Tree-shrub birds. Methodological development "identifier of birds of the tree and shrub zone". Ecological groups of birds

According to modern ideas, the formation of birds was associated with an arboreal lifestyle, characteristic of Archeopteryx and, apparently, of all less specialized ancestral forms that have not yet been discovered. Most living species are confined to forests and bushes. However, paleontological data indicate that already in the Cretaceous period birds associated with water bodies appeared: Ichthyornis apparently ecologically resembled gulls or petrels, and Hesperornis led an aquatic lifestyle, like loons or grebes, and even lost the ability to fly. All this allows us to assume that from the moment the class of birds arose, its evolution followed a broad adaptive radiation: morphological and physiological characteristics specific to the class as a whole were developed, and at the same time more specific adaptations arose that made it possible to develop various habitats and various life niches.

These particular adaptations (idioadaptations) are very multifaceted (have a variety of adaptive significance) and represent morphophysiological, ecological and behavioral changes that provide (with respect to the conditions of a given habitat) the optimal nature of movement, nutrition, reproduction, protection from enemies and adverse weather influences. They determine the nature of flight and other movements characteristic of the species (walking, running, jumping, swimming, diving), the relationship between the sexes during reproduction, the shape and color of eggs, the size of the clutch, the level of physiological maturity of the chicks at hatching, the degree of their pubescence, the nature and pace of their postembryonic development, relationships between chicks and adult birds, the range of food used, methods of searching and capturing prey, attitude to the territory (sedentary, nomadic or migrant) and to individuals of their species (single, group or colonial nesting, solitary or flocking lifestyle), daily rhythm activity (Ilyichev V.D. et al., 1982). In other words, these adaptations determine all the specific features of a given species, separating it from others.

5.1. Adaptation of birds to living conditions

Biological groups of birds. According to the degree of physiological maturity of the chicks at the time of hatching, all bird species are divided into two biological groups: brood (mature hatching, or maturonate) and nestling (immature hatching, or immature). Some species occupy an intermediate position between these extreme groups.

Chicks of brood species hatch from the egg well-furred, sighted, with open external auditory canals (Fig. 5.1). Having dried, they leave the nest and roam with their parents, maintaining visual and sound contact with them. In many species, from the first days of life, the chicks feed themselves; an adult bird only leads the brood to feeding areas, protects the chicks, and warms them (all Anseriformes, Galliformes, Bustards, and many waders). In other species, adult birds feed the chicks for quite a long time, which gradually learn to find food (grebes, cranes, rails, some waders).

Chicks usually need only relatively short-term heating, as they have dense pubescence. In many species, fairly perfect thermoregulation is established already on the 1st-4th day after hatching. Relatively longer hind limbs than in adults facilitate the movement of chicks. In chickens, the skeleton of the wings grows rapidly and wing feathers quickly form, which allows the chicks to flutter already at the age of 5-8 days.

In case of danger, usually due to an alarm signal from the parents, the chicks hide; the cryptic coloring of the down makes them hardly noticeable against the background of the substrate. An adult bird often tries to divert a predator from a hidden brood: it runs, noisily flapping its wings, fights in place, etc. Constant communication of chicks with an adult bird and with each other in changing situations contributes to the rapid (in fact from the first days of life) complication of their behavior as as a result of the manifestation of innate reflexes, and through the development of conditioned reflexes and imitation of the behavior of an adult bird and peers. Chicks quickly learn to find and grab food, hide from danger and adverse weather conditions, navigate the terrain, etc.

Chicks of immature hatching species emerge from eggs naked (copepods, swifts, woodpeckers, some Coraciiformes and passerines) or very slightly pubescent (Coraciiformes, many passerines), with closed eyes and closed external auditory canals (Fig. 5.2). The chicks remain in the nest until they are almost adult size and fledge. They need regular heating (thermoregulation is established only at the time of departure from the nest) and feeding. At the moment of hatching, they react unambiguously to all irritations (noise, shaking of the nest, touch, etc.): they stretch their head and neck upward and open their beak wide (“asking for food”). Often brighter than in adults, sometimes with spots, the coloring of the mouth and tongue serves as an irritant that triggers the feeding instinct in parents.

In hollow-nesting chicks, fleshy growths in the corners of the mouth (whirlwinds, tits) and, in addition, a longer mandible (woodpeckers, hoopoes, starlings) increase the size of the pharynx, which makes it easier for the chick to capture food brought by adults. Many species have a fairly well-defined heel callus - a growth of keratinized skin on the underside of the intertarsal joint.

On the 4-6th day of life (somewhat later in hollow nesters), the chicks begin to see clearly (moving eyelids open the eye); At approximately the same time, the external auditory canals open. During this period, the chicks begin to analyze external stimuli: when their parents appear at the nest, they ask for food (if they are hungry), and in response to all sorts of other stimuli, they hide at the bottom of the nest. Then the plumage gradually begins to form and unfold; With some delay, thermoregulation is established and the duration of heating of the chicks by the parents is reduced.

With half-unfolded plumage, the behavior of the chicks becomes more complicated: when their parents arrive, they ask for food, when there are unusual stimuli (noise, shaking of the nest, etc.) they hide, and when there are particularly strong stimuli (sharp shaking of the nest, the appearance of a predator or person at the nest, etc. .) jump out of the nest and hide on the ground; this allows at least part of the brood to survive an attack by a predator. After the alarm stops, the chicks usually do not return to the nest, but, responding to the calling cries of the adults, gather somewhere together; adults continue to feed them and, if necessary, warm them.

Normal departure from the nest occurs when the chicks reach or almost reach the size of adults (their weight may even slightly exceed the weight of adults due to the accumulation of fat reserves); the main groups of feathers (including the flight feathers) have almost completed their growth (the opened webs of the contour feathers cover the entire body, the wings have formed, but the tail feathers are usually still very short). By the time of departure, full thermoregulation is established.

In most birds, fledged broods wander with their parents for 1-2 weeks (sometimes longer). Adults continue to feed the chicks, attract them to places where food is concentrated, warn them of danger, etc. It is during this period that the formation of a specific behavioral stereotype occurs based on the deployment of a complex of innate reflexes and the acquisition of individual experience by imitation of adults and peers. Thus, the acquisition of individual experience necessary for independent life, the use of “generational experience” (by imitation of adults) in brood species begins immediately after hatching, and in nestling species only in the second half of their stay in the nest and mainly after leaving it.

In birds of prey, the chicks upon hatching are covered with down, sighted, but require heating for a long time and leave the nest only after being fully feathered and acquiring the ability to fly. The same can be said about owls, whose chicks hatch with their eyes closed, but rather well furred. In storks, sighted and pubescent chicks upon hatching remain in the nest until they acquire the ability to fly, and heron chicks that hatch naked or slightly pubescent, with half-closed eyes, half-fledged, often, especially in danger, leave the nest and hide nearby. These examples show that there is no clear break between brood and chick groups: there are species with a more or less intermediate type of development.

Ecological groups of birds. In the process of evolution, birds have developed a large number of different forms adapted to life in a wide variety of conditions. Some birds inhabited forests and bushes, where they developed the appropriate paw structure for living among the branches. Other forms adapted to life on the water, and their further development followed the path of specialization in swimming and diving. Some forms, to a greater extent than others, have mastered the air environment and spend most of their lives on the wings, revealing various adaptations in the wing structure that ensure the soaring flight of large predators, the rapid active flight of swifts and swallows. Steppes and deserts are inhabited by a number of species that have adapted to walking and running on solid ground.

Based on the preferred types of landscapes and movement patterns, the following main ecological groups of birds are distinguished: arboreal-shrub, terrestrial-arboreal, terrestrial, semi-aquatic, aquatic, and flying-hunting. It should be noted that, as with any other attempts at biological classifications, a fairly large number of species occupy an intermediate position and their assignment to one group or another turns out to be quite arbitrary, therefore the boundaries between the identified groups are unclear and very arbitrary.

Tree and bush birds They feed mainly in the crowns of trees and bushes, in thickets of reeds and other emergent plants, where they nest. Nests vary in complexity, in some species they are very skillfully woven, warm and durable; Some species nest in hollows. The bulk of the species in this group are made up of various families of passerines, orioles, some corvids, tits, warblers and many others. This also includes cuckoos and woodpeckers.

While collecting food, birds jump from branch to branch, sometimes helping by flapping their wings. Small birds of this group, clinging to uneven bark with strong fingers with sharp claws, can move along vertical tree trunks (tits, nuthatches, pikas). In real woodpeckers, the structure of the paws changes: two fingers are directed forward, two - back; all fingers bear powerful, strongly curved, sharp claws that reliably cling to any irregularities in the bark. The tail, made of strong, rigid tail feathers, is pressed against the trunk and serves as an additional support point (Fig. 5.3). These features allow woodpeckers not only to move along vertical trunks, but also to chisel.

Species of this group feed on various insects and other invertebrates, fruits, berries and seeds; some species eat buds, anthers of flowers, and drink nectar. Some larger species (corvids, woodpeckers) simultaneously eat the eggs and chicks of other birds. The shape of the beak and tongue corresponds to the nature of the food specialization. In predominantly insectivorous species, an elongated thin beak allows (like tweezers) to pull prey out of cracks in the bark and from the axils of leaves. Flycatchers, shrikes and others often lie in wait for prey, sitting calmly on a branch and, taking off, catching an insect that flies close. Such fishing is facilitated by a slightly widened, flattened beak (flycatchers). Seed-eating species with a strong conical beak are able to split or gnaw the dense shells of seeds (the grosbeak gnaws the pits of cherries and olives). With the sharp, strongly intersecting ends of their powerful beaks, crossbills deftly open the scales of conifer cones, taking out seeds; the sharp keratinizing end of the tongue cuts off the wings of the seeds.

Woodpeckers, having a powerful chisel-shaped beak, chisel bark and wood, opening the passages of insects and their larvae. The long tongue can extend from the mouth almost to the length of the beak, has spines directed backwards at the end and is covered with sticky saliva. The woodpecker inserts its tongue into the open passage and pulls out the prey with its tongue.

Ground-arboreal birds They are close to the first group in appearance and differ only in that they equally successfully collect food both in the crowns and on the ground. Some species build nests in the crowns of trees and shrubs, nest in hollows, or make a nest on the ground. This includes some of the grouse (grouse, grouse, hazel grouse) (Fig. 5.4), many corvids, thrushes, wrens, starlings, many weavers, finches, and buntings. This group contains both insectivorous species and omnivores, feeding on various invertebrates (and some, such as corvids, and vertebrates), berries, seeds, and vegetative parts of plants. Variations in beak structure correspond to food specialization and are similar to many beak variations in the first group. In the crowns they jump from branch to branch; on the ground, small species usually move in jumps, and larger species (grouse, pigeons, parrots) - in steps. Species of similar sizes can also differ in their gait: for example, blackbirds and magpies jump on the ground, while starlings, jackdaws, rooks, and crows walk. Some species, looking for food, rake the top layer of litter (grouse, blackbirds).

N land birds a collective group that unites birds with varying degrees of adaptation to a terrestrial lifestyle. Quite a few species retain the appearance of arboreal-shrub or terrestrial-arboreal birds, but feed almost exclusively on the ground where they build a nest, but for rest and in case of danger they willingly perch on trees and bushes. The terrestrial lifestyle of these species is ensured primarily by behavioral characteristics. Morphological adaptations are not clearly expressed: the claws are usually somewhat less curved, the strong hind limbs of many species allow them to rake the litter in search of food, and in some species a protective coloration develops (Fig. 5.5). They walk and run on the ground, rather than jumping. They feed on various insects and other invertebrates, collecting them on the ground and grass (by jumping and flying, some also catch flying insects), and eat seeds and berries. These species include some passerines (larks, pipits, wagtails, stonechat), and hoopoe. More distinct adaptations to a terrestrial lifestyle are characteristic of most chickens. The strong hind limbs of these species are relatively short. Strong short fingers end in blunt claws; the rear (first) finger is usually small or completely reduced. All these land birds walk and run well. When in danger, they run away or fly away; many species go into hiding. The food is predominantly plant-based (vegetative parts of plants, seeds, berries, tubers), but they readily, and sometimes in large quantities, eat a variety of invertebrates and small lizards. The beaks of all species are strong, varying in length, usually with a pointed end, ensuring the capture of both animal and plant food.

This also includes a number of long-legged species that in appearance resemble semi-aquatic birds: some crane-like birds (demoiselle crane) and the secretary bird of the diurnal birds of prey. Elongated limbs (especially the tarsus) with strong fingers allow these birds to easily run through tall grass, chasing reptiles (lizards, snakes) and large insects. Prey is grabbed with the beak (cranes) or paws (secretary), then killed with the beak.

Waterbirds inhabit a variety of damp habitats: overgrown and open banks of water bodies, extensive swamps. This includes all ankle-bearing, or stork-like, many crane- and chariformes.

Most species of this group are characterized by elongated limbs (the tarsus and tibia are elongated, the lower part of the latter is usually not feathered) with long thin fingers (all four in herons, many rails; in the rest, the hind finger is small or absent), sometimes connected at the base by a rudimentary swimming membrane (Fig. 5.6). This makes it possible to walk and run through thick grass and shallow waters without wetting the feathers and without falling into muddy muddy ground; some species (small rails) easily run on floating aquatic vegetation. As a rule, the lengthening of the limbs is accompanied by a lengthening of the neck: the bird reaches the ground with its beak, only slightly tilting the body. In some species, the body is clearly compressed laterally, allowing it to slide between stems in dense thickets. A carelessly built nest is located on the ground, on creases of reeds, sometimes in trees (herons, storks, ibises).

A very wide range of nutrition for this group is provided by various adaptations. Cranes feed mainly on a variety of plant foods (seedlings, rhizomes and bulbs, young shoots, seeds, berries), and along the way they catch (sometimes in large quantities) various invertebrates, amphibians, and lizards. They have a strong, elongated beak with a pointed apex. Some rails also use plant food; these species have a powerful and relatively short beak. Other species of waterbirds are predominantly carnivorous. Herons and storks consume a variety of animal foods (invertebrates, fish, amphibians).

Water birds - a very diverse group of birds that forage for food by swimming and diving; some feed on land. They inhabit the coasts of the seas and various continental bodies of water. This includes grebes, anseriformes, or lamellar-billed animals, and some rails (coots).

In species of this group, the body is usually flattened in the dorso-ventral direction, which provides greater stability on the water (Fig. 5.7). The plumage is tight-fitting and successfully resists getting wet. Well-developed down and downy parts of the webs of contour feathers improve thermal insulation; This is also facilitated by the strong development of subcutaneous fat deposits. All this allows you to swim and dive in cold water for a long time. The hind limbs are relatively short; three fingers pointing forward are connected by a well-developed swimming membrane. Only grebes, rails (coots) and wading sandpipers do not have a swimming membrane, but each of the three forward-pointing toes is equipped with elastic and strong horny edges, which also noticeably increase the paddle surface of the paw. In good diving species, the sternum usually lengthens and the number of ribs increases (improving the protection of internal organs from external pressure), the pelvis narrows, and in some good divers the legs move back (grebes).

Aquatic birds usually nest near water bodies, more often on the ground, less often on reed creases and trees. Grebes and coots build floating nests in thickets of emergent vegetation.

The vast majority of species in this group are carnivorous: they feed on fish and various aquatic invertebrates. When swimming, phalaropes use their thin, pincer-shaped beaks to peck various small invertebrates from the surface of the water and leaves of emergent plants. Coots of moderate length, which feed mainly on plant foods, have a strong beak that makes it possible to tear off pieces of plants and grab aquatic animals. In Anseriformes, at the end of the widened beak there is a well-developed thickened area - the nail, which forms a small hook; horny plates along the edges of the beak and mandible and on the sides of the fleshy tongue form a filtering apparatus that releases water and silt, but retains food objects in the oral cavity: various small animals and seeds. A strong nail allows you to tear off attached mollusks, parts of plants, etc. In ducks that feed on small animals, especially shovelers, the plates of the filter apparatus are thin, long, and very dense. In eiders, which feed mainly on relatively large attached mollusks, and geese, which feed largely on land on land plants, a strong nail at the end of the beak and rough, more sparsely seated plates along its edges make it easy to tear off and crush mollusk shells and pluck fresh greens. In mergansers, these plates turn into teeth, making it easier to hold the fish.

Of the passerine birds, dippers should be included in this group. They feed on insects, their larvae and other invertebrates, collecting them on the banks and bottom of rivers and streams, and retain the typical appearance of passerines (only the plumage is somewhat denser, thick down is developed on the apteria, the wings and especially the tail are short). They cannot dive in still water.

Birds hunting in flight - a heterogeneous and diverse group, including representatives of many families whose close relatives are included in the previously described groups. More common in open landscapes.

Quite a few species in this group are associated with water. These are birds with long, narrow, pointed wings, possessing agile flight and usually capable of long soaring. The fingers are connected by a swimming membrane. Relax on the water or on the shore. The most common way of hunting is to fly at different heights above the water and quickly dive on prey (fish, large invertebrates) seen on the surface or in the upper layer of water. Due to the energy of the dive, birds can plunge into the water, at this moment grabbing prey with their beaks. This is how gulls, terns and phalaropes hunt. Seagulls often collect food by wandering in shallow waters and on land.

Many birds of prey (eagles, buzzards, kites) soar high in the air for hours, looking for prey, and then catch up with active flight, dive and grab them on the ground (and birds in the air). Unlike birds that hunt over water, their wings are somewhat shorter, but noticeably wider, with a blunt apex. The prey is grabbed by powerful paws armed with sharp claws, killed and torn apart by a strong beak with a sharp hook at the end. Osprey and many eagles feed mainly on large fish: they soar over bodies of water and, diving, grab prey that has risen to the surface with their paws.

Hawks use two methods of hunting: the predator sits in cover and suddenly rushes at the approaching prey, or it flies, often along the edges, and grabs the frightened prey in a quick throw. They are characterized by relatively short wings and a long tail, allowing them to pursue prey among branches. Having fast, maneuverable flight, falcons usually fly around their hunting area and, in a swift dive - dive - grab the prey they encounter in the air or on the ground. When looking out for prey on the ground, small falcons are capable of hovering in the air for a short time in a fluttering flight.

In addition to the main method of hunting - looking out for prey in flight and grabbing it in flight - many predators catch large insects while wandering on the ground, watch for rodents near burrows, and drag chicks from nests.

Owls search for their prey in flight or lie in wait, sitting in ambush, and catch them in a short throw, grabbing the victim with their paws. Unlike diurnal birds of prey, the main receptor for detecting and grasping prey in owls is not vision, but hearing. Nightjars, like owls, lead a crepuscular and nocturnal lifestyle; They feed mainly on large insects, which they catch in the air or, less commonly, peck in flight from the ground and branches. They also have silent, maneuverable flight; the plumage is soft, although not to the same extent as that of owls. Long sharp wings, rapid maneuverable flight, a small beak, but a very wide mouth opening, bordered with stiff bristles at the corners, are characteristics of swifts and swallows that are ecologically close to them. Swallows catch prey only in flight; They do not use other methods of hunting. They feed on small insects. Swallows are able to peck sitting insects from branches and leaves in flight. Only in flight do bee-eaters catch large flying insects. A rather long beak, thinning towards the end, slightly curved downwards, the absence of long bristles in the corners of the mouth - these features of bee-eaters are associated with the larger size of their prey compared to the food items of swallows and swifts.

This classification is schematic, but it gives a fairly complete picture of the ecological diversity of the class of birds. They have mastered almost all niches suitable for life: only sea depths over 50-60 m and the thickness of the soil remain inaccessible to them (although individual forks dig nesting holes).

Within each ecological group, a large diversity is revealed in terms of biotopic location, nesting sites and types of nests, sets of food used and methods of obtaining it, which correlates with many species characteristics - the proportions of the limbs and the nature of movement, the properties of plumage, the shape of the beak and tongue, structural details digestive system, structure of receptors, etc.

Despite the obvious ecological diversity, the general appearance of birds, as well as their morphophysiological characteristics, varies within relatively small limits. The diversity of appearance, size and morphophysiological characteristics among mammals is much more pronounced. This greater morphophysiological homogeneity of birds, compared to mammals, is apparently due to adaptation to flight, which created severe restrictions on variations in body shape and its functioning systems.

Trophic groups of birds. The food spectrum of the bird class is quite wide and includes a variety of plant and animal foods. Based on the variety of food used, birds are usually divided into three groups: polyphagous, stenophagous and intermediate.

Polyphages(omnivores) feed on a wide variety of plant and animal foods. Approximately 1/3 of the families can be attributed to this group, and within each family, omnivory is more pronounced in larger species. Examples of the most typical polyphagous birds are large corvids (ravens, crows, etc.), large gulls, and cranes.

Stenophages - species that consume uniform food and use uniform methods of catching prey. Stenophagy is relatively rare among birds. Stenophages include swifts and many nightjars, which feed only on flying insects, and swallows, which also catch insects in the air, but can also peck them from plants in flight. This group also includes typical scavengers, as well as species that feed only on large fish, such as osprey. Stenophages also include crossbills, which feed mainly on the seeds of coniferous trees.

Intermediate The group consists of the majority of birds that use a fairly wide range of feeds for feeding. These are many passerines that feed on both various insects and seeds. Grebes feed on fish and a variety of large aquatic invertebrates; green parts of plants, berries, seeds and various invertebrates - galliformes.

The degree of food diversity varies among different species. For example, in loons and cormorants, aquatic invertebrates usually constitute only a small addition to the fish diet, while in many grebes they may even be the predominant food group.

Based on the composition of food, a number of ecological groups are also distinguished in the class of birds. Species that feed primarily on plant foods are called phytophages. Geese, swans, some ducks, and coots feed mainly on a variety of coastal and aquatic vegetation, simultaneously eating various aquatic animals. Green parts of plants, berries, seeds, buds, catkins - the basis of food for galliform birds. Many passerines feed primarily on seeds - weaver birds, finches (especially crossbills, grosbeaks, greenfinches), and larks. However, all phytophages, if possible, use a variety of animal foods to one degree or another; their consumption especially increases during the breeding season, since most of these birds feed their chicks mainly with animal feed.

Species that feed primarily on animal foods are called zoophages, although many of them eat plant foods, albeit to a small extent. Almost a third of living bird families are exclusively or predominantly insectivorous ( entomophages); Almost all birds use insects to one degree or another. Many aquatic and semi-aquatic species feed primarily on fish (ichthyophages), simultaneously eating aquatic invertebrates.

Many birds of prey and owls are myophages, those. feeds mainly on small rodents. Few birds of prey can be called ornithophages: hawks, falcons (peregrine falcon and hobby falcon), marsh harrier and some others feed mainly on birds.

TO herpetophagous(feed on amphibians and reptiles) include the snake eagle, secretary bird, and some large kingfishers. However, such a division by type of nutrition is largely arbitrary and schematic.

Changes in nutrition are typical for all groups. Typical ornithophages, for example, on occasion catch mammals, lizards and large insects.

Due to the seasonality of the availability of different types of food, many bird species experience seasonal changes in nutrition. The degree of variability is determined by the nature of food specialization.

Quite sharp differences in the quantity and degree of availability of various groups of food in different years cause changes in the nutritional spectrum of many birds from year to year. There are many known examples of such seasonal, geographic and annual variability in nutrition. It is well expressed even in stenophagous birds. The opposite feature is also characteristic of birds - when mass, easily accessible food appears, species that usually do not use it begin to feed on it. When puddles and small lakes dry out, the mollusks, tadpoles and fish fry remaining on the mud are picked up not only by crows and magpies, but also by pigeons, blackbirds, and shrikes. The number of birds increases sharply in places of mass reproduction of insects or mouse-like rodents, in orchards when cherries ripen, and on plantations when berries ripen. This ability to quickly find accumulations of food and use them determines the participation of birds in limiting and eliminating pest outbreaks.

Almost all birds experience, to one degree or another, an age-related change in food. In mature hatching chicks that feed themselves (Anseriformes, Galliformes, many waders), this age-related change in food is primarily due to the fact that, due to their small size and poorly developed methods of obtaining food, some of the food obtained by adults is simply not available to the chicks. As the chicks grow, these differences in nutrition gradually disappear.

Immature hatchlings eat what their parents bring to them. In many species, age-related variability in nutrition is well expressed, due to the selective supply of food by adult birds, which undoubtedly significantly accelerates the growth and increases the survival rate of chicks. Thus, great tits try to carry spiders to newly hatched chicks, sometimes squeezing only their “contents” into the chick’s open beak, and swallowing the “shell” themselves. After two or three days, parents begin to feed small larvae, caterpillars, butterflies with torn wings, aphids and other soft insects to the chicks, and they often feed the already grown, fledged chicks with beetles. The adult birds themselves eat at this time any insects available to them. Other passerines act in a similar manner. Only greenfinches and crossbills feed their chicks mainly with seeds.

Methods of obtaining food birds are not very diverse. The vast majority of species take prey with their beaks. In accordance with food specialization, the shape and relative sizes of the beak vary widely. Straight or curved, very long and thin beaks of waders and some passerines allow them to extract food from moist soil or narrow and deep shelters. The sharply conical beaks of many granivorous birds, powerful at the base, make it easier to grasp and chew seeds. The powerful beaks of birds of prey, owls, and partly shrikes, with a sharp “hook” varying in length on the beak, help to hold and tear food; beaks with numerous plates along the edges, allowing them to filter small prey, are characteristic of Anseriformes. Small beaks with a very large mouth opening and bristles at its corners in swifts, nightjars and swallows form a kind of “net” that makes it easier to catch small flying insects.

The shape of the tongue is no less diverse, which in many birds not only helps in swallowing a bolus of food, but is also involved in grasping and holding prey. Thus, the strongly protruding tongue of woodpeckers, usually equipped with sharp spikes at the end, allows one to feel the larva in the hollow passage and pull it out. The fleshy, mobile tongue of many seed-eating passerines, along with the ridges on the palate, makes it possible to conveniently place a seed or nut on the edge of the beak to crack the shell. With a movable tongue with a flattened, keratinized apex, the crossbills cut off the buds of coniferous seeds. Birds that catch fish and a variety of aquatic invertebrates have numerous sharp spines on their tongues directed toward the pharynx, making it easier to hold and swallow prey (grebes, mergansers). The fleshy and mobile tongue of anseriformes, bordered with plates, is involved in filtering food.

Daytime predators and owls grab prey, especially large ones, with their paws. Depending on the food specialization, the shape and length of the claws, the mobility of the fingers, and the nature of the horny cover on the soles of the fingers vary (for example, the development of sharp horny spines in the osprey). When pecking at prey, some birds support it with their paws (tits, some corvids). Nuthatches are nuts, and woodpeckers put nuts and cones into cracks and, having strengthened them in this way, peck them. Shrikes impale large prey on dry, sharp twigs, and then peck and tear them apart.

Sometimes crows and large gulls, having grabbed hard prey (toothless crabs, etc.), fly up and then throw the prey to the ground; this technique is repeated many times until the shell or shell cracks. Perhaps some birds of prey do this with turtles (vulture) or with large bones (bearded vulture). The use of “tools” by birds is also described. The woodpecker finch, holding a cactus needle or a dry twig in its beak at one end, picks it in the cracks of the bark, driving the insect out and then grabbing it with its beak. When flying from tree to tree, the finch sometimes drags a thorn along with it.

Life expectancy and mortality. Life expectancy is an important biological and demographic indicator, without knowledge of which it is impossible to clearly imagine the patterns of seasonal and long-term movements in population numbers. In birds, lifespan, like most other demographic parameters, is determined almost exclusively on the basis of banding data. The use of ringing for more than 80 years has led to the fact that the lifespan of birds is now known for many species and has been studied in nature better than that of other animals. Birds have an average lifespan, an average expected lifespan, and a maximum lifespan.

Average life expectancy - This is the average number of years of life expected for newborns. Average life expectancy individuals of a certain age is the mathematical expectation of the duration of the upcoming life after reaching this age. Accurate calculation of the average age of death in months of life is possible only if the hatching date of each bird is known, but more often the average life expectancy is calculated in years. Average life expectancy is determined under the assumption that age-specific mortality rates remain unchanged throughout the life of the generation being studied. Under maximum life expectancy refers to the maximum age for the population being studied at which some of its individual members die. This indicator is primarily physiological and relates only to individual results of individual bird tagging, and, therefore, there is no guarantee that this maximum will not be exceeded. It can only indicate the theoretical possibility of living to a certain age. However, the average maximum lifespan in nature and in captivity can differ significantly. In addition, the maximum lifespan of birds depends in a certain way on their body size (Table 5.1).

In passerine birds, the maximum life expectancy exceeds the average expected by 3 - 9 times, and in raptors - 5 times. It turns out that for every thousand birds there are from 1 to 17 individuals at their maximum age.

A comparison of data on the maximum lifespan of birds for one hundred species from different orders allowed us to draw the following conclusions. The maximum lifespan of birds in nature is on average 7 times longer than the expected average (for one-year-old birds) (from 2 to 20). The maximum lifespan in captivity (of course, with appropriate optimal maintenance) is rarely less than in nature, usually longer, on average 1.6 times. Thus, the maximum lifespan of birds in captivity can serve as an indicator of “potential longevity,” which exceeds the average lifespan by an average of 11 times. There is a relationship between the average lifespan of birds and their body weight, expressed by a power function equation.

Table 5.1

Maximum lifespan of birds

(according to V. A. Paevsky, 1985, with modifications)

	Life expectancy, years		Body weight, g
	average expected	Maximum
	average expected	in nature
great cormorant
gray heron
White stork
mute swan
White-fronted goose


Herring gull


Blackbird
song thrush
garden warbler

Mortality, like life expectancy, it is a basic biological and demographic parameter. The relationship between fertility and mortality is the most important aspect of studying population size, since in any population these parameters are in dynamic equilibrium. The mortality rate of adult birds occupies an exceptional position among other demographic parameters. The accuracy of the assessment of other indicators and the general understanding of the patterns of bird population movement depend on the accuracy of determining the average annual mortality of sexually mature members of the population. The mortality rate determines the duration of an individual’s participation in population reproduction and the specific characteristics of the reproduction strategy. Mortality of adult birds, chicks and embryos are distinguished.

Adult birds die from a fairly wide range of causes. Dividing the factors of bird death into natural and anthropogenic is hardly justified in our time. Most species, or at least most observable populations, live in environments that have been transformed in one way or another by human activity. If a population reproduces in some areas closest to undisturbed biocenoses, then during the period of seasonal movements many, if not all, members of such a population encounter certain impacts of civilization. The entire space in which birds are located at different periods of the annual cycle, with individual sections of the cultural landscape, be it a city or agricultural land, can be considered as a single whole, and its individual elements will be more or less natural for different species. Therefore, when considering the causes of bird death, it is impossible to clearly separate natural from artificial causes. For example, the death of birds on the roads is one of the now common factors of mortality, but during periods of sharp cold weather and abundant snow, many birds accumulate on the highway and their death, initially caused by weather conditions, increases from anthropogenic causes. The only mortality factor that is usually considered separately from all others - hunting - can be classified as purely anthropogenic.

When discussing the causes of bird mortality, apparently not all factors of death are taken into account. For example, according to the general opinion of researchers, the main cause of death for nesting chicks is predation, but this factor is rarely indicated in publications on the causes of death of adult birds. It is possible that the carcasses of birds that died from hypothermia, starvation or poisoning are found more often than the remains of birds eaten.

Bird mortality is directly related to reproductive success, which most often refers to the degree of survival of eggs and chicks until the chicks fly from the nest. However, in brood and semi-brood birds, in many cases, only the success of hatching is determined, which is hardly comparable to the success of hatching in chicks and is a specific indicator that is significant only for these groups of birds. The proportion of young birds that have taken wing from the number of eggs laid in ducks, gulls and other non-chicken birds is determined much less frequently than in chick birds; At best, the researcher has an idea of the ratio of young and adult birds at the end of the breeding season, but this may be sufficient to estimate other population parameters.

The success of reproduction varies among birds with brood and nestling types of development, and among the latter, among open-nesting and cavity-nesting birds. In the temperate zone of Europe and America, the breeding success of chicks varies from 22 to 77% (an average of 46%). In open-nesting chicks, of the number of eggs laid, on average, about 65% of the chicks hatch and approximately 47% of the fledglings fly out of the nests. In nestling hollow nesters, the success rate of emergence is 26-94% (on average 66%).

In brood birds, on average, 25% of the birds from the number of eggs laid rise to the wing. The total average loss of eggs in chicken birds per day is 1.6%, which gives an overall hatching success of 45%. Daily egg losses in gallinaceae were found to be quite comparable with those of true ducks (1.6%) and with the losses of eggs and chicks in open-nesting passerines (1.9%), while the daily egg losses of diving ducks (0.8%) were similar with those of sparrow nest nesters (0.9%).

Predation (eating eggs and chicks) is only a special case of any destruction of nests, leading to the death of the clutch and brood. Predation of nests by humans or abandonment of nests due to human disturbance, trampling by livestock of nests on the ground or on reeds - these factors can cause large losses in some places.

In birds of prey and storks, for which the factor of predation itself is somewhat less pronounced, the phenomenon of aggression of older members of the brood towards younger members or cannibalism on the part of parents as an adaptation to possible fluctuations in available food resources can be classified as intrapopulation mechanisms of population regulation.

In the vast majority of populations of various species, the death of eggs and chicks from predators accounts for the largest share - up to 80% of all losses. It is important to note that in small cavity nesters, which have the highest chick survival rate among passerines, fledglings immediately after emergence are also susceptible to potential predation, as are other birds. Under embryonic mortality refers to the total proportion of eggs with dead embryos and unfertilized eggs. Despite the fact that the causes of embryonic mortality itself can be not only anomalies associated with the development of the embryo, but also damage to the shell or its defects, they are usually also counted among the total number of eggs with embryonic mortality. Classifying all of these types of failure to hatch into one loss category is justified because their level may be characteristic of the species.

Despite the fairly high level of species and annual variation in embryonic mortality rates, the overall average values of this indicator as a whole for the order of passerines in different parts of the world are very similar. The proportion of undeveloped eggs from the number of eggs laid in clutches and preserved until hatching was 4.0% for passerine birds of the forest zone of the European part of the former USSR, 5.1% for North American birds, 4.6% for the sub-highlands of the Tien Shan, and 5.8% for the Curonian Spit. For non-passerine birds this figure is often much higher, ranging from 1.7 to 20.3%.

As a result of the influence of all factors that determine the mortality rate from embryonic death to the death of birds on wintering grounds, the real age-sex structure of the population of a particular species is formed. For a finch, for example, it looks like this. From spring arrival until the chicks hatch, half of the entire population consists of one-year-old individuals, i.e. birds participating in breeding for the first time. Birds aged 2 to 3 years - 22%, from 3 to 4 years - 12%. With this structure, for every thousand finches there are only 8 individuals older than 7 years.

In the process of evolution, birds have developed a large number of different forms adapted to life in a wide variety of conditions. Some birds inhabited forests and bushes, where they developed the appropriate paw structure for living among the branches. Other forms adapted to life on the water, and their further development followed the path of specialization in swimming and diving. Some forms, to a greater extent than others, have mastered the air environment and spend most of their lives on the wings, revealing various adaptations in the structure of the wing, ensuring the soaring flight of large predators, the rapid active flight of swifts and swallows. Steppes and deserts are inhabited by a number of species that have adapted to walking and running on solid ground.

Based on the preferred types of landscapes and travel characteristics, the following are distinguished: main ecological groups of birds: arboreal-shrub, terrestrial-arboreal, terrestrial, semi-aquatic, aquatic, flying hunting . It should be noted that, as with any other attempts at biological classifications, a fairly large number of species occupy an intermediate position and their assignment to one group or another turns out to be quite arbitrary, therefore the boundaries between the identified groups are unclear and very arbitrary.

Tree and bush birds. They feed mainly in the crowns of trees and bushes, in thickets of reeds and other emergent plants, where they nest. Nests vary in complexity, in some species they are very skillfully woven, warm and durable; Some species nest in hollows. The bulk of the species in this group are made up of various families of passerines, orioles, some corvids, tits, warblers and many others. This also includes cuckoos and woodpeckers.

While collecting food, birds jump from branch to branch, sometimes helping by flapping their wings. Small birds of this group, clinging to uneven bark with strong fingers with sharp claws, can move along vertical tree trunks (tits, nuthatches, pikas). In real woodpeckers, the structure of the paws changes: two fingers are directed forward, two - back; all fingers bear powerful, strongly curved, sharp claws that reliably cling to any irregularities in the bark. The tail, made of strong, hard tail feathers, is pressed against the trunk and serves as an additional support point. These features allow woodpeckers not only to move along vertical trunks, but also to chisel.

Woodpeckers, having a powerful chisel-shaped beak, chisel bark and wood, opening the passages of insects and their larvae. The long tongue can extend from the mouth almost the length of the beak, has spines pointing backwards at the end and is covered with sticky saliva. The woodpecker inserts its tongue into the open passage and pulls out the prey with its tongue.

Ground-arboreal birds. They are close to the first group in appearance and differ only in that they equally successfully collect food both in the crowns and on the ground. Some species build nests in the crowns of trees and shrubs, nest in hollows, or make a nest on the ground.

This includes some of the grouse (grouse, grouse, hazel grouse), many corvids, thrushes, wrens, starlings, many weavers, finches, and buntings. This group contains both insectivorous species and omnivores, feeding on various invertebrates (and some, such as corvids, and vertebrates), berries, seeds, and vegetative parts of plants. Variations in beak structure correspond to food specialization and are similar to many beak variations in the first group. In the crowns they jump from branch to branch; on the ground, small species usually move in jumps, and larger species (grouse, pigeons, parrots) - in steps. Species of similar sizes can also differ in their gait: for example, blackbirds and magpies jump on the ground, while starlings, jackdaws, rooks, and crows walk. Some species, looking for food, rake the top layer of litter (grouse, blackbirds).

Land birds . A collective group that unites birds with varying degrees of adaptation to a terrestrial lifestyle. Quite a few species retain the appearance of arboreal-shrub or ground-arboreal birds, but feed almost exclusively on the ground where they build a nest, but for rest and in case of danger they willingly perch on trees and bushes. The terrestrial lifestyle of these species is ensured primarily by behavioral characteristics.

Morphological adaptations are not clearly expressed: the claws are usually somewhat less curved, the strong hind limbs of many species allow them to rake the litter in search of food, and some species develop protective coloration. They walk and run on the ground, rather than jumping. They feed on various insects and other invertebrates, collecting them on the ground and grass (by jumping and flying, some also catch flying insects), and eat seeds and berries. These species include some passerines (larks, pipits, wagtails, stonechat), and hoopoe. More distinct adaptations to a terrestrial lifestyle are characteristic of most chickens. The strong hind limbs of these species are relatively short. Strong short fingers end in blunt claws; the rear (first) finger is usually small or completely reduced. All these land birds walk and run well. When in danger, they run away or fly away; many species go into hiding. The food is predominantly plant-based (vegetative parts of plants, seeds, berries, tubers), but they readily, and sometimes in large quantities, eat a variety of invertebrates and small lizards. The beaks of all species are strong, varying in length, usually with a pointed end, ensuring the capture of both animal and plant food.

This also includes a number of long-legged species that in appearance resemble semi-aquatic birds: some crane-like birds (demoiselle crane) and the secretary bird of the diurnal birds of prey. Elongated limbs (especially the tarsus and shin) with strong fingers allow these birds to easily run through tall grass, chasing reptiles (lizards, snakes) and large insects. Prey is grabbed with the beak (cranes) or paws (secretary), then killed with the beak.

Waterbirds. They inhabit a variety of damp habitats: overgrown and open banks of water bodies, extensive swamps. This includes all ankle-bearing, or stork-like, many crane- and chariformes.

Most species of this group are characterized by elongated limbs (the tarsus and tibia are elongated, the lower part of the latter is usually not feathered) with long thin fingers (all four in herons, many rails; in the rest, the hind finger is small or absent), sometimes connected at the base by a rudimentary swimming membrane . This makes it possible to walk and run through thick grass and shallow waters without wetting the feathers and without falling into muddy muddy ground; some species (small rails) easily run on floating aquatic vegetation. As a rule, the lengthening of the limbs is accompanied by a lengthening of the neck: the bird reaches the ground with its beak, only slightly tilting the body. In some species, the body is clearly compressed laterally, allowing it to slide between stems in dense thickets. A carelessly built nest is located on the ground, on creases of reeds, sometimes in trees (herons, storks, ibises).

Water birds. A very diverse group of birds that forage for food by swimming and diving; some feed on land. They inhabit the coasts of the seas and various continental bodies of water. This includes grebes, anseriformes, or lamellar-billed animals, and some rails (coots).

In species of this group, the body is usually flattened in the dorso-ventral direction, which provides greater stability on the water. The plumage is tight-fitting and successfully resists getting wet. Well-developed down and downy parts of the webs of contour feathers improve thermal insulation; This is also facilitated by the strong development of subcutaneous fat deposits. All this allows

Swim and dive in cold water for a long time. The hind limbs are relatively short; three fingers pointing forward are connected by a well-developed swimming membrane. Only grebes, rails (coots) and wading sandpipers do not have a swimming membrane, but each of the three forward-pointing toes is equipped with elastic and strong horny edges, which also noticeably increase the paddle surface of the paw. In good diving species, the sternum usually lengthens and the number of ribs increases (improving the protection of internal organs from external pressure), the pelvis narrows, and in some good divers the legs move back (grebes).

Aquatic birds usually nest near water bodies, more often on the ground, less often on reed creases and trees. Grebes and coots build floating nests in thickets of emergent vegetation.

The vast majority of species in this group are carnivorous: they feed on fish and various aquatic invertebrates. When swimming, phalaropes use their thin, pincer-shaped beaks to peck various small invertebrates from the surface of the water and leaves of emergent plants. Coots of moderate length, which feed mainly on plant foods, have a strong beak that makes it possible to tear off pieces of plants and grab aquatic animals. In Anseriformes, at the end of the widened beak there is a well-developed thickened area - the nail, which forms a small hook; horny plates along the edges of the beak and mandible and on the sides of the fleshy tongue form a filtering apparatus that releases water and silt, but retains food objects in the oral cavity: various small animals and seeds. A strong nail allows you to tear off attached mollusks, parts of plants, etc. In ducks that feed on small animals, especially shovelers, the plates of the filtering apparatus are thin, long, and very dense. In eiders, which feed mainly on relatively large attached mollusks, and geese, which feed largely on land on land plants, a strong nail at the end of the beak and rough, more sparsely seated plates along its edges make it easy to tear off and crush mollusk shells and pluck fresh greens. In mergansers, these plates turn into teeth, making it easier to hold the fish.

Birds hunting on the fly. A heterogeneous and diverse group, including representatives of many families whose close relatives are included in the previously described groups. More common in open landscapes.

Quite a few species in this group are associated with water. These are birds with long, narrow, pointed wings, capable of maneuverable flight and usually capable of long soaring. The fingers are connected by a swimming membrane. Relax on the water or on the shore. The most common way of hunting is to fly at different heights above the water and quickly dive on prey (fish, large invertebrates) seen on the surface or in the upper layer of water. Due to the energy of the dive, birds can plunge into the water, at this moment grabbing prey with their beaks. This is how gulls, terns and phalaropes hunt. Seagulls often collect food by wandering in shallow waters and on land.

Hawks use two methods of hunting: the predator sits in cover and suddenly rushes at the approaching prey, or it flies more often along the edges and grabs the frightened prey in a quick throw. They are characterized by relatively short wings and a long tail, allowing them to pursue prey among branches. Having fast, maneuverable flight, falcons usually fly around their hunting area and, in a swift dive - dive - grab the prey they encounter in the air or on the ground. When looking out for prey on the ground, small falcons are capable of hovering in the air for a short time in a fluttering flight. In addition to the main method of hunting - looking out for prey in flight and grabbing it in flight - many predators catch large insects, wandering on the ground, lying in wait near rodent burrows, and dragging chicks from their nests.

Owls search for their prey in flight or lie in wait while sitting in ambush, and catch it in a short throw, grabbing the victim with their paws. Unlike diurnal birds of prey, the main receptor for detecting and grasping prey in owls is not vision, but hearing. Nightjars, like owls, lead a crepuscular and nocturnal lifestyle; They feed mainly on large insects, which they catch in the air or, less commonly, peck in flight from branches on the ground. They also have silent, maneuverable flight and soft plumage, although not to the same extent as owls. Long, sharp wings, rapid, maneuverable flight, a small beak, but a very wide mouth, bordered at the corners with hard bristles, are characteristics of swifts and swallows, which are ecologically close to them. Swallows catch prey only in flight; they do not use other methods of hunting. They feed on small insects. Swallows are able to peck sitting insects from branches and leaves in flight. Only in flight do bee-eaters catch large flying insects. Quite long beak, tapering towards the end, slightly curved downwards, lack of long bristles in the corners
mouth - these features of bee-eaters are associated with the larger size of their prey compared to the food items of swallows and swifts.

This classification is schematic, but it gives a fairly complete picture of the ecological diversity of the class of birds. They have mastered almost all niches suitable for life: only sea depths over 50–60 m and the thickness of the soil remain inaccessible to them (although some species dig nesting holes).

Trophic groups of birds

The food spectrum of the bird class is quite wide and includes a variety of plant and animal foods. The variety of bird feeds used is usually divided into three groups: polyphagous, stenophagous and intermediate.

Polyphages (omnivores) They feed on a wide variety of plant and animal foods. Approximately 1/3 of families can be attributed to this group, and within each family, omnivory is more pronounced in larger species. Examples of the most typical polyphagous birds are large corvids (ravens, crows, etc.), large gulls, and cranes.

Stenophages - species that consume uniform food and use uniform methods of catching prey. Stenophagy is relatively rare among birds. Stenophages include swifts and many nightjars, which feed only on flying insects, and swallows, which also catch insects in the air, but can also peck them from plants in flight. This group also includes typical scavengers, as well as species that feed only on large fish, such as osprey. Stenophages also include crossbills, which feed mainly on the seeds of coniferous trees.

Intermediate group makes up the majority of birds that use a fairly wide range of feeds for feeding. These are many passerines that feed on both various insects and seeds. Grebes feed on fish and a variety of large aquatic invertebrates; green parts of plants, berries, seeds and various invertebrates - galliformes.

Based on the composition of food, a number of ecological groups are also distinguished in the class of birds. Species that feed primarily on plant foods are called Phytophages . Geese, swans, some ducks, and coots feed mainly on a variety of coastal and aquatic vegetation, simultaneously eating various aquatic animals. Green parts of plants, berries, seeds, buds, catkins - the basis of food for galliform birds. Many passerines feed primarily on seeds - weaver birds, finches (especially crossbills, grosbeaks, greenfinches), and larks. However, all phytophages, if possible, use a variety of animal foods to one degree or another; their consumption especially increases during the breeding season, since most of these birds feed their chicks mainly with animal feed.

Species that feed primarily on animal foods are called Zoophages . Although many of them eat plant foods, albeit to a small extent. Nearly a third of living bird families are exclusively or predominantly insectivorous (entomophagous ); Almost all birds use insects to one degree or another. Many aquatic and semi-aquatic species feed primarily on fish (ichthyophages), simultaneously eating aquatic invertebrates.

Many birds of prey and owls are Myophages, that is, they feed mainly on small rodents. Few birds of prey can be called ornithophages : hawks, falcons (peregrine falcon), marsh harrier and some others feed mainly on birds.

TO herpetophagous (feed on amphibians and reptiles) include the snake eagle, secretary bird, and some large kingfishers. However, such a division by type of nutrition is largely arbitrary and schematic.

Changes in nutrition are typical for all groups. Typical ornithophages, for example, on occasion catch mammals, lizards and large insects.

Immature hatchlings eat what their parents bring to them. In many species, age-related variability in nutrition is well expressed, due to the selective supply of food by adult birds, which undoubtedly significantly accelerates the growth and increases the survival rate of chicks. Thus, great tits try to carry spiders to newly hatched chicks, sometimes squeezing only their “contents” into the chick’s open beak, and swallowing the “shell” themselves. After two to three days, parents begin to feed small larvae, caterpillars, butterflies with torn wings, aphids and other soft insects to the chicks, and they often feed the already grown, fledged chicks with beetles. The adult birds themselves eat at this time any insects available to them. Other passerines act in a similar manner.

Methods of obtaining food

Birds' methods of obtaining food are not very diverse. The vast majority of species take prey with their beaks. In accordance with food specialization, the shape and relative sizes of the beak vary widely. Straight or curved, very long and thin beaks of waders and some passerines allow them to extract food from moist soil or narrow and deep shelters. The sharply conical beaks of many granivorous birds, powerful at the base, make it easier to grasp and chew seeds. The powerful beaks of birds of prey, owls, and partly shrikes, with a sharp “hook” varying in length on the beak, help to hold and tear food; beaks with numerous plates along the edges, which allow filtering small prey, are characteristic of Anseriformes. Small beaks with a very large mouth opening and bristles at its corners in swifts, nightjars and swallows form a kind of “net” that makes it easier to catch small flying insects.

The shape of the tongue is no less diverse, which in many birds not only helps in swallowing a bolus of food, but is also involved in grasping and holding prey. Thus, the strongly protruding tongue of woodpeckers, usually equipped with sharp spikes at the end, allows one to feel the larva in the hollow passage and pull it out. The fleshy, mobile tongue of many seed-eating passerines, along with the ridges on the palate, makes it possible to conveniently place a seed or nut on the edge of the beak to crack the shell. Birds that catch fish and a variety of aquatic invertebrates have numerous sharp spines on their tongues, directed towards the pharynx, making it easier to hold and swallow prey (grebes, mergansers). The fleshy and mobile tongue of anseriformes, bordered with plates, is involved in filtering food.

Daytime predators and owls grab prey, especially large ones, with their paws. Depending on the food specialization, I vary the shape and length of the claws, the mobility of the fingers, and the nature of the horny cover on the soles of the fingers (for example, the development of sharp horny spines in the osprey). When pecking at prey, some birds support it with their paws (tits, some corvids). Nuthatches provide nuts, and woodpeckers insert nuts and cones into cracks and, having strengthened them, peck them. Shrikes impale large prey on dry, sharp twigs, and then peck and tear them apart.

Sometimes crows and large gulls, having grabbed hard prey (toothless crabs, etc.), fly up and then throw the prey to the ground; this technique is repeated many times until the shell or shell cracks. Perhaps some birds of prey do this with turtles (vulture) or with large bones (bearded vulture). The use of a “tool” by birds, the woodpecker finch, is also described, holding a cactus needle or a dry twig in its beak at one end, picking it in the cracks of the bark, driving the insect out and then grabbing it with its beak. When flying from tree to tree, the finch sometimes drags a thorn along with it.

Ecological groups of birds

An ecological group unites different types of organisms that have similar adaptations to certain environmental conditions or lifestyles. Ecological groups of birds are distinguished on the following basis: by the nature of their diet, by their habitats, by the nature of their nesting and some other characteristics.

Birds from different, sometimes distant from each other, systematic groups often fall into the same ecological group, since taxonomy is built on the basis of genetic proximity, degree of relationship, and common origin.

Ecological groups of birds by habitat

By habitat There are four groups of birds:

Forest birds They differ from other groups in that they have rather small legs, as well as medium-sized heads. Their neck is not visible, their eyes are on the sides.
has a very long neck and long legs. They need them to get food in the swamps.
Birds of open spaces They are adapted to migration and therefore have very strong wings. Their bones weigh less than those of other types of birds.
The last group are waterfowl who live near or in bodies of water. These birds are distinguished by a fairly powerful beak, which helps them feed on fish.

Birds of the forest. Most modern birds are associated with forests. Everyone knows our forest birds: tits, woodpeckers, thrushes, hazel grouse, black grouse, wood grouse, well adapted to life in forests. They have short, rounded wings and long tails. This allows the birds to quickly take off and maneuver between trees.

Among forest birds there are herbivores (granivores), insectivores, predators and omnivores. Depending on the nature of food, birds have differently developed beaks and limbs.

Large forest birds - hazel grouse, black grouse, wood grouse - spend a lot of time on the ground. With strong legs armed with large claws, they rake the forest floor, selecting seeds of plants, insects, and earthworms. With strong beaks they bite buds, young shoots of trees and shrubs, and feed on juicy blueberries, blueberries, and lingonberries.

They have a typical appearance for forest birds magpie And goshawk : relatively short, rounded wings and a long tail. These birds maneuver beautifully among forest trees and have nimble flight. However, due to the use of different foods, their legs and beaks are developed differently. Hawk - predator: its prey is various small birds. With strong legs armed with powerful claws, the hawk grabs its prey and dismembers it with its curved predatory beak. The magpie has a small cone-shaped beak, which helps it eat a variety of foods (be omnivore ): collect fruits and seeds from the ground, grab insects, worms, a large beetle, and even catch a small mouse.

Birds of open spaces They live in meadows, steppes, and deserts. They spend a lot of time on the ground, looking for food among plants. They have strong legs and a long neck, allowing them to detect enemies at great distances. One of the typical representatives of the steppe regions of our country - bustard. This is a large bird weighing 15-16 kg, feeds mainly on plant foods. Possessing a protective coloring, it often hides among vegetation, becoming completely invisible. The nest is made on the ground, in areas of virgin steppe. Brood type chicks. Due to the plowing of virgin steppes, the number of bustards has sharply decreased, and it is included in the Red Book of Russia.

Typical birds of open spaces are ostriches.

Waterfowl They swim well, many dive. They have a flattened, boat-shaped body, webbed feet, and legs set far back. They move along the ground, clumsily waddling, with a duck's gait. The plumage is thick and has water-repellent properties: the feathers are prevented from getting wet by the secretions of the coccygeal gland, with which the birds thoroughly lubricate the plumage. Representatives of waterfowl - ducks,geese, swans .

A typical representative of waterfowl - mallard duck feeding in shallow water. Along the edges of its flattened wide beak are horny denticles . When the jaws are not fully closed through the lattice formed by the teeth, the ducks filter the water, leaving food objects in the mouth: crustaceans, insect larvae, small fish, vegetative parts of plants. The mallard feeds at shallow depths. Sometimes, lowering its head into the water, turning over and exposing the back of its body from the water, it collects food from the bottom and strains it. Mallards make nests on the ground among plants. The nest is lined with its own downy feathers plucked from the chest and belly. There are 8-14 eggs in a clutch. Brood type chicks.

Birds of the coasts of reservoirs and swamps They live on the banks of reservoirs and in swamps and have many common structural features. They have long thin legs and neck, and a large beak. In swampy places, their body, raised high above the ground, does not get wet. They feed on frogs, fish, insects, worms, and mollusks. Moving through swamps and coastal shallows, they use their beaks, like tweezers, to grab prey. These are storks, herons, waders . Many of them nest on the banks, not far from the water, others make nests in trees. Storks have long lived next to humans. People take care of them by creating platforms for nests.

Seabirds - guillemots, puffins, gulls - form bird markets on steep cliffs. They are adapted to hover over the sea surface.

Ecological groups of birds by nesting sites

There are five groups of birds in total. nesting sites . The main difference is only in the type of nest in which these birds live:

Crown-nesting birds they build their nests, as the name suggests, in the crown of trees ( orioles, zabliki).
Bush birds place their nests near or in the bushes themselves ( wren, robin ).
Ground-nesting decide to place their nest directly on the ground ( larks, pipits, buntings, waders ).
Hollow-nesting birds live directly in hollows ( woodpeckers, tits, pikas, flycatchers ).
And the last group of birds, burrowers (sand martins, bee-eaters, kingfishers) , live in burrows, underground.

Ecological groups of birdsby food type

On this basis, four groups are distinguished. Representatives of each of them eat a certain type of food:

Insectivorous birds (For example tits or pikas) have thin pointed beaks, thanks to which they can pull their prey off leaves or out of thin crevices.
Herbivorous birds , including granivores (For example greenfinches) have a powerful beak thanks to which they can break through the dense shells of fruits. And the sharp ends of the beak help us pull out seeds from the cones of various trees.
Predator birds (For example eagle) feed on a variety of small birds. They have strong legs with powerful claws, thanks to which they grab prey.
Omnivorous birds (For example magpie) have a cone-shaped beak that helps them feed on different types of food.

Insectivorestits, pikas, kinglets, warblers They have thin pointed beaks that allow them to get insects from crevices in the bark, grab them from leaves, and remove them from the scales of cones. Sharp claws and long fingers allow these birds to stay on branches.

A peculiar group of birds that forage in the air - swallows And swifts. They spend almost their entire lives in the air, hunting for insects from morning to evening. They have long sickle-shaped wings. The beak is small, and the mouth opening is huge, the corners of the mouth go behind the eyes. With their mouths wide open, they catch flying insects, while the size of the oral funnel is increased by the bristles located at the corners of the mouth. In good dry weather, insects rise high above the ground, and when air humidity rises, the wings of insects get wet and they fly low above the ground. Swallows and swifts follow them, so the flight of swallows and swifts predicts the approach of rain.

Granivorous birds - greenfinches, bee-eaters, grosbeaks . They have a powerful beak, which is used to split the dense shells of fruits. So grosbeak successfully breaks the strong fruits of bird cherry and cherry. Sharp ends of crossed beak crossbills allow them to deftly extract seeds from pine and spruce cones.

They have common characteristics predators. They have large, strong legs armed with sharp claws and a hook-shaped beak. They have such signs diurnal carnivores birds, owls and even shrikes, related to songbirds. The prey of many predators are small animals, which they look out for from great heights, flying over the fields. Other predators catch small birds, feed on fish and large insects. Birds of prey fly beautifully, among them there are those that soar for a long time, for example buzzards,eagles And vultures. Falcons chase prey in the air, and then, diving on it, can reach speeds of up to 300 km/h. They have sharp, crescent-shaped wings that enable fast flight.

Representatives of the bushbird family have 2 pairs of muscles of the lower larynx. The family has 1 genus Atrichornis, which includes 2 species. These birds are almost the size of a starling, with a long tail and short and weak rounded wings. The general color is brownish, the throat is white, there is a black band on the chest, and the sides are reddish. Males are brighter colored and slightly larger than females. The legs of bush birds are strong; they use them to dig through the litter in search of food - mollusks, worms, and various insects. The voice is strong, the song includes many imitations of the voices of other birds and other sounds. The nest is built from grass and dry leaves, with a roof and a side entrance, and placed on the ground.

Rufous bushbird(A. rufescens), 17 -18 cm long, lives in the wet rain forests of the eastern slope of the Great Dividing Range, on the border of Queensland and New South Wales. The habitat of this bird is Lamington National Park. Nesting - in spring (September - November), in a clutch of 2 pinkish eggs with specks.

Noisy bushbird(A. clamosus) - larger, about 22 cm long, inhabits a small area in the extreme southwest of Australia - the coast of Two People Bay near the city of Albany. Lives in coastal bushes, almost does not fly, runs quickly under the canopy of bushes. The singing is very varied, similar to that of a nightingale; the birds often sing in duets. Nests in winter (June), clutch contains 1 whitish speckled egg. This species was considered extinct for a long time, since since 1899, for more than 80 years, it could not be found in nature. The population of Two People Bay was discovered in 1961, and now a reserve has been organized there.

Shrub birds are listed in the Red Book of the International Union for Conservation of Nature.