The Brown-headed Cowbird feeds on the ground in open habitats. Females do not build their own nests; they lay eggs in the nests of other birds.
Males have glossy black bodies and brown heads, while females are mostly pale brown. Both have a short, thick bill.
Brown-headed cowbirds lay eggs in the nests of other birds and leave the host parents to raise their young. In Alberta’s mixed-grass prairie, researchers compared cowbirds and Savannah Sparrow nests at sites with oil and gas infrastructure and at control sites during 2013–2014.
Cowbird relative abundance was about four times higher at infrastructure sites, and parasitism of Savannah Sparrow nests was also about four times higher. The team monitored 427 nests and analyzed their distance from roads and infrastructure. Edges and perches associated with development can change how cowbirds move through the prairie and find host nests.
An extinction-risk assessment has not been added yet.
In Alberta prairie, cowbird abundance and Savannah Sparrow nest parasitism were both about four times higher at oil and gas infrastructure sites. The researchers recommend limiting perches and roads around new development.