Adaptations for Brood Parasitism in Cuculus Cuckoos

Abstract

Brood parasitism is a breeding habit of birds, in which eggs are laid into the nests of other birds. Cuculus cuckoos, representative of such brood parasites, visit the laying nests of hosts, and remove one egg from the nest before laying their own egg. A particular female cuckoo lays one egg in one nest. It takes only a few seconds for the cuckoo to lay an egg. Cuckoo eggs are larger in size and similar in color to host eggs. Cuckoo young eject host eggs or young from the nest by placing them onto the scrape of their back. All of these characteristics are adaptive and contribute to higher breeding success. Many of them evolved through interactions with host species. One female cuckoo may lay up to 25 eggs in one breeding season. This large number of eggs to be laid is probably due to the greater contribution of energy released from nesting and feeding into egg formation.