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Birds foraging for food

The ability to obtain food plays a leading role in the life of birds. The nature of nutrition influences all the main aspects of the life of birds: distribution, association with habitats, daily and seasonal rhythm and reproduction. Due to their warm-blooded nature, neither humidity, nor temperature, nor other abiotic factors limit the distribution of birds. They are found everywhere where food can be found, from the North Pole to the South, where even mammals do not go. The connection between distribution and feeding patterns is most easily seen in specialized forms. Thus, the vulture eagle (Gipohierax angolensis) feeds on the fruits of the oil palm Elae guineensis and is distributed in Africa only in those areas where this palm is found. The arama crane (Aramus guarauna) in Florida is found where the Pomacea snail, the bird's main food, is often found. Crossbills are distributed only in those places where they can get the cones of coniferous trees, etc.

Birds are distinguished not only by a wide variety of food consumed, but also by obtaining it in different places, at different times of the day, in different ways. The initial type of nutrition for terrestrial vertebrates - feeding on invertebrates - is also widespread among birds. The most numerous of invertebrates - insects - are of greatest importance as food items. Among the birds there are many insectivores. This is the majority of the phylogenetically youngest, widespread and diverse (3/5 of all bird species) order of passerines, as well as relatively close to them woodpeckers, swiftlets, cuckoos, nightjars and many Coraciiformes.

However, different species, similar in the nature of food, obtain it in different territories. Among them there are inhabitants of the tundra, taiga, various types of forests and steppes, savannas, deserts and various mountain zones. Even species living nearby share foraging sites among themselves. For example, among the birds inhabiting the temperate zone of the forest belt, there are species that feed mainly on the ground, for example, starlings, blackbirds, forest pipits, etc. Various species of warblers forage in the shrub layer. Many forest birds feed in trees, specializing in collecting prey in different parts of them. Woodpeckers are widely known for their chiseling ability, extracting adult insects, as well as their larvae and pupae hiding under the bark in the wood. The nuthatch collects insects from the surface of trunks and thick branches. The common pika hunts in a unique way, with a very strongly curved thin beak. Methodically examining tree by tree, each time she lands at the base of the trunk and, moving in a spiral, moves up to the first branches, and then, without rising higher, flies to the base of the next tree. Moving along the trunk, the pika uses its specialized beak to extract insects from the thinnest cracks in the bark. Different types of tits rule in the crown of a tree, completely searching the branches, including their thinnest ends, on which they freely hang down with their backs and, swaying, feed. Tits are also distinguished by the fact that they also take stationary prey: insect eggs and pupae, which is not available to all species. Different types of warblers collect insects, mainly aphids, from leaves and ends of branches, while they move not only along the branches, but also, when flying up to the crown of a tree, they stay near it in the air in one place with the help of a fluttering flight, reminiscent of the flight of a butterfly. Hunting flycatchers sit in trees, but grab insects moving past them in the air. Living not only in forests, but also in a variety of other landscapes, swallows and swifts hunt for insects in the air, flying tirelessly with their beaks wide open. Some swallows retain the ability to peck insects from trees. This is completely inaccessible for swifts. Just like swallows and swifts, sandpipers that live in dry open spaces also hunt. The same method of catching prey is used by nightjars that hunt in open spaces in a variety of habitats, but unlike others, they hunt at night.

A similar pattern of distribution of hunting sites and methods of obtaining food can be observed among birds inhabiting other areas of the globe. For example, pittas (Pittidae), birds of the tropics and subtropics of the Old World (Timaliidae), and hoopoes (Upupidae) living in Eurasia and Africa feed on the ground. In the shrub layer of the South American tropical forest, todies (Todidae) and some species of the family of American warblers (Mniotiltidae) feed. Like woodpeckers, barnacles (Cepitonidae), common in tropical forests all over the world, extract insects and their larvae from under bark or wood. Like pikas, wood hoopoes (Poeniculidae) of tropical Africa, poison dart frogs (Dentrocolaptidae) inhabiting the tropical forests of Central and South America, and one of the American warblers (Comsothlypis) climb the trunk, leaning on their tail, and remove prey from thin cracks in the bark. Manakins (Pipridae) living in the forests of South and Central America have the habits of tits. Vireos (Vireonnidae) in the tropical forests of South America, like warblers, carefully examine the leaves and branches of trees, and white-eyes (Zosteropidae) behave in a similar way in the forests of the tropics and subtropics of the Old World. Like flycatchers, tyrants (Tyrannidae), jacamaras (Galbulae) and sloths (Buceoniidae) hunt in the tropical forests of North and South America, as well as drongos (Dicruridae), inhabiting the tropics and subtropics of the Old World, and trogons (Trogones), found in the tropics of the Old and New World. Some antbirds (Formicariidae), common in Central and South America, have a unique method of hunting. They follow wandering ants for many days and peck at the insects scared away by them. Egyptian herons (Bubulcusibis) feed mainly on insects disturbed by grazing livestock, and collect flies directly from the animals themselves. In all seasons, small flocks (6-8 birds) of buffalo birds (Textor) accompany large domestic or wild animals everywhere. Buffalo birds collect food on the backs of animals, catching blood-sucking insects and sucking ticks.

Among birds in different orders, predation is widespread - feeding on vertebrates: fish, amphibians, reptiles, birds and mammals. However, different representatives of birds, eating the same animals, obtain them in different ways, in different places and at different times of the day. Highly organized vertebrates - birds and mammals, as a rule, are accessible only to daytime predators and owls. Representing different orders, these birds have similar means of attacking prey. They are distinguished by strong, strongly curved claws, as well as a powerfully developed hook-shaped beak.

Among the predators there are highly specialized forms, such as the peregrine falcon (Falco peregrinus), widespread throughout the globe, but absent from much of South America and the tropical forests of Africa. The peregrine falcon feeds almost exclusively on birds, which it captures and kills in flight in the air. Stationary prey does not attract his attention. When going for prey in a dive, it moves at a speed of 75-100 m/sec. The peregrine falcon hunts medium-sized birds - pigeons, ducks, ravens, and less often - small ones. For hunting, it needs open spaces. The red-necked falcon or turumdi (Falco chiequera), which lives in India and tropical Africa, hunts in a similar way.

The goshawk and sparrowhawk, which also hunt mainly birds, act differently. They successfully pursue prey in wooded areas. The flight of hawks is very fast and agile. Short wings allow them to fly among trees and bushes, strong wing development (feathers attached to the wing finger) allows them to brake quickly, and a long tail allows them to quickly change the direction of flight. Despite the short length of the wings, the speed of flight is ensured by the strong development of the pectoral muscles, which drive the wing. Suddenly flying out from behind cover, the hawk attacks prey located not far from it. When chasing prey, they do not fly it high in the air, but strive to “press” it to the ground.

The majority of the reed harrier's prey (66-80%) also consists of birds, which it picks up from the ground with its paws. These are mainly brooding females, eggs and chicks of aquatic species, mainly ducks. When tracking prey, the reed harrier flies low over the surface of the earth or over water and reed thickets.

There are also ornithophages among eagles. For example, the hawk or long-tailed eagle (Hieraaetus fasciatus) and the dwarf eagle (Hieraaetus pennatus), found in the tropical and subtropical zones of the eastern hemisphere, feed mainly on birds, freely overtaking them in the forest with the help of fast and agile flight. They, like hawks, are distinguished by a long tail and relatively short wings.

The main food of many eagles are mammals of various sizes, most often rodents and less often young ungulates. Buzzards are typical myophages. Their main food is small rodents, which they look out for from a great height, flying in soaring flight over open spaces - forest clearings, meadows and fields, or waiting for prey on the ground, tree, telegraph pole, haystack, etc. One of the largest birds in Central and South America, the harpy (Harpyja) hunts during the day mainly on sloths and monkeys. It has rounded and relatively short wings, making it easy for the harpy to fly between trees, and an unusually strong beak and claws. The diet of the wide-mouthed kite (Machaerampus alcinus), which inhabits the tropical forests of Africa, is also unique. It feeds almost exclusively on bats, hunting only in the evening for half an hour. These birds often live in cities where there are many bats, which they chase over the platforms of railway stations.

Many owls also feed on small rodents. But these are nocturnal birds that do not compete for food with daytime birds. The talons and beak of owls have the same features as those of daytime predators, but they are distinguished by adaptations to a nocturnal lifestyle. Owls fly silently thanks to their loose and light plumage. This is facilitated by the strong elongation at the ends of the second-order barbs, which lie freely, as they are devoid of hooks. Huge eyes are directed forward, which increases the field of binocular vision. They look like cylinders narrowed at the front and widened at the back, in which the crystals are located. Owls' eyes are fast telephoto lenses. The huge pupil makes full use of the smallest amounts of light. Owls are far-sighted birds and are likely to have difficulty seeing in the immediate vicinity in front of them. They see well not only at night, but also during the day, as they have an amazing ability to reduce the size of the pupil. In their retina, it is not cones that predominate, but rods, thanks to which the degree of illumination is felt. The volume of the orbits is completely occupied by the eyeball, and the oculomotor muscles are reduced. Owls have almost lost the ability to move their eyes, so their gaze appears frozen. This immobility of the eyes is compensated by an extremely mobile neck. It rotates freely around the vertical axis by 270 0 C, and around the horizontal axis by 180 0 C.

The leading sense organ of owls is hearing. They are able to detect a mouse in the dark with an accuracy of 10. The ability of owls to detect sounds of low intensity and accurately determine the position of the prey is explained by the special design of the hearing aid. In many species of owls, the “ears,” formed by special folds of skin and feathers, reach extremely large sizes, almost closing at the top and bottom of the head. These folds, together with growing concentric rows of hard feathers around the beak, form the so-called facial disc. The disc feathers are movable and allow you to adjust the width of the ear slits. Particularly noteworthy for owls is the asymmetrical arrangement of the ear openings. Thanks to this, the pressure of the sound wave transmitted by the auditory ossicle to the relatively small area of ​​the oval window of the inner ear is increased by almost 40 times, and not 18, as in humans. The auditory ossicle does not rest on the center of the eardrum, but is located somewhat eccentrically, which also provides additional pressure. This type of hearing aid perceives high-frequency sounds most accurately. The hearing acuity of owls is not only determined by the specific structure of the ear, but is also largely associated with the complication of the structure of the auditory centers of the brain. The ability to accurately determine the place from which the sound made by the prey comes is associated with a special form of behavior of owls, the so-called clowning. Turning his gaze into the distance, the owl at times begins to systematically tilt his head first to one side, then to the other, or up and down. These movements are performed mainly by the neck with the body almost motionless. At the moment of active locating, owls change not only the position of the facial disc, but also its shape and even area. The latter becomes possible due to the mobility of the feathers and folds that form the facial disc. The facial disk, as an additional device that ensures the accuracy of prey location, is primarily necessary for those owls whose hunting is based on stalking. The transition to active search during flight has led in some species to the disappearance of the facial disc, which has lost its effectiveness and interferes with flight. At the same time, the plumage of these species becomes hard, since a silent sudden appearance for them loses its meaning, and the success of the hunt is determined only by the speed of flight.

Owls do not crush prey with their beaks, but swallow them whole. Too much fur, feathers and bones often end up in their stomachs. The undigested part of the food - compressed lumps - is regularly regurgitated by the owl in the form of pellets. For owls, pellets are more typical than for daytime predators, since the latter eat mainly muscles from their prey and digest bones better. Perhaps differentiated devouring of prey is difficult for owls, since they do not see well at close range.

For relatively few birds of prey, the main species of cabbage soup are snakes and lizards. This is how the widespread common snake eagle (Circaetus gallicus) feeds, tracking prey from the air and on foot. It is found throughout Africa, except the Sahara, in southern and central Europe and southwest Asia. Reptiles, especially snakes, serve as the main food for the peculiar secretary bird (Sagittarius serpentarius), living in the savannas of Africa. Although this bird can fly well, it usually stays on the ground and hunts on foot. Due to this, she has unusually long tarsus. With strong blows of strong claws, it kills relatively large prey. In the savannas of Africa, the buffoon eagle (Terathopius ecaudatus) lives, which feeds mainly on snakes, as well as lizards and turtles, but its diet is less specialized than that of other herpetophages. It also feeds on carrion and even attacks vultures, forcing them to regurgitate food. The buffoon eagle searches for prey in flight. In the air, it resembles a modern airplane: the wings are bent at an angle, the legs are thrown back. It flies at an altitude of about sixty meters at a speed of 70 to 85 km/h. He spends almost the entire day in the air, flying 300-500 kilometers during this time. The bird received the name buffoon eagle for the remarkable acrobatic exercises that it performs in the air during the breeding season.

The predatory type of feeding was replaced in some birds by feeding on carrion. For some, it exists along with eating fresh food. For example, an osprey that hunts live fish also eats dead ones. The fish eagle behaves the same way. Many species of eagles that feed primarily on live prey also feed on the carcasses of mammals. But among birds of prey there are also specialized forms that feed exclusively or almost exclusively on carrion. In the Old World, these are the common vulture (Neophoron perenopterus), griffon vulture (Gyps fulvus), Indian long-eared vulture (Saroogyps calvus), and bearded vulture (Gypaetus berdatus). In the New World, these are the condor (Vultur gryphus), the king vulture (Sarcoramphus papa) and the urubu vulture (Coragyps atratus). All of them have a large load-bearing surface, perfectly adapted to long flights in search of the corpses of large animals. Dull and weak claws make their paws unsuitable for killing live prey. First of all, scavengers eat the insides and then continue to peck out the carrion from the inside. In this regard, their neck is very long, in American vultures it is completely naked, and in representatives of the Old World it is covered with short, sparse down. Thanks to this, the plumage does not interfere with the penetration of carrion and the remains of decomposing food do not linger on it. The griffon vulture prefers decomposed corpses, while the bearded vulture prefers fresh meat. The griffon vulture, eating carrion from the inside, leaves the skin, tendons and skeleton intact. The bearded man feeds mainly on bones, which are easily digested in his stomach. It is known that bearded vultures also feed their chicks mainly with bones up to twenty centimeters long. Chicks almost never receive fresh meat.

Birds that feed on carrion often gather in flocks near their prey. Most of them search for prey by staying in the air using a soaring flight. Unlike others, the Urubu vulture often sits on the top of a tree and tries to catch the smell of carrion carried by air currents. He has a well-developed sense of smell and olfactory apparatus. Different species have different approaches to prey. Urubu, seeing prey, falls towards it from a height, opening its wings just above the ground. The bearded man first circles in the air for a long time, then descends lower and, finally, sitting on the ground at some distance, walks towards the prey.

Some of the birds that feed on carrion also attack living animals, for example, in the New World - condor, royal vulture, urubu vulture, etc., in the Old World - vulture. The peculiar behavior of a bearded man, who, under certain circumstances, seems to be trying to throw a ram, a mountain goat or a person into the abyss. That this is indeed the case is evidenced by the alarm among mammals and birds that constantly arises when a bearded vulture appears, while they do not pay any attention to the vulture. The stork, the African marabou (Leptoptilus crumeniferus), which is widespread in tropical Africa, also feeds on carrion. It has a large, featherless head. Often this bird can be seen soaring in the air, looking out for prey together with vultures.

The bulk of predators - fish eaters - are represented among birds associated with water bodies. The cosmopolitan osprey breeds in Europe, Asia, North America, Australia and North Africa. Fish are caught from flight by diving. Due to the method of hunting, the paws of the osprey are strong, with long, steeply curved claws and with an unfeathered shin and tarsus. The lower surface of the fingers is covered with pointed spines, which helps to hold slippery prey. The outer finger may be facing backwards. In Africa, the fish eagle (Haliaetus vocifer) lives near water bodies in tropical forests. He hunts by making short flights from his observation points located in the trees, often as if directly towards his prey. Apparently, he navigates by the light ripples that appear on the water when fish breathing atmospheric air float to the surface. Fish owls (Ketupa zeylonensis) are widespread in the tropical forests of Africa, as well as in South and East Asia. Their food consists of fish and crayfish. The owl catches them by entering the water and wading in the shallows, or by sitting near the water and lunging for prey. Hunts after dark. All representatives of the copepod order are piscivores. Some of them are gannets (Sulidae), living off the southwestern coast of Africa and western South America, as well as frigates (Fregatidae), and phaethons (Phaethontidae), inhabiting the tropical zone - oceanic forms. Phaetons move further away from the shores than others into the open sea. Pelicans (Palecanidae), living in large warm-water basins of the Old and New Worlds, and cosmopolitan cormorants (Phalacrocoracidae) obtain food in different ways. Gannets, frigates and phaetons snatch it out of the water as it falls rapidly from the air. Cormorants dive deep and pursue prey underwater. Pelicans are predominantly schooling birds that catch fish, noisily driving the whole group into shallow water and snatching them out of the water with their beak like a net.

Most herons also feed on fish to a greater or lesser extent. These birds, like other representatives of the wading order, are most numerous and diverse in the tropics. They are closely associated with fresh water bodies or at least with wet flooded spaces. Herons feed in shallow water, which is why they have long legs, a long neck, a long straight and sharp beak. Not only do they have a tarsus, but also a significant part of the lower leg is not feathered. Despite the considerable length of their legs, herons, like other ankle-dwelling animals, cannot run, walk slowly and fly away to escape danger. The hunting style of different herons is not the same. For example, living on the same shallows in the mangroves of the coast of southern Florida, different types of herons feed mainly on fish, but each species has its own fishing technique. The main method of fishing, best mastered by the night heron, is that the bird passively waits for fish, sitting on the protruding roots of mangrove trees. Other herons walk in the water, but each species stays at a different distance from the shore, in places that differ in depth. The Louisana heron, which stays closest to the shore, makes sudden movements, stirring up the water and scaring away hidden fish. A snowy egret entering deeper in search of prey slowly moves from place to place. The most sophisticated fishing method is used by the red heron, which hunts in even deeper places. She stirs up the water to scare the fish, then spreads her wings wide. The deceived fish take the shadow of the wings for a safe refuge and rush towards it, falling straight into the beak of the enemy. The size of the great blue heron allows it to hunt in places inaccessible to its smaller and shorter-legged relatives. Different types of herons hunt at different times of the day. Among them there are crepuscular, nocturnal and round-the-clock active forms.

Not all birds associated with water bodies feed on fish. The main food of small auks, which live in the Arctic Ocean and in the northern parts of the Atlantic and Pacific, are marine crustaceans and worms caught by diving.

Some waders that forage in water also feed on crustaceans, mollusks, worms, including microscopic planktonic forms. Thus, waders of the genus Haematopus are adapted to feed mainly on mollusks, the shells of which they very skillfully open. Their beak is simplified on the sides and pointed at the end and serves not only as a chisel, but also as a lever that unfolds the shell covers. Other waders collect food in damp places on land, not only from the surface of the soil, but penetrating deep into it. A characteristic feature of such forms is the probing of the soil using a highly sensitive beak, equipped with many tactile bodies. Their food consists mainly of insect larvae and worms. Often in such birds the beak is curved downwards, this helps to hold the captured prey. The beak of the snipe has the most interesting structure. It is capable of opening at the end underground without the beak widening at the base. With the help of a steeply curved beak, some waders extract food from crevices among stones near the river bank. The stone parka looks for food under pebbles on the sea coast, lifting and turning them over. Its beak is sharply upturned, simplified in the dorso-ventral direction and very strong. The New Zealand sandpiper (Anarhynchus frontalis) also turns over pebbles in search of food, but it does not lift them up, but to the side by moving its head to the left, and therefore its awl-shaped beak is curved to the right. The Spoon-billed Sandpiper's beak is strongly flattened from top to bottom and widened at the end into a small spoon, with which this bird grabs the smallest invertebrates in shallow bodies of water. Stilts and avocets, with beaks that have the character of tweezers, deftly drag the smallest food into shallow water. With their thin, tweezer-like beaks, phalaropes collect food in the upper layers of water, but not in shallow water, but in deep water. At the same time, they often rotate very quickly on the surface, forcing planktonic organisms to float closer to the surface. The foraging areas of yacans (Jocanidae) are peculiar; they have extremely long toes, and the weight of the body is distributed over such a large area that the birds can freely run far from the shore along the floating leaves of aquatic plants and peck food from their surface.

Incomparably larger than reptiles, birds feed on plant matter. First of all, a variety of fruits are used. Frugivorous forms are especially widespread in the tropics. These are banana eaters (Musophagidae) from the tropical forests of Africa, parrots (Psittaci) from the tropical zones of the Old and New Worlds, hornbills (Bucerotidae) common in the tropics of Africa and Southeast Asia, trogons and toucans (Ramphastidae) from the tropical forests of South America, Guajaro (Steatornithidae) from the montane tropical forests of South America. Some pigeons also eat fruits, but most of them eat the seeds of various plants.

Many temperate birds feed on seeds from trees, shrubs and grasses. For example, the taiga bird nutcracker or nutcracker feeds mainly on cedar seeds, deftly splitting the nut and removing the core from it. On the palate of the nutcracker there is a hard tubercle located above the pit in the tongue. The nut is placed in the hole and pressed with a tubercle, while it neatly splits into two identical halves. Crossbills peck seeds from the cones of spruce, pine, and larch trees with a specially adapted beak with an intersecting upper beak and lower beak. Grosbeaks eat grains of drupes and other fruit-bearing plants and seeds of a variety of tree species, including acorns, walnuts and pine nuts. Bullfinches consume seeds of various deciduous and coniferous trees, weed seeds and a wide variety of berries. Lentils feed on the seeds of various grasses and shrubs, as well as all kinds of berries. Goldfinches eat seeds of various herbs.

Tropical birds use not only fruits, but also flowers. Thus, hummingbirds (Trochilidae), living in North, Central and South America, flower beetles (Coerebidae), common in the tropics of Central and South America, and Hawaiian flower beetles (Drepanididae), inhabiting exclusively the Hawaiian islands, feed on nectar along with small insects, and flower beetles also pollen.

Significantly fewer birds eat green parts of plants. However, for the hoatzin (Opisthocomidae), which lives in the tropics of South America, the main food is aronica leaves. Geese feed exclusively on green vegetation, biting with their beaks the most tender parts of semi-aquatic or terrestrial plants. There are birds that use a wide variety of plant parts for food. Cranes living in steppes and swamps are almost exclusively herbivorous. These birds, which run well thanks to their long legs, feed on seedlings and grains of cereals, buds, stems, berries, tubers and roots of various plants. Various parts of plants, along with various invertebrates, are consumed by some representatives of the order Gallini and Anseriformes (ducks).

Polyphagia in the full sense of the word is rare in birds. An example of this could be the feeding of the crow, which is widespread on all continents of the northern hemisphere and prefers to settle near humans. The crow feeds on a wide variety of invertebrates, including mollusks, carrion, and exhibits a tendency towards predation, eating small rodents, eggs and chicks of various birds, including young poultry, lizards and fish. It also eats some parts of plants, grains of cultivated cereals, spruce seeds and various weeds. The black kite, which is distributed in Europe, Asia, Africa, with the exception of the Sahara and Northern Australia, also feeds heavily. It readily feeds on carrion and garbage, often found in Africa and South Asia in human settlements, as well as insects, fish, amphibians, reptiles, chicks and small mammals.

Unlike reptiles, whose activity in many areas is limited to only one season of the year, birds, which maintain it all year round, have a seasonal change of food. Thus, woodpeckers and tits feed on insects in the summer and switch to plant seeds in the winter. Woodpeckers feed in winter on spruce and pine seeds, and tits feed on seeds of deciduous trees. Starlings feed mainly on insects in summer, and in autumn they feed on fruits in gardens and vineyards. Black grouse, wood grouse and hazel grouse, which cannot forage for insects and plant seeds in winter, feed on needles, buds, shoots and catkins of deciduous trees. Birds also show an age-related change in food. Many granivorous birds feed their chicks with insects. Some tits feed younger chicks with soft food: spiders and small caterpillars, and older chicks with coarser food: large caterpillars, butterflies, beetles, etc. Pigeons feed their newly hatched chicks a white, mushy substance that is secreted by the walls of the crop. After a few days, the chicks begin to receive, along with this substance, grains softened in the crops of their parents. Feeding chicks with crop excretion products is also typical for some penguins. So, the geographical distribution of birds, distribution by habitat, morphological and behavioral characteristics - all this is determined by the nature of their diet.

A unique way to avoid food competition with other birds is unequal circadian rhythms and the division of birds into day and night birds. Despite the fact that circadian rhythms are based on biotic relationships that determine the ability to obtain food, abiotic factors, such as the degree of illumination, serve as signals for the onset of active time in birds. For a number of species, it has been established that birds begin to sing under certain lighting conditions. So, in the spring, the blackbird wakes up at illuminance of 0.1, the cuckoo - 1, the great tit - 1.8, the warbler - 4, the chaffinch - 12 and the house sparrow - 20 lux. The end of singing in the evening is also controlled by lighting conditions. In the tropics, as in temperate regions, birds sing and fall silent under strictly defined lighting conditions. Most believe that the beginning of singing marks the beginning of activity, and the field of its cessation immediately ends and all bird activity.

For nocturnal forms, the signal for the onset of activity is a decrease in illumination. So, owls fly out to hunt immediately after sunset. Around midnight there is a decline in hunting activity, or it even stops, but before dawn there is a new peak of activity. Consequently, the signal of activity for owls is the illumination characteristic of twilight. At night, gas exchange in owls increases, for example, in the long-eared owl, the respiratory coefficient is 0.76 during the day, and 0.83 at night. At night, the temperature of these birds also rises.

Birds spend the entire year in an active state. They do not hibernate, except that swallows and swifts in the summer, during prolonged bad weather, fall into torpor for a short period of time, unable to obtain food. The same is observed in hummingbirds and nightjars. In the temperate zone of the northern hemisphere, some birds adhere to nesting sites all year round, moving only slightly if at all. These are sedentary birds. A characteristic feature of nutrition is that, using different feeds in different seasons, they are constantly provided with food. These are hazel grouse, wood grouse, black grouse, sparrows, tits, jackdaws, nuthatches, wrens, woodpeckers, jays, magpies, etc.

Birds that cannot provide themselves with food in non-breeding areas throughout the year migrate to places where they can feed themselves. These are migratory and nomadic birds. Migratory birds travel tens of thousands of kilometers, and their wintering areas, as a rule, do not border their nesting sites. Nomads move shorter distances, and the territory of their winter stay is adjacent to the summer one. In the northern hemisphere, most birds are migratory. Examples of nomadic species include bullfinches, tap dancers, waxwings and crows. Crows in the middle zone migrate to the south, and their place is taken by crows nesting to the north. Some owls also wander, although many of them are sedentary.

The division into sedentary, nomadic and migratory birds is to some extent arbitrary. The same species in different parts of its range can be sedentary, nomadic, or migratory. For example, rooks living in the north of the species’ range are true migratory birds, but in the south, where they constantly find food, they are sedentary. True migratory birds in some years with a large food harvest can become sedentary and spend the winter at their nesting sites. For example, migratory birds - blackbirds - behave like sedentary birds during the years of high rowan harvest. Sedentary birds, when living conditions change, can turn into nomadic and even migratory birds. For example, buntings until recently were sedentary birds in the Moscow region and fed on oat grains, which were selected from horse manure. Due to the displacement of horses by cars, buntings began to migrate south for the winter. All this confirms that bird migrations have developed depending on the food supply of their habitats during all seasons of the year. Migratory birds in the northern hemisphere most often move south. For example, passerines that breed in Eurasia fly to wintering in South Asia, Africa and India, and from Canada and North America to Central and South America. Some birds spend two-thirds of the year on the breeding grounds, while others spend less, depending on how long the nesting sites are supplied with food. In some species, one of the two sexes migrates long before the end of reproduction. The males of some ducks nesting in the north leave the nesting area while the females are still sitting on their eggs. Female goldfinch sandpipers, on the other hand, leave Lapland in mid-June, shortly after laying eggs, while the males take care of the young. Thanks to this, the species, which has decreased in number at the nesting sites, is provided with food. This is probably also facilitated by cases when some individuals are migratory, while others of the same species are sedentary. Thus, in Western Europe, the overwhelming majority of females and young male chaffinches fly away from their nesting sites to the south, while older males remain to spend the winter.

As a rule, Palearctic migrants live in similar habitats in winter and summer. Almost all forest birds arriving in Africa spend the winter in forests with deciduous vegetation, either in thorny bushes or in savannas. No forest birds winter in lowland evergreen forests, and only three species are found in mountain evergreen forests. In genera in which some species breed in the Palearctic and some in Africa, the number of winter visitors from the Palearctic significantly exceeds the number of sedentary African birds. In Central America, resident birds do not begin nesting until migrants have flown to the breeding grounds, but some birds nest in the presence of migrants from the north. This is how local swallows behave in South Africa.

Flights (migration) of birds

As a rule, birds do not nest in wintering areas. But there are exceptions to this rule. The European white stork has been observed to nest repeatedly in South Africa, and the black stork nests here more often than in Europe. Thousands of European bee-eaters nest in these places, but it has not been established whether this bird nests in the summer in Europe or breeds chicks for the first time in a given year in South Africa.

Flights in the northern hemisphere are much stronger and more noticeable than in the southern hemisphere, but there are real migratory birds in the southern hemisphere. This applies to some penguins that leave their breeding grounds in Antarctica and swim to the shores of South America. Birds that nest in Patagonia spend the winter far to the north. From South Australia, birds can migrate as far as the Indo-Malayan Islands. There are about twenty known migratory birds in South Africa. Research into the migration of American tropical birds has only just begun, but it reveals that migration in these areas is associated with periodic changes in air humidity and precipitation levels, making it impossible for the birds to feed themselves without migrating. For example, a number of birds migrate at the beginning of the dry season from Madagascar to the African continent, until the onset of the rainy season forces them to return. The African nightjar (Semellophorus vexillaris) from Rhodesia and Angola migrates for the winter to Sudan, where at this time there are many flying termites - its main food.

As a rule, the same birds return to wintering grounds in the same places from year to year and follow the same migratory routes. If the latitudinal extent of the wintering area corresponds more or less to the extent of the nesting area, and the space lying between them does not present any special obstacles to the passage of birds, then they fly in a wide front. With a relatively more limited extent of the winter range compared to the nesting range, flying birds, when approaching wintering, are concentrated in a narrower area.

Flyways follow the course of a particular landscape. Thus, coastal coastal birds usually stick to the coastline of the seas, river birds - rivers, mountain birds - mountains, and forest birds accumulate mainly in forest areas. Spring and autumn bird migration routes do not always coincide. The flyways probably follow the routes of dispersal of the species both to nesting and wintering grounds. Thus, on the territory of the CIS, the Dubrovnik, which settled relatively recently from east to west, first flies east in the fall, and then only south, to India, despite the fact that its new breeding areas lie at the same longitude as India, and he could reach wintering grounds the shortest distance in a straight line.

Birds fly to their homeland at a time when the conditions necessary for their life have already developed in nature: familiar food and shelter. For example, warblers appear when young reeds grow up, and swallows appear when insects appear in the air. Thanks to this, a constant range of arrivals is observed everywhere, stretching for one and a half to two months. In the temperate zone of the northern hemisphere, rooks are the first to appear in mid-March, and swifts are the last to appear at the end of May. Birds that arrive late usually fly away early. At the beginning, local individuals of this species appear and only later nesting far away in the north.

The most common phenomenon is the early arrival of males compared to females. The significance of this fact is seen in the male securing the nesting territory immediately upon arrival, which provides future offspring with a sufficient amount of food. Young birds are the last to fly to their homeland, and some do not reach it in the first year of life or remain in wintering areas. In autumn the opposite picture is observed.

Normally, large birds do not rise above 1500 m during migration, preferring to generally stay below 1000 m above the ground. Small birds fly normally below 300 m. Different species adhere to different heights. In addition to the nocturnal birds themselves, most of the birds that fly at night are small passerine birds, waders, ducks and many others. Only in the daytime are predator flights observed. Small birds with a very high metabolic rate cannot starve even for one day. As a result, they do not feed during the day, sleep for a very short time, and continue to fly for a significant part of the night and twilight. Large daytime predators either feed along the way or are able to go without food for some time, continuing their flight and resting in their sleep at night.

The average migration speed is about 200 km/day; for migrants within the continent it is 50–100 km/day. Long-distance migrants, crossing barriers, are able to fly 2000-3000 km in a continuous flight. Several studies have shown that the migration speed of females is significantly higher than that of males.

In most species of the temperate zone, especially long-distance migrants, autumn migration occurs before the onset of unfavorable conditions with an abundance of food. Bird migrations are carried out due to the development of a special seasonal state - migratory. The migration situation consists of many elements. This is an increased consumption of food, and in some birds a change in the composition of food - a transition to feeding on more high-calorie plant foods, fat deposition, migratory flight, orientation of movement in the direction of migration, the formation of special daily rhythms of feeding and migratory behavior, a clear dependence of this behavior on the level of energy reserves, loss of territoriality and increased gregariousness. The loss of one of these elements is enough to stop migration. The migratory state is determined by a complex of physiological changes.

Sedentary birds of temperate and high latitudes expend no less energy per year than migratory birds of the same size. In migratory birds, the additional energy consumption for migration is compensated by its more economical expenditure in winter compared to sedentary birds in extratropical regions.

In some cases, a guiding landscape line, vector, and other similar factors may be used by the bird to maintain its chosen direction. However, there is no doubt that they mainly use some kind of global guidelines for orientation. This is orientation to the sun and stars. In solar orientation, the choice of direction is based on maintaining a certain angle of motion relative to the sun. The position of the sun relative to the pole changes during the day, and to maintain a constant direction it is necessary to correct for the apparent movement of the sun by an average of 15 0 per hour. This requires the use of an endogenous time sensor - the biological clock.

Birds caring for their offspring

Birds are distinguished by highly developed care for their offspring. They tend to incubate the eggs. The rudiments of such behavior are also known in reptiles, for example, in pythons. But this could not become widespread among cold-blooded reptiles. The incubating bird also protects the clutch either by actively attacking the enemy, or by moving it away, pretending to be wounded, or simply camouflaging it thanks to the protective coloring of its plumage. Along with this, developing chicks find themselves in an optimal temperature regime for them, which, as a rule, exceeds the ambient temperature and is close to the body temperature of adult birds. In some cases, for example in deserts, the brooding bird, by shading the eggs, saves them from overheating. Thanks to heating, the period of development of eggs in birds is significantly reduced. Thus, in temperate latitudes, small passerines incubate for an average of 15 days, and large predators for about one and a half months, while in the same conditions reptile eggs develop for 2-3 months.

The coot takes care of the offspring and feeds the chicks. Photo: Tony Hisgett

Reducing the period of development of eggs is an important adaptation, since the period of individual development, during which animals are most vulnerable and most easily die, is shortened. The reduction in the development period of chicks occurs not only due to an increase in incubation temperature, but also due to hatching before completion of development. This is only possible due to the fact that there is a strong and lasting connection between parents and offspring. Chicks, having hatched and not completed development, cannot live independently and need the care of their parents. Depending on the stage at which the chicks hatch and what form of care the parents show them, the chicks are in brood, half-brood and fledgling stages. Brood birds include ostriches, geese, chickens, waders, rails, sandgrouses, grebes, loons, cranes, etc. Their chicks are born sighted with open auditory canals, with a constant body temperature, very soon they can acquire the ability to move independently, and then and look for food. But their body is covered not with the plumage characteristic of adults, but with thick chick down. The female, and less often the male, stays with the brood for a long time. By giving a danger signal, the parents force the chicks to scatter and hide, becoming invisible. They warm them, protecting them from rain and cold, lead them in search of food, and show it to them.

The nestlings include phylogenetically younger birds: passerines, woodpeckers, coraciiformes, swiftlets, pigeons, cuckoos and tubenoses. Their chicks hatch less formed than those of brood birds, blind, with closed auditory canals, often completely naked or covered with sparse chick down, located only on the pterilium and not covering the entire body. Their temperature, like reptiles, is not constant. Their motor capabilities are limited to raising their heads and opening their mouths when their parents approach. Such chicks remain in the nest for a long time (from 8 to 22 days in different species). Parents either actively defend the nest from enemies, or lead them away from it, pretending to be wounded. They intensively feed the chicks, as a rule, remove the litter from the nest and warm the brood during the first half of its nesting life. Half-brood chicks at birth are only slightly inferior in development to brood chicks, but remain in the nest for a long time and are fed by their parents. Semi-broodbirds include diurnal raptors, owls, gulls, tubenoses, most auks, wading birds, and nightjars. Half-broods occupy a sort of intermediate position between brood and nestlings. Obtaining food from them requires specialization and, therefore, is not accessible to the chicks. In this case, feeding becomes inevitable. With the development of the instinct to feed chicks, it became possible to peck them out of the egg even earlier, which is what happens in chicks. This turned out to be useful, since the transition to active feeding is accompanied by the development of chicks with amazing speed, as a result of which their infant mortality decreases. Broodbirds lay a larger number of eggs than birds feeding their chicks. Their clutch can contain a maximum of 22 eggs. In nestlings and half-broods, the number of eggs varies from one to six, and only as an exception, in some species there are more. The brood egg is relatively larger, as it contains a large supply of nutrients, ensuring longer development in the egg.

In brood nests, with rare exceptions, nests are located on the ground and have a very simple design. Sometimes they may not exist at all. The nest can simply be a depression in the soil without lining or with a lining of dry herbaceous plants. In the best case, this nest is marked by a loose wall of plant material. Of the brood ducks, only some ducks make nests in hollows (mergansers, goldeneyes, goldeneyes), which provide them with reliable shelters, but complicate the descent of the chicks to the ground. The black sandpiper nests in the nests of other birds in trees. In half-broods and chicks, whose chicks do not search for food on their own and may not leave the nest for a long time, the nest does not have to be on the ground, and for the majority it moves to the upper tier: to bushes, trees, rocks, hills and human structures. In the simplest case, the nest has the shape of a platform or bowl. Some build closed nests with a roof and a side entrance. Nests may be placed near trunks or on branches, or suspended in the air on the terminal branches of trees or between the stems of herbaceous vegetation. Hanging nests are especially widespread in the tropics. This protects them from predators and tree snakes.

Dressmaker's warblers (Cisticola) make nests between durable leaves sewn together with palm fibers, threads of plant fluff or cobwebs. The palm swift (Cypsiurus parvus), common in Africa, nests on the undersides of coconut palm leaves. In strong winds, the underside of a palm leaf is not a very stable place for a nest, but the palm swift protects itself by gluing the eggs to the nest with saliva. Saliva takes a large part in nest building in swifts and swallows. It is secreted in large quantities by greatly enlarged glands. In swiftlets (Caalocalia), saliva becomes almost the only material for nest building. In swallows, more or less closed nests are built from lumps of dirt and blades of grass, which are firmly held together with saliva.

One of the most common and well-known birds in Argentina, the red ovenbird (Furnarius rufus) builds a nest from drying mud on a tree branch, the eaves of a house, a rock or a fence post. Because birds mix mud with straw and plant fibers, this building material, as strong as reinforced concrete, provides shelter from any weather. An oval or spherical nest has one side hole. A partition behind the entrance hole creates a sort of hallway that leads into the nesting chamber.

Birds of semi-desert and desert regions often nest in burrows. Wheatears that live in Eurasia occupy rodent burrows, while others dig themselves. Thus, in the Peruvian highlands, birds from the stove family nest in burrows dug in loose soil. The ground nuthatches (Geositta) and rock nuthatches (Upucerthia), and ground tyrants, such as the rock flycatcher (Muscisaxicola) and ground woodpeckers (Colaptes rupicola), also dig burrows in these places. Rabbit owls (Speotyto cunicularia) inhabiting the Peruvian deserts also dig holes for nesting. African desert and savannah birds also nest in burrows, such as the red-necked bee-eater (Merops nubicus) and the red-necked bee-eater (Melittophagus bullocki). Kingfishers (Alcedinidae), which are especially numerous in Southeast Asia, also nest in burrows. Many tropical forest birds nest in hollows. Woodpeckers, trogons, bearded frogs, dart frogs and sloths hollow them out themselves, while others use ready-made ones.

Some birds nest colonially. This is especially true for tropical birds. The grub-eater (Crotophaga ani) and great ani (Crotophaga major), abundant in much of South America, nest most often in “communal apartments”. Up to 25 thousand birds from one flock can unite to build a common nest in which females lay their eggs. All birds take part in hatching and caring for the chicks. Nests of wedge-tailed parrots (Myiopsitta monachus), adjacent to one another, are suspended at the ends of branches and form a dense plexus. Such a collective nest reaches one meter in diameter and weighs 225 kg, but each pair has its own separate room. The peculiar nests of the social weaver (Phlaeterus socius), which inhabits Africa, are piles of dry grass and twigs. They are up to 3.5 m in diameter, their height reaches up to 1.5 m. Holes are made in this pile - separate entrances to individual nests, lined inside with feathers. At first, 2-3 pairs settle in the nests, then from 50 to 70, and sometimes up to 100 birds. Other weavers hang one or more nearby trees with a mass of independent nests. Some burrowers nest colonially, such as bee-eaters and sand martins, as well as sea-coast birds - tubenoses and copepods native to South-West Africa, guillemots of the northern seas and gulls.

All birds that feed their chicks, with rare exceptions, are monogamous, i.e. the male mates with one female and stays near her, sharing concerns about the brood until the end of the chicks' development. Some birds mate for life. These are, for example, pigeons. For others, caring for chicks takes on a unique character. Thus, during the incubation period, the female hornbill (Tckus deckeni) immurs itself in a hollow, cementing the wall with a mixture of saliva and soil, which the male brings to her in pellets. For communication with the outside world, she leaves only a narrow gap through which the male feeds her. With the appearance of the chicks, the female flies out of the hollow and, together with the male, feeds the offspring.

Among the brood species there are both monogamous and polygamous. In polygamy, one male mates with several females and does not care about the offspring. Only in rare cases do males sit down to incubate the clutch and raise a brood, and the female’s activity ends with the laying of eggs. This is how, for example, the phalarope, which lives in the tundra, behaves when it mates with several females, who lay their eggs in one nest and leave them in the care of the male.

Much less common in the bird world is polyandry, when one female mates with several males. This is how three-fingers (Turniceps) behave - steppe and meadow birds of tropical and subtropical countries of the Old World. A clutch of two to four eggs is laid by the female several times (up to 33) and distributed among the males, who perform all the duties of incubating and raising the chicks. Polyandry is observed in the tundra inhabitant of the flat-nosed phalarope, in the colored snipe (Postratulidae), common in Africa, South Asia and Australia, in the tinamous (Tinamidae), living in Central and South America, as well as in the cuckoo, which lays one egg in its nest for a long time various birds.

Birds are characterized by sexual dimorphism. Individuals of different sexes may differ in size. Males are often large and brightly colored, while females have a protective coloration that makes them invisible when incubating. In cases where only males take part in raising the offspring, on the contrary, females are brighter in color. The bright and species-specific coloring allows the female to recognize the male of her species and stimulates her to mate. The same role is played by the singing of the male and mating games - current in birds.

The song of birds is strictly specific for each species and, as a rule, the more sharply different, the smaller the differences in the color of related species living nearby. It is believed that singing not only attracts the female and stimulates her to reproduce, but also serves as a means of protecting the nesting territory. The song serves as a signal that the territory is occupied by other males.

Showing, during which males, having gathered in a certain place, perform ritual movements, and females watch them, represents a highly specialized form of mating behavior. Showing, characteristic of polygamous birds, is observed in grouse and other gallinaceae. Many tropical birds also perform the same mating displays - the peacock-like Asian argus (Argusianus), the birds of paradise (Paradiseidae) of New Guinea, the orange cock of the rock (Rupicola rupicola) of the South American mountains, the tiny manakins of tropical America and some hummingbirds. The leks of dancing widow weavers, inhabitants of East African savannas, sometimes consist of 100 or more individual lek areas, each of which is a trampled circle with a tuft of grass in the center. Near this bunch, perhaps symbolizing a nest, the male dances.

Pair formation among Arctic terns is preceded by a certain ritual. The male brings a small fish to his chosen girlfriend. Then both birds fly over the colony, passing this symbolic gift to each other several times. The male, having descended to his site, once again brings the fish. If he is accepted and the bird that accepted it obediently allows him to peck itself, then the agreement has taken place.

Activity associated with reproduction, as well as feeding, has a daily rhythm in birds. In many cases, both of these forms of activity diverge in time and most of the day is spent collecting food, and the morning and evening dawns are devoted to processes associated with reproduction. For example, it is at this time that starlings are especially energetically busy building a nest. This is also the time when most birds lay their eggs. The combination of singing and feeding rhythms is more complex and varies from bird to bird. There are several types of daily rhythm of birdsong: crepuscular, when two peaks that stand out sharply above the general level of activity occur in the morning and evening twilight; nocturnal, when both of these peaks come closer to each other at night; morning, when activity reaches its maximum in the morning hours, then decreases until the evening, and, finally, daytime, when the only maximum occurs approximately in the middle of the day. In the first two cases, singing and feeding are separated in time, in the remaining cases they are combined to a greater or lesser extent.

The beginning and end of singing are stimulated by illumination. As a result, in spring birds begin to sing later and end earlier than in summer, when the length of the day increases. For the same reasons, the duration of activity of birds living in the north is longer than that of southerners, even those belonging to the same species. However, the specifics of the daily rhythm of singing of each species also depends on biotic factors - relationships with species living nearby. The meaning of this relationship is that birds “divide” the hours of greatest activity among themselves and thereby ensure better audibility of the signals they send to representatives of their species. Thus, in the temperate zone of Eurasia, thrushes are most active between 3 and 4 o'clock, warblers - 5 and 6, wagtails - 6 and 7, finches - 9 and 10 o'clock.

But the distribution of time between closely related species is even more fragmented, and if you observe birds every five minutes, it will turn out that during this time only one species from a particular family sings energetically, while others are in decline at this time. The degree of singing activity depends on the number of singing species in a particular territory. In those territories where it is greatest, singing activity is the least. Typically, such ratios are typical for the central parts of the range. As you move away from it to the boundaries of distribution, the number decreases, and the singing activity increases. This is probably due to the fact that sex ratios change, the possibility of pairing decreases, and single males sing energetically.

Bird song activity varies throughout the season. It is greatest before the formation of pairs, least during feeding of the chicks. If a bird nests several times a year, the singing cycle repeats again.



The dispersal of seeds and fruits by animals is called zoochory (from Greek zoon– animal, choreo- I’m moving away, moving forward).

Many juicy fruits are readily eaten by birds. When searching for food, birds usually rely on the appearance and taste of the fruits and seeds they eat, so the fruits they distribute must be brightly colored and tasty (from the birds' point of view, of course). And here’s what’s interesting: before they ripen, the fruits and seeds are green in color and contain a lot of acids and bitterness, which scares away birds. But smell has no meaning for birds - their sense of smell plays a lesser role in searching for food than vision. It remains to add that the transfer of seeds and fruits by birds is called ornitochory (from Greek ornis- bird).

When passing through the digestive tract of birds, the seeds are not digested and remain viable. Therefore, when they come out with droppings, they not only find themselves at a considerable distance from the parent plant, but are also surrounded by nutritious organic matter (the droppings themselves), which enrich the soil around the seed and promote its germination and further development. In the droppings of crows and jackdaws, for example, completely intact drupe bones are found.

In certain plants, seeds cannot germinate at all without first passing through the digestive tract of birds, where they are exposed to digestive enzymes that soften the seed coats. Thus, the seeds of some plants, after the extermination of the flightless dodo bird by man, did not produce seedlings for several centuries. However, when these seeds were fed to the geese and then planted in the soil, they sprouted! Another example is the Galapagos tortoise and wild tomato seeds.

Seeds can be spread by mammals. Most often these are various monkeys, rodents and bats. The seeds of many cereals pass through the digestive system of ungulates without damage, and their germination rate even increases. Predators can also take part in endozoochory: for example, ripe watermelons, if possible, include foxes and jackals in their diet, bears willingly feed on berry fields, etc.

Conclusion: Endozoochorous plants have succulent fruits or inflorescences with bright colors to be easily visible, or with a strong aroma to attract animals from a long distance, especially at night. The seeds also have a durable shell that protects them from digestion. Thanks to the shell, the seeds pass through the digestive system unharmed.

Very often, animals do not immediately eat seeds or fruits, but carry them away and store them in reserve, especially during periods of abundance of food. When squirrels eat seeds, for example, they never eat them all. Lost seeds are enough for plants to disperse. Animals often carry the cones far from the place where they are collected. They completely forget about some of their storerooms; in addition, the owner may simply die before he has time to use them. In such cases, the seeds will germinate after some time, often at a considerable distance from the parent plants. This method of seed dispersal is called synzoochory (from Greek. syn- together).

Supplies are made by many birds (for example, jays, moths, etc.) and rodents (mice, squirrels, chipmunks, hamsters, etc.). Moreover, the amount of stored food can be quite significant.

Ants play an important role in the distribution of seeds and fruits. This phenomenon is called myrmecochory (from Greek myrmex- ant). Many ants bring seeds and fruits of various plants into their home. Such seeds have special growths with nutritious and tasty oil. Such seeds include primrose, snowdrop, violet, spurge, corydalis, hoofed grass, celandine, fireweed, goose onion, coppice, chickweed, woodruff, etc.

Nature is very persistent in helping plants spread their seeds. She invented and implemented a huge number of devices that allow new shoots to appear at great distances from the mother plant. For example, light dandelion seeds are equipped with parachutes, allowing them to fly with the wind, and thistle seeds firmly cling to human clothing and animal fur with small thorny hooks. And who can help the oak tree?

What does an acorn look like?

Oak is a powerful and strong tree. It has a massive trunk and a powerful crown. It is no wonder that its seeds are not particularly light. The oak sower must have enough strength to lift and carry the heavy and smooth fruit.

The acorn has a leathery pericarp and a hard cap. This is a single-seeded fruit formed from fused simplified oak inflorescences. The fruits of chestnut and beech are also acorns, but the cap of an oak acorn always contains only one fruit, while the cap of a beech and chestnut may contain several fruits.

Bird eating acorns

A small bird with bright plumage lives in the forest. It's called a jay. This bird is an oak sower. The bird is no larger than a pigeon. She has short wings and a strong beak. It is difficult for the bird to cover long distances, but in the treetops it feels quite confident and is able to move along the branches quite quickly.

Most often, jays settle in deciduous forests, where many oak trees grow. The basis of the birds' diet is plant food, but they feed the chicks with insects, and adult jays do not completely give up animal food. But the favorite delicacy of feathered fidgets is acorns. Birds split the dense shell with their beaks, and when they are full, they begin to take them to secluded places. In preparation for winter, a jay can store up to four kilograms of reserves in various hiding places. Many hiding places are forgotten, and acorns hidden in the pine litter sprout. This is why people believe that the jay is an oak sower. Thanks to the thrifty little bird, young oak shoots appear in different places. This helps preserve the majestic trees.

Birds are the youngest in evolutionary terms, highly developed animals, which are characterized by walking on two legs, feather cover, wings and beak, warm-bloodedness with an intense metabolism, a well-developed brain and complex behavior. All these features of birds allowed them to spread widely across the globe and occupy all habitats - land, water, air; they inhabit any territory from high polar latitudes to the smallest oceanic islands.

The habitat was a selection factor in the evolution of birds (body structure, wings, limbs, methods of movement, food production, features of breeding).

Birds are characterized by seasonal cycles, which are most noticeable in migratory birds and less pronounced in migratory or sedentary birds. The greatest species diversity of birds is concentrated in the tropical zone. Almost every bird species can live in several different biogeocenoses.

The most numerous group of forest birds includes carnivores, herbivores and omnivores. They nest in hollows, on branches, on the ground. Birds of open places - meadows, steppes, deserts - build nests on the ground; Coastal birds nest on rocks, forming bird colonies, where several species of birds not only live together, but also protect themselves from enemies.

Birds are characterized by clearly defined dynamics of population changes. Thus, the maximum of birds on Earth (up to 100 billion individuals) is observed after the emergence of the young, the minimum - by the beginning of next summer (decrease in number up to 10 times). Human economic activity plays a major role in changing the number of birds. The areas of forests, swamps, meadows, and natural reservoirs are being reduced, and some birds are simply exterminated.

The role of birds in food chains is great, since they represent the final links of many food chains.

Birds are of great importance in the distribution of fruits and seeds. In human economic activity, the importance of birds is mainly positive: they exterminate rodents, insect pests, and weed seeds, which can be considered as biological protection of fields and gardens. Birds must be protected and protected, fed, especially in winter, and their nests must not be destroyed. Without birds - so bright, mobile, loud-voiced - our forests, parks, meadows, and reservoirs become joyless and dead.

The damage caused by birds is incomparably lower than their benefit. They devastate orchards and vineyards, peck out sown seeds, pull out seedlings, so they have to be scared away. Cases of bird collisions with airplanes have become more frequent. Birds carry infectious diseases - influenza, encephalitis, salmonellosis, and spread ticks and fleas.

A person is engaged in poultry farming, raising poultry, as well as ornamental and songbirds.

80 species of birds are listed in the Red Book of the USSR.

There are about 8,600 species of birds in the world fauna, of which approximately 750 species are found within the territory of our country. Birds are common on all continents of the globe with the exception of the interior regions of Antarctica; some of them spend most of their lives on the open sea. On land, different species of birds are found everywhere where there is plant or animal food for them - in forests, bushes, parks, shelterbelts, meadows, swamps, deserts, mountains and tundra.

Class characteristics

Birds are very similar in structure to reptiles and represent their progressive branch, the evolution of which followed the path of adaptation to flight. Birds are often combined with reptiles into the group of lizards (Sauropsida). Birds are bipedal amniotes whose forelimbs have developed into wings; the body is covered with feathers, the body temperature is constant and high.

The organization of birds is adapted to flight conditions. The body is compact, the skeleton is extremely lightweight. The spread wings and tail form an area much larger compared to the area of ​​the body. In the body structure of birds, one can note not only features characteristic of birds, but also features common to reptiles. Thus, there are no glands in the skin of birds, with the exception of the coccygeal gland above the root of the tail. Some birds also lack this gland.

Coverings of the body. The skin is very thin. There are horny sheaths on the beak, horny scales on the limbs, and claws on the fingers. Derivatives of the skin are feathers, phylogenetically related to scaly formations (this is indicated by the similarity in the development of feathers and scales in the early stages). Feathers cover the outside of a bird's body, help retain heat (thermal insulation function), provide streamlining of the body, protect it from damage, and form load-bearing planes in flight (wings, tail).

There are contour and down feathers.

Outline feathers consist of a strong and elastic hollow horny trunk (rod) and a soft fan. The fan is formed by a dense network of thin horny plates - barbs. The first-order barbules extend parallel to one another from the rod, on both sides of which numerous thinner second-order barbs extend, the latter interlocking with small hooks. There are long and especially strong feathers - flight feathers - they form the plane of the wing; long and strong tail feathers form the plane of the tail, the remaining integumentary contour feathers provide a streamlined body shape. 9-10 primary flight feathers are attached to the rear edge of the skeleton of the hand; during flight they form a thrust that carries the bird forward, and to a lesser extent - a lifting force. The secondary flight feathers are attached to the forearm and form the main load-bearing surface of the wing. On the leading edge of the latter there is a small wing with several short feathers that make it easier for the bird to land. Tail feathers take part in flight control and braking.

Down feathers have a thin short shaft and a soft fan with thinner and fluffy beards, without hooks (i.e. not connected to each other). Down feathers increase thermal insulation and help reduce heat transfer.

Birds molt periodically (once or twice a year), and new feathers grow in place of old feathers.

Skeleton. The bones of the skeleton are filled with air (pneumatic) and are lightweight. The thickness of the bones is small, the tubular bones are hollow inside, except for air, they are partially filled with bone marrow. Many bones fuse together. Thanks to these features, the bird's skeleton is light and strong. The spine is divided into five sections: cervical, thoracic, lumbar, sacral and caudal. The cervical vertebrae (there are from 11 to 25) are movably connected to each other. The vertebrae of other sections are fused to each other and are motionless, which is necessary during flight. The thoracic vertebrae are almost motionless; the ribs are attached to them. The ribs have hook-shaped processes that overlap the adjacent posterior ribs. The thoracic vertebrae, ribs, and broad breastbone, or sternum, form the rib cage. The sternum has a high ridge at the bottom - the keel. Powerful muscles that move the wing are attached to it and the sternum.

All lumbar and sacral (there are two) vertebrae are fused with each other and with the iliac bones; several caudal vertebrae join them, forming the complex sacrum characteristic of birds. It serves as a support for a pair of hind limbs, which bear the entire weight of the body. There are 5-9 free caudal vertebrae, the terminal caudal vertebrae are fused into the coccygeal bone, to which the tail feathers are attached.

The forelimb girdle consists of three paired bones: coracoids, scapulae and clavicles. The skeleton of the forelimb, which turned into a wing, is significantly modified. The wing skeleton consists of one humerus, two forearm bones (ulna and radius), several hand bones (most of them fused to form one bone) and three fingers. The skeleton of the fingers is sharply reduced.

When moving on land, the entire weight of the body is transferred to the pelvic girdle and hind limbs, and therefore they are also transformed. The hind limb girdle consists of three pairs of bones that fuse to form the pelvis. Along the midline of the body, the pelvic bones do not fuse together; this is the so-called open pelvis, which allows birds to lay large eggs. The skeleton of the hind limb is formed by long and strong tubular bones. The total length of the leg exceeds the length of the body. The skeleton of the hind limb consists of one femur, fused bones of the lower leg and foot bones that form the tarsus, and four toes.

The skull is characterized by complete fusion of all bones until the sutures disappear, extreme lightness and large eye sockets close to each other. The jaws of birds are represented by a light beak, devoid of teeth.

Musculature well developed, its relative mass is greater than that of reptiles. At the same time, the abdominal muscles are weaker than the pectoral muscles, which make up 10-25% of the total mass of the bird, i.e. approximately the same as all other muscles combined. This is due to the fact that the paired pectoralis major and minor muscles, starting on the sternum and its keel, lower and raise the wings during flight. In addition to the pectoral muscles, the complex work of the wing in flight is controlled by several dozen small muscles attached to the body and forelimbs. The muscles of the neck and legs are very complex. Many birds have a special device on the tendon of the deep toe flexor muscle that automatically secures the toes in a compressed state when the bird wraps them around a branch. Therefore, birds can sleep sitting on branches.

Digestive system. The digestive organs are characterized by the complete absence of teeth in modern birds, which greatly facilitates the body for flight. In granivorous birds they are replaced by a muscular stomach, which serves for mechanical grinding of food, while the glandular stomach serves for enzymatic action.

The digestive organs begin with the beak - this is the main organ for capturing food. The beak consists of an upper part (the mandible) and a lower part (the mandible). The shape and structural features of the beak are different in different birds and depend on the method of feeding. The tongue is attached to the bottom of the oral cavity; its shape and structural features depend on the nature of the food. The ducts of the salivary glands open into the oral cavity. Some birds have the enzyme amylase in their saliva and digestion of food begins in the oral cavity. Swallows and some swifts use sticky saliva when building nests; woodpeckers have insects stuck to their long tongue moistened with sticky saliva. Food moistened with saliva is easily swallowed and enters the esophagus, the lower part of which in many birds forms an extension - a crop (in which the food is soaked and partially digested). Further along the esophagus, food enters the thin-walled glandular stomach, in which numerous glands secrete digestive enzymes. Enzymatically processed food passes into the gizzard. The walls of the latter have well-developed strong muscles, thanks to the contraction of which food is ground. The ground food enters the duodenum, into which the ducts of the pancreas and gall bladder flow (birds have a two-lobed liver). The food then passes into the small intestine and then into the hind intestine, which is not differentiated into the colon and rectum and is significantly shortened. Through the hind intestine, undigested food remains are excreted into the cloaca.

Birds are characterized by high digestion intensity. For example, sparrows digest caterpillars in 15-20 minutes, beetles in about 1 hour, and grain in 3-4 hours.

Respiratory system. The respiratory organs begin with the nostrils, located at the base of the beak. From the mouth, the laryngeal fissure leads into the larynx, and from it into the trachea. In the lower part of the trachea and the initial sections of the bronchi there is the vocal apparatus of birds - the lower larynx. The source of sounds is the membranes that vibrate as air passes between the last cartilaginous rings of the trachea and the semi-rings of the bronchi. The bronchi penetrate into the lungs, branching into small tubes - bronchioles - and very thin air capillaries, which form an air-carrying network in the lungs. Blood capillaries are closely intertwined with it, gas exchange occurs through the walls of the latter. Some of the bronchial branches are not divided into bronchioles and extend beyond the lungs, forming thin-walled air sacs located between internal organs, muscles, under the skin and even inside hollow bones. The volume of the air sacs is almost 10 times the volume of the lungs. The paired lungs are small, are densely spongy bodies, and not bags, like in reptiles, and have little extensibility; they grow into the ribs on the sides of the spine.

In a calm state and while moving on the ground, the act of breathing is carried out due to the movement of the chest. When inhaling, the chest bone lowers, moving away from the spine, and when exhaling, it rises, approaching it. During flight, the sternum is motionless. When the wings are raised, inhalation occurs due to the fact that the air sacs stretch and air is sucked into the lungs and sacs. When the wings lower, exhalation occurs, oxygen-rich air moves from the air sacs into the lungs, where gas exchange takes place. Thus, oxygenated air passes through the lungs both during inhalation and exhalation (so-called double breathing). Air sacs prevent the body from overheating, as excess heat is removed with the air.

Excretory system. The excretory organs are represented by two large kidneys, constituting 1-2% of body weight; they lie deep in the pelvis on both sides of the spine. There is no bladder. Through two ureters, uric acid in the form of a white mushy mass flows into the cloaca and is excreted out along with excrement without remaining in the body. This reduces the bird’s body weight and is important during flight.

Circulatory system. The heart of birds is relatively large, its mass making up 1-2% of body weight. The intensity of the heart is also high: the pulse at rest is 200-300 beats per minute, and in flight - up to 400-500 (in medium-sized birds). The large volume of the heart and rapid pulse ensure rapid blood circulation in the body, intensive oxygen supply to tissues and organs and removal of metabolic products.

In the structure of the heart, noteworthy is the complete division of the heart by a longitudinal continuous septum into the right venous and left arterial halves. Of the two aortic arches, only the right one, originating from the left ventricle, is preserved. The large and small circles of blood circulation are completely separated. The systemic circulation begins from the left ventricle and ends in the right atrium; arterial blood is carried through the arteries throughout the body (all organs are supplied only with arterial blood), venous blood through the veins enters the right atrium, and from it into the right ventricle. The pulmonary circulation begins from the right ventricle and ends in the left atrium. Venous blood through the pulmonary arteries enters the lungs, is oxidized there, and arterial blood through the pulmonary veins enters the left atrium, and from it into the left ventricle and into the systemic circulation. As a result of the fact that arterial and venous blood do not mix, the organs receive arterial blood. This enhances metabolism, increases the vital activity of the body, and causes a very high and constant body temperature of birds (42-45 ° C). The constancy of body temperature and its independence from environmental temperature is an important progressive feature of birds and mammals compared to previous classes of animals.

Nervous system. The brain has relatively large hemispheres and optic lobes, a well-developed cerebellum, and very small olfactory lobes. This is associated with more complex and varied behavior and flight ability. All 12 pairs of cranial nerves arise from the brain.

Of the sense organs, vision is the best developed. The eyeballs are large, allowing the retina to capture large images with clear detail. The eye has three eyelids - the upper, lower and transparent inner, or nictitating membrane. Accommodation (focusing the eye) is carried out by changing the shape of the lens and simultaneously changing the distance between the lens and the retina, as well as some changing the curvature of the cornea. All birds have color vision. The visual acuity of birds is several times higher than the visual acuity of humans. This property is associated with the enormous importance of vision during flight.

The hearing organ is anatomically similar to the hearing organ of reptiles and consists of the inner and middle ear. In the inner ear, the cochlea is better developed, and the number of sensitive cells in it is increased. The cavity of the middle ear is large, the only auditory bone - the stapes - is of a more complex shape, it is more mobile when the dome-shaped eardrum vibrates. The eardrum is located deeper than the surface of the skin; a canal leads to it - the external auditory canal. Birds have very acute hearing.

Compared to reptiles, birds have an increased surface area of ​​the nasal cavity and olfactory epithelium. Some birds (ducks, waders, carrion-eating predators, etc.) have a well-developed sense of smell and are used when searching for food. In other birds, the sense of smell is poorly developed.

The taste organs are represented by taste buds in the mucous membrane of the oral cavity, on the tongue and at its base. Many birds distinguish between salty, sweet and bitter.

Reproductive organs. The male has two testes, the vas deferens form a small expansion in the lower part - the seminal vesicle - and flow into the cloaca. The female has only one left ovary and a left oviduct, which flows into the left side of the cloaca. Fertilization is internal and occurs in the initial part of the oviduct. Due to the contraction of the walls of the oviduct, the fertilized egg moves towards the cloaca. In the oviduct there are protein glands and glands that form on the egg a two-layer leathery subshell shell, a porous calcareous shell and a thin supershell shell. The latter protects the egg from microorganisms.

The egg moves through the oviduct for 12-48 hours and is successively covered with a thick albumen, subshell, shell and supra-shell membranes. At this time, the development of the embryo occurs. At the moment the egg is laid, it looks like a germinal disc, which is located on the surface of the yolk. Two convoluted protein cords - chalazae - go from the inner shell to the yolk and support the yolk so that the embryonic disk is on top, closer to the body of the bird that incubates the egg. For egg development, a temperature of 38-39.5 °C is required. The duration of incubation varies among different birds: from 12-14 days for small passerines to 44-45 days for the golden eagle and almost two months for large penguins, albatrosses, and vultures. In different species of birds, the eggs are incubated by the female, the male, or both in turn. Some birds do not incubate eggs: the sandpiper in Turkmenistan buries its eggs in hot sand, the weedy (or big-footed) chickens of Australia and the Malay Archipelago lay them in heaps of sand and rotting plants; during decay, the heat necessary for the development of the embryo is generated.

Most birds incubate their eggs in a nest. Most often, birds build or weave nests from twigs, grass, moss, often fastening them with some additional material (hair, wool, clay, mud, etc.). The nest usually has raised edges and a recessed interior - a tray that holds the eggs and chicks. Thrushes, finches, and goldfinches strengthen their nests in the forks of branches on bushes and trees. In the wren and long-tailed tit, the nest has the form of a dense ball with thick walls and a side entrance, fixed in the fork of the branches. Larks and wagtails make nests on the soil, in a hole lined with grass. Woodpeckers, nuthatches, tits, flycatchers, and whirligigs nest in hollows, kingfishers, bee-eaters, and shore swallows nest in holes along river banks. Many swallows make a nest out of lumps of clay and mud, held together by sticky saliva. Rooks, crows, storks, and many daytime predators build nests from large twigs and branches. Seagulls, guillemots, and loons lay eggs in the sand and in depressions on rock ledges. Female ducks, geese, and eiders pluck the fluff on their abdomen and line their nest with it. Temperature fluctuations in nests are significantly less than in the environment; this improves incubation conditions.

According to the degree of physiological maturity of the chicks at the time of hatching, all birds are divided into two groups - brood and nestlings. In brood birds, immediately after hatching, the chicks are covered with down, sighted, can move around and find food independently. Adult birds protect the brood, periodically warm the chicks (this is especially important in the first days of life), and help in searching for food. This group includes Galliformes (grouse, hazel grouse, pheasants, partridges, quails, chickens), Anseriformes (geese, ducks, swans, eiders), cranes, bustards, ostriches. In nestling birds, the chicks are initially blind, deaf, naked or slightly pubescent, cannot move, and remain in the nest for a long time (in passerines - 10-12 days, in some birds - up to 2 months). All this time, their parents feed and warm them. This group includes pigeons, parrots, passerines, woodpeckers and many others. First, parents feed the chicks soft, nutritious food (for example, tits feed the chicks spiders in the first days). The chicks leave the nest feathered, almost reaching the size of adult birds, but with uncertain flight. For 1-2 weeks after departure, the parents continue to feed them. At the same time, the chicks learn to search for food. Thanks to various forms of caring for their offspring, the fertility of birds is much lower than the fertility of reptiles, amphibians and fish.

Extinct forms and phylogeny. All the features of birds that distinguish them from reptiles are primarily adaptive in nature. It is quite natural to believe that birds evolved from reptiles. Birds originate from the most ancient reptiles - pseudosuchians, whose hind limbs were built in the same way as those of birds. A transitional form - Archeopteryx - in the form of fossil remains (imprints) was discovered in Upper Jurassic deposits. Along with the features characteristic of reptiles, they have the structural features of birds.

Taxonomy. Modern forms of birds are divided into three groups: ratites (South American, African, Australian ostriches and kiwis), penguins and keels; the latter unite a huge number of species. There are about 30 orders of keelbirds. Of these, the most important are passerines, chickens, diurnal predators, Anseriformes, pigeons, etc.

Flights

Sedentary birds live in certain territories throughout the year, for example sparrows, tits, magpies, jays, crows. After the breeding season, nomadic birds make migrations over hundreds of kilometers, but do not leave a certain natural zone, for example, waxwings, bullfinches, redpolls, crossbills, and many owls. Migratory birds regularly fly to wintering grounds thousands of kilometers from their nesting sites along clearly defined flyways to other natural areas.

Migration is a seasonal phenomenon in the life of birds, which arose in the process of evolution under the influence of periodic changes in weather conditions associated with the change of seasons, intensive processes of mountain building over vast areas and sharp cold snaps in the Quaternary period. The long northern day and a large amount of animal and plant food contribute to the feeding of offspring. In the second half of summer in the northern regions, the duration of daylight hours decreases, the amount of animal food (especially insects) decreases, the conditions for its production worsen, the birds' metabolic patterns change, which, with increased nutrition, leads to the accumulation of fat reserves (in American tree warblers before flying over sea ​​fat reserves account for up to 35% of the mass of birds). Many birds begin to unite in flocks and migrate to wintering areas. During migrations, birds fly at normal speeds, small passerines move 50-100 km per day, ducks - 100-500 km. The migrations of most birds take place at an altitude of 450-750 m. In the mountains, flocks of flying cranes, waders, and geese were observed at an altitude of 6-9 km.

Migration in some species occurs during the day, in others at night. The flight alternates with stops for rest and feeding. Migrating birds are capable of celestial navigation, i.e. to select the desired flight direction based on the position of the sun, moon and stars. The selected correct general direction of flight is adjusted according to visual landmarks: when flying, birds adhere to river beds, forests, etc. The direction and speed of migrations, wintering places and a number of other characteristics of birds are studied using their mass ringing. Every year, about 1 million birds are ringed in the world, including about 100 thousand in the USSR. A light metal ring with the number and symbol of the institution that carried out the ringing is put on the bird’s leg. When a ringed bird is caught, the ring is removed and sent to Moscow to the Ringing Center of the USSR Academy of Sciences.

The meaning of birds

Birds are of great economic importance, as they are a source of meat, eggs, down, and feathers. They destroy pests of fields, forests, orchards and vegetable gardens. Many species of domestic and wild birds suffer from psittacosis, a viral disease that can also infect humans. Birds living in the taiga, along with mammals, represent a natural reservoir of the taiga encephalitis virus. Birds living in Central Asia, along with mammals and reptiles, can be a natural reservoir of tick-borne relapsing fever pathogens.

However, not a single bird can be considered only useful or only harmful; it all depends on the circumstances and time of year. For example, sparrows and some granivorous birds feed on the seeds of cultivated plants and can peck juicy fruits in gardens (cherries, cherries, mulberries), but feed their chicks on insects. Feeding chicks requires a particularly large amount of food. The great tit brings food to the chicks up to 400 times a day, while destroying up to 6 thousand insects. The pied flycatcher collects 1-1.5 kg of insects, preferably small caterpillars, to feed six chicks over 15 days. During the autumn migration, the blackbird destroys a lot of blackbird bugs in forest belts and bushes: blackbird bugs during this period make up up to 74% of the total number of insects in the stomachs of blackbirds. Especially many harmful insects on agricultural crops and in forest plantations are destroyed by tits, flycatchers, nightingales, swallows, nuthatches, swifts, shrikes, starlings, rooks, woodpeckers, etc. Insectivorous birds eat many mosquitoes, midges, and flies that carry pathogens. Many birds (larks, pigeons, tap dancers, goldfinches, partridges, quails, bullfinches, etc.) feed on weed seeds, clearing fields of them. Birds of prey - eagles, buzzards, falcons (falcons, saker falcons, kestrels), some harriers, as well as owls destroy large numbers of mouse-like rodents, some feed on carrion and, thus, are of no small sanitary importance.

Under certain conditions, some bird species can be harmful. In particular, the bee-eater near apiaries feeds on bees, but in other places it destroys many harmful insects. The hooded crow eats the eggs and chicks of small birds, but also feeds on insects, rodents, and carrion. The goshawk, sparrowhawk, and marsh harrier destroy a large number of birds, in particular, the marsh harrier - chicks of waterfowl. One rook eats more than 8 thousand larvae of cockchafers, click beetles, and beet weevils per season, but in the spring, rooks pull out seedlings of corn and some other crops, so crops have to be protected from them.

Bird strikes sometimes cause serious accidents in jet and propeller-driven aircraft. In the areas of airfields, birds have to be scared away (in particular, by broadcasting recorded distress calls or alarm calls).

By making transcontinental flights, birds contribute to the spread of pathogens of certain viral diseases (for example, influenza, ornithosis, encephalitis, etc.). However, most birds can be considered beneficial. Many birds serve as objects of sport or commercial hunting. Spring and autumn hunting is permitted for hazel grouse, wood grouse, black grouse, pheasants, partridges, ducks and other birds. On the islands and coasts of the Arctic Ocean, light and warm eider down is collected, which eiders use to line their nests. Down is used to insulate the clothing of pilots and polar explorers.

Poultry farming

Poultry farming is an important branch of agriculture, developing rapidly. Chickens are bred at poultry factories and poultry farms (egg-laying breeds - Leghorn, Russian White, Oryol; egg-meat breeds - Zagorsk, Leningrad, Moscow), geese, ducks, and turkeys. Tens of thousands of eggs are laid in incubators at a time. Feeding, collecting eggs, maintaining the required temperature and light, cleaning processes, etc. mechanized and automated.

Bird conservation

To increase the number of beneficial birds, it is necessary to create favorable conditions for their nesting, for example, mixed forest plantations with a varied shrubby undergrowth, planting clumps of shrubs in parks and gardens. By hanging artificial nesting boxes (birdhouses, nest boxes, etc.), you can increase the number of tits, flycatchers, starlings and other birds by 10-25 times. In winter, it is recommended to feed sedentary birds by installing feeders on window sills, in front gardens, gardens, and parks. You should not disturb birds during the nesting period, destroy nests or collect eggs. During the hatching period, bird hunting is prohibited. Birds should also be protected in their wintering areas. State reserves and sanctuaries are of great importance in the protection of birds. For some rare and endangered bird species (for example, the white crane, etc.), measures are being developed for artificial maintenance and breeding in nature reserves.