992
Short
Communications
at the mouth of the Rio Magdalenanear Barranquilla,
discovereda population of armentithere, and in both
yearshe collecteda good number of specimens,thus
corroboratingthe correctnessof the type locality and
castingdoubt on Leticia as a locality of record. Dr.
Toro-Garciafirstobservedthe specieson 16 June1969,
in companywith Shiny Cowbirds (Molothrusbonariensis)but saw no more until early November of that
year, when he noted flocksof them daily until early
December.On 25 March 1970 he collecteda young
[Auk,Vol. 100
siblethat armentimayoccurnearerto Panamain suitable spotsin the still little-worked sectionsof northern C6rdobaand Antioquia provinces.The isolation
of armentiprobablyresultedfrom the intervening
presence of a considerable area of humid forest in
Panama and in northwestern
Colombia.
M. aeneus is
but one of a number of speciesof semi-arid,or at
least fairly open, parts of Middle America that has
its nearestally on the Caribbeanslope of Colombia.
Now, with increasingnumbersof man-madeclearmale but saw no others until 20 October, when flocks
ings, M. aeneus
has been extendingits range southof 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-Garciareportedseeingarmentichiefly on that armenticannot be looked upon as other than a
the ground (in which respectit agreeswith aeneus), southernmostrace of the speciesM. aeneus.M. arperchingon small trees(Prosopis
julifiora),or flying mentiagreeswith 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 breedinghabits.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 conspicuous
flocksduring 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 irideslikely to be overlooked.In 1913,when the late M. A.
cent, is not unlike that of the head of male ater (Parkes
and Blake 1965). The bill of adult armentiis somewhat
Carriker, Jr. visited the narrow sandy eastern end of
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
partly open habitats,favoring lesshumid regionsor
areasthat, becauseof clearingby man for agriculture,
have becomesemi-arid.In the stomachsof the specimenshe collectedhe found small,unidentified grass
seedsand alsomany rice seeds.(There are somesmall
rice plantations to the south of Salamanca Island,
LITERATURE CITED
FRIEDMANN,H.
1933. Notes on Arment's Cowbird,
Tangavius
armenti(Cabanis).Ibis 75: 492-494.
1957. The rediscoveryof Tangavius
armenti
(Cabanis). Auk 74: 497-498.
PARKES,
K. C., & E. R. BLAKE.1965. Taxonomy and
across the Carlo Clarin.)
nomenclature
The southernmost Panamanian locality where
aeneus
hasbeenfound, Rio Chepo,on the Pacificslope
iana-Zoology 44: 207-216.
of eastern Panama, is about 400 km (220 miles) from
of the Bronzed
Cowbird.
Field-
Received
3 January1983,accepted
18 April 1983.
Cartagena,where armentioccurs.It seemsquite pos-
Lek Behavior
of the Lesser Bird of Paradise
BRUCE BEEHLER •
Departmentof Biology,PrincetonUniversity,Princeton,
New Jersey08544 USA
The birds of paradise(Paradisaeidae)are prominent among an array of vertebrategroupsthat have
becomethe focalpoint for biologistsstudyingsexual
selectionand lek behavior (Emlen and Oring 1977,
Foster 1977, Wittenberger 1979, Wrangham 1980,
LeCroy et al. 1980,Bradbury 1981,LeCroy 1981,Dia-
cited as textbookexamplesof the promiscuouslifestyle,and the exaggerateddisplayplumesof the males
of some paradisaeidspeciesare consideredto be il-
mond 1981, Oring 1982). Birds of paradise are often
lustrativeof the extremeproductsof runawayselection, which occurswhen only a small proportionof
malesreproducesuccessfully
in any breedingseason.
This view is surprising,as there hasbeen no defini-
Present address:National Museum of Natural History, MRC 114,
Smithsonian Institution, Washington, D.C. 20560 USA.
tive field study of thesebirds in their native habitat
that documentseither polygynousmatingor skewed
mating successfor males of any speciesof bird of
paradise(Gilliard 1969,Dinsmore1970,Cooperand
October 1983]
ShortCommunications
Forshaw 1977, LeCroy 1981). In this paper I present
the first conclusivefield observationsof a strongly
skewedmating success
amonga lek-displayinggroup
of male birds of paradise. In addition, I comment on
the importanceof female choicevs. male-male competition in the mating habits of this species.
The Lesser Bird of Paradise (Paradisaeaminor) inhabits rainforest
of the lowlands
and hills of north-
western New Guinea (Gilliard 1969, Cooper and Forshaw 1977). Morphologically and behaviorally, it is
very similar to other membersof the Paradisaea
apoda
superspecies,all of which are notable for the remarkablenuptial plumage of the males,extremesex-
ual dimorphism,and lek courtshipdisplay (LeCroy
1981). ! observed a lek of Lesser Birds of Paradise at
the National Bird of ParadiseSanctuary,Baiyer River, WesternHighlands Province,PapuaNew Guinea
(5ø31'S,144ø71'E,1,200m elevation) on 18 daysfrom
2 June to 4 July 1979, for a total of 49 h. During part
of this period, I timed attendanceby the birds, and
at other
times I monitored
behavioral
993
TABLE1. Lek attendanceand mating successin Lesser Birds of Paradise.
Timed
attendance
Bird'
(min) b
1
960
2
3
4
5
6
7
8
720
390
390
360
195
585
105
Copulations
25
1
0
0
0
0
0c
0
' This linear sequenceis not equivalent to any perceived "mating
hierarchy." The numberssimply refer to the perch number that the
bird attended.
bTotal recorded attendancetimes for thesebirds during a period of
timed observationsduring Juneand July 1979.
c Female solicited from this male for more than 3 min, but the male
never mounted.
interactions.
This lek has been used for at least 12 yr by an undisturbed population of LesserBirds of Paradise(R.
D. Mackaypers.comm.).Aided by a 15X telescope,I
observedthe birds from the ground, 45 m from the
lek. Althoughindividualsat the lek were not marked,
after a few daysof preliminary observationI wasable
to identify the four malesthat occupiedthe central
perches of the lek individually by physical differencesin pectoralplumes,tail wires, and head markings. I monitored attendanceat the lek, visits by females,copulations,and activitiesamong males.My
observationsof the physical organization of the lek
of this speciesare in accord with those of Gilliard
becausethe outer perches were occupied less faithfully. During my study, ! documentedno exchange
of perches,temporary or otherwise. I assignednumbers to perches;the males that held particular perches were given the same number as the perch they
frequented.
In addition to the regular attendant males,an ad-
ditional numberof males,mostin subadultplumage,
visited the lek but did not own perches.These birds
spent most of the time out of the lek, calling from
perches dispersedthrough the surrounding forest.
They would visit the lek when courtshipactivities
reacheda peak. These birds observedthe courtship
activitiesbut never actually displayed,nor did I ob-
(1969: 235), although elsewhere (Gilliard MS, as noted in LeCroy 1981:10) Gilliard reported instancesof serve them to copulate with females at the lek.
significantlocal variation in lek size and male orgaWhen a female entered the lek to mate, the perchnization in this species.Here, I confine discussionto holding malesbecamevisibly agitated,called loudly,
activitiesin a single lek.
erected their yellow pectoral plumes, and often
The Baiyerlek was confinedto a singletree (32 m hoppedaboutfrom limb to limb, flappingtheir wings
tall) at the edgeof a clearing.Malesheld individually and shivering their plumes (see LeCroy 1981). After
owned perchesclusteredin a portion of the tree this brief flurry of motion and calling, the malesaswhere severallarge branchesheld up a tangle of epi- sumed their perches and quietly displayed their
phytic vines. Individual malesoccupiedpercheson erected pectoral plumes while the female moved
the horizontalor gently slopingpartsof the branch- about the lek, often visiting the limbs of severaldifes. 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 seeLeCroy 1981).! observedmatmediatevicinity 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 perchesthat 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 daysof observations,! recorded
by maleswhose individual identity was lesscertain 99 visits by females and 26 copulations,which into 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
copulation from Male 7, but he failed to mount. No
other male copulated.Male 1 invested more time in
lek attendancethan any other (Table 1). It is interesting to note that only the three most faithful male
cessappearsto be clear from three observations.First,
the stereotypedprecopulatoryinteractionsbetween
male and female first involve the female moving, un-
attendants
perches.Second, to initiate a copulation, the female
at the lek received
solicitations
from
fe-
harassed,through the lek, as though "sampling"the
displaying males, who remain stationed at their
males. Levels of attendance varied widely, from 105
rain by Male 8 to 960 rain by Male 1.
My observationsat this lek of the LesserBird of
Paradiseprovide the first direct evidence that, for
approaches
and solicitsfrom a displayingmale,while
he remains passivelyat his perch. Third, I observed
this species,somemalesmatepolygynouslyand that
(at leastin the shortterm)matingsuccess
amongmales
is strongly skewed, in accordancewith predictions
for speciesthat exhibitstrongsexualdimorphismand
arenacourtshipdisplay(Gilliard 1969,Wittenberger
1979,Oring 1982).
Data on male-femaleinteractionsat the lek provide
some insight into the nature of sexualselectionin
this type of breeding system.Bradbury(1981) postulated that femalechoiceof matesis a driving force
in the evolution of the lek system.In contrast,LeCroy (1981) assertedthat male-male hierarchical interactionsare of primary importancein lek mating,
at leastfor birds of paradise.She argued that: (1) the
elaboratedisplaysand plumagesof the speciesof
Paradisaea
were •sed primarily in male-male domi-
interfere
nance interactions, (2) there was no evidence that
sexuallyreceptivefemales"sample"numerousmales,
and (3) "the female remain[s] passive in terms of
choosinga mate" (LeCroy 1981:48).
A number
of anecdotal
observations
that ! made at
the lek of Paradisaea minor indicate that both female
choice and male-malehierarchicalcontrol may be
important in the organization of mating in this
a female
choose and mate with
Male
2 while
Male
1
was present, only 50 cm away; that Male 1 did not
shows that the most successful male in the
lek doesnot forciblycontrollek matingin this species.
Whether the female is choosingthe "best" male or
the central perch is unclear from my limited observations. Nonetheless,
the fact that females chose to
mate with Males 1, 2, and 7 (or perches1, 2, and 7)
indicates that there is no simple male-controlled
mechanism operating (as in a situation in which all
femaleswould mate with the bird occupyingperch
1) and, further, that females are an important component of the mate-choiceprocess.To gain a full understandingof mating interactionin paradisaeidleks,
it will be necessaryto study color-markedbirds over
periods exceedinga single breeding season.
Fieldwork in Papua New Guinea was made possible by grants from the Smithsonian Institution,
Princeton University, and Sigma Xi. I thank R. D.
Mackay,Superintendentof the BaiyerRiver Sanctuary, for assistanceand the Wildlife Division, Papua
New Guinea, for permission to carry out the research.M. S. Foster,H. S. Horn, M. K. LeCroy, J. W.
Terborgh, R. F. Pasquier,S. Olson, S. Zack, R. Zusi,
and an anonymousreviewer madehelpful comments
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 wasthe site where mostcopulations
J. W. 1981. The evolution of leks. Pp.
occurred.Twice I observedMale 1 depart this perch BRADBURY,
138-169 in Natural selection and social behavior
to feed at a nearby fruit tree for several minutes.
During his absenceno rival male took over the perch.
(R. D. Alexanderand D. Tinkle, Eds.).New York,
Chiron.
Also, on the one morning when Male 1 wasnot the
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
remained empty. It could thus be argued that in this
paradiseand bowerbirds.Sydney,Australia,Col-
hierarchicalsystem,perchownershipis rigid and that
male-maleinteractionsreinforcethis rigid hierarchy.
DIAMOND,J. M. 1981. Birdsof paradiseand the theDry of sexualselection.Nature 293: 257-258.
DINSMORE,J. J. 1970. Courtship behavior of the
To test this, one would have to observe the lek in the
lins.
Greater Bird of Paradise. Auk 87: 305-321.
early part of the breeding season.At that time one
might expectmuch male-malefighting; after sucha EMLEN,S. T., & L. W. ORING. 1977. Ecology,sexual
period the lek might stabilizeand later in the season
selection,and the evolution of mating systems.
appear to be a peaceful and cooperativesystem.Sec-
ond, Male 7 failed to copulatewhen solicitedby a
female. This can be interpreted as an instance in
which
the behavioral
subordination
of the lek hier-
archyinhibits copulationby a low-rankingbird when
higher-ranking birds are present.Clearly, more data
are needed to test these interpretationssufficiently.
That femalesare involved in the mate choicepro-
Science
197: 215-223.
FOSTER,
M.S. 1977. Odd couplesin manakins:a study
of socialorganizationand cooperativebreeding
in Chiroxiphialinearis.Amer. Nat. 111: 845-853.
GILLIARD,E.T. 1969. The birds of paradiseand bower birds. Garden City, New York, Natural History Press.
LECROY,
M. 1981. The genusParadisaea:
displayand
October 1983]
evolution.
ShortCommunications
Amer.
Mus. Nat. Hist. Novitates
2714:
1-52.
-, A. KuLuPI, & W. S. PECKOVER. 1980. Goldie's
Bird of Paradise:display, natural history, and
traditional relationshipsof the people to the bird.
Wilson
Bull. 92: 289-301.
995
WITTENBERGER,
J. 1979. The evolution of mating systems in birds and mammals. Pp. 271-349 in
Handbook of behavioralneurobiology,vol. 3 (P.
Marler and J. G. Vandenbergh,Eds.).New York,
Plenum
Press.
WRANGHAM, R.W.
OraNG,L. W. 1982. Avian mating systems.Pp. 1-92
in Avian biology, vol. 6 (D. S. Farner and J. R.
King, Eds.).New York, AcademicPress.
1980. Female choice of least cost-
ly males:a possiblefactor in the evolution of
leks.Z. Tierpsychol.54: 357-367.
A Dusky Warbler (Phylloscopusœuscatus)
on SoutheastFarallon Island, California
PETERB. PYLE,DAVIO F. DESANTE,ROBERTJ. BOEKELHEIOE,
ANO
ROBERT P. HENOER$ON
PointReyesBirdObservatory,
4990 Shoreline
Highway,StinsonBeach,California94970USA
Southeast FarMIon Island, located 42 km west of
uniformly coloredupperpartswere notedbeforethe
San Francisco,California, has long been recognized bird flew up the steephill leading to the lighthouse
for its capacityto attractvagrantbirds(DeSanteand and disappearedover a ridge.
At 1030 Boekelheiderelocated the bird and capAinley 1980).The appearancethere of a Dusky Warbier (Phylloscopus
fuscatus)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 (intions. It is only the fourth record for the speciesin
cluding Henderson,Lee Astheimer, and Peg Abbott)
North Americaand, more important, the first for any wereableto arriveat the correctidentification:
Dusky
member of this widespreadEurasiangenus south of
Warbler. The bird weighed 7.7 g at capture, had no
Alaska.
fat, and was measuredand photographed (Fig. 1).
After severaldaysof clear skiesand strongnorth Additional photosare on file with the California Bird
to northwest winds, the morning of 27 September Records Committee of the Western Field Ornitholobrought 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
(CAS70314)and wasconfirmed
dula), and Golden-crownedSparrows(Zonotrichia
atri- 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 (Zonotrichia leucophrys
pugetensis),
and one Rusty Song
Sparrow(Melospizamelodiamorphna).
This speciesassemblagestronglyimplied a northwesterncoastalorigin for the wave, although at least 10 individuals of
various "eastern" wood warblers also appeared that
day.
Around 0945, Pyle joined Brian Pendleton, who
was puzzling over a strangecall note emerging from
had no molt, a partiallypneumaticizedskull, and minute ovaries.The upper mandiblewas entirely dark
and the lower was dark with a yellow base.The legs
were dark brownish-graywith yellow soles.The eye
some low scrub near the east end of the island.
The
note, transcribedas "tchk" or "chak," was striking
for its loudnessanddryness;
it seemedespeciallyodd
after
the bird
was flushed
and found
to be a small
wood warbler-like passerine.The bird was chasedfor
about 3 rain, but a view adequatefor identification
was not obtained
because of the bird's
furtive
habit
of seekingout low thick cover.Only "nervous"wing
and tail flicking, a buff-white supercilium, and dull
was dark olive-brown.
Some measurements
were: ex-
posedculmen, 7.5 ram; culmen from nostril, 6.7 ram;
tarsus,27 ram; flattened wing, 62 mm; and tail, 49
The Dusky Warbler breedsin central USSR from
the Ob River eastto the Anadyr Basin(Williamson
1962) and winters in the Himalayasand southeast
Asia. Ticehurst (1938) recognized two races,the nominate, which is found over mostof the species'range,
and a darker, more resident Himalayan form, P. f.
weigoldi.The specieshas a fairly good potential for
vagrancyasevidencedby at least35 documentedwest
European recordsbetween 1958 and 1980 (Svensson
pets.comm.).There have alsobeen three occurrences