Settled, wandering and flying – these three main groups of birds allocate how they movements react to a change of seasons. If settled live all year in the same area, wandering gradually otkochevyvat to the South, then flying winter far from the main habitats.
Instruction
1. Settled birds live in the same places all the time. At the end of summer they can do small stocks for the winter: so, jays reserve acorns and nuts, titmouses and nuthatches – insects and seeds. They eat this food in the winter and in the spring when the stern is not enough.
2. The wandering birds unite in small flocks and gradually otkochevyvat to the South, but they have no constant places of winterings. Rooks and bullfinches, for example, look for areas low-snow, rich with berries and other food.
3. Migratory birds fly away in the fall from cold areas to the warm countries where they winter. They gather in the big packs consisting of hundreds and even thousands of individuals and fly to the South in the afternoon or at night (depending on a look). Birds eat, have a rest and continue a way, will not reach the habitual place of a wintering yet.
4. Orioles, nightingales and martins go to winterings at the end of summer though weather still warm and food for them is enough at this time. Other migratory birds, such as, for example, ducks and swans, fly away not earlier, than reservoirs on which they live will begin to freeze.
5. Birds during flights adhere to constant routes. On the same ways they depart every year on a wintering, and return home for a conclusion of baby birds in the spring.
6. It is by practical consideration established that at the migratory birds living in cages there comes the period of strong concern in the fall, and terms correspond to the period of autumn flight of free birds of the same look. According to scientists, the behavior of migratory birds is caused by the established seasonal alternations of conditions of their existence long ago. The birds living in tropical places also make migrations from seasonally droughty or storm areas. Thus, flights have the instinctive nature, and they were formed for several million years under the influence of change of seasons. In the spring of a bird return to native places for nesting.
7. The question as birds manage to be guided unmistakably in way to places of winterings and back, still is finally not resolved. Assume that an important role is played here by visual memory and ability to be guided by the sun. However many day birds are fed in the afternoon, and make flights at night that suggests an idea of orientation on stars or changes of magnetic field of Earth.