Killing behaviour of adult brood parasites

Résumé fourni par la source

Avian brood parasites such as cuckoos or cowbirds lay their eggs in the nests of other (host) species. To fool their hosts, parasites evolved striking adaptations such as very fast egg-laying or eggs that mimic host eggs. Here, we present video-recordings where the common cuckoo females kill nestlings in host nests. This interesting behaviour has been also observed in other brood parasitic species and we speculate about its significance.