Sunday, May 15, 2022

Cowbirds Are Brood Parasites


The tree cover provided by old farm windbreaks and shelterbelts provides a near-perfect habitat for the brown-headed cowbird.

The brown-headed cowbird (immature bird pictured) is a brood parasite species which lays its eggs in nests of other birds and leaves them for the host bird to raise.

Because cowbird eggs hatch a few days before those of their hosts, the larger cowbird chick is able to push out the eggs and chicks of the host bird, thereby winning all the food resources for itself.

The destructive capacity of the brown-headed cowbird is hard to overestimate: a single female can destroy the clutches of 20 or more song birds in a single season.

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