Those Crazy Cuckoo Birds!

Just by hearing the name you can already tell this species is very unusual. They are a very diverse group of birds. The most interesting fact about these birds is that when breeding the female lays her egg in another bird's nest. This is known as brood parisitism After the Cuckoo egg has hatched the new parent will raise the Cuckoo as its own.  But why in the world do the other birds believe that the baby Cuckoo is actually their offspring and why do Cuckoo birds breed in this fashion? Are cuckoo birds just smart or are the other birds really dumb?
Throughout their generations, Cuckoos constantly evolve new strategies for improving their skills and getting their egg into a host nest.  The female Cuckoo is the only species that can mimic anothers egg markings, but each individual female Cuckoo can only lay it's one unique egg type to its particular host. They usually lay one egg in the nest of smaller birds (i.e.reed warbler) and it chooses a nest specifically based on the color of the host eggs which matches her own. They'll eat one or more of the eggs to make room for the Cuckoo egg. The Cuckoo chick is also able to replicate the sounds of the host's chicks. When the cuckoo hatches from its egg, it will then push out the other eggs in the nest leaving itself to be the only child. Barely a day old, the chick instinctively knows what to do by rolling any host eggs or other chicks over the edge by using the indentation on its back.  Sometimes the mother Cuckoo won't kill off the hosts eggs, but instead when the chick hatches it will starve out the other chicks to death. The new parent raises the cuckoo as its own, frequently feeding and caring for it. The host never seems to notice the different attributes its child has; such as its huge size. The foster parent will just assume that whatever hatches in their nest is their own.
It would seem that this is a natural "survival of the fittest" that the cuckoo birds are employing but could there be another aspect to this strange behavior? Could it be that the Cuckoo parents have no interest in taking care of their infant, are they seeking world domination, are they cheating mother nature, or something else?
It also appears that some host parents are getting smarter at this game now as well. Maybe they're not as dumb as we think. Recently other species have been able to detect the parasite egg and remove it from their nest. Some parents have learned to recognize the cuckoo's characterization and attack before they can switch eggs. But still many other birds do not see the difference and fall prey to the usual Cuckoo trick. Are other birds more naive than others? Could it be because they've yet to take up the arms race.


My thoughts on this are that the Cuckoos are not lazy, but by not having to raise each chick on their own they are able to focus on breeding more and therefore insuring that they can have more offspring. It may be that the Cuckoo is lazy too, but it has allowed the species to survive as well. Seeing how the birds have adapted to learn how to spot the Cuckoo's eggs and destroy them. This is a classic example of natural selection. Those birds that learned to spot the eggs survived and those that didn't died off.

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