DaCh7193" pp. Stokes, Allen W. [1954.] Population studies of the ring-necked pheasants on Pelee Island, Ontario. Ont. Dept. Lands and Forests Tech. Bul.: Wildlife Ser. 4. 154 pp. Stoudt, Jerome H. [1952.] Waterfowl breeding ground survey of Redvers area, Saskatchewan. U. S. Fish and Wildlife Serv. and Can. Wildlife Serv. Spec. Sci. Rep.: Wildlife 21:52-60. [1959.] 1959 progress report: Redvers Waterfowl Study Area with comparative data for seven previous years. United States Bureau of Sport Fisheries and Wildlife, Wild- life Research Laboratory, Denver, Colorado. 110 pp. Stoudt, Jerome H., and Raymond J. Buller 1954. Waterfowl breeding ground survey of Redvers area, Saskatchewan. U. S. Fish and — Wildlife Serv. and Can. Wildlife Serv. Spec. Sci. Rep.: Wildlife 25:55—-64. Stoudt, Jerome H., and Marshall Stinnett 1955. Waterfowl breeding ground survey of Redvers area, Saskatchewan, 1952-1954. U. S. Fish and Wildlife Serv. and Can. Wildlife Serv. Spec. Sci. Rep—Wildlife 27:56-65. Teplov, V. F., and N. N. Kartashev 1958. Wildfowl research in Russia; biological foundations for the regulation of wild- fowling in the central districts of the European part of the U.S.S.R. Pp. 157-69 in Ninth Annual Report of the Wildfowl Trust, 1956-1957. Country Life, Ltd., London. 239 pp. Ticehurst, Claud B. 1938. On a character of immaturity in the Anatidae. Ibis, fourteenth series, 2(4):772-3. Van Den Akker, John B., and Vanez T. Wilson 1951. Public hunting on the Bear River Migratory Bird Refuge, Utah. Jour. Wildlife Met. 15(4) :367-81. Weller, Milton W. 1957. erie weights, and plumages of the redhead, Aythya americana. Wilson Bul. 69 (1) :5-38. Williams, C. S. 1953. 1953 status report of waterfowl. U. S. Fish and Wildlife Serv. Spec. Sci. Rep.— Wildlife 22. 64 pp. Yocom, Charles F. 1949. A study of sex ratios of mallards in the state of Washington. Condor 51(5):222-7. Co INDEX The following index covers Articles 1, 2, 3, 4, 5, and 6 of Volume 27 of the ILLINOIS NaTuRAL History SURVEY BULLETIN. Indexing has been limited for the most part to the names of birds, fish, insects, mammals, and plants mentioned in the articles. In most cases, the singular form of the word has been used in the index, even though the plural form has been used in the text, as mouse for both mice and mouse. Place names have not been indexed. Of necessity, variation occurs in some of the terms. For example, peach in the index may refer to either the fruit or the tree. A Abelia, 151 Abutilon theophrasti, 326 Acanthocephala (acanthocephalan), 66, 137 Acarina, 297, 300, 303, 305, 307, 309, 312, 319, 322, 339 Acnida altissima, 294, 298, 302, 304, 314, 323-4, 332-3; see also Water-hemp Aeshna, 296, 305 Aix sponsa, 254, 312, 394; see also Duck, wood Alderfly, 140 Alfalfa, 150-1, 185, 425 Algae, 16, 18, 20-2. 161. 170, 306, 308-10, 325, 355, 357-8, 380, 387 plankton, 355-7 Alisma subcordatum, 325 Alona, 12 Amaranth, green, 326 Amaranthus retroflexus, 326 Amaryliis, 158 Ambloplites rupestris, 1; see also Bass, rock Ambrosia artemistifolia, 321, 325 psilostachya, 325 trifida, 325 Ammannia coccinea, 327 Amnicola, 296, 299, 320, 338, 340 binneyana, 319 peracuta, 316 Amphibia (amphibian), 134, 136, 297, 339-40, 372 Amphipoda (amphipod), 12, 15-6, 18, 24, 27, 52, 296, 299, 305, 340 Anacharis canadensis, 326 Anas acuta, 233, 297, 393; see also Duck, pintail (American) carolinensis, 247, 303, 394; see also Duck, green-winged teal cyanoptera, 247; see also Duck, cinnamon teal diazi, 394 discors, 247, 393; see also Duck, blue-winged teal fulvigula, 394 platyrhynchos, 238, 293, 393; see also Duck ’ mallard rubripes, 257, 293, 314, 394; see also Duck, black Sstrepera, 247, 308, 394; see also Duck, gad- wall Anax junius, 299, 316 Ancylidae, 12 Anguilla rostrata, 5 Animal, 119, 125, 127-8, 132, 134, 144, 161, 180, 197-8 aquatic, 163, 178 domestic, 346 moss, 338 wild, 201 Animal foods [of waterfowl], 292-3, 295-7, 299-303, 305-23, 337-40, 343 Anisoptera, 12, 14-6, 18, 20-2, 29, 296, 299, 305, 338 Annelida (annelid), 12, 15, 22 Annuals, 145 Anser albifrons, 247; see also Goose, white- fronted Anseriformes, 191 Ant, 29, 297, 300, 305, 316, 339 Anthomylidae, 316, 339 Aphid, 100, 112, 118, 121, 132-5, 138-40 corn root, 117 pea, 118, 123 spotted alfalfa, 118, 123 Aphis, 121 A phodius distinctus, 297, 299, 309, 312, 319; see also Beetle, scarab femoralis, 312, 316 Apidae, 13 Apis mellifera, 13 Apple, 105-10, 130, 151-2 crab, 157 Apple-leaf folder, lesser, 105 Apricot, 107, 151 Arachnida (arachnoid), 137, 297, 300, 303, 305, 307, 309, 316, 319, 322, 339 Araneae, 12, 16, 18, 22, 300, 316, 319 Arbor vitae American, 146 Chinese, 146 Siberian, 146 Ardes herodias, 65 Argia apicalis, 12 Argiopoidea, 300, 322 Armyworm, 114-5, 117, 123 fall, 123-4 Arrenurus, 12 Arrowhead, common, 300, 337 Arthropoda, 296, 299, 303, 305, 307, 309, 312-4, 316, 319-20, 322, 338 Asellus, 12, 15, 296, 299, 305 communis, 15 Ash, 158, 160 mountain, 157 wafer, 151 Aster, 158 Ataenius, 13 Avena sativa, 327; see also Oats Avens, 327 Aythya, 430 affinis, 239, 315, 393; see also Duck, lesser scaup americana, 254, 321, 394; see also Duck, red- head [ 475 | 476 A ythya—continued ' collaris, 254, 317, 393; see also Duck, ring- necked marila, 23%, 323; see also Duck, greater scaup valisineria, 238, 320, 394; see also Duck, canvasback Azalea, 158 B Backswimmer, 296, 338 =~ Bacteria, 27, 77, 147, 153, 161 Bagworm, 118 Barley, 117, 151 Bass, 165, 171-2, 176, 353-6, 362-5, 367, 371-2, 375-7, 379-88 black, 164 largemouth, 5-6, 10-3, 22-3, 28-9, 36, 49, 62, 68-77, 79, 164, 170, 172-8, 345, 353-4, 359- 61, 365-6, 368, 370-1, 374, 376, 378-382, 384, 387 rock, 1, 43 smallmouth, 5, 72, 74-6, 79, 175-6, 178 spotted, 5 yellow, 5 Bean, 152 navy, 326 trailing wild, 326 wild, 326 Beaver, 196 Bedbug, 104, 123 Bee, 29, 121, 135 bumble, 100 Beet, 111 Beetle, 29, 129, 142 asparagus, 105 bark, 118 bean leaf, 118 carpet, 123 Colorado potato, 104-5, 109, 111-2, 115, 123-4 corn flea, 151 cucumber, 111 diving, 296, 299, 303, 305, 307, 309, 312, 314, 316, 319-20, 322, 339 ground, 296, 299, 303, 305, 312, 316, 319-20, 339 Japanese, 104 June, 135, 143 leaf, 135, 297, 300, 305, 307, 313, 319, 339 Mexican bean, 104 rove, 135) 296, 299, 305, 312,-339 scarab, 297, 299, 307, 309, 312, 319, 339 snout, 106, 297, 300, 303, 316, 320, 339 water, 135, 322 water scavenger, 296, 299, 314, 316, 339 whirligig, 296, 303, 305, 312, 319, 339 Beggar-tick, 325 Begonia, 158 Belostoma, 13 Belostomatidae (on some pages misspelled Belastomatidae), 13, 296, 299, 319, 338 Benacus, 319 Berosus, 13 Bidens frondosa, 325 Billbug, 117 Birch, 118 Bird, 86, 96, 105, 120-1, 129-30, 136, 179-81, 183-4, 188, 206, 210 Intinors NarurAL History Survey BULLETIN Volume 27 fish-eating, 164 game, 181, 183, 199 migratory game, 182 nongame, 182-3 song-, 198 upland game, 182, 186 water, 205 Blackberry, 152 Blackbird, red-winged, 121 Blastobasidae, 144 Blight, 112 Blissus leucopterus, 116-7; see also Bug, chinch Blue jay, 186 Bluegill, 4-6, 8-10, 39-40, 62, 67-9, 71-2, 74-6, 172-3, 176-8, 345, 353-6, 362-8, 370-88; see also Lepomis macrochirus Bobwhite, see Quail Bonasa umbellus, 467 Bootjack, 337 Borer clover root, 118 elm, 154 European corn, 104, 112, 122-3, 143 flat-headed, 118 flatheaded wood, 296, 339 peach tree, 108 round-headed, 118 squash vine, 111 stalk, 117 tree, 108 Branchiopoda, 305, 338, 340 Branta canadensis, 239, 425; see also Goose, Canada Bream, 71 Bruchus granarius, 105 Bryophyte, 161 Bryozoa (bryozoan), 12, 16, 20, 22, 296, 299, 303, 305-8, 312, 316, 319, 322, 338, 340 Bucephala albeola, 259; see also Duck, buftehead clangula, 247, 323; see also Duck, common goldeneye Buckeye, 158 Buckwheat climbing false, 294, 324 common, 325 Buftalo, 128 Buffalo [fish], 164, 172-3 mongrel, 172 redmouth, 172 Bug, 29, 86, 89, 91, 114 chinch, 93, 114-7, 121, 123-4, 296, 299, 338 plant, 140, 338 squash, 316, 339 stink, 139, 296, 339 water, 296, 299, 319, 338 Bullhead black, 5, 172, 176 yellow, 5 Bulrush alkali, 322, 325 American, 292, 325 green, 325 hard-stem, 309, 318, 325 river, 196, 309, 318, 321, 323, 325, 334, 337, 343 soft-stem, 292, 309, 318, 321, 325 Buprestidae, 13, 296, 339 Bur-reed, 193 J Y. ay