Bird class (AVES) General class characteristics. Scientists explained the shape of eggs from different birds What form is a body torso

Body shape. The adaptation to the flight led the relative monotony of the body shape. The torso is compact, more or less round. The head is small, the neck is long and movable. The forelimbs - wings - in calm state are folded and pressed against the sides of the body. The plumage ensures the flow of body. Specific variations in the size and shape of the beak and head, the length of the neck, the length and the shape of the wings and the tail, the length of the hind limbs and the shape of their fingers provide while maintaining the general monotony of the device to different types of motion and power supply.

Dimensions of birdsvarious in small limits; The possibility of flight limits the increasing size. The mass of large flying birds does not exceed 14-16 kg (swans, vultures, drofs) when the wings are wing to 3-4 m (pelicans, albatrosse). The smallest of birds are some Hummingbirds with a maximum mass of 1.6-2 g. The loss of the flight ability often leads to an increase in dimensions: the mass of large penguins reaches 40 kg, casual and African ostriches - 80-100 kg. Some of the extinct running birds reached the mass of 300-400 kg (epiornis, MOA).

Leather and its derivatives.The skin of birds is thin, dry, almost devoid of skin glands. Surface layers of epidermal layer cells are burned. The connective layer of the skin is divided into thin, but rather dense actual leather in which blood vessels pass, the endings (loose) of contour feathers are strengthened and the beams of smooth muscular fibers, changing the position of the feathers, and subcutaneous fiber - a loose layer directly adjacent to the torso muscles; In it is postponed fat stocks. The only skin gland is corking - lies on tail vertebrae. It produces a residential secret, standing through the ducts when birds are pressed on the gland beak. Birds are lubricated by this secret feathers, which contributes to the preservation of their elasticity and partly increases the water-repellent properties of the plumage. Fat sections of the smoke gland under the influence of sunlight are converted into vitamin D, which birds swallow when cleaning the pen. Copchic iron is well developed in most birds leading both a water and ground lifestyle (hurdled, chicken, etc.); Only in a few ground and water birds, it is developed weakly (cormorants, herons) or absent (ostrich-like, drofs, some parrots).

The growth of the eroded epidermal layer of the skin form corruses of the beak - Ramfotet. The horny flakes of the reptile type cover the fingers, the set, and sometimes part of the shin. The last phalanges of the fingers are covered with horny claws. The males of some birds (for example, in Pheasanov), a bone increases, covered with an acute horny case, is formed, covered with an acute horny case. Bird-specific feathered cover - also horny formations of the epidermal layer of the skin.

Main type of pen - contour feather. It consists of a durable and elastic horns, on the sides of which are mild outer and inner squeak. Part of the trunk to which the appeal is attached, called the rod; It has a fetched shape in the diameter. The bottom, deprived of the lap part of the trunk is called a whale and has a rounded section; Face base is immersed in the skin and strengthened in a feat bag. Each puffs are formed by the terminal with elongated cornea plates - the first-order beards, from which, in turn, bring numerous faded second-order beards (beells) with small hooks located on them. Crochets, enclosing with neighboring beards, form an elastic record of appeal. If, for example, when hitting, hooks will disperse and burst "burst", a bird, a beak, correcting the pen, will make hooks arrange again, and the pen structure will restore. Usually, in the bottom of the pen, the beard is thinner and fluffy, without hooks; This is the fluff part of the o'clock, the function of which is to hold the air layer at the skin. In sedentary birds, the winter feather has a more developed down part than the summer. Part of the birds (chicken, etc.) from the abdominal surface of the rod at the level of the lower edge, the addition rod, soft, branching beards also do not have hooks either. Development of downward rods increases the thermal insulating qualities of the pen.

Diverse Coloring birdsprovided both accumulating in a pen cells during its formation of pigments and microscopic features of the pen structure. The main types of pigments are melanins and lipochromas. Accumulating in horny cells of chucks and melanin grains determine the black, brown and gray lipochroma color in the form of fat droplets or flakes lie in a horn substance, providing red, yellow and green color. The combination in the same section of the pen of different pigments complicates the color. White color is due to air filled with an air colorless horn. Infeceding the Peru of many birds, a metallic gloss varying is created by the interference of light in the outer shells of horny cells. Pigments, painting pen, increase its mechanical strength. The painting of the plumage has a variety of meaning: facilitates the meeting of individuals of one species, prevents interspecific clashes, often makes a bird with an unimprovant in its usual habitat, etc.

Contour feathers, covering the whole body of the bird, strengthened in the skin on special fields - Pteryls, separated by the objects - areas of the skin, on which feathers do not grow. Such a layout of tiles-shaped feathers allows you to close the entire body with a minimum number of feathers. Only a few birds, preferably not flying (ostrich-like, penguins), feathers are evenly distributed over the entire surface of the skin. Long and especially durable feathers form a wing plane; They are called hoist. The primary handles are attached to the rear edge of the skeleton of the brush, minor - to the asshole side of the elbow bone. Flying feathers are located so that the outer foam covers only a part of the wider inner dust of the neighboring feather. When the wing is lowered, the feathers form a solid plane, reaching the air. When lifting the wing, the turns are somewhat rotated and the slots are formed between them through which the air passes. Long and durable feathers forming the tail plane are called steering.

Under the contour feathers are dying feathers; They have a thin rod, and the beards do not carry hooks, therefore the adhesive fence is not formed. Pooh is a downdoer pen, which has a sharply shortened rod and long, strongly pubescent beards are departed by a beam from the end of the obika. Pooh and down feathers either evenly cover the whole body (hussy, weakly, etc.), or are located only by targets (herons, owls, many sparrows). Pooh and down feathers provide thermal insulation. Many birds around the body have filamentous feathers with a subtle barrel and rare short beards. They serve as sensors that signal about air currents under the feathers. In the corners of the mouth, many birds are bristles; These are feathers with a elastic rod, lost beard. They perform a tactile function, and in part of species that catch small mining (goatoes, swallows, haircuts), increase the size of the oral hole.

The development of the pen. As a result of the growth of the cells of the epidermis and cutis on the skin, a tubercle is formed (it is similar to the scales of the scales of reptiles), gradually growing in the form of a directional increase in the growing back, the base of which is deepened into the skin, forming the pen vagina. The connective tissue of the growth turns into the nipple of the growing feather permeated with blood vessels. At the same time, the growing epidermal layer is differentiated to a subtle horny case, covering the growing feather, and a rod with beasts extending from it is formed from raging cells and gradually damaged cells. As the pen grows the surrounding His horny case gradually lisches, and the beards are straightened, forming frozen. Fully grown pen - a dead formation, held tightly adjacent to the wrap by the walls of the vagina and the muscular bundles of the corium. Their reduction allows you to change the position of the pen (to flush or, on the contrary, press the plumage). Papilla dry; From him in the flusher, the pen is only a film dusk.

Over time, feathers wear out and faded, their mechanical and thermal insulation properties deteriorate. Therefore, there is a periodic change of pen - molting. A complete link with a change of all feathers usually takes place at the end of the summer, after the completion of the reproduction. Usually, the flight abilities of birds do not significantly deteriorate.

However, some groups (hussy-shaped, shepherds, cranes, etc.) change the contour feathers by the body gradually, and flying and steering about their crumbling falls out at the same time, and the bird deprives the ability to fly (small ducks - about 20 days, swans - almost by 1.5 months); Linening birds are held in hard-to-reach places.

Part of the species in the year is not alone, but two molts. The second usually goes early in spring and captures not all the plumage: steering and flying are not replaced. The presence of two lines provides the possibility of a seasonal color change and quality of plumage. So, in the aunt during autumn molting, longer coating feathers are developing with a stronger than developed fluffy part of the octala and with a long, fluffy additional rod, which significantly increases the thermal insulating quality of the winter dress compared to summer. Smeted small birds in the winter dress has more feathers than in the summer, which also provides the best thermal insulation in winter: for example, in Chizhi in the winter outfit 2100-2400 feathers, and in the summer - about 1500.

Muscular system and main types of movement. Motion of birds are diverse: walking, jumping, running, climbing, swimming, diving, flying. They are provided by both changes in the musculoskeletal system and transformations of other systems of organ coordination and orientation in space creating the necessary energy reserves. A peculiar feature of the skeleton of birds is a well-pronounced pneumaticity of bones. Flat bones have a spongy structure, while maintaining greater strength with a small thickness. The tubular bones are also thin-wing, and the cavities inside them are filled with partially by air, partially - bone marrow. These features ensure the increased strength of individual bones and they will noticeably make them easier. However, it is necessary, however, to draw attention to the fact that the total weight of the skeleton is 8-18% of the body weight of birds - about as much as the mammals in which the bones are thicker, and there are no air cavities in them. This is explained by the fact that the birds relief made it possible to sharply increase their length (the length of the skeleton of the feet, and especially the wing is several times the length of the body), noticeably not increasing the total, the mass of the skeleton. As with other higher vertebrates, the skeleton of birds is divided into the axial skeleton and the associated chest, skull, the skeleton of the limbs and their belts.

Axial skeleton - The vertebral pole is divided into five departments: cervical, chest, lumbar, sacral and tail. The number of cervical vertebrae is changeable - from 11 to 23-25 \u200b\u200b(swans). Like the reptiles, the first vertebra - the Atlas, or Atlant, has the shape of the bone rings, and the second - the epistroinet - it is tested with a dental process; This ensures the mobility of the head relative to the neck. The remaining cervical vertebra of a heterocelle bird vertebral, the long body of each vertebral front and rear has a saddle-shaped surface (in the sagittal section of the vertebrae opistocels, and in the frontal - it is apring). The articulation of such vertebrae provides their significant mobility relative to each other in horizontal and vertical planes. The strength of the compounds of the vertebrae is enhanced by the presence of articular processes on the bases of the upper arcs forming the sliding joints. The cervical ribs of birds rudimentary grow up with the neck vertebrae, forming a channel for which vertebral artery and cervical sympathetic nerve pass. Only the last one or two cervical ribs are molded with cervical vertebrae, but they do not reach the sternum. Features of the cervical vertebrae, together with complex differentiated cervical muscles, allow birds to turn the head freely by 180 °, and some (owls, parrots) and 270 °. This makes it possible to complex and fast moving heads when setting the moving production, cleaning the plumage, building the nest; In flight allows, bending or blending the neck, within certain limits to change the position of the center of gravity, facilitates the orientation, etc.

Breast vertebrae in birds 3-10. They grow together with each other, forming the dorsal bone, and very tight joints are connected to a complex sacrum. Due to this, the body of the axial skeleton becomes fixed, which is important when flying (fluctuations of the body do not interfere with the coordination of air traffic). Ribs are rolled to breast vertebrae. Each edge consists of two departments - the spinal and abdominal, movably articulated with each other and forming an angle, vertex directed backwards. The upper end of the rebel roller is movably launched to the transverse process and the body of the thoracic vertebra, and the lower end of the abdominal department - to the edge of the sternum. Movable articulation of the spinal and abdominal departments of the ribs among themselves and the movable connection with the spinal column and the sternum along with a developed rib muscles provide a change in the volume of body cavity. This is one of breathing intensification mechanisms. The strength of the chest is enhanced by hooked outgrowths, reinforced on the dorsal departments and expanding to the subsequent edge. The large yard has the form of a thin wide and long plate, on which all birds (except ostrich-like) are located high keel sternum (Crista Sterni). Large sizes of sternum and its keel provide a place to attach powerful muscles moving wing.

All lumbar, sacrats (two) and part of the tail vertebrae are still growing with each other in the monolithic bone - a sacrifices (Synsacrum). In total, it includes 10-22 vertebra, the boundaries between which are not visible. With a complex sacrum, the bones of the pelvic belt are fixed. This ensures the constancy of the torso section and creates a solid support for the hind limbs. The number of free tail vertebers does not exceed 5-9. The last 4-8 tail vertebrae merges into the Pygostyle bone flattened from the sides, to which the base of the steering feathers are attached to the fan. The shortening of the tail department and the formation of pigthiness provides a solid support tail while maintaining its mobility. This is important because the tail not only performs the function of the added carrier plane, but participates in the flight control (as a brake and steering wheel).

Skull of birdslooks like a skull of reptiles and can be attributed to the diapsey type with a reduced top arc. Tropibasal skull (the orclasses are located ahead of the brain), formed by subtle spongy bones, the boundaries between which are clearly visible only in young birds. This, apparently, is due to the fact that the connection with the help of seams is impossible due to a small thickness of the bones. Therefore, the skull is relatively easy. It is originally compared with the reptiles and its form: the volume is sharply increased. The brain box, the red, the jaws are deprived of the teeth (in modern birds) and form the beak. The displacement of the large occipital opening and the occipital miechel on the bottom of the skull increases the mobility of the head relative to the neck and the body.

A large occipital hole is surrounded by four styling bones: the main (BasiCipitale), two side (OCCIPITALE LATERALE) and top (supraoccipitale). The main and side occipital bones form the only (as well as the reptiles), the occipital sizes, articulated with the first cervical vertebra. Three ear bones surrounding the auditory capsule merge with the surrounding bones and among themselves. In the cavity of the middle ear there is only one hearing bone - piping. The sides and the roof of the brain box form a paired covered bones: scaly, dark, frontal and side wedge-shaped (laterosphenoideum). The bottom of the skull forms the coating main wedge-shaped bone, which is closed by the covering main temporal bone (Basitemporale), and the bevis-shaped parasphenoid (Rostrum Parasphenoidei). His front end is a couch, on the edges of which the Hoans are located.

The upper part of the beak - the cluster - is formed by strongly diverse and spilled forelimited bones. The comb's comb, strengthened with the nose bones, is connected to the frontal bones and the front wall of the orbit formed by the outstanding average olfactory bone (MesetHmoideum). The constituents only the back of the impulvement of the maxillary bones merge with the sky bones. A thin bone crossbar can grow to the rear-line edge of the maxillary bone, consisting of two spilled bones - zilly and square-zickie. This is a typical lower arc of a diapsey skull, which limits the back of the eye and the temporal hole. The square-pool bone is tested with a square bone, the lower end of which forms the articular surface for articulation with the lower jaw, and the elongated upper end of the joint is attached to the scaly and front bone. Sky bones ends are listed on the carria-shaped parameter of parasphneneoid and joints are connected to pairful wardoid bones, which, in turn, joint are associated with square bones of the corresponding side.

Such a building of bone sky is important for kinetism (mobility) of the impulvement characteristic of the majority of birds. When cutting muscles, connecting the felon-ahead of the orphanage, the lower end of the square bone is shifted forward and shifts both pacific and walled dice (their connection with each other can slide on the beak process) and square-zick and zickyl. The pressure on these bone bridges is transmitted to the base of the cluster and thanks to the bone abbot in the briefs area, the vertex of the impulve is shifted up. In the zone, the abnormal bones are very thin, and some species (geese, etc.) are formed herein. When cutting muscles connecting the skull with the lower jaw, the top of the beak shifts the book. The mobility of the bone sky in combination with complex differentiated chewing-muscles provide a variety of, finely differentiated beak movements when grappling production, cleaning the plumage, building the nests. Probably, the mobility of the neck and the adjustment of the beak to the diverse movements contributed to the transformation of the forward limbs in the wings, as they replaced some of the secondary functions they perform (help in seizing food, body cleaning, etc.).

The lower part of the beak is connected or the lower jaw - is formed by a merger of a number of bones, of which are larger tooth, articular and angular. The jewish joint form articular and square bones. The movements of the implity and connections are very clearly coordinated by the differentiated system of chewing muscles. The subsidiary consists of an elongated body that supports the base of the tongue, and long rozens. Some birds, such as dyatlov, very long horns are enveloped by the whole skull. When reducing the sub-band musculature, the horns glide along the connecting lodge and the tongue is extended from the oral cavity almost on the length of the beak.

The skeleton of the front limb, which turned into birds in the wing, was subjected to significant changes. Powerful tubular bone - shoulder - has a flattened head, which significantly limits rotational movements in the shoulder joint, ensuring the stability of the wing in flight. The distal end of the shoulder is articulated with two bones of the forearm: more direct and thin radiation and more powerful elbow, at the ass side of which the tubercles are visible - the places of attachment of the first-speed flying. Of the proximal elements of the wrist, only two small independent bones are preserved, which are connected with bones of the forearm. The bones of the dice of the wrist (carpus) and all the foam bones (Metacarpus) merge into the total metacarpus (carpometacarpus), or buckle. The skeleton of fingers is dramatically reduced: only two phalanges of the second finger are well developed, continuing the axis of buckles. From the first and third finger, only one short phalanx is saved. The primary handles are attached to the buckle and the phalanges of the second finger. The phalange of the first finger is attached by several feathers "wing".

Brush transformation (buckle formation, finger reduction, small joint mobility) provide a solid support of the primary hand, experiencing the greatest loads in flight. The nature of the surfaces of all joints is such that it provides light mobility only in the plane of the wing; The possibility of rotational movements is sharply limited. It protects the wing turning, allows the bird without effort to change the area of \u200b\u200bthe wing in flight and fold it alone. Connecting a brush fold with a shoulder joint of the skin fold - an aircraft (Patagium) - forms an elastic front edge of the wing, smoothing the elbow fold and preventing the formation of air curvatures. The shape of the wing characteristic of each species is determined by the length of skeletal elements and minor and primary handles.

Fixtures to flight The forelimbs are distinctly expressed in the belt. Powerful shredded shrouds are firmly connected by larger joints with the front end of the sternum. Narrow and long blades grow together with the free ends of the shreddes, forming a deep articular cavity for the head of the shoulder. The fortress of the bones of the shoulder belt and their durable connection with the sternum provides the wings of the support in flight. The elongation of shreddes increases the area of \u200b\u200battaching the muscles of the wing and takes forward, on the level of the cervical vertebrae, shoulder joint; This allows you to lay the wing side of the body alone and beneficially aerodynamically, for in flight the center of gravity of the bird turns out to be on the line connecting the centers of the area of \u200b\u200bwings (stability). The clavicle will be fused to the fork (Furcula) located between the free ends of the shreddes and the role of the shock absorber, softening the shock during the wing waving.

The hind limbs and the pelvic belt have conversions associated with the fact that when driving on land, all the severity of the body is transferred to them. The skeleton of the rear limb is formed by powerful tubular bones. The total length of the leg even in the "short-circled" species exceeds the length of the body. The proximal end of the thigh ends with a pelvic round head jointly, and at the distal end, the embossed surfaces are formed with a knee joint with bones. It strengthens the knee cup lying in the musculous tendon. The main element of the shin is a bone complex, which can be called the tibiotarsus, or the Tibiotarsus (Tibiotarsus), as it grows up to a well-developed large ber (Tibia), forming its distal end, the upper row of the bones are replied. A small bone (fibula) is strongly reduced and grows to the top of the outer surface of a large beritic bone. Its reduction is due to the fact that most birds are all elements of limbs move in one plane, rotational movements in the distal part of the limb are limited.

The distal (lower) series of bones is repulsed (Tarsus) and all bones of plus (metaTarsus) merge into a single bone - a set, or a plus-replous (Tarsometatarsus); Appendix appears, which increases the length of the step. Since the movable joint is located between the two rows of elements are repluted (between the bones, spilled with a large bertic bone, and elements included in the composition of the set), then it, like the reptiles, is called interbranch. Forengie fingers are attached to the distal end of the queest.

Like all terrestrial vertebrates, the pelvic belt of birds is formed by the growing three pairs of bones. Wide and long iliac bone growl with a complex sacrum. A sedlication bone is growing to its outer edge, with whom the rod-shaped pubic bone is growing. All three bones are involved in the formation of a masterpiece, which includes, forming a hip joint, the head of the hip. The pubic and sciatic bones in the birds do not grow together in the middle line of the body; Such a pelvis is called open. It makes it possible to postpone large eggs and, perhaps, contributes to the intensification of respiration, without limiting the mobility of the abdominal wall in the pelvic region.

The large surface of the pelvis and its durable connection with the axial skeleton provide support with rear limbs and create opportunities to attach powerful foot muscles. Long strong bones of limbs, a sharp relief of their joint surfaces, along with well-developed and differentiated foot muscles, provide intensive movement in a variety of conditions.
The muscles of birds is differently different, and its relative mass is greater than that of reptiles. This is due to the greater mobility of birds and a variety of their movements. The compactness of the body, due to the requirements of aerodynamics, is largely achieved by the fact that the most powerful muscles carrying out the movements of the limbs are located on the body, and their tendons go with the limbs. Strong development of ligaments strengthens the connection of individual elements of the skeleton. Very complex neck muscles, providing high head mobility, which is important and when grappling production, and in orientation, and in flight.

From the muscles of the front limb, first of all deserve two mentions. The plug-in muscle (Musculus subclavius) is attached on the shirt, the body and the crest of the sternum, and its tendon ends on the shoulder head; The reduction of this muscle raises the wing. Over it lies, attaching to the sternum and her Kil, to the shrocide and a shrine-shaped ligament, a large breast muscle (m. Pecturalis Major), lowered in flight wing; Her tendon is attached too to the head of the shoulder. Both big breast muscles make up from 10 to 25% of the total weight of the bird and exceed the mass of the connective muscles at 3-20 times. These muscles in birds flying rapid, maneuverable flight are especially great. In addition, the work of the wing in flight is managed by several more dozen smaller muscles located on the body, shoulder and forearm.

The movements of the hind limbs carry out more than 30 muscles. Larger of their wide grounds are attached to the pelvic bones, small muscles are located on the hip and lower legs. Located on the back surface of the shin, a deep finger bent (M.Flexor Digitorum Perforans) forms a tendon passing along the back of the interbranch joint and the set, and then divided into four branches and ending on the lower surface of the end phalanxes of the fingers. The surface of the end tendons and the bottom of wide connected vagina, through which they move, have cross-ribbing. When the bird sits onto the branch and squeezes the fingers, under the pressure of her mass, the tendons are pressed against the wall of the vagina, and their ribs are connected: the fingers remain in a compressed state and when a muscle relaxes. In order for this "automatic lock", you need to reduce the muscles - the extensors of the fingers. This allows birds to sleep, sitting on the branch, with a relaxed muscles.

The respiratory movements of the chest are carried out with the help of intercostal and other muscles of the body walls. Multiple muscles are carried out by the movement of the tail. Compared to reptile, birds are better developed by subcutaneous muscles, which allows you to change the position of the feathers in large areas of the body. Small muscular bundles of the corium change the position of individual feathers.

For birds, the accumulation in Mioglobin muscles is characterized, which makes it possible to create a reserve reserve of oxygen, utilized during the period of intensive work. The highest concentration of Mioglobin is marked in a large thoracic muscle, muscular muscular stomach and heart. The concentration of muscle hemoglobin is higher in birds flying active flight, diving birds and birds of highly. In all cases, however, the concentration of hemoglobin in the blood is higher than in the muscles.

Lazagne and jumpingin the branches with the help of the rear and partly of the anterior limbs and the use of wings for planning is such, apparently, the main methods of the movement of primitive ancient birds. And now most species in one degree or another are associated with crowns of trees and bushes. In the branches of birds usually move on with jumps, sometimes helping solitary wingspins. The usual paw structure for them is three fingers ahead, one back - allows you to firmly cover the branches. Further specialization to the woody lifestyle is often accompanied by a change in the structure of the paw - two fingers are directed forward, two backwards, which probably makes it easier to retention on the branches. Perfectly climbing parrots use for grabbing and powerful beak. Due to the sharp strengthening of the muscles of the legs, the development of strong fingers with sharp claws, especially small, species of birds mastered the cliffs along vertical trunks (crawls, food, etc.) and on the rocks. Strong paws with powerful fingers and sharp claws and a durable tail, which serves as an additional support, allow the warmlands not only to climb vertical trunks, but by holding in one place, to hammer the bark and wood.

Many types of wood birds collect feed and on Earth. Small species at the same time, as in the branches, jump (sparrows, etc.), and others go and run, alternately rearrange her legs (white shaking, rho, crow, etc.). The adaptation to a terrestrial lifestyle is often accompanied by shorter fingers, especially directed back (sometimes it is reduced), the elongation of the set. The best runners among birds - who lost the ability to fly ostrich-like birds. The three-stage South American Nanda and a two-bed African ostrich can run at a speed of more than 50 km / h. In the inhabitants of the swamps and shores of the reservoirs (herons, shepherds, slices, etc.), the elongation of the vegetation and the tibia allows you to wander in shallow water, without wetting the plumage, and long thin fingers do not let fall on a viscous soil. At the Mustochhar, the Ryablik and other aunt during the autumn molting on the sides of the fingers grow horny hornies, increasing the area of \u200b\u200bsupport and reduce failures in the snow, and in white partridges on the fingers grow long feathers, turning the paw in skiing - snow wind. Many floating birds go to land (seagulls, etc.); Some of the good divers legs are far back attributed back and on land they almost can not move (Gagars, and leafing). Little and poorly go some well flying species (swallows, puffs, haircuts).

Bird class - warm-blooded animals whose body is covered with feathers (the only group of animals), and the front co-nonsense turned into wings; Fellows - legs. Birds fly beautifully, surpassing all other vertebrates in this regard. Also, birds are well moved along the ground, climb on trees, many dive and swim in water. Birds are extremely diverse in size, forms, painting, chants and adapted to habitat in various climatic conditions. There are about 9 thousand species.

The exterior structure of the bird

Birds have a head, neck, torso, limb and tail. The head of birds is small, there are beaks, eyes, nostrils. The beak is formed by the bone jaws stretched forward, which are covered with horny covers from above. There are no teeth in birds, which makes it easier to skull. At the base of the top of the beak are nostrils. Rounded eyes are covered with two centuries and a blinking meal. Ear holes are hidden under the neck under feathers. The movable neck connects his head with a compact torso.

Features Body Body

Signs	Body body features
Body shape	Thrust
	Dry skin covered with horny feathers
Types of Peryev	1. Contour - creates a body shape and helps when flying; 2. Down feather and fluff - keep warm
	Easy and durable due to: Estraging bones (bones brushes, pelvis, skull) Air cavities inside the bones of the aircraft muscles are attached to the keel (chest)
	Big chest (lower wings); Connected (raise wings)
Digestive system	Food digestion in 2-3 hours (rapid metabolism for maintaining a pedigree body temperature) Beak -\u003e Through -\u003e Esword (with Goobom) -\u003e Stomach (from two departments - muscular and ferrous) -\u003e Intestinal -\u003e Cloac
Respiratory system	Cellular lungs and additional air bags in body cavities and bones - to improve gas exchange and overheating protection. Double breathing.
Circulatory system	Four-chamber heart (two atrium and two joy-daughter), two circles circulation
Nervous system	The cerebellum is well developed; The hemispheres of the front brain are developed (complex behavior, instincts)
Reproduction	Internal fertilization, the female laying eggs containing the supply of nutrients for the embryo and protected by a limestone shell and a subseposition shell
Development of birds	Spring: formation of pairs -\u003e Changing of males -\u003e Nest -\u003e Singing eggs (from 1-2 to 15-20 pcs.) -\u003e On-sitting eggs -\u003e Caring for offspring. Chicks: 1. Out - appear dressed by Pup, with open eyes and can get out of the nest and follow the mother. 2. Nests - appear helpless, with strokes of eyelids, long do not leave the nests for a long time.

The most important detachments of birds

Troops of birds	Signs	Representatives
Sparrows	Basically forest birds, have four-pailed endings (three fingers directed forward, one back); Chicken poultry, in the nesting period live in pairs	Sparrows, Larks, Swallows, Skvorts, Crow, Drozda
Rzhanko-shaped	Brood poultry, live on the coasts of rivers, sampling places; Medium Sizes, Long Legs and Thin Long Beak	Kulik, Waldshnep, Chibis, Bekas
Gussey	In the edges of the beak are the cornea plates or teeth, and at the end of the beak there is thickening; Waterfowl you-vodka birds	Geese, ducks, swans
Penguins	The wings are narrow, unsuitable for the flight, there are plans on the paws, the legs are rented back, the skeleton of the tearing, the feathers are very thick	Imperial Pin Guine
Crane-shaped	Birds of open pro-wanders, have long legs and neck	Krasv-Krasvavka
	Large birds; have a challenge unsuitable for the field of wings and strong legs	African Ostrich
	Short rounded wings (fly hard), foot four-palm, with big claws and densely operen, beak relatively big	Ryabikov, Tetherov, Quail, Partridge, Glukhari
Day predators	Long sharp hook-shaped claws; the beak is short, swept; Flight quick	Falcons, eagles, hawks, vultures
	Nightly predatory birds, with aqueous curved beaks and outstanding claws, sensitive hearing and sharp vision, have loose and soft plumage, allowing you to fly silently	Filin, Owl, Sipuha, Owl-Spool

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Sourse of information:Biology in tables and schemes. / Edition 2e, - SPb.: 2004.

Having a high organization and capable (with rare exception) fly. Birds are widely spread on Earth, therefore they play an important role in the formation of a variety of ecosystems, as well as part of the economic activity of people. Modern science knows about 9,000 species of existing birds today. In different periods of the past, there were significantly more.

You can select the following generalfor birds characteristics:

1. The streamlined shape of the body. The front limbs are adapted for flight, not walking, so they have a special structure and are called wings. Rear limbs birds Serve for walking and as a support for the body.
2. Book of birds It has a small thickness, tubular bones have cavities with air, which facilitate the weight of birds and contribute to a smaller weight. This allows birds longer in the air. Skull in birds It does not have seams, it is formed from fascinated bones. The spine does not differ in high mobility - only the cervical department is moving.
   There are two features of the skeleton structure, characteristic only by birds:

   - Tsevka- Special bone that helps birds increase the width of her step;
   - Keel- Bone protrusion of the birds of birds, to which the flying muscles are attached.

3. Skin of birds Almost no glands, dry and thin. There is only copchicker glazewhich is located in the tail department. From the skin we grow feathers- These are horny formations that create and maintain microclimate in birds, and also help fly.
4. Muscular system of birds includes Many different types of muscles. The largest muscle group are falling thoracic muscles. These muscles are responsible for lowering the wing, that is, for the aircraft itself. Also well developed cervical, subcutaneous, intercostal muscles and leg muscles. Motor activity in birds is differentiated: they can walk, run, jump, swim, climb.
   Also exist two types of flying birds: soaringand mastery. Most bird species can fly to a huge distance ( migration of birds).
5. Baby respiratory organs - Lungs. In birds double breathing - This is when in flight the bird can breathe at the entrance and in exhalation, without choking in this way. When the bird is inhaled, the air falls not only in the lungs, but also in aerial bags. From air bags, it enters the lungs when exhaling.
6. Heart in birds four-chamber, capable of separating blood on arterialand venous. The heart quickly beats, wash the body with pure arterial blood. High motor intensity is inextricably linked with a high body temperature, which is supported at around +42 o C. Birds are already warm-blooded with a constant body temperature.
7. Poultry digestive system It has its own characteristics that are associated with the digestion of large volumes of often coarse food (grains, vegetables, fruits, insects, etc.), as well as relief the mass of the gastrointestinal tract. It is with the last circumstance that the lack of teeth in birds, the presence of goiter and the muscular ventricular, as well as shortening the rear of the render. So, there are no teeth from birds, therefore, in mining, I participates in the beak and language. Goiter in birds He served to mix food entering it, after which she goes into the stomach. IN muscular stomach department Food is peathed and mixed with each other and with gastric juices.
8. Birds allocation bodies, as well as the products of the final decay of urea in birds coincide with those in reptiles, with the difference that in the birds there is no bladder To reduce body weight.
9. Bird's brain It is divided into 5 departments. The greatest mass, respectively, the best development, have two front brain hemisphereswho have a smooth bark. A cerebellum is also well developed, which is associated with the need to have excellent coordination and complex forms of behavior. Birds are oriented in space through vision and hearing.
10. Birds are separate animalswho can already be observed sexual dimorphism. Females have left ovary. Fertilization occurs inside development of birds - Direct. Most bird species come with nests in which the eggs are laying. The female raises eggs throughout the time until the chicks are hatched, which then feed and teach fly. Chicks can be broken and nests - depending on how hatching chicks are well developed from eggs.

General characteristics. Birds - warm-blooded vertebrates from the group Amniota., adapted to flight. The front limbs are modified in the wings. The body is covered with feathers, which also form a carriage plane of wings and tail. Part of the bones of the plus and are prelundered, to drain, formed a single bone - the set. The skull is articulated with a spine with a single satellite. There are bark in the brain hemispheres, but their surface is smooth. The cerebellum is well developed. Light spongy, connected to the system of air bags. The heart is four-chamber. There is only the right arc of aorta, the left atrophies in embryonic development. Isolation authorities are pelvic kidneys. Internal fertilization. We multiply, laying eggs.

Currently, about 9 thousand species of birds inhabiting all the continents and islands live on Earth. In the USSR, approximately 750 species of birds live.

Modern birds are divided into three isolated over-detachments: Kielim birds (Carlnatae.) , Bulk Birds (RA.- titae.), Penguins { linpennes.).

Building and vitality. The appearance of birds reflects their fitness to fly (Fig. 247). The torso of the streamlined egg-shaped form is distinguished by compactness. The neck of most birds is thin, flexible. On the head forward is the beak consisting of an inclusion and connected. For flight, modified forefinders - wings are served. Most of their carrier plane form large elastic hoist feathers. Bird's feet take the whole severity of the body, when moving on the ground, climbing on trees, takeoff and landing. Feet have four departments: thigh, shin, queest and fingers. Usually the birds are four-piles, but sometimes the number is reduced to three and even two (African ostrich). Of the four fingers, in most cases, three are directed forward, and some are back.

Fig. 247. External (Field Lun)

Covers. The skin of the birds is thin, dry. Skin glands are absent. Only over the base of the tail in most birds there is a special cleaner iron, the secret of which is used to lubricate feathers, which prevents wetting. For birds is characterized by feathers. Feathers are inherent in all types of birds and are not found in other animals. Feathers of birds developed from the horny scales of reptiles.

Feather - derivative of skin epidermis (Fig. 248). It is formed by a horn substance - keratin. A separate feather consists of obika (part, immersed in the skin), rod and focused.

Fig. 248. Bird Nerner Building:

/ - rod; 2 - Outdoor foam; 3 inner roar; ■ / - trunk; 5 - Clean; 6 "- the opening of the wings; 7 meadow

Fig. 249. Bird wing structure:

/ - brachial bone; 2 - elbow bone; 3 ...... radial bone;

4 - Yiyatpo-Poppoppan bone; 5 ......... part of the wrist; 6 ", 7

phalanges of fingers; 8 - Wing; {.) wing membrane; 10 - the founding of flyer feathers; // - Primary fly feathers; 12 - Secondary fly feathers

The rod is a dense horny tube with a loose horny core. The first-order beards are supported from the rod in both directions, from which, in turn, short beards of the second order are departed. The beards of the second order carry small hooks, the lumping beards with each other, which is why the elastic light plate is formed, the feather appeared. In gentle dying feathers, the rod is shortened and carries thin gentle, non-hi-hooks beard. At the fluff, the rod is not developed and the beard moves a beam from the overall base.

Large elastic feathers forming the main part of the carrier plane of the wing are called fly. They are asymmetrically, the front side is narrow, and the rear is wide. Such a structure allows the passage of air between feathers when lifting the wing, and when lowering the air wing, a dense connection of feathers causes a dense air. Larger flies, leaving the bones of the wing brush, are called primary fly, and smaller in size and not so elastic feathers connected to the bones of the forearm, "- secondary handles (Fig. 249). Steering feathers, the congratulatory tail and the guides of the birds, They are distinguished by large sizes, elasticity and asymmetry Opayl. Smaller feathers, covering the body of birds, are called contour, they give the body a streamlined shape. The areas on which they are called are called Ptery Lyiy, and the skin sections, deprived of them, - theft (Fig. 250). Apliament is located in the middle line of the chest, in the axillary region, along the blades, that is, in those places of the body, where the skin over the muscles is tightened during flight. Appliances are covered with neighboring contour feathers. Many birds, especially water, between contour feathers Punched feathers and fluff, warming organism.

The role of feather cover in the life of birds is large and diverse. Fly and steering feathers form most of the carrier surface of the wings and the tail, therefore, they are necessary for flight. Feather cover gives the body body streamlined form, which facilitates their flight. Due to the high heat shield properties of feathers and aircrafts between them, feathers contributes to the preservation of the heat of the body of birds and, therefore, participates in the thermoregulation of the body. It also protects the bird from various mechanical impacts. A variety of feathers pigments give the birds to one or another coloring, which is often a patronage.

Periodically, usually once or twice a year, the feathers of birds are fully or partially updated by molting; At the same time, old feathers fall out, and in their place develop new (sometimes other color). Most birds have a linky plumage flows slowly and gradually, thanks to which they retain the ability of the flight, but with waterfowl, it flows so quickly that they cannot temporarily fly.

Fig. 250. Perstsji and Poultry ApTSrii (Pigeon)

Fig. 251. Bird skeleton (pigeon):

/ - cervical vertebrae; 2 - breast vertebrae; 3 - tail vertebrae; 4
- cork bone; 5, B.-Bar; 7 - Greet; S - Kiel; .V - blades; 10 - shrocid; // - clavicle (fork); 12
-- brachial bone; 13 - radiation bone; 14- elbow bone; 15 -

pyh; 16 .....18 - phalanges of fingers;

19 -21- pelvic bones; 22 - femoral bone; 23 - bone of the tibia; 24 - Tsevka; 25, 26 - Falanga fingers

The skeleton of birds is light and at the same time durable, which is important for flight (Fig. 251). It is easily achieved by the subtlety of the components of its bones and the presence of cavities in the tubular bones of the front limbs. The strength of the skeleton is largely due to the action of many bones.

The skull of birds is characterized by a large thin-walled cerebral box, huge eye sockets, zezless jaws. In adult birds, the bones of the skull completely grow out, which ensures its strength. The skull is articulated with the first cervical vertebra in one model.

The cervical vertebrae, the number of which in different birds varies, is articulated with each other saddle-shaped articular surfaces, which gives her greater flexibility. Breast vertebrae in adult birds are fought among themselves. Ribs lower ends attached to large chest bones; In the background, they have hooked processes that are laid by the ends on the edges of the next pair; This gives the chest strength. Bird's Birds, with the exception of those that have lost the ability to fly, carries a high bone keel on the front surface, which are attached with powerful breast and subclavian muscles on both sides, leading the wing.

Rear chest, lumbar, sacral and - front tail vertebrae in adult birds grow together and with thin iliac bones pelvis in a single cruster, which serves as a solid base for legs. The rear tail vertebrae merge, forming anchor bone having a type of vertical plate. It serves as a support for steering feathers.

The shoulder belt consists of three pairs of bones: saberoid blades lying along the spine; The busting clavits that are fucked by the lower ends in the fork, which is powered by the bases of the wings; Korakoids - massive bones connecting with one end with the blades and the bases of the shoulder bones, and the other with the sternum.

The skeleton of the wing consists of a large, hollow inside the shoulder bone, two bones (elbow and radial) forearm, a number of surrounded wrist stains and a foss and strongly reduced and modified phalanges II, III and IV fingers, I and V fingers atrophied, II has only one phalanx serving support for a separate feather beam at the outer edge of the wing, the so-called wing.

The skeletal pelvic belt is formed by thin iliac, pubic and sedable bones, growing in adult birds in a single bone. The rear ends of the pubic and sedal bones in the majority of birds (except for some ostrichs) are not converged, so the pelvis remains open from the bottom.

The skeleton of each of the hind limbs consists of a large bone of the hip, two bones of the leg (big and small ber), the sets and the phalanx of the fingers. Small bertovoy bone is strongly reduced and is increeding to a large ber bone. In the process of ontogenesis, the bones of the main row will grow to the lower end of the shin. The remaining bones are repulsed and three bones plus merge into a single elongated bone - set. Foreigns of fingers are launched to the lower end of the fence.

Musculature. Especially developed the chest and plug-in muscles leading in motion of the wings. Muscles of legs are also powerful, carrying out a lot of work when walking the bird and movement on the branches of trees, during takeoff and landing.

The nervous system, especially the central department, in birds has a more complex structure than reptiles, which corresponds to a higher level of vital activity. The brain of the birds is distinguished by the large sizes of the hemispheres of the front brain, the strong development of visual buggers of the middle brain and a huge folded cerebellum (Fig. 252). The roof of the hemispheres has a smooth surface, and the gray brainstant in it is weakly expressed. The strong development of visual bugs of the middle brain, carrying a visual function, is due to the importance of vision in the life of birds. The cerebellum is great and has a complex structure. Its middle part is a worm - the front edge almost comes into contact with the hemispheres, and the rear end covers the oblong brain. The worm is covered with characteristic transverse furrows. The development of the cerebellum is associated with flight requiring precisely coordinated movements. Head nerves in birds 12 pairs.

Digestive organs Beginning oral cavity. There are no teeth in modern birds - they are partially replaced by the sharp edges of the corneum cover of the beak, which the bird captures, holds and sometimes grinds food (Fig. 253). Long esophagus in many birds expands into goiter; Here the thread, drilling saliva, swells and softens. From the esophagus, "the feed falls into the iron stomach, which is mixed with digestive juices. From the ferrous stomach food goes into a muscular stomach. The walls are complicated by powerful muscles, and in the cavity lined with a solid shell, there are usually small pebbles, shredded by a bird. These pebbles and folds The walls of the stomach in the contraction of the muscles of the walls are eaten food.

The intestines of birds is relatively short. It distinguishes a longer thin and less extended fat departments. On the border of these departments from the intestine, two blind growing are departed. The rectum is not developed, so the feces do not accumulate in the intestine, which makes it easier for a lot of birds. The intestine is ends with a clock expansion, which opens up the ureters and ducts of the sex glands. The secrets of a large double-blade liver and pancreas entering the duodenum contribute to digestion.

Costs of birds during the flight of a huge amount of energy and the high level of metabolism determine the need to absorb large masses. So, the small bird of our forests of the queen in the day consumes the amount of food exceeding "/ 4 masses of the body. The processes of digestion take place in the birds very quickly: the whole intestines for 8-10 minutes pass on the rowan berries, and the duck, opened 30 minutes after how she swallowed a crucian 6 cm long, could not be discovered in the intestine of his residues.

Fig. 253. Internal structure of birds (pigeon):

/ - opened dove; // - incision of the stomach pigeon;

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

6 - a heart; 7 - iron stomach; 8 - Muscular stomach

Bird respiratory bodies also carry signs of adaptation to the flight during which the body needs enhanced gas exchange (Fig. 254). From the pharynx of the bird, a long trachea is departed, which in the chest cavity is divided into two bronchi. At the site of the separation of the trachea on the bronchi there is an extension - Lower lads, in which voice ligaments are located; Her walls have bone rings. Lower Mountains plays the role of voice apparatus and is particularly developed in birds singing or publishing loud sounds.

Light birds have a spongy structure. Bronchi, entering into the lungs, disintegrate into all the smallest branches. The latter end with the finest blind tubules - bronchioles, in the walls of which the capillaries of blood vessels pass.

Part of the Bronchi Branches goes beyond the lungs, continuing into thin-walled air bags 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 bird breathing during flight. In the siding poultry, breathing is carried out by expanding and compressing the chest. In the same way, when moving wings need a solid support, the chest remains almost fixed and the passage of air through the lungs is due to the main expansion and compression of air bags. This process was called double breathing, since the return of oxygen into the blood occurs both when inhaling and with exhalation. The faster the Mastery Flying, the more intense breathing. When lifting wings, they stretch and the air is sueded into the lungs and then in the bags. When lowering the wings, exhale occurs, and air passes through the lungs il.bags, which contributes to blood oxidation in the lungs.

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

Fig. 255. Bedroom Blood System (Pigeon):

/ Spicy atrial; 2 - right ventricle of the heart; 3 -Ul pulmonary artery; 4 right pulmonary artery; 5 - left atrium; 6 - left ventricle of the heart; 7 - the right arc of aorta; N, 9 -unnamed artery; 10 -12 - Sleepy arteries; 13 - subclavian artery; 14-- left chest artery; 15 - Aorta; 16 - right femoral artery; 17 renal artery; 18 - seedage artery; 19 -- iodine-shy artery; 20 rear mesenteric artery;
21 - tail artery; 22 tail vein; 23 - relight vein kidneys; 24 - femoral vein; 25 - iod-I! tire yen; 2 B.rear hollow vein; 27 -cain vein; 28
- Nadkinny Vienna; 29 renal vein; 30 - jugular vein; 31
- subclavian vein; 32 - front Hollow Vienna

The blood system of birds has two circles of blood circulation (Fig. 255). The whole heart is completely divided into the right and left half and has left and right atrium and left and right ventricles. This achieved the complete separation of arterial and venous blood flows. Arterial blood coming from the lungs but pulmonary vein falls into the left atrium, and from there - to the left ventricle, from which it goes to Aorta. Venous blood from all over the body enters the right atrium, and from it - in the right ventricle, so that later to go on the pulmonary artery to the easy.

In the embryos of birds, like reptiles, is laid as left and right arc of aorta, but in the process of embryonic development of the animal left atrophy. Starting from the left ventricle of the heart, the right arc of the aorta bends right (why it is called right), turns back and continues the aorta trunk stretching under the spine. Large paired nameless arterys are departed from the aortic arcs, which soon divide sleepy arteries, carrying blood to the head, and powerful chest and plug-in arteries going to the breast muscles and wings. From the spinal aorta, arteries are born to various parts of the body of birds and to the legs. The venous system of birds is mainly similar to that reptiles.

The high activity of the process of metabolism in birds makes it necessary to quickly and abundant supply of nutrients and oxygen in all parts of the body. Therefore, the blood circulation is performed very quickly, which is ensured by the energetic work of the heart. So, in many small birds, the heart is reduced more than 1 thousand times per minute (a person is 60-80 times).

Birds is also adapted to intensive metabolism in the body, as a result of which the volume of decay products to be removed is increasing. The kidneys in birds differ in large sizes and lie in the deepening of the pelvic bones. The ureterals opening in Cloacu are departed from them. The thick urine enters Cloaca, where it is removed from the feces.

Reproductive organs. Two seeds lying in the abdominal cavity have a bean shape. From them, the seed ranges opening in Cloacu. In some birds (geese), males have a comprehensive body. The females usually have only one, left, ovary lying near the kidneys. The egg came out of the ovarian falls into the unpaid ovage, in the upper part of which fertilization occurs. Having passed on the ovage, the egg acquires a protein shell, and hitting a wider uterus, covered with a limestone shell. Through the finite department of the female female, the vagina - the egg falls into the clock, and from there is displayed out.

Fig. 256. Bird egg structure:

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

air chamber; * "/ protein; L yolk sheath; inyolk; 7 - germs;
H ~white yolk; 9 -Hell yolk; 10 - Shalam

The bird's egg has (relative to the value of the animal) very large sizes, as it contains a lot of nutrients in the form of a yolk and protein (Fig. 256). The embryo is developing from a small embryonic disk located on the surface of the yolk.

On the blunt end of the egg, the IOD of the shell and a subsepted shell is a cavity filled with air; It helps the breath of the embryo. The development of the chick in the egg is shown in Fig. 257.

Fig. 257. Development of the Bird Embed:

/- IV - sequential stages of the development of the chmbridge; / - germ; 2 - yolk; 3 -protein; 4-- ashutyic fold; 5 sheep cavity; 6 "- air chamber; 7 - ~ shell; N-
serose; 10 - amnion cavity; // - Allantois; 12 ■- yellow bag

Ecology of birds. The main form of movement of most birds is flight. The adaptation to the flight caused a number of described changes in the structure of the body of these animals, and also imposed a fingerprint of all types of their livelihoods. Thanks to the ability to fly the birds, there are huge opportunities for distant migrations and settlements: it was the flight that allowed them to populate all the oceanic islands, often lying in hundreds of kilometers from the mainland. Flying helps birds avoid enemies. Many birds during the flight produce food or look out for her Pa Earth.

The nature of the flight of different types of birds is far from the same - it is always in accordance with their way of life. There are two main types of bird flights: a walker and a rowing flight. The parity is called flight of birds on more or less motionless, prostrate wings. This flight can be carried out with a gradual decline in birds in the air. But often the bird by saving can maintain a dialed height above the earth or even climb up (achieved through the use of the bird of ascending air flows). The rowing flight is carried out by the wings waving. In many birds, such an active form of flight alternates with a sacking in the air. The crow with a calm rowing field makes an average of 2.9, and a seagull - 2.2 waving wings per second. The maximum possible speed of the flight of the swallow 28 m, the plehahar- 16 and swan - 14 m per second. Some birds can fly without a stop for recreation more than 3 thousand km.

The ability to active flight, warm-bloodedness and high level of development of the central nervous system provided the birds of widespread on Earth. With the adaptation of birds during evolution to life in various conditions (forests, open spaces, water bodies), the formation of various environmental groups, characterized by the external appearance and specific features of the structure.

Wood birds - inhabitants of diverse forests and shrub thickets. This group includes dyatlas, parrots, ramp, food, cuckoo, starlands, frozards, pigeons, pleahari, rivets, etc. mining food and nest usually on trees, less often on Earth. The most specialized adapted to climb on the trees of birds (parrots, dyatlas, ramparts) is strong legs armed with curled claws. Dyatlov has two fingers ahead, two - back, which allows them to be cleverly climb on the trunks of the trees, relying on the tough and elastic feathers of the tail. Parrots are used when moving along the branches of trees not only the hind limbs, but also the beak.

Ground birds - inhabitants of open spaces - meadows, steppes and deserts. This group includes ostriches, drofs, streptags, some horses. Feed and nest on Earth. In search of feed moving mainly by walking and running, not a flight. These are large and medium sized birds with a massive and wide torso and long neck. Legs are long and strong, with short and thick fingers, the number of which can be reduced to three, and in the African ostrich - up to two.

Swamp birds inhabiting wetlands, swamps, overgrown with coarse reservoirs. Typical representatives: Herons, Storks, Cranes, Many Kuliki. Food is usually collected on Earth. Nests are arranged on earth or on trees. This is a large or medium poultry size. Most have long thin legs with elongated fingers, with which they easily move along a viscous soil or shallow water. The head is small, with a long solid beak. Wings are well developed. Tail short. The plumage loose, with a weakly developed Pup.

Waterfowl a significant part of life is carried out on water bodies. This group includes Gagars, Radiers, Cayra, Numbers, Penguins, Baklans, Pelicans, Ducks, Geese, Swans. They swim well, and many and dive, but go on land and are usually flying badly, and some do not fly at all (penguins). Many birds produce food (fish, mollusks, crustaceans) in water, others feed on land vegetative parts and seeds. They nest along the shores of the reservoirs, on Earth, Pa Trees, in the thickets of cane, on the rocks and in their crevices, in Norah. These are the large and medium size of the bird with a slightly flattened to the body and short tail. The legs are revealed far backwards, which provides almost vertical body position when walking. Have a dense plumage with well-developed down, swimming pools on the paws, most - developed cleaned gland.

Air-bird in contrast to the previous group, reservoirs are less related to a lesser extent. The group includes seagulls, paint, petrels. They usually fly well, float, but do not dive poorly. Flying soaring using air curvatures over waves or different air flow rates. They feed in the main fish, which is visited during the flight, then rapidly rush on it and pull out from the water with its strong and long beak, bent at the end. We often nest on the banks of rivers, lakes, seas, on the stony ledges of the sea shores. These are large and medium sized birds with an elongated torso, long, sharp wings and short legs, on which three fingers are connected by a swimming pool. The plumage is thick, with a lot of fluff.

Airborne birds a significant part of the day of time is spent in the air, where they catch their insects with their short, along a widely dropped beak. Typical representatives: haircuts, swallows, goatoes. These are excellent flyers with quick and maneuverable flight. It is usually nesting in buildings, in Norah but the banks of the rivers, on earth. Their body is an elongated shape, the neck is short, the wings are long and narrow. The legs are short, which makes it difficult to walk around the ground.

Nutrition birds. Most birds are animal people, others are roasting or omnivorous. There are species that are predominantly in vegetative parts of plants (geese), berries (thrills, waxes), seeds (sparrows, cheeks), nectar (hummingbird), insects (cuckoo, woody, many sparrows), fish (seagulls, cormorants, pelicans), frogs (ducks, storks, herons), lizards and snakes (storks, some day predators), birds (hawk), rodents (owls, many day predators). Some predators prefer to eat Padal (vultures, vultures, sics). The nature of food may vary depending on the age: most of the grainy-rod birds feed their chicks insects. The composition of the refinement varies on the season of the year. For example, the in the summer is feeding with green parts of plants, berries and insects, and in winter - mostly cheese pine, kidneys, shoots and birch and alderces.

Annual periodicity in the life of birds. In birds, as in other animals, the annual periodicity of life is closely related to seasonal changes in the conditions of existence and has a large adaptive value. It allows you to wind up the most responsible moment in the life of each type - reproduction - to a specific season, when the 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.

Preparation for reproductionit is expressed in the formation of steam. Association in marriage time in Nara (Monogamy) is characteristic of most bird species. However, the duration of the existence of steam among different birds is significantly different. For several years or maybe even lifelongly form pairs of swans, storks, eagles. Other birds form pairs for the breeding season, and many ducks are held by pairs only before the start of the egg laying. In a smaller number of bird species, the couples are not formed and the male for the period of reproduction fertilizes several females who bear entire care of the offspring. Such a phenomenon was named and O L H-Hamia (polygamy). It is characteristic of tetherov, pheasants, coarse, homemade chickens. In these birds, sexual dimorphism is especially well expressed.

Breakdown to the birds in birds is accompanied by a shocking: birds take various postures, unusually hold the plumage, make special sounds, some polygamy species occur between males. The marriage behavior of birds makes it easy to meet the singular sex and the formation of pairs, stimulates the synchronous ripening of the genital products of both partners.

The fertility of the birds is significantly less than reptiles, which is associated with the presence of a variety of forms of care for offspring in birds (nesting, building and feeding chicks). The number of eggs in masonry fluctuates from 1 (penguins, cake) to 22 (gray partridge). Most birds are based on their masonry. In polygamy species, the exercise is carried out only by the female (churo-shaped, huruing), the monogamous - alternately by the male and female (pigeons, seagulls, many sparrows) or only the female, and the male feeds it and protects the nesting site (owls, day predators, some sparrows).

The duration of incubation in different birds is different from the size of the egg and bird, the type of nest and the intensity of the accident. Small sparrows are based on 11 -12 days, crow - 17, swans - 35-40. The duration of incubation in domestic birds: the chicken 21 - day, the ducks - 28, at the geese - 30, at the turkey - 28, 29 days.

Depending on the degree of chicks, the birds have just hatched from eggs, birds are divided into brood, semi-consuming and chicks (Fig. 258). The chicks of broken birds are pubescent, vigorous, capable after a short time to feed on their own (churo-shaped, hurious, ostriches). The chicks of semi-high-consuming birds are hatched in vigorous and flooded, but they will be pumped up by their parents before purchasing the ability to fly (seagulls, numbers, petrels). In chicks, the chicks are bare, blind, remain in the nest (sparrow, dyatla, pigeons), where their parents are intensely fed them. So, a pair of mukholovok, a blue or foam brings food to its chicks up to 450-500 times a day.

After completion of the feeding of chicks, the family usually breaks down and birds are combined into flocks. The highest mortality is observed in the first year of the life of birds. Sometimes she can reach more than 50 % the numbers of individuals flying out of the nest. Pour birds reached at different ages. Most of the birds of small and medium sizes (many sparrows) begin to multiply the next year of life, larger birds (gray crow, ducks, small predators and seagulls) - on the 2nd year, and Gagars, eagles, petrels - by 3-4 -M, ostriches - on the 4th-5th year.

Fig. 258. Chicks of various birds at one age:

/ - chicks (bump); // - semi-recommended (eagle); /// - broken (partridge)

The average life expectancy of small sparrows is 1 - 1.5 years, and the limit - 8-10 years. Larger species of birds can live 40 years or more.

Linka differently flows from different birds. At some kinds (sparrows), it is gradual, in other (chiru-shaped, huruing) - violent. Line individuals of hussy-shaped for 2-5 weeks lose the ability to fly. Linka usually begins immediately after breeding. The males of many species that do not participate in the withdrawal of the offspring, molt occurs earlier than in females. Delaying males of dedication and tetherov are kept one in the deaf areas of the forest, and the deceases of ducks for the molting period accumulate in large quantities in hard-to-reach wetlands.

Preparation for winter . During this period, birds begin to walked in search of food. Intensive nutrition provides fat accumulation. Some birds are peculiar to the pope of feed, which makes them easier for wintering. Cuthes are harvested and drunk in the soil or under the forest litter of acorns, and the cedings are nuts. In winter, birds use these reserves only partially. Another part of the seeds is eaten by mile-like rodents and insects or, preserved until spring, germinates. Fresh and sinits hide seeds of various trees in the cracks of the cortex, providing themselves with food by 50-60%. Small owls (sparrows and amgnogo-legged owls) are harvested for the winter carcasses of miserable rodents and fold them into the hollow trees. Our storeroom birds find, apparently, thanks to memory and smell.

Zimovk but.In winter, poultry face with great difficulties in mining the desired number of feed. In search of habitats, which most fully can provide one or another type of feed and protective conditions, many birds begin to make directional movements (nomads and migration). Only sedentary birds remain in those places where their reproduction passed, and if they change their habitats, they fly away at no further than several tens of kilometers (Glukhary, Ryabchiki, Dyatlah, Sparrows, Tits). The coaching of the birds can fly away for hundreds of kilometers, the software usually hold within the same natural zone (Slistlee, Chechetics, Snegiri). The farthest migrations are committed by migratory birds, wintering in other natural zones that are thousands of kilometers from nesting sites.

The division of birds of sedentary, walkers and migratory is complicated by the fact that the same species in different parts of their range can behave differently. So, a gray crow in the south of the European part of the USSR is a settling view, on the south-moonful. Changing the weather and feeding conditions by year also affects the nature of the mobility of birds. In warm winters, with sufficient food provision, some faunions for this area remains wintering in places of their reproduction (ducks, gri, stuffing). This suggests that the main cause of bird flights is the seasonal changes in the conditions of existence. In areas where these changes, but seasons are pronounced, the number of migratory species is more. Thus, in the USSR from 750 species of birds 600 - migratory, wintering mainly in the British Islands, in Southern Europe, in the Mediterranean, in Africa and Asia.

Migration birds of birds are huge. The span path of our foos and swallows, wintering in Africa, is 9-k) thousand km, and the polar mask from the coasts of the Barents Sea to the coasts of Africa 16,800 km. The spans of waterfowl and swamp birds are confined to river valleys and sea coasts, where there are conditions suitable for their rest and feeding. Many birds flies with a wide front. Small sparrows cover a distance of 50 ..... 100 km, ducks - 100-

500, storks - ~ 250, Valdshnepa 500 km. During the day, the bird's flight is usually spent 1-2 hours, using the rest of the rest of the stop for recreation and feeding. Crossing water spaces, they fly off the distance of thousands of kilometers without rest. Spring bird stop is rarerging and short-term than autumn, so spring migrations usually occur at a greater speed than autumn.

Bird flights are one of the most interesting and weak-based bird biology issues. Until now, the mechanism determines the orientation of birds during flights has not yet been studied. Based on observations in nature and setting experiments, it was possible to reveal that migratory birds could navigate the position of the sun, the moon, stars, according to the landscape features. An important role in the migration behavior of birds and the choice of general directions is played by congenital migration instinct. However, it is manifested in the presence of a certain amount of environmental factors. Under the influence of environmental conditions, it is possible to change this congenital instinct.

Bird flights have developed for millennia. Undoubtedly influence the ice age on the formation of migration paths of birds in the northern hemisphere. Modern spans of some birds repeat the historical path of their settlement in the post-year-old time.

Of great importance for the study of bird flights has a ringing method, when the chicks before departure from the nest or adult birds are put on the paw metal ring with the number and designation of the institution conductive. In our country, all information about the ringing and mining of incenered birds is sent to the Center for the Ringing of the USSR Academy of Sciences (Moscow). About 1 million birds annually ring in the world, of which in the USSR - more than 100 thousand. Dogging allows you to trace the migration pathways, flight speed, lifespan and other important issues of bird ecology.

Economic value of birds. The role of birds in man's economic activity is large and diverse. Birds domesticated by man (chickens, geese, ducks, turkey, ceshards, pigeons), have long been used to obtain meat, eggs, fluffs, pen and other valuable products and industrial raw materials from them. In a fallen country, poultry farming is the most important and rapidly developing branch of animal husbandry. Many species of wild birds (chrooty, huruing, some horses) serve as sports and fishing hunting, which allows you to additionally involve a significant amount of delicious meat in the economic turnover.

The role of birds in the extermination of insects and miserable rodents - the pests of agriculture. The value of the cells, mukholoks, random, starling, droinds and many other birds as the number of harmful insects is especially increasing during the feeding period of chicks. Thus, the family of an ordinary squortzer for the nesting period destroys 8-10 thousand May beetles and their larvae or over 15 thousand caterpillars of winter spiders. Many birds predatory, owls, seagulls, storks and a number of others exterminate mice, voles, gophers, rats, hamsters and other harmful rodents. The usefulness of birds is associated with their ability to quickly find and concentrate in the foci of mass reproduction of pests, and for many species of birds - switch to numerous, although often not peculiar to feed. So, during the years of mass reproduction of mysterious rodents, the grits, seagulls and others begin to eat them.

Some birds act as distributors of plants. So, in the Taiga of Eastern Siberia Pa Garyakh, the recovery of cedar is often associated with the activity of the cedishment. Coyki \u200b\u200bparticipate in oak settlement. Sweetheli, Drozdda, Ryakchiki and many others spread rowan seeds, cherry, terns, elders, viburnum, bearende, blueberries, raspberries, lingers, etc.

Fig. 259. Different types of lomacions for the roads of useful insectivore birds

To increase the number and attracting beneficial birds, it creates favorable conditions for their nesting, artificial nestings hang out: Bunches, dupels (Fig. 259),

conduct winter feeding iT.d. With the suspension of the artificial nesting, the number of ITIC-Dulyohydroybanks (Mukholovka, Tits, Skvorts) increases sharply.

In some cases, birds can cause certain damage. The grits, useful to destroy soil insects, harm the crops of crops (especially the corn), operating seeds and pulling the seedlings. Washing Skvorts smell the mature fruits of cherry and grapes. In the southern regions of our country, there are serious harvests of grain crops. Golden church, exterminating bees, can bring harm to beekeeping. Hunting houses are harmful to reed Lun and gray crow. When a collision in air with high-speed aircraft, birds sometimes become the cause of serious accidents, which causes the creation of a system of scaring birds from the airfield territory. It is also necessary to take into account the role of birds in the distribution of some dangerous for humans and farm animals (ornithoses, flu, encephalitis, etc.).

Eggs of various types of birds differ in weight, painting, form and degree of symmetry. However, most of them have an oval, slightly elongated form with one more stupid and other - more acute end.

Hummingbirds are surrounding elliptical eggs, owls - round, and the rzhanks are drop-like, pointed from one end. The reason why birds of birds have a different form, interested scientists for a long time.

This question was asked even the Greek philosopher Aristotle, who mistakenly believed that the eggs, inside which the male chicks are developing, have a more pointed end.

The answer to this question was finally obtained by scientists from the titanic work on the study of eggs and came to the conclusion that the shape of eggs depends on the ability of birds of a separate type to flight.

According to one of the traditional explanations, the elongated shape of the eggs can interfere with them to roll out of the nests and allows you to easily pass through the cloac.

"Unlike classical hypothesis, we found that the flight can affect the shape of the eggs. Birds that fly well, lay asymmetric or elliptic eggs. In addition, we suggested that the soft membrane of eggs, and not their solid shell responsible for all the variety of their forms that we observe in nature, "Mary Caswell explained, the author of the study published in the journal Science. .

To understand the reason for the formation of eggs of different shapes among different birds, the international team of scientists conducted a multi-step interdisciplinary study using computer modeling methods and comparative biology.

To begin with, they studied photographs of about 50 thousand diverse eggs belonging to 1,400 different types of birds living now and already extinct. Samples were selected from the entire globe and stored in the database of vertebrate zoology museum in Berkeley, California. All of them were assembled by naturalists during the XIX and XX century.

In order to formalize the description of various forms of eggs, scientists have entered only two parameters - the ellipticity and the degree of asymmetry (the difference between the blunt end from acute). Using high-performance image processing tools, as well as descriptive data from the same collection, scientists were able to compose a "card" of various forms of bird eggs. Thus, the most asymmetric eggs turned out to have a sandbox-crumb, the most elliptical - in Maleo's birds from the island of Sulawesi, who lay them into the sand heated by the sun or volcanic ground.

scienceAlert.com.

The card helped note that birds having wings that allow them to make a flight efficient in terms of aerodynamics and fly away from the nest, have more elongated and sharp eggs.

"Variations between the size and shape of eggs in various types of birds are not just random, but are associated with differences in ecology, in particular - the ability of each species to a confident and elegant flight," the co-author of Joseph Tobias from the Imperial College of London explained.

Scientists believe that eggs are more elongated form appear in birds having a smoother, "aerodynamic" body intended for effective flight. Penguins that do not fly, but also have elongated eggs - rather an exception confirming the rule, since their body also has streamlined forms for the smallest resistance when swimming.

The same birds that spend a lot of time on Earth, often have more round eggs for which a wider egg is required.