Birds are warm-blooded beings. Average temperature of their body is 41 °C. It means that they are capable to keep activity in cold season, but need bigger amount of food. For this reason many birds leave snow-covered native places and fly away on a wintering to the warm countries.
Seasonal migrations (flights) are movements of flocks of birds from places of nesting to the southern areas for winterings with the subsequent return back. The directions of migration of birds are very various. With approach of fall when duration of light day is reduced and goes down air temperature, the birds fly away to warm regions where it is simpler to them to find livelihood and to raise posterity. Not the cold snap, but lack of food is decisive factor, many birds eat caterpillars, frogs, insects and larvae.
Where birds fly away
Even in the southern regions of a bird make migrations. It is connected with the fact that near the equator there is a change of seasons of year. And birds fly away from droughty places there where there is water.
From the territory of northern Europe many birds fly away to Great Britain, the Mediterranean, southwest regions of Europe and also to Africa. They depart to areas where find for themselves habitual conditions of dwelling. That is forest birds during the wintering also live in forests, steppe and meadow — in fields and steppes. Thus, they migrate to those regions where find a habitual forage and conditions for life. The directions of migrations are defined not only a food supply in the place of a wintering, but also an opportunity to be fed in way. Therefore not all birds fly accurately from north to south, their route passes so that during long flight there was an opportunity to stop for rest and feeding. The first insectivorous birds leave places of nesting: martins, wagtails, cuckoos, swallows and starlings. As soon as there comes the fall, and nights become cool, swallows, martins and cuckoos gather in packs and go to the African continent. Starlings fly away to the region of the Mediterranean. Wagtails go to a wintering to Africa, Asia, or India.
What is the time flight lasts
Duration of flight is influenced by the speed and distance to the place of a wintering. Speed of flight of birds is various. For example, swallows gather speed to 55-60 km/h, chaffinches and siskins — 55 km/h, sandpipers on average up to 90 km/h. Birds with breaks as they stop for rest and feeding fly, stops can last from one to ten days. Therefore flight takes up to four months some birds. For example, sparrow spend for migration from the northern regions of Europe to the Central Africa two-three months. Weather conditions have significant effect on flight duration.