Shiny Cowbird
Shiny Cowbird
Molothrus bonariensis
At a Glance
Originally native to South America, this little blackbird spread gradually through the West Indies in recent decades, island-hopping north through the Lesser Antilles and then west toward Cuba. The Shiny Cowbird arrived in Florida in 1985, and has become locally common there, with some seen elsewhere in the Southeast. Like other cowbirds, this species is a nest parasite, so its arrival in our area was not welcomed by conservationists.
All bird guide text and rangemaps adapted from Lives of North American Birds by Kenn Kaufman© 1996, used by permission of Houghton Mifflin Harcourt Publishing Company. All rights reserved.
Category
Blackbirds and Orioles, Perching Birds
IUCN Status
Least Concern
Habitat
Coasts and Shorelines, Fields, Meadows, and Grasslands, Shrublands, Savannas, and Thickets, Urban and Suburban Habitats
Region
Florida
Behavior
Direct Flight, Flitter
Range & Identification
Migration & Range Maps
Pattern of migration within North America still poorly known. In some recent years, numbers have been seen moving through southern Florida in spring, suggesting flocks arriving from Caribbean. Strays have dispersed as far as Texas, Oklahoma, and Maine.
Description
Sexes similar — Length: 7-8 in (18-20 cm); wingspan: 12-13 in (30-33 cm); weight: 1.4-1.8 oz (40-50 g). A Shiny Cowbird is much like a Brown-headed Cowbird in size and shape (females not safely identified), but male is black all over, with shiny purple gloss. Most other all-black birds are either much larger or have pale eyes.
Size
About the size of a Robin, About the size of a Sparrow
Color
Black, Brown, Gray, Purple
Wing Shape
Rounded
Tail Shape
Notched, Rounded, Square-tipped
Songs and Calls
Song is a melodious warble. A variety of harsh metallic call notes.
Call Pattern
Flat, Rising
Call Type
Buzz, Chatter, Chirp/Chip, Hi, Rattle, Whistle
Habitat
Semi-open country. In North America, has been found mostly near the coast, often foraging on extensive lawns. In the tropics, found in any kind of open or semi-open terrain, mostly in the lowlands.
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Behavior
Eggs
The eggs are quite variable in color: may be unmarked white, or may have gray dots, large red spots, dark lines, brown blotches, or rarely can be all dark red. Number of eggs laid by a female in one season is unknown, but may be many. The female Shiny Cowbird sometimes punctures the eggs already in a nest before she lays her own. In South America, parasitizes nests of many species. May specialize in other areas: in Puerto Rico, mostly parasitizes Yellow-shouldered Blackbird.
Young
The Shiny Cowbird nestling is fed by "host" parents and develops rapidly, probably leaving nest after about 10-12 days.
Feeding Behavior
Forages mostly by walking on the ground in open areas. Often forages in small flocks, and may associate with other kinds of cowbirds or other blackbirds. In the tropics, will feed in association with horses or cattle in pastures.
Diet
The diet of a Shiny Cowbird in North America has not been studied. In the tropics, feeds on insects and other arthropods, and many seeds.
Nesting
A brood parasite, never raising its own young. Early in breeding season, males sing to attract females. A male singing to a female on the ground may take off and fly in a wide circle around her with fluttering wingbeats. Nest: Builds no nest of its own; lays its eggs in nests of other birds.
Conservation
Conservation Status
Overall, Shiny Cowbird numbers appear to be on the rise through much of their range. Impact of this parasite on North American birds remains to be seen. In Puerto Rico, has driven Yellow-shouldered Blackbird to endangered status.
