The common cuckoo migrates from Europe and Asia to Africa while being raised by host birds.
It is a long-distance migrant whose European populations typically cross the Sahara and spend the winter in sub-Saharan Africa. Asian populations also move south into Africa or tropical Asia, depending on their breeding range. Satellite tracking has revealed complex routes and substantial differences among individual birds.
The cuckoo’s famous reproductive strategy is brood parasitism. A female lays an egg in the nest of another species, often a small songbird, and the cuckoo chick hatches early and ejects competing eggs or nestlings. Different cuckoo populations can specialize in different host species and egg appearances.
The common cuckoo is therefore both a migration subject and a classic example of coevolution. Its call is widely recognized, but only males produce the familiar repeated “cuck-oo” sound; females make different bubbling calls.