The spider kills the male after mating. Ten species of animals with strange sexual behavior
Little swan ( Cygnus bewickii) is listed in the Red Book of Russia
Habitat
Small swan, or Tundra swan ( Cygnus bewickii) is typical for the tundra of Eurasia and nests in it from the north of Fennoscandia to the Kolyma delta, as well as on the western islands of the Arctic Ocean. In early May, at the end of the polar winter, he is one of the first to return to his northern homeland. The nesting biotope of the little swan is swampy and grassy lowlands of the tundra, moving with numerous open lakes of various sizes; river valleys, replete with oxbow lakes and channels. Swans arrive at the nesting sites in pairs. Experienced couples here occupy last year's nests - solid structures up to a meter in diameter and half a meter in height. Made of grass and moss, these “bumps” are quickly released from the snow, so swans can begin laying eggs earlier than other feathered inhabitants of the tundra.
Social behavior and reproduction
The character of the little swan is nasty, uncooperative and aggressive: in its territory it does not tolerate the presence of its own kind, or even geese and ducks. A clutch of 2-4, rarely 5-6 eggs is incubated mainly by the female, with the male guarding her nearby. When they see a person, the birds “crawl away” from the nest, bending their necks, and take off only when as a last resort. After the chicks hatch, the swans move to the water and, together with their brood, stay in the lakes of the tundra and feed along their coasts, sometimes going ashore. IN sparsely populated areas Having noticed an approaching four-legged predator, the male rises on his wings and flies towards him, driving away the predator with his very appearance. He performs the same maneuver when a person approaches. In such cases, the female takes the chicks away from the shore and lies with them among the plants and stones of the coast. Young swans take wing at the age of about 50 days.
Nutrition
The small swan feeds mainly on plant foods: aquatic and terrestrial plants, in particular grass, berries, potato tubers and beets, and also aquatic invertebrates, and sometimes small fish.
Subspecies
- Western tundra swan ( Cygnus bewickii bewickii)
Hello everyone, help me with this task:
What species criteria are used to describe animal species?
1) The mute swan often bends its neck in the shape of the letter S, and holds its beak and head inclined towards the water. When irritated, it makes a characteristic hissing sound, which is how it got its name. The mute swan is distributed in isolated areas in central and southern Europe and Asia from southern Sweden, Denmark and Poland in the west to Mongolia, Primorsky Krai and China in the east. It is rare throughout this territory, and in many areas it is completely absent. Pairs often nest at great distances from each other. Inhabits estuaries, lakes, and sometimes even swamps overgrown with aquatic vegetation, preferring remote areas that are rarely visited by humans.
The small, or tundra, swan is distributed throughout the tundra of Asia from Kola Peninsula in the west to the Kolyma delta in the east, covering the forest-tundra region and the western islands of the Arctic Ocean. For nesting, it chooses marshy and low grassy areas with lakes scattered throughout them, as well as river valleys replete with oxbow lakes and channels.
Mating games are unique and take place on land. At the same time, the male walks in front of the female, stretches his neck, sometimes raises his wings, making a special flapping sound with them, and screams loudly.
2) City swallow. The top of the head, back, wings and tail are blue-black, the rump and the entire underbody are white. The tail has a sharp triangular notch at the end. Inhabitant of mountain and cultural landscapes. Nests on the walls of rocks and buildings. Migrant. It stays in flocks in the air or sitting on wires; it lands on the ground more often than other swallows. Breeds in colonies. The nest is made from lumps of clay in the shape of a hemisphere with a side entrance. Clutch of 4-6 white eggs in May - June. The voice is a ringing “tirrch-tirrch.”
Shore swallow. The top of the head, neck, back, wings, tail and stripe across the chest are grayish-brown, the throat, chest and belly are white. Tail with a shallow notch. Inhabits river valleys, where it nests along steep banks.
Small swan forms separate species in the duck family of the order Anseriformes. This bird gravitates to Arctic and subarctic latitudes. Breeds in the coastal lowlands (tundra) of Eurasia from the Kola Peninsula to the Pacific coast. Today there are 2 populations. One is western, and the second is eastern. The border between them is considered to be the Taimyr Peninsula. The birds arrive at their nesting sites in mid-May. And they leave the cold north in the last days of October.
The western population is waiting frosty winter in Western Europe. These are Denmark, the Netherlands and England with the islands. Mostly on the south coast North Sea. The eastern population migrates much further. It reaches the southern coastal regions of China and even the island of Taiwan. Some birds fly to Korea and Japan. Some birds from both populations fly to Iran and the southern Caspian Sea. The Aral Sea was once considered their favorite place. But currently it is subject to environmental disaster, therefore not only swans, but also other birds avoid it.
The bird is small compared to other representatives of the swan genus. The body length reaches 1.15-1.4 meters. The wingspan is 1.7-2 meters. The weight of the bird ranges from 3.5 to 7.5 kg. Average weight for males it is 6.4 kg, and for females this figure is 5.7 kg. At the same time, the eastern population is slightly larger than the western one. The bird's beak has 2 colors - black and yellow. The color is yellow from the base, and the second half of the beak is black. Moreover, there is more black than yellow. The eastern population has less yellow on its bill than the western population. The plumage has White color, legs are dark. There is no sexual dimorphism between the sexes.
Reproduction
This bird is monogamous; pairs form for the rest of its life. They nest in sparse colonies. The tundra is large, and the distance between nests can be 2-3 km. A nest is built in a wetland. For this, a relatively dry hill is selected. The nest is a mound of branches. At its top there is a depression, which is lined with feathers. The female plucks them from her chest. There are usually 3-5 eggs in a clutch. The incubation period lasts 30 days. The hatched chicks are covered with light gray down. They fledge after 40 days, and 2 months after birth they begin to fly. Young people live with their parents until next spring. The little swan becomes sexually mature in the 3rd year of life.
Nutrition and numbers
The main diet consists of plant food. These are aquatic and land plants. These include algae, grass, berries. Potato tubers and beets are eaten. A small percentage comes from animal food. These are fish and shellfish. As for the numbers, then total birds are approximately 50 thousand individuals. The eastern population is slightly larger than the western one. The fewest birds are found in Iran in winter period. No more than 1000 individuals fly there. In Europe, about 18,000 birds wait out the winter, and in East Asia 20,000 birds. Other representatives of the species visit cold period years other regions.
Cygnus bewickii, Yarrell, 1830
Order Anseriformes
Family Ducks - Anatidae
Short description. Very similar to the whooper swan, but smaller in size. The beak of the small swan is half black, and yellow on the beak it extends onto its black top at a right or almost right angle.
Habitats and biology. Breeds in forest-tundra and tundra of all types of Eurasia. Migrations coincide in timing with the migration of the tundra bean goose or are slightly ahead this type. Spring sightings are few, but judging by observations in the Selenga delta, it flies in May. Autumn migrations are observed in late September - early October. Individual pairs and individuals may linger in the region until the end of October. During the migration period it stops mainly at large bodies of water. The clutch size is from 1 to 6 eggs, usually 3-4 eggs of white or yellowish color. There is no downy lining in the nest. The male takes part in incubating the clutch. The duration of incubation is 30-35 days, the chicks fled at the age of 45-50 days. The food is mainly plant-based, for the most part ground herbaceous plants.
Spreading. In the Cis-Baikal region it is found only during periods of migration. IN late XIX centuries, an insignificant flight was known in Southern Baikal (village Kultuk) and on the Angara in the vicinity of Irkutsk. At the beginning of the 20th century, a male swan was caught on the Angara Islands in September 1902. Already during this period, this species was considered quite rare here. In the first half of the last century, the passage of the small swan was recorded according to west coast Baikal in the valleys of the Irkut, Angara and Lena rivers (in upper reaches) . In these places it is still found on migration. In addition, migrations of this species were known along the river valley. Lower Tunguska. At the end of I960 - early 70's. it began to be encountered during migrations at the Bratsk Reservoir. Within the upper part of the Oka spur, individual pairs in the spring and small flocks of up to 15 individuals in the fall were observed almost every year (1968-72). Late autumn, October 17, 1971, during a period of extremely unfavorable weather conditions (squally wind with heavy snowfall), a well-defined flight of the small swan was observed here in the area from the mouth of the river. Kamenka to the mouth of the river. Katagyrova. It is also found within the forest-steppe part of the Angara spur of the same reservoir. At the beginning of May 2006, four birds were noted on a pond near the village. Ust-Ordynsky. At the end of September 2006, a pair of small swans stayed on a pond near the village. Turgenevka Bayandaevsky district. A massive migration of this species was also observed on October 2-5, 1983 at the watershed of the river. Irkut and r. Toysuk in the Zurku-Zun Loop region. In the second half of the 20th century, migrations of the little swan near Irkutsk were not recorded. However, in beginning of XXI century, a pair of birds was encountered in October 2006 on the Angara in the area of the Yunost and Shishilovsky islands.
Number. On migration it is not large, but clearly higher than previously thought - on October 17, 1971 in the area from the mouth of the river. Kamenka to the mouth of the river. Katagyrov counted about 150 individuals. A massive migration of this species was also observed on October 2-5, 1983 along the Zurkuzun loop (Irkut River). The total number of birds, estimated by the number of flocks flying and the average number of birds in a flock, was about 500 individuals. In other areas of its flight, individual individuals, pairs and flocks of up to 50 birds were observed. Taking into account the fairly wide flight front, from the river valley. Lower Tunguska to the Lena Valley and to the east - to the river. Olekma, total number birds migrating to the Baikal region should be at least 1000 individuals.
Limiting factors. Associated with the nesting area and wintering grounds. In the Cis-Baikal region, cases of shooting of this species are rare. Despite a special wide survey of the population in the places where it migrated, we were not able to collect morphological material on this species.
Accepted and necessary measures security. The small swan is protected in nature reserves, nature reserves and Pribaikalsky national park. Due to the very low number and short period of stay in the territory Irkutsk region The greatest importance is to educate the population with the publication of special booklets on rare and specially protected species.
Information sources: 1 - Gagina, 1958; 2 - Gagina, 1960; 3 - Gagina, 1961; 4 - Durnev et al., 1996; 5 - Dorogostaisky, 1913b; 6-Dybovsky, Godlevsky, 1870; 7-Maleev, Popov, 2007; 8 - Melnikov, 1999a; 9 - Melnikov, 2003; 10 - Polyakov, 1873; 11 - Tachanovsky, 1877; 12 - Ryabitsev, 2008; 13 - data of the compiler.
Compiled by: Yu.I. Melnikov.
Artist: D.V. Gumpylova.
In the past, swans were plentiful and hunted for their meat, down and feathers, but now these birds have become rare and are protected.
The smallest and most numerous - lives mainly in the tundra zone. It is two times lighter than swans of other species (weighing 5-6 kg). This swan has not yet lost its commercial importance, however, its number is gradually decreasing and barely reaches 10 thousand individuals.
The tundra swan has white plumage, a black beak with yellow spot at the base, paws are black, voice is ringing, melodic (with a metallic tint). Swims in water maintaining an upright posture, holding its head at a right angle to its neck.
Tundra swans winter off the coast Western Europe(mainly from British Isles) and Southeast Asia, rarely in the Caspian Sea, Transcaucasia and Central Asia. Their main food is the lush grasses of coastal meadows, in shallow waters - algae and partly fish. In the beginning of May tundra swans They fly home, having previously split into pairs. There is great mutual affection between the female and the male.
For the nest, a dry area is chosen near the lake, in a moss swamp or in the lowlands of the open tundra, among river oxbows and channels, the banks of which are covered with well-developed vegetation. The nest takes up a lot of space (up to 1 m in diameter) and consists of moss and grass, and the tray is lined with down with a small admixture of feathers. There are usually 2 (less often 3) white eggs in a clutch.
The male protects his nesting area from the invasion of foreign swans and protects the brooding female.
About a month after the start of incubation (in July), chicks hatch, covered with gray down. Now the family moves to the water, where the kids feed in shallow water on various crustaceans, mollusks, and larvae of aquatic insects. Swans cannot dive, so they have to get food from the bottom, capsizing upside down, and with their beaks grab underwater parts of plants and small animals inhabiting the muddy bottom. Since the chicks cannot yet obtain food on their own (although they make attempts to capsize like adults), parents help the swans catch small animals by stirring up the water with oscillatory movements of the body and paws. In this case, the food rises from the bottom and enters the chicks’ mouths.
Tundra swans develop quickly and fly on the wing after 40 days. In conditions short summer such precocity is an adaptation to life in the Arctic. Grown-up broods switch to succulent food, eating cereal plants coastal meadows, sedge and cotton grass. In September, flocks of moulted swans flock to their usual wintering grounds, where they remain until spring.
Swans are commercially hunted for their tasty (but tough) meat and snow-white down and feathers.