The Cuckoo - A Fostered Bird

What? Did I say 'fostered'? That little bird which we associate so closely to the cuckoo clock, raised by foster parents? Also, can we really associate the word 'parasite' to the reclusive bird? Actually, in both cases, the answer is 'yes'.

In the spring we watch as birds make their nests, lay their eggs, and tend to their young. We picture them the perfect parents. However, there are some species of birds throughout the world which make a habit of pawning that task off onto adults of an entirely different species. The European Cuckoo, known as the Common Cuckoo, whose mournful call is the one so closely associated with the sound of the "cuckoo clock," falls into this category.
The North American Cuckoo, which closely resembles the dove, builds its own nest, lays and tends to its own eggs, and rarely does it ever place an egg out for adoption. The female European Cuckoos however, only lay their eggs in the nests of other species of birds. Some cuckoos' undersides resemble a hawk, thus helping them obtain a host nest. The cuckoo egg will closely mimic the eggs of the host, in both size and color. If the host bird recognizes the intrusive egg it may either abandon the nest, or incubate and hatch the cuckoo egg. Shortly after hatching, the young European Cuckoo, using a scoop-like depression on its back, starts shoving out of the nest any solid object that it feels. Usually all of this is done prior to the young chick having any eyesight, or even able to hold its head up yet. With the disappearance of their eggs and rightful young, the foster parents are free to devote all of their care to the young cuckoo. It has been noted that the Common Cuckoo, with rare exceptions, lays only one egg in a nest, so that the large and hungry young bird can receive sufficient food. This can be quite a task for the host birds, since the cuckoo chick very often grows much larger than its foster parents, long before it can care for itself.

So, if the North American Cuckoo rears its own young, then why doesn't the Common Cuckoo? It's been hypothesized by some naturalists that the Common cuckoo lays her eggs, not daily, but at intervals over a span of two or three days. So hypothetically, if she were to make her own nest and sit on her own eggs, then the first ones laid would have to be left alone for awhile without being incubated, or there would be eggs and young birds of different ages in the same nest. Likewise, in Britain it's been noted that the cuckoo does not appear until mid-April, and then generally disappears around the first week in July. This period of only 11 weeks is not long enough for it to lay its several eggs, incubate and hatch them, then rear its offspring to an age at which they could fly strongly. This is a process that would take almost 15 weeks, at the least. So, for the Common Cuckoo, in order to meet its migration schedule and greet us with its melancholy call in early spring, fostering is the perfect solution.
In conclusion, these strange habits of the Common Cuckoo provide us with still another one of natures mysteries. When human children are raised by foster parents they generally take on the habits and vocal traits of the rearing parents. Whereas the same species of cuckoo, spread over a vast territory, each individually being raised by a different foster parent, will all still have the same distinct call. That same familiar call we hear when the engraved faced clock strikes the hour, and the little wooden doors swing open. Somehow I just can't picture the sound of a sparrow tweeting at the top of the hour.

The sound of the cuckoo lives on in these beautifully handcrafted Black Forest Cuckoo Clocks at tictoccuckooclock.com - View the original article at The Cuckoo - Fostered Bird