Smelly Cuckoos Conserve Hosts’ Chicks From Carnivorous Bird

• “Cuckoos are not always the villains”
•  Cuckoos have a bad reputation as home-wreckers, taking over the nests of other birds and killing their chicks. But one species benefits its hosts by producing a smelly fluid that repels predators.

•  The chicks of great spotted cuckoos (Clamator glandarius) are usually happy to share a nest with two or three chicks of its host, unlike other cuckoos that will turf the chicks out. In turn, the birds that made the nest make no attempt to evict the cuckoo, even though it is a brood parasite.
•  These cuckoo chicks are known to emit a foul-smelling fluid from their cloacas.  “It’s pungent, produces a burning sensation in the throat, and looks like rotting matter.”