Most known flights swallows and swifts. These birds live in close proximity with humans, and although they fly away to spend the winter thousands of kilometers to southern Africa, they return to Europe from year to year, as a rule, to the same places. The arrival of these small birds marks the beginning of spring with us, whereas their departure means the approach of winter.
Swifts and swallows – fast, hardy flyers; they do not hesitate to overcome huge aquatic spaces or deserts, although their main food, flying insects, are rarely found in these places, especially in windy weather. A city swallow, for example, crosses the Sahara, flying at a great height without a single stop. The birds have to cover such long distances because in the temperate zone of the northern hemisphere at this time there are long summer days and the number of insects increases dramatically, which, on the one hand, provides abundant food for the nestlings, and on the other – provides parents with a fairly bright time , to have time to get this food. After all, the sooner the chicks grow up and get stronger, the higher their chances of safely reaching the south, to the wintering grounds. Continuous feeding and fast growth turn out to be very beneficial. Thus, migration for breeding, like most animal migrations, is closely related to food needs.
Every year the swallows return to their own nests if they survived. The chicks have to endure the torment caused by the hordes of ruthless parasites inhabiting these nests, and bird admirers who try to keep their pets in winter protect the lice, fleas, bedbugs and ticks there, unwittingly, the cause of suffering, disease and even the death of the true owners of the nest.
All swifts and swallows are forced to fly south before the onset of cold weather, when their prey disappears – insects. Among the species breeding in Europe, the most common are the village and city swallows. Their autumn flights to Africa have been repeatedly confirmed by ringed birds. British swallows usually winter in southern Africa, while birds ringed in Central Europe are more often found in Zaire, Nigeria, Morocco and Tunisia. Although it is impossible to indicate the exact location of the wintering of each European population, some general trends have been traced.
When adverse climatic conditions cause death or dispel insects that swallows and swifts feed on, many birds die from hunger. Cases of mass death of swallows, occurring from time to time, may partly give rise to the legend that these birds hibernate in winter. Naturally, small birds carry more heavy damage than large ones, and, in order to compensate for these losses, they lay more eggs.
Flight is not a speed match at all. Some swallows leave their summer homes at the end of July, while others linger until the end of September; the departure time depends on the deficiency or abundance in the given place of feed. Birds fly to the south in large flocks throughout the day, feeding on the fly. With the sunset, they descend to rest, choosing at the same time swampy places where you can safely hide in the thickets of reeds for the night. Both autumn flights and a long way back home last about 5-6 weeks with the difference that in spring birds fly in smaller flocks.
To cross the Sahara, a city swallow is forced to use all of its food and energy reserves, while pelagic species, such as petrels and albatrosses, are able to cover long distances with little or no effort or visible fatigue. These birds, having several limited areas of nesting, roam over the endless oceanic expanses, majestically floating on long, narrow wings, but laying eggs regularly return every year to the same places.
The creation of an air base on one of the Midway Islands has disturbed the life of a nesting colony of dark-spined albatrosses. Then an experiment was made, during which 18 adult birds were taken by plane to places that could become a new home for them, in particular, to the state of Washington, Alaska, Japan, New Guinea and Samoa. Two weeks later, 14 of these birds returned to Midway, with the fastest returning in just 10 days. Since then, before allowing airplanes to take off or land, the air base personnel has to make sure that the runway is free from albatrosses.
The large, variegated petrels nest from January to March on the islands of Tristan da Cunha. When the breeding season ends, they fly, describing a wide range, north to Newfoundland, Greenland, Iceland and the Faroe Islands, then turn south to the Azores, and finally return to Tristan da Cunha. The gray petrel also nests in the southern hemisphere, New Zealand, and spends summer on Labrador, in Greenland and Iceland. Wilson’s curl breeds chicks in Antarctica, and in the summer flies to the North Atlantic, which it reaches by doing a huge loop over the ocean. When comparing the flight directions of these birds with the direction of the prevailing winds, there is an assumption that the storm leaves fly northward driven by the south-eastern trade winds, which allow them to quickly pass away the poor tropical food. Then, carried away by the westerly winds, but much slower, they continue their way through the rich North Atlantic and turn to the southeast, following the winds blowing from the shores of Africa.
Many seabirds migrate over long distances, but only a few of them venture to travel longer than those that the Arctic Tern or thin-billed petrel make. Last nest on the coast of Tasmania, where it is called "sheep bird", in the south-east of Australia and the islands of the South Pacific. The total number of this species is estimated at tens of millions. Thin-beak petrels leave their nests in late April, heading from the east coast of Australia, first north to Japan. This part of the journey is 8850 kilometers, and they sometimes overcome it sometimes in a month. They spend June, July and August in the Arctic Pacific, and then return home, "riding a saddle" trade winds, helping them cross the eastern part of the water bank, thus describing a huge circle over the open ocean.
The white stork is also among the birds whose flight has been thoroughly studied. It nests in a wide area, a wide strip extending from the Netherlands to the western regions of the Soviet Union, in some parts of Spain and in northern Africa. The European white stork population consists of two parts, clearly distinguished by their flight routes. Birds nesting in Western Europe fly through France, Spain, cross the Strait of Gibraltar, and further south into western Africa. Those that nest in Eastern Europe and Asia – and the vast majority of them – cross the Bosphorus and fly through Turkey and Palestine to eastern and southern Africa. This difference in flight routes is probably due to the fact that storks cannot cross vast bodies of water over which there are no ascending air currents allowing them to soar. Migratory flocks of these magnificent birds, sometimes numbering hundreds of individuals, can be lifted upward by heated air to a height at which, despite their very impressive size, they look like barely visible points from the ground.
A wedge of cranes in the sky for everyone who happens to see him is a sight more charming than a pack of storks. Since ancient times, people have observed the flight of European cranes from their nesting sites in Scandinavia, Lapland and in northern Germany to wintering sites in Spain, northern Africa, Sudan and Ethiopia. In contrast to storks, which fly only during the day, cranes rarely use ascending air currents and are less dependent on atmospheric conditions. They fly both day and night and cross the Mediterranean Sea in its widest eastern part. Their manner of rhythmically and flapping their wings in flight allows them to fly in a famous, admirable wedge, while storks travel in a shapeless flock.
Crows, rooks and jackdaws constantly wander over a considerable part of their range. Thus, in winter, many rooks leave their nesting sites in Eastern Europe, moving to France, the Federal Republic of Germany and the GDR, Belgium, Holland and the southern part of England. Gulls, ducks and starlings also migrate widely throughout Europe. Migratory species include many species of small passerine birds. Slavki, thrushes, heaters, weavers and their relatives often cover vast distances, despite their small size and fragile constitution. Their annual travels can cover all of Europe and include flights across the Mediterranean and the Sahara to tropical Africa. But, since they mix up mostly at night, spending the day at rest and feeding, their flights often go unnoticed, although they sometimes cause interference (so-called "angels") on radar screens. In general, the species that are small and relatively secretive, such as flytraps, orioles, shrikes, Slavs, fly mainly at night, while falcons, pigeons, swifts, swallows, ravens, herons, storks, geese, ducks, gulls and some grain-eating Sparrows travel, as a rule, during the day. Many birds of prey are also migrants. Buzzards from northern Europe, where they spend the winter, fly to Africa and southern Asia, whereas in England these birds are sedentary and rarely travel more than 150 kilometers. Osprey flies, inhabiting most of the territory of Europe, as well as the steppe kestrel, common bream, common cheglo and red-footed falcon, wintering in southern Africa. Osprey flight paths that winter in tropical Africa pass either through Western Europe or through the Dardanelles and Asia Minor. These birds feed almost exclusively on large fish and are not able to feed themselves in the freezing lakes and rivers of Northern and Eastern Europe in winter. The remaining predatory migratory birds feed mainly on insects. Usually they gather in large flocks – one of these flocks, numbering more than a thousand otkoyedov, seen over the island Helgoland.
Among birds, eagles, vultures and other large predators look most impressive, and their migrations attract particular attention of ornithologists. Falcons are strong birds capable of rapid flight. The wings have a pointed shape, and the tail is relatively short. Representatives of some species lead a solitary lifestyle, while small cobers form large concentrations not only during flights, but also in nesting sites.
In the fall, they fly from Central Europe to South Africa, where birds such as, for example, the steppe kestrel, join together to search for food – flocks of winged termites. Larger falcons, such as the Mediterranean falcon, mainly prey on small rodents and songbirds. Small songbirds crossing the Sahara during flights are targeted by birds of prey, which increases the risk of them traveling through the desert. This does not mean that all migratory birds necessarily undertake long journeys. For example, some desert species, such as the ordinary runner and desert lark, which in early spring hatch chicks in the northern Sahara, move to the north with the onset of summer, since in the summer in the places of their nesting places it becomes too hot and dry. However, they fly no further than the coasts of Morocco or Tunisia. During the nesting period, birds move only within the territory immediately adjacent to their nest, whereas in winter they migrate from one place to another or scatter over a wide area. So, for example, ordinary seagulls, unlike silvery in winter, are settled on large spaces. Among other seabirds that are widely settled in winter, mention may be made of the fine-billed kayru and northern gannetwhales.