Synopsis: Bird class. Kharchenko N

"Class - Birds"

Birds are highly organized vertebrates. The ability for long-term flight, warm-bloodedness and other features of life gave them the opportunity to spread widely on Earth. The life of birds is associated with meadows, fields, swamps, banks of reservoirs, open areas of water. However, most of their species are forest dwellers. In the crowns of trees and shrubs, tits, kinglets, crossbills are common, on tree trunks - woodpeckers, nuthatches, pikas, on the ground - black grouse, hazel grouse, capercaillie. In terms of the number of species, the class of birds is the largest among terrestrial vertebrates (about 9 thousand species).

Features of the structure and life of birds

The ability to fly, along with other modes of movement, determined many specific features of the external and internal structure of birds.

External building. Birds have a relatively small head, a long movable neck, and a compact body. On the head there is a beak, consisting of bone jaws and horn covers. The nostrils are located on the mandible. Large eyes have movable eyelids and a nictitating membrane. On the head (closer to the back of the head) are the auditory openings.

The body of birds is covered with feathers: contour, down, down. The contour feather consists of a rod, a dense plate - a fan, a free part of the rod - an ochin. The fan is formed by barbs of the first and second order, interlocking with each other by microscopic hooks of barbs of the second order. The downy feather does not have a dense fan. Down - feathers with a very short stem and a bunch of beards extending from it. Contour feathers streamline the body of the bird, protect from the wind. The largest of them form the flying surface of the wings (primary feathers) and tail (tail feathers). Down feathers and down prevent heat transfer. Birds restore the integrity of split webs with their beaks, lubricate them with fat. Worn out feathers are replaced with new ones during the seasonal molts.

The skin of birds is thin and dry. Most have only the coccygeal gland (produces an oily liquid with which birds lubricate feathers). On the legs of birds there are horny scales.

Skeleton features. The skeleton of birds is light (most of the bones are filled with air) and strong (many bones fuse together in the early stages of embryonic development). The cervical region includes from 11 to 25 vertebrae (the head can turn almost 180 degrees). The thoracic vertebrae are fused together. With the ribs and sternum, they form the ribcage. Most birds have an outgrowth on the sternum - a keel. It increases the area of ​​attachment of the pectoral muscles.

The last thoracic vertebra, all the lumbar, sacral and anterior caudal vertebrae are fused into a complex sacrum. The tail section consists of several movably connected vertebrae and vertebrae that form the coccygeal bone, which serves as the site of attachment of the tail feathers.

In the skeleton of the wing, 3 underdeveloped fingers were preserved, the small bones of the hand fused into a single bone - a buckle. The girdle of the forelimbs consists of paired shoulder blades, clavicles (fused at the lower ends) and crow bones. In the skeleton of the legs, several small bones of the foot have grown together into a single bone - the tarsus, which allows the bird to walk. The belt of the hind limbs - the pelvis is formed by two pelvic bones fused with a complex sacrum.

Musculature of birds. Muscles in birds have reached a high development, especially the pectoralis major muscles that lower the wings. In good flyers, they make up 1/5 of the body weight. Among the muscles of the hind limbs (up to 35 individual muscles) there are muscles with long tendons. When a bird sits on a branch, the tendons stretch and squeeze the fingers.

Features of the structure of the organs of the body cavity. The esophagus in many birds has an expansion - goiter, where food accumulates, softens and is partially digested. The stomach consists of two sections: glandular and muscular. In the glandular, food is processed by digestive juices, in the muscular, it is ground with small pebbles swallowed by birds. The large intestine is short and the birds defecate frequently (an adaptation to relieve body weight). Birds have a cloaca.

The lungs of birds are dense spongy bodies. Air passes through the trachea, two bronchi, which branch and end in thin-walled bubbles, braided with capillaries. Part of the branches of the bronchi extend beyond the lungs and form air sacs, the main role of which is to participate in the breathing mechanism during flight. When the wings rise, the volume of the body cavity increases, which leads to stretching of the air sacs. In this case, air from the lungs passes into the anterior air sacs, and air from the external environment through the respiratory tract goes into the lungs and into the posterior air sacs. During this time, gas exchange takes place in the lungs. When the wings are lowered, the volume of the body cavity decreases and, under the pressure of the internal organs, the air containing a lot of oxygen passes from the rear air sacs into the lungs, and the air from the anterior sacs into the trachea and is discharged outside. Thus, air passes through the lungs both when inhaling and when exhaling. The more intense the flight, the better the lungs are ventilated. When moving on land and at rest, breathing in birds occurs without the participation of air sacs.

Birds have a four-chambered heart (two atria and two ventricles). The large and small circles of blood circulation are completely separated (arterial blood enters the systemic circulation from the heart, and venous blood enters the small circle). The speed of blood circulation in birds is extremely high, which is associated with a high frequency of heart contraction.

The excretory organs of birds are bean-shaped kidneys. The resulting urine flows down the ureters into the cloaca and is excreted with feces.

Metabolism. Perfect breathing, the consumption of a large amount of food and its rapid digestion, a high heart rate and a rapid supply of nutrients and oxygen to tissues ensured a high metabolic rate in birds. Due to the feather cover, the release of heat to the external environment significantly decreased and the temperature of the birds became high (up to 43 ° C) and constant.

Nervous system. In birds, the hemispheres of the forebrain, midbrain and cerebellum are highly developed. With the development of the hemispheres of the forebrain, the rapid formation of various conditioned reflexes is associated, with the midbrain, the improvement of vision, with the cerebellum, the coordination of complex movements, especially during flight. The behavior of birds is very complex, which is manifested in the choice of nesting sites, building nests, protecting nesting territories, breeding and feeding chicks, the relationship of adults with each other, etc.

Reproduction and development of birds

Features of the reproductive organs. In females of most birds, the right ovary is underdeveloped and only the left one functions. The eggs in the ovary do not mature at the same time. The developed egg, passing through the oviduct, is fertilized by sperm introduced by the male into the female's cloaca.

The structure of the egg. Most of the egg is occupied by the egg itself - the yolk with the germinal disc (always facing up). After fertilization, the yolk is covered with protein, a two-layer subshell membrane (at the blunt end of the egg it exfoliates and forms an air chamber), a calcareous shell with numerous pores, and the thinnest suprashell membrane that protects the egg from the penetration of microbes.

Embryo development. The females of most birds lay their eggs in pre-built nests. A nest, even a hole in the soil, contributes to the compact arrangement of eggs, the preservation of heat and air humidity under the incubating bird. The development of the embryo in the egg occurs at a high temperature (about 39 ° C) and a certain humidity. The formed chick sticks its beak into the air chamber and inhales the air. It has a horny tooth on its beak. After breaking through the shell, the chick comes out.

Types of development of chicks. According to the degree of development of chicks hatching from eggs, birds are divided into brood and chicks. In brood birds (black grouse, hazel grouse, chickens, ducks), chicks are born sighted, covered with thick fluff. The mother hen leads them with a brood, warms them with the warmth of her body, gives danger signals, calls them to the found food, etc. In chicks (pigeons, starlings, tits), chicks hatch blind, naked or with sparse fluff.

Parents warm them in the nest with their warmth, bring them food, protect them from enemies.

Seasonal phenomena in the life of birds

Bird nesting. In spring, birds choose nesting sites, build or repair nests, females lay eggs in them, and then incubate them. Most often, birds nest in separate pairs and protect the selected territory from the invasion of individuals of their own and related species. With a limited choice of nesting sites and the ability to forage from a large area, some birds (rooks, sand martins, black-headed gulls) nest in colonies. In some birds, colonial nesting arose as an adaptation for joint defense against enemies.

post-breeding period. The second important seasonal phenomenon in the life of birds is molting. As a rule, it occurs gradually, and the birds do not lose their ability to fly. Only in some (geese, ducks, swans) during molting, all primary feathers fall out at once, and birds cannot fly for several weeks. In the post-nesting period, the birds gather in small flocks and roam in search of food. Some of them (nutcracker, jay) store food for the winter. At the end of summer and autumn, post-breeding migrations intensify and gradually, in some bird species, they turn into autumn and winter migrations, and in others, into autumn migration. According to the development of seasonal movements, birds are divided into sedentary, nomadic and migratory.

Sedentary and nomadic birds. Sedentary birds (house sparrow, jackdaw, rock dove) live in the same area, have adapted to the transition from one type of food to another, the use of human kitchen waste. Magpies, black grouse, capercaillie, hazel grouse, tits are close to sedentary birds.

Nomadic birds (woodpeckers, nuthatches, bullfinches) move away from summer habitats for tens and even thousands of kilometers. They do not have permanent wintering places and repeating routes of movement. By the end of winter, wandering birds usually approach their former nesting sites.

Migratory birds (orioles, swifts, ducks, geese, cranes) fly for wintering and nesting sites along the migration routes that have developed over the centuries. The main signal of the flight is the decrease of the day.

Ways to study bird migrations. Knowledge about wintering areas and flyways of birds was obtained by banding. Recently, miniature sensors attached to the bird's back have been used. Knowledge about bird migration is necessary for their protection and sustainable fishery.

Origin of bird migration. Scientists believe that bird flights arose several hundred millennia ago, when seasons began to set on Earth with climate change in temperate latitudes. The main reason for the occurrence of flights is the lack or absence of food in nesting areas during the cold season.

Origin and major orders of birds

Similarities between modern birds and reptiles. Modern birds and reptiles have a number of similarities: dry skin, scaly cover (in birds on the legs), cloaca, eggs are rich in yolk and have parchment-like or calcareous shells, development without transformation. In modern tropical birds, hoatzins, chicks have fingers with which they cling to tree branches. All this indicates that modern birds and reptiles are related groups of animals and have common ancestors.

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First birds. An important proof of the origin of birds from ancient reptiles is the fossilized imprints of the skeleton and feathers of one of the ancient birds, called the first bird, or Archeopteryx. The first bird was the size of a magpie. Jaws with teeth, a long tail with 20 vertebrae resembled reptiles. Their forelimbs had all the signs of bird wings. The tarsus was developed on the hind limbs, the fingers were located, like in birds, - three fingers forward, and one back. The first birds originated about 180 million years ago from ancient reptiles that ran on the ground on their hind legs, could climb trees, jump from branch to branch.

The most important orders of birds. In the class of birds, about 30 orders have been identified. The largest of them is the detachment of passeriformes. It includes different types of larks, sparrows, swallows, wagtails, starlings, crows, magpies, blackbirds. Passerines are most numerous in forests. The legs of the birds of this order are four-fingered (three fingers point forward and one back). During the nesting period, they live in pairs, building skillful nests. Chicks are born naked, helpless.

Of the other orders of birds, the largest in terms of the number of species are Charadriiformes, Anseriformes, Galliformes, Falconiformes, and Storks. The order of shorebirds includes woodcock, lapwing, plover, carrier and other sandpipers - small and medium-sized birds with long legs and a thin long beak. They live in wetlands, along the banks of rivers and other bodies of water. Sandpipers are brood birds. They feed mainly on invertebrates.

Anseriformes include geese, ducks, and swans. These waterfowl have dense plumage with developed down, a large oil gland, and swimming membranes between the toes. The edges of the wide beak are with teeth or with transverse plates forming a filtering apparatus. Many dive well, getting food from the bottom of the reservoir.

The order of galliformes (grouse, black grouse, capercaillie, quail, partridges, pheasants, wild bank and domestic chickens, turkeys) includes birds with strong legs adapted to raking the soil or forest litter when foraging, short and wide wings, providing a rapid take-off and a short flight. They lead mainly a sedentary or nomadic lifestyle. Galliformes are brood birds. Chicks feed mainly on insects, worms and other invertebrates, adults are mainly herbivorous.

The order of storks (storks, herons, bitterns) combines birds of medium and large sizes with a long neck and long legs. They feed on damp meadows, swamps or in the coastal parts of water bodies with amphibians, small fish, and mollusks. They usually nest in colonies.

The falconiformes order includes falcons, hawks, kites, eagles. They have strong legs with sharp, curved claws, a hooked beak, and sharp eyesight. The wings are either narrow, sharp, contributing to rapid flight, or wide, allowing you to soar in the air in search of prey. The chicks of these birds hatch from eggs sighted, covered with thick fluff.

The group of woodpeckers includes the large and small spotted woodpeckers, the green woodpecker, the black woodpecker (zhelna), and the wryneck. They have a sharp chisel-shaped beak, a long sharp jagged tongue, elastic ends of tail feathers bent towards the support, legs with two fingers pointing forward and two backwards, which allows them to hold well on tree trunks. The exception is the wryneck, which has a straight and weak beak, the tail rods are inelastic. Woodpeckers are nesting birds, hollow-nesting birds.

Ecological groups of birds

The main ecological groups of birds. This or that habitat is inhabited by birds of different orders. In connection with adaptation to life in similar conditions, they developed similar features of structure and behavior, and ecological groups of birds were formed: birds of the forest, birds of marshes, fresh water bodies and their coasts, birds of open desert-steppe spaces, birds of open air spaces, diurnal predators.

Birds of the forest live in spaces bounded by trees and shrubs. In such conditions, they developed adaptations for rapid takeoff and precise landing on branches, maneuvering between trees (shortened wide wings, rather long tail).

Small birds feeding mainly in the crowns of trees and shrubs (tits, kinglets) have thin and sharp beaks, tenacious toes with sharp claws. Woodpeckers and some passerines (pikas and nuthatches) have stiff tail feathers with sharp peaks, a rather strong beak, short legs with tenacious fingers that help to hold onto tree trunks when obtaining food. The birds of the lower tier of the forest (grouse, black grouse, hazel grouse) have developed adaptations for feeding on the ground.

Birds of swamps, coasts and open areas of fresh water. Some of the birds of this group (herons, bitterns, storks) usually feed in swamps, damp meadows, and in the coastal part of reservoirs. They have a long neck, thin long legs. Birds that forage in open areas of water bodies (ducks, teals, geese) have dense plumage, highly developed fluff and subcutaneous fat, a developed oil gland, short legs with swimming membranes, and a wide beak with a filtering apparatus.

Birds of the steppes and deserts (African ostrich, bustard, little bustard) have keen eyesight, a long neck, well-developed legs, allowing them to notice danger in time and hide from enemies. The bustard (males weighing up to 16 kg) and the little bustard (body weight up to 1 kg) living in the steppes of our country are rare birds. The main reasons for this are the plowing of the steppes and poaching.

Birds of open air spaces - swallows (village, urban, coastal), swifts - spend most of their active life in the air. The rapid flight of these birds is facilitated by long narrow wings, strongly developed pectoral muscles, and a notched tail - a rudder during flight. On the fly, they catch insects with a wide-opening mouth.

Diurnal predators (eagles, falcons, hawks, kites) live in various habitats - in forests, mountains, and on the plains. Any diurnal predator can be recognized by a strong hook-shaped beak, powerful legs with strong fingers and curved claws. Among them are scavengers, such as vultures and vultures.

Types of poultry. poultry

The importance of birds in nature and human life. Birds hold back the increase in the number of insects - pests of plants, carriers of pathogens of animals and humans, small rodents. Many of them destroy the seeds of weeds, contribute to the spread of seeds of mountain ash, cedar pine, oak acorns, etc. They and the eggs they lay are included in the food chains of many animals, some reptiles.

Ducks, geese, woodcocks, snipes, great snipes, quails, pheasants as objects of sport hunting, hazel grouses, black grouse, capercaillie and some other birds as objects of trade are of great interest to a person.

Bird protection. In order to preserve the number of birds in our country, strictly defined hunting periods have been established, and the capture of birds during their breeding and molting is prohibited. Places where rare birds are found have become protected areas. In recent years, special attention has been paid to the protection of such rare birds as bustard, little bustard, white crane, white-tailed eagle.

Every person should take care of the birds. The most accessible ways of caring are the manufacture and hanging of artificial nests (hollows, cracks, titmouses), planting hedges of thorny bushes around gardens in which various insectivorous birds nest, feeding birds in winter.

Types of poultry. Man has domesticated a small number of bird species, primarily for the purpose of obtaining meat, eggs, feathers and down. Chickens, ducks, geese, turkeys, and guinea fowls are of the greatest importance in the human economy. The first place among poultry is occupied by chickens. They have tender tasty meat, carry a lot of eggs, they can be kept in a limited area. The ancestor of domestic chickens is the wild Banking chicken. She still lives in the forests of India, Burma and the Malay Archipelago.

Verification work on the topic "Bird class"

Option 1

1. Scientists suggest that birds are descended from:

2) reptiles;

3) amphibians;

4) mammals.

2. The place of attachment of the tail feathers is:

2) sacral vertebra;

3) coccyx;

3. The spine of a bird consists of departments:

1) trunk, lumbar and tail;

2) cervical, thoracic, lumbar, sacral, caudal;

3) cervical, trunk, sacral, caudal;

4) cervical, thoracic and sacral.

4. Part of the respiratory system of birds are (is):

2) air bags;

3) flying muscles;

5. The group of nomadic birds includes:

1) sparrows;

2) pigeons;

3) crows;

4) bullfinches.

6. Night predator is:

1) sparrow owl;

2) titmouse;

3) tangerine;

7. Birds lack:

1) sternum;

2) cloaca;

3) bladder;

6) skin glands.

8. Why is the flight feathers of the eagle owl fringed?

9. Name the ancestor of modern breeds of domestic turkeys.

10. Why do birds need a coccygeal gland?

11. What are the flying muscles attached to?

12. How many sacral vertebrae do birds have?

13. What is the peculiarity of the structure of the reproductive system of birds in females?

14. What bones does the skeleton of the hind limb of birds consist of?

Test work on the topic "Birds"

Option 2

1. The transitional form between reptiles and birds is:

1) coelacanth;

2) stegocephalus;

3) Archeopteryx;

4) platypus.

2. The organ of hearing in birds consists of:

1) inner ear;

2) outer and middle ear;

3) inner and middle ear;

4) outer ear.

3. Contour wing feathers are called:

1) filiform;

2) flywheels;

3) covering;

4) steering.

4. The heart of birds consists of:

1) two ventricles and one atrium;

2) two atria and one ventricle;

3) two atria and two ventricles;

4) one ventricle and one atrium.

5. Sedentary birds of the European part of our country include:

1) black swift;

2) barn swallow;

3) house sparrow;

4) finch.

6. Night predator is:

2) gray owl;

3) tangerine;

7. Specify the adaptations of birds for flight:

1) hollow bones;

2) the presence of a cloaca;

3) the presence of a feather cover;

4) absence of skin glands;

5) presence of goiter;

6) the presence of a keel.

8. Name the ancestors of modern breeds of domestic chickens.

9. Why do geese and ducks sit shallow in the water?

10. Due to what is the strength of the support system of birds achieved?

11. What is the name of the lower part of the legs of a bird?

12. How many vertebrae does the cervical region of birds consist of?

13. Why is the cerebellum very large in birds?

14. What bones does the skeleton of the forelimb of birds consist of?

Answers to the test work on the topic "Bird Class"

it is a silent flight

North American turkey

its secret is used to lubricate feathers and prevent them from getting wet

2 vertebrae

consists of one - left - ovary and left oviduct

one femur, fused bones of the lower leg, bones of the foot, forming a tarsus and four fingers

banking chickens

the thickness of the feather cover is large, and there is a lot of air between the feather and down

due to the fusion of many bones even in the early stages of individual development

9 - 25 vertebrae

due to the complex movements of birds that require coordination during flight

one humerus, two bones of the forearm (ulna and radius), several bones of the hand and three underdeveloped fingers

Downy feather - the shaft is short, there is no second-order beard. If the shaft of a downy feather is so shortened that the beards move away in a single bundle - this is actually down. Feathers are shed regularly. Distributed unevenly.

3. Musculature: the chest muscles are especially developed (large pectoral - work - lowering the wings and subclavian - raising the wings) - in flying and muscles of the hind limbs - in non-flying.

4. Skeleton light (due to pneumaticity), durable (due to coalescence). Skull without seams, thin-walled, huge eye sockets, toothless jaws.

Spine consists of the cervical, thoracic, lumbar, sacral, caudal regions.

Cervical- up to 25 vertebrae, long, very mobile.

pectoral- fused, carry ribs, which are attached to the sternum with their ends and form the chest. Edge - consists of two parts - one is movable connected to the vertebra, the other to the sternum. Both parts are movably connected to each other. The upper part of the rib has a process that overlaps the adjacent rib - additional strength of the chest is achieved, while maintaining mobility.

The chest has a high ridge - keel - a place of attachment of muscles.

Lumbar(vertebrae are fused) the department fuses with sacral department (the vertebrae are fused), with the ilium, forming a characteristic for birds complex sacrum . This also includes part of the tail vertebrae. It has an important adaptive value in connection with the support of the body only on the hind limbs.

Tail the department ends with a bone plate - the coccygeal bone, which is the basis for attaching the tail feathers. The pelvis of birds is open - the bones of the pelvis below are not connected.

Forelimb belt - 3 paired bones: crow, shoulder blade, clavicle. The clavicles fuse at their lower ends and form fork .

Wing skeleton - the humerus, forearm and several bones of the hand, has three fingers, several small bones fuse into one and form a complex bone - this department has sufficient strength, since it carries a large load.

Rear limb belt - consists of 3 pairs of pelvic bones, which fuse with the lumbar, sacral and first tail vertebrae.

hind limb - thigh, shin, tarsus (consist of the tarsus and metatarsus) and 4 fingers (3 facing forward, 1 back).

5. body cavity - protected by the chest and wide pelvis, it contains all the internal organs.

6. Digestive system: oral cavity (no teeth), pharynx, esophagus with goiter (in some), stomach (glandular and muscular), intestines (thin and thick with blind outgrowths), cloaca. There is no rectum. High intensity of digestion is an adaptation to flight.

7. Respiratory system: lungs - dense spongy bodies. Respiratory tract: larynx, trachea, bronchi, bronchioles. Part of the branching of the bronchi forms thin-walled sacs - air bags - between internal organs, muscles, under the skin, inside the tubular bones of the skeleton. Available voice box .

Breathing in flight - carried out by lowering and raising the wings. When the wings rise, the air sacs expand and air enters them through the lungs.

When the wings are lowered, the air sacs are compressed, and the air again passes through the lungs. Thus, gas exchange occurs both during inhalation and during exhalation when passing through the lungs, this phenomenon is called - double breath . Provides continuous ventilation of the lungs. Also air bags - reduce friction, reduce bird weight, cool down.

8. Circulatory system: 4-chambered heart. First aortic arch, two circulations. The blood doesn't mix anywhere. High blood circulation rate (pulse 400-600 bpm), which ensures a high level of metabolic processes. Temperature - constant high 42-43ºС.

FOREWORD

Man tamed the wild rock dove over 5,000 years ago. Since then, pigeon breeders have bred many breeds of domestic pigeons, different in color, body shape and purpose. So far, no one has counted all the huge number of breeds of pigeons bred in different countries of the world. It is estimated that there are more than 800 of them.

Pigeon breeding combines sports, aesthetic pleasure, purposeful employment of free time, obtaining certain knowledge, educates a person in a true sense of love for animals and respect for nature.

Pigeon breeding is the only branch of poultry farming that is more related to the amateur than to the industrial agricultural sector. Only a new branch of pigeon breeding - meat pigeon breeding - takes on an industrial footing, and the rest remain entirely the work of individual amateurs and collectives - clubs and sections of pigeon breeding at the organizations of the nature conservation society.

All pigeon breeders are usually grouped according to the breeds of pigeons they breed.

Pigeon breeders-athletes hold competitions for their pets, train them. The best sports (mail) pigeons cover hundreds and thousands of kilometers on their way to their home, sometimes at a speed of more than 100 km / h.

Ornamental breed lovers breed purebred birds or work on breeding new breeds with a variety of shades of color and plumage pattern, unusual body and plumage shapes.

In the group of racing (flying) breeds of pigeons, each subgroup has a peculiar flight that is unique to it. Keeping each breed clean, preventing it from dying out or becoming purely decorative and losing its flying qualities is the task of amateur pigeon breeders of racing breeds.

Only meat pigeon breeding, mainly in developed countries, is not done by amateurs, but by farmers and entire industrial plants. But in our country, lovers of high-calorie dietary poultry meat are beginning to develop this industry, growing large and fast-growing pigeons for their table.

Charles Darwin's colleague, the English naturalist Huxley Thomas Henry, noted that pigeon breeding is "a high art, a great mystery, a matter that a person should not talk about lightly."

BIOLOGICAL CHARACTERISTICS OF PIGEONS

The issues of proper organization of keeping, feeding and breeding pigeons can only be solved on the basis of knowledge of the anatomy and physiology of birds. Knowledge in pigeon breeding is acquired by practice and observation, information from scientific sources.

Data on temperature, pulse, number of respiratory movements and other physiological parameters in adult pigeons: rectal body temperature (°C) - 40.6-42; pulse (beats per minute) - 140-400; the number of respiratory movements per minute - 25-30; the number of erythrocytes (million / cm 3) - 3.5–4.0; the number of leukocytes (thousand / cm 3) - 13-18.5, hemoglobin (%) - 15-16; sexual maturity - 6–7 months; duration of incubation of eggs (days) - 17–21. The number of respiratory movements, contraction of the heart muscle change dramatically at the moment of fright.

FITNESS FOR FLIGHT

In pigeons, like other birds, the body structure and biological characteristics are adapted for flight. The forelimbs are modified into flight organs - wings. The feather cover is well developed. Pigeons do not have teeth, a bladder, i.e., those organs that could make the bird heavier when flying. The spleen, liver, stomach are small in relation to body weight. The egg-forming organs function only at a certain time, and during the dormant period they are significantly reduced.

In terms of their mobility and ability to overcome space, pigeons occupy one of the first places among terrestrial vertebrates, their flight speed reaches 100 km / h. This causes intense muscle work and significant energy expenditure. Oxygen exchange in their body is fast and economical. The two-stage process of respiration arose as an evolutionary adaptation for the intensification of metabolism in the body. The work of the digestive organs is also connected with this - pigeons consume a large amount of food, and its assimilation proceeds quickly. These features are closely related to the presence in pigeons of a constant body temperature close to 42 ° C, the stability of which is provided by a heat-insulating cover of feathers.

The body of a dove is supported in the air by an aircraft. In general, the flight mechanism consists in the fact that the movements of the flying organs (wings) create air currents that lift the body of the bird and direct it forward. The tail plays the role of a rudder and directs movement in the right direction. The force of resistance that air exerts on the surface of the wings depends on the length and width of the wing and the speed of its flapping. The drag force is proportional to the square of the contraction of the wings. The ends of the wings experience the greatest resistance during flight. Experiments on the removal of four or five terminal flight feathers lead to the fact that the pigeon loses the ability to actively fly. In pigeons, depending on their breed characteristics, two types of flight are distinguished: rowing and sailing.

Rowing flight. The main aircraft is a wing, a one-arm lever that rotates in the shoulder joint. The attachment of the flight feathers and the peculiarity of their mobility are such that, when struck down, the wing almost does not let air through. When the wing rises, due to the bending of the axial part of the skeleton, the surface of the wing action on the air becomes smaller. Due to the rotation of the flight feathers, the wing becomes permeable to air. In order for a dove to stay in the air, its movements are necessary, that is, the wind created by the flapping of its wings. At the beginning of the flight, wing movements are more frequent, then, as the flight speed and resistance increase, the number of wing beats decreases, reaching a certain frequency. The flight speed of birds is very high: for example, a carrier pigeon accelerates to 18-19 m / s. When frightened, for example, when attacked by a falcon, the dove folds its wings and literally falls down like a stone, developing a speed of 70-80 km / h.

The maximum height of a pigeon flight is 1-3 thousand meters; higher, probably due to thin air, it is difficult for pigeons to fly. A kind of “butterfly” flight, in which the pigeons seem to soar in place, spreading their tail wide to slow down forward movement.

Sailing or soaring Pigeons use flight after climbing. Sometimes sailing is interspersed with rowing. The pigeon gains height where there is a constant movement of air currents, and creates a certain attack of oncoming air by the position of the wings. Periodically, pigeons connect the ends of the wings with an open wing and make a smooth flight in a circle.

musculoskeletal system

As a result of adaptation to flight, the skeleton of pigeons acquired a number of features: a significant part of the bones inside are hollow, contain air, but these bones are thin, hard and strong. Bone tissue contains many mineral salts, richly supplied with blood vessels, has a highly developed periosteum. Tubular bones are thin-walled, they branch into special sacs filled with air penetrating through the endings of the pulmonary bronchi.

When studying the exterior, it is necessary to know the location and shape of the individual bones that make up the skeleton. For example, on the skull of crested birds there is a bony outgrowth that serves as the basis for the crest.

The mass of the pigeon skeleton, according to V.P. Nazarov (1958), reaches approximately 9% of the total body mass.

A characteristic feature of the spine is the adhesion of most of the vertebrae, starting with the thoracic, which eliminates the bending of the pigeon's body during the flight and allows you to maintain a horizontal position. The bones of the pelvis form one large curved plate, to which the internal organs are suspended. The pubic bones are not fused, and the pelvis is open, which is associated with the ability of birds to carry relatively large eggs in a hard shell. These birds have 12–13 cervical vertebrae.

The last tail vertebrae fuse into a pygostyle, a bone to which the tail (tail) feathers are attached, and the previous tail vertebrae are movable, which ensures greater tail mobility. The tail plays an important role in the flight of a pigeon: it maintains balance, serves as a brake, that is, it performs the function of a rudder. The pygostyle is especially important for peacock pigeons, their tail consists of 28 feathers. A weak pygostyle is not able to hold such a tail, and it falls sideways, which is a serious fault.

A large sternum stands out, which creates support during flight for the internal organs, and the keel - the crest of the sternum - is the place of attachment of powerful muscles that set the wings in motion. Massive pectoral muscles reach 25% of the total body weight in flight breeds.

The wing is a modified forelimb of vertebrates, which in the process of evolution of the bird was reduced, that is, simplified. Of the fingers, the second, third and fourth remained, which, together with the humerus, ulna and radius, form the skeleton of the wing, its basis. The first finger, which existed in ancient birds and helped in climbing trees, turned into a winglet - a very important aerodynamic organ, similar to the slat of aircraft, without which normal takeoff and landing of a bird is impossible. The wing joints allow it to fold when not in use. The folded wing does not prevent the bird from moving freely on the ground, in tree branches, etc. In addition, folded wings, like two shields, protect the bird's body from extraneous influences.

Rice. 1. Dove Skeleton:

1 - cervical vertebrae; 2 - the first finger on the wing; 3 - metacarpus; 4 - the second finger; 5 - third finger; 6 - ulna; 7 - radius; 8 - shoulder; 9 - scapula; 10 - ilium; 11 - tail vertebrae; 12 - coccygeal bone; 13 - ischium; 14 - pubic bone; 15 - thigh; 16 - lower leg; 17 - tarsus (metatarsus); 18 - the first toe; 19 - fourth toe; 20 - sternum; 21 - sternum keel; 22 - abdominal part of the rib; 23 - dorsal part of the rib; 24 - coracoid; 25 - clavicle; 26 - thoracic vertebrae

The hind limbs are the support of the whole body when moving on the ground. The femur is powerful and short. The bones of the lower leg are almost completely fused, the tibia is reduced. The fusion of the bones of the tarsus and metatarsus forms the so-called tarsus. Of the four fingers, three are facing forward, and one is opposed. This structure of the hind limb gives the body greater stability and allows tenaciously grasping the support. Compared to other birds, the pigeon's legs are perhaps somewhat worse developed, the pigeon cannot jump like a sparrow or a crow, cannot run fast, cannot take anything with its paw or hold a piece of food.

In pigeons, the lungs are fused with the ribs, and the contraction of the intercostal muscles during flight automatically stimulates the work of the respiratory apparatus. This circumstance must be especially taken into account, since keeping pigeons in a sedentary state, without flying, makes them weak, prone to disease. Strong and healthy pigeons are always on the move, weak and sick pigeons sit ruffled. The physical condition of pigeons affects fertility.

The muscle tissue of birds is characterized by high density and fine fiber. Its structure in pigeons depends on the breed. In postal and high-flying birds, it is dense, in meat and decorative ones it is loose. The muscles of birds are divided into four groups: the muscles of the head, trunk, limbs and skin. They are attached to bones with tendons.

The location of the muscles in pigeons is peculiar. There are no muscles on the dorsal side of the body at all. Most of them are on the ventral side. The pectoral muscles, which move the wings, are especially strongly developed.

The pectoral muscles (torso) begin on the sternum and collarbone, end on the humerus. Their contraction sets the wings in motion.

The shoulder girdle in birds, which is a mechanical support for the wings, is very strongly developed and provides a strong connection of its constituent bones: the scapula, corcoid bone and clavicles. The latter have the shape of a Roman numeral V, play the role of a spring, protecting the body from being squeezed by the wings during the contraction of the pectoral muscles during the flight and the flapping of the wings. They serve in the same way as the pectoral muscles for the movement of the wings.

The chest consists of ribs attached to the spine and breastbone (keel). It is very strong and reinforces the shoulder girdle connected to the wings. The better developed the sternum (keel), the higher the pigeon is valued.

The pigeon's neck is mobile, as it consists of 14 vertebrae, which allows it to change direction during the flight. The thoracic vertebrae are inactive, the bones of the lumbosacral region are fused together, which is also a consequence of fitness for flight.

LEATHER AND ITS DERIVATIVES

The skin protects the pigeon from external influences: mechanical, thermal, chemical, etc.

The skin of pigeons, unlike the skin of mammals, is thin, dry, mobile, with a highly developed subcutaneous layer. It is loosely connected to the muscles, which allows it to gather into folds. The skin is not keratinized, scaly, in some breeds it is strongly feathered. One of the features of the skin of pigeons is the absence of sweat and sebaceous glands. Thermoregulation in pigeons is carried out due to air sacs, respiration, changes in plumage density (feathers fluff up from the cold) and regulation of metabolic rate.

Greater mobility of the skin of birds is provided by a loose subcutaneous layer, it accumulates fatty deposits, which are internal food reserves consumed by the body during certain periods (reproduction, molting). Fat layers soften blows and contribute to thermal insulation.

The derivatives of the skin include feathers, beak, claws. The metatarsus and fingers are covered with horny scales.

Plumage

The plumage performs various and important functions. It serves mainly to retain heat, creates a streamlined surface of the body and protects the skin from damage.

A feather is a very special formation that only birds have: light, flexible and dense, it makes it possible to fly. As a cover, the feather reliably dresses the bird, and on the outside it lies tightly, and in the depths a loose heat-insulating layer is formed from the fluff or the lower parts of the feather. Feather in the volume of the body of a bird occupies 60%, and by weight it is only 11%.

The feather is laid in the embryonic period; after hatching, the chick is already covered with sparse down, representing the top of the covering feather in its infancy. The feather is made up of stem, rod and fanned. The lower part of the fan is called the chin. It is shiny, horn-shaped, rounded, has a core in the form of separate funnels that enter one another. The lower part of the quill is placed in a feather bag and is connected to the feather papilla, which enters the quill. In this place, a side stem leaves with downy and semi-downy fans. The pen shaft is oval or faceted and filled with a hard spongy mass. Rays of the first order symmetrically go from the rod, and from them - rays of the second order, having hooks and cilia. Hooks and cilia interlock and form an elastic, fan-dense feather plate. Flight feathers of the first and second orders are long, elastic, dense. They are attached to the area of ​​the hand and forearm, have the shape of an elongated oval plate and are somewhat curved along the contour of the body.

contour feathers have a solid, elastic trunk and the same fan. Contour feathers include coverts, flight feathers and tail feathers. Coverts are usually somewhat convex and overlap tightly. Flight feathers are long, hard feathers attached to the carpal section of the wing and forearm. The number of primary primaries, or first order, is small - 10–12. The peculiarity of their structure is a highly developed, strong, asymmetric fan. Flight feathers of the second order with a symmetrical fan are attached to the ulna. Tail feathers form the bird's tail, arranged in one row, attached to the pygostyle. There are usually 10–12 of them, i.e., two feathers per vertebra. In thoroughbred pigeons, their number reaches 16, and in decorative peacocks - more than 36–38.

In addition to contour feathers, birds have simpler down feathers, in which the beards are not fastened, and feathers are almost without a trunk - fluff Pigeons do not have down feathers and down, they are replaced by the lower part of the fan with downy free beards.

Most birds have a coccygeal gland above the tail; birds, especially waterfowl, smear all feathers with its secretions so that they do not get wet. In pigeons, the coccygeal gland is poorly developed. But, in addition to ordinary feathers, there are also special powder feathers. These feathers, the ends of the beards of which constantly break off and form a fine powder - a powder that covers the entire plumage of a bird. Powder down - the smallest horn plates that easily absorb moisture - are located on the sides and uppertail of pigeons. The presence of powdered down determines the softness of the shades in the color of all pigeons.

A feature of birds, and in particular pigeons, is the ability to restore a plucked feather. A feather plucked between molts may grow back, but a feather plucked still undeveloped does not grow back well. An essential role in the restoration of feathers is played by nutrition, in particular the presence of proteins, minerals and vitamins. Feather growth also depends on the state of the nervous and endocrine systems.

Pigeons have patches of skin where the feathers are uneven, exposing it. Feathers are located on the skin along special stripes - pterylia, alternating with bare areas - apteria. With this arrangement, the feather lies more densely, muscle contraction and skin mobility during flight are facilitated.

Plumage color (solid, combination of white with color, pattern) is one of the hereditary characteristics of pigeons. Primary colors are blue (pigeon), black, red, yellow and white. Due to permanent variability, the number of combinations (patterns) can be indicated by a four-digit number. There are also so-called transitional colors: bronze, copper, silver, the color of chamois, boiled liver, ashen, fawn with belts on the wing shields (red, black, white). In addition to single-color, there are two- and three-color, speckled, scaly and many other colors and patterns in various combinations. Doves of Uzbek breeds are hatched in red or ashy, black and white, and after molting they change color and pattern.

The nature of the colors of the plumage of pigeons has long been of interest to researchers: many colors have already received their full definition. However, a much larger number still needs to be investigated.

The color of the plumage of pigeons is due to two types of pigments - melanins and lipochromes, which color the skin and feathers in the corresponding color. Melanins of gray and black tones are produced in the body and enter the feather during its growth. Lipochromes - dyes of plant origin, contain carotene, get into the pigeon's body with food. The colors they create range from ash-clay (yellow) to deep clay red. This pigment colors the beak, eyelid, metatarsus, bare skin around the eyes. The yellow color of the iris of the eyes of some breeds of pigeons is also due to the presence of lipochromes.

The white plumage of pigeons is called pigmentless. Brilliant, iridescent feathers on the neck - the optical effect of light reflection from the pigment base of the upper layer of the feather barbs. This is the result of the reflection and addition of light waves, and the pigment contained in the pen causes the appearance of certain shades of gloss: blue-green, metallic, pale purple in red rocks. This phenomenon is also observed in white doves.

Special attention must be paid to the integrity of the wing feather fan. They are often affected by feather-eaters, become polluted, especially in Lop-winged pigeons, as a result of which they lose their supporting strength and the ability to fly even over small distances, not to mention the height of flight.

Moult

Moulting is a natural process of annual feather change, but it is a little painful. It usually starts in July and lasts until October. Features of molting and its timing are a hereditary trait. In weakened or recovered pigeons, it proceeds slowly and painfully.

The change of feather proceeds gradually and in a strictly defined order, so that the pigeon does not lose the ability to fly, as is noted in geese and ducks. The change of the pen starts from the tenth flywheel, goes in turn to the outermost one. The secondary flight feathers begin to fall out when the six primary flight feathers are completely renewed. Between the feathers of the first and second orders, the so-called axillary feather grows on the border. The change of secondary flight feathers goes from the extreme ones in the direction of the shoulder joint. After the loss of half of the primary flight feathers, the change of tail feathers begins, which also takes place in a certain order: starting from the middle, two feathers fall out, then the next, and so on (Fig. 2).

The tail, consisting of 12 or more feathers, sheds simultaneously with the secondary flight feathers. Usually the tail is symmetrical in the number of feathers in it from the middle. Most breeds of pigeons have 12 of them. The second feathers fall out first from the middle. Then the two middle feathers are replaced, and then the rest in turn (in both directions). The second tail feathers on both sides are replaced last. The small coverts of the wing begin to change when the sixth primary feather falls out and are completely renewed before the change of primary feathers.

The change of small plumage is more intense than that of flight feathers. The molting of the head and neck is especially active, it is somewhat delayed on the sides, being the completion of the whole process. New feathers that have grown to replace those that have fallen out are easily distinguishable: they are lighter, brighter, and the fan is wider. The plumage of a healthy bird is abundant, dense, clean and shiny, covered with “powder” that remains on the hands from touch.

In the pigeons of the spring brood, the first molt, a partial change of feather begins at the age of three months and proceeds normally, in late broods it may occur next year. Such pigeons begin to fly much later than the early March pigeons.

Rice. 2. Scheme of molting of primary and secondary flight feathers

During molting, a new feather is formed deep in the skin under the dead feather, which pushes out the old one, so that it eventually falls out. However, it takes several days before the new feather pierces the skin and takes on its final dimensions.

Molting is a regularly repeated physiological process, which is strongly reflected in the course of metabolism. Pigeons at this time, as a rule, become lethargic, they have difficulty breathing, some have a yellow tongue, their eyes lose their inherent brilliance, sometimes the birds refuse food. During molting, pigeons require especially careful care and feeding. During this period, a little hemp or flaxseed should be added to the main feed, there should be plenty of mineral feed necessary for the formation of a feather. In case of poor appetite, domestic pigeons are recommended to give 1-2 grains of black pepper, and wild species - seeds of weeds and cultivated herbs.

The growing feather is intensively supplied with blood, therefore, when it is pulled out and broken off, bleeding may occur.

A pigeon with an open molt must be handled carefully so as not to hurt him and not to damage the tubes of the emerging new feather.