Family New World Blackbirds (Icteridae)

Least Concern

Screaming Cowbird (Molothrus rufoaxillaris)


French: Vacher criard German: Rotachsel-Kuhstärling Spanish: Tordo chillón

Molothrus rufo-axillaris


, 1866,

Buenos Aires, Argentina




SE Bolivia and C Brazil (S from Mato Grosso, Goiás and W Minas Gerais, expanding to S Tocantins#R and C & N Minas Gerais#R), S throughout Paraguay and Uruguay to NE & C Argentina (S to Río Negro and NE Chubut); breeding recently recorded in C Chile#R.

Descriptive notes

Male 20·3 cm, average 58 g; female 19·2 cm, average 48·8 g. Male is entirely black with bluish iridescence (ultraviolet reflectance slight), except for rufescent lesser... read more


Rather noisy, commonly vocalizing throughout year. Song, by perched male, a brief, piercing and... read more


Original habitat probably grassland near woodland edge, and open woodlands of many types,... read more

Food and feeding

Insects and other arthropods, and seeds. Insects in stomach contents include beetles (of families Chrysomelidae and Scarabaeidae) and ants... read more


Season Oct–Mar in C Argentina. Apparently monogamous; male accompanies female constantly, pair-bond lasts a minimum of one or two... read more


Apparently sedentary.

Status and conservation

Not globally threatened (Least Concern). Locally uncommon to common. Has more than doubled the extent of its range in the last 50 years, probably assisted by conversion of... read more

Recommended citation

Fraga, R. & Garcia, E.F.J. (2020). Screaming Cowbird (Molothrus rufoaxillaris). 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 25 February 2020).