Raising children is a lifelong commitment. Parents pour a part of themselves into parenthood, giving hours of your life to making sure your children are looked after… well, the same can’t be said for cuckoos.
The common cuckoo takes a more unique approach to raising their children. In fact, they are known as a ‘brood parasite’. That is a type of animal that makes other animals raise their young for them.
This isn’t done with the knowledge of the other animal. Instead, female cuckoos target much smaller birds, watching their nest until they lay their own eggs. Then, the cuckoo swoops in a lays an egg in their nest, usually replacing one of the existing eggs with their own.
Usually, cuckoo eggs hatch earlier than the chosen host’s eggs. Within its first few days, the cuckoo chick instinctively pushes the other eggs out of the nest. It can even do this to newly hatched eggs. It does this using a specially adapted hollow in its back to move the eggs of the edge.
This behaviour is instinctive, the chick doesn’t even need to witness another cuckoo do it. Then, with all of the other competition gone, the host parents concentrate on feeding the cuckoo instead.
Even though the cuckoo will likely grow to be larger than the host bird, it will continue to be fed by them. Then, after roughly two to three weeks, the young cuckoo will flee the nest.
In some cases, a baby cuckoo may never meet its biological parents. Adults don’t build nests, incubate eggs or feed the chicks. Once the young cuckoo is independent, there is no real need to locate its real parents.
Why do birds continue to feed baby cuckoos?
Many birds have developed instincts that help them recognise their own eggs, and instinctively only feed their own. So why do cuckoos get around this? Cuckoos have evolved eggs that can mimic particular host species.
This chick’s behaviour also exploits natural instincts. It persistently begs to be feed, even when it is much larger than the host bird. Both cuckoos and the targeted bird breeds are trying to out evolve each other. Cuckoos are making better disguised eggs and the host birds are evolving better instincts.
