Cowbirds change their eggs' sex ratio based on breeding time

Brown-headed cowbirds show a bias in the sex ratio of their offspring depending on the time of the breeding season, researchers report in a new study. More female than male offspring hatch early in the breeding season in ...

Female cowbirds prefer less intense male courtship displays

In most species, females prefer the most intense courtship display males can muster, but a new study finds that female cowbirds actually prefer less intense displays. The full results are published May 2 in the open access ...

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