Family New World Blackbirds (Icteridae)

Least Concern

Bronzed Cowbird (Molothrus aeneus)


French: Vacher bronzé German: Rotaugen-Kuhstärling Spanish: Tordo ojirrojo

P[sarocolius]. aeneus


, 1829,

Veracruz, Mexico


Formerly placed in genus Tangavius, but such treatment not supported by molecular work. Often considered conspecific with M. armenti (which see). Three subspecies recognized.

Subspecies and Distribution
  • M. a. loyei Parkes & Blake, 1965 – SW USA (S California, Arizona, New Mexico and W Texas) S in W Mexico to Nayarit and N Baja California.
  • M. a. aeneus (Wagler, 1829) – S USA (E New Mexico, S Texas, Louisiana and Florida) and from E & C Mexico S, including nearby islands (e.g. Cozumel I), to C Panama.
  • M. a. assimilis (Nelson, 1900) – SW Mexico from Jalisco S to Chiapas.
  • Descriptive notes

    Male 20 cm, average 68·9 g; female 18 cm, average 56·9 g. Male nominate race is mostly black with bronze gloss, including erectile neck ruff, but iridescence on... read more


    Male song a crescendo that includes short introductory notes followed by longer high-pitched... read more


    Open country in areas with xeric to humid vegetation, usually avoiding dense forest or woodland.... read more

    Food and feeding

    Mostly seeds and arthropods. Stomach contents of fully adult males more than 90% seeds (including of cultivated Sorghum vulgare),... read more


    Season Apr–Jul. Apparently polygynous or promiscuous. Male displays expanded ruff while singing from perch; sings also during “... read more


    Populations in most of USA range (California, Arizona, New Mexico, Texas and Louisiana) and in CN... read more

    Status and conservation

    Not globally threatened. Common to fairly common in most of range, less common in interior Mexico; less numerous than M. ater. Somewhat more local in non-breeding... read more

    Recommended citation

    Fraga, R. (2019). Bronzed Cowbird (Molothrus aeneus). In: del Hoyo, J., Elliott, A., Sargatal, J., Christie, D.A. & de Juana, E. (eds.). Handbook of the Birds of the World Alive. Lynx Edicions, Barcelona. (retrieved from on 11 December 2019).