992 ShortCommunications [Auk,Vol. 100

at the mouth of the Rio Magdalenanear Barranquilla, siblethat armentimay occurnearer to Panamain suit- discovereda population of armentithere, and in both able spotsin the still little-worked sectionsof north- yearshe collecteda good number of specimens,thus ern C6rdobaand Antioquia provinces.The isolation corroboratingthe correctnessof the type locality and of armentiprobably resulted from the intervening casting doubt on Leticia as a locality of record. Dr. presence of a considerable area of humid forest in Toro-Garciafirst observedthe specieson 16 June1969, Panama and in northwestern Colombia. M. aeneus is in company with Shiny Cowbirds (Molothrusbonar- but one of a number of speciesof semi-arid,or at iensis)but saw no more until early November of that least fairly open, parts of Middle America that has year, when he noted flocksof them daily until early its nearestally on the Caribbeanslope of Colombia. December. On 25 March 1970 he collected a young Now, with increasingnumbers of man-madeclear- male but saw no others until 20 October, when flocks ings, M. aeneushas been extendingits range south- of 100-200 individuals were noted and additional ward in Panama on both slopes. specimens were taken. From then to 11 December With 12 specimensnow availablefor study in the flocks of 20-30 birds were seen almost daily. museumsof New York and Bogota,it becomesclear Dr. Toro-Garciareported seeing armenti chiefly on that armenticannot be looked upon as other than a the ground (in which respectit agreeswith aeneus), southernmostrace of the speciesM. aeneus.M. ar- perchingon small trees(Prosopis julifiora), or flying mentiagrees with aeneusin the emarginationof the 30-50 m from tree to tree as he approachedthem. So primaries in the adults. Inasmuch as no adult females far he has not been able to furnish any information of armentihave been describeduntil now, it may be abouttheir breeding habits.If armenti,like the closely put on record that in colorationthey resemble,but allied aeneus,is a brood parasite,which seemsalmost are not quite as glossyas, female M. aeneusassimilis. certain, it probably dispersesand no longer gathers The adult males of armenti resemble those of aeneus in conspicuousflocks during the main nestingseason but are lessbronzy, more brownish. The brown color of its presumedhost species,when it would be more of the head and body of armenti,while more irides- likely to be overlooked.In 1913,when the late M. A. cent, is not unlike that of the head of male ater (Parkes Carriker, Jr. visited the narrow sandy eastern end of and Blake 1965). The bill of adult armentiis somewhat Salamanca Island, he never saw armenti. Dr. Toro- shorter and slenderer than that of aeneus. Garciaeven venturedto surmisethat while breeding it may be absent from the island, as it is a bird of LITERATURE CITED partly open habitats,favoring lesshumid regionsor areasthat, becauseof clearingby man for agriculture, FRIEDMANN, H. 1933. Notes on Arment's Cowbird, have becomesemi-arid. In the stomachsof the spec- Tangaviusarmenti (Cabanis). Ibis 75: 492-494. imens he collectedhe found small, unidentified grass 1957. The rediscoveryof Tangaviusarmenti seedsand also many rice seeds.(There are somesmall (Cabanis). Auk 74: 497-498. rice plantations to the south of Salamanca Island, PARKES,K. C., & E. R. BLAKE.1965. Taxonomy and across the Carlo Clarin.) nomenclature of the Bronzed Cowbird. Field- The southernmost Panamanian locality where iana-Zoology 44: 207-216. aeneushas been found, Rio Chepo,on the Pacificslope of eastern Panama, is about 400 km (220 miles) from Received3 January1983, accepted 18 April 1983. Cartagena,where armentioccurs. It seemsquite pos-

Lek Behavior of the Lesser Bird of Paradise

BRUCE BEEHLER • Departmentof Biology,Princeton University, Princeton, New Jersey08544 USA

The birds of paradise(Paradisaeidae) are promi- cited as textbookexamples of the promiscuouslife- nent among an array of vertebrate groups that have style,and the exaggerateddisplay plumes of the males becomethe focalpoint for biologistsstudying sexual of some paradisaeidspecies are consideredto be il- selectionand lek behavior (Emlen and Oring 1977, lustrativeof the extremeproducts of runawayselec- Foster 1977, Wittenberger 1979, Wrangham 1980, tion, which occurswhen only a small proportion of LeCroy et al. 1980,Bradbury 1981,LeCroy 1981,Dia- malesreproduce successfully in any breedingseason. mond 1981, Oring 1982). Birds of paradise are often This view is surprising,as there has been no defini- tive field study of these birds in their native habitat that documentseither polygynousmating or skewed Present address:National Museum of Natural History, MRC 114, mating successfor males of any speciesof bird of Smithsonian Institution, Washington, D.C. 20560 USA. paradise(Gilliard 1969, Dinsmore 1970, Cooperand October 1983] ShortCommunications 993

Forshaw 1977, LeCroy 1981). In this paper I present TABLE1. Lek attendanceand mating successin Less- the first conclusivefield observationsof a strongly er Birds of Paradise. skewedmating successamong a lek-displayinggroup of male birds of paradise. In addition, I comment on Timed the importanceof female choicevs. male-male com- attendance petition in the mating habits of this species. Bird' (min) b Copulations The Lesser Bird of Paradise (Paradisaeaminor) in- 1 960 25 habits rainforest of the lowlands and hills of north- 2 720 1 western New Guinea (Gilliard 1969, Cooper and For- 3 390 0 shaw 1977). Morphologically and behaviorally, it is 4 390 0 5 360 0 very similar to other membersof the Paradisaeaapoda 6 195 0 superspecies,all of which are notable for the re- 7 585 0 c markable nuptial plumage of the males,extreme sex- 8 105 0 ual dimorphism,and lek courtshipdisplay (LeCroy ' This linear sequenceis not equivalent to any perceived "mating 1981). ! observed a lek of Lesser Birds of Paradise at hierarchy." The numbers simply refer to the perch number that the the National Bird of ParadiseSanctuary, Baiyer Riv- bird attended. bTotal recorded attendancetimes for these birds during a period of er, Western Highlands Province,Papua New Guinea timed observationsduring Juneand July 1979. (5ø31'S,144ø71'E, 1,200 m elevation) on 18 days from c Female solicited from this male for more than 3 min, but the male 2 June to 4 July 1979, for a total of 49 h. During part never mounted. of this period, I timed attendanceby the birds, and at other times I monitored behavioral interactions. This lek has been used for at least 12 yr by an un- becausethe outer perches were occupied less faith- disturbed population of LesserBirds of Paradise(R. fully. During my study, ! documentedno exchange D. Mackaypers. comm.). Aided by a 15X telescope,I of perches, temporary or otherwise. I assignednum- observedthe birds from the ground, 45 m from the bers to perches;the males that held particular perch- lek. Althoughindividuals at the lek were not marked, es were given the same number as the perch they after a few daysof preliminary observationI wasable frequented. to identify the four males that occupiedthe central In addition to the regular attendant males, an ad- perches of the lek individually by physical differ- ditional numberof males,most in subadultplumage, encesin pectoralplumes, tail wires, and head mark- visited the lek but did not own perches.These birds ings. I monitored attendanceat the lek, visits by fe- spent most of the time out of the lek, calling from males,copulations, and activitiesamong males. My perches dispersedthrough the surrounding forest. observationsof the physical organization of the lek They would visit the lek when courtshipactivities of this speciesare in accord with those of Gilliard reacheda peak. These birds observedthe courtship (1969: 235), although elsewhere (Gilliard MS, as not- activitiesbut never actually displayed,nor did I ob- ed in LeCroy 1981: 10) Gilliard reported instancesof serve them to copulate with females at the lek. significantlocal variation in lek size and male orga- When a female entered the lek to mate, the perch- nization in this species.Here, I confine discussionto holding malesbecame visibly agitated,called loudly, activities in a single lek. erected their yellow pectoral plumes, and often The Baiyerlek was confinedto a singletree (32 m hoppedabout from limb to limb, flapping their wings tall) at the edgeof a clearing.Males held individually and shivering their plumes (see LeCroy 1981). After owned perchesclustered in a portion of the tree this brief flurry of motion and calling, the males as- where severallarge branchesheld up a tangle of epi- sumed their perches and quietly displayed their phytic vines. Individual malesoccupied perches on erected pectoral plumes while the female moved the horizontalor gently slopingparts of the branch- about the lek, often visiting the limbs of severaldif- es. The same percheswere occupiedday after day. ferent males in display. I never saw a male attempt Interperch distancewas as small as 50 cm. ! had un- to mount a female without a seriesof precopulatory obstructed views of the males because of the birds' behaviors that included explicit solicitation by the habit of plucking all green vegetationfrom the im- female (for details see LeCroy 1981).! observedmat- mediatevicinity of their perches.From the following ing to occur only with males at their particular observationsI determined that the male birds of par- perches. adise "owned" the perches that they attended and Males were present at the lek from 0600 to 0900 maintained. In the lek I was able to identify eight and 1430 to 1715. I recorded females visiting from perchesthat were usedby maleson a daily basis.The 0630 to 0730 and 1445 to 1715; most copulations, four central percheswere owned by positively iden- however, occurred from 0645 to 0715 and 1500 to tified males. The outer four perches were attended 1530.During the 18 days of observations,! recorded by males whose individual identity was less certain 99 visits by females and 26 copulations,which in- to me, in part becausein this short study I had to volved only two males. focus on the central (most active) birds, and in part Male 1 performed 25 of 26 copulationsthat I re- 994 ShortCommunications [Auk, Vol. 100

corded. Male 2 copulated once. A female solicited cessappears to be clear from three observations.First, copulation from Male 7, but he failed to mount. No the stereotypedprecopulatory interactions between other male copulated.Male 1 invested more time in male and female first involve the female moving, un- lek attendancethan any other (Table 1). It is inter- harassed,through the lek, as though "sampling"the esting to note that only the three most faithful male displaying males, who remain stationed at their attendants at the lek received solicitations from fe- perches. Second, to initiate a copulation, the female males. Levels of attendance varied widely, from 105 approachesand solicitsfrom a displayingmale, while rain by Male 8 to 960 rain by Male 1. he remains passivelyat his perch. Third, I observed My observationsat this lek of the LesserBird of a female choose and mate with Male 2 while Male 1 Paradise provide the first direct evidence that, for was present, only 50 cm away; that Male 1 did not this species,some males mate polygynouslyand that interfere shows that the most successful male in the (at leastin the shortterm) matingsuccess among males lek doesnot forciblycontrol lek mating in this species. is strongly skewed, in accordancewith predictions Whether the female is choosingthe "best" male or for speciesthat exhibit strongsexual dimorphism and the central perch is unclear from my limited obser- arena courtshipdisplay (Gilliard 1969,Wittenberger vations. Nonetheless, the fact that females chose to 1979, Oring 1982). mate with Males 1, 2, and 7 (or perches 1, 2, and 7) Data on male-femaleinteractions at the lek provide indicates that there is no simple male-controlled some insight into the nature of sexualselection in mechanism operating (as in a situation in which all this type of breeding system.Bradbury (1981) pos- femaleswould mate with the bird occupyingperch tulated that female choiceof matesis a driving force 1) and, further, that females are an important com- in the evolution of the lek system.In contrast,Le- ponent of the mate-choiceprocess. To gain a full un- Croy (1981) assertedthat male-male hierarchical in- derstandingof mating interactionin paradisaeidleks, teractionsare of primary importancein lek mating, it will be necessaryto study color-markedbirds over at least for birds of paradise.She argued that: (1) the periods exceedinga single breeding season. elaboratedisplays and plumagesof the speciesof Fieldwork in Papua New Guinea was made possi- Paradisaeawere •sed primarily in male-male domi- ble by grants from the Smithsonian Institution, nance interactions, (2) there was no evidence that Princeton University, and Sigma Xi. I thank R. D. sexuallyreceptive females "sample" numerous males, Mackay,Superintendent of the BaiyerRiver Sanctu- and (3) "the female remain[s] passive in terms of ary, for assistanceand the Wildlife Division, Papua choosinga mate" (LeCroy 1981:48). New Guinea, for permission to carry out the re- A number of anecdotal observations that ! made at search. M. S. Foster,H. S. Horn, M. K. LeCroy, J. W. the lek of Paradisaea minor indicate that both female Terborgh, R. F. Pasquier,S. Olson, S. Zack, R. Zusi, choice and male-male hierarchical control may be and an anonymousreviewer made helpful comments important in the organization of mating in this on earlier drafts of this paper. species. Two observations could be interpreted as evidence for male-male control of mating. First, the LITERATURE CITED perchof Male 1 was the site where mostcopulations occurred.Twice I observedMale 1 depart this perch BRADBURY,J. W. 1981. The evolution of leks. Pp. to feed at a nearby fruit tree for several minutes. 138-169 in Natural selection and social behavior During his absenceno rival male took over the perch. (R. D. Alexanderand D. Tinkle, Eds.).New York, Also, on the one morning when Male 1 was not the Chiron. first to arrive at the lek, Male 2 arrived first, and COOPER,W. T., & J. FORSHAW. 1977. The birds of assumedhis perch (2) not the perch of Male 1, which paradiseand bowerbirds.Sydney, Australia, Col- remained empty. It could thus be argued that in this lins. hierarchicalsystem, perch ownership is rigid and that DIAMOND,J. M. 1981. Birdsof paradiseand the the- male-maleinteractions reinforce this rigid hierarchy. Dry of sexualselection. Nature 293: 257-258. To test this, one would have to observe the lek in the DINSMORE,J. J. 1970. Courtship behavior of the early part of the breeding season.At that time one Greater Bird of Paradise. Auk 87: 305-321. might expectmuch male-malefighting; after sucha EMLEN,S. T., & L. W. ORING. 1977. Ecology,sexual period the lek might stabilize and later in the season selection,and the evolution of mating systems. appear to be a peaceful and cooperativesystem. Sec- Science 197: 215-223. ond, Male 7 failed to copulatewhen solicitedby a FOSTER,M.S. 1977. Odd couplesin manakins:a study female. This can be interpreted as an instance in of socialorganization and cooperativebreeding which the behavioral subordination of the lek hier- in Chiroxiphialinearis. Amer. Nat. 111: 845-853. archy inhibits copulationby a low-ranking bird when GILLIARD,E.T. 1969. The birds of paradiseand bow- higher-ranking birds are present.Clearly, more data er birds. Garden City, New York, Natural His- are needed to test these interpretationssufficiently. tory Press. That femalesare involved in the mate choicepro- LECROY,M. 1981. The genusParadisaea: display and October 1983] ShortCommunications 995

evolution. Amer. Mus. Nat. Hist. Novitates 2714: WITTENBERGER,J. 1979. The evolution of mating sys- 1-52. tems in birds and mammals. Pp. 271-349 in -, A. KuLuPI, & W. S. PECKOVER. 1980. Goldie's Handbook of behavioralneurobiology, vol. 3 (P. Bird of Paradise:display, natural history, and Marler and J. G. Vandenbergh,Eds.). New York, traditional relationshipsof the people to the bird. Plenum Press. Wilson Bull. 92: 289-301. WRANGHAM, R.W. 1980. Female choice of least cost- OraNG,L. W. 1982. Avian mating systems.Pp. 1-92 ly males:a possiblefactor in the evolution of in Avian biology, vol. 6 (D. S. Farner and J. R. leks. Z. Tierpsychol.54: 357-367. King, Eds.).New York, AcademicPress.

A Dusky Warbler (Phylloscopusœuscatus) on SoutheastFarallon Island, California

PETERB. PYLE,DAVIO F. DESANTE,ROBERT J. BOEKELHEIOE,ANO ROBERT P. HENOER$ON PointReyes Bird Observatory,4990 ShorelineHighway, Stinson Beach, California 94970 USA

Southeast FarMIon Island, located 42 km west of uniformly coloredupperparts were noted before the San Francisco,California, has long been recognized bird flew up the steephill leading to the lighthouse for its capacityto attractvagrant birds (DeSanteand and disappearedover a ridge. Ainley 1980).The appearancethere of a Dusky War- At 1030 Boekelheide relocated the bird and cap- bier (Phylloscopusfuscatus) on 27 September1980, tured it in the island'sHeligoland trap. With the bird however, exceededour most imaginative expecta- in hand, the six persons present on the island (in- tions. It is only the fourth record for the speciesin cluding Henderson,Lee Astheimer, and Peg Abbott) North America and, more important, the first for any were ableto arriveat the correctidentification: Dusky member of this widespreadEurasian genus south of Warbler. The bird weighed 7.7 g at capture, had no Alaska. fat, and was measured and photographed (Fig. 1). After severaldays of clear skiesand strong north Additional photosare on file with the California Bird to northwest winds, the morning of 27 September Records Committee of the Western Field Ornitholo- brought diminished winds and overcast skies to gistsand at the Point ReyesBird Observatory. SoutheastFarallon. Accompanyingthis change in An attempt was made to keep the bird alive for weather was one of the seasoh'sbetter migrant pas- transportoff the island on the next day's scheduled sefine groundings.This wave was characterizedby boat, but it died during the afternoon.The specimen relatively large numbersof Hermit Thrushes(Catha- was deposited in the collections of the California rus guttatus),Ruby-crowned Kinglets (Reguluscalen- Academyof Sciences(CAS 70314)and wasconfirmed dula), and Golden-crownedSparrows ( Zonotrichiaatri- to be an immature female of the nominate race by capilia),lesser numbers of Varied Thrushes (Ixoreus John Bull (pers. comm.) and Ben King (pers. comm.) naevius),Townsend's Warblers (Dendroicatownsendi), at the American Museum of Natural History. The bird and Puget Sound White-crowned Sparrows (Zono- had no molt, a partially pneumaticizedskull, and mi- trichia leucophryspugetensis), and one Rusty Song nute ovaries.The upper mandiblewas entirely dark Sparrow (Melospizamelodia morphna). This speciesas- and the lower was dark with a yellow base.The legs semblagestrongly implied a northwesterncoastal or- were dark brownish-graywith yellow soles.The eye igin for the wave, although at least 10 individuals of was dark olive-brown. Some measurements were: ex- various "eastern" wood warblers also appeared that posedculmen, 7.5 ram; culmen from nostril, 6.7 ram; day. tarsus, 27 ram; flattened wing, 62 mm; and tail, 49 Around 0945, Pyle joined Brian Pendleton, who was puzzling over a strangecall note emerging from The Dusky Warbler breedsin central USSR from some low scrub near the east end of the island. The the Ob River east to the Anadyr Basin(Williamson note, transcribedas "tchk" or "chak," was striking 1962) and winters in the Himalayas and southeast for its loudnessand dryness;it seemedespecially odd Asia. Ticehurst (1938) recognized two races,the nom- after the bird was flushed and found to be a small inate, which is found over mostof the species'range, wood warbler-like passerine.The bird was chasedfor and a darker, more resident Himalayan form, P. f. about 3 rain, but a view adequatefor identification weigoldi.The specieshas a fairly good potential for was not obtained because of the bird's furtive habit vagrancyas evidenced by at least35 documentedwest of seekingout low thick cover.Only "nervous"wing European records between 1958 and 1980 (Svensson and tail flicking, a buff-white supercilium, and dull pets. comm.).There have alsobeen three occurrences