- 7.9 in
- 13 in
- 1.9–2.5 oz
- Red-eyed Cowbird
- Vacher bronze (French)
- Tordo ojirojo (Spanish)
- Nest success for brood parasites (birds that lay eggs in the nests of other bird species) usually is best when only one parasite egg is laid in a given nest. Host nests frequently contain multiple Bronzed Cowbird eggs. Some female cowbirds peck the other cowbird eggs before laying their own eggs, effectively reducing the number of cowbird eggs in the nest.
- The maximum number of Bronzed Cowbird eggs found in one nest was 14 in an abandoned nest.
Open fields, pastures, scrubby areas, tropical semideciduous forest, tropical deciduous forest, tropical scrub, lawns, golf courses, and agricultural areas.
Seeds and arthropods.
- Egg Description
- Unmarked bluish green.
- Condition at Hatching
- Helpless with sparse gray down.
None. Lays eggs in nests of other bird species.
Forages as it walks on ground; rarely in vegetation, frequently in association with cattle; forages in flocks, often with other blackbirds.
Settlement of North America by Europeans has undoubtedly permitted expansion by Bronzed Cowbird into areas converted into agricultural habitats. Management concerns are more likely for host species than for the cowbird. Bronzed Cowbird parasitism has been assumed to be a factor (along with habitat loss) responsible for decreasing populations of Altamira Orioles and Audubon's Orioles in southern Texas.
- Lowther, P. E. 1995. Bronzed Cowbird (Molothrus aeneus). In The Birds of North America, No. 144 (A. Poole and F. Gill, eds.). The Academy of Natural Sciences, Philadelphia, and The American Ornithologistsâ€™ Union, Washington, D.C.