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' DOOD OA Kaw) Haan on a ay ey i OOO L aoa a. nia hia Pt mail ai * i Or in Ys) one Panel vanes ye) PAH ANI Nee ein solace Pah ,, Payee A kN i alee A oo X) eshte Aes ‘sileh eek taka wh ay Ne Ras yy} PRRARRRHNS a Hee Sh i : : “1 ate free 28 ei ihieee eteth ean Sa ts by " + se BW ay : x ne int es Sasi: Rens Sa NES : uy va SETS: aes ANN at Nit oy rae > AAD Bib ihet SERRE Mae vi ee . oe 5 ys MORE RETR) * ‘ hAoaantainat us Arana o ache siale nana eae Wilyals ent Sie NN RRR RRR Y oh SHARAN , ix) ROC RTA T S Ah f toh i BRSuh Va , eae my free Wu ee : rigsat'st : x Det) Mths Weaa’y RAEN YEN Wy hey HA HocNy sedan keen Ure Wivaracocty ait Oni i) i } hay saan Weiere taal Rea Med ‘ irae aetaty ha) ni ; ° 5 iY Aye aalila lias Miata aaa ta: KR , Cut mK) reeks bbe ks bb 4 eae aaah ie GNIS ENGR i ahd at) me) “ * \ i" One a AS ? 4 rita Ae, é tN BR fo a oy) ih , Maas ahh y AON Cua ANON otis a i s wieh.s , 7444 wea HW SHAN AN ath Pea ane Y as fy Dantes ite: My AERC NEM MLSNI haa hs sa aa asd fayey Gy Ot be Laue 02 F x ue be wee o SN Ath = WEN aa heh Sa RAG yh VA, ORIENT YAH ales way vale D 1 Par Rah Aas Ys i wl G99 VEN Oa a ci th ND Pela nas NO DODO MARLO th SARE AEN 09 D A. yy a SORE KHAN RNR vie Unk he Aaa Ae ‘ Me RANMA STUN ahaha rsa " MODOC KTR RIL) ca eysey a SNe HAAN The Hk eR y % Naty ca rn) RENEERR ERK ea ik ae DURAN % aig i cei) Pa hci Why na Nay Werk ison Se Soe yy MRR OR ER RI Wt, i Ris ace av ya aaah 4 i Hates acaiae aah ware Site ve i AY iti AK abe Vane Wels Sia aay uit PRR H 4 y) y 0 tei rans . ’ ( oie i ee OO: DO ROME RE RA MT AR SN * ins i Syuveate ie ie bey i ‘ nae) HOMME EU Ree \ AA alg t ive t Ah “3 : ed ‘ "4 iy We 4 ipa + Hi ¥ wad Na) Yk vv ete Dak SANS ntelaNe rtd + ae t Ai * 4 ' i SHEN a Hp 4 4 A Re KN eaters EY WRT) Ss CREA COLTS TECHS sy, ai ui K BWC He o ee = * Waser us ty ei <- aiate += a rs a we: 14% Fate Ve bw Cee Ne eases oes re poe ne a = ae > * we oy AWA vel aace * ‘ Daina Y Sait & Sh it sy, Kini rae eet EEN NTC HS ei Kony vs, ‘a eal 4 Wea 4 MAR ons D * ‘ Men SEs aaa a sae +4 ban cy wae ee he ie UNIVERSITY OF CALIFORNIA PUBLICATIONS ZOOLOGY WILLIAM EMERSON RITTER AND CHARLES ATWOOD KOFOID EDITORS VOLUME 11 WITH 26 PLATES £304\3 UNIVERSITY OF CALIFORNIA PRESS BERKELEY 1912-1914 + on pony CONTENTS PAGES 1. Birds in Relation to a Grasshopper Outbreak in California, by Harold C. Bryant bo . On the Structure and Relationships of Dinosphaera palustris (Lemm.), by Charles A. Kofoid and Josephine R. Michener ....21—28 3. A Study of Epithelioma Contagiosum of the Common Fowl, by Gifford Di Sweet) ApriysO- MOOG ase cate eS Ee UN a eg 05 4. A- New Harvest Mouse from Petaluma,.California, by Joseph Dixon, Pp, 273-278.) Aupnst 4451909 ee ae es a ees eS 05 5, A New Cowbird of the Genus Molothrus, with a note on the Probable Genotic Relationships of the North American Forms, by Joseph Grinnell. Pp: 275-281, 1 text figure. December, 1909......22....22-28. 05 6. Two New Rodents from Nevada, by Walter P. Taylor. Pp. 283-302, platos 27-29, 7. A Northern Coast Form of age California Gray Fox, ‘by Joseph Dixon. Pp. 308-305. : Nos. 6 and 7 in one cover. February, 1910..2..20-.022- 20 8. Two Heretofore Unnamed Wrens of the Genus Thryomanes, by. Joseph Grinnell. Pp. 307-309, $. The Savannah Sparrow of the Great Basin, by Joseph Grinnell. Pp. 811-316, 10, A Second Record of the Spotted Bat (Buderma maculatum) for Qali- fornia, i Joseph Grinnell. - Pp.-317-320, plate 30. Nos. 8, 9,.and 10 in one cover... February, 1910.0... IB * Roman numbers indicate sequence of the Contributions from the Laboratory of the Marine Biological Association of San- Diego. UNIVERSITY OF CALIFORNIA PUBLICATIONS IN ZOOLOGY Vol. 11, No. 1, pp. 1-20 November 1, 1912 BIRDS IN RELATION TO A GRASSHOPPER OUTBREAK IN CALIFORNIA BY HAROLD C. BRYANT Professor Samuel Aughey, one of the pioneers in economic ornithology, spent twelve years studying the relation of birds to the periodic outbreaks of the Rocky Mountain locust in Ne- braska. Over 630 individuals, representing ninety different species of birds, were examined. The investigation showed that ““in locust years these insects became the chief food of insect- eating birds, even water-birds devouring them largely.’’ Prae- tically every kind of bird from the tiny kinglet to the huge pelican fed on the locusts to some extent. The determination of the relation of birds to a grasshopper outbreak in California, where widely different environmental conditions exist, is of interest. It will be seen that the present investigation substantiates the findings of Professor Aughey, and demonstrates that here also birds feed on the insect most avail- able, and are therefore important agents in helping to maintain the balance in nature most suited to the interests of man. Keonomie ornithology has progressed to the point where in- tensive studies are demanded. Each state with its varied en- vironmental conditions should know the economic status of the birds within its borders. California, under the auspices of the State Fish and Game Commission and the University of Cali- fornia, is carrying on an investigation into the food habits of some of the birds of the State about which repeated complaints have arisen from agriculturists and horticulturists. Field in- vestigations in combination with examinations of the stomachs 2 University of California Publications in Zoology (Vou. 11 of birds collected each month of the year in over twenty differ- ent parts of the State, are furnishing positive data as to the food of these birds throughout the year. The feeding habits of birds at the time of an insect outbreak, such as that of the differential grasshopper (Melanoplus differentialis) which oc- curred in the San Joaquin Valley in the summer of 1912, afford critical evidence of the value of birds as insect destroyers, and of their part in maintaining that balance in nature most suited to the interests of man. It is impossible, however, to determine accurately the full value of birds, for we cannot find out what the result would be upon the insect population, if all the birds were suddenly de- stroyed. Yet a knowledge of their food leads us to conjecture that the destruction of so important an enemy of insects as the birds would result in a great Increase in these enemies of vegeta- tion and thus cause a serious disturbance in the balance of nature. The fact that birds destroy large numbers of injurious insects shows them to be important agents in contributing to the safety not only of crops, but also of all vegetation. A realization of the usefulness of birds promotes needed interest in and protec- tion for them. It is hoped that, as a result of this investigation and others in progress, the insectivorous habits of many of the common birds, and their consequent value, may be more generally known and appreciated by those who most profit by their activities; and also that this study of the relation of birds to a particular out- break may add something of permanent value to the too meager knowledge of the part played by birds in maintaining the desired balance in nature. In the investigation here described an attempt was made to answer the following questions: 1. What species of birds in California feed on grasshoppers during the periodical outbreaks of these insects ? 2. To what extent does each species at such times feed on grasshoppers as compared with other food? 3. How many, and what proportion, of grasshoppers are destroyed by birds at the time of an outbreak. 1912] Bryant: Relation of Birds to a Grasshopper Outbreak 3 4. In what measure may birds be instrumental in preventing and controlling grasshopper outbreaks and what regulatory ac- tion may they have at other times? Certain sections of California are annually troubled with grasshoppers, and there is seldom a year when they do not cause considerable damage in some part of the State. (See Woodworth, 1902, and Hunter, 1905.) Reports of damage caused by grasshoppers in 1912 first began to appear in June. The western part of Merced County, and parts of Kings and Kern Counties, were most affected. The present investigation was largely carried on in the vie- inity of Los Banos, Merced County, this being one of the worst centers of infestation. A comparison of the bird population in the infested area was made possible by a census taken in the vicinity of Mereed, a city in the western part of the county. Alfalfa, pasture, grain, and a little fruit, form the principal erops raised in and near Los Banos. Grasshoppers give some trouble in this vicinity each year, but in 1912 their depredations were more extensive than usual. Grasshoppers were abundant enough to do serious damage in only three districts in the near vicinity of Los Banos. The area most infested is known as “Section Four,’’ one of the ranches of the Miller and Lux Com- pany, eight miles west of the town. The Midway Ranch, four miles east, was badly infested and a slight infestation existed one and a half miles south. On the two ranches mentioned the entire summer crop of alfalfa was destroyed. Burning over of pasture and of alfalfa land was the only control measure resorted to. As most of the grasshoppers already had wings when the burning was done, most of them escaped unharmed. Fields of alfalfa outside of the infested districts looked well, and many of them were being cut. Garden vegetables and small trees in the infested areas suf- fered. Corn, tomatoes, and onions were stripped of every leaf. Small shade trees, including eucalyptus, were also defolated. A single species of grasshopper, Melanoplus differentialis, the differential grasshopper, caused the damage. In pasture land a few grasshoppers of the species Camnula pellucida were ecol- 4 University of California Publications in Zoology (Vou. 11 lected. The only other species noted were Conozoa behrensi and Parapomala calamus. Many of the ranchers believed that the grasshoppers had migrated hither from other parts of the county. It appeared, however, that the insects were hatched either in the alfalfa fields themselves or in nearby pasture land. Practically no movement was noted except the usual drifting with the wind when the in- sects were frightened. Some evidence was obtained that they slowly moved from one alfalfa field to a neighboring one in search of food. Computation of the numbers per square yard in the infested areas was obtained by counting the numbers disturbed by the observer at each step. Little damage could be noted where the grasshoppers were less than fifteen to the square yard. Where damage was greatest, alfalfa fields averaged about twenty-five to the square yard. In some pasture land along the canals, the numbers were estimated at thirty per square yard. Los Banos, largely on account of its great irrigation system and the large amount of land which has been swamped, supports a very large bird population. Water-birds and shore-birds are very abundant along the canals and in the marshes, whereas the pasture lands, alfalfa, and the trees, furnish food and cover for many land birds. During the week’s stay, July 10 to 17, 1912, twenty-two species of water- and shore-birds were recorded, and forty species of land birds. A census of birds taken on two successive afternoons on a walk along roads and through fields west of town furnishes one with an idea of the numbers and the comparative abundance of the different species. The first was taken while covering a dis- tance of about three miles, and occupied the time between three and four-thirty o’clock. The second was taken while covering a distance of four miles, and occupied the time between two-thirty and four-thirty o’clock on July 12, both in the same infested territory. Some idea of the bird population in the infested dis- tricts compared with that in other parts of the county can be obtained from a third census taken in the vicinity of Merced, in a non-infested region. The counts were made in this instance while driving about twenty miles north and east of Merced. The 1912] Bryant: Relation of Birds to a Grasshopper Outbreak 5 The two regions are similar in the general character of the land and crops, but an error may have been introduced in the censuses, due to the facet that I walked through one region and drove through the other. The larger amount of swamp land in the vicinity of Los Banos also accentuates the contrast in the two censuses. time occupied was four hours, one to five in the afternoon. BIRD CENSUSES Number of birds seen in infested in non-infested areas area Great Blue Heron Ardea herodias herodias 2 2 Anthony Green Heron Butorides virescens anthonyi 3 2 Black-crowned Night Heron Nycticorax nycticorax naevius 4 8 Black-necked Stilt Himantopus mexicanus 2 2 see Killdeer Oxyechus vociferus 4 29 5 Western Mourning Dove Zenaidura macroura marginella 3 17 13 Burrowing Owl Speotyto cunicularia hypogaea 1 2 Red-shafted Flicker Colaptes cafer collaris ess 1 bts Western Kingbird Tyrannus verticalis 9 23 31 Black Phoebe Sayornis nigricans 2 2 1 California Horned Lark Otocoris alpestris actia 2 fe 31 Bicolored Red-wing Agelaius phoeniceus californicus 252 290 245 Western Meadowlark Sturnella neglecta 36 67 17 Bullock Oriole Icterus bullocki 8 10 9 Brewer Blackbird Euphagus cyanocephalus 1 4 15 English Sparrow Passer domesticus 6 4 22 Linnet Carpodacus mexicanus frontalis 3m 20 34 Green-backed Goldfinch Astragalinus psaltria hesperophilus — .... 3 Heermann Song Sparrow Melospiza melodia heermanni 4 1 ace Western Lark Spartow Chondestes grammacus strigatus 1 2 3 Western Blue Grosbeak Guiraca caerulea lazula Ht Lazuli Bunting Passerina amoena a 3 soot Cliff Swallow Petrochelidon lunifrons lunifrons 85 66 18 Barn Swallow Hirundo erythrogastra 74 78 56 California Shrike Lanius ludovicianus gambeli 6 14 9 Long-tailed Chat Icteria virens longicauda 3 1 RX FH Foo eee 2 Re eee 345 649 479 Average number seen per mile ~................. se lili 162 24 Average number seen per acre .................... 9 13 1 The figures indicate that the red-winged blackbird was the bird most abundant. Next in order of abundance were cliff swallows, barn swallows, western meadowlarks, linnets, western kingbirds, and shrikes. The difference in the numbers seen per 6 University of California Publications in Zoology (Vou. 11 mile on the two successive afternoons, July 11 and 12, is doubt- less due to the fact that on July 12 more of the wooded portion along canals was included, and also to the fact that more flocks of red-wings were seen. That the bird population in the vicinity of Los Banos is at least twelve times that found to be in the vicinity of Merced, is a safe statement. The larger amount of swamp land near Los Banos furnished food and cover for large flocks of red-winged blackbirds and also for many species of water-birds. With increased cultivation and irrigation, and a consequent increase of insect life, the bird population should be expected to increase in the vicinity of Merced. In determining by observation the birds feeding on grass- hoppers, only those birds actually seen with grasshoppers in their bills were recorded. The list is as follows: Western Meadowlark Sturnella neglecta Bicolored Red-wing be wheat? Glycocoll 0.0 1.1 0.02 0.9 0.4 Alanine 21 + 2.0 2.66 0.3 Valine ie 2 2.4 0.21 0.33 tes Leucine Gaus ee THO 5.61 6.00 4.1 Serine ial os 0.13 0.12 aoe Aspartie Acid 1.5 0.5 0.5 1.24 0.7 Glutamie Acid 8.0 12.2 Bison toleo 24.0 Cystin 0.38 ee Ob es: ast Phenylalanine 4.4 2.8 2.35 2.6 1.0 Tyrosine 2.48 1.6 1.20 2.37 1.9 Proline 2.25 3.3 7.06 2.4 4.0 Oxyproline =tee See resto) orca = Tryptophane aoe eee a 1.0 + Histidine as ses 0.61 ilet/ 1.2 Arginine ee = 3.16 3.4 4.4 Lysine tes as 0.0 0.0 2.2 Ammonia sae rae OAM 28s 2.5 1 Abderhalden and Pregl (1905). ? Levene and Beatty (1907). 8K. Morner (1901). 4 Abderhalden and Hunter (1906). 5 Osborne and Clapp (1906). ® Abderhalden and Samuely (1905), and Abderhalden (1909). 7 Abderhalden and Malengreau; Kossel and Kutscher. 78 University of California Publications in Zoology (Vou. 11 In the analyses of various cleavage products, table 10, ghadin and gluten are notable for their high percentage of glutamic acid. Glutamic acid is noted by Abderhalden and Guggenheim as an inhibitor of the tyrosinase reaction when tyrosinase from Russula delica is used. Accordingly ghadin and gluten (made from white flour, dried, ground, and fed in powdered form) were fed to different sets of tadpoles. These foods produce so little growth that the results are very inconclusive. The results with lhver, yolk and gliadin are as follows (table iMl)) 2 TABLE 11 Length measurements of Hyla tadpoles fed on liver, yolk, and gliadin. Length measurements represent average length of all the tadpoles in a dish. Hyla. Experiment started Feb. 24, 1912 Mar. 5 Mar. 25 —— =) om a) Length Number of Length Number of Food in mm. tadpoles in mm. tadpoles Liver 15.8 18 Bees 0 Yolk 15.3 18 28.0 14 Gliadin 12.5 18 15.0 15 Mar. 5. Liver-fed tadpoles black. Gliadin-fed tadpoles dark, but not so dark as liver, yolk-fed tadpoles lighter with a few very light ones. Mar. 14. Liver-fed tadpoles all black; yolk-fed tadpoles—four very light, the rest medium; gliadin, one light, the rest medium. Of three sets of Rana tadpoles one was fed on raw flour, one on gluten, and the third on gliadin. Here again the growth was so slight that the experiment was unsatisfactory (table 12) : TABLE 12 Length measurements of Rana tadpoles fed on flour, gluten, and gliadin. Length measurements represent the average length of all the tadpoles. Equal number of tadpoles at the beginning of the experiment. Rana. Experiment started Feb. 24, 1912 Length in mm. Number of tadpoles Feed Mar. 6 Mar. 25 May 6 Flour NYE 19.1 9 Gluten 15.8 18.5 iL Gliadin 1G fe ecoeets Mar. 25. No noticeable color difference. Apr. 10. Only one gluten-fed tadpole left. This one is larger and slightly darker than the average of the flour-fed tadpoles. 1913] Johnson: Pigment Formation in Amphibian Larvae 79 The same experiment with Hyla tadpoles gave the following data (table 13) : TABLE 13 Length measurements of Hyla tadpoles fed on flour, gluten, and gliadin. Length measurements represent the average length of all the tadpoles in a dish. Hyla. Experiment started Feb. 24, 1912 Length in mm. Food Mar. 6 Mar. 24 Flour 13.0 18.3 Gluten 13.3 19.6 Gliadin 12.2 13.7 Mar. 24. Tadpoles all nearly the same color,—if any difference gluten- fed are darkest, gliadin-fed lightest. Gortner (1911b) finds that orcin, resorcin, and phloroglucin inhibit the action of tyrosinase extracted from potatoes, meal worms, and the periodical cicada. He says: “‘It would appear from these data, that aromatic compounds which carry two hydroxyl groups in meta position to each other may act as chemical anti-oxidases on tyrosinase, and completely inhibit its action. Other oxidases are not inhibited, but are able to oxidize these same m-dihydroxl compounds, forming colored bodies of an unknown nature.’’ Phloroglucin and resorcin were mixed with liver and fed to Hyla tadpoles. The amounts were not weighed, but about fifteen milligrams was rubbed up with the liver and put into the dish. The tadpoles on resorein did not thrive, most of them died very soon (table 14) : TABLE 14 Length measurements of tadpoles fed on liver, liver + resorein, and liver + phlorogluein. Measurements represent the average length of all the tadpoles in the dish. Hyla. Experiment started Mar. 18, 1912 Mar. 25 Apr. 11 Length Number of Number of Food in mm. tadpoles tadpoles Liver 14.1 6 6 Liver + resorein * 15.4 4 0 Liver + phloroglucin 14.3 6 4 80 University of California Publications in Zoology [Vou 11 Mar. 25. Alltadpoles the same color. Apr. 1. All tadpoles the same color. Apr. 11. Of the four remaining tadpoles on liver plus phloroglucin, two are as dark as the six tadpoles fed on liver alone, and two are slightly lighter. The same experiment with albumen as food gives the follow- ing results (table 15) : TABLE 15 Length measurements of tadpoles fed on albumen, albumen + resorcin, and albumen + phloroglucin. Measurements represent the average length of all the tadpoles in the dish. Hyla. Experiment started Mar. 18, 1912 Length in mm. Food Mar. 25 Albumen 13.6 Albumen + resorein 13.1 Albumen + phloroglucin 12.8 Mar. 25. Tadpoles fed on albumen plus phloroglucin are very slightly lighter than the other two sets, which are both the same color. Apr. 11. Tadpoles fed on albumen plus phloroglucin are very slightly lighter than those on albumen, but the difference is scarcely noticeable. This group of experiments, as will be noted, was tried but once and with a small number of tadpoles, so they can be regarded only as a beginning in this direction. The results indicate that the various substances may affect the color of the tadpoles to some extent. H. HISTOLOGICAL DIFFERENCES BETWEEN CHROMATOPHORES OF LARVAE FED UPON DIFFERENT FOODS The statements as to the color differences in the tadpoles have been made thus far on the basis of their appearance to the unaided eye. The differences as shown by the microscope are no less marked and show plainly that there is actually less pigment in the egg-fed tadpoles (plate 1). With the low powers of the microscope the black epidermal chromatophores of the dark Rana tadpoles appear to be greatly branched, and so filled with pigment that they come very close 1913] Johnson: Pigment Formation in Amphibian Larvae 81 together, while in the light egg-fed tadpoles, the chromatophores, though perhaps not less numerous are more slender and delicate and very little branched. In very lhght specimens the pigment is In spots that are scarcely elongated at all (pl. 1, figs. 5-8). The form of the chromatophores in the Hyla is somewhat different. The body of the chromatophore is not so long, but the branching processes are longer and finer and in dark individuals form a close network of fine interlacing branches (pl. 1, figs. 3 and 4). Between the two extremes in both species are various grades of difference, so that the chromatophores of an unusually dark ege-fed tadpole may not differ greatly from those of a lighter colored liver-fed individual. A study of sections shows that the chromatophores of the dark tadpoles are larger because they contain many more of the brown melanin granules. These granules are so numerous that the pigment forms a continuous network in the intercellular spaces, while in the light tadpoles the amount of melanin is so much less that the pigment masses appear as small spots with few or no processes. Camera drawings of the typical chromatophores of the two sorts make this difference clear. Sections of epidermis of larvae of Rana sp. X 450. (Drawn with aid of camera lucida.) Fig. A. Tadpole fed on yolk of egg. Fig. B. Tadpole fed on liver. 82 University of California Publications in Zoology (Vou. 11 I. EFFECT OF CHANGES IN LIGHT, HEAT, AND FOOD UPON PIGMENTATION To determine the influence of light and heat upon the color differences produced in the tadpoles by different foods, the fol- lowing experiment was carried out. Eight dishes of tadpoles, all from the same bunch of eggs, were arranged as shown below. Warm: (In dark. (a. fed toueasee In constant temperature, box (of (in black paste- 2 ; glass) kept at about 26.5 C. board box) (2: Fedyoneyols < ; c. fed on liver In light. uf L |d. fed on yolk Cold: In dark. ( : ; n fed! liv In north basement room. (The [ (in black paste- : reruns temperature of this room varied board box) Le fed on yolk er ata Pes con- SRM. fo Anil aa eer sidera p n light. iderably below ordinary room ig je MeSAs oni Olle temperature. ) L : TABLE 16 Length measurements of Rana tadpoles under different conditions of light, temperature, and food. Measurements are average length of all the tadpoles in a dish. Experiment began with eight tadpoles in each lot. Rana. Experiment started Feb. 10, 1912 March 5 Conditions of the experiment A ~ Length Number Temperature Lighting Food in mm. living Warm Dark Liver 28.0 3 Warm Dark Egg yolk 27.5 5 Warm Light Liver 31.4 4 Warm Light Egg yolk 26.5 2 Cold Dark Liver 19.3 8 Cold Dark Egg yolk 20.8 8 Cold Light Liver 21.2 8 Cold Light Egg yolk 20.3 8 AVERAGES CON! deseo sees deaccecastctsheseeesecncecesecer ete 20.4 32 AWA) ew eek heceesteccd eset eee 28.6 14 edo it: sn-2ete ee tee 2 22 Dart? *xccvec den tees 23.0 24 Egg yolk 22.6 2 Liver 23.2 23 1913] Johnson: Pigment Formation in Amphibian Larvae 83 The series of colors is the same under the different conditions of temperature. In both cases the series from darkest to lightest coloring is as follows: Darkest tadpoles—Those fed upon liver and kept in the light. Those fed upon egg and kept in the light. ss Those fed upon liver and kept in the dark. Lightest tadpoles—Those fed upon egg and kept in the dark. It is plain from this experiment that tadpoles raised in the light are darker than those raised in the dark and that tadpoles fed upon liver and kept either in the light or in the dark are darker than those fed upon egg under the same conditions. The differ- ence in size and development between the tadpoles kept at a high temperature and those in the low temperature are so great that the two series cannot well be compared, but no marked difference in color between the two series can be distinguished. It is evident that changes in both food and light influence the rate of pigment formation markedly and that light is a somewhat more potent factor than liver in increasing the rate of pigment production, These conclusions as to increase of pigmentation in the light and increase in the rate of growth at a higher temperature con- firm results already reported (table 16). The average length measurements of all tadpoles kept in the dark compared with those kept in the light are interesting in view of the conflicting statements that have been made by various observers as to the comparative rate of growth in the dark and in the light. These figures support the contention that there is very lttle if any difference between the amount of growth in the light and in the dark. J. SUMMARY A consideration of Weismann’s theory, the factor hypothesis, and the results of chemical research, leads one, it seems to me, to see in the last two named the greatest hope for the solution of problems of color differentiation. The difficulties and com- plications are great, but the field for research is correspondingly large and fruitful. 84 University of California Publications in Zoology (Vou. 11 The present research is by no means complete, the results so far attained suggesting numerous very pertinent points that should be investigated farther. It does, however, furnish certain definite facts which it is hoped will add something to current conceptions of color differentiation. The research shows that pigment in Rana and Hyla tadpoles is not correlated with amount of nutrition, as claimed by Tornier for Pelobates larvae, but, as suggested by instances cited by Darwin and Wallace, is dependent rather upon substances specifie for color in the nutritive material. These substances may bring about a change in the amount of pigment-forming sub- stances produced or slightly alter the character or combination of these substances and thus change the amount or color of the pigment. The fact is made clear that lecithin acts as a partial inhibitor of the tyrosinase reaction in the test tube, and when it is fed to tadpoles, pigment formation is checked to a noticeable degree, indicating that inhibitors or modifiers of the pigment formation may be introduced into the organism with the food. The similarity of the effect of lecithin in the test tube and in the body of the tadpole makes it probable that the tyrosinase reaction or a similar oxidase reaction is the basis of pigment formation in the tadpole. BIBLIOGRAPHY ABDERHALDEN, E., AND GUGGENHEIM, M. 1907. Versuche iiber die Wirkung der Tyrosinase aus Russula delica auf Tyrosin, tyrosinhaltige Polypeptide und einige andere Verbindungen unter verschiedenen Bedingungen. Zeit. f. physiol. Chem., 54, 331-353. ABDERHALDEN, E., AND HUNTER, A. 1906. Hydrolyse des im Eigelb des Hiihnereies enthaltenen Protein’: (‘*Vitellin’’). Zeit. physiol. Chem., 48, 505-512. ABDERHALDEN, E., AND PREGL, F. 1905. Die Monoaminosiuren des krystallisierten Eieralbumins. Zeit. physiol. Chem., 46, 24-30. ABDERHALDEN, E., AND SAMUELY, F. 1905. Die Zusammensetzung des ‘‘Gliadins’’ des Weizenmehles. Zeit. physiol. Chem., 44, 276-283. 1913] Johnson: Pigment Formation in Amphibian Larvae 85 BERTRAND, G. 1908. Recherches sur la mélanogénése: Action de la tyrosinase sur la tyrosine. Ann. Inst. Pasteur, 22, 381-389. CastiE, W. E. 1907. On a ease of reversion induced by ecross-breeding and its fixa- _tion. Sci., n.s., 25, 151-153. Castie, W. E., in collaboration with H. E. Wavrer, R. C. MULLENIX, and S. Coss. 1909. Studies of inheritance in rabbits. Publ. Carnegie Inst., Wash- ington, no. 114, pp. 69, 4 pls., 4 figs. in text. Cuopat, R., AND Staus, W. 1907. Nouvelles recherches sur les ferments oxydants. III, La spéci- ficite de la tyrosinase et son action sur les produits de la dégradation des corps protéiques. Arch. Sei. Phys. (4), Genéve, 24, 172-191. DANILEWSEY, B. 1895. De l’influence de la lécithine sur la croissance et la multiplica- tion des organismes. C.-R. Aead. Sci., Paris, 121, 1167-1170. Darwin, C. 1868. The variation of animals and plants under domestication. Authorized ed., with a preface by Prof. Asa Gray. (New York, Orange Judd & Co.), vol. i, x + 494, 43 figs. in text, vol. ii, vili + 568. DewiTz, I. 1902. Recherches expérimentales sur la métamorphose des insectes. G.-R. Soe. Biol., Paris, 54, 44-45. GESSARD, C. 1901. tudes sur la tyrosinase. Ann. Inst. Pasteur, 15, pp. 593-614. Gouprars, A. J. 1910. Does lecithin influence growth? Arch. f. Entwicklungsmechanik, 29, 255-274. GorTNER, R. A. 1910a. The origin of the brown pigment in the integuments of the larva of Tenebrio molitor. Journ. Biol. Chem., 7, 365-370. 1910b. Spiegler’s ‘‘white melanin’’ as related to dominant or reces- sive white. Amer. Nat., 44, 497-502. 191la. Studies on melanin. II, The pigmentation of the adult periodi- eal cicada (Tibicen septendecim L.). Journ. Biol. Chem., 10, 89-94, 1 pl. 1911b. Studies on melanin. III, The inhibitory action of certain phenolie substances upon tyrosinase. Journ. Biol. Chem., 10, 113-122. 191le. Studies on melanin. IV, The origin of the pigment and the color pattern in the elytra of the Colorado potato beetle (Leptino- tarsa decimlineata Say). Amer. Nat., 45, 743-755. 1911d. On melanin. Biochem. Bull., 1, 207-215. HAMMARSTEN, OLAF. 1911. A text-book of physiological chemistry. Authorized translation by John A. Mandel. (New York, Wiley), viii + 964 pp., 1 pl. 3 tables. 86 University of California Publications in Zoology (Vou. 11 Kastip, J. H. 1909. The oxidases and other oxygen-eatalysts concerned in biological oxidations. Pub. Health and Marine-Hospital Service, U.S., Hyg. Lab. Bull., no. 59, 164 pp. Kine, H. D. 1907. Food as a faetor in the determination of sex in amphibians. Biol. Bull., 13, 40-56. LEVENE, P. A., AND BEaTty, W. A. 1907. Ueber die analyse der Spaltungsprodukte des Eialbumins. Bio- chem. Zeit., 4, 305-311. Morner, K. A. H. 1901. Zur Kenntniss der Bindung des Schwefels in den Proteinstoffen. Zeit. physiol. Chem., 34, 207-338. OsBorNE, T. B., AND CLapp, S. H. 1906. The chemistry of the protein bodies of the wheat kernel. Part IIf. Am. Jour. Physiol., 17, 231-265. PHISALIX, C. 1905. Sur le changement de coloration des larves de Phyllodromia germanica. C.R. Soe. Biol., Paris, 59, 17-18. PuimMER, R. H. A. 1908. The chemical constitution of the proteins. (London, Longmans), vol. i, xii + 100 pp., vol. ii, xi + 66 pp. Powers, J. H. 1908. Morphological variation and its causes in Amblystoma tigrinum. Studies from Zool. Lab. Univ. Nebraska, 71, 77, 9 pls. RIDDLE, O. 1908. The genesis of fault-bars in feathers and the cause of alterna- tion of light and dark fundamental bars. Biol. Bull., 14, 328— 370, 4 pls., 5 figs. in text. 1909. Our knowledge of melanin formation and its bearing on the Mendelian description of heredity. Biol. Bull, 16, 316-351. ROMANES, G. J. 1895. Darwin, and after Darwin. An exposition of the Darwinian theory and a discussion of post-Darwinian questions. II, Post- Darwinian questions, heredity and utility. (Chicago, Open Court), x + 344, 1 pl., 4 figs. in text. RoqQuEs, X. 1909. Sur la variation d’une enzyme oxydante pendant la métamor- phose chez un Trichoptére (Limnophilus flavicornis Fabr.). C.-R. Acad. Sei., Paris, 149, 418-419. . TORNIER, G. 1907. Nachweis iiber das Entstehen von Albinismus, Melanismus und Neotenie bei Fréschen. Zool. Anz., 32, 284-288. 1908. Vorliufiges iiber experimentell erzielten Hautalbinismus bei Axolotl-larven. Berlin, Sitz Ber. Ges. nat. Freunde, 1908, 66-67. _———— a | eh ead - LN eee — = RP EXPLANATION OF PLATE 1 Fig. 1. Rana sp. The lighter tadpole was fed upon yolk of egg, the darker one was fed upon liver. From photograph, natural size. Fig. 2. Hyla regilla. The lighter tadpole was fed upon yolk of egg, the darker one was fed upon liver. From photograph, natural size. Figs. 3-8. Epidermal chromatophores of amphibian larvae. From photographs, magnified about forty-five diameters. Fig. 3. Hyla regilla. Tadpole fed on liver. Fig. 4. Hyla regilla. Tadpole fed on yolk of egg. Fig. 5. Rana sp. Chromatophores of tail region, tadpole fed on liver. Fig. 6. Rana sp. Chromatophores of tail region, tadpole fed on yolk of egg. Rana sp. Chromatophores of body of larva, tadpole fed on liver. | = iQ | Fig. 8. Rana sp. Chromatophores of body of larva, tadpole fed on yolk of egg. [88] [JOHNSON] PLATE |. ALIF. PUBL. ZOO UNIV. VOL. OCKAYNE—BOSTON UNIVERSITY OF CALIFORNIA PUBLICATIONS ~ Note.—The University of California Publications are offerec in exchange for the publi- eations of learned societies and institutions, universities and libraries. Complete lists of all the publications of the University will be sent upon request. For sample copies, Lists ef publications or other information, address the Manager of the University Press, Berkeley, California, U. 8. A. All matter sent in exchange should be addressed to The Exchange Department. University Library, Berkeley, California, U, S. A. OTTO HARRASSOWITZ, BR. FRIEDLAENDER & SOHN, LEIPZIG. 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February, 1909 00... 20 ® Boman numbers indicate sequence of the Contributions from the Laboratory of the Marine ithe Association of San Diego. gy, UNIVERSITY OF CALIFORNIA PUBLICATIONS IN ZOOLOGY Vol. 11, No. 5, pp. 89-126, pl. 2 June 21, 1913 SAGITTA CALIFORNICA, N.SP., FROM THE SAN DIEGO REGION INCLUDING REMARKS ON ITS VARIATION AND DISTRIBUTION BY ELLIS L. MICHAEL INTRODUCTION After publishing the results of a long and critical study of the chaetognatha of the San Diego region involving the indi- vidual identification of nearly 80,000 specimens, a few net-hauls made in October, 1911, unexpectedly yielded what the former prolonged search failed to reveal—a new species. Popping, as it were, into existence so suddenly and being the only new chaetognath taken from California waters, this species has seemed to me to take appropriately the name, Sagitta californica. While certain very apparent characteristics of this new species seemingly make it impossible to confuse it with any other, still it sometimes happens that specimens are described as con- stituting a new species when the differential characteristics upon which the definition is based later prove to be abnormalities or extremes of variability within an old species. I have endeavored to guard against such a pitfall by making accurate diagnostic measurements on aS many specimens as practicable, and to this end table 1 is supplied, which is based upon micrometer measure- ments of fourteen structural features in each of one hundred of the most perfectly preserved specimens. In addition to this the 90 University of California Publications in Zoology (Vou. 11 number of teeth and seizing jaws possessed by each individual, and the stage of maturity of ovary and seminal vesicle in each individual, are recorded. It is therefore hoped that the data in table 1 will materially aid future investigators in definitely settling questions of synonymy in the event of another similar species being discovered. Again, much confusion occasionally arises because the nature as well as extremes of specific variation is not known, and its exposition constitutes one of the erying needs in the descrip- tion of species. Pearl (1911, p. 110) has fully expressed this need as follows: ‘‘The systematist frankly makes no attempt whatever to deseribe or define a particular species as a species— in terms of its (the species) qualities. Instead he describes one individual animal belonging to this species; affirms either ex- pressly or tacitly that all other individuals belonging to the species are ‘‘about’’ or ‘‘generally’’ like the individual described, and then he calls the net results the definition or description of the species. But now surely this is not a description of the species at all. An adequate description of the species will be one which takes account of its peculiarities as a unit, and indi- cates how it as a unit or as a whole is distinguished from other similar groups.’’ Now the data compiled in table 1 afford an excellent opportunity for determining many of these important specific characteristics relative to variation and correlation in the several proportional measurements and number of teeth and seizing jaws. Therefore, following the customary descrip- tion some space is devoted to this purpose. However, it is not my intention, had I the ability, to plunge the reader into the intricacies of biometrical analysis, though that might be desir- able, but it is attempted so to arrange and analyze the data that all who read may readily comprehend. ? DESCRIPTION GENERAL APPEARANCE.—To the naked eye 8S. californica, when placed in formalin upon a white background, assumes a very light yellowish-green color. It is palest about the neck and tip of tail, and shades gradually into a slightly deeper tint in the region of the ovaries. The brown seizing jaws, alone, stand out 1913] Michael: Sagitta californica from San Diego Region 91 conspicuously. On a black background the head, intestine, ven- tral ganglion, ovaries, and seminal vesicles appear much more opaque than the body proper which, like the tail, is translucent, nearly semi-opaque. The lateral fins, as well as tail-fin, are readily recognized as very transparent areas in decided contrast to the body. In degree of opacity S. californica resembles S. serratodentata more than any other species, although it is more translucent than is the latter. The presence of numerous tactile hairs (pl. 2, fig. 1) extend- ing from head to seminal vesicles, reveals, to the naked eye, a pronounced serrated appearance, especially between the head and ventral ganglion. These hairs occur most abundantly along the anterior half of the collarette. In older individuals, from four to twelve may be present on each of the paired fins and on the tail-fin. These hairs, like those in S. bipunctata and other species, are rendered much less conspicuous after long preservation in either alcohol or formalin. CHaArActTERS.—Body very firm and rigid, retaining its form almost perfectly. Neck and constriction at tail-septum promi- nent, but rendered inconspicuous by the collarette. Body slightly widest throughout middle third, tapering very gradually toward head and tail. Lateral fields small. Muscles thick and strong. Corona ciliata not observed. Collarette (pl. 2, fig. 1), massive and very long, extending from head to tail-septum, and thence to seminal vesicles. Broad- est just behind head (13-14 per cent of maximum body-width), gradually narrowing caudally until, opposite the posterior end of anterior fins, it is only about 3 per cent of the maximum body-width. From here it may vary slightly in width until it disappears at the tailseptum. Behind this structure, the col- larette reappears and broadens regularly until it attains a width of about 12 per cent directly anterior of the seminal vesicles. It then very abruptly narrows, disappearing entirely at the vesicles. Anterior fin shorter and narrower than posterior fin, varying in length from 16.5 to 21.8, and in width from 1.65 to 3.35 per cent of total length of animal. It approaches closely to but does not reach the ventral ganglion, the interval varying from 0.76 92 University of California Publications in Zoology (Vou. 11 to 2.83 per cent of total length of animal. Form approximately triangular, the position of greatest width being opposite the rounded obtuse angle in the caudal fourth of the fin. Posterior fin varies in length from 19.4 to 26.4, and in width from 2.96 to 5.27 per cent of total length of animal. It ap- proaches but never reaches seminal vesicles, the interval varying from 2.19 to 4.60 per cent of total length of animal. More than 50 per cent of fin in front of tail-septum, the extremes of variation being 51 and 61 per cent. Position of greatest width about half way between tail-septum and posterior extremity of fin. Interval from anterior to posterior fin varies from 11.7 per cent of total length of animal in the younger individuals to 5.90 per cent in the older ones. Vestibular ridge (pl. 2, fig. 2), provided with irregularly rounded papillae, so arranged that one papilla is usually opposite the interval between adjacent teeth. However, some intervals are skipped, so that the number of teeth is greater than the number of papillae, notwithstanding the fact that two or three papillae occur internally to the teeth. One tooth, sometimes two and rarely more, project beyond wing of ridge, the adjacent one usually being well covered by it. Notch covers the external four or five teeth. External process short and blunt, scarcely one and a half times longer than broad. Anterior teeth (pl. 2, fig. 3), three to seven, usually five or six. They are closely set, with overlapping bases. Very divergent distally. Posterior teeth (pl. 2, fig. 2), eight to sixteen, usually ten or eleven. They are closely set and overlapping, though less markedly than anterior teeth. Slightly divergent distally. While they are nearly of the same width (at the base) as the anterior teeth, they are much longer, the longest anterior tooth being only two-thirds as long as the shortest posterior tooth. Seizing jaws (pl. 2, fig. 4), seven to ten, usually eight or nine. Curvature 41 to 51 per cent. Points with an oval base and imbedded from 20 to 25 per cent of their height into the shaft. Top of shaft and base of point converge in approaching edge of jaw. Edge of point nearly straight while the back is considerably curved. Pulp-canal displaced considerably toward 1913] Michael: Sagitta californica from San Diego Region 93 back of jaw, and extending into point from 60 to 70 per cent of its height. Pulp evenly distributed throughout canal. Ovaries (pl. 2, fig. 1), long and slender. The mature ovary varies in length from 21.6 to 26.9 (in one ease 32.3) per cent of total length of animal, and in width from 5.2 to 7.8 per cent of its length. It extends, when mature, beyond the posterior limit of anterior fin, although it never reaches the anterior limit of fin. Ovaries approaching maturity have not been noted in individuals under 22.1 mm. in length. Ova small even when mature. S. californica is readily distinguished from all other species of Sagitta by its long collarette. In S. planktonis this structure extends caudally to the ventral ganglion, and in S. ferox to the anterior fins. In all other species its limit hes anterior to the ganglion. Thus the fact that the collarette extends in S. cali- fornica from head to seminal vesicles makes it utterly impossible to confuse it with any other known species. TABULAR MBASUREMENTS.—AS in my previous paper (1911) I have endeavored to include enough measurements in table 1 to enable a fairly accurate reconstruction of the outline of each individual considered, when taken in connection with the fore- going description. In addition, whenever the right ovary differed conspicuously in length from the left one, both were measured, and in the table the length of the left ovary appears below that of the right one. In anterior and posterior teeth and seizing jaws the number in both right and left rows is given, the latter following the former. Finally the following symbols are used to designate the stage of maturity in ovary and seminal vesicle: iny.— invisible. vy. rem.—very remote from maturity. rem.—remote from maturity. imm.—immature. w. dev.—well developed. appr.—approaching maturity. mat.—fully mature. 94 University of California Publications in Zoology |Vou. 11 TABLE 1 MEASUREMENTS OF Sagitta californica’ : Tail és Anterior fin Posterior fin : =a é =I cr =A (= —__—- —— | H a 2a ar) ex é 3 3s s =| E2 $s ce = =a} 3 & FI i a ee ee en hs. Z rs] = a Se pals a = 2& a Ee 2s 1 9°68" 4555) (30:9) 78) SalS is) 227 ese) STS toe L000 2 3:55 4155) 27:9 Tb Tale lv Wi9b) 195, (2450) - 4822) aae70 3 14.46 494 266 69.2 5.70 205 2.28 0.76 24.0 3.42 7.60 4 15.30 4.60 281 700 690 201 230 115 23.6 3.45 8.05 oO H o for} Or is for) a bo a oO for) Je} for) a — wo Lol 2 ol onl oO a — a @ bo (Ot) i=) ise) a for) = S oe o 21 21.20 4.56 27.4 71.00 538 21.2 3.11 1.24 25.3 ~°4.98 7.46 22 21.25 5.36 28.1 69.9 5.36 19.8 3.10 1.24 25.6 4.95 7.43 23 21.30 455 29.4 71.5 4.96 165 1.65 248 22:33 3.31 11.20 24 21.35 5.35 25.5 69.0 5. a for) bo i=) a bo He “1 a a Or bo [or) ns os rs 7.82, on aay ws a =) uy St) ) = 25 21.45 4.91 28.7 70.9 1.23 23.3 . 4.10 9.43 1 All measurements, unless otherwise noted in table, given in per cent of total length of animal. ? Per cent of posterior fin in front of tail septum. 1913] Posterior fin to seminal “ vesicle 2.78 3.10 2.63 2.96 2.94 3.78 2.49 3.32 2.90 2.48 3.72 2.88 3.28 2 Given in per cent of length of ovary. 4The + indicates that the ovary extends beyond anterior limit of posterior fin, the — that it falls short of that point. 54.0 52.0 54.0 51.5 51.0 Length a cad eee 0.53 3.90 2.64 11.40 3.17 13.70 0.79 5.20 0.70 4.50 0.97 5.86 1.14 6.85 1.14 6.44 1.23 6.80 1.23 6.76 1.32 7.18 1.05 5.55 1.41 7.40 1.67 8.40 1.41 7.02 1.94 9.32 2.02 9.66 1.93 9.13 1.93 9.14 2.02 9.55 2.28 10.70 1.76 8.30 2.81 13.20 2.55 11.90 2 to pos- terior fin* Vis rem. i imm. Vv. Vv. Vv. Vv. rem. rem. y. rem, y. rem, y. rem. 7. rem. y. rem. 7. rem. y. rem. rem. rem. y. rem. rem. Vv. rem, rem. rem. Michael: Sagitta californica from San Diego Region MEASUREMENTS OF Sagitta californica' Stage of maturity . imm, imm. - rem. . Tem. . imm. imm. rem. imm. imm. Posterior Anterior teeth teeth Seizing jaws + Number ip oo for) (e ) ew we <2 a ~ | _ w no > uo to Number a bo “ 50 96 , Length in mm. bo = 22.85 22.95 University of California Publications in Zoology (Vou. 11 to bo © Length ey Ch bo = bo TABLE 1—Continued MEASUREMENTS OF Sagitta californica’ Tail to ventral <- ganglion for) vo) ot ganglion & orLength of ven- =) S tral ou Anterior fin A. Posterior fin ee ERY @ = SF a fq A Ff 21.8 2.84 162 23.0 445 6.48 19.0 2.82 2.02 238.8 4.43 8.85 20.4 2.20 240 248 4.40 6.00 19.2 3.20 1.20 23.6 4.80 8.80 19.6 3.00 1.20 25.6 4.80 7.60 19.1 279 159 235 418 8.25 21.1 259 159 243 418 7.57 19.5 2.59 1.59 23.1 4.41 9.75 20.2 1.98 1.98 246 4.36 9.51 20.2 318 159 25.8 437 7.15 19.8 2.76 1.58 249 4.55 7.50 SLO 2:96 IC Sa 245 aro: 7.50 19ST Salo 1.57 24.4 3.74 8.16 19.3 2.36 1.18 23.6 3.94 9.45 20.1 3.35 1.57 25.6 4.33 5.90 19.7 «62.76 VOT. 24:8 “3:15 7.86 19 273) 95) 2324 450) 7.81 20:3. 2.93 1:56 24.2 5.08 7.04 19.8 2.72 156 245 4.28 7.40 20:6 234 7:56 249 3:50 7.00 20.66 253 117 25.3 447 7.00 18.2 2.32 1.93 23.6 3.48 9.26 18.8 2.69 1:54 24:6 3:46 9.22 19.6 3.07 1.54 25.0 4.61 7.70 18.8 2.49 1.92 249 © 3.83 7.65 1 All measurements, unless otherwise noted in table, given in per cent of total length of animal. ? Per cent of posterior fin in front of tail septum. 1913] Michael: Sagitta californica from San Diego Region 97 TABLE 1—Continued MEASUREMENTS OF Sagitta californica’ Posterior fin Ovary Stage of maturity Number of 3 A = iS Si Length Width = be A ms ‘a2 EI — em, 39-7 Dy fo = & x 2 ne ; : : : a 3 ost P=] =| aa = in in per in in per e =i == 2S : E es 13} mm. cent mm, cent® fo) nS ag 2 o = 3.24 53.0 2.02 O30 9 O03 6.53 v.rem. imm. 5-6 10-11 8-8 26 mon 51:0 (2:72 12:50 0.18 6.45 imm. imm. 5-5 10-10 8-9 27 3.60 53.0/ 2.90 13.20 0.26 9.10 imm, w. dev. 6-5 10-11 8-9 28 3:20 51.0 2.55 11.60 0.26 10.30 — 0.40 rem. mat. 5-5 10-10 8-8 29 3:60) 52:5 92:20 10:00 0.18 8.00 — 2.40 yv.rem. imm. 6-6 11-11 8-9 30 3.58 52.5 3.96 17.90 0.26 6.70 + 5.60 imm. mat. 3-4 10-10 8-7 31 2.39 52.5 2.55 11.60 0.18 6.90 — 1.20 rem. w.dev. 6-6 12-? 8-8 32 3.72 52.0 2.02 10.70 0.18 8.70 — 3.26 rem. imm. 5-5 9-9 7-8 33 + 5.15 w.dev. mat. 6-6 11-11 8-9 34 3.57 51.0 4.40 19.90 0.35 8.00 -+ 6.75 appr. mat. 6-6 11-11 9-9 35 Caio) 2251 948 0.22 10.40 — 3.56 rem. we.dev. 5-6 10-11 9-9 36 3.16 51.5 4.48 20.20 0.40 8.82 fi a appr. mat. 5-5 10-11 9-9 37 3.15 52.0 2.38 10.60 0.35 14.80 i 7 imm. mat. 5-6 12-12 8-7 38 2.76 52.0 2.64 11.80 0.31 11.70 — 0.39 rem. w.dev. 5-5 10-10 9-8 39 2.36 55.0 4.40 19.70 0.35 8.00 + 5.50 w.dev. w.dev. 5-5 15-14 9-9 40 3.15 54.0 4.40 19.70 0.35 8.00 + 6.30 w.dev. imm. 7-7 16-15 9-9 41 ae 3.52 53.0 2.99 13.30 0.22 7.35 0.78 rem. mat. 6-6 11-11 9-9 42 3.12 51.5 3.08 13.70 0.22 Lory xem: appr. 5-4 89 8-8 43 3.90 52.0 2.64 11.70 0.26 10.00 —1.17 rem. mat. 5-4 10-10 8-8 44 3.11 53.0 1.76 7.30 0.18 10.00 — 545 v.rem. imm. 5-4 10-10 9-9 45 2.72 52.0 2.99 13.20 0.22 7.35 + 0.00 rem. imm. 44 9-8 8-8 46 348 51.0 1.93 8.50 0.18 9.10 — 3.48 rem. imm. 6-6 11-11 9-9 47 2:69 51.5 3.96 17.30 0.31 7.80 4.61 imm. mat. 4-4 10-10 8-8 48 It + 3.46 54.0 3.08 13.50 0.26 8.56 0.00 rem. w.dev. 5-5 11-10 9-9 49 3.45 52.0 4.75 20.70 0.35 7.40 7.65 w.dev. mat. 7-5 14-14 9-9 50 + 3 Given in per cent of length of ovary. 4The + indicates that the ovary extends beyond anterior limit of posterior fin, the — that it falls short of that point. 98 University of California Publications in Zoology {Vou 11 TABLE 1—Continued MEASUREMENTS OF Sagitta californica’ . Tail 2 Anterior fin Posterior fin I 8 6 r aS > (— 5 a ie) ie Su Sg S = a BS ee z] 5 BS a Z g = Sp Woe aoe 3 Sess os 2 51 22.98 5.75 28.0 69.7 4.98 20.3 1.92 1.53 24.9 3.83 52 23.02 5.34 27.9 70.0 5.73 20.2 2.10 1.53 23.6 4.00 53 23.15 5.14 28.5 70.4 5.70 20.2 2.09 1.14 25.1 3.70 54 23.30 5.28 268 686 565 204 2.26 113 23.4 3.02 70 24.00 5.13 27. 5 71 24.00 5.50 27.8 70-6 5.50 19.4 2:93 1:47 24.9 3:66 72 24.00 5.50 27.5 69:6 550 183 2.20 2:20 23.4 3.30 73 24.05 5.48 27.4 70.5 5.11 200 2.74 1:83 248 4.01 74 24.10 6.20 266 69.0 548 204 219 1.82 244 3.83 75 24.10 5.28 27.0 69.4 5.84 19.7 256 219 234 3:65 >' to anter- 9 jor fin wn 7.30 8.02 1 All measurements, unless otherwise noted in table, given in per cent of total length of animal. * Per cent of posterior fin in front of tail septum. 1913] Michael: Sagitta californica from San Diego Region TABLE 1—Continued MEASUREMENTS OF Sagitta californica‘ Posterior fin Ovary Stage of maturity Number of = SSK: —— g ; oF Length Width E = K 5 Es L= : A RG a >» BH zB $i Be as aw AB in in per in in per AcE S BG ao oo i is mm, cent mm. cent* sep ©) ne <2 ye 2.68 51.0 2.72 11.90 0.18 6.45 — 0.75 rem. mat. 6-6 11-11 30D) (92:0) 3:52 15.30 = 0.35 10.00 + 3.06 imm. w.dev. 5-? 10-11 3.12 13.50 11.30 + 1.34 3.42 53.0 4.57 19.80 0.26 5.77 + 646 imm. appr. 6-6 10-9 4.53 58.0 2.55 10.90 0.35 13.80 — 1.13 appr. mat. 6-6 12-12 2.99 12.80 11.80 + 1.51 8.02 52.0 5.18 22.20 0.85 6.80 + 9.80 appr. mat. 6-6 15-16 3.40 52.5 3.78 16.20 0.35 9.30 + 3.77 imm. mat. 2? 11-11 3.02 52.0 6.60 28.30 0.44 6.66 +15.50 mat. appr. 5-5 9-9 BHA 53.0 3.16 13.50 0.22 6.95 + 0.37 imm. appr. 5-5 11-10 Sei 51.0 4.40 18.70 0.35 8.00 + 7.45 w.dev. mat. 6-6 12-12 4.22 17.90 8.30 + 6.71 1.86 54.0 5.19 22.00 0.48 9.34 + 8.20 w.dev. mat. 6-7 12-12 2.60 52.0 7.65 32.30 0.40 5.20 +19.30 mat. mat. 5-6 12-12 2.97 53.0 4.67 19.70 0.40 8.50 + 7.06 appr. mat. 6-6 12-11 4.32 18.20 9.18 + 5.58 3.74 52.0 4.84 20.40 0.35 7.30 + 7.40 w.dev. mat. 6-6 13-13 3.70 51.0 4.40 18.50 0.40 9.00 + 6.30 w.dev. mat. 5-5 12-11 2.96 54.5 5.36 22.60 0.40 7.40 + 9.25 appr. mat. 7-7 14-14 Sith 52.5 4.66 19.60 0.35 7.59 + 7.40 w.dev. mat. 6-6 11-11 3.30 53.0 4.66 19.50 0.40 8.50 + 6.98 w.dev. mat. 6-6 13-13 3.32 54.5 5.72 24.00 0.44 7.19 +11.40 appr. appr. 7-6 13-14 3.31 51.5 5.90 24.60 0.44 TAT +11.30 appr. mat. 5-6 2-14 SO olla 3.40 14.30 0.44 12.80 + 1.46 appr. mat. 5-6 12-12 3:66 545 3.87 16.10 0.35 910 + 2.57 imm. appr. 5-5 13-13 3.66 53.0 4.67 19.40 0.35 7.59 + 6.96 w.dev. w.devy. 6-6 11-11 3.64 54.0 7.12 29.50 0.35 4.95 +16.00 appr. mat. 6-6 13-12 6.50 27.00 5.40 +13.50 2.19 52.0 4.93 20.40 0.85 7.15 + 7.65 w.dev. w.dev. 6-? 14-14 4.40 18.30 8.00 + 5.47 4.00 53.0 6.15 25.60 0.40 6.44 +13.10 appr. mat. 5-5 11-12 Given in per cent of length of ovary. 4The + indicates that the ovary extends beyond anterior limit of posterior fin, the — that of that point. 99 s 6 a E Uees a 9-9 51 8-8 52 9-8 53 9-9 54 8-8 55 8-7 56 8-8 57 9-9 58 8-9 59 8-8 60 9-9 61 8-9 62 9-9 63 8-8 64 8-9 65 9-8 66 8-8 67 9-9 68 1-8 69 9-9 70 9-8 71 8-9 72 8-8 73 8-8 74 9-8 =I ut it falls short 100 University of California Publications in Zoology (Vou. 11 TABLE 1—Concluded MEASUREMENTS OF Sagitta californica’ & Tail i Anterior fin Posterior fin | Es SSS SS om As =—-\ =| ro Pa & Ee St Es a 3 = r=] = ze Ss S = = =) = 2 Z 4 = a Sr siz 4 = 2% A = Be 76 24.20 5.10 27.6 68.0 5.45 21.4 2.90 1.45 24.4 4.36 8.00 77 24.25 5.61 27.2 68.8 5.44 19.9 1.81 1.45 23.5 3.62 8.33 78 2495 5.80 27.5 69.2 5.43 18.8 2:36 1.82 23.2 3.98 8.34 79 94.95 4.71 261 68:8 5.80 19:2 2.64 217 23.0 4.35 8.34 98 25:50) 5185 (28-0) 7010) foal? ON eae eT 2 24a oer 7.93 99 25:65 548 26:7 70:0 5:15 20:2 2106 I-71 23:6) S277 7.88 100 25.95 5.42 284 694 5.09 193 2.03 2.03 23.7 3.72 7.45 1 All measurements, unless otherwise noted in table, givem in per cent of total length of animal. * Per cent of posterior fin in front of tail septum. 1913] Michael: Sagitta californica from San Diego Region 101 TABLE 1—Concluded MEASUREMENTS OF Sagitta californica‘ Posterior fin Ovary Stage of maturity Number of —* = === + = = 3 i * = Length Width 5 = ks 5 bh a2 a A oS >. ne. Gas Je 2 3 oa in in per in in per Ace 3S ‘2S == aS is a 2? mm. cent mm. cent® BS 3 ne seminal vesicle 12-14 14-16 16-18 18-20 20-22 22-24 24-26 Total 2.0-2.4 na ABE 1 1 3 3 2 10 (33) (14) (17) (7) (7) 2,.5-2.9 oon buss 2 a 6 9 5 26 (67) (57) (33) (21) (18) 3.0-3.4 aes if ets 2 4 aii 8 32 (50) (29) (22) (40) (29) 3.5-3.9 5 13 vg 29 (28) (30) (39) 4.0—-4.4 3 2 2 (7) 4.5-4.9 1 1 2 (50) (2) Total 0 2 3 7 18 43 28 101 r=+0.165 +0.0653 Inspection of this table shows that, with two exceptions, the larger intervals are found only in the larger animals. Further- more, inasmuch as the proportion of the population (see numbers 108 University of California Publications in Zoology (Vou. 11 in brackets) possessing the interval measuring 2.5-2.9 per cent decreases as the length of animals increases, while the propor- tion possessing the larger interval measuring 3.5-3.9 per cent increases as the length of animals increases, it is evident that there is a pronounced tendency toward positive correlation in spite of the smallness of the coefficient (7 = -+0.165). Again, the fact that the majority of animals between 16 and 22 mm. have an interval measuring 2.5-2.9 per cent, while the majority of those between 22 and 24mm. have an interval of 3.0—-3.4 per cent, and the majority of those between 24 and 26 mm. have an interval of 3.5-3.9 per cent—points once more toward positive correlation. Finally, the following averages of interval measure- ments, excepting that for animals 14 to 16mm., increase with considerable uniformity as the animals increase in length, point- ing again toward positive correlation. Here are the averages: 4.00 per cent for animals between 14 and 16 mm. 2.58 per cent for animals between 16 and 18 mm. 2.82 per cent for animals between 18 aad 20 mm. 3.05 per cent for animals between 20 and 22 mm. 3.26 per cent for animals between 22 and 24mm. 3.36 per cent for animals between 24 and 26mm. LenetH oF Ovary.—Excepting the articles by Ritter-Zahony (1908, 1910) and myself (1911), nothing has been published in which the ovary has been considered of specific importance. Its exclusion has been due to the fact that the ovary is the last structure to develop, so that one could find ovaries of any size in specimens otherwise fully mature. Nevertheless its average and maximum extent and correlations with the length of animal, as in table 6, reveal important characteristics for the species. While this table, together with the coefficient (r= —+-0.8998), shows that the ovary increases in Jength much faster than the animal does, it also shows (1) that ovaries measuring less than 5 per cent were not found in animals over 16mm. in length, and (2) that ovaries measuring more than 15 per cent were not found in animals under 22mm. in length. Since we find (see table 1) that the ovary does not reach maturity until its length is over 20 per cent of that of the animal, these facts show that 1913] Michael: Sagitta californica from San Diego Region 109 TABLE 6 CORRELATION BETWEEN LENGTH OF ANIMAL AND PROPORTIONAL LENGTH OF OVARY Proportional Length of animal in mm. length of =) ovary 12-14 14-16 16-18 18-20 20-22 22-24 24-26 Total 0-4 4 2 6 (100) (29) 5-9 Stee 3 5 12 14 5 2 41 (52) (100) (100) (48) (6) (4) 10-14 2 15 27 2 46 (29) (52) (33) (4) 15-19 32 18 50 (39) (32) 20-24 15 19 34 (18) (33) 25-29 1 16 aly, 1) (28) 30-34 2 2 (2) Total 4 7 5 12 19 82 57 196 r== +0.8998 +0,0092 the ovary in S. californica does not mature in individuals under 22mm. in length. The table, however, tells us more than this. Mere cursory examination reveals the following facts: 1. In animals under 14 mm. the ovary is less than 5 per cent in length. 2. In animals 14 to 16 mm. the ovary is less than 15 per cent in length, and in the majority it varies between 5 and 10 per cent. 3. In the majority of animals 16 to 20mm. the ovary varies from 5 to 10 per cent in length. 4. In the majority of those 20 to 22mm. the ovary varies from 10 to 15 per cent in length. 5. In the majority of those 22 to 24mm. the ovary varies from 15 to 20 per cent in length. 6. In the majority of those 24 to 26mm. the ovary varies from 20 to 25 per cent in leneth. Again, the average proportional length of ovary, correspond- ing to each group of animals differing by 2mm. in length, as calculated from table 6 and as obtained directly from table 1, is as follows: 110 University of California Publications in Zoology (Vou. 11 Length of animal Calculated Actual in mm. average average 12-14 2.5 per cent 3.9 per cent 14-16 7.5 per cent 8.7 per cent 16-18 7.5 per cent 6.2 per cent 18-20 7.5 per cent 7.0 per cent 20-22 10.1 per cent 10.8 per cent 22-24 16.7 per cent 17.0 per cent 24-26 21.5 per cent 21.7 per cent Comparison of the calculated and actual averages reveals little difference, especially in the larger and more numerous animals. It is quite safe, therefore, to conclude that, if based on a fairly large number of measurements, the average length of ovary in S. californica will vary with the length of animals measured, as follows: 5 per cent in animals between 0 and 14mm. —10 per cent in animals between 14 and 20 mm. —15 per cent in animals between 20 and 22 mm. 1 2 9 per cent in animals between 22 and 24mm. 5 per cent in animals between 24 and 26mm. Lenetu or Tatt.—Preparing a correlation table, as given below, between length of tail as measured in per cent and length of animal, we see that there is very little if any definite relation between the larger animals and proportional length of tail. TABLE 7 CORRELATION BETWEEN LENGTH OF ANIMAL AND PROPORTIONAL LENGTH or TAIL Proportional Length of animal in mm. length of tail 12-14 14-16 16-18 18-20 20-22 22-24 24-26 Total (14) (6) 26 a= 1 a 2 1 4 5 13 (33) (29) (6) (9) (18) 27 1 1 2 2 9 24 16 55 (50) (33) (67) (29) (50) (56) (57) 28 a J 1 4 12 7 26 (33) (33) (14) (22) (28) (25) 29 1 3 3 7 (14) (16) (7) 30 1 i (50) Total 2 3 3 7 18 43 28 104 r= —0.0858 +0.06565 1913] Michael: Sagitta californica from San Diego Region 111 While the correlation coefficient is negative ( r= —0.0858), thereby indicating that the body increases in length faster than the tail, the probable error is relatively so large (= 0.0656) that this appearance is most likely due to chance. It is evident from inspection of the table that the majority of animals between the lengths of 20 and 26 mm. have tails lying between 27 and 28 per cent. Furthermore the next most abundant number have tails lying between 28 and 29 per cent. Moreover, when the average lengths for the tail corresponding to each group of animals are caleulated they show more clearly the absence of any definite correlation. Such averages are as follows: -9 per cent for entire population (12-26 mm). -6 per cent for animals between 24 and 26mm. 1 per cent for animals between 22 and 24mm. -9 per cent for animals between 20 and 22 mm. 2 per cent for animals between 18 and 20 mm. -8 per cent for animals between 14 and 16mm. 5 0 co a per cent for animals between 14 and 16mm. cent for animals between 12 and 14mm. bd bw bw Ww Ww Wb bb Rs) uo) o a Thus, excepting those animals between 12 and 14 mm., the average length of tail hes between 27 and 28 per cent, irrespec- tive of the length of animal. It is quite probable, therefore, that, between the lengths of 14 and 26 mm., the tail grows as fast and no faster than the body, thereby maintaining a constant proportion. REMAINING PRopPoRTIONS.—As in the case of the tail, no definite correlation between variations in length of animal and variations in the remaining proportions was found. It seems unnecessary, therefore, to consider each in detail. Instead the correlation coefficients relative to each proportion, given below, show clearly the absence of definite correlations: Proportions Coefficients Interval from tail to ventral ganglion ___._.. r=—0.1403 +0.053 IDSA OLE MOSS Fi ae eee r=-+0.154 +0.096 Width of anterior fin - r= +0.0931 0.0656 Anterior fin to ventral ganglion ... r= +0.1485 +0.0647 Tenet hWotpOS ber ON efi ssc cnnseseeeececreeerenceeneers r= +0.0353 +0.0661 WWaldithito fap OS GOTT O MMU ese cetera nee ae meee menses r= +0.0679 +0.066 112 University of California Publications in Zoology (Vou. 11 To corroborate the evidence of the coefficients the average measurements of each proportion corresponding to each length of animal are here appended: INTERVAL FROM TAIL TO VENTRAL GANGLION 69.8 per cent for animals between 24 and 26 mm. 70.0 per cent for animals between 22 and 24mm. 69.8 per cent for animals between 20 and 22 mm. 70.4 per cent for animals between 18 and 20 mm. 69.5 per cent for animals between 16 and 18 mm. 69.8 per cent for animals between 14 and 16mm. 71.5 per cent for animals between 12 and 14mm. LENGTH OF ANTERIOR FIN 19.9 per cent for animals betwen 24 and 26 mm. 19.9 per cent for animals between 22 and 24mm. 19.8 per cent for animals between 20 and 22 mm. 0.0 per cent for animals between 18 and 20 mm. 9.8 per cent for animals between 16 and 18 mm. per cent for animals between 14 and 16mm. per cent for animals between 12 and 14mm, WIpTH oF ANTERIOR FIN .43 per cent for animals between 24 and 26 mm, 55 per cent for animals between 22 and 24mm. 7 per cent for animals between 20 and 22 mm. eo ip 2 2 2 2.45 per cent for animals between 18 and 20mm. 2.54 per cent for animals between 16 and 18mm. 2.21 per cent for animals between 14 and 16mm. 9 -12 per cent for animals between 12 and 14mm. INTERVAL FROM ANTERIOR FIN TO VENTRAL GANGLION .32 per cent for animals between 24 and 26mm, 59 per cent for animals between 22 and 24 mm. .61 per cent for animals between 20 and 22 mm. 58 per cent for animals between 16 and 18 mm. per cent for animals between 14 and 16mm. 1 1 1 1.39 per cent for animals between 18 and 20 mm. ] 1 1 per cent for animals between 12 and 14mm, LENGTH OF POSTERIOR FIN 24.2 per cent fo ranimals between 24 and 26 mm. 24.3 per cent for animals between 22 and 24mm. 24.4 per cent for animals between 20 and 22 mm. 5 per cent for animals between 18 and 20mm. per cent for animals between 16 and 18 mm. 24.2 per cent for animals between 14 and 16mm, 23.0 per cent for animals between 12 and 14mm. 1913] Michael: Sagitta californica from San Diego Region 113 WIDTH OF POSTERIOR FIN 3.92 per cent for animals between 2+ and 26mm. 3.94 per cent for animals between 22 and 24mm. 4.28 per cent for animals between 20 and 22 mm. 4.11 per cent for animals between 18 and 20 mm. 4.25 per cent for animals between 16 and 18 mm. 3.42 per cent for animals between 14 and 16mm, 3.50 per cent for animals between 12 and 14mm. In the case of the length of the posterior fin there is an indication of a possible negative correlation, the proportion diminishing at the rate of about 0.05 per cent for an increase of 1mm. in length of animal. However, as the average pro- portion, irrespective of the length, lies between 24.2 and 25.8 per cent, it is safe to conclude that the fin increases in length at approximately the same rate that the animal does. VARIATION AND CORRELATION IN NUMBER OF TEETH AND SEIZING JAWS The number of anterior and posterior teeth and seizing jaws is regarded by most investigators as of maximum significance in defining species of Sagitta. While I have suggested elsewhere (1911, p. 68), that ‘‘variations in number of both anterior and posterior teeth in many species is not referable to specific differ- ences, but probably to some distribution factor,’’ it is neverthe- less true that certain facts concerning their manner and rate of variation are of considerable specific importance, as will be seen in the following remarks. NuMBER OF ANTERIOR TEETH.—Variation in number of an- terior teeth is well revealed in the following histogram (text fig. 1), which shows that out of 191 tooth-rows counted in indi- viduals varying from 9.5 to 26 mm. in length none had less than 3 nor more than 7 teeth, while about 6 per cent had 3, 17 per cent 4, 32.5 per cent 5, 37 per cent 6, and 8 per cent 7. Now, while these frequencies, together with the rate of increase till the maximum is attained, the rate of decrease thereafter, the position of the maximum, and other features of the histogram are definitely characteristic of the population considered, their 114 University of Califormia Publications in Zoology (Vou. 11 value as specific constants is impaired, owing to the effect of variation in length of individual upon the number of teeth pos- sessed. In other words, if the number of teeth increase or deerease as the animal increases in length, it is evident that the 50 40 30 20 nature of the histogram will vary according to the number of specimens of any particular length constituting the population considered. It is necessary, therefore, to ascertain the relation between number of teeth and length of specimen. 1918] Michael: Sagitta californica from San Diego Region 115 TABLE 8 CORRELATION BETWEEN NUMBER OF ANTERIOR TEETH AND LENGTH OF ANIMAL Number Length of animal in mm. ton 12-14 14-16 16-18 18-20 20-22 22-24 24-26 Total 3 3 2 1 2 3 1 one 12 (100) = (33) (17) (17) (9) (1) 4 oe 2 5 8 8 8 2 33 (33) (83) (66) (24) (10) (4) 5 2 15 27 20 64 (17) (44) (32) (36) 6 2 8 40 25 (3) (33) (24) (48) (46) uf 7 8 15 (8) (15) Total 3 6 6 12 34 83 55 199 r= +0.609 +0.0300 Table 8 shows that the greater number of teeth is possessed only by the larger animals. Furthermore, when the upper ‘‘row’’ of the table is expressed in percentages of the total population of each ‘‘column’’ (see numbers in brackets), it is evident that the smaller number of teeth is associated with the shorter animals. Moreover, when all these percentages are examined the following facts relative to the number of teeth possessed by the majority of animals are apparent: Majority between have J2 and 14mm. 3 teeth 14 and 20mm. 4 teeth 20 and 22mm. 5 teeth 22 and 26mm. 6 teeth These facts show that the histogram (text fig. 1) is approxi- mately true only for animals over, but not under, 22mm. in length. NumsBer or Posterior TeEsptTH.—The number of posterior teeth varies from 4 to 16 in animals varying from 9.5 to 26 mm. in length. The accompanying histogram shows that no indi- 116 University of California Publications in Zoology \Vou- 11 vidual had 3, 5 or more than 16 teeth, while, out of 189 tooth- rows counted, about 1 per cent had 4, 2 per cent 6, 4 per cent 7, 5.5 per cent 8, 6.5 per cent 9, 19.5 per cent 10, 19.5 per cent 11, 17.5 per cent 12, 11 per cent 13, 9 per cent 14, 4 per cent 15, and less than 1 per cent 16. 30 20 —— 10 4 5 67 8 9 101112 13 141516 Here again the specific validity of this histogram depends upon to what extent the number of teeth is correlated with length of animal. Concerning this table 9 shows an even greater correlation than that displayed by the anterior teeth. This visual impression is corroborated by the coefficients, that relating to the anterior teeth being 0.609+ 0.0300 and that relating to the posterior teeth 0.751 + 0.021. Here it is perfectly evident that the smaller animals have the fewest and the larger animals 1913] Michael: Sagitta californica from San Diego Region 117 TABLE 9 CORRELATION BETWEEN LENGTH OF ANIMAL AND NUMBER OF POSTERIOR TEETH Number Length of animal in mm. teeth {2-14 14-16 16-18 18-20 20-22 22-24 24-26 Total 4-5 2 aes Stes ne meee sae cess 2 (67) 6-7 1 4 1 2 2 10 (33) (67) (17) (18) (7) 8-9 3) 8 5 9 27 (83) (73) (16) (11) 10-11 1 23 39 10 73 (9) (74) (48) (18) 12-13 2 sex : it 22 ou 56 (33) (3) (26) (55) 14-15 10 15 25 (12) 27) 16-17 2 2 (3) Total 3 6 6 11 31 82 56 195 r= 0.7506 +0.02109 the most teeth. Moreover when we consider the numbers in brackets the following facts are revealed: Majority of animals between have 12 and 14mm. 4-5 teeth 14 and 16mm. 6-7 teeth 16 and 20 mm. 8-9 teeth 20 and 24mm. 10-11 teeth 24 and 26 mm. 12-13 teeth These facts make it obvious that the histogram (text fig. 2) is approximately true only for animals between 20 and 24mm. in length, and even here the approximation is slight, for the rate of addition of teeth with an increasing length of animal is rapid. This histogram, then, can only be regarded as specifically con- stant when the population considered consists of a similar pro- portion of individuals of the various lengths to that upon which it is based. 118 University of California Publications in Zoology [Vou. 1 NUMBER OF SEIZING JAws.—These structures we found to vary from 6 to 10, the usual number being 8 or 9. Text figure 3 shows 50 40 30 20 10 (3 7 f& 8) We Fig. 3 in addition that out of 198 rows of jaws about 1 per cent had 6 jaws, while 13 per cent had 7, 46 per cent 8, 39 per cent 9, and 1 per cent 10. However table 10, as well as its correlation coefficient (r= 0.457 + 0.0372) shows that, while the length of animal and number of jaws are positively associated, the correlation is not so pronounced as in the case of anterior and posterior teeth. Still an examination of the numbers in brackets reveals the following facts: 1913] Michael: Sagitta californica from San Diego Region 119 Majority of animals between have 12 and 18 mm. 7 jaws 18 and 22 mm. 8 jaws 22 and 26mm. 8-9 jaws TABLE 10 CORRELATION BETWEEN JLENGTH OF ANIMAL AND NUMBER OF SEIZING JAWS Number Length of animal in mm. ° jaws 12-14 14-16 16-18 18-20 20-22 22-24 24-26 Total 6 1 1 2 (25) (17) 7 2 3 5 3} 9 5 1 26 (50) (59) (59) (25) 25) (6) (2) 8 il 2 9 20 38 28 98 (25) (33) (75) (56) (44) (50) 9 te 2 1 a2 7 43 25 78 (33) (17) (19) (50) (45) 10 2 2 (3) Total 4 6 6 12 36 86 56 206 r= 0.4566 +0.0372 SUMMARY We have discovered in this discussion of variation and correla- tion many facts of specific importance as follows: 1. In animals between 12 and 26 mm. in length, variation in the ratio between length of animal and leneth of tail, interval from tail to ventral ganglion, leneth and width of anterior fin, interval from anterior fin to ventral ganglion, and length and width of posterior fin—is approximately constant, irrespective of the length of animal. Of all proportional measurements these are, therefore, the safest for the identification of S. californica, and this is especially true of the proportional length of tail. 2. In animals between 12 and 26mm. the width of body, interval between anterior and posterior fins, interval from pos- terior fin to seminal vesicle, and length of ovary increase more rapidly than the animal increases in size, while the ventral ganglion increases less rapidly than the animal does. Therefore, the ratio between these various measurements and length of animal is of certain specific value only for animals of definite lengths. ty of California Publications in Zoology {Vou. 11 iwverst Un *‘[BULLUB JO YYSuaT [k10O} JO 4uUad Ted ur S}uUaMoINSvoOU [[V ST-OL OI-S OI-S OI-¢ C=O tae sak hn ee armas AIBAO FO Y4SUAT GE-GiG Gé-Gs &-G 4 b - a[OTSAA 03 UY IOTLO4SOg €9-6°¢ 8'9-L'¢ 8'9-L°S (Nite (AEF ie Eee UOTLSUBS [BI}JUVA FO YYHU'T 8'S-LF €S-G'P 8F-L§ STL Bebe iGo. at ie ake cane cece eaamare Apoq FO WAPTM 8 8 L L | a ane nag sg ae smel Sutztas JO Laquinyy IL-OL 6-8 6-8 1-9 Cope Wie ene 00} 1or1eysod Fo 1aquinyy ig £ P F g - Yoo} 1olloyuB FO 1aquINnNy [eulue JO YASUE, Uo yUopuodap soT4ysItoqoRIeYO “g ats c-€ Cae Gat é uy ioreysod Fo YIpPTAy 96-6 9-6 93-6 GZ Sy dee a ee are uy tordeysod yo yysuery 6-L 6-9 6-9 b ee ee ee ug 1or1toysod 03 1olleyuy 2-1 2-1 rei o-1 Cale 9 Matas UOT[SUBS [VIJUOA 04 UY LOLIOJUW OS ZaE OE-LT Oe Seal OE-LT {SY ese 7 | NNN ate BR hoa ca ncee 7 uy 1OTlozMe FO YUFPTAL 13-61 1g-6L 16-61 16-61 é uy IOl1e}UB FO Y45UeTT TL-69 11-69 11-69 11-69 CAS OM As = Seacrest incre aaee UOTLHUBS [BIZUAA 0} [TRY, 66-13 83-96 83-96 83-93 OcaOG Merec sages sae crcraee acerca [rez FO WSU] GE—-06 O0G-8T 8L-9L 9I-F1 JiR Raly, eee “UU UE speuruR JO Y4ouerT [eurue FO YISue_ Jo oATyodsadit yURsUOD SoIstIoJOBILYY) “W ¥dN08)-HLONAT HOVG, NI SIVWINY dO ALIMOLVYIY OL TALLVTAY SOMMSTYALOVUVH() FO AYVWWOG 120 Tl WIaVL 121 go Region eC fornica from San Di Sagitta cali Michael 1913] 9S Fa'S L0°S COP CIs LOL TOL GL GL 9E¢ 96°E soO'e 686 89% 68 0'8 OL SL oL 6e'S T¥'S 8g FL'9 ee9 668 FOE 8aF IVF COF BEG oS FFG GSS 8°56 6eL 6ST I9'T 6ET 8oL EG cose LUG CFG PSG O6L 66L S'6L 0°06 S'6L 8°69 0'0L 8°69 VOL £69 9°16 UL3 OLE GLE 8 L6 96-¥6 $6-GG 66-06 O6-8T 8L-9L ‘WulUB Jo YISua, [B}0} Jo yusd aed ul uasrs suoysodoag , é é : Apoq JO U3PtTA\ Cy G7 nimnncacnas aac s a ccoae nos taeonaoe AIVAO JO YABuarT O0'F Ga ir ae a a[PIsaA 04 UY LOlI04SOq 88 QO TI gEMN apraita Siac eas uy Lo11a4ysod 03 1o1me4yay 9L'9 OR Fee UOT[HUBS [RIYUAA JO YYZuUery quspuedap sarjstioqjoneyy “gq oFe OSes Uy Tor1a4sod Jo APLA\ BPS ONG Pare nate oeroces aceaes uy torteysod yo yySuery Ga yee 9 aateeeasce UOT[LHUBS [BIZUGA OF UY JOTIAZUY 1e%G GUS “UY IOTI9}Ue JO YIPTM Z'0Z CUT ~ UY LOlleyUR JO Y4SUarT 8°69 (om Wi} WOT[HURS [BIZWAA 04 [IBI, GLE ORB Gj. ERE irate rec a & [fey FO [4SuUeryT OI-FI PISS ca esciecstsseesés “WU UL SspBUTUe JO YYSuerL [BULLUe FO YASuo, JO CArjpodsortt yuRysuod soysiojoweyy “y +d204Y)-HLINAT HOV do STIVWINY NI SNOILYOdON AWYIAWY FHL OL FAAMLVIAY SOILSIMALOVYVHD JO AYVINWOG Gl ATAV EL 122 University of California Publications in Zoology [Vou 11 3. The number of anterior and posterior teeth and seizing jaws increases as the animal grows larger, the rate of increase being greatest in posterior teeth and smallest in seizing jaws. Therefore, the specific value in number of these structures depends not only on the extremes of variation but, quite as definitely, on the amount of variation in the rates of icrease. 4. The maximum number of animals whose lengths vary within 1mm. from 13, 15, 17, 19, 21, 23 and 25mm. have the characteristics summed up in table 11. 5. The average proportions of the various regions of the body relative to animals varying between 12 and 14, 14 and 16, 16 and 18, 18 and 20, 20 and 22, 22 and 24, and 24 and 26 mm., are summed up in table 12. It is needless to say that, in tables 11 and 12, the figures are not very reliable in the case of animals under 18mm. in length because of the small number considered. For the others, how- ever, the figures ought to hold good within a small range of variation if determined on the basis of a moderately large number of specimens. Furthermore, if S. californica should be discovered elsewhere than in California waters, these tables will furnish means for ascertaining the direction and degree of variation due to differences in locality. DISTRIBUTION Altogether 236 specimens were obtained, of which one was taken in a Nansen closing net haul (no. 2858) made from 150 to 100 fathoms, two in a similar haul (no. 2840) made from 10 to 5 fathoms, and the remainder from the surface. None were obtained prior to October 24, 1911, nor, so far as the hauls have been examined, since October 28, 1911. Furthermore, of the twenty-one surface hauls made, all but two obtained the species. Now the same localities from which this species was obtained were thoroughly investigated between the surface and 75 fathoms during every month of 1911, except September, and it seems probable that S. californica was not present prior to August 11th nor after November 27th, the former being the last date ot hauling previous to October 24th, and the latter being the first 1913] Michael: Sagitta californica from San Diego Region 123 date of hauling after October 28th. The exact data concerning the October surface hauls are given in the accompanying table. TABLE 13 Data CONCERNING THE SURFACE CatcuEs or Sagitta californica.* Haul Tempera- Number of number Net Date Time Station ture, C. specimens 2785 000 Oct. 24 8:00— 8:45 a.m. B 19.15 7 2800 000 Oct. 24 10:20-10:55 a.m. B 19.3 11 2803 000 Oct. 24 11:10-12:30 a.m. B 19.3 42 2821 000 Oct. 24 2:10-— 3:07 p.m. B 19.4 {Tf 2826 000 Oct. 25 7:10— 8:10 a.m. A 19.2 3 2829 000 Oct. 25 8:32— 9:40 a.m. A 19.5 7 2842 000 Oct. 25 9:50-10:50 a.m. A 20.1 1 2855 000 Oct. 25 11:00-12:00 a.m. A 20.2 2 2861 000 Oct. 25 12:10-12:45 p.m. A 2 19 2864 000 Oct. 25 1:00— 1:45 p.m. A 19.9 6 2871 000 Oct. 26 7:50— 8:50 a.m. A 19.2 5 2877 000 Oct. 26 9:00-10:20 a.m. A 19.1 9 2883 000 Oct. 26 12:00-12:50 p.m. A 19.4 1 2894 000 Oct. 27 7:00— 7:40 a.m. B 18.6 18 2906 000 Oct. 27 12:00-12:30 p.m. B 19.2 14 2909 000 Oct. 27 1:05— 1:55 p.m. B ? 2 2917 000 Oct. 28 9:25— 9:45 a.m. A 18.8 4 2921 000 Oct. 28 9:50-10:10 a.m. A ? 4 2924 000 Oct. 28 10:20-10:45 a.m. A ? 1 * Station A is located at 32° 2277 N, 117° 19/2 W on a line extending WSW of South Coronado Island at a point approximately three and one-half miles from the island, where the water is 350 fathoms in depth. Station B is located at 32° 2274 N, 117° 21’2 W on the same line approximately two miles farther seaward, where the water is 700 fathoms in depth. Owing to the small number of specimens obtained and owing to the fact that their capture was limited to four days of October, 1911, very little regarding their manner of distribution is deter- minable. However, table 13 reveals one interesting fact, namely, that the species was more abundant at station B than at station A, i.e., at the location farthest from land. Altogether 171 speci- mens were obtained from station B and 62 from station A, or an average of 22 per hour at B and 7 per hour at A. Furthermore this relation holds when the corresponding times of day are compared, as in table 14. 124 University of California Publications in Zoology (Vou. 11 TABLE 14 SHOWING RELATIVE ABUNDANCE OF SPECIES aT A AND B Station A Station B Time of day Specimens al - Spectuensi Hauls Hours Total Per hour Hauls Hours Total Per hour 7tol0am 5 4,8 28 6 3 2.5 25 10 10 to 12:30 a.m. 5 3.2 9 3 4 3.6 67 19 12:30 to 3 p.m. 2 103) 25 19 2 1.9 79 42 Should the reader exhaustively analyze table 13 with respect to this difference between the two locations he would realize that this appearance is probably not due to chance but to a definite correlation. It is, however, another matter to discover its significance. If this appearance be due to the distance from land then it would be legitimate to conclude that S. californica is mainly an oceani¢ species. On the other hand, S. enflata accom- panied S. californica in nearly every haul and, as pointed out elsewhere (1911, p. 156), this may mean the occurrence of a tropical current, in which event we should expect the species to occur more abundantly nearer the current and therefore possibly farther from the coast. Had the investigations been extended over ten or fifteen stations at increasing distances from land some clue to the significance of this correlation would doubtless have been discovered, but as the matter now stands it seems un- justifiable to do more than point out these two possibilities. Scripps Institution for Biological Research of the University of California, La Jolla, California. Transmitted September 1, 1912. 1913] Michael: Sagitta californica from San Diego Region 125 LITERATURE CITED MIcHAEL, E. L. 1911. Classification and vertical distribution of the Chaetognatha of the San Diego region, including redeseriptions of some. doubt- ful species of the group. Univ. Calif. Publ. Zool., 8, 21-186, pls. 1-8. Pearl, R. 1911. Biometrie ideas and methods in biology, their significance and limitations. Scientia, 10, 101-119. von Riprer-ZAnony, R. 1908. Chatognathen. Ber. Comm. Enforsch. 6stl. Mittelmeer, Zool. Ergeben, 14, 18 pp. 1 Taf. 1910. Die Chaitognathen. Fauna Arctica, 5, 251-288, Taf. 5. 1911. Revision der Chatognathen. Deutsche Stidpolar Exped. 1901- 1903, Bd. 13, Zool. 5, 71 pp., figg. im text. EXPLANATION OF PLATE 2 All figures drawn with the camera lucida. Fig. 1. Ventral view of Sagitta californica. X 10. g. 2. Vestibular ridge of Sagitta californica. X 335. 3. Anterior teeth of Sagitta californica. X 440. Fig. 4. Seizing jaw of Sagitta Californica. X 1300. ABBREVIATIONS ant. f.—anterior fin. post. f.—posterior fin. col.—collarette. seiz. j.—seizing jaws. int.—intestine. sem. ves.—seminal vesicle. ov.—ovary. t. f.—tail fin. [126] UNIV. CALIF. PUBL. ZOOL. VOL. 11 [MICHAEL] PLATE 2 POSE ite é SS SS sem. ves. Pet pf E.L.M., del. ad nat. Lith. Gottschalk, S.F. - r = * Se < S i% ey - ~ - . vA UNIVERSITY OF CALIFORNIA PUBLICATIONS ~ Note.—The University of California Publications are offered in exchange for the publi- © cations of learned societies and institutions, universities and libraries, Complete lists of = all the publications of the University will be sent upon request. For sample copies, lists of publications or other information, address the Manager of the University Press, Berkeley, California, U. S. A. All matter sent in exchange should be addressed to The Exchange Department, University Library, Berkeley, California, U. iy ees OTTO HARRASSOWITZ, g R. FRIEDLAENDER & SOHN, LEIPZIG. BERLIN. cs Agent for the series in American Arch- Agent for the series in American Arch- _ acology and Ethnology, Classical Philology, aeology and Ethnology, Botany, Geology, Education, Modern Philology, Philosophy, Geography, Mathematics, Pathology, Physi- Psychology, History. ology, Zoology, and Memoirs. z ZOOLOGY.—W. E. Ritter and C. 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McClen- — ; don, - Pp. 33-64, plates 1-6. «July, 1909. -222..22-0. nce BS Ue ee 4, (XXVI) Halocynthia johnsom n.sp.; A comprehensive inquiry as to SSS the extent of law and order that prevails in a single animal species, — 2 =- = = <7 = == + — = 55 5 0 45 5 10 35 5 20 40 10 10 30 10 20 41 uf aly 45 bye 9) 55 0 5 35 10 15 35 5 20 55 5 0 45 Gy alt) 52 3 5 50 5 5 30 15 15 35 0 25 35 20 5 40.4 8.6 11 58 0 2 50 0 10 40 10 10 40 10 10 10 10 40 39.6 6 14.4 55 5 0 20. 10 30 50 5 5 20 30 10 40 5 15 3 LL 48 0 12 55 0 5 40 5 15 45 15 0 40 10 10 45.6 6 8.4 10 5 45 50 10 0 50 10 0 25 0 385 50 0 10 37 5 18 380 25 5 45 0 15 55 5 0 50 10 0 20 25 15 40 13 i 55 5 0 50 5 5 55 5 0 45 10 5 25 20° 15 46 9 5 57 3 0 55 5 5 50 10 0 30 25 5 30 20 10 44.4126 3 45 6) il) 35 5 20 55 5 0 40 15 5 55 5 0 46 7 7 50 5 5 50 5 5 45 15 0 35 10 15 50 10 0 46 9 5 Observation of the preceding table indicates the strongly positive character of the rheotaxis of Dina. The animal re- sponds by swimming for the greater part of the time vigorously against the current. This positive rheotaxis is probably of con- siderable significance to the animal. The usual habit of Dina is quiet ponds, or near the edge of fresh-water lakes under stones. A positive rheotaxis would tend to keep the animals in such localities where they bred. Young individuals, one-eighth the size of the adults, showed responses as decided as the older ones. No experiments were conducted to determine the rheotactic responses of Glossiphonia stagnalis, since in this form there is no swimming reaction and the principal effect of the current would be to make the animal hug the bottom of the dish. 1913] Gee: Behavior of Leeches 229 7. CHEMOTACTIC RESPONSES In the experiments with chemicals, the tests were all made with a half dozen individuals for each chemical, the leech being placed in a separate glass dish. Before a different strength of the same chemical was used the leech was placed for a few min- utes in clean water. The substances were allowed to diffuse into the water from a capillary pipette, the rate being so regulated as not to produce a response from the current. This can be done by gauging the size of the opening of the delicate capillary tube. Nitric acid, acetic acid, sodium chloride, copper sulphate, and cane sugar were the substances used. All strengths of nitric acid of a greater intensity than 1/80 per cent produced a nega- tive response. To dilutions less than this, an indifferent reaction was observed. Acetic acid revealed a similar condition at 1/30 per cent; sodium chloride at 1/5 per cent; copper sulphate at 1/320 per cent. Copper sulphate even in small quantities pro- duced a very marked effect on the leech, producing swimming and a long continued activity. Cane sugar in an intensity of 5 per cent produced no response that could be interpreted as either negative or accentuation of positive reaction. The response to the injurious chemicals localized in this way is as decided as in the ease of localized contact stimulus. As would be conjectured, the animal shows a directly positive reaction to diffusing snail juices. The nature of this has already been described in the discussion of the feeding of leeches. Best results are secured when the food juices are fairly strong in concentration, and placed relatively close to the anterior end of the body. The significance of these results lies in the fact that the animals respond negatively to chemicals of an injurious nature in just as adaptive a manner as to contact stimuli, turning sharply away, and if the stimulus is a strong one, swimming rapidly out of the unfavorable environment. To chemical stimuli of such a nature as those found in its food material, the Dina re- sponds in a positive manner. 230 University of California Publications in Zoology [Vou. 11 8. REeacrions To GRAVITY In collecting material for this work, it was observed that the most successful place for dredging for the Dinas was on the bottom of the pond. When brought into the laboratory, and placed in aquaria, the leeches crawl around on the bottom of the jar or rest quietly in masses underneath stones. It is rather rare that a specimen of Dina microstoma is to be seen on the sides of the aquarium ; however, this is not true with Glossiphonia, since when the influence of lght is removed these forms fre- quently collect in groups along the sides of the jar. When a Glossiphonia is placed on a vertical glass plate, however, it will usually incline downwards and crawl to the bottom of the dish. A Dina placed in a glass tube bent at right angles, and sub- merged in the water, will in the majority of cases come to rest in the horizontal portion. These observations lead one to the conclusion that this species is normally positively geotactie. Under certain conditions, there seems to be a tendency towards the reversal of this reaction. In his work on the leeches of Japan, Whitman (1886) says: ‘‘I have never seen the land leech of Japan on trees, and I believe it keeps itself habitually on the ground, or in the moss, or under damp leaves and loose rubbish. When awakened by the footsteps of man or beast it quickly appears on the surface, and frequently ascends low plants and oceasionally perhaps trees in search of the intruder.”’ When stimulating a specimen of Dina microstoma to induce fatigue it was observed that there was manifested more than a dozen times the attempt on the part of the animal to crawl out of the dish. This suggested that what appeared to be a reversed geotaxis might be a tendeney for the animal to crawl out of an environment unfavorable to it. So jars filled with, and inverted in, water boiled for thirty minutes and cooled in a corked flask were supplied with a number of leeches. Increase of undulatory movements was observed, but the reduction of oxygen seemed to have no effect on the geotaxis of the animal. Not so with mechanical shocks, such as jarring. Dozens of times it was noticed in the aquaria on my laboratory table that when these were shaken by a sudden jolting of the table large 1913] Gee: Behavior of Leeches 231 numbers of the Dina would begin to crawl up the sides and corners of the dish, squirming and twisting over one another. The same result was secured in jars placed on a springy board and jarred several times repeatedly. This tendeney does not persist for any great length of time; for the animals release their hold in a few minutes and either drop to the bottom of the dish to crawl around or swim about as is their usual reaction when in a fairly active condition. A second heavy jar or series of jars produces nothing like so marked an effect, the animal apparently regaining its normal equilibrium rather quickly. When a half dozen specimens were placed in water of 36° C they became exceedingly active. They would settle to the bottom of the dish often, and, executing random movements, would either move off rapidly by looping or giving the swimming response. Even water cooled to several degrees lower gave no evidence of the tendeney to produce reversal of geotactic response. The effect of the heat seemed to find expression in the increased activity of the individual, and the accompanying excess of random movements. It is rather interesting that in two forms as widely separated in habits as are the land leeches of Japan and the Dina of this country, a purely aquatic form, there should be the same ten- dencies of behavior in this regard, even though the tendeney to reversal is not nearly so pronounced in the nephelid as Whitman has described it for the land form. The blood-leeches seem to show an indifferent geotactie re- sponse when kept in aquaria. A dozen specimens kept under observation for several months in the laboratory were noted to lodge themselves out of the water almost as often as they remained immersed in it. When out of the water they suspend themselves by the two suckers, either stretching in a straight or curved position along the sides of the dish, draping themselves in a not ungraceful festoon from the under surface of the cover of the jar. 9. INFLUENCE OF HEAT No attempt was made to determine the optimum temperature conditions of the leeches. In Dina microstoma temperatures as low as 10° C, when continued for several hours lower decidedly 232 University of California Publications in Zoology (Vou. 11 the responsiveness of the animal. To a localized application, by means of a capillary glass rod, of water heated to 70° C, a negative response with an accentuation of random movements is produced. Toa higher temperature, 90°—95° C, a sharp negative response accompanied by the swimming reaction is the usual habit. As already stated, the effect of a uniform temperature of 36° C is to produce a markedly increased activity of the animals subjected to it. When currents of heated water were induced in a long, shallow dish by immersing a flask of water heated to 90° C, a tendency was observed for the animals to collect in the regions of lower temperature, thus seeking as nearly as was possible their optimum temperature conditions. 10. THIGMOTAXIS The strongly positive thigmotactie propensities of the leech have already been mentioned as a factor in the formation of collections. Positive thigmotaxis is still further evidenced in the large number of individuals that will find shelter underneath a small stone. When placed in an aquarium with mud and decaying vegetation in the bottom, Dina is often observed with two-thirds of the posterior part of the body buried among this debris, the anterior end projecting and exercising undulatory movements. To a localized contact stimulus applied to the anterior end the usual response is a turn in the direction opposite to that of the stimulus. This varies rather widel:y under successive stimu- lation and other factors discussed in a later section of this paper. There is considerably less variability in response to stimulation of the posterior end. In the posterior end stimulation, the re- sponse is either by ‘‘looping’’ or by “‘swimming,’’ just which response is given depending upon several factors discussed in the second portion of this paper. 11. Asmiry TO WITHSTAND DESICCATION In most localities it would be comparatively rare that the species Dina microstoma or Glossiphonia stagnalis would have to undergo desiccation in its native habitat, and it is very fortunate for the species that this is true. Within a relatively few minutes 1913] Gee: Behavior of Leeches 233 after having escaped from the aquarium Dina will dry to such a state that it is beyond recovery upon being placed in the water. There seems to be no characteristi¢ posture assumed in the drying up of this species. The body is twisted into various shapes as the final result of the desiccation, the most common one having the anterior and posterior tips drawn in towards the center of a semicireular arch formed by the body. During the process of drying the nephelid is often exceedingly active, the contraction of the muscles of the body, affeeted by the drying, forcing the animal to assume widely different attitudes successively. Frequently when removed from the water, Glossiphonia will roll itself up in the ‘‘pill bug’’ fashion, and consequently is able to withstand considerably more exposure to drying influences than Dina. However, the ability to withstand desiccation is not a well developed feature of the repertoire of either of these two genera. VI. SPECIAL FEATURES OF BEHAVIOR IN LEECHES 1. MopiricaTions OF BEHAVIOR DuRING THE BREEDING SEASON Unfortunately, among the hundreds of Dina microstoma kept under constant observation in aquaria, no egg cocoons or other signs of breeding were observed. The only recorded observations on the breeding behavior of the nephelid leeches that I have been able to find are those of Iijima (1882). This worker noted what he construed as abnormal copulation, but ‘which was later inter- preted by Whitman (1891) as hypodermic impregnation through the ageney of spermatophores. Quoting from Whitman: “‘ Al- though it is well known that spermatophores are of general occurrence among the invertebrates, and even among many verte- brates, the assertion that, as a perfectly regular and normal affair, in animals as highly organized as the leeches, they repre- sent an injecting apparatus by means of which the spermatic elements of one individual are forced through the body wall of another at any point whatsoever, may appear almost incredible, even when supported by direct observation many times repeated 234 University of California Publications in Zoology (Vou. 11 on different species. That such is certainly the case, however, is very easily demonstrated and one can verify it as often as he hikes on almost any species of Clepsine that happens to be acces- sible.’’ Houghton (1863) early recorded the fact that some of the ‘ Glossiphonidae possess the rudiments of an ‘‘ineubating’’ and ““parental’’ instinct. Castle (1900) records several observations in regard to the egg-laying process in the species Glossiphonia stagnalis. In the vicinity of Cambridge, Massachusetts, he notes the egg-laying period as being chiefly in the months of April and May, though extending to as late as September. The eggs are attached in groups to the under surface of the body. Each group is enclosed in a delicate transparent sae, these sacs being arranged in two longitudinal rows placed close together. The ege-laying occurs at night in animals kept in aquaria and was not observed. The number of eggs laid appears to depend upon the size of the animal, varying from sixteen to forty-five in number, with an average record of thirty-one. Castle (1900) says with regard to the mode of feeundation in Glossiphonia stagnalis: ‘‘ Whitman (1891) has shown that in the ease of G. parasitica (Clepsine plana) the contents of the spermatophore pass through the integument into the body cavity, and that impregnation probably occurs while the egg is still in the ovary. A similar process doubtless occurs in the case of Glossiphonia stagnalis.’’ Moltschanov (1911) has recently given his observations on some features of the breeding behavior of certain European species of the genera Glossiphonia and Hemiclepsis. He finds upon sectioning the body of adults of these two genera that there are modified epidermal cells, which in their arrangement permit of the more ready and effective attachment of the suckers of their young. He also suggests as probable that the young derive their sustenance for the first third of their growth period from the secretions of the ventral secretory cells of the adult body. As evidence of this he records that the young can live only a short time when removed from the parent body. Bolsius (1911) mainly confirms the results of Moltschanoy. He believes, how- ever, that the mortality among the young as the result of removal 1913] Gee: Behavior of Leeches 235 from the body is due to insufficient aeration. The parent with its young attached frequently performs undulatory movements, which provide the young animals with the necessary oxygen supply. Castle (1900) has pointed out that in Glossiphonia stagnalis “the time of egg-laying, as well as of spermatophore formation, depends upon the warming of the water in the spring. One can hasten both processes by bringing the animals for a few days into a heated room.’’ My experience in Berkeley has been much the same. In early December, on January 2, and February 18 several dozens of specimens of Glossiphonia stagnalis were col- lected from Stow Lake, Golden Gate Park, San Francisco, and placed in aquaria in the laboratory. These specimens were ex- amined carefully when collected, and were found to carry no eggs or young. After having been in the laboratory for several days the leeches were again examined, and a few of them col- lected at each of these dates were observed to have eggs attached to their ventral surfaces. Specimens collected in the months from August to the middle of November were found many of them to have eggs or young attached. This would indicate that the lower temperatures cause the cessation of breeding. A some- what extensive breeding season would seem necessary to account for the literal millions of specimens of this species inhabiting the stones along the edges of this lake, in the shallower water. The fact that a form as low in the seale of life as the leech is to be found carrying eggs in the same manner as does Glossi- phonia naturally arouses the question as to the possible occur- rence of a ‘‘ parental instinct’’ in its simpler expressions. Several individuals of Glossiphonia were secured carrying eggs attached to the ventral surface. These eggs were contained in sacs, as described by Castle (1900), some four to six usually, and totaling a varying number from twenty-one to thirty, with sometimes a few more. With a blunt-pointed needle these sacs of eggs were removed, and immediately placed, together with the individual from which they were taken, in a small glass dish 3 em. in diam- eter. Careful count was made of the eggs separated in order to prevent any error which might arise through the laying of more eggs. When coming in contact directly with the eggs the 236 University of California Publications in Zoology [Vou. 11 leech crawled by them or over them with entire disregard. In eases where the parent was left in the dish with the egos for sixteen hours, and in one ease for four days, not a single egg was picked up or the mass of eggs brooded over, even when placed in the least lighted portion of the dish. The stimulus of the removal of the eggs caused at first a marked activity, but later the animal was restored to the normal rate of activity, and even then the eggs were as markedly disregarded as if they had been debris in the dish. Thus the entire neglect of its eggs on the part of the parent was several times proved distinctly. In other specimens with eggs attached, a part of the mass was loosened up so that a few of the eggs dropped out and many of them were hanging to the body. The only response was a more contracted condition of the body in the region where the eggs were carried. In this case there was also an acceleration of the activity due to the stimulus of the removal of the eggs. The local stimulation of the part of the body from which the eggs were partially removed may satisfactorily explain the local contraction of the body at this point. Although observed at intervals of a few minutes for four hours, no reactions other than this local contraction and initial acceleration of movement were observed, and these conditions became normal within a half hour after the experiment was begun. The carriage of the eggs is to be viewed as a more or less forced condition on the part of Glossiphonia stagnalis, due to the fact that they are enclosed in saes attached to the body. When the eggs are hatched the young are carried in much the same place as the eggs. These young individuals are strongly attached by the posterior sucker of their bodies. Removing the young produces, as in the ease of the removal of the eggs, an active condition of the animal which seems to be entirely due to the mechanical stimulation of removal, since the specimens become normal in their responses after a period of a few minutes. Into a small dish 3 em. in diameter were placed an adult Glossiphonia and its detached young. The small leeches are very quick to seize the opportunity of attachment, and often cling to various parts of the body of the parent species. Upon their attaching themselves to the dorsal surface of the body, particu- 1913] Gee: Behavior of Leeches 237 larly the anterior end, the parent was observed many times twisting itself almost into knots in order to get rid of the young, sometimes very successfully doing so. However, three hours later all of the young were securely attached by their posterior suckers to the ventral surface of the body of the parent. This was undoubtedly accomplished by successive attachment on the part of the young and removal of them by the efforts of the parent, until as its body passed over the young these attached themselves finally in the proper manner and could not be successfully dis- lodged by the parent form. Thirteen young, the burden of a single individual, were sepa- rated from their parent and in the dish with them was placed an individual of the same species, which, however, when collected, was found to be carrying no young. The small leeches attached themselves to this adult quite as readily as to their parent, and upon becoming attached to the foster-parent remained in this position for four days, as long as the experiment was continued. This shows thoroughly that there seems to be present no attraction to the mother, but that any adult specimen, so long as it is a Glossiphonia stagnalis, serves to afford as effective and _ satis- factory a lodging place as any other of at least the same species. In order to test this point further, thirty specimens in the aquarium were examined to see how many carried young. Out of this number, thirteen carried young, seventeen being without such a burden. The number of young carried by the different individuals varied from as few as one to as many as twenty-five. Of the thirteen carrying young, two were observed carrying one, and as many carrying three and four respectively. The others earried a larger number. These results indicate no choice of parents within the limit of the species, nor any other alternative on the part of the adult than to carry the young when they become successfully attached to the ventral surface. I have several times observed fair sized young attached to the ventral surface of adults carrying eggs some stages before hatching. Oftentimes the load of a single individual is made up of young of varying sizes, another piece of corroborative testimony. This strong positive thigmotaxis of the young is indeed a very adaptive trait, and the persistency with which they will 238 University of California Publications in Zoology (Vou. 11 repeatedly attach themselves is also a feature in their favor. In the absence of an adult form, the young collect in groups on the bottom of the aquarium just as do the older specimens. In the young of Hemiclepsis occidentalis this reaction is Just as pro- nounced as in those of Glossiphonia stagnalis, though I have not collected the adults of this Hemiclepsis in groups such as Glossi- phonia forms. It may be, however, that where they occur abun- dantly the formation of collections may also take place in this species. In one dish, forty-three young of Hemuiclepsis were placed, and these formed two groups which were not dispersed during the two weeks in which the experiment was continued. Any disturbance of the dish, such as jarring or blowing on the surface of the water, caused a vigorous waving of the anterior end of their bodies, as if they were searching for the disturbing factor. A large specimen of Hemiclepsis occidentalis carrying the forty-three young above mentioned was first separated from its young. In the dish with these young of Hemiclepsis was placed an adult Gl. stagnalis which formerly had been carrying young, but from which this encumbrance had been removed sufficiently long for the animal again to become normal in its movements. After remaining in the dish eighteen hours with the young, these several times being aroused to activity, this adult Glossiphonia did not carry a single one of the young Hemiclepsis. The orig- inal parent was now placed in the dish, and within five minutes two of the young had found their nestling place on the parent Hemiclepsis. Twenty minutes later a total of eight was found attached, the others having become massed along the sides of the dish. The movements of the larger species, adult as well as young, are somewhat slower than those of Glossiphonia, and it was thought that here might be a possible explanation of the differ- ence in the behavior of the young towards adults of two different species. Two specimens of Glossiphonia were decapitated, and necessarily, after a short time, little movement resulted. Al- though the young of the larger species were kept moving actively about the decapitated specimens, none attached itself to the body of these leeches of a different genus. 1913 | Gee: Behavior of Leeches 239 Next, the Hemiclepsis was placed in the dish with fifteen voung of the smaller and more active forms. After four days of this combination had elapsed, none of the young of Glossi- phonia showed any more fondness for the foreign foster-parent, as evidenced by permanent attachment, than its young had evi- denced for Glossiphonia. While none of the young of Hemiclepsis were observed to attach themselves to the adult Glossiphonia, the reverse condition was noted in a few eases. The young of the glossiphonid in crawling about in the dish would come in contact with the body of Hemiclepsis and would sometimes attach themselves to the dorsal surface. The adult specimen would under such a condition soon come to rest, the lateral margins of the body closely pressed against the bottom of the dish. In this way the young glossiphonids were prevented from attaching themselves for permanent lodgment, and would soon leave the body, and finally join the collection already made by the other young in the angles of the dish. Thus on the part of the parent forms no evidence of a parental instinct seemed present. There is recorded at least one species of Glossiphonia (Bolsius, 1911; Houghton, 1863) that seems to lay its eggs on some foreign object, and to remain over them after deposition until they are hatched. Gibbs (1897-1899) notes a similar behavior in the skate-leech, Pontobdella muricata. Whit- man (1878) says of Clepsine marginata: ‘‘The worm remains over the eges, for the purpose of protection only, till they hatch. The young, soon after exclusion, become fixed to the ventral side of the parent, and are thus borne until they are fully developed and able to provide for themselves.”’ In these cases, there does seem evidence for at least a rudi- mentary ‘‘brooding’’ or “‘ineubating’’ instinet. Unfortunately, none of these forms was available for experiments in this con- 9 nection. The chief eagerness for protection in Glossiphonia stag- nalis and Hemiclepsis occidentalis was manifested on the part of the young in the form of strongly positive thigmotactie reactions. The discrimination on the part of the young of Hemiclepsis for the parent form of their own species as contrasted with that of a related one is very probably much akin to the recognition of the adult forms for their own species in the process of spermato- phore deposition. 240 University of California Publications in Zoology [Vou. 11 2. DiurNAL RHyYTHMICAL BEHAVIOR The leeches experimented with in this work, as has been stated, are under normal conditions negatively phototactic. This is well evidenced by the fact that they persistently remain under- neath stones or among the debris of their environment during the day. Upon coming into the laboratory at night I observed many times that the leeches of both of the genera Dina and Glossiphonia were crawling actively about in the aquaria. In many instances the glossiphonids were observed by the hundreds crawling about on the sides of the dish, exercising undulatory movements, or sometimes moving along underneath the surface film much in the same manner as does the fresh-water planarian. Dina was usually to be found erawling about on the bottom of the dish. The diurnal rhythm appeared so pronounced in Glossiphonia stagnalis that it was thought worth while to test its possible per- sistence under uniform and constant conditions of illumination. When a jar containing several dozens of adults was placed under constant light in a dark room it was found that the leeches re- mained underneath the stones in the dish for as long as a week, the length of the experiment. Observations were made daily at intervals of a few hours from eight o’clock in the morning to a varying period of nine to eleven in the evening, and it was very rarely that a single specimen was found active in the dish. The jars of specimens kept under constant darkness showed, within a half hour after being placed in the dark room, a very noticeable activity and movement of many of the leeches to the sides of the dish. This response was found to continue for several days, not any of the leeches, however, continuing active during the whole of this period. These results seem to indicate that the diurnal rhythm in these forms is very largely the result of the direct action of light. However, certain other factors must play an accessory role in the production of periods of rest and activity. Thus fatigue as the result of continued activity would cause the animal to come to rest in conditions of either darkness or light. Satiety would have much the same effect, as is shown in experiments 1913] Gee: Behavior of Leeches 241 discussed in a later portion of this paper. On the other hand. hunger, by producing a condition of increased irritability in the organism, would tend within certain limits to cause activity resulting in what might be called a search for food. 3. BEHAVIOR OF THE YOUNG LEECHES The reactions of the young of Hemiclepsis and Glossiphonia when only about two millimeters in length are, with few excep- tions, essentially the same as those of the adult specimens. The normal activity of the young is marked by a somewhat greater irritability than is the case in the older forms. This fact is very clearly indicated in the excess of random movements in the process of locomotion of the young. The response given by the young to localized contact stimuli are the same as those described for the adult forms in a previous portion of this paper. The positive thigmotaxis, so well developed in the adult leeches, is even more pronounced in the young individuals of the two genera studied. This is shown to a marked degree in the young of Hemiclepsis. It was unfortunate that only one specimen of this species carrying young could be secured; how- ever, the forty-three composing its burden provided a sufficient number to permit of the observation of many features of their behavior. When removed from the body of the parent, and placed in a separate dish, the young would usually cluster in one or two groups, their posterior suckers attached side by side to the bottom of the dish. In such a position the young were al- lowed to remain for a couple of weeks. They were observed rather frequently during the day, and sometimes in the evenings. So fer as noted, scarcely a single specimen released its hold on the substratum. The slightest jar of the table would set them to waving their anterior ends about in the dish, as if searching for the intruding factor. Soon, however, they would again settle down to a comfortable repose. This grouping, in so far as rela- tive position of the bodies of the young to each other is con- cerned, is practically the same as that which is found among the young while attached to the under surface of the body of the parent. 242 University of California Publications in Zoology (Vou. 11 Tn the young of this same species, the deceptive quiet reaction was secured upon contact stimulation just as in the case of the older specimen discussed in a preceding section of this paper. One young specimen was observed to remain perfectly quiet for as long as eight minutes after being lightly stimulated with a fine bristle attached to a wooden handle. Further light stimu- lation of a young leech, when placed in this condition of deceptive quiet, does not produce more than a local contraction, in most cases, just as was found to be the case with the adult specimens of this same species. The young of Glossiphonia were secured in much greater abundance than those of Hemiclepsis, and thus permitted a more thorough study of their responses. The young of this species are hatched in egg saes as previously described. Upon the dis- integration of these saes the small leeches attach themselves by their posterior suckers to the ventral surface of the parent leech. In this position they are carried until they reach a considerable size. I have not been able to determine just what is the cause of their ‘‘weaning,’’ though it no doubt is to be explained as the resultant of two or three factors. One of these is the de- creased thigmotactic response of the young specimen as it be- comes older. Another factor is a purely mechanical one; the increase in size causes the young to become a serious impediment to the progress of the parent, and the larger size makes the burden easier to be rubbed off. Then, too, there is a limited space for the carriage of young as the result of their increase in size. This is obvious from the fact that the older the speci- mens of young carried, usually the smaller the number of young to be found attached. The formation of collections in the young, scarcely more than one or two millimeters in length, when removed from the body of the parent, is as clearly pronounced as we find it in the adult elossiphonids. The formation of one of these collections is a very interesting performance to observe. Some eight or ten dozens of young of varying sizes, taken from several parents, were placed one afternoon in a small circular glass dish. By the next morning they had grouped themselves into three collec- tions in the angles of the dish. These groups were broken up 1913] Gee: Behavior of Leeches 243 and the formation of a new set of collections observed. The young would, in some of the cases, attach themselves to the bodies of other young, a lively squirming resulting in the endeavor of the afflicted specimen to get rid of the imposed burden. The impediment afforded by the attached leech caused a slowing of movement of the specimen carrying the load, and finally a cessa- tion of movement of the two. With this as a starting point, a eroup of some thirty or forty specimens was formed. In other cases, a specimen moving about would come in contact with the dish where the bottom and sides meet, and the region being one of low light intensity, the young individual would come to rest, and from this as a starting-point a collection would be built up. The position of one of the larger of these groups was so shifted that the young leeches composing it became subjected to the influence of strong sunlight. The result was a slow disin- tegration of the collection, many of the animals composing it moving, after a series of random movements, into a less lighted portion of the dish. Some of the individuals remained in the eroup, however, for a couple of hours in the intense sunleght, failing even to move to a region of less heat and light, the thig- motactie proclivities clearly overcoming the tendency towards negative phototaxis. In the groups formed the young were observed to execute undulatory respiratory movements just as did the parent form. No new type of locomotor response, in so far as the free move- ments of the young are concerned, is to be noted in the young as contrasted with the old, though the habit of having themselves carried around is a trait peculiar to the young. Moltschanov (1911) has found in specimens of Glossiphonia and Hemiclepsis that the young when removed from the body of the parent continue to live for only a short time. This obser- vation he cites as evidence supporting the conjecture that the young of these two genera are nourished for a part of their ex- istence by a secretion from the cells of the ventral surface of the parent body. Bolsius (1911) rather refutes this idea and would explain the condition as resulting from insufficient oxygen supply, since the parent form aerates the young during its own undulatory movements. 244 University of California Publications in Zoology [Vou. 11 In the dish with some young of Glossiphonia stagnalis I placed a living earthworm, the young leeches being first aroused from the groups which they had formed. The same tendency to hang on as that which enables the young to secure its hold on the mother served in this case to cause it to attach itself to the worm. When the animals became attached to this they fed just as do the older leeches, the outline of the digestive tract standing out a vivid red from the blood contained in it. When they had become ‘‘full’’ they left the worm and formed collections around the edge of the dish. Within a few hours after the worm was placed in the dish, of the five or six dozens of young leeches, fully two-thirds of them showed upon examination that they had fed upon the worm. These young after having been fed only once in this manner were kept alive with only a few changes of water in the dish for over a month. The fact that this can be done, and that the young leeches perform undulatory movements for respiration themselves, would seem sufficient evidence to dismiss as improb- able the view held by Bolsius (1911) that the death of the young leeches removed from the body of the parent results from the lack of oxygen. Lack of food would seem a more important factor, since with this supplied they are able to live for over a month, or with sufficient trouble can, I believe, be reared to maturity. Whether the food of the young is partly derived from the secretions of the parent as suggested by Moltschanov is a matter which I have not been able to settle. A number of leeches carrying young were supplied with several earthworms as food, and after the parents had fed to satiety the young car- ried on them were examined. Several of them were found to contain blood in their digestive tract. Thus it is probable that the young gain a certain amount of their nutriment in this manner. Also they are undoubtedly able to be separated from their parents by attaching themselves to the food upon which the parent may be feeding, and upon securing a sufficiency they may find their way to a place of refuge and comfort upon some other foster-parent which may happen to pass their way. Bolsius (1911) states that he has observed young leeches to leave their parent and find their way back again to the same individual 1913] Gee: Behavior of Leeches 245 which they left. This is not at all impossible, but is, I believe, more likely to be the result of accident rather than any selective action for a certain parent on the part of its young. 4. OPERATION EXPERIMENTS The anterior ends of a couple of dozens of specimens of Dina microstoma were removed at various distances along the body length. These operated specimens were allowed four or five days for recovery from the shock effects of the decapitation before experiments were conducted on their behavior. Observations at this time showed little difference, except for vigor, in the character of responses as contrasted with that five months later. Loeb (1894) states that he has kept operated leeches for a year without regeneration: ‘“‘Schneidet man einen Blutegel in der Mitte entzwei, so zeigen die beiden Stiicke durchaus verschiedene Reaktionen. Die Wunde heilt sehr bald und die Stiicke konnen ein Jahr und liinger leben, ohne dass jedoch, wie bekannt, irgend welche Regeneration stattfindet.’’ Morgan (1901) says with re- gard to regeneration in leeches: ‘‘A leech is not much more complicated than a marine annelid, yet it has little or no power of regeneration.’’ Gluschkiewitsch (1907) states in a prelimi- nary report that he finds in the young of Clepsine (Glossiphonia) tessulata a regeneration of both the anterior and posterior ends. Adult specimens were not used in the experiments, and this fact may afford the basis of the difference between his results and those of other workers. He says: ‘‘Nach 23 Tagen waren unter den am Vorderende amputierten Individuen drei vollstindige und fiinf unvollstiindige Regenerate zu sehen.’’ MHirshler (1907) found from sections of operated adult specimens that regener- ation to a slight degree occurred in Nephelis, Clepsine (Glossi- phonia), and Hirudo. The process, however, amounted to little more than a wound closure. Although regeneration was not made the subject of any series of experiments, some observations were incidentally noted in this regard. Many of the specimens decapitated have continued 246 University of California Publications in Zoology (Vou. 11 alive and in good condition for six months. No perceptible signs of regeneration appear in any of the individuals, neither the anterior nor the posterior end regenerating new segments. No sections of the leeches have been made to determine to just what extent regenerative processes have taken place. Not all of the specimens operated upon have survived for as long as six months, the mortality being approximately seventy-five per cent. The wounds of the surviving specimens have in practically every case entirely healed over. What the result of such operations might be upon subsequent regeneration in young Dinas is a matter of uncertainty. The work of Gluschkiewitsech (1907) is certainly suggestive in this regard. When approximately the first eight anterior segments are removed from the body of Dina microstoma, the operation has the effect in most eases of setting the animal to swimming vigor- ously about in the dish. After a short period, the decapitated specimen settles to the bottom, becoming attached by the posterior sucker, the body stretched along the bottom of the dish. Except for a slight occasional movement of the anterior end, here it may remain for many hours. A slight stimulation of the posterior end of such an animal produces an unequal contraction of the dorsal and ventral longi- tudinal muscles of the body, causing the leech to become arched, and its anterior end to be pressed against the bottom of the dish. Since the anterior sucker is not present, progressive movement cannot be made effectively by looping; so the muscles are relaxed, and the body assumes its previous position. In some eases, the pressure of the anterior end against the substratum affords suffi- cient leverage for the animal to drag its posterior sucker forward a short distance. This would seem to indicate that the mechanism for forward movement by looping is present except for the an- terior sucker. The lack of this produces a clumsiness of response, but the reflexes constituting the movements of this type are all present in the decapitated specimens. The reaction of the decap- itated specimens to an average stimulus is usually the swimming reflex. This is performed in a perfectly co-ordinated manner, though the blunt anterior margin forms not nearly so efficient a steering agent as does the attached graceful anterior end. 1913] Gee: Behavior of Leeches 247 To contact stimuli of the anterior end there is a varying responsiveness and an equally varying type of response. Much of this variation is to be attributed to different recuperative capacities of the animals subsequent to decapitation. The ma- jority of the reactions given to contact stimulation of the anterior end are turns away from the stimulus. However, all of the varied combinations of responses, such as turns toward, reversal followed by swimming, ete., are secured in operated specimens, much as in the case of normal individuals. The manner of execu- tion of these reactions is rather clamsy when compared with the quick responsiveness of the normal active leech. In decapitated specimens, a very striking reflex is secured which is not prominently expressed in the intact leech. Stimu- lation of the mid-dorsal region a few millimeters posterior to the wounded surface produces a vertical elevation of the anterior end. The glass rod may be moved back and forth along this region many times without evoking the swimming response of the animal. Were one to allow one’s anthropomorphic tendencies sway, one might very readily imagine that the leech gains evident enjoyment from having its back scratched. The decapitated leech is not altogether incapable of sponta- neous movements, but certainly the removal of the anterior end has a very marked effect on the degree of the animal’s activity. A specimen may remain for several days in a single attached position, performing no more than a few undulatory movements during this period. Much of this lack of internally initiated responsiveness is to be attributed to the lowered vitality of the decapitated animal. Some of it, I believe, is to be assigned to the loss of the anterior ganglionic centers. Specimens six months after operation show more decidedly this lack of movement. Perhaps the most significant change in the behavior as the result of decapitation is the reduction of the tendency towards random movements. While not restricted to the anterior region of the body, the ability to perform these feeling movements seems to find its chief expression in the first few anterior segments. As has been stated in a previous portion of this paper, the fune- tion of these random movements is largely that of orienting the body before the attachment of the anterior sucker. With the 248 University of California Publications in Zoology [Vou.11 anterior sucker and the segments of the body closely contiguous to it removed, there is a reason for the lack of responsiveness in this regard. The anterior end relieved of the posterior portion of the body will feed if given the opportunity, performs random movements rather in excess of the normal individual, and if consisting of half or more of the body length swims readily through the water. The looping response is performed, rather clumsily, since the animal is without the posterior sucker. Frequently groups consisting of several decapitated Dinas are to be found in various places in the aquarium. To this extent the thigmotaxis of the leech is expressed. I have kept stones in the dish with such specimens for several weeks, but for some reason the leeches do not accumulate underneath these hiding places. Not so with the anterior ends, however, for these soon find the stones, and remain persistently underneath them until disturbed. Undulatory movements of respiration are made by the various portions of the body, but not to any considerable degree. The posterior regions of the body, minus the anterior, are rather the more proficient in the performance of these movements than any other parts, though I have seen a small portion of the body with- out either anterior or posterior sucker undulating itself rather rapidly so as to secure more efficient aeration. 5. FUNCTION OF THE BRAIN The funetion of the brain is, to a certain extent at least, the production of spontaneity of movement. This is indicated by the fact that there is a greater excess of movements of this char- acter in the anterior ends removed from the body than in the decapitated specimens. This is markedly true even in leeches some months after operation. To a certain degree, the brain is a co-ordinating center, serving to make the locomotor responses more efficient as the result of the proper interaction of the parts producing the progressive movements. Bohn (1907) has claimed for Branchellion the power of simple “‘phenomenes associatifs.’’ Yerkes (1912) has found what 1913] Gee: Behavior of Leeches 249 he considers as evidence of association formation in the earth- worm. This would lead one to conjecture that the same capacity is present in the leeches experimented upon in connection with the present work. No experiments have been conducted to deter- mine whether the leeches Glossiphonia stagnalis and Dina micro- stoma are capable of forming simple types of associations. It is not at all improbable that such is the ease, but I see no difficulty in accounting for any of the features of their behavior on the basis of the simpler characteristics common to the behavior of the lower organisms. 250 University of California Publications in Zoology (Vou. 11 B. MODIFIABILITY IN THE BEHAVIOR OF THE LEECH DINA MICROSTOMA MOORE I, INTRODUCTION As a rule, the factors which determine the behavior of an animal at a given moment are many and complex. It has been shown conclusively by numerous workers that these factors are internal as well as external. Consequently, behavior is the re- sultant of the action of these two classes of stimuli: sometimes the internal stimuli preponderate ; again, it is the external stimuli which exercise the greatest determining influence. The complex interrelations of these two classes of stimuli make the problem of analysis of behavior a difficult, though not impossible, one. The various factors can be intensified or diminished and the effects of these changed relations observed. Observations secured under these controlled conditions will provide data which are of such a nature as to contribute much to the solution of the problem of modifiability. With such a number of factors involved, it is evident that a wide range of variation in both degree and type of response will be the result. However, there is a limit to this modifiability, which usually is in direct proportion to the needs placed upon the organism by the varying conditions of its environment. To discover the physiological bases for these reactions, and the limits consti- ce 9 of power of adjustment of these ‘‘physiological bases, tutes the problem of modifiability. As to the importance of this phase of animal behavior, Jen- nings (1905) says: ‘‘A thorough study of the modifiability of reactions to external stimuli in lower organisms seems at present one of the great desiderata in the study of animal behavior. Re- cent work has been devoted largely to the study of sharply defined forms of reaction and to the discovery of conditions under which these forms appear in a typical way. As a result, there is a widespread impression that the behavior of lower organisms is 1913] Gee: Behavior of Leeches 251 composed of invariable reflexes, occurring always in the same way under the same external circumstances. This is far from the truth and leads, as it seems to the writer, to a fundamentally false conception of the nature of animal behavior. Inner states and changes are fully as important in determining behavior as are external stimuli, modifying fundamentally the reactions which the latter produce.’’ The works of Jennings (1902, 1905, 1906), Bohn (1907, 1909), Yerkes (1906), Holmes (1905, 1907, 1911), Hargitt (1906), and Allee (1912) are the chief contributions to this phase of animal behavior. Considering its importance, the field is a rather neg- lected one, and certainly its complexity will afford work enough for some time to come. The following study was undertaken to learn, so far as possible, the general features of modifiability in the leech, Dina microstoma Moore. Except where specifically mentioned, no other species of leech was employed in the experi- ments discussed in the section of this paper dealing with the subject of modifiability. II. DIFFERENT RESPONSES TO THE SAME STIMULUS Every animal with any degree of complexity of structure shows a considerable variation, qualitative as well as quantitaive, to successive applications of the same stimulus. Not only is this true in the behavior of the more complex organisms, but it holds with equal force in certain of the lower forms. A case in point, which has become classic in the literature on animal behavior, is the modified responsiveness of Stentor (Jennings, 1906) to particles of carmine repeatedly applied to its disk. The work of Pearl (1903) has served to emphasize this feature of behavior in the planarian. Jennings (1906) has furnished a very sug- gestive analysis of the factors determining the direction and character of the movements in the earthworm. The leech, how- ever, is an aquatie annelid, and its repertoire of responses differs considerably from that of the earthworm. For this reason a classification and analysis of its different reactions to the same stimulus seem desirable. 252 University of California Publications in Zoology (Vou. 11 1. ReEacTIONS TO STIMULATION OF THE ANTERIOR END The extreme sensitiveness of the body of the leech has been considered in the first part of this paper. The animal is very responsive even to slight stimulation of any part of its body with a flexible hair bristle or a delicate capillary glass rod. In the majority of cases the response is a turn or movement away from the stimulus; yet there is a decided variation in this regard. Several different responses varying in character and degree can be secured upon stimulation of a localized region of the anterior fifteenth of the body. Some responses to stimulation of one side = Y S| Fig. 5.—Five different responses to tue same localized contact-stimu- lation of the anterior end of Dina microstoma: (a) turn to the left, (6) turn to right towards the stimulus, (c) turn to left followed by turn to right, (d) turn to right followed by turn to left, and (e) a complete re- versal of direction by turn to left. Yj 1913] Gee: Behavior of Leeches 253 are listed below. These responses were secured by stimulating as nearly as possible the same region of the right side of the anterior end of the body, though this is confessedly difficult to do in as active a form as Dina microstoma. The stimulus was that from a flexible bristle fixed rigidly into a split wooden handle, the bristle being bent about the same degree at each application of the stimulus. In this way there was secured, as nearly as is practicable, fairly exact localization and an even intensity of stimulation. The responses to stimulation in this way are as follows: 1. A turn to the left and movement forward in that direction. 2. A turn to the left, then to the right and forward movement. 3. A turn to the right in the direction of the stimulus and forward movement. 4. A turn to the right, followed by a turn to the left and forward movement. 5. A release of hold on the substratum and forward movement by the swimming reaction. 6. Disregard of the stimulus except for local contraction, and continued forward movement. 7. Local contraction of the part stimulated, the animal hug- ging the bottom of the dish. 8. A lifting of the anterior end and execution of random feeling movements. 9. With posterior end attached, a complete reversal of direc- tion by a sharp turn to the left, followed by swimming reaction. Many other combinations of these reactions might be men- tioned; for example, reactions number one, two, and three might be performed as turns merely, not being accompanied by for- ward movement. It will be observed, however, that though there is a wide variation in degree and combination, the whole series can be classified as follows: (1) turns to right or left or up and down; (2) forward moyements by looping or swimming; and (3) local contraction of the part affected. While it is a difficult matter to explain the order of response in each ease, the knowledge of the mechanism of these reactions, as discussed in the first part of this paper, serves to suggest many valuable points toward this end. 254 University of California Publications in Zoology (Vou. 11 2. ORDER OF RESPONSE IN TWENTY-FIVE STIMULATIONS OF THE ANTERIOR END It can be seen very readily that not all of these reactions are adaptive in character, especially in the ease of those which would tend to lead the animal in the direction of the stimulus. It was noticed in the various stimulation series performed in this work that the first responses of the animals which had not been stimulated for some time previously were usually such as to carry it out of the region of the stimulus. This condition was, however, far from invariable. With the idea of determining the relative frequency of the non-adaptive responses, the reactions of six individuals to twenty-five successive stimulations of the character above indicated were recorded, and the more common types of response tabulated. The entire record of Individual one is given, since to do this is to afford a clearer idea than would any attempt at a description of the general character and order of response. The stimulus in each case was applied with a delicate glass rod and to the right side of the anterior end of the body of the leech. RESPONSES OF INDIVIDUAL I TO TWENTY-FIVE SUCCESSIVE CONTACT STIMULATIONS . Complete recoil by sharp turn to left, movement forward. . Turn to the left and back slightly to the right, movement forward. . Turn to left and then to right. . Turn to right. Turn to right. Local contraction of part stimulated, movement forward. Turn to left and back to right. Turn to left and back to right. Turn to left. 10. Turn to right. 11. Turn to left. 12. Turn to left and then to right. 18. Local contraction and movement forward. 14. Turn to left. 15. Turn to left and then to right. 16. Turn to right. 17. Turn to right and then to left. 18. Turn to left. Nan PfP wpe © 9 1913] Gee: Behavior of Leeches 19. Turn to left. 20. Local contraction followed by swimming movements. 21. Loeal contraction, moved forward. 22. .urn to left. 23. Turn to left and back again to right. 24. Turn to left. 25. Turn to right. The accompanying table (see table IIIT) does not attempt to show the number and succession of the entire nine responses catalogued as the result of a number of contact stimuli, but only TABLE III NUMBER AND SEQUENCE OF RIGHT AND LEFT TURNS IN TWENTY-FIVE STIMULATIONS OF THE RIGHT SIDE OF THE ANTERIOR END Number of times turned to right in succession at different times -....... Number of times turned to left in succession at different times -...... 3 Number of times turned to left fol- lowed by turn to left ....................-- 4 Number of times turned to right fol- lowed by turn to left ...................-.. 3) Number of times of complete recoil GOL ett Sees cerca srensecnanecneeravcstecstereanence Number of individual AN bo bow bo me ee bo bo 1 II bo & po bo bo 1 1 DUT ow poe ra Vi* bo bo bo bo po bh Ww & w& BeHeHH pH ra V bp“ bo aa 1 1 4 bo Lipa ar He a) H * The apparent discrepancy in that the number of responses sometimes totals more than the actual number of stimulations is due to the fact that a turn to the right may fol- low, say two previous turns to the right and itself be followed by a turn to the left. Thus the response would be classified twice. Several such combinations are possible, and it is for this reason that the total number of responses is more than twenty-five in the cases indicated by the asterisk. 256 University of California Publications in Zoology (Vou. 11 the more common and important of these are given. The great predominance of the adaptive reaction, a turn to the left away from the stimulus, is very plainly indicated. A decided ten- dency for a reaction to be repeated several times in succession is also to be observed. The significance of these facts in the explanation of the nature of the reactions is considered in a succeeding paragraph. 3. REACTIONS TO STIMULATION OF THE PostTERIOR END To contact stimulation of the posterior end the responses are much more stereotyped, due partly perhaps to the fact that the posterior sucker is attached when the stimulus is applied. So far as I have been able to determine, there are only two types of reactions when the stimulus is applied to the posterior region of the body. These are as follows: 1. By the looping response, much as a measuring worm moves forward. 2. By the release of attachment to the substratum, and the execution of eel-like swimming movements. The first response is that usually given upon the application of a slight stimulus to the animal when it is in a resting condition, or in a state of low sensitivity produced from some such cause as fatigue. The swimming response is the more commonly evoked, and is the expression of an active condition of the organism. The rapidity of its execution serves to remove the animal speedily from the region of stimulation. 4. DETERMINING FACTORS OF THE DIFFERENT RESPONSE TO THE SAME STIMULUS (a) Intensity of stimulus.—It is obviously impossible to stim- ulate the leech each successive time to the same degree. This fact alone plays its part in determining the character of the response to contact stimulation of a certain degree, though its influence has been eliminated so far as practicable. Under uni- form conditions, when the body of the animal is extended, stim- ulation with a fine hair bristle or a capillary glass rod on the right side of the anterior end of the body will usually produce 1913] Gee: Behavior of Leeches bo 1 a a turn of the body to the left and away from the stimulus. A much stronger stimulation with the animal in the same position will produce a still farther turn to the left; while a stimulus of still greater intensity may cause the animal completely to reverse its direction of movement, and combine with the turn the swim- ming response. = : e t a S E f > + ido] 15° + pie + 4 L o 5 a neo oe :: : EEE at Weetuece! Gentes ot i “EM 4 [ 4 BERLE EEE A BEY Ngumiel s : aeseeeeeeeatdtaaseeeltt eaMtaa : ac} 5 paanen at t PRES z | | he H seseb becca aces reveshsee\ ed al St Pp jaan 1 r i Shere. ai 4 | Fig. 8.—Influence of strychnine on curve of activity in the leech. Scale same as in preceding figure. Plotted from record of individual 4, Table 8. 276 Unwwersity of California Publications in Zoology (Vou. 11 TABLE VIII INFLUENCE OF STRYCHNINE UPON THE DURATION OF THE SWIMMING RESPONSES EVOKED BY REPEATED CONTACT STIMULATION Duration in seconds of swimming response in ten specimens Order of Dina microstoma of stimu- lation 1 2 3 4 5 6 7 8 9 10 Average 1 6 ile 15 iy 10 25 7 17 10 10 13.4 2 13 «413 3) ol 22) 920) 10 Bj} AAO) al 15.7 3 Uf i aly 7 6 30 @ aR, ep Pal 13.4 4 15 5 i} Pay IEE aly ey at) 8 14 13.9 5 C2 sl Oe: ORL iany eile 3 5 13.3 6 16 4 3 «18 5 10 9 4 6 10 9.5 vi 15 sje) ee aly alah 7 uf 7 ele 10.4 8 5 10 8 6 8 22 4 6 5 14 8.8 9 16" (25) 992) 13) 2 7 3 15 14 8 12.5 10 Sie OF eel ieee 3.0) 3 8 if S439 13.9 11 8 10 8 12 6 Oe OL OLS ies 11.6 12 7 8 4 9 8 8 29 10 8 21 11.2 13 8 10 4 8 3 4 47 23 3 12 12.2 14 ue) lal 8 5 2 8 20 5 6 12 8.4 15 7 15 4 30 6 7 23 8 19> 43 13.2 16 3 5 Sieelis 4 6 14 5 5 uf 6.9 17 4 10 4 10 0 5 3 8 9 3 5.6 18 38 380 24 5 0 82! 5 2 g'9 19 0 10 Gali 5 10 3 6 5.3 20 8 8 16 1 23 ul 3 6.6 21 18 8 20 0 8 22 0 7.6 22 ee Al 8 dO! 22 ean 2S 6 13 6 23 see, TU 5 8 a) See ee eee 130 8 7.6 24 i alt uf 4 10 4.4 25 13 #15 «#138 9 6 5.6 26 7 8 28 6 9 5.4 27 8 13 47 0 4 7.2 28 Ge PD 0 4.3 29 6 3 616 2.5 30 4 40 10 acs 5.4 21 pen 1 al} 8.) (20%) 229) ee 0 8 22 0 7.6 32 = ESAS 15 8 oper “re atc “55 aoe — 2.3 33 20 14 3.4 34 is) LG 6.1 35 16 8 2.4 36 ais 3 2 37 20 2 2.2 38 12 7 aly) 39 0 5 0.5 40 3 0.3 41 0 0 1913] Gee: Behavior of Leeches 277 Hf EHF TA . ie ' t i 200 1 T etal aes Coe ! Hee rH 1 rH it jeanal T =a Ty tt ne t f tt t t ee pate] i i T eeceeavaee aeevelsezaee Es ode, asa iei ev eed enue! ft i i i t t im ao rat 1 100 cat 7 Apel HH | i B D r if A =r a a ‘ ct H TT ul n THe ae 1 i T im an { ae 7 1 | a rho iB T rere f Fett eet is Hot t et i we PEER EEEEEEEN sogeean\ Seo 10 ! 1 sasaere cacues FH 1 foo nage Tot ES (BSE al 1 imme | Fig. 9.—Influence of nicotine on curve of activity in the leech. Solid line repre- sents response of individual 7, table IX; dotted line, the average of ten specimens. Seale: five spaces on abscissa represent a single stimulation period; one space on ordinate, two seconds’ duration of swimming response. bo -] 8 Unversity of California Publications in Zoology (Vou. 11 is immediately removed to a dish of clean water two to four hours serve to remove the nicotine sufficiently for the animals to execute slow but co-ordinated movements. There is consid- erable variation in this regard, however, since many of the leeches fail to recover entirely from the effects of the nicotine. TABLE IX INFLUENCE OF NICOTINE UPON THE DURATION OF THE SWIMMING RESPONSES EvoKED BY REPEATED CONTACT STIMULATION Duration in seconds of swimming response in ten specimens Order of Dina microstoma of stimu- — — lation 1 2 3 4 5 6 7 8 9 10 Average 1 9 5 45 20 10 7 15 38 6 5 16 2 5 15 16 12 14 9 19 4 15 3 11.2 3 3 8 6 8 15 21 12 12 22 10 12 4 13 22 13 57 2 Wy 16 9 12 iit 19.2 5 25 12 9 220 246 16 30 22 130 3 (Als 6 19 80 5 13 12 90 34 6 52 22 32.3 Tf 12 11 54 0 8 10 13 5 20 7 14 8 3 265 9 0 140 220 8 8 4 65.7 9 182 20 292 15 56 330 9 210 111.4 10 28 175 10 6 10 31 8 15 28.3 11 8 65 0 0 40 20 23 0 15.6 12 4 17 See aeee eS sec 14 0 10 oes 4.5 13 5 WAS paths yh Aes shen ee Senne Arras an 8c) 3.2 14 0 12 eee aes 60 eens 10 =o 14 = 3.6 15 S28 Si ky ky beak ies ees Ge” aes 1.8 16 eae? 10 sete “ns ae Bee 0 =e 0 Hen i 20 0 0 4. CocAINnE With regard to the action of cocaine in invertebrates, Cushny (1910) says: ‘“‘In some eases, notably in the higher inverte- brates, the final depression is preceded by a stage of increased movement, and it is said that irritability of the nerve is also augmented at first.’’ This certainly seems to be the case in Dina; for here the activity is at first extremely accentuated, and depression as abrupt. The final effect of the drug seemed to be that of paralysis, the longitudinal muscles often contracting until the body of the animal was very strongly curled. From this 1913] Gee: Behavior of Leeches 279 position no degree of stimulation was sufficient to cause straight- ening out of the body or progressive movement. The strength of cocaine used in these experiments was 0.08 per cent solution. The table showing duration of response (see table X) and the graph (see fig. 10) indicating the same show very clearly the character of the response. Depression was speedy and practi- eally absolute. All of the animals recovered upon being kept in clean water for several hours. 100 + Bene mn 50| - tt tt Fig. 10.—Influence of cocaine on curve of activity in the leech. Plotted from average responses of ten leeches. Seale same as in preceding figure. 5, CHLORETONE Chloretone was tried and found to be very similar to cocaine in its effects. The initial period of excited responsiveness was even more marked than in the case of cocaine. The following table (see table XI) very clearly indicates this fact. Complete and rapid depression occurred as the result of the poison and the excessive activity of the animal. With a 0.05 per cent solution of chloretone full relaxation of the muscles was secured 280 University of California Publications in Zoology [Vou. 11 in most cases within fifteen or twenty minutes. Upon removal to clean water the leeches within two or three hours recovered sufficiently to perform slow but co-ordinated movements. 6. MaGnestum SuLPHATE Aceording to Cushny (1910), the magnesium salts have a very powerful action when injected into the higher animals either hypodermically or intravenously. The most characteristic effect is complete anesthesia resembling that induced by the chloro- form group and ending in fatal cases in paralysis of the respira- tory center. A strength of magnesium sulphate as high as N 34 required a rather long period to produce complete depression. In from one to one and a half hours this had occurred. As can be seen from the accompanying table (see table XII), there is at first an increasing excitement, this being followed by a correspond- ingly slow depression. To a certain extent, at least, paralysis seems to take place in the muscles, a knotted twisting of the body occurring. Later this was followed by relaxation, no re- sponse other than a slight lateral movement of the anterior end occurring even to very strong stimulation. This treatment seems to have been more fatal than any of the other substances tried ; since out of four individuals tested only one revived to any extent in twenty-four hours, and this not to a stage where co- ordinated movements could take place. TABLE X INFLUENCE OF COCAINE UPON THE DURATION OF THE SWIMMING RESPONSES EvoKED BY REPEATED CONTACT STIMULATION Duration in seconds of swimming response in ten specimens Order of Dina microstoma of stimu- lation 1 2 3 4 5 6 7 8 9 10 Average 1 18 25 188 215 190 150 185 200 6 10 113.7 2 265 12 4 6 15 5 4 50 230 9 60 3 7 125 2 4 5 3 6 7 +10 222 38.6 4 0 5 6 3 2 iL 2 6 5 15 4.5 5 2 7 1 0 0 1 il 2 2 1.6 6 3 2 2 0 0 0 0 0.7 i at if 0 0.8 8 0 2 0.2 9 0 0 281 Behavior of Leeches . Gee 1913] ool Fig. 11.—Influence of magnesium sulphate on curve of activity in the leech. Plotted from record table XII. Scale same as in preceding figure. ost individual 1, 282 University of California Publications in Zoology [Vou. 11 TABLE XI INFLUENCE OF CHLORETONE UPON THE DURATION OF SWIMMING RESPONSES EvoKED BY REPEATED CONTACT STIMULATION Duration in seconds of swimming Order response in five leeches of stimu- AW —— lation 1 2 3 4 5 Average 1 180 265 360 334 385 304.8 2 30 28 20 20 30 25.6 3 18 5 18 8 90 28.0 4 10 0 10 25 16 12.2 5 3 4 18 12 7.4 6 0 0 7 5 2.2 7 eee 0 0 0 7. CARBON DIOXIDE It is known that oxidation and destruction of carbohydrate in the body result in the formation of at least two waste sub- stances, both of an acid character, namely, carbon dioxide and lactic acid. These two products of metabolism are considered important factors in causing fatigue in skeletal muscle. For them Lee (1910) has suggested the term ‘‘fatigue substances.’’ This investigator (1907) found in the frog that upon injecting a 0.07 per cent sodium chloride solution containing considerable quantities of carbon dioxide into the muscles of the leg ‘‘it will be observed that the curves of the muscle under the influence of carbon dioxide, from the Ist to the 151st contraction inclusive, are higher than those of the normal musecle-—in other words, carbon dioxide exerts at first an augmenting action. From the two hundred and first contraction on the fatiguing effect is manifest.’’ A leech placed in 100 em. of tap water + 100 em. of carbonated water was at first excited to marked activity. Within five min- utes the animal showed depression to the extent that it was incapable of progressive movement. The specimen was imme- diately removed to a dish of fresh water. It at once began movements of the anterior end, and five minutes later performed swimming movements of a partially co-ordinated character. This was at ten o’clock, and seven minutes after the animal swam actively about in the dish upon being stimulated, though dis- playing a condition of lower tonus. At twenty minutes past ten the leech appeared entirely normal in its responsiveness. 1913] Gee: Behavior of Leeches bo [oe] ive) TABLE XII * INFLUENCE OF MAGNESIUM SULPHATE Upon THE DURATION IN SECONDS OF SWIMMING RESPONSES EvoKED BY REPEATED ConTACT STIMULATION Order No. of leech Order No. of leech of stimu- — Average of stimu- a—_—_7 Average lation 1 2 duration lation 1 2 duration 1 10 5 7.5 27 15 20 17.5 2 8 8 8 28 0 14 7 3 12 8 10 29 so 40 20 4 6 14 10 30 “6 110 55 5 8 7 7.5 31 Se ey iliss 107.5 6 7 42 24.5 32 ise 25 12.5 7 4 15 9.5 33 Sete 22 11 8 13 ¥) 11 34 = 7 3.5 9 55 6 80.5 35 6 3 10 36 6 21 36 5 2.5 a) 35 5 20 37 12 6 12 14 a 10.5 38 10 5 13 30 20 25 39 5 2.5 14 18 32 25 40 8 4 15 28 12 20 41 3 1.5 16 31 if 19 42 5 2.5 17 70 8 39 43 4 2 18 10 20 15 44 2 1 19 35 8 21.5 45 3 1.5 2 6 11 8.5 46 i 3.5 21 57 16 85.5 47 3 1.5 22 66 8 37 48 2 1 23 54 25 39.5 49 3 1.5 24 179 340 259.5 50 2 1 25 21 130 75.5 51 0 0 26 45 62 53.5 Much the same result was secured upon placing leeches in water through which a vigorous stream of carbon dioxide gas had been passed for about twenty minutes. Thus in leeches carbon dioxide is at first accelerating in its action. Depression of the leech comes quickly, but recovery takes place in a rela- tively short time. 8. Mono-Porasstum PHOSPHATE This substance has been found to be one of the group pro- ducing fatigue in skeletal muscle. The experiments of Lee (1907) on the leg musele of the cat show that at the beginning of the test the contractions of the phosphate muscle were much 284 University of California Publications in Zoology (Vou. 11 greater than those of the normal muscle. After one hundred and seven contractions the phosphate muscle began to show signs of depression. Leeches placed in a one-seventh gram molecular solution of mono-potassium phosphate (KH,PO,) showed signs of consid- erable excitation extending over some length of time. Within three hours the most of the leeches were in a condition near complete depression. The muscles of the animal appeared flaccid, showing no signs of paralysis. Recovery took place rather slowly as compared with that following the use of carbon dioxide. Within three to four hours after removal to clear water the leeches were usually able to perform well co-ordinated movements, though at a rather slow rate. By the next morning the leeches had practically entirely recovered normal responsiveness. 9. Lactic AcIp Leeches placed in a 0.08 per cent solution of lactic acid (sp. gr. 1.21) required eight or more hours for depression to occur as the result of the solution. With a 0.2 per cent solution this result was secured in a much shorter period. Augmentation of activity upon stimulation seemed to be marked almost to the time of depression. In fact the action of lactic acid on leeches was rather different from that of carbon dioxide and mono- potassium phosphate. A much longer time was required for depression to occur; and when the animal reached this stage the substance had so injured the animal as to prevent its recovery. Whether this is due to the difference between lactic acid and paralactie acid was not made the subject of investigation. Rich- ter (1899), however, states that in all its transpositions para- lactic acid behaves like ordinary lactic acid, and hence the same chemical structure is accepted for it. The existence of the two modifications is explained by him as due to the asymmetry of a carbon atom in the acid. 10. Discussion or FATIGUE Fatigue represents a distinct physiological state in an animal. This state carries with it a more or less characteristic type of response in the leech, and very materially influences its degree 1913] Gee: Behavior of Leeches 285 of responsiveness. From the experiments discussed in the several preceding pages, it becomes clear that the modus operandi of this fatigue is not essentially different from that known in the higher animals. The various depressants used act upon the leech in a manner fundamentally very similar to their action upon vertebrate types. Carbon dioxide, mono-potassium phosphate, and lactic acid have been found in the fatigued muscle of the higher forms, and when applied to these artificially produce a condition of depression. While the analysis of fatigued leech muscle has not been made, I have found that these same sub- stances produce a condition of fatigue in this form. It appears very likely to the writer that in the action of these “fatigue substances’? is to be found the explanation of many of the ‘‘states of excitement’’ discussed in a preceding portion of this paper. Such results as those secured from the various substances used on leeches lead one to extend to the lower organisms the fol- lowing conclusions of Lee (1907): ‘‘The facts here reported seem to emphasize anew and strikingly the great desirableness of a very careful and full investigation of the physiological actions on cells, tissues, and organs of the products of meta- bolism, both intermediate and final products. We seem not yet to realize how potent may be the influence of such substances. We incur the charge of being unscientific if without experimental data we deny to even the humblest katabolic product a possible role as a physiological reagent. It seems to me that physiology is destined to make great progress along the lines here indi- eated.’? Such a viewpoint as this is certainly suggestive in its bearing upon the future work in the field of animal behavior. VI. EFFECT OF COMBINED STIMULI 1. INFLUENCE oF Foop JUICES ON REACTION TO CoNnTACT (a) Normal Individuals —Often when a delicate glass rod is brought gently alongside the extreme anterior end of the leech the animal responds by inclining its anterior end in the direction of the stimulus and momentarily attaching the anterior sucker. An immediate recoil is produced, yet nevertheless a positive reaction is involved, the adaptiveness of which has been 286 University of California Publications in Zoology [Vou. 11 considered previously in its relation to the feeding responses of the animal. In studying the feeding reactions of the leech, it was observed that these positive responses seemed to be accentu- ated under the stimulating influence of the juices of a snail, its favorite food. This point was made the subject of a series of experiments on leeches in normal, starved, and well-fed condi- tions. Specimens which had been in the laboratory for a few days only were considered normal. One at the time, a half dozen of these normal leeches were tested for the number of positive re- sponses to thirty very light contact stimuli of the anterior end in the manner above described. After the responses of a par- ticular leech were thus secured in tap water, a considerable quan- tity of juices extracted by macerating a Limnea was added to the water in the dish. The number of positive responses to light contact stimuli was determined under these conditions. The results are indicated in the accompanying table (see table XIII). By positive (+) response is meant the actual application of the anterior sucker against the glass rod as a direct result of the stimulus; negative (—) indicates a direct turn away from the stimulus; and indifferent (-+) is a response such as local con- traction or a continued forward movement. The uniformity of the results in the different individuals is rather striking. The accentuation of the positive response under the influence of diffusing snail juices is not great, but the increased amount of indifference seems significant. This condition, while apparently TABLE XIII INFLUENCE OF SNAIL JUICE UPON REACTIONS OF NORMAL INDIVIDUALS TO Contact STIMULI.—THIRTY APPLICATIONS OF STIMULUS In strong diffusion Number In fresh tap water of snail juice individual + — tes + — + 1 13 14 3 13 8 9 2 9 14 7 12 6 12 3 12 13 5 12 6 12 4 5 17 8 8 7 15 5 8 16 6 12 6 12 6 13 14 3 14 6 10 Average 10 14.6 5.4 12 6.5 11.5 1913] Gee: Behavior of Leeches 287 non-adaptive, is indirectly of very decided advantage. The in- creased activity upon which the intensified indifference is de- pendent serves to bring the animal in contact with a wider field. Its anterior end must necessarily come in touch with the surface upon which it frequently comes to rest from swimming. Thus with the increased number of attachments there would be an increased likelihood of its successfully locating such food as might be in its immediate environment. (b) Starved leeches—Five leeches which had been starved for forty-five days were subjected to a similar treatment to that just described for the normal leeches. The accompanying table (see table XIV) indicates the results secured. The predominance of the negative response of the starved leeches in clean water is to be attributed to the increased irritability of the starved indi- viduals over that in the normal specimens. There is a striking increase of the positive responses, and a considerable difference in the number of indifferent responses under the influence of the snail juice, both of which conditions serve to reduce the number of negative responses in a striking degree. A comparison of the results secured from the starved indi- viduals with those from the normal individuals affords a good illustration of how the same external factor may affect two organisms in different physiological states. It also serves to show that the juices of the snail reinforce the tendencies toward positive reaction to contact much more in the starved individual than in the normal. It is scarcely necessary to emphasize the adaptive nature of this difference in behavior. TABLE XIV INFLUENCE OF SNAIL JUICE Upon REACTIONS TO ConTACT STIMULI IN LEECHES STARVED For 45 DAays.—THIRTY APPLICATIONS OF STIMULUS In strong diffusion Number In fresh tap water of snail juice 0 (— a =\ fr —‘— >) individual + == + + == + 1 11 19 0 19 4 7 2 10 18 2 ial 5 14 3 7 19 4 22 3 5 4 9 21 0 19 6 5 5 8 20 2 2 + 5 Average 9 19.4 1.6 18.4 44 7.2 288 University of California Publications in Zoology (Vou. 11 TABLE XV INFLUENCE OF SNAIL JUICE UPON REACTIONS OF WELL-F'ep LEECHES TO ConTAcT STIMULATION.—THIRTY APPLICATIONS OF STIMULUS In strong diffusion Number In fresh tap water of snail juice individual + — + + — + 1 8 18 4 8 7 15 2 10 12 8 9 11 10 3 9 12 9 5 9 16 4 7 19 4 12 6 12 5 5 15 10 10 10 10 6 9 13 8 19 6 5 Average 8 15 a 11 8 11 (c) Well-fed leeches—The responses of the well-fed leeches under the same conditions as those of the preceding experiments are not essentially different from what was found to hold in the normal individuals. Under the influence of contact stimulus without the reinforcement of snail juice there is a somewhat smaller number of positive responses than in the normal indi- vidual. The same condition is true under the influence of the snail juice. There is, however, a lowered responsiveness in the well-fed individuals which would tend to lower the irritability of the leech. This reduced irritability would tend to render the responsiveness to light contact stimulation more nearly like that of the normal individual which has not previously been excited to a stage of activity. 2. Light AND Contact A dish sixteen by sixteen by thirty-one centimeters containing three dozens of leeches was placed over a 25-watt Mazda light in a dark room, the dish being elevated on a tripod about eight inches in height. With the light turned off a stone was placed in the center of the dish, and underneath this within an hour had accumulated ten of the leeches. The light was then turned on, and the reactions of the leeches were carefully observed. At first the stimulus produced in the leeches under the stone a state of restlessness, indicated by side to side movements. In a few 1913] Gee: Behavior of Leeches 289 minutes, however, they became quiet, entirely disregarding the light. The leeches crawling freely about the dish were, however, excited to greater activity, swimming rapidly about in the dish and crawling up its sides. The light seemed to overcome their normal geotactie reactions. Three and a half hours after the beginning of the experiment the animals in -contact with the dish and stone were all in the same positions as at first. A half dozen of the others were at rest on the sides of the dish, some of them half out of the water. As many more were swimming about in the dish or crawling on the bottom, while the remainder were massed in clumps on the Ceratophyllum in the aquarium, well up towards the top and in the most shaded portion of the dish. Thus, light of the intensity used seems to overcome what geotaxis the leech may have, the orienting effect of its rays tending to carry the animal against the force of gravity. In the case of the leeches underneath the stone, their thigmotactic inclinations being satisfied, light of the intensity used had prac- tically no effect. Sherrington (1911) says: ‘‘It is not usual for the organism to be exposed to the action of only one stimulus at a time. It is more usual for the organism to be acted on by many stimuli concurrently, and to be driven reflexly by some group of stimuli which is at any particular moment prepotent in action on it. Such a group often consists of some one pre-eminent stimulus with others of a harmonious relation reinforeing it.’’ The cases of combined stimuli discussed in the preceding paragraphs afford good examples of how well this principle applies in the leech. In the ease of the food juice and contact stimulation, we have a prepotent stimulus in the food, and this reinforces the positive reaction, which represents distinctly one of the feeding reflexes. With light and contact combined, we have a prepotent stimulus in the contact of the animal with the under surface of the stone in the dish. These cases cited in the leech merely indicate the significance of combined stimuli on the behavior of the animal, and point to the fact that behavior represents a resultant action to varied groups of concurrent stimuli. 290 University of California Publications in Zoology (Vou. 11 VII. INFLUENCE OF INTERNAL STATES 1. Benavior oF WeEtLL-FED LEECHES Leeches fed to satiety the evening before and left in the dish overnight with an abundant supply of crushed snail for food were tested for the duration of swimming response as evoked by fifteen successive contact stimulations. The comparative curves (see fig. 12) derived from the data given in the following table (see table XVI) show the sluggishness of the well fed individuals as opposed to the responsiveness of the normal speci- mens. In this condition of satiety the same general dullness of response to stimuli of all kinds is evidenced, as is characteristic of the duration of swimming. The results given in table XVI represent the duration in seconds of the swimming response evoked by posterior end stimulation of comparatively uniform intensity. The average height of the curve of the normal indi- viduals is to be observed as considerably above that of the well fed individuals. The condition of the organism when fed to satiety suggests from the nature of its effect on the responsive- ness of the animal a close resemblance to what is secured upon partially fatiguing the individual. 15 HH Fig. 12—Curve showing comparative responsiveness of normal and well-fed individuals to contact stimulation. Dotted line represents re- sponses of normal leeches; solid line, the well fed. 1913] Gee: Behavior of Leeches 291 2. ReacTIONS OF STARVED LEECHES Leeches which had been starved for nearly two months were tested for their general responsiveness. Without the influence of external stimulation they tend to remain quiet for long periods of time even under the influence of a fair amount of illumination. When they are in this quiescent state, often several stimulations of the anterior end are necessary to produce a decided response. Upon their being awakened their response shows an increased irritability over that of the normal speci- mens, often upon the second or third stimulation the animal responding with a complete recoil and swimming reaction. In this excited condition only a very slight stimulus is necessary to set the leech wildly active again. The starved leech seems to be more easily fatigued upon the application of successive stimuli than is the case with the normal individuals. This is due perhaps to much the same reason as the similar phenomenon in higher animals. Lee (1910) says: ‘‘Exact laboratory investigation shows that if most of the carbohydrate be removed from an animal’s body, he presents the symptoms of pronounced fatigue ; TABLE XVI DURATION IN SECONDS OF SWIMMING RESPONSE IN NORMAL AND WELL-FED LEECHES Well fed leeches Normal leeches Order Number of individual Number of individual of stimu- — A ~ lation 1 2 3 4 5 Average 1 2 3 4 53 Average 1 2 3 3 3 4 3 b) 5 5 6 7 5.6 2 2 4 2 6 5 3.8 10 5 13 8 12 9.6 3 4 3 4 AeA: 3.8 10 10 8 10 14 10.4 4 8 3 4 2 3 4 12 11 4 10 15 10.4 5 15 4 5 &) 2 5.8 8 6 7 9 10 8.2 6 ayy 5 10 2 8 8.4 if 12 10 25 9 12.6 tf 9 @ dil 6 3 6.4 4 11 12 21 15 12.6 8 11 2 5 by “al a 5 8 22 10 8 10.6 9 30 8 8 4 8 11.6 15 12 17 10 10 12.8 10 50 6 3 2 3 12.8 10 5 14 5 13 9.4 11 10 5 6 5 4 6 8 6 8 7 10 7.8 12 10 3 5 6 7 6.2 10 12 18 12 10 12.4 13 3 4 3 5 3 3.6 7 9 35 18 15 16.8 14 5 2 6 4 13 6 10 6 12 15 10 10.6 15 6 3 8 6 4 5.4 15 13 15 8 9 12 292 University of California Publications in Zoology [Vou. 11 and the same is true of his individual muscles, which are ineap- able of performing as many contractions as the muscles of a normal animal.”’ As has been stated in the first part of this paper, leeches starved for almost six months show considerable vigor of re- sponse. This fact is indicated very clearly by the accompanying curves (see fig. 13) of activity of normal and starved animals. These curves are plotted from forty responses to contact stimu- lation of the posterior end, and consequently represent only the initial stages of a complete curve of activity. Proportionately the starved specimens show a greater irritability than the normal specimens. The relative nature of the curves seems to indicate that the starved leeches would reach complete depression with a smaller number of stimulations than would the normal speci- mens. 3. RESPONSES OF UNDISTURBED LEECHES There is in the behavior of the leech a condition corresponding to that of ‘‘sleep’’ in the higher animals. In this state the animal may occupy one of several positions. It may have the anterior eighth of the body turned back over the rest of the body ; sometimes it may be coiled slightly; and again, the body may be held entirely straight, the animal hugging the bottom of the dish. In this condition two or more stimuli are necessary to arouse the animal to action. The first stimulus when the leech is in this condition may produce little more than a local con- traction; the second, a turn to the left or right as the case may be; while the third will produce a reversal of direction of the anterior end together with swimming. This type of response is just what would be expected in summation effects of stimulation, and this is doubtless the true explanation for the behavior. When the animal is awakened the responsiveness is sharp and vigorous. A slight stimulus of the anterior end may produce a reversal of direction of orientation and subsequent swimming. This would indicate a heightened tonus for the body of the animal as the result of its period of rest, the stimulus liberating a greater supply of energy than normally because of the replenished stores of energy producing material in the tissues of the body. 40 Cocco { t SEeCEEEEEe a a Fig. 13.—Curves showing the comparative responsiveness of normal leeches and leeches starved for six months. Dotted line responses of normal leeches; solid line, the behavior of starved leeches. represents 294 University of California Publications in Zoology [Vou.11 TABLE XVII DIFFERENCES IN SECONDS IN RESPONSIVENESS BETWEEN LEECHES STARVED FOR APPROXIMATELY Starved specimens A Srx Monrus anpD NorMAL INDIVIDUALS Ti Ir im oy ww 2 2 15) 4 10 2 43) 1.5 3.5 6 6 16 15 3 2 4 3 3 B45) 3 2 4 33 3 10 4 1 5 b) 18 5} 6 2.5 5 4 11 2 2.5 1.5 9 8 15 2.5 9 2 7 4 7 6.5 3 3.5 5 16 7 4.5 4 2 3 9 6 UBpay 718} 2.5 9 (35 15 “i 6 3 8:5: 5 13 38 4 a U5) 3 7 12 83 ) 2.5 4 8 14 52) 6 by 5 16 9 24 3 3345) 12 5 6 2 5 3 8 6 5 197 3.5 2 6 4 7 84 1 2.0 7 7 10 27 2 3 4 14 14 88 6 4 8 16 3 24 3 6 10 7 8 28 11 5 8 14 23 34 3 4 7 18 19 74 4 5.5 15 21 20 36 3 3 55 13 13 24 3 9 14 5 4 53 4 3 11 9 5 38 9 3 116) 47 8 33 13 7 8 11 5 34 8 5 PAs 8 23 2 5 2 90 8 9 62 19 6 6 14 14 5 8 5 25 38 13 41 3) 4 57 5 14 46 a3 5 56 19 18 39 4 7.5 15 15 8.5 47 5 4 97 8 24 27 13 5 6 17 13.5 3 5 5 55 11 12 Average 3.6 5.9 2.8 By! Tel! 5.6 6.3 5.3 6.8 4.8 I 10 16 13.5 12 17 10 16 8 13 Normal specimens ht bet DO DO wnroan @ bo Tit 6 16 6 11 16 20 16 17 IV 8 a AJawrupwwrne 4 is i) 10 Average 13 10.1 8.9 13.3 18.7 13.2 13.5 28 24.8 13.8 12 10.1 13.2 11 15 11.7 10.5 11 7.2 15.2 18.6 12.5 17.3 16.5 28 ile 15.5 aly(ell 12.5 14.7 20.3 22.3 21.3 14.5 14.5 19.3 23.5 33.7 24.5 42.5 1913] Gee: Behavior of Leeches 295 The general responsiveness of the leeches in normal, starved, and well-fed states indicates the influence that metabolic condi- tions may have upon the reactions of the animal which has formed the subject for this investigation. The effect of feeding to satiety seems a generally depressing one, perhaps due, as has been shown in the case of fatigue, to substances produced in the body tissues of the animal incident to its digestive processes. In this con- nection an idea of Lee (1910) is highly suggestive: ‘‘It is im- possible to avoid a strong suspicion that the presence of a super- fluity of foodstuffs within the body leads to an accumulation of intermediate metabolic products which in themselves act on the tissues as fatigue substances.’’ In the starved condition, the animal has remained quiet sufficiently long for the system to have become largely rid of such substances, and at first is some- what low in responsiveness. As the fatigue substances increase, irritability is increased to the stage where the accumulation of these substances and the depleted stores of energy furnishing materials cause depression to set in. VIII. GENERAL CONSIDERATIONS ON MODIFIABILITY IN LEECHES Much stress has been placed in recent years upon the great variability of reactions in organisms. Not only has there been shown in numerous instances marked differences in the behavior of different individuals of a particular species, but there have been demonstrated wide variations in the responses given by the same individual to a particular stimulus at different times. This variability of reaction has been shown to be largely due to in- ternal changes in the animal. Attention has been directed quite properly towards this plastic element in an organism’s respon- siveness; for the work which has been the outcome of the pro- jection of such a view has served to place the behavior of an animal in its true perspective. Far from projecting the analysis of behavior into the realm of vagueness and mysticism, it has only made more apparent the fact that the problem of this analysis is one much more complex than was formerly supposed. The most interesting and significant feature in animal be- havior is the regulatory nature of the responses. The fact that 296 University of California Publications in Zoology [Vou. 11 a living organism can within certain limits adjust itself to the varying factors in its life-complex is its own peculiar charac- teristic. Yet even here there is a limit to the element of plas- ticity ; perhaps the moth, unless it changes its physical make-up, will ever be doomed to meet death about an are-light or a trap lantern. Not all behavior is adaptive in character, and partic- ularly is this true when the animal is placed amid the factors of a new environment. In the words of Wasmann: ‘‘Both elements, automatism and plasticity, are found in different pro- portions with all animals from the highest to the lowest.’’ Modi- fiability in the behavior of animals, generally, falls into two categories: (1) modifications of reflex responses without the inter- vention of intelligence, and (2) the intelligent modifications, or those effected through the power of association formation. In the study on leeches presented in this paper, only the first of these types of modifiability has been considered. The random movements of the leech afford an excellent illus- tration of the function of modifiability in a lower organism. Illumination of a fair intensity seems to interfere with the normal processes of the leech. When it is subjected to light of 100-watt intensity random movements are the response immedi- ately given by the organism. Through these the leech is enabled to locate finally a region of lower light intensity in another part of the dish. Through the same agency the leech succeeds, after numerous trials, in locating its food, as well as in performing numerous other features of its daily life. In the lower organisms modifiability plays the rdle largely assumed by intelligent action in the higher animals. The analysis of this modifiability is very largely facilitated through the principles already demonstrated in the higher ani- mals by such able workers as Sherrington (1911), Lee (1907, 1910), and numerous others. Whatever merit this paper on leeches may have is due, in the opinion of the writer, to the fact that its chief attempt has been to determine to what extent these principles are manifested in the behavior of the leech. While no one can be more fully aware than the writer of the imper- fection of the methods employed in many of the experiments and the inadequacy of the data presented in support of certain con- 1913] Gee: Behavior of Leeches 297 clusions, still the aim throughout the second part of this paper has been to present, so far as possible, a causal explanation of the behavior described. The different responses to the same stimulus have been shown in their essential features to be in accord with our knowledge of reflex-are structure and what might be expected of its conduc- tivity in the various stages of excitement of the leech. oe roy, ene \ = CS Nes ‘ = sup. conn. tis._ - 53> Wl PLATE 15 Polyorchis penicillata Fig. 8. Ocelli from the same medusa showing the distribution of pigment on different tentacles. The darker spot is the brown pigment at the center of the ocellus. X 14. Fig. 9. Pigmentation of a weil-developed ocellus. The darker cen- ter is the brown pigment of the ocellus. The red pigment extends peri- pherally from this but especially upward upon the bell and downward upon the tentacle. X 60. Fig. 10. A single large red pigment mass. X 666. Fig. 11. Pigment-bearing cells of the ocellus. a. Isolated epithelial cells with red pigment. b. Epithelial cell without pigment. X 1300. Fig. 12. Isolated ganglion cells from the epithelium of the tentacle near the ocellus showing interlacing of ganglionic processes with the muscle fibers. XX 1300. Fig. 13. Same showing distal branching of ganglionic processes. Fig. 14. Isolated nerve cells from the base of the ocellus of bipolar and multipolar types. [328] [LITTLE] PLATE 15 UNIV. CALIF. PUBL. ZOOL, VOL. II SOB Acer, 55 RSS % ‘ete 10 UNIVERSITY OF CALIFORNIA PUBLICATIONS IN ZOOLOGY Vol, 11, No. 3, pp. 329-376, pls. 16-20 March 21, 1914 MODIFICATIONS AND ADAPTATIONS TO FUNCTION IN THE FEATHERS OF CIRCUS HUDSONIUS BY ASA C, CHANDLER UNIVERSITY OF CALIFORNIA PRESS : BERKELEY UNIVERSITY OF CALIFORNIA PUBLICATIONS Note.—The University of California Publications are offered in exchange for the publi- cations of learned societies and institutions, universities and libraries. Complete lists of all the publications of the University will be sent upon request. 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Publ. Zool. Volume 1, 1902-1905, 317 pages, with 28 plates. oc... cece cece cscceccacndacesoesicvenwenteneeeed $3.50 Volume 2 (Contributions from the Laboratory of the Marine Biological Associa- tion of San Diego), 1904-1906, xvii + 382 pages, with 19 plates Volume $8, 1906-1907, 383 pages, with 23 plates 0c... jcedccsseeccecenscuseeeseserascossdbennenseens Volume 4; 1907-1908, 400 pages, with 24 platés : Volume 5, 1908-1910, 440 pages, with 34 plates Volume 6, 1908-1911, 478 pages, with 48 plates : Vol. 7. on pare from the Museum of Vertebrate Zoology.) 1. Two New Owls from Arizona, with Description of the Juvenal Plum- age of Strix occidentalis occidentalis. (Xantus), by Harry S. Swarth. ee PD Al -B5 ASME O10 es Gn Saree Eas ees cage 10. 2, Birds and Mammals of the 1909 Alexander Alaska Expedition, by Harry 8. Swarth. Pp. 9-172; plates 1-6; 3 text-figures. January, 1911. 1.60 8. An Apparent Hybrid in the Genus Dendroica, by Walter P. Taylor. BD LIBEL SE CDTUALY, SAO Ar Re seeks eee ee rected 05 4, The Linnet of the Hawaiian Islands: a Problem in Speciation, by = Joseph Grinnell. Pp. 179-195. February, 1911 ~.2.2 2.0.22. 15 5. The Modesto Song Sparrow, by Joseph Grinnell. -Pp. 197-199. Feb- BUALY CLOT se a aS ee rs acess eae pean .05 6. Two New Species of Marmots from Northwestern America, by H. 8. Swarth...Pp. 201-204. «February, 1911 occ. e cect agen cman 05 7. Mammals of the Alexander Nevada Expedition of 1909, by Walter P. Taylor.< Pp. 2052307. Se, LOE eo pacman act lone gps taigenwantononee 1.00. 8. Description of a New Spotted Towhee from the Great Basin, by J. | Grinnell. Pp. 309-311. August, 1910 2... ce ccc een cettnnenceceecnneenae 05” 9. Description of a New Hairy Woodpecker from Southeastern Alaska, by eit H. 8, Swarth. Pp. 313-318. October, 1911 .2.c2ccnec.eceepect eet tse 05 i 10. Field Notes on Amphibians, Reptiles and Birds of Northern Humboldt - =. County, Nevada, with a Discussion of Some of the Faunal Features ete of the Region, by Walter P. Taylor... Pp. 319-486, plates 7-12. ~~ GDIUBTY, LOD oes aaa ac a reeecnnn sesaee armeaneg can teteh cee sepece onder cedbasaseareasncssssbenseve 1.00.” Index, pp. 437-446. : 1, aE Vol. 8. 1. The Vertical Distribution of Hucalanus elongatus in the San Diego : Region during 1909, by Calvin 0, Esterly. Pp. 1-7.. May, 1911 ........ 10. 2. New and Rare Fishes from Southern California, by Edwin Chapin Starks and William M..Mann. Pp. 9-19, 2 text-figures. July, 1911. 10. ; 8. Classification and Vertical Distribution of the Chaetognatha of the San - Diego Region, Including Redescriptions.of Some Doubtful Species of rare the Group, by Ellis L. Michael. Pp. 21-186, pls. 1-8.. December, 1911. - 1.75 ea 4, Dinoflagellata of the San Diego Region, IV. The Genus Gonyaulax, with — ase Notes on Its Skeletal Morphology and a Discussion of Its Generic and Specific Characters, by Charles Atwood Kofoid. 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UNIVERSITY OF CALIFORNIA PUBLICATIONS IN ZOOLOGY Vol. 11, No. 13, pp. 329-376, pls. 16-20 March 21, 1914 MODIFICATIONS AND ADAPTATIONS TO FUNCTION IN THE FEATHERS OF CIRCUS HUDSONIUS BY ASA C, CHANDLER CONTENTS = PAGE Introduction Pterylography IMoults: Sees se ee ee eee Down Feathers 25 Ord amy, DO Wi 2 2scocc sense sses sop co bsncose nme eee ee sore ae a ons aas ten eccccncccxcace 332 Dow; LSAT) Oy inn eee oven sonnet con acta see coe ee RP vt Aer ae 333 GOiltGlandtMea thers) < 22... 2.5 e eee ee re em Sees 334 SRT OP UUM OS pe secre a coat Sn Soe ga ae nn cece ne ee eae ee 334 IRON DES). ceva se sw secn ease a a en eee ae en ere ge re REO) ee 336 INESCTOSCOPL Cie LLU C LUT O ee access casero tes med eee ese ae a 336 INI CTOSCOPICHS TRU CULO) ents ces cane aces cee ee eee ee 340 DAU COL 05 i ee ee ee Oe 344 Greater Upper Coverts .. 344 Greater Under ‘Coverts| 22--.-...---.----- ... 345 iMiddlesamd@bessersUippenr (Covierts jc ccrce erect enero 346 FEROS pete c rere servant Oe Doe a oe 347 Middlesand slvessersUmnders Comertsrc--sesee cece ern ae ee 347 PAT Ui ea ape et seen eee ck oe ete ee ore as DRG eee eee ety Beier et 348 TR CLIT COS re ence ca see rc PUY Cera, Se gree US est oh 350 Contoureheathersnote sti ew ruin Kagee esa eee eee ge ne ea ne ee os 352 QOS} 09 oY SS Pa See nee oer ere Ra eee ee ee 352 Winder d Parts gecee scene che ue ee ne se ee Oe, ee 354 Modified Feathers of the Head .. Petre recente ie eee it/ acral pRiuthees see ae a CDE aR Ov. ents yee sce ek ee ees ee ee he ee = 308 Post- and Supraorbital Bristles —.......2..-...--..-10-.--- -. 399 Dh EM EASV ANCES) econ teed eee eS eee SE nm ne Soa 359 Moraleandmhiccalebrast lessee ecse anne eee anne Nene ERE NE 360 Cone] sions ieee sen ocean ter Are Se ae Ad a Las ea ALR Ae 361 abiiysyematheey AO pn nots cere eee ote rene Sere cl ene eee tee ee ee 366 nian Insti; ig “io, 330 University of California Publications in Zoology [Vou. 11 INTRODUCTION As preliminary to a study of the modifications and evolution of feathers in the various orders and families of birds, it seemed desirable to ascertain the range of variation and degrees of development displayed in the plumage of a single bird. In the selection of a species to use for this purpose, it was decided to employ one which would show as great a number as possible of ordinary types of feather modification. A brief survey of the available birds to use for this study showed that of all North American birds the Marsh Hawk, Circus hudsonius (Linnaeus), combined the greatest number of ordinary feather types. It possesses strong and highly developed flight feathers, well- developed tail feathers, body feathers with aftershafts, rictal bristles, eyelashes, ear-coverts, facial ruff, an oil-gland tuft, powder-down patches, ordinary down, and filoplumes. The specimen used for the greater part of the work is number 11942 of the University of California Museum of Vertebrate Zoology. It is an adult female, taken at Riverside, California, November 2, 1887. The most superficial glance at such a bird is sufficient to show that there is a very great difference in the structure of its various kinds of feathers. The stiff, strong flight feathers are not less unlike the soft, fluffy belly feathers than are these unlike the hairlike bristles about the mouth and eyes. Indeed it may be stated that nowhere in the vertebrate phylum can a greater diversity of integumentary structures be found on a single indi- vidual than on such a bird. That such a variety of structures, varying as widely in function as in form, should be reducible to a single type of integumentary growth, similar in origin, development, and fundamental structure, is truly remarkable. A study of the modifications which are involved in producing this variety of form, and the extent of these modifications in feathers of various parts of a single bird’s body, is the object of the present paper. Most grateful acknowledgments are here ex- tended to Professor C. A. Kofoid, of the University of California, for his kindly aid and supervision, and to Dr. Joseph Grinnell, of the Museum of Vertebrate Zoology of the University of Cali- fornia, for his generous co-operation in the supply of material. 1914] Chandler: Feathers of Circus hudsonius 331 PTERYLOGRAPHY Before entering into a discussion of the structural modifica- tions in the feathers of Circus hudsonius, a few words about the general pterylography of the genus will not be out of place. In common with the Accipitres in general, Circus is character- ized by the presence of aftershafts, a permanent covering of down feathers not confined to tracts, and a cirelet of feathers at the apex of the oil gland. In working out the pterylosis of various accipitrine birds, Nitzsch (1867) stated that the general pterylographie characters of C. pygargus (= cyaneus?), C. aeru- ginosus, and C. cinerarius (—cineraceus?) essentially agree with those of Milvus, Pernis, and Astwr, especially in the narrow form of the tracts; in the presence on the dorsal portion of the spinal tract of two divergent rows of feathers which reach the scapular fork; in the small size of the lumbar tract; and in the shortness of the inner branch of the inferior tract. Circus may be distinguished from the majority of the Acciptres (Elanus, Elanoides, Regerhinus, and Gypaétus excepted) by the presence of lumbar powder-down patches in two symmetrical tracts on the sides of the pelvis, the posterior portion of the spinal tract run- ning between them. Each patch tapers off anteriorly into a narrow band which reaches the shoulders. The tarsus is feath- ered one-third down in front, and is essentially naked behind, the head is fully feathered, the base of the gape is furnished with bristles, and the face is given a rather owl-like expression by the presence of a facial ruff. MOULTS An examination of about twenty-five skins in the University of California Museum of Vertebrate Zoology indicates that Circus hudsonius moults but once a year, this being in July. Three specimens showed new feathers in process of growth, one from San José, California, taken July 12; a second from Modoe County, California, at an altitude of 7000 feet, taken July 29; and a third from Kenai, Alaska, taken August 4. The two Cali- fornia specimens are in process of moulting both the definitive 332 University of California Publications in Zoology [Vou. 11 and the down feathers, while in the Alaska specimen the contour feathers have all been renewed, but the down feathers are still growing in, a fact which indicates that the down feathers are moulted slightly later than the contour feathers. The filoplumes are renewed concomitantly with the definitive feathers to which they are adherent. DOWN FEATHERS OrpDINARY DOWN As intimated above, the entire body of Circus is covered with down feathers, this being a characteristic in which the diurnal raptorial birds agree with the water birds, and differ from the eround and perching birds, which, as adults, have down only in the apteria. The down feathers of Circus are practically uniform on all parts of the bird, though as a rule those occurring in the midst of the contour feathers are smaller than those in the apteria. The calamus is exceedingly short, considerably less than a millimeter long, and almost entirely buried in the skin. As is usual with birds possessing aftershafts, the down feathers, as well as the contour feathers, are furnished with aftershafts, though in this case the two shafts, on opposite sides of the umbilicus, are practically equivalent to each other. The division between the two shafts at the umbilicus may best be looked upon as a split in the quill, since the pith may always be seen pro- jecting for some distance in front of the division into shafts. As a rule, one shaft is somewhat longer and broader than the other, but this is as likely to be on one side of the feather, which projects at right angles to the body of the bird, as on the other, and it is not likely that this difference in size should be looked upon as significant of a differentiation of shaft from aftershaft. At the base the shafts of the down feathers are as broad as the diameter of the calamus, i.e., about 0.20 to 0.25 millimeters, but it decreases rapidly with each pair of barbs eiven off and entirely breaks up into barbs in from 3 to 7 milli- meters. The barbs are exceedingly numerous, being about twelve per millimeter on each side, or over six times as many as on an ordinary flight feather or covert. The barbs are extremely long 1914] Chandler: Feathers of Circus hudsonius SBS and slender, some of them reaching a length of 25 millimeters, with a diameter of only 0.02 millimeter. The barbules, aver- aging about thirty-five to thirty-eight per millimeter on each side, are so fine and slender as to be scarcely visible to the naked eye. Though they may reach a length of 4 millimeters, they are scarcely over .005 millimeter in diameter. The individual cells of the barbules are from 0.06 to 0.15 millimeter long, and often bear at their distal ends two tiny prongs, which are rudimentary barbicels. The result of the density and leneth of these barbules is a cottony texture of the feather, and a covering for the body which could hardly be improved upon for the purpose it serves. The innumerable slender barbules are so dense as to produce a waterproof covering, and yet the air spaces between the barbules render it practically a non-conductor of heat, thus affording a very efficient heat insulation. In addition to this, it has an entirely negligible weight, giving therefore a minimum of wear and tear and waste of energy and a maximum of efficiency. Powprr-Down The powder-down feathers in general structure closely re- semble the ordinary down feathers of the body, but are at once recognizable by their peculiarly matted appearance, due to the masses of powdery substance adhering to the barbs and barbules. The proximal portion of the feather is most heavily laden with the substance, and, in addition, the barbs and barbules are always imperfectly differentiated, remaining partially fused as in a erowing feather. There is no evidence of the tips of the barbs or barbules breaking down to produce the powder, as stated by Pyeraft (1910), and the fact that the powder is most abundant near the base of the feather would further militate against this view. Nitzsch (1867) suggested that the powder was continually poured forth from the open end of the calamus, but this does not seem probable. The most probable explanation, it seems to me, is that a considerable portion of the feather germ, instead of developing into barbs and barbules, is stimulated by some unknown eause to break down into a fine powder, which adheres to the barbs and barbules, often in regularly shaped oval masses, 334 University of California Publications in Zoology (Vou. 11 holding together several barbs or barbules. Probably just as much of this powder is produced with the part of the feather first formed as with the later part, but due to the spreading out of the feather, and the using up of the powder, it has a less dense appearance. In powder-down feathers the barbs are attached more or less evenly entirely around the umbilicus, thus differing from the ordinary down feathers, which always have a distinet though short shaft on either side. O1L-GLAND FEATHERS A further modification of the ordinary down feathers is to be found in the “‘tuft’’ of the oil gland. On close examination this tuft is found to consist of a single circlet of feathers, four- teen in number in all three of the specimens in which they were counted. The calamus of these feathers, which is about one milli- meter long, is entirely imbedded in the skin. The majority of the barbs, about twenty to twenty-five, spring from the umbilicus in small groups of two to four, i.e., the calamus breaks up into a number of short roots, which almost immediately break into from two to four barbs. There is developed, however, on one side of the quill a single shaft which is very short and rudimentary, but nevertheless a constant feature. The barbs reach a length of approximately one centimeter or less, and bear a series of short, undifferentiated, awl-shaped barbules, averaging 0.54 mil- limeter in length, and inserted about fifteen per millimeter on each side. These barbules, differing so greatly in length from ordinary down barbules, differ further in that they he quite closely appressed to the barbs, instead of spreading. The func- tion of this circlet of small feathers, which is lacking in many groups of birds and is so characteristic of others, is quite unknown at the present time. FILOPLUMES Filoplumes, though nowhere overdeveloped or conspicuous, are found in considerable numbers at the base of the contour feathers of the dorsal, lumbar, and caudal tracts. These peculiar 1914] Chandler: Feathers of Circus hudsonius 335 feathers grow out in little bundles of from five to eight (pl. 16, fig. 2) on one side of the calamus of the contour feathers, and they le on the dorsal side of the feather to which they belong. Invariably the filoplumes of a single bundle vary greatly in length, ranging from 2 or 3 to 40 millimeters, usually no two being of the same length. The longest ones found were attached to the posterior row of under tail coverts. They are exceedingly slender, being from 0.03 to 0.05 millimeter in diameter, and entirely unbranched and unmodified up to the last few milli- meters, which may simply bear a series of barbules, or may break up into two or three barbs, each with its own barbules (pl. 16, fig. 1). The barbules, which are widely spaced, there being eight to fourteen per millimeter on each side, are entirely unmodified and comparatively rigid, although filamentous and somewhat over a millimeter long. The macroscopic appearance of these feathers is like a miniature ecat-tail reed, the long shaft, slender as a spider’s thread, corresponding to the stem, and the barbuled tip representing the ‘‘cat-tail’’ itself. What function can be served by these feathers is quite inexplicable, as they appear too weak and sparse to be of any possible use. As observed by Pyeraft (1910), filoplumes are degenerate feathers, each one, before development is complete, being sur- rounded by a number of barbs. In Circus some of these barbs appear never to spread apart and become fully differentiated as in Pyeraft’s figure, but they remain incompletely formed, em- bracing the shaft of the filoplume. Pycraft intimates that this shaft is merely a stronger persistent barb, comparable to the barbs which ultimately disappear, but it should rather be looked upon as a true shaft since barbs are never branched. It is probable that the barbs which are lost belong to the shaft, but through a defect in development never become attached to it. While developing, the tuft of five to eight filoplumes with their incomplete barbs appears like a single feather germ, but their roots are entirely independent of each other. The filoplames do not lose their deciduous barbs until some time after the contour feather has reached its full development and ceased to grow. 336 University of California Publications in Zoology (Vou. 11 REMIGES Macroscopic STRUCTURE The most highly specialized and most important feathers of the entire body are the remiges, or flight feathers, composed of the two groups, primaries and secondaries, the former borne on the hand, the latter on the forearm. Circus hudsonius is a bird of strong flight, and though not known to sail or soar to the extent of some of its aquiline and buteonine relatives, it is very graceful on the wing, combining in its usual mode of progression a buoyant, easy gliding, with occasional series of long, strong wing strokes. Though not indulging in it as frequently as many of the buteonine hawks, the harriers are capable of a similar spiral sailing. It is a migratory species, undertaking flights of long duration in the spring and fall. As might be expected of such a bird, the flight feathers are very highly developed and specialized. There are ten primaries and fourteen secondaries, which produce a long, ample, moder- ately pointed wing, with a comparatively shallow concavity from front to back. The wing is approximately of the same relative size as is that of Buteo, but is somewhat more pointed. This is due to the fact that the third and fourth primaries are con- siderably the longest, with the second and fifth next, equivalent to each other, while the first primary is somewhat shorter than the sixth. In the more rounded wing of Buteo the third, fourth, and fifth are nearly equal, while in the more pointed wing of Falco sparverius the second and third primaries considerably outdistance the others. The third primary, one of the longest ones, may be described advantageously as a typical primary, the points wherein the others differ from it being dealt with subsequently. The total length of the feather is 286 millimeters, of which 47 form the calamus. The latter is not quite circular in section, measuring 3.68 millimeters in diameter in the plane of the vanes, and 4.34 millimeters in the plane at right angles to them. It tapers suddenly at the root. A short distance above the superior 1914] Chandler: Feathers of Circus hudsonius 337 umbilicus there is a decided bend in the entire feather in the direction of the inner vane, and there is an even curve toward the under surface, somewhat increased at the tip, where the vanes are also somewhat rotated on their axis to comply with the different physical forees which come into play at the tip of the wing, and to permit the free passage of the air during its up-stroke. The points of origin of the rami of both vanes have a common beginning on the lower surface at the superior umbilicus, and proceed in an even curve toward the dorsal surface, coming to the plane of the upper surface of the shaft at about the proximal fourth of the vanes. The shaft is quadrangular in cross-section, becoming so immediately on the under surface, but remaining rounded on the upper surface to the point where the origin of the barbs reaches the dorsal surface. At this point the shaft measures 2.8 millimeters on the under surface, 1.86 millimeters on the upper surface, and approximately 3 millimeters in depth, taper- ing evenly from here to the tip. The under side is grooved in the middle for almost its entire length. As is usual with birds having highly developed flight, the vanes of some of the primaries are incised, i.e., abruptly nar- rowed toward the tip. On the inner vane of the feather this involves no change except the shortening of the barbs, and a slight decrease in the angle made with the shaft, but in the outer vane the character of the barbs is considerably changed beyond the point of incision. The angle made with the shaft is reduced from over 40 degrees to about 7 degrees, the intervals between origins on the shaft being thereby much increased, so that whereas about eighteen or twenty barbs per centimeter spring from the shaft on each side proximad to the incision, distad to it there are only four per centimeter. In addition to this, the ramus is increased in depth, and correspondingly in strength, to such an extent that while the dorsal surface of the barb is in the same plane with the dorsal surface of the shaft, the ventral surface, at the point of origin, is in the same plane as. the ventral surface of the shaft. The barbs of the outer vane are thus rendered very stiff and elastic, and hold their place, even 338 University of California Publications in Zoology |Vou. 11 if deprived of their barbules. A closer examination shows that all but the most proximal rami of both vanes, at their junction with the shaft, are continued to the ventral surface of it as more or less distinct ridges, suggesting that the stiff, broad, type of barb may be the more primitive, and that the form of the outer vane beyond the point of incision may be merely a reversion to an old type, rather than a new structure. As these barbs are serviceable without barbules, this condition might be thought of as a possible intermediate condition between a reptile’s scale and a normal feather, at a time when its evolution was taking place and barbules had not yet reached a perfected state of development. From the point of view of ontogenetic development, it is easy to think of the deep type of ramus as more primitive than the shallow one. At a time when shaft and barbs are mere ridges on the inner surface of the feather germ, the shaft ridge is probably to be considered merely as a number of barb ridges combined, as deseribed and figured by Strong (1902, p. 160, and pl. 1, fig. 2). This bemg the case, the more primitive condition would be that in which the barbs and shaft are of equal depth, as in the case of the comparatively primitive feathers of casso- warlies and penguins. In the latter the very broad, flattened shafts, while higher in the middle than the barbs, slope off on the sides, and there is no disparagement between depth of barb and shaft at their junction. In this case, however, the similar depth is due not to the greater depth of the barbs, but to the shallowness of the shaft. In the majority of ordinary feathers, where the shaft is enlarged and deepened, the barbs have not kept pace with this increase, and are therefore not so deep as the shaft. In the terminal portion of the primaries of Circus and other strong flyers, as shown above, there is a re-establish- ment of the equivalence in depth of barb and shaft, but whether this is to be considered as a reversion, or as a new specialization, depends upon the point of view. The inner vane is very much broader and better developed than the outer vane, its surface constituting over eighty-five per cent of the entire surface of the feather. There are no downy barbs whatever, except a few which spring from the lips of the 1914] Chandler: Feathers of Circus hudsonius 339 superior umbilicus. The incision comes at a point slightly over half way to the tip, and reduces the width of the vane from 26 millimeters to 16 millimeters. Beyond the incision there is no tapering until the tip is approached. The outer vane, as a resistant surface, begins about 25 milli- meters beyond the superior umbilicus, since the barbs proximal to that point are downy in character, and do not adhere to each other. The vane is 10 millimeters wide at its widest point, from thence slowly tapering before the sudden narrowing at the point of incision, beyond which it is only 3 millimeters wide. Proximal to the incision the barbs are 16 to 18 millimeters long, and set at an angle of 45 degrees; distal to it they are 24 milli- meters long, and set at an angle of 7 degrees, the transition taking place in about one centimeter. All of the first five primaries are very similar to the one described above, practically the only difference being in size, and in extent of incision. The first, which is the smallest of the five, 180 millimeters in total length, is most sharply curved toward the inner vane, and has the most extensive incision, especially the outer vane, which has barbs typical of the incised portion for its entire length, except a very insignificant area of normal barbs at its base. The inner vane is incised for approxi- mately one half its length. As the shaft is not so stout as in the third primary, the barbs of the outer vane are not so heavily built, and are set somewhat closer together, there being six to a centimeter, instead of four. The second primary is in every way intermediate between the first and third. The fourth differs from the third only in the less extent of its incisions. In this feather the wide portion of the outer vane for the first time exceeds the narrow portion, while the inner vane, though nar- rowed, has not so sharply demarcated a point of incision. The fifth primary has these characteristics emphasized, the outer vane being only about one-third narrow, and the inner vane beginning to taper rapidly at the point where the incision would be expected, instead of becoming abruptly narrowed. The remaining primaries, numbering six to ten, differ from the others in their uniform width, and in the sharper angle of the bend of the shaft toward the inner vane. From the sixth to 340 University of California Publications in Zoology (Vou. 11 the tenth primaries there is a gradual shortening of the feathers to 182 millimeters in the tenth, together with an emphasized curvature of the shaft, and an increasing amount of poorly developed vane at the base. The secondaries, of which there are fourteen, show a gradual _ transition from the outermost to the innermost. The first one is scarcely distinguishable from the last primary, the chief differences being in the more slender shaft, and in the intensified curve toward the inner vane. The tip of the feather is more broadly rounded than is the ease with any of the primaries. The first eight or nine secondaries, though very similar to each other, decrease in size to 160 millimeters in the eighth, and have increasingly slender shafts. Beyond the ninth secondary the transition from primary to covert type of feather becomes more rapid. The pronounced curve toward the inner vane is gradu- ally lost entirely, the shaft becomes very slender and flexible and the vanes become more and more equivalent in size, until in the fourteenth they are practically equal. As is very frequent among birds, the fifth secondary is absent, although its ecoverts are present. Microscopic STRUCTURE The minute structure of the barbs and barbules, as might be expected, is at its highest development in the remiges. As an example, let us study a barb from the wide portion of the inner vane of the third primary. We find that in a superficial way the barb resembles a complete feather in its structure. The ramus is a thin lamella about 0.46 millimeter deep at the base and gradually tapering toward the tip. The proximal ‘‘vane’’ of barbules, if such it may be ealled, is 0.16 millimeter wide; the distal vane, measuring to the tips of the barbules, 0.40 milh- meter. While the distal vane springs from the dorsal line of the ramus for its entire length, the proximal vane slopes down as it approaches the base of the barb, so that at its junction with the shaft it arises from a place about half way down on the ramus. The number of barbules per unit of measure gradually decreases from the base to the tip of the barb, very rapidly 1914] Chandler: Feathers of Circus hudsonius 341 decreasing at the base, and then very slowly decreasing all the way to the tip. i — > a iv | if di UNIVERSITY OF CALIFORNIA PUBLICATIONS 1N ZOOLOGY Vol. 11, No. 14, pp. 377-510, pls. 21-24, 5 text figs. February 27, 1914 A DETERMINATION OF THE ECONOMIC STATUS OF THE WESTERN MEADOW- LARK (STURNELLA NEGLECTA) IN CALIFORNIA BY HAROLD CHILD BRYANT UNIVERSITY OF CALIFORNIA PRESS BERKELEY Pcs pee UNIVERSITY OF CALIFORNIA PUBLICATIONS Note.—The University of California Publications are offered in exchange for the publi- cations of learned societies and institutions, universities and libraries. Complete lists of all the publications of the University will be sent upon request. For sample copies, lists of publications or other information, address the Manager of the University Press, Berkeley, California, U. S. A. All matter sent in exchange should be addressed to The Exchange Department, University Library, Berkeley, California, U.S. A. OTTO HARRASSOWITZ, R. FRIEDLAENDER & SOHN, LEIPZIG. é g BERLIN. Agent for the series in American Arch- Agent for the series in American Arch- aeology and. Ethnology, Classical Philology, aeology and Ethnology, Botany, Geology, Education, Modern Philology, Philosophy, Geography, Mathematics, Pathology, Physi- Psychology, History. ology, Zoology, and Memoirs. | ZOOLOGY.—W. E. Ritter and C, A. Kofoid, Editors. Price per volume, $3.50. Commenc- ing with Volume Il, this series contains Contributions from the Laboratory of the Marine Biological Association of San Diego. Cited as Univ. Calif. Publ. Zool. Volume 1, 1902-1905, 317 pages; with 28 plates ac. c---cccc-csscocecsancseeencssnsinsesteseateveeee $3.50 Volume 2 (Contributions from the Laboratory of the Marine Biological Associa- tion of San Diego), 1904-1906, xvii + 382 pages, with 19 plates .......2 $3.50 Volume 3, 1906-1907, 383 pages, with 23 plates Volume 4, 1907-1908, 400 pages, with 24 plates Volume 5, 1908-1910, 440 pages, with 34 plates Vol. 6. 1. (XXIII) On the Weight of Developing Eggs. Part I, The Possible Significance of Such Investigations, by William E. Ritter; Part 1, Practicability of the Determinations, by Samuel E. Bailey. Pp. 1-10. OCGCO DET E908 a he adap aa ane 10 (XXIV) The Leptomedusae of the San Diego Region, by Harry Beal Cea . (XXV) The Ophiurans of the San Diego Region, by J. F. McClen- don. Pp. 33-64, plates 1-6..~ Duly, 1909 2c. cece ceccce cee spesccnatgceseenee 30 (XXVI) Halocynthia johnson n.sp.: A comprehensive inquiry as to —- the extent of law and order that prevails in a single animal species, > by Wm. E. Ritter.. Pp. 65-114, plates 7-14. November, 1909 |... 50° - on (XXVIII) Three Species of Cerianthus from Southern California, by H. B. Torrey and F. L. Kleeberger. Pp. 115-125, 4 text-figures. Dereijher 21009 as Se re ee 10 6. The Life History of Trypanosoma dimorphon Dutton & Todd,. by Edward Hindle, Pp. 127-144, plates 15-17, 1 text-figure.. December, $GOG EE ee ee ele Nt Re En 50 7. (XXVIII) A Quantitative Study of the Development of the Salpa Chain-in Salpa fusiformis-runcinata, by Myrtle Elizabeth Johnson. pi d45-178, arenes 1 90 Oe Es ean ce ape eerste 35 8. A Revision of the Genus Ceratocorys, Based on Skeletal Morphology, by Charles Atwood Kofoid. Pp. 177-187. May, 1910 -.-.. 2. 10 9. (XXIX) Preliminary Report on the Hydrographic Work Carried on by the Marine Biological Station of San Diego, by George F. McEwen. Pp. 189-204; text-figure and map. May, 1910 nonce eaecnaee 15 10, (3X) Biological Studies on Corymorpha. TII, Regeneration of Hy- ~ dranth and Holdfast, by Harry Beal Torrey. Pp. 205-221; 16 text- figures. 11, (XXXI) Note on Geotropism in Corymorpha, by Harry Beal Torrey. Pp. 223-224; 1 text-figure, Nos 10 and 11 in one cover. August, 1910 2s... cessive ceeseeneneen .20- 12. The Cyclostomatous Bryozoa of the West Coast of North America, by : Alice Robertson. Pp. 225-284; plates 18-25. December, 1910 ........... 60 18. Significance of White Markings in Birds of the Order Passeriformes, _by Henry Chester Tracy. Pp. 285-312. December; 1910 ..... 25 14. (XXXIII) Third Report on the Copepoda of the San Diego Region, by Calvin Olin Esterly. Pp. 313-352; plates 26-32. February, 1911 .. 40 15, The Genus Gyrocotyle, and Its Significance for Problems of Cestode Structure and Phylogeny, by Edna Earl Watson. Pp. 353-468; plates Rs CARES Sr Crees EW aps oe Bien Gey tic SE ces past eae PS SOY ea Saad ar 1.00 “Index, pp. 469-478. * Roman. numbers indicate sequence of the Contributions from the Laboratory of ths Marine Biological Association of San Diego. 7 POSED Torrey. Pp. 11-31, with 11 text-figures. February, 1909... ........ 20° Wouy A ee te ee Bee eS UNIVERSITY OF CALIFORNIA PUBLICATIONS IN ZOOLOGY Vol. 11, No. 14, pp. 377-510, pls. 21-24, 5 text figs. February 27, 1914 A DETERMINATION OF THE ECONOMIC STATUS OF THE WESTERN MEADOW- LARK (STURNELLA NEGLECTA) IN CALIFORNIA BY HAROLD CHILD BRYANT CONTENTS PAGE ATE La CO mate teeetebecnesecteeeree rae Sochecockcenenaetisee: borates seceresemtt ecco eat eee nee eeepee oe 378 TRATRROGI DOOR: ease entn sneskossbieeee cabeco nese shee eer Soc ee acta oe eet beer oer Re 382 History of methods in economic ornithology ..............2.-2...-----s-2sesseeeeeeeee 389 Investigation of the economic status of the western meadowlark nae Calliiih ONG aa eee ees aesn one certs pctv daananeaten saoetosaaiceictoasrer onsicrenedadnuebmeapancboeed 395 A comparison of methods in economie ornithology ~.......-......-...2.--.--.-.--- 397 The western meadowlark (Sturnella neglecta) .. Piel dipiriny, CS tab OM eerce een c reeset eater se ome ncaeacncecnencenens Boiler en homeo peer cn epee PNY OVINE TIRES Se ee Roe WNe Stim Na OUES 9 a2 cose ee cece sees ces cateeetcae seta cat censsecccseeeccugsteshescccassecedsvcsoestesesecs 404 Depredations ...... a5 mueeen OF BEX) CG GUNLE TGS MO NUN CAD Ulva DUNO S pet tevenetas ni stensneiss se sneteencctsdcaseeuseavoseerset covesuerenerte 409 PNTTECOAU ONE, COLE THAYOXG CT eCCKa UU CEG Sees An a Ere eee 410 MS PYILAAWEY (RES GUNS {SYS TKO Op ee de oe ee 412 Bxaminationuor therstomach (COmbe mts oo: csc -cccccecssecensc se cecasacscesesneeceneonesaoe= 413 Collection and preservation of material -...........2..2-..-22----22-eceeceeeeeeeeee 413 DME Rea ek eC eR eS Be RE ope PPE Se See EEEEEE 415 SB EREOULMeNLO De Oye St ONC Mt COTO IIDS esse ces eee eee cee 416 Ndentaticatiron of Stomach (com tents) ences a sce se se ene c ae dene eee can aeeemen on 420 Food of the western meadowlark in California .................. ogee see ees 420 NUAGEEREN EN ON CES ae Data es Ser eee eS Ee Ee ore 420 P\TaN WTS cr X06 Le Seek SERS oe Se ee 2 426 Nemo yea Ger GTO oe one estas cence ate eect cncetns Seek Se ees Caen ee eases 436 Principal articles of diet -........ adhe edit cn eee cep ere a cae aeesth 437 eG IT TE ZS In A v* fo / oi) 378 University of California Publications in Zoology (Vou. 11 Examination of feces Quantity of food Capacity for good or evil as evidenced by the number of birds taksim ditterent Wimids ot) LOO eee se a cence cee nce eee eames ne ABO O GTO faper1e ps Gin OS area ee ae eee ee eee Variation of kind of food Variation in food according to time of year Variation in food habits according to locality —.................... 454 Influence of age and sex on quantity of food ~..........222-2---2-- 455 Combination of field and laboratory work ............-.22.--.2.2-:.-::20sece-ee---= 456 The relation of birds to insect Outbreaks) ees esses cere ce emcees eee 456 Verdict of ranchers as to the value of the western meadowlark...... 462 A determination of the economic status of the western meadow- Janke im ‘Calitionmial) seis -ee es ceoceeecee eee acetone cee nena 466 Suggestions’ for the protection Of Crops: :...22:2c2-cecccs.ccececcessecesseeceasnene== 474 Recommendations as to legislation 22. ceeeccscec agen enn een ene ene ree mene eeeeeeeeenenene = 475 Some interesting side-lights on the investigation —......---.------ 477 Parasitism Malformation ARV ULSI sees so aa ees te eas cay conc ne ween ee oe The effect of systematic destruction on the numbers of meadow- larks : Natural death-rate Do protective adaptations of insects protect them from the at- back: ‘of pind sh) <8. - eS ee cen a ee ane eee 480 Availability as a factor in the kind and quantity of food of birds... 487 Solved and unsolved problems in economic ornithology ......................-- 488 SUMMIT. ices e coc ces cence casa eate secon cosas ens chases Soeee oes sooeet doses cee sce sea eee eee 490 Biblio grap ly. 225.2: cescese cote caccccedenececctcnescasnereceey ste casese=satee vacate wwe eeeeeee ee veete ae ne ceneees 494 Explanation of plates PREFACE The impetus given in late years to the study of the relations of birds to agriculture in the United States is traceable to the extensive work of the United States Bureau of Biological Survey. From the organization of this department of the United States Department of Agriculture, July, 1885, to December 31, 1911, members of the Biological Survey have prepared and published one hundred and thirty-one documents relating wholly or in part 1914] Bryant: Economic Status of the Western Meadowlark 379 to the food of birds. Notes on the economic status of over four hundred species of native birds and of over fifty species of foreign birds are to be found in these publications. In many cases extended studies have been made of the food of birds by the examination of stomach contents. In no other country has economie ornithology been aceorded the attention it has received at the hands of the United States Department of Agriculture. In a newly settled state like California, where large tracts of land are being brought under cultivation, disturbances of the natural order of bird life arise in two ways. First, the natural food supply of birds is destroyed through cultivation. Second, a new source of food is often supplied by eultivated crops. Hence birds become of great economic importance. The variety of conditions to be found in so large a state as California makes a study of these economic relations of birds complex and difficult. In spite of the need, therefore, of a knowledge of the value of birds, comparatively little work along this line has been done in this state. Until recently two bulletins entitled ‘‘Birds of California in Relation to the Fruit Industry,’’ by F. E. L. Beal, published by the U. S. Bureau of Biological Survey, and a few seattered notes in ornithological literature afforded the only pub- lished material on the economic relations of birds in California. Complaints of the depredations of birds in this state have been numerous. The injury to fruit caused by the linnet (Car- podacus mexicanus frontalis) is so great that this bird is branded as a pest by the fruit-grower. In recent years grain-growers have complained of damage to sprouting grain caused by western meadowlarks (Sturnella neglecta). These birds have been ac- cused, and rightly so, of boring down beside the sprout with their long bills and pulling off the kernel of grain. Ranchers have maintained that in some eases whole fields of grain have had to be reseeded because of the loss occasioned by these birds. In fact, there has developed so much sentiment against the meadowlark that there has been a persistent attempt made at each legislative session to take protection from the bird. As the western meadowlark is a bird defended by many because of its insectivorous habits, the agitation following the complaints has afforded an exceptional opportunity to deter- 380 Unwersity of California Publications in Zoology {Vou. 11 mine scientifically the economic value of this bird by a thorough investigation. Such an investigation has been made possible through the patronage of the California State Fish and Game Commission, which established a research fellowship in the De- partment of Zoology of the University of California. In Jan- uary, 1911, I was appointed Fellow in Applied Zoology on the Fish and Game Commission Foundation in the University of California, with instructions to carry on an investigation into the relation of certain California birds to agriculture. The com- mission assumed the expense and through its deputies furnished the material for stomach examination. The office work and the laboratory work have been carried on in the Zoological Depart- ment of the University of California. The investigation has. therefore, been conducted through the co-operation of the State Fish and Game Commission with the University of California. To the men past and present who have preceded me in this line of work and who have furnished the world with the under- lying facts which have established the science of economic orni- thology I wish to give due credit, for without their contributions this work must necessarily have been far more elemental. The helpful criticisms and valuable suggestions of Professor Charles A. Kofoid of the University of California, under whose direction the work has been done, have inspired and assisted me in the task. To Dr. Joseph Grinnell, Director of the Museum of Verte- brate Zoolegy in the University of California, who has often given me of his time to discuss certain features of the work, I owe much. The help also of Mr. E. R. Ong as laboratory assist- ant, and of Professor C. W. Woodworth, Dr. E. C. Van Dyke, Dr. F. E. Blaisdell, Mr. John Bridwell, Mr. W. L. MeAtee, Miss Anna M. Lute and others in the identification of insects and weed seeds has lightened the burden and facilitated this part of the investigation. Although collections have been made of a number of birds about which complaint has been received (western robin, bicolored red-wing, Brewer blackbird, horned lark, western mourning dove, and roadrunner), yet, because it was the special object of attack, effort has been concentrated on determining the eco- nomie status of the western meadowlark. 1914] Bryant: Economic Status of the Western Meadowlark 381 The investigation has consisted primarily of field investiga- tion, experimentation, and stomach examination. A large part of the field work has been carried on at Lathrop, San Joaquin County, California, a place admirably suited for the work in hand. Duties on the agricultural and horticultural demonstra- tion train, which toured the state in 1911 and 1912 under the auspices of the Department of Agriculture of the University of California and the Southern Pacifie Railway Company, have afforded additional opportunity to study conditions from one end of the state to the other. Economie ornithology is a new science and has hardly pro- eressed further than the stage of preliminary interest and study. As a result practically all of the work attempted thus far has been of the extensive rather than of the intensive sort, and has been made up largely of a study of the food of birds. In this investigation the attempt has been made to improve on past methods and, by determining the food of birds taken in the same locality each month, or twice each month, to furnish reliable evidence as to their food throughout the whole year. A study of the bird in the field, its depredations, and its hfe-history, has also been made in order that all available evidence might be obtained. Considerable difficulty has been experienced in that there has been, and now is, a difference of opinion as to the criteria to be used in the determination of the economie status of a bird. The ideas which have been advanced in the past, and even those of the present day, appear to be unsatisfactory, or at least un- trustworthy. It seemed, therefore, that a review of past methods, with the addition of such new ones as appeared to be valuable, might prove not only interesting but of considerable value to future workers in the field. A similar lack of information re- varding methods of stomach examination has been evident. A detailed account of the method used in this investigation, there- fore, seems justified. The service which birds render to agriculture has doubtless been overemphasized. On the other hand, the position taken by some that birds are of no value as insect and weed-seed de- stroyers hardly seems justified by the facts. If there be a mis- 382 University of California Publications in Zoology (Vou. 11 conception as to the utility of birds, it is high time we sought to destroy it and to establish truth in its stead. The economic relations of birds must necessarily become more and more important. As they do so, the extensive study of the past few years will give way to the intensive study necessary to solve the greater problems of the future. Probably no one thing will play a greater part in the conservation of wild life than will this intensive study. Recognition of the economic value of a single bird will stimulate interest in the protection of all. This work is published, therefore, in the hope not only that the facts and data here presented may be of general interest and of value to future workers in economic ornithology, but that it may be a factor in promoting the conservation of wild life in California, a state which still possesses enough of its original fauna to make its conservation important and eminently desirable. INTRODUCTION Doubtless if our knowledge were not so limited we might be able to find a use for most living things. As it is, we designate animals as useful, neutral, or injurious because of their effect on ourselves or our interests. A thorough study of the inter- relations of such animals often reverses our original decisions regarding them. Not many years ago insects as a class were called injurious because some of them destroyed certain crops. Today only a part of the insects are considered destructive, and we are yearly finding that others are of neutral or beneficial character. Not many years ago birds were looked upon either as pests or as marks for the gunner. Today most of them are looked upon as valuable assets of the agriculturist. As science in the past has slowly lifted us to a plane where we study the complex interrelations instead of the single and obvious ones, so in the future we may expect that more and more each form of life will be found to fill a particular niche in its environment better than any contiguous form. 1914] Bryant: Economic Status of the Western Meadowlark 383 And yet, viewed from the utilitarian standpoint, there is a certain value in classifying organisms as injurious or beneficial. The danger lies not in the classification itself, but in the risk attendant upon a judgment hastily made or one based on circum- stantial or partial evidence. Being the dominant form of life on the earth, it is only natural that we measure the usefulness of things by their immediate effect on ourselves or our interests rather than on the whole complex of nature. An intimate knowledge of the use of wild life is indispensable to sane conservation. Anything known to be useful may justly demand protection. Anything known to be of no utility in nature may justly be accorded destruction. Ignorance has caused the waste characteristic of the past. Knowledge must prevent waste in the future. What may not seem to be of use today may be of great importance tomorrow. It appears that the economic value of wild life seldom becomes evident until the form becomes extinct, or at least diminished in numbers. It was only a few years ago that fish were so abundant that no attention whatever was paid to their life-histories. Today the study of ichthyology, including fish-hatching, is a necessity, in order that the supply of this kind of food may continue to be available. Not many years ago people believed that there was an inexhaustible supply of game. Today strict game laws and the most careful conser- vation alone prevent the extinction of many forms. Fifty years ago the farmer in the east may have lost some grain and corn from the depredations of birds, but he either planted an extra acre or two to make up for the loss or took it as a matter of course. At the present time, however, when we find not only much of the available land under cultivation, but even that cut up into small tracts and men attempting to earn a living on ten or twenty acres instead of on eighty or a hundred, the depredations of birds are more noticeable. The loss of a sack of grain is hardly noticeable in a large field, but let the same amount be lost in a two- or three-acre field and the loss becomes relatively important and very apparent. It is only natural, therefore, that at the present time complaints against birds are more frequent and more insistent. 384 University of California Publications in Zoology (Vou. 11 Depredations probably increase also as the natural food sup- ply of birds is destroyed and they have to rely on the products of civilization. The change of food caused by change in enyiron- ment sometimes causes an increase in the number of birds of a species, and thus increases the extent of the depredations. Ap- parently there are a number of birds in California which have directly profited by the change of environment and are increasing in numbers. The linnet, western meadowlark, and mockingbird undoubtedly belong to this class. As the crops change, and consequently the food supply, we may even expect that in the future the food habits of birds will change. Hence a knowledge of the food habits of birds at the present time may be of far greater value in the future, when such data are needed for comparison. Whether it is best to destroy certain birds because of their depredations, or to preserve them because of their value as insect or weed-seed destroyers, has become a real problem. There is not a farmer who is not at some time of the year confronted with this problem. In a newly settled country the question as to the value of certain birds is often of grave importance. If nature were not so closely woven together we might easily solve the problem by simply exterminating those birds which cause damage. In the early days this was tried. It is experience that has taught us the danger attendant on the indiscriminate ex- termination of any form of life. The problem stated, the next thing to be considered is: How shall it be solved? Observation has proved an unsafe method of determining the true value of a bird. Mere sentiment fails to convince a large number of the class of people deeply interested from actual contaet with the problem. The method which has proved the most dependable is a thorough scientific investigation. The problem is complex. It involves a knowledge of the life- history of birds, inseets, and plants, a conception of the inter- action of organisms, and an appreciation of the accompanying ecological relations. A scientific investigation as a means of determining the status of a bird presents just as great possibilities as this method has in other fields. In preventive medicine we see the results of 1914] Bryant: Economic Status of the Western Meadowlark 385 scientific method. The efficiency of the forest service can be attributed to the same methods. If, then, this type of investi- gation can help us to conserve our health and our forests, it should also lead to the best method of conserving our native birds. Professor Charles S. Minot has defined the method of science as ‘‘the art of making durable, trustworthy records of natural phenomena.’’ He goes on to say: ‘‘The method of science is not special or peculiar to it, but only a perfected appleation of our human resources of observation and reflection—to use the words of von Baer, the great embryologist. To secure relia- bility the method of science is, first, to record, everything with which it deals, the phenomena themselves and the inferences of the individual investigators, and to record both truly; second, to verify and correlate the personal knowledges until they acquire impersonal validity, which means, in other words, that the con- clusions approximate so closely to the absolute truth that we ’ ean be safely guided by them.’’ These statements justify the use of scientific method for any modern problem and especially for the problem in hand. ‘“But putting aside economie and utilitarian considerations, there is to some of us a greater stimulus to solve the problems of nature. With the birds, and the insects and plants upon which they feed, we share a common heritage, and the more we learn of the life of these, our fellow-workers, the nearer we ap- proach solution of the great riddle of the Universe, the mysterious law-abiding scheme of Nature. The book of knowledge to which we add some iota is marred with mystery, superstition and error, but each proved fact cleanses its pages. ‘Facts,’ says Laing, ‘are the spokes of the ladder by which we climb from earth to heaven.’ ’’? (See Coward, 1912.) The labor, time and cost of such an investigation as this is amply justified by the results to be expected. A knowledge of the real economic status of a bird means dollars in the pocket of the rancher, for the destruction of any bird which causes serious damage, or the preservation of any bird that is a benefit, has a direct bearing on the size of the crop raised. Nor is the value to the rancher the only value to be considered, for, as will 386 University of California Publications in Zoology \Vou. 11 be seen, a bird has a certain value to society that cannot be reckoned in dollars and cents. Some entomologists, seeing in insecticides the only successful control measure against insects, are inclined to minimize the value of such a natural control as birds. True it is that birds apparently do not prevent or entirely control insect outbreaks. for insects continue to ravage crops, no matter what the bird population. However, if a certain number of insects cause a certain amount of damage, it must follow that a diminution of the number of insects causing damage must cause some dimin- ution of the damage done even if it be not proportional. We are justified in saying, therefore, that the fact that birds destroy ereat numbers of injurious insects shows them to be important agents in contributing to the safety not only of crops, but of all vegetation. Judging from the great numbers of insects destroyed at the time of an insect outbreak, we can safely infer that birds may be instrumental in preventing the appearance of insects in abnormal numbers, by helping to keep the numbers near the normal, which we approximate by the phrase, ‘‘the balance of nature.’ In this practical age almost everything is viewed from the standpoint of dollars and cents. Hence it is desirable that we study the economic value of birds. There is danger, however, in so doing, for such studies may tend to minimize to a certain degree a value which cannot be expressed in dollars and cents. To say that a meadowlark is worth so many dollars to the rancher each year may obscure its esthetic value. The strongest opponents of the theory that birds are bene- ficial often emphasize the esthetic value. The following is a quotation from one of these opponents (Baskett, 1910): ‘‘Make their song, beauty, grace and interesting habits a part of our culture—and their preservation part of our ethics, but do not try to foist them on the farmer as an economic asset, for he knows better in many eases. If the soldier can make better marches under the martial influence of the ‘spirit-stirring drum’ and ‘ear-piercing fife,’ so can the farmer gather inspiration from the activity and cheerfulness of birds.’’ 1914] Bryant: Economic Status of the Western Meadowlark 387 One need only point to the place which birds take in art and literature to prove their esthetic value. The inspiration for some of the finest paintings, poems and other pieces of literature has come from a knowledge of bird life. That exhilaration and inward joy awakened with an acquaintanceship with birds has a real value. What mental pictures stay longer with us than do those gained first hand from nature? Those things which make the world more beautiful make it more fit to live in. Few birds there are that have a greater esthetic value than does the western meadowlark. One reason for this is that it is a conspicuous bird and therefore known to every one. Its song has been pronounced far sweeter than that of its eastern relative. Its plumage and general habits add to its attractiveness. A bird associated with the fields and plains, it adds great interest to the general loneliness and monotony of our great treeless areas. What person traveling along a lonely country road has not been cheered by the bird which stands bobbing on many a fence post and telegraph pole and continually pours forth its “‘Eh heu wheel’iky, wheel’iky, wheel ’iky (For the musical notation of the song of the western meadowlark see Allen, 1881.) The educational value of birds has more utilitarian aspects. 99 Birds teach a code of ethies exceeded only by that of man him- self. The fidelity of parents to each other and to their helpless young and the industry, cleanliness, grace, and cheerfulness exemplified by them add much to the finer ideals of life. The educational and esthetic points of view can even be considered economically. To many, this type of presentation detracts instead of adds. Nevertheless, it is true that the esthetic and educational value of birds has its economic relations. Many a summer resort is chosen because of the abundance of birds in the vicinity, and many a summer vacationist is influenced in his choice of destination by the presence of birds in the vicinity. The value of suburban property is enhanced by the presence of birds. That many a business man has been attracted to certain suburban localities because of the presence of the meadowlark and its song is self-evident. Carrying this point of view to an extreme has often antag- onized certain classes, and herein lies a danger. Yet the facts 388 University of California Publications in Zoology |Vou. 14 here presented can easily be verified. A determination of the status of a bird must include a study of the bird from every point of view. To many city folk the esthetic and educational value of a bird is the more important, for they never see it from any other point of view. Perhaps the rancher is an extremist on one side and the city resident on the other. A modification of the views on both sides is very desirable to a sane appreciation of the value of birds in general and the western meadowlark in particular. The advance made in investigations of the economic relations of birds since Professor Aughey (1878) studied the relation of birds to the locust ravages in Nebraska up to the present, when government experts give the whole of their time to such inquiries, demonstrates the growth of the science of economic ornithology. A study of this advance, however, shows that only a beginning has been made. Although we know in general the food habits of our common birds, yet conditions vary so greatly that we cannot definitely predict the food in any given locality. The work thus far has afforded us a general survey of the food habits of birds and in some few instances has given us definite knowl- edge as to the usual food of certain birds. The thing that eco- nomic ornithology has not afforded us as yet is a detailed study of the food of a particular bird in a given locality throughout the whole year. The importance, then, of a thorough knowledge of the eco- nomie relations of a bird in addition to its life-history is evident. It has been left to one of the new sciences, economic ornithology, to tell us of these economic relations and to explain the real status of birds. The agitation coincident with the establishment of this science had made known at least five facts: 1. Birds are very largely insectivorous, and as a result are important in keeping the numbers of insects in check. 2. The amount of food required by birds is enormous. 3. Birds often considered injurious are really beneficial, and vice versa. 4. Birds change their food habits and feed on the kind ot food most easily obtained. 1914] Bryant: Economic Status of the Western Meadowlark 389 5. Birds are very important in preserving that balance of nature most suited to the interests of man, and their place can- not be filled by any other class of living things. These facts are now familiar. They have furnished a basis for a sane protection, have demonstrated the intricacy of the interactions of organisms, and have helped develop the economic view of birds. Although economic ornithology is fundamentally the study of birds from the standpoint of dollars and cents, and, therefore, includes their use as food, as cage birds, ete., yet emphasis has rightly been placed on the study of the food of birds. As a result, economic ornithology is most often used in a restricted sense and has reference to the study of the food of birds. Great activity is evidenced in this line of work at the present. Not a month passes that there is not some important contribution to economi¢ ornithology, and there is scarcely an entomological re- port that does not mention the value of birds as insect destroyers. To appreciate the work of the present, however, there must needs be some knowledge of the work of the past. A brief historical review of the subject, with emphasis on the methods used, will furnish this needed information. HISTORY OF METHODS IN ECONOMIC ORNITHOLOGY We need only to examine in detail the progress of our sciences to be convinced that there is such a thing as evolution. As we interpret their progress step by step, and thus survey their gen- eral trend, it would seem that the development has been of the orthogenetic type. The biological sciences have been a little slower than others in their development, but they are now taking front rank. One of the most marked tendencies to be noted in history is that of a change from the period when biologists drew conclusions from facts gained from observation only to the present period when more intensive study and experimental evidence are demanded. The period of time previous to 1850 may be termed the prim- itive period, for during this time we find only an occasional mention of the food habits of birds, the entire time of the workers 390 University of California Publications in Zoology [Vou. 11 in this field having been given over to classification and habit notes. The following period (1850-1865) marks the time when the specialized science of economic ornithology was founded. It was a period of interest and agitation. Before the conclusion of this period the modern methods of investigation were introduced into America by Jenks (1860). The period since 1865 is best considered the modern period—a time when the attempt to reach truth is backed by experimental evidence and the work becomes intensive rather than general. (See Loecy, 1908.) To the first period belong such men as Catesby, Edwards, Forster, Latham, Bartram, Hearne, and Barton—men who took an active interest in natural history and enriched ornithological literature with what observational facts they were able to glean. In the latter part of this first epoch there began a marked tend- ency to gain more than superficial facts by observation, and so in the writings of Wilson, Audubon, and Baird we find mention of the food of birds. (See Palmer, 1899.) It was not till 1860 that Jenks (1860) applied scientific method to the study of the food of birds. Previous to this time there had been considerable agitation concerning the value of birds, and many papers dealing with the question appeared in agricultural journals. Le Baron’s ‘‘Observations of the Birds of Illinois Interesting to the Agriculturist’’ is a good type. Other writers at this time were Walford, Holmes, Kirkpatrick, Dodge, Allen, Elliott, and Samuels. The hour was ripe, there- fore, for economic ornithology really to take a place among the sciences as distinct from ornithology itself. The work carried on by Jenks (1860), Treadwell (1859), Aughey (1878), and Forbes (1880, 1882, 1883, 1903) gave the science its real foun- dation, and inaugurated the modern methods now well exemplified and used by the United States Bureau of Biological Survey. At about the same time we find the science getting a start in Europe. Jenks (1860), when introducing the method of stomach examination into the United States, followed Prevost’s (1858) method. M. Florent Prevost was evidently the pioneer in Europe. His paper, ‘‘A Memoir on the Alimentary Regimen of Birds,’’ presented to the Imperial Zoological Society of Paris in the year 1858, and translated by Jenks in 1859, should still 1914] Bryant: Economic Status of the Western Meadowlark 391 be considered a classic. In it he presents an original method of stomach examination and draws some very sane conclusions from the results of thirty years’ work. It is interesting to note that this early worker had a vision of the very method which is advocated at the present time, but which has seldom been followed in detail. He says: ‘‘It ap- peared that it would be of interest to gather, at different periods of the year, the stomachs of all birds which it might be possible to procure, to examine the contents, to note down the exact results of this examination, with the date of the observation, and to preserve these pieces in order to form, in time, a collection by means of which one can in the future verify each of the regis- tered facts.’’ He goes on to point out what he had accomplished in thirty years’ work and the methods which he used in pre- serving stomach contents. These methods were: drying and mounting on cards, drying and preserving in a vial, and pre- serving in aleohol. Tis method of examination appears to have been thorough, for he suggests that an ‘‘attentive examination,’’ in many cases, made ‘‘fragments such as antennae, jaws, lips with their feelers, feet, and often entire heads family, genus, and, in some eases, even the species. Following this is a discussion of the results of the work. The tables used are described thus: ‘‘To this end I have drawn up a uniform table for all the species of birds; each copy of this table concerns a species whose name figures at the head. It represents a series of columns, of which each bears the title of an alimentary regi- men; it is in these columns, and conformably to their title, that I have inscribed both the date of the observation and the indi- cation of the objects found in the stomachs. In fine, each of these tables contains a sufficient number of lines to register observations made during twelve months of the year, and at five different dates in each month.’’ Early workers in America have often failed to consider the food of a bird for the whole year. They have also failed to take into consideration the fact suggested by Prevost in the following words: ‘‘The studies which I have pursued after the method indieated above will establish the fact that the same species of 99 oive the means of determining the 392 University of California Publications in Zoology |Vou. 11 bird changes its food according to the age and season of the year.’’ Also that ‘‘the moment when certain insects inundate a country with individuals without number, . . . coetaneously, this very abundance seems to invite a crowd of different species of animals to feed upon them.’’ It was not till 1882-1885, nearly twenty-five years later, that Forbes clearly poimted out these interrelations between birds and insects. Prevost concludes: ‘‘I am in the course of proving that birds are in general much more useful than injurious to our crops, and that even in respect to the greatest part of the graniv- orous species the evil which is done to us at certain times is largely compensated by the destruction of insects which they accomplish at other times. It is important, then, that we do not destroy these species, but only divert them from the crops when they injure them. Their destruction would permit, with- out counterbalance, the development of many species of insects more fatal still to agriculture. The study of the alimentary regimen has furnished me also some information which I believe useful in comprehending the reunions, the separations, and peri- odieal emigrations which are observed so commonly among birds.”’ (See Prevost, 1858, translation by J. W. P. Jenks.) Since the work of Prevost, economic ornithology has grown rapidly. Germany has probably been most active in the work. Hawks and owls have received the most attention throughout Europe, probably for two reasons. They have been most widely attacked because of their size, and their value is most apparent upon investigation. A number of societies and institutions seat- tered over the continent are actively engaged in studying the economic status of birds. Chief of these are the Kaiserliche Anstalt fiir Land- und Forstwirtshaft zu Berlin, Ornithologische Gesellschaft in Bayern, Paris Museum of Natural History, and the Koniglich Ungarische Ornithologische Centrale. The names of Berlepsch, Rey, Custer, Rérig (1903), and Hollrung (1906) have become well known as workers in this field in Germany. Rorig is the one man who has attempted a computation of the comparative amounts of food by a weight method. Csiki (1909) and Greschik (1910, 1911) have been the principal workers in Hungary. Their researches have been mainly confined to the birds of prey. 1914] Bryant: Economic Status of the Western Meadowlark 393 A committee appointed by the British Association for the Advancement of Science is now investigating the feeding habits of British birds by a study of the contents of the crops and gizzards of both adults and nestlings, and by collation of obser- vational evidence, with the object of obtaining precise knowledge of the economie status of many of the commoner birds affecting rural seience. Data as to the environmental conditions under which the bird was feeding and the available food supply are obtained with each specimen. All data obtained from the stomach examination are tabulated, and the weight of the bird and the condition and weight of the gizzard contents are recorded. The United States Department of Agriculture has carried on the most extensive work in economic ornithology ever attempted by one institution. Study along this line was begun in 1885. Since that time over sixty thousand stomachs of birds have been examined, and the results, with the addition of data collected in the field, have been published in more than one hundred and thirty bulletins. Other investigations have also been conducted. The most extensive work has been done in Illinois by the pioneer economic ornithologist, Professor S. A. Forbes. Massachusetts, Wisconsin, and Pennsylvania have also carried on investigations, the work being done by Forbush (1908), King (1883), and Warren (1888) respectively. Practically every state has been supplied with some literature on the subject by the state university or the agricultural experiment station. At the third ornithological congress at Paris in 1900, the section of economic ornithology and bird preservation reported in favor of urging all countries and even their governments to take up seriously the subject of the utility or harmfulness of birds as being of the greatest economic importance. It was urged that ‘‘inquiries should be instituted on regular business lines, that migratory and non-migratory species alike should be observed during every month of the year and for several years in succession, that the contents of their stomachs should be care- fully noted, and lists prepared of their action towards the farmer’s crops.” The amount of careful work along these lines which has been done since this time is very encouraging. The last few years 394 University of California Publications in Zoology (Vou. 11 have seen a number of the leading magazines take up the subject of the economic value of bird life, and with illustrated articles they have brought to the attention of many the value of birds to the farmer. Largely because of their depredations, the demand for an intimate knowledge of the food of birds has become very pressing, and yet it is interesting to note that attention to the economic side of ornithology was not aroused by the depredations of birds, but by the depredations of insects. A comparison of the methods used up to the present will clearly show the progress which has been made in the science of economic ornithology. Such a comparison is afforded by the following sequence of methods used in determining the economic value of birds: Sequence of methods used in determining the economic value of birds: 1. Observational notes on the food of birds. (Wilson, 1808- 1814; Audubon, 1827-1838.) 2. Critical observational study of the food of birds. (Le Baron, 1855; Holmes, 1857; Weed, 1903.) 3. Examination of the stomach contents of birds. (Jenks, (King, 1883.) 4. Experimental feeding of captive birds. (Treadwell, 1859.) 5. Observation plus stomach examination. (Aughey, 1878; Judd, 1902.) 6. Observation plus stomach examination plus experimenta- tion. (Forbes, 1903; U. S. Biological Survey. ) Similar progress can be noted in the methods used in de- termining the food of birds. Their sequence has been as follows: 1. Investigation of food with no reference to time or locality. (King, 1883.) 2. Investigation of food at time and locality of depredations. (Forbes, 1903; Wilcox, 1892; Aughey, 1878; Bryant, 1911, 1912d.) 3. Investigation of food according to the month, regardless of exact locality. (Jenks, 1860; Beal, 1907, 1910.) 1914] Bryant: Economic Status of the Western Meadowlark 395 4. Investigation of food according to the month in the same locality. (Forbes, 1903; Bryant, 1912a.) 5. Investigation of food according to the month in the same locality, with a comparison with many different localities. (See p. 454.) The determination of the economic status of birds has like- wise progressed. The sequence of the criteria used has been as follows: 1. Inferential evidence. 2. Cireumstantial evidence. 3. Number of injurious insects eaten. 4. Proportion of percentage volume of injurious, neutral, and beneficial insects and seeds destroyed. 5. Contrast of all harm vs. all good, including knowledge as to life-history. From these comparisons it can be seen that great progress has been made. To infer that a bird is injurious simply because it is seen in a grain field or orchard, or to brand it as injurious because of circumstantial evidence in the form of grain or fruit found in the stomach, are obsolete methods today. Furthermore, we recognize at the present time that a bird may eat some bene- ficial insects and still be a valuable bird. Nothing less than a knowledge of the food for the whole year, combined with a knowledge of the life-history of the bird concerned, allowing a balanee of all the benefits conferred with all the damage done, meets the requirements of the present. INVESTIGATION OF THE ECONOMIC STATUS OF THE WESTERN MEADOWLARK IN CALIFORNIA Interest centered around the meadowlark for some time pre- vious to the institution of an investigation. A rather dormant complaint against the depredations of the meadowlark in sprout- ing grain fields was brought to a head in a bill (no. 229) intro- duced by Assemblyman Stuckenbruck of San Joaquin County 396 University of California Publications in Zoology (Vou. 11 into the State Legislature on January 11, 1909. The bill, which proposed to amend section 637 of the penal code of California, passed through the committee, but was refused passage, the vote standing 32 to 28. On the motion to reconsider, the bill was again brought to a vote and passed with a vote of 41 to 28. The Committee on Fish and Game of the Senate reported favorably on the bill, but it was refused passage on a vote of 17 to 12. In 1911 Assemblyman Stuckenbruck, at the request of his constituents, introduced a similar bill with the proviso that in the counties of Tehama, Butte, Sutter, Sacramento, Yolo, Colusa, Glenn, San Joaquin, Stanislaus, Tulare, and Kings the meadow- lark be not included among the birds protected by the act, hoping thus to allay the opposition met from other parts of the state at the former session of the legislature. This bill, being referred to the Committee on Fish and Game, was returned to the Assem- bly with a majority report in favor of its passage and a minority against its passage. It failed of passage on March 20. Continued complaints from the farmers and fruit growers of the state have been made to the State Fish and Game Com- mission regarding the losses to crops caused by the depredations of birds. The commission has been repeatedly urged to take strong measures to avert the damage done. The usual measure urged is that the particular bird in question should be placed on the unprotected list. On the other hand, many scientists and others interested in birds have pointed out the fact that birds confer a great benefit in keeping down the number of injurious insects and weed seeds, and thus they fill a niche in the economy of nature most suited to mankind which is not and ean not be filled by any other form of life. Experience has shown that many belonging to the first class have based their complaints on circumstantial or partial evidence or on evidence not sufficiently reasoned out. Furthermore, these complaints have brought out the fact that really very little is known of the food habits of birds of California. Certain it is that a knowledge of the food habits of a bird is necessary to a determination of its economic status. As a result, therefore, the commission thought it wise that legislation should be based on scientific investigation as to the value of birds, and not on circumstantial evidence. Conse- 1914] Bryant: Economic Status of the Western Meadowlark 397 quently an investigation into the relations of the birds of the state to agricultural and other interests was instituted. The institution of the investigation was largely due to the interest and energy of Mr. John P. Babeock, Chief Deputy of the California State Fish and Game Commission, 1910-11, and Professor Charles A. Kofoid of the Department of Zoology of the University of California. A COMPARISON OF METHODS IN ECONOMIC ORNITHOLOGY The attempt to show the amount of the different kinds of food contained in the stomachs of birds has led to the use of two distinct methods, both of which must be considered valuable, and both of which approximate the end sought. A method introduced by King (1883), and later used by Newstead (1908), gives the total number of birds taking the different kinds of food compared with the total number of stomachs examined. The second method, employed by the United States Biological Survey, depends entirely upon the comparative volume of the different kinds of food found in the stomach, calculated in per cent of total volume and averaged. Ce i ea ene We ae P he et 6 6 6 0€ Aouod “Wh “V Ayano, nodrysig ‘wosstg 8 ‘OUT M “Sf ‘Surppey ‘wos1apuy re Viggo ae eee eo eee ae a 1G aes ee L LE ol 69 souleg *) “Wd Ayunoy yppoqun yy = “WBYBIY) “OM “eyorugy = se ops ae E me 3 Pay = 4 S iy mB a) By 4 TOPT[OD Aqreoory r 2 Be ‘J 2 2, Be Om So me _ ES w ey = rl , BF B gas QA oe Py 3 = z 5 Bo Bo a ay a < 5 vu — ,—— — ay uaye} S1aqum yy NOILVNINVX® HOVWOLG YOd ATAVLIING TVIYALVIY DNIMOHY ATAV I —'T 416 417 Economic Status of the Western Meadowlark 1914] Bryant 88 G OL 16 F OT 681 OLT 6L FES O3LT | Canin ae VR wes MS Ad SOS er Ca a cae es Mae Gro) Ge ae Me oe ee nee LS i setia ea tp OL | lig ap kad see oo ei es AS ds Beran, Be tom. Z Lg $l (EL pate) genes 9 ae Se ae cP 6 lt 66 Cie sie a es eae is 69 Te aes G 8& es are Ae 08 ae, SOW eee Meet me een van igs a ge ¢ SI ean ives Z Se eat a ae LT Se ee, 9 Oe ee ae ee eee oe 5 | Eee Rate er, See tia mere i OL G G ZL 6 FE Chae ae RN Dateien hese 18 gi ree Mapes oe eee eae G OL UP iawee Rae tam Gerace) tn Ck be abe, 9 Baa FL OT ay) ee Roe eek ee oe ete ae Scien as, G L L GS Oe eae ne ce) Aten ies as 88 €L Z 0& OF e hae pe Ahn Ue ee Oars pee ee ee eee EY Oe ae eee a H i Loa! Lon onl lon) loa! lanl Lava) onl load pene ieee Be bee ne Pee MURR ea. (cme Zee GR a ge ge Se Se me, e 2 oz] Ey 5 Ps i EB 5 25 aR OG 3 é a (aa a a ——— —— J uayRy S1aquin Nn papnjaUuog—NOILYNINVX( HOVWOLG YOK AIAVLING IVIAALVIY ONIMOHY WAV L—'T paj}uasar -daa syjuom jo 1aquinN jo 1aquiny syiv[Moprour s[B10 J, quedig ‘0 "H dojxeq “HY SUIOT, (QO WoOsurqoy “SM Tasky “Hf “‘ysinqso A “HO aA “VL uBMryNy “of y00GLL “(OV 1240 "H “HL say “¢ H YOous vf Arua HW “VO AaT[VUY “M “OL SIG “N ‘I'S Allog “Hf 10}0a][0D SnoOdUe[[AOSTIAL Ayunoy petoeduy Vead uy AyuNODH oserq weg ‘osorq weg APUNOD asuvig, ‘O10, [A AJUNOD IPISI9ATYY ‘OpISIOA TY AYUNO: OUTpLeUIEg URG ‘oulpivuleg UeBg Ayanoy Bainjuad A ‘gainjue A Ayano ule sp ‘ppeysiaxeg Ayunoy oAuy ‘oud Sig AyunoH Breqieg BURG ‘BlLIB BURY Ayunoy Aatoz, WOW ‘SRBUILTRQ AyunoyH oylueag weg “TO 4ST[LOH AyuUNO|D ssuryp ‘piLozue yy Ayuno,) ousedy ‘oused Ayunoy viopeyy ‘B10 PRI Aqu[woory 418 University of California Publications in Zoology (Vou. 11 Sixtoten monthly collections Complete series for one year Complete series tor two years Fig. A.—Map of California showing localities in which collections of western meadowlarks have been made for the purpose of stomach exami- nation. A complete series is a minimum of six birds collected each month in a year. Table I, pages 416-417, gives a summary of the material available. EXAMINATION OF STOMACH CONTENTS On removing the stomach (gizzard) and tag from the cloth, the stomach was carefully cut open, the incision being made with a scissors along the longest axis and through the muscles, starting at the cardiae opening, and the contents emptied upon a glass 1914] Bryant: Economic Status of the Western Meadowlark 419 plate. Great care was taken to see that every bit of the contents was scraped from the walls of the stomach. A Zeiss binocular was used in examining and determining the material found. Where possible, counts were made of all vegetable and animal elements of food. The amount of mineral matter used as grinding material was computed by a calculation in per cent of the com- parative volume. The comparative volume of each kind of food was calculated in per cent of total volume contained in the stomach examined. In the estimation of apparent volume there is always a personal error. However, since this method is depended upon to furnish evidence as to the comparative amounts and not actual amounts, the personal error is largely distributed in the averages. Parts of insects and weed seeds used in identification were wrapped separately in small pieces of paper to prevent their mixing with the rest of the stomach contents. Where possible, the heads of insects were used as a safe cri- terion of the number eaten. In many cases dependence was necessarily placed on an enumeration of the mandibles. In the ease of grasshoppers the mandibles are probably retained in the stomach longer than the soft parts, but experiment has shown that the stomach is completely emptied in four hours, so that it is necessary only to give a long enough period of digestion to make such an enumeration dependable. The fact that the mandibles of grasshoppers may be found along the entire length of the digestive tract also supports the view that this criterion is trustworthy. Beetles, bugs, bees, and ants were readily counted, because the heads and thoraces of these insects remain long undigested. Partly digested grain and weed seeds were computed in per- centage volume, but in addition the undigested kernels and seeds were counted. Owing to the finely comminuted condition of the food to be found in the intestines, that found in the stomach alone was used as evidence of the food taken. The stomach alone gives the best unit of volume. The consideration of the food to be found in the intestines could at best but show evidence as to food for a longer time previous to the death of the bird. 420 University of California Publications in Zoology (Vou. 11 In all cases the stomach contents were preserved in vials, so that verification of the results will be possible at any time. As a rule, the contents have been preserved by drying, but where certain animal matter such as larvae was present the material has been preserved in seventy per cent alcohol. After each examination the kind and quantity of food was recorded on a stomach blank. Complete data were recorded on larger blanks. Summaries giving the results of the examinations of the different collections were made in the form of tables. IDENTIFICATION OF STOMACH CONTENTS Collections of insects and seeds for comparison were most helpful in identifying the different insects and seeds. Insects and seeds, if in good condition, can be determined at least to the genus by this method. Floating out the wings of certain insects in water and the mounting of other parts in some clearing fluid are methods which have had to be resorted to occasionally. In the examination of a large series of stomachs it is nearly always possible to obtain a fairly good specimen of an insect which is commonly taken as food, for some bird is usually found which has taken such an insect just before being killed. Foop or THE WESTERN MEADOWLARK IN CALIFORNIA The food of the western meadowlark is made up of both vegetable and animal matter. The vegetable food is largely com- posed of grain and seeds. The animal food is made up largely of insects. The accompanying diagram (fig. B) shows the rela- tive amounts of the different kinds of food taken during the year. A discussion of each kind of food is followed by a statement of the ‘‘amount destroyed’’ and the ‘‘economic importance.’’ VEGETABLE Foop Grain Grain forms the largest percentage (seventy-five per cent) of the vegetable food for the year and makes up thirty and eight- tenths per cent of the total food for the year. But a small part (one per cent) of that found in the stomachs has been sprouted. 1914] Bryant: Economic Status of the Western Meadowlark 421 This was therefore in all probability pulled from the seeded fields. Oats is the grain most often taken. It is not only preferred, but is the most available. Much (about seventy per cent) of that found in the stomachs is wild oats (Avena fatua). This oat is so mixed with the tame varieties that part of it must be consid- ered a loss to the rancher, for it makes good feed. Nearly half PROPORTIONS OF DIFFERENT KINDS OF FOOD FOR THE YEAR 63.3% ANIMAL FOOD ee 36.7% VEGETABLE FOOD Fig. B.—Diagram showing relative amounts of different kinds of food taken during the year by western meadowlarks. 422 University of California Publications in Zoology (Vou. 11 of all the grain taken by the birds examined was consumed during the three winter months—November, December, and January. It is apparent, therefore, that availability, lack of insect food, and possibly the sprouting condition of the grain are responsible for this. Owing probably to the feeding habits of the bird, mixtures of different grains are seldom found. The stomachs usually contained one kind of grain only. Barley, because of its greater availability, is more often taken than wheat. The barbs are seldom found in the stomach. One hundred and fifty-five out of one thousand and nine hundred birds had eaten barley. Wheat is taken less often, probably beeause it is less available. One would suppose that a grain without the hull would be the more palatable. Field corn (Zea mays) was taken by only seven birds out of one thousand nine hundred and twenty, while ten had eaten white milo maize (Andropogon sorghum) and other varieties of Egyptian corn. Quantity destroyed—During the months of December and January the meadowlark feeds largely on grain. Grain forms nearly thirty-one per cent of the food for the year. Stomachs are often found entirely filled with oats, barley, or wheat. As many as thirty kernels, with enough hulls to account for as many more, have been found in a single stomach (pl. 22, fig. 3). Less than one per cent of the grain found in the stomachs has been sprouted grain. Practically no grain is found in the stomachs during the months of March and July. Im that grain is more slowly digested than insects, a smaller volume of grain is prob- ably consumed daily. Economic importance.—For its destruction of sprouting grain, the western meadowlark justly deserves criticism. In small fields, where the birds are numerous, losses are great. The facts which tend to minimize the damage done are as follows: Much of the grain found in the stomachs is wild oats. Since cultivated oats always contains more or less wild oats in California, it can- not be said that injury does not result from the destruction of the latter. However, much of that eaten must be taken in places where no injury results. All of the grain taken in the months of August, September, and October must be considered 1914] Bryant: Economic Status of the Western Meadowlark 423 waste grain and of little economic importance. Meadowlarks are not known to attack heads of grain. Whatever field grain is taken is picked up from the ground. Damage done to sprouting erain can result only during a limited period of time (two weeks). After the second leaf appears no damage can result. Weed Seed Weed seed evidently forms the principal part of the vegetable diet of this bird where or when grain is not available. The seeds of such weed pests as tarweed, mustard, tumbleweed, Napa thistle, pigweed, amaranth, canary grass, Johnson grass, foxtail, and sunflower are consumed in large quantities. The seeds of such forage plants as the burr-clover and filaree are commonly eaten. The seeds of filaree (Hrodium cicutarium) form the largest per- centage of the weed seeds taken as food. A stomach has seldom been found completely filled with weed seed, for some sort of grain, especially wild oats, is nearly always available with the weed seeds. Nevertheless during the late fall weed seeds make up a considerable part (twenty per cent) of the diet. Grass has been occasionally found in the stomachs. Whether or not it was taken intentionally it is impossible to state. Small sprouts from sprouting grain and sprouting seeds have been found in some instances. As a rule the seeds appear to be sep- arated from the large sprouts when eaten. Small pieces of straw and other vegetable fiber found in the stomachs can be classified as rubbish picked up with the food. There has been a slight complaint that meadowlarks damage sugar beets by feeding on the sprouting seeds. Mr. F. J. McCoy, assistant manager of the Union Sugar Company, Betteravia, California, says on this point: ‘‘I have noticed meadowlarks in early spring in our beet fields, but noticed they were feeding ? on insects.’’ Stomach examination has failed to disclose any beet seeds. The stomachs of birds collected in beet fields have been found filled with insects. Quantity destroyed—The maximum consumption of weed seed occurs in October, when nearly one-fourth of the food is made up of this kind of food. Weed seed amounts to five and 424 University of California Publications in Zoology (Vou. 11 three-tenths per cent of the food for the year. Over 150 seeds of filaree (Hrodium sp.) have been taken from a single stomach. Tarweed, pigweed, tumbleweed, mustard, turkey mullein, Napa thistle, Johnson grass, canary grass, foxtail, sunflower, burr- clover, and nightshade seeds have been found in numbers ranging up to fifty. In some few instances stomachs have been found entirely filled with weed seeds. Western meadowlarks appear to feed upon weed seeds to a considerable extent during the time in which they are available. Most weed seeds do not mature until late summer and fall. After plowing begins they are no longer available in cultivated districts, except along fence rows and in uncultivated fields. Economic importance.—The destruction of weed seeds must be considered of value to the agriculturist. Weeds even in small numbers take a toll in the grain field. The destruction of weed seeds accomplished by western meadowlarks must help to limit, in some measure, the number of weeds which grow in fields and fence rows the following year. Meadowlarks feeding in grain fields must destroy weed seed that would not otherwise be de- stroyed. Their habit of feeding on sprouting seeds increases their efficiency as weed-seed destroyers. Seeds eaten are digested. In no ease have undigested seeds been found in excrement. Fruit No vegetable matter found in the stomachs has been identified as fruit. Grape seeds have been found in a number of cases and there is no doubt that western meadowlarks eat grapes to a slight extent. No serious complaint as to their depredations in this direction has been received. The stomachs of practically all of the birds collected in vineyards have been filled with insects, mostly beetles. A systematic list of the grain and weed seeds found in the stomachs follows: Grain Oats Barley Wheat Field corn (Zea mays) Sorghum (Andropogon sorghum subsp.) 1914] Bryant: Economic Status of the Western Meadowlark 425 Fruit Grape seeds (Vitis sp.) Weed seed Gramineae (Grass family) Andropogon sorghum halepensis. Johnson grass Panicum sp. Panie grass Chaetochloa glauca. Bristly foxtail Chaetochloa viridis. Foxtail Phalaris minor. Small canary grass Avena fatua. Wild oats Bromus sp. Brome grass Lolium temulentum. Darnel Hordeum sp. Barley grass Cyperaceae (Sedge family) Carex sp. Sedge Polygonaceae (Buckwheat family) Rumex sp. Dock Polygonum sp. Knotweed Chenopodiaceae (Goosefoot family) Chenopodium sp. Goosefoot pigweed Amarantaceae (Amaranth family) Amaranthus graecizans. Tumbleweed Amaranthus sp. Amaranth Portulacaceae (Purslane family) Lewisia sp. Bitter root Ranunculaceae (Buttercup family) Ranunculus sp. Buttercup Cruciferae (Mustard family) Brassica nigra. Black mustard Brassica sp. Mustard Leguminosae (Pea family) Medicago hispida. Burr clover Medicago arabiea. Spotted medick Melilotus indica. Yellow melilot Melilotus sp. Sweet clover Trifolium sp. Clover Lupinus sp. Lupine Geraniaceae (Geranium family) Erodium cicutarium. Red-stem filaree Erodium sp. Filaree Euphorbiaceae (Spurge family) Eremocarpus setigerus. Turkey mullein Malvaceae (Mallow family) Sida hederacea. Alkali mallow Onagraceae (Evening Primrose family) Oenothera ovata. Golden eggs Primulaceae (Primrose family) Anagallis arvensis. Pimpernel 426 University of California Publications in Zoology (Vou. 11 Boraginaceae (Borage family) Amsinckia intermedia. Amsinckia Amsinckia sp. Amsinckia Cynoglossum sp. Hound’s tongue Rubiaceae (Madder family) Galium sp. Bedstraw Solanaceae (Nightshade family) Solanum sp. Nightshade Compositae (Sunflower family) Lactuea seariola. Prickly lettuce Centaurea melitensis. Napa thistle Centaurea solstitialis. Barnaby’s thistle Carduus sp. Thistle Hemizonia sp. Tarweed Helianthus annuus. Common sunflower Iva axillaris. Ragweed Economic importance of vegetable food.—The destruction of sprouting grain means a loss of dollars and cents to the rancher. This loss is minimized somewhat by the limited time during which injury is possible and the possibility of protective measures. A much smaller loss can be attributed to the destruction of grain picked up in newly sown fields. Grain on or near the surface of the ground in seeded fields is of doubtful value, as it cannot be depended upon to furnish a strong, healthy plant. Much of the wild oats and some of the tame oats must be considered waste grain or uncultivated grain. Its destruction, in spite of its utility as feed, cannot be considered a direct loss in money value. Practically all the other seeds destroyed are the seeds of weed pests. The destruction of the seeds of certain forage plants such as filaree could be considered a detriment if they were destroyed in large enough quantities to make any difference in the amount of forage available. This same plant is considered a weed in many places. Any destruction of the seeds of thistles, sunflowers, Johnson grass and like weeds must be considered a benefit. ANIMAL Foop Coleoptera (Beetles) The most constant article of diet of the meadowlark consists of beetles. The habitat of the bird would foreeast this fact. Ground-beetles (Carabidae, Tenebrionidae), click-beetles (Elate- 1914] Bryant: Economic Status of the Western Meadowlark 427 ridae), and weevils (Rhynchitidae, Calandridae, Otiorhynchidae ) form the largest per cent of this kind of food. Representatives of practically every family of the Coleoptera, however, have been found in the stomachs. A systematic list of the beetles identified follows: Cincindelidae Cineindela sp. Carabidae Calosoma sp. Amara californica Dej. Amara conflata Lee. Calathus ruficollis Dej. Platinus bicolor Lee. (?) Staphylinidae Staphylinus tarsalis Mann. Creophilus villosus Silphidae Silpha ramosa Say Dermestidae Dermestes sp. Erotylidae Languria sp. Histeridae Saprinus fimbriatus Lee. Buprestidae Elateridae Cardiophorus tenebrosus Lec. Anchastus cinereipennis Mann. Drasterius livans Lee. Drasterius sp. Megapenthes aterrimus Horn Dolopius lateralis Melanotus variolatus Lee. Limonius infuseatus Mots. Limonius canus Lee. Limonius ealifornicus Mann. Lampyridae Telephorus consors Lee. Malachidae Collops marginellus Lee. Scarabaeidae Aphodius subaeneus Lee. Aphodius granarius Linn. Aphodius rugifrons Horn. Hoplia sp. Cotalpa ursina Horn Ligyrus gibbosus De Greer Harpalus pennsylvanicus Dej. Agonostoreus maculatus Lee. Pterostichus sp. Bladycellus rupestris Say Anisodactylus dilatatus Dej. Anisodactylus sp. Dytiscidae Agabus lugens Lee. Chrysomelidae Glyptoseelis albidus Lee. (?) Gastroidea sp. Diabrotica soror Lee. Disonycha sp. Chaetocnema sp. Microrhopala melsheimeri Cr. Tenebrionidae Blapstinus gregalus Casey Blapstinus rufipes Casey Blapstinus elongatus Casey Coniontis subpubescens Lee. Coniontis viatiea Esch. Eulabis pubescens Lee. Eurymetopon sp. Eleodes sp. Meloidae Otiorhynchidae knigopsis effracta Lee. Rhigopsis sp. —__— (1) Curculionidae Sitones californicus Fah. Sitones sordidus Lec. Lixus perferatus Lee. Cleonus virgatus Lee. Centrocleonus near angularis Lee. Baris cuneipennis Casey Baris sp. Calandridae Sphenophorus vomerinus Lee. Sphenophorus simplex Lee. Sphenophorus sp. 428 University of California Publications in Zoology (Vou. 11 Quantity destroyed.—Beetles are taken every month of the year, and form 21.3 per cent of the total food. Stomachs have often been found filled with nothing but beetles. From twenty to fifty have been found in a single stomach. Wireworms, the larvae of click-beetles (Elateridae), are taken in large numbers where they are available. As they are less often seen above ground than ecutworms, it is only natural that they do not form nearly so large a percentage of the food for the year. The adult click-beetles are also taken (see pl. 24, fig. 8). Economic importance.—Wireworms are injurious to the roots of plants. Damage by them to garden truck and pasture land is of common occurrence. The ability of the meadowlark to probe into and remove from the soil such insects increases its value as an insect destroyer. The destruction of wireworms must be considered a benefit of considerable importance, especially in meadow and pasture land. By far the greater number of beetles taken as food are the common ground beetles (Carabidae). These beetles are often classified as beneficial insects, because they are supposed to feed on other injurious insects. Certain ones are predacious and are known to feed on fly and beetle larvae in California. Of the food habits of others little is definitely known, and we are justified in speaking of them as neutral, for they do practically no harm and are not known to do any particular good. Tiger-beetles (Cineindelidae) and earrion-beetles (Staphylinidae), eaten to some extent, must be numbered among the beneficial beetles de- stroyed. The meadowlark, however, does feed upon many injur- ious beetles, chief of which are click-beetles (Elateridae), pina- cate beetles (Eleodes sp.), leaf-beetles (Chrysomelidae), snont- beetles (Otiorhynchidae, Curculionidae), and weevils (Calan- dridae). Among the leaf-beetles is numbered the destructive California flower-beetle (Diabrotica soror). This and other members of the family constitute some of the worst beetle enemies of our crops. Snout-beetles (cureulios) and weevils (Spheno- phorus sp.) are well-known pests of fruit and grain. The con- tinual destruction of large numbers of these injurious beetles must be considered a decided benefit. 1914] Bryant: Economic Status of the Western Meadowlark 429 Orthoptera (Grasshoppers and Crickets) Grasshoppers and crickets form a large percentage of the meadowlark’s food during the summer and fall, making up as high as eighty-five per cent of the food in August. The species of grasshopper taken is the one most available. Practically all of the species found in the state are doubtless represented in the stomachs. The common ericket (G@Gryllus) and the Jerusalem ericket (Stenopelmatus sp.) are common articles of diet. Katy- dids (Loeustidae), being less common insects and having a different habitat, are not taken so often. A systematic list of the Orthoptera found in the stomachs follows : Gryllidae Arphia sp. Gryllus integer Seud. Dissosteira spureata Saus. Gryllus pennsylvanicus Burm. Conozoa behrensi Saus. Locustidae Aeridiinae (?) Maerocentrum sp. Oedaleonotus enigma Seud. Conocephalus acutalus Seud. Melanoplus devastator Seud. Stenopelmatus irregularis Brun. Melanoplus differentialis Uhler Stenopelmatus sp. (?) Melanoplus uniformis Seud. Aecridiidae Fulgoridae Cedipodinae (?) Labia minor Camnula pellucida Seud. Quantity destroyed—Next to beetles, grasshoppers form the most important article of diet. Nearly fifteen per cent of the food for the year is made up of these insects. Parts of as many as twenty-six large grasshoppers (one inch or over in length) and fifty-eight small grasshoppers (one-half inch in length) have been found in a single stomach. The maximum amount of this food is taken in June, July, and August, the birds feeding almost exclusively on these insects during these months. The state over, some grasshoppers are taken by the meadowlarks every month in the year. The quantity taken closely parallels the abundance of these insects. Crickets as well as grasshoppers are relished by the meadow- lark. As many as fifteen pairs of mandibles have been taken from a single stomach, showing that at least fifteen common black 430 University of California Publications in Zoology |Vou.11 erickets (Gryllus pennsylvanicus) had been eaten within four hours by that particular bird. Five per cent of the food for the year is made up of crickets. Wood crickets, better known as Jerusalem crickets (Stenopelmatus sp.), being less abundant than the common cricket, are less often taken as food. Economic importance-—Grasshoppers can be classed as injur- ious insects. The extent of their damage can be traced to their abundance rather than to the presence of any particular kind of grasshopper. The species which most often become abundant enough to cause serious losses in this state are the differential grasshopper (Melanoplus differentialis), the pale-winged grass- hopper (Melanoplus uniformis), the devastating grasshopper (Melanoplus devastator), and the valley grasshopper (Oedaleo- notus enigma). All of these grasshoppers are destroyed in great numbers by the meadowlark. The more abundant these insects become, the more do these birds turn their attention to this kind of food. Where grasshoppers are abundant, meadowlarks have been found to average as high as fifty grasshoppers a day. (See ‘Bryant, 1912d.) As a grasshopper destroyer, the meadowlark is unequaled by any other bird unless it be the blackbird, and then only because of greater numbers of blackbirds. As grasshopper outbreaks continue to ravage certain parts of the state each year, the meadowlark performs a service to agriculture that can hardly be overestimated, in that it helps to keep the insects down to normal numbers, so that losses do not result, and prevents greater losses by taking a greater toll at the time of an outbreak. Crickets are usually classed as injurious insects. The degree of injury, as with the grasshoppers, depends largely upon their abundance. Since the species of crickets fed upon by the mead- owlark feed almost entirely upon plants and are often destructive to grain, their destruction is to be desired by the rancher. This is especially the case with the Jerusalem cricket, which is very destructive to potatoes. Lepidoptera (Butterflies and Moths) The general law that birds do not eat butterflies to any great extent appears to hold good in the case of the western meadow- lark. (See p. 481). However, the following dependable obser- 1914] Bryant: Economic Status of the Western Meadowlark 431 vation made by Mr. John G. Tyler of Fresno, California, also furnishes evidence of the fact that butterflies are occasionally, at least, destroyed. ‘‘ While strolling along the road east of this city the writer noticed a field of alfalfa that was infested with yellow butterflies. A nearer approach revealed the presence of several meadowlarks, and I was so fortunate as to see one of these birds seize a butterfly and make way with it. I am not prepared to say that the victim was actually swallowed, but it was certainly captured and killed.”’ The larvae of butterflies and moths are common articles of diet. Cutworms and caterpillars form ten per cent of the food for the year, reaching a maximum in May and June, when they amount to nearly a third of the meadowlark’s food. Even hairy caterpillars do not escape destruction. In one instance the larva of the mourning-cloak butterfly (Huvanessa antiopa) has been found in the stomach. Smaller hairy cater- pillars are of common occurrence. Both the larva and pupa of the sphinx moth have been taken from stomachs. Pupae do not form so important a part of the diet as do the larvae. The only Lepidoptera positively identified follow: LEPIDOPTERA (BUTTERFLIES AND MorTHs) Noctuidae Nymphalidae Peridromia sp. Eugonia californica (Boisd.) (?) Euvanessa antiopa (Linn.) (?) “(?) Papilio sp. Sphingidae (?) Phlegethontius sp. Quantity destroyed—Cutworms and caterpillars form about twelve per cent of the food for the year. The maximum quantity is taken in the months of March and April, when almost half of the food taken is made up of these insects. Many of the stomachs contained as many as twenty large cutworms or caterpillars. One bird collected at Red Bluff, Tehama County, contained sixty- six cutworms and over thirty small beetles (pl. 23, fig. 5). 432 University of California Publications in Zoology [Vou. 11 Economic importance—Cutworms and army worms can be classed as two very important pests in California. Garden truck and even trees are sometimes defoliated when these insects hecome numerous. The depredations of the grape ecutworm are only too well known in the state. Caterpillars are vegetable feeders and are always classed as injurious. The destruction of these pests in very large quantities by the western meadowlark must cause a direct saving to the rancher and fruit grower. Hemiptera (Bugs) Stink-bugs (Pentatomidae) appear to be relished in spite of their excretions, for they are taken in large numbers. Squash- bugs (Anasa sp.) have been found in only a few instances. Negro-bugs (Corimelaena) form the only other important Hem- iptera taken. Cicadas appear to be relished and often caught. Two stomachs have contained aphids (Aphis brassicae). The following Hemiptera have been identified : HEMIPTERA (Bucs) Jassidae Coreidae ——_——? Corizus sp. Aphidae Alydus pliosulus Aphis brassicae Linn, Anasa sp. Membracidae Pentatomidae Stictocephala franciscana Stal. Podisus pallens Stal. Cicadidae Podisus sp. Platypedia areolata Uhl. Euschistus conspersus Uhl. Platypedia minor Uhl. Euschistus servus Say Reduviidae Corimelaenidae SS ? Corimelaena sp. Quantity destroyed—The commonest true bugs destroyed by western meadowlarks are stink-bugs (Pentatomidae), negro-bugs (Cormelaenidae), leafhoppers (Jassidae), and cicada flies (Cica- didae). They form nearly two per cent of the food for the year. As many as twenty stink-bugs have been taken from a single 1914] Bryant: Economic Status of the Western Meadowlark 433 stomach. Negro-bugs are not taken in such laree numbers, nor are they so abundant. Two stomachs have been found almost filled with leafhoppers, and many others contained two to ten of these insects. Cicadas, near relatives of the eastern seventeen- year locust, are occasionally taken, probably as often as they are available. Bugs form over three per cent of the food for the year. Economic importance. Most stink-bues are vegetable feeders and occasionally give trouble. Negro-bugs are troublesome on berries. In the destruction of these insects the western meadow- lark is also conferring a benefit. Leafhoppers are injurious to plants, because they secure their food by sucking the juice of the plant. Any destruction of leafhoppers, however small, is of value. The cicada in California is not abundant enough to be of economic importance. It lays its eggs in the sapwood of plants and trees. Since these insects, if they became abundant, would cause trouble as does the seventeen-year locust of the east, their destruction is to be looked upon with favor. Hymenoptera (Ants, Bees, and Wasps) Ants appear to be taken irrespective of size or kind, for they are to be found from the smallest to the largest. The common red and black ants (Messor, Pogonomyrmex), field ants (Formica), and carpenter ants (Camponotus) are most abundant in the stomachs. Ichneumon flies are taken in considerable numbers. Bees and wasps form a less percentage of the food made up of Hymeno- ptera. In but one or two cases was a bee definitely identified as a honey bee (Apis mellifera). Solitary bees (Chrysis) and even bumblebees (Bombus californicus) have been found. Cow- killers (Mutillidae) are occasionally eaten, although it has com- monly been supposed that they were well protected from attack by their sting, hairy covering, and warning coloration. For several reasons the Hymenoptera have been very difficult to identify. The finely comminuted condition of the insects has proved an almost insurmountable difficulty. The following only have been identified : 434 University of California Publications in Zoology |Vou.11 HYMENOPTERA (ANTS, BEES, AND WASPS) Ichneumonidae Vespidae 2 Polistes aurifer Sauss. ? Polistes minor Beauv. — ? Sphegidae ——__———_ ? Ammophila sp. Mutillidae Formicidae Sphaerothalma californica Formacinae Sphaerothalma aureola Camponotus sp. Apidae Formica sp. (?) Apis mellifera Dolichoderinae Bombidae Tapinoma sessile Say Bombus ealifornicus Smith Myrmicinae Chrysididae Messor andrei Mayr. Chrysis sp. Pogonomyrmex californicus Buckley Pogonomyrmex sp. Quantity destroyed—Bees and wasps form 3.6 per cent of the yearly food. In no ease have ichneumon flies, which are valuable parasitic insects, been taken in numbers, five being the maximum found in a single stomach. Their rapid flight prob- ably prevents a greater toll being taken. Ants are often eaten in large quantities and form over two per cent of the food for the year. It is not an uncommon occurrence to find a stomach almost filled with ants. Over one hundred have been found in a single stomach. Economic importance—Most bees and wasps are considered beneficial insects. Ants are either injurious or neutral; few are beneficial. In the destruction of ichneumon flies the western meadowlark is destroying a valuable parasitic insect. The de- struction of bees and wasps must also be reckoned as a count against the bird. However, the small numbers destroyed mini- mize greatly the real and the possible damage done. The destruction of most kinds of ants makes little difference one way or the other, owing to their abundance and scavenger habits. Diptera (Flies) A few members of the family Muscidae, a few flower-flies (Eristalis sp.) and erane-flies (Tipula sp.) and the pupae of syrphid flies (Syrphus) are the only representatives of the Diptera which have been found in the stomachs of western meadowlarks. The following have been identified : 1914] Bryant: Economic Status of the Western Meadowlark 435 DIPTERA Eristalis tenax Lueilia caesar L. Tachina sp. Musea sp. Syrphus sp. ? Tipula sp. Quantity destroyed—Fles do not constitute any important percentage (about one per cent) of the food for the year and when found have been in small numbers. A few green bottle- flies and other members of the same family are eaten, as are also flower-flies and drone-flies. Birds collected at El Toro, Orange County, during 1911 had eaten large numbers of the pupae of flower-flies (Syrphus sp.). Crane-flies (Tipula sp.) are not taken as often as it would seem they would be from their abundance. Evidence is at hand, however, that western meadowlarks feed largely on the larvae when they become abundant. Mr. W. M. Hughes of Madera, Madera County, has made the following report: ‘‘When I visited the tract of land affected, I found myriads of blackbirds and thousands of meadowlarks on the eround making small holes into the ground at the roots of the plants and taking out the worm. Several hundred acres of fine erop was destroyed before the birds collected in numbers suffi- cient to destroy the pest.’’ The outbreak referred to was in the vicinity of Minturn, Madera County, in 1909. Several hundred aeres of barley were destroyed by crane-fly larvae at this time. Economic importance——In spite of the fact that the larvae feed upon decaying matter, most flies are considered pests be- cause some of them earry germs of disease. Green bottle-flies are disease carriers. The larvae of flower-flies feed upon plant lice and hence are considered beneficial. The larvae of crane- flies, on the other hand, are destructive to vegetation. The small numbers of flies taken and the fact that injurious as well as beneficial forms are eaten make the destruction of Diptera by meadowlarks of little consequence. Arachnida (Spiders ) Quantity destroyed.—Spiders and their egg-cases form less than one per cent of the food for the year. Most of the spiders taken are grass spiders (Agalenidae) and daddy-long-legs (Pha- 436 Unwersity of Califorma Publications in Zoology (Vou. 11 langidae), the commonest of those found in pastures. In no instance have more than two spiders been taken from the same stomach. Economic importance.—Spiders should be considered as doubt- fully beneficial or of neutral value to the agriculturist, in spite of the fact that they feed largely on insects. As a rule spiders are not abundant enough to be of great economie importance. Their destruction at the hands of the meadowlark is of no conse- quence, as the resulting effect on insect life is so small. Miscellaneous Animal Food Miscellaneous articles of diet form three and one-half per cent of the food for the year. The common sow-bug (Porcellio scaber) is the commonest erustacean found in stomachs. Two birds had eaten snails. Two birds from San Diego had each taken a scorpion. But few earthworms have been found in the stomachs. Centipedes (Scolopendra sp.) and millipedes (Julus) appear to form a constant part of the diet. They are evidently taken regularly where available. Two birds had eaten ant-lions (Myrmeleon sp.). Quantity destroyed—Centipedes, millipedes, scorpions, ant- lions, and sow-bugs may be considered oddities in the diet. Their slight availability may account in some measure for the small numbers taken by the western meadowlark. Economic importance.—Of these miscellaneous elements in the diet, only millipedes and sow-bugs can be considered injurious. Centipedes are usually considered beneficial, scorpions injurious, and ant-lions of neutral value. None of these forms is taken in sufficient quantity to make their destruction either an injury or a benefit. Inorganic Matter Pebbles, used for grinding the food, make up the imorganic matter found in the stomachs. White and red pebbles, probably beeause of their conspicuousness, predominate. Pebbles appear to be necessary as an aid to the digestion of grain, but much less necessary for the digestion of insects. Pebbles are nearly always 1914] Bryant: Economic Status of the Western Meadowlark 437 found with grain and weed seed, but seldom with insect food. Doubtless the chitinous parts of the insects largely take their place. Two nestlings and two adults contained parts of ege-shells. It is a well-known fact that birds often eat the broken shells after the young have hatched. In one instance, at least, the parent birds had fed the young on the shells. PRINCIPAL ARTICLES OF Dirt The kinds of food forming a definite part of the food of the western meadowlark for the year are as follows: ‘VEGETABLE ANIMAL Grain 80.8% Coleoptera 21.3% Weed seed 5.3 Orthoptera 20.3 Miscellaneous 6 Lepidoptera 12.2 Hemiptera Worl Hymenoptera 5.6 Diptera oil Arachnida 2 Miscellaneous insects 1.9 EXAMINATION OF FECES Other than stomach examination, the examination of feces would appear to give the best evidence as to the food of birds. That a considerable amount of knowledge concerning the food of meadowlarks can be obtained in this way is evidenced by the fact that the examination of feces of meadowlarks collected June 15, 1912, in the Berkeley Hills showed the following: Thorax of spider, heads of ants, mandibles and other parts of grass- hoppers, wing covers and mandibles of beetles and pubescence from wild oats. The examination of some feces collected from nestling birds at Lathrop, San Joaquin County, showed that these same hard parts passed through the digestive tract undigested. Conse- quently this affords a practical method of determining the kind of food taken. Its value as a means of determining the amount of food is much less, for only the more resistant parts can be found. ty of California Publications in Zoology \Vou.11 38 Universi « 4 pooy a[qB}a5aa [eJOT, oe S © poo [wuruE [BOT OO Ot vS §e L2E 66) 90) emers Is (hts Eh ap EE ities PGP a ie v ¥ 6S Le ¢ GLS GiGae Sa ¢ dig ts" [er eeece GL [i en ee Cie GiPSh = Sille IS meee yas 9ST SO ity SF i r6r Gg OST 9° ie ia Cree Lt TT % vv a 8 (VIE UT (a $06 9% i716 tale 9°8 8 GP Ee eee a en. Bae ii 9°9 G3 0% 6F i Miz (it A 0's - ¥ v Gr OL F9 eae mLogh GC Mae SiS SS ESice S| tae 8G Gal (ae bk Ms FST OL G86 9° i tol og fs 99 6 SSL 83 f 6 Gis GAS rate ee? 63L (alk SP ¢ LG & Cre ew L6 2 n > 20 ow a ast @ # bE & fee fy 2S S82 ¢ & gs gue 6 “Se ame 48 a @a Bas & go Soh F 5 O§ 52 ¢ EB s@8 2 os ° 2 he) oo >” us] 2 a Ls] 4 4p ne . & 2 > 2 as On vs ee g — A LS is S § MUVIMOGVATY NYALSA MW GHL dO GOO dO SAGNIM LNAYAMMIG AHL JO SAWNTIOA-ANVINGOUTG AVATAY— TT OT sjyoug @ & oS 66 o So[}I0 =) Deed = (e1aydoalop) a Lo! eh aq On & st © lor) rc peas PpaaM Sor Gos 8°SF LOS F'86 G0 uk ill i! ADMDoOr~ VHA AA TH oO Ann caro aot Lon! sqquom oS yo 1aquin a st ow OW Ww ao Ss oD a) + a or) a oD 0 rc S © Sparq II6L 6I6L LI6L TI6L LI6L II6L 6161 II6L TI6L TI6L Tl6. 6161 LI6L II6L LI6L II6L TI6L LI6L avaX poate SNBISTURIG SNBISIIIS Bpowely SBIIARTE) umbeor weg OJMIWIeLIVY OJUIUIRIIVG eden BPBAIN SBUIN[ 19}40g 19}4ng RUeYAL BULOTOg oulnopuayy NOATYSIG Fp loqurn Fy Aqunop 39 4 status of the Western Meadowlark eS yant: Economi 1914] Bin oy & poor aes A[(BJISOA [BIO], 8°69 os a ¢ 6 ST SL (aye) v Ls ZT LT OFS 6L9 Gs a L 8° U& FST 65 Eye) re a Gifling eau TF 6°66 Sige 2S 8° 9° g GLP 0°89 63 F0° oS OT 61 Law 8oL GG 8 v Coro tate) Ate) BSF es ¢ Ge fee GOL 6 8'6F SE Si v oT CT g 8°09 Lg is 9% GL tale FIL Oi6G SiS™ se (OE Ry ee ee 606 GiOle metas: TS [Eis eee 92 au BO eee eee ge os & ay gs Hee Ko Ss [he ey BS Son 8” gé 2 = on Ba B Leis) ES 5 7 ic) Ie Ss =| 5 2 re 5 = eae 5 es) ‘eh 5 as p> PapNOUOJ—MAVIMOGVA NUALSAM Qonra ol Lon! ¥) SJayouro wla[Usnia fr (ds snyoujad Ss -0Ua} s1addoysseiy or oi coor Kt aaa wmonoeoenn saeg DoS WO 15 15 Boor <# cl 3 (e1aydoea[op) poes paa\ ~ a co syyuour oy yo taquin yy t sH no rc spaq 2 oO =| JO LaquInN SosRIOAR pure s[eqoy, SNOIUR[[AISTL jereduy oso ueg asuvlg APISIOATY OUIpIBUleg, WRG BAINJUI A DeGD ss oAUT BlBqleg BIURy Agito} WO OJ TMOg uByg SHUTS Ouse. yy BLOPR IL Aqunoy GHL tO GOO dO SGNIM LINAYMMIG AHL JO SAWNTIOA-HOVINEONTG AVYFAY— TL 440 University of California Publications in Zoology |Vou- 11 QUANTITY OF Foop Three methods may be used in estimating the quantity of food in a bird’s stomach. First, the articles found may be counted; second, they may be weighed; or third, they may be estimated by volume. The first method, although important as giving an idea of the bird’s economic value by showing the number of injurious insects or seeds destroyed, fails to take into account the difference in size of the different articles, and does not show the relative amounts of each kind. The second method has been generally disregarded because of its impracticability. The third or vol- umetric method allows of a balance of the inequalities of size, and best portrays ‘‘the ratios each element bears to the others.’’ By the numerical method, fifty ants would be placed against, say, six ground-beetles. A computation made by the percentage- by-volume method would doubtless show that these two kinds of food represented only three and twenty-six per cent, respectively, of the whole food. Hence the idea furnished in the first case (a ratio of 50 to 6) is a misleading one. Numbers of one insect cannot be balanced against the numbers of another insect. As each bird of the same species has a certain average stomach capacity, the ratio of each element to this average capacity gives the most accurate idea of the relative proportions of each kind of food. Although the first and last methods have been those most often used heretofore, the second presents certain advantages (e.g., mathematical accuracy) which should not be overlooked. A combination of the numerical and the percentage-by-volume method has been used in the present work. The number of birds taking the different kinds of food offers further evidence as to their capacity for good or ill. McAtee (1912) has pointed out that statements of numbers of individuals in stomachs has an interest in direct proportion to the bigness of the number. Believing this to be largely true, the maximum number of individuals found in the stomachs has here received emphasis. These maximum numbers should not be considered as averages. 1914] Bryant: Economic Status of the Western Meadowlark 441 It does not seem fair to compare the food of a species of bird of small size with that of one of large size without taking into account the bird’s capacity. The degree of injury or benefit is largely dependent on the total amount consumed. In this investigation measurements in eubie centimeters of the stomach contents of a number of western meadowlarks have allowed the computation of the average stomach capacity. For male birds this average capacity is three cubic centimeters; for female birds it is two and one-half eubie centimeters. The average capacity is two and three-fourths cubie centimeters. This method allows of some interesting computations of the capacity for good or harm of the western meadowlark. If there are twelve meadowlarks to the square mile, as there are in many places, these birds demand over one hundred cubic centimeters of food daily. This capacity, estimated in grain, means 2200 kernels, in grasshoppers 150 average-sized individuals, in eut- worms 125 individuals, in ground-beetles 300, in ants 2500. As digestion is constantly going on, much larger numbers are in reality taken, as is evidenced by a count of the insects in a stomach. These numbers, therefore, are not even a minimum. As pointed out (p. 412), the results of the experiments showed that meadowlarks must completely digest a meal inside of four hours. It was also found that grain takes longer to digest than do insects. Thus it can be seen that the food found in the stomach at any one time does not represent the total amount of food taken daily, but only about a third part of that consumed daily. Owing to the slower digestion of grain, the amount found in a stomach must represent more nearly one-half of the daily requirement. Taking an average capacity of two and three-quarters cubic centimeters and considering that each bird fills its stomach at least three times a day, one hundred western meadowlarks must consume near a liter, or about a quart of food each day. If the food be grain it can be seen that the amount of destruction is considerable; if the food be insects it can be seen that meadow- larks take a large daily toll of insects. The same type of com- putation shows that a single western meadowlark must consume six pounds of food a year. 442 University of California Publications in Zoology (Vou. 11 Some idea of the average numbers of the common insects, grain, and weed seeds destroyed at each meal by western meadow- larks can be obtained from the following tables, which were computed from the results of stomach examination of birds col- lected in Sacramento and Stockton, California. the day is three times that for each meal. The average for NuMBER OF CoMMON INSECTS, GRAIN AND WEED SEEDS DESTROYED BY WESTERN MEADOWLARKS COLLECTED AT SACRAMENTO, CALIFORNIA Grain Le Oe oe PN de 3 3 4s Sees Cra if vate 8 ate 9 2 LOS Ges 1 I eeoaee 125 ee Uy aren V4 aes Totals 5 Avy. perbird 3 Grain ae ested By eee: Seams eres 4 al 5 2 Ca Use eee yh Fea 9 25 LOOP eee ee ye Totals 28 Av. per bird 2.5 February to April, inclusive Beetles 6 10 Cutworms and cater- Grass- pillars hoppers Bugs September to November, inclusive Weed seeds Beetles Cutworms and cater- Grass- pillars hoppers i 1 Breer 1 1 2 Ske 2 22 2 neds 11 meee 1 TS Aes Jaycee 10 25 30 2.2 2.6 Bugs Ants, bees, and wasps Spiders Ants, bees, and wasps Spiders 1914] Bryant: Economic Status of the Western Meadowlark 443 NuMBER OF INSECTS TAKEN BY WESTERN MEADOWLARKS AT STOCKTON, SAN JOAQUIN CouNTY, CALIFORNIA “ eS = ° oD 4 = B 2 Py 3 x 2 2) zB 2 = a Sa = o o io ° a 3 S Hh) food s a B iS a S s ee eee Gee ae Pyne cee. ee) ae ae aie Date 6 9 ) 5 is) es] del 4 > 15 March-June, 1912 6 25 88 52 88 68 4 7 4 311 31 Ay. per bird eA el OF Ocoee ot eu Os Oem sOl eae 04-0) 220 2.0 Av. per bird perday 1.2 4.8 17.4 10.2 17.4 13.5 6 12 .6 60.0 6.0 Few people have any realization of the great quantities of insects consumed by birds. For instance, if we consider that there is an average of one meadowlark to every two acres of available land for eultivation (11,000,000 acres) in the Sacra- mento and San Joaquin valleys and that each pair of birds raises an average of four young, each one of which averages one ounce in weight while in the nest and consumes half its own weight of food each day, it takes over 34314 tons of insect food each day to feed the young birds in the great valleys alone. The increased consumption of insect food due to nestling birds comes at a time when insects are most numerous, and so is instrumental in helping to prevent an undue increase of insects. As insects become injurious only when in maximum numbers, this increased con- sumption by birds is doubly important. A conservative estimate of the approximate amount of the different kinds of food consumed by the average meadowlark in California during a year is as follows: COTE 0 ce eeseeee ee See ee eee eee 1% lbs. SWIC COMSCO CM Ger. se Seat reer cee cs ec ceeescecsccet nee % Insects 23, Total The fact that the western meadowlark eats both animal and vegetable food is a point in its favor. If it were exclusively insectivorous the bird could not exist in such large numbers because of the lack of insect food during part of the year. The consequent destruction of inseet life would therefore be much smaller. 444 University of California Publications in Zoology (Vou. 11 Certain species of birds when hungry will not only fill the stomach, but will continue eating until the gullet is also filled. This is often found to be the case with linnets and bicolored blackbirds. In no ease, however, has the gullet of a western meadowlark been found well filled with food. At the most, the last insect taken before the bird was collected has been found in the lower part of the gullet. CapPAciTy FOR Goop or Evin AS EvipENCED BY THE NUMBER OF Birps TAKING THE DIFFERENT ITEMS OF Foop The percentage-volume method of estimating the proportion of the different kinds of food taken by a bird gives us the best idea of the relative importance of the different kinds of food in the diet of a given bird. However, the frequency of occur- rence of the different items in the food, shown by a statement of the number of birds taking each item, furnishes additional evidence as to the capacity of a species for good or ill. The number of birds taking a certain kind of insect food can be regarded as an approximate index of the availability of that kind of food, and to a much less extent as an index of food preference if we consider insects as being evenly distributed and birds as being but slightly influenced by psychological processes. A nearer approximation can be obtained by multiplying the number of birds by the number of insects taken. In such a computation the number of insects taken is considered, as well as the number of birds taking the different elements of food. By this method the index of availability of crickets at Live Oak, Sutter County, was four in 1911, whereas this index was 6902 at Hollister, San Benito County, in the same year. By the same method of calculation the index of availability of grasshoppers was 2162 at Live Oak and but 1541 at Hollister. In the first case crickets were 1670 times as available at Hollister as at Live Oak, and grasshoppers 1.4 times more available at Live Oak than at Hollister. The following table gives a comparison of availability of the commoner insects as evidenced by indices of availability. Preference is here classed as a factor in availability. 1914] Bryant: Economic Status of the Western Meadowlark 445 0S ~~ sorruoant Aq woe} sesezu0o1eg 0€ 1S6 196 tm 2 0G 0S sjjupe Aq wayez soseyusd10g ~ sottuaant Aq Uayey sioqunu [enyoy G6 Sl GSh 9% fe I AL tet} its 6 £96 O13 cy Number of S birds ~ sqyynpe Aq uoyey stoquinu penpoy me eee Grain Lis °' Weed seeds O16 Beetles iE > Crickets Grasshoppers — Jerusalem crickets o S Cutworms and caterpillars oo > Bugs = = Bees and wasps rss © Ants 2 Spiders : Vegetable + food SMUVIMOGVAJ, TYNTANL GNV LINdy Ad NGMV, GOOT AO SGNIYM GNANAdMIG AHL dO SADVINAOUTG INV SHdAaWAN TWOALOY—A --- Suryey spirq Fo esvyuoo1eg Surye} sprig JO 1aquny aw . Wireworms bo BBugs _ (Hemiptera) ran Cus Cicadas iS) bo to Ants S = Bees and wasps to “' Tchneumons No} = Butterflies x & Pupae [vs] * Plies a Fly larvae Crane flies —_ Spiders Toren or Spider egg cases fon) Centipeds oo Millipeds = > Sow bugs ~- Zurye} sparq FO oseyusd10q LVe PEL - Suryey Sparq FO soquNnN > Oats = o Barley or an to Wheat I Corn 10) Sorghum or Beans aw aw eed seeds a © Grape seeds “' Grass Beetles S Crickets eo Grasshoppers Jerusalem crickets on = Cutworms and caterpillars 9 0Z6T peunuexe 1oquinu [e4OJ, d00,jf dO SANIN GNANTHIIG ONIAV, SUI FO SANVGNAOUTA ANV SUIAWAN—SHAVIMOGVAN NYALSAA\ ‘Til 446 University of California Publications in Zoology |Vou. 11 INDICES OF AVAILABILITY OF COMMON INSECTS EATEN BY WESTERN MEADOWLARKS No. of Cut- Grass- Bees and Locality birds Beetles worms hoppers’ Crickets Bugs wasps Ants Live Oak, Sutter Co. 60 1,775 288 2,162 4 533 78 18 Hollister, San Benita Co. 60 4,307 7 1,492 6,680 197 265 35 The most available and the most popular food of the western meadowlark, if it may be judged by the frequency with which it has been found in the stomachs, is beetles. Seventy-five per cent of all the stomachs examined contained beetles (Coleoptera). Vegetable food in the form of oats is next in order of frequency, thirty-four per cent of the meadowlarks examined having taken oats as food. Grasshoppers, cutworms and caterpillars, and weed seeds were found in thirty per cent, twenty-six per cent, and twenty-five per cent respectively of the stomachs examined. The accompanying table gives a summary of the number of times each article of diet was taken and the percentage of each article in the diet of the species. Attention should be called to the fact that a very large percentage (seventy per cent) of the birds taking oats took wild oats (Avena fatwa) instead of the tame varieties. Consequently not more than ten per cent of the birds examined had taken cultivated varieties of oats. Although the percentages showing the proportionate number of times each kind of food is taken to the number of birds exam- ined differs from the percentages showing the proportionate vol- ume of each kind of food, yet they parallel each other to a considerable extent. The accompanying table, giving only the principal articles of diet, shows this parallelism in the per: centages. TV.—PERCENTAGE-VOLUME AND PERCENTAGE OF WESTERN MEADOWLARKS TAKING DIFFERENT ELEMENTS OF Foop n ee =~ ’ rg 2 aye g 2 S = Ee Cu ick 1G = = g 2 iF 5 & 6 Ge oe E 5 S aa iS S fa = rien matata xl oF Percentage-volume .. 30.1 99 17.0 3.5 18.0 3.1 3.0 4.0 ell 2 Percentage of birds Greaves Goseeceenee soe A610) 25109 Oib:2) eee 085s eel S ee Gree os eee lm] 1914] Bryant: Economic Status of the Western Meadowlark 447 Foop or NESTLINGS Three methods are available for determining the food of nestlings; first, the rate of feeding may be determined by watch- ing the number of trips made to the nest by the adult birds while feeding the young; second, the young birds may be made to disgorge their food; or third, the bird may be killed and the food in the digestive tract examined. The first method has not been used with any great degree of suecess because of the diffi- culty in approaching near enough to the nest to observe the feeding. The western meadowlark does not become accustomed to an intruder so easily as do other birds. The food observed in the bills of adult birds carrying food to their young has most often been cutworms or grasshoppers. One female bird, while feeding, persistently flew into an oat field and returned each time with cutworms. Another female bird was seen to catch three or four grasshoppers in her bill, and then fly to the nest. Examination of the digestive tract of nestling birds has shown that they are fed very largely on cutworms, grasshoppers, and ground-beetles. The stomachs of two nestlings obtained from the same nest contained egg-shells. This is not an unusual oecur- rence, for nestling birds of other species are fed on the egg-shells. In no ease was grain found in the stomachs, and in only a few cases were weed seeds found. Young birds doubtless need a larger quantity of food than adults. In almost every case the stomachs were average full or over. This means that each stomach contained nearly three cubie centimeters of food. Since it has been shown that young birds need over one-half their own weight of food each day, the birds when hatched must consume about one-fourth of an ounce a day, and when ready to fly about two ounces. This increased consumption of insects due to the demands of young birds comes at a time when there are growing crops which need protection and when insects are most numerous, thus emphasizing the value of birds as balancers. The fact that meadowlarks show a greater preference for certain kinds of food while feeding the young enlarges their sphere of usefulness. In spite of the fact that a certain amount of grain and weed seed is available, young nestling birds are fed almost entirely 448 University of California Publications in Zoology [Vou. 11 on insects. It would seem, therefore, that there is a certain preference for insect food shown at this time of the year. It is a well-known fact that many adult birds which feed on weed seeds feed their young almost entirely on insects. It seems safe to say, therefore, that the western meadowlark, when feeding the young, turns its attention to insects. The accompanying table (Table V, p. 445) gives a comparison of the food of fifty juvenile and fifty adult western meadowlarks. VARIATION IN KIND OF Foop The kind of food taken by the western meadowlark is de- pendent upon two cycles, the individual cycle and the environ- mental cycle. The individual eyele includes such factors as individual taste, time of feeding, and the preference for a particular locality. In fact, all of the factors which depend upon the individual tastes or habits of the bird are grouped here. Whether an individual bird has a particular taste for a certain insect, it is impossible to determine without experiment. Since we find different indi- viduals showing different characteristies, we can safely infer that each individual may show a slight preference for one kind of food above another. Then, too, the time during which the bird feeds has some effect upon the availability of certain kinds of food, so that we should naturally expect that the kind of food would be governed to some extent by the time the bird chooses for feeding. The particular locality frequented by the bird must also influence the kind of food taken. The food of a bird feeding entirely in a grain field would certainly show a slight variation from that taken by one living entirely in a pasture. The environmental cycle takes into account the changes in the availability of insects and seeds, due to seasonal and climatic conditions. The maximum supply of weed seed is available dur- ing September and October. The maximum supply of insects is apparently available during May and June. Even the culti- vation of land has much to do with the availability of certain kinds of food. Many weed seeds are easily obtained during September and October, which, after plowing begins, are hidden 1914] Bryant: Economic Status of the Western Meadowlark 449 beneath the soil and so made unavailable. This helps to explain why birds feed so largely on grain during the winter months. Grain is far more available in cultivated districts at this time than weed seed. In some localities even a daily eyele may be noted. Certain insects appear in larger numbers after the sun has warmed up the soil. Certain insects, such as cutworms, are found in greater abundance before sunrise. Thus we might uaturally expect that birds collected early in the morning would have taken a larger percentage of cutworms than birds collected later in the day. Stomach examination has substantiated this as a fact. The kinds of crops raised in any particular locality must also influence the kinds of food taken, for it changes their avail- ability. For instance, the stomachs of several meadowlarks con- tained Egyptian corn and milo maize. Where this crop is raised to any extent the meadowlark doubtless occasionally turns its attention to this type of grain. In other localities where only oats and barley are grown these grains are the only ones available. VI—PERCENTAGES OF Foop OF MEADOWLARKS TAKEN IN ALFALFA FIELDS IN THE Vicinity OF HANFORD, CALIFORNIA Number Per cent Animal Vegetable eut- eut- Number Per cent matter matter worms worms beetles beetles Miscellaneous 1 CX) eee 3 50 4 15 1 potato-bug 2 96 4 2 30 7 46 1 potato-bug, 1 bee 3 MOO a =e 25 80 9 20 4 98 Pests ce RRE 1 6 1 potato-bug 5 OOM e- 5 65 2 12 1 fly, 3 ants 6 96 4 19 76 6 20 7 MOQ co. 9 60 if 20 10 ants 8 88 12 23 75 4 10 1 fly 9 85 15 1 10 7 75 10 94 6 21 83 2 8 1 pupa 11 100m = 2 80 2 20 12 OOM Yess il 16 10 76 1 fly 13 TOO!) eter 4 55 6 20 17 small flies 14 WOO) ee 4 85 3 15 15 17 83 2 10 1 4 1 ant 16 IO) | Pees 8 60 5 14 1 cricket, 2 ant-lions Totals and averages 92.1 oe 29 52.1 76 24.3 16.1 450 University of California Publications in Zoology \Vou. 11 Stomach examination has clearly demonstrated the fact that birds collected in alfalfa fields consume much larger quantities of cutworms and caterpillars than birds collected in grain fields in the same general locality. The following table computed after the examination of sixteen stomachs of meadowlarks collected in alfalfa fields in the vicinity of Hanford, Kings County. Cali- fornia, clearly brings out the increased percentage of cutworms and eaterpillars in the food taken by birds in such fields. An- other table showing a comparison of the food of thirty-four birds collected in the above locality, but in different kinds of fields, brings out the same point. VII.—ComPariIson OF Foop TAKEN BY WESTERN MEADOWLARKS COLLECTED IN ALFALFA FIELDS, GRAIN FIELDS, ORCHARDS, AND VINEYARDS Averages of nine birds per month collected in March, April, and May, 1911, at Hanford, Kings County, California Average number of Per cent Per cent Percent Average ecutworms cutworms Kind of animal vegetable numberof Per cent and cater- and cater- field food food beetles beetles pillars pillars Alfalfa 95.9 4.1 5.1 24.1 11.2 61.4 Grain 99.4 6 9.4 58.5 1.8 21.0 Orchard 98.3 1.7 4.8 31.7 6.5 55.7 Vineyard 78.3 21.7 oll 5.0 7.0 42.0 VARIATION OF Foop AccoRDING TO TIME OF YEAR Abundant data have allowed a comparison of the food of the western meadowlark by the hour, day, week, month, and year. Little change in kind of food can be noted from one time of day to another unless birds were taken in different localities. Never- theless, the quantity of food found in the stomachs varies with the time of day. The maximum is found about nine o’clock in the morning, and the minimum from one to two o’elock in the afternoon. The same can be said of the food from day to day. A comparison of the food from week to week, however, shows considerable change. The change from week to week (and the same ean be said of the change from month to month) closely parallels the avail- ability of the different articles of diet. Weed seed and waste erain are nearly always available during September or October. 1914] Bryant: Economic Status of the Western Meadowlark 451 Yet if enough grasshoppers and ground-beetles are available, the birds evidently take these in preference, for stomachs are more often found filled with insects than with weed seeds. The accompanying diagrams illustrate the great change in food habits from one time of year to another. It will be noted in each instance that the food of the western meadowlark is made up largely of insects during the spring and summer months and largely of grain and weed seeds during the fall and winter months. It is needless to point out that this parallels the avail- ability of inseet food, and to a less extent the availability of vegetable food. In that the percentage of animal food for the year is greater than the percentage of vegetable food, and since some insect is nearly always found in stomachs filled with grain Animal food Vegetable food Jan. Feb. Mar. Apr. May June . s i July Aug. Sept. Oct. Nov. Dec. r Total Fig. C_—Diagram showing change of food habits of the western mead- owlark from month to month. Note that the maximum consumption of animal food is to be found in May, June, and July, and the minimum, corresponding with the maximum of vegetable food, in January and February. Computed from the results of stomach examinations of an average of twelve birds taken each month of the year at Red Bluff, Tehama County, California. and weed seeds, whereas grain and weed seeds are far less often found in stomachs filled with insects, it seems safe to say that animal food is preferred and vegetable food is used as a make- shift. The diagram showing the food of western meadowlarks col- lected in the vicinity of Red Bluff (fig. C) illustrates this pref- erence for insects. Ninety per cent of the birds examined were 452 University of California Publications in Zoology (Vou. 11 collected in grain fields, and yet the only time when they turned to grain was in the winter, when the numbers of insects were at a minimum. Evidently grain fields furnish an abundant supply of animal food during most of the year. The maximum con- sumption of animal food is in June and the minimum in January. The minimum of animal food corresponds necessarily to the maximum in vegetable food. The diagram showing the proportion of the two kinds of food of birds taken in the vicinity of San Bernardino (fig. D) lacks some of the inaccuracies to be noted in the former diagram. The maximum consumption of animal food is in April instead of May, due to the difference in climatic conditions. The birds taken in this locality, although collected largely in grain fields, consumed an unusually large proportion of animal food during 1911, more, in facet, than any other series of birds collected in southern California. The amounts of food taken by meadowlarks collected every two weeks at Newman, Stanislaus County (fig. E), also clearly brings out the change in food habits from one part of the year to another. The averages of the different kinds of food for the year do not change greatly from one year to another. The time of year when the different kinds of food reach a maximum in the diet Fig. D.—Diagram showing change of food habits of the western mead- owlark from month to month. Note that the maximum consumption of animal food is in April and May. Computed from stomach examinations of an average of six birds collected each month in a year at San Bernar- dino, San Bernardino County, California. 1914] Bryant: Economic Status of the Western Meadowlark does change. the available food supply. 453 This seems natural, for weather conditions affect Thus we find very few ants taken by meadowlarks collected at Newman, Stanislaus County, in 1911, but large numbers taken during the same months in 1912 (fig. E). Animal food Total Fig. E. Vegetable food Diagram showing the comparative amounts of the different kinds of food of the western meadowlark every two weeks during a year. Computed from the results of stomach examinations of birds collected at Newman, Stanislaus County, California. The following table gives a comparison of the amounts of animal and vegetable food and the amounts of some of the common elements of food taken by meadowlarks at Newman, Stanislaus County, in 1911 and in 1912. The difference amounts of animal and vegetable food is seven per cent. in A large increase in 1912 of the number of grasshoppers taken can be noted. Seventy-two birds from each year were examined. COMPARISON OF Foop OF MEADOWLARK FOR Two SUCCESSIVE YEARS Per cent Per cent Per cent animal vegetable Per cent grass- Percent Per cent Year food food g hoppers beetles ants 1911 S85) 46.5 27.5 8.5 A 1912 65.7 34.3 42.4 9.9 3.0 454 University of California Publications in Zoology (Vou. 11 VARIATION OF Foop Hasrrs Accorpine to Locaniry The comparison of the food of the western meadowlark in California has been made in several different ways. As soon as it was found definitely that the food varied greatly from one part of the state to the other, it was decided to make three group- ings for comparison as follows: (1) districts; (2) counties; (3) localities. The wide difference in the kind and availability of food in the coast region and in the interior valleys makes this comparison of prime importance. Although a comparison by counties covers in a measure that by districts, yet this smaller unit of area brings to each rancher a knowledge of the food of the meadowlark in his own county. Although the difference in locality will parallel largely the difference in county, owing to the fact that usually but one series of birds was collected in each county, yet this comparison affords a knowledge as to the amount of variation between still smaller units of area. Birds collected in the vicinity of San Diego took a smaller percentage of insects than those collected at Riverside and San Bernardino. Birds collected in the vicinity of Ukiah, Mendocino County, took larger numbers of click-beetles than birds from any other locality. Stomachs of birds collected in the vicinity of Hollister, San Benito County, contained extraordinarily large quantities of crickets. At Hanford, Kings County, birds fed very extensively on cutworms. Birds collected at Newman, Stan- islaus County, contained extra large percentages of stink-bugs and grasshoppers. Birds from Red Bluff, Tehama County. Live Oak, Yuba County, Sacramento, Sacramento County, Newman. Stanislaus County, and Los Banos, Merced County, took very nearly the same proportion of animal and vegetable food. VARIATION OF Foop AccorDING TO DisTRICTS For the purpose of comparison the following county groupings were made: Humid Coast Belt: Humboldt, Mendocino, Sonoma, Marin. Interior Valleys: Tehama, Sutter, Sacramento, San Joaquin, Alameda, Merced, Stanislaus, Madera, Fresno, Kern, Kings. Mountain District: Shasta, Lassen, Nevada, Calaveras. Arid Coast Belt: Ventura, Los Angeles, San Bernardino, Riverside, Orange, San Diego. Desert: Inyo, Imperial. 1914] Bryant: Economic Status of the Western Meadowlark 455 The following table gives the food of the western meadowlark in these districts: TABLE SHOWING VARIATION OF Foop AccorDING To DisTRICTS Number Per cent Per cent of animal vegetable birds food food Helo COast BS elit ececsce-see ee 99 59.0 41.0 Tmiberion walleys: 22-c.ccce see corse 785 61.8 38.2 Mountain district - 27 69.6 30.4 Arid Coast Belt 536 58.5 41.5 WESCT bye tes ccc ee 58 63.0 37.0 By considering only those localities where complete or nearly complete series were obtained, a still more marked difference could be noted. If the results from an examination of more birds from the humid coast belt and mountain districts were available, the results would show a larger amount of animal food. The remarkable thing is that, considering the widely different climatic conditions, the food averages do not vary more than ten per cent. INFLUENCE OF AGE AND SEX ON QUANTITY OF Foop TAKEN As the male weighs an ounce (28.35 grams) more than does the female, a difference of one-half cubic centimeter in capacity is accounted for. Juveniles average less food than adults. This is explainable on the ground that they are less experienced in obtaining food. Male and female nestlings apparently have more nearly the same capacity than do adults of different sexes. A slight variation has been noted between the food of adults and young birds, both in kind and quantity. Young birds ap- parently lack the experience of the adults and pick up only the more conspicuous insects and weed seeds. They also lack the experience needed for catching certain insects, and therefore the stomachs average a little less in volume of food. It has been pointed out by Finn (1887) ‘‘that each bird has to separately acquire its experience, and it well remembers what it has learned.’’ There appears to be little instinctive knowledge of the different kinds of food, and each young bird must test and learn. It would seem, therefore, that young birds would collect many so-called protected insects, whereas some experienced ones 456 University of California Publications in Zoology [Vou. 11 would pass them by. This theory has not been supported by the results of this investigation, nor, on the other hand, has it been broken down. Although young birds were distinguished from adults, yet the unusual insects found were not constantly taken from the stomachs of young birds. COMBINATION OF FIELD AND LABORATORY WoRK Judd (1901) has suggested, as the best means of determining the food of birds, an examination of the available food supply combined with stomach examinations of birds taken in the same locality. There are many points which commend this method. Yet there is great difficulty in determining the available food supply. Even an experienced observer cannot estimate even with moderate accuracy the comparative numbers of insects and weed seeds in any given locality. A bird is able to see many articles of diet which such an observer doubtless overlooks. Let me cite a case in point: A meadowlark was seen to fly to a grain field and collect cutworms to feed its young. Careful investi- gation by me of the place where the cutworms were collected failed to reveal any. The same was noted with a pair of Brewer blackbirds who persistently collected cutworms in a_ pasture. Continued investigation in the same pasture did not allow of the collection of a single cutworm. An attempt was made to follow this particular line of investi- gation, but was finally given up on account of the multitude of personal errors which are easily introduced. It seemed best to concentrate on the usual method of stomach examination, thereby making comparison with previous work possible. RELATION OF Birps To INSECT OUTBREAKS The value of birds as insect destroyers is more noticeable at the time of an insect outbreak. Their importance in maintaining an equilibrium depends largely upon their effect when insects oceur in abnormal numbers and thus become noticeably injurious. In two insect outbreaks investigated the western meadowlark was found to take a very active part in insect destruction. 1914] Bryant: Economic Status of the Western Meadowlark 457 During the spring and summer of 1911 the nymphalid butter- fly Eugonia californica beeame very abundant in the northern part of the state. Since butterflies are seldom eaten by birds, the outbreak afforded a splendid opportunity to study the food habits of birds. Consequently an investigation was carried on during the latter part of August at Sisson, Siskiyou County, California, when these insects were in abnormal numbers. Apparently because of the availability of the insect, several birds were found to be destroying butterflies. The Brewer black- bird (Huphagus cyanocephalus) fed on them almost exclusively, whereas the western meadowlark (Stwrnella neglecta), western kingbird (Tyrannus verticalis), blue-fronted jay (Cyanocitta stellari frontalis), and Say phoebe (Sayornis sayus) took them sparingly. A comparison of the food of birds taken before the plague with that of birds taken while the plague was at its height showed that birds had varied their food habits and had taken advantage of the abundant supply of insect food in the form of butterflies. Both observation and stomach examination showed the western meadowlark to feed on the butterfly (Hugonia californica). A lone meadowlark feeding with some Brewer blackbirds on the grass plot adjoining the station at Sisson was seen to run after several butterflies and to catch one. In the examination of seven stomachs, two contained butterflies. Fifteen and two-tenths per cent of the food taken by the five meadowlarks collected in August was made up of butterflies. All of these birds were taken in meadow or cut fields of wild hay where other insect life was abundant. Beetles and grasshoppers formed the bulk of the food. Stronger evidence that birds turn their attention to the insect most available can hardly be found, for in this case we find a supposedly unpalatable insect becoming food for a number of species of birds. The United States Biological Survey, in the examination of more than 40,000 stomachs, has found but four records of birds eating butterflies, ‘‘and one of these probably relates to the capture of a very recently emerged specimen, or to one torn from the pupa before emergence, as it was accom- panied by a pupa of the same species.’’ (See McAtee, 1912c.) 458 University of California Publications in Zoology (Vou. 11 Whether butterflies are too active to be caught, or whether they are unpalatable because of odor or taste, are questions still await- ing an answer. In any ease it can truly be said that butterflies, considering their abundance, are not taken as food in anywhere near the proportion that other insects are taken. That four of the larger common birds of the region should have fed upon these insects and that one of these should have fed almost entirely upon them is certainly significant. It cannot be said that lack of other food caused these birds to turn their attention to butterflies, for many of the birds col- lected had either taken no butterflies or but one or two. The butterflies were not only conspicuous, but extremely abundant. Some idea of their numbers ean be obtained when it is known that in damp places or along the banks of streams, where the butterflies had gathered to drink, as many as one hundred and fifty individuals were counted in one square foot. In order to estimate the numbers flying counts were made of the individuals passing between two fir trees about twenty feet high and standing about thirty feet apart. The counts for ten successive minutes between 4:40 and 4:50 p.m. on August 20, 1911, were as follows: il stiminitele eee 105 velo Resa ON) ences 96 2nd minute! 22. 119 8th minute .............. 102 OT Gaming eset eeeee 130 CChrlay weabuoNba Sy eee 83 4th minute .............. 102 10th minute ............ 112 5th) minute! -22---—--- 13 GGheminuite: eee 100 Av. per minute . 108 It can readily be seen, therefore, that butterflies were the insects most available at the time. The significant thing is that certain birds changed their food habits to meet the changed con- ditions. Birds collected in the same locality before the butter- flies became abundant had taken no butterflies. The investigation did not show that birds can be depended upon to control butterfly outbreaks, for the numbers taken com- pared with the actual numbers of the insects were insignificant. The fact that the birds attacked the insect at a critical time in its life-history—the adult stage when the death rate is at its minimum and the insect has the best chance of surviving till egg- laying—made the work of birds more important than if they 1914] Bryant: Economic Status of the Western Meadowlark 459 had fed upon the larvae or pupae. However, any increased de- struction at the time when insects appear in abnormal numbers must be considered a benefit. Four out of the five birds found to feed on the butterflies are numbered among the birds whose usual food habits justly subject them to severe criticism from the farmer. Consequently the conclusion can be drawn that some of the birds noted for their depredations often become valuable insect destroyers at just the time when they are most needed as such. This evidence fails to support Mr. MeAtee’s contention that ““butterflies are in very little demand with birds in the United States.’’ Nor, on the other hand, does it support the conclusions of Finn (1897) that ‘‘there is a general appetite for butterflies among insectivorous birds, even though they are rarely seen when wild to attack them.’’ Middle ground seems to be the best position to assume until more evidence is at hand. In our attempt to explain why butterflies are seldom taken by birds we have laid emphasis on palatability. This factor ean at best be but one of many factors, many of which are perhaps just as important if not more important. Then, too, it should be noted that palatability is an extremely variable factor, for it varies with the species, the time of year, the availability of food, ete. We still need a full examination of all of the factors governing the food-taking of birds in order to explain the inter- relation between birds and butterflies. In an investigation of a grasshopper outbreak at Los Banos, Merced County, in July, 1912, it was found that western meadow- larks were destroying an average of nearly fifty grasshoppers a day. From point of numbers and average number of grasshop- pers destroyed, the western meadowlark was, next to the bicolored red-wing, the most efficient destroyer of the pests. Meadowlarks averaged more grasshoppers per bird and were outdone by the red-wings only when the numbers of individual birds and the total destruction accomplished by each species were considered. A comparison of the food of meadowlarks taken in the same locality in 1911, when grasshoppers were not so abundant as they were in 1912, demonstrated the fact that meadowlarks averaged more grasshoppers when these insects were abnormally abundant 460 University of California Publications in Zoology [Vou. 11 than they did when they were not so abundant. The results of stomach examinations follow: Foop oF WESTERN MEADOWLARK AT LOS BaNos, Mercep County, CALIFORNIA Average no. of Total grass- per cent Number Animal Vegetable hoppers grass- of birds Date food food per bird hoppers 10 July 11, 22, 1911 99.0 1.0 7 83.1 5 July 15, 17, 1912 99.2 8 16 96.2 Meadowlarks took very nearly the same percentage (99, 99.2 per cent) of animal food each year at the same season, showing that at this time of year the bird is almost wholly insectivorous. The availability of grasshoppers as a diet appears to have influ- enced the birds taken in 1912, for they averaged sixteen grass- hoppers apiece as against seven taken by birds collected in 1911. As the numbers of grasshoppers in 1911, compared with the numbers in 1912, is not definitely known, it is impossible to state whether these birds changed their food habits in response to the extreme availability of the insects in 1912. It is also impossible to state whether the numbers taken in 1912 were in direct pro- portion to the numbers taken in 1911 or whether they failed fully to respond to the change in insect population. The fact remains, however, that meadowlarks, and other birds as well, took greater numbers of grasshoppers when they were abnormally abundant, but also forsook certain articles of diet, such as beetles and weed seeds, thus causing an inereased percentage of grasshoppers to be taken as food. The direction of the change of food habits was certainly coincident with the direction of change in food supply. The efficiency of a bird as an insect destroyer at the time of an insect outbreak is governed more largely by the numbers of birds than by their individual capacity. This was conclusively shown in the investigation of the grasshopper outbreak. The comparative destruction of grasshoppers per day by single indi- viduals and by the total number of each species is represented in the following table: 1914] Bryant: Economic Status of the Western Meadowlark 461 COMPARATIVE DAILY DESTRUCTION OF GRASSHOPPERS BY BIRDS Average no. of grass- Relative hoppers per day by destruction by different species One Total represented Species Class bird population by lines Anthony Green Heron B 42 1,050 Kildeer B 33 5.445 Burrowing Owl A 84 1,260 Western Kingbird D 8 1,280 Black Phoebe D 9 180 California Horned Lark D 8 8s Bicolored Red-wing B 29 78,590 Western Meadowlark B 48 24,720 Bullock Oriole B 45 4,050 Brewer Blackbird D 9 225 English Sparrow D 2 100 Cliff Swallow D 3 2,265 California Shrike C 12 1,200 Destruction per square mile by total oindiypop Ul acon s esses nner 120,458 Class A represents birds taking an average of over 50 erass- hoppers per day; class B, 25-50; class C, 10-25; and class D, fewer than 10 grasshoppers. The comparative numbers of the different species were caleu- lated by averaging censuses taken and by using the average per mile as a multiplier. Although not accurate, the table never- theless demonstrates the fact that such birds as the bicolored red-wing and the western meadowlark, birds of small capacity, because of their greater numbers, far outrank in efficiency birds with larger individual capacity. The fact that the western meadowlark, or any bird, turns its attention to the insect most abundant only emphasizes its value as a balancer. If meadowlarks took no greater proportion of insects when they are in abnormal numbers than when they were in normal numbers, they would play a decreasing part in restoring a balance. Since they do change the proportions of food to meet the fluctuations in the number of insects, they must be consid- ered an important factor in the restoration of normal conditions. 462 University of California Publications in Zoology [Vov. 11 A great number of factors operating together determine the abundance of an insect. Birds and other natural enemies are but one of these many factors. The rate of reproduction and food supply are probably more important factors. In spite of this fact birds are one of the limiting factors and are deserving of attention as such. The following facts have been demonstrated by these investi- gations: 1. Birds cannot be considered a dependable means of com- pletely controlling all insect outbreaks, but can be inferred to be instrumental in the prevention of many. 2. Birds can be depended upon to act as defenders and pro- tectors of crops because of their warfare against insect pests. 3. Birds change their food habits and feed on the insect most abundant, thereby making themselves important maintainers of the desired balance in nature. 4. The failure of birds to check an insect outbreak entirely is evident to all. Their success in preventing insects from be- coming abundant is not so apparent, but is none the less real. All obtainable evidence points to the fact that the regulative influence exerted by birds when insects are to be found in normal numbers, though less apparent, is none the less important, for at such times artificial control measures are seldom used. 5. Birds, which on account of their abundance cause serious losses to the agriculturist, often become for the same reason the most efficient insect destroyers at the time of an insect outbreak. 6. Birds help to maintain an equilibrium in nature. Their destruction, therefore, causes a dangerous disturbance of that balance of nature most suited to mankind. VERDICT OF RANCHERS In order that the opinion of the men most directly concerned might not be overlooked, a circular letter was sent out to promi- nent ranchers throughout the state. A copy of the letter follows: DEAR SIR:— The State Fish and Game Commission has taken up the study of the meadowlark in its relation to agriculture and desires to know what you think of the bird. In order to secure comprehensive and uniform data, answers to the following questions are urgently requested: 1914] Bryant: Economic Status of the Western Meadowlark 463 . Address SO) COUP SLUT OT mere eneanne eencecn eee enaeen crreatmenrass . How many acres of land do you own? .... Is your ranch hilly upland or bottom land? 5. What is the principal crop raised? What other crops? 6. Has the meadowlark done any harm on your place? Hee SO sm Oswva apn Cin bOMswLeL tn OK(b OTN 8 reese seen eee errr eens oee ene seemanre= . Have you examined the stomachs of any meadowlarks to ascertain their POOG IE) oo sceccenccecsn--= If so, what was in the stomachs? ................---.-----++- 8. Approximately, how many meadowlarks are seen daily on your place? Be i Are the numbers any greater when the grain is sprouting? 9. Do you prize the meadowlark as a song bird? _. 10. On the whole, do you consider the meadowlark a nuisance? ~.............-- ae Any additional information that you can give on the subject will be appreciated. Address all communications to H. C. Bryant, Assistant State Fish and Game Commission, East Hall, University of California, Berkeley, California. Over a hundred replies to this letter were received. Although the returns may be criticised on the grounds that a greater number of those interested in the bird because of its esthetic value sent in answers, yet care was taken to avoid this. Blanks were sent to the men who complained of the depredations of the meadowlark and to ranchers irrespective of their particular point of view. The average acreage of the men reporting was 638, so that it can be seen that the verdict is not from small land-holders or orchardists. Over ninety-eight per cent of those reporting grew grain or hay. When the returns as to whether the meadowlark is a nuisance and as to whether it damages crops are classified as to counties the results are as follows: Is the meadowlark Does the meadowlark a nuisance? damage crops? Number County reporting Yes No Yes No Siskiyou Gye | eee By eens 5 Shasta Dy cca ei Lee 1 Humboldt Py cee a ae 2 Trinity 1? a ee re 5 5 Mendocino 1 Tehama 3 2 1 2 1 Sutter 5 464 University of California Publications in Zoology (Vou. 11 Is the meadowlark Does the meadowlark a nuisance? damage crops? Number County reporting Yes No Yes No Plumas Ne ety este: be es eee 1 Butte 2 Pa Pec Dy it phe Yolo 1 Th (gy slates eS) taedies Sonoma 4 Ge eee ive Napa 2 1 1 1 1 Sacramento 2 1 1 1 1 Marin Ht qlee oak Fe 1 is) Dewees Contra Costa iv Lo 4 Oaees ee yf 1 Alameda U 2 4 3 4 San Joaquin 17 11 5 11 6 Stanislaus Di ee De sae 2 El Dorado 1 Wastes 1 ees Calaveras 1 eee 1 Madera 1 ee eis Do eee Merced SP ez 2 iL 2 Fresno 5 4 1 4 1 Monterey 9 2 i 2 6 San Luis Obispo 1 1 ee it | dass Kings 5 3 1 4 1 Tulare 4 J ye TE 3 i Mono BM ay hese Se ee eee 3 Inyo 9 2 7 2 7 Kern I OSS) ee i Sie: 1 Santa Barbara Sif Bee Sa ie Pees 3 Wentinra: 9 Oo cre ge FPS eg Ste ey ee Los Angeles 2 Tig dy eee eee 2 San Bernardino i eee 1 a eee ere 1 Orange bm ee a ee 5 Riverside 4 1 3 2 2 San Diego Ze Bees Be 2 Imperial ee ee et Sry) b ceteee Totals 122 48 65 54 67 Total coast counties 31 5 25 5 25 Total central counties 60 35 19 38 22 Total northern California 105 47 50 52 52 Total southern California 17 1 15 2 15 1914] Bryant: Economic Status of the Western Meadowlark 465 It will be seen from this table that there is a considerable difference of opinion as to whether the western meadowlark damages crops. The astonishing fact is that many grain growers in the Sacramento and San Joaquin valleys report that western meadowlarks do not injure their crops, or that the injury is negligible. The kinds of crops reported as being damaged ranged from garden truck, melons and grapes to corn and sprouting grain. Damage to garden truck, melons and grapes was reported by three or fewer men. Damage to oats was reported by over twenty, barley by less than this number, and wheat by less than ten. Most of the reports did not designate the kind of grain, simply stating that meadowlarks damaged sprouting grain. An- ‘ swers as to the extent of damage varied from ‘‘none’’ to ‘‘total ? erop.’’? The number of meadowlarks seen was reported as being from two or three up into the thousands. The answers to this question cannot be considered reliable. A large majority of those who considered the meadowlark a nuisance answered the question whether the meadowlark was prized as a song bird in the nega- tive, whereas those answering the former question in the negative almost unanimously answered the latter in the affirmative. Reports of damage were most numerous from-the Sacramento and San Joaquin valleys. This seems natural, for grain is the crop most widely grown in this section and meadowlarks are most numerous. Southern California is most unanimous in its verdict of ‘‘not guilty.’’ Two reasons can be made to account for this: the comparatively small amount of grain raised and the comparatively small number of meadowlarks. Few reports of damage have come from the northern coast region, in spite of the fact that meadowlarks are very numerous in this section. The majority of those reporting have not had crops damaged by meadowlarks and do not consider the bird a nuisance. It does not seem reasonable to believe that all of these men based their report on sentiment. Evidence seems to point rather to the fact that many of those complaining of damage have based their judg- ment on circumstantial evidence and have somewhat exaggerated the real damage done. 466 University of California Publications in Zoology (Vou. 11 A DETERMINATION OF THE ECONOMIC STATUS OF THE WESTERN MEADOWLARK IN CALIFORNIA Field investigation of the damage to crops has led to the following conclusions: 1. The western meadowlark is destructive to sprouting grain because of its habit of boring down beside the sprout and pulling off the kernel. The amount of damage varies with the location, the abundance of the birds, the time of year, the character of the soil, and the kind of grain. The damage to oats is greatest; wheat suffers less and barley little. A greater loss can be ex- pected with broadeasted grain than with drilled grain, because not being sowed so deeply it is more readily obtained by meadow- larks. The real amount of damage done has evidently been overestimated, however, for fields apparently badly damaged have given the average yield later in the year. On the other hand, where meadowlarks are very numerous and the quantity of grain small, fields have had to be resown to assure a crop. 2. In the destruction of sprouting grain we have the only serious count against the meadowlark, for damage to melons, erapes and other crops has been found to be negligible.