Sense organs in birds. Birds have well-developed tactile, temperature, pain sensitivity and hearing. They perceive sounds with an oscillation frequency of 200 to 20,000 Hz per second (the absolute thresholds for chickens are in the range of 90-9000 Hz), the sound intensity should not exceed 70-85 dB, although they can adapt to sound intensity up to 90 dB ( stronger sounds negatively affect the state of the central nervous system and productivity).
Sound alarm. Chickens have described 25 sounds that they make “when communicating.” This is more than that of cats and piglets. Only seven varieties of danger signals were found.
It has been established that chicken embryos communicate with each other by “tapping”, making clicking sounds. Following the example of the leader who was the first to make a sound, his brothers also begin to try their voice and switch to pulmonary breathing, which accelerates their growth and formation. Sound signaling during the embryonic development of birds ensures the synchronization of the hatching of chicks from eggs, allowing them to leave the shell together and, in the wild, the whole family quickly leave the nest, avoiding encounters with predators. For better synchronization of chick hatching, the incubator is sounded using a radio-electronic device. The device is turned on on the 17th day of egg incubation. It broadcasts clicking sounds recorded from embryos, which makes it possible to reduce the hatching of chicks from a batch of eggs obtained from different layers to one day. The additional connection of an imitation of the voice of a hen calling the chicks speeds up their exit from the trays and the desire to move to the call of “mother” - “follow me”.
The organs of vision in most species of poultry (pigeon, goose, duck, turkey) play an important role and are therefore relatively well developed. The structure of the eye is somewhat different from the structure of the eye of mammals. Thus, the eyeball of a bird is not spherical in shape, but is flattened in front and behind, while in ducks it has a conical shape. The cornea is most convex in predators, least convex in waterfowl. The cornea and bone plates do not allow the eyeball to deform under air pressure during flight, under water pressure when immersed in it, or under the action of the oculomotor muscles.
The bird's eye is distinguished by unusually fast and accurate accommodation, especially developed in predators. Accommodation is carried out not only by changing the curvature of the lens, but also by changing the shape of the cornea. The next feature of the eye is the ridge. This is an irregular quadrangular plate located in the thickness of the vitreous body at the entry point of the optic nerve. The ridge is credited with the function of nourishing the vitreous body and retina. It is also assumed that the ridge regulates intraocular pressure (which changes during rapid accommodation) and serves as an auxiliary device for observing moving objects. It is also credited with the function of heating the eyeball, which is important mainly for birds flying at high altitudes. In birds, like in mammals, there is a layer of cones in the visual part of the retina (there are especially many of them in diurnal birds). Cones provide visual acuity. They contain oily, colorless, blue, green, orange and reddish droplets that determine color perception. There is only one zone of best vision in the retina of mammals, but in birds there may be two or three of these zones. This is due to the nature of the location of the eyes, which in most birds face in opposite directions. This arrangement of the eyes limits the area of binocular vision to a very small area at the level of the continuation of the beak, where the visual field of the left and right eyes overlaps. The visual field of each eye produces a predominantly flat image. It is very large: birds can see objects behind them. Pigeons have a visual angle of 160° in each eye. The bird compensates for the lack of three-dimensional (binocular) vision by changing the position of its eyes when turning its head. Birds have a well-developed third eyelid - a nictitating membrane, which is usually located in the inner corner of the eye, but can cover the entire visible part of the eyeball.
Different species of birds have different visual acuity. Geese recognize individuals of their species at a distance of up to 120 m, ducks - up to 70-80 m. In order to peck at the grain again, the chicken must increase the distance between the grain and the eye by at least 4 cm. When choosing food, birds of all types pay attention primarily to the size of its particles. They have an innate sense of proportion regarding the size of the particle, which they can easily swallow. This measure changes with age in proportion to the increase in the size of the esophagus and beak. The shape of the chicken feed particles is not important. Only during their life do they learn to recognize the shape of food objects.
Hearing. Birds do not have an external ear; instead, most species have a fold of skin or a tuft of thin feathers surrounding the entrance to the external auditory canal. In waterfowl, the feathers at the entrance to the external auditory canal are arranged in such a way that they completely cover it while they are under water. The external auditory canal is short, wide and covered by the eardrum. The connective tissue membrane does not have its own bone base, but is attached directly to the cranial bone. Sound waves are perceived by the eardrum and transmitted in the form of vibrations through the column (the only auditory ossicle) to the perilymph and endolymph of the inner ear. The inner ear consists of a bony canal and membranous labyrinths located inside it, divided into an organ of hearing and an organ of balance. The organ of hearing is formed by the cochlea, the organ of balance is formed by the vestibule and semicircular canals.
The bird's hearing is very well developed. Birds of prey can hear the squeak of a mouse even at a distance of 60 m. Of domestic birds, the best-developed hearing is in chickens, whose ancestors lived in virgin forests, where in dense bushes good hearing was a better means of defense than acute vision. The good development of hearing in chickens is also evidenced by the fact that the chick in the egg, already a day before hatching, reacts to changes in the external environment with a frightened squeak, but subsides when the hen calms it with deep clucking. Immediately after hatching, chicks can hear their mother in the dark at a distance of up to 15 m. By their characteristic clucking, they individually recognize their mother and run to her, not paying attention to other hens sitting near her. Hens can also recognize their chicks by squeaking at the same distance, even if there are other sources of noise around them even within a radius of 1 m. The mother's voice attracts chicks more effectively than her appearance, even at a distance of about 50 m to the sound source. The chicks recognize a familiar hen house distributing food only from a distance of 25 m. If sounds come from above, in front and behind, then chicks and adult birds do not recognize is able to determine the direction of sound sources, since sound waves arrive from these sources from the same distance.
If a chick has lost its brood, it makes shrill, plaintive sounds, to which the hen responds with increased frequent clucking. The chicken determines her location by quickly running in different directions and listening to the hen's signal from different points. It determines the correct direction when sound waves are perceived sequentially by the right and left ears. The absence of the auricle, which improves the location of sounds, is apparently compensated by the high flexibility and mobility of the neck, which allows the head to be quickly turned in different directions.
Everyone is familiar with the cries of birds that serve as alarm signals; They were recorded and even managed to be used to protect crops from crows and fisheries from seagulls. The sentinels, with their shouts, even announce what kind of enemy is approaching and they must wait for him from the ground or from the air. After the signal, all the birds freeze motionless and remain silent, especially the chicks, which immediately stop squeaking. Cubs, feeling hunger or fear, scream with all their might, and sometimes (usually chickens and ducklings) make a sound that seems to express pleasure. Everyone knows the calling cry of a chicken. With its help, you can call the chickens to the speaker through which it is broadcast; therefore, it is not necessary for the chickens to see the hen. In the same way, a mother can be attracted by the calling sound of a chick; but put a chicken under a soundproof glass cover - and the chicken, seeing it perfectly, will pass by indifferently.
Skin feeling in birds it is carried out mainly by tactile bodies located on the non-feathered parts of the body, especially in the cere of the beak. However, sensitive nerve endings penetrate into the skin of other parts of the body, closely adjacent to the epithelial cells. They also contribute to the perception of heat and pain. Much more often in birds there are organs of touch that lie under the epidermis of connective tissue (Herbst bodies), under large feathers (tail and flight feathers), as well as in the skin of the paws and thighs. They are credited with the ability to respond to changes in pressure. Large bodies of this type, embedded in the mucous membrane of the tongue and along the edges of the beak, make it possible to determine the size, shape, texture and degree of hardness of food objects.
Birds constantly take care of their feathers. This is especially important for waterfowl, which ensure the non-wetting of the feather by lubricating it with the secretion of the coccygeal glands.
Composition and properties of the secretion of the coccygeal gland. Upon visual examination, the secretion of the coccygeal gland can be characterized as a thick, light yellow liquid with a faint odor of goose fat. A biochemical study revealed that the dry matter content in the secretion of the coccygeal gland is 37.30-44.2%. The secretion reaction is slightly alkaline. Most of the secretion consists of lipids. The secretion of the coccygeal gland contains a number of minerals. It is interesting that the amount of some components of the secretion differs between drakes and ducks. For example, the total protein content of ducks is 16.9 mg/g higher, and the sodium content is 0.97 mg/g higher than that of drakes.
It was found that when cultivating Staphylococcus aureus and Escherichia coli on agar, a clearing zone of 15 mm for Escherichia coli and 10 mm for Staphylococcus aureus is formed in the area of application of discs moistened with the secretion of the coccygeal gland. This confirms the bacteriostatic properties of the coccygeal gland secretion both in relation to gram-positive and gram-negative microflora. The relative mass of the coccygeal glands depends not only on age and nutrition, but also on the intensity of the ducks’ contact with water. With prolonged restriction of access to water for bathing, the relative weight of the coccygeal glands in Peking ducks decreases by 0.02-0.03% of body weight. Extirpation of the coccygeal glands in Peking ducks, both at an early age and in adults, does not cause wasting and rickets. After extirpation of the coccygeal glands in Peking ducks, there are no changes in the number of erythrocytes, leukocytes, blood volume, hemoglobin concentration, hematocrit value, or acid capacity of the blood. Extirpation of the coccygeal glands in Pekin ducks entails significantly pronounced changes in the concentration of proteins, lipids, glucose, and inorganic phosphate in the blood.
The taste organs of birds are poorly developed. The organs that perceive taste stimuli are either barrel-shaped structures (like the taste buds of mammals) or low, highly elongated structures equipped with a relatively thick layer of supporting cells (as, for example, in lamellar beaks). The tongue and hard palate are covered with a thick stratum corneum, in which taste buds can hardly be located. Taste corpuscles are located in the root of the tongue on its sides and at the bottom of the oral cavity, in the soft palate and near the larynx. Birds of all species distinguish between salty, sour, bitter and sweet, and sensitivity to bitter is only slightly developed in poultry. Waterfowl, however, reject bitter solutions in concentrations that are unpleasant to humans. Sensitivity to sweets is also poorly developed in birds. Malt and milk sugar have virtually no taste for birds, and they perceive synthetic sweet substances, such as saccharin, as sour rather than sweet. The taste of glycerin, which humans evaluate as sweet, is also perceived by birds, and the same can be said for weak salty-bitter solutions. However, the question remains whether these substances taste sweet or bitter to birds. Sensitivity to bitter in all bird species is similar to that in humans. For chickens, taste plays a very small role when choosing food. Although chickens prefer certain foods over others, they are guided by visual or tactile perception.
The olfactory organs of birds are very poorly developed. Goblet-shaped sensory cells, dotted with very short hairs, are located in the epithelium of the mucous membrane of the nasal cavity, lining the dorsal concha and septum. The bird has no odor-perceiving structures at all. In numerous experiments, it was never possible to teach a pigeon to distinguish the smell of anise and rose oils. The weak development of the bird's sense of smell is also evidenced by the fact that laying hens drink slurry. The smell of spoiled eggs does not bother them, and they often peck at strong-smelling substances such as droppings, compost, etc.
The bird's memory is poorly developed. It depends on the type of bird, age, duration and intensity of the stimuli and many other factors. It takes about 100 repetitions to train a chicken to peck the larger of two kernels of corn. To regain a skill after a seven-month break, 24 repetitions are required, and after another four-month break, 15 repetitions are required. Adult chickens, if they are not allowed to roam for two weeks, no longer remember that attractive-looking sorrel is almost inedible for them. On the other hand, chickens for many months prefer corn kernels if they have had it for at least two days and have had to learn to peck at it, despite the large size of the grains. The bird remembers familiar places very poorly. Chickens remember the placement of the feeders where they received their favorite food for three weeks; For chickens, this time is shorter - until 10 weeks of age, chickens, as a rule, do not remember their favorite place on the run. They quickly find other similar places and forget them just as quickly. The pullets remember their previous housing or run for about three weeks, and after four weeks they treat them as strangers. An adult chicken finds its place in its previous environment after 30 days, after 50 days it does this with difficulty, and after 60 days everything here is new to it.
The duration of the period after which members of the flock still recognize a temporarily removed individual after its return was studied. It turned out that if young cockerels that grew up together in a herd with an established social hierarchy are returned there after their two-week absence, then the members of the group perceive these individuals as strangers, since the social order in the herd has changed during this time. The period of adaptation of adult birds to each other is on average 3-4 weeks. The duration of the habituation period depends on the breed, physique, social status and individual characteristics of the individual. Roosters of light breeds renew their relationship with a fight within 14 days, while roosters of heavy breeds require a month or more for this. It is not surprising that the rooster does not forget his defeat even after six months, especially in cases where he was persecuted by a despotic individual.
Group behavior. All poultry species are social, with each individual's behavior influenced by its relationships with other members of the flock. In ducks, at the end of winter, the sexual instinct increases, which entails a spring increase in pugnacity among both drakes and ducks. Weak individuals submit to stronger ones after repeated defeats. After this, all individuals are guided in their relationships by newly emerged social connections. Towards the end of the mating season, this order fades away, and the ducks rarely interact with each other. The superiority of stronger individuals does not remain strong due to the frequent resistance of subordinates. Therefore, individuals that dominate mainly during feeding and mating can often change.
Among geese, the leader of the herd is the gander; all other individuals obey him. He and other high-ranking individuals provide themselves with certain advantages when obtaining food and in conflicts with other herds. The social unit is the family, where in natural conditions goslings usually grow up under the supervision of their parents. Upon reaching sexual maturity, new hierarchical connections are formed between the goslings. High-ranking individuals use their superiority not only when feeding, but also in all other cases when subordinate individuals try to counteract them.
A flock of birds is not an unorganized aggregation of individuals whose behavior is determined by random circumstances. There is a strict hierarchy here. The entire group obeys the leader. An individual is considered dominant if it is more aggressive than others in the group and enjoys advantages in reproduction, feeding and movement.
When we counted the beak blows that young cockerels reward each other, we found out that among them there is an “alpha” who pecks everyone, while no one dares to touch him, and an “omega” who is pecked by everyone and sometimes pecked to death - he doesn’t even tries to defend himself. The first three days after hatching from an egg, any moving object puts the chick to flight: it hurries to take refuge under its mother’s wing. A week passes, the chickens begin to rush around the poultry yard in all directions, spreading their wings; from the second week, something like battles arise between them: two chicks jump at each other exactly like adult roosters, but they do not yet use their beaks.
Between the fifth and sixth weeks, the fights become more serious, the opponents are already using their beaks, although not too hard; one of the fighters may retreat, then returns and hits the enemy again with its beak.
Fights, during which relationships of dominance and submission are established, begin later. At exactly what age it is difficult to determine: it depends to some extent on external conditions, on the characteristics of the group, etc.
Apparently, chickens recognize birds of their own breed - in Leghorns this ability manifests itself at ten days of age. Hens are much less aggressive than cockerels, which also attack females; however, by the time they reach puberty, roosters stop attacking chickens.
Chickens also establish a special hierarchy, and a certain order is finally formed in them by the ninth week, while in males by the seventh. This order is not so immutable; Changes are possible due to the fact that not all individuals develop at the same pace. Such changes can be regulated by temporarily isolating individual birds, and they are given the opportunity to recover from beak blows.
Chickens can be isolated from the day of birth, and re-joined to the group only after the control individuals growing in the group have already established order in themselves.
Bettas are another matter: when they are brought together after being kept in isolation, they quickly establish a new order, thus proving that they do not have to live together from an early age. Isolated cockerels, after being united, turn out to be even more aggressive than those raised in a group.
It is interesting that the introduction of male sex hormones to young cockerels almost does not change the established relationships of submission and dominance, while with the introduction of female hormones they apparently become more “phlegmatic” - they avoid fights and do not strive to respond to blows with their beaks. Similar results were obtained in chickens: those of them that receive male hormones “increase in rank” somewhat (however, the difference from control birds is very small); the female hormone acts much more strongly, significantly reducing the “rank” of the individual. After order has finally been established in the group of young chickens, some of them can be transferred to another group, and then after a few days returned back to the first. The same individuals in different groups can stand at different levels of the hierarchy.
Particularly strong relationships of superiority and subordination are found in chickens. Here, each individual has its own specific place and recognizes it without resistance (unlike what we see in ducks and pigeons). How relationships are formed in a flock can be judged based on observations of the behavior of growing chickens. In the first days after being transferred to the poultry house, one can observe manifestations of the social instinct in the chickens: they run among other chickens and seek their company. Moreover, their behavior is not connected with the behavior of their partners: each chicken does everything on its own. Only when he notices that he is left alone does he begin to squeak pitifully, looking for partners or a hen. Chickens are indifferent towards strangers as long as there are no too sharp age differences between them. At the age of 2-3 weeks, the older ones begin to peck the younger ones in the head, tail, etc.
A tendency towards the formation of social ranking occurs in chicks at the age of 2-3 weeks, when fights begin to arise between them, still in the form of a game. These encounters, which involve both cockerels and hens, give them the opportunity to get to know and appreciate each other. After a short time, such tests of strength stop and a free union is formed, which exists until puberty.
With the onset of puberty, new, more serious, often bloody fights for dominance begin, the consequence of which (at the age of 8-10 weeks) is the emergence of a social hierarchy. This is a very strong order, which allows individuals of higher ranks to drive away low-ranking birds from feeders, drinking bowls, nests, peck them, etc. or prevent low-ranking cockerels from mating. Once a social hierarchy has been established, the herd usually reduces the number of attacks with which individuals previously sought to strengthen their position. This period of hierarchy formation lasts 2-3 weeks in newly formed communities or flocks.
As long as the number of chickens raised together remains within natural limits (50-100 in a group), the birds are able to individually recognize each other, and the social position of each is completely regulated. Among roosters, social ranking is more pronounced than among hens. If the stronger hen is usually satisfied with driving the lower one away from the food with a peck or a sharp movement, the rooster generally does not tolerate his opponent in his vicinity and expels him from the sphere of his activity with a radius of about 5 m.
Feeding behavior of birds. Birds' evaluation of food, i.e., the preference given to certain food over another, is a product of optical and tactile perception. This preference depends on the type of food offered and the time the bird has to eat it. Turkeys and chickens, when eating mealy feeds, need significantly more time to become satiated than when eating grains or pellets (turkeys, for example, need 16 minutes to saturate with pellets, and 136 minutes with mealy feeds).
The structure of the beak greatly influences the palatability of food. The small and pointed beak of chickens and pigeons is adapted for grasping relatively small, hard grains. Geese, with their hard and flat beaks, easily nibble grass and grab grains. The wide and long beak of ducks is adapted for capturing soft, wet food, consisting mainly of aquatic plants and animal organisms. Therefore, it is difficult for ducks to pick up individual small grains measuring 3-4 mm, while chickens and pigeons can peck grains of gravel measuring 0.5-1 mm. If given the opportunity to choose, they prefer grains measuring 1.5-2 mm. The optimal particle size of poultry feed is determined primarily by the size of the beak and the width of the esophagus.
For chickens and geese, these parameters are satisfied by wheat grains, for pigeons - hemp, and for ducks - corn.
The bird usually consumes granular feed of the appropriate size immediately; In the absence of feed with particles of the required size, preference is given to smaller particles. The bird must be accustomed to eating large grains, for which it usually needs to starve. If the bird overcomes the initial hostility, then subsequently it always chooses the largest grains from the food first. Only with the onset of saturation does she begin to eat more small grains, which are easier for her to swallow.
The state of the environment also plays a big role. As the ambient temperature rises, the palatability of feed quickly decreases. If at the same time the body temperature rises above 42°C, the chickens stop pecking at food, get worried and excitedly run from place to place. It is of interest to observe the rate of feed consumption with different methods of distribution in caged chickens. Cage batteries with a chain feeder in most cases turn on automatically at certain intervals. Chickens get so used to these intervals that just a few minutes before turning on the feeder they stick their heads out of the cage and rarely take the food in the feeder. As soon as the chain starts moving, all the chickens begin to peck at the same time, although before the chain was turned on, there was the same food in the feeder. Something similar happens when distributing feed with straddle loaders. Chickens begin to peck food mainly after the loader passes, even in cases when an empty cart passes, which does not supply any feed to the feeders.
The rate of feed intake also depends on whether the bird has free access to feed or whether this access is limited by time. Changing the form of feed (loose mixture, granules, grains) also caused its increased consumption if the bird got used to the new type of diet. So, when a bird that has been constantly receiving granulated food is replaced with granules with a loose mixture, the palatability of the latter decreases and increases again only after getting used to it (after a few days). When placing feeders and drinkers in the poultry house, it is necessary to remember the tendency of birds to form groups, for which it is necessary to provide areas measuring about 12-15 m. In order not to force chickens to leave their area, a feeder, drinker and nests for laying eggs are placed in it. Therefore, the distance between these points should not exceed 3-5 m.
Relations of social superiority are clearly manifested when there is a lack of feeding and watering fronts. Thus, interesting results were obtained from observations of laying hens placed on a slatted floor. To distribute the feed, two conveyor belts were used, which were turned on 4 times a day, and thus there was 7.62 cm of feeding front per hen. When distributing the wet mixture, the chickens crowded around the feeders, and here the strongest pushed aside the weaker, who later, after the strongest had been fed, did not, as a rule, dare to approach the feeders. With this feeding method, the average egg production over the last week was 2460 eggs. After the feeding frequency increased to 7 times a day, the chickens no longer crowded at the feeders, and weaker individuals also approached the feed. As a result, egg production gradually increased. After 3 weeks, when the feeding frequency was again reduced to 4 times a day, egg production began to decline, reaching a level below the initial level.
Along with habituation, feeding frequency is also important in cases where chickens do not have constant access to feed. When laying hens were fed with a chain feeder 6 times a day, the average monthly egg production was 22.8 eggs with a feed consumption of 122 g per head per day. Since a significant part of the feed was returned back to the bunker, the feeding frequency was reduced to 2 times a day. In this case, part of the feed was also returned to the bunker. However, the movement of the feed chain stimulated the birds to increase feed consumption, and the average feed consumption during the month was 103 g per head per day. Due to a decrease in feed consumption, egg production decreased to 19.4 eggs per month. With a repeated increase in feeding frequency, it increased to 21.9 eggs, which was accompanied by increased feed consumption.
Chickens and adult birds are characterized by a certain rhythm in feed consumption, which depends on the intensity of metabolism, the time of emptying of the crop and stomach. Chicks eat better with constant access to feeders; this creates equal opportunity for fast eaters and slow eaters. It is also important whether the chicks approach the feed alone or in groups. In an adult bird, under natural conditions, one can observe a special rhythm of alternating periods of increased activity and rest.
In pullets, the greatest activity is observed between 04:45 and 06:45, 10:45 and 12:45, 16:45 and 18:45 hours.
Hens older than 12 weeks significantly limit their activity and approach the feed less often than the drinkers. In their free time, they find perches and sleep on them.
After establishing a social hierarchy, hens of lower ranks remain on the roosts and begin searching for food later, when individuals of higher ranks return to the roosts.
2 Object of study, materials and equipment: 1. Chickens, goslings, ducklings, chickens of both sexes, geese and ducks. 2. Drawings and diagrams on the topic. 3. Ethogram forms, pen (pencil); camera, film or video camera, tape recorder; watch, device for measuring traffic intensity (pedometer), measuring and recording equipment for telemetry; a set of different types of grain and flour feed; areas in the poultry house with different air temperatures and different air speeds.
In general, the sense of smell in birds is very poorly developed. This correlates with the small size of their brain's olfactory lobes and short nasal cavities located between the nostrils and the oral cavity. An exception is the New Zealand kiwi, whose nostrils are located at the end of a long beak and the nasal cavities are elongated as a result. These features allow her to stick her beak into the soil and sniff out earthworms and other underground food. It is also believed that vultures find carrion using not only sight, but also smell.
Taste is poorly developed, because the lining of the oral cavity and the covers of the tongue are mostly horny and there is little space for taste buds on them. However, hummingbirds clearly prefer nectar and other sweet liquids, and most species reject very sour or bitter food. However, these animals swallow food without chewing, i.e. rarely keep it in the mouth long enough to subtly distinguish the taste.
Garden bunting
userfiles/5e.hortulana.mp3 ...
Half-footed goose
Our geese are clawed. The wide membrane completely hides the toes, turning the paw into a flipper. In Australia and New Guinea, geese are special, semi-footed. The membrane reaches only half of three...
Thrifty birds
If you carefully examine the tree trunks in the autumn forest, you will notice that round linden seeds, maple “spouts”, acorns, nuts are squeezed into the crevices of the bark, cracks and depressions...
And I didn’t believe it?
The organs of taste in birds are represented by taste buds located in some parts of the beak and tongue, close to the ducts of the glands that secrete a sticky or liquid secretion, since the sense of taste is possible only in a liquid medium. A pigeon has 30-60 of these taste buds, a parrot has about 400, and ducks have a lot of them. For comparison, we point out that in the human oral cavity there are about 10 thousand taste buds, in a rabbit - about 17 thousand. Nevertheless, birds clearly distinguish between sweet, salty and sour, and some, apparently, bitter. Pigeons develop conditioned reflexes to substances that create such sensations - solutions of sugar, acids, salts. Birds have a positive attitude towards sweets.
Smells are not as indifferent to birds as previously thought. For some of them, they play a very significant role when searching for food. It is believed that corvid birds, such as jays and nutcrackers, search for nuts and acorns under the snow, focusing mainly on smell. Obviously, the sense of smell is better developed than others in petrels and waders, and especially in the nocturnal New Zealand kiwi, which apparently obtain food guided mainly by olfactory sensations. Features of the microstructure of the olfactory receptors of birds have led some researchers to the conclusion that they have two types of odor perception: during inhalation, as in mammals, and the second during exhalation. The latter helps in the smell analysis of food that has already been collected in the beak and has formed a food portion in its rear part. Such a lump of food in the choanal area is collected in the beak of chickens, ducks, waders and other birds before being swallowed.
It has recently been suggested that the olfactory organ plays a role in the period preceding reproduction. Along with other changes in the body of birds, at this time there is a strong increase in the coccygeal gland, which has an odorous secretion specific to each species. In the pre-breeding time, members of one pair, along with other ritual positions, often take a position in which they touch each other’s coccygeal gland with their beaks. Perhaps the smell of her secretion serves as a signal that triggers a complex of physiological processes associated with reproduction.
The olfactory abilities of birds are questioned by many. The differences in the complexity of the organization of the olfactory organs between birds and mammals are too great for them to use this sense equally. Still, many ornithologists admit that tropical honeyguides find hives of wild bees partly by the peculiar smell of wax. During the breeding season, many tubenoses often regurgitate a dark, sharp-smelling liquid from their stomachs - “stomach oil”, which often stains nests and chicks. It is believed that in a dense colony, individual differences in the smell of this receptor help them find their offspring. The South American Guajaro nightjar probably also detects the fragrant fruits of trees by smell.
The olfactory analyzer is developed to varying degrees in different birds. But the mechanism of its functioning is largely the same as that of other vertebrates. This is confirmed, in particular, by electrophysiological studies.
Created: 11/22/2013 12:52
The rarest bird on Earth is the kiwi bird. Kiwis belong to the order of ratites. Its length is 50-80 cm. The body is evenly covered with hair-like feathers. The wings are reduced (they are not visible), there is no tail, the legs are short, with sharp claws. It lives in New Zealand and is a relative of the giant moa that was destroyed here about two centuries ago. The kiwi is a small dark rufous nocturnal bird that feeds on snails, worms and other burrowing animals. This is the only bird with a good sense of smell. She also uses antennae on her beak. Running quickly on strong legs, the kiwi constantly plunges its long beak with nostrils at the end into the ground in search of food. While clearing its “nose,” the bird sniffs, like a dog sniffing the soil.
At the beginning of the 20th century. it was almost completely exterminated because of its feathers, from which artificial flies for catching trout were made. It is these hair-like feathers that cover the body of this bird.
Since 1921 it has been under protection.
A hummingbird is the smallest bird on earth, sometimes no larger than a bumblebee (we are talking about a bee hummingbird). In addition, hummingbirds are also the smallest among warm-blooded animals (birds and mammals). The smallest species lives in Cuba and the island of Pinos. Adult males reach a length of 57 mm, with half of this length accounting for the beak and tail. Females are slightly larger than males. It weighs slightly less than a two-kopeck coin - 1.6 g. The hummingbird family is very large - it includes 319 species. She has the smallest eggs - smaller than a pea and weighing about 0.2 g (its size is 11.8 x 8 mm). Hummingbirds have a high body temperature - plus 43 ° C and the strongest heart of all birds. Hummingbirds eat the same way as spiders and bees. These birds constantly fly around spider gear and steal insects entangled in the web from their owners. In addition, hummingbirds forage for insects in flower cups. Using their long tongue, they “wash down” this meal with flower nectar. Hummingbirds, like bees, pollinate plants. They live mainly in Central and South America, but some species are also found in North America.
One of the most amazing birds in the world is the four-winged bird, which belongs to the nightjar family. The quadruped is found in Africa, from Senegal and Gambia in the west to Zaire in the south. The name was not given to it in vain: the male quadruptera in breeding plumage has a very long feather in each wing. In flight, these feathers, like flags, flutter either above the bird or behind it. It seems to the observer that the bird has four wings, and sometimes it seems that two small dark birds are chasing it.
The length of the pennant feather reaches 43 cm, with a body length with a tail of 31 cm and a wing length of 17 cm. It is believed that at the end of the mating season, the male breaks off the decorations that interfere with flight. Indeed, sometimes you can find birds with “stubs” of long feathers protruding from their wings. They remain until the next molt.
The opportunity to photograph the quadruped is very rare, because it, like all nightjars, flies at dusk. English zoologist Michael Gore found a male quadruptera in a daytime shelter, scared it and took a successful photo.
The highest speed in the animal world is achieved by the peregrine falcon during a rapid dive towards prey - 300 km/h or more!
Other birds are significantly inferior to the record holder. The eagle, for example, develops a speed of 190 km/h, the hobby and the black swift - 150, the swan - 90, the starling - 80, the swallow - 75 and the sparrow - 55 km/h. Note that the bird develops its maximum speed when attacking prey or, on the contrary, when escaping from a predator.
In normal flight, birds' speed is much slower.
In horizontal flight, there is no bird equal to the black swift (Apus apus). His usual speed is180 km/h The figure is slightly lower for the white-breasted needle-tailed swift( Hirundapus caudacutus), common in the Asian region. However, science knows of a rare species of swift under the Latin name chaetura, which demonstrates simply fantastic speeds - 335 km/h, easily overcoming powerful air resistance.
The marsh harrier is also very good (Circus aeruginosus ) - 288 km/h. This slender bird, half a meter long, flies, swaying in a peculiar way and staying as close to the ground as possible.
The best dive is the peregrine falcon from the falcon family. Back in the 1960s, ornithologists used electronics to accurately measure the maximum possible speed of a peregrine falcon diving. Note that in horizontal flight it does not exceed 100 km/h. Hunting for prey, the peregrine falcon falls like a stone at a speed of 290 to 380 km/h.
The slowest-moving bird is the American woodcock.(Philomela minor). Its maximum flight speed is 8 km/h.
The longest living birds are falcons. They live up to 160-170 years.
Other birds are significantly inferior to falcons in life expectancy, but many of them live no less than humans. So, a parrot in captivity can live up to 135 years. Kites and vultures live for more than 100 years. Vultures live up to 100 years, condors, golden eagles, wild geese and other birds live up to 80 years. Unfortunately, in nature, few birds live to their maximum age, since most of them do not die from old age.
Among poultry, the longest-living one is the goose. He lives to be a hundred years old. Chickens usually live much shorter - up to 30 years, ducks - up to 40 years.
A team of biologists has found that the sense of smell is as important to birds as vision or hearing. In addition, scientists were able to find out that sensitivity to odors depends on the habitat of birds: the more important the role of odors in finding food in a given area, the more “subtle” the birds’ sense of smell is. The researchers' work was published in the journal Proceedings of the Royal Society B.
In their work, Silke Steiger, an employee of the Ornithological Center at the Max Planck Institute, and her colleagues compared the representation of olfactory receptor genes in different bird species.
Olfactory receptors located on the sensory neurons of the olfactory epithelium are responsible for the perception of odors. The number of genes for these receptors is thought to correlate with the number of odors that a given organism can distinguish from each other.
In their research, biologists determined the number of olfactory receptor genes in nine species of birds. They found that their number can differ several times from species to species. Thus, the DNA of the southern kiwi contains six times more genes for olfactory receptors than the DNA of the blue tit or canary.
The scientists also tested how many of these genes were functional. In organisms that become less important to the sense of smell for survival, mutations accumulate in the genes of these receptors, which eventually turn them off. Thus, in humans, up to 40 percent of olfactory receptor genes are inactive. As Steiger and colleagues found, in birds, most of the receptor genes are functional, which may indicate the importance of smell for their life.
Scientists found another difference between the bird species studied in their brains: the more olfactory receptor genes a bird carried, the larger the size of its olfactory bulb, the brain structure responsible for processing information about smells.
Scientists have suggested that in birds, like mammals, the number of olfactory genes may depend on their habitat. For example, the southern kiwi, which cannot fly, looks for food on the ground. Kiwis are found only in New Zealand. The northern kiwi (Apteryx mantelli) inhabits the North Island, the common (A. australis), great gray (A. haasti) and rowi (A. rowi) inhabit the South Island, while the small kiwi (A. oweni) is found only on the island Kapiti, from where it is dispersed to some other isolated islands. Due to its secretive lifestyle, it is very difficult to find this bird in the wild.
Biologists believe that for this bird, smell can play the same, if not greater, role than vision. Kiwis mainly rely not on vision - their eyes are very small, only 8 mm in diameter - but on their developed hearing and sense of smell.
Among birds, condors also have a very strong sense of smell. Condors mainly use their excellent vision to search for food. In addition to searching for prey, they also carefully watch other birds nearby - ravens and other American vultures - turkey vulture, greater and lesser yellow-headed catarrh.
Catarths, with the help of their good sense of smell, find carrion, their main prey.
Condors have developed a so-called symbiosis, or mutually beneficial existence, with catarths: catarths have a very subtle sense of smell, capable of smelling the smell of ethyl mercaptan from afar - a gas released at the first stage of decay, however, their small size does not allow them to tear the tough skin of large victims as effectively as is possible Andean condors.
According to scientists, their results prove that the importance of smell in birds has so far been underestimated.
