Taxonomy and Identification of STEAMER-DUCKS (Anatidae: Tachyeres) Bradley C. Livezey and Philip S. Humphrey u^C ^^, ^ Ernst Mayr lArary - P ^ ^ %weiim of Compara»ve Zoology Harvard University THE UNIVERSITY OF KANSAS. MUSEUM OF NATURAL HISTORY PUBLICATIONS The University of Kansas Publications. Museum of Natural History, beginning with volume I in 1946. was discontinued with volume 20 in 1971. .Shorter research papers formerly published in the above series are now published as The Universitv of Kansas Museum of Natural History Occasional Papers. The University of Kansas Museum of Natural History Miscellaneous Publications began with number 1 in 1946. Longer research papers are published in that series. Monographs of the Museum of Natural llisioiy were initiated in 1970. Authors shouldcontact the managing editor regarding style and submission procedures before manuscript submission. 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Individuals may purchase separate numbers from the Office of Publications, Muscimh oI Nalmal History, The LIniversily of Kansas, Lawrence, Kansas 6604.^-24.S4 I SA. f-'ninl Cover: ihc jour species oj Sieaiueriliicks asjollows: I pper lefi \\ liiieheiiiled I'll^^litlcss Sieanier- (liicks (I'hoto;^rapli h\ R Siraiiei ki: Cpper rii^hl — Moiielluiue I- li;^luless Steamer -iliieks iPlioloi^rapli h\ D. /.immenmin): Lower left — iatklaiul l-'lii;li!less Slcamer-dueks I Plioloi;riiph In- B ('. l.i\e:e\): unci Lower rii>lu — Llyliii; Stcamer-diiek (Photoiiraph by (!. L. Niieclilerlein). oc so in TtiK UNivi-;Rsin oi Kansas Museum oi- Naturai. History MoNOCK \I'H No. S 10 Docciiiher 1^)42 Taxonomy and Identification of Steamer-Ducks (Anatidae: Tachxercs) Bradley C. Livezey and Philip S. Humphrey Museum (if Natural llisioiy The ihiivcrsiix of Kansas LawiciHC. Kansas hM)45-2454 USA MUSEI'M OF Natlral Hisiorv Dyche Mali Thh UNi\r:RsiTV ni- K\nsas Lawri \i I . K \nsas MONOGRAPHS EJilor fur litis issue: RiLluird [•. Jolinsloii Mdiuiiiiiii; lulilar: Joseph "I'. Collins MCZ JUL 9 3 UNlVcI-SlTY Monogia|ih No. S Pp. i-l2.'i; 2y figures (2 in eolor); 13 tables: 1 appemiix Published 10 December 1992 * ISBN: 0-89338-042-3 © 1992 H\ Ml sci'M or NAruRAr HisroKi DVCHE Hali. Till-: University or Kansa.s Lawrenci;. Kansa.s 66045-2454, USA Primi i> m Usrvi Rsiiv oi Kansas Pkintini; Shrvick l.AWR[-N( I . Kansas contp:nts INTRODUCTION 1 ACKNOWLEDGMENTS 1 METHODOLOCilCAL NOTES 2 Specimens - Molls and Plumages 2 Measiiremenls 2 Slalistical Analyses 3 ORNITHOLOC.ICAL HISTORY OF THE STEAMER-DLICKS 3 Early Deseiiplions 3 Flighted and Flightless Species 4 A Second Flightless Species 1 1 A Fourth Species 12 Overview 14 SYSTEMATIC REVIEW 15 Relationships ol l\it. Iiwres 15 Synonomies lor lac hycres 16 Genus Tcuiiycirs 18 Flying Steamer- Duck tTachyercs piitachoniciis) 20 Falkland Flightless Steamer-Duck iT(i< hvcirs Ivuchyplcins) 27 Magellanic Flightless Steamer- Duck iTdclncifs piciicrcs) 30 White-headed Flightless Steamer-Duck iTik Incnw Icucm cpluiliis) 35 MOLTS AND PLUMAGES 36 History of Study 36 Comments on Descriptions 46 Ten llVCIVS pilhll hdiiicus 48 Tachycrc.s hnuiiyplcnis 54 Tacky crvs picncrcs 56 Tachycics Icmoccphalus 59 DIAGNOSTIC CHARACTERS 63 Generic Characters 63 Detennination of Age 65 Qualitative Characters of Species 67 Quantitative Characters of Species 75 KEYS TO IDENTIFICATION OF SPECIMENS 90 Skins 90 Skeletons 91 FIELD IDENTIFICATION 92 Introductory Comments 92 Ecological Segregation 92 General Appearance 93 Behavior 93 Vocalizations 94 STEAMER-DLiCKS IN CAPTIVITY 95 PROSPECTS FOR THE FUTURE 97 SUMMARY 98 RESUMEN 99 SPECIMENS EXAMINED 101 LITERATURE CITED 105 APPENDIX 121 INTRODl'CTION Durmy our leii-scar stLkl\ ol the sieaiiicr-diiLks {Tcichycrc.s ). a moderately speeiali/ed Soulli Aiiici i- can genus of shelducks (Tadorninae: IJve/es 1986a). our piiniar\ inierests have lieen llie mor- phological bases and adapli\e signiticanee ol tlighllessness. geographic variation, sexual diiiioi- |ihisni, and phylogenetic relationships ol the loui species. ,-\s these investigations progressed, hovv- e\ei-. :t became apparent that basic taxoiiomic issues, including alpha-ta\ononi\ and the ilesig- nation of types, and the data and techniques asso- ciated with identihcation of specimens, required attention. Taxonomic difficulties ha\e |ilagued the study of steamer-ducks since their discovery in the late sixteenth centur\. and certain of the present- tla\ problems in s\steniatics of the genus ha\e their origins in this history of controversy. This state of affairs is in part due to the three most salient characteristics of the genus Tacliycrcs: { 1 ) large si/e. which exacerbated the difficulties o\ collection and study of specimens; ( 2 ) widespread flightlessness. an often conspicuous characteristic thai principally created taxonomic conlusitm; and [?i) drab gray-and-white plumage, which offered fev\ clues to the recognition and diagnosis ol species. The taxonomy ofTiichyens also has been prone toinersmiplilicalion ("lumping ol s|iecies'"). ap|iarentl\ because of the traditional view that s|iecies of waterfowl should be reatlily distin- guishable using plumage characters, even under held conditions. Ihe present pa|iei has six major objectives: ( I ) to present a history of the study of the genus. v\liich in turn will provide an insight into the complicated taxonomy that has been applied to its members; (2) to provide generic aiul specific syn- onviifies and species accounts; (.^i tii present the a\ailable information on the molts and plumages of 7(/(7;\'('/(',s: (4) to cimipare the diagnostic char- acters of the four species and to construct keys to the identification of specimens; (."i) to summari/e information on field identification aiul asiculture of steamer-ducks; and lb) to present a subject- indexed bibliography of the considerable but scat- tered literatLire on steamer-ducks. Our hope is that the work will enable ornithologists, some of whom have shared with us their concerns, to identify steamer-ducks in the haiul anil (uinler giiod condi- tions) in the field. Should this endeavor prove successful, we anticipate that these unique birds will receive the continuing siiidv that they de- serve. ACKNOWLEDGMENTS Our research on steamer-ducks was supported during 1980-85 by National Science Foundation grants DEB-8()-1240.\DEB-8 1-1 7942. and BSR- 83-199{)(). the Kansas University Endowment Association. Southwestern College, the British Broadcasting Corporation. W. Saul, M. C. Thomp son. L. A. Osborne. R. T. Peterson. T. Mastm. K. Hamilton, and the Humphrey family. Livezey also was supported in part by NSF grant BSR-85 I6b2.v Collecting permits were issued by E. O. Gonzalez Ruiz (Direccion Nacional de Fauna Sylvestre. Argentina). L. O. Saigg de Chiaha (Proteccion Ambiental. Chubut. .Argentina). D. H. Soria (Ganaderia. Santa Cruz. Argentina). E. Cruz (Servicio Agricola y Ganadero. Chile), and Sir R. Hunt (Civil Commissioner. Falkland islands ). Field work in Argentine national parks was made pos- sible by .\. Tarak (Direccion Nacional de Parques NaciiMiales). Logistic support was provided by J. M. Gallardo. R. A. Bockel. and .1. Navas (Museo Argentino de Ciencias Naturales. Argentina). G. PincheiraandT. G. Iriarte (Universidad de Chile), and M. M. L'Huillier. D. Bersalobec. S. Canessa. C. Montenar, and D. Nunez D. (instituto Profes- sional de Osorno. Chile). Essential arrangements were made by G. A. Giaroli. F. Liibhe and F. Villar. Housing and laboratory facilities were arranged by O. Kuhnemann, D. Nunez D.. P. Medina, and J. Sesti; B. Mayer and F. V. T. .1. Fauring provided a home and field support at Puerto Melo. Logistic help and friendship were provided in the Falkland Islands by A. F. G. Douse (Stanley ) and A. and Y. Davis (Lively Island). We also are grateful for the assistance and hospitalitv of B. Rosso. L. Orquera. E. Plana. G. Piacentino, J. E. Bonczak. R. E. Caferata. A. Fernandez. R. Landivar. G. C. Sarccda. F. Erize. R. Straneck. W. Conway. Y. Lucero. P. Canevari. M. A. E. Rumboll. R. Hall. H. Niemever. UNIV. KANSAS MUS. NAT. HIST. MONOGRAPH NO. S M. SallalxTiv A.. A. Veloso. J. Ballastcros C. and the (iihson I'amily. Spcciiiicns were made avail- able by tlio l-icld Museum of Natural History (Chieago). British Museum of Natural liistor\ (Tring). American Musemn of Natural llistor\ (New York). San Diego Museum of Natural His- tory, Peabody Museum of Natural Flistory (Yale University). Museum of Comparative Zoology (Harvard I'niversity ). Museum of Zoology (Llni- versity of Michigan), and U. S. National Museum of Natural History. R. Straneek (Laboratorio de Sonidos Naturales. Museo .Argentino de Ciencias Naturales. Buenos Aires) prin ided tield record- ings of vocalizations of steamer-ducks, and J. W. Hartiy (1-lorida State Museum. Gainesville) pre- pared sonograms of selected recordings. I'npub- lishetl observations of steamer-ducks inciirporated into the liistribution maps were pro\ ideti by P. C'anevari. J. C. Chebe/. X. Ferrer. O. Kiilinemann. T. Narosky. M. Nores. and R. Straneek. We also thank R. Mengei. M. Jenkinson. and their col- leagues ft)r preparation of speciinens; P. Rasmussen for executing Figure '->: and K. McManness, K. C'orbin. and M. Schmal/ for t\ ping. METHODOLOCilCAL N()TP:S Specimens Much of our work on steamer-ducks has been based on observations made and specimens col- lected during our Held v\(nk. We made five trips during 1979-84 (the first with Max C.Thompson), gained first-hand experience w iih all four species ofTachyeres. and for all but /'. Icticuicpluiliis we studied each at several localities. By species and locality, these were: T.palaclutiucus — Puerto Melo, Lago Fontana, and lagos Futalaufquen and Kriigger, Chubut, Argentina; Puerto Deseado, Lago Argentino. and lagos in Parque Nacional Perito Moreno. Santa Cru/. .Argentina: Ushuaia and Lapataia, Tierra del Fuego, Argentina: Bahia de Ancud, and nearby lagos Llanquihue and Rupanco, Region X. Chile: 7'. hravhypicrus — Lively islaiul and Port Stanley, [•'alklaiul Islands: I'. Icucocepluiliis — Puerlt) Mek), Chubut, Argentina; 7'. plcneres — Ushuaia and Lapataia, Tierra del Fuego. Argentina; and Bahia de .-Xncud. Chile. These specimens and associated data were aug- mented by specimens studied at other institutions, which contributed greall\ lo the localities rejire- sented. A complete listing of the specimens exam- ined is given in a later section. Moi IS \M) Pi I m\(;ks Description of plumage patterns useil the color scheme of Palmer (1962). Downy yoimg were assigneil to age classes using standard criteria tietaik'd ni llumphiey and l.i\e/e\ ( I')S.'i:')4.'S ). Measurements Masses were measured w ithin 1 2 hours of col- lection of the birds using spring scales. Most skin measurements used are standard (Baldwin ct al. I9.il). although a few comments are needed. Sample sizes for tail lengths are comparatively small because we collected this datum only in the latter half of the field work, and because of a relatively high frequency of specimens with worn or missing rectrices. Lamellar counts were the total number of lamellae (regardless of size) on one side of the upper bill of a fresh bird: counts in dried skins may not be reliable because of reduced visibility and shrinkage of lamellae. Wing areas were estimated b\ doubling the area (using planimeter) of the tracing of an extended wing. Skeletal measurements are largely self-ex- |ilanalory, but a fev\ warrant description. These include some of the skull measurements: cranial height m;L\imal distance from dorsal surface lo ventral surface of braincase: cranial length — distance along midline from frontonasal suture to posterior of braincase: postorbital w iilth — maxi- mal width of cranium, measured on the lateral processes of quadratojugal bones: antorbilal w itlth maximal distance across the antorbilal processes ol the laciymal bones: frontonasal width — dis- tance across lostrum at trontonasal suture: skel- etal height, length, and width ol bill — measured as on skin but base of bill delined as frontonasal suture. Head wiilth of the Innnerus is the maximal bicadlli of the element al ils proximal end. I lead STEAMER-DLIC-KS (ANATIDAE: TACHYERF.Si wkIiIi III ilic lemur is the uullh ot ilic pioxinuil L-iul will) lliL- lic.id 111 the bone oriented jierpen- diciil;irl\ to the ealiper surface. Tihiolarsiis leiiglh iiieludes that of cneinial crest. I, east widths at midpoints (LWMs) were measured on si\ major limb elements. Osteological iiomenelature follows Baumel ci III. ( 1^'?'-)) with alleiiiate icrminolotis of Howard ( 1424) given in parentheses. Statistical Analysks LInivariate comparisons were made using two- wax analysis of variance (ANOVA). E.xcept for masses, areas, and ratios, which were loy-trans- fornietl for anahsis. all statistics were based on rav\ data. Discriminant functions and canonical analyses were used to contrast species using suites of mea- surements (Pimentel 1474). Analyses were per- formed on raw data: analyses based on log-trans- formed (base (■) data produceil virtually identical results and affected no inleiences or interpreta- tions, (-or multivariate analyses ol skeletons, we used a program for estimation of data missing because of bilateral breakage or deformity: these estimates composed less than \'^''( of any data set analyzed. All programs used were part of the Biomedical Computer Programs (Dixon 14SS). ORNITHOLOGICAL HISTORY OF THE STEAMER-DUCKS EaRI ^ DkS( RIPTION.S In I .'iS2. Pedro Sarmiento de Gamboa observed an unfamiliar duck in the Straits of Magellan, which inspired the following description ( I X4.'i:.S3; translation o\ Sarmiento de Gamboa I 76S ): "in the water they cannot rise but by their feet, using their pini(Mis as oars. They thus go through the water w ith great velocity, and they leave a track like that of a boat when propelled by oars. Their velocity is so great that a good boat under sail, with a fair wind, cannot overtake them." Eighteen years later in the Straits. O. Van Noort (1426:4S) noted as common a flightless "goose" in Goose Bay. Dur- ing passage of Captain Wood through the Straits in 1664. Hacke {1644:60) observed "...great Blue- Dticks. which are not very shy." ,\ number of subsequent voyagers to the Straits and the l-'alklaiul Islands wrote of these large wa- terfowl and their characteristic, spray-prodticing method of surface locomotion, most referring to them as "race-horses" or "loggerheads" (Pernety 1764:370: Byron 177,^:50: Hawkesworth 1773:41 1-f 1 2: Penrose 1 775:3.*S: Clayton 1774:40. 1776:104: Cook I777:IS6. I77S:27: Elliott and Pickersgill 1 4X4:34). Whether the name "logger- head" w as based on the phy sical appearance of the birds or their pugnacious behavior is not clear. Byron ( I773:.^0-.^I ) described them as "...a bird much lariier than a eoose. which we called the racehorse, from the velocity with which it moved upon the surface of the water, in a sort of half Hying, half running motion." Most early accounts were distinctly culinary in perspective. Penrose ( 177.S:3.'>-36) wrote: "One kind of duck however we had. which was by no means a delicacy: we called it the loggerhead, for an obvious reason: and it seemed to be a large species of the Muscovy \Cciiiiihi mosclhitci] sort, only its w ings resembled those of the penguin: as these ducks. ..were utterly tillable to fly. our method was to drive a large team of them together into some delile. and then to knock down as many as we had occasion for. The use we put their flesh to was to boil it well in the copper, and then to give it to our pigs... .and though this mode of fattening may appear rather intleli- cate to some people, yet it is astonishing how the hogs thrived with it." Clayton ( 1776: 104) reported similar exploits: "But here is a species of ducks, called the loggerhead, from its large head. They have short wings, are unable to lly. anil only swim and flap along on the water at an extraordinary rate. When driven ashore w ith boats ihey run fast, but soon squat down and are easily caught: they are eatable, but are but indifferent food: thev are of a dark brown dirty colour." Cook ( 1777: 1 N6) also described the locomotor behavior of the birds: "Here is a kind of duck, called by otir people race- horses, on account of the great swiftness with which lhe\ run on the water: for thev cmnot 11 v. UNIV. KANSAS MUS. NAT. HIST. MONOGRAPH NO. 8 ihc w ingsbciiiu loushDil losiipporl the botis in iIk- air." C(Hii<, evidently wiilunn the benclil ol' per- sonal e.xperience. was less critical ot'tiie palatabil- ity of the ducks, writing (p. 205): "We shot some I race-horses I . anti lound them to weigh twenty- nine or thirty pounds; liiose who eat ot ihem saiti they were very good." Molina (1782:239) may have relcrred lo this duck (known locally as the "quethu ") trom C'iiiloe Island (Chile). Murphy ( 19.^6) justihably doubled the relevance ot'the binomial name used by Molina (Dionu'dca chilocusis). one based on an inad- equate description and suggesting a relationship with tile lubenoses (Procellariiformes). Tlie au- thors of two of the earliest global faunal compila- tions referreil to the bird only by the vernaculai' names used by voyaging naturalists (Latham 1 785:43'): Buffon 1 798: 1 59). Beginning with nam- ing of the "loggerhead" nsAiuis ciiicrca by dmelin (1788:506). a species name later rejected as lui- available by Murphy ( 1936). the species, as then construed, was given six tlilTerent binomial names before its monotypy was questioned, l.alham (1790:834) applied the lirsi species name to be found available by later taxonomists — Aiuis hi\u InjUcra. King ( 1828:100) initially named specimens of the group as OiJcniia jHihichonica. describing the birds as forty inches long, jiredominantly gray with white specula and abdomens, having yellovs - orange bills with black nails, yellow legs, anil wings with a blunt spur at the bend. King( 183 1:15) later distinguished anoihei' species. Mkioptvi iis paiachouiciis. that was more red-colored on the throat and scapulars, had a greenish-black bill, ami was smaller than its congener M. hru( lixpicid \sit\. evidently releiring to .\;;(/,v hrocliypicid Latham (1790:834). mentioned by Quoy and Gaimard ( 1824:347). King ( 1839:36) was not en- thusiastic about their jialatability. wiiting: "Ihe flavor of their llesh is so strong and tish\. thai at lirst we killed ihem soleU lor specimens. \\w or six months, howeser. on salt provisions taught many to think such fooil palatable, anil the seamen never lost an opporiunii\ of eating iheni. I ha\c preferred these ducks to salt beef, as a piescnii\e against scurvy rather than from liking theii lasie. ' Kins: ( 1839:542) also clantied the taxononnc dis- tinction, listing Oidcmui patculumicci as a syn- onym for flightless Mitroptcrns hiachyptcnis. and added to his description of the smaller species i.M. pdnic/iniiiiiis) its abilit\ to th. Ihe reapplication of the wdmc pdiacliniiic IIS to the tw o species recog- ni/ed by King, an action with important nomen- clatiual implications (Live/ey 1989b). evidently stemmed iVom his partiality to a name appropriate lor a bird "Patagonian in stature. ..as well as in station..." (King 1828:100). This taxonomic deci- sion marked the beginning of a century-long orni- thological controversy concerning the existence of both Hying and flightless species of steamer- duck, so named by King (1839:35) because of their resemblance to paddle-wheel steamships w hen "steaming" across the water surface. FiJCHTKI) AND Fl.KJH ILKSS Si'KCIKS During the period from 1830 to 1861. must naturalists, some familiar with steamer-ducks in the lield, mentioned only the flightless taxon in their works ( Darwin 1 839a: 1 90, 1 839b:257; Gray |S40:74. 1849:623: Forster 1844:338: Gray 1S44:14(); Gould 1841:136. 1859:96: .Strickland 1841:.39: Hartlaub 1846:19: Des Murs 1847:457: Lichtenstein 1854:100: Boeck 1855:511: Bonaparte 1 856:65 1; Germain 1860:315; .Selater 1860:389. lS61a:367). Eyton (1838:144) listed both species, but stated, without reference: "Both aie destitiUe of the |iowers of flight, merely using their w ings to flapper over the surface of the sea." I le also admitted to having "considerable doubts" as to the validity of recognizing two species. I^ar- win { l839a:257-258) observed steamer-ducks in the I'alklaiiil Islands ikuing his \oyage on the 'Beagle' and wrote: "In these islands a great loggerheaded duck or goose (,\/((/.v hnnliyptcia). which sometimes weighs twent\-two pounds, is \erN abundant. Ihese birds were in lormer ila\s called, from their extraordinar\ manner of pad- dling anil s|ilashing upon the water, race-horses: but now the\ are named, much more appropriately, steamers. Their wings are too small and weak to .illow ol flight, but b> their aid. parll\ swimming and parti) flapping the surface of the water, they move very quickls'. The manner is something like that b\ which the common house-iluck escajies STEAMHK-DliCKS (ANATIDAE: TMHYERES) 5 vvlien pursued h\ a ddg; bill I am iK-arlN sure lliat iX7lh:44-y3; lS71c:262) posiulaled lluil iheie the steamer nun es its w ings alleinalel\, msiead (il was only line speeies ol sicanier-iluek, aiul lliat botli loszether. as in other biixls. I'liese cliunsy. tlyiiit; individuals vveie but adolesceiils that with louueiheaded ducks make such a noise and s|ilash- maluril> would become too heavy for tliylit. iiiL;. that the elTect is exceedmgh curious. ...The Cunningham baseil this conclusion on the lelalive steamer is able to dive only to a very short dis- ossilication ot eight specimens: two partial skel- tance. It feeds entirely on shell-fish Ironi the kelp etons and two crania of '"adult" (presumably aiul tidal rocks; hence the beak aiul head, for the llightlcss) intli\ uluals; two skeletons of "imnia- purpose of breaking them, are surprisingly heavy ttire" flying birds; and two crania of unfledged and strong: the head is so strong |see Fig. I | that I young. He noted that his specimens of "adult" have scarcely been able \o fracture it with m\ birds were gray with orange-vellow bills, whereas geological hammer; and all our sportsmen soon "younger" birds (his /)i//(((7/()/(;(/(.sMvere smaller, discovered how tenacious these birds were of life." more red-colored on the throat and scapulars, and Two decades later, in 77;c Orr^i/i crall 1 906:40 1 : Reed 1907: 103: Cobb 1910:66: Beck 191 S:S|. The one- species view was solidified subsianlially by the endorsenienl given il by Owen ( I K7.'i:2.'S4. 266) in his replacement of the (nionolypic) generic name Miiroplcnis (erected by Lesson 1S2S:416) with the currentlv used Tacliycrcs (from the Greek. Taxviilpil^ meaning "swift rower"), because of the previous application of Micmpieriis to the North American freshwater basses. This change of genus was adopted by Sharpe (1899a). Although Owen ( 1 S7.'i:2.'i4) used the binomial ta.xon Tcnljycrc\ hriniiypU'iiiy in erecting the genus, most taxonomistsof the "one-species" school from 1876 until the early 19()()"s instead used the name Tacliycrcs cliwrciis to refer lo the group. Despite widespread acceptance during this pe- riod of the view that there was but one species of sieamer-duck. held observers, convinced of the existence of both flying and flightless species, published their views with increasing frequency. Giglioli ( 187.^:9.^4) was |iersuaded thai two spe- cies existed, and even suggested another, but con- tradictory, binomial name for the flying form — Micrtiptcnis iiiucrupicnis. Coppinger (1883:61- 62) observed flying steamer-ducks mostly on fresh- water lakes and flightless birtls on saltwater, and noted that color of plumage and bill distinguished young flightless birds from the flying form, in opposition to the model presented by Cunningham. Although not discussed in the literaliue. two poorly ossitied skeletons of juvenile flightless steamer- ducks, which alone could have disproveti the de- velopment-related hypothesis of flightlessness. were collected in 1888 on the ""Albatross Hxpedi- tion" and deposited in the LI. S. National Museum of Natural History. Ousialet (1891:8212-2.^2), prompted by held observations and specimens collected near Cape Horn, including osteological comparisons, rel uteil the view of Cunningham and treated the Hying mu\ flightless forms as distinct species, tievoting six teen pages to the description of the former: Oustalei includeti. however, several mediiuii-si/ed. rela- tively short -winged birds from the l-alklamls in his M. pahichoiiiciis (see table on p. 2 I ."^ i. In addnion to arizuments based on analoinical differences. disiribulions. and locomotion. Ousialet (pp. 2 1 .V 214) pointed out that the frequent association of the two forms in flocks is not rele\anl to the question of their possible conspeciticily. .Several museum taxonomisis and anatomisis also showed less than complete acceptance of the theory ol Cunningham. In an exhaustive synonymy of the genus. Salvadori (189.^:37.^) recognized only one species ( Tacliyeres cincrciis ) but acknowl- edged the observation of Cox ( I86.^:2.^.'S) of nu- merous flying Mi( niprcriis cincrciis on the .Andean lakes. Schalow ( 1 898:672-674) reviewed the taxo- nomic debate and considered the plumage charac- ters given by Oustalet ( 1 89 1 ) Ui be inadequate for diagnosis; like Salvadori (189.S). .Schalow listed only T. cincrciis. Beddard (1898:4.^7). although evidently accepting the basic thesis of Cunningham, found no greater density of bone in flightless steamer-ducks than in other vvatertovvl. Newton ( 1893) stopped short of complete endorsenienl of the theory proposed by Cunningham, and he Il893:.'i97) even suggested the unprecedented notion that the flightlessness of Taclncrcs was relatetl to the molt of the remiges. After the turn of the centur\. the controversy became more pointed. Dabbene ( l'->()2:403) con- sidered the one-species hypothesis iif Cunningham ( 1871a), but rejected it based on the discover) of a fully ossified steamer-duck specimen that dif- fered anatomically from flightless birds and "'cor- responded perfectly"" with the flying Micropicrus patdihoniciis describeil by Ousialet (IS*-)!). Dabbene ( 19()2:4()4-4().^) went so far as to con- sider the fl\ ing and flightless forms to be generi- callv disiinci — Micrnpicnis pniciis and Tacliycrcs cincrcits. respectivelv. Crawshay (1907:110-115) treated living and flightless steamer-ducks of Tierra del Fuego as a single species (Tacliycrcs cincrciis). concluding that (pp. 110-111): ""The question of whether one or two s|iecies are to be admitted has been final Iv delermiiicd in lav our of one in the opinion of the majorilv....! do not think I came across one I sheepman I whohaddefinitelv aniveil al iheknowl- eilge that the powerof flight could be possessed by some individuals ami lacking in others."" Nicoll I l')l)8: 17 1-172) sLipportctl the view .ulvancetl bv Ciiiinini.'ham. olleiiiii: ihe follow Iiil; ralionales: STEAMER-DUCKS (ANATIDAE: lACHYERES) "All the examples we obtaiiiccl. ami all those I ha\e examined in Ihe British Miiseiini. iimloiibt- edly belling to one speeies onh: and it I nia\ ventine to give an opinion. I should say that Pio- I'essor Cinininghani's is iiiuioiibiedlx the right so- Uitiiin. as it would surel_\ be an almost un|iree- edented thing to tind two very nearly allieii s|iec'ies living together, one able to fly and the other unable to do so. At the same time, it is somewhat remark- able that, although we saw examples of this duek of all ages and mall stages of deselopment. we met with but one w hich was able to fly. It may be that this species is gradually becoming entirely flightless, and that the \ olant indi\ iduals met w ith are sur\ ivals of a former stage in a stale of transi- tion, and have not as yet lost the full power of flight." Paessler (14(W:|{)3) also believed that steamer-ducks comprised a single species, although he had seen some individuals fly for .'iOO-IOOd meters w hen pursued. Scott and Shaipe ( I *■) 1 2:4M2 ). after an examination of specimens of steamer- ducks in the British Museum and Ihe Museum of the Jardin des Plantes. including those identitied by Oustalet (l\ Mr, Phillip's collector has only been lo the Falkland Islaiuls, which are a siionghold of Tachycrcs luiuicliniiicus.... "That Mr, Brooks has not seen /. jnitiU lioniais fly and could not make them lis although he has seen "thousands." notwithstanding thai those birds were, judging I'rom his descriiition. really / paliK li(>iii( lis. oiilv lends lo |iro\ e thai Mr. Brooks has either exceptionally bad luck or was not able to identif) those birds when seen on the wing," Evidently, it occurred to neither lilaauw nor Phillips that a population of flightless, sexually dichromatic steamer-ducks similar in aspect to /'. Piihiclioiiiciis inhabited the Falklands. Mogensen ( I917:84-S.'^). indcpeiulentlv of Blaauw. was convinced that two anatomically dis- linguishable species of steamer-ducks occurred on ihe continent. He noted that both sexes of the flightless species have grey heads and yellow- orange bills; w hereas in the flying species only the male is so colored, the female being darker in the head and bill. Mogensen also observed that the flightless species is limited to sea coasts, but Ihe flying species can occur in both fresh and salt w ater. and in the latter both species often occurred logether. He even provided measurements to dem- onstrate that the wings e)f flying T. pnuiclwnicus were longer (.^4-36 cm) than those of heavier, flightless T. ciiicrciis (26-28 cm). Qualihed support for the two-species view also was forthcoming from observers in the Falkland Islands, Wace ( 1921:201 ) reviewed the literature on the controversy and. although he went so far as to neat the flying form as a taxonomic variety paiiiclioniciis of the single species T. ciiicrcii.s. he concluded by reviving the idea that flying birds are the lighter-bodied adolescents ol Ihe flightless species, Vallentin ( 1924:322-328) concluded that (p, 324): "According to my observations there are two species of Microplerus lo be lounil in ihe I alklamls, and those accurate observers. Captains King and .Abbott, were absolutely correct in their brief diagnoses," Vallentin ( 1924)expliciil> listed onl_\ y , rincrciis for the Falklands (p, 322). as in his previous works (Vallentin 1901:3.'i(): 1904:33): however, he referred (p, 32.^) to "the "Flying Log- gerhead". .U. piitdcluiuicus (King)" in the text, reported having flushed several flying steamer- thicks from nests located well inland, and noted ihai lhe\ had proportionately longer wings and more oval eggs than the flightless form, 1 he situation in the Falkland Islands was clari- lied significantly by the observations ol' Bennett ( 1924. 19261. although evidenlh his contribution largelv was ignored hv sLibscqiieni woikers, Bennell ( 1924:2S()-2S2 ) provided mensural com- STEAMF.R-DICKS lANATIDAH: lACHYIiRLS) |i.u"isons lit ilic common "logger-lieail" ( 7, i uicrciis i and llic "Lainas-back duck'" {T. piiUii linnicus). including total length, wing length, four dimen- sions ol the bill, wing-spread, and lengths of tarsus and nntklle digit. He also noted interspecific dil- ferences in bill lamellae, bill shape, wing-spurs, coloration of primaries, sternal shape, si/e of su- praorbital glaiul. intestinal color, si/e ot testicles, and habitat. However, Bennett ( l'-)26:.^27) cau- tioned that, despite these distinctions, the plumage pattern of the Ihing species is almost identical to that of its tlightless relative. Phillips (IM2,S:287-2*^7). in his classic lour- N'olume work .1 Ndtuidl Histmy aj the Dm ks. had become much less certain of his laxonomic con- clusions on steamer-ducks. He stated in llic lirsi paragraph of his tiescription (p. 2S7 ). "I regaril ihc question of two races as yet unresolved but think we may go so far as to say that the hndings cannot all be explained on the basis ol one natural spe- cies." He still retained Tachycrcs ciiicrciis as the single species in the group, but repeatedly admit- ted in the text that more than one species might be recogni/ed. in hisdiagnoses Phillipscompromised by separately describing a ""gra> phase. Tcicltxcrcs rincirits'.'" (p. 2S7) which correspondetl to the Patagonian tlightless form discussed by Blaauw (1916, 1917): a "red phase. Tin hxctcs puiiu hun- iciis?" (p. 2SS) which agreed v\ith the tlying form of Blaauw and others: and an ""intermediate t\ pe" (p. 2SM) comprising the large, possibly tlightless birds from the Falkland Islands, described by Brooks ( 1917) and Phillips ( 191 7). that resembles in plumage and soft parts the tlying birds of the continent. He pro\isKinall\ concliKled that these "phases" represented age-classes, which presumed that sieamer-diicks require up to three years to reach matiirilN'. Phillips (pp. 290-291) acknowl- edged several problems with this treatment: (1) there were known to exist large tlightless steamer- ducks (on the continent) in which both sexes ha\e yellov\ bills, the \oung of which being flightless trom birth, but that have wings that are absolutely (not relativel\ ) shorter than those of the smaller, ""red" tlying form: (2) some ""red-type" birds were known to be reproductively mature, and appeared to be lulls developed in plumage anil wing spurs: {?< ) apparent abundanceof ll\ ing birds \ arieil inex- plicabl\ even m the same localit\. e.g.. R. M. Beck tinind at Chiloe Island that tlying birtis were com- mon during May-Jinie but, during December-Feb- ruar\. W. Percy did not see a single steamer-tluck ll\. even when pursued: (4) in the 1-alklands it appeared that males of the large "gray-type" mate w ith ""red-type" females, but the young produced from such parents were unknown. The apparent mixing of "types" and diagnostic characters in the Falklands seems to have been primarily respon- sible for the reluctance of Phillips to elevate his gra\ and red '"phases" to full species. Pliillips ( 192.^1) was not alone in his i|uandary. Snouckaert van Schauberg ( 1926: l."i()-l .S 1 ) re- viewed the differing views about the genus, but olTered no opinion of his own. Wetmore ( 1 926:4 1 S ) listed only one species. T. vincirns. but com- mented: ""The question of specific entity among the flying and non-llying steamer ducks is one that IS tar from settlement." .Stresemann ( 1927:47) re- V ievved briefly the controversy, and concluded by quoting a letter from Phillips (dated 14 December 1926) that "...the presence of one species will not explain the story of the steamer duck." Stenhouse ( 1929: IS."!- 1 86). in a catalog of several of the Hrst specimens of steamer-ducks stored at the Scottish Museum, acknowledged the taxonomic debate, but judged that (p. 186). ""The balance of opinion, especially among held naturalists, is in tavour of there being two | species j."" Mogensen ( 19.^0:207), however, adopted a weaker position, relegating living pdiacluiiiicus to a subspecies of a single species T. ciiiereus. in his Clwcklisi oj Buds ofrhc World. Peters (19.i 1:176) listed only a single spe- cies of steamer-duck. T. hviichxpicnis. but foot- noted that the question concerning the number of species to recognize in the genus was ""...still an open one." Conversely, Hellmayri 19.i2:.^.^.^-.^.^7) described both 7'. hrachyplcriis i.\rn\ T.palavhonuiis for Chile, but sinnlarly stated (p. .^^7) that ""...the question whether the II v ing iiuliv iduals reallv con- stitute a different species is tar trom being settled." Reynolds ( i9.^2:.^.'i) went further, stating: ""it is quite incomprehensible to me thai the huge series ot skins in the .States has not established definitely the fact that in Tierra del Ftiego — at all events — two species must be acknowledged." Dabbene I U),^2) reviewed the |iublished controversy con- 10 UNIV. KANSAS MUS. NAT HIM MONOGRAPH NO. 8 ccrniiii: ilic s\sicm;itKs cil Tiiclivcrcs. including tiic lliive "phasL's" discussed h> l^iiiiiiiis (192.'^). and prov iiicii accoiinls I'oriwo species — tlightless 7'. cincrcKS ami IligiUed I', paluchonivus. Casares ( 19.^.^: 14(1) tallietl t\u) species olsieanier-ducl\ fur .Argentina linciiuiing llie Falklands). j-iiii listed no binomina or distrihulional limits. At this late tiate. a curious, almost l.amarckian variant ol the "adolescence' hypothesis ot Cunningham was proposed by Chapman ( iy2fi:l2(); iy3-^:.^6l-.Vi2). a natmalist with sub- stantial lield experience with both Hying and flightless steamer-ducks on the coasts and moun- tain lakes of southern Chile. Chapm.m obsersed that flying indivitluals occurreil on the coast in winter but evitlently not in summer, when they were seen on inlaiul lakes, and flightless birds occurred year-round on the sea coasts, accompa- nied by obviously young birds in summer. He allempted to reconcile this apparent seasonality of tlightlessness by suggesting thai there was only one species of steamer-tluck in which all yining birds (until their first winter) could lly. but that birds nesting on saltwater later became flightless, whereas birds nesting on freshwater must travel betvseen their nests anil coastal feeding grounds and hence retained the power of flight throughout life. Palmer (19.^4) also cited the 'adolescence" hyothesis as the explanation for flighted and flightless steamer-ducks. h'inally Lowe( 1934:467— W.'Sj.armeil v\ithsiinl\ skins, eggs, embryos, ami tietailed field notes on both flying and flightless steamer-ducks collectetl by I'. W. Reynolds in Tierra ilel I-iiego. as well as single spirit specimens of both the Hying (from Reynolds in Tiena del Fuego) ami flightless forms (fromW. Percy at Chiloe),csiablished bey omi doubt the existence of both flying ('/'. pdiuchonicus) and flightless (■/'. /jrcuiiyplcrns) species of steamer-duck in continental .South .America. Lowe and Resnokis ilocumentetl a number of tliffeiences: hafiital amf locomotion; plumage pattern and soff parts; tracheal ami s\ ringeal morphology ; egg si/e and thickness of shells; weights, tlimcnsions, muscle weights, and plumage pattern of well-tle\eloped embryos; and dimensions of cranial and postcranial skeletons. They even listetl the ihlferent names given the two species by the local ^'ahgan and ( )iia tribes. Re\ nolds and Lowe lackeil specimens from the lalkland Is- lands, but Reynokls (/// Lowe 1934:470) as.serted: "In the lalklami Islands the case, if not identical, is similar; possibly the forms found there may require subspecihc separation from the corresponding cat- egories of Tierra del Liiego. I have heard this belief expressed, and Mr. Bennett's remarks (Ibis. 1926. p. 327) do not altogether fit my Tierra del Fuego specimens." Lowe (1934) also specifically aiklressed the hy|iothesis of tiev clopmental loss of flight pro- posed by Cunningham. Based on an examination of skeletal specimens then available, he wrote (p. 4SS-489): "...At this distance of time we may. too, have little or no hesitation in stressing the opinion that Cunningham hati a v cry inailequate idea of the complexity of the |iroblem v\hich lay before him. We may. loo, feel confulent that the birds he col- lected with their cranial sutures still unfused were luvenile specimens, which mav well have be- longed to either the flying or non-flying species. Be this as it may. however, there does not seem to be a scrap of ev idence for Cunningluim's theory that the fly ing Sleamer Ducks are only the Juve- niles of the non-flying. The osteological speci- mens collected by Mr. Rev nolds. as well as those in the British Museum, so far as one can place reliance on them. disprove it." With this statement. Lowe finallv laid to rest the hvpothesis of Cunningham, altfiough the idea remained in the popular literature for decades (e.g., Neilson cl al. 19(10:2466). Not surprisingly. Reynolds ( I934:3.'i()-3.'il; l93.S:S4-S.'i) promptly employed Lowe's new tax- onomy in hisow n works. However. Percy ( 19.34:867- S6S). having |irov ideil Lowe wiih the important spirit specimen of the (conlinental) flightless fonii. was not enthusiastic about scime of Lowe's conclu- sions. Percy (1934:867) denied having statetl any- where (as averred by Lowe | I934:46S|) thai he was com inced ol the v alidity of the "one-species' view, but then went on to point out ""undoubted facts" on steamer-ducks w hich he felt vv ere m)i considered by Lowe( 19341. Ihese points were: ( I ) flying birds are absent from the coast of central Chile during De- cember-February when downy young are present: ami (2) during May ami .lune tfie ""same flock" contains a mixture of flving. Ilightless, ami "inter- STEAMER-Dl CKS (ANATIDAE: IACHYI:RI:S) iiicdialc" slcanioi-dLicks. coiilrais lo ihc claim ol Lo\\c( l'-)34:46cality as T. paiaclidimiis. Three skiii specimens col Iccted by C. Kovacs — a male from Piinta Tombo (Chubut) on 19 April 1968 and a male and female from Camarones on 10 July 1970 — were origi- nally idenlihed as 7. prcncrcs and arc held at the Museum of Natural Science. Louisiana State Uni- versity. C. Kovacs also collected and prepared as skins two male steamer-ducks (now at the Museo Argentino de Ciencias Naturales. Buenos Aires). collected on 16 November 1971 and 5 February 1972 in the Bahi'a de Camarones. Chubut: these were identihed as T. pataclhuucus. In November 197 1 . M. Gochfeld collected a male steamer-duck found dead on the beach at Punta Tombo which was prepared as a skeleton and identified as / ptcncri's (now at .^merican Museum of Natural History. New York). On 10 June 1972. C. Kovacs collected another pair of steamer-ducks at Camarones. Chubut. which were donated as mounted specimens to the Museo Argentino: the specimens remained uncatalogued and unidenti- fied until 1989. On 25 August 1972. J. R. Jehl. Jr. collected one male and one female steamer-duck in Bahia Concepcion. Chubut: the male was pre- pared as a study skin and the female as a skeleton ( both deposited at the San Diego Museum of Natu- ral llistor\ ) and both initially were labeled as T. piciicrc.s. then re-identified as 7". patiichnniciis. Boswall and Prytherch (I972:l2.-i) found steamer-ducks nesting at Punta Tombo. Chubut. which they initially identified as T. ptcncrcs be- cause of the apparent fiightlessness of the birds. Later the\ were persuaded by Olrog (based on presumed breeding ranges) and J. Delacour and P. Scott (from their examination of a photograph of three birds i that the species involved was 7'. puicK liiiiiuits. Boswall and his colleagues only savs a biril "'tl\ ' once in live da\s of observation, and this was a very short, weak, downhill passage of a female from nest to water. Evident fiightlessness of the birds was attributed lo wing- molt, which seemed to be indicated in the photo- graphed birds (p. 78). a condition confirmed later by M. \V. Weller and O. S. Pettingill (Boswall 1 973a:35). Boswall (197.^a:35) stated that the wing length of a drake found dead also supported the identification. Boswall (I973a:33) and Boswall and Maclver ( 1979:75) also reported the measure- ments and weights of six eggs from a nest at Punta Tombo. which were larger than measurements for [\ pahuhiiniciis presented b\ Murphy (1936:969) and agreed most closely with those for T. hruclnpienis. Boswall and Maclver (1979:75) speculated that the small means given by Murphy ( 1 936 ) for T. palachimicus may have resulted from misidentifications of large 7'. /'(//(/( In in mis eggs as those of 7\ hrachyplcnis. Similarly. Daciuk ( 1976:27-29. 1977:363) identified by locality the steamer-ducks nesting on Isla Quintano. Golfo San Jorge, Chubut as 7'. patch hoiiicus. despite the apparent fiightlessness of the birds and their un- usually large eggs. Todd ( 1979:160) reported the suspicion of M. Rumboll. an Argentine ornithologist, that flightless steamer-ducks on the Atlantic coast of Argentina were either T. hvacbyptcnis. or an undescribed species or subspecies. Rumboll and F. Erize per- suaded P. S. Humphrey and M. C. Thompson to collect specimens of the steamer-ducks in coastal Chubut during an expedition to Patagonia in 1979. Based on these specimens, collected from Puerto Melo (Chubut). Puerto Deseado (Santa Cruz), and Llshuaia(Tierradel Fuegoi.as well as skins exam- ined in Argentine museums. Humphrey and Thomp- son ( 1980) provisionally recognized (but did not formally describe) four new species of steamer- tluck: ""white-headed steamer duck. "" flightless, of coastal Chubut: "'masked steamer duck." also flightless and from coastal Chubut: "lesser Hying steamer duck" of southern coastal Patagonia: and ■"pygmy flying steamer duck." based on a single skin specimen froni Lago San Martin ( Santa Cruz I. Additional specimens collected by Humphrey and B. C. Livezey in marine and freshwater localities during the next two years permitted a formal de- 14 UNIV. KANSAS MUS. NAT. HIST. MONOGRAPH NO. 8 sLTipticni ot llic VVhiiL'-licadctl l-'lightlcss .Slcaincr- Duck (7. leucoccpliulus: Humphrey and Thomp- son 1981). Upon .sub.sequent examination, the specimen.s collected earlier in Cluibut by Young, Humphrey, Kovacs, Gochfeld. and Jehl also proved to be /'. leucoccphalus. Humphrey, howe\cr. did not describe the other three putati\e laxa. The "masked" torm was found to be a collection of small individuals ol' T. leucocephalus in alternate plumage. A larger sample of flying steamer ducks revealed that the "lesser" form was an artificial collection of small specimens from the osteologi- cally variable and geographically differentiated T. patachoniciis (Humphrey and Livezey iy82a, Livezey 1986b). The single specimen of the "pygmy" form was determined to be a juvenile of freshwater-nesting T. piitiicluuiii us. OVKRVIF.W Throughout the taxonomic history of steamer- ducks, there were repealed, protracted, and often imaginative attempts to reconcile contemporary view s with new. distinctly contradictory informa- tion. There also w as a stubborn reluctance to admit the existence of two closely related sympatric species of duck that appeared to ditfer |irmcipally in the ability to fly. Indeed, ornithologists for several decades preferred the improbable notion advanced by Cunningham that flight in steamer- ducks was a function of immaturity, a conclusion based on a small, unfortunate sample in which the flightless species (7". piciicrcs) was represented by adult specimens and the flying species by incom- pletely ossified juveniles or subadults. The tax- onomy proposed by Murphy (19.^6) had a pro- loimd influence on subsequent workers who en- deavored to make their observations and interpre- tations conform to his scheme. Taxonomic progress undoubtedly was impeded also by the overall simi- larity in size and appearance of the species, a problem exacerbated by the occurrence of three molts and plumages per annual cycle in some or all of the species ofTcicliycrcs (Humphrey and Live/ey i982a). Difficulties of collecting and preparing specimens of these heavy, toughly built, and diffi- cult-to-kill birds, as well as the remote distribu- tional range of the genus, further limited the num- bers of specimens available for siiid\. Remarkably, the history of the taxonomic con- sensus for Tachyeres mirrors a current phyloge- netic hspothesis for the genus (Fig, 2: Livezey Separate genus recognized by Lesson (1828). Tachyeres Flying and flightless species distinguished by King (1831) Continental and Falklond flightless potachonicus pteneres — brachypterus species distinguished by Murphy (1936). Two continental flightless species distinguished by Humphrey and Thompson (1981). ^- leucocephalus Fig. 2. Phylogenelic tree for Tachyeres. based on Live/.ey ( 19S6r) and Corbin ci uL ( l')SX). aiul aiuiolnlidii of the chronological coincidence of key diagnoses of species by taxonomists. STEAMER-DUCKS (ANATIDAE: TACHYEKES) 15 I^Sdc. C\)rhiii (7 cil. l'-)XS). The (irmlhological ciiinnuinilN tirst recogni/ed ;i single laxon (Tepie- sentinu" the aneestiir ot tlie geiuisi. and hiler dis- tinguished the tlighted lineage from the eollectiv e flightless (minxMed h\ the tirst branehing in the tree). Next. Magellanic T picncics v\as distin- guished taxdiioniically ticini Falkland T. hidihyptci IIS. which corresponds to the second In pothesi/ed vicariance event and associated spe- ciation. Finally, the recent recognition of /'. lciU(Kcplhilii\ parallels the last glaciation-related vicariance event presumed to have isolated / Iciicoccpluihis of Chubut from its sister-species 7. hi iiclixplcnis. This congruence of taxononiic his- tory with phslogeny is particLilarl\ mUessorthy because of the poor correspoiKlence. inferred ear- lier bs Miirph\ ( 1 436). betueen similarity of pkim- age aspect and ph\logenetic relationship. Variation in flying ability in Tlu Incirs has pre- occupied most taxonomists. and the impact ol lliyhilessness on the classitication ol the genus has been profound. Ironically, m light of current know ledge, ability to fly is at best an unreliable, composite character that is difticult to iletermine aiul is the result ot a lumiber of anatomical, behavioral, and environmental conditions. Pereyra ( I^.SO; 146) was one of tlie last authorities to recogni/e but a single species of Eik Incic.s al- though he (1943:227) listed two species in an earlier work: he explained the variation in flying abilit\ 111 the genus as strictly the result of sexual ditferences in body weight, the massive males being flightless but the lighter females being capable of low flight. It is known now that an appreciable proportion of male Flying Steamer- Ducks (T. pafciiiii'iiiciis) at some marine locali- ties are permanently flightless (HLnnphre\ and Live/ey l'-)S2b). Such locomotion-independent determinations, however, required systematic methods that were not available until recentlv. SYSTEMATIC REVIEW Rklationships of Tachyeres Of all the ornithologists recogni/mg more than one species of steamer-duck, only Dabbene ( 1 402 ) dill not consider them congeneric: the assignment of flightless steamer-ducks to Tachyeres and the flighted speciesto.W/c/v'/Vt'/zr,', by Dabbenet 1402), however, may have resulted as much from the taxononiic confusion that reigned at the turn of the century as from a perception of relationships. Most other systematists placed all steamer-ducks together in their own genus: the older name Mu iiipivnis Lesson, IX2X. being preoccupied in Pisces, was replaced by Tachyeres Owen. IS75. although the former was used infrequently into the twentieth century. Exceptions to this separate-genus treatment includeil assignments of steamer-ducks to the gen- eralized Linnaean laxa Aiiser (lor 'geese') and Alias doi" 'thicks') by early taxononiists (e.g., Gmelm I7SS. Latham 1790). Another view of the generic relalit)nships of steamer-ducks was iiuli- caled by several nineteenth-century ornithologists who included the steamer-ducks in already recog- ni/ed eenera of di\ iul! ducks: Ouleniia (currenth included in Mclaiiilia. scoters: King 1S2S). Fiili'^^iilii (currentiN A\ih\a. pochards: Schlegel IK66), and Caiiipu>laiiuiis (currently Caiiiptu- iliYiniiiis. Labrador Duck: Gray IS7I ). The perception of a relationship between Taihxcres and largely northern-hemisphere div- ing ducks was shared by a nuniber of other taxono- mists who. although they assigned the steamer- ducks to their own genus, indicated this view by their subfamilial classitications. These higher-level afliliations with diving ducks involveil sea-ducks i.Piilxsiicta.Somateria.Melaiutta.m^ABiicephala) and pochards ( Aythy ini ). and were inferred prima- rily on the basis of shared diving habits and di\'- ing-related anatomical characters (e.g.. Scott and Sharpe 19 12: Peters 1931: Delacour 1936; E^oellicher 1939. 1942: Hellmayr and Conover 194S: Verheyen 1953a. b. 1955. 1961: Simonetta 1963: Markham 1971). This 'alliance" between largely northern-hemisphere genera of di\ing duck and the austral steamer-ducks iiecessaril\ influ- enced early biogeographic sur\e\s of waterfowl (e.g., Sclater and Salvin IS76. Sclater ISSOa. Sclaterand Hudson I8S9, Casares 1940). 16 UNIV. KANSAS MUS. NAT. HISI'. MONOGRAPH NO. S On iho basis ol iho bclun ior. e Menial nioipliol- ogy. and syriiigcal anatomy ol stcanicr-dLicks. Delacour and Mayr (1945) concluded that the reseiiiblance ol Tuchxcirs to the eiders was super- licial and that steaniei-ducks were most closely related to the shelducks (their Tribe Tadorninii. This treatment was followed by most taxonomic discussions involving Tiuliycnw dining the next three decades, but most authorities chose to em- phasize the distinctiveness of the genus by placing it in a sepaiale tribe allied with the shelducks (Boetticher 1952: Delacour IM54: Gilliard 1M5S; Moynihan 1958; Johnsgard 1960. 1961a. b. |9ft.^i. 1965. I96,S. l97S;Lack 1974; Brush 1976; Winkler and Walters I9S,^; Kolbe 19841. An osteological study of \\aterfov\l led Woolfenilen ( 1961 ) to recommend that /(/iV/vcrcs be moved from the Tadornini to the dabbling ducks, tribe Anatini. Previously suggested by Ripley ( 1957). this 'aflinity" between the dabbling ducks and Tacliycrcs did not prove influential for subsequent writers in that none adopted this clas- sification. Several writers, however, subsequently retreated from a tirm assignment of Tacliycrcs to the Tadornini. either listing the genus between the shelducks anti the liabbling ducks (Meyer tie Schauensee 1966. 1970; Blake 1977; Johnsgard 1979) or stating that the intrafamilial relationships oi'Tachycrcs were unclear ( .Austin 1 96 1 ; Delacour 1964. Weller 1976). One series of investigations did provide some equivocal phenetie support for the "altinity' between Taclncrcs and the dabbling ducks; biochemical comparisons of uropygial se- cretions by Jacob (1977. I9S0. 19S2) and Jacob andZiswiler( I9S2) revealed similarities between those of steamer-ducks anti those oi Anus and the eiders (Soinalcrid). A phylogenetic analysis of Recent genera of walertbwl based on morphological characters con- hrmed the inclusion of Tinlncrcs within the Tadorninae (l,i\e/ey 1986a). with a less well sup ported hypothesis of close relationship between Tacliycrcs and two other 'aberrant" genera — the neotropical Torreiil Duck {Mcriiaiiciin urnuiui) and the New Zealand Blue Duck (IImiiciioIciiiiiiis iiialacorlnncluis). The corresponding classilica lion of TacliYcics — subtribe Merganetleae of the tribe radoiiiini in the aiuilul snhlamily ladorninae — is followed here. Relationships v\ithin the genus Tacliycrcs were inferred using morphological (Livezey l986c)andelecirophoretic tiata (Corbin c! ai. 1988). These studies indicated that the comparatively primitive but variable T. iniiaclioniciis is the sister-species to the three llightless species, and. of the latter, the medium- si/eii .Atlantic species (/'. Icucoccphalns and T. hracliyptcriis) are closest relatives. Sibley and Monroe (1990:.^2) considered the three llightless species as constituting a superspecies. but incorrectly considered piciicrcs to be the senior includetl specitic taxon. More surprising was the inclusion of Tacliycrcs in an enlargetl Tribe Anserini. an eclectic group com- prising the true geese, sheldgeese and shelducks. and the 'perching ducks' (Sibley and Monroe 1990); no empirical support for this arrangement was cited. Synonymies for Ta( idiri-s Members of the genus Tacliycrcs ha\e been given 25 different binomial (and trinomial) names (excludingapparent misspellings) involving seven genera. Most of the oldest taxa were ambiguous with respect to the four currently recognized spe- cies. Many provided no distinguishing characters or described broad distributional ranges, and are presumed to have referred to the entire known genus. Others provided localities of observation, which in some cases exclude certain llightless species from further consideration on distribu- tional grounds, but the information given does not permit a confident identitication of species. The tieieiniination of whether the birds were T. jhiiaclidiiiciis or members of a llightless species presents particular difficulties, and is often impos- sible for birds described from coastal habitats (see discussion of identification beyond). For example, the numerous early accounts of birds seen on saltwater in the f-alkland Islands (e.g.. Lesson 1826. Darwin I8.i9a, b) described birds of large size and apparently incapable of llight. I'nforlu- nalelv for purposes of identification, both charac- teristics can apply to both T paiacht>iiiciis and T. hnichypicriis. and the species are virtually inilis- lint!uishable in the field. STEAMER DliC'KS (ANATIDAI:: lACHYERES) 17 Llntoniinatcl\. lor dL-cadcs rulliiwiiiu ihc dc- \^:\■\\■)U^motl . pulcH limiu u\b\ Kinu( IS.il. 1X3*-'). most writers iikrIc no mention ol a second species of steamer-dnck (e.g.. Darwin iS34a, b). Lesson (1S37. IS.iS) was one ot the lirsi to accept the existence ot a second species of Tiniiycics. but interpreted the discovery to mean that the large flightless species was loiind in the F-alkkuuls (which lie had visited) and the smaller /'. ihiuiclinnlcus was found in the Straits of Magellan. The tax- onomy of Eyton ( IS.^S. 1869a) presents a special problem, in v\hich he recognized luo species — hrachxpicnis and palaclionictis — hut slated that both species v\erc Hightless and he provided sus- piciously similar measinements for the two forms. Most 19th-century iirmthologists. however, fol- lowed their prominent British colleagues — nota- bly Sclater. Cunnmgham. and Owen — in treating Tcichxcrcs as monoiypic. During this period, pro- ponents of the one-species \ iev\ varied in the distributional limits applied to steamer-ducks: e.g.. through the IS7()s. Sclater and his co-workers listed only collections and reconls of steamer- ducks from the l-alklanil Islands, but subsequenth extended the distributional limits of the genus to the continent. Salvadori (1X95:373) wfote that steamer-ducks were '"Confined to Straits of Magellan and Falklands."' Reed ( 1939) was one of the last authors to recogni/e but two species of steamer-duck — Tacliycrcs hrarlnplcnis and T. pcikicluiiiicus — and was alone in listing both for the inland, moimtainous Argentine province of Neuquen! Similarls. Junge( 1939) included moun- tain lakes among the habitats of the single taxon he recognized for southern Chile. T. pauu luniuus. a species he described as flightless. Both aiuhorities may have been misled by the inexplicably inaccu- rate species disii ibutions given by Zotta (1935:1X0). Consequently, we list midcr the generic ac- coimi the lollou mg classes of references: ( 1 ) ref- erences which explicitly or are presLuiied to in- clude the entire genus Tacliycrcs imder a single taxon: (2 1 references to apparently tlightless steamer-ducks, generally with locality informa- tion, but with descriptions inadequate for excki- sion of /, piikniiii/iiciis: aiul (3) references to steamer-ducks, presumed flightless or otherwise. Ill which the ilistributional limits given include the ranges of two or more species of flightless Tacliycrcs. For these nonspecific citations we in- clude a single-letter designation (in brackets) to iiulicate the geographic region concerned, thereby defining the subset of species that ina\ have been included. These designations are: G general: referred to entire genus (often con- sidered to be monotypic ). or the region poorly delined or included entire distributional range of genus. F Falkland Islands: T. hiiicliypicrus and/or T. pataclwniciis involved. T Tierra del Fuego (including Isia de los Estados); 7'. ptcncrcs and/or T. patachoiiicus involved. A Atlantic coast of Patagonia (coastal Argentina north of Tierra del Fuego): involved T. paUii htiiiicus and/or possibly T. Iciicoccplialiis. P Pacific coast of Patagonia (Chi lean coast north of Tierra del Fuego): involved 7. /'?(7;c;c.s and/ or 7. palachoniciis. Sources clearly referring to flightless forms but as distinct only from the flying form (i.e., there was no diagnostic or distributional information by which to determine which flightless form was intended), are included under the flightless species included in the distributional ranges described (annotated as "in part"). References to cmrently recognized species (based on examination of listed specimens, descriptions, illustrations, observations of birds in flight or on inland lakes, inability to fly in captivity, and/or distributional information) are listed under the corresponding current ta\a. Pages listed include all references to the taxon in the works. Apparent misspellings also are in- cluded (indicated by asterisks), as are errors in gender, if the erroneous taxa were used consis- tently m the works. Other taxonomic complica- tions are annotated following the individual cita- tions. Etymology of species names was describeil by Ciotch (1981 ). Published vernacular names are listed by language and are followed by the earliest references to each name. Suprageneric classifica- tion follows Livezes ( 1986a). 18 L:N1V. KANSAS MlIS. NAT. HIST. MONOGRAPH NO. 8 Oicici' .AnsciiloiniCN (Waglcr. 1S31 ) Suborder Anseres Wagler. 1831 Family Analidae Vigors. 1825 Subraniiiy Tadt)riiinac Reichenhach, 18.^2 Tribe Tadornini Delacour and Mayr, 1945 Sublrihe Mergaiiclteae Bonaparte. 1853 Genus Taciiyeres Owen, 1875 Steamer-Di ( KS ■n)i,wu-ilca (7;;/.«7/.v/.v.— Molina (1782:239) |P|; considered synonymous with "Microptcnis cincrciis Gray" by Philippi ( 1867:793) but not by Deautier and Steullet (1930:474). Alias cliicrcu. — Gmelin ( 1788:506 |F.T|); Garnol (1826:59 I F|): Brelim ( 183 1:903 |G|): Menem ( 1 841 :29 |G| ): Giebel ( 1 872:347 |G|): Frauscher (1 894a: 174 iT|). ,4/((V.v hnwhyplcni. — Latham ( 1 790:834 | F| ); Qut)y and Gaimard (1824:347 |G1): Garnot (1826:59 |F|): Reichenbach (I836:entry 394 |G|): Dar- win (1839a:257 [F]: 18.Wb:l90 |F1). Aiisvr cincrciis. — Bonnaterre (1790:112 |F|). Auscr hrachypiciiis.—W'icUUn (1818:344 |F|): Dumeril (1825:470 |G|). Alias hrai Inplcra el i incrca. — Lesson ( 1826:227- 228|G|: I831:630|F|: I837:533|F|: 1838:720 |F|). Micniplcrus hiiichxpicnis. — Lesson ( 1828:416 |F|. gender of species not gi\en): Gould (1841:136 |F|): Lichtenstein (1854:100 |P|): Wood ( 1 862:735 |G1): Hubbard ( 1907:2 1 7 |(i |). Xficriipicnis (incrca. — Reichenbach (1845:t. 77. illus. 894 |G|). Microptcnis cincrcns. — G. R. Gra\' ( 1840:74 |G|; 1844:623 |G|i: .1. E. Gray (1844:140 |G|): StrickIand(1841:39|G|):Hartlaub(l846:l9|Fl): Des Murs (1847:457 |P.T|); Reichenbach (1852: plate VIII. table VII |G|):Boeck( 1 855:5 II |P|): Bonaparte (1856:651 |G|): Gemiain (1860:315 |P|): .Sclaier( 1860:389 \l-\: 1867:335. .MO |P1): Pelzein ( 1 865: 1 39 [P| ): Cunningham ( I S68: 1 27 |F.T|: I87lc:262 |F.T1: Giglioli\ 1868:498 |T|): Philippi (1867:793 |P|: 1868:283. 309 |P|): .Sclater and Salvint 1868: 189 |T|: 1873: 130 |T|): Thomson ( 1 877:205 | F.Tl ): Vinciguerra ( 1 883:58 |T|): Lalaslc( 1893:122 |T|); Paesslert 1909:103 IF.T.Pj). *|/\/;(;,s| piciicros. — Attributed erroneously to Forster (1844:338) by Bonaparte (1856:651). .Salvadori (1895:374). Scott and Sharpe (1912:489). and Phillips (1925:288). Fnlii-nla cinerea. — Schlegel (1866:13. 118 |F|; 1872:274 1G|): Sundevall (1872:149 |G|). Cainpiolainiiis |subgenus indeterminate! (7/UT('/(.s.— Gray (1871:88 |G|). Tacliycrcs hracliypicrns. — Owen ( 1875:254. 258. 266. 272 |G1: 1879:366 |G|): Collin (1927:54 |G|): Peters (193 1:76 |G|): Pereyra (1950:196 IT.F.PI). I'achycrcs cincrcns. — Sclater and Sal\ in ( I 876:402 |G|; 1878:437 |T|): Sclater (l879b:3U) IT]: 1 88 1 : 1 50 |T| ): Sharpe ( 1 89 1 :309 | Fj: 1 899b:224 |G|): Reichenow ( I882a:48 |G|: 1 882b: 1 7 |G|): Coppinger (1883:56. 61-62 |T|): Stejneger (1885:149 |G|): MacFarlane (1887:202 |F.fl): Burmeisier( 1888:248 I A|): Ridgway ( 1889: 138 |T|): Sclater and Hudson (1889:137 |F.T|): Tristram (1889:47 |T|): Lucas (I89I:I.W |T1): James (1892:10 |P|): Gadow (1893:154 |T|: 1902:169 |G|): Newton (1894:518 |F.T|: 1895:597 |F.T|: 1896:737 |F.T|: 1899:518. 597 IF.Tj): .Salvadori (1895:326. 373 |G|; 1900:633 IGj); Lane (1897:195 |P|): Beddard (1898:456. 460. 466. 468 |G|): Martens (1900:25 |G1): Dabbenet l9l4:296|G|):()ates( I9()2:I84|F.T|): Nicoll (1904:49 |r|); Vallentin (1904:33 [F|): Hubbard (1907:217 |G|: Reed (1907:105 |P|): Wilton cl al. (1908:6. 62 |F|): Fvans ( 1909:121 |G|): Knosvlton and Ridgway (1909:195 |G|); Townscnd (1909:242 IT]; |9|():6 [T]): Cobb ( 1 9 1 0:66 1 1- 1; 1 933:80 1 1- 1 ): guijada-B. ( 1 9 10:339 |G|); Mitchell (191 1 :5l4|G|):Paessler( 191 1: 128 |T|: 1913:41.43.48 1T|: 1914:272 |T|; 1915:60 |T|): Brabourne and Chubb (191 2:57 |T.F| ): Scott and Shaipe (1912:487. 489-492. 498 1 G | ): Bertoni (1913:76 |G|): Shuleldt (1913:210-215. 217- 220 |G|): Brooks (1917:155 |F|); Brooks in Phillips (1^17:117-118 IF. T]); Aiion>moiis (1918:205 |F|); Finn (1924:138 |G|): Lynch Arribal/aga (1924:270 iA.T|): Chapman ( 1926: l20|P|):Heinroih(l929:532|G|): Palmer (li}34;4()y6 |G|); Schmidt (1943:55 |G1): Hamilton (1946: 1 31 1 1- 1 ); Glegg ( 1947:433 |F|): Meunicr (1959:453 |G|); Neilson cl al. (1960:2466 |Cr|). STEAMER-DUCKS i ANATIDAE: I AC //) 7 /^7 S) 19 .\/(.s(7- ( iiicrcii. — Milne-Edwards ( ISS2:4n |Ci|)- AiiiisiMn nipicnis)ciiici-ciis. — FrauxclK-r( lSM4b: 205 |T|1. Tachycrcs cincrca. — Beddard (1897:467 |G|): Boker(1935::()2 |C,|). '^Trachycii's (//k'/CH.v.— Vallenlin { U)()| :35() |F|). Tachycrcs hruchxpicra- — Peters (1931:176 |("i|): Boetlieher (1939:434 |G|); Berlicv ( 19.S():,SS1 Ki|): Simnneita ( 1963:127 |Ci|). Vernacular Names Race-horse. — Byron (1773:?()); Hawkesworih (1773:411); Cook (1777:186): Forster (1777:492): Buffon (1798:159: 1812:369). Loggerhead. — Penrose (1775:35): Claylon (1776:104). Loggerhead goose. — Penrose (1775:35); Latham (1785:439). Loggerhead duck. — Forster ( 1777:493). Steamer-duck. — King ( 1839:35). Sea-horse.— Blaauw (1916:448). Spiinish Ouethu.— Molina ( 1782:239). Quetu.— Des Muis (1847:457). Cagues.— Des Murs (1847:457). Quetru. — Germam ( 1860:315). Oueira.— Giebel (1872:347). Palo quetru. — James ( 1892: 10). Quelar.— Lane (1897:195). Quaitar.— Lane (1897:195). Palo vapor.— Blaauw (1912:67). Quetri).— Phillips (1925:287). Quettio. — Chapman ( 1933:361 ). Pato vapor grande no volador. — Pereyra (1950:196). Duhh Stoomboot-eend. -Schle^el (1872:274). ■Reichcnbach ( I836:entry 394). R i e s e n e n t e . — R e i c h e n o w (jcyi)ian Kur/llugelente. P a I a g o n i s c h (1882a:48). Dampt'ergans. — Frauscher ( 1894a: 174). r)uetra der Patagonier. — Fiauscher ( 1894a: I 74 1 tiraueii Tauchente.— Cobb ( 1910:20-21 ). DamplschiHente. — Agosiini ( 1924: 114). I- rciicli Oye grise. — Pernety ( 1769:576). Oye du plein. — Pernety ( 1769:576). Canard-lourdaut. — Cook ( 1 778:285 ). Canard au\ ailes courtes. — Quoy ami Gamiard ( 1824:139). (Jie du plain. — Lessi)n ( 1826:228). Canard-loiudaud. — Lesson ( 1826:228). Canard a ailes courtes. — Reichenbach ( I836:en- try 394). Canard micropiere. — Oustalet ( I891:B2I2). Canard (a) vapeur. — Oustalet ( I891:B2I2). Canard cendre.— Cobb ( 1910:20-2 I ). Canard geant. — Boubier ( 1934:85). Macreuse australe. — Housse (1942:329). Canard plongeur de Patagonie. — Berlioz (1950:881). Ihllhin Pato a vapor. — Agostmi ( 1924:1 14). Aniira a vapore. — Agostini ( 1955:74). C:c( lii>sli>]\d Kachyne.— Kolbe (1984:170). Russian y iKii - nopoxoa. — Kolbe ( 1984: 170). Japanese .— Yamashina (1986:70) Fiiciiian: (tribe not given) Karawiis-poug. — Coppinger ( 1883:122). Content Tiuhycrcs comprises totu species, one com- paratnelx widespread, geographicallv variable, and (largely) (lighted species, and three mutually allopatric. marine-coastal, flightless species: Fly- ing Steamer-Duckt /./).^6); and While-headed Flightless Steamer-Duck (7. Icucdtcpluilus). an overlooked or misidcntitied endemic ot coastal Chubut, Argentina, described by Humphrey and Thompson (1981). TviM-: Spf-Cies The type species of the genus Tacliycrcs is. by monotypy. Anas hruchypicra Latham 1790. i.e.. the species name was that to which Owen ( 1S7.^) reterred in naming the genus Tachycrcs. A neotype for I. hnitliypicnis is designated below. Fortu- nately, this species (as currently delimited) is rep- resentative of the genus for several reasons: {\)T. hrachypicriis shares all the diagnostic characters of the genus: (2) the species is flightless (a distinc- tive character rare among the Anatidae btit shared by T. ptcncrcs. '['. Icmoccphalus. and some males of T. pauiclioniciis). of moderate size, and its plumage pattern is very similar to those of its congeners (with the possible exception of the unique 1. picucrcs): {?>] T. hnichxptcnis is the species mosi frcquenlK kept in captivitv: and (4) this species was of historical importance, and ref- erences to this form occur in the writings of most early explorers and naturalists (e.g.. Lesson IS.^ 1 : Darwin IS.VJa. b: Ciould 1S4I: Sclaler lS61a). BkII I Dl S( kllMION Steamer-ducks are metlium to large Fuego- l^atagonian marine-lilloral (all species) and Iresh- ualer (one species) thicks, are predominantly battleship gray with lov\er breast, belly, and most secondaries white, sluiw variable pattern anti col- oration of the head, and have moderately elongate, recurved central reclrices. Members of the genus lack any metallic coloration anil are sexually di- chromatic in some definitive plumages. Males are larger and more robust (bull -necketl ) than females. Bills of adult males are largely bright orange. Except in juveniles and subailulls. the leet are bright yellow-orange. DisrRiBirioN Members ot the genus are limited in distribu- tion to marine coasts and (in 7. palachoiucus) freshwater, primarily mountain lakes, throughout southern .Argentina. Chile, and in the Falkland Islands (Fig. 3). The northern limit of the conti- nental range of the genus can be approximated by a line connecting Concepciiin. Chile vi> ith Viedma, Argentina. The marine-litioral range of the flighted species o\erlaps. at least seasonalh. those of each of the three, mutually allopatric llightless species. Tachyeres patachomcvs (Kinc;, 1831 ) Fi.viNc Steamf.r-Di ( K Micropicriis pataihonuiis. — King ( 1 S3 1:15; 1 S3y:.S42); Lesson ( 1837:533: l838:720):Eyton (1838:143: 1 869a: 100-101 ): Abbott (1861:162): Sclater (186lb:46): Giglioli ( 1 875:934 ): Oustalet ( 1 89 1 : 2 1 2-2 1 6. 2 1 8. 220- 222. 224-226. 227-23 1 . plate 5. in part): Sclater (1892:173-174); Dabbene (1902:403-404). ■''MicniptcilDliispiitcuiuiiiit litis. — Eyton ( 1 838:50; 1869b: plate 18. reprinting of tigure from 1838 work with misspelling). Micropicriis puruchnnica. — Eston ( 1856:348). Micropicriis ciiicrcus. — Cox (1863:235. m part): Sclater and Salvin (1870:499): Cunningham (I871a:493. in part); Paessler (1909:103. in part). {Micropicriis niucroptenis. — Giglioli ( 1875:934). parenthetical suggestion of alternate name.l Micropicriis Inncliyptcriis. — Moreno ( I879:| 165. 173|). '''Micropicriis hriuiiiplcriis. — Bove ( 1883:13). 'Micropicriis paliaclioniciis. — Vinciguerra (1883:58). "■Micropicriis pcihr^oniciis. — Carbajal ( 1 900:282 ). Tiicliycrcs ciiicrciis. — Sclater (1881:1 07. in part ); Sharpe ( 1 88 1 : 1 3. in part ): Craw sha\ ( 1 907: 1 1 0, in part): Nicoll ( 1908:163. in part); Skottsberg ( 1 9 1 1 :47 ); Scott and Sharpe (191 2:487. in part); Phillips ( 1 925: 1 34. 287-288. in pari ); Weimore (1926:418). Tuclixcrcs puiiiclioiiiciis. — llolmherg ( 1895: |22l|): Dabbene (1910:233: 1932:205-206); .Sclater (1913:315); Blaauw (1916:488-489, STEAMER-DUCKS (ANATIDAE: TACHYERES) 21 -40° '5° W -35° S Concepcio Puert diagonal barruig (meludes coastal arul uiland areas), and the coastal ranges ol the three (mutually allopatric) tlighlless species are shown in stipple. 97 UNIV. KANSAS MKS. NAT. IlISI MONOCRAPIl NO. X 441; 1417:274-276; 1421:5S): Mogcnscn (1417:85): Anonymous (1420:77): Bcnncll (1924:280-282: 1926:327); Vallenlin (1924: 325): Snouckaert van Schauberg (1926:150- 151 ): Sirescmanii ( 1927:47): Helhnayr ( 1932; 336-337): Boubier (1934:85-86): Lowe (1934:449-482.484-487.489^93: 1935:4261: Reynolds (1934:351): Re\nolds /;/ Lowe (1934:470-472.477-179); Reynokls( 1935:85): Zotta (1935: 180; 1944:30): Bullock ( 1936: 137); Murphy (1936:199. 208. 953-956. 958. 964- 965,968-969): Steulleland Deautier( 1936:.Vi4. 366-367); Junge (1939: 1 66. in part): Laubiiiann (1940:18-20): Morrison (1940:254): llousse (1942:177: 1945:92: 1948:329); Stonor (1942:17-18): Pereyra (1943:227): Trimble ( 1943:420); Delacour and Mayr ( 1945: 15. 38; 1949:42, 63): Parques Nacional Argentina (1947:39); Hellmayr and Conover (1948:374- 377); Olrog (1948:473: 1950:518: 1959:70; 1963:100: 1968a:l 1 1: 1968b:plate 11; 1979:50; 1984:92. 269); Yane/ (1948:154: 1949:8-10): Ripley (1950:5; 1957:225); Goodall ci al. (1951:162-163): Boettieher (1952:23. 68-69, 91); Pergolani de Costa (1953:36: 1970:35): Verheyen (1953a:384. 410. 434-435: I953b:463. 486-487: 1955:2.15): Delacour ( 1954:271. 276-277; 1964:335): Philippi-B. ci al. (1954:29); Scott (1954:61: 1972:48); Agostim ( 1955:74): Holgersen( 1957:59);Tour (1957:162); Bo (1958:39); Moynihan (1958:183. 200-201): Van Tyne and Berger (1959:234); Cawkell <■/ al. (1960:216); (). .S. Petlmgill (1960:606); .Sclionwelter( I960: 1 3 1 ); Cawkell and Hamilton (1961:15): Johnsgard (1961b:64: 14(,2:14(); 1965:94; 1968:105: 1978:135; 1979:453): Berndt and Meise (1962:192): Godoy (1963:31): Philippi-B. (1964:46): Bernalh (1965:98); Caik|iiisi (1965:232): .lohnson (1965:195-196; 1969:5: 1970:2): McKinne\ (1965:195): Peltingill (1965:71): .Smith (1465:56); .lohansen (1966:231): Meyer de .Schauensee (1966:40: 1970:33; 1982:33): StresemannandSiresemann (1966:305): /apata (1467:364): Lack (1968:347); Weller (1468:200: 1469:128; 1472:26.37: I975a:295: 1975b:87: 197.5c:ll(); 1976:45: 1980:26); llumphre> <7,//, ( 1470:129- 130. 135-139); MarkhanK 1970:46: 1971:48); Sibley and Ahlquist (1972:93): Strange (1972a:256); Bock (1973:208): Boswall ( 1973b:248); Duguy (1973:6: possibly included /; leiKoceplialiis): Jehl ( 1973: 129); Jehl ct al. ( 1 973:6 1 . may have included 7'. leiicocephaliis): Vigil ( 1473:69-70): Jory ('?(//.( 1974: 132): Lack (1974:85): MacLean (1974:193); Merne (1974:34. 78): Schlatter (1974:2: 1976a: 14: I976b:137. 140; 1979:163): Morony ci al. ( 1975:2 1): Woods (1975: 123:1 982:50): Gruson (1976:11); Jehl and Rumboll (1976:146); Kiihnemann ( 1 976: 157); Vcnegas C. ( 1 976: 1 77- 178. 183): Wolters( 1976:98): Blake( 1977:227): Daciuk ( 1 977:363. 37 1 ; probably included in T. Icucocephalits): Jacob (1977:52. 54-58: 1 982:87 ):Navas( 1 977:35,86): Reed (1977:27): Navas and Bo (1977:79): Clements ( 1978:27): De la Peiia (1978:57: 1986:79; 1987:39); Soothill and Whitehead {1978:280-281): Blandamer and Burton (1979:132): Goodall (1979:76): Todd (1979: 160): Hillgarth and Kear ( 1979: 142): Venegas C. and Jory H. (1979:73): Conlreras ct al. (1980:45): Howard and Moore (1980:71: 1984:71): Erize ct al. (1981:131. 178. 194): Goich (1481:83): Humphrey and Thompson ( 1 48 1 : 1 . 3. 5-6, 8): Storer ( 1 48 1 :53; 1484:637): Venegas C, (1981:217: 1986:11. 61); Araya (1982:5): Humphrey and Livezey (1982a:l-2. 10. 12. 15.21-22: I982b:368.370. 371: 1485:444-451); Jacob and Ziswili (1982:274. 276): Live/ey and Humphrey (1982:12-16; 1983:485-486; 1984a:257: 1984b:368-376: 1985:154-156: 1986:540-553. 556): Scherer and Hilsberg (1482:.360, 373); Corhm (1483:216): Carpi (1484:116): Daciuk and Heber(1984:174):Kolbe( 1984:170, 172); Walters ( 1984: 1 8): Edwards (1985:2 1 ): FjeldsS (1985:111): Harrison (1985:665); Live/ey ct al. (1985:18-19: 1986:445-450): Murray (1985:567): Narosky ct al. (1985:11): Nuechiorlcm.ind Storer ( I985a:87; 1985a:568): Raikow (1985:82. 86-87); Araya M. ct al. (1986: 116): Clark ( 1986: lOO); Live/ey (I986b:51 1-512. 515-523; I486c:458. 460- 466. 467: 1484a:l. 3. 6-15. 17. 20-26. 28-28, 31_33. 40: 1989b: 1 8 1-1 82: I989c:428; 1490:661): McGowan (1986:306; 1484:538, STEAMF.R-I)l CKS lANATlDAE: TACflYERFS) 23 .•S4:); VaniashiiuK U'XfrTO); Duiiiiiiii: ( l'-)S7:23): lliimpliiex (7 (//, ( IMS7:6. IX-l;iilcd m;ip o\ the distribution of /, puhuiuiniciis based on speeiniens. published reeords. and atlequately doeurneiited, unpublished observations. Speeiniens are shown as sohd eireles. sight leeorils as open eireles; evidenee ol breedins; (nests, broods) is indieateil b\ diai;onal slashes. Cliilc north to the \teinit_\ of .Satiltaiiii (3.V'S): or the l'io\ itiec of Nuble ( Araya M. c/ <;/. 10S6). this species occurs at least inlrec|uciill\ as far (ioodall (7 1//. ( IM.'S 1 : 16.M ga\c its nortiierti limits tiorth as 39"S in CTiilc (M. Christie, utipiiblished in Chile as Bahia dc Talcahuaiio on the coast ami inventory tor Parqtics Nacionalcs dc .Arueiitina) Niihlc mlami. I-jcklsa ami Kiabbe (I')4(1:I2()) STEAMER-DUCKS (ANATIDAE; TACHYHRES) 27 dcsL-nlxHl / inihnhoiiicus as: "('omnioii at 700- T \CHYERES BRACHYP I liKl S (LaTHAM, 1790) 1200 111 (111 hanvn upland plateaus ol iiilaiul Sla F.M.Kl.AM) FlJCHTLKSS StEAMKR-DicK Cru/ and on the Sonuineuia plateau ol' Rio Neuro. Arg.. and in Nubie aseends to I SOO in.'" The Amis IvachxpieriL — l.athani ( 1 740:S34; listed ni northeinniost Atlanlie specimen ol /, iniituli- generic syiion\m\. iiia\ ha\e incliided T. onlciis Ironi Rio Negro Prinince. Argentina (Scott pauu honii tis). and Sharpe 1M()4). and sight records troiii Bahia Mu lopicnis Ivdt Inptcrus. — E;_Nton (lS.vS:144. in San Bias. Buenos Aires Pro\iiice(M. Nines. |icrs, pail; IS(i4a:101. in parti. comiii.). and Cosia Bonita. Buenos Aires Pro\ - '■ Mu lophi us hi in iixuiits. — Eyion (!S.^d:.i4S. in ince (Narosky ci al. \'-)'ts>. Narosky and Fiameni part). !'-)S7) probabK pertain to casual, nonbreeding Muinpiciiis viiicrcus. — Gould ( I S.SM:96); Abbott vagrants. (ISO 1: 150. 161 ); Sclater( lS(ila:367; 1868:529; Although inland records of Flying Steamer- 1872:256; 1877:337); Cunningham (1 87 la:493. Ducks are most Irequentlx maile on high-altilude in part). lakes, the species also has been reported on low - Tm lixcics cinereiis. — Sclater l 1 879a:376: altitude lakes in Santa Cru/. Argentina and in 1880b:529: 188 1:107. m part; 1882:792; riverine habitats near Lago Viedma. Santa Cru/. 1883:442; 1896:450): Holmberg (1895:|22l |. Argentina, it is believed widely that / ^ P;""'; Dabbene (1902:403-404, in part); pannlionuus on the Falklands breeds onlv on Ramsay ( 191 5:21 1 ); Wace ( 1921 :201 ): Bennett freshwater lakes (Weller 1972, 1976), and that (1^^24:280-282: 1^)26:327. in part): Vallentin the species is uncommon throughout the archi- < 1^24:322): Phillips (1925:134, 287-288, in pelauo (Strange 1972b:2()6). It is likely that birds P'""- Snouckaert van Schauberg (1926:150- breedino on fi^shwater. both on the continent and '-^l- "^ P^"''*- Selh-Smith (1927:245): Smyth ,, c iTi 1 , , r ,1 (1927:12): Stresemann (1927:47, in part); the Falklands, nunc lo marine coasts lor tlic ' r. 11,1 wi^i i-7;> . . r Boubier ( 1 934:85-86, in part ) winter. RcNUolds (//) Lowe 19.i4:47.^) wrote ol /. , ^ putucliiiiiiiiis in Isla Grande, Tierra del Fuego: "Tn winter it is restricted to the coast, where in Micniplcntspaiachdiuciis. — Oustalet ( 18M1 :2 12- 216.218. 220-222. 224-226, 227-23 I , plate 5, , I- 1 ,■ 111 P'li"- summer man\ breed; but others penetrate tar -r , , , , ,,>^, n,, i.,., ' Taclixcrcs hiiU hxpicnis. — Lowe ( l'^)-i4:479-4S8, inland, spreadiiiL' wherever there is water from ,,,,. ,,,., . ., r> ii • i ,i(iii i-i,\ ' - 490-493, in part ):Revnolds(// Lowe ( 1 934:470- the sea to the mountains." However, Finn ( 1924:139), who recogni/ed but a single species 472. 474-177, m part); Zotta (1935:180, in pan: P)44:30. in pari); MiirpliN ( 1936:194.208, of Tcninercs. wrote: "...In Tierra del Fuego they 4xV956. 958, 961-962, 964-965, 968-969); Isteamer-ducksl are found on fresh water also, Steullet and Deautier ( 1936:365-367, in part); and when this Iree/es in winter, often die m ^^.^.^^ (1939:34-35, in part); Laubmann trying to tiiul other quarters." This remark may ( |i)4(); \t))-^ Boetticher ( 1942:42: 1952:23, 68, stem from the statement of Crawshay ( 1907: 1 14- i,| ,. Sionor ( 1942: 1 7-1 8): Delacour and Mayr 115): "[-requently I found these birds Istcamer- (1445:15. 38: 1949:42. 63): Hellmayr and ducksl lying dead inland, starved to death appar- Conover (1948:374-376); Goodall cl al. ently. through the free/ing of their waters." In (1951:162): Anonymous (1952:49); Sladen contrast, but without dociimentar\ evidence or ( 1 '■)52:222 ); Pergolani de Costa (1953:36; references, SoothiU and Whitehead (1978:280) 1970:35): Delacour ( 1954:273, 276): Moynihan stated that the species: ■•In winter, tlies less often (1958:183); Olrog (1959:70: 1963:100; and can be found resting or sleeping on fro/en I968a:110: I968b:plate 11: 1979:50; 1984:92, inland waters, but m Isla Grande (Tierra del 269); Van Tyne and Berger (1959:233-234; Fuego) it is restricted to the coast during winter 1976:397): Cawkell ct al. (1960:217); E. R. months." ^ Peltiiigill(l9(,():145):O.S.Peltingill( 1960:606: 28 UNIV. KANSAS MUS. NAT. HIST. MONfXiRAPII NO. 8 UXi.^i:?!: 19S2:')2()); Schoinvcltei- ( lM6():l.^li: 7(/(7mTc.s7)/(7/r;<'v—ll()Lisse (194.^:91: m48:.^2M). C'avvkell ami llamillon (1961:1.^, 1.^); Beriuil *Tl: and Meisc (I962;1M2): Johnsgarii (1^62:l.^l; 34). 1 965:9,^: 1 96S: 1 05: 1 97S: 1 .38: 1 979:452 ): ^Tachycirs hrainlixpicra.—KcnLktixh [ 1952: 187); PiiiK-c Philip (1962:54): (iodoy (196.^:31): Coll ( 1953a:4!4: 1953b:651). Carlquisi (1965:231-233. in part): McKiniicy '■■'rachycre.s hracliyapicnis. — Gruson (1976:11). (1965:212): Smith (1965:55): Johaiisen ■■'Tacliycrtcs hnnhyplcrus. — Adams and ( 1966:23 1 ): Meyer de Schauensee ( 1966:40): Templeton (1979:38). Siresemannand Stresemann ( 1966:305): Gewalt Tachxcirspaiachoniviis. — WitienhergerandTilson (1968:188-189): Griswold (1968:32): (1980:211). Johnstone (1968:127): Lack (1968:347): *Tarhycrc\ hruchyllcrus. —Prowuc (1983:19: Schmiilt (1969:125): Raikou (1970:570: ii-)s4:453). 1985:82): Woods (1970:18-19. 1975:118: */(,r/nr(TC,v /.;■,/< 7/v/)/<'n(.v.— McGowan (1982: 1980:49): Weller(1971:l()8: 1972:26,44. plate 215). 1: 1975a:295: 1975c:110: 1976:45): Scott (1972:48): Strange (I972a:256): Bock (1973:208): L.aek ( 1974:85): Merne (1974:34. Vern,\cll..\k N.amf.s 80): Daciuk (1975:172: 1976:27): Morony er al. ( 1975: 12): Welly ( 1975:239. 458: 1982:282. ^-",i,'/'.v/' 543): Brush (1976:482): Wolters (1976:98): Logger-head.— Bennett (1924:280-282). Jacob (1977:52): Navas (1977:35-36): Navas Sea logaer. — Bennett ( 1924:281 and Bo (1977:79): Clements (1978:28): De la Logger (duck).— Bennett ( 1926:327). Pena (1978:58: 1986:81): Kear (1978:61): Falkland Flightless Steamer Duck.-Murphy Soothill and Whitehead ( 1978:281 ):Blandamer (1936:9.i4). in . , 1.1-7(1 T :!Tv u II IN/11 Falkland Steamer Duck. — Clements ( 1978:28). and Burlon ( 1979:132): Bosvvall and Maclver ( 1979:75-76): Todd ( 1979: 160. 162): Howard andMoore(l98():7 1: 1984:71 ):Tonni( 1980: II. V""""'/' ,,, , ,,,,.,> ,w> ,-• 1 ,,>u, uT Remero vek)/. eortas alas. — Housse ( 1 94.1:91 ). I4i: Warham (1980:98): Gotch (198 1:82): , , .. , ■ r. , . », ,, , , ,,,, ,,,„, , , , ,„, Palo vapor de Malvinas. — Deiacour and Mayr Humnhrev and I hompson (1981:1. .1-6. 19): ,,.,;,-, " (1949:63). Ilumphre\ and Live/e\ (l982a:l-2. 21-22'. ,, , , »» 1 ■ r> i ■ 1 <-■ . ' ■ • Palo vaiior de Lis Mahmas. — Peraolam de C osta 1982b:368. 371: I98.'^:944-9.M ); Mlikovsky ,u)sV^6 (1982:728): Carpi (1984:116): Live/ev and ,, " ' '" '', . ., ,^ , ,,,,,, ... ' - Pato-vapor inahniero. — MacDonaulH 1941 :45). Humphrey (1 982: 1 2: 1983:485-486: 1 984a: 257- 259: I984b:368. 375-376: 1985:154-156: ,. I986:.54(). .S49. 551-556): .Seherer and Hilsherg M,tteklamprsch,riente.-Berndt and Meise (1 982:360): Daciuk and lleber( 1 984:1 74 cKolbe (ii)6"'-|92) (1984:66. 170-172): Mendall ,7 ,_,/,( I984:,^06): ,.,iKhuul-Damplsch,llente.-Bock (1973:208): Wolters ( 1976:98). Walters ( 1 984: 1 8 ): Etiwards ( 1 985:2 1 ): Harrison (1985:655): Nuechterlein and Slorer ( 1985:87): Livezey ( 19K6b:5 1 2: I986c:458. 460-463. 465: /-,■,,,„■/, 1989a: I -3.. 5-7. 9- 1 6. 20-22. 24-28. 3 1-33. 40: Canard aux ailes courtes.-Lesson (1837:533: 1989b: 1 82): Live/ey (■/«/. (1 986:44.5-448.450): 1838:720). McGowan (1986:305, 306): Yamashina Canard-vapeur des lies lalkland.— Johnsgard (1986:70): Narosky and ^/uneia (1987:79): (1978:138). Cabal (1988:24): Gauthier (1988:113): Madge and Burn (1988:58.183): Ryan ci al. ( 1988:29): Czcvlu>sl,n<,k Siblev anti Monroe (1990:32). Kachvne kr:ilkokokiidla.— Kolbe ( 1984:171). STEAMER-DLICKS (ANATIDAE: IMIDhRES) t>ojiKJieHacKasi yTKii-iiapoxoa — KolixM 1^84; 171). Japuiuwc y-^-i]'^ ^Yamashin;i ( 14X6:70). Okkiinal Di;,s(kii'IK)\ and Tvpf. This species, and ihe MagellaiiiL- /, piciicics (below), were collectively dit'terentiaied trom the smaller, flighted Tpcnaclioiiiiiisby luinieroLis w ork- ers since King (1831 ). Although nian\ ol the early accounts ot steamer-ducks were based on obser\ a- tions of apparently flightless birds in the Falkland Islands (e.g.. Lesson 1826. Darwin 183'-)b). com- paratively tew authorities included specimens from the Falklanil Islands in their comparisims: excep- tions included Abbott ( 1861 ). Bennett ( 1M24. 1926). and Phillips ( 1425. in part). The original description by Latham ( 1790:834) included as diagnostic char- acters of the species its orange bill, gray body, short wings, white wing patches, and large size (between that of a goose and a swan). In his 1790 work. Latham gave the range of the species as the Falkland Islands, whereas in his earlier work he ( 1785:439) included Staten Island (Isia de los Estados). This species was diagnosed as specihcally distinct from continental flightless steamer-ducks by Murphy (1936). No types were designated and no t\ pe material is known. Accordingly, we designate as neotype the following skin specimen, held at the American Museum of Natural History. New >'ork: Specimen no. 443786 — Male: collected at Port Stanley. Fast Falkland Islands; on 27 October 1915: by R. H. Beck. Si AsmRM Mi.Ast KiiMf-NTS or Adi its (mean + standard deviation, range. /;) T.iUil wvr^ht (g).— Males: 4228 ± 443. 3300- 4800. 12. Females: 3519 ± 336. 2900-1196. II. H//;,','/c/(,t;r/M arc. mm).— Males: 276+13.238- 296. 24. Females: 268 ± 12. 245-292. 15. Ciilnicn Icniitli (mm). — Males: 56.8 ± 2.2. 53- 61. 25. Females: 57.2 ± 2.1. 5.3-60. 15. /Vt/// U7(///; (mm).— Males: 13.5 ±0.8. 11-15. 25. Females: 12.5 ±0.8. 1 1-14. 15. Tarsus Inr^lh (mm). — Males: 67.8 ±3.1. 60- 72. 25. Females: 63.8 ± 2.5. 58-67. 15. Tail Icir^ih (arc. mm).— Males: 102 ± 5. 92- 1 10. 15. Females: 96 ± 7. 76-103. 12. MlASliRKMtiNTS (MM) Ol- EgCIS (,V =11) Lcn;^ih. — mean = 81.8. range 77-86. Width. — mean = 56.6. range 56-57. Briei- Di sckipiion The body is predominantly battleship gray in aspect with considerable chestnut on scapulars, sides, anil flanks: lower breast, belly, and most secondaries are white (Fig. 4). Central tail feathers are elongate and recurved. Males are larger and more robust than females. Bill color of adult males is bright yellow-orange: bill is largely orange in adult females, and darker in subadults and juve- niles of both sexes. There are three molls and plumages per cycle. the prebasic molt replacing the whole feather coat, the other molts replacing only the feathers of the head and neck. The deflnitive alternate plumage is sexually dichromatic: the deflnitive supplemental plimiage is also probably sexually dichromatic. Juvenal and basic plumages: head and neck (both sexes) tlark brown with a faint whitish postocular streak in the juvenal plumage. Deflnitive alternate plumage: male — gray crown, brown cheek, white postocular streak: fe- male— head and neck dark brown with white postocular streak. Deflnitive supplemental plumage: male — head and neck w hite (crown pale gray in some mdi\ idu- als) with small patch of chestnut on throat; fe- male— imknown. Class-I tlow ny differs from di)w nies ot all other Tcichycrcs in having the postocular streak undi- vided and the supraloral and supraocular patches narmw and continuous with the posiocular streak. DisrKimrioN Endemic to and abundant throughout the Falklanil Islands on marine coasts and nearby ponds: unfortunately, available records prov ide an inadequate representation of the disiiibulion and 30 UNIV. KANSAS MUS. NAT. HISI . MONOGRAPH NO. 8 breeding range ol llic species dig. 6). Tlie pres- ence of 7". hrachypicnis on tiie .lason Islands is likely but unconfirmed, bul tiie s|5ecies evidently does not inhabit Beauchene Island. Cawkell and Hamilton (1961:13) reported that individual birds have been observed three miles from shore. TaCHYEKES PTENERES (FoRSTER, 1844) M ACELLANIC FeKJHTLESS StEAMER-1)| ( K Oidcntiapiiiiichonicii. — King{ IS2S: 100); synony- mi/ed with Microptenis hrachyp/cnis {cunvnt\y segregated as T. pteneres) by King (1839:35. 542). Strickland ( 1 841 :39), Gibson ( 1 877: 1 36). and Stenhouse (1929:185; 1930:274). Kuroda ( 1 942:4 1 ) mistakenly stated that Gibson (1877) synonymi/.ed Oidcmia patachonica King uith Anas crislala Gmelin. As detailed by Herman <■/ al. (1990:13). Oidcmia patachouica was sup- pressed and placed on the Official Index of Rejected and Invalid Specific Names in Zool- ogy via Livezey ( 1 989b) and International Com- mission on Zoological Nomenclature (1991 ). *Mivnipivnis hrachyplcro. — King ( 1831: 15). Mivnipicnis liravliypUTiis. — liylon ( 1838: 144. in pan: 1869a: 101. in part); King (1839:542). Anas picncrcs. — Forster (1844:338). Micnipicriis cinercits. — Cox (1863:235. in part); Newton ( 1 870:504); Cunningham ( 1 87 1 a:493. in part); Giglioli ( 1 875:93.3-943.963); Oustalet (1891:212-216. 220-222. 224-226. 228-231. plate 4); Sclater (1892:173-174); Carbajal (1900:282); Agostini (1955:216). Tachycirs cincreiis. — Sclater ( 1881:107. m part); Sharpe (1881:13. in part): Holmberg ( 1 895:|22 1 1. in part ); Schalow ( 1 898:672-673 r Dabbene (1902:403-404. in part; 1910:233) Crawshay ( 1907: 1 10. in part): Nicoll ( 1908: 163 in part); Blaauw ( 19l2a:47-48: 19l2b:7 I M 16:488-492. plate XIV: 1917:275-276 1921:57-58): Sclater (1913:315); Mogen.sen (1917:85; 19.30:207); Anonymous (1920:77); Phillips (1925:134. 287-288. in part); Bennett ( 1926:327. in part); Snouckaert \on Schauberg (l926:l50-15l.inpart):Slresemann(l927:47. in part): Stenhouse (1929:185; 1930:274); Dabbene ( 1932:205-206); Reynolds ( 1932:35); Boubier ( 1934:85-86. in part). -52 Fig. 6. DclailcxI map of the disiribulioii of 7'. hiai hypicnis based on specimens, published records, and adequalcly documeiUetl. unpiibJisJK-d obscrvallons. Specimens arc shown as solid circles, sight records as open circles, and evidence ot breedim: (nests, broods) is indicaleil b\ iliaiional slashes. STEAMER-DUCKS (ANATIDAE: TACHYERES) 31 liulixcrcs h}\u hxptcrus^ — Hcllma>r ( 1432:335. 337): Lowe (1434:474-4X8. 440-443. in part; 143.5.424): RL-ynolds ( 1434:3.50-351: 1935:S4): Reynolds in Lowe ( 1434:470-472. 474-477. in part);Caslellanos( 1435:36): SieulletandDeauiier ( 1 435:36.5-367. in pail ): Zolta ( 1 435: 1 SO. in part; H)44:30. in part): Junge (1434:161. :n part); Reed (1434:34-35. in part); Belin (1442:121): Housse (1442:177; 1448:324); Pereyra (1443:227); Bairos V. (1445:200; 144S:52); Cailqiiist ( 1465:231-233. in part). Tdchycrcshnuhypteia. — Anonymous ( 1435:124). lachycrcs /J/c/zcrcv.— Murphy (1436:144. 453- 95S. 964-465. 468-464); Bulloek (1436: 1 37); Steullet and Deaulier (1436:367); Reed and Philippi B. (1438:13): Lauhmann (1440:14- 20); Anonymous ( 1442:310; 1450:44); Housse (1445:42); Trimble (1443:414); Delaeour and Mayr ( 1445:15. 38; 1444:40. 42. 63); Philippi B. (1445:144; 1464:47. in part ); Hellmayrand Conover (1448:374-376); Olrog (1448:473; 1450:518; 1454:70; 1463:100: 1468a;lll: 1468b:plate 11; 1474:500; 1484:42. 264; (he last live references evidently included both T ptciicics and T. Icucuvepluiliis): "^ahe/ (1448:153; 1444:8. 10); Goodall cl al (1451:162. 165. 167); Boetticher ( 1452:23. 68. 41): Pergolani de Costa (1453:36; 1470:35): Verheyen (1453a:384. 435; 1453b;463. 486- 487; 1455:2. 15; 1458:4); Delacour( 1454:270- 271. 274): Scott (1454:61: 1472:48); Philippi- B. Cl ill. (1454:24); Holgersen (1457:54); Moynihani 1458:183.201 ); Lysaght( 1454:284. 312); Van Tyne and Berger (1454:233: 1476:347); Wooltenden ( 1461 :4): Schonwetter (1460:132); Berndt and Meise (1462:142); Godoy (1463:31): Humphrey and Clark (1964:186); Bernath (1465:48); Johnsgard (1465:44; 1468:105; 1478:136. in part: 1474:452. in part); Johnson (1965:145): PettingilH 1465:71 i; Smith ( 1465:55): .lohansen ( 1466:23 1 ); Meyer de Schauensee ( 1466:40. in part; 1470:32. in part; 1482:32. in part); Stresemann and Slresemann ( 1 466:305 ); Ciew all (1468:188); Griswold (1968:32); Lack (1468:347: 1474:85); Schmidt (1464:125); Weller ( 1464:128; 1475h:86; 1475c:110; 1476:45): Humphrey ct al. (1470:124-137); Markham (1470:45. 48; 1471:22); Raiki)w (1470:570; 1485:82); Barros V. (1471:172); Bock (1973:208-204); .lehl (1473:124: 1475:546); Pisano V. (1473:42); Texera (1473:245-247): Vigil (1473:64, 71. in part); MacLean (1473:24; 1474:143); Merne ( 1474:34.79); Morony ctul. ( 1475; 12): Woods (1475:122): Brush (1476:482. 485): Gruson (1476:11); Jehl and Rumboll (1476:146); Kuhnemann ( 1 476; 1 57); Venegas C. ( 1 476: 1 77- 180. 183: 1481:216-217; 1486: 1 1 .61 ); Wolters ( 1476:48); Blake ( 1977:227. in part): Daskam (1477); Jacob (1977:52-58; 1482:87); Navas (1977:35-36); Navas and Bo ( 1977:74); Reed (1977:27): Sielfeld K. (1977:285. 294): Clements (1978:28); De la Pena (1978:58; 1986:80. in part); Soothill and Whitehead (1978:281); Boswall and Maclver (1979:75): Goodall (1979:76): Todd ( 1979: 160); Venegas C. and Jory H. (1979:72); Clark (1484:212- 213: 1486:100, in part); Howard and Moore (1980:71; 1984:71); Erize cl al. (1981:178); Gotch (1981:83): Humphrey and Thompson ( 1 98 1 : 1 . 3. 5-6. 10); Araya ( 1 982:5 ): Humphrey and Live/ey (1482a:l-2. 21-22; 1482b:368. 370-371: 1485:444-451); Jacob and Ziswili (1482:274. 276); Livezey and Htimphrey (1482:12-16; 1983:485-486; |984a:257; 1984b:368-373: 1985:154-155; 1986:540-549. 552. 556); Mli'kovsky (1982:728); Scherer and Hilsberg (1982:360); Carpi ( 1984: 1 16. in part): Daciuk and Heber (1984:174. m part); Kolbe ( 1484:66. 170-172); MendalU7(//.( 1984:306): Walters (1984:18); Edwards ( 1985:21 ); Araya M. ct lts and plumages per cycle, the prebasic limit replacing the whole feather coat. the prealternate molt replacing only the feathers of the head and neck. The definitive basic and alter- nate plumages are sexually dichromatic. The de- linilive basic plumages of the head and neck of neither sex resemble the juvenal plumage. Juvenal plumage of head and neck (both sexes) is medium to dark gray, lighter ventrally: there is a small patch of brownish chestnut on the throat. Definitive basic plumage: male — dark gray crown, light gray cheek, indistinct postociilar streak, small indistinct chestnut throat patch; fe- male— head and neck medium-dark gray, short faint postociilar streak, small indistinct patch ol chestnut on throat. Dehnitive alternate plumage: male — light gray crown, rest of head and neck pale gray to white with indistinct patch of pale cinnamon on throat; female — crown dark i:ra\. cheeks iiKHlium gray. short pale grav to \s hilish postociilar streak, chest- nut patch i)n throat. The class-! downy difleis Irom ilownies of all oilier Taclncrcs in having the |iostociilar streak divided, and the supraloral and supraocular patches are very small (and separate) or lacking entirely. DisrRiininoN Resident on marine coasts and islands from immediately north of Isla de Chilotf. Chile south to Tierra del Fuego. including Kla de los Estados. Argentina, where H. M. Cadot. Jr. (pers. coiiini.. 1971 ) found them to be the most common duck (Fig. 7). Olrog ( 1963:100) stated that the species ranges north to Concepcion. Chile, during winter, but confirmatory specimens are lacking. Olrog ( 194S:473) suggested that T picncrcs nested also on Lago Fagnano. a large inland freshwater lake on Isla Grande. Tierra del Fuego, but no documen- tary evidence was provided and Olrog deleted this idea from his subsequent works. Contrary to the statements of Olrog (1959, 1963. 1968. 1979. 19S4). Philippi-B. (1964:47). Smith (1965:55). Meyer de Schauensee (1966:40: 1970:33). Vigil ( 1973:69). Woods (1975:122). Blake ( 1977:227). De la PeiKK 1978:58: 1986:80; 1 987:40). Johnsgard ( 1978:137: 1979:452). Carpi (1984:117). Daciuk and Heber( 1984: 174). Clark ( 1986; 1 00). and Araya M. (7 (//. ( 19X6:61 ). there is no specimen to docu- ment that 7. picncrcs occurs, even during winter, on the Atlantic coast north of Rio Grande. Isla Grande. Tierra del Fuego. The idea that T picncrcs occurs on the Atlantic coast of Patagonia may represenl. in part, confusion (iii Chubiii) with llightless T Iciicdi cplhiliis or the reluctance of many T. paiac/uniicus to take llight. but it appears to have had its origin in the vague, partially incor- rect delimitation of its range given by Murphy (1936:199); "The distribution of Ihe mainland Flightless and Flying species lar:.^cl\ n'linulcs iliniii:;li(iui a range extending from I'uerto Deseado on the Atlantic, southward to Cape Horn.... The Fliizhtless species. ..IS nurnhilly abseiil Irom the whole eastern part of 1 ierra ilel Fuego and the .Atlantic coast of Patagonia. Most of the steamer ducks 111 these districts represent the Flying spe- cies lemphasis added]."' 34 UNIV. KANSAS MUS. NAT. HIST. MONOGRAPH NO. 8 Fig. 7. Detailed map of the distribution of/', piciwivs based on specimens, published records, and adequately documented, unpublished observations. Specimens are shown as solid circles, sight records as open circles: evidence ofbreedini; (nests. bro(Hls) is indicated bv diuiional slashes. STEAMER-DUCKS (ANATIDAE: TACHYERES) 35 TaCIIYIKES EEICOCEI'IIAEI S HUMPHRKY AND TH()MI•S()^ 1981 WhITK-HRADKI) FLKiHTI.KSS SiEAMKR-Dk K Taclncirs piciwns—0\wi (l^SM:?!); 1M63:1()(); 1968:111; 197'):5()(); IMS4:92. IM: in part, sec under T picncics): Meyer de Sehausensee ( 1966:40. in pari; l')7():.32.inpart); Vigil ( 1973:69. in pari); .lulinsgard (1978:136. in part): Carpi ( 1 984: 1 1 6. in part ): Daciuk and Heber ( 1 984: 1 74. in pari): Araya M. ct (/;».s7/ I'ato \apor iioi -palagc'inico. — Eri/e cl r cheek gray in some individuals, with small patch of cinnamon on throat: female — crow n gray, cheeks brown: long, uninterrupted, prominent while pi>stocular streak. Class-I dow ny differs from clow nies of all other liicliycrcs in having the supraloral ami supraocular patches v\ide and continuous with the wide postocular streak. DiSTRIlU TION I leiuiH epiialits is limiled in distribution to coastal Chnbui. .Argentina, from Peninsula Valdes south through the Bahi'a de Camarones and Bahi'a de Concepcion to the northernmost regions of the Colli) San Jorge (Fig. 8). Within this limiieil range, at least during the breeding season, this species is by far the most abundant species of Tcicliycirs: it may be that the \er\ similar /'. iniUic/ioiiicii.s oc- curs in this area only as a (non-breeding) straggler iluriim the breedinsz season, or durinii w inter. MOLTS AND PLUMAGES Hisioin OK Sum Gi-:ni-:rm. KnowlI'DG,!: oi^ AnAIII) Pll AlAlil s The early exploreis of soLilhenimosi South .America aiul (he I-alkland Islaiuls ikiring the I7tli and 1 8tli centuries w ere not liamed ornithologists. Nevertheless, they coiitribuleii a great deal to early understanding ol the distribution ami habits of steamer-ducks. Many of those who worked on steamer-ducks in the 19th ami early 20lh centu- ries— whether in the held or with museum speci- mens— were ornithologists by training or experi- ence, or. at lhe\er\ least, naliiialisis. riiereloie. it is useful to assess the state of know leilge of molts and plumages of waterfowl in the 19th and early 20th centuries and ln)w this might have intluenced the assumptions, preconceptions, and conclusions of ornithologists of the period about the molls and plumages of steamer-ducks. Newton (1895), in his classic Dicrioiiary of liinls. sialetl that knowledge of molts and plum- ages of a great many species of Furopean water- fowl w;is minierately advanced by the 19th cen- tuiv even though, as he pointed out ( 1895:595): "The literature relating to this branch of ornithology... I was] very small.'" Nevertheless there must have been considerable knowledge about the molts and plumages ol those species of luiropean waleiiowl that hail been huntetl for centuries for 37 ■42° 67°W S 66° 65° ^ 0064° 0 1/ 63° ARGENTINA PROVINCIA DE CHUBUT ATLANTIC OCEAN I — I — I — I — r 50 KM Gol f 0 San Jorge -46° Fisi. X, Dclailcd map ol the disinhution of T Icuccccplhiliis hascd on specimens, publislietl reeiirds, and adeqiiatelv iloennieiiled. unpublished observations. Specimens arc shown as sohd circles, photographs as heavy rings, and siglit records as open circles: evidence of breeding (nests, broods) is indicated by ihagoiial slashes. IciikI or sport. The llightless cotuiilion ot water- durinj; the nesting and moiling seasons v,'ere passed fowl during the sLiinmer following the nesiiiig in Hnglandiisearly as the 16th century (cf. Newton season was well know n as early as the 1 2th century I SM.Si.sy? ). Popular and scientific knowledge about and laws |irohihitiiig the hunting of waterfowl molts and plumages of many species ot European 38 UNIV. KANSAS ML'S. NAT. HIST. MONOGRAPH NO. K walcrl'ovvl duiiiiL; iIk- I ''ill (.ciiluiN uas consider- able, and it was known that nian\ species: ( 1 ) Are se\iiall> dichronialic: (2) Exhibit seasonal dilterences in appearance, \ i/,. males of sexually dichromatic species have a bright plumage worn nn)st ot the year and assume a brief, dull eclipse plumage dining the llightless period t'ollowing the breeding season: (3) Take two or three years before attaining adult (definitive) plumage: and (4). Have male 'eclipse" (basic) and teniale plumages that are similar to or identical to the Juvenal plumage. The controversy thai most affecteti early under- standing of molts and plumages in Tachyevcs was the debate concerning recognition of one or two species of steamer-duck. Most workers on steamer- ducks during the IMth and early 20th centuries were preoccupied with this taxonomic problem and not with interpretation of molts and plumages per sc. In addition, most of them knew little or nothing about the molts anti plumages of waler- fov\l and ignored the subject except insofar as descriptive data concerning plumage aspects ap- peared relevant to the taxonomic question. There were, however, a lew workers (e.g.. Oustalet. Blaauw. I'liillips. Chapman, Lowe. Murphy) who presumably were knowledgeable about the molts antl plumages of European and other northern-hemisphere waterfow 1. Their inter- pretations of the molts and plumages of steamer- ducks, however, either did not take this knowledge into account or were based on certain preconcep- tions concerning southern-hemisphere waterfov\ I. Because sexual dichromatism is weak or lacking in several southern-hemisphere species, these workers inay have assumed that all southern-hemi- sphere waterfowl had only a single molt and one sexually monochromatic plumage per year. These workers, too. were preoccupied w ilh the problem- atic taxonomy of steamer-ducks. Even with good series ol' specimens of known age. a resource not available to ornithologists in the 19th and early 2()th centuries, understanding the variation in plumage pattern of an\ species of waterfowl is diflicult. lurthermore. until re\ iew of the genus b\ Murphy ( 19.^6). the whole prob- lem was confoundetl bv substantial taxonomic uncertainties. In what follows, we examine the growth ot know ledge anil interpretation ol |iluni- ages and solt parts of steamer-ducks in three eras: (1) Era of Exploration. (2) Era of Taxonomic Controversy, and (3) Era of Murphy. Er.a of Expi oRvnoN From the 16th into the 19ih century, steamer- ducks were treated as a single species and descrip- tions of their plumages were typological. Three important points characterized this period: ( 1 ) descriptions of steamer-duck plumages v\ere not associated with an\ taxonomic controversy: (2) steamer-ducks were universally understood to be llightless: and (3) it apparently did not occur to any of these early workers that sieamer-ducks might have more than one plumage a year. The explorers and naturalists of this period variously observed and collected specimens of steamer-ducks in the Magellanic region of south- ernmost South America and the Falkland Islands, and the cabinet naturalists of the day examined specimens collected in these regions and took account of the notes made hy the collectors. Al- though some of the resulting descriptions of steamer-ducks were more detailed than others, all of them captured the essential generic features of a steamer-duck, namely that they were large, gray thicks w ith underparts and secondaries white, and \ellow or orange bill and feet. Some accounts mentioned the orange wing-spurs (Forster 1777). ami iris color as red brown (Forster 1777) or orange (Latham I 7S5). The description hy Forster ( IS44i of the plum- age pattern ol Tucliycrc.s lAiuisi pteneres was an exceedingis detailed account that, in its careful- ness and attention to detail, w as a century ahead of its time. His account of the structure and colora- tion of the bill and feet was exceptionally thor- ough. In addition. Forster described the white on the secoiuiaries in great detail on a feather by leather basis, and he was the lirst to have noted that the lower breast, abdomen, and under tail coverts are yellowish- white (ochroleuca). an evanescent color not preserved in museum specimens. Forster also was exceptional because he specified the sexes of the specimens he described. He characterized STEAMER-DUCKS (ANAIIDAE: TACHYHHhS} 39 lliL" hoaci ol the male as lulcsccnti-alhiiin willi tin.' eye icgiDii wliilc and llic upper neck silk\ while (sericeo-alhus): he stated that the head and neck ol the female are cinereous and the eye region is while. Other descriptions of the plumage and soft parts of steanier-ducks by early explorers and naturalists were few in number aiul t\pically not sex-specilic (e.g., Forster 1777. Latham 17X5. Bonnaterre 1 790. Buffon 1 S 1 2. Quoy and Ciaimard 1X24. Knig IS2X). Quoy and Gamiard ( 1X24) vis- ited the Falkland Islands in February. March, and April, and their account was the only one that mentioned red on the throat and bieasi; their de- scription e\idently concerned '/'. hrachypicrii.s. which, although indistinguishable from /'. putiU lu'iiu lis in color pattern, was the species most frequently encountered in the coastal w aters of the Falkland Islands. None of the early explorers and naturalists mentioned downs \oung steamer- ducks and |u\eniles. and none indicated any differ- ences between the sexes in soft part colors. Era Ol- Taxonomic Controvkrsv Accounts of the molls and plumages of steamer- ducks from the early IMlh century until 1436 in- cluded considerable new information about de- finitive. immature, and downy plumages, sexual dimorphism, and interspecitic differences in plum- age coloration and pattern of adults. Although a greal man\ specimens of steamer-ducks were col- lected during this era and many descriptions of their plumages were detailed, the consensus con- tmued to be that steamer-ducks had hut a single plumage per year. Interest in the taxonomic issue led several natu- ralists of the time to characterize phenotypic dif- ferences more enthusiasticall) than they might have otherwise. Because T. initiuiioiiiiiis and /'. Ivin lixph'i us are virtually indistinguishable in the held and diflicult to tell apart as skin specimens, ourdisciission here will focus primarily on findings related to the continent, i.e.. comparisons of / /)) wrote that "...Younger individuals (M. FdliU hdiiu us) are chietly dislmguished by. ..their greenish-black bills...." Cunningham, of course, believed that there was but a single species of steamer-duck of v\hich \ounger iiulis itiuals (called by other authors patui iiauu us) were capable of flight. Oustalet ( 1X91 1 observeil \w differences in bill color between male and female T. paliuiunmus; he noted only that in 7". pakicluuilciis the colora- tion of the beak is generally less li\ely and more uniform than in /'. plcncrcs. Although Oustalet ( I X9 1 ) presented six comparative statements con- cerning the differences between 7. ptowics and T. piiiacluuiicus (using older generic and specihc names ). Blaauw ( 1 9 1 2. 1 9 1 6. 1 92 1 ) w as the Hrst to succinctly compare adults of T. plcncrcs (his t iiu'irus ) and 7". patacluniicus and describe sexual dimoiphism in the two species. ¥oxT. patch lu uncus. Blaauw ( 19l2a:47— IX) wrote that "...both sexes are much smaller than the preceding one \T. picucrcs] and the female is miich smaller than the male. The /t'/»t//c' is also coloured quite differently. 1"he male. ..is clear grey with a white breast and clear yellow bill. ...The female is much smaller than the male. The head is brown and the rest of the body of d beautiful wine colour w iih \\ hile breast." Blaauw (1916:491) noted later that the female "...is of a beautiful dark wine-colour, with grey centres to the feathers of the upperside and sides. The bill. ..IS brown or black." He ( 1916:491 ) also stated that "...A pair [T. patacltc»iicus\ invariably consisted of a large clear grey birti with a ncIIow bill, ami a much smaller brown one w ithdark bill." Scott and Sharpe ( 1912:492) recogm/ed only one species of Taclixcrcs and considered T. paiachnnicus the immature of the tlightless spe- cies (7, plcncrcs) "...which seems not lo attain full 40 UNIV. KANSAS MUS. NAT HIS I MONOGRAPH NO. 8 adult plumage until at least the second and perhaps the third year of its lile: moreover, the first breed- ing is probably accomplished in the phase ot'plum- age called by Dr. Oustalet M. putachoiiiiiis." Scott and Sharpe provided a detailed description ol a male specimen, now in the collections ot the Field Museum of Natural History, which was collectetl at the mouth of the Rio Negro in February I S')S. Based on our examination of this specimen, the bird was undergoing prebasic molt and the rem- iges had not attained their full growth. Scott and Sharpe (1912) described the colors of the soft parts as follows: "Bill: Horn-color, shaded with blue and green, the nail abruptly black. ...The feet and legs are dull greenish brown, strongly shaded with orange." This description and that of the feather coat indi- cate that this specimen was molting into dehnitive basic plumage. Although predicated on a mistaken concept of phylogenetic relationships. Scott and Sharpe (1912:492) insightfully commented that: "The change of color to orange or cadmium-yellow in the breeding season is to be looked for, as similar changes in the colors of the bill occur in other allied sea-ducks." As far as we can tell, this is the lirst recognition of the fact that colors of the bill and feet in detinitive male /. paunhonicus become duller during the prebasic molt. Phillips (I92.'i) was aware of the problematic taxonomy of steamer-ducks and divided his de- scriptions ot adult birds into those pertaining to three "phases" conesporuling to the three species to be recognized later by Murphy ( 1936). Phillips (1925:2SS) described adult red-phase specimens {Tachycrcs paraclianiciis) as follows: "Many of these birds (I have studied some forty-three speci- mens) do not suggest youth. They are mostly uniform in coloring, with adult tail-feathers, and in many cases the carpal spur is well developed. There are no apiiarent se\ ilitfereiices....Bill. in life yellow isli above, aiul bluish or greenish below nostril, nail black. In dried skins nearl\ always dark lead-colorall o\erculmen. sometimes slighil\ yellowish towards base, but never yellow all over as in Tciiliycrcs ciiicivus....\.ciis and feet yellow- ish, very nearl\. if not tiuite the s.inie as in Tth li\crr.\ cincrciis." liecause Philliiis noted no sevual tlillei- ences. we judge that most of the males in his series of specimens must Iki\ e been in basic plumage. Chapman ( l933:.Vil ) noted that "On January 24. 1^)24. on a iresh water pond in northern Tierra del Fuego. 1 saw a pair of adult Quettros (the male w ith the head and neck white i accompanied by one young about a week okl. both of which adults, when Hushed, took wing easily and flew out of sight toward the sea." This is probably the first description of a male T. patdi Ixmii iis in supple- mental plumage. Characteristics of 7'. picucrcs Cunningham (ISTIb:^,^) described the plum- age of 7'. j)!cncrcs. w hicii he considered to be the adults of a single species of steamer-duck, as "...The bill is orange-yellow, with the unguis black. The head is cinereous, becoming gradually paler as the individual increases in age, with a small patch beneath the eye, and a streak above it. nearly white. The whole of the upper surface, the throat, the superior part of the breast, with the exception of a white speculum, are lead-gray. The lower part ol tlie breast and abdomen vary from a lint \erging on primrose-yellow to pale yellowish-while: and the legs and feet are dark yellow ."This description is notable because: ( 1 1 Cunningham apparently did not consider the species to be sexually dichro- matic: (2) he attributed variation in color of the head to \ ariations in the ages of adult birds: and (3) he noticed the evanescent \ellow bloom on the lower breast and bell\. Oustalet (ISMI) examined ten specimens of w hat he called Micmptenis cinereiis. all of which, from their localities, were T. ptencrcs. These speci- mens were descrilied as having gray to bluish gray heads and that the rest of the body except for the lower breast and bellv was gra>. paler on the sides and Hanks, and darker on the back, and without an\ trace ol red. Bills of both sexes were yellow- orange with nail black. Comparing 7'. picucrcs w ith 7. patiuhoniciis. Oustalet noted that the fun- damental colors of the plumage of the adult are the same. He considered the colors of T. ptencrcs as generallv less distinct than in T. paluclioniciis and that the gra\ color ol the plumage of T. picucrcs is not as dark as in / patm honiciis and the feathers of the back, breast, and flanks lack the scaly ap- pearance I ound in I jhiiiK linnic us. I'i nails, Oustalet STFAMER-DUC-KS (ANATIDAE: TACHYERES) 41 notcti llial the reil iir reddish tiiu ol Ihc ihioiil anil some tletail. iiicludnig colurs ul bdl and Iccl. hut bivasi nT /,/ii//(/<7/(i/;;( ;/.s isahnosl al\\a>s lacking lUilL'd (p. M5) of Ihe female i)iil\ llial il was in 7'. piciwrcs. ■"Similar Ui the male, hiil somevv hat smaller." Nicoll Snbseqnent deseripiions h\ Salvadori ( IS')5). ( |M()4) and Evans ( I9(W) described both sexes of Nicoll (l')()4i. Blaanw (im2, 1416. 1421). /. /vc/zc/cv (under V. (7/(c/f/(.v) as having orange or Mogensen ( 1917). and Phillips! 1925) provideil in orange-yellow bill and feet, respeclively. varying detail the same descriptive information as Blaanw (1412, 1416. 1421) was the lirst to did Cunningham ( 1871 ) and Oustalet ( 1S41 ). indicate details of sexual dichromalism in 7'. I'icncrcs. noting ( 1421:57) diat "...both sexes are Sexual Differences of Adult T. paUhhi'iiinis giay: the male has a pale or pearl-gray head and neck, and a bright yellow bill. In the female the gray is duller, so that the head is not strikingly iialer than the rest ol the bodv. The bill is also Cunnineham (1871b) did not remark upon the ,, , , 'i •• n i i . ' vellow but not so clear in color. He did not sexual dichromatism of 7. /'(//<;(7(r;/(/(7/,v. Oustalet ' ,.,,.. ■ u .. ' . mention anv difference in si/e between Ihe sexes. ( 1841 ) presented descriptions of SIX specimens ot .. ' ,,,,-,, ■, , , •,• ' . . ' 111 Mogensen ( 141 7) described male /./'fcHC/Y.va.s Presumabl\ because of the small amount of material available to them. Kiiii; ( 18.^1 . I 834) anil T. pdidcliiinic us including one adult female and bemg somewhat lighter than the female especially one adult male. Althouszh his descriptions indicate ,~i i i i"i lur ' on Ihe head, but did not mention anv differences in that the beak ol the temale was black becomin>; greenish-brown at the base of the upper mandible and that of Ihe male was light orange-yellow, he made no note about sexual dichromatism in the species. The sexual dichromatism ol adult 7'. pahu lioiiii us was clearly described by several authors (Blaauw 1912. 1416. 1921; Mogensen 1417; Lowe 1434). Blaauw ( 1916:491 ) noted that: Juvenal Plumage of 7. pataclunmus ".\ pair iii\;iriabl\ consisted of a larue clear iirev , . , ... I, ■ , .., , 1 " II u " There was no mention ot the juNenal plumaae bird with a yellow bill, and a much smaller brown ' c , " bill color. Phillips (1925:288) noted of adult te- male 7. ptc'iu'ix's: "Size somewhat smaller; color same as in male... .Bill yellow or yellowish but not such a clear or brilliant yellow as in the male." Lowe( 1934) stated that the adult feiiKile has '■head and neck iirev. not much ilarker than." one with a dark hill." Blaauw ( 192 1 :58) described the sexual dichromatism of ;idult /'. patdchoincus as follows: "The male is clear erav with a white , , , I 11 , I, Vi ' I- 1 I "vounti" specimens which he identified as T. breast and a clear vellow bill. ...The temale has a • ^ ^ ol steamer-ducks until the statement by Sclater (1881:108) that "In all the immature birds the bill is uniform black." Oustalet ( 1891 ) described two brown he;iil. and the rest of the body is of a beautiful vinac bill is brown." pdidi luiiiiciis. One of these, for which sex was not , . .■ , , ,, I , u' , 11 ttiven. had the plumaae mixed with tufts of down beautiful vinaceous color, with a white breast. I lie ^ *^ ^ on the back and on the wings but still show ing the principal colors of the adult plumage and the red tince of the sides of the head and breast. The other Sexual Differences ot Adult 7. /'?(7;c;c.v " . u- u u i . ■ i. u e i i ' specimen, which he determined to be temale and Most early descriptions of plumage pattern and younger than the first, was collected on 9 February soft part colors of T. ptenercs did not address 1 883. The specimen had dark gray plumage with sexual dichromatism ( Des Murs 1847, Cunningham blackish brown on the borders of the feathers, the I 87 lb). Oustalet ( 1891 ) examined ten specimens head was uniform gray without a while streak in of 7. plena cs. hve of w hich were determined to be the vicinitv of the eye. and there w ;is no white band temales and one a male. He described both sexes on the w mg; the last obsers alion indicates tluil the asha\ ing yellow oryellow-orange bills with black growing Juvenal remiges were still quite short, tips and feet yellow or yellow-orange variably Lowe ( 1 434:476) stated that "When able to fly. mollled w iili gray. and lor some time afterwards, young T. Sahadori (1845) described an adult male in piihu Iidiiu us of both sexes are scarceK ilisiin- 42 UNIV. KANSAS MUS. NAT. HIST. MONOCKAPII NO. 8 guishablc liDm ihc aclull Icmalcs. In the inimaliirc. however, the transocular stripe, although appar- ently longer, lacks sharp contrast with the contigu- ous plumage and is not clearly defined." Evidently the "immature" plumage referred to by Lowe en- compassed the post-Juvenal, pre-detinitive plum- ages of the head and neck. Juvenal Plumage of T. picncrcs Nicoll ( 1M()4) collected in southern Chile west of the Straits of Magellan three specimens of what surely must have been I', ptcncics (the adult male and female both had orange bills). One of the specimens was a Juvenile with dark brown bill and feet. Blaaiiw ( 1921:.57) noted that ■'In the young birds |of 7". /)/('/;(';£'.s|...the plumage is tinged in some parts with brownish gray, but not enough to obscure the generally gray aspect. The bill color of such young birds is mi.xed with a dark greenish tint, and their legs are dark. These birds were evidently young of the year, since they were under the guidance of a pair of adults." r^hillips ( U)25:2S8) stated that: "We know that there are individuals which do not pass through any red or reddish-tinted phase. Whether these are exclusively the young of the gray phase C/i/r/nc/r.v cincrciis) we do not know. A specimen in ju venal plumage from Cape Horn with the primaries not yet fully developed. ..is gray all over the upper side and without the prominent wine-colored edges to the feathers on the breast, sides, and Hanks. Abdo- men white as in the adult; whole head and neck gray with some lust color on the cheeks and lower side of neck, but not nearly so dark or so ruddy as in most examples of the red phase Crachycics pcitaclutnii ii\). In other words, this young bird does not look as though he were going to pass through the e.xtreme dark and ruddy phase...." I Ic noted further (p. 288) that the bill in this specimen was "probably ilark greenish on the culmen and lighter below. Legs and feel yellow. ..tarsus (1.^ (rather large for the red type). " Downy Young of 7". pciuuhoniviis Oustalet ( \W\ ) evidently had obtained speci- mens ot downies of both T. pahuhoiiiiiis and T ptcncics but appaicnily was unaware ol the tli- agnostic features of the patterns of the head, and it is not clear how he identified his specimens of downy steamer-ducks. Oustalet ( 1891 i described a downy steamer-duck which he identified as 7'. pataclioniciis but his description could pertain to either 7. paicnlKiiiiiiis or T. ptcncics. The bird was a very young female (chick) still in down brought in alive by the Luegians at Orange Bay on 1 1 Februarv 1 88.^. The iris was light brown: the beak was black, becoming reddish on the posterior up- per manilible and light horn at the tip, which still had the egg tooth. The membrane between the lower mandibles was yellowish; the tarsi were dark greenish olive becoming blackish: the down already showed the distribution of colors of the plumage of the adult, notably the white streaks on the sides of the head behind the eyes. Oustalet described two other downies, collected on 10 February 1 88.^. which he had identihed as T. ciiicicus which, from his description, possibly were /'. pataclioniciis. The specimens had beak and feet blackish, head and body covered with down but alreatiy showing the dominant colors of the plumage ol the ailult. ami a large w hite super- ciliary streak extended a little posteriori) along the neck. He described yet another dow n\. a \ery young I'emale brought in ali\e b\ the Fuegians on 26 January 1 88.^ which was identified as t. cincrcii.s (but which also probably was 7'. patuchonicu.s). The head and hocl\ were eniirel\ coveieil with down which was brown abo\e with white on the chin and abdomen, above and behind the eyes, and on the sitles ol the neck w here there was a large recurved band joining the light ct)lor of the chin. Two even younger females were brought in alive by the Fuegians on 12 Januar\ 188.v Here again. Oustalet idenlilied them as 7. cincrcus but. from his description. the\ probably wcvcT. pataclioniciis because the\ each had a wide, while posiocular streak. Lowe ( I'J.M) was the lirsl to present an absc)- lulely diagnostic description of the downv \(iung of T. pataclioniciis. He (p. 481) described the ".Supraorbital stripe and posiocular patches" as being "White, broad, more diffuse and continuous (low n sides of neck. In two chicks a few days old the jxilches w ere separated b\ a very narrow line of brow n." .STEAMER-DL'CKS ( ANAT1I5AE: TACfDTRES) 43 Do\ui\ ^DLinj: dI I\ pivnvn's Cuiiniiighani (IX7lh:47) dcsL'ribcd a dcnvny young, cicarh thai ol /, phiicrcs. as tbilows: "...llic entire uppei" Mirtace ol the body, the sides of the head, and a jnngel around tlie lower part of the neek. were eo\ered with a yreN ish-black down. while the under surface and a spot placed ob- liquelv abo\e and behind the eye were white." Oustalet (IX') I) stated that he could identif\ with certainty as M. cincreiis (i.e.. 7' picncics) a number of \'oung individuals. Based on his text, it is clcai that his certainl\ was misplaced since the patterns he described for the heads ol these dow nies all pertained lo T. pafcn ho/iiciis except for one young male killed on (i l-ebruar\' I8S3. The last specimen had the head and body still covered m large part by down. The upper parts were brown, the breast brow nish gra\. the bell\ white, the sides of the head brownish gra_\ with a very liglith marked postocular streak, wings reduced stumps but showing a small while transverse band. The beak and feet were blackish brown with some yellowish spots on the sides of the toes. Salvadori ( I Sy.S:.^?.^) describetl downy young steamer-ducks as ha\ing; "Head. neck, breast, upper parts, sides, and Hanks dusk\ gray; abdo- men and underiail coverts white; two white spots on the sides of the head, one behind the e\e on the temporal region, and another lower diiwn behind the ear-coverts ...." From his description, the downy young in question was without question a speci- men of T. picnercs. Scott and Sharpe ( l'-M2;442) described young birds in dow n as having "...head, breast and upper parts, as well as the sides and flanks, dull slaty gray, with a brownish tone; the abdomen and under parts and two spots on the head behind the eye on either side are white or cream> white." The specimens examined by Scott ami Sharpe clearl\ pertained lo /. piencrcs. Blaauw (1416) described the downy of T pwncirs but his description was not diagnostic for the species. Phillips ( U)2.'i:2X'-M described downy young Tcniivcrcs as ha\ ing "lores and cheeks light buffv brown shading lo almost white on sides of neck, while abo\e. behind, and below the eye are indetinite whitish streaks t(trming. with a slightlv darker streak between the bill and eye. a definite ■face pattern.' " llie tlowmes Phillips described wereclearlx those of /'/'/(•;«■;■(' .v. Lowe( 1934) was the Hrst to compare unequivocally identihed. pre- halching embryos; he stated (p. 4S I ) that downy T picnercs had "No supraorbital stripe, postocular patches white, not so broad or so diffuse, and interrupted by a conspicuous belt of the general dark coloration ot the crown." Ornithologists during the era of taxonomic con- troversy made several significant contributions to knowledge of the plumages of Fuego-Patagonian steamer-ducks. These included description of the differences between adults of 7. pakichnnicii.s and / , ptciicrcs by several authors, regardless of w hether ihe\ considered them one or two species. In addi- tion, several authors described the sexual dichromalism of T pitUicluiun us and the relative lack i>f it in y. picnercs. Finally. Lowe (1934) contributed substantially to the later taxonomic resolution by Murphy (1936) b\. anmng other things, definitively describing the differences in the head patterns of downy young T. patachonivus and /. picnercs. Era of Mlirph'i- This era started with the publication of the classic twci-volume work Oceanic Birds of Smith Anicruii b\ Murph\ (1936). which included a landmark analysis of the taxonomy of steamer- ducks. In addition to bringing the era of taxonomic conirosersy about steamer-ducks to a close. Murphy presented detailed descriptions of adult and downy plumages of three species of Tachye res based on an examination of a large series of speci- mens and a synthesis of published and unpub- lished information concerning the natural history of each of the species. Subsequent ornithological works were characterized by acceptance of the conclusions presented by Murphy ( 1936) concern- ing the taxonomy, plumages, and thsiributions ot steamer-ducks. A number of problems remained, however, and several of his conclusions (some incorrect) profoundl\ mtluenced later WDrkers. Number of Molts per C\'cle Murphy ( 1936:941 i wrote thai "Males of no South .American duck lia\c an eclipse plumage which is so characteristic amonii northern-hemi- 44 UNIV. KANSAS MUS. NAT. HIST. MONOGRAPH NO. S splicic species." .AltliDuyli the ikuiiil- oI the so- called "eclip-se" plumage was not understoDtl at the time of his writing, a likely implication of this passage is that linlixcrc, have but one molt per year. Johnsgard ( I '■Ht2: 1 46) listed Tachycrcs as not having an "Eclipse plumage present in males..." hut listed the genus as having "Two molts of body leathers per year." Weller (I96S:2()6) observed that "Most southern-hemisphere ducks have plum- age cycles which differ from northern forms by the absence of the "eclipse" plumage. ...Some species lack sexual dimorphism, others have sexual di- morphism all year, and some possess the first non- nuptial (basic) plumage strongly developed." It is not clear from this passage whether Weller be- lieved that most southern-hemisphere ducks have but one molt and plumage per cycle. Nevertheless, with respect to Tuvhyeies. Weller (1976) con- cluded that variation in patterns of the head and neck of male steamer-ducks is a function of age rather than the result of different plumages in a gi\en cycle, clearly implying that steamer-ducks have but one plumage and molt per c\cle. Intraspecific Variation Attributed to Age Cunningham ( lS71b:95) noted for the ""adult" steamer-duck that "The head is cinereous, becom- ing grailiiall\ palei as ilie individual increases in age...." .Although Murphy ( IQ36:9.'i7) did not e\- plicitls state this principle of variation v\itli age, he noted of the retldish spot on the throat o\T. piriicirs thai ■■...Fletlgluiys and voung adults. ..show less of n than thoroughly mature birds." L)elacour( 19.S4) also acknowledged age-related, seasonal, and in- di\idiial \ariation in I piciiercs. Woods (197.^:1 IS), in his description ol / hnu Inptcnis. staled that "Old males liaxe an al- most completely u hite head, \\ hile vounger males have a grey heail with white rt)iind the e\e continu- ing 111 a cur\ e dov\ n the side of the neck...l-roni the second year, an immature male grailually gams more grey on the heail and more orange on the bill." Weller (I976:47i staleil that: ""In I-l>ing Steamer Ducks and l-alklaiui l-lighlless Steamer Ducks, mature males are u hue headed...." lie also slateti (p. 49) that '"On the basis ot plumage coloui and behaviour ot I alkland island hinls, I suspect that there are at least four age classes: yearlings in large Hocks, birds two years or older in smaller groups or roving pairs, still older non-breeding birds u ith some white on the head of males resi- dent on suboptimal territories, and white-headed males that are successful breeders. I have too few observations to Judge whether this pattern also is true of Flying Steamer Ducks, but \ariation in head and bill color of males suggests this possibil- ity."" Weller ( 1976:46) also noted that adult males of the Flying Steamer-Duck and Falkland Island Flightless Steamer-Duck have the head: ""Whitish; younger males with greyish or brownish face: white eye stripe." For the Magellanic Flightless Steamer-Duck, he stated (p. 46) that the head of the adult male is: ""Uniform gray: whitish crow n in older males. ■■ Navas ( 1977) noted of 7". pahichoniciis that the oldest males are less rusty in general and ha\ e the head and neck lighter gras or partialis or totally white. Johnsgard (1978:138) stated of T. hracliyptcnis that "Adult males have a head that is predominanll) gra\ ami white (nearl\ pure white in old males)...." Curiously, the only authors to attribute intraspecific variation in head coloration of males to season are Chileans. Goodall et al. (19.^1) noted of 7". puitii liomciis that the male during certain seasons of the \ ear has a v\ hite head. The\ noletl also lor 7. /'?<7/crc,\ iluii the color ol the head \aries a great deal b\ season being at times ctmipletely whitish. Araya and Holman (I9S6) noted of 7, pdUn licnii ii.\ that the male nia\ ha\e a white head in certain seasons ot the \ear. Mo\{ of Reniiges \Iur|ih_\ (1936:M61) wrote that ""Most of the atiulls 1 7'. pienvics] taken b\ Beck at Chiloe in Ma\ v\ere in worn and molting plumage....ln these and other examples some of the remiges had be- come frayeil practically ilow n to the shall as a result ol their lrec|uent battering against the water. .Among most such binls the two outer-most prima- ries were new. the inner ones at the |ioint ol being shed in sequence." In his discussion about T. pulai honiciis. Murphy ( 1936:971 ) noted that "".At I ishuaia on .April 1 ...ailults in the \ icinit\ had lost most of their rectrices. while the lemiues were in STEAMER-DUCKS (ANATIDAE: TACHYERES) 45 ihc nmKi ol nioull. oki wiirii primaries staiulmy m juMapoMluiii w ith fresh imes." In eiintrasl, Slreseniann and Stresemann ( 1466) found lliat in all three speeies of Tachycics the primaries are shed smiidianeinisly. Of all the speci- mens (if Tdchyercs we have examined in wing nidit. we have seen only one individual, periiaps diseased, in which the remiges were not hemg replaced simultaneously {T. hnichypleius. male, collected on Lively Island. 12 February l'-)84; KLI 8052 1 ). Simultaneous replacement of the remiges is the rule in the family Anatidae; however, the Ruddy-headed Sheldgeese {Chl«cpha;^a nihidi- ccps) in Chile and Argentina typically undergo sequential replacement of the remiges (Summers I4S2). Other cases of non-simultaneous replace- menl such as the one T. hrachyptcriis we exammed must be considered anomalous. leathers whatsoever. Later in March the soung bird began to deselop contoLU leathers and by 1 .^pril its head. neck, upper back, sides and Hanks were completely covered with Juvenal feathers; there was still considerable down on the lower back. By I April the primary remiges were c|uite long but it cannot be determined whether they were fully grown. This record indicates that the young T. ptcncres. reportedly well fed. remained "downy" for two months after hatching, did not start to develop contour feathers until it was more than two months old. and that the remiges prob- ably were not fully grown until the bird was about three months of age. This inference contrasts with that for most North .American ducks, in which age at hrst flight varies from 37 to 77 days and for most species it is less than two months ( Pettingill 1 970). Development of Fledglings Murphy ( l'-).i6:y71 ) stated that "Fledglings ol the flying species, no less than those of the flightless. acquire their wing quills very slowly, so that they only have barely sprouted primaries for a consid- erable period after the down has entirely disajv peared. Three of the flying species in this stage were taken at L'shuaia on April I." Soolhill and Whitehead (iy7S:2S()). writing about T. paiaclioiiii IIS. stated that "The fledglings, just like those of the flightless species, acquire their wing quills very slowly. Even when the down hasdi.sap- peared entirely, there is a considerable period of time during w hich the primaries have only barely sprouted." From the way in which this was stated, we suspect that Soothill and Whitehead rephrased the statement by Murphy ( 1 936) and that their com- ments were not based on original observations, Llnpublished notes by Abby Goodall (pers. comm.. January 1 98 1 ) concerning the early devel- opment of a downy T. plcnercs hatched from an egg found at Harberton corroborate the idea that fledgling steamer-ducks acquire their remiges ver\ slowly. Dated photographs of this bird, which hatched on 5 .lanuary 1977. during the ensuing weeks sht)w that from .5 January to 5 March the young steamer-duck continued to be completely covered w ith down and had developeil no contour Resemblance of First-year Males to Adult Females Lowe (1934:476) was the lirst to note that "...young r./i(/r(;(7;<»«;(:H,v of both sexes are scarcely distinguishable from the adult females." Murphy (l'-)36:464) noted for T. hracliyptcnis that: "lounger males exactly resemble females.,.." Murph\ also stated (p. 968) for T. puhu lunik us that: "Younger males resemble females in the extension of reddish coloration to the sides of the head or even to the forehead and crown. The color of their bills also resembles that of females." Delacour ( 1954) also noted that young males re- semble females in both 7' patch Iuhih us and T. hiiicliyplcius. Several other authors (Navas 1M77. Johnsgard l'-)78. Soothill and Whitehead I '■178) noted that immature males of T. patachoiiicus resemble the female. Navas (1977) observed that immatures resemble females, as do the youngest adult males. Johnsgard (1978:138). in his description of T. hiiulixptcrus, wrote that ".luvciiilcs and Hrst-year birds resemble females but usually lack the white streak behind the eyes, and second-year males gradually acquire a grayish head and orange bill." Woods (1982:49). also writing about T. hracliyptcnis. stated that "First year birds resemble the female but usualh lack the white head streak." 46 UNIV. KANSAS MUS. NAT. HIST. MONCXiRAPH NO. 8 Ciokk'ii ("ollai III /, hidi Inptenis Murpin ( l'-).Vi:M.^.>lsialC(llliat '".An unique cliar- aclcr ol' 7. hicu Inpicnis is llic more or less distincl ring of glossv golden lealliers around the neck. It i.s usually evident in females to a greater e.xteni than ni males, hut no okl I-'alkland hirtls seem to he without a traee ot it." In hi.s description of 7. hraclivplcni.s. Murphy (p.'')64) wenton to say that, in the adult male, "...neck with a distinct silken yellowish or golden sheen never present in plcncrcs...." He (pp. 964-M65) also stated of adult lemales "...base of neck showing a glossy, golden yellow ring, somewhat indetinite in extent, but more pronounced than the same feature in males, and peculiar to this species...." Subsequent to Murphy, the descriptions of T. hi\uli\p!cnis by several authors (Delacour l'-).'S4, Olrog 19.^9, Pettingill 196.^, Johnsgard 197S. Soothill and Whitehead 1978) mentioned the "golden collar." Johnsgaid ( 1978;L^S) slated that "//( ilic jicUI. this species can be separated from the flying steamer-duck b\...a golden-yellow ish collar at the base of the neck." .Soothill and Whitehead ( 197(S:2(S1 ) wrote concerning T. hia< liyptcnis that males have "...more yellow around the neck than T. ptcnercs" and noted of the female that "...the yellow neck collar more pronounced." We are pu//led by the alleged "golden collar" of Falkland f-lightless Steamer-Ducks. We have examined the series of skin specimens o\ this species available to Murph\ at the American Mu- seum of Natural Histor\ aiul have observed hun- ilreds of iiuli\ iduals of this species at close range in the Falkland Islands, including examination of st)me 20 freshly collected specimens of atlults and subadults of both sexes, without ha\ ing tliscerned a pronounced golden yelk)w collar in either sex of adults. It is noteworthy that several authors (Cawkell and Hamilton 1 ')(> 1 ; Woods 197.^, 19X2; Weller 1976), lamiliar wiih lalklaiul Flightless Steamer-Ducks in the lieki, have not included the "golden collar" in theirdescriptions ol the species. COMMKNTS ON DkSCRII'HONS Our stuilies ol ihc plumages and molts of steamer-ilLicks and our protocols lor collecting data on molt and plumage in the lickl w ere limited and, in retrospect, unsatisfactory for two reasons. [irsi, molt and plumage studies initially were a low priority in our field work. Second, our precon- ceptions concerning molts and plumages of south- ern-hemisphere waterfowl, and steamer-ducks in particular, prevented us from posing appropriate hypotheses and designing efficient methodologies for collection of data. These deficiencies have limited our knowleiige of the molts and plumages most seriously lor 7 plcncrcs and 7. Iciuocephalus. Fortunatels, by 1 982 we had worked out many of these problems so that when we had an t)ppe)rtu- nity to visit the Falkland Islands we were able to collect a limited series of specimens of T. hraclivplcni.s in a way that enabled us to provide preliminary documentation of the sequence oiniolts and plumages in that species. The preconceptions that impedeil our studies of molts and plumages in sieamer-ducks during 1979- 1981 were the following: ( 1 ) "Males of no South .-Xmerican duck ha\ e an eclipse plumage, which is so characteristic among northern-hemisphere species" (Murphy 1936:941 ). (2) Variation in pattern or aspect of the pluiTi- ages of the head and neck of male steamer-ducks is a funclum of age (Weller 1976) rather than the result of different plumages in a given cycle. (}) Waterfowl i>f the southern hemisphere in general have "simple" rather than "complex" pat- terns of plumage succession as implied by Weller ( 1968:209): "...fairl\ t\pical northern hemisjihere patterns (of plumage sequence) are apparent in southern Cinnamon Teal |.\/;(/.v< vi/z/o/vc/i/siibspp.] and .Argentine Rudtlies [Oxyiira viiialci]. suggest- ing that these are recent arri\ als to South .America," For example, Humphrev and Thompson col- lected se\ eral adull male 11\ ing Sleamer-Diicks m No\ ember 1979 which had scattered white feath- ers in the crov\n vvhich ihe\ atlribuietl to a leucisiicism when, m fact, thes were the lirst few white feathers of an umecogm/ed supplemental plumage. It was not until held work in late 19S0 and earh l''8 1 thai we considered the possibility that Fl\ mg Steamer-Ducks might lia\ c three molts and plumages per cycle. .A breakthrough in our uiuleistaiulmg of the molls and plumages of Atlantic-coastal and iiiegian STEAMER-DUCKS (ANATIDAE: TACHYERES) 47 Flying Steanier-Diicks lollowcd our organi/alion of photographs, head pehs. and skins by sex. age group, and season. We were then able lo determine that delinitive males go through a elear sequence of three molls and |ilumages per c\cle. the three plumages being worn at distinct!) different sea- sons of the \ear and ha\ ing ver\ difterent aspects. There is nothing subtle about il: the plumages of the head and neck of adult male F-I\mg .Steamer- Ducks from .-Xtlantic coastal Patagonia and L'shuaia are distmcils different and easily recognizable. The while-headed supplemenial plumage was readily explained as being attained by a presupplemental molt during the austral spring. As we noted previously (Humphrey and Live/ey 1 982a:6 1, "specimens of atlult male Fl_\ ing Steamer- Ducks in suppiemental plumage are practically non-existent in museum ciil lections, which ac- counts for the statement by Murphy (IM36:^68l that "the oldest males. ..ha\e clear gra\ heads, except for the white postocular stripe and the reddish throat patch." "" In 1^X2 and 14,X.i we collected a limited series of T. putcuhouicus in the Andean lakes of Argen- tina and the southern lakes and coast of Chile and discovered that the sequence of molts and plum- ages of adult males from those populations was not readil) interpretable in terms of what we had learned from Fuego-Patagonian coastal popula- tions. Fly ing Steamer-Ducks from the ,-\ndean lakes of .Argentina and from southern Chile (Region .\) may have either two or three molts and plumages of the head and neck per cycle (see discussion of plumages and molts for T. paiinhonivus beyond). During Held work in the Falkland Islands, we collected 20 Falkland Flightless Steamer-Ducks and were able to obtain specimens of dehniti\e males representing three distinct plumages of the head and neck along with hundreds of photo- graphs of birds in various plumages. During held work at Puerto Melo (coastal Chubut). we ob- tained specimens and photographs of 7 Ic'iicdccplhihis that indicate that the species has only two molts and plumages per cycle. Material available to us representing the Magellanic Flight- less Steamer-Duck ( T. ptcucivs ) also suggests that the species has onl\ two molts and plumages per cvcle. In summar\. our current undersiaiKlmg of the molts and plumages of steamer-ducks is as fol- low s: ( I ) The Falkland Flightless Steamer-Duck and coastal Fuego-Palagoman F-l\ing Steamer-Ducks have three molts and plumages per cycle. We h\pothesi/e that Fl\ing Steamer-Ducks from the .Andean lakes of .Argentina and Region .\ of Chile also have three molts and plumages per cycle but it is also possible that the\ ha\ e but two. (2)The White-headed Flightless Steamer-Duck and the Magellanic Flightless Steamer-Duck each have two nutlts and plumages per cycle. (?<) The basic plumage of the head and neck in both 7". hi\u hxpicnis and T palaclioiucus is sexu- alh monochromatic and similar to the juvenal plumage. The definitive basic plumage of the head and neck of T. leiicoccplialus is sexually dichro- matic and that of the definitive female is like the juvenal |ilumage. The plumages of T. piciwixs are least well known, but basic plumages of both sexes are similar to the Juvenal, and alternate plumages are lighter and onl\ weakl_\' sexualK dichromatic. (4) Dehniti\e plumages are attained during molt II in Fuego-Patagonian coastal T. /'(//(/(7)('/)/< i(,vandprobabl\ also in /'. hiiu hxpients. The detinitise alternate plumage of the head and neck in male 7". Iciuoccphalus may not be attained prior to prealternate molt IV or later. Unfortunately, molts and plumages ha\e been stLidied for very few species in the tribe Tadornini (Live/ey l'-)86a). Taclncrcs is exceptional for the comparatively detailed information on molts and plumages that is available; virtualK nothing is known about the molts and plumages of llximiuilainnis and Mciy,dnctta. genera of po.ssi- bly close relationship to Tachxcrcx (Livezey |4S6a). Some species of Tadornini are known to base two molts and plumages per cycle but we do not know whether this is consistentK the case for all species within the tribe. We can oiil\ speculate, therefore, that the h\pothetical ancestor of ItH hxcrc\ had two molts aiul plumages per cycle; the plesiomoi phic stale may be a single molt per annual cycle. We feel it most unlikely that the ancestral condition comprised three molts and plumages per c>cle because of the extreme rarit) of this pattern in the .Xnalidae. .Assuming that the 48 UNIV. KANSAS MUS. NAT HIST. VlONOCiRAI'II NO. ,S anccslial sl'(.|lh.mkc oI inojis and pluinaiies liii- per and lower e\i.-lid and distribution ot while in TacUxcrcs is two molls ami plumages per cycle, tronl of. aho\e. and behind the eye. then the sequence ot three molts and plumages per 1 he juvenal plumages of the four species of cvcle evolved independently twice in the genus, steamer-duck are no! sexually dichromatic and are once in part or all of 7'. ixiUhliiiiiii lis and once in virtually identical among the four described spe- r. hracliyplciiis. assuming that the phylogenetic cies. Head and neck of all four species in juvenal hypothesis of Live/ey ( I'^ASdc) and Corbin ci ul. plumage are unicolor dark brown or dusky gray (I9SS) for the species of Tcichycrcs is correct. v^ith the crov^n slightly darker anti an indistinct Alternatively, the three-plumaged condition may chestnut patch on the throat. Juveniles of T. have evolved in ancestral Tcichycrcs. was retained paniclKiniciis and 7'. Iiracliyplcriis have very faint, in T. pahicluiiiK lis and 7. hnicliyplcnis. and the narrow, mdistinct whitish postocular streaks. Be- suppleniental plumage secondarily lost indepen- cause of their great similarity, we Judge that juve- dently in both 7' Iciicoccplniliis and 7' picncrcs. niles of the four species would be impossible to We have been unable to identify life-historical, distinguish in the tiekl. behavioral, or environmental characteristics held Our data on predetinitive plumages in all four \nc(immonby'I\ paiiicliDnlciisundrhriicliyplcriLs species of steamer-duck are meager and difticult that distinguish both of those species from 7". to interpret. Baseil on the si/e of the bursa of Iciicoccpluiliis and 7'. ptciicrc.s and account for the Fabricius. we judge that the majority of detinitive (possibly independent) evolution of the se(.|uence plumages in all species of steamer-duck are at- of three molts and plumages per cycle in the lained b\ moll II. A possible exception is the former. Nevertheless, in 7. piiun Imiiicus and I', detinitive alternale plumage of male T. /wv/r/n/ncyz/.v. the sec|ueiice. timing, and aspects of Iciicoccplialii.s which ma\ be attained by plumages are virtually identical and the two spe- prealternate moll IV. cies cannot be reliably distinguished in the lield where they co-occur in the Falkland Islands. T ifiivmr^ n\T\riii)\i(ii'i We have examined specimens of dt)wny young of the four recognized species of steamer-duck Humphrey and Live/ey (m82a) published an (Humphrey and Live/ey 1985). The specimen of account of the molls and plumages of Flying the Flying Steamer-Duck (age class 1) examineil Steamer-Ducks based principally on fresh, sexed was from Chilean Tierra del Fuego and collecletl specimens with information concerning condition by G. Watson (LISNM 485600). Additional speci- or absence of the bursa of Fabricius. In that study mens of class-1 downy Flying Steamer-Duck col- we concluded that Flying Steamer-Ducks have lecled by M. W. Weller in the Falkland Islands three molts and plumages percNcIc and that delini- were examined subsequeni to our 1985 jniblica- ii\e plumages may be attained starting with the lion. From the meager specimens ami data a\ail second prebasic molt when birds arc about one able, we cannol determine whether there is any year of age. significant geographic variation in patterns or as- Subsequent to the completion of our 1 982 study peel of class-1 downy Flying Sleamer-Duck. We we learned that Flying Steamer-Ducks exhibit ha\e not examined class-1 downy specimens of 7 considerable geographic \ariation. Our early de- /)(//(/( /((j/»(//.v from populations breeding on moun scriptions of plumages of Flying Steamer-Ducks tain lakes of Argentina or Chile. ma\ iiol appK in detail to freshwater populations The plumage of very \oung (age class I ) downy m Chile (Region .\). the .Andean lakes of .Argen- stcamer-ducks is the oiil_\ iilumage which is abso- una. .iiul the Falkland Islands. I inforlunately. lutely diagnostic for each of the four species ol samples of fulh ilocumented specimens of Flying steamer-duck. The diagnosiic differences among Sieamer-Ducks (including data on sex. gonad the four species in the class-I downy plumage measurements, coiuiition of bursa of Fabricius) consist principally of variations in the paltern of from these |iopulalions are inadequate to inierprel the lieail. comiirising specilicall\ color ol the up- then sequences ol molls and plumages. Our I 1982) Di;H\ITIVE Pi l^MACiKS OF Malhs Basic Plimiace STEAMER-DLICKS(ANAT1DAE: TM'lDl-KES) 49 dcsLTi|itioii.s (it tliL' nuilis aiul pluniauL's ot Flyniy worn lor appi()\inialcl\ nine nionllis. I'hc tlctini- SleaniLM-Ducks lluis appl\ in dclail oiil\ to iiianin.- li\ c Mipiileniental pkiiiiagc ol the head and neck is coastal populations liom soulhein I'atajjonia and strongly scMuilly dimorphic and is worn lekilively Tierra del Fiiego. brietly. The sequence ol molls and plumages of adult The lollowmg descri|itioiis apply to marine male Atlantic coastal and Fuegian Hying Steamer- coastal populations Irom Patagonia and Tierra del Ducks comprises (Fig. '-)): (1) a prebasic moll Fuego and include, when possible, notes on plum- which lesulis in a bnelh-worn |ii\ enal-like ilark ages ot'other populations, all ol which we assume head and neck and which also replaces remiges. but cannot demonstrate to have three molts and rectrices. and the entire leather ctuit of the bods ; iilumages per cycle. Flying Steamer-Ducks prob- (2) a prealternate molt during the growth of new ably attain tlelinitive plumages with the second remiges which results in a head with dark cap. prebasic molt when they arc about one year old. brown cheeks, and white postocular streak, worn about nine months uniil mid or late spring; and {?>) a presupplemental molt which results in a pre- dominantly white head and neck wurn for one or two months from mul to late spring until the early austral summer. Thus, except for leathers of the Hccniiiiul neck. — Vary from brown, dark brown, head and neck which are replaceil three times a to dark purplish gray with crown slightly darker cycle, the body feathers of adult Flying Steamer- and posterior cheeks and side of neck slightly Ducks appear to be replaced but once per cycle by lighter in some specimens; variation (termed means of a prebasic molt which usually occurs "phases" by Humphrey and Livezey m82(/)isnot during a relatively brief time in the austral summer. age-related. Throat dark cinnamon bordered later- The same seciuenee of molts and plumages is ally by medium to dark gray. Some specimens also true for adult females in which: ( 1 ) the basic have a very short trace of a whitish postocular plumage of the heail and neck is dark and almost streak. unicolor; (2) the alternate plumage comprises a Linvcrhrcu.st.hcIlx.iiiklcrrui/cDVcrts. — White, dark gray cap. white postocular streak, and dark Upper hack. — Fresh feathers medium gray with brown cheeks; and (.^) the supplemental plumage narrow dark gray margins anteriorly becoming of the head and neck has a dark brown cap. dark browner (dusky brown) more posteriorly as the reddish-brown cheeks and has no postocular streak feathers become more extensively light silvery or only a very slight one. gr^y- Adult females from coastal Patagonia aiulTierra Scapulars. — Light silvery gray broadly mar- del Fuego appear to undergo the presupplemental gined with sepia. molt somewhat earlier than males. In addition. Lower Innk. ruiup. i/iiJ upper tail (dvert.s. — from the small sample available to us. the Medium to dark gray; leathers with taintly darker presupplemental molt in adult males from Tierra margins. del Fuego may occui as much as a month later than Upper hraisi and .sides. — Fresh upper breast in Puerto Deseado. leathers cinnamon becoming slightly more red- In. Atlantic-coastal aiul Fuegian Fly ing Steamer- dish distalK and broadh tipped with blackish Ducks of both sexes the tielimtive basic plumage brown with a subteiniiiKil patch of light sihery of the head and neck is acquired immediately prior gray. Laterally, the leathers are less cinnamon and to and tiiiring the onset of the prebasic molt of the medium grav until on the upper sides there is no w ing and closely resembles the luvenal plumage. cinnamon. .Also the more anterior upper breast This is replaced during prebasic molt of the wings leathers are darker cinnamon. There is consider- by the alternate plumage of the head and neck able indivitlual \ariation in the extent and shade of which exhibits moderate sexual dichromatism. cinnamon on leathers of ihe upper breast and differs in aspect from Ihe juxenal plumage, and is upper sides and in the disti ibuiion of leathers w ith 50 UNIV. KANSAS MUS. NAT. HIST. MONOdKAI'll NO. X ciniianmn b;iscs. .Some iiuli\ ulii;ils lia\c \l'I"\ lilllc cinnamon on the bases ot the upper breast leathers. This variation is not clue to wear and lading: ue have no evidence that tliere is more than one moh of upper breast anil sides per cycle. .S'/ and the clieeks anti lores light gra\ with posieric>r cheeks and base of the neck white. The hnver cheek was slightly darker and the throat was niediiuii reddish chestiuit. In the bright sun this bud woiikl look white-headed in the held. It IS possible that the supplenienlal plumage of the head ami neck ol atlult males from the Andean lakes of Argentina and the southern lakes of Chile becomes increasingly white in older birds. How- ever, there is stronger evidence to suggest that, if these populations have three molls and pkimages percycle. the detmitive supplemental plumage has gra\ cap. fuscous cheeks and a prommenl white postocular streak, and resembles the alternate plum- age of coastal birds from southern Patagonia and Tierra del Fuego. DKFtMTivE Plumages of Femai.e.s streak occluded postei"ioil\ b\ incthiim bro\Mi becoming a whitish patch on sitles of neck: throat dark cinnamon, neck medium brown with paler, almost whitish collar. Supplemental Plumage //(■(/(/ (iihl link. — Crown medium gray with brownish cast to dark grayish-brown; lores and cheeks fuscous chestnut to dark reddish brown, grading to dark grayish brown and then darkish metlium gray on the neck; throat medium chestnut. Ihe white postocular streak is short. While similar to the alternate, the supplemental plumage differs in lacking the white collar, and in having a very short postocular streak and ;i pronounced reddish cast 111 the lores. Predei-imtim-. Piamage.s (Both St \es) Basic Plumage Ih'ihl iiihl iiciL. — Dark chocolate brown; cap darker in some individuals; neck medium brown in some individuals; throat dark cinnamon; eye lids white; white postocular streak short or (possi- bly) absent. Lower hic'iiM. helix . iiihlci mil cavcrts — White. Upper hack. — As in definitive w liite male ex- cept that feather margins are sepia to brownish- olive and wider. Lower hack, ritnip. and upper tail covens. — Dark gray; feathers of the low er back and rump are faintly silvery and have narrow, indistinctly darker edges. Upper hreasi and sides. — As in definitive male. Sides and jlanks. — Slightly darker than those ot detmitive males, although the ililference is not a reliable character lor determining sex. Sides ap- pear to be replaced only once per cycle. The hrst basic siiles and thinks are identical with those ol sLibsc(.|uent basic plumages except the chestnut margins appear to be slightly narrower. Alternate Plumage Head and neik. — Forehead and crown dark gray; lores and cheeks dark brow n; white postocular Juvenal Plumage The following account ilescribcs a specimen (KU 7M2I1), one of two males collectcti on 20 .lanuarv l^'SI at Puerto Deseado from a family group of five juveniles accompanied by a pair of ailults; the two males collected were identical in aspect. Although we have examined no lemales in juvenal plumage we presume thev are identical in aspect to males of similar age. Head and neck. — Dark brown, crown slightly darker, patch on throat chestiuit. Upper and lower eyelids white; narrow, ill-dehned pale buffy postocular streak extending the length of the cheek. Lower hreast. helix . umlcr unl coverls. — White. Upper haik. — Feathers silvery gray with dark, almost blackish gray margins, giving a scalloped effect. Scapulars. — Silvery gray with tiarker blackish margins. Lower hack. rump, and upper tail coverts. — Medium gray. Upper hreasi and sides. — f-eathers pale silvery grav with dark almost blackish gray margins. No chestnut at the bases of any of the feathers of the upper breast and sides except for the last rows of feathers just before white leatliers of the upper breast. 52 UNIV. KANSAS MUS. NAT. HIST. MONOGRAPH NO. S ^444 Scd sS sy < u. a. u- H U-cyj Z tup UJ_1 iu< ul Qc/n Q < Qoa > 1-1 ? O O STEAMER-DUCKS (ANATIDAE: TACHYERES) 53 < 5S:i Zg ZJ u-v: u. [- Eg" Qco Q< S;^ o o o -'•'3 54 UNIV. KANSAS MUS. NAT. LSI. MONOCIRAPII NO. S .S'/(/<'.s iiiul lliiiiks. — Fe;ithers silvery gr;iy v\ itli blackisli eia> margins; the tlank feathers are nie- diiiin gray v\ ith very narri)\v. washed out brownish or chesliuii margins. Downy Plumage The following description is based on three specimens from Chile: USNM 4S56()() (class-l, female, 1 February 1964), FMNH 120521 (class- II. female, 28 January 1940), FMNH 1 20?22(class- II, 28 January 1940). Head and neck. — Upper eyelid dark biownish oli\e; lower eyelid whitish. Cheeks, lores, lore- head, crown and nape dark brownish olive. Supraocular and supraloral patches are whitish and very narrow, becoming even narrower anteri- orly: they are widely separated from the postocular streak which is broad and whitish. Upperparts. — Yoke light fuscous; lower back and rump dark brownish-olive. Undcrparts. — Upperbreast brow nish-oli\e; lower breast and belly white. Taciiyfrks hrxchyptervs Series of specimens of the Falkland Flightless Steamer-Duck collected in Februar\ 19S4 tlemon- strate conclusivels that this species, like the Fly- ing Steamer-Duck, has three molts and plumages per cycle (Fig. 9). Detiniti\e plumages of both sexes are indistinguishable from those of Atlantic Coastal and Falkland populations of the Fl\ing Steamer-Duck anil seasonal occurrence of the three dclniiti\e plumages appears to be appro\imatel\ the same in the two species. Our understanding of aspects and timing of predelinilive plumages is \ers liiuned. but we suspect that (.lelinitive pliuii aees are attameil duruii: molt II. neck; narrow, rather short white postocular streak. Chin medium dusky brown: throat chestnut. Fore- head dark chestnut mi.xed with light gray feathers; crown chestnut, darker on the nape. The prebasic molt of the head and neck has just begun in an adult male (KU 80.52.5) collected on 14 Februar\ 1984; the specimen had no bursa of labricuis. In this specimen ilark blackish brown feathers are replacing the supplemental w hiie feath- ers of the forehead, lores, and anterior cheeks. Two adult males (KU 80515 and KU 80520) collected on 9 and 10 February (neither with bursa of Fab- licius) are in lull basic plumage of the head and neck except for the crown, which is molting into the light to medium gray ot the alternate plumage. Lower hrcasr. helix, under tail coverts. — White. Upper hack. — Feathers medium gra\. the more posterior ones with broad blackish brown margins and a silvery gray wash. Scapulars. — Sihery gra_\ with broad, dark chestnut margins. Lower hack. rump, and upper tail coverts. — Medium gra\ becoming somew hat lighter posteri- orly. Upper hreasi and sides. — Upper breast dark brovM) with faint margins of pale gravish. The indi\ idual leathers are metlium chestnut w ith broad dark brown terminal banil and. in the more poste- rior leathers, a narrow subtermiiKil baiiil ol pale gray. With wear the upperbreast becomes increas- ingly chestnut in appearance. The leathers of the sides are silvery gray with wide blackish brown margins. .V/(/c,s ami on the hiiul cheeks dullish brow n becoming somew hal lighter STEAMER-DUCKS (ANATIDAE: TACHYERES) 55 aiul izruNCi" iiosienorlN. Hiiui neck and sides of neck pale to light gray, darker and more brownish in some individuals. Chin medium gray, throat and \eniral neek chestnut. Long, white posiocular streak, more prominent in some individuals than others. One specimen (KU 80517) is in hea\ y prealternate molt of the head and neck and ni \ ery heavy prebasic molt of the body; the old worn remiges were still firmly attached. Prealternate molt of the head and neck may occur as late as February and as early as October or November. Color slides provided us by O. S. Pettingill. Jr.. M. W. Weller. and T. Narosky show bright-billed, presumably definitive birds in alternate plumage in November. December, and January. We photo- graphed and collected definitive males in alternate plumage in Januar\ and February. Supplemental Plumage //(■(/(/ (///(/ iici k. — The definiti\ e supplemental plumage of males has the throat mednim to dark chestnut and the rest of the head white. It appears that some individuals have completely white crowns and napes. vUiile others have crown and nape pale to medium gray. We have seen no speci- mens in presupplemental molt or in fresh detini- tive supplemental plumage of the head and neck. All specimens we have examined are in worn supplemental plumage with the head and neck predomniantls white except for dark incoming basic feathers in the lores, forehead, anterior crow n and anterior cheeks. We ha\e examined specimens and plK)togra|ihs of definiti\e males with \arying amounts ot white supplemental plumage on the head and neck indicating that the presupplemental molt may start as early as October and as late as December or January. DiiiMiiM PiA viaCjES of Females Basic Plumage Comparison of specimens show s that, except for plumages of the head and neck, the basic plumages of detinitne males and females are identical. Hcciil and ncik. — The heads and necks of four females without bursa of Fabricius collected in I-ebruary all appear to be mostls in tlelimtne basic plumage with varying amounts ot new alternate plumage. All four specimens (KU 80516. KU 805.^2. KU 805 1 3. KU 805 1 8 ) have fresh, unw orn. new remiges. In these four specimens the lores and anterior cheeks are dusky to blackish brown be- ciiming chestnut more posteriorly. The forehead, crown, nape and hind neck are dusky brown be- coming lighter and somewhat grayer posteriorly. The throat and ventral neck are dark chestnut. The eyelids are white and some individuals have a very short white postocular streak. .Alternate Plumage lUiiil uiul neck. — We ha\e not examined any specimens in full alternate plumage of the head and neck. Photographs indicate that the definitive alternate plumage of the head and neck of temales is similar in aspect to that of the Atlantic-coastal populations of Flying Steamer-Duck. The crown IS medium to dark gray; lores and cheeks medium dull grayish-brown; long white postocular streak; throat chestnut. Supplemental Plumage Hciid and neck. — LInknown. Predefinitive Pllimac.es (Both Sexes) Juvenal Plumage Slides taken by T. Narosky in December 1978 (file no. 2692) and February 1078 (file no. 2685) at Port Stanley show two indi\ itiuals in lull juvenal plumage. The remiges on both individuals in each photograph are partially grown in that the white secondaries are barely visible be> oiul theirco\ erts and the tips of the primaries are not e\ idem. We assume that, as in other species of steamer-duck, there is no sexual dichromatism of the juvenal plumage in this species. Head and neck. — Unicolor dark brow n; upper and lower e\elids white; narrow, pale bufl\ postocular streak extends lor about a centimeter posterior to the eye and then becomes broader 36 UNIV. KANSAS MLIS. NAI . HISI. MONOGRAPH NO. 8 and \ciy taiiil. luixIiil; vcnlrall) posiciioi to ihe species ol stcanicr-duck. the pivallcriiatc iiioll ap- chcek. parenlly iinoKes onh feathers of the heaii and Lower breast, belly. Kiiclcr tail coverts. — White, nock (Fig. 9). We have found no evidence that Upper back. — Feathers medium gray with dusky leathers of other pterylae are replaced more than brown margins. once per cycle. .Scapulars. — Medium gray, broadly margined Tlie definitive basic plumage of the head and neck with dusky brown. of male T. pieneres does not resemble the juvenal Loner hack. rump, ami upper tail coverts. — plumage. Thus there is sexual dichromatism of the Medium gray, each leather with narrow diisk\ detinitive basic plumages of the Magellanic Flight- brown margin. less Steamer-Duck: the females have dehnitive ba- Upper breast and siJes. — While the ventral sic plumage of the head and neck unicolor mediinii upper breast is not visible in the photographs, the gray whereas the definitive basic plumage of the feathers of the sides of the upper breast are me- head and neck of males has a meelium gray cap and diuni gra\, broadK margined with dusky brown. lores, light gray cheeks and neck, and pale gray to Sules ami Jlaiiks. — Feathers medium gra> w ith w hitish. rather short postocular streak. The Magel- broadduskv brown margins. In one indivitlual. the lanic Flightless Steamer-Duck is unique in the genus elongate Hank feathers are light to medium ilusks m that the detinilne basic plumages of the head and brown w ith darker margins. neck of neither se,\ resemble the |u\ enal plumage. We have examined specimens of male Magel- Dowii\ Plunri"e lanic Flightless Steamer-Ducks in detinitive alter- nate plumage collected in November. December. The following description is based on live and January, many of them in the early stages of unsexed. class-I specimens from the Falkland Is- prebasic molt of the head and neck. In addition, we lands: AMNH 419160 (7 December ]^\5). MCZ haveexammed four specimens from thcXmerican 70.^21 (15 December 191.5), MCZ 70522 (figured Museum of Natural History, collected by Beck inMurphy 1936), BM 19.^0. 12. IS. 1. BM (nonum- near C'hiloe Island, also in tlelinitise alternate ber, 29 November 19,^61. plumage of the head and neck. We have seen two Headamlncck. — Llppereyelid medium tuscous: specimens (taken m December and .lanuary ) in lowereyclid whitish lopale fuscous. Cheeks, lores, definitive basic plumage of the head and neck, forehead, crown, and nape medium fuscous. The Nine additional specimens (taken during .April- very pale(almost whitish)smoke gray supraocular July) are in definitive basic plumage of the head ami sLipialoral patches are uninterrupted, very nar- and neck anil one ot them (.AMNII 44.^670) still m row and even narrower at the junctions of the prebasic molt ot the head and neck, supraloral and supraocular patches and the From the limited data at ouidis|iosal. we specu- supraoculai patch aiul postocular streak. The \ en- late that (he majoritv of adult male Magellanic tral margin of the su])raocular patch abo\e the Flightless Steamer-Duck are in alternate plumage uppereyelid is dark dusky brown. The supraocular o| ihe heatl ami neck during the late spring and patch is coniiiuious wiih llic posi gray along the rachis. Lower hack, niiiip. and upper lail cti\'erl.\. — Feathers medium to (.lark gray with slightly darker margins. Upper hreasi and \ides. — Feathers of the upper breast are banded with a \ cry narrow pale slightly worn smoky gray tip; a subterminal band that is blackish-brown and is broader anteriorly and nar- rower posteriorly; the next band is variable in shape and size and color, being cinnamon in more anterior feathers and becoming faded cinnamon posteriorly and hnally becoming medium gray in the more posterior and lateral feathers including those of the upper sides. Sides and flanks. — Feathers light silvery-gray with medium blackish-brown margins. .Sides and Hanks are moderately worn in a specimen t;iken in November and the dark margins, especially ante- riorly, are narrower and the feather tips fra\ed and light smoke gray. l\c})U'^e\ and rectrices. — Black or blackish- brown with varying amounts of silverv-grav on their dorsal surfaces. Alternate Plumage llciul iiuil neck. — An adult inale (AMNH 44.Vi(iM) collected on 19 May at Chiloe Island has crown and lores light gray becoming slightly darker anteriorly; cheeks pale gray becoming whitish posteriorly. White postocular streak present, and chin pale gray. Throat with very small patch of pale chestnut becoming paler and grayish/whitish at its margins. Neck pale gray dorsally grading to w hitish ventrally. Other adult male specimens in alternate plumage of the head and neck from Chiloe Island are AMNH 443661 (12 May) and AMNH 443671 ( IM May). In addition, an adult male (AMNH 733418) collected on 27 Novemberat Frutillar(near Puerto Monti) Chile was in quite wurn pluiTTage with old, frayed wings. The head and neck appear to be in worn alternate plumage. The forehead is light faintly huffy gray becoming darker on the crown which is medium gray. The lores are medium gray. Cheeks light smoky gray becoming whitish posteriorly. Chin pale smoky gray. Throat with diffuse light- medium chestnut patch. Neck worn and whitish. The definitive alternate plumage of males is. except for light gray crown, brownish-gray lores and pale gray neck, all white with an indistinct patch of pale cinnamon on the throat. A November specimen from Tierra del Fuego (KU 77969) and a December Chilean bird (KU 79S42) are in this gray-capped alternate plumage in which the rest of the head and neck is white. Di iiMiivi; Pi.iiMACiKS or F[;mali-:s Basic Plumage Comparison of series of s|iecimens of definitive males and lemales at the American Museum of Natural llistoi\ rc\cals iluit. other than the head 58 UNIV. KANSAS MUS. NAT. HIST. MONOGRAPH NO. 8 anil neck, iho tlcliriili\e basic plumaucs ol'llic luo sc.xcs arc itlcnlical. //(■(/(/ anil neck. — Forehead, crown, and lores mciiuMii darkish gray, feathers of forehead with tainl. paler margins ( from wear and fading). Cheeks medium gray or medium smoke gray becoming darker anteriorly. Chin and neck medium gray. Iiulisimci ihunib-si/cd patch of medium chestnut on Ihroal. l-aml, ill-detined. short poslocular streak light gray, mottled liarker. Examination ot specimens taken during De- cember (KLl 798.V^) and November (KU 77967) indicateil that the detinitive basic head and neck is unicolorgray with no white or whitish postocular streak. The first specmien had dropped its remiges and was in heavy prehasic molt of the head which was about three-c|uarters complete. The second s]iecimen was in high basic plumage of the head and neck and is starting the prealternate moll; of particular note m the specimen are the obviously grow ing. white postocular feathers. Alternate l^lumage Head (111(1 lu'ik. — Crown and forehead dark gra_\. becoming paler on the nape: lores dark gra\ becoming meilium gray on cheeks and fading to light gray and then pale gray — almost whitish — at base of neck. Short |iale gra\ to whitish postocLilar streak. Chin medium gra\ ; throat varies trom small- ish patch of pale cinnamon or reddish brow n to a more extensive patch of ilull chestnut. Wear aiul lading may account tor some of this \ ariation. ( )ne December bird (Kf 79S,V)) was beginning prealternate moll of the head and neck and aheatly had a pale gray postocular streak. Pri:iii-;ii\iii\i Pi i \i \(.i;.s (Bnm .Si \i si .Alternate I'lumage //(■(/(/ (iiul iifi k— \\\o males ciillected m No- vember hail crow n. lorehcail. nape, lores, aiul chin medium gray. Cheeks light gray. Throat faintl> marked pale cinnamon. The extent and strength ol the cinnamon on the throat \ aries from practicalls indiscernible lo a ilisimcl pale patch. Jmenal I^lumage Examination of nine specimens of Magellanic F-'lightless Steamer-Duck in full jiivenal plumage, collected at \arious localities in March. April. May, and July, revealed that males and females are identical in this plumage. Observations by N. and J. Goodall (pers. comm.) indicate that the pre- juvenal molt in I . ptcncrcs may not begin uiiiil the young birds exceed 60 days of age. It is not known iiow long the juvenai plumage is worn nor the age at which the first prehasic molt begins. From the ten specimens (one unsexed) at hand we suspect that the onset of the Hrst prehasic molt in Magel- lanic l-lighlless Steamer-Ducks is much delayed compared to most other tadornine and anatine waterfowl. Head aihl neck. — Forehead, crown, nape, lores dark (purplish) gray: neck medium dusky gray, lighter ventrall\. Cheeks medium lo darkish dusky gray becoming dark anteriorly and in the lores. Chin medium dusky gray. Thumb-si/ed patch of medium brovsnish chestnut on throat. Lower hieasl .helly.undeiiail Cdveris. — White. Upper hack. — Medium dusky gra\ish-brown. Posteriorlv the leathers ha\e tlark duskx -briiw n margins gi\'ing a faintl\ scalloped appearance. Scapniars. — Medium gray ish-brow n w ilh dark ilusks-brow n margins. Loner liack. rump, and upper tail covets. — Medium to dark grayish or dusky brown. Upper hreasi and sides. — Feathers mcilium dusk\' gra\. more or less hea\ il\ tippetl tiark hlack- ish-brow n becoming less hea\ il\ marked on up]ier siilesand paleraiul lessdisiinct posteriori). Feather bases are pale smoky gray. Sides and flanks. — Medium dusk\ brow ii. leaih- ers liarker low aid tips ami becoming slightls brow n- ish posteriori). Some leathers ot sides wiih faint traces of pearl\ gra\ along distal rachis. R(-nii'..;es and rectrices. — Blackish brown with slight wash of siKery gra\ on dorsal surlace near rachis. i'rimaries ami greater upjier priniarv co- \erlsdaik dusk\ brown with blackish brown shafts. Secondaries white. .Axillaries and central part of wing lining white; b;ilance of umler wing coserts mediuiii dusk\ hiciwii. the giwiler umler primary co\cils p;ilci. ketnces medium bfickish-brow n STEAMER-DUCKS (ANATIDAH: lACIDERES) 59 with bkick sliall ;ind vei'_\ laml mesial wash ol silvery gray. Dow n\ Pliiiiiaye The IoIIowihl; (.lescri|ilmii is based on eight class-I specimens troni Chile: AMNH 443684 (male. 3 December IMI4i. AMNH 443683 (male. 4 December 1914). AMNH 443687 (female. IM Jaiuiary 141?). AMNH 443689 (male. 30 Novem- ber 1914). AMNH 443704. 44370.3. 443706. 443708 (3 males. 1 female. 11 January 191.3). Ilcuilancl neck. — LI pper eyelid blackish-brown; lower eyelid whitish. Cheeks, lores, forehead, crown, and nape dark brownish-olive becoming lighter on the anterior forehead. Supraloral patch very small or absent; supraocular region blackish brown except for a whitish patch which may be absent, faint, or small but when present is always separated from the postocular patch and from the supraloral patch when it is present. Postocular streak whitish and di\ ided into separate anterior and posterior parts. Vppciparts. — Yoke medium brownish-olive; rest of upper parts dark brownish-olive. Viulcrpaits. — LIpper breast brownish-olive; lower breast and belly white. Tachyeres levcocephalvs In theirdescription o\ Tlk hxcre.s leindccphalus. Humphrey and Thompson (1981:8) stated that "from examination of specimens and photographs of T. leiicocepluiliis. we judge that adult birds of both sexes go through a complete prebasic moll in summer (February), shedding the remiges simul- taneously and then without interruption undergo a partial molt involving the head and neck and pos- sibly other parts of the body. Adult males collected in September were white-headed as were those with worn wings collected in February before they had initiated the prebasic molt. The limited data at our disposal suggest that either adult males wear a white alternate plumage of the head and neck most of the year or that, if there is a supplemental plumage, it too is white. ..we tentatively assume a two plumage cycle since we have no evidence to the contrarv."" ■Since that was w ritten. v\e have examined many additional specimens of the White-headed Flight- less Steamer Uuck and have fouiul no evidence for three molls and plumages per cycle in 7'. /(7«v)((7'/;(//((.v; nevertheless, a supplemental plum- age may remain undetected. Although the hypoth- esized pattern of two molts and plumages per cycle for this species best explains the limited data at our disposal, study of specimens representing all sex and age classes throughout the year will be needed before a full understanding of the plum- ages and molts in this species will be possible. Some of the puzzling data that need explanation include: (1) May and September-October speci- mens undergoing body molt in certain tracts other than head and neck; (2) female specimens un- dergoing moll in sides, flanks and other body tracts (Other than head and neck) in September-October but not males; and (3) definitive alternate plumage of the head and neck of males apparently not attained until the third or later prebasic molt in contrast to coastal Flying Steamer-Ducks wherein the delinitive alternate plumage apparently is at- tained by the second prealternate and molt. Since molts and plumages of steamer-ilucks appear to be tightly linked to their reproductive cycles, some of the apparent variability in sea- sonal occurrence of birds in molt and various plumage states may be attributable to individual sariation in breeding activities. Although it is evident that the majority of White-headed Flight- less Steamer-Ducks nest during the austral spring and summer, there may be substantial variation in extreme dates. Based on available data, we hypothesize the following sequence of molts and delinitive plum- ages for male White-headed Flightless Steamer- Ducks (Fig. 9); ( 1 ) a prebasic molt which results in gray cap. red-brown cheek, and white postocular streak on the head and neck and which also re- places remiges. rectrices. and the entire feather coat of the rest of the body; (2) a prealternate molt which results in an alternate plumage of the head ami neck vi hich is predominantly white and which is acqLiiied during the fourth and subsequent prealternate molts. .As far as wc can determine, except for feathers of the head and neck w hich are replaced two times a cycle, the body feathers of 60 UNIV. KANSAS VIUS. NAT. HIST. MONOGRAPH NO. S adult Whiic-hcadcil I'lighlless Sleamcr-Ducks arc replaced bul once a cycle by means of a prebasic molt which usuall\ occurs during a relatively hriel time in the austral summer. The same sequence of molts and plumages is also true for adult females in which the basic plumage of the head and neck is unicolor dark brown with a small, white postocular streak. The delinitive alternate plumage of females comprises a dark gray crown, reddish-brown cheeks, and a long. uninterru|ited relatively broad, white postocular streak. in contrast to T. hniclixpwius and /. Ihiuiclioniciis. in \\ hich the definitive basic plum- ages are dark and unicolor and essential I \ indistin- guishable Ironi those of females, the delinitise basic plumage of male /. Iciivoccpludus differs from that of females and has gray cap. dark cheek, and v\ hite postocular streak. Except for bill color, basic plumages of the head of male and female /. hriiilnprcnis dnd l\ pdhiiiii iniciis show little sexual dichromalism and resemble the Juvenal plumage. The only way we can account for gray-capped, darkish-cheeked males molting into another gray- capped, darkish-cheeked plumage is by hypoth- esizing that the pretletinitive alternate plumage of the head and neck is similar or identical to the basic plumage. We can tind no evidence that the sides. Hanks, and possibly other tracts (apart from the head and neck) molt more than once per cycle. Neverthe- less, we have examineil specimens of both sexes molting or in fresh sitles and flanks in May. and of females molting or with fresh sides and Hanks in September and October. We could detect no differ- ences in the latter case between fresh sides and Hanks of September-October birds and those of birds collected in I-'ebruary. Predelinitive. i.e.. first basic and first alternate plumages of the White-heatletl I-'lighlless Steamer- Duck are either imknow n or poorly uniierstood. Dii iNriivi-: Pl.t MAGrs ot M.\ri-s Basic Plumage llciid iiihl ncik. — I-orehead. crown, and nape dark siray: cheeks and lores medium reddish-brow n; broail white postocular streak; sides of throat and chin medium gray: extensive patch on throat me- ilium cinnamon: white collar at base of neck. For birils that nest in the late spring or early summer it appears that this plumage of the head and neck is attained during the prebasic molt which follows nesting and is worn until early austral spring (Sep- tember-October). We collected a male in Decem- ber, one of a pair w ith \ ery small dov\ nies: the bird was in high, w hite alternate plumage with a very lew tiark basic feathers growing in on the cheeks and anterior forehead. The wings of this bird were old and worn. We believe that Humphrey and Thompson ( l'^)SI:'^ have broader dusky-brown tips than those in the sides. Three September specimens and one col- Haul iiiul iu\k. — Unicolor dark brown, neck lected in December have worn and laded sides and slightly paler; small, while postocular streak, flanks in which tiie tips have become lighter and Lower hreasr.hclly.iiihlcrhiil coverts. — White, browner. In the December specimen wear has Upper hack. — As in delinitive males except made the dark leather tips narrower and with pale that feather margins are wider aiul are sepia to frayed edges. It appears that the sides and Hanks o\ brow nish-oli\e in color. definitive males are replaced only once a cycle Sicipiilars- — As in dettnitive male except that during the prebasic molt, usually in the austral the featiier margins are wider and sepia to brown- summer. Thus, males are wearing worn sides and ish-olive in color. flanks when the heatls and necks are in fresh Lower haek. ruiup. and upper tail coverts. — alternate plumage. Dark gray, feathers of the lower back and rump Remi^^es and rectrices. — Black or blackish- faintly silvery with narrow, indistinct darkeredges. brown with varying amounts o\' silvery-gray on In worn birds (several February specimens), the their dorsal surfaces. Primaries and greater upper leather edges are frayed and broadly tipped with primarv coverts dark dusky-brown with blackish- huffy brown and worn smoke gray tips, brown shafts; rest of upper wing medium fuscous. LI pper breast and sides. — As in definitive male. Secondaries white, the inner vane of the innermost A specimen collected in September had fresh up- ones medium blackish-brown; teilials medium dusky per breast and sides with a very few new feathers brown. AxiUaries and central part of wing lining still growing. It is puzzling that some females were white; balanceofunderwingeovertsmediumdusky- molting or were in fresh upper breast, sides, and brown, the greater under primarv coverts paler, flanks in September. Rectrices dark blackish-brown, with black shaft and Sides and thinks. — Light silvery gray (as in faint mesial wash of white silvery-gray. definitive malesi with feather margins broadly chestnut. Sides and flanks of delinitive females m fresh plumage have much richer reddish and w iiler feather margins than males; this gives the sides As lar as we can determine, only the leathering and flanks of definitive females a more heavily of the liead and neck is replaced during the scalloped appearance than m males. Sides and prealternate molt. flanks of a definitive bird collected in September Head and neck. — Predominantly white. Some were identical in appearance to new feathers m individuals have a medium gray cap of varying February specimens. We are uncerlani about num- extent (size and extent possibly varies with age); ber and timing of molts of sides and thinks in in others, the forehead and crown is white. There definitive females. We have found extensive molt are varying amounts of pale smoky-gray in the in delimlive lemales m both September anil Febru- lores and anterior cheeks. The chin is pale smoke- ary but the leathers are identical. We have found gray grading posteriorly into a relatively narrow noevidenceof moliduring Seplemberof sides and patch of light brownish-red or light cinnamon on Hanks in definitive males, the throat. The prealternate molt apparently is A leucistic female 7. /(7((V*((7)/«////.s ( SW .vS,^ I Alternate Plumasze 62 UNIV. KANSAS MUS. NAT. HIST. MONOGRAPH NO. 8 = KIJ 77936) vvascDllcck-d at PuciU) Mclo. C'luibiit on 28 September 1979; the bird was evidently an adult (ovary 20 x 20 nun. body mass 2S?() g). and was conspicuously liizhicr than nearby conspe- citics, even al a distance. The leiicisiicism affected all pterylae. Alternate i'kmiage llcoil (ind iivck. — Crown gray, cheeks redilish brown becoming light grayish-brown posteriorly. long, unmterrupted, white postocular streak. Predefinitivi; Pium.age.s or M,\i.i:s Basic Plumage Head and lu'ck. — A specmien (KU 79243) col- lected in February from a family group comprising two adults and four or Hve young had wings onl\ partly grown with the primaries about 1 0 cm out of their sheaths. This specimen has slight molt on the heatl and neck which we interpret to be (he end o\ the lirst jirebasic molt. A male (KU 79233) collected on 1 1 February had a vestigial bursa of Fabricius and had just completed most of v\ hat we considei to have been its third prebasic molt. However, this prebasic molt of the heail antl neck was still tuidervvay and ihe alternate iilinnage being replaced on the head hatl ilarkish cap. cheek and w hite postocular streak, suggesting that the preiietinitive aliernale plum- age of the head anti neck (second alternate) is similar in aspect to the detinitive basic plumage. Another male (KU 79236) with vestigial bursa collected S February had grow ing remiges. prima- ries about 10 cm long and secondaries about 1.3 cm, and was in heavy molt in all regions of Ihe body. The retained, worn, presumably secoiul al- ternate feathers of the head and neck were compa- rable in aspect to the delinitive basic plumage. We hypothesize that the dehmtive alternate plumage ol the head and neck ol niales does not occur until three years ol' age. i.e.. before the thiril or subse- t|iieni preallernate molts. Sides and Jianks. — New lirst basic feathers growing in on a September male with many re- tained juvenal leathers are like the dclmiliv e basic feathers of the sides and Hanks. Pki:di:iimii\ L PlL-\i.jiGi;s oi- Fi;mali£s Basic Plumage Upper hack. — Compared to the definitive fe- male, feathers of the first basic female upper back have less intense silvery gray and narrower mar- gins that are dark gray. Scapidais. — Compared to definitive females, the scapulars of the first basic female are less intense silvery gray and have narrower margins that are brownish-olive. The first basic plumage is less "contrasty" silver versus rich brown than is the definitive basic plumage of females. Lower hack. rump, and upper rail coverl.s. — A female collected in September had lower back and rump as in definitive female. Upper hreast and sides. — Upper breast and sides of iwo females collected in February with large bursae (in first basic plumage) were like definitive basic upper breast and sides. Sides and flanks. — A presumably subadull fe- male collected in September (ovary 2.3 X 13 mm) had unworn sides and flanks light silvery gray (more extensive on each feather than in definitive birds) and with narrower chestnut margins which were less richly chestnut than in definitive birds. A female laken in February with vestigial bursa had fresh sides anil Hanks mixed with more light sil- very gray on each feather and narrower brow ner margins than in the ilefinitive specimens. Jiivi;n.ai. .vnd Downi Pi i m.ac.es (BoiH Si:.\ts) Juvenal Plumage We collected Ihree s|iecimeiis (two males, one female) m complete juvenal plumage (KL' 7924. KU 79243. and KU 79244). All three specimens were collecled from family groups in February 1981 at Puerto Melo. Remiges on each of the specimens were only partly grown, hav ing devel- opeil 3-10 cm i)ui of their sheaths. Based on these specimens, ihere is lu) sexual tlimorphism in ihe juv enal plumage and birds of both sexes are iden- tical at this stage of deveU)pmeiite\ce|M iluil males are somewh.ii lari;er ihan tem.iles. STEAMER-DUCKS (ANATIDAE; lACHYERES) 63 /Icciil diiil ih'ck. — LInicoliir tlark bidvsn. neck paler; iiKlisiinct pale bLiHy poslociilar slreak. Lower breast, helly. iiiuleriail coveris. — White. Upper hark. — Feathers medium gray but siigiillv darker than tiiose on the upper breast and sides. Kach leather has a dark, blaekish-gray ter- minal band 3—4 mm « ide. Scapulars. — Outer webs medium gray: inner webs medium brownish-gray. Each leather has a blackish-brow n margin: some leathers hav e a taint tan tip which may be a vestige ol the lormerly attached down. Lower hack, niiiip. and upper tail coverts. — Mediimi gray. Upper hreast and sides. — Feathers dull me- dium gray or brownish-gray for most of their lengths, with a blackish-brown subterminal band about 2-3 mm wide and a terminal band of light brown. A few feathers at the junction of the upper breast with the v\hite lower breast have a trace of mediinn cinnamon just proximal to the dark termi- nal band. Sides and flanks. — Medium brownish-gray, each of the feathers with a taint v\ ash of pale pearly gray aiul a medunii-hrow n margin, becoming slightly lighter at the lip. Downy Plumage The following description is based on hvechiss- I specimens from Chubut. Argentina, collected during 12-14 December I MSI: MACN 5269S (male), KU 79624. 79625 (unsexed anatomical specimens), KU 79501 (female), and KU 79502 (male). Head and neck. — Upper and lower eyelids whitish to pale pearl gray. Cheeks light to medium grayish brown becoming paler ventrally and pos- teriorly in some individuals. There is a dark gray- ish-brown streak through the eye along the dorsal margin of the cheeks and lores. Fores light to medium grayish-brown. Supraloral patch broad and continuous with the supraocular patch and poslocular streak, all being whitish or pearl gray. L'ppeiparts. — Yoke light grayish-brown: rest of upper parts dark grayish-fuscous. UnderpiU-ts. — Upper breast medium grayish- brown; lower breast and belly white. DIAGNOSTIC CHARACTERS Generic Characters E.XTERNAl. CliAKACrRR.S Steamer-ducks of all species are readily di.stin- guishable from other waterfowl by the combina- tion of large size (2-6-f kg), white wing specula, predominantly gray body color w ith white under- parts, heavy bill, dull reddish throat patch, bright orange feet (in adults), variably developed wing- knobs, and (in most plumages) light postocular streaks, and the absence of metallic hues or contrastingly pale fore-patches on the dorsal sur- faces of the wings. The three flightless species of Taeliyeres are the only large (exceeding 1 kg in body mass) extant anseriforms that are perma- nently incapable of flight. Within their natural distributional range, steamer-ducks conceivably could be confused only with the much smaller Crested Duck (Lophonetta speciilarnndes} or am of the three sympatric species ot sheldgeese (Chloepliai;a): both of these genera are readily distinguishable from Taeliyeres by their metallic wing specula, dark bills, variably patterned but non-gray body plumage, ami (in Clilne or two second- aries." We founil it difticult to determine the anunnit of spoiling that should be considered "slight." and the extent of spotting that should be classitied as "subterminal." Further problems resulteil from the variable basal shailing noted in man\ birds, and the contmuum of shades from white through gray to black that was observed. Whaie\er rules one adopts, the shading pat- terns in secondary remiges of T. picncrcs and T. puiavhoniciis appear to be quite similar, and any difference in "modal" condition would be unreli- able for species diagnosis. We found that T. puiaclioniiiis almost never has 12 largely white secondaries: this was true of all the other species as well. Specimens of all four species typically had 10 to II "largely white" secondaries, although there was a tendency for T. picncrcs to ha\ e more heavily marked secondaries, prompting us to count only nine "white" secondaries in some specimens. We ne\ er found a specimen with only six or se\ en of what we would judge to be white secondaries. Wing patterns of T. hrachyptcrus and T. Iciifoi cplhilus were indistinguishable from those of 7, pin(i( lidniciis. Sexual dichromatism ni shadmg patterns may further complicate these patterns. In the 7". hnuliyplcnis we collected, we found a dark termi- nal spot on the t)ulermost (first) secondary in nine often females, but this mark was absent m all 1 1 males. Lastly, we doubt that this technique could be aliempted effectively with dried skin speci- mens, because of reduced access to the secondary remiges. Fresh tlowns \oung are identifiable to species using characters of the head patterns of the natal plumage. These differences were assessed by 1 himphrey and Livezey (1985 ), work based in turn on ihe earlier diagnoses presented by Fowet 1934) and Murph\ ( 1''36). Briefls. dowiix xoung of 7. / STEAMER-DUCKS (ANATIDAE: lACHYERES) 69 t/j o ^ _aj sz Xi u ,^ c^ f- (U O I c5 Ci u ^ s — n S Q. £ I < M,2 Q. S u. OS . < -J UJ Q u- z =1; ^(j ~J ~y ■^ ^ I ? ■: _c ^ SI f- 23 X r: iu '$ X o ^ -^ '-< -; 5 o ^ _ji ir 5 c -2 o OJ > It IJ 1J 5 o fj OJ o i o "7 1- y: ^ ■r- X. ^ JZ 1„ ^ -? f~. ^ 5 s ; specimens of flightless taxa exceed this value flightless Tiuhycrcs (Table 5). especially if used (Table .^). The ratio of wing length to tarsus length in combination w ith a measure of si/e (e.g.. tarsus puis itics smii lar separation of the iwogiotips (Table 78 UNIV. KANSAS MUS. NAT. HIST. MONCXiRAPH NO. 8 Fig. 21 . Dislal ends of carpoiiietacarpi ofTcn li\cic.\. lateral surlaccs. showing the pointed niaignis ot'thc,si(/( m.v tciulineiis (ST; .stippled) in 7 hniLlixplcius and 7 Iciicocepluiliis: A — T. palcichoniciis (KU 79205). B — T. hruchyplciKs (KU 8().'S27). C— 7'. Iciu (n cphciliisiKV 7792.5 1. and D— 7. plciwrcs (KU 79S42). Fig. 22. Distal ends of radii of Tachxcrcs. showing the comparati\el\ large, appressed seapholunar facet (stippled) of T. lemocephcihis: A — T. patachmicus (KU 7920.5). B — /'. hraclnplcnis (KL' S()527). C — T. Iciiioccpluiliis (KU 77938), D—T. pieneres (KU 79842). ,5, Fig. 24), IS measured iiioic easil>. and can be used with study .skins. Roughly, the wings of T. palachoninis are five titnes as long as their tarsi, whereas the ratios of the flightless species average four: sexual differences were insignificant. Murphy ( 19.'?6) gave the means for the reciprocal of this ratio as: T pieneres. 0.26: T. hiiuhypienis. 0.24: and / putdeluniicus. 0.20. Multivariate analysis of a suite of external measurements provides the most reliable discrimi- nation of species and sexes (Appendix). Using the fourmt)st commonly available skin measurements (culmen length, nail width, tarsus length, ami wing length) in a stepwise discriminant analysis. 71.4% of 245 specHiiens were correctly I jack- knifed) classiHed to species and sex (Fig. 25): this compares favorably to the 12.5% expected for ranilom assignments. If sex is known, species identifications using the same data achieved 91 .5% success for males (« = 1 30) and 90.4% for females (/; = 115), as compared to the random expectations of 25%. This indicates that, for these characters, knowing the se\ of the specimen improves accu- racy of identilication by almost 20% . Inclusion of total weight in the anahses reduced the sample sizes and only slightlv impro\etl the success of species-sex classihcations (79.4'/( success. /; = 131). C'lassitication functions incorporating the four external measurements are gi\en in the Appendix. STEAMER-DLICKS (ANATIDAE: TACHYERES) 79 h- r^, -t 3^_ r J DC •C U-, f"*-. y. r^l _ _ _ ^/". _ — _ r- _ -T _ a: _; o +1 ^, +1 r*'. +1 r^, +1 rr, +1 r \ DC r I +1 ri +1 OC r- +1 r- +1 n £ o yi ly^! r^ ^. sC r- — 3 — U- ^. ^ X r 1 r 1 GO '1- r \ j; -t V, r^, o r^. li^l . — ■ r*', r i Jri +1 r^ +1 r- +1 r- +1 r^ +1 DC +1 -T +1 5 +1 JZ +1 3 r<-, r*-, OC :i •r, vC -t — DC — ri — DC a- ^ — ~' r*-, li^. 1^ -' >r. ^ X. _ DC U^, r^ r 1 _ r-, OJ ri o r t '-^, — -+-I f^, ^ r i r^ +1 IT. +1 >/~, +1 >/~, +1 1/". +1 ly, r^ + 1 — +1 3 +1 o ri -jr. :£ yz 1/-. ■•c -T r. r'\ ^. c^. r 1 -. ^r. -t -t -X. r i O +) y. +1 ir, +\ 'y^, +1 li^. +1 -t +1 »/-. +1 rl +1 ~ +1 y r 1 r- \ r 1 r 1 r 1 s 2 "y*, DC ^ r 1 i' — oc ri -1- ~ — r*'. U", ~ ^ 0-- t ■j: IT", DC r-, *r. _ 1/-, 3^ >:; r- O r i *r. r 1 «/", +1 r3 +1 — +1 ^- +1 r*-, +1 •^' +1 rr, +1 r- +1 ■-o ri +1 ? DC >c '/". r- CJ [-- -f U- DC r 1 ■3^ DO r J r 1 r^. -T ■A ri ^ __; r 1 in; yi r i _aj +1 +1 sO +1 ^ +1 ■sO +1 ^ +1 -1- ~" I — +1 ON r 1 +1 o +1 a-' ^ r 1 DC DC >0 ri OC C OC s ri -r J-. r<-, DC _ _ ^ rr-, 1/". OC r- "-J ri O '-^, yr. — ^d rj ri -^ +1 r- +1 r-- +1 r- +1 li^; +1 -t +1 o +1 ^ +1 »J^- +1 o 1 r i -£ DC ^c rr, >£ rr, DC 1/". "£ DC r 1 ^ O f^i ON -1- r 1 5 V-, ri ■J-. r i i>^! r I r\ o +1 r- +1 ^ +1 »/~. +1 %c +1 r 1 +1 — +1 ■^ +1 — +1 w~. -^ ^ ^c -c sC s DC ^C r^, ^ ^' OC ti-. NC -1- ^ "^^ ^ r^'. O -t ^ — " ri-U -Jj X •Dij O c Z ^ Ci 5 t^ ^ :5 z A a. 7i ^ '-i- ,C <-£ > - O 'i z - < 5 c '■-' c o > O ^ n> o > _c V OJ Q ■t3 O z < STEAMER-DUCKS (ANATIDAE: TACHYERES] 81 T. patachonicus T. I eucocep halus T. br ac hypterus I — I 1 2 CM T. pteneres Fiy. 2?. Dlai;i"aiii>- ol longest (ninth) prniiars and (Hitcmuist (tirsl) secondary remiges oi Icn hycrc.s. illiistratnig I he Uinger. broader (light leathers of 7. paUu luiiiu lis: A — T.pahn limiu ii.s. male ( KU 7')4(il ): B — 7. Iciu at cplniliis. male (Kl' 7'-)24fil: C— / hunhvplcnis. male iKV S()525): D— / piciwics. male (KU 7^)1X21. 82 UNIV. KANSAS MUS. NAT. HIST. MONOGRAPH NO. 8 p -1-1 = +1 w +1 v~. ■ — — ■ ni — ■ r\ — u. o r^i 'f -i — o — c +1 ^ +1 ':: +1 ri +1 vc +1 z +1 s^, -t O — oc — +1 ::£ +1 7, 3C — — — +1 ~ +1 1: +1 X +1 _ +1 •^ — ri — r'-, ^ r^ -+■ — '/". ;;:; +1 q: ^ 5 +1 1^ r 1 7i ~ H V a. o V a. O z -I" c 7Z 'J V. — fl> f.. c X. t- -^ P 7Z X. STEAMEK-DUCKS (ANATIDAE: IMHYKRIiS) 83 6 - in 5 r patachonicus T leucocephalus T brachypterus 66i57) T pteneres 3 9 C^C5,36, ?? (26) SPECIES - SEX GROUP Fij;. 24. Graphs of nie;iiis (horizontal lines), standard deviations (wide vertical bars), ranges (narrow vertical bars), and sample sizes (//) for ratios of wing length over tarsus length for eight species-sex groups of Tachyeres. 40 2 0 < > 00 o < -2 0 -4,0 - 1 1 1 1 1 1 T brachypterus T I eucocephalus 00(I5) ' ' ' 00(I3) (61) -26 -14 00 14 CANONICAL VARIATE I 56 Fig. 25. Plot of eight species-se\ groups of l\uh\cic\ on fust two canonical vanalcs ol lour external measurcniciils; onl\ extreme inJi\iduaK ((.Iclimiling polygons) .nul means (asterisks) are plollcd. Skimh At. Mea.slri-mhnts few wing elenictits ami witlths of linih elciiiciits. interspecific differences paralleled tiicsi/c rankings Tw()-v\a\ .ANOVAs of -^6 skeletal diniensKMis of species produced b\ t(ttal binl\ weight, al- (Table (ii demonstrated significant differences ihotigh magnitudes of the differences \aried among atnong species (f < O.OOOI ) in all but sternal keel meastnements. Wing elements were iiuich more depth (P > (1. 10); intersexual differences were similar in their lengths than would be |iredicted by found in all measurements, males exceeding fe- overallbody size, evidently related to llightlessness males m all {P < O.OOOI ). Except for lengths ot a in three of the species. .Actual reversal in interspe- 84 UNIV. KANSAS MUS. NAT. HIST MONOGRAPH NO. 8 r — DC -t ^ cc ^_ -, '/-. l-l T. JJ — — : r i — .' r^l — ■ (~\ — "* — o — ■ ^ rs +1 ^c +1 O +1 DC O +1 O +1 sC +1 v~. +1 -c +1 -c +1 sC +1 -sC +1 ^C +1 sC 4-1 sC +\ o +1 sc C n — ■ *"" '~' ■ — " r\ " — ' -1; ' — ' q ■'^ oc ■ — ' ' — ■ OC ^^ "-' ^^ ^^ J-- -t 3 r^, r\ - r-\ r 1 ^. J; oc *r. -. -r r*". o +1 :>c +1 3^ +1 oc +1 •C' +1 sC +1 ^ +1 s +1 s +1 ■c +1 •o +1 5^ +1 c^ +1 o^ +1 3 4-1 3 (-~- (-r, yr. 2 " — r 1 yi ■ — " " r 1 " '/". 'r', "^ ■ — ' — ' r 1 "^^ ir. "'"' v~. "~^ OC ' — ' OC ■■^ ■^ r^ ■ — ■ ^. ^. y/-. r i r*", r\ r 1 r 1 -'. -f r'\ >/~. ri OC r 1 rt +1 n +1 r 1 +1 r 1 +1 r 1 +1 r 1 +1 r-l +1 r 1 +1 ri +1 r^l +1 O] +\ r\ +1 r\ +1 r 1 +1 r J +t oi vC r~-^ — -t — '/". — ■ ~ — C: — r-- — — — -f — ^ — — - yr. -— r^, — »r. — ^ — • >c -^ U- r 1 r-' -r sC -t r 1 ri r- ^ ^ r \ 'X y. [^ X. r-. r i '■''. ri r*", 3- ■c. ^' r 1 -T r 1 r~- •^1 r3 +1 +1 +1 -t +1 -r +1 ~r +1 -1- +1 -T +t -t +1 -T +1 -1- +1 -t -t +1 ^ +1 ~t + 1 -r -^ +1 Tj- r 1 2 r 1 ir, r 1 :c r 1 -6 r- '4 ^ "/-. ri r i ■XL r 1 r-' r-' -' y- r i yr. r^, y: ri ^ 1 r 1 -T -; -: - f. — r ) •-^1 +1 +1 +1 :5 r-~ +1 r^ -fl r~- +\ -t + 1 -t 4-1 -T +1 -f +1 -t + 1 -t -f +1 r- +1 [~~~ +1 r-- •^ 4-1 "T p DC r 1 X >: r 1 r 1 -r r\ r^ '/-, -' OC r I w". 'y-: ir* =. -t- r^, rr, r-"! ^r, =. 'r. *r. r 1 r- r^, n; rj +1 S" +1 c? +1 s^ +1 T. +1 ty^. +1 yr. +1 -T •r, +1 '/-, +1 r! ^ r-'. '^■ r^ -t sC' ~ l/~, n-, y- - r*", r^, r*-, ri C^. ri r i X r»-, i>^! "t; '-» +1 +1 +1 tr. +1 -1- +1 ^ O^ +1 C^ +1 O^ +1 3^ +1 c> +1 C^ +1 a^ +1 •^ +1 -t- +1 -^ 3^ +1 -i- r3 ■^ >rj n «/". *-> :5 S ^ y -(£ \^ z: —J ^ o /^ ;/: U- H i~; STEAMER-DLICKS (ANATIDAE: TACIIVt-RIS) 85 — r I +1 + 1 £ +1 -C +1 + 1 vC ~ a- ■^' =- +1 — I~- — r^ + 1 3- +' c^ +1 3~ +1 ~ ^. - T. - ~ r 1 'r, — ■ r 1 r i + 1 rl I/". ■ +1 ri +1 r) +1 ri +| n +| ri +| n +| n +| .- 1 +| ^. ~ r*-, ~ r^ ~ r<-, ~ sC ~ nO 3 o^ w "1" ^ X r^! >C -t O^' O-' >■•-, — — I/-, r^ *" I -c "^ I cr 1^. '^. +1 +1 -t r I — + 1 ^ 4-1 -t +1 r 1 — +1 _ ^' _ +1 r~~ +1 r^ +1 r~~ +\ o~_ ■ — '^: ~~ ^ "- r^. r I o +1 r-~ +1 r- +1 1^ +1 r- -t-l ^ +1 ^ +1 ^. — ~Z r^. "Z^ r~~- o^ _r^ r^ _0 _ O^' -t C a-' -T O O f I ^ '"'■, j" '"^. '■^i r~~ — -^1 — _ — ri— r^, — — — .^ — +i C- +1 3^ +1 + 1 -C +1 ri +1 U- +1 ^1 r, ri +1 ri ri 3 — 3 ^ 3 — r I — r I ■r, r-- +' DC +1 X +1 OC +1 30 +1 OC +1 »3 +1 X +1 X +1 X -H X CJ — 3^' X 3 [-■ -t — T. «C r i sC r I ^. V", -I" I/". '/". -», ^/". r 1 _ — _ +1 -r +1 -1- ^; - - - + 1 ^C +1 vO ^ E u H o U t/5 — o 86 UNIV. KANSAS MUS. NAT. HIST. .MONOGRAPH NO. 8 h-; u +1 t +1 '^. +1 22 +1 J. sC r^ O _ +1 ^ +1 2 +1 2 ^ sC ^ i^. ^ r-~ ^ n r I C _ — _ — +1 nC +1 vC +1 vD +1 vC nl; -M St; -M vu -M ^^-^ ^[ ^»^ -ri 'i^ -ri >i^ -ri ^i> ^ +1 sC +1 -C +1 vO «-. - ^, _ -*. _ 1^, rj r— _ 3C ^ 2 — ri O +1 C +1 ;^ -M ;^ -M ^j ^1 O +1 O +1 O +1 C — I/". O^ _ U-, ^ rl _ 3C _ 3- „ J t' c-^ ■/-'. s*^ /"I I/". (-1 +1 -r +1 -r +1 r^. +1 •* n — +1 U "•"' H "•"' 2 "•"' 2 _,_| r^. +1 ri +1 rj +1 r2 ^ ri +1 r^ +1 r^ +1 >^ tr. r I — rl — +1 ri +1 ri +1 >i^. ^ r^ — — ' c — o' r^i -ri '^1 Ti O +1 — _(_| — +1 — ,C 1-1 +1 £ +1 -T _ C> sC vC T| CIC +1 X +1 1/-. +1 OO Ti _ O ^ ri ^ — _ +1 OC +1 oc r^ X ^- -C 73 a. c V. L> -> oj 0^ *^ STEAMER-DLICKS (ANATIDAE: TACH)I:RI:S) 87 L'ilic rankings, wherein sni;ill '/'. pahu lumn us had greater mean ineasurements than the laij;ci flightless species, oeeurs in lengths ol the ulna and radius. As a result, simultanedus eonsideration ot sueh wing element lengths and a more si/e-re- lated element (e.g.. sternum, femuri is et't'eetive tor distinguishing 7. pauu lu>nu us from the flightless species. Lowe ( 1434) illustrated the dil- t'erence in relative lengths ot the humerus and sternum between T. patavlumu us and 7. piciicics (his hiavhypterus). Another anomaly occurs in w idths of limb elements, in that T. Icucmcphalus has consistently wider, more robust limb bones than its larger relative T. hrachxpicrus (Table 6). Overlap exists between species in all measure- ments, but selected combinations of characters — e.g.. ulna length, femur length, and humerus head w idth — would be et't'eetive for species identirtca- tion in many cases. A few of the measurements are less reliable because they are influenced some- what by age. even after fledging; sternal keel length, sternal keel depth, and antorbital and interorbital widths of the skull. A particularly effective criterion for distin- guishing T. putaclumuus from the three flightless species is the ratio of humerus length to femur length (Fig. 26). Flightless Tcuhycics have ratios below 1 .6 and ratios for T. pahu haiucus lie above Ihis \ alue; onl\ I skeleton in 148 violated this rule (a male 7. Icuca cpiuilus had a \alue of exactly I (il ). Mean values for this ratio are as follows: T. ptikicluiuicus. I.6M; T Icuvovcphalus. l..'S.^; T hi tn Inpierus. \ .52: I\ pieiwrcs. 1.47; sexual dif- ferences within species were not signihcant (d.OS < P<().7I ). The relatively robust limb bones of T. IcuKH cpliiilus are most clearly shown by the ratio of the least width at the midpoint of the shaft tli\ idetl by the length ot the element; limb bones of r IciH lu cpluilus are either the most robust in ihe genus (humerus, femur, tarsometalarsus) or equaled only by those of T. piciwirs ( radius, ulna, tibiotarsus). Except for the radius and ulna, these ratios of robustness" are made more useful by the lack of significant intersexual differences within species (/'> 0.15: Table 7). Another ratio useful for distinguishing T. Icu( (Hcphalus trom other Tacliycrcs is posterior sternal width divided by sternal basin length, 'sternal flaring" (Table 7). InterspeciHc differ- ences in this ratio (log-transformed for ANO'VA) were highly significant {P < ().()()() I ); intersexual differences were nonexistent (P > 0.73 ). The com- paratively great sternal 'flaring "in 7. Icimn cp/uilus was noted qualitatively and illustrated in the de- scription of the species (Humphrey and Thomp- son 1981 ). Overlap between 7'. Iciuat cplnilus and the three other species is minimal. L'sing 0.72 as 1.9 1,7 16 - I 5 1,4 13 T potachonicus T. leucocepholus T_ brachypterus T. pfeneres -i-ies HHies <:^d(55) 00(46) ** -^153 -i-152 66{Z0) JJ(I7) dd(l4) 92"2' HH47 HI- 147 66{\B) JJ(I6) SPECIES- SEX GROUP Fig. 26. Graphs of means (horizontal lines), standard deviations (wide vertical bars), ranges (narrow vertical bars), and sample sizes (/i) for ratios of humerus length over femur length for eight speeies-sc\ groups ot'Tachyeivs. 88 UNIV. KANSAS Ml S. NAT. HIST. MONOC.RAl'H NO. S +1 £ +1 S +1 !C' +1 £ +1 £ +1 U. >c' >c' -t :x. 'i :^ +1 Z +1 ~ +1 i +1 _ +1 i: +1 X. +1 -c— — — vC — -r — r 1 +1 Z +1 Z +1 Z +1 U-, — ^C "— (^ ^ >c o vc -T x; f^. — Z +1 +1 _ +1 Z +1 Z +1 _ +1 r 1 r 1 i~ I '/". +1 P. -H ""■ W", +1 rj +1 :l: +1 i: +1 1: +1 :i: +1 i. 0-— o— o— ON— ^— -c— -t — vd r-^ i/"i oc -T c^' ""^ — ir, o — c +1 :^ +1 +1 11' +1 f^. f^, +1 ± +1 :j +1 ij +1 II +1 = +1 ij +1 r, +1 :;;: +1^+14 +1 7, +1 4; +1 ^ +1 7, r*-, — — — r<-, — ir. — r-— sC— S' — vC ^c -f :c -r 3C "^ J= — . a: f- H J5 I o c A > ^1 y. u _: o r: c: ■— "' o o '— :— X: J= X -3 r3 '-> y ^ ^ ji E > ^ '- - ~ II ^ 2 "i I I ,H ■5 -i = -^ -c J5 c O fi -o 0 '!=■ ^ • '-J ;y _ y. "■ -3 _ -^ ■ — ?: -^ 1> '■'. T H c - o 1> \/ i> rt OJ =U 0 r: •r x: I x: - y >^ s c -= =u +1 5 =- n x; STEAMER-DUCKS (ANAIIDAE: lACHYERES) 89 a di\ uliny \ aliic lor ihc ralm (sc\os pooled). onl\ 4 ol }h (ll'() '/. U'liciHcplhilus tall hclow this \aluc. vNhoreasonly 5 of 102(3'/( ) I .pahuluiiiuus. 2 ol 2fi (S'i ) T. hrmhypicnis. and 1 of 33 (39; ) /, pli'iui'cs fall aho\c it. Mulli\ariatc disLrimination of complete skel- etons is exiremeh powerful (Fig. 27). Stepwise canonical analysis, using 14 of 36 skeletal mea- sLnenients, coiiectly identified the species aiitl sc\ of MS.S"^/ o\ 16.^1 ciMiiplete skeletons in jackknilcd classitications; the two errors inclassilication were small missexed specimens of '/'. paiiu iwnu ii\ and T. hracliyptcms. Variables and classification coct- ticients are gi\en in the Appendix. F-^ir fewer mca- surenients arc needed to achieve classification percentages approaching those for these "optimar models (l-jg. 2iS). Classification percentages of complete skeletons to species and sex exceeded yO'r using only six measurements and reached y.^' ( incorporating 10 variables. If sex is specified, species identifications using optimal models were completely successful for both males (;/ = '-)(!. I') variables usetl) and females {n = 15. 10 variables used). Limiting the analyses to single sexes per- mitted greater reductions in the number of vari- ables needed to classify. For males, species clas- sitications were 97.S'y correct using onl\ two measurements (lengths of the femur and ulna); species identification of complete skeletons of females reached 94. 7'; success using two mea- surements (least sternal w idth and w idili >)t ulna at midpoint ). Partial skeletons. v\hich t\picall\ rcsiili from preparation of stmh' skins or the salvage ot tlam- aged carcasses, lack skulls and distal limb ele- ments and are less successfully identified. Idenli- licatioiiof 199 partial skeletons using 10 of the 13 available measurements was 91.7'/( correct. Clas- sification functions are given in the Appendix. If sex is known, successful identifications of species increased to 96. 3"^; for males (;; = IO(X. 9 variables incorporated into model ) and 100'^^ for females (h = 91. 7 variables). As for complete skeletons, much simpler combinations of variables are nec- essary to achieve reliable classification of partial skeletons of known sex. Determination of species for males exceeded 9()Vr using only three vari- ables, and surpassed 95% based on five measure- ments (Fig. 2S). In jiarlial skeletons, only two measurements (femur length and posterior sternal width) were needed to achieve 95.6'/( success in species classification (Fig. 2S). H 6 UJ 1- < 4 cc < > d _l < tJ 0 z o z ~y < o n r -I r T. pteneres CXMI6) T leucocephalus T. pat achonicus -I L. _l L -10 -6-4-2 0 2 4 CANONICAL VARIATE X 10 Fig. 27. Plot of eight species-sex groups ofTtirliven's on first two canonical variates of 1 9 sl^clelal nieasiirLMiienls only extreme individuals (delimiting polygons) and means (asterisks) are plotted. 90 UNIV. KANSAS MliS. NAI . HIST. MONOGRAPH NO. 8 100 U- to C/5 < -J 9 '':< o >- _J 1— 80 bJ CC q: o o 70 Ld < 1- 60 CJ cr 50 females males both sexes I 2 AV f emoles _!_ _!_ 8 9 10 3 4 5 6 7 8 9 10 19 \ 2 ' ■• - ■ NUMBER OF VARIABLES INCORPORATED Fig. 28. Classiticaliiin percentages lor increasing lumihers ol measurements available lor complete and partial skeletons; analyses of males, females, and sexes combined are plotted separately, and terminal (ended) pt)ints ol each curve reprcsenl optimal, backstep-selected motlels. KEYS TO IDENTIFICATION OF SPECIMENS Skins Downy Yoi^nci The followini; key, after that given by Humphrey and Ijvc/ey ( IMS.^ I. is applicable to class-1 dov". nics ami. perhaps, to earl\ class-il dounies retaitiiii!: clear head patterns, t'haiacterisiic head patterns ol' the tour species vserc ilkistratetl by lluiiipliivN atid Livezey 1 1 48.^ ). la.Uppcrcyelul \\ hitish; ctinvn tlarker than checks; .supraloral ami supraoculai patches u idc and con- tinuous \\ ith v\ idc jiostocular streak /. IclK IK CplhllllS lb. Upper eyelid tlark; crow n not darker than checks 2a.Postocuiar streak divided: supraloral ami supraocular patches very small or abseiil. ami scparalc uhen present T. picncrcs 2b.Postociilar streak uiidi\ided: supraloral and sti|iraocLilar patches present .^ .^a.Supralor;il and supraocular patches very narrow (almost occkkled anteriorly ). continuous, ami separateil Irom postocular streak T. paldchoniciis .^b. Supraloral and supraocular patches narrow and continuous with postocular streak T. hnninplt'ius F-i i:ix;rD Birds .•\ge- telated changes in bod\ mass, colors ol solt p;irts. ant! plumage pattern piechKle the presentation ol qualitative ami mensural diagnostic keys tor skins STEAMER-DUCKS (ANATIDAE: TACHYERES) 91 of fledged specimens o\ all species of Tinhycics. 4 kgand nail w idlh usLially 14 mm or less: limited Accordingly. qualilati\ e chaiacieis in the ke\ gi\ en to coastal environments of C'hubut. Argentina or below are representative only of adults indetinitne the l-alkland Islands 3 plumages, whereas mensural characters apply to 3a.A/(//c,v indistinguishable externally from 3b; fc- birds of at least one year of age and not in wing molt. iiiukw \\ ith postocular streak becoming indistinct posteriorly; endemic to the marine coasts of the la.Ratio of wing length to tarsus length generally lalkland Islands T. hrachxplcnis exceeds 4.."^; wing-loading usually less than 2.5 3b. A/ coastal Chubiit. .Argentina T. Iciudccpluiliis .lb. Ratio ot sternal caudal width to sternal least width usually less than 0.72; scapholunar facet of radius not expanded; endemic tocoastal en\ iron- ments ot the Falkland Islands.../, hnnhyptenis FIELD IDENTIFICATION Introductory Comments The s|ieciesot'steamer-duck are so similar to one another and ha\'e such a complicated array ot molls and plumages that it remains very difficult to detini- ti\ ely characteri/e any one of the species using only field marks or external characters. Historically this caused a great deal of trouble for museum taxono- niists and continues to be a problem for field orni- thologists who wish to make identificaliims without collecting specimens. These difficulties have troubled a number of ornithologists who have tell that it was inappropriate to ilescribe a new species of flightless steamer-duck (/'. Iciicoi ci'luihis) which, it was felt, might more appropriately have been considered simpl V a subspecies ofanolherpopiilatioiU)f II ight less steamer-duck (e.g.. 1. piciicrcs or T. hrculnpicrus): evidently the notion was. we judge, that "big" birds that look alike and have allopatric distributions cannot be ilistinct species. In many respects, the crNjitic species of /<;(■/( \'(7c,v are comparable in diflicult\ to tiie Eiupiil h),^6. McWhan 19.^2. Wellcr 1976, l.ivezey ami llumphre\ I98.^a). Intensive territori- alit\, both intraspecilic and toward olhci species, is STEAMER-Dl K'KS i ANATIDAE: TACIIYrRl S) 93 charaLtLTislic ol Iik li\cirs. the e\(iliilioiuM\ iiiipli- calions ol w Inch ivniaiii cunlroxciMal (Livc/cs aiul Huniplircy |yiS5a.b;Nuechteileinand.Sioicr I^S.^a. b:Murray 19X5. I9S6: Live/ey 19S7a); MaLDimagh ( I'-MI )piesenlei.lanearl\ discussioiml icii iloiialil> in Uiyhlcc! and tliyhlless hiclncivs. Nonbrcedmg adiills aiul suhadiilt buds frequently are encininlered ni laryc. otlcn e|uarivlsome tlocks near shorelines not occupied b\ territorial pairs. All species ot Tachxcrcs t'reqiientl\ di\e tor food (Weller l9A4a. Livezey I "-'SSa I. and all t\ picall> nest on the ground (Weller |y64b). although members iit several spe- cies ha\ e nested in natural or human-made cavities (lluniphre\ and Livezev 19S5). Fl\ iiig Steamer-ducks are more \ aried in habitat than their llighlless congeners. On marine coasts of Tierra del Fuego and Chile. T pahuhanh iis occurs more frequentK on open beaches than 7. pivneics. which instead frequents rocky shores (Live/ey 19//;A-!,';v'/hA:"" he also altributed a cdiuunent "'click- ing sound" to the female. Weller noted that paired 7 hnuhyptcnis \iKali/ed synchronously durini: terri- torial defense, the males intensifying their calls in tandem as hostilitiesescalated.Neuchterlein and Storer ( 1985) described such territorial "duetting" between mated T. patavhoiiicus. and presented the first sonogram ofvocalizationsforthe genus; this sonogram depicted "Groans" and "Gmnts" by a lemale. antl ■"Rasping Grunts" and an extended bout ol '"Tickuig" by a male. Fjeldsa and Krabbe (lW():i:()) described the vocalizations of territorial male T. paiavhonnus as "...long series titididididi.... luiirr liuirr liiiirr.... hr- hi-hr.... and engine-like toc-toc-toc... alternating with loud whistled hzlicco. Also low cackling iiiii- and kck kck. Calls Ikcc." Vocalizations ol all four s|iecies ot liuhycics were recorded in the tield by Roberto Straneck. copies of which he generously gave to us. Conci.sely summarized, most vocalizations of steamer-ducks are associated with territorial disputes and therefore are agonistic in nature. In all four species (F-ig. 29): ( 1 ) males give ""Rasping Grunts, "" descending, rasp- ing calls which are comparatively lower in fre- quency and prolonged in T. picncics: { 2 ) males often follow ""Rasping Grunts" with bouts of ""Ticking;"" (3) females often duet with males (particularly dur- ing bouts of ""Ticking"! with deeper ""Grunts." often preceded by a few deep, more prolonged ""Groans"" (Nuechterlein and Storer 19S5). The vocalizations of Tiichycrcs deserve special attention by future workers, particularly with respect to behavioral ecol- ogy and interspecific (.litferences. STEAMER-DUCKS IN CAPTIVITY Steamer-ducks are rarely kept in captivity, not only because of their limited and comparatively isolated distributional ranges, but also because of their aggressive behavior toward a diversity of other species. Livezey and Humphrey ( 1 ys.'^a) compiled a number of records of such interspecific attacks by steamer-ducks; additional targets of aggression by captive Tacliyercs include a Rhea { species not given ). Demoiselle Cranes {Aiitlinipnidcs viri;o). Tasma- nian Native-hens (Trihunyx murticrii). and Crested Screamers (Cluiuiui ron/iiuiu) (Griswold 1968. Schmidt 1969). Todd (1979:162) recommended: "Under no circumstances can these hostile ducks be mixed with any wildfowl (or most other birds), as they would kill them instantly, regardless of si/e." He (p. 162) added, however, that '"...in spite of their obvious temperamental shortcomings, most cap- tive steamer ducks that I am familiar with were extremely endearing." In addition to their aggres- sive temperament, steamer-ducks do moderately poorly in captivity, suffering significantly from disease and proving difficult to breed (Hillgarth and Kear 1979). The first record of a capti\e steamer-duck was one T. hrachypicnis presented by Captain T. Fi. L. Moore to the VJenaizerie of the London Zoological Society on 5 September 1861 (Sclater 1861. 1872. 1877. 1879. 1880b. 1883); this individual of un- specified sex evidently lived for more than 20 years in captivity. Nine more T. hnichypicrus were cap- tured during the expedition by Captain Lecomte to the Falklands during June 1867. but unfortunately none of the birds survived a stonny passage between Port Stanley and Montevideo (Sclater 1868). An additional live specimen of T. hnuhyptcnis was presented to the Menagerie in London by F. E. Cobb on 12 June 1882 (Sclater 1882, 1883). A third and evidently final specimen of 7. hnichyptcnts donated to the Menagerie was presented by A. McCall on 23 June 1888 (Sclater 1896); based on the report by 1 1 ubbard ( 1 907 ). this individual survived for almost 20 years. These two instances of long-lived steamer- ducks indicate that the datum on longevity tabulated by Mitchell ( 1911 :5 14) for7(/(7m'/c,v — \> months — was a substantial underestimate. The Falkland endemic continued to be the most trcquently acquired Tavhycics into the twentieth century. S. Kemp and .\. G. Bennett arranged for four specimens of T. hiiichxpicnis. captiued during the "Disco\ery" expedition, to be gi\en to the Lon- don Zoological Gardens (Seth-Smith 1927). Heinroth (1929) noted the presence o\' "Tachyeres 96 UNIV. KANSAS MUS. NAT. HIST. MONOCiRAPII NO. S >- u z UJ 3 o lu cr. T patochonicus IK K n| fit I I I I I I I T brachypterus A. I K T 1 1 1 1 1 \ \ 1 1 [ \ 1 1 1 1 1 1 1 ^"' 17 «-, T I eucocephalu s A. B iin ! I , 1 3- 1 M M n 1 1 \ • 111 I'll ( > I I I 1 I I 1'^ H X >: i H h ,_. T pt e neres - A. 3- ^^^^ male female /A ,i^ 1 ( i > .r,> j^j:^ i^ta _L-I_ -1 — p-^'-'T mole female ,1 I .1 I I 'I •!!! \ ' ■' fc^i kn^mk. ...^\\\\\\\\\:- 'f^ f^ ^ Fig. 29. Sonograms of Tachyeres based on recordings made in llie liekl by R. Stranect.: T. pcikichoniciis — (A) "Rasping Grunts" by male (Bahia Lapataia. Tierra del Fuego. Aigeniina. January 19SI ). (B) "Ticking" by male (l.aguna los Escarchados. Sania Cru/., Argentina, November 1981 ), (C) "Cirunls" by female (Laguna la Nevada. Santa Cruz. Argentina. November 19S1); 7'. piciwics (Bahia Lapataia. Tierra del Fuego. Argentina. January 1981) — (A) duelled "Rasping Cirunts" by male and "Grunts" by female. (B) duetted "Ticking" by male and "Grunts ■ by female; /, hnu liv/ncnis (Carcass Island. Falkland Islands. December 1978) — (.A) "Rasping Grunts" by male. (B) "Ticking" by male; /, iciiviHcphaliis (Fuma Tombo. Chubut. .Argentina. November 1982) — (.A) "Rasping Grunts" by male. (B) "Ticking" by male. (C) '(irunl^ ' by female (in distance). (•//u'/c/rs" al the Foinlon Zoo. ;iiul Dclacoiu ( 14.^4) U.).^2). bill il (.IkI not survive (,\non\moiis 19.^1. reported that Ihrce pairs ol"/ /'/!/( 7;\/)/(77/.v reached Sladeii I'J.'S^). Spcciniciis of /. hnnhypicnis ac- Englandiii 1928. oneof which vvassenltotheaviary quired during the next decade (e.g.. .'Xnoiiynious at Cleres. France, by .S. Lewis and where the birds 1957. Johnstone 196S) led to successful breeding in hvedforsevenyears.Anolherlemale7./)/<;(7n7)/('y((\ captivity at zoos in Duisbuig. Cicniiany (Ciewalt was brought to the Wildfowl Trust. .Sliinbridge. 1968). Zurich. .Switzerland (Schmidt 1969). and the England, by W. J. L. Shuien (.Xnonyinous 19.50. Wildfowl I rust, lingland (Johnstone, pcrs. conim. STEAMER-DUCKS (ANATIDAE: lACHYERES) 97 1 1 9(i,S I /; Schmidl l^^; Jiihnstonc 1470). The ducklings hatched at the Zurich Zoo were though! lo be possible hybrids between T. ptcncrcs and / hnichyptcrus. but errors in the plates by Scott in Delacour (1954) appear to have caused the contu- sion (Schmidt 1969): no hybrids among species of Tachyercs are known (Scherer and Hilsberg I9,S2). Efforts to breed T. hnichypterus have continued ai the Wildfowl Trust for more than a decade since. Willi variable success (.Anonymous 1973. 1974. 197S. 19S2. 1983. 1984. 1985. 1986. 1987, 1988; Kear 1974. 1976. 1978: Lubbock 1979. 1980. 1981). A female 7 hnichyplcnis held at Sea World. San Diego. California (Todd 1979). was the subject of study of diving behavior in Tachyercs (Livezey and Humphrey 1984a) and appeared in a program on flightless birds entitled "Birds of Paradox" pro- duced by the British Broadcasting Corporation. The Magellanic Flightless Steamer-Duck has occurred even less frequently in avicultural collec- tions, although T. piencres were kept in captivity for use as decoys by Fuegian natives ( Bridges 1 948: 1 03 ). Morrison (1940:249) mentioned his involvement with a "collection of live Kelp— Geese {Chlocplur^a liyhrulii]. Steamer-Ducks, and Penguins" during a visit to southern Chile. T. ptcncrcs was listed as a "needed" species at the Wildfowl Trust during the 1950s (Anonymous 1950. 1958). Delacour ( 1954) reported that two T. ptcncrcs were brought to his aviary at Cleres in 1939 by A. Morrison from south- ern Chile (see Morrison 1940): one died soon after arrival and the other "...was in excellent condition until the invasion of June 1940" (Delacour 1954:273). In .lul\ 1962. the Philadelphia Zoo received an "immature" male T. pteneres. and an "adult" temale ol the same species was acquired in January 1964: these birds were successfully bred in 1967 (.'\nt)ny- mous 1967. Griswold 1968). Additional live speci- mens of steamer-ducks identihed as T. ptcncrcs w ere acquired by the WuppertalerZoo. Berlin ( Bock 1973). the Wildfowl Trust (Kear 1977: Anonymous 1978. 1983. 1985. 1986. 1987:Lubbock 1979. 1980). Sslvan Heights Waterfowl. Scotland Head. North Carolina (J. Ballance. pers. comin. ). and the Detroit Zoo. Michigan ( T. Schneider, pers. comm. ). There is some doubt about the species identity of the captive "7". ptcncrcs" in American collections: photographs of the birds in North Carolina indicate that they are instead T. hnichyptcrus. Not surprisingly, the recently described T. Iciicovcphahis of coastal Chubut. to our know ledge, has not been kept in captivity. It is more noteworthy, however, that the most widespread member of the genus, T. patachonicus. also has never been ac- quired for avicultural collections (Delacour 1954), although the statement of Hillgarth and Kear ( 1979: 142) that "...Tachyercs patachaniciis has not bred I in captivity]. .."suggests otherwise. The greater mobility of the Flying Steamer-Duck probably has enabled it to elude capture more easily. It also seems likely that the absence of T. patachonicus from aviaries, especially during the early collecting expe- ditions to the Falklands in the late nineteenth cen- tur\. contributed to the widespread reluctance by taxonomists to accept the existence of a flighted species of Tachyercs. PROSPFXTS FOR THE FUTLRE At the time of this writing, populations of all four species of Tachyercs appear to be secure. T. ptcncrcs and / hi ai hxpicrns are particularlv numerous throughout much of their respective ranges, al- though the former has become uncommon in the northernmost parts of its range iChiloc and northern Bahi'a de Ancud). The comparativelv w idespread T. patachonicus is decidedly less common than its Mightless congeners in areas of svmpatry. aiul the status o\ T^ patachonicus in the Falklaiul Islaiuls is inadequatel V know n. In one respect, the broad distn- bulional range of T. patachonicus renders it less vulnerable to threats to its continued existence. However, until the population structure and possi- blv underappreciated taxonomic complexities of 7". /)(;fc;(7;(Vi;(7/.v are better understood! Li ve/cN 1986b. Corbin ct al. 1988). the possible threats to its differ- entiated, possibly reproductivelv isolated compt)- nents cannot be assessed. The species of steamer-duck tleserv iiig the most vigilant monitoring is T. Icucoccphahis. This spe- cies IS not onlv the most recently described mem- ber of the Anseriformes. it also has one of the most resiricled distributional ranucs of anv continental 98 IMV. KANSAS MUS. NAT. HIST. MONOGRAPH NO. S species of w alert owl. The \ ulnerabilily ol / Iciwoccpluilus is niagnilied b\ its Hightlessness. non-migrator \ habits, aiui strictly coastal distribu- tion. At present, the population otT. Icucinephalus appears stable and. at least locally, the species is abundant. .Shipping and coastal oil retineries. ht)\v- ever. are increasingly common acti\ ities in coastal Patagonia, and the threat of oil spills to coastal birds is substantial. In tact, oiled seabirds and signiticant associated mortality already have been observed in C'hubut (Jehl 1975: pers. obs.l. A single major oil spill in Chubut could directh threaten a signiticant proportion of the total popu- lation ol"/'. Icniin cpluiliis and endanger its benthic food SUJiplN. A number of compelling problems remain con- cerning the ecology and evolutionary morphology of steamer-ducks. Basic data are lacking on the migration, winter distributions, and possible repro- ductive isolation of T. pakiclioiilciis breeding on freshwater lakes. Even less well known are the 7'. paiaclioiiiciisodhe Falkland Islands: the few avail- able specimens and geographic isolation suggest that this insular population has differentiated mor- phologically from its continental counterparts and may be deserving of species rank. Although some headv\ay has been made in the study of the molts anil plumages of steamer-ducks, much remains unknown: particularly poorl\ understood are the predetinitive plumages of all species (particiMarly of 7. /)/c/?('/c.v) and the evident geographic variation in the aspects and possible number of definitive plumages of 7. pani< liDiiiciis. Our understanding of Hightlessness in Tachycrcs would be improved sig- nificantly by a quantitative study of the ontogeny of the hod>' and pectoral girdle in yomig of known age in both flighted and flightless steamer-ducks. The extreme territoriality of steamer-ducks pro- \ides an unusually promising opportunits tor the stutlv of thisecologically important beha\ ioral phe- nomenon, the implications of which remain contro- versial (Live/ey and Humphrey lys.'ia. b: Murray liJS.S. 1986: Neuchterlein and .Storer 19S.5a. b: Live/ey IMSVl. Particularl\ intriguing questions concern the temporal ami spatial stabilit\ of territo- ries (especially in tidal habitats and near islands with high nest-densities I. the ecological and evolu- tionary implications of interspecific aggression, the ontogeny, sexuality, and seasonality of territoriality, and the impact of territorialilN on population densi- ties and dispersion. The open habitat, low mobility, extreme pugnacity, and conspicuousness of steamer- ducks, especially flightless species, and sexual and age-related differences in plumage aspect, make steamer-ducks particularlv appropriate subjects for the stud\ of territorialit\. The tameness and abun- dance of 7, hiiit lixpUTiis. and the likel\ ease with which both sexes could be attracted into live traps for marking by playbacks of calls ( VVeller 1076) or ilecox s. qualif \ this species as probably the opti- mal member of the .'Xnseri formes f(M' the stutl\ of territorialitv. SUMMARY A systematic review of the four species of steamer-duck {'I'achycirs). a genus of benthic-di\ - ing tadornine waterfowl limited in distribution to southern .South America, is presented. Four species are recognized: Flying Steamer-Duck iT. piiniclionicii.s). Falkland Flightless Steamer-Duck (7. hiachyptcrus). Magellanic Flightless Steamer- Duck (7'. pii'iicrcs). and White headed Flightless Steamer-Duck (7'. Iciicovcphaliis). The monograph has six major objectives: ( I ) to present a history of study of the genus: (2) to provide generic and specific synonymies and species accounts: (.^) to describe the molts and plumages of steamer-ducks: (4) to present diagnostic characters and keys for identification: (.5) to summarize infomiation on field iiientificalion anil a\ iculture of 7<;(7;v(V<'.v; and (6) to present an indexed bibliography for the genus. The ornithological history of the steamer-ducks spans foiM' centuries, and is divisible into four major periods: ( 1 ) carl\ descriptions by e\iilorers and natiualisis ua. I.'>82-18.''()): (2l debate concerning the existence of Hying and flightless species in the genus ( IS.^l-l').^.^): G) recognition of two (conti- nental and Falkland) flightless species and a Hying species ( 1 9,^6 l')7^)): and (4) discovery of a second continental flightless species ( 1 ^80 to pieseni ). The taxononnc histoiN of the genus reflects, in part, these changing |ierce|itions. further comjilicated by de- STEAMER-DUCKS (ANAIIDAE: TACHYERES) 99 h;itc coiKcniiiig ihe placcnK'iit of liichycirs within the taniil\ and nonK-nclatural (.oiiliision ( in\(il\'iiii; 2? dittLMvnt binoiiiina in seven genera, evcluding misspellings). Complete synonsinies ate given tor the genus ami inehided species, with concise de- scriptions of diagnostic chaiaclers and distribu- tional limits and designation of types. Common names in 12 languages are also given. Knowledge of the molts and plumages of steamer- ducks remains far from complete. History of study of molls antl plumages of '/(/(/ncrc.v is divisible into three eras, closely associated v\ ith changing percep- tions of Ihe systetnatics of the genus: ( I ) era of exploration (prior to I8.M)); (2) era of taxonomic controversy ( 1X30-1 M.^^); and (3) era ot Murph> ( 1936 to present). We niterpret a\ ailable information as supportive of se\eral important hndings: ( I ) /. hnicliyprerus and coastal Fuego-Patagonian T. paliic/uiniciis{nnL\ probably other populations of the latter) have three molts and plumages per annual cycle, whereas, 7 ptcncics and'/". Icucaccphaliis have only tw(x (2) basic pkmiages of the heael and neck in 7'. hnichypicriis and 7". pataclumuus (and probably i. piciicrcs)nK sexually monochromatic and resemble the Juvenal pliunage, and that of 7. Iciicai cpliuliis is sexually dichromatic wherein the female resembles the Juvenal plumage: (3) definitive plumages are attainetl dining molt II in Atlantic-coastal T. patac/ioniciis and (probably ) T. hiinliyptcnis. those of 7'. IciuiHcplkiliis may not be attained until molt IV, and the age at attainment of dehnitive plumage in 7. ptcncics is unknown. Detailed descriptions of natal. Juvenal, and definitive plumages are given for both sexes and all four species oi'Tachycrcs. empha- si/ing topics for which information and specimens are inadequate forconhdeni interpretation. Diagnostic characters of steamer-ducks incliale massive body proportions, colors of pliunage and soft parts, and Hve skeletal characters. .Species of liicliycrcs are distinguishable b\ a \ arietx of charac- ters of plumage pattern and skeleton, most notably by selected ratios of external and skeletal dimen- sions (e.g.. ratio of wing length to tarsus length, or ratio ol humerus length to lemur length). Multivari- ate discrimination of species and sexes is jiossible using discriminant functions based on suites of external or skeletal measurements. Keys to sjiecies of /"(/(/ncTc.s are presented, but idenlilicationof skin specimens of subadull birds ot unknown sex and/or locality may be problematic. Problems oftieldidentihcation of steamer-ducks essentially reduce to distinguishing the smaller. v\ itlespread T. pataclumiciis from each of the mutu- ally allopatric. marine-coastal, flightless species that also occur on inland lakes (more than 1 km from the coast). In coastal Chile and Tierra del Fuego. ( adult ) 7". ptcncics are unique in their large si/e and the orange color of the bills of hotli sc\cs. Distin- guishing T. patachoncius in the held from the two intemiediate flightless species — T hiaclnpicnis (Falklands)orr. lcuc(iccpluili avicullura de Tachycrcs: y (6) presenlar un indiee bibliogratico del genero. La historia ornitoiogiea de ios patos vapores se e.xtiende por ciiatro siglos. \ se la puede dividir en CLiatro periotlos principaies: (1) las prinieras descripciones de expioratiores y naturaiistas (cerca a 1.^X2- IS.^O): (2) el debate concerniente a la exislencia de especies voladoras y no voladoras en el genero ( iS.^2-19.^5);(.^)elreconociniieni(uleclos (continental y de las islas Falkland |MaKinas|) especies no voladoias y una especie volailora ( I ^)36- 1979): y (4) el descubrimiento de una segunda especie continental no voladora 1 19S()-presente). I, a historia taxononiica del genero relic [a. en parte, esle panorama cambiante que es comiilicatlo aim mas por el debate sobre la asignacion de iiniixcrcs ilentro tie la lamila y conl'usiones de nomenclaluia (relacit)nailasa2.^binomialesdirerentesen7generos. excluidos los eirores ile escritura). .Se presentan sinoniniias complelas para el gt'nero y especies incluidas. con descripciones concisas de los caracteres tliagnosticos. limites dislribucionales y designacion de tipos. .Se proveen nombrcs conumes en 12 idiomas. Fl conocimientt) de las mudas y pluniajes de los patos vapores dista todavi'a de ser coinpleto. La historia tlel estudio de mudas y plimiaje de 7(/patricas especies no \ t)ladoras de la cosia marina t|ue lanibit-n ocurren en lagos tierra adeniro (mas de 1 knule lacosta). V.n las ct)sias de Chile y de Tierra del Fuegt). (adullos) /'. ptcncics son unicos por su taniant) grande \ el color iiaranja de los picos en ambos sexos. La tlisiincion en el campo tie 7. pdiacliDniciis de las dos especies STEAMER-DICKS (ANATIDAE: IMHMiRES) 101 no Mikuloras inicrmcdias — 1\ hiachxphiiis (islas I-alkland | Mah iiias] )o T. Icindccpluilus (C'luihiil do la cDsta) — es dilicik y distinguir T. palaclunuciis de T. hrailixptcnis en las costas marinas dc las islas I-alkkuul (MaKinas) prubablcnicntc no es posiblc en la niayona dc cHindiciones dc canipo. Los patos vaporcs no ban sido nianlcnidos en cauliverioeon rrecucneia.pucspresenlantlilieiilladcs en los aviarios debido a su eomporlanilenlo bel ieoso liacia otras a\ es acLuitieas y al parecer sii repioiluee ion cs dil'ieil. La espeeie mantenida eon mayor I'reeueneia. hisiorieamenie \ al presenle. es l\ hicuhxpicnis. F\)blaeiones sahajes tie las euairo espeeies de Tacliyercs al pareeer eslan segLiras. a pesar de que declinaeiones locales en iHimert)s v la amcnaza lalenlc por derramamienios tie pelroleo a las poblaciones marinas i parieularmenlc T. /(■/((■('(■(■/'//(//h.v) justitican est'uer/os para monilorcar y proteger a las poblaciones. Aspcelos imporianics para cstudios t'uturos inekiycn: la diinimica. migraeion. y posible t'ragmentacion genelica de las poblaciones de T. patiuiuniicits (en especial la poblacionde islas Falkland I Mai villas]); intormacion basica concemiente a la muda y plumajes de T. patcichonicus. T. Icucoccplialiis. y espccialmente T. ptfiu'ics: y las implicaiones evoluiivas de la ex- trema territorialidad de los miembros del genero. La literatura piiblicada sobre el genero — que se extiende por euatro siglos y comprende mas de 550 ret'ereneias — se resume en un indice bibliognitico lematico. SPECIMENS EXAMINED •Specimens examnieil inthisreseaicli. w Inch num- bered almost 500. are of several lypes (SN = study skin. SK = skeleton. SK* = skeleton for which exlernal data were recorded. SN/SK = skin and partial skeleton. AN = anatomical or spirit speci- men): when determined, sexes are indicated (M = male. F = female); sexes gi\en in brackets were determined by measurements and/or plumage. Downy young are marked by "d" and birds in Juvenal pliuiiage are indicated b\ "j." InstitLitions holding the specunens are indicated by abbre\ iations immediatel\ preceding the corre- sponding specimen niMiiber(s). and arc as follows: AM = American Museum of Natiual History, New York; BK = Museum of Vertebrate Zoology, Univer- sit\ of California. Berkeley. California: BM = Brit- ish Museum ( Natural History ).Tring. Hertfordshire, England; CM = Carnegie Museum of Natural His- tor\. Pittsburgh. Pennsylvania: CR = LJni\'ersitets Zoologiske Museum. Copenhagen: FD = Field Museum of Natural History. Chicago. Illinois; HA = Museum of Comparative Zoology. Harvard Llniver- sity. Cambridge, Massachusetts; IS = Iowa State LhiiversitN. Ames. Iowa: KU = Museum of Natural Historv. L'niversitN of Kansas. Lawrence. Kansas; LA = Los Angeles County Museum of Natural History. Los Angeles. California; MI = Museum of Zoology. University of Michigan. Ann Arbor. Michi- uan: MA = MiiseoArszentinodeCiencias Naturales. Buenos Aires, Argentina: NM = National Museum of Natural History. Smithsonian Institution. Wash- ington. D. C; PH = Philadelphia Academy of Sci- ences. Philadelphia. Pennsylvania: R(3 = Royal Ontario Museum of Natural History. Ontario. Canada: RS = Royal Museum of Scotland, Edinburgh: SD = San Diego Museum of Natural History. San Diego. California: SW - Southwestern College. Winrield, Kansas: YA = Peabody Museum of Natural History, "^ale Lnixersiiy. New Ha\'en. Connecticut. Tachyeres patachomcl's (222) Argentina RioNc,!iro.— BM 9Q. 1 .27. 10(SN. M). FD (origi- nally Princeton) ■•8847'" (SN. M). Wc/«//k'/;.— LagoNahueIHuapi:BM99.1-27.10 (SN. M). MA l47Sa (SN. M), MA 31523 (SN). MA 36363 (SN. M). Lago Lolog: MA 35051 (SN. F). Zapala. Laguna Blanca: MA 49987 (SN. F). Cliuhui.— Puerto Melo: SW 3532/KU 77940 (SN/SK. M). KU 79450 (SK. M). KU 79479 (SK. F). Rio Pico. Lago No. 3: MA 52486 (SN, F). Lago Fontana: KU 79468 (SN/SK. M). KU 79469 (SN/ SK. F). KU 79470 (SK*. F). KU 79471 (SK*. M), KU 79472 (SK*, F), KU 79473 (SK*, F). KU 79475 (SK*. M). KU 79476(SK*. F). KU 79477 (SN/SK), 102 UNIV. KANSAS MIJS. NAT. HIST MONOGRAPH NO. X KU 79478 (SK*. M). BK 42829 (SN. M). BK 42S3{) (SN. F). BK 42831 (SN. F). Lago Kiiigger: KU 79474 (SK*. M ). Arroyo Verde: FD ••24()4" (SN. F). FD ■■24().5" (SN, M), FD ■•24()6" (SN. M). Cholila: MA (Liiicalaloged. Kovacs No. 77) (SN. M). Saiua Cm:.— Puerto Deseado: SW 3.'i35/KlJ 77944 (SN/SK. M). SW 3.'^36/KU 7794.'S (SN/SK. F), SW 3537/KU 77946 (SN/SK, M), KU 77947 (SK, F), KU 77948 ( SK, M ), KU 77949 ( SK, F), KU 779.'S0 (SK, F), SW 3538/KU 77931 (SN/SK, F), KU 779.32 (SK, M), KU 77953 (SK, F), SW 3.3.W/ KU 77954 (SN/SK, M), SW 354()/KU 77955 (SN/ SK. F), KU 77956 (SK, F), KU 77957 (SK, M), KU 77958 (SK. M). KU 79209 (SK*. F). KU 79210 (SK*. M). KU 79211 (SK*. M, j). KU 792 12 (SK*. F), KU 79213 (SK*, F). KU 79214 (SK*, M), KU 79215 (SK*, M), KU 79216 (SK*, M), KU 79217 (SK*. F), KU 79218 (SK*, F), KU 792 19 (SK*, M), KU 79220 (SK*, M), KU 79221 (SK*. F). KU 79222 (SK*. F). KU 79227 (SK*. F). KU 79228 (SK*.1VI).KU 79229 (SK*.F).KU79230(SK*.M). KU 79231 (SK*, M). KU 79232 (SK*. F). KU 79233 (SK*. M). Ml 157719 (SK. M). NM 5.M266 (SN. M), YA 6400 (SK, M), YA 82326 (SN, F), YA 82327 (SN, F). Ri'o Santa Cruz: MA 52297 (SN. M). Bahi'a de los Nodales: SD 38353 (SK. F). Rio Gallegos: FD '•4697" (SN. M). PH 81 103 (SN. M). Lagiina de lo.s Escarchados: CP791 (SK. M), Ml 220945 (SK. F'. d). Lago San Martin: MA 4288a (SN.j). LagoRoca: KU 79459 (SK*. M). KU 79460 (SK*. M).KU 79461 (SK*.M).KU 79462 (SK*.F). KU 79463 (SK*. M). f\Miio Me)reno: KU 79464 (SK*. M). KU 79465 (SK*. F). KU 79466 (SK*. F). KU 79467 (SK*. M). 7y<'mu/W/-;«',!,'(».— BeagleChannel: AM 443720 (SN, F). AM 44372 1 (SN. F), AM 4437 1 8 (SN, M ). AM 443717 (SN. M). AM 443719 (SN. M). Cabo Penas: BM 1929.6.14.3 (SN, F),SD 37.540 (SN. F). Rio Grande: SD 38645 (SK. M). YA 1 1772 (SN. F). YA11773(SN.F).BM 1932.7.12.1 1 (SN. M. J): RO ( 1 imcataloged fro/en adult male. lo be anatomical specimen. I'rom lake 1 14 km south ol Ri'o Grande i. Ushuaia: AM 44.3729 (SN. M). AM 443727 (SN.1-). AM 443728 (SN. F). MA 5780 (SN. M ). MA 10006 (SN. M). KU 779.59 (SK. M). SW 3.'>41/KU 77960 (SN/SK. M), SW 3.542/KU 77961 (SN/SK, F), KU 77962 (SK, F), KU 77963 (SK, M), KU 77972 (SK, Ml. KU 77973 (SK. Fi KU 79183 (SK, M), KU 79190 (SK. I-), KU 79191 (SK, l-|, KU 79192 (SK, F) KU 79198 (SK, F), KU 79199 (SK. M). KU 79200 (SK. F). KU 79201 {SK. Ml. KU 79203 (SK. M), KU 79204 (SK. F). KU 79205 (SK. Ml, KU 79207 (SK. F). KU 79208 (SK. M). YA82322 (SN), YA 82323 (SNi, YA 82324 (SN), YA 82325 (SN), YA 82330 (SN, F). YA 82331 (SN. F). YA 82332 (SN, M), YA 82333 (SN, F). YA 6485 (SK. M). YA 6845 ( SK,M),YA 8246 (SK,F|, MI 1572()(SK.F). Viamonle: BM 1932.7.12.13 (SN. M, jl. BM 1928.4.21.1 (SN. Ml. BM 1928.7.21.2 (SN. Fi. BM 1932.7.12.12 (SN. Ml. Isla de los Estados (Staten Island): NM 49 101 3 (SK*.M).NM49 1014 (SK*.F).NM511771 (A). NM 51 1772 ( A. F). NM 536349 ( SN. F). NM 536350 ( SN. M ). NM 53635 1 (SN/SK, F). Chile Rc-.^ioii .v.— Corral: BM 96.12.31.7 (SN. F). Valdivia: MA 4883a (SN. F). Chiloe and Baliia de Ancud: AM 443741 (SN. M). AM 443743 (SN. M). AM 44.^744 (SN. M). AM 443749 (SN. F). AM 443766 (SN. F). AM 443755 (SN. F). AM 443753 (SN. F). AM 443754 (SN. F). AM 443759 (SN. F). AM 443762 (SN. F). AM 443763 (SN. F). AM 443740 (SN. M). AM 443742 (SN. M). AM 443745 (SN. M). AM 443746 (SN. M). AM 443447 (SN. M ). AM 443748 (SN.M). AM 44375 1 (SN. F).AM 443756 (SN. F). AM 443757 (SN. F). AM 443758 (SN. F). AM 443760 (SN. F). AM 443761 (SN, F). AM 44.3764 (SN, F). AM 443765 (SN. M), RO 3.5404 (SN, |F1), PH 81097 (SN, M), FD ••3888" (SN, M). Codihue: KU 79840 (SK*. M). KU 79844 (SK*.M).RnsenadalIuito:KU79852(SK*.F).KU 79853 (SK*. F). KU 79854 (SK*. M). Lago Llanquihue: KU 79849 (SK*. M). Lago Rupanco: KU 79855 (SK*. F). KU 79856 (SK*. M). KU 79857 (SK*. Ml. KU 79858 (SK*. I-|. KU 798.59 (SK*. M). R('i;ii>ii XI. — Puerio .\isen (mlerseetion ol Rio Simpson and Ri'o Maihuales): FD "■24()7" (SN. M). Rc:.iio/i XII.— Rio Ciaike: FD 104109 (SK. M). FD 14774 (SN.F).FD 120519 (SN. F): FD 120521 (SN. Fd). I-D 120522 (SN.d). San Agostini Sound: CM 120774 (SN. F). CM 120776 (SN. M). CM 120777 (SN. F). CM 120778 (SN. d). CM 120779 (SN.ill. Pucrlo Chnrucha: H.\l SO. 1 1 . 1 S.565 (SN. STEAMER-DIICKS (ANATIDAE: TACHYIiKES) 103 F). E:ii/alx-th Island: BM 74.9.3. 2S (,SN. F). Puerto Bucno: BM 79.9. .^.29 (SN. F). Bcrlrand Island: PH SI 10.^ (SN. Fl. Wollaston Island: AM 4AMM (SN. F). Navarino Island: .AM 44."W;i8 (SN. M). Straits of Magellan: BM 80.1 1.18.. S65 (SN. F). Falkland Islands Easif-'alkUiiuls.— Cape Dolphin: BM 1940. 1 2.6- 36 (SN. |F|). BM 1940.12.6-36 (SN. M). BM 1940.12.6-34 (SN. F). BM 1940.12.6-35 (SN. F). BM ••86" (SN. d). Bleakei- Island: AM 443785 (SN. M). AM 443729 (SN, M). Fitzroy (Swan Pond): IS I434(SN. M.d). IS 1451 (SN.M.d). IS 1452 (SN. F. d). IS 1453 (SN. F. d). IS 1474 (Sn. F). Unspeci- fied: BM 19.W.12.18.1 (SN, d). BM 1962.1.160 (SK. |F|). UnspcdficJ.— BM 1928.7.21.18 (SN. d). Taciiyeres brachyitervs (69) Falkland Islands East Falklaiuls.— Port Stanley: AM 443791 (SN,F).AM 443782 (SN, M), AM 443785 (SN,M), AM 443788 (SN, M), AM 443784 (SN, M), AM 443786 (SN.M), AM 443783 (SN,M). AM 445783 ( SM,M). AM 443789 (SN.Fl. Diamond Cove: BM 1932.7.2.41 (SN.d).Fitzroy:IS 1435 (SN. M.d). IS 1439(SN,M,d), IS 1454(SN,M,d). Lively Island: KU 805 1 3 (SK*. F). KU 805 14 (SK*. F), KU 805 1 5 (SK*.M),KU80516(SK*,F).KU80517(SK*.M). KU 80518 (SK*. F). KU 80519 (SK*. M). KU 80520 (SK*, M), KU 80521 (SK*, F), KU 80522 (SK*, F), KU 80523 (SK*, M), KU 80524 (SK*, F), KU 80525 (SK*. M). KU 80526 (SK*. M), KU 80527 (SK*, M), KU 80528 (SK*, F), KU 80529 (SK*. F). KU 805.^0 (SK*. M), KU 80531 (SK*, F). KU 80532 (SK*, F). KU 80604 (SK. M ). KLI 80605 (SK. M ). Sea Lion Island: AM 44377 1 ( SN. M ). San Salvador: BM 44.1.18.66 iSN). San Carlos: HA 2204 (SK. F). Mare Harbour (Easi|?| Falklands): BM 1 920.2.74 (SN).Unspecitied: AM 443773 (SN, M). AM 443775 (SN.F). West t'alkUinds.— Pebble Island: BM 1940. 1 2.6.33 (SN. F). New Island: Ml 1 .Vi206 (SK. M). Mi 135895 (SN. M). MI 135897 (SN. M). MI 13589(1 (SN. F). Unspecitied: HA 2206 (SK. M). Uuspccifu-d— BM 1940.12.7.26 (SN. M). BM 1940.12.7.27 (SN). BM 1949.52.38 (SK. M). BM 19,^.0.12.18.1 (SN). BM 1900.11. .30. 1 (SN.d). BM 1900.11.30.2 (SN. d). BM 1900.11.30.3 (SN. d), BM 1900. 11.. 30.4 (SN.d).BM-725"(SN,M,j).PH 55809 (SN, M), PH 558 ID (SN, F), AM 419160 (SN), HA 70521 (SN), HA 70522 (SN); RS 1913.237.82 (SN). RS 1921.143.122 (SN). RS 1921.143.123 (SN). RS 1958.71 (SNs. 5 speci- mens). Tachyeres pteneres (132) ARdLNTINA licrid del Ftic;^o. — Beagle Channel: BM 1929.(-,|4.2 (SN, F), AM 443707 (SN. M). Gable Island: AM 4437 14 (SN, F, j). Ushuaia: AM 4437 1 1 (SN. M). AM 443713 (SN, F), KU 77964 (SN, F), SW 3543/KU 77965 (SN/SK, M), KU 77966 (SN/ SK, M). KU 77967 (SK, F), KU 77968 (SK*. F). KU 77969 (SK*. M), KU 77970 (SK*, M), KU 77971 (SK*, M), KU 79178 (SK*. M). KU 79179 (SK*. M),KU79180(SK*,M),KU 79181 (SK*,M),KU 79182 (SK*, M), KU 79194 (SK*. F). KU 79195 (SK*. M). KU 790206 (SK*. F). Ml 157721 (SK, M), SD 40490 (SK, F), YA 6486 (SK, M), YA 6487 (SK, M ), YA 82235 (SN, M ), YA 82236 (SN, F), YA 82237 (SN, M), YA 82238 (SN, F), YA 82240 (SN, F,d),YA8224l (SN, F, d), YA 82243 (SN. F,d), YA 82244 (SN, F. d), YA 82245 (SN, M, d), YA 82335 (SN,F),YA 82336 (SN,F).BahiaBuenSuceso:NM 5.36348 (SN, M). Lapataia: SD 38646 (SK. M). Harberton: BM 1932.12.14 (SN. M). BM 1932.12.20.1 (SN.d). lsladelosEstados:MA4144a (SN, M), NM 490930 (SK, M), NM 490937 (SK), NM 490939 (SK, M). NM 490942 (SK. F). NM 490943 (SK. F), NM 51 1767 (A), NM 51 1768 (A. F), NM 511769 (A, F), NM 5411770 (A). NM 536349 (SN,F), Cnii I Rc:^ii>ii X. — Chiloe antl Bahia ile Ancud: AM 424579(SN.M).AM 35 I2()()(SN, M),AM 424578 (SN, M ), AM 424580 (SN, F), AM 44366 1 ( SN, M ), AM 443663 (SN, F). AM 44.3664 (SN, F), AM 443665 (SN. F), AM 443667 (SN, M), AM 443668 (SN, M), AM 443669 (SN, M). AM 443671 (SN. 104 UNIV. KANSAS MIJS. NAT. HIST. MONOGRAPH NO. S M ). AM 44367.^ (SN, M). AM 443674 (SN. F), AM 443675 (SN, F). AM 443676 (SN. F). NM 443677 (SN. F). AM 44.Vi78 (SN. F). AM 443680 (SN. F). AM 4437 1 .5 (SN. F). PI I S 1099 (SN. M). LA 24902 (SN. F. d). I-D •■2399" (SN. F). FD "2400" (SN. F). FD •■2401" (SN.M).FD "2402" (SN.F).FD 62419 (SN. M.d). KU 79S3.5 (SK*.F). EnscnadaC\Kliluie: KU 79839 (SK*. F). KLl 70842 (SK*. M). KLI 79843 (SK*. F). Islas (iuailecas; CM 123.S55 (SN. F.d).CMI23556(SN.M.d).FD"2763"(SN,M,d). /?f'.?/VwX/.— Puerto Aisen: PH 16978 (SN. |F1). Punta I.agunas: CM 120850 (SN. F). Region Ml — Muiliroso Bay: CM 123470 (SN. M.d). Almiranlc Bay: CM 123461 (SN. M.d). Isia Hemiite: FD ••4695" (SN. M. j ). FD ••4696" (SN. M. j). MA 42241 (SN, M). Isia Carolina: AM 443716 (SN.M).FalsoCabode Homos: AM446796(SN.M). Cabode 1 lornos: AM 443683 ( SN. M ). Bahia Orange: AM 733420(SN. M ). Isia London: AM 443694 (SN. M). PH 81095 (SN. F. d). 3 unnumbered downy young at AM . isia Wollasttin: AM 443686 (SN. M ). Isia Navaruio: NM 488291 (SK). PH 81102 (SN. |F|). San Agostini Sound: CM 120775 (SN. M). BahiaEden:BM 1903. 12.30.199(SN.F).PH 120816 (SN).PH 120816(SN.M).PuertoBueno:PH 120795 (SN, M). Bahi'a Wide: PH 120813 (SN. M). Isia Newton: SD 375.^) (SN. M ). SD 37582 (SK. F). Isla Harbour: NM 18484 (SK. j). Caleta Lalitud: NM 18553 (SK. j). Bahia Tom: BM 80.1 1.18.563 (SN. F).BM8().1 1.18.561 (SN.d). BM 80.8.3.25 (SN. M. d). Straits of Magellan: BM 80. 11.1 8.564 ( SN. M ). BM 42.7.36 (SN. |F1), RO 35406 (SN. | F| ). Walney Sound: BM79.9.3..W(SN,M).C.rays Harbor. Smythe Channel: BM 1903,12.30.200 (SN. M). Canal Messier: BM 80. 1 i . 1 8.562 (SN, F), Bahia Churruca: BM 1903.12.30.202 (SN. F). ••Magallanes I.": YA 22796 (SN.M.j). Unnumbered downy young at .AM from IsIaTimbales. Isla Breeknoek (2), Isia Stewart, and '•BeaL'le Channel." Unsin-cifit'J — 'NM 18484(SK),NM I8553(SK), AM 1222 (SK,F). TaCHYERES LElCOCEI'inUS (61 1 Argentina Chiihin— Bahia Concepeion: SD 38277 (SN, M ). SD 38352 (SK. F). PuntaTombo: AM S5 1 3 (SK. M). Puma Tafor: RO 146919 (SK. |M|). Bahia de Huevos (Egg Harbour): AM 73.^415 (SN. M). Camarones: MA 52194 (SN, M), MA 52195 (SN. M). MA (uneataloged, Kovaes No. 75) (SN, M), MA (uneataloged, Kovaes No. 76) (SN, F), YA 82328 (SN. F). YA 823.^4 (SN. M. d): RO— 2 uneataloged. frozen birds (M. F) to be preserved as anatomieal speeimens. Puerto Melo: MA 52694/ KU 77932 (SN/SK. M. holotype). MA 52698 (SN. M. d); MA — 3 unaeeessioned skeletons given by P. S. Humphrey in 1984; KU 77925 (SK*. M). SW 3527/KU 77926 (SN/SK. F). KU 77927 (SK*. F), KU 77928 (SK*.M). KLI 77929 (SK*,F),SW 3528/ KU 77930 (SN/SK. M). KU 77931 (SK*. M). KU 77933 (SK*. M). SW 353()/KU 77934 (SN/SK, F), KU 77935 (SK*. M). SW 353 1/KU 77936 (SN/SK, F), KU 77937 (SK*. F). KU 77938 (SK*. M). KU 779,HJ (SK*. F), KU 77941 (SK*. F). SW 353.VKU 77942 (SN/SK. M). SW 3534/KU 77943 (SN/SK, M ), KU 79234 (SK*, M). KU 79235 (SK*. M). KU 792.^6 (SK*. M). KU 79237 (SK*. M). KU 79238 (SK*. F). KU 792.^9 (SK*, F). KU 79240 (SK*. F). KU 79241 (SK*. F). KU 79243 (SK*. M. j). KU 79244 (SK*. M). KU 79245 (SK. M). KU 79246 ( SK*. M). KU 79247 (SK*, F), KU 79248 (SK*. M ). KU 79249 (SK*. F), KU 79455 (SN/SK, F), KU 794.56 ( SN/SK, M), KU 79624 (A.d). KU 79625 (A. d). KU 79626 (A. d). KU 79.501 (SN. F, d), KU 79502 (SN, M, d), KU 79457 (SK*, F), MA 53329 (SN,F). MA 533.^0 (SN.M). STEAMER-DUCKS (ANATIOAE; TACHYERES) LH KRATl RK CH KD 105 Sources containing references to steumer-iiucks are indexed by subject using combinations of one or more single-letter designations; these follow the references and are enclosed in square brackets. The 12 desiiinalions and their meanings are as follows: A anatomy B behavior C captive birds D distributional data E exploitation by humans F leeding habits H habitat L locomotion M minimal mention N nesting P predation T taxononn ABBorr. C. C. 1S6I. Notes on the birds ol the Falkland Islands. Ibis .^:149-167. [A, E. N. T| Ad.\.ms.W.,.^ndR.Templetii\. I 'JTy. Ornithology. Pp.,^2- 53 m Cambridge expedition toTierra del Fuego ]'-)n. A general report and summary of seientifie results. Cambridge, England. |D. R H. N] .AfiosiiM. A. M. Dt;. 1924. Zehn Jahre im Feuerland. F. A. Brockhaus. Leipzig. [D. H. L| AoosriNi. A. 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Birds 27 — Mammals I I. .America's First Zoo 14:20-21. |C| Anon'imois. I'->73. Slimbridge: breeding results 1972. Wildfowl 24:172-174. |C| Anonymois. 1974. Breeding results. 1973, Wikhowl 25:171-173. |C| Anon>\iois. 1978. Research, conservation and educa- tion. Wildfowl 29:16.3-176. |C| Anon'imois. 1982. Wildfov\l Trust avicullural report. 1981. Wildfowl 33:174-175. [C| Anon'i MOtLS. 1983. Wildfowl Trust avicullural report, 1982. Wildfowl 34:174-175. |C| Anonymoi s. 1984. Wildlow I Trust avicullural report, 1983. Wildfowl 35:182-183. |C| Anon'imois. 1985. Wildfowl Trust avicullural report, 1984. Wildfowl 36:154-155. |C| Anon'imois. 1986. Wildfowl Trust avicullural report, 14S5. Wildfowl 37:178-179. |C| Anon'imois. 1987. Wildfowl Trusi avicullural report, 1986. Wildfowl 38:156-157, |C| Anonymolis. 1988. Wildfowl Trust avieullurai report, 1987. Wildfowl 3'-): 180-181. |C| Ak Vi \, B. l"-)82. Lisla patron de las aves chilenas, Publ. Ocas. Inst. Oceanol. Liniv. Valparaiso No. 1:1-19. 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Hornero 7:1-XIII. |T| STEAMER-DUCKS (ANATIDAE: TACHYEKES) appp:ndix 121 MlLTIVARIATK IdKNTIFK ATION OF Spfximens Bi\ AKi.ATF; Canonic \i Pi ois Skin spcciiiiviis. A reasonably precise eiassili- cation oIsUkIx skins to species can be achieved by calciilaling llie scores of each on the lirst two canonical variates shown in Fig. 25. These scores are based on three of the four basic skin measure- ments taken for most specimens in this study — nail width, tarsus length (cranial surface), and wing length (arc length of straightened wing, from wrist). Scores on each a.xis are calculated by mul- tiplying each measurement (mm) by the corre- sponding coefficient in Table Al. then summing the three resultant products with the 'constant" term foi that axis. .Alter this is done for each axis, the point can be plotted on Fig. 25 and its position indicates its likely group membership. Table Al. t'dctlicicnls (iion-siaiidardi/ed) and coii- stanls lor lirsi Ivvo canonical variates torevlcrnal mea- sureniciils (plotted in Fig. 15) separating the eight spe- eies-so\ groups of Ten liycrcs. Cocflicicnts lor Variate Term Nail width Tarsus length Wing length CoiislanI II -0. S.S.I -0..^7.^ -0.207 -0.02(1 (I.()(i7 -0.074 .s.07(l 27.2.V^ Complete skeletons. An analogous method of identihcaiion can be performed using the coeffi- cients for the 19 skeletal measurements incorpo- rated in the canonical axes depicted in Fig. 27. As described for external measurements, scores lor a specimen on each axis are calculated by summing the "constant" term with the products of each measurement (mm) with its corresponding coeffi- cient; coefficients and constants forcane)nical axes I and 1! for skeletons are given in Table A2. Because of the greater precision and dimensional- ity of the skeletal model, the resultant species-sex classifications are significantly more reliable than those based on external measurements. Table .^2. Coefficients (non-standardi/ed) and con- slanls lor lirst tv\o canonical variates for skeletal mea- surements (plotted in Fig. 27) separating eight species- sex groups of Ecu hvcies. Coeflicients for Variate Term Humerus lenath -0.294 -O.Ul Ulna lenatli 0.752 0.247 LWM -0. Ls,S 2.114 Femur head widlh -(l.l)2.s -0.03.5 Tibiotarsus length -0.117 -0.015 Tarsometatarsus lensth -0.049 0.009 LWM -0.6,U ll.()()5 Diuit-lll lenath -O.O.sO 0.030 .Sternum keel leni;lh 0.0-Sl -0.116 least width -0.2I.S -().27S posterior width -0.027 0.179 Coracoid length -0.147 0.300 basal width -0.194 0.521 Interacetabular width -0.097 0.039 Interorbital width -0.012 -0.1(14 Postorbital width -0.024 -0.030 Aiitcirbital width -0.011 -0.019 Hill height -0.1 4.S -0.124 length -0.0.^9 -0.121 Constant 22. 2M) -4.232 Cl-ASSIHC..\T10N Ft NCTIONS General nwthodoloiiy. More powerful for /'(//niv.vf discrimination among species-sex groups, but much more tedious to u.se. are classification functions. These functions are presented as coef- 122 UNIV. KANSAS MUS. NAT. HIST. M(JN(XiKAPH NO. 8 ticiciUs (U)r llic same variables iiicoiporalcd in ihc associated canonical analyses) for £'(/(■/( i;;v'///7 con- sidered in the analysis. Initially, one imist choose the two groups to compare with respect to the specimen at hand: this choice may be based on information on sex, locality, plumage pattern, or a preliminary plotting on the canonical axes de- scribed above. The specimen is then compared against the two groups simultaneously by calcu- lating the score of the specimen using as coeffi- cients the differences between corresponding co- efficients for the two groups concerned. The re- sultant score is then compared to those derived using the mean measurements for the groups being compared (Tables 3 anti 6); the group with the score most similar to that of the specimen is the group into which the specimen is tentatively clas- sified. In theory, all such pairwise comparisons can be performed, and the closest match indicates the optimal classification for the specimen. For a Tachyeres of unknown sex, this would require 28 pairwise comparisons for optimal discrimination among the eight species-sex groups. In practice, however, without the aid of a complete data set for Tachyeres specimens and appropriate computer support, most classifications will be based on dis- crimination between a smaller subset of the groups delimited by ancillary data associated with the specimens to be identified. Skin specimens. Coeflicients of classification functions are given for skin specimens of un- known sex in Table A3, and for skin specimens ol known sex in Table A4. For example, assume one wishes to classify a skin specimen ot a male steamer-duck from coastal Chubut using classifi- cation functions. Assume that the specniieii has a nail wuhli of 14 mm. tarsus lenelh ol ()3 mm. anil a wing length of 292 mm. Given that the specimen is known to be a male, the coeflicients to use are those for males only. (Table A4, in part.) Given the locality, only two species need to be considered — / leucocephaliis and T. patachonicus. Therefore the coefficients of interest are the differences be- tween those given for these two species: i.e., the coefficient for nail width is 7.4 1 S - 5.926 = 1 .492. that for tarsus length is 4.239 - 3.485 = 0.754. that for wing length is 1 .493 - 1 .76 1 = -0.268. and the constant term is -395.204 - (-408.367) = 1 3. 163. The score of the specimen is simply the sum of the products of these coefficients with the correspond- ing measurements; for this specimen the score is ( l.492)( I4)-K0.754 )(63)-f (-0.268 )(292)-i- 13.163 - 3.297. Performing similar calculations for the corresponding mean values given in Table 6. the "standard scores" are -5.494 for male T. patcichonicus and 5.2 1 5 for male /'. leucocephulus. By comparison of the signs of the scores, it is clear that the specimen is to be classified as T. Icucuceplialus. Skelehil specimens. Coefficients of classifica- tion functions for complete skeletons are presented in Table A5 for the eight species-sex groups: be- cause these functions achieve relatively high clas- sification percentages, functions based on sepa- rate sex analyses are not presented. Information on locality oi simple ratios should be used to exclude from consideration some of the species-sex classes for the skeleton at hand. In addition, the syrinx is preser\etl in many skeletal specimens of rar/ny'/cs. and the jiresence of an asymmetrically inflated bulla demonstrates unequivocally that the speci- men is a male. Partial skeletons, those lacking skidls and distal limb elements, can be classified usine coefficients i:i\cn in Tabic A6. STEAMER-DUCKS (ANATIDAE: TACHYFRES) ~ r^. >r. — r^ r I c> ri O at) — t^, C: r- — I/-, r- >c ~ r^. >C ~ ^ -T /". r-^ rr. — ' o t- >c t — -^ sC ri r^ ■«C I"*". — o f2 z t2 ^ C o U ^ fi f~. h~ c f5 ^ _ _ _ — sC --I -T r 1 — — ly, 3C IT, ri r^, ^ 'J'. Q- ■o ^w -r s^ U", 'y^i r- *r. -t r- i/~* -t rf, ~~ \C 3C r^, f"^. >/". O — O^ v. O >/". o ri ir^, 3^ r- r<, ir, ir-, i/~i 2C i^i '^. ri sC •/"- C^ ^ >c X. DC >r-. C; r- sC r- c; ■ 1 '/". o r^. r- sC r-i r- Tf ^ 1 _ u_ rl^l^l:^c^^c — oco-t- ii"- o r- o r~- r-- o^ sC -f c: '■'"i i/-i C> oc O Ov ^ ^ ri r-- oc — — '^' r-^ n-i o ir-* oc ri — nC c: DC "f O "r-, O «i-; OC a-. \C '^. o «c <^. O ri -t r- --f O r- ^ o r<-, r--r--ODC-TC:^-t-l-r-"r. O"-^, ^w~. -Tocr--wr--DC — rir-o^w-iO^— 'ri — oor^. — ' X f*-, r^i ri — -t DC r 1 — •^i ir, sT — f> — sT. 1^ r 1 -T — 1^ r*", -/■. _ -/■- oc r^, r^ — r 1 -t t rj DC ^ »r, _ '"'". "/■, r 1 — ' o ri r- O ^ w r 1 O ri r- r*"; O DC — C: = "^^ rr. — "i^. ri ri r 1 IT, — r*-, — — rj O^ ri r 1 r- r- DC 't "t >^. r- C^ ri -T -t o o ^ 1^ — -r ^ O oc IT", r I r 1 1/-, X r^. O -t X O — ''i-rir'-, — -"to^riri-T — ur, ri -r C> 1-^, — ri ri IT-, r- — G^ -r -t c. c^_ i^. ri r- d ■^' sC r-ori(A-, o^nor^ri r] 00 rr, c: ri rr, ir. o v* w~, — O r I «r-. O ir, — -T d d (-^l d -+ — — —' ^ O^ \C rr-, [^ .Q^ -f -f- yZ rr-, ir. -T ri r-- — r- o^ r^. — — ■ O ^ li^; — O O X cr d — r-^ d ri oc — ri o — ^ -t — r- nC q ^ o ^c — d u-^i «i-] r~- ri 1^ -t — C- nC X C' ri ^ r«-, X X o ^c — _: -tw^. O^-rrisC'-^. — X O '^ ^ '■''- — >r-, O 3^ ir^, w-i r-^ ir, V; 1^1 X ^c -f "f d ri o^' d — ^d d tr] \C c 3: o o > - — T a li H P Q Cr: "2 -c " — ^ S t i'l I '^ I ■; ■2 — is -£ "S -= — - U £ £ S. < E u STEAMER-DUCKS (ANATIDAE: TACHYF.RES) 125 -t X r^ — c^■ '^. — r-- I/", ^ ri sc r- w r~- ri ri ri 3C — f-^, r- ri r^. r-- oc o^ r-- ri r^, ri o^ O O " IT- O ri ri O — ir, r I r- 1^. >:: r- — > On ^ — '•'*. ir. r^. r~~- o- r\ 'O^' r^ 0-- — o — r*-, — -t — rin — ^- r I -1- -r ^C r^, r I ly^, — C^ >c C:* ri — jC yz X. a^ r^-, r- >c O" O ^ DC a^ ri ■c^ o Gc cc c^ — r^, ri r*-. -jc ::;• r~~~ r~~ -t — 'n — r- — DC — DC ri o — r I r \ ir. Vi -t — r 1 r- 5 DC r 1 DC r I n-, r^ — iTi ri i~*"j — •^ — r I h- ■C -t O- r \ r \ r~- yi -t o- Dc^Dc-r — r--r DCsC — r-DCCXC r i r-- r^. ir, r i r^, — \r. T. r- -r 1-^. r- r--, — 3^ r~~ r i :Z — — r*'. — ir, -y- '/"- — "T, ir, ~ G^ -r — x; ir, ir, r^, r-- r- r- '/", r t r^, O r 1 — ^_ — ■—. ~ I — ir, ir, — r^. — li^, o < H f- 5 n: u. C -J IT) o .±; ~ - ■ P - o — r-- o IllillllilUnlll.lll .11 Jl 3 2044 072 228 786 PREVIOUS M()N()(;RAPHS 1 . The H\ lid Frogs of Middle America. By William F. Diiellman. Pp. 1-753. 324 text-figures. 4 1 black- and-u hiie plates. 3 1 color plates (bound in two volumes). December 15. 1970. Cloth bound. Out-of- piint. 2. Rcatliiigs m Mamnialogy. By J. Knox Jones and Sydney Anderson (editors). Pp. 1-586. 1970, Paper boiinil. Oiit-of-pruit. 3. Disiiibution ot Mammals in Colorado. By David M. Amistrcmg. Pp. 1 — H5, 333 text-ligures, IS plates. July 20. 1972. Cloth bound. Out-of-priiit. 4. luiward IJ.Tay lor: Recollections of, \ii llerpetologisi. By Fdward H,Taylor.A, Byron Leonard, llobart M, Smith, and George R, Pisaiii. Pp, 1 -160. 6 text-figures. 1 plate. December 15. 1975. Paper bound. 5. Selected Readings in Mammahtgy. By J, Knox Jones. Sydney Anderson, and Robert S. Hoffmann (editors). Pp. 1-640. November 1976. Paper bound. ISBN 0-8933S-O01-6. 6. North .American Quaternary Coiiis. By Ronald M, Nowak, Pp, 1-154. 55 text-figures. 1 color plate, September 1. 1979, Paper bound, ISBN 0-S933S-007-5. 7. The South American llerpctolaiina: Its Origin. l:\i)lution, and Dispersal, By William I:, Duellman (editor). Pp. 1^5S. 172 text-figures, December 2S, 1979, Paper bound, ISBN 0-S933S-0()S-3,