Why doesn't a bird fall when it takes off? The force of attraction and the lifting force depends on the shape of the size of a bird's wing, the planning of birds, groups of feathers on the wings of birds, the flight qualities of birds, migratory birds, the flight altitude of birds. Flight of birds: semi-empirical theories of flight P

There are several types of bird flight: 1) gliding, or gliding, flight, when the bird flies with its wings more or less outstretched, without moving them, or descending from a height, maintaining or increasing speed due to the height, or maintaining a height and even rising up , but losing speed; 2) soaring, or sailing, flight, when a bird flies without moving its wings, maintaining both the height and speed of flight or even increasing them due to the force of air movement; 3) rowing or propelling flight (the usual type of flight), when the bird flaps its wings and thereby carries out support on the air and forward movement. This last type of flight has a number of varieties, of which vibration or pulsating flight deserves special attention, when the bird, with the help of extremely fast movements of the wing, either hangs in the air or moves and, moreover, can not only rise vertically, but even move backward.

The theory of bird flight has now been developed in great detail in connection with the successes of aeronautics. In general, a flying bird obeys the laws of the movement of plates in the air. The theory of the movement of such plates and numerous experiments have established the following:
1. If the plate moves in the air at a certain angle α (angle of attack) to the axis of motion (Fig. 487), then the pressure of the oncoming air on the plate R will be directed almost perpendicular to it, decomposing into lift force P and drag Q. Lift force and drag increase in direct proportion to the area of ​​the plates and the square of the speed of movement.
To obtain high speeds, a small angle of inclination of the plate is more advantageous, and at high speeds, increasing the angle α to certain limits leads to an increase in lifting force.
The center of pressure (the point of application of pressure on the plate from below, the point of support in the air) moves closer to the front edge of the plate, the faster it moves.
2. In oblong plates, the pressure depends on the position of the plate, namely, plates with their long side perpendicular to the direction of movement receive greater pressure from below, and therefore are more advantageous for flight.
3. Concave plates provide greater lifting force than flat ones, and:
a) the direction of the resultant is inclined forward, as a result of which such a plate retains its lifting force not only with a horizontal, but even with a chord slightly inclined forward;
b) if the front side of such a plate is thickened, then it not only does not increase drag, but, on the contrary, has a beneficial effect on lift and drag (Fig. 488), while the same thickening of the rear side is very unfavorable;

c) the best bends of curvature give 1/10-1/15 of the arrow of deflection;
d) for stability, it is useful to bend the back of the plate slightly upward.
4. The stability of the moving plate is achieved:
a) the location of the center of gravity below the plane of support and the fact that the points of application of the resultant aerodynamic forces coincide with the center of gravity;
b) the presence behind the main bearing plane of an additional plane of the so-called stabilizer.
In general, the horizontal flight of a certain speed of a flying object with wings (birds or airplanes) is determined by the following formulas:
1) P = G = CypSV2
2) Q = F = CxpSV2,
where P - lift force, G - weight, Q - drag, F - traction force, p - air density, S - bearing surface area, F - speed, Cy and Cx proportionality coefficients (lift and drag) and mainly depending on the qualities of the load-bearing surface (the shape of the wings) and the angle of attack.
The plane of support in the air in birds is represented by the wings and tail. Bird wings satisfy exactly all of the above requirements; they are elongated in the direction perpendicular to flight, representing plates curved upward with a thickened anterior edge and a straightened posterior part. The latter is elastic and can bend upward. The tail acts as a stabilizer.
The general body shape with a sharp beak, a small head and close-fitting plumage represents the least resistance to air.

The center of gravity in birds lies significantly below the plane of support, which is achieved by the high position of the wing and the fact that all the heavy organs of the bird - the digestive organs and pectoral muscles - are located below, and the light and air sacs lie above. This position of the center of gravity gives the bird's aircraft greater stability. The very plane of support in the air, i.e., the wings and tail, can easily decrease at will, which is achieved by greater or lesser spreading of the wings and tail. Thus, the bird can change the ratio of its wing area to its body weight. Meanwhile, the greater the plane of support against the air, the greater the resistance experienced by the horizontal plane falling vertically downwards. If such a plane moves forward, then it encounters air resistance, which increases in proportion to the squares of the speed and in direct proportion to the cross-sectional plane drawn at right angles to the direction of movement.
Thus, the faster a bird flies, the easier it is for it to stay in the air. But since a flying bird also has to overcome air resistance in the direction of movement, it is natural that the bird, when moving forward, gradually loses the speed it once acquired; along with the decrease in speed, the air resistance from below will decrease, and the bird will be forced to descend. In order not to fall, the bird must regain speed, correspondingly increasing the traction force by flapping its wings.
When a plane moves, the angle it forms with the axis of movement, the angle of attack, plays a big role. The magnitude of this angle, as we have seen, determines the force that lifts the bird upward, as well as the drag.
Changes in this angle are achieved by moving the center of gravity. As the flight speed increases, the bird must shift its center of gravity more and more forward so that the center of support coincides with the center of gravity.
Gliding, or gliding, flight is possible only during non-horizontal flight, precisely when it is directed obliquely downwards. The driving force in this case is the gravity of the bird. The ratio of the wing area to the weight of the bird determines, at a certain speed and at a certain position of the wing in relation to the oncoming air flow (angle of attack), the gliding angle, i.e., the angle of flight direction to the horizontal plane. The larger the wing area, the lighter the bird's weight and the faster the flight, the smaller the glide angle can be.
By reducing the area of ​​the wings, the bird can achieve greater gliding speed and can use this speed of movement to rise again to a known height.
Birds control their gliding flight in different ways. Firstly, a bird can easily increase or decrease the area of ​​the plane of support on the air by spreading or folding its wings and tail; secondly, it can move the center of support in the air in relation to the center of gravity in two ways: either, while maintaining the position of the center of gravity, change the position of the center of support by bending the wings, spreading the tail, etc., or transfer the center of gravity by stretching the neck forward or pulling it back; the latter, however, is important only in birds with a long neck. This movement of the center of support in relation to the center of gravity can lead to a change in the angle of attack of the wing, i.e., the angle of the wing plane to the oncoming air movement, and at the same time to a change in the gliding angle.
In birds of different sizes, the area of ​​the wings changes in proportion to the square, and the weight of the bird changes in proportion to the cube.
From this and from the above formulas it can be seen that as the bird triples in size, the wing area increases 9 times, and the weight of the bird increases 27 times. Consequently, the bird must also increase its lifting force by 27 times. Since the bearing surface of the wing will increase by 9 times, to maintain altitude it is necessary to increase the speed by √3 times. In this case, the drag will also increase by 27 times, and the bird must accordingly do more work to increase the speed by √3 times.
It follows from this that large birds spend much more energy than small birds. This, apparently, puts a certain limit on the increase in the size of birds in general. This is probably why large birds often use soaring rather than rowing flight.
Birds quickly descending fold their wings and spread their tail; the center of air support moves significantly backward compared to the center of gravity, and the gliding plane bends with its front side down. On the contrary, when a bird wants to level out its gliding flight or rise upward, it spreads its wings and moves them forward: the center of support on the air becomes in front of the center of gravity, and the front side of the gliding plane rises up; the same effect is achieved by lowering the tail down. Turning to the right and left is achieved either by bending the corresponding wing, or by turning the head, or by stretching the neck to the corresponding side, or by turning the loose tail in the opposite direction.
Rowing, or propelling, flight. With this type, the conditions of gliding flight are maintained; They are also joined by a translational force - the traction force, which is achieved by flapping the wings. The faster the bird moves, the easier it is for the bird to stay in the air; Therefore, it is clear that the bird has to expend the most energy to obtain the initial speed. The headwind in this regard provides the bird with some help, since with a certain force and a certain ratio of the wing area to the weight of the bird, the wind can lift the bird upward like a kite. Therefore, all birds in the wind rise on their wings, standing against the wind. In other cases, the initial speed is achieved by running or jumping, after which the bird rises upward. Or, finally, the bird has to beat its wings frequently and forcefully to get its initial speed. In this case, the wings sometimes hit the ends of one another behind the back, producing a characteristic sound in different species of birds when rising. The energy expenditure during ascent is so great that birds that have to climb and descend several times in a row easily become exhausted. There are birds that cannot rise from a horizontal surface at all and obtain the initial speed required for flight by falling down from high objects, such as swifts.
To lift a bird into the air, it is necessary that both wings be able to capture a certain mass of air relative to the weight of the body. From this it is clear that birds with small short wings flap their wings much more often than birds with large wings. So, when flying, a sparrow makes 13 flaps per second, a duck - 9, a crow - 3-4, a stork - 2 and a pelican - 1 1/6.
Birds generally spend less time raising their wings, so on average the time required for raising the wing is divided by the time of lowering as 2:3.
As can be seen from the attached snapshot (Fig. 489), during flight the bird moves its wing not only downward, but also forward.

When the wing is raised, air resistance is reduced by the fact that the wing is convex on top, that when raised it is slightly bent in the fold and directed with the rear downwards, and, finally, by the fact that the flywheels, due to the greater width of the internal vanes, diverge, allowing air to pass through.
Having obtained a sufficient forward flight speed, the bird no longer needs to expend much energy, it only needs to maintain the acquired speed; since the air resistance of the moving surface from below increases, as we have seen, in proportion to the square of the speed of movement, then a bird in fast flight, other things being equal, will rise upward. Hence, fast-flying birds flap their wings less often and reduce the surface of the support plane by folding their wings and tail. So, a jackdaw, for example, when rising, makes about five strokes per second, and when scattered, only three strokes.
Many small birds, having made several quick flaps of their wings and risen to a certain height, then fold their wings, fly for several seconds without flapping, lower themselves a little, then flap their wings again, rising to the original height, stop flapping again, etc. Here, Due to their low weight and a more favorable ratio between weight and wing area, small birds during rowing flight, flapping their wings, very quickly increase their lifting force.
The soaring flight of birds, or soaring, has now been studied very well thanks to the developed theory of flying machines without propulsion devices - gliders. The bird does not move its wings at all, and yet it not only maintains speed, but can rise upward. Such flight is conceivable in the case where the bird uses horizontal or, even better, non-horizontal air currents or the heterogeneity of air currents in the horizontal and vertical directions. Various air vortices, vortices, air pulsations (the so-called air turbulence) are caused by various reasons: for example, uneven heating of different parts of the earth, due to which warm air rises up and cold air falls down; obstacles that air currents encounter in their path in the form of mountains, forests, waves, etc. To use air currents, certain conditions are necessary. First, a known absolute and relative size of the wings is needed. We find well-flying birds, which can soar even with the slightest, seemingly imperceptible air movements, precisely among large species of birds with powerful wings. These are the vultures of the Old and New Worlds, inhabitants mainly of the mountains, where, as we see, air turbulence should be especially strong. Further, eagles and other large predators, storks, crows, gulls, petrels, pelicans and many others, soar well. All of these are either large birds with powerful wings, or small and medium-sized birds with very long wings.
Secondly, a certain specific structure of the wings is necessary, namely: they must be long enough compared to the width; let’s assume here we find two types of wings. We find the first type in mainland birds: the wings are relatively wide, and the primary flight feathers can be spread wide. Seabirds - petrels and gulls - have very long, narrow and sharp wings. In both cases, the birds control their flight in the same way, every minute changing the size of the surface of the wings according to need: the first - by spreading the flight feathers more or less and spreading the tail, the second - by bending the wing.
Interestingly, soaring in most cases is accompanied by whirling. At the same time, the bird describes larger or smaller circles over the same place, now rising and now falling without the slightest movement of its wings.
In a strong wind, the bird allows itself to be carried back, keeping in the direction of the oncoming wind, gradually rising and reducing the speed of movement. Having reached the highest point, the bird turns sharply back and, gradually descending, acquires considerable speed so that, having described an arc, it again stands against the wind and rises again in its original place.
Pulsating flight is characteristic of many small birds: kinglets, warblers, flycatchers, but it reaches great specialization in nectar-feeding birds, sunbirds (Nectariniidae) of the Old World and especially hummingbirds (Trochilidae). Having flown up to a flower, hummingbirds quickly flapping their wings, like hawk moths, hang in the air in front of the flower until they suck the nectar from the flower. At the same time, they make up to 50 beats per second, so that the movement of the wings is impossible to notice, and it seems that the bird is surrounded by a foggy halo. Hummingbirds can not only rise vertically into the air, but are also the only birds that have the ability to move backwards in the air.
Similar to pulsating flight is the hanging, or fluttering, flight characteristic of many predators - kestrels, buzzards, as well as terns and some other birds. Quickly flapping their wings, the birds hang in the air over one place, looking for prey. Larks also have the ability to hang in the air while singing.
The speed of flight is quite different in different species, as well as in the same individual, depending on the flight conditions. For carrier pigeons, the speed is set at 1000-1500 m per minute.
The fastest flying bird is considered to be the swift of the genus Chaetura - 2400 m per minute; other birds have a significantly lower flight speed, namely: homing pigeons - 1320 m (and up to 1950 m) per minute, starlings - 1230 m, kingfisher - 960 m, chaffinch - 870, crow - 840 m per minute. In general, it should be noted that the above figures give an average normal speed, while at times the flight speed can be much higher, for example, that of a falcon chasing prey or a crow trying to avoid danger. Thus, it was found that a cormorant, pursued by an airplane, flew 15 km at a speed of 105 km per hour, while its average flight speed was about 70 km per hour.
In general, small birds develop greater flight speed, although each beat of the wings of a large bird has a greater effect in flight. Thus, among a squad of geese, a teal weighing 330 g flies at a speed of 1980 m per minute, a mallard weighing 1250 g flies at a speed of 1740 m per minute, and a gray goose weighing 3500 g flies at a speed of 1170 m per minute.
The duration of flight without rest in birds is amazing. For example, with the exception of a short rest at night on long summer days, swifts fly in the air almost the whole day. During migration, some waders fly over a distance of 3000 km without resting.

Ecological principle of classification of flight types based on the biological significance for birds of a particular manner of movement in the air. This classification does not coincide at all with aerodynamic, often combines several types of flight discussed above, allowing them to overlap. Both classifications can be used in practice, for example, when observing birds, in parallel, since the first describes the capabilities of a bird as a flying machine, and the second helps to understand the purpose and purpose of specific forms of behavior.

According to environmental principles, classifications vary search, reconnaissance, transit, current flights and some others.

Search flight associated, as its name implies, with the search for food over vast expanses of water or land, often at high altitudes. Albatrosses and petrels travel hundreds of kilometers over the sea in search of food, over coastal areas of the seas, small reservoirs and land - gulls and terns, over the foothills, steppes and tundra - skuas, harriers, kites, buzzards, and eagles. The search flight is always leisurely, long, including all types of soaring, flapping and fluttering when a careful search for food is necessary. The most typical search flight is for tubenosed birds, gulls and diurnal raptors.

In many ways it is similar to the search one, but, unlike it, it is interrupted by long periods of feeding on the ground. If a buzzard or kestrel, having caught a field rodent, continues leisurely patrolling of their hunting grounds, then the stork, having found a suitable place to collect food, “fishes” for a long time, walking around the chosen area, and only then moves to another. Such airborne assaults are carried out cranes, herons, vultures, crows.

Transit flight most closely resembles regular flights with a specific purpose and to a specific location. Everyone is familiar with huge winter flocks of jackdaws and crows, flying every evening from garbage dumps and vacant lots near Moscow to spend the night in the city center, and back in the morning.

Similarly, in the morning and evening certain air routes operate ducks The transit flight always takes place without stops or delays; he is fast and straightforward, because the path does not always go through safe places.

Current flight- this is a specialized type of flight that is included in the general species stereotype of the current. Its main goal is to attract a female during the breeding season. Not all birds have current flight, but in those that do, it is usually accompanied by specific sounds and poses characteristic of the species. Nothing resembling lek flight can be seen after the end of the nesting period. Often this seasonal behavior is so unique that it is simply difficult to believe that this is a familiar bird. Hidden silent forest sandpiper woodcock in the spring it flies over forest clearings and clearings with a special slow flight, which hunters call draft. His relative snipe, usually camouflaged in hummocky swamps, climbs high into the sky and from there rushes headfirst to the ground, spreading its hard, springy tail like a fan, in the feathers of which the wind vibrates loudly. Lapwing over the spring field makes dizzying turns from wing to wing, accompanying himself with his voice. skylark also sings his familiar song during the current flight.

Lark

Grouse

Escape flight- a rapid flight, interspersed with takeoffs and landings. In a forest or field, unfortunately, we most often and most easily observe precisely this type of flight, which is far from the most interesting for a naturalist. Usually it occurs at maximum speed, as a result of which the bird quickly disappears from view and it is not always possible to see it. A typical example is a meteoric rise hazel grouse, after which the bird seems to dissolve in the branches, becoming completely inaccessible to the eye, although it flies no further than the nearest spruce.

Intermittent flight, also known as aft flight, common during feeding for small birds, especially forest and bush birds. It is relatively easy to observe. In winter you can often see feeding movements flocks of tits accompanied nuthatch, woodpeckers and pikas; siskins and redpolls, clinging to the tops of birch and alder trees; in summer it is easy to observe the feeding flights of warblers, searching every branch, “grazing” with short flutters finch and starling, hunting white wagtails and pied flycatchers.

Not all bird species are clearly located at these nodal points; many types of flight can be characterized as intermediate or combined.

Throughout the nineteenth century we observe two practically unrelated processes. On the one hand, flight enthusiasts, mostly practical people, developed their own rather primitive theories of bird flight and tried to apply their findings to the requirements of human flight. On the other hand, representatives of science developed the mathematical theory of fluid dynamics; this development was unrelated to the problem of flight and did not provide much useful information to those who aspired to fly.

Research aimed at realizing the human desire to fly concerned mainly two problems: first, to determine the power required for flight; secondly, find out the most rational shapes of the wings. Let us briefly consider both tasks and the dominant points of view during that period.

Regarding the question of power required for flight, the fact that birds actually fly through the air has provided some solid support for the speculation. Quite early it was recognized that two characteristic quantities should play an important role in calculations. One of them is the ratio between the weight W and the wing area S. We call this ratio the specific load on the wing: The second value is the ratio between the weight W and the available power P. The ratio is called the load per unit power. In the case of bird flight, available power is the muscular energy the bird can exert in flight. It can be assumed that the latter value is approximately proportional to the weight of the bird.

The main question then was to estimate the required power and compare it with the available power. The required power is calculated based on the assumption that a soaring bird, without using its wings, would lose a certain height per unit time; it is called the rate of descent. In order to fly horizontally, a bird must perform at least as much work as is necessary to raise its body at a speed sufficient to counteract the rate of descent. This estimate led to the conclusion that power required per unit weight (i.e., the reciprocal of load per unit power) is proportional to the square root of the specific wing load.

The general form of this rule was confirmed by a more detailed analysis by Charles Renard (1847-1905), one of the leaders of early aeronautics in France. He expressed the power required for level flight as the sum of the power required to maintain and the power required to propel the aircraft forward, i.e., drag multiplied by speed. Its formula is exactly the same as those used in modern aircraft design. He then calculated the speed at which the required power was at its minimum and plugged that value into his formula. The result was as follows:

and corresponds to the expressions obtained earlier for the minimum required power for horizontal flight (p denotes air density).

The constant in Renard's formula depends on the assumptions made a) for the law of support and b) for the drag coefficient of the aircraft. The first assumption is very important.

If Newton's law of resistance is used to calculate the supporting force, then for the required power, as we indicated above, a terrible figure is obtained. The calculation result is more plausible if the lift force is calculated using one of the empirical formulas found based on experiment. According to Henry, a contemporary of Renard, the constant in the equation would be 0.18.

If we apply Renard's formula to the flight of birds, it is obvious that the required power per unit weight of the bird increases with the load on the wing. It's interesting to see how birds' wing loading actually changes with their overall weight. In Fig. 10 contains information I have prepared based on data in La Machine animal, a famous book written by the famous French physiologist Etienne Jules Marey (1830-1904). The abscissa is the weight in pounds and the ordinate is the wing loading in pounds per square foot; both are plotted on logarithmic scales. A distinction is made between birds that normally soar and those that flap their wings. In general, it is clear that the load on the wing increases with increasing weight. Since we are inclined to think that the power which a bird can exert through its pectoral muscles is approximately proportional to its weight, it follows that flight is a greater problem for a large bird than for a small one. Therefore, we conclude that there is a certain size beyond which a living creature cannot fly.

The famous German physicist Hermann von Helmholtz (1821-1894) examined the law of similarity of flying living creatures in an article published in 1873. He suggested that the weight of an animal is proportional to the cube, and the area of ​​its wing is proportional to the square of its linear size. According to this assumption, the wing load

Rice. 10. Load on the wing of birds. Wing loading in pounds per square foot is plotted against weight in pounds; both are on a logarithmic scale. White circles represent birds that usually soar, black circles those that flap their wings. A straight line slope of 1:3 corresponds to Helmholtz's law of similarity.

increases in proportion to the cube root of the weight. This relationship is represented by a straight line with a 1:3 slope in Fig. 10, where a logarithmic scale is used. Thus, the particular law proposed by Helmholtz seems to be confirmed if we consider only soaring birds.

There was a joke in German academic circles about how a student failed Helmholtz's exam because he could not prove that human flight was never possible. I doubt that the story is true in this version. Perhaps the student was asked a question about the possibility of human flight using his muscle energy. After considering the effect of weight gain on the ability to fly in the animal kingdom, Helmholtz concluded that man has a very low chance of flying using his muscular energy.

Until now, there has not been a single successful attempt to propel an aircraft using human muscle energy. In 1937, Italians Bossi and Bonomi successfully maintained level flight in a propeller-driven aircraft to a distance of approximately 2,600 feet, although air

Rice. 11. Wing profiles studied by Horatio Phillips. (From American Engineer and Railroad Journal, 67 (1893), 135.)

the screws were driven only by muscle energy. However, the plane could not take off due to muscle energy alone. Some people believe that by improving the aerodynamics of the wings and engine and reducing the weight of the structure, it would be possible to design an airplane powered by muscle power.

In addition to closely studying the flight of birds, early researchers in the field of aerodynamics were mainly concerned with identifying particularly suitable wing shapes. Similar studies were carried out both in wind tunnels and using real glider flights. In Fig. Figure 11 shows a series of wing profiles studied in the Phillips wind tunnel. Note that Phillips studied curved surfaces, which turned out to have more advantages than flat plates. These observations were fully confirmed by Otto Lilienthal (1848-1896) with his experiments in glider flights. Researchers of that period considered two conclusions important: first, that a curved surface shows a positive lift in the case of a zero angle of attack, that is, if the leading and trailing edges are located at the same height; Secondly,

that the aerodynamic quality of curved surfaces in some cases exceeds that of flat plates. At the time, there was no theoretical explanation for why curved surfaces produce lift at a zero-angle flight attitude. We will see later how the modern theory of lift successfully explains this fact. However, it is surprising to find the following relatively late (1910) comment in Richard Ferris's famous book How It Flies: "Recent research (he describes the design of Henson's 1843 airplane) has shown that the upper surface of the airplane must be convex in order to increase the effect of lift. This is one of the paradoxes of flying cars that no one can explain."

Lilienthal especially emphasized the importance of curved wing surfaces. He made many other interesting observations in aerodynamics; for example, he found that natural wind is more favorable for soaring flight than a perfectly uniform air flow. This beneficial effect can be achieved by using updrafts, which often exist in natural winds. However, Lilienthal discovered that sometimes the lift of a natural wind, even in the absence of updrafts, can exceed that of a uniform air flow. Only recently has it been recognized that this effect arises from the transverse velocity gradient that typically dominates natural winds, at least in the lower atmosphere.

Some of the theoretical ideas of the Lilienthal brothers, Otto and Gustav (1849-1933) were rather vague. They spent a lot of time studying the possibility of creating negative drag, that is, moving forward using a special wing profile shape without providing power. A few years after the death of his brother Otto in an accident in 1896, Gustav Lilienthal actually published a “theory” of this phenomenon, which undoubtedly contradicts the principles of mechanics. In my persistent search for scientific truth in my youth, I once called him "the great man's insignificant brother," an expression which I believe offended him. I regret it now when I look back on my teenage years in the development of aerodynamic science.

In the USA, the outstanding civil engineer from Chicago Octave Chanute (1832-1910) carried out a huge number of experiments on flights

on gliders. His attention was mainly focused on the issue of sustainability. It is interesting to note that a month before Otto Lilienthal's accident, he expressed his opinion that the Lilienthal glider was unsafe.

Rice. 12. Model of the airplane of Alphonse Penaud. (From American Engineer and Railroad Journal, 66 (1892), 508.)

In addition to manned gliders, flying models with or without engines have provided important aerodynamic information. The model presented by Alphonse Penaud (1850-1880) appears to be the first model to successfully achieve stability using a horizontal tail surface located at the rear (Fig. 12). Penaud believed that a passenger airplane with a gross weight of 2,600 pounds and an engine of 20 to 30 horsepower could be constructed according to his inventions. His life and work are a tragic chapter in the history of aeronautics. He was paralyzed, so he could only continue his research at home; poverty, poor health and lack of recognition broke him to such an extent that at the age of thirty he committed suicide.

The Wright brothers, who made the first mechanical flight in a manned airplane, and Samuel P. Langley (1834-1906), who came close to achieving a similar practical result, followed the directions we have outlined in this short sketch. Langley emphasized the analogy with bird flight and was fully aware that Newton's theory of air resistance could not be correct if human flight in a heavier-than-air apparatus was possible. After the model flight

with a mechanical drive, he came to the decision to build a manned vehicle. He was lucky in that he had an assistant with a mechanical genius, who was rarely given due honor. This assistant was Charles M. Manley (1876-1927), a graduate of Cornell University, who built a gasoline engine powerful and light enough to serve this purpose.

Wilbur (1867-1912) and Orville (1871-1948) Wright were not professional scientists. However, they were familiar with practical ideas in the field of aerodynamics developed by various researchers before them, and, in addition to the remarkable talent of the designers, they had the opportunity to use experiments with models for their full-scale design. In fact, they used a simple and small wind tunnel for this purpose. Moreover, they performed almost a thousand glider flights.

It is interesting to consider the main technical characteristics of the Wright brothers' first aircraft in the light of the theoretical reflections given above. Their aircraft had a gross weight of 750 pounds and a wing area of ​​500 square feet, so the wing loading was 1.5 pounds per square foot. This wing load is slightly greater than that of the vulture (Fig. 10), and seventeen times less than, for example, a fully loaded Douglas DC-3. The net available power based on the 12 horsepower engine with 66 percent propeller efficiency stated by Orville Wright can be estimated at 4,300 ft-lbs per second. Therefore, the available power per unit weight was 5.7 feet per second. According to Renard's formula, the power required per unit weight would be 4.4 feet per second at the above wing load. It is also interesting to note that Renard, in a paper published in January 1903, calculated that the engine of a manned aircraft should not be heavier than 17 pounds per horsepower. The engine used by the Wright brothers was 15 lb. horsepower.

A year before the Wright brothers' first successful flights, the German applied mathematician Sebastian Finsterwalder (1862-1951) published an excellent overview of the state of knowledge in the field of aerodynamics at that time. This article contains a lot of interesting material and a large number of links to sources related to this topic, which I could only briefly touch on here.

Bird flight can be divided into two main categories: soaring, or passive, flight and flapping, or active, flight. When soaring, a bird moves in the air for a long time, without flapping its wings and using rising air currents that are formed due to uneven heating of the earth's surface by the sun. The speed of these air currents determines the bird's flight altitude.

If the upward moving air flow rises at a speed equal to the speed of the bird's fall, then the bird can float at the same level; if the air rises at a speed exceeding the speed of the bird’s fall, then the latter rises upward. Using differences in the speed of two air flows, the uneven action of the wind - its strengthening and weakening, changes in wind direction, air pulsations - a soaring bird can not only stay in the air for hours without spending much effort, but also rise and fall. Land soaring species, such as carrion-eating vultures and others, usually use only rising air currents. Marine soaring forms - albatrosses, petrels, feeding on small invertebrates and often forced to descend to the water and rise - usually use the effect of the wind, differences in the speed of air flows, air pulsations and turbulence.

For soaring birds characterized by large size, long wings, long shoulder and forearm (great development of the supporting surface of the secondary flight feathers, the number of which in vultures reaches 19-20, and in albatrosses even 37), a rather short hand, relatively small heart sizes (since passive flight does not require increased muscle work). The wing can be either wide (terrestrial species) or narrow (sea species). Flapping flight is more complex and varied than soaring flight. It is worth comparing the flight of a swift, the flight of a crow slowly moving its wings, a kestrel fluttering in the air and a peregrine falcon swiftly rushing at its prey, a quickly flying duck and a pheasant heavily flapping its wings to be convinced of the validity of this remark. There are various and rather controversial attempts to classify the different types of flapping flight, which we will not dwell on here.

A bird usually does not use one type of flight, but combines them depending on the circumstances. It should also be borne in mind that flight movements consist of phases that successively replace one another. The flapping of the wings is followed by phases when the wing does not produce rowing movements: this is gliding flight, or soaring. This flight is used mainly by birds of medium and large sizes, with sufficient weight. Small birds usually work energetically with their wings all the time or at times can fold their wings, pressing them to the body. The latter is especially typical for finches. Acceleration in flight is achieved by the bird by increasing the weight load of the supporting surface, for which it is necessary to fold the wings slightly. The slow-flying bird has a fully unfurled tail and outstretched wings. As the movement accelerates, it slightly folds the flight feathers, and in all well-flying birds they form a continuous surface (in the falcon, gull, swift, swallow, etc.).

Wind is of great importance for the speed of movement of birds.. Generally speaking, a tailwind or somewhat crosswind is favorable for flight, but a headwind is favorable for takeoff and landing. A tailwind during flight helps to increase the bird's flight speed. This increase is quite significant: for example, based on observations of pelicans in California, it was established that an increase in air speed from actual calm to 90 km/h contributed to a change in the flight speed of pelicans from 25 to 40 km/h. However, a strong tailwind requires a lot of effort from the bird to maintain active flight control.

The duration and speed of flight of birds is very great, although exaggerated ideas are usually common in this regard. The very phenomenon of flights shows that birds can make long movements. European swallows, for example, winter in tropical Africa, and some waders nesting in North-Eastern Siberia fly to New Zealand and Australia for the winter. The speed and altitude of birds' flight are significant, although they have long been surpassed by modern flying machines. However, the flapping wing of a bird gives it many advantages, primarily in maneuverability, compared to modern aircraft.

Modern technical means (observations from aircraft, high-speed photography, radars, etc.) have made it possible to more accurately determine the flight speeds of birds. It turned out that when migrating birds, on average, they use higher speeds than when moving outside the migration season. When migrating, rooks move at a speed of 65 km/h. The average speed of their flight outside of migration time - during the nesting period and wintering - is approximately 48 km/h. During migration, starlings fly at a speed of 70-80 km/h, at other times 45-48 km/h. Based on observations from airplanes, it has been established that the average speed of movement of birds during migration ranges between 50 and 90 km/h. Thus, gray cranes, herring gulls, large sea gulls fly at a speed of 50 km/h, finches, siskins - 55 km/h, killer whale swallows - 55-60 km/h, wild geese (different species) - 70-90 km /hour, wigeons - 75-85 km/hour, waders (different species) - on average about 90 km/hour. The highest speed was observed for the black swift - 110-150 km/h. These figures refer to spring migrations, which are the most intense and probably reflect the highest flight speeds of birds. Autumn migrations proceed much more slowly, for example, the flight speed of storks during autumn migrations is hardly half the speed of their spring movement.

The question of the flight altitude of birds remained unclear for a long time. The old idea that bird movements usually take place at high altitudes (500-1600 m above sea level) was questionable. However, astronomical observations have shown that, in all likelihood, the maximum flight altitude of birds reaches 2000 and even 3000 m. To some extent, this has been confirmed by the use of radar. It turned out that migrations in spring take place at higher altitudes than in autumn, and that birds fly at higher altitudes at night than during the day. Passerine birds, such as finches, fly at altitudes somewhat lower than 1500 m; larger passerines, such as blackbirds, are at an altitude of 2000-2500 m. Waders fly at an altitude of about 1500 m. Although flight is the main and most characteristic method of movement for birds, they also have other very diverse methods of movement.

The well-known divisions of birds into aquatic, terrestrial, and arboreal indicate known differences between these groups in relation to movement.

When studying the topic “Bird Class”, the children for the first time become acquainted with such an important concept as warm-blooded. It is very important that students understand that maintaining a constant body temperature is ensured by the interaction of a number of physiological systems in the body. A good knowledge of this material is necessary to explain complex evolutionary and ecological problems.

Teacher.

- Guys, why are there fewer birds in the forest in winter than in summer?
(Suggested answers: little or no food(for insectivorous birds), a lot of snow, cold.)
– Can feather cover protect birds from frost in winter? ( Maybe, but only partially.)
The main questions we need to answer in today's lesson are: What warms a bird's body? How do they maintain a constant temperature? Where do they get energy for flight?
– How is heat generated in general? ( Suggested answers: during the combustion of organic substances, which occurs in the presence of oxygen.)
– What makes the car move? How do organisms move? ( Due to the energy also generated during combustion(oxidation)organic substances with the participation of oxygen.)
How much energy do birds need? After all, they can fly long distances and reach high speeds. (Working with tables.)

Table 1. Distances covered during flights

Table 2. Wing surface area and load on them

For comparison, the glider model has a wing load of 2.5 kg/m2.

Table 3. Wing flapping frequency

Table 4. Maximum flight speed

The smaller the bird, the more food per gram of body weight it requires. As the size of an animal decreases, its mass decreases faster than the body surface area through which heat loss occurs. Therefore, small animals lose more heat than large animals. Small birds eat an amount of food per day equal to 20–30% of their own weight, large birds – 2–5%. A tit can eat as many insects as it weighs in a day, and a tiny hummingbird can drink an amount of nectar that is 4-6 times its own weight.

Repeating the stages of food breakdown and the features of the respiratory system of birds, we fill out diagram No. 1 step by step.

Work progress when filling out the diagram

The intense motor activity of birds requires large amounts of energy. In this regard, their digestive system has a number of features aimed at efficiently processing food. The beak serves as the organ for capturing and holding food. The esophagus is long, in most birds it has a pocket-like extension - a crop, where food is softened under the influence of crop fluid. The glandular stomach has glands in its wall that secrete gastric juice.
The muscular stomach is equipped with strong muscles and is lined on the inside with a strong cuticle. Mechanical grinding of food occurs in it. The digestive glands (liver, pancreas) actively secrete digestive enzymes into the intestinal cavity. The broken down nutrients are absorbed into the blood and distributed to all cells of the bird's body.
How long does it take for birds to digest food? Small owls (little owls) digest a mouse in 4 hours, a gray shrike in 3 hours. Juicy berries pass through the intestines of passerines in 8–10 minutes. Insectivorous birds fill their stomachs 5–6 times a day, granivorous birds – three times.
However, the absorption of food and the entry of nutrients into the blood is not the release of energy. Nutrients need to be “burned” in tissue cells. What system is involved in this? ( Light, airy bags.)
– Muscles must be well supplied with oxygen. However, birds cannot provide the required amount of oxygen due to a large amount of blood. Why? ( Increasing the amount of blood would increase the bird's mass and make flight more difficult.)
Intense supply of oxygen to tissue cells in birds occurs due to “double breathing”: oxygen-rich air passes through the lungs both when inhaling and exhaling, and in the same direction. This is ensured by a system of air sacs penetrating the bird’s body.
In order for blood to move faster, increased blood pressure is necessary. Indeed, birds are hypertensive. In order to create high blood pressure, the heart of birds must contract with great force and high frequency (Table 5).

Table 5. Heart mass and heart rate

As a result of the oxidation (combustion) of nutrients, energy is generated. What is it spent on? (We finish filling out diagram No. 1).

Conclusion. An active oxidative process helps maintain a constant body temperature.
High body temperature ensures a high level of metabolism, rapid contraction of the heart muscle and skeletal muscles, which is necessary for flight. High body temperature allows birds to shorten the development period of the embryo in the incubated egg. After all, incubation is an important and dangerous period in the life of birds.
But constant body temperature has its drawbacks. Which? We fill out diagram No. 2.

So, maintaining a constantly high body temperature is beneficial for the body. But for this you need to consume a lot of food, which you need to get somewhere. Birds had to develop various adaptations and behavioral traits that allowed them to obtain sufficient food. Here are some examples.
Next, students make reports on the topic “How different birds get their food” (their preparation could be homework for this lesson).

Pelican fishermen

Pelicans sometimes fish together. They find a shallow bay, cordon it off in a semicircle and begin to flap the water with their wings and beaks, gradually narrowing the arc and approaching the shore. And only after driving the fish to the shore do they begin fishing.

Owl hunting

Owls are known to hunt at night. The eyes of these birds are huge, with greatly dilated pupils. Through such a pupil, even in poor lighting conditions, enough light enters. However, it is impossible to see prey - various small rodents, mice and voles - from afar in the dark. Therefore, the owl flies low above the ground and looks not to the sides, but straight down. But if you fly low, the rustle of the wings will scare away the prey! Therefore, the owl has soft and loose plumage, which makes its flight completely silent. However, the main means of orientation for night owls is not vision, but hearing. With its help, the owl learns about the presence of rodents by squeaking and rustling and accurately determines the location of the prey.

Armed with a stone

In Africa, in the Serengeti nature reserve, biologists observed how vultures obtained food for themselves. This time the food was ostrich eggs. To get to the treat, the bird took a stone with its beak and threw it forcefully onto the egg. The strong shell, which could withstand the blows of the beak of even such large birds as vultures, cracked from the stone, and the egg could be enjoyed.
True, the vulture was immediately pushed away from the feast by the vultures, and he began to work on a new egg. This interesting behavior was later repeatedly noted in the experiment. They threw eggs to the vultures and waited to see what would happen. Noticing a delicacy, the bird immediately picked up a suitable stone, sometimes weighing up to 300 g. The vulture dragged it in its beak for tens of meters and threw it on the egg until it cracked.
One day, a vulture was given fake chicken eggs. He took one of them and began to throw it on the ground. Then he took the egg to a large rock and threw it against it! When this did not bring the desired result, the vulture began to desperately beat one egg against another.
Numerous observations have shown that birds tried to split any egg-shaped object with stones, even if it was huge in size or painted in unusual colors - green or red. But they didn’t pay any attention to the white cube. Scientists have also found that young vultures do not know how to break eggs and learn this from older birds.

Osprey fisherman

The osprey bird is an excellent fisherman. Seeing a fish, it quickly rushes into the water and plunges its long sharp claws into the body of the victim. And no matter how hard the fish tries to escape from the claws of the predator, it almost never succeeds. Some observers note that the bird holds the caught fish with its head in the direction of flight. Perhaps this is an accident, but it is more likely that the osprey tries to catch fish in such a way that it will be easier to carry later. Indeed, in this case, air resistance is less.

Conclusion based on student reports – the progressive development of the brain and leading sensory organs (vision, hearing) is associated with intense metabolism, high mobility and complex relationships with environmental conditions.
Now explain why birds have become widespread in all climatic zones. What are the reasons for bird migration? ( Warm-bloodedness allows birds not to be afraid of frost and remain active even at very low ambient temperatures. However, the lack of food in winter forces them to migrate to better feeding areas.)

Conquerors of the air

Speed, range, flight altitude of birds

Regarding the flight speed of birds, researchers have different opinions. It is greatly influenced by atmospheric phenomena, so when moving long distances, birds either fly faster, sometimes slower, or take long breaks to rest.

Having released a bird in some place, it is very difficult to say when it will fly to its “destination”, because it may not fly for the entire time of its absence.

Speed ​​calculated by simply dividing the distance by the bird's flight time is often an underestimate. At especially “critical” moments - when chasing prey or escaping from danger - birds can develop very high speeds, but, of course, they cannot withstand them for long.

Large falcons during betting - chasing a bird in the air - reach speeds of 280-360 km/h. The usual, “everyday” speeds of birds of average size are much less - 50-90 km/h.

Everything said above concerns flapping flight.

The speed of gliding flight is also difficult to measure. It is believed that the hobby glides at a speed of 150 km/h, the bearded vulture – 140, and the vulture – even 250 km/h.

The range of non-stop flights of birds has been discussed for a long time. Like speed, it is very difficult to measure. The falcon, released near Paris, was discovered a day later on the island of Malta, 1,400 km away. Whether he was delayed on the way or was flying all the time is unknown.

In general, birds stop along the way quite often, and their non-stop flights are short. This cannot be said about flying over water barriers, where birds have nowhere to sit. The record for non-stop flight distance belongs to waders - brown-winged plovers, which annually fly 3000 km over the ocean from Alaska to Hawaii and back.

Birds fly non-stop across the Gulf of Mexico (1300 km), the Mediterranean Sea (600-750 km), the North Sea (600 km), and the Black Sea (300 km). This means that the average non-stop flight distance of birds is about 1000 km.

As a rule, the flight altitude of birds does not reach 1000 m.

But some large predators, geese and ducks, can rise to much greater heights.

Flight speed of birds and insects (km/h)

In September 1973, an African vulture collided with a civilian aircraft at an altitude of 12,150 m above the Ivory Coast. Grif disabled one of the engines, but the plane landed safely. This is apparently an absolute record for bird flight altitude. Previously, a bearded vulture was recorded in the Himalayas at an altitude of 7900 m, migrating geese were recorded there at an altitude of 9500 m, and a mallard collided with a plane over Nevada at an altitude of 6900 m.

Bird speed

The fastest bird

The fastest bird in the world, not counting the extinct pterodactyls, is the peregrine falcon (Falco peregrinus). In short areas during hunting, it is capable of reaching speeds of up to 200 km/h. The vast majority of birds are not able to move faster than 90 km/h.

This does not mean that they are not capable of other records. For example, the black swift (Apus apus) can stay in the air for 2-4 years. During all this time, he sleeps, drinks, eats and even mates on the fly. A young swift that takes wing flies about 500,000 km before landing for the first time.

The black swift has a number of records from the world of birds.

The bird can stay in the air non-stop for 2-4 years, all this time it eats, drinks and mates, during which time it can fly 500,000 km. The black and needle-tailed swifts have the highest horizontal flight speed, reaching 120-180 km/h. The flight of the needle-tailed swift is so swift that, in addition to a quiet cry, the observer can also hear a peculiar buzzing sound - this is the sound of the bird cutting the air.

In some parts of its flight, the needle-tailed swift can reach speeds of up to 300 km/h.

The woodcock is considered the slowest flying bird. During mating games, this small brown bird, referred to in Dahl’s dictionary as a “krechtun,” is capable of staying in the air at a speed of 8 km/h.

The African ostrich is not capable of flight at all, but it runs in such a way that many flyers would envy.

In case of danger, it can accelerate to 72 km/h.

A bird capable of not only making long flights, but doing it incredibly quickly, was discovered by Swedish ornithologists.

In their opinion, such endurance can only be compared with that of an airplane. Maintaining a speed close to 100 km/h for more than 6,500 kilometers is no joke.

In May, biologists from Lund University attached special geolocators weighing only 1.1 grams to the backs of 10 male snipes (Gallinago media).

A year later, they caught three of them and extracted the collected data. It turned out that the birds travel from Sweden to Central Africa and back.

One of the individuals flew 6,800 kilometers in three and a half days, the second 6,170 kilometers in three days, and finally, the last one flew 4,620 kilometers in two days.

At the same time, the wind did not help the birds. Biologists analyzed data from satellites and found that there were no favorable winds along the great snipe’s flight path.

It is surprising that great snipes do not stop on their way, because their flight mostly lies over land. Typically, land birds sit down to rest and replenish their energy reserves (there are plenty of earthworms, insects and other invertebrates on the surface).

A bird can fly if its body weight is no more than 20 kg.

Some birds scatter before flying, such as bustards and chickens.

For example, in India, when determining the flight speed of a swift, it turned out to be one hundred and seventy miles per hour, in Mesopotamia - one hundred miles per hour. The flight speed of the European falcon was measured with a stopwatch at the moment of its dive, and the result was from one hundred sixty-five to one hundred eighty miles per hour.
But most scientists question these figures. One expert believes the homing pigeon holds the bird record, and it cannot reach speeds over 94.2 mph.

Here are some generally accepted figures regarding the flight speed of birds. The falcon can fly at speeds of sixty-five to seventy-five miles per hour.

Bird flight speed

Slightly inferior to it in speed are ducks and geese, which can reach speeds of sixty-five to seventy miles per hour.

The flight speed of the European swift reaches sixty to sixty-five miles per hour, approximately the same as that of the golden plover and mourning dove. Hummingbirds, which are considered very fast birds, reach speeds of up to fifty-five to sixty miles per hour.

The starling's flight speed is forty-five to fifty miles per hour. Sparrows usually fly at a speed of twenty-five miles per hour, although they can fly faster: forty-five to fifty miles per hour.
Crows usually fly at speeds of twenty to thirty miles per hour, although they can reach forty to fifty miles per hour.

The flight speed of a heron is thirty-five to forty miles per hour, and that of a pheasant is thirty-five to forty miles per hour. And, oddly enough, a wild turkey can do thirty to thirty-five miles an hour. The speed of a pigeon jay is twenty to thirty-five miles per hour.

Flight speed

There is hardly any issue related to bird migration that is so widely misconceived as the issue of flight speed. Most people's opinions about the speed at which birds fly are based on casual, short-term observations, and therefore it is usually greatly exaggerated.

Others compare the speed of birds flying with the speed of a car, train or plane. However, they will not find such speeds even among the fastest flyers known to us. For example, swifts fly at a speed of 40-50 m/sec (regardless of the wind), which corresponds to approximately 150-160 km/h. (Compare: the maximum speed of an express train is 39 m/sec, or 140 km/h.) This, of course, does not mean that birds cannot fly faster at all.

Swifts chasing each other reach speeds of up to 200 km/h, and a falcon rushes at its prey at a speed of 70 m/sec, i.e. 250 km/h. But these extreme speeds for very short periods of time are exceptions: they at best characterize the flight ability of some species, but they cannot be used to estimate flight speed during migrations when long-term effort is required.

During long migrations, not only flight ability is important, but also wind.

Depending on its direction and strength, the birds' speed can significantly decrease or increase. Particularly high flight speeds can only be explained by taking into account wind support. Thus, in the example above, the speed of English lapwings flying across the Atlantic Ocean, equal to approximately 70 km/h, increased to 150 km/h thanks to a tailwind, the speed of which reached 90 km/h. Taking into account the retarding or accelerating influence of the wind, it is possible to accurately measure the birds' own speed over short distances and, in accordance with this, calculate the true speed of flight.

For the first time such calculations were made by Thieneman on the Kursk Spit. Subsequently they were made by Meinertzhagen, Harrison, etc.

The figures given in the table give a clear idea of ​​the maximum flight speeds of birds.

In general, it is obviously equal to 40-80 km/h, with the speed of small songbirds approaching the lowest figures. Birds migrating at night seem to fly faster than those migrating during the day. The low speed of migration of raptors and other large birds is striking. The same bird species usually fly much slower in the nesting area than during migration, if these speeds can be compared at all.

No matter how small the flight speed of birds is usually, or rather no matter how small it may seem to us, it is quite sufficient for some species to reach their wintering grounds in a few days and nights. Moreover, at such a speed, provided there is a fair wind (as, for example, when lapwings fly over the ocean), many migratory birds could fly to the tropics within a few days or nights.

However, birds cannot maintain this flight speed for more than a few hours; they almost never fly for several days or nights in a row; as a rule, their flight is interrupted for a short rest or for longer stops; the latter give the flight as a whole the character of a leisurely “walk”. This is how long migrations occur.

When considering the average speeds of day or night flights of individual species accurately established by ringing, one must always keep in mind that they do not characterize the ability to fly and the speed developed during migration, but indicate only the duration of flight and the distance between the places of ringing and finds of ringed birds in terms of one day.

Numerous finds of ringed birds prove that birds quickly fly most of the way, and use the rest of the time to rest in places rich in food. This type of flight occurs most frequently.

A uniform distribution of load and rest is much less common.

For birds flying long distances, the average daily distance is approximately 150-200 km, while those flying not so far do not cover 100 km in the same time.

A flight duration of 2-3 or 3-4 months is consistent with these data. many species that winter in tropical and southern Africa. For example, the stork, which usually leaves Germany at the end of August, reaches its wintering grounds in South Africa only at the end of November or December. The same terms apply to the shrike. Swallows migrate faster - from September to early November.

How great, however, the individual differences are in this case can be seen in the example of 3 ringed coot redstarts, one of which covered 167 km daily, another 61 km and the third only 44 km, and these numbers decrease as the time period increases. for which they are calculated (6, 30 and 47 days). Based on these results, it can be concluded that daily speed is most consistent with true flight speed when it is calculated on the basis of overall performance over a short period of time.

This conclusion is best proven by the following examples of the flight speed of individual birds: a stork covered 610 km in 2 days, a black-headed warbler covered 2200 km in 10 days, a coot covered 1300 km in 7 days, another coot covered 525 km in 2 days, and a mallard covered 525 km in 5 days. days - 1600 km. These data can be contrasted with the daily speed of the song thrush - 40 km (calculated over 56 days of flight), the chaffinch - 17.4 km (calculated over 23 days of flight) and the sparrowhawk - 12.5 km (calculated over 30 days of flight).

Bird speed

These data are comparable to the above data for redstarts, whose average speeds are strongly influenced by long rest stops as the flight duration increases.

When assessing the daily route and speed of flight, another important factor must not be overlooked: any digital data can be calculated only for the ideal flight route, that is, for a straight line connecting the places of banding and the discovery of the banded bird.

In reality, the flight path is always longer, deviations from a straight line are often quite significant, and the work performed and speed are much higher than calculated. These errors are almost impossible to eliminate and therefore must be taken into account, especially on very long flights.

In addition, you should pay attention to when this data was received.

The fact is that during spring migration the indicators in many cases are significantly higher than during autumn migration. In isolated cases, it could be proven with confidence that the spring migration is twice as fast as the autumn one, for example, in the stork, godwit and shrike.

Stresemann (1944) accurately established that in the spring the migration of the shrike lasts approximately 60 days, and in the fall - about 100 days. On average, these birds fly about 200 km per day. However, they only fly at night for 10 hours.

at a speed of 50 km/h. After such a flight, they always rest, so that they cover a distance of 1000 km in 5 days: migration - 2 nights, sleep - 3 nights, feeding - 5 days.

A few more words about the maximum speeds and flight durations that characterize the capabilities of migratory birds: the turnstone, a small coastal bird ringed on Heligoland, was found after 25 hours.

in Northern France, 820 km to the south. Numerous small songbirds regularly fly in 12-15 hours. The Gulf of Mexico is 750-1000 km wide. According to Moreau (1938), some small falcons (Falco concolor and F. amurensis), as well as Asian bee-eaters (Merops persicus and M.

apiaster), wintering on the coast of South Africa, also fly at least 3000 km above the sea. The Hawaiian Islands serve as the wintering grounds for a number of northern shorebirds, which, migrating from the Aleutian Islands and Alaska, where their breeding grounds are located, are forced to fly 3,300 km over the open.

by sea. The golden plover, a particularly strong flyer, would take approximately 35 hours to cover this distance at a speed of about 90 km/h.

Higher speeds were observed in another species of plovers, flying from Nova Scotia to the northern tip of South America 3600 km above the sea. It seems almost incredible that one of the Japanese-breeding snipes will fly to winter in eastern Australia and must cover almost 5,000 km to reach their wintering grounds.

On the way, he probably does not rest at all, since he was never celebrated in other places.

Flying over water can be compared to flying over large deserts. Such a flight also undoubtedly takes place without interruption, for example, the flight over Western Sahara of small songbirds, wagtails and pipits, which requires 30-40 hours. continuous operation, if their speed of passage is considered to be approximately 50 km/h.

The world's most famous bird lives in Transcarpathia

Science seems to suggest that for the speed of my life there are no equals, not only among birds, but among all other animals.

“The built Sapsan develops speed up to 300 km/year,” says ornithologist Viktor Palinchak.

“He is respected not only among the birds, but also among the representatives of the created world.” The wingspan of this wing is about one and a half meters, although the body length does not exceed 50 cm. As with most birds, female peregrine falcons are significantly larger than males: weigh about 900 - 1500 g, the same as a male and smaller sizes and weight 450-800 g "

The peregrine falcon is protected by the state and is listed in the Red Book of Ukraine.

Speed ​​of migratory birds

In Transcarpathia, according to the ornithologist, you can see it high in the mountains. Here the birds nest and sing. “For nesting, peregrine falcons find places that are inaccessible to people and have open spaces for everyone to see,” says Mr. Victor.

- Most often they live in the valleys of the Girsky rivers, here they have the best places to live. In addition, the peregrine falcon is unique in both farmsteads with rich forests and treeless expanses. It is not uncommon for a peregrine falcon to occupy the already inhabited nests of other birds, crows, and crows. The old houses will be abi-yak: with several needles and feathers. If the nest is well established, then ten generations can live there (which rarely lasts long).

The next skin pair has 2-3 sockets “at the moisture level”, which serve as spare ones when the main one breaks down.

“Swan’s faithfulness” is also popular with peregrine falcons. Birds live all their lives with one pair. “The love games of these huts are enough to finish the tsikava,” it seems scientific. “When the birds start to shine, they perform acrobatic tricks near the floor and play with each other.”

Peregrines are small birds, so they often suffer from pigeons, jocks, hummers, thrushes, swallows, and also forest animals: hares, squirrels.

It is important to cry at night. “At the hour of bathing, the birds take up positions at the top (on trees, rocks, or fly in the sky). Having noticed the treasure, the peregrine falcon flies like an arrow to it, hunting them down with the help of strong wings or sharp pains. As a rule, one blow is enough and the victim does not survive.”

In addition, since the peregrine falcons are the most common, the stink is still visible at its brightest.

Birds easily focus on the victim, as they say, because they are in the great vicinity. “This may be due to the fact that the crystalline oozes with a special ring from the cystic plate, which is compressed by forceful muscles, changing the curvature of the crystalline.

“Besides, the eye of the peregrine falcon has two “hot flames,” and other birds’ flames can enlarge objects that are located in the great distance (like binoculars).”

According to scientists, the peregrine falcon population has now begun to revive.

A decline was expected in the last century when the application of pesticides to crops became fashionable. “The peregrine sani carefully carried the qiu otrutu. Because of this stench, they died en masse, and the females could not hatch eggs with chicks. And now the number of birds has increased dramatically, and their nests can be built in great places.”

Olga Biley, Green Transcarpathia

07.08.2013 14:38:49

The peregrine falcon is a strong and fast bird that has no equal among predators. The peregrine falcon has long been used in falconry.

The falcon's distribution range is significant: it lives throughout Europe, both on rocky coasts and in inhospitable mountainous areas. Bird report with video and photo

Squad- Predator birds

Family— Sokolinye

Genus/Species— Falco peregrinus

Basic data:

DIMENSIONS

Length: 40-50 cm.

Wingspan: 92-110 cm.

Weight: male 600-750 g, female 900-1300 g.

REPRODUCTION

Puberty: from 3 years.

Nesting period: March-May, depends on the region.

Masonry: once a year.

Clutch size: 2-4 eggs.

Hatching: 30-35 days.

Feeding chicks: 35-42 days.

LIFESTYLE

Habits: Peregrine falcons live in pairs.

Food: Mainly other birds.

Life expectancy: up to 20 years.

RELATED SPECIES

Subspecies differ in size.

The largest subspecies of the peregrine falcon live in the Arctic, the smallest - in deserts.

Peregrine falcon hunting. Video (00:02:03)

Falcon hunting

The peregrine falcon (see photo) is one of the most dexterous hunters among birds. For this reason, he has long been pursued by falconers who devastated the nests of the peregrine falcon.

As a result, its population declined sharply.

WHERE DOES IT LIVE?

The peregrine falcon's favorite hunting place is open areas, such as peat bogs, steppes and semi-deserts.

In Central Europe, the peregrine falcon inhabits mainly mountainous areas. It makes nests on steep rock walls in river valleys or in old quarries. In winter, the peregrine falcon settles near large bodies of water, where it hunts the birds that live there—gulls. The specific name of the peregrine falcon is translated from Latin as “wanderer” or “pilgrim.” The peregrine falcon can also be seen during its journey to and from its wintering grounds, near lakes and estuaries.

In Central Europe, only young peregrine falcons are migratory, while older ones are sedentary. Birds from the northern regions migrate long distances.

Peregrine falcon and man

Feathered predators such as the peregrine falcon are at the top of the food chain.

It was proven that along the food chain (insects - small birds - raptors), the toxic components of DDT and other pesticides accumulated in the peregrine falcon’s body, affecting its reproductive system (the proportion of fertilized eggs fell) and calcium metabolism (the eggshells became thinner and cracked).

This caused a decline in the peregrine falcon population. Measures taken in the 60-70s of the last century to preserve birds of prey and the ban on the use of DDT had a positive effect on its population.

The peregrine falcon has long been domesticated for use as a hunting bird in falconry. Not all birds of the falcon family can be taught to hunt certain types of animals.

For example, the kestrel got its name back when falcons were assessed only by whether they were suitable for hunting.

REPRODUCTION

Peregrine falcons mate for life.

As a rule, they nest on hard-to-reach rock ledges or rock ledges. The nest is quite spacious, it can accommodate parents and chicks, and it is reliably protected from predators.

Flight speed of some animals, km/h

These falcons do not build nests; on the ground they lay eggs in shallow holes scratched with their claws, and in the trees they occupy the nests of other birds. Females begin laying eggs at the end of March. Most often they lay 2-4 red-brown eggs with red dots.

Hatching begins only when all the eggs have been laid. Both parents take care of the chicks.

FOOD AND HUNTING

The peregrine falcon feeds mainly on birds.

In winter, these birds inhabit areas around river mouths and hunt mainly gulls and ducks. The peregrine falcon catches most of its victims in the air. Noticing the prey, it makes a sharp acceleration and, in a diving flight, rushes at the prey, grabbing it by the neck, crushing the cervical vertebrae. With small prey he flies to the nest, and kills large birds in the air and lowers them to the ground. The peregrine falcon eats about 100 g of food per day.

During the period of raising and feeding the chicks, its needs increase. The falcon's hunting territory ranges from 40 to 200 km2.

Peregrine falcons very rarely hunt mammals, however, even rabbits sometimes become their victims.

Peregrine Falcon Observations

The best time to observe the peregrine falcon is during nesting season.

At this time, the birds do not fly far from the nest. Falcons circle high in the sky, sometimes quickly flapping their wings, sometimes soaring in smooth flight. In size, peregrine falcons are somewhat larger than domestic pigeons. This bird is easily distinguished in flight by its strong body, long pointed wings and relatively short tail.

At other times, peregrine falcons can be observed near river mouths or other large bodies of water, where they hunt ducks and other birds. A definite sign of the presence of a peregrine falcon is alarming voices and rapid, unexpected takeoffs of birds frightened by this falcon.

GENERAL INFORMATION

Sung in Ukrainian and Russian songs, the real falcon, which is often also called the “peregrine falcon,” lives in many regions of the globe.

It can be found from the polar cliffs of Scandinavia and Taimyr in the north to the fjords of Tierra del Fuego in the south. Falcons make nests on the ledges of cliffs or in abandoned nests of ravens and eagles. They feed mainly on birds (waders, crows, gulls, mallards and ducks, less often - geese), which they catch on the fly. In pursuit of prey, a peregrine falcon can reach enormous speeds during a dive! The maximum recorded speed of a peregrine falcon at its peak is 389 km/h!

Not every plane flies at such speed! This record was recorded in 2005.

Human persecution and the excessive use of pesticides in agriculture have led to the fact that this beautiful bird has become rare or completely disappeared everywhere.

Only the peregrine falcons of the Arctic were lucky. In the North, the falcon is called the goose shepherd, and for good reason: wild geese willingly settle next to its nests. After all, on earth it doesn’t hurt anyone. But in the sky no one can withstand the insane attacks of falcons!

• During World War II, peregrine falcons were killed because they preyed on carrier pigeons that carried war messages.
• The male peregrine falcon is almost a third smaller than the female; in addition, he is distinguished by dark plumage on the top of his head, on the sides of which dark “whiskers” are clearly visible.
• This falcon has large eyes and keen vision. A peregrine falcon can recognize its prey even from a height of 300 meters.
• Peregrine falcons have long been used for hunting. Nowadays, falcon hunting is only a sport.
• The peregrine falcon is in danger of extinction. The population of these birds is steadily decreasing.

MATING FLIGHT OF THE PEREGIAN FALCON

In the first part of the mating flight, the peregrine falcon transfers prey to the female.

At this time, the female flies downwards with her ridge and takes prey from the claws of the male.

— Where does the peregrine falcon live permanently?
— Wintering places
— Nesting sites

WHERE DOES IT LIVE?

The distribution area is significant: from the Arctic to South Asia and Australia, from western Greenland to almost all of North America.

PROTECTION AND PRESERVATION

Pairs nesting in hazardous areas are protected. There are approximately 5,000 bred pairs living in Europe today.

Peregrine falcon. Video (00:02:23)

The peregrine falcon hunts with the speed of lightning: having spotted its prey while slowly soaring, it builds itself directly above it and quickly, at an almost vertical angle, falls on top of it.

A strong blow often causes the unfortunate victim's head to fall off. If she managed to stay on her shoulders, the bird of prey breaks the poor fellow’s neck with its beak or uses its sharp claws.

Falconry with a peregrine falcon. Video (00:03:22)

Falconry, birds of prey - in this video you can see how a hunter catches game with the help of a falcon, or rather, the falcon catches for its owner.

Peregrine falcon.

The fastest bird in the world. Video (00:03:53)

The fastest animal on Earth is the Peregrine falcon. In a dive, it reaches an incredible speed of 90 m/s (over 320 km/h). In 2005, a record was registered - a peregrine falcon diving at a speed of 389 km/h.

It falls on the victim from the sky and knocks it down with a blow of its clawed paws. The blow is so strong that the victim's head is often torn off.
The peregrine falcon is a large falcon and in its group it is second in size only to gyrfalcons. The dimensions of one wing are from 30 to 40 cm, the wingspan reaches 120 cm.

The total length of the bird is from 40 to 50 cm, its weight is up to 1200 g.
It is worth noting that the peregrine falcon also has the sharpest eyesight in the world.

Peregrine falcon attacks Labrador. Video (00:01:41)

A peregrine falcon attacks a Labrador when it wanted to approach its prey.

Falcon Peregrine, Speed ​​183 mph. Video (00:03:01)