The cuckoo is similar in size to the collared dove but has a longer tail. The adult male has a slate-grey head, breast and upperparts, with a sharp border against white with neat lateral, black barring underparts. The upper wing is darker grey or black. The underwing is paler. It has darker tail feathers tipped and spotted white. The female is similar to the male but browner with a buff breast band. Both sexes have a recurved bill with a yellow base and darker tips. Legs and feet are also yellow. Wings are pointed. The juvenile is rufous with a pale nape patch and has narrow white feather fringes.
The male’s famous 'cu-coo' call is eagerly anticipated as a sign that winter is ending and spring is finally on its way. Females make repetitive, bubbling notes. The juvenile has a squeaking hunger call.
Huw Lloyd, XC559502. Accessible at www.xeno-canto.org/559502.
The cuckoo eats insects, mainly hairy caterpillars and beetles.
A layer of bristles surrounds the cuckoo’s bill and protects its eyes when feasting on its preferred prey – hairy caterpillars.
The cuckoo is versatile in its habitat choice. It is mostly seen in open scrub and woodland, as well as grasslands and reed beds. It can be seen in all kind of woodland, farmland, alpine terrain, coastal heath. The cuckoo is widespread across the UK and is especially numerous in the Home Counties and south. They are a summer visitor. Adults will arrive from late March and will have departed by the end of August.
The cuckoo’s silhouette in flight can resemble a small falcon or hawk. However, unlike these, the cuckoo has a weak flight action and rapid wingbeats. And it rarely lifts its wings above the horizontal plane. It is easy to observe in the breeding season as it often perches in the open, on a telephone pole or fence post. When perched, it often droops wings and cocks tail a little. Females can spend a lot of time in the air looking for a nesting site.
Cuckoos are parasitic, laying their eggs in other species’ nests. Each female cuckoo concentrates on one host species, which is usually the same as the one that raised her. Her eggs will closely resemble that species’ eggs and so will be accepted. She will lay one egg in each host nest, and up to a dozen eggs can be scattered throughout its territory, although they have been known to lay up to 25. Eggs will be laid in April-June. The incubation period is 12-13 days. Once they have hatched, the cuckoo chick will forcibly evict the host nestlings or roll the other eggs out of the nest. It will then take advantage of the host’s instinct to feed its young, even though it looks nothing alike. Cuckoos reach sexual maturity at the age of two years.
Robin feeding Cuckoo chick
The average lifespan for a cuckoo is 4 years, but they are known to live for up to 13 years.
The cuckoo is migratory and European adults will journey to Africa in July. Juveniles will follow several weeks later. Somehow they know where adults go for the winter without contact between them. They are though to navigate using the Earth’s magnetic field. The cuckoo winters in tropical Africa. Birds from the UK have been tracked to their wintering sites in the Congo.
During their migration from Britain to the Congo, cuckoos cross the Sahara in one continuous 50-60 hour flight.
There are currently around 15,000 breeding pairs of cuckoo in the UK. However, their numbers have been in decline recently. This is thought to be due to the increasing droughts in southern Europe, which means they cannot put on enough fat reserves to complete their migration.
Known collective nouns for a group of Cuckoos are as follows:
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