Abstract: Class Birds. Class Birds (Feathered) 2 species of birds

For the full cycle of life on our planet, the presence of birds - predators in nature is an obvious necessity.

Different species of birds have a natural habit of hunting large prey. Among them: hawks, representatives of eagle and falcon orders, gulls, owls and others. The unifying criteria for these species are:

• the role played in the natural chain;
• way of eating;
• lifestyle (time of day at which the bird starts hunting).

Daytime birds of prey

According to the systematization from the point of view of zoology, only falconifers belong to the orders of daytime birds of prey, these are falcons themselves, hawks, eagles, buzzards, eagles, harriers.

It is noteworthy that truly birds of prey have the same menacing and dangerous appearance: the beak is bent like a hook, and their claws are crooked and very sharp. The coloration of females and males is almost identical, but females are larger in size.

Upland Buzzard

Another name is Rough-legged Buzzard. This bird is considered the most famous predator among the tundra forests. She builds her nests throughout the entire Yamalo-Nenets Autonomous Okrug... The food of this predatory species is made up of mice - voles and lemmings. It is characteristic that the number of buzzards directly depends on the sufficient population of the area with these rodents. Scientists - ornithologists argue that in the conditions of one area, buzzards may be present in abundance, or they are not at all.

External signs of the Upland Buzzard:

• rough legged large bird in size;
• has wide wings (this visually makes it even larger);
• general color - light, slightly “red”;
• on the belly and under the wings of the predator, black spots are localized, different in shape (they can form an individual plumage pattern).

Buzzards nest in woody areas, and they line the nests with grass. If we are talking about the tundra, then in these areas birds are usually located on cliffs and hills. In the case of a fruitful year for mice, the nest of the Rough-legged Buzzard can also be found on flat terrain, in swamps, in the lowlands of rivers.

Buzzards are migratory birds that migrate from warm areas in early spring. After the flight, they begin to build their nests. Upline Buzzard Egg Size larger in size than chicken eggs, rounder in shape, spotty and white in color. The richer the year for prey, the more eggs in the clutch of this bird of prey. The principle of natural selection plays a significant role in the survival of chicks, especially when food is scarce, due to the poor harvest for rodents. Many chicks do not even have the opportunity to live to the "flight" age, they are simply eaten by older and stronger chicks.

Buzzards zealously defend their nests. Attacks on humans are unlikely, more often birds just scream loudly or rush at a person. But from arctic foxes or dogs, they fearlessly fight back, using strong claws. It happens that the Rough-legged Buzzard feeds on dead deer carcasses and their entrails, or on rotten fish.

With the arrival of the autumn period, and during its duration, these predators fly away to the areas of the middle lane.

White tailed eagle

It is one of the largest and largest birds of prey in Russia. His wingspan exceeds two meters, and the weight of the bird sometimes reaches seven kilograms. The owners of a pure white tail are predominantly adults, whose age is more than three years, in the rest it is dark. Often a young eagle can be mistaken for a golden eagle. However, the tail of the golden eagle is slightly rounded, while in the white-tailed it has the shape of a sharp wedge.

White-tailed eagles nest almost throughout the country, they only avoid the extreme northern areas and dehydrated areas. They arrange their nests only in the crowns of trees, more often deciduous ones. Very rarely, the "eagle house" is located on steep cliffs.

White-tails feed on fish and birds floating in the water. This explains their desire to live near areas rich in water bodies. Every year their dwelling is located in the same place, has a very massive, layered structure up to a meter in height. On the open tundra expanses, the eagle's nest is extremely rare, more often it localized on hills or cliffs.

During early spring, eagles already arrive from the south. The flight is carried out in pairs that are notable for constancy. Females lay from one to three eggs in the newly inhabited nest. The eggs are white with spots, similar in size to those of a goose, but somewhat smaller. After the first egg has been laid, female eagles begin hatching. Chicks emerge from the egg around the first half of June. Their growth is very rapid, plumage is fast.

In early August, the chicks fly out of the nest, however, for a long time they are under the supervision of their parents. White-tails keep their way to the southern edges in early autumn.

White-tailed eagles feed on wild birds: geese, ducks, loons; also their diet consists of hares, large fish species, rodents. Moreover, these birds of prey are lovers of carrion, or they hunt animals that are injured or sick and cannot resist.

White-tailed eagles are rare, valuable birds, they are listed in the Red Book of both our country and the international one. Often the eagle falls prey to hunters - poachers, which is very sad for nature and scientists.

Osprey

These birds of prey are small in number, are considered rare, and are listed on the pages of our Red Book.

Species characteristics:

• large size;
• contrasting color: white-yellow underside of the body; a dark stripe running across the bird's craw; from above the body, tail and wings are dark in color; there are wide black stripes on the head;
• yellow eye color;
• in conditions of increased anxiety, these birds emit peculiar sounds.

The habitat of these predators is the territory of the whole world, with the exception of the extreme northern regions. They hibernate in the African and South Asian tropics.

Osprey are chosen to provide the necessary living conditions, areas with clean waters rich in fish... They nest in tall trees, with dry tops, away from crowded places. Birds do not change their nests, returning to them annually. Osprey clutch contains up to four eggs maximum, usually two or three. The eggs are dark in color, with purple spots of various localization.

Chicks live in the nest for about two months without leaving it. They become sexually mature when they reach the age of two.

The peculiarities of the hunting of these birds of prey are that they, flying high above the water surface, hunt down their main food - fish. Having spotted the victim, the osprey dives forward with its paws, and then takes off sharply, catching the victim. This bird disdains carrion, if hunger begins to exhaust, then the predator can arrange a hunt for ducks or mice.

The osprey goes to winter from September to October.

The number of this species is inexorably decreasing due to the direct extermination of predators, unfavorable ecology, and deforestation. All this makes it impossible for birds to nest safely.

Goshawk (hawk)

The size of the bird is larger than the crow, weight up to one and a half kilograms

Character traits:

• clear stripes running across the underside of the bird's body;
• dark gray upper body;
• very bright yellow eyes;
• young goshaws are colored red or brown.

Birds of this species were persecuted for a very long time due to the fact that they were considered predators, bringing special harm. As a result, their numbers have fallen, and now they are protected by law.

Hawks - goshaws feed on medium-sized fish and small animals such as rabbits, squirrels, and so on. They hunt dying animals that are doomed and weakened by illness or injury. Thanks to this, predators are ranked among forest orderlies.

Goshawk distribution zone - north of the forest-tundra... They winter either where they nest or fly away to where it is warmer.

Field harrier

It is a bird that lives, more often, in open spaces - forest-tundra zones, forest-steppe and taiga belts. The main habitat is the abundance of small rodents.

Harrier is about the size of a crow, but with a longer tail and slender body. The colors of the male and female are different.

Features of the male color:

1. white body with an ash coating on top;
2. the ends of the wings have black streaks.

Female color:

1. the body is reddish with gray;
2. the lumbar region is white.

Field Harriers build their nests on the surface of the earth. The clutch contains from three to five white, slightly spotted, eggs. They are smaller than chicken eggs, the most round.

The harrier is a migratory bird. It hunts, flying not very high above the ground.

Peregrine falcon

The most famous falcon. It is a rare and valuable bird breed. Unfortunately, poachers are especially fond of catching these particular predators, as a result of which their fate is extremely sad. Peregrine falcons are practically exterminated, they are very rare even in uninhabited areas.

In the United States, in order to restore the number of these birds, their kept in specialized enclosures... Peregrine falcon chicks are raised and then released to free latitudes. However, even taking into account the usefulness and importance of these activities, it should be said that they are very costly in material terms. Falcons set free are of great monetary value.

The peculiarity and pride of the peregrine falcon are clear, piercing black eyes, above which black eyebrows loom. No wonder in Russia the heroes were often called "clear falcons".

Within the Yamal territory, the falcon population is no more than two hundred pairs of these birds of prey. The part of Russia most populated by falcons is the West Siberian tundra area, where the situation with predators is quite stable.

External characteristics of a peregrine falcon:

The falcon, by right, is ranked among the fastest living creatures on the planet, and even among birds it has no equal. He hunts, attacking the victim from above, in a steep "dive". Small birds, peregrine falcon grabs with strong paws, and larger ones, at speed knocks down with sharp claws on the hind fingers. Then the ravenous falcon grabs the falling prey on the fly.

Peregrine falcons often bring their prey from places far from the nest. Previously, it was believed that they did not hunt near their nests, however, observations showed the opposite. There are frequent cases of the falcon hunting near the nesting female.

Predators of this species very zealously and aggressively defend their nest. Noticing the danger, the peregrine falcon raises a frantic cry, and, diving, attacks the uninvited guest. A little later, the female joins the male. Falcons also attack people, but with the aim of simply scaring them without touching them.

The peregrine falcon is a sophisticated hunter. Among its victims, one can designate entire collections of the rarest birds, the existence of which even ornithologists do not always know.

Falcons nest, choosing a variety of places for this. It can be rocks, alien, abandoned nests, even hollows of trees or just plain land. An important condition for nesting is the ability to have a good view of the area. The number of clutches is from three to five eggs. They are similar in size to chicken.

Tellingly, the grown chicks do not eat small falcons, in contrast to the buzzards. This is considered a noble feature of this bird species. However, it is fair to say that their number is absolutely independent of the harvest for rodents, which means that the peregrine falcon with chicks will not die of hunger for sure.

Falcons are migratory, not flocking birdsleading a solitary lifestyle. One pair of peregrine falcons builds a nest far from the other. The pairs are constant, stable. However, their nests are always in the same place. Predators arrive in early spring, and fly away at about the same time as other birds.

Derbnik

It is considered the smallest falcon in size. The Nesting Territory of this predator is vast, but merlin avoids too northern areas. This type of predator is quite rare.

The type of food of merlins is small birds caught and captured on the fly. They make their nests mainly in trees, in abandoned crow's nests. The number of eggs hatched up to five pieces. Both females and males act as brooders, but the former are more involved.

It is noteworthy that the merlin is about the size of a pigeon. But at the same time it is a worthy predator in the tundra and its forests. This bird is protected by law.

Owls are nocturnal predators. These are well-known birds that have been repeatedly mentioned in children's fairy tales.

Features of the appearance of an owl:

Owls exterminate various rodents, while bringing great benefits to people. Therefore, they are protected by law from poachers and simply those who like to make fun of living beings.

Polar owl (or white)

A very colorful nocturnal predator that lives in the steppes and forests of the tundra. It hunts for voles, partridges, hamsters - lemmings... Sometimes they catch hares and even polar foxes and ermines.

Small peoples of the north often used owl meat for food, for this purpose they hunted it.

Short-eared owl

It is inferior in size to the polar one. It also feeds on rodents and lives in tundra areas. There were cases when a short-eared owl was seen over the sea.

There are also other types of owls, for example: Lapland, hawk, eagle owl.

It is noteworthy that the tawny owl is a daytime predator, even somewhat similar to a falcon.

Owls are the largest birds of the owl order. They have ears on the head, the color is variegated with red. An eagle owl can attack a buzzard or a hawk, but mainly its food consists of rodents and small animals.

In the north, the owl can hunt during the day.

Hibernating birds are those that stay in their native land all year round. Animals are guided not so much by the air temperature as by their personal abilities and the specifics of the food supply in the region.

Warmth in cold weather is only for well-fed birds. This means that a wintering bird should be able to get food among the snow. Accordingly, insectivorous species fly away in winter. Remain content with berries, seeds and predators hunting mice and hares. There are about 70 wintering bird species in Russia.

Dove

Their body temperature, like other birds, is 41 degrees. This is one more proof that in the presence of food, feathered frosts do not care. not easy wintering birds, but "tied" to a specific place. Flying away from the "native nest" for thousands of kilometers, gray-gray always come back. People took advantage of this by starting to send letters with pigeons.

Taking them to the addressee, the birds returned. Scientists argue about how birds find their way home. Some refer to magnetic fields. Others believe that pigeons are guided by the stars. Doves are faithful not only to their native lands, but also to partners. A pair of birds is chosen once and for life, like swans.

Pigeons are very attached to habitats and do not leave them if they have food

Sparrow

Group of wintering birds consists of several types. There are two living in Russia: urban and field. The latter is typical for rural areas. The total number on the planet is close to a billion. Accordingly, one bird for 8 people.

Considering that birds feed on grains, this is a threat to the harvest. In the PRC, they even carried out an action to destroy sparrows. Having found out that they cannot fly for more than 15 minutes, people frightened the birds, not allowing them to descend to the ground. Approximately 2 million individuals fell dead. However, in the absence of sparrows, it bred - another delicacy for birds. She ate the harvest instead of the birds.

Like pigeons, sparrows tend to choose one partner for life. At the same time, birds have hot blood. Instead of 41 degrees, the sparrow's body heats up to 44 ex. This is typical of small birds. They lose energy faster. Interestingly, the sparrow has 2 times more vertebrae in the neck than the giraffe. It's about the length of the fragments. In sparrows, they are flat.

Crossbill

This bird of the finch family with a curved, curved beak. Its structure is determined by function. The crossbill picks up grains from the cones with its beak. At the same time, a characteristic click is heard. Hence and name of wintering birds.

Despite the adaptability of the beak, it is impossible to take out all the pine nuts. The cones thrown by the birds are cleaned. The males of the species are red-brown and the females are gray-green-yellow. Birds become such by 3 years of age. As adults, the crossbills do not exceed 20 centimeters in length and weigh about 50 grams.

The intelligence of ravens, by the way, is comparable to the development of 5-year-old children. Birds solve the same logic problems. One of the indicators of the mind is the way of protecting the nests. Ravens throw stones at enemies, raising them in tenacious paws.

In food, birds are unpretentious, they absorb grains, vegetables, and bread. The birds often destroy the nests of other birds. But, the ravens' favorite delicacy is carrion. There is a lot of it in winter, because not all animals can withstand the cold. Here birdsand remain to winter.

In years poor for prey, snowy owls migrate to the forest-steppe zone. The bird is large, up to 70 centimeters in length. The feathered one is gaining 3 pounds. Harry Potter held about as much on his hand. The hero of the work, J.K. Rowling, often used the services of Buckley. That was the name of the white owl, who served as a messenger for the wizard.

Nutcracker

The bird feeds on pine nuts. For them, the bird has a hyoid sac. It carries about 100 nuts. The Russian taiga is rich in cedar, which means that the bird has no need to fly away in winter. Some of the cones remain on the trees in winter.

We hide nutcracker nuts that do not fit into the hyoid sac within a radius of 2-4 kilometers from the tree on which they ripened. In winter, reserves are buried in snowdrifts, and in summer in the ground. There is a monument to the nutcracker in Russia. He stands in Tomsk. The Siberian city is surrounded by cedars. The inhabitants of the region know and love their inhabitant, admiring her all year round.

Owl

Listed in Red. The bird easily endures Russian winters, but cannot adapt to the reduction due to the destruction of the taiga of its fiefdom. However, owls are capable of living in captivity. In zoos and private owners, birds lived to be 68 years old. In nature, the eagle owl's age is limited to 20 years. Like the white owl, it hunts rodents, hares, martens.

Birds catch them around the clock. The main activity is at night. Eagle owls sleep more often during the day. Eagle owls swallow small prey whole. The birds first tear large victims into pieces that can squeeze into the throat. Cases of eagle owls attacking young roe deer and wild boars have been recorded. This indicates the impressive size of the birds.

Nuthatch

The bird has a bluish back and white belly. The feathered sides are red with black stripes. On the paws - curved sharp claws. With them nuthatches dig into tree trunks, moving quickly and dexterously along them. The bird is looking for hidden insects, their larvae. A sharp, long beak allows the nuthatch to get them in winter. The bird studies every crack in the bark with it.

They prefer to settle in oak forests. Where oaks do not grow, birds choose parks with deciduous plantings. Nuthatches are looking for trees with hollows, settling in them. If the entrance to the house is wide, it is coated with clay. Nuthatches are engaged in this work in the warm season.

Nuthatches prefer to survive the cold by settling in the hollows of trees

Yellow-headed beetle

Only hummingbirds are smaller than him. The bird has a yellow crest resembling a crown on its head. This association prompted the name feathered. The king does not pull, because the size of a dragonfly. The weight of the bird is about 7 grams.

They live in coniferous forests. Unlike hummingbirds, Russian dwarfs among birds endure a harsh climate. Even in winter, beetles manage to find insects and their larvae. On the day, the bird eats as much edible as it weighs itself.

Chizh

It is considered migratory. However, some of the siskins remain for the winter in Russia. Birds are ready to survive the winter here next to non-freezing water bodies. The birds arrange their nests in the roots of trees near them.

Small birds so skillfully camouflage their homes that they became heroes of the legend of the invisible stone. Our ancestors believed that such a crystal was placed under the nest, hiding it from prying eyes.

Winterers include grouse and partridges. They warm themselves by burying themselves in drifts. Under the snow, the birds are looking for food - last year's grains and herbs.

Black grouse uses snow as a warm overnight

In severe frosts, birds try to avoid flying. The body area that increases with the wings open leads to a greater heat loss. The feathered one runs the risk of freezing instead of catching prey or getting to places with better weather.

Wintering birds of Russia

Let us consider in more detail the species of birds that remain to winter in Russia.

Since not all types are listed in the picture above wintering birds of Russia, for the sake of completeness, let's call them: Sparrow, Crows, Dove, Woodpecker, Nutcracker, Crossbill, Yellow-headed Kinglet, Partridge, Muscovy, Owl, Nuthatch, Grouse, Waxwing, Tit, Bullfinch, White owl, Jay, Magpie, Grouse, Eagle owl , Lentils, Siskin, Goldfinch, Schur.

Birds are vertebrates adapted to flight, their forelimbs are turned into wings, the body is covered with feathers, and have a streamlined body shape. There are more than 9000 living species. Birds live in virtually all climatic zones and occupy various ecological niches.

Compared to reptiles, a number of large aromorphoses occurred in birds, which allowed them to become more active and less dependent on environmental conditions. This is the emergence of thermoregulation (warm-bloodedness), complete separation of venous and arterial blood flow, the emergence of a four-chambered heart. Other multiple adaptations of birds are more appropriate to consider as adaptations to flight.

Feather cover of birds

The feather cover of birds evolved from the horny scales of reptiles. Each feather develops in a feather bag, in which the lower end of the feather (quill) remains, through which the feather is fed.

In the plume, the trunk and the fan are distinguished. The fan consists of horny barbs of the first order and those extending from them of the second order. Second-order barbs have hooks that engage adjacent second-order barbs. Thus, the fan becomes monolithic, does not allow air flows through itself, which plays an important role in the ability of birds to fly.

The feather cover of birds does not grow over their entire body, but only in the so-called pterilia... IN pharmacies feathers do not grow, but they are covered with feathers that have grown in the pterilia. In birds, only the lower part of the legs and beak are not covered with feathers (in some species, also the neck).

Bird feathers are not the same. Distinguish between contour feathers, down feathers, down, etc. Contour feathers are cover, steering (located on the tail), flight feathers (on the wings). Flight and tail feathers are essential for flight. Down serves as thermal insulation.

For birds, molt is characteristic when the feather cover is replaced. In some species, this happens in such a way that they immediately lose almost all of the old feathers. In others, molting occurs gradually.

The skin of birds is dry, thin. They have a single gland - the coccygeal gland. Well developed in waterfowl. Birds lubricate feathers with its fatty secretion, which prevents them from getting wet.

The musculoskeletal system of birds

The musculoskeletal system of birds undergoes a number of significant changes associated with flight. This applies to both the skeleton and the muscular system.

Bird bones become lighter, many have cavities. Many of the bones in the skeleton grow together to provide additional strength during flight.

The bird's skull is robust with large eye sockets. The beak is formed by jaws covered with horny sheaths ( beak and mandible). The beak of different species of birds is adapted to obtaining and processing certain types of food. All birds have missing teeth.

The cervical spine is highly mobile. The number of vertebrae depends on the species of bird. The thoracic vertebrae grow together. The lumbar, sacral and first caudal vertebrae also grow together, forming complex sacrum, giving powerful support to the pelvic girdle and hind limbs. The last caudal vertebrae also fuse, tail feathers are attached to them.

The ribs extend from the thoracic vertebrae. Each rib of the bird consists of an upper and lower part, movably connected to each other. The lower parts of the ribs are attached to a fairly large sternum. The ribs of birds have hook-shaped processes. The vast majority of birds move away from the sternum keel, to which are attached powerful muscles that ensure the raising and lowering of the wings in flight.

The shoulder girdle of birds consists of elongated shoulder blades (lying along the spine), powerful coracoids (connected to the beginning of the sternum) and collarbones. The clavicles grow together and form fork, which plays the role of a kind of spacer when the wings move. The bones of the forelimbs are homologous to those of reptiles. The humerus, ulna and radius are preserved in the wing of birds. However, a number of bones in the wrist and metacarpus grow together to form buckle... The fingers on the wings of birds are reduced, only three remain, of which only one is well developed.

The bones of the pelvic girdle (iliac, sciatic and pubic) are spliced \u200b\u200btogether on each side and are motionlessly accreted to the complex sacrum. Both pubic bones do not fuse together. Also, the ischial bones do not grow together. This makes the pelvis of the bird open, which makes it possible to lay large eggs. The skeleton of the hind limb consists of the femur, the bones of the lower leg, tarsus, fingers (usually four, three of which are turned forward). The tarsus is formed by a series of bones in the tarsus and metatarsus.

The muscles of birds are more differentiated than those of reptiles. In addition, in a number of departments, the muscular system is very powerful. So in birds, the pectoral and subclavian muscles are highly developed, which are responsible for raising and lowering the wings. The muscles of the neck and tail are well developed.

Respiratory system of birds

The respiratory system of birds is in many ways unique, they are characterized by the so-called double breathing... With it, fresh air passes through the lungs both during inhalation and exhalation. To carry out such breathing, birds have air bags (several pairs can also be unpaired).

On inhalation, air enters the lungs and back air sacs. On exhalation, air from the lungs predominantly passes into the front air sacs, and enters the lungs from the rear. From the anterior sacs, air is removed through the trachea.

The lungs of birds are dense, spongy tissue that increases their surface.

Air bags filled with air reduce the density of the bird's body, making it lighter.

At rest, birds breathe due to the expansion and contraction of the pectoral muscles. In flight, the bird's chest remains almost motionless and provides additional support for the wings. Therefore, the expansion and contraction of the air sacs occurs due to the movement of the wings. Moreover, the more often and more powerfully the flapping of the wings, the more often the birds breathe, and the more their air sacs are filled with air.

The circulatory system of birds

In the circulatory system of birds, venous and arterial blood do not mix. Unlike reptiles in birds, only one (right) aorta emerges from the left ventricle of the heart.

The heart is four-chambered. The right atrium and ventricle contain only venous blood. Left - only arterial. The systemic circulation begins in the left ventricle and ends in the right atrium. The small (pulmonary) circle of blood circulation begins in the right ventricle and ends in the left atrium.

The large heart of birds beats often, very often in flight (hundreds of times per minute).

Digestive system of birds

Fast digestion is characteristic of birds. For many, food passes through their digestive tract in less than an hour.

In many birds, the esophagus has an expansion (goiter), where swallowed food is temporarily deposited. There are salivary glands.

A feature of the digestive system of birds is the presence of two stomachs. In the first (glandular), enzymatic processing of food takes place. In the second (muscular), food is rubbed both by the powerful walls of the stomach and by swallowed stones.

The large intestine in birds is short, it opens into the cloaca, the rectum is absent. Thus, the remains are not retained in the body, which makes it easier for the bird to fly.

Excretory system of birds

The main product of excretion in birds is uric acid, as in reptiles. It requires little water to release it. Removal of harmful substances from the body occurs quickly, which is associated with an intensive metabolism.

Birds have large enough kidneys, the ureters open directly into the cloaca. The bladder is missing.

The nervous system and sensory organs of birds

In the nervous system of birds, a stronger development of the forebrain hemispheres occurs (they are responsible for complex behavior and the development of conditioned reflexes), the midbrain also increases (associated with the improvement of vision) and the cerebellum (is responsible for coordination of movements, which is of great importance for birds in connection with flight ).

The main sense organ of birds is vision. This is due to the fact that when flying, you need to see objects from a distant distance, birds clearly distinguish colors and their shades. There are more sensitive cells in the eyes of birds than in mammals.

Hearing is also important in the life of birds. In a number of birds (for example, owls), it is very thin, it allows you to catch the sounds made by prey at night.

The vast majority of birds have poor sense of smell.

Reproduction and development of birds

A pair of testes functions as reproductive organs in male birds. During the breeding season, they greatly increase. Through the vas deferens, sperm enters the cloaca and is subsequently injected into the female's cloaca. Birds only have internal fertilization.

Females retain only one ovary. This is due to the formation of large eggs (containing a large amount of yolk), which turn into large eggs in the genital tract of the female. Two such eggs could not pass through the pelvis of a bird.

Fertilization of the egg takes place at the top of the oviduct. Moving to the cloaca, the egg is covered with shells: protein (contains a large supply of water), two shells, a shell (lime is later partially used to form the skeleton), an overshell shell. The duration of egg formation is different for different bird species. On average, about a day.

An embryonic disc is formed on the surface of the yolk by crushing. The yolk is suspended in the egg on protein threads - chalases.

One of the manifestations of the complex behavior of birds is the expressed concern for the offspring. The birds incubate the clutch, after hatching the chicks take care of them for a long time. Chicks are of two types: brood and nest. The first ones, almost immediately after hatching, are able to follow their parents and feed on their own. When they hatch, they are already covered with down. Breeding chicks appear naked, blind and helpless. The parents feed them in the nest.

Bird ecology

The high metabolic rate due to the improvement, first of all, of the circulatory, respiratory and digestive systems led to the warm-bloodedness of birds (the ability to maintain a constant body temperature). This resulted in less dependence on environmental conditions than in reptiles. Birds are widely spread across the Earth; they are found in Antarctica as well.

Birds are characterized by seasonal migrations associated with moving to the best places for feeding, breeding, and avoiding unfavorable conditions. Allocate sedentary, nomadic and migratory birds... Sedentary birds usually live all year round in the same place. Wandering birds fly hundreds of kilometers in the post-nesting period. Migratory birds fly thousands and tens of thousands of kilometers. Usually they fly away for the winter to places where there is no severe cold (for example, from Europe to Africa).

There are three large groups of birds: typical birds, penguins and ostriches. Representatives of the last two do not fly. Ostrich species are the largest living birds. Penguins are adapted to swimming. The vast majority of typical birds fly. They are the most numerous and diverse (more than 20 orders).

There are various ecological groups of birds by habitats (birds of the forest, open spaces, waterfowl, living near water bodies), nesting sites (in crowns, shrubs, ground, nesting in hollows, etc.), type of food (herbivores, insectivores, carnivores, scavengers, omnivores), etc.

It includes a number of extinct species, as well as 5 living orders, including:

Order Cassowary (Cassowary and Emu)

Cassowaries and emus from the order of cassowary, or Australian ostriches ( Casuariiformes)are large, flightless birds with long necks and legs. They have long feathers that resemble rough fur, but the head and neck are almost bald.

There are four species of cassowary that have survived to days:

• Helmet Cassowary ( Casuarius casuarius);
• Orange-necked cassowary ( C. unappendiculatus);
• Cassowary-muruk ( C. bennetti);
• Emu ( Dromaius novaehollandiae).

Order Kiwiformes (Kiwi)

Experts disagree on the exact number of species belonging to the kiwiformes ( Apterygiformes), but there are at least three: southern kiwi, large gray kiwi, and small gray kiwi. According to the latest data, scientists have identified two more species: the northern brown kiwi and Apteryx rowi.

Birds from this order are endemic to New Zealand. Kiwis are flightless birds with tiny, almost rudimentary wings. They are strictly birds, digging out larvae and earthworms at night with the help of their long, narrow beaks.

New Zealand's national bird, the kiwi, is vulnerable to dogs, which were introduced to these islands hundreds of years ago by European settlers.

Detachment Rhea (Nandu)

There are only two species of rhea in the rhea order ( Rheiformes), both of which live in, and the steppes of South America. These flightless birds have long feathers and three toes on each leg; they also have claws on each wing that are used when defending.

Nandu are similar to ostriches in appearance, however, among scientists, the degree of their relationship remains controversial. The body size of the rhea is almost half that of the ostriches.

Order Ostrich (Ostriches)

The only surviving representative of the order of ostrich-like ( Struthioniformes) - African ostrich ( Struthio camelus), which is considered a real record holder. Not only is it the tallest and heaviest living bird, the ostrich can still reach speeds of up to 70 km / h, as well as run long distances at speeds up to 50 km / h. Ostriches have the largest eyes of any vertebrate, and their eggs, weighing up to 2 kg, are the largest among modern birds.

Subclass Newweal

Newneal (Neognathae)birds have a much longer history that reaches the Mesozoic era and this subclass includes 25 orders, such as:

Order Storks, or Ankles (Storks, herons, ibises, etc.)

The order of birds is stork-like, or ankle ( Ciconiiformes) includes herons, storks, ibises and others, more than 100 species in total. All these birds are long-legged, sharp-billed carnivores that live in wetlands. Their long, flexible fingers have no webbing, which allows them to stand in thick mud and not drown. Most are solitary hunters, slowly chasing their prey before swiftly striking with their powerful beaks; they feed on fish, amphibians and insects.

The earliest known ancestors of today's herons, storks and their relatives date back to the late era, about 40 million years ago. The closest living relatives are flamingos.

Order Petrels (Albatrosses and petrels)

Albatross

Birds in the order are petrels ( Procellariiformes), also known as tube-nosed, include over 125 living species, placed in four extant families:

• Petrel ( Procellariidae);
• Albatross ( Diomedeidae);
• Stormflower ( Hydrobatidae);
• Diving petrels ( Procellariidae).

These birds spend most of their time at sea, flying above the water and diving into it to catch fish and other small ones. The tube-nosed birds are colonial birds that only return to the ground to breed (breeding sites vary in species, but generally prefer remote islands and rugged coastal cliffs), are monogamous and form long-term bonds between mating pairs.

The largest species of the order is wandering albatrosses, whose wingspan reaches 3.25 m. The smallest species is Halocyptena microsoma - has a wingspan of less than 30 cm.

Order Sparrow-like (Sparrows, starlings, crows, etc.)

A detachment of passerines ( Passeriformes), represent the most diverse group of birds, consisting of over 5,000 species, including: sparrows, finches, thrush, starlings, crows, swallows, larks and many others. These birds have a unique leg structure that allows them to grasp tightly thin twigs, reeds and fragile stems of grass; some species can even hold onto vertical surfaces, including hillsides and tree trunks.

In addition to the unique leg structure, passerines are distinguished by their complex vocalizations. Although these are not the only birds that can make sounds with the help of the syrinx, this organ is most developed in passerines. Each member of the squad has unique sounds, some of them simple, others long and complex. Some species learn vocalizations from their parents, while others are born with the innate ability to sing.

Detachment Loons (Loons)

A detachment of birds ( Gaviiformes) includes five live types of loons: red-throated loons, black-throated loons,
white-necked loons, black-billed loons and white-billed loons. Loons are freshwater waterfowl common in northern parts and Eurasia. Legs located behind their bodies provide the bird with strength in the water, but make these birds awkward on land. Gaviiformes have fully webbed feet, elongated bodies, and dagger-like beaks that are good for capturing fish and other aquatic invertebrates.

These birds go to land to nest and build their nests close to water. Both parents care for the chicks, which sit on the adults' backs for protection until they are ready for independent living.

Order Pigeon-like (Doves and Turtle Doves)

Detachment dove-like ( Columbiformes) includes over 300 species of pigeons, including doves, wood pigeons, turtledoves, ringed doves, crowned pigeons, and others. Pigeons are small to medium sized birds characterized by short legs, purple coloration, short necks and small heads. Pigeons are equipped with short beaks that are hard at the tip, but softer at the base.

These birds are common in meadows, fields, deserts, farmlands and cities. They also, to a lesser extent, inhabit and as well.

Detachment Anseriformes (Ducks, geese, swans, etc.)

Bird squad of anseriformes ( Anseriformes) includes ducks, geese, swans, etc., which, as a rule, are somewhat irritable due to loud cries. There are about 150 living species in this order. Most prefer freshwater habitats such as lakes, streams and ponds, but some of them live in marine regions at least during the breeding season.

All anseriformes are equipped with webbed feet, which allow them to move more easily through the water. However, you may be surprised to learn that most of these birds are exclusively herbivores; only a few species feed on insects, molluscs, plankton, fish and crustaceans. Anseriformes often find themselves on the other side not only because of people who love their meat, but also because of coyotes, foxes, raccoons and even striped skunks.

Order Woodpeckers (Woodpeckers, toucans, etc.)

To the group of woodpeckers ( Piciformes) includes woodpeckers, toucans, puffs, nonnula, nuns, brachygalbs, yakamars, honey guides, etc., about 400 species in total. These birds love to nest in trees; and the most famous birds of the squad Piciformes- woodpeckers - tirelessly gouge holes in the trunks with their beaks. Some species are antisocial, showing aggression towards other species or even their birds, while others live well in large groups.

Due to the structure of their paws, oti can easily climb tree trunks. Many Piciformes they also have strong legs and sturdy tails, as well as thick skulls that protect their brains from the effects of gouging wood. Beak shapes vary widely among members of this order.

Woodpeckers and their related species are found in most parts of the world, with the exception of, as well as, Madagascar and.

Detachment Cranes (Cranes, coots, shepherds, etc.)

Japanese crane

Detachment crane-like ( Gruiformes) includes about 200 living species. Members of the order vary widely in size and appearance, but are usually characterized by their short tails, long necks, and rounded wings.

Cranes with long legs and necks are the largest members detachment; the Indian crane with a height of more than 1.7 m has a wingspan of up to 2.5 m.

Furaliformes also include birds that do not match other orders in their characteristics. Currently, the detachment has 9 living families.

The goat-like squad

In the detachment of goat-like ( Caprimulgiformes) there are about 100 species of birds distributed throughout the world, with the exception of Antarctica. Their patterned feathers are often quite variegated, so they fit well into their preferred feathers (these birds tend to nest either on the ground or in trees).

In the modern classification, the goat-like detachment has 5 families:

• Guajaro ( Steatornithidae);
• Frogs ( Podargidae);
• Giant Nightjars ( Nyctibiidae);
• Owl nightjars ( Aegothelidae);
• Real nightjars ( Caprimulgidae).

Order Cuckoo-like (Cuckoo)

Common cuckoo

Detachment cuckoo-like ( Cuculiformes) includes the only cuckoo family, which has about 140 species.

Cuckoos are medium-sized, thin-skinned birds that live in savannas and feed mainly on insects and insect larvae. Some species of cuckoo are known to pop their eggs into other people's nests, and when a cuckoo chick hatches, it sometimes pushes other chicks out of the nest!

Order Chicken-like (Guinea fowl, pheasants, partridges and craxes)

Common pheasant

Some representatives of chickens ( Galliformes) are well known to people who love to eat poultry, including pheasants, quails, turkeys, guinea fowls, and others. In total, this order has 5 families and about 250 species. Many of the less familiar birds are subject to intense hunting pressure and are on the verge of extinction today. Other members of the order, such as chickens, quails, and turkeys, have been fully domesticated and are often raised on farms around the world in huge numbers.

The smallest species of chickens is the painted quail, which has a body length of less than 15 cm; the largest species of the order is the North American wild turkey, which can reach a length of over 1 m and a weight of about 8 kg.

Detachment Pelicans (Pelicans, herons and ibises)

To the detachment pelican-like ( Pelecaniformes) include the families: pelican, heron, whale-headed, hammer-headed and ibis. These birds are characterized by webbed feet and their various anatomical adaptations for catching fish, their main food source; many species are excellent divers and swimmers.

Pelicans are the most famous representatives of the order, they have special leather bags in the lower part of the beak, which allow the birds to effectively catch and hold fish. There are eight types of pelicans in total.

Squad Penguin (Pigwins)

Squad penguin ( Sphenisciformes) includes six genera and about 20 species of penguins. The most diverse are the crested penguins, a genus that includes 6 species.

Parrots are monogamous, forming strong pairs. Most parrots feed almost exclusively on fruits, seeds, nuts, flowers, and nectar, but some species may eat (such as invertebrate larvae) or small animals (such as snails).

Mouse Bird Squad

Bird squad Coliiformes includes six live species of mouse birds that deftly climb trees in search of fruits, berries and random insects. These birds are confined to the open forests, shrubs and savannas of sub-Saharan Africa. They usually gather in flocks of up to thirty individuals, with the exception of the breeding season.

One interesting fact about mouse birds is that they were much more numerous during the later time than they are today; in fact, some naturalists refer to these virtually unknown birds as "living fossils."

Order Raksha-like (Kingfishers, bee-eaters, rakshas, \u200b\u200betc.)

Shellfish ( Coraciiformes) - this is a detachment of mainly carnivorous birds, which includes kingfishers, bee-eaters, earthen rakshas, \u200b\u200brollers, broad-mouthed, etc. Some members of this detachment are solitary, while others form large groups. Many species are brightly colored, and all have legs with three toes pointing forward and one backward. Coraciiformes they like to nest in tree holes or dig tunnels in the mud, along river banks.

According to the modern classification, the Raksheiformes order is subdivided into 6 families:

• Kingfisher ( Alcedinidae);
• Earth raksha ( Brachypteraciidae);
• Roller-shaped or true raksha ( Coraciidae);
• Shchurkov ( Meropidae);
• Momotov ( Momotidae);
• Todiev ( Todidae).

Squad Charadriiformes

Order Charadriiformes ( Charadriiformes) has about 350 species of birds living along the coastlines. Charadriiformes are experienced pilots; some species make the longest and most exciting migrations in the bird class.

Charadriiformes eat a wide variety of foods, including sea worms, crustaceans and earthworms, but surprisingly, they almost never eat fish!

Detachment Grouse (Hoofs and Sandgrouses)

Representatives of the detachment are grouse ( Pteroclidiformes) are medium-sized birds native to Africa, Madagascar, the Middle East, Central Asia, India and the Iberian Peninsula. There are 16 species of Sandgrouse, which belong to two genera.

The grouse are characterized by their small heads, short necks, short, feather-covered legs, and ragged bodies; their tails and wings are long and sharp, well suited to take off quickly to escape predators.

Order Owls (Owls, owls, eagle owls, barn owls, etc.)

Squad owls ( Strigiformes) consists of over 200 species, medium to large birds, equipped with strong claws, good hearing, and keen eyesight. Because they hunt at night, owls have especially large eyes (they help them see in the dark), as well as binocular vision, which helps them see their prey better.

They are opportunistic carnivores that feed on everything from small mammals, reptiles and insects to other birds. Having no teeth, they swallow their prey whole and, after about six hours, regurgitate the indigestible parts of the eaten prey.

Owls live on all continents except Antarctica. They are found in a wide variety of terrestrial habitats, ranging from dense forests to wide open grasslands.

Squad Falconiformes (Birds of Prey)

Black vulture

Falconiformes ( Falconiformes), or birds of prey, include eagles, hawks, kites, secretary birds, osprey, falcons, vultures, and vultures, about 300 species in total. Representatives of the squad are formidable predators, with powerful claws, curled beaks, keen eyesight and wide wings, well suited for flight and diving. Falconiformes hunt during the day, feeding on fish, small mammals, reptiles, other birds and abandoned carrion.

The largest bird of prey is the Andean condor, whose wingspan is close to 3 m.One of the smallest birds of prey is the steppe kestrel, with a wingspan of less than 75 cm.

Order Swift (Hummingbirds and Swifts)

A detachment of swift, or long-winged ( Apodiformes) is the most numerous in the class of birds after passerines, it has about 450 species of swifts and hummingbirds. In the classification of Sibley - Alqvist, this detachment rises to the superorder Apodimorphae, in which hummingbirds are separated into a separate order Trochiliformes.

The birds are characterized by their small size, short legs and tiny feet. Hummingbirds and swifts, included in this group, also have numerous adaptations for specialized flight.

Hummingbirds are found in different regions of North, Central and South America, and swifts can be found on all continents of the world, with the exception of Antarctica. Earliest known members Apodiformes were fast birds that evolved in the early Eocene era in northern Europe about 55 million years ago; hummingbirds appeared a little later, they separated from the early swifts after the late Eocene.

Trogon-like squad (Trogon and quetzal)

Trogon-like ( Trogoniformes) there are about 40 species of trogons and quesals, tropical forest birds found in the Americas, southern Asia, and sub-Saharan Africa. These birds are characterized by short beaks, rounded wings and long tails, and many are brightly colored. They feed mainly on insects and fruits, and also build their nests in trees or abandoned insect burrows.

Mysterious, like their vaguely alien names, trogans and quezals turned out to be difficult to classify: in the past, scientists united these birds with all orders, from owls and parrots to tinamous. Recently, however, molecular data indicate that trogons are closely related to the rakshid, with which they may have separated 50 million years ago. These birds are rarely found in the wild and are considered especially valuable finds by bird watchers.

Squad Turakiformes (Turaco and bananoed)

Turakiformes ( Musophagidae) - a detachment of birds that previously belonged to the cuckoo. A recent genetic analysis has confirmed that this is a separate order.

Musophagidaeare medium-sized birds that are endemic to sub-Saharan Africa, where they live in forests and savannah. They fly poorly, but move quickly through trees. They feed mainly on fruits and to a lesser extent on leaves, buds and flowers, occasionally eating small insects, snails, and slugs.

These are gregarious birds that do not migrate, but gather in family groups of up to 10 individuals. Many species can emit high-pitched alarms that alert other animals to the presence of predators or humans.

Squad Flamingos (Flamingos)

Flamingos ( Phoenicopteriformes) is an ancient order of birds, consisting of six species of the genus flamingos. These birds use their special beaks to extract tiny plants and animals from the water. Flamingos are very social birds, forming large colonies of several thousand individuals. They synchronize mating and egg laying during the dry season, and when the water level drops, flamingos build their nests on the exposed mud. Their preferred habitats include lagoons, mangrove swamps, large alkaline or salt lakes, etc.

General characteristics. Birds - warm-blooded vertebrates from the group Amniota, adapted for flight. The forelimbs are modified into wings. The body is covered with feathers, which also form the supporting plane of the wings and tail. Part of the bones of the metatarsus and tarsus, merged, formed a single bone - the tarsus. The skull is articulated with the spine by one condyle. The cerebral hemispheres have a cortex, but their surface is smooth. The cerebellum is well developed. Lungs are spongy, connected to a system of air sacs. The heart is four-chambered. There is only the right aortic arch, the left one atrophies even during embryonic development. The excretory organs are the pelvic kidneys. Fertilization is internal. They reproduce by laying eggs.

Currently, the Earth is home to about 9 thousand species of birds that inhabit all continents and islands. There are about 750 bird species in the USSR.

Modern birds are subdivided into three distinct supra-orders: (Carlnatae) , Keelless birds (Ra- titae), Penguins { linpennes).

Structure and vital functions. The appearance of birds reflects their fitness for flight (Fig. 247). The body is streamlined, egg-shaped, compact. The neck of most birds is thin and flexible. On the head, a beak protrudes forward, consisting of a beak and a lower beak. The modified forelimbs - wings serve for flight. Most of their bearing plane is formed by large elastic flight feathers. The legs of the birds take all the weight of the body, when moving on the ground, climbing trees, taking off and landing. The legs have four sections: thigh, lower leg, tarsus and toes. Usually the bird's legs are four-toed, but sometimes their number is reduced to three or even two (African ostrich). Of the four fingers, in most cases, three are directed forward and one is directed backward.

Figure: 247. Outer (Field Harrier)

Veils. The skin of birds is thin, dry. The skin glands are absent. Only above the base of the tail in most birds is a special coccygeal gland, the secret of which is used to lubricate the feathers, which prevents them from getting wet. For birds, feather cover is characteristic. Feathers are common to all types of birds and are not found in other animals. Bird feathers evolved from the horny scales of reptiles.

The feather is a derivative of the skin epidermis (Fig. 248). It is formed by the horny substance - keratin. A separate feather consists of a quill (a part immersed in the skin), a shaft and a fan.

Figure: 248. The structure of poultry nerms:

/ - rod; 2 - outer fan; 3 inner fan; ■ / - trunk; 5 - ochip; 6 "- full hole; 7 bow

Figure: 249. The structure of the bird's wing:

/ - brachial bone; 2 - elbow bone; 3 ...... the radius;

4 - the bone is po-zapyasgpan; 5 ......... part of the wrist; 6 ", 7

phalanges of the fingers; 8 - winglet; {.) pterygoid membrane; 10 - the bases of the flight feathers; // - primary flight feathers; 12 - secondary flight feathers

The rod is a dense corneal tube with a loose corneous core. The fan is formed by first-order barbs extending from the rod in both directions, from which, in turn, short second-order barbs extend. The beards of the second order bear small hooks that connect the beards to each other, which is why an elastic light blade of the feather fan is formed. In delicate downy feathers, the shaft is shortened and bears thin delicate beards not interlocked by hooks. In fluff, the shaft is not developed and the barbs extend in a bundle from the common base.

Large elastic feathers that form the main part of the wing bearing plane are called flight feathers. Their fan is asymmetrical - the front side is narrow and the back side is wide. Such a structure allows the passage of air between the feathers when the wing is raised, and when the wing is lowered under air pressure, it causes a tight connection of the feathers. Larger flight feathers, resting on the bones of the wing hand, are called primary flight feathers, and smaller and less elastic feathers, connected to the bones of the forearm, "are secondary flight feathers (Fig. 249). Tail feathers that make up the tail and direct the flight of birds, They are distinguished by their large size, elasticity and asymmetry of the webs.The smaller feathers covering the body of birds are called contour, they give the body a streamlined shape.The areas on which they are located are called pterilias, and the areas of the skin without them are called apterias (Fig. 250). Apterias are located along the midline of the chest, in the axillary region, along the shoulder blades, that is, in those places of the body where the skin over the muscles is strained during flight. Apterias are covered with adjacent contour feathers. down feathers and down are located, warming the body.

The role of feather cover in the life of birds is great and varied. The flight and tail feathers form the majority of the wing and tail bearing surface and are therefore essential for flight. The feather cover gives the birds a streamlined shape, which facilitates their flight. Due to the high heat-shielding properties of feathers and air layers between them, the feather cover helps to preserve body heat in birds and, therefore, participates in thermoregulation of the body. It also protects the bird from various mechanical influences. A variety of feather pigments give birds a particular color, which is often patronizing.

Periodically, usually once or twice a year, the feather cover of birds is completely or partially renewed by molting; at the same time, old feathers fall out, and new ones develop in their place (sometimes of a different color). In most birds, plumage molt proceeds slowly and gradually, due to which they retain the ability to fly, but in waterfowl it proceeds so quickly that they temporarily cannot fly.

Figure: 250. Pterszhy and aptria birds (pigeon)

Figure: 251. The skeleton of a bird (dove):

/ - cervical vertebrae; 2 - thoracic vertebrae; 3 - tail vertebrae; 4
- coccygeal bone; 5, in-edges; 7 - sternum; S - keel; .V - scapula; 10 - coracoid; // - clavicle (fork); 12
-- brachial bone; 13 - radius bone; 14- elbow bone; 15 -

metacarpus; 16 .....18 - phalanges of the fingers;

19 -21- pelvic bones; 22 - thigh bone; 23 - shin bone; 24 - tarsus; 25, 26 - phalanges of the fingers

The skeleton of birds is light and at the same time strong, which is important for flight (Fig. 251). Its lightness is achieved by the thinness of its constituent bones and the presence of cavities in the tubular bones of the forelimbs. The strength of the skeleton is largely due to the fusion of many bones.

The bird's skull is distinguished by a large thin-walled cerebral box, huge eye sockets, and toothless jaws. In adult birds, the bones of the skull are completely fused, which ensures its strength. The skull articulates with the first cervical vertebra by one condyle.

The cervical vertebrae, the number of which varies in different birds, are articulated with each other by saddle-shaped articular surfaces, which gives the neck more flexibility. The thoracic vertebrae in adult birds are spliced \u200b\u200btogether. The ribs are attached with the lower ends to the sternum; at the posterior edge, they have hook-shaped processes, which overlap the ends of the ribs of the next pair; this gives the chest strength. The sternum of birds, with the exception of those that have lost the ability to fly, carries a high bone keel on the front surface, to which powerful pectoral and subclavian muscles are attached on both sides, which set the wing in motion.

The posterior thoracic, lumbar, sacral and - anterior caudal vertebrae in adult birds grow together with each other and with the thin iliac bones of the pelvis into a single sacrum, which serves as a solid base for the legs. The posterior caudal vertebrae merge to form the coccygeal bone, which looks like a vertical plate. It serves as a support for the tail feathers.

The shoulder girdle consists of three pairs of bones: saber-shaped shoulder blades, lying along the spine; swampy clavicles, which grow together with the lower ends into a fork, expanding the bases of the wings; coracoids - massive bones connected at one end with the shoulder blades and bases of the humerus, and the other with the sternum.

The skeleton of the wing consists of a large, hollow inside the bone of the shoulder, two bones (ulna and radius) of the forearm, a number of fused bones of the wrist and metacarpus and highly reduced and altered phalanges of II, III and IV fingers, I and V fingers are atrophied, II has only one phalanx , which serves as a support for a separate tuft of feathers on the outer edge of the wing, the so-called winglet.

The pelvic girdle of the skeleton is formed by thin iliac, pubic and ischial bones that grow together in adult birds into a single bone. The posterior ends of the pubic and ischial bones in most birds (except for some ostriches) do not converge, so the pelvis remains open from below.

The skeleton of each of the hind limbs consists of a large thigh bone, two bones of the lower leg (tibia and tibia), tarsus and phalanges of the fingers. The fibula is highly reduced and accreted to the tibia. In the process of ontogenesis, the bones of the main row of the tarsus grow to the lower end of the tibia. The remaining bones of the tarsus and three bones of the metatarsus merge into a single elongated bone - the tarsus. The phalanges of the fingers are attached to the lower end of the tarsus.

Musculature. The pectoral and subclavian muscles, which set the wings in motion, are especially developed. The muscles of the legs are also powerful, doing a lot of work when walking a bird and moving along tree branches, during takeoff and landing.

The nervous system, especially the central part, in birds has a more complex structure than in reptiles, which corresponds to a higher level of vital activity. The bird's brain is distinguished by the large size of the forebrain hemispheres, the strong development of the optic hillocks of the midbrain and a huge corrugated cerebellum (Fig. 252). The roof of the hemispheres has a smooth surface, and the gray medulla in it is weakly expressed. The strong development of the visual tubercles of the midbrain, which carry the visual function, is due to the importance of vision in the life of birds. The cerebellum is large and complex in structure. Its middle part - a worm - almost touches the hemispheres with its front edge, and covers the medulla oblongata with its posterior end. The worm is covered with characteristic transverse grooves. The development of the cerebellum is associated with flight, which requires precisely coordinated movements. There are 12 pairs of cephalic nerves in birds.

Digestive organs begin with the oral cavity. Teeth in modern birds are absent - they are partially replaced by the sharp edges of the horny cover of the beak, with which the bird captures, holds and sometimes grinds food (Fig. 253). The long esophagus in many birds expands into a crop; here the beggar, being treated with saliva, swells and softens. From the esophagus "food enters the glandular stomach, where it mixes with digestive juices. From the glandular stomach, food passes into the muscular stomach. Its walls are folded with powerful muscles, and in the cavity lined with a hard shell, there are usually small stones swallowed by a bird. These stones and folds the walls of the stomach with the contraction of the muscles of the walls grind food.

The intestines of birds are relatively short. It distinguishes between a longer thin and less extended thick sections. At the border of these sections, two blind outgrowths depart from the intestine. The rectum is not developed, so the feces do not accumulate in the intestines, which makes the weight of the bird easier. The intestine ends with an expansion - a cloaca, into which the ureters and ducts of the sex glands open. Secrets of the large two-lobed liver and pancreas, entering the duodenum, facilitate the digestion of food.

The consumption of a huge amount of energy by birds during the flight and a high level of metabolism necessitate the absorption of large masses of food. So, a small bird of our forests, a king, per day consumes an amount of food exceeding "/ 4 body weight. Digestion processes in birds proceed very quickly: in waxwings, rowan berries pass through the entire intestine in 8-10 minutes, and in a duck opened 30 minutes after after she swallowed a 6 cm long crucian carp, it was no longer possible to find its remnants in the intestines.

Figure: 253. Internal structure of a bird (pigeon):

/ - opened pigeon; // - section of the stomach of a pigeon;

/ - trachea; 2 - the esophagus; 3 - goiter; 4 - lung; 5 - air bags;

6 - heart; 7 - glandular stomach; 8 - gizzard

The respiratory organs of birds also bear signs of adaptation to flight, during which the body needs increased gas exchange (Fig. 254). A long trachea departs from the bird's throat, which is divided into two bronchi in the chest cavity. At the site of the division of the trachea into bronchi, there is an extension - the lower larynx, in which the vocal cords are located; its walls have bony rings. The lower larynx plays the role of a vocal apparatus and is especially strongly developed in birds that sing or make loud sounds.

The lungs of birds have a spongy structure. The bronchi, entering the lungs, disintegrate into smaller and smaller branches. The latter end in the thinnest blind tubules - bronchioles, in the walls of which the capillaries of blood vessels pass.

Part of the branching of the bronchi extends beyond the lungs, continuing into thin-walled air sacs located between the muscles, among the internal organs and in the cavities of the tubular bones of the wings. These bags play a large role in the breathing of the bird during flight. In a sitting bird, breathing is carried out by expanding and contracting the chest. In flight, when the moving wings need solid support, the chest remains almost motionless and the passage of air through the lungs is mainly due to the expansion and contraction of the air sacs. This process is called double breathing, since oxygen is released into the blood both during inhalation and exhalation. The faster the flapping flight, the more intense the breathing. When the wings are lifted, they stretch and air is sucked into the lungs and further into the bags. When the wings are lowered, exhalation occurs, and air passes through the lungs siltbags, which promotes the oxidation of blood in the lungs.

/ trachea;
2-- lungs; 3-11
- air bags

Figure: 255. The circulatory system of a bird (pigeon):

/ spicy atrium; 2 - right ventricle of the heart; 3 - left pulmonary artery; 4 right pulmonary artery; 5 - left atrium; 6 - the left ventricle of the heart; 7 - the right aortic arch; H, 9 -unnamed arteries; 10 -12 - carotid arteries; 13 - subclavian artery; 14-- left thoracic artery; 15 - aorta; 16 - the right femoral artery; 17 renal artery; 18 -the sciatic artery; 19 -- iodine artery; 20 posterior mesenteric artery;
21 - tail artery; 22 tail vein; 23 - portal vein of the kidney; 24 - femoral vein; 25 - iodine-I! tire yen; 2 inposterior vena cava; 27 - intestinal vein; 28
- supra-intestinal vein; 29 renal vein; 30 - jugular vein; 31
- subclavian vein; 32 - anterior vena cava

The circulatory system of birds has two circles of blood circulation (Fig. 255). A large heart is completely divided into right and left halves and has left and right atria and left and right ventricles. This achieved a complete separation of arterial and venous blood flows. Arterial blood, coming from the lungs to the pulmonary vein, enters the left atrium, and from there into the left ventricle, from which it goes into the aorta. Venous blood from all over the body enters the right atrium, and from it into the right ventricle, in order to then go through the pulmonary artery to the lungs.

In embryos of birds, as well as reptiles, both the left and right aortic arches are laid, but in the process of embryonic development of the animal, the left atrophies. Starting from the left ventricle of the heart, the right aortic arch bends to the right (which is why it is called right), turns back and continues with the trunk of the aorta, stretching under the spine. Large paired unnamed arteries branch off from the aortic arch, which soon divide into the carotid arteries that carry blood to the head, and powerful thoracic and subclavian arteries that go to the pectoral muscles and wings. From the dorsal aorta, arteries branch off to various parts of the bird's trunk and legs. The venous system of birds is basically similar to that of reptiles.

The high activity of the metabolic process in birds makes it necessary to quickly and abundantly deliver nutrients and oxygen to all parts of the body. Therefore, their blood circulation occurs very quickly, which is ensured by the energetic work of the heart. So, in many small birds, the heart beats more than 1,000 times per minute (in humans, 60-80 times).

The excretory organs of birds are also adapted to the intensive metabolism in the body, as a result of which the volume of decay products to be removed increases. The kidneys in birds are large and lie in the depressions of the pelvic bones. From them, the ureters depart, opening into the cloaca. Thick urine enters the cloaca, from where it is excreted along with feces.

Reproductive organs. The two testicles lying in the abdominal cavity are bean-shaped. The vas deferens depart from them, opening into the cloaca. In some birds (geese), males have a copulatory organ. Females usually have only one, left, ovary, which lies near the kidney. The egg released from the ovary enters the unpaired oviduct, in the upper part of which fertilization takes place. After passing through the oviduct, the egg acquires a protein shell, and once in a wider uterus, it becomes covered with a calcareous shell. Through the final section of the female's reproductive tract - the vagina - the egg enters the cloaca, and from there it is taken out.

Figure: 256. The structure of a bird's egg:

/ ...... shell; 2 -..... nodoshell shell; ,4 -

air chamber; * "/ protein; L vitelline membrane; inyolk; 7 - embryonic disc;
H ~white yolk; 9 -yellow yolk; 10 --chalazi

The bird's egg is very large (relative to the size of the animal), since it contains many nutrients in the form of yolk and protein (Fig. 256). The embryo develops from a small embryonic disc located on the surface of the yolk.

At the blunt end of the egg, the shell and shell membrane contains a cavity filled with air; it helps the fetus to breathe. The development of a chick in an egg is shown in Fig. 257.

Figure: 257. Development of a bird embryo:

/- IV - successive stages of development of cmbryo; / - embryo; 2 - yolk; 3 -protein; 4-- amshutic fold; 5 cervical cavity; 6 "- air chamber; 7 - ~ shell; H-
serosa; 10 - amnion cavity; // - allantois; 12 ■- yolk sac

Bird ecology. The main form of movement of most birds is flight. Adaptation to flight caused a number of the described changes in the structure of the organism of these animals, and also left an imprint on all types of their vital activity. Due to the ability to fly, birds have enormous opportunities for distant migrations and dispersal: it was flight that allowed them to populate all oceanic islands, often lying hundreds of kilometers from the mainland. Flying helps birds avoid enemies. Many birds get food or look out for food on the ground during flight.

The flight patterns of different bird species are far from the same - it is always in accordance with their lifestyle. There are two main types of bird flight: soaring and rowing. Soaring is the flight of birds on more or less motionless, outstretched wings. This flight can be carried out with a gradual descent of the bird in the air. But often, by hovering, a bird can maintain its gained height above the ground or even rise up (achieved through the use of ascending air currents by the bird). Rowing flight is carried out by flapping the wings. In many birds, this active form of flight alternates with soaring in the air. During a calm rowing flight, a crow makes an average of 2.9, and a seagull makes 2.2 wings per second. The maximum possible flight speed of a swallow is 28 m, a wood grouse is 16 and a swan is 14 m per second. Some birds can fly more than 3 thousand km without stopping for rest.

The ability for active flight, warm-bloodedness and a high level of development of the central nervous system provided birds with the possibility of wide distribution on Earth. With the adaptation of birds in the course of evolution to life in various conditions (forests, open spaces, reservoirs), the formation of different ecological groups is associated, which differ in appearance and specific structural features.

Tree birds - inhabitants of various forests and shrubs. This group includes woodpeckers, parrots, nuthatches, pikas, cuckoos, starlings, blackbirds, pigeons, wood grouses, hazel grouses, etc. They forage and usually nest in trees, less often on the ground. The most specialized birds adapted to tree climbing (parrots, woodpeckers, nuthatches) have strong legs armed with curved claws. Woodpeckers have two fingers directed forward, two - backward, which allows them to deftly climb tree trunks, while leaning on the rigid and elastic tail feathers. When moving along tree branches, parrots use not only their hind limbs, but also their beak.

Land birds - inhabitants of open spaces - meadows, steppes and deserts. This group includes ostriches, bustards, little bustards, some waders. They feed and nest on the ground. In search of food, they move mainly by walking and running, rather than flying. These are large and medium-sized birds with a massive and wide body and a long neck. The legs are long and strong, with short and thick toes, the number of which can be reduced to three, and in the African ostrich, to two.

Wading birds inhabited by swampy meadows, swamps, thickets of coastal reservoirs. Typical representatives: herons, storks, cranes, many waders. The feed is usually collected on the ground. Nests are made on the ground or in trees. These are large or medium sized birds. Most have long, thin legs with elongated toes, with the help of which they easily move on sticky ground or shallow water. The head is small, with a long, hard beak. The wings are well developed. The tail is short. The plumage is loose, with poorly developed down.

Waterfowl a significant part of their life is spent on reservoirs. This group includes loons, grebes, guillemots, guillemots, penguins, cormorants, pelicans, ducks, geese, and swans. They swim well, and many dive, but they walk on land and usually fly badly, and some do not fly at all (penguins). Many birds forage (fish, molluscs, crustaceans) in water, others feed on land with vegetative parts of plants and seeds. They nest along the banks of water bodies, on the ground, in trees, in reed beds, on rocks and in their crevices, in burrows. These are large and medium-sized birds with a body somewhat flattened from the ventral side and a short tail. The legs are set far back, which provides an almost vertical position of the body when walking. They have dense plumage with well-developed down, swimming membranes on their paws, and most have a developed coccygeal gland.

Air-water birds in contrast to the previous group, they are less associated with water bodies. The group includes gulls, terns, petrels. They usually fly well, swim well, but dive poorly. Soaring flight using air swirls over waves or different air speed. They feed mainly on fish, which they look out for during the flight, then quickly rush at it and pull it out of the water with their strong and long beak, bent at the end. They often nest on the banks of rivers, lakes, seas, on rocky ledges of sea shores. These are large and medium-sized birds with an elongated body, long, sharp wings and short legs, on which the three front toes are connected by a swimming membrane. The plumage is dense, with a lot of down.

Airborne birds a significant part of the daylight hours is spent in the air, where they catch insects with their short, wide-opening beak. Typical representatives: swifts, swallows, nightjars. They are excellent flyers with fast and maneuverable flight. They usually nest in buildings, in burrows but on river banks, on the ground. Their body is elongated, the neck is short, the wings are long and narrow. The legs are short, making it difficult to walk on the ground.

Bird feeding. Most birds are carnivorous, others are herbivorous or omnivorous. There are species that feed mainly on vegetative parts of plants (geese), berries (blackbirds, waxwings), seeds (sparrows, crossbills), nectar (hummingbirds), insects (cuckoos, woodpeckers, many passerines), fish (gulls, cormorants, pelicans), frogs (ducks, storks, herons), lizards and snakes (storks, some diurnal predators), birds (hawks), rodents (owls, many diurnal predators). Some predators prefer to eat carrion (vultures, vultures, vultures). The nature of food can vary depending on age: most granivorous birds feed their chicks with insects. The composition of poverty varies according to the seasons of the year. For example, the black grouse in the summer feeds on green parts of plants, berries and insects, and in the winter - mainly on pine needles, buds, shoots and catkins of birch and alder.

Annual periodicity in the life of birds. In birds, like in other animals, the annual frequency of life is closely related to seasonal changes in the conditions of existence and is of great adaptive value. It allows you to time the most crucial moment in the life of each species - reproduction - to a certain season when conditions for feeding chicks will be most favorable. The following stages of the annual cycle of birds can be distinguished: preparation for breeding, reproduction, molting, preparation for winter, wintering.

Preparing for breedingexpressed in the formation of pairs. Association at mating time into bunks (monogamy) is characteristic of most bird species. However, the duration of the existence of pairs in different birds is significantly different. Swans, storks, eagles form pairs for several years or perhaps even for life. Other birds mate during the breeding season, and many ducks only mate until lay. In a smaller number of bird species, pairs are not formed and the male fertilizes several females during the breeding period, which bear all the care of the offspring. This phenomenon has received the name and about ln-gamia (polygamy). It is characteristic of black grouse, pheasants, wood grouse, domestic chickens. Sexual dimorphism is especially pronounced in these birds.

Breeding into pairs in birds is accompanied by mowing: birds take various poses, keep their plumage unusually, emit special sounds, and in some polygamous species there are fights between males. The mating behavior of birds facilitates the meeting of individuals of different sexes and the formation of pairs, stimulates the synchronous maturation of the reproductive products of both partners.

The fertility of birds is much less than that of reptiles, which is associated with the presence of various forms of care for the offspring in birds (nesting, incubation and feeding of chicks). The number of eggs in a clutch ranges from 1 (penguins, guillemots) to 22 (gray partridge). Most birds incubate their clutch. In polygamous species, incubation is carried out only by the female (chickens, anseriformes), in monogamous species - alternately by a male and a female (pigeons, gulls, many passerines) or only by a female, and the male feeds her and protects the nesting area (owls, diurnal predators, some passerines).

The duration of incubation in different birds is different and depends on the size of the egg and bird, the type of nest and the intensity of incubation. Small passerines incubate for 11-12 days, crow - 17, swans - 35-40. Duration of incubation in poultry: chicken 21 - days, duck - 28, goose - 30, turkey - 28, 29 days.

Depending on the degree of development of the chicks that have just hatched from the eggs, birds are divided into brood, semi-brood and chicks (Fig. 258). The chicks of brood birds are pubescent, sighted, capable of feeding on their own after a short time (chickens, anseriformes, ostriches). Chicks of semi-brood birds hatch sighted and pubescent, but are fed by their parents until they acquire the ability to fly (gulls, guillemots, petrels). In chick birds, chicks are naked, blind, and remain in the nest for a long time (passerines, woodpeckers, pigeons), where their parents feed them intensively. So, a pair of flycatchers, tits or warblers brings food to their chicks up to 450-500 times a day.

After the end of feeding the chicks, the family usually breaks up and the birds unite in flocks. The highest mortality is observed in the first year of bird life. Sometimes it can reach more than 50 % the number of individuals flew out of the nest. Birds reach sexual maturity at different ages. Most small and medium-sized birds (many passerines) begin to breed as early as the next year of life, larger birds (hooded crow, ducks, small carnivores and gulls) - by the 2nd year, and loons, eagles, petrels - by 3-4 -m, ostriches - at the 4th - 5th year.

Figure: 258. Chicks of different birds at the same age:

/ - chicks (skate); // - semi-brood (eagle); /// - brood (partridge)

The average lifespan of small passerine birds is 1 - 1.5 years, and the maximum life span is 8-10 years. Larger bird species can live for 40 years or more.

Molting proceeds differently in different birds. In some species (passerines) it is gradual, in others (chickens, anseriformes) it is stormy. Linear anseriformes lose their ability to fly for 2-5 weeks. Molting usually begins immediately after breeding. In males of many bird species that do not participate in breeding, molt occurs earlier than in females. Shedding males of wood grouses and black grouses keep one by one in remote areas of the forest, and duck drakes accumulate in large numbers during the molt period in hard-to-reach wetlands.

Preparing for winter . During this period, birds begin to wander in search of food. Intense nutrition ensures fat accumulation. Some birds tend to store food, which makes their wintering easier. Jays are collected and buried in the soil or under the forest floor of acorns, and nutcrackers are nuts. In winter, birds use these reserves only partially. Another part of the seeds is eaten by murine rodents and insects or, remaining until spring, germinates. Nuthatches and tits hide the seeds of various trees in cracks in the bark, providing themselves with 50-60% fodder. Small owls (passerine and uplifted owls) harvest the carcasses of mouse-like rodents for the winter and put them in the hollows of trees. Birds find their pantries, apparently, thanks to memory and sense of smell.

Wintering a.In winter, birds face great difficulties in obtaining the right amount of feed. In search of habitats that can most fully provide this or that species with food and protective conditions, many birds begin to make directional movements (migrations and migrations). Only sedentary birds remain in the places where their breeding took place, and if they change their habitats, they fly away no further than several tens of kilometers (wood grouses, hazel grouses, woodpeckers, sparrows, tits). Birds can fly away hundreds of kilometers, but they usually stay within the same natural zone (waxwings, tap dancers, bullfinches). The farthest migrations are made by migratory birds, wintering in other natural zones located thousands of kilometers from their nesting sites.

The division of birds into sedentary, nomadic, and migratory birds is complicated by the fact that the same species in different parts of its range can behave differently. So, the hooded crow in the south of the European part of the USSR is a sedentary species, in the south it is migratory. Changes in weather and feeding conditions over the years also affect the nature of the mobility of birds. In warm winters, with sufficient food supply, some species migrating for a given area remain to winter in their breeding places (ducks, rooks, blackbirds). This indicates that the main reason for bird migration is seasonal changes in living conditions. In areas where these changes are more pronounced in seasons, the number of migratory species is greater. So, in the USSR, out of 750 bird species, 600 are migratory, wintering mainly in the British Isles, southern Europe, the Mediterranean, Africa and Asia.

The migratory routes of birds are enormous. The flight path of our warblers and swallows wintering in Africa is 9-K) thousand km, and the polar tern from the coasts of the Barents Sea to the coasts of Africa is 16-18 thousand km. The flyways of waterfowl and wading birds are confined to river valleys and sea coasts, where there are conditions suitable for their rest and feeding. Many birds fly in a wide front. Small passerines cover a distance of 50 ..... 100 km per day, ducks - 100-

500, storks - ~ 250, woodcocks 500 km. Birds usually spend 1-2 hours per day for flight, using the rest of the time for stops for rest and feeding. Crossing bodies of water, they fly thousands of kilometers without rest. In spring, bird stops are more rare and short-lived than in autumn; therefore, spring migrations usually occur at a faster rate than autumn ones.

Bird migration is one of the most interesting and poorly studied questions of bird biology. Until now, the mechanism that determines the orientation of birds during migration has not been fully understood. On the basis of observations in nature and the setting of experiments, it was possible to reveal that migrating birds can orient themselves in the position of the sun, moon, stars, and in the features of the landscape. The innate migratory instinct plays an important role in the migratory behavior of birds and the choice of a general direction during flight. However, it manifests itself in the presence of a certain amount of environmental factors. Under the influence of environmental conditions, it is possible to change this innate instinct.

Bird migration has developed over millennia. The influence of the Ice Age on the formation of bird migration routes in the Northern Hemisphere is undeniable. The modern flyways of some birds repeat the historical path of their dispersal in the postglacial period.

The method of ringing is of great importance for the study of bird migration, when chicks, before flying out of the nest or adult birds, are put on a metal ring on their paws with the number and designation of the institution conducting the tagging. In our country, all information about ringing and the extraction of ringed birds is sent to the Banding Center of the USSR Academy of Sciences (Moscow). About 1 million birds annually ring around the world, of which more than 100 thousand in the USSR. Ringing allows you to trace migration routes, flight speed, life expectancy and other important issues of bird ecology.

The economic value of birds. The role of birds in human economic activity is great and diverse. Birds domesticated by man (chickens, geese, ducks, turkeys, guinea fowls, pigeons) have long been used to obtain meat, eggs, down, feathers and other valuable products and industrial raw materials from them. In our country, poultry farming is the most important and rapidly developing branch of animal husbandry. Many species of wild birds (chickens, anseriformes, some waders) serve as objects of sports and commercial hunting, which makes it possible to additionally involve a significant amount of tasty meat in the economic circulation.

The role of birds in the extermination of insects and murine rodents - agricultural pests is great. The importance of tits, flycatchers, nuthatches, starlings, thrushes and many other birds as regulators of the number of harmful insects especially increases during the period of feeding the chicks. Thus, the family of the common starling during the nesting period destroys 8-10 thousand May beetles and their larvae, or over 15 thousand caterpillars of the winter moth. Many birds of prey, owls, gulls, storks and a number of others exterminate mice, voles, ground squirrels, rats, hamsters and other harmful rodents. The usefulness of birds is associated with their ability to quickly find and concentrate in the centers of mass reproduction of pests, and for many species of birds - to switch to numerous, although often not typical for them, food. So, in the years of mass breeding of murine rodents, rooks, gulls, etc. begin to feed on them.

Some birds act as plant distributors. For example, in the taiga of Eastern Siberia, the restoration of cedar is often associated with the activity of nutcracker. Jays are involved in the settlement of oak. Waxwing, blackbirds, hazel grouses and many others carry the seeds of mountain ash, bird cherry, blackthorn, elderberry, viburnum, euonymus, blueberry, raspberry, lingonberry, etc.

Figure: 259. Various types of crowbars for hezdonapiya beneficial insectivorous BIRDS

To increase the number and attract useful birds, they create favorable conditions for their nesting, hang artificial nesting places: birdhouses, nest boxes (Fig. 259),

carry out winter feeding it.e. When artificial nesting sites are hung, the number of duylogynpkov (flycatchers, titmice, starlings) sharply increases.

In some cases, birds can cause some damage. Rooks, useful in killing soil insects, in places harm crops (especially corn) by pecking seeds and pulling out seedlings. Wandering starlings peck at ripe cherries and grapes. In the southern regions of our country, in some places, sparrows cause serious damage to the grain harvest. Bee-eater, which exterminates bees, can be harmful to beekeeping. Reed Harrier and Hooded Crow are sometimes harmful to the hunting economy. In a collision with high-speed aircraft in the air, birds sometimes cause serious accidents, which leads to the creation of a system for scaring birds away from the territory of airfields. It is also necessary to take into account the role of birds in the spread of some diseases dangerous for humans and farm animals (psittacosis, influenza, encephalitis, etc.).