October 1992] ShortCommunications and Commentaries 923

Schnell for comments on earlier versions of this toparasitismas a problem of prey choice:A study manuscript.T.I.W. thanksJ. N.M. Smith for helpful on mudflat-feeding curlews, Numeniusarquata. adviceduring the early stagesof this study.E.J.T.'s Anim. Behav. 39:219-230. researchin Canadawas supportedby a NATO/NSF GRUBB,T. C., JR. 1977. Weather-dependent foraging PostdoctoralFellowship (RCD-8854487). in Ospreys.Auk 94:146-149. HANSEN,A. J. 1986. Fighting behavior in Bald Ea- LITERATURE CITED gles:A test of game theory. Ecology67:787-797. KNIGHT,R. L., AND S. K. SKAGEN. 1988. Agonistic ALATALO,R.V. 1982. Effectsof temperatureon for- asymmetriesand the foraging ecology of Bald aging behaviourof small forestbirds wintering Eagles.Ecology 69:1188-1194. in northern Finland. Ornis Fenn. 59:1-12. PETIT,D.R. 1989. Weather-dependentuse of habitat BILDSTEIN,K. L. 1987. Behavioralecology of Red- patchesby wintering woodland birds. J. Field tailed Hawks (Buteojamaicensis), Rough-legged Ornithol. 60:241-247. Hawks(B. lagopus),Northern Harriers(Circus cy- RYAN, B. F., B. L. JOINER,AND T. A. RYAN, JR. 1985. aneus),and AmericanKestrels (Falco sparverius) in Minitab handbook, 2nd ed. Duxbury Press,Bos- south central Ohio. Ohio Biol. Surv. Biol. Notes ton. 18:1-53. SCHNELL,G. D. 1968. Differential habitat utilization BILDSTEIN,K. L., ANDM. W. COLLOPY.1985. Escorting by winteringRough-legged and Red-tailed hawks. flight and agonistic interactionsin wintering Condor 70:373-377. Northern Harriers. Condor 87:398-401. STALMASTER,M. V., AND J. A. GESSAMAN. 1984. Eco- BROCKMANN,H. J., ANDC. J. BARNARD.1979. Klep- logical energeticsand foraging behavior of over- toparasitismin birds. Anim. Behav. 27:487-514. wintering Bald Eagles.Ecol. Monogr. 54:407-428. CLARK,R. J., AND J. G. WARD. 1974. Interspecific TEMELES,E.J. 1987. The relative importance of prey competitionin two speciesof open country rap- availabilityand intruder pressurein feeding ter- tors Circuscyaneus and Asiofiammeus. Proc. Pa. ritory size regulation by harriers, Circuscyaneus. Acad. Sci. 48:79-87. Oecologia74:286-297. DUGAN,P.J. 1982. Seasonalchanges in patchuse by TEMELES,E. J. 1990. Interspecific territoriality of a territorialGrey Plover:Weather-dependent ad- Northern Harriers: The role of kleptoparasitism. justmentsin foraging behaviour. J. Anim. Ecol. Anim. Behav. 40:361-366. 51:849-857. ENS,B. J., P. ESSELINK,AND L. ZWARTS.1990. Klep- Received4 September1991, accepted 8 March 1992.

The Auk 109(4):923-928, 1992

Pterylographyof Birds-of-paradiseand the SystematicPosition of Macgregor'sBird-of-paradise (Macgregoria pulchra)

MARY H. CLENCH Divisionof Gastroenterology,G-64, Department of InternalMedicine, TheUniversity of TexasMedical Branch, Galveston, Texas 77555, USA

Macgregor'sBird-of-paradise (Macgregoria pulchra) the treesare fruiting, the high mountainswhere Mac- is a poorly known speciesthat occurshigher in the gregorialives are difficult of accessand the birds dis- mountainsof New Guineathan any other memberof appear to unknown habitat when Dacrycarpusis not its family (Gilliard 1969,Cooper and Forshaw1977). fruiting (Beehler 1991). Macgregoriawas originally discoveredin 1896 and Becausethe speciesis little studied and rare in col- observationson itsbreeding behavior were first made lections,knowledge of the morphologyof Macgre- by Rand(1940), who locatedthe speciesin 1933and goriais limited.When Bock (1963) published a study 1938. More recently, Beehler(1983, 1991) visited its of the Paradisaeidaebased on skull morphologyand habitaton severaloccasions and reported on the spe- jaw musculature,no specimenof Macgregoriathen cies'behavior and ecology.As far as is known, Mac- existedin alcohol;Bock's only materialfor thatgenus gregoriahabitat is cloudforest and subalpineDacry- was a skull taken from a studyskin. He found that, carpus(Podocarpus) forest at the edge of alpine within the family, Macgregoriawas the only genus grasslandsbetween 2,800 and 4,000m. Althoughthe thatdid notclearly fall into eitherthe large subfamily speciesappears to be sedentary,relatively easy to ob- of typicalbirds-of-paradise (Paradisaeinae) or the small serve,and fairly commonin Dacrycarpusgroves when group (Cnemophilinae)that Bockproposed for Cne- 924 ShortCommunications and Commentaries [Auk, Vol. 109

for morphologists,one individual caughtin a net was accidentallykilled by a dog and, thus,was preserved in formalin: USNM No. 541230, an adult male from PapuaNew Guinea,Northern Province,English Peaks, 3,650 m (8ø46'S,147ø29'E); 23 July 1986;testes 3 x 2 o'o obo ram), mass 253 g, no molt. I am grateful to B. M. c• o o a o•o Beehler and to S. L. Olson of the National Museum o' a' a' o, 'a ,o •a k, of Natural History for being allowed to skin and ex- amine this and other recently obtainedmaterial. d • o'• a • ; k •x PARSDORSALIS When I publisheda study of the body pterylosis (feathertracts) of the birds-of-paradise(Clench 1985), my seriesof specimensincluded all the known genera of the family exceptMacgregoria, Lycocorax, and Drep- anornis.Drepanornis, an undoubtedmember of the Par- o• o o • • O o 'D o •O o adisaeinae,remains unavailable, but with a recently oo•o•o•oo collected specimen of Lycocorax(USNM No. 507559) and a better specimenof Loboparadisaea(a cage bird from the National ZoologicalPark; USNM No. 507321), a fairly completerecord of the body pterylosisof the • PARS PELVICA family is now available. I also thank M. LeCroy of the American Museum of Natural History, who ar- ranged to lend me a recently collectedspecimen of I Melampitta(AMNH No. 4384), a New Guinea "log- runner" that Sibleyand Ahlquist(1990) found to be Fig. 1. Diagrammaticrepresentation of Pteryla a primitive paradisaeid. Spinalisin Macgregoriapulchra. Individual feathersof In this study, I have followed the flat-skin tech- pars dorsalisare indicatedby circles,those of first nique previouslydescribed (Clench 1970, 1985),ex- row of pars pelvica as triangles. amining the underside of a skin with a binocular dissectingmicroscope (10-40x). The pterylae stud- ied and pterylographicterminology used here are the sameas in Clench (1985).In brief, the Pteryla Spinalis mophilus,Loria, and Loboparadisea.Macgregoria shared (the Dorsal Tract of Clench 1970) extends down the manyskull characterswith the cnemophfiines,but dorsal surface from the base of the skull to the uro- also had a few that were similar to the true birds-of- pygial gland. It containsthree parts:the pars inter- paradise.Bock concludedthat Macgregoriawas most scapularis(formerly, anterior element), a narrowband similarto the Cnemophilinaeand includedit in that of feathersextending down the midline of the body subfamily. from the baseof the skull to the upper back; the pars Mayr (1962)recognized the subfamilialdivisions, dorsalis(saddle), an expanded area of feathering that butalthough he wasfamiliar with Bock's(1963) study covers the back; and the pars pelvica (posterior ele- and noted that the genus might belong in the Cne- ment), a narrow band that coversthe rump. The Pter- mophilinae,he placedMacgregoria as the first genus yla Ventralis(Ventral Tract) is composedof a mirror- of the Paradisaeinaefor Peters'Check-list. Perhaps be- image double band of feathers covering the breast causeMacgregoria is large-bodied and almostsolidly and abdomen on either side of the midline. It contains black,but with orange-yelloweye wattlesand wing two parts:the pars pectoralis(flank element) and the patches,and Paradigallais alsolarge and blackwith parsabdominalis (main element). In mostpasse fines, yellow wattlesat the baseof the upper mandible, the PterylaSpinalis, especially the parsdorsalis, shows Mayr (1941)had placedthe two generabetween the more variation and, therefore, is of the greatest tax- similarlylarge but all-black Manucodia and Phonygam- onomic interest. mus in an earlier work on the New Guinea avifauna. Macgregoriais uniformly heavily featheredin the Mayrmay have been more persuaded by Macgregoria's Pteryla Spinalis. The central pars dorsaliscontains 10 outwardappearance than by itscranial characteristics. chevron-shapedrows, with a total of 158 feathers(Fig. Sincethe early 1960s,therefore, the systematicpo- 1). The featheringis closelyarranged with no sug- sition of the genushas remainedin question.Prob- gestion of a spaceor apterlure at the junction of the ably becausefurther evidence has not becomeavail- pars dorsalisand pars pelvica, which is also heavily able, mostsubsequent authors have followed Mayr's feathered.The Pteryla Ventralis hasa maximum width placement(e.g. Schodde1976). of eight feathersand the separationbetween the pars During his field studiesof Macgregoria,Beehler pectoralisand pars abdominalisis three or four rows (1983,1991) color-tagged and attached radios to a few long;the parsabdominalis had losttoo many feathers birds to follow their daily movements.Fortunately to count. October 1992] ShortCommunications and Commentaries 925

TABLE1. Dorsal pterylosisof Paradisaeidae?

Pteryla Spinalis, pars dorsalis No. specimens Taxon No. rows No. feathers Basalgap examined Cnemophilinae Loria 13 225, 254 No 2 Loboparadisea 13 245 No 2 Cnemophilus 13 -- No 2 Macgregoria 10 158 No 1 Melampitta 12 254 Yes 1 Paradisaeinae Lycocorax 8 115 Yes 1 Manucodia 8 92, 116 Yes 3 Phonygammus 7 105 Yes 1 Ptiloris 9 147 Yes 1 Semioptera 7 89 Yes 1 Seleucidis 7 97 Yes 1 Paradigalla 7 -- Yes 1 Epimachus 10 172,180 Yes 2 Astrapia 11 200,201 Yes 2 Lophorina 8 119 Yes 1 Parotia 10 142 Yes 1 Pteridophora 10 150 Yes 1 Cicinnurus 7 83 Yes 1 Diphyllodes 8 102,128 Yes 2 Paradisaea 9, 10 144, 155 Yes 3

Datafor all exceptMacgregoria, Melampitta, Lycocorax, and Loboparadlsaeafrom Clench(1985).

Lycocoraxis much more lightly feathered,showing in the flank-plumed paradisaeines(especially Para- the pattern typicalof the Paradisaeinae;the parsdor- disaea),the tract is unremarkable in both subfamilies salishas 115 feathersin eight rows. There is a small (Clench 1985).Cnemophilines have a maximumwidth but distinct apterium at the baseof the pars dorsalis of nine feathers,the separationbetween the two pars (the central feather of row 8 is absent). The pars pel- is three or four rows long, and most of the rows of vica is similarly weakly feathered,with 12 short rows the pars abdominalis contain four feathers. Paradi- of mostlyfive featherseach. saeines have a maximum width of 7 to 10 feathers (11 Loboparadisaeais typically cnemophiline, with heavy to approximately28 in the flank-plumedforms), the plumage (245 feathersin 13 rows) and no gap or ap- separationis from three to seven rows long (again, teriumat the baseof the parsdorsalis. The parspelvica longer separationsare associatedwith the specialized is also heavily featheredbut too damagedto count. flank plumes), and the abdominal rows contain 3 to The Paradisaeinaeare characterizedby a relatively 5 feathers.Macgregoria does not differ in any impor- small and sparselyfeathered pars dorsalis(Clench tant way from either subfamilyin this tract. 1985). In addition, at the junction between the pars Figure 2 showsthe general correlationbetween the dorsalisand the pars pelvica is a small gap which is number of rows and number of feathersin the Pteryla universal in the Paradisaeinae but found in none of Spinalis,pars dorsalis,based on data from all birds- the Cnemophilinae(Table 1). The three acceptedgen- of-paradisestudied. Not surprisingly,the specieswith era of Cnemophilinaeare generally small birds-of- more rows also contain more feathers in the pars. paradiseand, like Macgregoria,are also uniformly Macgregoria(asterisk) is intermediatein both number feathered,but more heavily. The pars dorsalisis 13 of rows and number of feathers. rows long in them all and containsfrom 225 to 254 As indicatedby wing length (Fig. 3A), generalbody feathers in the two Loria and one Loboparadiseathat sizeof Macgregoriais large,falling within the range could be countedfully. The wide range of body sizes of the Paradisaeinae.The genus also falls in or near in the Paradisaeinaeprobably accounts for the equally the high rangeof the Paradisaeinae,but closerto the wide range found in that subfamilyin the number valuesof the Cnemophilinaein numbersof rows (Fig. of rows (7 to 11) and the number of feathers (83 to 3B) and feathers (Fig. 3C) in the pars dorsalis.More 201) in the pars dorsalis. importantly, in my experience,is the fact that the Unfortunately, the Pteryla Ventralis of the Para- pattern type (with a basal apterium or gap) agrees disaeidae adds little useful information. Aside from with that of the Cnemophilinae (Table 1). Patterning the extraordinarydevelopment of the pars pectoralis in pterylaeand, to a lesserextent, the degree(heavi- 926 ShortCommunications andCommentaries [Auk,Vol. 109

14- I A Macgregor•a 12- J I I I Paradisaemae

I Gnemophlhnae

I I i I I I I i i i GO 80 100 120 140 160 180 200 220 240 6 I I I I I I I I 80 lOO 120 140 160 180 2OO 22O 24O 26O Wing Length (mm) Number of Feathers a I Fig. 2. Number of feathersversus number of rows Macgregoria in pars dorsalis of Paradisaeidaegenera examined. The two pointsin upper right representCnemophil- Paradisaelnae inae; asteriskrepresents Macgregoria. I Cnemophlhnae ness)of feathering are conservativewithin the Pas- I I I I I I I I seriformes(Clench 1970, 1985);in other families, pat- 2 4 6 8 10 12 14 16 tern differenceslike those between Macgregoriaand Number of Rows the Paradisaeinaehave proved to be important dis- tinctions supportedby other morphologicalcharac- c I ters (e.g. Ames et al. 1968). Convergenceof Macgre- Macgregor•a goriawith someof the Paradisaeinaein certainaspects

(such as numbers of rows and feathers) may result Paradisaeinae from similarity in body size. In his extensive studies of birds-of-paradise,Beeh- Cnemophilinae ler (1983) pointed out that Macgregoriadiffers from most or all of the Paradisaeinaein having a limited I I I I 0 100 200 300 vocal repertoire,in being monomorphicand monog- Number of Feathers amous,in maintaininga strongpair bond throughout the year by continued ritualized behavior patterns Fig. 3. Comparisonof Macgregoriawith data for and by closephysical contact(members of a pair al- Paradisaeinaeand Cnemophilinae:(A) wing length; lopreen), and in being a fruit specialist.Later work (B) number of rows in pars dorsalis;(C) number of (Beehler1991) suggests that the lastcharacteristic may feathers in pars dorsalis. For the two subfamilies, not hold at all times.Although the femalealone builds means (vertical line) and two standard deviations the nest and incubatesthe single egg, she is closely (horizontal line) indicated. accompaniedby the malethroughout that period,and he appearsto take the majorpart in feeding the chick. Even when fully grown, a juvenile remains with its Phonygammusdiffer from Macgregoriabehaviorally by parents,begging for food asthe adultsforage togeth- their having a vocal repertoire of loud callsand com- er. A pair of birds has also been shown to occupya plex songs.They also differ morphologicallyin hav- home range of about 12 ha, where fruit other than ing highly specialized,strikingly elongatedtracheas that of Dacrycarpusis eatenwhen the favoredfood is (Clench 1978). Table 1 also showsthat, typical of the not immediately available (Beehler 1991). pterylosisof their subfamily, Lycocorax,Manucodia, Of the speciesof Paradisaeinaethat Macgregoriais and Phonygammusall have relatively few feathersin placednext to in mosttaxonomic lists (e.g. Mayr 1962; sevenor eight rows with gappingat the baseof the see Table 1), Lycocorax(a Moluccan genus whose bi- pars dorsalis,which is clearly different from the con- ologyis almostunknown), Manucodia, and Phonygam- dition in Macgregoria. musare also monomorphicin plumage. As far as is In addition, Macgregoriashares several traits with known,Phonygammus, Manucodia, and Macgregoria have the Cnemophilinae,although the biology of species relatively similar breeding behavior that includes in that subfamilyis poorly known: all are monoga- monogamy,simple courtship,and someparticipation mous,have relatively simple courtshipbehavior, and by the male in raisingthe young.Manucodia and Pho- are frugivorous(Beehler 1985, Gilllard 1969).The cne- nygammusare fruit specialists(on figs),but until fur- mophilines, however, are sexually dimorphic, but ther field work can show what Macgregoriafeeds on without the plumes and other specialized ornate during periodswhen Dacrycarpusfruits are not avail- feathering of paradisaeines. able, its statusas a fruit specialist(Beehler 1983) re- It is unfortunate that the rarity of Macgregoriama- mains to be confirmed. In addition, Manucodia and terial has limited the knowledge of its morphology October1992] ShortCommunications andCommentaries 927 and other factors that would contribute to a better mediate between the Cnemophilinae and the Par- understanding of its systematicposition. Borecky adisaeinae.Based on our respectiveexperiences with (1977) did not have a specimenfor his study of the the characters under consideration, however, ! also appendicularmyology of the Paradisaeidae;Borecky agree with Bock (1963) that Macgregoriais more like did, however, supportthe division of the family into the Cnemophilinae and should be included there, at the primitive Cnemophilinaeand morehighly evolved leastuntil further evidencecan clarify the relation- Paradisaeinae(Cooper and Forshaw 1977).Similarly, ship. On balance,behavioral data also support the Sibley and Ahlquist (1990) have examined neither placementof Macgregoriain the Cnemophilinae.The Macgregorianor any of the cnemophilines,although comparatively great body size differencesbetween they did find strong similarities among Epimachus, Macgregoriaand the generaaccepted to be cnemophi- Astrapia,Cicinnurus, Diphyllodes, Pteridophora, Ptiloris, lines may be due to convergencewith others in the and Paradisaea,and a clear divergencebetween that family. Melampittamay well be anotherintermediate sexuallydimorphic group and Manucodia.They also form of bird-of-paradiseand relatedto Macgregoria. found that the monomorphic,terrestrial Melampitta-- heretoforecustomarily considered a logrunner (Musc- LITERATURE CITED icapidae, Orthonychinae; Deignan 1964)--was a primitive bird-of-paradise.This may well be the case. AMES, P. L., M. A. HEIMERDINGER,AND S. L. WARTER. My examinationof the pterylosisof a specimenof 1968. The anatomy and systematicposition of Melampittalugubris (prompted by Mary LeCroy after the antpipits Conopophagaand Corythopis.Postilia she refereed the present paper) showed a clear sim- No. 114. ilarity between the feather tracts of this small, all- BEEHLER,B. M. 1983. Notes on the behaviour and blackNew Guineaspecies and typicalcnemophilines, ecologyof Macgregor'sBird of Paradise.Emu 83: yet also with paradisaeinecharacters. The pars dor- 28-30. salis is heavily feathered in 12 rows with a total of BEEHLER,B. M. 1991. A naturalist in New Guinea. 254 feathers,but unlike Macgregoriaand the accepted Univ. Texas Press, Austin. cnemophiline genera, and like the Paradisaeinae, BOCK,W. J. 1963. Relationshipsbetween the birds Melampittaalso has a small gap (the equivalent of a of paradise and the bower birds. Condor 65:91- singlemidline feather) at the baseof the parsdorsalis, 125. and a weak pars pelvica. The latter contains10 chev- BORECK¾,S.R. 1977. The appendicularmyology and ron-shapedrows, predominantly with three feathers phylogeneticrelationships of the avian "corvid exceptfor the last 3 or 4 rows which are longer and assemblage." Ph.D. dissertation, Univ. Pitts- form an expandedbase for the tract.The PterylaVen- burgh, Pittsburgh,Pennsylvania. tralis has a maximum width of 9 or 10 feathers, the CLENCI•,M.H. 1970. Variability in body pterylosis, separationbetween the pars pectoralisand pars ab- with special reference to the genus Passer.Auk dominalisis 2 rows long, and the rows in the pars 87:650-691. abdominalisare five or six featherslong. In Melam- CLENCH,M. H. 1978. Tracheal elongation in birds- pitta, therefore, we find another form that is inter- of-paradise.Condor 80:423-430. mediate between the two subfamilial types of the CLENCH,M.H. 1985. Body pterylosisof Atrichornis, Paradisaeidae.Unfortunately, the pterylosisof or- Menura,the "corvid assemblage,"and other pos- thonychine genera is not yet well known. Nitzsch sibly related passerines(Aves: Passeriformes). (1867) and Forbes(1881) reported that Cinclosomaand Records of the Australian Museum 37:115-142. Eupetesmacrocercus, respectively, had the "typical pas- COOPER,W. T., AND J. M. FORSHAW. 1977. The birds serine" pattern, an expanded pars dorsaliswithout a of paradiseand bower birds. Collins, Sydney. central apterium (a description ! doubt that either DEICNAN,H. G. 1964. Family Muscicapidae,Subfam- man would have applied to Melampitta).! have not ily Orthonychinae. Pages228-240 in Check-list yet examined any logrunners,but timaliines (Leio- of birds of the world, vol. 10 (E. Mayr and R. A. thrix,Stachyris) agree with the categorizationused by Paynter, Jr., Eds.). Museum of Comparative Zo- Nitzschand Forbes.Clearly, Melampitta deserves fur- ology, Cambridge,Massachusetts. ther investigation, and DNA-DNA hybridization FORBES,W.A. 1881. Note on the systematicposition studiesof this genus and both subfamiliesof birds- of Eupetesmacrocercus. Proc. Zool. Soc.Lond. ! 88!.' of-paradise would be useful. After their recent field 837-838. studiesof Melampittalugubris, Frith and Frith (1990) FRITH,C. B.,AND D. W. FRITH. 1990. Nestingbiology suggestedthat if the speciesis a bird-of-paradise,its and relationshipsof the LesserMelampitta Mel- nestingbiology indicatesa much closerrelationship ampittalugubris. Emu 90:65-73. to the cnemophilines, and particularly Cnemophilus GILLIARD,E. T. 1969. Birds of paradise and bower (Macgregoria),than to the paradisaeines. birds. Natural History Press,Garden City, New In summary, pterylography adds additional evi- York. denceto Bock's(1963) cranial data and supportto his MAYR, E. 1941. List of New Guinea birds. American conclusionthat Macgregoriais morphologicallyinter- Museumof Natural History, New York. 928 ShortCommunications andCommentaries [Auk, Vol. 109

M^YR,E. 1962. Family Paradisaeidae.Pages 181-204 $CHODDE,R. 1976. Evolutionin the birds-of-paradise in Check-list of birds of the world, vol. 15 (E. and bowerbirds,a resynthesis.Pages 137-149 in Mayr and J. C. Greenway, Jr., Eds.). Museum of Proceedings 16th International Ornithological Comparative Zoology, Cambridge, Massachu- Congress(H. J.Frith and J. H. Calaby,Eds.). Can- setts. berra,1974. Australian Academy of Science,Can- NITZSCH,C.L. 1867. Pterylography(P.L. Sclater,Ed.). berra. Ray Society,London. SIBLEY,C. G., AND J. E. AHLQUIST.1990. Phylogeny R^I•D, A. L. 1940. Breeding habits of the birds of and classification of birds. Yale Univ. Press, New paradiseMacgregoria and Diphyllodes.Results of Haven, Connecticut. the Archbold Expeditions.No. 26. Am. Mus. No- vit. 1073. Received3 October1991, accepted 8 March 1992.

The Auk 109(4):928-933, 1992

Differences in Song and Sexual Dimorphism between Cuban and North American Red-winged Blackbirds (Agelaius phoeniceus)

LINDA A. WHITTINGHAM, 1 ARTURO KIRKCONNELL,2 AND LAURENE M. RATCLIFFE1 •Departmentof Biology,Queen's University, Kingston, Ontario K7L 3N6, Canada;and 2MuseoNacional de HistoriaNatural, CapitolioNacional, La Habana,Cuba

In many speciesof birds, song is characteristicof The songsof Cuban Red-wingedBlackbirds were the male (Nottebohm1975). However, an increasing recorded in the Zapata Swamp at Treasure Lake number of studieshave also found that femalessing (22ø10'N;81ø50'W) during 9-10 April 1991. In Cuba, (reviewed in Farabaugh1982, Ritchison 1983). Usu- the birds were observed in bottle-brush trees (Calliste- ally, in such cases,male and female songsare dis- monspeciosus) and tall grasses(Phragmites spp.) at the tinctly different in structure but have similar func- periphery of the lake. Two birds were observedcar- tions, such as territory advertisement and defense rying strips of vegetation, which suggestedthat April (Armstrong1963, Farabaugh 1982, Ritchison 1983). In was the beginning of the breeding seasonfor Cuban temperatespecies, female song is relativelyrare; how- Red-winged Blackbirds. Temperate Red-winged ever, it is more common in tropical species,where Blackbird songs were recorded between April and femalesoften duet with their mates(Farabaugh 1982). June 1991 near Kingston, Ontario, Canada (44ø33'N; Red-winged Blackbirds(Agelaius phoeniceus) are one 76ø20'W). In Ontario, males were associated with of the few known speciesin which malesand females breeding territories in cattail (Typha spp.) marshes, sing different songsin temperate populations (Belet- similar to other populationsthroughout North Amer- sky 1983,Searcy 1989a), whereas pairs duet in a trop- ica (Nero 1956, Orians 1980). ical population (Farabaugh1982, E. S. Morton pers. Songs were recorded with an Audio-technica comm.).This intraspecificvariation providesan op- AT815a directional microphone and Sony Profession- portunity to study the adaptive function of song and al cassetterecorder. Sonagramswere analyzed on a other sexuallyselected characteristics, such as plum- Kay ElemetricsDSP SonagraphModel 5500, using a age and body size. 16-kHz frequencyaxis with a 512-pointtransform (117- We comparedsexual differences in song, plumage Hz band-passfilter) and a time axis of 2 s with a and body size between temperateRed-winged Black- 200-point transform (300-Hz band-passfilter). We an- birds in easternNorth America(A. p. phoeniceus)and alyzed duets of pairs in Cuba and solo songsof in- tropical Red-winged Blackbirds in Cuba (A. p. assi- dividuals in Cuba and North America. We considered milis).Red-winged Blackbirdsbreed throughout most a duet as one pair of songs,one song producedby of North and Central America; the distribution of A. eachsex, overlapping or lessthan I s apart, and given p. phoeniceusextends from north-central Ontario to repeatedlyin sequence(e.g. Farabaugh1982; Fig. 1). northern Florida and from the Mississippi River to Duets were performed by one male and one female the Atlantic Ocean (Peters 1968,Power 1970),whereas perched0.5 to 2.0 m apart. In mostcases the male was A. p. assimilisis endemic to the western part of Cuba perchedabove the female and they were facing each (Peters1968, Garrido 1970,Bond 1985).In this paper other. For simplicity we refer to a duetting male and we show that Cuban Red-winged Blackbirds exhibit female as a pair; however, it was not known whether relatively lesssexual dimorphism in song, plumage the two individuals were mates. Songsgiven in se- and body size than North American Red-winged quence by the same individual, but not closely fol- Blackbirds.We proposea hypothesisto accountfor lowed by the songof anotherindividual, were con- thesedifferences and suggesta possibletest. sidered solo songs. For solo songs the following