How a bird is born. The sacrament of reproduction in chickens. The criteria for choosing a partner for all birds are different: it can be the strongest, the most colorful, loud, caring or the most hardworking. Relationships in bird pairs can be both fleeting and long-term.
Many novice farmers think about the question: how does a rooster fertilize a chicken. This is important to know in order to understand the process of mating, fertilization and, in general, reproduction of these birds. Many people know that the rooster often tramples the hens and thus the hens breed. A rooster can trample chickens throughout the year, except for the time of molting.
Mechanism of the mating process
Chickens are birds that live only in a flock and never individually. Any flock has its own rooster - the leader. The leader has access to any chicken at any time and can trample them as many times as he needs. If this right is somehow restricted by other males, then fights occur, sometimes ending in bloodshed.
Ritual games are an important stage in the mating process. The rooster does not immediately trample the chickens, at first he usually spins around the female and begins to lower one wing. After some time, he starts to stomp. In the process of mating, the rooster jumps on the chicken, tramples it and grabs the female by the feathers on the back of her head with her beak.
Chickens reproduce with the help of a cloaca - an expanded part of the intestine, which opens outwards with a hole under the tail. When a rooster tramples on a hen, the cloacae of the birds turn inside out and the testicles of the rooster come into contact with the cloaca of the hen. At the same time, seminal fluid is released, which enters the female genital tract. The seed is able to remain active in the genital tract of a chicken for about 20 days and all the eggs that she lays during this period will be fertilized and ready to hatch.
Mating proceeds very quickly, this process is often repeated. A healthy male is able to make up to 22 matings per day, the quality of sperm depends on the frequency of this process. If the rooster tramples the hens too often, then the sperm concentration drops significantly. Conversely, with a decrease in the number of copulations, the concentration of germ cells in the seminal fluid increases. In order to maintain flock numbers and ensure a high level of fertilized eggs, it is important to determine how many males should be kept in a flock.
As already noted, the male tramples chickens up to 22 times a day, this figure may decrease depending on the time of year and bird activity. It is generally accepted that in a flock of 10-12 chickens there should be one leader, if there are more of them, then fights will inevitably arise.
How does the fertilization of eggs take place?
The process of maturation of the egg occurs in the ovary of the chicken, before oviposition, its rapid growth begins. In this case, the shell of the egg (follicle) actively produces the yolk mass. At the same time, from 4 to 6 large yolks can be seen in the ovary of an actively rushing hen. When the egg is mature, the membranes rupture and ovulation occurs - the yolk falls into the funnel of the oviduct.
An experiment conducted in 1948 helped determine where in the oviduct fertilization occurs. He established that the unfertilized egg enters the oviduct and is fertilized when 20 minutes have passed after this point, in the upper part of the oviduct. There is no reason to believe that fertilization occurs in some other parts of the oviduct.
In the genital tract of the hen, the egg and the seed of the rooster meet. Seminal fluid is able to pass through the thin shell of the egg. From 20 to 60 germ cells penetrate into the egg at the same time, but only one of them fertilizes it. The penetration of the rooster seed is possible due to the fact that the shell has not yet had time to form by this time. The egg is covered with a hard outer shell only a day after fertilization.
The very contact of the sperm with the egg is accompanied by an acrosomal reaction, when a thread comes out of the body of the sperm, penetrating the egg. Next, the male reproductive cell enters the female. Only the head, carrying genetic information, penetrates inside, while the tail disappears.
How can you tell if an egg is fertilized?
When faced with the task of hatching chickens, it is important to determine whether the hen's egg is fertilized or not. It may happen that some of the eggs placed under the hen will not hatch. This is due to the fact that they do not have an embryo, that is, they are not fertilized and there is no hope of getting offspring. The fact is that hens rush in any case when there is a rooster or not. But they breed only in the presence of a rooster.
A fertilized egg can be identified by the presence of a small amount of blood in the yolk. In order to enlighten and determine fertilization, you can use ordinary light from a lamp or purchase a special device - an ovoscope (you can see what it looks like in the photo). You can also make it yourself if it is not possible to purchase the device.
The device for transillumination should be taken to a dark place. The egg should be laid with a thick end to the light, then tilted to get a good look at what's inside. It is most difficult to enlighten brown eggs, so it is better to choose white specimens for laying under the chicken. There is no need to look at the contents for a long time: thanks to the bright light, it will not be difficult to determine the embryo. In order to represent the whole process of transillumination, you can watch a video on the Internet on this topic.
In a fertilized egg, a small area with blood vessels is visible in the light. If no black dots and blood clots are observed when transilluminating the inside, then you have an unfertilized egg in front of you, it is not suitable for incubation. Sometimes it happens that it is impossible to determine the clot in the yolk, but the blood contour is visible along the edge of the yolk, but there are no spots in the center. This suggests that the egg was fertilized and the embryo began to develop, but for some reason it died. Such an instance should be thrown away immediately, the chicken will not hatch from it.
What to do if the rooster tore the back and sides of the chicken?
This situation, when roosters tear the backs and sides of hens during mating, is very common. The reason for this is that the rooster's claws are too large, so if possible, their excess should be removed. It is advisable to immediately wash the wounds with any disinfectant, for example, Chlorhexidine or ordinary peroxide, and lubricate with any healing ointment. It can even be common for people: zinc helps well, Vishnevsky, Healer and others. Until the back and sides heal, it is better to put such chickens away from the rooster or keep the “petka” separately from the chickens in the pen.
Video "Chicken Embryo Development"
In this video you will see how life is born inside a chicken egg.
In the smallest birds - some hummingbirds, having a mass of 1.6-1.8 g, an egg mass of about 0.2 g, in an African ostrich and large penguins, the egg mass is about 1.5% of the female mass, and in waders and small passerines birds - up to 15-20%. The fecundity of birds is noticeably less than the fecundity of reptiles, which is associated with a decrease in embryonic and postembryonic mortality due to various forms of care for offspring. Large predators, penguins, guillemots and small species of hummingbirds lay one egg. Pigeons, swifts, small penguins and auks, large hummingbirds, cranes, nightjars have two eggs in the clutch. Three eggs are laid by grouse and most gulls. Sandpipers usually have four eggs in a clutch. Most passerines lay 5-8 eggs, ducks - 6-14 eggs, etc. In diurnal predators and owls, clutch sizes increase with an abundance of food. The largest clutches - up to 22 eggs - are found in the gray partridge and quail. Large clutches - up to 10-15 eggs - are known for some small passerines: tits, wrens, etc.
Reproduction of each bird species timed to a certain season of the year so that the growth of chicks occurs during the most feeding period. In temperate and northern latitudes, reproduction begins in late spring - the first half of summer, in the tropics it is confined to the rainy season or (in some fish-eating species), on the contrary, to periods of drought. In temperate and northern latitudes, an increase in the length of daylight hours causes the secretion of gonadotropic hormones by the pituitary gland, under the influence of which the formation of germ cells begins in the sex glands. The final maturation of germ cells and the immediate start of reproduction (fertilization and oviposition) is determined by a complex of factors: favorable temperatures, sufficient food, the availability of suitable nesting sites, and the presence of a sexual partner.
All birds show some degree of sexual dimorphism. It manifests itself most clearly in many hens, anseriformes, passerines, when males are noticeably larger than females, more brightly colored, sometimes have a louder voice and a complex song. In other birds, it is expressed only in the fact that males are somewhat larger than females (in birds of prey and owls, females are larger than males). In most species, the male and female form a pair during the breeding season; in eagles, swans, geese, and large herons, pairs persist for several years, sometimes until the death of one of the partners, in others, for example, in many ducks, only during the period of oviposition. All these birds are called monogamous. In a smaller number of species - polygamous - pairs are not formed even for a short time and mating occurs during short-term meetings of males and females; usually they have a particularly pronounced sexual dimorphism. Polygams include capercaillie, black grouse, peacocks, waders, hummingbirds, etc.
Reproduction in all birds begins with mating games or current. Its manifestations are unusually diverse: these are the sonorous song of passerine birds, and the dances of cranes, and the drumming of woodpeckers banging their beaks on a dry branch, and the loud cries of owls, and the craving of a woodcock, etc. Monogamous in mating games to one degree or another both partners take part, but the male displays more intensively. In a few species, for example, in phalaropes, females lek; they are larger than males and brighter colored. In polygams, only males lek, in some species they gather in groups (black grouse, turukhtans, etc.). Current phenomena facilitate the meeting of a male and a female, contribute to the formation of a pair (in monogamous), provide physiological preparation of partners for mating. The distinctly expressed species specificity of current phenomena (postures and the general nature of behavior, sounds produced) prevents interspecific hybridization.
During the current period goes and nest building. In monogamous it is built by both partners or only by the female, and the male sometimes brings building material. In polygamous nests, only the female builds the nest. The nature of the nests and their location in the class of birds are extremely diverse, but in each species, in accordance with its ecological characteristics, the nests are relatively of the same type. Only very few birds do not build nests, laying their eggs directly on the ground (nightjars, some sandpipers) or on rock ledges (guillemots). Chickens and waders, gulls, owls, etc. cover the hole on the ground with bedding of plant rags. when leaving for feeding, they cover the eggs with fluff.
In the fork of the branches, careless nests of sketched dry branches with a meager grassy lining are arranged by diurnal predators, storks, herons, cormorants, and ravens; sometimes they build them in reeds, on rocky ledges, or on the ground. Many passerine birds are especially skillful in building nests, placing them in a fork of branches or on the ground. The dense bowl of the nest is twisted from dry blades of grass and thin twigs, and from the inside it is lined with soft stems, moss, selected feathers and wool. Some birds, such as finches, weave lichens and pieces of bark into its outer walls to mask the nest. Song thrushes smear the tray with saliva-soaked rotten wood, while other thrushes reinforce the walls with mud. In some species, the nest is a dense ball with thick walls and a side entrance, built in a fork of branches (wren, long-tailed tit) or suspended from thin tree branches (remez tit, many tropical weavers, etc.).
Woodpeckers hollow out hollows, on the bottom of which they lay eggs without any litter. Woodpecker and natural hollows are occupied by many birds that nest at the bottom: some ducks, pigeons, owls, swifts, various passerines. Male rhinoceros birds cover the entrance to the hollow with mud, leaving only a small hole through which they feed the incubating female. Many swallows build their nests out of lumps of mud, holding them together with sticky saliva. Salangana swifts build a nest only from saliva that quickly thickens in the air. Small trumpet-nosed, puffins and puffins, kingfishers, bee-eaters, sand martins and other birds dig holes up to 1-2 m long and even more; a nest is built at the end of the burrow or eggs are laid directly on the ground. In the steppes and deserts, wheatears, shelducks and shelducks nest in rodent burrows and cliff gullies. Few birds (coots, grebes, some terns) arrange floating nests from dry stems and algae, placing them in thickets of emersed vegetation.
The nest protects the masonry, incubating bird and hatchlings from enemies and adverse weather conditions. The protective qualities of the nest are the higher, the more skillfully it is built and the more inaccessible it is. So, in the Moscow region forests, where there are many people and livestock are pastured, up to 40-50% of nests located on the ground and low bushes perish, up to 20-30% of nests in trees and only 5-10% of nests in hollows. Frequent frightening of incubating birds increases the death of eggs and chicks, as it facilitates the detection of nests by various predators (ravens, magpies, cats, etc.). Nests significantly improve the conditions of incubation, because temperature fluctuations in them are much less than in the external environment.
Almost all birds incubate eggs, i.e. they heat them. Only weed chickens do not incubate clutches - Megapodiidae: the heat necessary for the development of the embryo is formed during the decay of plant rags of a voluminous "nest". Only females incubate polygamous; in monogamous both partners take part in incubation, replacing each other on the nest (gulls, many passerines, etc.), or only the female incubates, and the male feeds her and protects the nest area (owls and diurnal predators, some passerines). In incubating birds, feathers and fluff fall out on the abdomen and a nest spot is formed - a patch of bare skin with highly developed blood vessels, with which the bird presses against the eggs. There are 2-3 mosquito spots or one large one. The heat-insulating qualities of the nest and the presence of brood spots ensure good warming of the eggs: the laying temperature reaches 36-38 ° C. Anseriformes do not form brood spots, but the absence is compensated by the abundant downy lining of the nest. Emperor penguins nesting on the ice of Antarctica hold their only egg on their paws, covering it from above with a fold of belly skin; at an air temperature of -5-10 ° C, the temperature inside the egg is + 36-37 ° C.
Most birds begin intensive incubation after all the eggs have been laid, and therefore the hatching of the chicks takes place more or less simultaneously. In diurnal predators, owls and some other birds, incubation begins after the laying of the first egg. Accordingly, hatching of chicks proceeds gradually and, with large clutches, stretches for 5-10 days. Length of incubation period depends on the size of the egg and bird, the type of nest and the intensity of incubation. Small passerines incubate for 11-14 days, a crow - 17, a raven - 19-21, a teal cracker - 21-24, a mallard - 26, swans 35-40 days, etc. The largest duration of incubation - about two months - in large penguins , albatrosses, vultures.
References: Naumov N.P., Kartashev N.N. Vertebrate Zoology. - Part 2. - Reptiles, birds, mammals: A textbook for biologist. specialist. Univ. - M.: Higher. school, 1979. - 272 p., ill.
The reproductive system of birds is characterized by the fact that the period of its activity in the vast majority of species is limited to a strictly defined time in the year, and at rest the size of the gonads is literally tens of times smaller than during the period of activity.
In the structure of the reproductive system of females, its asymmetry is characteristic: the right ovary, as a rule, is absent, the right oviduct is always absent. During the breeding season, the volume of the ovary increases greatly, and since the eggs in it are at different stages of development, the entire organ takes on a kind of grape-like shape. At the end of the laying of eggs, the ovary rapidly decreases, and its size reaches the size of the ovary of the dormant period even at the time when the bird is incubating. In the same way, in connection with the onset of the breeding season, the oviduct also increases in volume. For example, in a domestic chicken, the oviduct during the dormant period is about 180 mm long and 1.5 mm in the lumen, during the laying period - about 800 mm in length and about 10 mm in the lumen. All departments of the oviduct at this time become more isolated than at other times of the year.
After the laying period, the oviduct collapses, the tubules of its glands are reduced, its lumen remains uneven and expanded in places. In a bird that did not lay eggs, the oviduct has the appearance of a smooth and thin tubule throughout its entire length.
These differences in the condition of the oviduct can serve as a reliable sign in determining the age of autumn and spring birds. A very characteristic adaptation to the rearing of offspring in birds is the development of so-called brooding (hatching) spots. The presence of these spots facilitates the heating of the masonry. The skin in the area of the sores is characterized by a special looseness of the connective tissue; the fat layer here usually disappears; down, and sometimes feathers and their rudiments fall out; skin muscle fibers are reduced; at the same time, the supply of these places with blood is enhanced. A fully developed brood spot is a patch of bare and slightly inflamed skin.
Each species of birds is characterized by a certain arrangement of perched spots; they are sometimes paired, sometimes unpaired. Passerines, petrels, guillemots have one spot, pheasants, waders, gulls, predators have two abdominal and one chest. The size of the nest spots is in a certain correspondence with the size of the masonry. Geese and ducks do not have mosquito spots; they, however, during the period of laying eggs develop a special long fluff, which is pulled out by the bird; with this down the incubating bird surrounds the eggs in the nest, and it serves as an excellent means of protecting them from cooling. Gannets do not have brood spots, but they warm the eggs by covering them from above with their webbed paws; guillemots and penguins put their paws under the eggs. These birds, apparently, have special arteriovenous anastomoses in their paws, which provide enhanced blood supply to these parts of the body. In addition, penguins have a special leathery protrusion, or pocket, near the cloaca, which is arbitrarily stretchable and allows the incubating bird to cover the egg with skin. In addition to the changes just mentioned in the body of birds in connection with the breeding season, there are others, in particular, in many species a bright breeding outfit develops.
The difference in appearance between males and females is referred to as sexual dimorphism. The external signs of sexual dimorphism cannot fit into any general scheme. Penguins, petrels, copepods, grebes, loons, wrynecks, swifts, many bee-eaters and kingfishers do not differ between the sexes either in color or in size. Males and females of small passerines, most birds of prey, owls, waders, gulls, guillemots, shepherds and other birds differ only in size. In other species, males differ more or less sharply from females in coloration. Usually the color of the male is brighter in those species in which the male does not take part in caring for the offspring. In these cases (ducks, many chickens), females often have a pronounced protective coloration. In those species in which males take care of the offspring (colored snipes, waders, some kingfishers, three-fingered, etc.), females are somewhat brighter than males. Differences in color usually appear after reaching puberty, but sometimes even earlier (woodpeckers, passerines, etc.).
In many forms that have two molts per year, color dimorphism is noticeable only at certain times of the year, namely during the breeding season. The brightness of the color of males is especially characteristic of northern ducks (but not geese), many chickens (pheasants, francolins, capercaillie, black grouse), many passerines (the so-called birds of paradise, orioles, finches, redstarts, etc.). In related groups, the differences in coloration of the sexes, in general, are similar even in different species (in orioles, males are bright yellow or red, females are dull greenish with a longitudinally mottled ventral side of the body; in many finches, males have red colors that are absent in females, for example, in schurs, crossbills, bullfinches, especially in lentils, etc.).
Sometimes females develop a color similar to that of males (the so-called cock-feather color in grouse, in some passerines - redstarts, zhulans, etc.). In addition, with age, in females with functioning gonads, the appearance of features similar to the color of the male is sometimes observed; this happens, for example, in birds of prey (merlins, etc.). Sexual differences in coloration are expressed not only in the color of plumage, but also in the color of other parts of the body (beak, iris, bare parts of the skin, even the tongue). In cuckoos, the color of males is of the same type (gray), females are dimorphic (in addition to gray color, there is also a red one).
Sex differences are expressed, in addition, in the presence of outgrowths and appendages of the skin on the head (for example, in chickens), in the development of individual feathers (Khokhols, long tail coverts in peacocks, feathers on the wing and tail of birds of paradise, long tail feathers in pheasants and etc.), in the proportions, sizes and shape of individual parts of the body, in the arrangement of internal organs (the voice apparatus of many species, the throat sac of the male bustard, etc.), in the total value. Males of gallinaceous birds develop spurs on their legs; males and females of many species have different beak sizes (for hornbills, ducks, scourges, some passerines, etc.). As a rule, males are larger than females. This is especially pronounced in chickens and bustards. Other groups have more females than males. This is observed in those species in which males take care of the offspring (in phalaropes, colored snipes from waders, three-fingered, tinamous, some cuckoos, kiwi and cassowaries). A large size of females, however, is also found in those species in which the main part of the care for the offspring lies with the females (in most diurnal predators, owls, many waders).
With the onset of spring, when revival begins everywhere in nature, the behavior of birds also changes. Migratory species leave their winter quarters and go to their distant homeland. Nomadic non-migratory birds also begin to approach their nesting sites. Sedentary species appear at nests. Not in all places and not in all species of birds this spring revival occurs simultaneously. The further south the territory is, the earlier, of course, the spring revival of nature occurs there. For each bird species, the spring revival is associated with the onset of special, favorable circumstances for this species. Sometimes, it seems even difficult to understand why one bird arrives early to the nesting site, and the other late.
The bearded vulture, or lamb, living high in the mountains, begins to nest in the Caucasus and Central Asia as early as February, when everything around is covered with snow; such an early start of nesting is explained by the slow development of chicks. They appear in April, by July they only reach the size of adults, and until September they still remain with their parents and use their help. Consequently, the first months of the life of young bearded vultures fall at the most favorable time in terms of temperature, nutritional conditions, etc.: n. If bearded vultures began nesting later, then the rearing of chicks would end only in winter. For the same reasons, the gyrfalcons nesting in our far north sit on their eggs in the snow in early spring, otherwise they would not have had time to hatch the young before the onset of severe autumn weather. The desert saxaul jay starts nesting in the Karakum desert very early, even before the appearance of a large number of insects and before the development of vegetation. This early date gives the desert jay an opportunity to bring out its young in relative safety. Its nest is easily accessible to the main enemies of the birds of the Central Asian deserts - various snakes and monitor lizards, but early nesting allows the jay chicks to learn to fly before the revival of reptile activity begins with the onset of heat.
The last example is the swift and the swallow. Both birds are excellent fliers and feed on insects, but the swift arrives late and leaves early, and the swallow stays with us much longer. The late arrival of the swift is explained by the fact that favorable conditions for feeding and rearing chicks for it come later than for the swallow. The difference in the device of the eyes allows the swallow to see well both in front of itself and on the sides, while the swift sees well only in front of itself. Therefore, the swift can only catch flying insects, and the swallow, in addition, can peck out or grab on the fly those insects that sit on buildings, trees, etc. The mass years of insects fall on the warmest time, while sitting insects in large numbers can be found earlier and later. That is why the swift appears with us later than the swallow and flies away earlier.
Many birds form pairs for life; this includes large predators, owls, herons, storks, etc. Others form seasonal pairs (songbirds). There are, however, also such species which do not form pairs at all and in which all care for the offspring falls to the lot of sex alone. Most often, this sex is the female. This is how the summer life goes on for most of our chicken birds - capercaillie, black grouse, pheasant, as well as for the turukhtan sandpiper. However, in the phalaropes living in the north and in the three-fingered waders found in the Far East, the male takes care of the brood. In the mentioned chicks and turukhtans, the males are brighter; than females. The opposite is true for phalaropes and three-fingered birds: in them, the female is taller and more elegantly feathered than the male. Birds that form pairs are called monogamous, those that do not form pairs are called polygamous.
The behavior of birds during the mating season, which, as a rule, (in the spring months and early summer) differs in a number of features. Many birds also change their appearance at this time. A number of birds change part of their plumage by spring and put on a mating outfit, usually different from autumn bright colors. In some species, the males lek, that is, they take special, conspicuous poses from a distance, make special cries. Such lekking is especially well expressed in chicken birds - black grouse, capercaillie, white partridge, and some waders. Other birds do this in the spring peculiar movements in the air - soar high up, fall down, soar again, uttering loud cries at the same time. Such a mating flight is performed, for example, by birds of prey; the spring draft of woodcocks and the spring "bleating" of snipes have the same meaning. males sing birds during the mating season, enlivening with their singing both inhospitable deserts, and harsh tundras, and human settlements.The same phenomena include spring "dances" cranes, and cuckoos chirping, and woodpeckers' spring drumming, and pigeons cooing. Each species of bird is characterized by a specific behavior that is different from other species in the spring - voice, posture, etc.
Each songbird - nightingale, starling, chaffinch - sings in its own way. Showing thus refers only to other individuals of the same species and serves as a certain signal for them. These signals are by no means always directed to individuals of the opposite sex. For a long time it was thought that the singing of male birds refers only to females and attracts them. In fact, this is not so. The meaning of singing is primarily to show other males of the same species and possible competitors that the nesting territory is occupied. Birds in the spring, as you know, jealously guard the places they occupy (nesting sites) and expel all other individuals of the same species from them. The nesting site is especially zealously protected during the most "responsible" periods, immediately before laying eggs in the nest and during incubation. Interesting observations were made in England. A weasel appeared near the nest of the reed bunting. The male and female bunting began to fly around her screaming and tried to drive her away. Another reed bunting flew up to the noise, and the disturbed couple, leaving their caress, began to chase the bunting. This scene was repeated three times in a row. The value of displaying also lies in the fact that it expresses and enhances the excitation of the displaying bird and individuals of the opposite sex. This is the only meaning of mating in those species that do not form mating pairs (grouse, black grouse, turukhtans). The center of the nesting site of a bird is the nest - the place where the female lays her eggs.
However, not all birds build nests for themselves. In the north, for example, on the islands, in the White Sea, on Novaya Zemlya, as well as on the Chukotka Peninsula, on Kamchatka, on the Commander Islands, seabirds (guillemots, guillemots, auks) nest in huge numbers, forming clusters of many thousands, the so-called "bird markets ". But they do not actually make nests, and each female lays her egg right on the rock ledge. The Nightjar and the Avdotka do not make nests: they lay their eggs directly on the ground. Some birds only clear a place for laying and sometimes even make a simple bedding of dry grass, moss, feathers, etc. Pheasants, wood grouses, hazel grouses, white partridges, black grouse, waders, most owls, some predators, as well as those birds that breed chicks in hollows are woodpeckers, vertices.
Most birds, however, build nests, with each species having a specific nesting style and choice of materials for its construction. Young birds, who have never seen how a nest is built, arrange it in the same way as their parents. Most often, nests are made of branches, grass or moss; these nests are either folded or woven, and special additional materials are often used to fasten them and lining them. Thrushes weave a nest of stems and coat it with clay. The finch makes a nest of moss, masking it with lichen. The Remez tit skillfully weaves a nest of wool in the form of a purse with a long side corridor. Small birds nesting on the ground (larks, wagtails) build grass nests or line a depression in the ground with grass.
Birds of medium and large size build nests from large twigs and branches. Some birds have several nests, in one of which they nest, while others serve as spares. In large birds of prey (eagles, eagles), the nest serves for many years in a row and, as a result of amendments and add-ons, turns over the years into a huge structure up to 2 m in height and in diameter. Such nests, in the end, usually fall to the ground during storms, since the bitches that serve as their support cannot withstand their weight. The inside of the nest is usually deepened, and the edges are raised; the recessed part of the nest - a tray, or a tray, serves to place eggs and chicks.
Some birds make stucco nests. Flamingos make their nests out of silt in shallow water. Rocky nuthatches living in the mountains build their nests out of clay. The barn swallow builds a saucer-shaped nest of clay and mud glued together with saliva under the roofs. The city swallow, or funnel, arranges a nest closed from above with a roof made of the same materials. Some birds nest in burrows. In kingfishers, a zigzag path breaks through between roots in earthen cliffs on the banks of rivers; this passage leads to a cave, the bottom of which is lined with fish scales. Sand martins nest in colonies along river banks. Their nests are difficult to access, as a narrow passage leads to them, sometimes reaching a length of 3 m.
Pink starlings, shelducks, rollers and bee-eaters nest in minks. Finally, the oystercatcher found along the sandbanks of rivers in Turkmenistan simply buries its eggs in the hot sand. This method of nesting is somewhat reminiscent of the actions of weed chickens, or big-footed ones, living in Australia and on the islands southeast of Asia. Weed chickens lay their eggs in huge heaps of sand or rotting plants, these heaps sometimes reach 1.5 m in height and 7-8 m in circumference. The eggs here are well protected from cooling, and the embryo's own heat is enough for its development. A place for building a nest in those birds that actively defend their nesting site, that is, in passerines, nightjars, some waders, etc., is found by the male, who, moreover, usually returns from wintering or migration earlier than the female. The number of eggs in a clutch for each bird species varies within certain limits. More or less of them depends on various reasons. In many species, in years that are favorable in terms of temperature, and especially in terms of nutrition, the number of eggs in the clutch is greater than in bad years. This has been established for many owls, gallinaceous owls, and others. In especially unfavorable years, such birds do not nest at all. The age of the bird is also of some importance.
In predators, ravens, old females apparently lay fewer eggs than young ones. In chickens, on the contrary: in the first year, females lay fewer eggs; fewer eggs are laid by young females of some passerines, such as starlings. Due to different nesting conditions in the same species of birds, the number of eggs in the clutch in the north and in the temperate zone is greater than in the south. For example, in an ordinary wheatear in Greenland, the number of eggs in a clutch is 7-8, in the European part of our country - 6, and in the Sahara - 5.
A large number of eggs in a clutch in the north is, as it were, insurance against adverse climatic conditions, and also corresponds to the large opportunities for rearing chicks in the north (long day and almost round-the-clock activity of insects). Always one egg in a clutch occurs in some predators (for example, in the short-toed eagle), in the oystercatcher, in the tube-nosed, and in many guillemots. Nightjars, pigeons, cranes, flamingos, pelicans, gulls, terns have 2 eggs in a clutch. In waders and quails, the usual and maximum number of eggs in a clutch is 4. In small passerines, the number of eggs in a clutch is 5, often 4, 6, and 7; it happens even more, for example, in the great tit up to 15, in the long-tailed tit up to 16. Of the ducks, the largest number of eggs in the teal is 16, of the chickens in the gray partridge - 25. The usual number of eggs in a clutch of chickens and ducks is 8-10.
In the spring, males are overgrown with bright outfits, bring out inviting trills and roulades, dance pirouettes, and fight with rivals. And all this in order to attract the attention of the female and continue their race. The criteria for choosing a partner for all birds are different: it can be the strongest, the most colorful, loud, caring or the most hardworking. Relationships in bird pairs can be either short-lived or long-term, sometimes for several seasons, sometimes for a lifetime.
Birds, like other land animals, are characterized by internal fertilization. The male injects sperm into the female's genital opening, the sperm cells reach the mature eggs inside the ovaries and fertilize them.
Interestingly, birds have paired genitals and genital tracts, but in most species, only the left "halves" are used for reproduction. It is possible that the simultaneous formation of large eggs in paired ovaries is simply impossible. As for the males, outside the mating season they are usually sterile, but in the spring their testes can increase in volume by almost a thousand times.
The male's sperm enters the female's genital opening at the bottom of the oviduct system. From there, it moves into the oviduct, where in some cases it can remain for several weeks before being used to fertilize the egg. Fertilization occurs directly in the initial part of the oviduct.
After that, the egg moves towards the cloaca, "overgrowing" with membranes, and, finally, in the thickened posterior section (uterus), just before flowing into the cloaca, a calcareous shell-protection is formed.
How is mating going?
Birds do not have a special genital opening, their genital tract goes into the cloaca - the final section of the digestive system of birds. Mating itself consists in the fact that the male presses the outlet of his cloaca to the outlet of the female's cloaca (the so-called cloacal kiss) and transfers his sperm to her.
Only in a few species, in particular ostriches and some ducks and geese, males have a special copulatory organ in the form of an unpaired eversible section of the cloacal wall, which enters the female genital opening during mating.
In males of the Argentine duck, this organ can be one and a half times the length of the duck itself, reaching 45 cm. A reasonable question arises: where so much? Doesn't it wrap itself in a ball in the female's body during mating? That's right, it doesn't roll. And from a "technical" point of view, the size of the reproductive organ of these amazing birds is completely redundant. And they grew it for themselves for boasting.
Other animals, including humans, use symbols to get around rivals in mating games: a peacock fluffs its tail, a dove puffs up to appear bigger, a dolphin dances, and a man begins to shower gifts on the lady of the heart. The Argentine uts "decided" to simplify the scheme, using the penis itself as a symbol of the penis. Looking at the proposed assortment of genitals during mating games, the female chooses the most suitable partner for herself!
Of all the representatives of the fauna in birds, the most difficult process of courtship and mating is the so-called mating games.
In the spring, males are overgrown with bright outfits, bring out inviting trills and roulades, dance pirouettes, and fight with rivals.
And all this in order to attract the attention of the female and continue their race.
The criteria for choosing a partner for all birds are different: it can be the strongest, the most colorful, loud, caring or the most hardworking. Relationships in bird pairs can be either short-lived or long-term, sometimes for several seasons, sometimes for a lifetime.
Birds, like other land animals, are characterized by internal fertilization. The male injects sperm into the female's genital opening, the sperm cells reach the mature eggs inside the ovaries and fertilize them.
Interestingly, birds have paired genitals and genital tracts, but in most species, only the left "halves" are used for reproduction. It is possible that the simultaneous formation of large eggs in paired ovaries is simply impossible. As for the males, outside the mating season they are usually sterile, but in the spring their testes can increase in volume by almost a thousand times.
The male's sperm enters the female's genital opening at the bottom of the oviduct system. From there, it moves into the oviduct, where in some cases it can remain for several weeks before being used to fertilize the egg. Fertilization occurs directly in the initial part of the oviduct.
After that, the egg moves towards the cloaca, "overgrowing" with membranes, and, finally, in the thickened posterior section (uterus), just before flowing into the cloaca, a calcareous shell-protection is formed.
How is mating going?
Birds do not have a special genital opening, their genital tract goes into the cloaca - the final section of the digestive system of birds. Mating itself consists in the fact that the male presses the outlet of his cloaca to the outlet of the female's cloaca (the so-called cloacal kiss) and transfers his sperm to her.
Only in a few species, in particular ostriches and some ducks and geese, males have a special copulatory organ in the form of an unpaired eversible section of the cloacal wall, which enters the female genital opening during mating.
In males of the Argentine duck, this organ can be one and a half times the length of the duck itself, reaching 45 cm. A reasonable question arises: where so much? Doesn't it wrap itself in a ball in the female's body during mating? That's right, it doesn't roll. And from a "technical" point of view, the size of the reproductive organ of these amazing birds is completely redundant. And they grew it for themselves for boasting.
Other animals, including humans, use symbols to get around rivals in mating games: a peacock fluffs its tail, a dove puffs up to appear bigger, a dolphin dances, and a man begins to shower gifts on the lady of the heart.
The Argentine uts "decided" to simplify the scheme, using the penis itself as a symbol of the penis. Looking at the proposed assortment of genitals during mating games, the female chooses the most suitable partner for herself - and voila!