The most well-known method of movement of animals – Migration. This type of movement is allocated a relatively high speed and is not accompanied by a lengthy occupation of the territory. Most migration is constantly repeated on For some time, and then talk about temporary migration. If such a loop is placed in the twelve months, then these movements are referred to as seasonal, are some examples: fall and spring flights birds annual migration of northern elk, deer, deer, moving from places with more snow in snowy areas, moving various antelope (Saiga and Russia in and the Caspian region) due to drought; movement seals seals, whales, including a variety of other animals are the same and move some fish. Saying 'look for fresh water', 'escape from the snow', 'looking for land', we mean not fundamentally different ways of movement (as it seems at first glance), but in general the same – repeated migration. This phenomenon each time takes on the character of mass movement, although not always clearly visible. Residents are accustomed to always meet conventional hooded crows.
But not everyone knows that these birds taken a liking to the December-March, landfills, and flocks of spending the night in our parks, were born far away from cities in northern forests, and move us only to survive the cold. Suit in March, and these birds are quietly freed place had flown from the south and outwardly no different brothers, flying away offspring start to their homeland in the and Vologda regions. Causes of fall migration is always complex. But the main of them – namely lack of food but not cold. There are cases where birds remain in the cold season among the strongest frosts. The main thing here – a very big place is not a closed snow cover the ground and not ice-covered river, where obtained turn up ample food. We must not forget that during winter daylight hours a little, and if during this time did not find enough food for a long night, the heat balance is violated and low temperature will take its toll.
That is the reason why the trees, which in the winter roost a bird, very common to see them frozen and flexed calf. And so it is independent, fun, carefree diving ducks, the usual migratory birds, polynyas in the ice, bird feeders zoo! And occasionally, and other reasons forcing the animals to leave their areas and move into others. For example, May's passage of roe deer on alpine pastures caused by insects: mosquitoes, Slepnev, spp. Reindeer summer constantly snorting, running from place to place, shaking his head. And, just climbing on some hills, calm down and relax. What's the matter? And just the wind rose, and small torturers hiding. And herds of animals migrate into a higher place.