Clever Cowbirds

Learn more about these birds that are infamous for letting others raise their young

- MONICA CARDOZA

Perhaps no bird native to North America is more maligned than the brown-headed cowbird. This smallish blackbird lays its eggs in the nests of host species, letting unsuspecting parents raise its young-a breeding strategy known as brood parasitism.

Nest Invaders

The brown-headed cowbird is the most common brood parasite in North America. Both shiny and bronzed cowbirds, native to the American tropics and extending into some southern states, are also brood parasites.

Female brown-headed cowbirds parasitize more than 200 bird species, including the widespread northern cardinal; grassland birds such as meadowlarks, grasshopper sparrows and dickcissels; and the endangered Kirtland's warbler.

As a native species, cowbirds are protected under federal law, so it's illegal for humans to remove their eggs from a nest.