BREEDING RECORD The ShinyCowbird reaches the UnitedStates Will the scourge of the Caribbean impact Florida's avifauna too?

P. William Smith and Alexander Sprunt IV

ductinga BreedingBird Surveyon NLowerJUNE Matecumbe14,1985, Key,WHILE MonroeCON- County, Florida, Sprunt and Karen Sunderland discoveredthe first Shiny Cowbird (Molothrus bonariensis) re- ported in the United States,a male, with Red-winged Blackbirds (Agelaius phoeniceus) in mangroves near the shoulderof the OverseasHighway (U.S. 1). Its appearancein Florida was hardly unexpected. From its South American base, the Shiny Cowbird has spread northward, mostly during this century, through the Antilles; its expansionhas been particularly strongover the last 30 years(Post and Wiley 1977; Arendt and Figure 1. Three male Shiny Cowbirdsjoin Mourning Dovesand Eura•ian Collared-Dovesat Vargas 1984). By 1982, the specieshad Islamorada.Florida. July 5, 1986. Photo/P William Smith (VIREO SI4/2/003). reachedthe north coastof Cuba (Bond in the United States. This constituted On the other hand, female and ju- 1984;Cruz el al. 1985), only about 100 the first recordfor the Florida peninsula venile Shiny Cowbirds representa def- miles south of its point of discoveryin and the first definite report of a female inite identification challenge (Figs. 5- the United States. After it was relocated in the United States. Up to five male 6). An examination of specimensat the at a nearby feeder, the Lower Matec- and two female Shinies were seen to- Academy of Natural Sciences,in Phil- umbe Shiny Cowbird was observedby getherwith the Brown-headedCowbirds adelphia, reveals that except for head birders for several weeks. at Flamingo until at least late June and bill shape,there is almost complete In 1986, Smith and his wife were 1987.A juvenileShiny was present from overlap in charactersbetween female trying to capture Eurasian Collared- June 27 until late July, suggestingthe Shinies of the race minimus. the one Doves(Streptopelia decaocto) at nearby possibilitythat breedingin Florida has Islamorada as part of a field project already begun. when, on July 5, three male Shiny Cow- Identifying adult male Shiny Cow- birds landed besidetheir dove trap. Too birds is easy.The> are similar in sizeto surprisedto focusproperly, Smith cap- Brown-headed Cowbirds but have a tured the birds quickly on film (Fig. 1). sleekerlook, causedby a thinner profile, One or more of these birds was seen longertail, flatterhead, and a longer,less subsequentlyin the vicinity by other conicalbill (Figs.2-4). The head,breast, observers, but apparently no better and upper back are entirely glossypur- documentation of this speciesat lsla- ple, becomingduller on the lower back, morada in 1986 was obtained. wingsand tail. and fading on the belly On May 25, 1987, Smith and hiswife (Figs. 2-3). The brownisheyes do not followedup rumorsof a ShinyCowbird standout againstthe face(Fig. 2). in EvergladesNational Park to find a All other glossy purple speciesof male and femaleassociating with several blackbirds,such as grackles(Quiscalus Brown-headed Cowbirds (Molothrus sp.), are larger.Most similar species,like ater) on the lawn in front of the Fla- the greenerand lessiridescent Brewer's mingo Visitors' Center. The visitors' Blackbird (Euphaguso'anocephahts), observationlog showed that a Shiny also have light eyes.The BronzedCow- Cowbird had been reported there to a bird (Molothrusaeneus), which hasbeen Figure 2. Male Shiny Cowbirdwith a Brown- park ranger on May 5, by an unidenti- seenin southFlorida in winter, is larger. headedCou'bird at Flamingo. Florida. Ma_v fied observer.These birds were easily hasan obviousred eyeand ruffled neck, 25. ! 987. Note Shiny'spurple body gloss and photographed(Figs. 2-5), proving be- and showsbronzy rather than purple longer.thinner bill. Photo/P H •11iamSmith yond doubt the presenceof this species body iridescence. ([ ?REO S14/3/000.

370 American Birds, Fall 1987 spreadingShiny Cowbird's brood par- asitismon Caribbean speciessuch as the Yellow-shoulderedBlackbird (Agelaius xanthomus)have expressed concern for the region'sunadapted avifauna (Post and Wiley 1976; Cruz et al. 1985). The ShinyCowbird's arrival in southFlorida maywell posesimilar problems for some local species (Paul 1985). However, Brown-headed Cowbirds, equally new to south Florida during the breeding season, probably pose at least as great a threat. Thus, it seems inappropriate

Figure3. Note Shiny Cowbird'scolor, size, shape, and tail lengthcompared to Brown-headed Cowbird.Flamingo, Florida, May 25, 1987. Photo/P. William Smith (VIREO SI4/3/002).

Figure 5. lVoteJemale Shmy'sfiatter head, longer, thinner bill. more prominent eye stripe, and slightly darker colorationcom- pared to female Brown-headed Cowbird. Flamingo, Florida, May 25, 1987. Photo/P I•¾11iamSmith (I'IREO S14/3/004).

to singleout the Shiny Cowbird as an undesirable addition to the region's birdlife. We thank Kenn Kaufmann for assis- tance at the Academy of Natural Sci- Figure 4. Female Shiny Cowbirdhas similar bill shapeto male's. Flamingo, Florida, May ences and Karen Sunderland and Susan 25, 1987. Photo/P. William Smith (VIREO S14/3/003). A. Smith for help in the field.

LITERATURE CITED

ARENDT, W. J. and T. A. VARGAS MORA. 1984. Range Expansion of the Shiny Cowbird in the Dominican Re- public. J. Field Ornithol. 55:104-107. BOND, J. 1984. Twenty-fifth Supplementto the Checklist of the Birds of the West In- dies (1956). Academy of Natural Sci- ences,Philadelphia. p. 14. CRUZ, A., T MANOLIS, and J. W. WILEY. 1985. The Shiny Cowbird: A Brood Par- asite Expanding its Range in the Carib- bean Region. Ornithol. Monogr. 36:607- 620. PAUL, R. T 1985. Florida Region [Summer Figure6. FemaleShiny Cowbird (above) may be virtuallyidentical to female Brown-headed 1985]. Am. Birds 39:902-905. exceptfor head and bill shape.Specimens courtesy of the Academyof Natural Sciences,Phil- POST, W. and J. W. RILEY. 1976. The Yel- adelphia.PA. Photo/P. William Smith. low-shouldered Blackbird--Present and Future. Am. Birds 30:13-20. __. 1977. The Shiny Cowbird in the West spreadingnorth to the United States, in the field--to our knowledge,the two Indies. Condor 79:119-121. and correspondingly aged Brown- specieshave never before occurred to- headedCowbirds (Fig. 6). The female- gether.It follows that until more expe- -South Florida Research Center, type Shiny appears a bit darker and rience is gained, female-typecowbirds EvergladesNational Park, P.O. Box showsa somewhatmore prominent eye- in south Florida should be identified 279, Homestead,FL 33030 (Smith); stripe than the female-type Brown- with great care and usually referredto ResearchDept., National Audubon headed (Fig. 5), but the reliabihty of as cowbird, sp. Society,115 Indian Mound Trail, thesedifferences has not yet beentested Biologistsstudying the impact of the Tavernier,FL 33070 (Sprunt).

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