Common Cuckoo

The Common Cuckoo is best known for its far-carrying two-note call and its brood-parasitic breeding strategy, laying eggs in the nests of other, smaller songbirds. Its plumage closely mimics that of small hawks, which may help reduce mobbing by host species while it searches for nests.

Common Cuckoo flight feathers are long and pointed, giving a falcon- or hawk-like silhouette in flight, while the underparts are finely barred grey and white, closely resembling the barred underside of a sparrowhawk - a case of convergent plumage pattern rather than close relation. Upperparts are plain blue-grey in most adult males and many females, while a rarer rufous morph, found mainly in females, is barred rufous-brown and dark brown throughout instead of grey. The tail is long, graduated, and dark with small white spots or notches along the edges of the feathers, visible as a spotted fringe when the tail is fanned.

Most males and many females show the grey morph described above; a rufous-barred morph occurs in some females and is less common. Juveniles are heavily barred rufous-brown above and below, often with a small pale patch on the nape, quite different from the more uniform grey adult. Adults undergo a complete molt, largely completed on the African wintering grounds rather than the breeding range.

Common Cuckoos occupy a very broad range of habitats including woodland, farmland, reedbeds, and heathland, wherever suitable host species are common. The species breeds across Europe and much of Asia and is a long-distance migrant, wintering in sub-Saharan Africa.

The Common Cuckoo is a brood parasite, with females laying single eggs in the nests of small songbirds such as warblers, pipits, and wagtails, leaving the host species to raise the chick. The male's familiar two-note "cuck-oo" call is one of the most recognizable bird sounds in Europe, given from exposed perches in spring. The species itself builds no nest. IUCN status is Least Concern, though populations have declined in parts of its range.