快猫短视频

FEMALE cuckoos are famous for duping other birds into raising their young.
Now British scientists have shown that the chicks play a part in brainwashing
their foster parents into providing them with large amounts of food.

A single cuckoo chick in a reed warbler鈥檚 nest will eject its hosts鈥� young
and be raised alone. When warblers raise their own brood, they adjust the
feeding rate to the number of chicks present. But a cuckoo chick somehow
commands five-star service, and persuades its hosts to bring it as much food as
they would give four of their own chicks.

Some researchers have speculated that it is the cuckoo chick鈥檚 size that
stimulates the reed warblers to provide bigger feeds. Nick Davies, Rebecca
Kilner and David Noble of Cambridge University tested this idea by putting
blackbird chicks, which are about the same size as their cuckoo counterparts, in
the reed warblers鈥� nest.

At first they found that the blackbird chicks were given much less food than
the cuckoo. But when the researchers installed loudspeakers broadcasting the
rapid squeaky begging call of the cuckoo chick, the hosts brought as much food
to the young blackbirds as to a cuckoo chick (Proceedings of the Royal Society
series B, vol 265, p 673). This cry, says Davies fools the unsuspecting birds.
鈥淚t sounds remarkably like a whole brood of reed warblers,鈥� he says.

Anders M酶ller, a behavioural ecologist at Pierre and Marie Curie University
in Paris, says the work shows what a large part deception plays in the cuckoo
lifestyle. Cuckoos are known to produce eggs that mimic the appearance of their
hosts鈥�. 鈥淚t demonstrates that mimicry occurs also at the chick stage,鈥� he says.