However, field observations suggest that a given female cuckoo tends to parasitize just one species, and lays eggs of the appropriate type. But how does a female find? The explanation could lie in inherited preferences, or in the? Alternatively, the cuckoos could return to the geographic location where they were born - the cuckoo is a migratory species.
A fourth hypothesis proposes that female cuckoos choose a group of host species with similar egg and nest types and select a nest at random withion this group. However, this last hypothesis does not provide a mechanism underlying a female? Taborsky and colleagues suggest, instead, that cuckoos look for nests in a familiar type of habitat - deciduous woodland, say, or low-lying vegetation.
This is not quite the same as natal philopatry, as the type of habitat is not necessarily tied to the geographical location in which the cuckoos were fledged.
However, a cuckoo is more likely to find hosts of the appropriate species by following certain habitat preferences. The researchers build their idea into a general scheme of cuckoo behaviour that accommodates a diversity of views - first, the cuckoos return from their African wintering grounds to the geographical area where they were born natal philopatry.
Once there, they select an appropriate habitat in which to search habitat imprinting , and once in the right habitat, employ finer criteria to select the? Imagine them launching into the night skies at dusk. They then fly nonstop through that night and all the following day, then another night and day, and finally a third night, before they have the chance to feed once more.
The migration route varies, and this provides the clue to the varying fortunes of our summer cuckoos. In autumn, most English cuckoos go southwest through Spain, but increasing droughts in SW Europe have made it difficult for them to put on sufficient fat reserves and only half of the tracked birds survive the long desert crossing.
This heavy mortality on migration matches the dramatic decline in our English breeding cuckoos; we have lost two-thirds of them in the last 30 years. By contrast, most Scottish and Welsh cuckoos take a different autumnal route, south-east through Italy. This is reflected in the better fate of their breeding populations; Welsh cuckoos have declined much less than in England, and in Scotland, numbers have remained stable.
As cuckoos disappear from the English countryside, we lose part of our cultural heritage. The cuckoo never raises its own offspring. Instead, it lays its eggs in the nests of other birds; just one egg in each host nest. Any host chicks will get thrown out too. Once the cuckoo chick has claimed the nest to itself, the host parents are then tricked into raising a young cuckoo instead of a brood of their own.
Two favourite hosts in Britain are reed warblers in marshland and meadow pipits in moorland. Individual female cuckoos specialise on one host species and there are genetically distinct cuckoo races. Reed-warbler-specialist cuckoos lay a greenish spotted egg, just like those of reed warblers, while meadow-pipit-specialist cuckoos lay a brownish spotted egg, just like those of meadow pipits.
Both these hosts reject eggs unlike their own, so the specialised cuckoo-egg mimicry is essential to fool them. The female cuckoo also needs secrecy to succeed, because if the hosts see her at their nest they are alerted to inspect their clutch more closely. She glides down to the host nest from a hidden lookout perch, removes a host egg, lays her own in its place, and is off — all within a second visit.
As she departs, she often gives a chuckle call, as if in triumph. This is perhaps the most remarkable trick of all. Look at the tail to distinguish a cuckoo, which has a graduated tail. Cuckoos eat invertebrates, and hairy caterpillars are a particular favourite. They find their food in bushes and trees.
They are diurnal, this means they are active during the day. Host birds are tricked into carrying on feeding the often much larger cuckoo chick because of its call, which mimics a whole nest of hungry host chicks. Cuckoos court multiple mates during the mating period in April. As brood parasites, cuckoos do not raise their own young, instead laying eggs in the nests of other birds, which raise the chick thinking it is one of their own.
The nests of dunnocks, meadow pipits and reed warblers are favourites. Females wait until the host has left the nest, sometimes spooking the bird away, then swoop in to lay a single egg. The chick hatches after around 11 days. It will push any other eggs or chicks out of the nest, ensuring it receives the sole attention of its adoptive parents. They will continue to feed the young cuckoo, even though it may grow to two or three times their size.
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Choose a species The name cuckoo is onomatopoeic, which means that it is taken from the bird's call like, for example, curlew and hoopoe.
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