The shiny cowbird is a passerine bird in the New World family Icteridae. It breeds in most of South America except for dense forests and areas of high altitude such as mountains. Since 1900 the shiny cowbird's range has shifted northward, and it was recorded in the Caribbean islands as well as the United States, where it is found breeding in southern Florida. It is a bird associated with open habitats, including disturbed land from agriculture and deforestation.
Region
South America and Caribbean
Typical Environment
Found across most of South America except dense interior rainforests and very high elevations. It occupies open and semi-open habitats such as pastures, agricultural fields, savannas, mangrove edges, coastal scrub, and urban parks. In the 20th century it spread through many Caribbean islands and reached Panama, Costa Rica, and southern Florida, where it now breeds locally. It often follows human-altered landscapes and associates with livestock and disturbed ground.
Altitude Range
Sea level to 2400 m
Climate Zone
Tropical
Ease of Keeping
Beginner friendly: 1/5
A widespread brood parasite, the shiny cowbird lays its eggs in the nests of other birds—over 200 host species are recorded. Its range has expanded northward through the Caribbean and into southern Florida, aided by deforestation and agriculture that create open habitats. This expansion has negatively impacted some small island endemics that are vulnerable to parasitism.
Female shiny cowbird
Grouping of males
Molothrus bonariensis in a clutch of Curaeus curaeus - MHNT
A juvenile (left) being fed by a rufous-collared sparrow (right)
Temperament
social and active
Flight Pattern
short rapid wingbeats
Social Behavior
Often occurs in flocks, frequently mixing with other icterids and foraging near livestock. It is an obligate brood parasite, laying eggs in the nests of many host species and providing no parental care. Courtship includes male displays and chasing; communal roosts form outside the breeding season.
Migratory Pattern
Partial migrant
Song Description
Song consists of high, thin whistles and liquid gurgling phrases, often delivered from exposed perches. Calls include sharp chips and metallic squeaks, repeated in short series during social interactions.
Plumage
Male is uniformly glossy with a purplish-black sheen; female is plain brown to gray-brown with paler underparts and faint streaking. Both sexes have a neat, smooth appearance without wing bars.
Diet
Feeds on grass and weed seeds, grains, and a wide variety of insects and other arthropods, especially those flushed by livestock or human activity. It will also take small fruits and occasionally scavenge at food scraps. Foraging is mainly on the ground with short hops and quick pecks.
Preferred Environment
Typically feeds in open fields, grazed pastures, road edges, crop stubble, and park lawns. Frequently accompanies cattle and tractors that disturb insects, and also visits coastal flats and mangrove margins.
