The term "migration" comes from the Latin word "migratus", which means "to change". This word has a special meaning when it refers to . Migration is the movement of animals from one region (or) to another. It occurs during certain periods of time or seasons of the year. Animals migrate to breed, grow, seek food, or avoid cold weather. For many, migration occurs twice a year. They leave in autumn and return again in spring.
What makes a bird a bird?
All kinds of birds have feathers. There are other characteristics common to the class of birds, but feathers are the only feature that is completely unique to these animals. Many people might say that flying is what makes birds special, but did you know that not all birds fly? Emus, cassowaries, and rhea are non-flying birds. Flightless birds such as penguins are excellent swimmers underwater.
Birds have many interesting adaptations that allow them to fly. Light but strong bones and beaks are adaptations for weight reduction during flight. Birds have unique eyes, ears, legs, and can also build nests. Some species are capable of making beautiful sounds.
Why do birds migrate?
Many birds seek places where it is warm, there is an abundance of food, and the opportunity to breed and defend themselves from predators. In, especially in, the climate is quite warm, so birds can find enough food throughout the year. Steady daylight gives them plenty of time to eat every day, so they don't have to fly off to find food.
How do birds navigate?
Navigation is difficult because it requires birds to understand three things: their current location, their destination, and the direction they must follow to get to their destination.
Some birds use the sun and stars to navigate. Others navigate by features such as rivers, mountains, or coastlines. Some birds can even use their sense of smell. Although birds are also able to move on cloudy days and fly through where there are no clear guidelines. So how do they do it?
Scientists have come to the conclusion that birds feel the Earth's magnetic field through magnetoreception. In the beaks of birds is the so-called magnetite - this is an iron-containing mineral that acts as a compass. Other scientists believe that birds can see the magnetic field with their own eyes. Science does not yet know everything about bird orientation, but it is likely that they use several methods of navigation.
Why do birds fly in a wedge?
A flock of birds flies like a wedge for a reason. Large birds such as geese and ducks form a wedge to reduce air resistance. The wedge allows flocking birds to fly farther and more efficiently than birds flying alone.
When flying in a wedge, efficiency is increased by 70%. The lead bird and the trailing bird have the hardest time, while the birds in between benefit from the flapping of other birds' wings.
In addition to improving flight, this method is also useful for communication between birds. Wedge flying allows birds to fly close to each other, as well as to hear and see their relatives. They communicate information to each other (through sounds) and can stick together.
The danger of migration
Sometimes birds must fly through harsh habitats such as deserts where there is little water or oceans where there is no place to rest or feed.
Even if they find food and water, the birds need to land on the ground where they risk becoming prey.
There can be many predators along the migration path. Depending on their size, migrating birds become prey for foxes, wolves, humans, and other animals. Some birds may be attacked by larger bird species while in flight. Sometimes difficult weather conditions make it difficult to fly and even lead to death. It happens that birds collide with aircraft, which is dangerous both for themselves and for aircraft.
How do ornithologists study birds and their migration?
Bird ringing is one of the methods used to study them. Scientists place a small, individually numbered metal or plastic ring around a bird's foot or wing. They also use special nets known as mystic nets as a way to capture wild birds for research.
In this way, ornithologists can capture the same bird multiple times, measure and weigh it, and collect another important information for a long time. Sometimes scientists use satellite data to track bird migration routes.
Fascinating Facts
- The Arctic tern has the longest known migration route. It flies about 70,000 km per year between breeding grounds in the Arctic and winter ranges in.
- Birds can fly at speeds of 30 to 80 km/h.
- Large birds fly faster than smaller species.
- For 10 hours of flight, some birds cover about 650 km.
- Radar studies show that most flights occur at altitudes less than 3 km, but some birds have been recorded at altitudes above 8 km.
- Birds that fly long distances fly at a higher altitude than those that fly short distances.
winged wanderers
Dates of arrival and departure of birds
Arrival and departure times various kinds birds have not only cognitive, but also some practical interest. This is especially true for the arrival time. The timing of field work depends on the course of spring, and in many respects the fate of the crop. There are many signs among the people that predict the weather in spring and summer. Many of them are associated with birds. In the course of spring events in the life of birds, one can determine the rate of snow melting, plowing and sowing conditions, fodder yields, and much more. The friendly passage of birds speaks of the upcoming friendly spring; flight of flocks at high altitude - about the upcoming abundant flood; early arrival of cranes - about a friendly disputed spring; larks - about a warm spring. It was believed that if waterfowl arrived fat, not emaciated, the spring would be cold and long.
The arrival of some common bird species determined the start of many agricultural activities more accurately than calendar dates. For example, rooks flew in - it's time for gardeners to repair greenhouses, prepare seeds; larks appeared - get the beehives. Forty days after the arrival of starlings, they began to sow buckwheat, and with the advent of lapwings, turnip seeds were selected for sowing. After the arrival of swifts at the end of May, it was supposed to sow flax. The return of the birds was a sign of important changes in nature for the farmer. The arrival of larks meant the beginning of clearing the fields of snow, the appearance of numerous thawed patches. It coincided with the annunciation (April 7), when it was supposed to release birds from cages and bake "larks". After the arrival of finches, a slight cooling usually sets in. With the arrival of wagtails, rivers open up. The appearance of gulls means the imminent end of the ice drift, and the return of flocks of lapwings is associated with the beginning of a heavy flood.
The well-known Russian phenologist and naturalist D.N. Kaigorodov at the beginning of our century organized a whole network of correspondent-observers who collected data on the course of the spring arrival of common known bird species of the forest belt of Russia. Based on the analysis and generalization of more than 25 thousand observations, he marked on the map the places of the simultaneous appearance of rooks, storks, cuckoos and other birds in spring. The lines connecting these places - isochrones - show the features of the course of the spring migration, its speed, direction, connection with changes in air temperature and other meteorological conditions. For example, rooks return to all nesting sites in the European part of the USSR in just 5 weeks. They move from southwest to northeast at an average speed of 55 km per day. The cuckoo flies about 80 km per day, the white stork - 60 km. The more observations that form the basis of such calculations, the more accurate they will be. Unfortunately, the number of volunteer correspondents supplying accurate phenological data to ornithologists has now declined sharply. But they could bring invaluable benefits to both ornithologists and specialists. Agriculture, to provide significant practical assistance in assessing changes in the natural conditions of large areas over a number of years, in predicting the timing of sowing and harvesting in different areas, etc. The school calendar of nature is a continuation and development of the folk calendar, which still helps farmers in the fight for the harvest. In the 1920s, the bird arrival calendar was carefully kept at the Biological Station for Young Naturalists in Sokolniki (Moscow) and transferred to the Agrometeorological Service Department of the USSR Ministry of Agriculture.
Information about the onset of various seasonal phenomena in nature, including the arrival and departure of mass bird species, received from institutions and individual correspondents, is regularly published by Hydrometeoizdat for periods of 10-12 years.
Each specific year, the dates of arrival of birds differ slightly from the long-term average: some are more, others are less. We can recommend a task for members of the biological circle: to trace when they first met this or that bird in the year, and compare this number with the average arrival date indicated in the table, and then think about how it can explain the shift. The arrival usually comes in several "waves", and between them there are periods of relative calm.
| arrival wave | bird species | Date of arrival (multi-year average) | Signs of spring or type of agricultural work |
| I | Rook | 18-19.III | Preparatory work |
| II | Starling | 30.III | Preparatory work |
| Finch | 30.III | short-term cooling | |
| lark | 1.IV | The appearance of thawed patches in the fields | |
| III | white wagtail | 5.IV | Beginning of ice drift |
| Lapwing | 5-7.IV | Preparing seeds for the garden | |
| Black-headed gull | 8.IV | End of ice drift | |
| Robin | 8.IV | End of ice drift | |
| IV | Redstart | 17.IV | |
| mallard duck | 18.IV | ||
| Crane gray | 18.IV | ||
| Chiffchaff | 18.IV | ||
| Pied flycatcher | 19.IV | Start of plowing | |
| V | Cuckoo | 27-30.IV | Noticeable warming |
| Ratchet warbler | 27-30.IV | Start of sowing vegetables (carrots, beets) | |
| Willow warbler | 27-30.IV | ||
| Wryneck | 29.IV | ||
| killer whale | 30.IV | sowing | |
| VI | Warbler-chernogolovka | 5.V | The height of the sowing season |
| gray flycatcher | 8.V | The height of the sowing season | |
| Nightingale | 8-10.V | The height of the sowing season | |
| mocking | 11.V | The height of the sowing season | |
| VII | Oriole | 16.V | Planting cucumbers, cabbage, peas |
| Shrike Shrike | 21.V | Sowing barley and flax | |
| Lentils | 21.V | Sowing barley and flax | |
| Landrail | 21.V | Sowing barley and flax | |
| Quail | 21.V | Sowing barley and flax | |
| swift | 21.V | Sowing barley and flax |
Observations of the passage of birds can be carried out at any point in the middle lane, but it is better on one of the small or large flyways - on the coast of a reservoir, a strip of forest among open spaces, in a valley, at the edge of a forest. You can observe the flight just on the outskirts of the city, and in the midst of it - from the window of a multi-storey building. It would be nice to have binoculars, at least theatrical ones. At a certain hour (preferably early in the morning) for several days in a row it is interesting to count how many and which birds were seen flying by. Such observations make it possible to follow the dynamics of the migration of several species (beginning, peak, end), the change of some birds during the migration by others, and the general end of an intensive migration. Of course, one must observe daily, patiently and at the same time be able to distinguish at a distance ordinary species birds (Fig. 13).
Rice. 13. Silhouettes of birds in flight (according to Sungurov, 1960):1 - swift; 2- barn swallow; 3 - seagull; 4 - sparrow; 5 - crested lark: 6 - wagtail; 7 - bee-eater; 8 - starling; 9 - thrush; 10 - owl; 11 - sparrowhawk; 12 - partridge; 13 - jackdaw; 14 - pheasant; 15 - large curlew; 16 - rook; 17 - city swallow; 18 - snipe; 19 - kestrel; 20 - forty; 21 - lapwing; 22 - woodcock.
The analysis of the sequence of passage during the migration of adult and young birds in different groups passerines. Three main types of migration have been identified: in the first, adult birds fly away before young ones; second, both age groups start migrating at the same time, but adults generally migrate faster; the third - before departure, the birds stray into large flocks and fly together throughout the entire route.
Introduction
Currently, most authors point out that during migration, adult birds cover the distance to wintering grounds much faster than juveniles. This is typical for different species, both granivorous, for example: finch Fringilla coelebs, common lentil Carpodacus erythrinus, and insectivorous: nightingale cricket Locustella luscinioides, river cricket Locustella fluviatilis, marsh warbler Acrocephalus palustris, reed warbler Acrocephalus scirpaceus, kamy badger Acrocephalus schoenobaenus, thrush warbler Acrocephalus arundinaceus, bluethroat Luscinia svecica.
The aim of the work was to compare the sequence of passage of juveniles and adults of various groups of passerines at the biological station of the KemSU "Azhendarovo" and to compare our data with the literature, which determined the choice of research objects.
Material and methods
The work is based on the results of captures of small passerine birds in the Krapivinsky district of the Kemerovo region at the biological station of the KemGU "Azhendarovo" (54o45` N; 87o02` E) in 2011. A total of 13091 individuals were caught during this time, of which 108 were song crickets Locustella certhiola; 2668 – garden warblers Acrocephalus dumetorum; 289 – common nightingales Luscinia luscinia; 414 – rubythroat Luscinia calliope; 242 - Bluethroat Luscinia svecica; 381 - finch Fringilla coelebs; 266 – finches Fringilla montifringilla; 402 - common lentils Carpodacus erythrinus; 23 - oatmeal crumbs Emberiza pusilla; 53 - Reed Buntings Emberiza schoeniclus. The trapping of birds was carried out with spider nets installed in willow thickets used by birds as migration corridors, on the banks of the river. Tom and its left tributary. Azhendarka, as well as on the adjacent nettle heath used by birds as a feeding station. Networks were checked at least once every 2 hours from dawn to dusk.
An important feature of the biological station "Azhendarovo" is its location. Most migratory birds fly along large rivers; in our region, this role is played by the river. Ob, therefore, in the middle course of the river. Tomsk, we record only the passage of local nesting birds, almost without the background of northern populations, which allows us to more clearly trace the initial stages of migration.
Main part
Studies at the biological station of the KemSU "Azhendarovo" have shown that in a number of species, adults and young individuals begin to behave differently already at the initial stages of migration. Based on the conducted research and analysis of the literature, three main types of migrations were distinguished, differing in the sequence of passage of both adults and juveniles.
The most prominent representatives of the first type of migration from insectivores is the garden warbler, from granivorous - common lentil. The garden warbler breeds one brood per season, and immediately after the emergence of the young, adult birds leave the nesting area (Fig. 1) without stopping. At the same time, they molt in the intermediate part of the range or in wintering areas.
According to the data of repeated captures of ringed birds at the biological station, several stages can be conventionally distinguished during migration. After the end of the nesting period, post-nesting migrations begin, which turn into mass migration. A similar behavior in the garden warbler is described by A.S. Malchevsky in the Leningrad region, and, according to our data, the first wave is formed by adults, and only then young ones fly.
Most garden warblers caught during the nesting period cease to be recorded by the beginning of the mass migration, only a few individuals are re-caught after the peak of the migration, after which mainly “transit” or possibly late-appearing young are recorded. At the end of the migration, a long trail of late-flying juveniles is recorded. Similar behavior is noted by N.S. Cherentsov near the badger warbler, reed warbler and marsh warbler on the Curonian Spit (Kaliningrad region) and V.M. Chernyshov - at the badger warbler and the Indian warbler Acrocephalus agricola on the lake. Maly Chan (Novosibirsk region), he also notes that the badger warbler, like the garden warbler, does not molt before migration.
In addition to warblers, a similar pattern of movements during autumn migrations is also characteristic of some granivorous - common lentils.
This species, like the garden warbler, hatches chicks only once per season and does not molt in breeding areas. During the departure of birds, two peaks can be distinguished, the first is formed mainly from adults, less often mixed; in the second, the absolute majority of departing birds are underyearlings, and a trail of late-flying young individuals is also formed (Fig. 2). Studies at the Chokpak Pass (Kazakhstan) show that adults are the first to appear, with time their proportion decreases, and the proportion of young birds increases.
Nightingales can be attributed to the second type of migration. Of these, the most widespread at the biological station are: the common nightingale, the red-throated nightingale bluethroat. In our region, these species, under favorable conditions, are capable of two clutches per season. In the vicinity of the station, they are common nesting species; the common and rubythroat nightingales are recorded throughout the summer.
Departure of adults and juveniles usually coincides (Fig. 3), however, in the process of migration, disunity between adults and juveniles increases. Adults of the common nightingale disappear from net captures after the end of the nesting period and reappear already during the mass migration (which is confirmed by repeated captures more than a month later). A similar picture is also observed in the rubythroat, with the only difference that it did not record repeated captures of adults during migration ringed during nesting. Although bluethroat nests in the vicinity of the biological station, it is rare in net trappings during the nesting period and is recorded mainly on migration; the departure of adult birds is completed before the mass migration of young birds (Fig. 4).
Juveniles use a wider range of habitats than adults, which is interpreted as evidence that their ability to correctly choose a biotope is less perfect than that of adults, so they are constantly recorded in different biotopes. I.N. Panov, using bluethroat as an example, notes that young birds accumulate fat very slowly, after each night throw they stop for 4–5 days, while adults, although they stop for about the same period, but as a result of more efficient fat accumulation, they can make several night throws in a row, with stops between them for only one day. As a result, the speed of movement of adult birds is much higher than that of young ones.
This is confirmed by data based on the analysis of finds of ringed birds in wintering areas, where in autumn adult bluethroats are found much earlier than young ones.
The third type of migration is characteristic of late departing granivorous species. Of these, two closely related species are the most widespread at the biological station: the chaffinch and the finches. Before departure, both of these species make post-nesting migrations, during which they stray into large flocks, where both adults and juveniles are present (Fig. 5).
Mass departure, as a rule, takes place in a rather short period, after which a trail of late-flying individuals is almost never recorded or it is rather small. In the Chokpak Pass (Kazakhstan), adult and young finches appear simultaneously, and the relative number of adult birds increases towards the end of migration; however, V.A. Paevsky writes that in Europe, among finches, adult birds migrate faster than young ones.
Finches on the territory of the biological station are recorded only during their migration; no differences in the timing of migration between adults and juveniles were found (Fig. 6).
There is also a scenario where adults and young people fly the entire route together for long-distance migrants.
Buntings that mainly nest north of the Kemerovo region and are recorded only on migration, for example: baby bunting, reed bunting, juveniles and adults are always caught together (Fig. 7), and adults, as a rule, are recorded at the peak of migration, and not before / after the emergence of young. Studies of the migration of the reed bunting in the Chokpak Pass (Kazakhstan) show that adults and juveniles migrate simultaneously, however, the middle period of migration of underyearlings falls on the third five-day period of October, and adults - on the fourth.
Conclusion
As shown by our observations and analysis of literary sources, it is possible to distinguish 3 main types of bird migration ratio different ages during autumn migration. The first type corresponds to species in which adults fly away for wintering immediately after the nesting period, and only then do young ones start. Such species, as a rule, nest only once per season, many of them molt in wintering areas or in the intermediate part of the range, they do not form large flocks. In addition to the described warblers and common lentils, the song cricket also belongs to this type. Probably other crickets behave in a similar way. According to the second type, birds fly that try to produce several broods per season, however, they also do not form large flocks, although they often start at the same time or with slight differences in timing between young and adults; in the process of autumn migration, adults generally migrate faster due to greater experience. The third type includes species that, as a rule, nest at least twice a season, and before departure they gather in large flocks that start at the same time, and after them a train of late-flying birds is not formed or it is rather small, usually these are the latest flying granivorous species.
The change in the type of migration of birds of different ages reflects the development of the adaptation of long-distance migrants to maintain population stability, which is expressed first in an increase in fecundity during the nesting period, and then in joint flights of adults and juveniles, which reduce the mortality of young inexperienced individuals during autumn migration.
A. V. Kovalevsky, V. B. Ilyashenko
Source
Bulletin of the KemGU No. 3 (51) 2012
When the cold season comes in Russia, many birds fly away for wintering to warmer climes. The main reasons for this are that it gets too cold and there is no food.
In general, bird migration occurs in the period from late August to mid-November. Each bird species has its own terms of departure to warmer climes.
When Birds Fly: Migration Timing
- At the end of August in Russia it is already getting colder for cuckoos - they are the first to leave our region.
- Swifts and swallows are next in line. They usually fly away in the very first days of September.
- In early September, thrushes, finches, wagtails, starlings also fly away. They prefer to experience the winter in Italy, Spain and Portugal. Ducks, cranes, and waders, also flying away during this period, live near the Nile; hoopoes, flycatchers, corncrakes and great snipes go to Africa; snipes prefer Transcaucasia.
- Mid-September is the departure time for mallard ducks. They like the south of the Caspian, the Black, Azov and Mediterranean seas, Transcaucasia, Iran and the British Isles.
- Geese begin to leave their homeland in mid-September, but a massive migration occurs at the end of this month. They like to spend the winter in the Crimea, on the Sivash and the Caspian.
The flight of birds to warmer climes is a gradual process, the timing is always determined approximately. Birds migrate in flocks, often roam, as the path is long and many obstacles must be overcome. For landmarks, birds use large geographic features: mountains, rivers, coasts of the seas, etc.
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