SHORT COMMUNICATIONS 179 that some substantialfraction of the males present in cappedVireo in the United Statesis inextricably linked the transectarea were not counted, the estimated pop- to the Mexican population of this . A full under- ulation size would be increasedproportionally. standingof the species’status requires much more work We drove many miles of mountainous back roads in Mexico. throughout the censuszone. We examined (with bin- oculars)openings to many canyonswhich appearedto LITERATURE CITED contain vegetation similar to that found in canyonswe BARLOW,J. C. 1967. Nesting of the Black-capped surveyed. We believe our estimate that 40% of the Vireo in the ChisosMountains, Texas. Condor 69: region is structurally similar to the four canyons we 605-608. sampled is conservative. Our survey sites were not CCKZH~AN,W. G. 1977. Sampling techniques. John chosenbecause we suspectedBlack-capped Vireos were Wiley and Sons, New York. present. We chose the four sites becausewe had ob- GRABER,J. W. 1961. Distribution, habitat require- tained permission to enter them from local ranchers. ments, and life history of the Black-cappedVireo If this large population of Black-cappedVireos does (Vireo atricapilla). Ecol. Monogr. 3 1:313-336. exist in northern Mexico in a relatively small area, why GRZYBOWSKI,J. A., R. B. CLAPP,AND J. T. MARSHALL, is the population in Texas and Oklahoma so reduced? JR. 1986. History and current population status The are believed to be associatedwith a transi- of the Black-cappedVireo in Oklahoma. Am. Birds tional type of habitat (Graber 1961) characterized as 40:1151-1161. “scrub oak growth of irregular height and distribution MARSHALL,J. T., R. B. CLAPP,AND J. A. Gnzvaowsxr. with spacesbetween the small thickets and clumps” 1985. Status report: Vireo atricapillus Wood- (Grzybowski et al. 1986). In contrast, we commonly house, Black-cappedVireo. Office of Endangered found vireos in Mexico in densethickets with few spaces Species, U.S. Fish and Wildlife Service, Albu- between clumps of vegetation. These extensive scrub querque, NM. thickets may have resulted from the frequent uncon- MILLER,A. H. 1955. The avifauna of the Sierra Del trolled wildfires which sweep through the canyons in Carmen of Coahuila, Mexico. Condor 57:154-178. this part of Mexico. This dense habitat type is uncom- MULLER,C. H. 1947. Vegetation and climate of Coa- mon in Texas and Oklahoma possibly owing to more huila, Mexico. Madrofio 9: l-32. intensive ranching and development in these states. PHILLIPS,A. R. 1974. Summary of avian resources We suggestthat a denser structure with fewer open of the Chihuahuan Desert region, p. 611-620. In spacesmay be better suited to breeding Black-capped Transactionsof the symposium of the biological Vireos and that this structure,along with lessintensive resourcesof the ChihuahuanDesert region,United ranching and fewer cowbirds accountsfor a far larger Statesand Mexico. Sul Ross State Univ.. Amine. population in northern Coahuila than in areas of sim- TX. ilar size in Texas. STEED,D. L. 1988. The Black-capped Vireo (Vireo In speakingof this region of Mexico, A. R. Phillips atricapillus) in Travis County, Texas. Technical (1974) says,“One may travel past range after range of Brief, DLS Associates,Austin, TX. mountains, and arroyo after arroyo, in which no or- nithologist has ever set foot.” The fate of the Black-

The Condor92:779-781 0 The Cooper Ornithological Society 1990

AN OBSERVATION OF SOCIAL PLAY IN BEARDED ’

DANIELT. BLUMSTEIN Behavior Graduate Group, % Department of Zoology, Universityof California, Davis, CA 95616

Key words: Socialplay; Bearded ;Gypaetus patternsfrom other contextsmay often be usedin mod- barbatus;Pakistan; . ified forms and altered temporal sequencing” (Bekoff and Bvers 1981. D. 300). This note describesan ob- Play behavior has been defined as “all postnatalmotor servation that I interpreted to be social play (play di- activity that appearsto be purposeless,in which motor rectedtowards another individual) in BeardedVultures (Gvuaetus._ barbatux ). Obiect olav has been inferred in Bearded Vultures (Fagen 198l)- when in- dividuals drop and catchbones in the air (Olivier 1961, ’ ’ Received 15 November 1989. Final acceptance22 Huxley and Nicholson 1963)and when they drop stones February 1990. from the air (Povolny 1966). I have found no reports 780 SHORT COMMUNICATIONS of social play in this speciesor other Old World vul- by reassuringparticipants that they are indeed playing tures, and observations of play in birds appear to be (Bekoff 1978). I suggestthe repeated high-pitched vo- underreported (Fagen 1981). calization heard was a play signal. At 08:45 on 9 September 1989, I observed two im- Socialplay is expectedin birds like BeardedVultures mature Bearded Vultures flying together and calling for several reasons (Ortega and Bekoff 1987). They about 50 m below me at Dhee Sar (36”8 1’N. 74”95’E) mature slowly, remaining in subadult plumage for 5 in Khunjerab National Park, Pakistan. Dhee Sar is a years (Dement’ev and Gladkov 1966). Courtship relatively flat high alpine meadow (elevation 4,1 OO- “practice” might improve skills required later in life. 4,300 m) surrounded by steep lateral moraines and Practice chasingconspecifics under low-risk situations punctuated with hilly terminal moraines. I observed might be beneficial for later chasesof heterospecifics. the birds from a ridge above the meadow using 10 x For example, Fleming et al. (1984) described Bearded 40 binoculars and a 15-45 power spotting scope. The Vultures chasing Himalayan Griffon Vultures ( birds were easily discriminated by feather-loss pat- himalayensis)in the air. Also, since Bearded Vultures terns. For the next 12 mitt, I watched the two birds may live in large groups (Brown and Amadon 1968), take turns chasingeach other. One would glide up to play might be important for social cohesion (Fagen within a meter of the tail of the other, and then the 1981). roles were reversed. Sometimes they dived, one still I thank M. Bekoff, J. Marzluff, W. Shriner, T. Rob- chasing the other. This activity was accompanied by erts, and an anonymousreviewer for helpful comments little flapping. On no occasiondid I observe physical on a previous version of this manuscript. I also thank contact, nor did I observe any objects carried in their the Pakistan National Council for Conservation of talons. My observation of the two birds ended when Wildlife and the director of Khunjerab National Park they flew out of sight behind a mountain. for permission to work in Pakistan. Fieldwork was A high-pitched prolonged whistle accompaniedthis generously supported by grants from The Explorers behavior. The one note whistle was repeatedwhile the Club, and a University of California, Davis Graduate two birds were close to each other. I recorded this Research Award and Jastro-Shields Graduate Re- vocalization, but backgroundwind noise prevented me searchScholarship. from oroducinaa cleansonoaram. Ah and Riolev (1987. p. 79) reported that Bearded Vultures utter a “sharp LITERATURE CITED guttural koolik, koolik” during aerial courtship dis- plays, but they otherwise rarely vocalize. The voice of ALI, S., AND S. D. RIPLEY. 1987. Compact handbook a Bearded Vulture has also been describedas a “whis- of the birds of and Pakistan together with tle” or “mew” (Dement’ev and Gladkov 1966, Flint thoseof Bangladesh,Nepal, Bhutanand Sri Lanka. et al. 1984) or a “guttural hiss” (Fleming et al. 1984). 2nd ed. Oxford Univ. Press. Delhi. My observationhas at least three mutually exclusive BEKOFF,M. 1978. Social pla< structure, function, interpretations.First, the BeardedVultures could have and the evolution of a cooperativesocial behavior; been courting. The breedingseason in Asia for Bearded D. 367-383. In G. M. Burzhardt and M. Bekoff Vultures is between November and March (Lowther ieds.], The development of behavior: comparative 1949, Ah and Ripley 1987). Ah and Ripley (1987) and evolutionary aspects.Garland STPM Press, reported acrobaticdisplays around the beginningof the New York. breeding season.Dement ’ev and Gladkov (1966) re- BEKOFF, M. 1984. Social play behavior. Bioscience ported nuptial flights at the end of January or the be- 34:228-233. ginning of February which included aerial displays. I BEKOFF,M., AND J. A. BYERS. 1981. A critical re- reject the courtship hypothesis on three counts: the analysis of the ontogeny and phylogeny of mam- birds were both in immature plumage,early September malian social and locomotor play: an ethological seems to be too early for courtship displays based on hornet’s nest, p. 296-337. In K. Immehnann, G. the publishedrecords, and the vocalization was not the W. Barlow, L. Petrinovich, and M. Mains [eds.], “koolik, koolik” described by Ah and Ripley (1987) Behavioral development: the Bielefield it&d&- to accompany courtship displays. ciplinaty conference. Cambridge Univ. Press, Second,the birds could have been fighting or threat- Cambridge. ening each other. I reject this hypothesison two counts: BROWN,L. H., ANDD. AMADON. 1968. ,, there was never anv contact between the birds. and the and falconsof the world. McGraw-Hill, New York. birds alternated roies during the 12 min I observedthe DEMENT’EV,G. P., ANDN. A. GLADKOV. 1966. Birds interaction. of the Soviet Union. Vol. 1. Program for Finally, the birds could have been playing. I have Scientific Translation, Jerusalem. not been able to reject this hypothesis,and three of my FAGEN, R. 198 1. Animal play behavior. Oxford Univ. observations support this as the likely explanation of Press, New York. the observed behavior. First. the two birds were iu- FLEMING,R. L., SR., R. L. FLEMING,JR., AND L. S. veniles; play is most likely to be seen in juvenile ani- BANGDEL. 1984. Birds of Nepal with reference mals (Fagen 1981). Second, the behavior appearedre- to Kashmir and . 3rd ed. Nature Himala- ciprocal in that one bird was not always chasing the yas, Kathmandu. other-roles changed frequently. An important char- FLINT, V. E., R. L. BOEHME, Y. V. KOSTIN, AND A. A. acteristic of social play behavior is changesin chase- Ku-v. 1984. A field guide to the birds of flee relationships (Bekoff 1984). Third, social play is the USSR including Eastern Europe and Central often accompanied by play signals that may be im- Asia. Princeton Univ. Press, Princeton, NJ. portant, particularlyduring potentially dangerousplay, HUXLEY, J., AND E. M. NICHOLSON.1963. Lammer- SHORT COMMUNICATIONS 781

geier Gypaetusbarbatus breaking bones. Ibis 105: ORTEGA, J. C., AND M. BEKOFF. 1987. Avian play: 106-107. comparative evolutionary and developmental Lowrrma, E.H.N. 1949. The Lammergeier (GypaBus trends. Auk 104:338-34 1. barbatus)Linnaeus. J. Bombay Nat. Hist. Sot. 46: POVOLNY,D. 1966. Uber ein Spiel des Bartgeiers 501-508. (Gypaetusbarbatus). J. Omithol. 107:352-353. OLMER, G. 1961. Quebranta-huesos. Alanda 29: 226-227.

The Condor 9278 l-783 0 The CooperOrnithological Society 1990

A FORAGING ASSOCIATION BETWEEN TWO KITE SPECIES (ICTINEA PL UMBEA AND LEPTODON CA YANENSIS) AND BUFFY-HEADED MARMOSETS (CALLZTHRZX FLA VZCEPS) IN SOUTHEASTERN BRAZIL

STEPHENF. FERRAIU Department of Anthropology,University College, London and Departamentode Zoologia, Museu ParaenseEmilio Goeldi, Caixa Postal 399, 66.040 Bekm-PA, Brazil

Key words: Ictinea plumbea; Leptodon cayanensis; In addition to the main study, during which the be- Callithrix flaviceps;primates; foraging association. havior of an habituated marmoset study group (con- taining between 11 and 15 members) was recorded in Many insectivorous birds, notably those of the For- detail, less systematic observations of this and other micariidae (Willis and Oniki 1978), are known to sys- groups were begun in December 1984 and have con- tematically exploit the disturbance of prey caused by tinued sporadically up to the present day. The main the foragingactivities of other . Recent studies study involved the collection of scan sample records (Fontaine 1980, Terborgh 1983, Boinski and Timm of the behavior of the study group during at least 10 1985. Boinski and Scott 1988. Sieael et al. 1989) have days each month between August 1985 and August reported this type of foraging association between a 1986 (Ferrari 1988). All observed interactions with variety of Neotropical bird species and platyrrhine other animal specieswere recorded opportunistically. monkeys of the genera Saguinus(Callitrichidae), and RESULTS Cebusand Saimiri (Cebidae). The present report describesa foraging association Callithrixflavicepswas observed interacting with a range involving both Plumbeous(Ictinea plumbea) and Grey- of bird speciesas both potential prey and predator. The headed (Leptodoncayanensis) kites with groupsof buf- marmosets displayed an extensive repertoire of anti- fy-headed marmosets (Callithrixj7aviceps).The asso- predator behaviors, a majority of which was related to ciation is unusualin being restricted to both a specific the avoidance of raptors, whose characteristic flight type of prey (cicadas)and a particular time of year. profile provoked an intensereaction (Ferrari and Lopes Ferrari, in press). Medium-sized birds of prey, includ- STUDY SITE AND OBSERVATIONS ing Micrastur rujicollis(Izawa 1978) M. semitorquatus The association reported here was recorded during (Alonso and Langguth 1989), Spizaetusornatus (Daw- studies of the ecology of the bufly-headed marmoset son 1976, Goldizen 1987), and S. tyrannus (Dawson (adult body weight approximately 0.4 kg), carried out 1976), appear to be the principal predators of cal- in a privately owned reserve on the Fazenda litrichids. Callithrix flaviceus.in turn. was observed Montes Claros in Minas Gerais, southeasternBrazil feeding on eggsof the Rufous-collared Sparrow (Zo- (19‘50’s. 41”5O’w). The studv area was comoosed of notrichia capensis)on two occasionsand on an un- hilly secondaryand disturbed-foresthabitats bordered identified fledgling on a third occasion. on three sides by open fields and on the fourth by the The foraging associationswith both I. plumbea and less disturbed forest of the main body of the reserve. L. cayanensisrepresent a third, highly specific type of Rainfall at the site averages 1,145 mm annually, with interaction between the marmosets and birds. As ob- a clearly defined dry seasonnormally spanningthe pe- served in other bird/monkey associations,the kites ex- riod between April and September.For a more detailed ploited prey flushed by the marmosets during their description of both the study site and methodology, foragingactivities. Unlike other associations,however, see Ferrari (1988). this behavior was both highly seasonaland involved the captureofa singletype ofprey, large-bodiedcicadas (Homoptera: Cicadidae). I Received 15 November 1989. Final acceptance26 Mature cicadas were particularly abundant in the April 1990. study area during the early wet seasonmonth of Oc-