With the onset of autumn, birds living in temperate latitudes are forced to make "decisions" about where to stay. During migration, they will have a long flight through often inhospitable or dangerous territories, where there is practically nothing to profit from, to areas where young birds have never been before. On the other hand, to stay means to personally feel not the mercy of winter, at the same time, hoping that it will not be too painful.

Nomadic birds

Of course, every year their choice falls on “not staying”, but due to natural selection, each species has developed its own behavior, which has proved its greatest safety. For some, this choice is clear enough: birds that live in the Arctic, or those whose diet is completely dependent on insects, are forced to fly away. Others simply move farther south when their feed sources are slowly depleted. We call such birds nomadic. In this category, there are many species that feed on seeds, for example, various species of tits and finches, as well as some predators, in particular, the white owl and the winter sheep.

Partial migrant birds

Another group of birds, known as partial migrants, faces a different dilemma. In species such as finch, blackbird and robin, some individuals migrate, while others remain wintering near their occurrence sites or nesting territories.On the finch, in particular, it can be said that in its behavior there is a balance of two alternatives: during several mild winters, more and more birds begin to remain in the breeding territory, however, after one severe winter, almost all finches become migratory.

If the weather conditions in winter remain favorable, those birds that survive survive better than those that are at risk of migration, but if there is a fierce winter, migration proves less dangerous than wintering. Probably, the descendants of each type of bird inherit the behavior that is characteristic of their parents, and the relative number of individuals of each type will depend on the weather conditions of winter.

It has been observed that in species that are characterized by partial migration, young people migrate more often than adult birds, as well as females, as compared to males. Both young and female are less successful in competition for food; for example, in a brawl for food, adult birds and males more often become winners. And, therefore, young people and females are the group that is probably not able to survive in the winter on breeding territory, and therefore it is not surprising that they migrate mainly.

Birds that live in temperate latitudes must work hard in search of food; insects and fruits disappear, and so the birds that consume them in the summer are simply forced to change their diet. Most birds that remain wintering are waterfowl. In fact, the overwhelming majority of these birds spend their summers a little to the north, and with the onset of adverse weather they move southward and winter in a temperate climate.

There are more birds on the coasts in winter than in summer.Since these birds need ice-free water bodies, they do not move north or south, but from the center of the continent to its edges, where the weather conditions are less severe and not so ruthless due to the influence of warm ocean currents.