How birds fly. Lesson "ecological groups of birds" Takeoff and landing of birds

Target: To acquaint students with the reasons for the diversity of birds.

Tasks:

students must learn to recognize environmental groups of birds,
know the reasons for the diversity of birds,
know the signs of birds of different ecological groups,
be able to find information from different sources,
be able to summarize the information received and draw conclusions
be able to work in groups.

Equipment:

stuffed animals or drawings of birds of different ecological groups,
electronic laboratory work (Laboratory workshop. Biology grades 6-11. Educational electronic edition.)

Lesson plan.

Organizing time.
Repetition of previous material.
Formulation of the problem.
Performing laboratory work.
Conclusion.

During the classes

1. Organizational moment.

2. Repetition of the previous material.

The sparrows fluttered onto the fence.
The cat hears the sparrow choir
Only she can’t get sparrows:
I was too lazy to learn how to fly!

V. Bezborodov

List the signs of the class of birds (as a result of a frontal survey, students should name the signs, write them down on the board)

Body covered with feathers
Forelimbs modified into wings
Beak without teeth
fast digestion
Lightweight skeleton (bone cavities)
warm-bloodedness
Special breathing (air sacs)
There is a keel

Conclusion: thanks to these adaptations, birds are able to fly.

Do all birds fly the same way?

(messages prepared by students):

flapping flight
Gliding flight
shaving flight

Reasons for this diversity?

(Living in different conditions, adaptation to them.)

Are there flightless birds? (most often students say:

Ostrich
Penguin)

By what signs can we determine the ability of a bird to fly?

Wings (shape, size)
Plumage (dense, loose)
The size and weight of the bird

3. Statement of the problem:

Do flightless birds fly?

If you study the signs of a bird, you can determine its ability to fly.

4. Performing laboratory work "Ecological groups of birds".

Based on the results of laboratory work, a table is filled in (work in groups):

Environmental group	Representatives	signs
Environmental group	Representatives	Description of the wings	Weight and body size	Description of plumage
Ground	Ostrich, bustard, little bustard, guinea fowl	Wings are not developed, without flight feathers,	Birds of medium or large size	The feather cover is loose.
marsh	Heron, stork, bittern	Well developed, large, wide.	Small, medium, large.	The feather cover is loose, a small amount of down feathers.
Waterfowl	Eider, swan, cormorant, great grebe, penguin, mallard, goose	Well developed.	Medium and large, but smaller than ground ones.	Penguins have small feathers. There are no down feathers. All feathers are hard, dense, lean on each other. Can lubricate with secretions of the coccygeal gland.
Air-water	Seagull, tern, petrel	Well developed, relatively large	small and medium	dense hard
Air-ground	Swift, swallow, nightjar	Relatively large and narrow.	small	dense soft
birds of the forest	Woodpecker, owl, capercaillie	Broad, well developed	Medium and small	Diverse (hard, soft, in owls - loose)

The ostrich is a land bird that is unable to fly.

The penguin belongs to aquatic birds, by all indications adapted to flight.

5. CONCLUSION: the penguin is able to “fly”, but in the aquatic environment.

6. Homework: reports of bird orders.

Penguins and ostriches. flightless birds

Goals: repeat the material covered about the internal and external structure of birds, eggs; continue to acquaint students with the structural features and adaptability to the habitat of birds of various orders; to teach to recognize the studied birds in nature, in drawings, tables; develop attentiveness, the ability to speak in front of an audience; to cultivate responsibility, initiative, mutual respect; generate interest in biology.

Equipment: textbook; multimedia projector; photographs of ostriches and penguins; tables and visual aids.

Lesson type: learning new material.

During the classes

Organizing time

II. Activation of knowledge.

1. Sparrows fluttered onto the fence.

The cat hears the sparrow choir
Only she can’t get sparrows:
I was too lazy to learn how to fly! (V. Bezborodov)

List the signs of the class of birds (as a result of a frontal survey, students should name the signs, write them down on the board)

Body covered with feathers
Forelimbs modified into wings
Beak without teeth
fast digestion
Lightweight skeleton (bone cavities)
warm-bloodedness
Special breathing (air sacs)
There is a keel

Conclusion: thanks to these adaptations, birds are able to fly.

Do all birds fly the same way?

III. Learning new material

You already know that Birds are the most numerous class of vertebrates that live on land. In total there are about 8600 species of birds.

What is the name of the branch of zoology that studies birds? (Ornithology.)

Scientists combine all types of birds into three superorders: Penguins, Ostrich and Typical birds. Today's lesson is dedicated to Penguins and Ostriches.

Penguins are probably one of the most adorable creatures on earth. Until recently, penguins have been a big mystery to researchers. No one could tell which group of the bird family is closest to the penguins. This was due to their physiological features, such as wings turned into flippers, as well as a special shape of feathers, the same size and similar to scales. The first penguins appeared 70 million years ago, at the end of the dinosaur era. The oldest specimen of a penguin has been found in fossils 40 million years old. Modern penguins appeared in this form about two million years ago. All penguins lived and live in the southern hemisphere. The only exception is the Galapagos penguin found in Ecuador, which is also the only equatorial penguin. Penguins include 16 living species. In ancient times, there were about 36 species of penguins. Penguins are the only birds that walk standing up and can swim but not fly.

Does anyone know how penguins got their name? (Penguins had an outward resemblance to the wingless auk, it disappeared in the 19th century. The auk, moving on land, held its body almost vertically, and its wings served as flippers. Scientifically, it was called Pinguinus impennis (from English, pin- hairpin and wing - wing ).)

The first Europeans to see penguins were sailors from Vasco da Gama's crew. But they decided that in front of them were geese. English sailors, who also saw penguins, but at the end of the 16th century, mistook penguins for wingless auks and began to call them penguins, meaning auks. Soon the auks died out, and their name remained with the penguins.

Penguins are known for their exceptional adaptability to cold climates. This possibility is due to a thick layer of subcutaneous fat and three layers of feathers, which are evenly tiled adjacent to each other. For example, with a penguin weighing 38 kg, there are 17 kg of fat in his body. It is estimated that 87% of thermal insulation is provided by feathers, and the remaining 13% by fat.

- Why do you think? (Feathers act as fish scales, and they also keep the animal from getting wet and overcooled.)

Since their wings are not adapted for flight, they are used as fins and, together with the torpedo body shape, penguins can develop great speed. However, because of this, they slowly move along the ground, hobbling in different directions. The legs of these birds are shifted back, and the wings are transformed into a kind of flippers. Despite the fact that penguins move rather clumsily on land, they can reach speeds of up to 30 km / h in the water. In the water, penguins move with the help of flippers, and their webbed feet play the role of rudders. Penguins are not only good swimmers, but they are also pretty fast walkers. The speed does not exceed 1-2 km / h, but the distance that, for example, an emperor penguin can travel is up to 100 km without rest.

Penguins are unsurpassed divers in the world of birds. In the same breath, the emperor penguin can dive half a kilometer deep and stay under water for up to half an hour (usually this time is 6-7 minutes) in search of deep-sea myctophid fish. They feed mainly on small fish and krill, each catches for himself individually. Great amount food is consumed by the penguin colony during the mating season. In studies of Adélie penguins, it was found that adult birds make about 40 daily visits to the sea during the feeding period of chicks, and each time they bring with them about half a kilogram of food. So, for example, at Cape Crozer, a colony of 175,000 penguins brought almost 3,500 tons of fish ashore for chicks. And the largest rookery on Cape Adar consists of 250,000 birds.
Penguins are good parents. However, the role of mother and father is different from most birds, as the father is usually the one who spends most of the time taking care of the egg and heating it until the chick hatches. And the mothers go hunting to get food for both.
Since penguins are known to be residents of Antarctica, which is a very cold place, keeping the eggs warm is very important. Usually, fathers place the egg between their legs and cover it with their belly, which gives the egg the warmth it needs and keeps it warm. Fathers usually crowd together so that they themselves would not be cold. Although penguins live near the ocean, they drink fresh water. They have a special gland behind their beaks that is capable of filtering salt water. They also eat snow and ice as they contain fresh water. Penguins are surrounded by many predators. Some of their main opponents are dolphins, killer whales, so penguins are very careful. Another interesting fact about penguins is that they use sign language to communicate. They shake their heads or flap their wings to communicate.
Interesting facts from the life of penguins

The emperor penguin is the largest living penguin. His height is up to 117 cm, and his weight is up to 46 kg. While incubating eggs, he can starve for up to 9 weeks and endure cold up to -60 ° C.
The smallest living penguin is the little penguin. He weighs only 1 kg, and his height is 30-45 cm.
The Patagonian penguin is able to swim 2-3 weeks and cover
distance up to 1500 km.
The rarest of the Penguins is the magnificent penguin. Total
there are no more than 5 thousand birds of this species, and this number
constantly decreasing.
Tufted crested penguin can move its crest
The most common species in Antarctica is the Adélie penguin.
The number of these penguins is about 3 million pairs of birds.

Now let's talk about the Ostrich. These very remarkable animals are the largest modern birds. They live in Africa, Australia and South America. Ostriches cannot fly.

- Why do you think?

(The structure of the wings does not allow the bird to fly.)

The contour feathers of ostriches are feathered: they are devoid of hooks, and the beards do not form closed webs. Also, the small sternum of an ostrich does not have a keel. But the long, strong, callused legs of ostriches allow them to run fast, birds can reach speeds of up to 70 km / h.

- Ostriches have a small head on a long neck. Why does an ostrich have a long neck?

(To see the surroundings well. Helps with catching insects.)

The food of ostriches is insects, small vertebrate seeds of plants. There are several types of ostriches: African ostriches, Australian emus, American rhea, cassowaries and kiwi.

African ostrich(Struthio camelus) holds three records! It is the largest, fastest-running bird that lays the largest eggs. The weight of an ostrich reaches 160 kg with growth up to 2.75 meters. Males are heavier and taller than females. The most interesting thing is that ostriches are not the largest birds, if you consider extinct birds. The giant moa (Dinornis robustus), exterminated by the Maori tribe in New Zealand, reached a height of 3 meters and weighed 250 kg.

The ostrich is the only bird that has only 2 toes on its paws. The larger nail resembles a beak. There is no nail on the second finger. It is believed that the small number of fingers helps the ostrich run so fast. An ostrich can reach a running speed of 70 km/h. He is able to run without stopping 20 kilometers in 15-20 minutes. At full speed, the stride length of an ostrich is 5 meters! The paws of an ostrich are so strong that it can kill a person with a blow. As a defense, a person can only fall to the ground, but in this case he is threatened by a strong bird's beak. By the way, an ostrich can run at the speed of an adult ostrich already at the age of 1 month.

Ostriches can't fly. They use their wings during marriage ceremonies and to protect their children, since the wingspan of an ostrich reaches 2 meters.

Ostriches swallow stones and use them to improve digestion. About 1 percent of a bird's mass is made up of ingested stones. It's the same as if a person swallowed and carried up to a kilogram of rubble. An adult ostrich eats up to 7 kg of food per day. Moreover, ostriches are omnivorous - they eat plants and animals with the same taste - lizards, chicks, turtles and insects. The length of the digestive tract of an ostrich reaches 14 meters.

The eggs of other birds seem to us very fragile and tender. But eggs African ostrich withstand a mass pressure of 120 kg. These are the largest eggs among all animals - the egg weight is 1.5-2 kg, of which the shell weighs up to 300 grams. This is equivalent to 36 chicken eggs. Crocodiles, even with a mass of a ton, lay eggs no larger than goose. No wonder African bushmen use ostrich eggshells for storage. drinking water and as vessels.

Most of the day, ostrich eggs are incubated by males, and at once from many females from the flock. However, the distribution of eggs is carried out by the main female - she lays her own in the center, the eggs of other females along the edges. Once in Kenya, a clutch of ostriches was found, consisting of 78 eggs, of which only 21 were incubated. Such extravagance has a deep biological meaning: numerous predators first of all pick up eggs scattered around the nest, without touching those that lie in its center.

Cooking scrambled eggs from 1 ostrich egg can be equated to 25 chicken eggs.

In nature, ostriches live up to 30 years, in captivity - up to 70.

And now listen to the reports of your comrades about other types of Ostrich.

Nandu

Nandas live in South America. Nandu growth is up to 170 cm. Nandu live in packs, in September - December, the male takes 2-4 females out of the pack. Nandu courtship is peculiar. Males fluff up their feathers, wave their inflated neck at the female and make sounds similar to “nan-du!” The male himself prepares a nest in the form of a hole covered with grass. One female lays 10-15 eggs in the nest. Usually there are about 20 eggs in the nest, but sometimes there are up to 80. When the eggs are laid, the male rolls them out with his beak and hatches himself next to the nest. In nandu, only males incubate eggs: at night and in the morning, covering them with their bodies and wings. Hatching lasts 40 days, but the chicks do not hatch in one day. It happens that the last chicks die, because. the male has already left with other chicks. At the slightest danger, a caring father hides the kids under the wings. By the way, the ostrich needs wings for braking on the run and sharp turns. Nandu runs away from enemies not in a straight line, but in zigzags. So it's easier to break away. Six months later, striped nandu chicks become parents, and after 2-3 years they change their plumage. The color of the nandu is gray. The head, thighs and neck are covered with feathers (African ostriches do not).

Cassowaries

There are 3 types of cassowaries. These birds live in the rainforests of Australia, New Guinea and nearby islands. The cassowary is related to the emu. These birds live alone, not in the steppes, but in dense forests. Cassowaries have black plumage and a high horn crest on their heads. Their neck is tricolor: red, yellow, blue. With his helmet, the bird pushes the thickets of plants. Cassowaries feed on small animals, fish, and fallen fruits. The male incubates the eggs (there are 3-8 of them). Striped chicks. Unlike the nandu, the kuzuar has one female. Cassowaries are solitary, very quarrelsome. These are quite aggressive birds, they have quite aggressive birds on their middle fingers, they have a formidable weapon on their middle fingers - 10 cm claws. Often the birds fight among themselves. The cassowary is able to jump 1.5 m from a place. The Papuans make daggers from the bones of birds, their wing bones are needles. In New Guinea, young cassowaries are caught and tamed to be sold to zoos.

Emu

These birds live in the scrubby sandy deserts and steppes of Australia and Tasmania. Their food is fruits, seeds and small animals. Emu height reaches 1.5-1.8 m, weight 45-54 kg. The legs of the bird are very strong, three-toed. Emu is armed with a long sharp claw on the inner finger. Male and female emus are very similar and difficult to tell apart. In late September - October, the mating season begins. In January-February, the female leaves the male after laying 10 or more eggs. The female does not take care of the chicks, this is the responsibility of the male. The male emu incubates the chicks for 53 to 66 days. Hatching is not easy, the male eats almost nothing, in addition, the first and last days the period of incubation, he does not get up from the nest at all. Emus feed on fruits, berries and seeds that have fallen from trees. Before hatching the eggs, the male weighs 50-55 kg, at the end, he loses up to 16 kg in weight. After the 400-gram chicks hatch, the father takes care of them tenderly.

Kiwi

These smallest ostriches are found only in New Zealand. The birds got their name because of the sounds made by males. By the way, the female kiwi is much larger than the male, her beak is also much longer. For the first time Europeans met kiwi in 1811. Brown kiwis live in large families, but other kiwis are solitary or live in pairs. Kiwi is small (50-80 cm), it is similar in size to a chicken, but kiwi eggs are 6 times larger than chicken ones. Therefore, kiwis lay only one egg per year, but brown kiwis are capable of laying 4 eggs per year. Eggs are so big because they are 60-65% yolk. After three 3 months, chicks hatch from eggs, they grow rapidly, become independent after 3 weeks of life. Kiwi chicks peck the egg shell from the inside not with their beak, but with their feet. The body of the kiwi is covered with hairy feathers that look like fur. Kiwi wings are tiny, with a claw at the end of the wing. These birds feed mainly on invertebrates, but also eat berries, mushrooms, crayfish and frogs. Kiwis can live 30-40 years. The kiwi, the only bird in the world, has nostrils at the tip of its beak. This small bird has a good sense of smell.

I.Y. Consolidation.

Compare African, American and Cassowary ostriches? What unites them?

What is the difference?

Y. Homework

§ 27,28 (before Anseriformes). Answer the questions at the end of the paragraph. Prepare a message "The ostrich is the largest bird on the planet", poems, riddles about penguins and ostriches, Interesting Facts from the life of birds (optional).

Birds that can't fly are just as strange as animals that can't walk or fish that can't swim. Why, then, do these creatures need wings if they cannot lift them into the air? Nevertheless, on our planet there are whole detachments of such creatures. Some live in the sultry African savannah, others live on the icy Antarctic shores, and still others live on the islands of New Zealand.

Foreword

If we compare all types of birds that exist on our planet, then flightless birds occupy an insignificant part compared to flyers. Why is that? The thing is that the ability to fly helps them survive in the wild. Wings not only save birds from but also make it possible to get their own food. So, in search of food, birds are able to travel great distances, and this is much more convenient than scouring the ground in search of food. In addition, flyers can build their nests to raise their offspring at a considerable height, so that a dangerous enemy cannot reach the chicks. It turns out that it is much easier for birds that can fly to survive in a cruel world called "wildlife". This ability helped them become the second largest class of vertebrates. So, for example, scientists have 8500 various kinds birds, but there are only 4000 species of mammals. If flying is such an important way for birds to survive, then why don't some of them have this skill? How did flightless birds adapt to survive? We will analyze examples below. Scientists believe that earlier these birds also knew how to fly, but in the course of evolution they lost this ability. Well, let's look at what such strange creatures are.

Flightless birds: list

Flightless Birds: Penguins

These creatures are excellent swimmers and divers. They are found only in the southern hemisphere of our planet. Most of them live in Antarctica, however certain types can survive in temperate and even tropical climates. Some representatives of penguins spend up to 75% of their lives in water. These flightless birds can stay underwater thanks to their heavy, hard bones, which act as ballast, much like a heavy belt for a diver. Penguin wings have evolved into fins. They help control movement in the aquatic environment at speeds up to 15 miles per hour. These birds have a streamlined body, paddle-shaped legs, an insulating layer of fat, and waterproof feathers. All these properties allow the penguin to feel comfortable even in icy water. To keep warm, they have very stiff and very densely spaced feathers that provide waterproofing. Another property that allows you to survive in wild nature, is the unique white and black coloration of the birds in question. It makes the penguin invisible to predators both from below and from above. These birds live in colonies reaching the number of several thousand individuals. Penguins are the most numerous representatives of "non-flyers". So, annually up to 24 million of these creatures visit the coast of Antarctica.

ostriches

African ostriches are the largest birds on our planet. Their height can reach 2.7 meters, and weight - 160 kg. These flightless birds feed on grass, tree shoots and shrubs, do not disdain insects and small vertebrates. In nature, the creatures in question live in small groups - one male and several females. Ostriches have very sharp eyesight and excellent hearing. They are excellent runners. In case of danger, an ostrich can reach speeds of up to 70 km / h. In addition, he is an excellent fighter, his two-toed paws are a serious weapon. Judge for yourself: for one centimeter of the body with this bird, there is a force of 50 kg. Except high speed and excellent fighting qualities, the ostrich is distinguished by the ability to disguise itself well. In case of danger, it lies down and presses its neck and head to the ground, as a result it is difficult to distinguish it from an ordinary bush. As you can see, this representative of the “non-flyers” has perfectly adapted to survive in the wild.

Nandu-shaped

These flightless birds are common in South America: Argentina, Brazil, Bolivia, Uruguay and Paraguay. They inhabit the pampas (open spaces, steppes), covered with herbs and shrubs. An adult individual reaches a length of 140 cm, its weight is 20-25 kg. In appearance and lifestyle, the nandu resembles an ostrich, but scientists believe that these are completely different species. In nature, these birds live in groups of up to 30 individuals. In case of danger, an adult rhea can reach speeds of up to 60 km / h. Among natural predators capable of preying on adults are jaguars and cougars. But the young are suffering from the attacks of wild dogs. In addition, armadillos love to destroy the nests of these birds.

cassowaries

These flightless birds have much in common with ostriches, but their main difference is their three-toed paw. They are found in Australia and New Guinea. There are only two families in this detachment: Emu and Cassowaries. The latter reach 170 cm in length, their weight is 80 kg. They are characterized by a laterally compressed beak and a horn-like "helmet" on the head. Unlike ostriches and nandu, cassowaries prefer to live in forest thickets. They feed on fallen trees and small animals. Otherwise, the representatives of this detachment are similar to their close relatives - ostriches.

kiwifruit

Representatives of this species are nocturnal, live in the dense forests of New Zealand. During the day, kiwis hide in bushes and dense thickets of the forest, and at night they wander in search of food, which they find thanks to their well-developed sense of smell. They feed on worms and other invertebrates, which are pulled out of the damp soil. With help long beak these birds not only get food, but also make small depressions in the forest floor, in which they hide themselves.

Tristan Shepherd

It is the smallest flightless bird on earth. Now this species preserved only on the island of Impenetrable (it is free from people and predators) of the Tristan da Cunha archipelago. Previously, these birds were found in abundance on all nearby islands, but the cats brought by the white man completely destroyed this species on them. Shepherd prefers open meadows and fern thickets. It feeds on moths, earthworms, seeds and berries.

kakapo parrot

This bird is listed in the Red Book. She cannot fly, but she can glide from high ground to the ground. Despite the presence of full-fledged wings, the kakapo has weak muscles and heavy bones without air cavities. The bird is nocturnal and feeds on fern leaves, mosses, berries and mushrooms.

Extinct flightless birds

The most famous extinct “non-flyers” today are the wingless auk, and the first of them belonged to the Chistikov family. The length of her body was 70 cm. The wings were quite small, but well adapted for rowing under water. The bird was completely exterminated in the 19th century. Dodo, or Mauritian dodo, is an extinct flightless bird that inhabited the Mauritius islands in the Indian Ocean. It was completely exterminated by a white man and imported cats during the expansion of these lands.

Conclusion

So we looked at how flightless birds adapted to survive in the wild. The list of them, as you can see, is, in principle, quite diverse. Scientists believe that the first "non-flyers" appeared on the islands due to the fact that the food supply there was abundant, and there were no predators at all. Probably, this is precisely what explains the fact that individuals with both developed and underdeveloped wings, or even without them, survived equally under the mentioned conditions.

When I see birds soaring in the sky, I am always amazed: “How do they manage to stay in the air?”. After all, it is known that there is a force of gravity, which, in theory, should pull them down. Then what is their specialty?

What gives birds the ability to fly

Flying is a complex process. Of course, its main mechanism is the wings. They are arranged in birds in such a way that they are able to create lift, which, in turn, opposes the force of gravity. This force is generated when the wind hits the wing. But what do birds do if there is no wind?

They actively flap their wings, thereby creating a stream of air that lifts them above the ground. This is the most important stage of take-off, thanks to which, having flown up, the bird can soar without making a movement of the wings.

Of course, in addition to the wings, the musculature, the skeleton, and internal organs. To make it easier for the bird to rise into the air, it should be as light as possible. For this reason, her bones are filled with air. Also, a short intestine contributes to the rapid excretion of food, which facilitates the weight of the bird.

Why do birds fly in a wedge

If the reasons for the flight process can still be somehow guessed, then how to explain why most large birds fly in a wedge? It is amazing how synchronously and harmoniously they do it.

As it turned out, they choose such a construction in order to save energy. The first bird sets the air flow, and the subsequent ones, roughly speaking, take advantage of this - they pick up this flow and, thanks to synchronous movements, facilitate their flight.

Which birds don't fly

So, what does a bird need to fly:

Small body weight.
Developed muscles.
Wings and weight must be proportionate.

Not all birds possess all these qualities, and accordingly, they are deprived of the opportunity to fly. For example, penguins and ostriches do not fall under the last paragraph.

There are birds that have ceased to fly in the process of evolution due to the fact that the need has disappeared. They had no one to fly away from, there were no enemies in the surrounding nature. Now they are on the verge of extinction. Among them, for example, the kiwi bird.

Not all birds are able to fly - in the course of evolution, some have lost this ability. There are no flying species in the penguin order. In other groups, there are both flying and flightless ones, such as cormorants and parrots. Flightless birds are usually found on islands where there were no predators at one time. However, these days they can fall prey to dogs, mongooses and other predators. Very large birds, such as ostriches, also do not fly, but they run fast and defend themselves with strong legs.

How birds hover in the air

Usually, when a bird flaps its wings, it is moving forward. But some species, such as ospreys, sunbirds and kingfishers, can hang in the air.

Amazing in this respect are tiny hummingbirds that hover in front of a flower to drink nectar. At the same time, the bird, as it were, stands on its tail, and the wings quickly describe the eight in a horizontal plane. Hummingbirds are able to flap their wings for a very long time and with great frequency due to the fact that their pectoral muscles are huge in relation to body size.

When a bird flies forward, thrust is created only by lowering the wing, and lift is created by lowering and flapping. In other birds, lift occurs only when the wing moves down. When a hummingbird hovers, the torso and wings assume an almost vertical position, while the wings create lift, but not thrust.

Why do eagles soar?

Almost all birds soar from time to time, at least for a short time. Even hummingbirds can interrupt their buzzing flight to glide from flower to flower on fixed wings.

Birds as heavy as swans and bustards hover only when they land. small birds, as a rule, cannot efficiently glide through the air for any length of time. For many birds, soaring is not only an alternative to conventional flapping flight. Some species of hawks, as well as eagles, pelicans and storks, fly mainly by soaring - gliding upwards through the air. Having long wings compared to the body, these birds use ascending air currents (if the air is still, it is impossible to fly like that).

Updrafts exist near obstacles: in mountains, over hills, cliffs, etc. - here they are small, local. In addition, vast air masses rise when the reflected heat of the sun warms the air near the earth's surface. In such a flow, upward movement occurs in a wide spiral, while the rising air mass forms, as it were, a large dome. Thermal updraughts are usually absent over large bodies of water, and also at night. With few exceptions, soaring birds avoid places where sea meets land and do not fly in the dark.

In the updraft, the bird rises in circles to a great height, moves in the desired direction horizontally in the process of a smooth descent, reaches the next stream and rises again in circles. In this way, birds manage to cover a long distance in one day, eventually covering thousands of kilometers.

Birds of prey are excellent fliers. Among them are real aerial acrobats, such as the field harrier, which passes food to its partner in flight. The male and female differ in color, but both have a white tail.
The male throws the prey to the female, who turns upside down to catch it.

Why do seabirds fly so well?

The ascending air currents that provide birds soaring over land are absent over the sea. Therefore, birds such as albatrosses, petrels and boobies use a fundamentally different soaring technique.

Seabirds have a special gliding flight, using the power of horizontal winds and air jets reflected from the waves. Air currents near the surface of the water are slower than at altitude. The bird glides from a height almost to the water itself, then, due to the acceleration from the descent, soars up and turns sharply against the wind. The wind creates lift, carrying the bird up into a strip of more powerful air currents. Finally she turns around and glides down again.

Takeoff and landing of birds

For many birds, takeoff and landing is the most difficult maneuver. When taking off, the bird needs to be given a strong acceleration in order to get off the ground or a branch. For example, a small sparrow jumps up before taking off and begins to rapidly flap its wings. Heavier birds, in order to take off, take a run with spread wings. Waterfowl run across the water to gain speed before taking off.

The masters of the air, swifts and frigates, are not able to take off from the ground; for take-off, these birds fall from a height with their wings spread.

When landing, birds glide using their wings. During landing, their body turns vertically, the bird spreads its tail, and lowers its legs down, putting it forward. The role of the brake when landing in birds is performed by the wing, this is a bunch of feathers on the first finger of the wing.

To land, the bird needs to transform the forward movement and soften the impact on the ground. If the movement does not slow down enough, or if a gust of wind interferes, the bird may break.

When landing, the duck flies low over the water and splashes down, braking with its webbed feet and creating a reverse stroke with its wings to reduce speed. To take off from water or land, the bird creates a stream of air with its wings. So, the dive runs through the water, flapping its wings until it gains enough speed to break away from the surface.

Swallows in flight

Swallows in a graceful and long flight catch insects, touch the water in flight to drink. Here is a killer whale, common in Europe, North America, Asia and Africa. These birds rarely come down to the ground, mainly for nest material. This is done by males, whose tail is longer and the fork on it is deeper than that of females, whose task is to build a nest.

Swallows have very long seasonal flights: killer whales fly from Norway to South Africa, covering 11,000 km.

When chasing flying insects, swallows change the direction of flight almost all the time. Swallows on the fly not only eat, but also drink, opening their beaks very wide.