1088 SHORT COMMUNICATIONS

tion. I. Temperate habitats. Behav. Ecol. Socio- dialectsand their possiblerelation to honest status biol. 2:27 l-290. sianalline in the Brown-headed Cowbird. Condor tirrs~, K., QUINE,D., ANDP. w. 1977. Sound 8g l-23.- transmission and its significancefor animal com- RYAN, M. J., AND E. A. BRENOWITZ. 1985. The role munication. II. Tropical forest habitats. Behav. of body size, phylogeny,and ambient noise in the Ecol. Sociobiol. 2:27 l-290. evolution of song. Am. Nat. 126:87-100. MORTON, E. S. 1975. Ecologicalsources of selection SHY, E. 1983. The relation of geographicalvariation on avian sounds.Am. Nat. 109:17-34. in songto habitat characteristicsand body size in MUNDINGER, P. C. 1982. Microgeographicand mac- North American Tanagers(Thraupinae: Piranga). rogeographicvariation in acquired vocalizations Behav. Ecol. Sociobiol. 12:7l-76. of , p. 147-208. In D. E. Kroodsma and E. TUBARO.P. L.. SEGURA. E. T., AND P. HANDFORD. H. Miller [eds.],Acoustic communication in birds, 1993. Geographic variation in the song of the Vol. 2. Academic Press, New York. Rufous-collaredSparrow (Zonotrichia capensis) in Norrano~~, F. 1969. The songof the chingolo, Zo- eastern Areentina. Condor 95:588-595. notrichia capensis, in Argentina: description and WAAS, J. R. 1988. Song pitch-habitat relationships evaluation of a systemof dialects.Condor 7 1:299- in White-throated Sparrow: cracksin the acoustic 315. windows? Can. J. Zool. 66:2578-2581. Nor-rnacm~, F. 1975. Continental patterns of song WASS~RPAAN,F. E. 1979. The relationship between variability in Zonotrichia capensis: some possible habitat and song in the White-throated Sparrow. ecologicalcorrelates. Am. Nat. 109:605424. Condor 8 1:424-426. NO~~ELIOHM,F. 1985. Sound transmission,signal sa- WILEY, R. H. 1991. Associationsof song properties lience and songdialects. Behav. Brain Sci. 8: 112- with habitats for territorial oscinebirds of eastern 113. North America. Am. Nat. 138:973-993. RICXURDS, D. G., AND H. WILEY. 1980. Reverbera- WILEY, H., AND D. G. RICHARDS. 1978. Physicalcon- tions and amplitude fluctuations in the propaga- straints on acousticcommunication in the atmo- tion of sound in a forest: implications for animal sphere. Implications for the evolution of . Am. Nat. 115:38l-393. vocalizations. Behav. Ecol. Sociobiol. 3:69-94. Rorrrsrar~, S. I., AND R. C. FLFBCHER. 1987. Vocal

The Condor96:1088-1091 Q The CooperChnithologid Society 1994

AERIAL SOUNDS OF THE BLACK-CHINNED ’

CAROLYN Fr1-r19 AND MILLICENT SIGLER FICKEN Department of Biological Sciences, University of Wisconsin-Milwaukee, Milwaukee, WZ 53201

Key words: ; ; displays; vo- Aerial displays of many hummingbirds consist of calizations; Trochilidae. repeatedpendulum-like arcsor vertical oval flightsper- formed by both sexesin some speciesand usedin both Remarkably little is known of the soundsproduced by territorial and courtship displays (Pitelka 1942, Banks hummingbirds. Earlier work is descriptive, and there and Johnson 1961, Stiles 1982). Soundsare generally are few published sonograms(see Mirsky 1976, Wells producedat the baseofthe arc, directly above the other et al. 1978, Baptista and Matsui 1979, Wells and Bap- bird (See descriptionsin Bent 1940). tista 1979). Considerable debate concerns whether Here we presenta sonographicanalysis of the sounds soundsproduced during aerial displays are vocal, me- produced during aerial displays by the Black-chinned chanical or both (Rodgers 1940, Wells et al. 1978, Hummingbird (Archilochus alexandrz]. We compare Baptista and Matsui 1979). The sourcesof dive sounds sonogramsof aerial display sounds to sonogramsof cannot be determined by ear, and visual inspection of mechanical and vocal sounds produced by Black- sonograms can be inconclusive. In some cases, the chinned Hummingbirds in other contexts.In addition, structureand temporal pattern of the soundscould fit we compare Black-chinned Hummingbird display either categoryof sound production. soundsto publishedaccounts oftbe aerialdisplay sounds of the Anna’s Hummingbird (Culypte anna) and Cos- ta’s Hummingbird (Cahpte costae), which are closely related to the Black-chinnedHummingbird (Mavr and I Received 7 February 1994. Accepted 18 July 1994. Short 1970). Based on these analyses,we suggestthe * Present address: Department of Biology, Indiana vocal source of the dive soundsof the Black-chinned University, Bloomington, IN 47405. Hummingbird. SHORT COMMUNICATIONS 1089

8-

7-

0 I I I 0.5 1 1.5 Time (s)

FIGURE1. Aerial display soundsof a male Black-chinned Hummingbird showing X and Y elements.

METHODS bout consisted of six dives, the second of nine. The Displays were observed at approximately 17:00 CST female remained silent throughout the observations. in Ramsey Canyon, Arizona, on 21 May 1993. The DISCUSSION displays occurred in sparsely vegetated pine-oak-ju- niper habitat at about 2,000 m. The microphone was The trill (X) component of the aerial display is struc- held approximately 3 m from the female target of the turally similar to wing noises of male Black-chinned display. The male was between l-5 m from the female Hummingbirds producedin agonisticinteractions (Figs. when producing the display sounds.Recordings were 1,2). Both are composedof a rapid trill. Some notable made with a Sony Walkman Professionalcassette re- differencesalso occur. The temporal pattern of the X corder (WM-D6C) and Audio-technica line cardioid trill is unlike wing noise producedin all other recorded microphone (AT877). Sonogramswere produced on a contextsincluding hovering, turning, and direct flights. Ray Sona-graph 7800 (150 Hz band width). The duration is shorterand X elementsdo not continue throughout the course of the dive or through the full base of the arc, but only in conjunction with the Y RESULTS components which are produced immediately above The aerial display dives of the Black-chinned Hum- the target of the display. Presumably, if the X com- mingbird are U-shaped pendulum flights (Bent 1940). ponent were a byproduct of the flight movements, the The arms of the U are not vertical, but lie at about a sound would increase in amplitude as the bird flew 45” angle from the horizon. The apex of each upward towards the mircophone, and fade as he flew away. flight is approximately 20-30 m from the ground. In Instead, there is a relatively abrupt appearance and the aerial displays observed in this study, the base of disappearanceof the sound as the bird is directly over the U was about 1 m above a bush in which a female the female. While we do not dismiss the possibility Black-chinned Hummingbird was perched approxi- that hummingbirds are capable of controlling the tim- mately 1.5 m from the ground. While flying directly ing of wing noises used in communication, the tem- above the female, the male produceda seriesof sounds poral characteristicsof the component in conjunction in rapid succession.There was no apparent change in with the Y elements are more supportive of the hy- flight speedduring any part of the display except when pothesis that the sound is not a function of the flight the male reachedthe top of the arc and turned around movements as it is in Broad-tailed Hummingbirds to fly down again. The male did not appear to point (Selaspho~p~~tycercu (Miller and Inouye 1983). In its bill down towards the female while flying upward addition, the frequency range of X elements does not along the arms of the arc as does the displayingAnna ’s overlap that of wing noises. The frequency of the X Hummingbird (review in Wells et al. 1978). elements is between 4-5 kHz and wing noisesare pro- Two display boutswere separatedby a 4 min interval duced at 2-3 kHz (Figs. 1, 2). during which the male was not in sight.The first display The Y elements are short, pure tone “bell-like” 1090 SHORT COMMUNICATIONS

0.5 1 Time (s) FIGURE 2. Wing buzz of a male Black-chinned Hummingbird during an agonisticinteraction.

sounds. These elements are structurally unlike either sounds would be very different from agonistic ones. mechanicalor vocal soundsrecorded in other contexts. Additional characteristicssuggest vocal origins. Like The Y element is dissimilar to vocal soundsproduced the X elements, the frequency range of Y elements is in agonisticinteractions, but agonisticvocalizations are within that of vocally produced notes. The inter-note variable, and it is not surprising that aerial display interval between Y elements and between X elements is also similar to that found between notes in vocally produced sequences(Fig. 3). No similar temporal pat- 8 terns have been found in wing noises. Instead, wing soundsare long segmentsof continuous“buzzing.” We also believe the hypothesisthat the X element is me- chanical and Y element vocal can be rejected because of the improbability of two different soundproduction x? 6- mechanisms showing such precise alternation within these time intervals (Fig. 1). Probably the most convincing evidence for vocal 5 5- origins of the Black-chinned Hummingbird display sounds is revealed by comparisons of these display sounds with the aerial display sounds of the Anna’s 6f 4- Hummingbird. The X note ofthe Black-chinnedHum- mingbird is structurallysimilar to the vocally produced s 3- “a” elements of the Anna’s Hummingbird. The “a” elements are producedby Anna’s Hummingbirds dur- 2 ing aerial courtship displays and during singing while IL 2- perched (Baptista and Matsui 1979. Fin. 1). Elements \I\ similar to X-and Y are also shown in &me sonograms of the Anna’s Hummingbird by Mirsky (1976). Simi- larly, the Costa’s Hummingbird producesa vocal note during its aerial courtship display which is also pro- duced during perched singing (Wells et al. 1978). As these sounds were produced while the birds were 0.5 perched, wing noise can be ruled out as a source. Cu- Time (s) lypteand Archilochusare closelyrelated and have been known to hybridize (Mayr and Short 1970). Evolu- FIGURE 3. Vocally producednote sequenceof a male tionary conservatism would support the notion that Black-chinned Hummingbird during an agonistic in- similarity ofnote structuresuggests a similarity in means teraction. of production. SHORT COMMUNICATIONS 1091

We thank the staff of the Ramsey Canyon Preserve Broad-tailed Hummingbirds (Selasphor~~platy- of the Nature Conservancy. Jevra Brown provided cercus).Anim. Behav. 3 1:689-700. valuable assistancein the field. Luis Baptista offered MIRSKY,E. N. 1976. Song divergence in humming- helpful comments on the manuscript. bird and junco populations of Guadalupe Island. Condor 78:23&235. LITERATURE CITED P~TELKA,F. A. 1942. Territoriality and related prob- BANKS,R. C., AND N. K. JOHNSON.1961. A review lems in North American hummingbirds. Condor of North American hybrid hummingbirds. Con- 63:3-28. dor 63:3-28. RODGERS,T. L. 1940. The dive note of the Anna’s BAPTISTA,L. F., AND M. MAIWI. 1979. The source Hummingbird. Condor 42:86. of the dive-noise of the Anna’s Hummingbird. Sn~ns, F. G. 1982. Aggressiveand courtshipdisplays Condor 81:87-89. of the male Anna’s Hummingbird. Condor 84: BENT,A, D. 1940. Life histories of North American 208-225. cuckoos,goatsuckers, hummingbirds and their al- WELIS, S., AND L. F. BAYIXTA. 1979. Displays and lies. U.S. Natl. Mus. Bull. 176. morphology of an Anna x Allen Hummingbird MAYR, E., AND L. L. SHORT. 1970. Speciestaxa of hybrid. Wilson Bull. 91(4):524-532. North American birds. Publ. Nuttal Omithol. Club WELLS,S., R. A. BRADLEY,AND L. F. BAPTISTA.1978. no. 9. Hybridization in CaIyptehummingbirds. Auk 95: MILLER,S. J., ANDD. W. INOUYE. 1983. Roles of the 537-549. wing whistle in the territorial behaviour of male

The Condor96:1091-1094 0 The Cooperomithological society 1994

THE NONBREEDING DISTRIBUTION OF THE BLACK SWIFT: A CLUE FROM COLOMBIA AND UNSOLVED PROBLEMS’

F. GARY STILES Instituto de CienciasNaturales, UniversidadNational de Colombia,Apartado 7495, Bogoth,Colombia ALVAROJ. NEGRIZT Muse0 de Historia Natural, Universidadde1 Cauca, Popaybn,Colombia

Key words: Black Swift; Cypseloidesniger; Colom- America from extreme southeasternAlaska to Vera- bia; distribution;migration. cruz, Mexico (Friedmann et al. 1950, AOU 1957). The winter range of this race was long consideredto lie in The distributionsof many speciesof swifts of the genus southern Mexico (e.g., AOU 1931), but a thorough Cypseloidesremain poorly known, due to the difficul- examination of existing specimen records led Bent ties of field identification and collecting specimensof (1940) to conclude that no authentic winter records theseobscurely marked, usuallyhigh-flying birds. New existed, all birds from southern Mexico having been specimenreports and breedingrecords (e.g., Marin and taken during breeding or migration periods. Positive Stiles 1992, 1993) often involve large rangeextensions information on this point has remained elusive;yet the or overturn previous ideas regarding breeding areas AOU (1983, p. 3 17) still stated “winters in Mexico and seasonalmovements (see Marin and Stiles 1992 (presumably).” However, they overlookeda significant vs. Monroe 1968 on C. cryptusfor one suchexample). specimen record for the. spring migration pe&d (19 In this report we describethe first recordsof the north- A~til) from southwesternCosta Rica (Kiff 1975). Stiles em Black Swift (C. niger borealis)for Colombia, in- and Skutch (1989) reported regularly seeing flocks of deed, for SouthAmerica, and we review and reinterpret up to 30 Black Swifts over the Valle Central of Costa existing information for this and other races of the Rica during April to early May and Septemberto early species. If this analysis seems to further confuse an October in various years (inclusive dates 9 April-l 1 already cloudy situation, it also serves to emphasize May, 13 September-l 0 October). Although specimens our all too fragmentary knowledge regardingthis spe- were not obtained, it is possible that these birds were cies. migrating borealis.These reports suggestthat this race The breeding range of C. n. borealis includes the might winter much further south than previously sup- mountainous areas of western North and Central posed.Reports of Black Swifts at seaoff Chiapasduring the spring migration period (16 May 1963, Buchanan and Fierstine 1964), and off Guatemala during fall mi- I Received 14 February 1994. Accepted 1 June 1994. gration (20 September 1933, Davidson 1934) are also