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Home/Species/ Bronzed Cowbird

Molothrus aeneus

(Wagler, 1829)

Bronzed Cowbird

G5Secure Found in 4 roadless areas NatureServe Explorer →
G5SecureGlobal Rank
Least concernIUCN
Identity
Unique IDELEMENT_GLOBAL.2.104495
Element CodeABPBXB7020
Record TypeSPECIES
ClassificationSpecies
Classification StatusStandard
Name CategoryVertebrate Animal
IUCNLeast concern
Endemicoccurs (regularly, as a native taxon) in multiple nations
KingdomAnimalia
PhylumCraniata
ClassAves
OrderPasseriformes
FamilyIcteridae
GenusMolothrus
Other Common Names
Tordo Ojo Rojo, Vaquero Ojirrojo, Pius (ES) Vacher bronzé (FR)
Concept Reference
American Ornithologists' Union (AOU). 1998. Check-list of North American birds. Seventh edition. American Ornithologists' Union, Washington, D.C. [as modified by subsequent supplements and corrections published in The Auk]. Also available online: http://www.aou.org/.
Taxonomic Comments
Composed of two groups formerly considered separate species: aeneus (Bronzed Cowbird) and armenti (Bronze-brown Cowbird, of South America) (AOU 1983, 1998). Often placed in genus Tangavius (AOU 1998).
Conservation Status
Review Date1996-12-04
Change Date1996-12-04
Rank Reasons
Widespread and common in agricultural areas.
Range Extent Comments
RESIDENT: from extreme southeastern California, western and central Arizona, southwestern New Mexico, western Chihuahua, and western and southern Texas south to Panama; locally uncommon to fairly common in coastal Caribbean Colombia in northern Magdalena (Ridgely and Tudor 1989). Northern populations partially migratory.
Ecology & Habitat

Habitat

Open country, ranches, roadside thickets, open woods, parks, orchards, pastures, around human habitation, open areas and fields with scattered bushes and low trees. BREEDING: Lays eggs in nests of other species; see Carter (1986) and Clotfelter and Brush (1995, Condor 97:814-815) for hosts in southern Texas, Stiles and Skutch (1989) for hosts in Costa Rica.

Ecology

Females pierce eggs of host and previously laid cowbird eggs (Carter 1986).

Reproduction

Lays eggs (usually 1 per nest) in nests of various bird species (Carter 1986, Stiles and Skutch 1989). Incubation 12-13 days, by host. Young leaves nest at about 11 days, fed by host for additional 2 weeks.
Terrestrial Habitats
Woodland - HardwoodShrubland/chaparralSavannaGrassland/herbaceousCropland/hedgerowSuburban/orchard
Palustrine Habitats
Riparian
Other Nations (1)
United StatesN4N,N5B
ProvinceRankNative
LouisianaS2BYes
CaliforniaSNRBYes
ArizonaS5Yes
New MexicoS4B,S4NYes
TexasS5BYes
Roadless Areas (4)
Arizona (4)
AreaForestAcres
ChiricahuaCoronado National Forest76,876
GoldfieldTonto National Forest15,257
Lime CreekTonto National Forest42,568
TumacacoriCoronado National Forest44,594
References (27)
  1. American Ornithologists' Union (AOU). 1983. Check-list of North American Birds, 6th edition. Allen Press, Inc., Lawrence, Kansas. 877 pp.
  2. American Ornithologists' Union (AOU). 1998. Check-list of North American birds. Seventh edition. American Ornithologists' Union, Washington, D.C. [as modified by subsequent supplements and corrections published in <i>The Auk</i>]. Also available online: http://www.aou.org/.
  3. Balda, R. P., and G. C. Bateman. 1971. Flocking and annual cycle of the piñon jay, <i>Gymnorhinus cyanocephalus</i>. Condor 73:287-302.
  4. Bent, A.C. 1958. Life histories of North American blackbirds, orioles, tanagers, and their allies. U.S. National Museum Bulletin 211. Washington, DC.
  5. BirdLife International. 2004b. Threatened birds of the world 2004. CD ROM. BirdLife International, Cambridge, UK.
  6. Carter, M. D. 1986. The parasitic behavior of the bronzed cowbird in south Texas. Condor 88:11-25.
  7. Friedmann, H. 1929. The cowbirds: a study in the biology of social parasitism. Charles C. Thomas, Publisher, Springfield, Illinois.
  8. Friedmann, H., and L.F. Kiff. 1985. The parasitic cowbirds and their hosts. Proc. Western Foundation of Vertebrate Zoology 2(4). 78 pp.
  9. Harrison, C. 1978. A Field Guide to the Nests, Eggs and Nestlings of North American Birds. Collins, Cleveland, Ohio.
  10. Harrison, H. H. 1979. A field guide to western birds' nests. Houghton Mifflin Company, Boston. 279 pp.
  11. Horn, H. S. 1968. The adaptive significance of colonial nesting in the Brewer's Blackbird. Ecology 49:682-694.
  12. Howell, S. N. G., and S. Webb. 1995. A guide to the birds of Mexico and northern Central America. Oxford University Press, Oxford, UK.
  13. Kostecke, R. M., K. Ellison, and S. G. Summers. 2004. Continued range expansion by bronzed cowbirds in the southwestern United States. Southwestern Naturalist 49:487-492.
  14. Ligon, J. D. 1971. Late summer-autumnal breeding of the piñon jay in New Mexico. Condor 73:147-153.
  15. Moore, W. S., and R. A. Dolbeer. 1989. The use of banding recovery data to estimate dispersal rates and gene flow in avian species: case studies in the Red-winged Blackbird and Common Grackle. Condor 91:242-253.
  16. Parker III, T. A., D. F. Stotz, and J. W. Fitzpatrick. 1996. Ecological and distributional databases for neotropical birds. The University of Chicago Press, Chicago.
  17. Poole, A. F. and F. B. Gill. 1992. The birds of North America. The American Ornithologists' Union, Washington, D.C. and The Academy of Natural Sciences, Philadelphia, PA.
  18. Ridgely, R. S. 2002. Distribution maps of South American birds. Unpublished.
  19. Ridgely, R. S. and G. Tudor. 1989. The birds of South America. Volume 1. University of Texas Press, Austin, USA. 516 pp.
  20. Ridgely, R. S. and J. A. Gwynne, Jr. 1989. A Guide to the Birds of Panama. 2nd edition. Princeton University Press, Princeton, USA.
  21. Stiles, F. G. and A. F. Skutch. 1989. A guide to the birds of Costa Rica. Cornell University Press, Ithaca, New York, USA. 511 pp.
  22. Tarvin, K. A., and G. E. Woolfenden. 1999. Blue Jay (<i>Cyanocitta cristata</i>). No. 469 IN A. Poole and F. Gill, editors. The birds of North America. The Birds of North America, Inc., Philadelphia, PA. 32pp.
  23. Terres, J. K. 1980. The Audubon Society encyclopedia of North American birds. Alfred A. Knopf, New York.
  24. Thompson, F. R., III. 1994. Temporal and spatial patterns of breeding brown-headed cowbirds in the midwestern United States. Auk 111:979-990.
  25. Williams, L. 1952b. Breeding behavior of the Brewer blackbird. Condor 54:3-47.
  26. Willson, M. F. 1966. Breeding ecology of the Yellow-headed Blackbird. Ecological Monographs 36:51-77.
  27. Zook, J. L. 2002. Distribution maps of the birds of Nicaragua, Costa Rica, and Panama. Unpublished.