Why do some birds have a pear-shaped eggs?
The shape of the eggs of most birds is called – ovoid. But small variations are possible. Some birds have shortened or, on the contrary, elongated eggs, owls they are almost spheroid.
The pear shape is found in the eggs of many types of kelits. As a rule, these birds are laying for four eggs, which are placed by sharp ends to the center of the nest. Thanks to this form, the larger surface for surgery is involved, therefore, incubation efficiency increases.
Also have a pear shape of the egg from Kair. There are two types of these representatives of the clotted sublit: Tolstoculus and thin-fluffy. In our country, they nest on the new land – the archipelago in the Arctic Ocean between the Barents and Kara Seas, which is included in the Arkhangelsk region, and also north – on the archipelago, Franz Joseph’s archipelago. Inhabit that they and the Murmansk coast.
Cayra live on the northern seas, and for nestings, choose rocky sea cliffs, where the birds are satisfied with the birds. Many thousand birds are collected in the colonies, and in such conditions it is not so easy to choose a place. Unlike many others, Cayra do not build nests. They find a more or less flat platform on the rock and postpone the only egg right on it.
But with such a number of neighbors and in such a cramped eggs can be confused. To recognize them helps the coloring of the shell, it has different shades: red, yellow, blue, green, most often with a pattern, often quite intricate. Related paintings are found, but each egg is different from nearby. So parents manage to learn their egg after the absence.
The feature of the nesting was reflected in the form. Whether it is traditional, from the wind or careless movement of the egg can ride and fall from the cliff. Pear-shaped form provides him with stability. With a slight movement, it rotates around the sharp end and does not roll – like a light bulb lying on the table.