Arrival of birds

Since ancient times, many people thought just a wonderful, almost miraculous that the birds that winter in tropical countries, returning to his homeland as the time when we have spring comes. The continued need to return to their nesting grounds of birds waking up to winter when the approaching breeding season and increased activity of sexual glands. Associated with this excited state of the nervous system and is, apparently, the signal that gives impetus to the action of the migratory instinct. In favor of this view say many biological facts. One example - flights of an eagle. Do cuckoos puberty does not occur in the second, and only the third summer. And it turns out that such is not capable of laying eggs, the young cuckoo in the first spring after the flight did not return home but remain in the ground cabin for the second year, and only after another winter they have awakened the need to fly. Birds arrive at such a time when the local breeding spring comes, and with her there and the food that is needed and most birds, and her future chicks. We see that before all returning birds that may feed on thawed; flying birds arrive with the opening of reservoirs, and insectivores - at a time when there are exactly those insects that serve as their main food. Such a device - the result of long rebounds. Those birds that flew out of place, always risked to die. But the huge advantage given to those who fly on time, when appearing in nature they need food. After returning to us in mid-March, rooks at first fed on not melted yet, but already darkened roads, choosing from horse manure is not quite digested oat grain. In search of food and flies them to the landfill in a noisy group of jackdaws and crows. Rook opens the beginning of the spring return of birds. Shortly after the rooks and starlings arrive almost simultaneously with the larks. The average period of arrival of starlings to suburban areas - March 30, Lark-April 1. Both will notify you of their arrival sounding songs. A few days after they returned to males finches. At first they just shy of the votes cast to sing start after returning females. Almost at the same time, the thawing slopes, on high ground, where he managed to bare earth, there are flocks of lapwings just returned-pigolits.