Common Cuckoo

The Common Cuckoo is a slim, long-tailed, grey bird with pointed wings, superficially resembling a small falcon or sparrowhawk in flight, an impression reinforced by its barred underparts. Males and most females are blue-grey above with fine dark barring below, though a rarer rufous-brown "hepatic" morph occurs in some females.

It is best known as an obligate brood parasite: females lay their eggs singly in the nests of small host species, such as Reed Warblers, Meadow Pipits, or Dunnocks, leaving the host to raise the cuckoo chick, which typically ejects the host's own eggs or young from the nest soon after hatching.

Key field marks

• Slim body, long tail, and pointed wings giving a hawk-like flight silhouette
• Blue-grey upperparts with fine dark barring on white underparts
• Yellow eye-ring and yellow legs
• Male's far-carrying two-note "cuck-oo" call

Similar species

• Eurasian Sparrowhawk shares a similar grey, barred appearance and hawk-like flight, but has a hooked bill, rounder wingtips, and different flight action with quick wingbeats and glides.
• Kestrel hovers and has a different, more rufous plumage.

The distinctive "cuck-oo" call is the most reliable way to confirm this species, since its plumage and flight can suggest a small hawk at a glance.

Habitat

Occupies a very wide range of habitats depending on locally available host species, including woodland, farmland, reedbeds, heathland, and upland moorland.

Range

Breeds across almost all of Europe and temperate Asia; a long-distance migrant wintering in sub-Saharan Africa.

Migration

Arrives on breeding grounds in April, with adults typically departing again for Africa as early as July, well before their fostered young, which migrate independently later in the season guided by instinct alone.

Behavior

As a brood parasite, the female Cuckoo watches host nests, removes one host egg, and lays a single mimetic egg in its place, often specializing on a particular host species whose egg pattern her lineage has evolved to match. The chick hatches quickly and instinctively ejects the host's eggs or chicks from the nest, monopolizing the foster parents' care.

Voice

The familiar far-carrying "cuck-oo" call is given by males to advertise territory in spring; females give a distinctive bubbling chuckle.

Feeding

Feeds mainly on insects, with a particular preference for hairy caterpillars that many other birds avoid.

Nesting and breeding

Builds no nest of its own; instead, the female lays eggs directly into the nests of host species, leaving all incubation and chick-rearing to the unwitting hosts.