SHORT COMMUNICATIONS 429
WOLF, L. 1987. Host-parasite interactions of Brown- dation and parasitism on artificial nests and eggs headed Cowbirds and Dark-eyed Juncos in Vir- in two fragmented landscapes. Wilson Bull. 104: ginia. Wilson Bull. 99:338-350. 162-168. YAHNER, R. H. AND C. A. DELONG. 1992. Avian pre-
Wilson Bull., 110(3), 1998, pp. 429-430
First Record of Shiny Cowbird (Molothrus bonariensis) in YucatAn, Mexico
Daniel A. Kluza ’
ABSTRACT-Since the early 19OOs, the Shiny tentially confused, eye color and plumage dif- Cowbird (Molothrus bonariensis) has expanded its ferentiated it from Bronzed Cowbird (M. ae- range from northern South America through the West new), and the bill and tail shape separated it Indies. This spread has had detrimental effects on sev- eral species, especially endemics confined to islands. from Melodious Blackbird (Dives dives). The Here, I report the first record for Shiny Cowbirds in appearance of Shiny Cowbird in mangrove Mexico. The establishment of this species in the Yu- forest is not unexpected, as this seems to be catan Peninsula seems likely, and may pose a problem the preferred lowland habitat of the species in for the conservation of Yucatan endemics. Received 18 the Antilles (Post and Wiley 1977, Post et al. June 1997, accepted 5 March 1998. 1990). The spread of Shiny Cowbirds through the West Indies has been favored by the conver- The Shiny Cowbird (Molothrus bonarien- sion of forested areas to early successional sis) has rapidly expanded its range since the habitats, and by the absence of native brood turn of the century, island hopping from Trin- parasites (Post and Wiley 1977, Cruz et al. idad and Tobago north through the Lesser An- 1995). Contact with Shiny Cowbirds has prov- tilles, and west through the Greater Antilles en detrimental for some West Indian bird spe- (Post and Wiley 1977, Post et al. 1993). The cies, particularly the endangered Yellow- species was first recorded in Cuba in 1982 shouldered Blackbird (Agelaius xanthomus) (Garrido 1984) and in Florida in 1985 (Smith and the Puerto Rican Vireo (Vireo latimeri; and Sprunt 1987). From the Greater Antilles, e.g., Post and Wiley 1976, Post 1981, Wiley the Shiny Cowbird has been expected to in- et al. 199 1, Faaborg et al. 1997). Birds that vade into Florida and the Yucatan Peninsula have no evolutionary experience with brood of Mexico (Post and Wiley 1977, Howell and parasites may suffer high rates of parasitism Webb 1995). and reproductive failure (Wiley 1985, Post et On 27 May 1996, I observed a single male al. 1990, Cruz et al. 1995). Shiny Cowbird in an area of burned man- Eventual establishment of Shiny Cowbird groves adjacent to an intact mangrove forest populations in the Yucatan Peninsula seems at the eastern edge of the town of Rio Celes- likely, given that 25% of the regions’ forest tnn, Yucatan, Mexico. Identifying field marks has been converted to agriculture (Toledo and of the bird were a slender conical bill, uniform Orddfiez 1993). Yucatan birds may not be as dull blue-black plumage, squared-off tail, and vulnerable to brood parasitism as West Indian a solid dark eye. Of Yucatan resident species birds because of contact with the Bronzed with which the Shiny Cowbird could be po- Cowbird, which is resident throughout the Peninsula. However, experience with the ’ ’ Natural History Museum and Dept. of Systematics Bronzed Cowbird may be limited among Yu- and Ecology, Univ. of Kansas, Lawrence, KS 66045; catan birds because this species is less of a E-mail: [email protected]. generalist parasite, specializing mostly on ic- 430 THE WILSON BULLETIN l Vol. 110, No. 3, September 1998
terids and finches (Friedmann 1929, Oberhol- FAABORG, J., K. M. DUGGER, W. J. ARENDT, B. L. ser 1974). Thus, the presence of two sympat- WOODWORTH,AND M. E. BALTZ. 1997. Population declines of the Puerto Rican Vireo in Gu&nica ric brood parasites in the Yucatan may be det- Forest. Wilson Bull. 109: 195-202. rimental to more species. FRIEDMANN, H. 1929. The cowbirds: a study in the During the early years of Shiny Cowbird biology of social parasitism. Charles C. Thomas, range expansion (1920-1940), its primary Springfield, Illinois. hosts on Trinidad and Tobago included the FRIEDMANN, H. AND L. E KIFF. 1985. The parasitic House Wren (Troglodytes aedon) and Yellow- cowbirds and their hosts. Proc. West. Found. Ver- hooded Blackbird (Agelaius icterocephalus; tebr. Zool. 2:225-302. FRIEDMANN, H., L. E KIFF, AND S. I. ROTHSTEIN. 1977. Cruz et al. 1995). As the Shiny Cowbird has A further contribution to our knowledge of the moved through the Antilles, frequent host spe- host relations of the parasitic cowbirds. Smithson. cies included vireos, Dendroica warblers, Contrib. Zool. 235:1-75. Myiarchus flycatchers, as well as Agelaius GARRIDO, 0. H. 1984. Molothrus bonariensis (Aves: blackbirds (Wiley 1985, Post et al. 1990, Cruz Icteridae), nuevo record para Cuba. Misc. Zool. et al. 1995). 19:2-3. HOWELL, S. N. G. AND S. WEBB. 1995. A guide to the The ability of Yucatan endemics to persist birds of Mexico and northern Central America. in light of potential establishment of the Shiny Oxford Univ. Press, New York. Cowbird is an important question. Based on OBERHOLSER,H. L. 1974. The bird life of Texas. Univ. host choice trends of the Shiny Cowbird, Yu- of Texas Press, Austin. catan endemics at risk include the Yucatan POST, W. 1981. Biology of the Yellow-shouldered Flycatcher (Myiarchus yucatanensis), Yucatan Blackbird-Age&us on a tropical island. Bull. Fla. State Mus. Biol. Sci. 26:125-202. Wren (Campylorhynchus yucatanicus), Or- POST, W., A. CRUZ, AND D. B. MCNAIR. 1993. The ange Oriole (Zcterus auratus), Black Catbird North American invasion pattern of the Shiny (Melanoptila glabrirostris), Cozumel Vireo Cowbird. J. Field Omithol. 64:32-41. (Vireo bairdi), and Cozumel Wren (Troglo- POST, W., T. K. NAKAMURA, AND A. CRUZ. 1990. Pat- dytes beani; Friedmann 1929, Friedmann et al. terns of Shiny Cowbird parasitism in St. Lucia and 1977, Friedmann and Kiff 1985). Yucatan Vir- southwestern Puerto Rico. Condor 92:461-469. eo (Vireo magister) and White-browed Wren POST, W. and J. W. WILEY. 1976. The Yellow-shoul- dered Blackbird-present and future. Am. Birds (Thryothorus albinucha) are regional endem- 30: 13-20. its potentially also at risk of parasitism. Care- POST, W. and J. W. WILEY. 1977. The Shiny Cowbird ful monitoring of Shiny Cowbirds on the Pen- in the West Indies. Condor 79: 119-121. insula, and the effects on species already res- SMITH, W. P, AND A. SPRUNT, IV. 1987. The Shiny ident there, will be important. Cowbird reaches the United States. Am. Birds 41: 370-371. ACKNOWLEDGMENTS TOLEDO, V. M., AND M. ORD~REZ. 1993. The biodi- versity scenario of Mexico: a review of terrestrial C. S. Aid, A. T Peterson, and M. B. Robbins pro- habitats. Pp. 757-777 ilz Biological diversity of vided valuable comments on the manuscript. Travel to Mexico: origins and distribution (T P Rama- Mexico was made possible by a Tinker Field Research moorthy, R. Bye, A. Lot, and J. Fa, Eds.). Oxford Grant and a National Geographic Society grant to A. Univ. Press, New York. T. Peterson. WILEY, J. W. 1985. Shiny Cowbird parasitism in two avian communities in Puerto Rico. Condor 87: LITERATURE CITED 165-176. CRUZ, A., T. H. MANOLIS, AND R. W. ANDREWS. 1995. WILEY, J. W., W. POST, AND A. CRUZ. 1991. Conser- History of Shiny Cowbird Molothrus bonariensis vation of the Yellow-shouldered Blackbird, an en- brood parasitism in Trinidad and Tobago. Ibis 137: dangered West Indian species. Biol. Conserv. 55: 317-321. 119-138.