THE CUCKOO BIRD

The common cuckoo is well known both for its 'CUCKOO' call and its habit of laying an egg in the nest of another bird, then leaving it to be hatched and fed by foster parents. Unfortunately this deception often fails, but even so, more young cuckoos are reared that would otherwise be possible.

Migrating north from Africa, the first male cuckoo reaches Europe in mid-April. In the minds of most country people, spring only truly arrives when the first cuckoo is called.

The cuckoo’s two-note call is easily recognised, and can be heard in suitable habitat during most evening between mid-April and June.

The call carries over long distances, but it can be hard to spot the bird as it’s dull plumage makes it difficult to see when hidden within leafy cover

Where do Cuckoos live?

The cuckoo leaves Africa to breed in the cooler climates of Europe during the spring. Cuckoos tend to avoid towns and cities, but inhabit varied types of countryside, including woodland margins, open farmland, hedgerow and marshes. These habitats are most likely to offer abundant rearing sites.

In flight, the cuckoo - with its long, pointed wings and grey-flecked under parts - can be confused with a sparrow hawk. It is thought that this mimicry may be a deliberate ruse to frighten a smaller bird off its nest, enabling the female cuckoo to lay her own egg there.

Cuckoo migration

The adult cuckoo leaves its European breeding grounds in July to winter in the warmer climates of central or southern Africa. The following April the cuckoo will return to breed again.

Reared by its foster parents, the juvenile leaves Europe between August and September – several weeks later than its real parents – and yet still manages to find its way to the regular wintering area which it has clearly never seen or visited before.

Here the cuckoo will remain quiet in inconspicuous through the entire winter.

What do Cuckoos eat?

The cuckoo will find most of its insect diet in bushes and trees. It will also feed on the ground, but the cuckoo does walk rather clumsily. It snaps up any insect larvae it finds and is one of the few British birds to relish hairy caterpillars.

The cuckoo chick is fed on a diet of caterpillars, grasshoppers, flies, beetle and small snails. The female cuckoo specifically tries to find the nest of an insect eating bird species to act as foster parents to ensure the right diet for her young.

Cuckoo breeding

Alone among British birds, the cuckoo forces the rearing of its own young on to birds of a different species. The female cuckoo usually returns yearly to the area where she was reared, looking for foster parents of the same species that reared her. In late May, she lays one egg in about nine chosen nests while each fostering bird pair lays it sown brood.

It takes the female cuckoo just a few seconds to place her egg in the nest and remove one belonging to the host birds in order to keep the number of eggs left in the nest the same. To carry the disguise further, she chooses hosts of a species whose eggs closely resemble her own. Cuckoo eggs are small in relation to the mother bird’s size and quite closely match the size of the host’s eggs.

The cuckoo has evolved an especially short incubation period, so its chick usually hatches first. Although blind and naked when born, it manoeuvres the other eggs, one at a time, onto its back and heaves them out of the nest one at a time.

If any of the other eggs have hatched before the juvenile cuckoo, they too will receive the same treatments as the eggs. It the young cuckoo is unable to heave them out the nest, its greater size and insistence on being fed weakens the others until they can be successfully evicted.

The young cuckoo will grow far larger than its foster parents who continue to feed it regardless. At three to four weeks old the young cuckoo would have increased its size roughly 50 times and is ready to leave the nest.

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