Flights of birds. Flights, or seasonal migrations of birds Flight of birds
Bird flight annual more or less distant movements of all or part of the bird population from the nesting area to the wintering area with the return of at least some of the birds back; one of the types of Animal Migration. P. p. - adaptation to seasonal climate fluctuations, allowing the use of nesting areas suitable for life in one season (in the Northern Hemisphere it is summer, in the tropics - a humid period) and unsuitable in other seasons. P. p. Is a hereditarily fixed phenomenon that arises as a result of the dispersal of a species to new territories or changes in the conditions of existence in its homeland. Therefore, some populations of the species can be sedentary, others migratory. The timing of P. p. Often depends on the method of feeding: most granivorous birds arrive earlier than insectivores; among the latter, species that catch insects in the air (swifts, swallows) arrive later. Some species, such as waders, arrive early and fly away early, but usually the earlier the birds arrive, the later they fly away. In spring, in most bird species, males fly earlier than females, adults - earlier than young ones; in the fall - on the contrary. The flight range depends on the ecological needs of birds (grain-like birds winter closer to their nesting sites, insectivores - to the south, waterfowl - not to the north of the freezing point of water bodies, etc.), the success of wintering competition with other species, local migrants, and the history of the species. The farthest flight is made by Arctic terns: they nest in the Arctic, and winter in the Antarctic. Crows, rooks, snow buntings, and many blackbirds overwinter close to nesting sites. If the nesting and wintering areas overlap each other, then in the coinciding part nesting birds (and winter are replaced by more northern ones, which creates a false impression of settledness (for example, crows). Often more southerly populations are settled or fly away not far, more northern ones winter farther south. Females of some species winter southerly males of many species that start breeding at the age of over 1 year, first yearlings spend the summer outside the nesting area.Some species make intermediate flights: siskins and tap dancers - after the first nesting, fly further to the north, where they nest again; mallards - to molting places (See Moulting) (males - after females sit on eggs, females - after breeding), after breeding, starlings - in the direction of wintering. km; in other species, roaming is shorter, often within several km. The autumn breeding season can thus begin either from roaming, or after an intermediate flight, or from the nesting and hatching sites of chicks. Most bird species begin their migration after molting, in some, molt is suspended during the flight, and still others molt during wintering. Changes in food and weather factors during the corresponding season can stimulate or suspend the migration of some species of birds. But in other seasons, deterioration of conditions does not cause P. p., Although it can lead to the death of birds. The ability to fly is manifested as a result of the development of a migratory state in birds, which is accompanied by the deposition of fat in their body, the appearance of special daily biological rhythms (see Biological rhythms) of activity, the desire to move in a certain direction and the formation of flocks. In spring, the signal to prepare for the flight for many bird species is an increase in the length of the day. The terms of preparation for the autumn P. of the item are established in the spring and are further controlled by the endogenous "okologodovy" biological rhythm. In birds migrating over long distances, the flight begins immediately after the completion of preparation for it. For birds flying away close, the departure time can be accelerated or delayed by external conditions. The direction of the P. n. Is due to the location of places favorable for wintering and their availability. Many species from the European part of the USSR fly southwestward to Western Europe and Africa. Starlings from the Baltics fly to the west, to the British Isles, and lentils from Europe to the southeast, to South Asia. When choosing a flight route, birds make the most of the landscapes favorable for this species; however, birds can cross obstacles such as the Mediterranean Sea, the Sahara or the Gulf of Mexico when necessary. The ability to find the right direction of flight is an innate property. Some birds are guided by the sun, stars, and possibly by the geomagnetic field (see. Orientation of animals). Before departure, young birds develop the ability to find nesting territory in spring, and in wintering places - a place of last year's wintering. As a result, as the ringing of birds shows, they return from year to year to their nesting and wintering grounds. In siskins, crossbills, this feature is weakly manifested; some species roam all winter. Most birds fly day and night, only a few species only during the day. Daytime P.P. begins after sunrise and lasts 2 - 5 h; sometimes flight activity increases at the end of the day. Night P. begins in 40 - 60 min after sunset and usually lasts all night. At night, P. p. Occurs at an altitude of several hundred m up to several km. During the day, it can also occur high, but sometimes (with a headwind or when flying at a close distance) birds fly at a height of several m - several dozen m. Most birds fly in flocks, only a few species fly alone. Flocking is beneficial for orientation, reduces predator damage, synchronizes bird behavior, and possibly facilitates transfer of experience. There are various structures of the flock - a line, a string, a wedge, and more complex ones - multi-layered. The formation of the flock facilitates the use of aerodynamic conditions and expands the view. Average speed P. p. From 30 - 50 km per day (for closely flying tits) up to 200 - 300 km per day (in far away warblers, wagtails, flycatchers). P. p. Usually lasts 1 - 2 month and its duration depends little on its range. The speed increases towards the end of the flight; therefore, in the middle latitudes the autumn season is slower than the spring season. Birds do not fly every day, they alternate 1 - 2 days (or nights) of flight with a stop for 5 - 10 days. The energy expenditure in flight is 12-14 times higher than at rest, and the fat reserves of birds are quickly depleted. During a stop, they accumulate again. The more energy is spent on the flight to the wintering site and back, the less energy is spent on thermoregulation during the winter as a result of wintering in warmer conditions. Lit .: Menzbir MA, Bird migration from a zoogeographic point of view, M. - L., 1934; Promptov A. N., Seasonal migrations of birds, M. - L., 1941; Steinbacher I., Flight of birds and their study. per. from it., M., 1956; Griffin D., Flights of birds, trans. from English, M., 1966; Dolnik V.R., Mysterious flights, M., 1968; Mikheev A.V., Flights of birds, M., 1971. V.R.Dolnik.
Big Soviet encyclopedia... - M .: Soviet encyclopedia. 1969-1978 .
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See what "Bird flights" is in other dictionaries:
BIRD FLIGHTS- annual relatively long movements of birds from the nesting area to the wintering area with the return of at least some of the birds back; one of the forms of animal migration. Flight adaptation to seasonal climate fluctuations and related factors ... Biological encyclopedic dictionary
FLIGHT OF BIRDS- mass migration of birds from nesting sites to climatically more favorable areas (autumn migration of birds) for wintering and their return (spring migration of birds). Migration of birds adaptation to seasonal climate changes and dependent on this presence ... ... Ecological Dictionary
World Day of Migratory Birds- World Day of Migratory Birds. Every second Saturday in May, at the request of ornithologists at the Cornell Laboratory, USA, since 1993, World Migratory Birds Day has been celebrated. And, although this holiday is considered international, mainly events related to ... ... Wikipedia
Migratory birds
Migrant- Wedge of gray cranes. By migration, or flight of birds, we mean the movement or relocation of birds associated with changes in ecological or forage conditions, or with the characteristics of reproduction. The ability of birds to migrate is promoted by their high ... ... Wikipedia
flight- a; m. 1) to fly over fly. Flight over the mountains. Flight of birds to the lake. Flight of a butterfly from flower to flower. 2) Missing the target of an artillery shell flying further than the target. Flight! said the gun commander ... Dictionary of many expressions
Migratory birds- birds that annually make more or less distant flights from nesting sites to wintering grounds and vice versa. In contrast to the P. p., For nomadic birds the wintering area is the nearest ecologically favorable area, not separated from the area ... ... Great Soviet Encyclopedia
migratory- oh, oh. 1) Flying away for the winter to the southern countries (about birds) The first birds are flying. A flock of migratory birds. 2) trad. poet. Easy and fast moving, flying over. P th blizzard. N th blizzard ... Dictionary of many expressions
FLIGHT- FLIGHT, flight, husband. 1.units only. Action according to Ch. fly over fly. Shoot a bird while flying. || Seasonal migration of birds to other countries. Flight of cranes to the south. 2. In aviation, a long-range flight from one point to another by ... ... Ushakov's Explanatory Dictionary
Abstract in biology on the topic:
Bird flight
Vladivostok
Even in ancient times, people paid attention to the annual migrations of birds. This phenomenon in the life of nature is really wonderful. With the onset of the autumn cold, many of the birds that lived in our forests and fields in summer disappear. Instead of them, others arrive, which we did not see in the summer. And in the spring, the disappeared birds reappear. Where were they and why did they return to us? Couldn't they have stayed where they flew for the winter?
Some birds disappear for the winter and others appear not only in the North. In the south and even near the equator, birds make seasonal flights. In the north, birds are forced to fly away by a cold snap and lack of food, and in the south, a change of wet and dry seasons. Where birds breed, that is, in the north and in temperate climates, they spend less of the year, and most of them spend on flights and living in wintering grounds. However
less annually, migratory birds return to where they hatched last year. If the bird did not return to its homeland in the spring, it can be considered that it died.
The better a bird finds its homeland, the more likely it is to survive and breed. This is understandable: after all, any animal, including a bird, is most adapted to the conditions where it was born. But when living conditions change at home - a cold snap sets in, food disappears, the bird is forced to fly to warmer and more abundant places with food. Birds that make such travels are called migratory.
But there are birds that all year round find suitable conditions for existence in their homeland and do not fly. These are sedentary birds. Saddlers, for example, are the inhabitants of our forests: wood grouse, hazel grouse. With a favorable winter, some birds remain at home, and in severe winters they wander from place to place. These are nomadic birds. These include some birds that nest high in the mountains; in the cold season, they descend into the valleys.
Finally, there are those birds that are settled in favorable winter conditions, but in unfavorable years, for example, with a poor harvest of seeds of conifers, fly far beyond the boundaries of their nesting homeland. These are crossbills, waxwings, blue tits, walnut, tap dance and many others. The saji nesting in the steppes and semi-deserts of Central and Central Asia behave in the same way.
Some widespread bird species are migratory in some places and sedentary in others. The Hooded Crow from the northern regions of Russia flies to wintering in the southern regions, and in the south this bird is sedentary. The blackbird is a migratory bird in our country, and a sedentary one in the cities of Western Europe. The house sparrow lives in the European part of Russia all year round, and from Central Asia it flies to India for the winter.
The wintering grounds for migratory birds are constant, but they live there, not adhering to certain narrow areas, as during nesting. Naturally, birds winter where natural conditions are similar to living conditions at home: forest - in wooded places, coastal - along the banks of rivers, lakes and seas, steppe - in the steppes.
In the same way, during flights, birds adhere to familiar and favorable places for them. Forest birds fly over woodlands, steppe birds - over steppes, and water birds move along river valleys, over lakes and sea coasts. Birds nesting on oceanic islands fly over the open sea. Crossed by large sea areas and some mainland birds. For example, kittiwakes nesting off the coast of the Kola Peninsula overwinter in the Northwest Atlantic and reach the west coast of Greenland.
Sometimes birds have to overcome unusual terrain during the flight, for example, deserts. Birds try to quickly pass such places and fly in large areas with a "wide front". Autumn departure begins after young animals learn to fly. Before leaving, birds often form flocks and sometimes migrate over long distances. Birds leave places with cold climates earlier than more warmer climes; in the spring they appear later in the north than in the south. Each type of bird flies and arrives at a certain time, although, of course, the weather affects the timing of departure and arrival.
Birds of some species fly one by one, others - in groups or flocks. For many species, a certain order of arrangement of birds in a flock is characteristic. Finches and other passerines fly in disorderly groups, crows - in sparse chains, curlews and magpie-waders - in a "line", geese and cranes - in a "corner". In most birds, males and females fly at the same time. But in the finch, the females fly away in the fall earlier than the males, and in the storks, the males arrive in their homeland in the spring earlier than the females. Young birds
Cranes fly like a wedge
sometimes they fly off to winter earlier than the old ones. Some birds fly during the day, others at night, and during the day they stop to feed.
The flight speed of birds on the flights is relatively low. For example, a quail has 41 km / h. The highest speed for a black swift is 150 km / h.
Flight altitude is average. Many small passerines fly low above the ground. Even lower - with a headwind, strong clouds, precipitation. Large species fly approximately at an altitude of 1-2 thousand meters. m, medium and small - about 1000-500 m. However, in the Himalayan region, mountain geese were observed on migration at an altitude of about 8 thousand meters. m above sea level. At such a flight speed, the birds could reach the wintering or nesting area in a relatively short time. But in reality, the flight usually takes a long time. It is believed that birds on long-distance flights cover from 150 to 200 km. Thus, for example, passerine birds spend 2-3 and even 4 months on a flight from Europe to Central Africa.
Birds usually fly faster in spring than in autumn.
Some birds have to cover very long distances during flights. Arctic terns from the Far North of America fly to winter for 10 thousand. km to the south of the American continent, to the south of Africa and even to Antarctica. Bee-eaters nesting in Asia overwinter in South Africa. About 30 species of birds nesting in Eastern Siberia overwinter in Australia, Far Eastern red fawns in South Africa, and some American waders in the Hawaiian Islands. In some cases, "land" birds are forced to fly over the open sea from 3 to 5 thousand. km.
The direction of flights is determined not only by the location of wintering grounds and nesting grounds, but also by the places lying on their way, favorable for feeding and resting. Therefore, not all birds in the northern hemisphere fly from north to south in autumn. Many northern European birds fly west and southwest in autumn and winter in Western Europe.
It also happens that birds of a certain species from the northeastern zone of the European part of Russia fly southward to the Caspian Sea, and their relatives from Western Siberia fly to the southwest.
North American birds usually move south towards the equator, but some species fly farther, even towards Tierra del Fuego.
Black-throated loons from Western and Central Siberia fly through the tundra to the White Sea and from there, partly by swimming, migrate for wintering to the shores of Scandinavia and to the Baltic Sea.
If birds of the same species nest both in the north and in the south, then the inhabitants of the north usually winter more south than their southern relatives. For example, tundra falcons from Siberia hibernate in the South Caspian Sea, North Africa and South Asia, while falcons of the same species, nesting in the middle zone of the European part of Russia, make relatively small migrations and hibernate not south of Central Europe.
A small bird, the Dubrovnik Bunting, makes a significant flight. It nests in floodplain meadows of river valleys, such as the Moskva River and Oka. It arrives late in spring, at the end of May, flies away earlier than other passerines, and, as we managed to trace, in autumn it flies for wintering across Siberia and the Far East to southern China. The wintering grounds of hunting and commercial waterfowl are of great economic importance. Most of the ducks nesting here winter outside the borders of Russia - in Northwestern Europe (in the Baltic and North Seas), in the Mediterranean Sea, in the lower Danube, in the Nile Valley, in Asia Minor, Iran, India, in Southeast Asia ... But many different birds winter on the territory of Russia - in the south of the Caspian Sea, and in the former republics of the USSR in Azerbaijan, Turkmenistan, near the Black Sea, on the lake. Issyk-Kul in Kyrgyzstan. In these places in winter, a huge number of ducks, geese, swans, waders accumulate. For their protection, special reserves have been created. During the flight and wintering, a lot of birds die. For example, tens of thousands of ducks die every winter in the Caspian Sea and in the Transcaucasus. They die from lack of food, severe frosts, deep snow, and especially from storms at sea. Waterfowl often die from oil spilled in the Caspian Sea by steamers. The oil stains the feathers, sand sticks to them, and the birds can no longer fly. In the south of Ukraine, the change of rains and cold snaps destroys a lot of bustards. In the rain, their feathers get wet and freeze from the coming cold snap.
There were many guesses and assumptions why birds fly away for the winter and how they find their way during flights. In some birds, young birds fly off first, and then old birds. Consequently, no one shows the young the way to winter.
The usual statement that birds fly north in spring and south in autumn is a significant oversimplification, although it is almost as true as any short generalization. Vertical migrations of birds from ridges to valleys are a fairly well-known exception, and in tropical rainforests, shorter movements are observed for each population due to feeding conditions during rainy and dry periods.
Ocean bird migrations can take place in almost any direction. For instance. The White-fronted Tern, nesting in New Zealand, flies almost due west in autumn to spend the winter on the east and southeast coast of Australia. The American red-headed duck, which nests on the prairie along the shores of small lakes, flies to winter almost directly to the east - to the Atlantic coast, the pink starling wintering in India flies to nest to the northwest, in the steppes of Turkey and southern Russia.
In the Southern Hemisphere, it is quite understandable that the direction of flights is the opposite: in the fall, birds fly to winter to the north, and to the tropics. Moreover, such migrations are undertaken here by a smaller number of land birds than might be expected. This is partly due to the fact that in the Southern Hemisphere, the land area located in a temperate climate is much smaller than in the Northern. It should also be taken into account that the birds of the Southern Hemisphere have been studied much less well. Birds of the southern seas also make long-distance migrations, especially species nesting on the shores and coastal islands of Antarctica. Even penguins, who can only swim by swimming, migrate hundreds of kilometers south in the spring, to the Antarctic region, and return to warmer waters in winter. Perhaps the most well-studied is Wilson's flight. It is one of many species of petrels about the size of the American Wandering Thrush. The sailors call it "Mother Carey's chicken." Usually these birds fly over the very waves, often touching the water with their membranous legs, as if helping the flight. Although storm petrels, when viewed from a ship, look weak and moth-like, they can easily withstand ocean storms and spend most of their lives offshore. Wilson's storm petrel nests on small islands between southern South America and the surrounding Antarctic regions, especially South Georgia, the South Shetland Islands and the South Orkney Islands. During March and April - the autumn months of the Southern Hemisphere - these storm petrels migrate north into the tropical waters of the South Atlantic. In June, they are plentiful off the eastern shores of the United States, significantly more than the native northern storm petrels nesting at this time on the islands off Maine and Nova Scotia. During the northern summer, they spread widely across the North Atlantic from New England and the Gulf of St. Lawrence to the Bay of Biscay and the northwestern coast of Africa. In October, Wilson's storm petrels begin to move southward and are found already from the tropical waters of the Atlantic, especially off the African coast, to the south to the places of their nesting colonies. As the picture below shows, these birds, despite their small size and relatively slow flight, migrate almost as far as the Arctic tern, whose exploits we have already spoken with admiration for.
Observations of Wilson's storm petrels in the North and South Atlantic. White circles indicate places where they were noted in January, and circles with a dot - in July.
Most migratory birds in the Northern Hemisphere generally move north or south, but their true flyways may deviate 45-60 ° from compass north on spring migrations or south in fall. These deviations are not always explained by the direction of the coastline or river valley. on which the birds fly. In Western Europe, many birds fly in the fall from Scandinavia, England and northern Germany southwest to southern France or Spain. Other birds from the same nesting areas fly southeastward to the Middle East in autumn. Many birds from these two groups stop on the Mediterranean coast, but a similar number of birds of other species fly directly south to Africa. During the annual migrations of hundreds of bird species from Europe to Africa, their desire to fly not directly through the Mediterranean Sea is noticeable, but to go around it from the east or from the west through Spain and the Strait of Gibraltar. On the other hand, many species fly straight across the Mediterranean without deviating anywhere. A good example of the first group of birds flying in a roundabout way is the large, well-known and well-known white stork. In Western Europe, there were thousands of these storks ringed, and their repeated meetings along the entire route of the flight made it possible to quite accurately indicate the path along which they travel (figure below). Approximately the same conclusions can be drawn about the migrations of birds in North America, it is only necessary to "replace" the Mediterranean Sea with the Gulf of Mexico. The biggest difference, perhaps, is that the massive mountain ranges of the western United States and Central America somewhat isolate the birds of the Pacific coast from the inhabitants of the plains of the central United States and the east coast. But there are exceptions here, especially among waterfowl.
Autumn flight of the European white stork... Storks nesting in France and western Germany fly through Spain, while those that nest further east skirting the Mediterranean Sea on the east side.
Many North American bird species from large nesting areas in the eastern and central United States or southern Canada fly more or less southeast to Florida, the Bahamas, or islands in the eastern Caribbean. Some of them fly along this route from the far north. This group also includes sandpipers that nest along the coast of the Arctic Ocean in northern Canada and reach the Atlantic near the mouth of the St. Lawrence River. Many of these waders fly further southeast or south to South America. Wintering of some species is located significantly south of the equator, such as the rice corpse and the American brown-winged plover (picture below). Many migrants do not adhere strictly to any direction during the entire spring or fall flight. Mapping a large number of flyways clearly shows the presence of specific “turning points” located at specific points along the route. For example, the birds of Northern Europe, which bend around the Mediterranean Sea from the southeast or southwest, upon reaching Morocco or Egypt, change direction and fly almost directly to the south.
Migration routes of adult American brown-winged plovers in autumn and spring. Young birds of this species fly to the south approximately along the routes of the spring migrations of adult birds to the north. Thus, they find their way from nesting sites in the Arctic, where they hatched, to wintering sites in South America without the help of adult birds of their own kind.
One of the most difficult periodic phenomena in the life of birds, which consists in the correct resettlement of some birds in the fall, after the hatching of the chicks, to the south and in their equally correct return to the north in the spring, to the nesting sites. In any fauna, birds are distinguished sedentary, that is, living in a given area all year round; flying - arriving in the area only for the withdrawal of children; for the summer (these two categories make up the contingent of birds nesting in the area); migratory - occurring exclusively during their flight in the spring to the north and in the fall - to the south; in winter - who come to the region only in winter; finally, stray - that is, those whose appearance is not annually, wrong, in a word, abnormal. The last three categories are non-breeding birds. There are, however, no sharp boundaries between all the listed categories: they are all connected by intermediate links. So, for example, one and the same species in one area is sedentary or nomadic, in another flying or passing. Most of the sedentary birds, after hatching, begin to move from place to place within a known area (nomadic birds), and in many typical migratory birds these local, so-called summer flights gradually turn into flying away. So, moving from place to place is inherent in birds in high degree... This begs the question: what makes them move? When only typical representatives of the main categories indicated above were taken into account, the disappearance of birds in the fall, with the onset of cold, and their return in the spring, with the onset of warmth, suggested first of all that the reason for the flights was temperature conditions. A proper assessment of the transitional categories in connection with the study of summer movements resulted in modern times almost everyone is convinced that the main incentive to move in general is the lack of special food for each type of food, and that temperature conditions have only an indirect significance - since they determine the lack of food. If the lack of food forces the birds to make local flights in this way, then it is natural to assume that more distant flights are caused by the same condition. If a bird stays in place while it finds the food it needs, and leaves it only when there is a lack of food, then it can be assumed that the movement arose in originally sedentary birds. There are areas on the globe, which nesting birds do not leave after chicks hatch. So, in most of the southern hemisphere, there are no real flights, but there are only phenomena corresponding to our migrations, although the latter occur here on a more grandiose scale. This circumstance should suggest that the P. of birds in the northern hemisphere is due to something that did not exist in some parts of the southern hemisphere. "It is unlikely," says Professor I. A. Allen, "that anything can be considered more accurate than the fact that a moderately warm or subtropical climate prevailed until the end of the Tertiary era throughout almost the North Pole; the climate was previously so uniform everywhere that the need for P. for birds could hardly exist. During the subsequent glaciation of the northern regions, the birds were to be pushed back to the south, where thus the struggle for existence greatly increased. to climatic changes they tried to move somewhat to the north during warmer summer periods, but were again pushed back by the onset of winter.Such movements, at first short and gradual, expanded and intensified as the cold receded to the north and opened up more and more large spaces. " So, P. are cited by Allen in connection with the existence of an ice age in the northern hemisphere. “Suppose,” says Wallace (Nature, V, p. 459), “that a species that has adopted the habit of locomotion can successfully nest in a certain area, but that it cannot find enough food in it during the rest and most of the year.It is clear that those individuals of the species that do not leave the nesting area at a certain time will begin to suffer hardship and eventually die out; the same will happen with those individuals that do not leave the winter feeding areas in due time ... If we further assume that the two named areas once touched, but gradually separated under the influence of geological and climatic changes, then one can understand how the habit of going on a journey at a certain time could become at least hereditary and thus become instinctive. In all likelihood, on the globe there will still be all the transitions from the complete coincidence of the two indicated regions to their complete separation, and the study of bird life will give all the transitions between a sedentary bird, living in one place all year round, and between a typical migratory bird, the nesting area of which completely separated from the wintering area. ”In other words, Wallace believes that the habit of movement necessary to preserve the species gradually developed, strengthened and became hereditary through natural selection.
What drives the birds from the wintering area, where there is undoubtedly an abundance of food? It is possible that some need of the bird remains unsatisfied in the south at a certain time and forces it to undertake a long journey. Indeed, despite recent doubts, the question of the secondary nesting of migratory birds in the winter quarters is now considered to be resolved in a negative sense. On the other hand, thousands of examples can confirm the fact that a bird always strives to nest in the same place at all costs. Let's restrict ourselves to just three examples: in Aivasaks (Finland) the peregrine falcon, Falco peregrinus, nested on the same rock from 1736 to 1855. and, probably, occupies her to this day; Blue Tit, Parus coerulens, nested at Oxbridge from 1785 to 1873. in an earthen vessel placed on a tree; An avdotka, Oedicnemus crepitans, built a nest in Suffolk for many years in the same place, despite the fact that at first it was located on a completely barren area, and then became the center of flowering plantations. So, attachment to the place of homeland can hardly be ignored when considering the reason for the annual return of birds to their nesting sites. It has long been known that during their P., some birds follow certain paths; this is how Sundevall pointed out the paths of the P. crane, Grusgrus. But only in 1874, Professor Palmen was able to prove that most birds fly along paths that are quite definite "geographically", and that there is no P. in the intervals between these main paths. In addition, he found that the flight paths of water birds follow the coastline of the sea, and in those places where the latter fly across the continent, they are located along large rivers. To his work, Palmen enclosed a map, which shows the main routes of passage of water birds in Europe and Asia (see the attached map).
Pelagic and coastal bird paths, along Palmen.
The author distinguishes four main types of paths - 1) oceanic, 2) coastal, 3) marsh and 4) continental - and proves that the respective species of birds pull along each of these main types. The most incomprehensible of the paths allowed by Palmen are oceanic (A, B, X), and of the rest, those with which purely seabirds pull across continents (C, D); at first glance, it also seems strange why birds do not cross the Mediterranean Sea at the closest distances between Europe and Africa. Wallace explains these facts by a different distribution of land and sea in previous geological periods. Oceanic routes formerly ran along the coast of the subsequently severed land; on the contrary, where the path of the sea bird now follows across the continent, there was formerly the sea. These changes were, of course, so gradual that the birds could get used to them little by little, without noticing it. It remains for us to add that each species has its own flight path, so that we must consider the so-called flight paths as the coincidence of the flight paths of several species - the result that Professor Menzbier arrived at when studying the flights of land birds of European Russia (1886). In Central Asia, the late Severtsov (1880) studied the same paths. A very interesting question is how birds find their way during their flights, which often stretch for thousands of miles (North Europe - South Africa about 10,000 miles). Some observers believe that birds are guided along the path exclusively by their excellent eyesight. However, vision can hardly help with travels so common in birds on cloudy and dark nights, as well as those of birds that are carried without stopping, at once over long distances. Palmen, referring to the fact that the majority of migratory birds are young, believes that the journey is guided by the old birds that have already traveled, and, therefore, sees in experience the main factor in the ability to find the way. Despite all the obviousness of this factor, it is nevertheless not the only one, because in most birds it is the young ones that fly off first, and in addition there are species in which the young and old always fly separately, sometimes by different roads; finally, there are species that are always lonely traveling. Wallace attributes this ability to an inherited unconscious habit, and Weismann as "an innate talent for geography." Finally, Middendorf and Newton came probably closest to the truth, analogous to the ability of birds in question to the ability of other animals and many human tribes to navigate through unknown terrain. We do not know how to explain this ability to navigate, but there is no doubt that it exists. If we put it as a basis, then in connection with the remarkably developed memory of the place in birds, with their excellent vision, speed (the falcon of Henry IV flew from Fontainebleau to Malta - 2000 versts - in one day) and flight altitude (according to some calculations, up to 15000 feet), the ability of birds to find their way will not seem too mysterious to us. Let us finish with a few positive data about P. Already Middendorf showed that only in Central Siberia birds pull in the spring (everywhere in the fall) directly from south to north, and that in European Russia their direction is from southwest to northeast, while in Eastern Siberia from the south-east to the north-west. There is evidence that some types of currents also occur in other directions, for example, from east to west and from west to east (in the fall back). However, even in these directions, spring P. always goes to the north, and autumn to the south. We owe Middendorf the proof that birds do not arrive later in all more northerly places than in somewhat more southerly ones. The desire to prove that the arrival of birds is completely dependent on temperature conditions is not confirmed: there are birds arriving and flying away almost day after day, regardless of any weather. Once they have flown in, birds usually prefer to die of hunger and cold rather than return. Males arrive in the spring mostly earlier than females; this is explained by their greater strength and endurance: at a great distance they manage to get ahead of females. There are hints that the farther north a bird nests, the farther south it hibernates. A longer wing (swing of the first category) is characteristic of birds making more distant P. Some birds fly alone, others in families, many stray for this purpose in herds, which may also consist of various species, often belonging to different orders. The so-called exceptional P. of some birds, which do not have any correct periodicity, should be attributed in part to the phenomenon of migrations, in part to what is commonly called the migration of animals (see). Observations of bird P. have been widely organized in Western Europe over the past 20 years. The best case is in Great Britain and North America, in the Mississippi Valley. The 50-year observations of Goetke on Heligoland are also remarkable.
The main literature. Middendorff, "Die Isepiptesen Russlands" (St. Petersburg, 1845); Palm én, "Ueber die Zagstrassen der Vö gel" (Leipzig, 1876); Homeyer, "Die Wanderung der V ö gel" (Leipzig, 1881); Severzoff, "Etude sur le passage des oiseaux dans l" Asie Centrale "(" Bull. Soc. Natur. Moscou ", 1880, pp. 243-287); Menzbier," Die Zugstrassen der V ögel in europäï schen Russland "(ib ., 1886, pp. 291-369); Palm én, "Referat über den Stand der Kentnisse des Vogelzuges" ("Ungar. Comité für den II internation. Orn. Congress", 1891); Gä tke, "Die Vogelwarte Helgolands" (Braunschweig, 1891). Life of animals Encyclopedia of the Third Reich Marine vocabulary Encyclopedic Dictionary of Brockhaus and Euphron Encyclopedic Dictionary of Brockhaus and Euphron Encyclopedic Dictionary of Brockhaus and Euphron Ozhegov's Explanatory Dictionary Ushakov's Explanatory Dictionary Efremova's Explanatory Dictionary Small academic dictionary Russian spelling dictionary Phraseological dictionary of the Russian literary language A large dictionary of Russian sayings Word forms Synonym dictionary 16. Flight to America The huge hall of the airport "Leonardo da Vinci" with glass walls and ceiling was flooded with the welcoming Italian sun. More than a hundred Russians gathered, everyone was bustling, everyone was overwhelmed with joyful anticipation of meeting America. Flight of Birds In time immemorial, all the birds that fly here for the summer did not do this, but lived constantly in the south. But when they felt cramped and hot, they called a meeting and began to say: “We feel cramped, there is not enough food, our eggs are rotting from the heat, the number of children is not FLIGHT I am wintering, late il early, On your seaside shore. At sunset you will see a crimson necklace of footprints in the snow. Waves will rustle like pages, And in the spring, in warmer nights, lonely birds will fly by, Screaming about something familiar. And, with an anxious heart, sensing the Call Great flight The new aircraft, named "Ilya Muromets" -B (C-13B) and serial number 128, was built in the spring of 1914. On May 29, Sikorsky first took it into the air. "Ilya Muromets" -B differed from the first in smaller size and more powerful power plant- four Chapter 15 Flight At the end of October 1972, before the presidential elections in the United States, the OVIR unexpectedly began to call "refuseniks" and give permission to emigrate, and even exempt from tax for education. The so-called "Nixon wave" began. Secret flight of Ju-52 It happened on May 15, 1941. In the middle of the day, a German plane "Junkers-52" unexpectedly appeared in the skies of Moscow and soon made an unauthorized landing on the Khodynskoye field. An unpleasant case. How the U-52 command and services could allow the flight of the USSR border Difficult flight We took off with Junior Lieutenant Sokolov. We sat down first in Armavir, then in Grozny, and in the evening reached the airfield located near Makhachkala. At night the weather turned bad. A cold wind blew from the sea, First flight To overtake XR-4 in the army test center Wright Field decided on their own, by air. For a helicopter with a flight time of only 15 hours, this was a great risk: after all, the flight range was more than a thousand kilometers. But Sikorsky believed in his brainchild. Such Chapter 15 Flight Red beacons were posted along the wide boulevard, roughly 730 meters long, where soldiers were gathered to clear up debris and debris and fill the shell craters. On April 28, 1945 at 3 o'clock, these lights came on, illuminating Flight by plane IMPORTANT! Before you decide to travel by plane, you should make sure that the unborn child will not be harmed by the flight. To do this, you need to consult a doctor and undergo all the necessary examinations. You cannot fly by plane if Flight-grass To fulfill any desires, you need to tame this amazing grass, but this is not so easy to do, because, according to stories, it is transferred from place to place by itself. All of it shines with rainbow colors, and on a dark night in flight it seems like a falling star. Flight At 14:00 all members of the aircraft crew appeared on the runway. Before boarding the planes, the crews of 16 Dakotas talked to the paratroopers. 14:30 - boarding the planes. The silence and order in the cabin were extraordinary. The soldiers sat staring at one point. Flight Two invasion flights into Soviet airspace were planned for April 1960. Powers was assigned a backup for the first flight, which took place on April 9 over a short distance and went smoothly, so Powers hoped that the second, which would make 6. Noah was six hundred years old since the flood of water came to earth. 7. And Noah, and his sons, and his wife, and his sons' wives with him went into the ark from the waters of the flood. 8. And (of clean birds and of unclean birds, and) of clean beasts and of unclean beasts, (and of beasts) and of all the words that creep on the ground lines, clearly visible landforms, a television tower, etc.), turn in the desired direction. In any case / almost all the birds that were taken away from the Mediterranean Sea and Sahara (3600 km) - 108 kcal, These calculations are formal, they do not take into account the possibility of birds choosing strong air currents going in the right direction. But nevertheless, the most distant migrants from small birds, weighing 15 "-30 g, must have energy reserves in the body with a total volume of at least 100 kcal. Fat serves as such a reserve.
"Flight of birds *" in books
16. Flight to America
From the book This Is America the author Golyakhovsky Vladimir
Bird flight
From the book Siberia. Mongolia. China. Tibet [Life-long travel] the author Potanina Alexandra Viktorovna
FLIGHT
From the book One on the Bridge: Poems. Memories. Letters the author Andersen Larissa Nikolaevna
Great flight
From the book Unknown Sikorsky ["God" of helicopters] the author Mikheev Vadim Rostislavovich
Chapter 15 Flight
From the book Journey to the Future and Back the author Belotserkovsky Vadim
Secret flight of U-52
From the book of Meretskov the author Nikolay Velikanov
Chapter II. Takeoff Biography of RD. First flight. Failure. "I am joining a record company." Along the northern route. "Allow me to fly over the Pole to America." Everything on the plane is Soviet! For Chkalov - Gromov. The female crew of the Motherland. Another record!
From the book General Designer Pavel Sukhoi: (Pages of Life) the author Kuzmina Lidia Mikhailovna
Difficult flight
From the book Courage Starts the author Kozhevnikov Anatoly Leonidovich
First flight
From the book Aircraft Designer Igor Sikorsky 1889-1972 the author Katyshev Gennady Ivanovich
Chapter 15 Flight
From the book The Gray Wolf. Flight of Adolf Hitler by Dunsten Simon
Flight by plane
From the book The Main Russian Book of Mom. Pregnancy. Childbirth. Early years the author Fadeeva Valeria Vyacheslavovna
Flight-grass
From the book The book will accept and superstition the author Irina A. Mudrova
Flight
From the book Sinai Debut by Ontario14
Flight
From the book Radio Spying the author Anin Boris Yurievich
6. Noah was six hundred years old since the flood of water came to earth. 7. And Noah, and his sons, and his wife, and his sons' wives with him went into the ark from the waters of the flood. 8. And (of clean birds and of unclean birds, and) of clean beasts and of unclean beasts, (and of beasts) and of all that creep on the earth
From the book Explanatory Bible. Volume 1 the author Lopukhin Alexander
Distinguish between rowing and soaring flights of birds. Soaring is flying on almost motionless wings. By hovering, the bird can go up and down; when descending, she often resorts to sliding. In this case, the bird uses thermal updrafts that arise over an unevenly heated underlying surface, or, as they are usually called, thermals. A light thermal flow over flat terrain or near a slope has a speed of 0.5 to 1.0 m / s; the speeds of soaring birds fit into this amplitude. The higher, the higher the speed of the ascending currents, so the best soars - vultures and condors - climb to a great height.
The term often reaches a height of several thousand meters, its diameter is tens or hundreds of meters. The hovering in circles is explained by the desire of birds not to go beyond the terms that support them. During a soaring flight to a distance, the bird rises in circles within the limits of one term "then plans (glides) to another, rises again to the highest possible height, glides again, etc. Thermals are especially strong under clouds. Sometimes clouds form whole ridges, and then a kind of airway appears in the atmosphere, which soaring birds use. In some places, due to the peculiarities of the orography, the ascending air currents are particularly constant. They, as a rule, have clear flight paths of storks, cranes, daytime birds of prey... Small thermals are formed in forest glades and at forest edges; they are usually used by buzzards for hunting flights over their areas. When a thundercloud moves, air masses rise at a speed of 7-8, and sometimes 10 m / s. This is also used by many birds, in particular seagulls. There are almost no terms in the early morning, so the vultures begin to float after the sun warms up the earth and the updrafts appear.
In addition to the terms, birds use flow streams that occur when moving air masses meet obstacles. On land it can be a house, a forest, hills, especially mountains. In the sea, flow streams arise from a high wave, a steamer, an island. When following the steamer, gulls stay in weak flow rods for several hours without flapping their wings. But the air above the sea surface is more mobile than above the land. The upward and downward currents constantly mix. neck and long narrow wings of an albatross. The latter, when hovering, uses the difference in the speed of movement of air layers. At the surface of the water, the bird is placed between two waves, where the wind is weaker. Then it turns against the wind and ascends to a height of 10-15 m, where it turns sideways and from lateral, or even with tailwind slides almost to the very water, after which it turns against the wind again. The largest wandering albatross has this: the cycle takes 10-11 s.
I
Sometimes birds are caught in downdrafts, the so-called "air pockets", which happens more often with young ones. Birds fall a few tens of meters, often in this case they find themselves in the water, but usually manage to get out of the air hole with an energetic flapping flight.
Rowing flight ¦-¦ is flying with flapping wings. The source of energy here is the muscular strength of the bird, and not the energy of moving air, as in soaring flight. Gliding moments in combination with flapping of the wings are used by many birds, but no special "semi-gliding" or "gliding-rowing" types of flight are allocated, as showed N.A. Gladkov (1949), should not.
Within the flapping, or rowing, flight, vibrational flight (hummingbirds) and wavy flight (woodpeckers) can be distinguished, when flapping alternates with pauses, in which the wings are pressed against the body. Chaffinch and many other passerines fly in the same way. Finally, the term flapping flight is more correct to refer only to the flight of chickens. It is distinguished by its fast and noisy flaps of its wings, its short duration and the ability to give great speed from a standstill. Some types of flight, for example, the flight of a duck, sandpiper, pigeon, falcon, are poorly studied and do not have their own terms. They are still united under the name "rowing flight", although they differ significantly.
The energy of gliding flight is taken from the acceleration of gravity. Usually the bird resorts to gliding flight.
having already a certain forward speed. At the same time, the young loses little both in height and in speed, since the main source of energy is not gravity, but the energy of translational motion, developed by the previous flaps of the wings. The flight of the swift, apparently, is a combination of vibrational flight with sliding. Gliding flight is often called gliding.
The "fluttering" flight - the "hanging" of a bird in the air with the help of fast and appropriately directed flaps of its wings (a kestrel looking out for its prey) - is tiring and limited in time. The hummingbird "hangs" is carried out with completely special movements of the wings and therefore, as already mentioned, stands out in a special vibrational flight. In terms of wing mechanics, it is similar to the flight of insects. Only hummingbirds can fly backwards.
“Takeoff requires the acquisition of the speed necessary for normal flight. Large birds usually throw themselves down. So, the stork falls in the air, sometimes up to 10 m, before picking up desired speed and will make the first flap of its wings. Small birds make one jump into the air, and large birds scatter against the wind. Ducks, especially diving ducks, and also coot do a large run-up on the water. For a swift, taking off from the surface of the earth is difficult, although not possible. A toadstool cannot take off from the ground, only from the water. During takeoff, all birds flap their wings more often and stronger than during steady flight; the amplitude of each swing is also larger.
When landing, the bird reduces its flight speed with its wings, but the carpal parts of the wings continue to do the same work as during fluttering flight - to create a force directed upward. Therefore, the lift does not fall below the minimum allowable value. Just before landing, the widely spaced wings dampen the speed and convert the energy of translational motion into lift: the bird rises somewhat in the air and then quietly descends at the intended point. In many birds, tail and paws are involved in braking.
Figured flight - loops, barrels, descent on the wing, flying upside down - is available to many birds, but is rarely used by them, usually only during mating games.
The flight speeds of birds are high. So, rooks develop a speed of 65 km / h, starlings - 70-80, gray crane and large gulls - 50, finches, siskins - 55, killer whales - 55-60, wild geese- 70-90, waders - an average of 90 km / h. Swifts fly the fastest: the black swift flies at a speed of up to 150 km / h, and the barbed-tailed swift is considered the fastest bird, its speed is 170 km / h.
From the speed with which the bird moves in the air, one should distinguish the daily flight range, which is unexpectedly small even during spring migrations. So, the recorded flight range for storks was 91, 120 and 240 km per day, for the rook - on average 55, for the redstart - 44 km. As a rule, the average daily flight range of birds approximately corresponds to absolute indicators their usual foraging movements at nesting time. And only in special conditions, most often over the sea, birds make long non-stop flights. Thus, the brown-winged plover, during the autumn migrations, overcomes the distance from the Aleutian to the Hawaiian Islands over the Pacific Ocean - about 3000 km. Many birds cross the Gulf of Mexico in a place where it is 1300 km wide. When flying across the Mediterranean Sea, birds fly 600-750 km over the water. About 300 km have to be overcome by quails flying from Crimea to Turkey through the Black Sea in autumn.
A full range of transitional species can be found among birds - from strictly sedentary to correctly migratory. In widespread birds, such transitions are observed within the same species: peregrine falcon, mallard, moorhen. The presence of individuals showing no desire to fly was noted in many species (European robin in Moskva, mallards in the Baltic, many ducks in the headwaters of the Angara, larks in the Turgai hollow, etc.). V Lately sedentary urban populations appear in migratory species (blackbird in European cities, mallard in Moscow ponds, etc.). Thus, bird migration is a forced phenomenon, which in the course of evolution, birds came by following the path of "trial and error". Mistakes were fatal, successful tests led to survival, to the transfer of experience to offspring.
Migrations of birds, although in some cases they repeat the path of dispersal of the species, on the whole correspond well to the modern geographic and ecological situation. They are very dynamic and sometimes change before our eyes. New reservoirs have been created in Turkmenistan - and new wintering grounds and new migratory routes to them have appeared. The regulation of the Nile runoff and the drainage of the Nile delta caused massive flights of Palearctic ducks across the Sahara for wintering in Equatorial Africa.
During flights, birds fly either in a wide front, or use certain ecological channels, which give grounds to speak of flyways. In these cases, birds follow the sea coast or the slope of a mountain ridge, fly along river valleys, over passes, etc. (for example, the Curonian Spit in the Baltic or the Chokpak pass in Talasskiy Alatau). There are also "nodal points" of flyways, in which birds in mass stop to rest and feed, often lingering for a long time.
time to then make the next "throw" to the next * "nodal point". Examples are the deltas of the Volga, Kuban, Amu Darya, some islands (Malta, Helgoland, Barsakelmes) and lakes (Teiiz, Chelkar-Teigiz Balkhash near the mouth of the Ili), island forests (upland oak forests of the Volga region, steppe forests of Kazakhstan, saxaul massifs in Kyzylkum ) etc.
The flight altitude of birds during flights, especially at night, turned out to be much higher than previously thought. Many migratory birds have been recorded over the North Sea at an altitude of 3900 m, and the maximum altitude is 6400 m! At first glance, this phenomenon is difficult to explain, but the height provides the orientation of migratory birds by landmarks. Although the curvature of the Earth limits visibility, it still increases markedly as it rises. So, with clear air, visibility from a height of 100 m is 35.7 km, 1000-113 km, 2000 - 159 km, 3000 m - 195 km.
In addition, at high altitudes, birds can take advantage of strong air currents in the desired directions, including ascending ones. Overcast clouds disorient the birds, they either stop flying, or fly in a randomly chosen direction, and then drift downwind, apparently losing their navigational ability.
During migrations, birds of various systematic and ecological groups have a significant number of "mistakes" - flights. There are many examples of distant and unexpected flights: skuas - at the Rybinsk reservoir and Lake. Teigiz, Tselinograd region, flamingos - near Tomsk and Leningrad, kittiwakes - in Tuva, mountain tap dance - in Moscow region. etc., up to the Australian crane - in Yakutia (in the 80s of the XIX century. It was obtained near Yakutsk, kept in the Zoological Museum of Moscow State University) and hummingbirds - on about. Ratmanov in the Bering Strait.
In a number of cases, flights are undoubtedly caused by storm winds, but a significant number of them are due to the errors of the birds themselves. Overflights, as a rule, end in death, although in individual cases can acquire a regular character and eventually lead to an expansion of the range. This is exactly how, by flying, the ringed mountains-1 person, svrnstele shrike, myna and other birds settled. The eider on the Black Sea has changed from a vagrant to a regularly wintering one and finally nests.
Visits of birds, their numerous mistakes, cast doubt on the absolute nature of their ability to orientate in space. This is a very important, fundamental point. The ability of birds to find their way to nesting or wintering sites is taken a priori. The patterns of bird migrations are probabilistic in nature. Moreover, for
17
thirst for a single individual, the probability of arriving at the desired point is far from one hundred percent. It would be most correct to assume that the number of birds successfully completing their flights ensures annual reproduction in an amount that covers the annual decline. At the same time, the annual mortality rates in migratory birds flying away from a harsh winter to fertile warm lands are by no means less than in birds that remain to winter in harsh northern conditions. In this respect, migratory birds do not gain anything in comparison with sedentary ones, they simply cannot do otherwise, they are forced to fly. And at the slightest opportunity not to fly - they do not fly in mass, they remain. Thus, a bountiful harvest of mountain ash in the unusually harsh winter of 1939/40, when the air temperature in Moscow dropped to -44 ° C, led to a massive wintering of hazel thrushes. Usually, in years with an average and even lower rowan yield, these birds do not stay overwintering, although the temperature conditions are milder. Abundant harvests of birch and alder seeds lead to massive wintering of siskins, etc. Finally, sedentary populations of rooks and starlings have arisen in Moscow, which feed all winter in landfills and near garbage bins. The number of wintering birds of these species grows from year to year and depends little on the severity of winter. In the Baltic States, in places where warm waters are discharged by power plants, about 5 thousand mallards have wintered until recently, according to the latest information, their number has grown to 50 thousand.
"Capture" of birds, especially young ones, by a wave of migrants different types usually not taken into account even when staging experiments with a forced delay. Such experiments were carried out with ducks in the USA, with storks in Europe. Young birds were caught, then they waited until all the birds of this species flew away, then, having ringed them, released them and, finally, having received rings about the places of usual wintering of these species, they believed that the hereditary recording of the flyway was proven. And the fact that the flow of later migrants must have picked up these birds was not taken into account. In nature, cases are common when individuals of other species join a group or flock of birds of one species. This can be observed especially often in autumn, when young birds predominate among migrants. Among waders or river ducks in autumn it is difficult to find a flock of birds of the same species, most often they are mixed.
When gray geese or cranes make regular foraging flights (from places of day or night for feeding and back), each school of birds flies in such a way as to see the flock flying in front. If the front jamb begins to gain height, the next jamb does the same in the same place or a little earlier, etc. Pavotas, prospecting circles, landing — everything is repeated. Thus, a collective system of using space and avoiding danger is taking shape, a system that embraces not only the members of one school, but a significantly “large mass of birds, sometimes up to several thousand.
"V. E. Jacobi, using the method of radar observations, showed that during flights, birds often orient themselves along the flocks in front of them. The distance between flocks can be 50-60 km, that is, the flocks are within the Visibility Range of each other. visually, they survey hundreds of kilometers at once. more height flight and the more numerous the flock, the less often they fly. With low cloud cover and poor visibility, the flocks are few in number, they fly lower and closer to each other. In some species, for example, the Hooded Crow, the flight is a stream of seemingly single birds, but each of them follows its “leader” and watches them, and sometimes even the neighbors. loners fly, then they join in flocks, and even further south - in large flocks. In any case, such a stock can stretch for many hundreds of kilometers. V. E. Jacobi suggests that this is how passerines and birds migrate over the sea. take the direction, obviously, on the shore, and then fly without turning, it is clear that the first flock, which took the right direction, can be followed for a long time by more and more flocks of different species. Such a relay race can continue at night. closer to the truth than the assertion that birds amend the position of the salt, using a special "internal clock", and moreover, they orient themselves according to the Polar star. experiments, however, quite contradictory, this was shown), but "mobile landmarks" in the form of flocks flying in front, apparently, are much more important.
Landmarks are no less important * - river valleys, mountain ranges, lakes, and in some cases even separate, well: noticeable buildings, towers, high-rise buildings, etc. Thus, carrier pigeons of the Ostankino biological station of Moscow State University during training invariably focused on the dome of the main pavilion VDNKh and only from it turned to their dovecote.
The ability of a bird to return to its nest from any significant distance is called homing (from the English home - house). Experiments with different bird species have yielded conflicting results. It is only clear that the return to the nest is of the same probabilistic nature, as well as getting to the wintering area or to the nesting area during flights. In an unfamiliar area immediately after departure by
ilpim * - -
It took much longer to return to them than it took to fly in a straight line. Naturally, the time of return was always directly proportional to the distance the bird was taken away. Finally, during mass experiments with swallows and other birds, it was found that the percentage of birds that did not return at all was quite large. The same is observed when training carrier pigeons over long distances: the percentage of returns and their speed quickly decrease with increasing distance.
For orientation of birds during migrations, their traveling migrations, during which they get acquainted with the territory, are of significant importance. The works of Ya. A. Vnksne proved that the choice of a future nesting site by young black-headed gulls is largely determined by their acquaintance with the water bodies obtained during their nesting migrations. These observations reveal one of the reasons for the frequent violation by birds of the so-called "nesting conservatism", that is, the obligatory return for nesting to the place of their birth. On the other hand, they leave no doubt that the visual memory in birds is excellently developed.
For the first time, the energy consumption during flights was accurately established in experiments on the Curonian Spit. Large traps were built at a distance of 50 km from each other. The difference in the average level of energy reserves for the ptnc that fell into the first and second traps was the energy consumption per 50 km of flight. It turned out that finches spend -3.8 times more energy on flight than “existence”, yurok and siskin - 2.5 times more. If we take into account the deliberately underestimated indicators of the energy of the existence of birds in the cages, then the difference between the expenditure of energy during "normal" life and on flights will be even smaller.
VR Dolnik and his co-workers found that long-distance migrants with an economical flight spend about 3 kcal per 100 km of flight. If we take these numbers as a basis, then the energy costs will be approximately equal:
Gulf of Mexico Baltic Sea Black Sea
(3500 km) - 105 kcal, (300 km) - 9 kcal, (500 km) - 15 kcal.
Fat has a caloric content of 9.5 kcal / g, while the calorie content of carbohydrates (glycogen) formed in the body is more than two times lower - 4.2 kcal / g. When fat is burned during work, a certain amount of water is released (the so-called metabolic water); while the bird is using fat, it almost does not need water. The path of fat oxidation in poultry tissues is shorter than when using carbohydrates as an energy source, which is very important at a high metabolic rate. Finally, oxidation of carbohydrates produces lactic acid, one of the main sources of muscle fatigue. When fat is oxidized, lactic acid is not formed, therefore, in migratory birds during migration, VNR displaces glycogen from its main stores - the liver and pectoral muscles. This provides significant gains. About half of the required amount of fat is stored in the muscles of the liver and abdomen. The other half is deposited directly under the skin of the birds; at first, subcutaneous fat is deposited only on the pterilia, and then on the apterias. Many waders, for example, have a thick layer of fat that shows through under their thin skin. The mass of birds during migrations is 20-40% more than usual due to fat. To provide itself with energy of 100 kcal for a long-distance flight (about 3000 km), the bird must store about 11 g of fat.
Usually the maximum amount of "fat is necessary costs to make the next "throw" during the flight. The accumulation of fat in small birds (under favorable nutritional conditions) proceeds at a rate of 0.1–0.5 g / day. Therefore, the "set" of migratory fat takes at least 10-15 days (taking into account that it starts not from zero, but from some previously reached level). The amount of food consumed increases sharply, hyperphagia, or overeating is observed. In the non-migration period, even with an abundance of food, hyperphagia and powerful fat deposits do not exist. This is not the case with sedentary birds, which never get so fat as migratory ones.
When fat reserves are depleted, migration is interrupted and increased feeding begins. In some cases, small birds can accumulate more than 1 g of fat per day, and in a cage, an emaciated bird gains up to 2 or even 5 g of fat per day!
Fat reserves are essential for a normal flight.
During the autumn flight of quails in the Crimea, first fly * according to EP Spangenberg, almost exclusively adult males with an abundant supply of fat; their mass reaches 146 g. Later, females gradually begin to predominate among passing birds, and then fry of both sexes, possessing a rather significant amount of fat, are increasingly found. When the mass flight of quails is over, on the southern coast “late juveniles weighing no more than 75 g appear, which, apparently, do not fly further, but partly die in winter bad weather, partly survive the winter safely. Such young birds never form flocks and outbursts, but singly (they are distributed over the area of the southern coast "(Spagenberg, 1948, p. 89).
An abundance of oxygen is required to successfully oxidize a significant amount of fat in flight. Here you should pay attention to the peculiarities of the respiratory system of birds, which supplies the body with oxygen. The lungs of birds are small and occupy a small part of the ore cavity. The extensibility of avian lungs is very low, especially when compared to the lungs of mammals. Moreover, if in a flightless bird the respiration mechanism is reduced to the approach and removal of the breast from the spine due to the work of the intercostal muscles and the movement of the ribs, then in flight this mechanism is turned off, the ribs are made motionless. But another remarkable mechanism is triggered - "double breathing". Air bags come into play.
In addition to the auxiliary nasopharyngeal system of air sacs associated with the pneumatization of some bones of the skull, birds have a complex and huge system of pulmonary sacs in comparison with the lungs. They depart from the branches of the bronchi and, in contrast to the lungs, are extensible. To the blood vessels passing in the steaks of the air sacs are not connected with the circulatory system of the lungs, so it is impossible to count the air sacs as respiratory organs in the literal sense. At the same time, their role in the respiration of birds is great.
There are two pairs of the largest air sacs - chest and abdominal, in front of them are three more pairs of smaller bags. In total, the air sacs fill the entire body of the bird, their branches penetrate the bones, muscles, spine; in some birds, branches of the air sacs lie between the skin and the muscles. Air sacs play a critical role in lung ventilation. When inhaling, oxygen-rich air fills not only the lungs, but also the air sacs. When you exhale, the air from the bags is blown through the lungs again and gives them its oxygen. The muscles that control the movement of the wing are especially important: "they press on the front bags, blowing the air through the lungs." This is how the "double" breathing of birds occurs, in which the assimilation of oxygen by the body occurs during inhalation and exhalation. Hence the high intensity of oxidative processes in birds. The place of exchange of gases is not only the lungs, but also the pneumatic cavities of the bones, covered with epithelium and rich in capillaries. In addition, the hemoglobin of the blood of birds easily gives up oxygen, therefore, the release of oxygen by capillary vessels in the tissue of the body is very intense. This is the reason for the high constant body temperature of birds and an energetic metabolism. The number of breaths in small birds is very high: in passerines - about 90-100 times per minute, in hummingbirds even 108-146 times (according to other sources - 180 times), while in a kite - 18, in a condor - 6, in an emu - 2-3 breaths per minute. With anxiety, the number of breaths and heartbeats of the bird increases sharply.
Thanks to the system of air bags and "double" breathing, the faster the bird flaps its wings in flight, the better and more completely the air in its lungs is replaced. Therefore, dyspnea during rapid flying movements in birds does not occur. Air bags have other important functions as well. Evaporation occurs from their inner surfaces, which is especially important for dry, glandless skin. Thus, the success of thermoregulation, in particular the protection of the most important organs of the body (heart, lungs, intestines, gonads, etc.) from overheating, is largely determined by the work of the air sacs. In cold weather, the bags help keep you warm. In addition, the air sacs reduce the space between the internal organs of the bird, facilitate the change in their shape and volume when the goiter and esophagus are filled. When thrown into the water, air sacs weaken the shock experienced by the body, and under water they can repeatedly drive the same volume of air through the lungs, until the oxygen is fully released, thereby prolonging the time the bird is under water. In addition, in water and on water, air sacs help to regulate the specific gravity of the bird. Finally, in some birds, the air sacs inflate when poked (frigate) or act as resonators.
The energy of the flight is also provided by adaptations to it. circulatory system birds: they have completely separated arterial blood from venous blood, the heart is four-chambered and relatively large. Especially large hearts in well-flying birds. With an approximately equal mass of the birds themselves, the heart of the hobbyist is 1.7% of the total body weight, in the kestrel - 1.19, and in the magpie - only 0.934%. The largest relative heart mass in the smallest birds: in the ratchet stump - 1.829%, and in the hummingbird - 2.4-2.85%! The increased intensity of blood circulation is associated with a large loss of heat in V small birds, which have an “unfavorable” ratio of the volume of the body and its surface. Thus, the loss of heat per kilogram of mass per hour for a duck is 6 kcal, for a pigeon - 10 and for a sparrow - 35. The relative heart mass also increases in northern and mountain subspecies.
An energetic metabolism is also due to a high heart rate; in small birds, the heart rate is noticeably higher than in large ones. The heart of a sparrow beats 460 = once a minute, for a jackdaw - 342, for a kayuk - 301, for a mallard - 317, for a turkey - 93, for an ostrich - 140 times. These figures are approximate; at rest, the heart beats almost twice as slow as when moving quickly. In different individuals, the variations can also be large: in domestic chickens - 140-390 heartbeats per minute, in pigeons - 136 - 360, in greenfinch - 703-848, in goldfinch - 914-925. In a hummingbird, at rest, the pulse reaches 500 beats per minute, in flight - up to 1200 beats at 600 breaths amp; minute. True, during nighttime torpor and a decrease in body temperature to 15-20 ° C (according to some reports, even up to 10-12 °), the pulse of a hummingbird drops to 100-50 beats per minute. Thus, the tension of blood circulation in birds corresponds well to the large expenditure of energy during the flight.
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