Molothrus bonariensis
The Shiny Cowbird, Molothrus bonariensis, is a small, glossy black passerine renowned as an obligate brood parasite, placing its eggs in the nests of over 200 other bird species. Males are distinguished by their iridescent blue-black plumage, which shimmers with purple and green hues in good light, measuring around 18-20 cm in length and weighing 40-50 grams. Females are a drabber, uniform sooty brown, slightly smaller and less iridescent, providing a clear example of sexual dimorphism. These...
Found primarily in open, disturbed habitats such as grasslands, agricultural fields, pastures, suburban parks, and urban areas, often near livestock. It occupies elevations from sea level up to approximately 3,000 meters in parts of its South American range.
Primarily omnivorous, feeding on a wide variety of arthropods, including insects and spiders, often gleaned from the ground. They also consume significant amounts of seeds from grasses and agricultural crops, occasionally taking small fruits.
Shiny Cowbirds are highly social birds, often foraging in mixed-species flocks with other icterids and starlings, particularly outside the breeding season. They are diurnal, spending much of the day foraging on the ground or among vegetation, and typically gather in large communal roosts at night...
The native range of the Shiny Cowbird encompasses a vast area of South America, from Colombia, Venezuela, and the Guianas south through Brazil, Bolivia, Paraguay, Uruguay, and Argentina to Tierra del Fuego. It is also found across many Caribbean islands, including Cuba, Hispaniola, Puerto Rico, a...
Least Concern
- Shiny Cowbirds are obligate brood parasites, meaning they *never* build their own nests or raise their young. - They have been documented to parasitize over 200 different species of host birds, an astonishing number among brood parasites. - Females can lay up to 40-50 eggs in a single breeding ...