Nuncrane
| Nuncrane | ||||||||||||
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Barnacle crane ( Grus leucogeranus ) |
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| Scientific name | ||||||||||||
| Grus leucogeranus | ||||||||||||
| Pallas , 1773 |
The Siberian Crane ( Grus leucogeranus , Syn. : Leucogeranus leucogeranus ), and Siberian Crane , is a rare species of bird in the family of cranes . Because of its predominantly white plumage, which it only has in common with three other recent crane species, it is also called the snow crane . During the breeding season it lives in pairs and on the move in family groups of three or small flocks of five to seven birds.
The barnacle crane is considered to be the most aquatic form of the cranes and is dependent on wetlands throughout its life cycle. Barnacle cranes suffer from the destruction of their habitat in both their breeding and wintering areas. They have the longest migration path of all cranes and one of the longest known migration routes of birds that do not cross the oceans. Since the barnacle crane is hunted on its three remaining migration routes, it is considered to be very endangered.
features
Adult bird
The 140 cm long barnacle crane weighs 6 kg, with the male being slightly larger than the female. Otherwise there is no gender dimorphism .
The barnacle crane is a bird with predominantly white plumage. The bare skin on the forehead, crown and sides of the head is bright red and covered with sparse dark and white hair-like bristles. The wings of the hand are shiny black, which is only visible when the crane spreads its wings. In wild birds, the back of the neck and shoulder area is often discolored by iron oxide and then looks reddish or gray.
The iris is yellow to whitish. The legs are rose red with black shields on the front of the barrel. This shade of red is brighter during the breeding season. The beak is bent slightly downwards. The beak is longer and heavier than most other cranes, which is probably an adaptation to foraging in deeper water. It is also slightly curved and serrated at the tip so that the crane can better grasp its food.
Young bird
Freshly hatched dune young have short, dense dunes on the upper side of the body that are intensely reddish maroon brown. The underside of the body is lighter with a more yellowish tint. The second downy dress that downy boys wear from the second to third week of life is less intense and has reddish gray tones, especially on the neck and stomach. The iris is dark brown, the beak is initially pink-flesh-colored and then darkens. The initially light green legs also darken. They wear their first youth dress from the age of seven to eight weeks.
The plumage of the young bird is rust-brown on the head and neck, otherwise light brown and gray. The color distribution is highly variable, the iris is cloudy blue and the legs red-brown. In the first spring dress, the head, neck and top of the body are already white with a more or less large proportion of rust-red feathers. The underside of the body is already pure white. In the second autumn-winter dress, the plumage only shows individual rust-red feathers. The wings of the hand and arm are only as feathered as they are in the third year of life, as is characteristic of adult birds.
voice
In contrast to most migrating cranes, the windpipe is simple and only slightly curved. It shares this trait with the African rock crane, among others . Nun cranes are very happy to call and have the longest double call among cranes. This common calling of the two partner birds, also known as a unisone duet, is usually introduced by the male. The male bows and gives a nasal yeah! out. Then it unfolds its wings and, together with the female, calls Tuudel-luu, tuudel-luu, tuudel-luu in a duet . During the duet, it stands either parallel to the male or opposite him. The female, who has a slightly higher voice, calls tuudel and the calls are synchronized between couples so that they sound like the call of a single bird. During the time of the train they shout a bright, bell- clear tuut-tuut-tuut . The unisone duet plays a major role in the behavioral repertoire of the nun cranes and serves, among other things, to mark the territory. Barnacle cranes perform this duet in different situations and at different times of the year.
Locomotion and behavior
As with other crane species, the flight of the barn crane is calm and straight with powerfully spreading wings. Before landing, the barnacle crane goes into a glide flight. To be blown up, it must first make a small run-up.
The barnacle crane is considered to be one of the most territorial and aggressive crane species. Demonstrations of aggression therefore play an important role in his behavioral repertoire. The unisone duet described in the voice section supports territoriality in the breeding areas. In the wintering areas, the territoriality falls sharply. Threatening gestures can also be observed here. They serve to maintain the hierarchy in the group. The gestures of aggression also include a demonstrative approach to a rival. The neck is stretched and the beak is pressed against the neck. When walking, the bird lifts its leg well out of the water before taking the next step. When the degree of aggressiveness is very high, the nun cranes show the same introductory signs as in the unison duet. Instead of shouting, they put the tips of their bills on their backs, spread their wings and let out a rolling growl that can only be heard a few meters away.
Distribution, migration and habitat
Cranes are generally regarded as relic birds that are very difficult to withstand increasing anthropogenic pressure, regardless of whether this is caused directly by hunting or indirectly by habitat destruction. This is especially true for the barnacle crane.
In the Pleistocene , nun cranes were still spread over the Asian lowlands with their large marshes and swamps. In the 19th century they were only found scattered in their northern breeding areas. The species is very difficult to protect because it breeds widely and has a long migration route that passes through several countries.
An eastern population breeds in northeastern Siberia and winters on the central Yangtze . The main wintering area here is the Poyang Hu . This is the main population with up to 3,000 cranes. A western one breeds south of the Obs and east of the Urals and spends the winter in Iran on the south bank of the Caspian Sea . However, there are only about ten birds. The biotopes used by the two remaining populations are very different. The western one lives in very wet lowland-moss-sedge-cottongrass-tundras with a multitude of large and small lakes. The eastern population, on the other hand, inhabits vast swamp massifs rich in lakes in the middle of the northern larch taige and prefer sphagnum sections here, which are near small and often dry larch forests.
Medium-sized populations that were breeding in Western Siberia are now probably extinct. These so-called Central Siberian populations overwintered in the Indian Ganges Basin, where numerous ponds and monsoon ponds offered them suitable wintering quarters around the turn of the 19th and 20th centuries. With increasing population density and an expansion of agricultural areas, the wintering nun cranes concentrated more and more in a swamp area of around 30 square kilometers, which is 60 kilometers west of Agra . This area is now a national park. The Keoladeo National Park offered the birds sufficient protection during their wintering season, which was also shown by the fact that only a few birds died in the wintering quarters. The migration route of this population presumably led over the Thar desert , the Punjab and the Indus valley in Pakistan . From there they flew in a north-westerly direction to Lake Ab-e-estada in the valley of Kabul in eastern Afghanistan , then in a north-westerly direction over the Hindu Kush, before crossing Central Asia in a north-east direction. It took the birds about two months for the migration route that bypasses the high altitudes of the Himalayas and the Karakoram . Since the barnacles were neither protected in their breeding grounds nor on their migration route, their numbers decreased dramatically. In 1964 200 nun cranes were still wintering in the national park. Almost 10 years later there were only 76 nuns left. In 2002 a nuncrane was sighted for the last time in Keoladeo National Park. This presumably means that the central Siberian populations have died out.
food
The barnacle crane is an omnivore whose diet includes root tubers, rodents , fish and insects . Animal protein only plays a subordinate role. With the exception of early spring, the barnacle crane is almost exclusively vegetarian. During the breeding season as well as in its wintering quarters, it looks for its food exclusively in wetlands and only extremely rarely in terrestrial habitats. He has only the African Klunker- and the North American this characteristic whooping crane together. The nuns' preferred food is root tubers, which they dig up to a depth of 60 centimeters with their long beaks. Once they have fetched tubers out of the water, nun cranes rinse off the mud with a sideways swipe of their beak. They prefer open terrain with an unobstructed view and also defend their feeding grounds in their winter quarters, which they only give up when winter comes to an end and the migration is imminent. Then they begin to look for food in groups.
Reproduction
The barnacle crane apparently only reaches sexual maturity at the age of six to seven years. They are monogamous birds that enter into a pair relationship that lasts over several reproductive periods.
The remainder of the western population arrives at its breeding grounds when the tundra is almost completely covered by snow and only the southern slopes and stiff banks of the rivers show the first snow-free spots. They are strictly territorial and resolutely defend their nesting territory. In the west, the minimum distance between the nests is 2.5 kilometers, but numerous suitable breeding sites remain unoccupied. In the east of the distribution area, the minimum distance between the nests is slightly smaller and is 1.5 kilometers.
The nests are used for several years. The nest base is a rammed flat platform surrounded by water. The padding consists of dry previous year's stems and branches of sedges, as well as green plant material. The built-up plant material comes from the immediate vicinity, so that perennial nests are surrounded by a free water surface of five to 10 meters in diameter.
The time of oviposition depends on the geographical distribution. It begins in the last days of May and continues until mid-June. Sandhill cranes farther south are the earliest to begin laying eggs. The full clutch consists of two eggs. Of all crane species, nun cranes have the darkest eggs together with the black-necked cranes of the Tibetan highlands. This is considered an adaptation to the climate in their breeding area. Subtropical crane species have white eggs because the white shell regulates the sun's heat better. It prefers to breed the female, the male usually shedding it for a short time during the day. The breeding female usually sits flat on the nest with her head low. It only raises its head in danger. During the day, the male often eats and rests far away from the nest, but maintains voice contact with the brooding female. During the night, however, the male stays close to the nest. The breeding period is 27 to 28 days. The hatching process takes over 24 hours, the second chick usually hatches a day and a half after the first chick. The two chicks show very high levels of aggression and fight with each other until one of the two chicks dies. Usually the older chick survives. The aggressiveness towards a sibling does not cease until the age of 40 days.
The young birds fledge after 70–75 days. The greatest weight gain is seen between the nuns' crane chicks between the ages of 10 and 40. However, weight gain can still be seen in the 18th week of life.
Barnacle cranes can get very old. A female barnacle crane caught in the wild lived at the Philadelphia Zoo for more than 61 years .
Duration
The overwintering crane population in China - 95% of the total population - are affected by the hydrological changes caused by the construction of the Three Gorges Dam . The population of only 2900 to 3000 animals is falling rapidly. Around 200 animals live in captivity.
Cross-state conservation measures began as early as the early 1970s. Protection zones have been established in various places in Russia, Pakistan, China and India, which the barnacle crane uses during its migration. However, the long trails on which black sandals are illegally hunted, especially in Pakistan and Afghanistan, pose a particular challenge in preserving this species.
Nowadays, nun cranes are specifically bred in zoos. The breeding centers include the International Crane Foundation's enclosures in the United States, the Oka State Nature Reserve in Russia, the Beijing Zoo in Beijing and the Walsrode Bird Park in Germany. When it comes to keeping the barn crane is the potentially most irritable species, which requires certain precautionary measures. The potential for aggression is not only evident towards keepers, but also makes it difficult to form suitable breeding pairs. Often, zoos are forced to keep each other in separate enclosures so that they do not die. The first nunnery to be born in captivity was only raised in the International Crane Foundation's enclosure in 1980.
The barnacle crane is considered so threatened that there is a Global Animal Survival Plan for this species. This is an attempt to ensure worldwide cooperation in the conservation efforts around the barnacle crane.
Systematics
The barnacle crane is usually assigned to the genus Grus within the crane family. Anatomical features indicate a relationship with the African rock crane . However, DNA studies show that the barnacle crane is very different from the other species of crane and may have to be assigned to its own genus.
Cultural meaning
The Yakuts are among the peoples who particularly venerate the barnacle crane . The tribal order practiced until the 11th century gave each tribe a bird name. The nun crane was the symbol of all Yakut tribes. One of the most popular dances of this Turkic people is the so-called dance of the white crane .
One of the earliest known images of the nunnery is a drawing by Mansur (1569–1627), a painter at the court of the Mughal ruler Jahangir . The drawing is unusually detailed and also shows that the red of the face also includes the nostrils and the base of the long beak. The first scientific description comes from the German doctor and naturalist Peter Simon Pallas , who traveled to the Russian Empire in the 18th century.
supporting documents
literature
- David H. Ellis , George F. Gee , Claire M. Mirande (Eds.): Cranes: Their Biology, Husbandry, and Conversation. Hancock House Publishers, Blaine 1996, ISBN 0-88839-385-7 .
- Peter Matthiessen : The kings of the air - traveling with cranes. Fischer Taschenbuch Verlag, Frankfurt am Main 2010, ISBN 978-3-596-18195-7 .
- RL Potapov, VE Flint (ed.): Handbook of the birds of the Soviet Union. Volume 4: Galliformes, Gruiformes. Aula Verlag, Wiesbaden 1989, ISBN 3-89104-417-8 .
Web links
- International Crane Foundation's Siberian Crane page
- BirdLife International: Species Factsheet - Leucogeranus leucogeranus
- Snow cranes
- Craneworld - image of the nuncrane
- Leucogeranus leucogeranus in the endangered Red List species the IUCN 2008. Posted by: BirdLife International, 2008. Accessed January 31 of 2009.
- Videos, photos and sound recordings of Grus leucogeranus in the Internet Bird Collection
Individual evidence
- ↑ Matthiessen, p. 138.
- ^ Potapov & Flint, 1989, p. 240.
- ^ Potapov & Flint, 1989, p. 241.
- ↑ Matthiessen, p. 149.
- ^ Potapov & Flint, 1989, p. 247.
- ^ Potapov & Flint, 1989, p. 247.
- ^ Potapov & Flint, 1989, p. 249.
- ↑ Matthiessen, p. 133.
- ↑ Ellis et al., P. 273.
- ↑ Ellis et al., P. 27.
- ^ Potapov & Flint, 1989, p. 244 and p. 245.
- ↑ Matthiessen, p. 135.
- ↑ Matthiessen, p. 148.
- ↑ Ellis et al., P. 3.
- ↑ Matthiessen, p. 148.
- ^ Potapov & Flint, 1989, p. 245.
- ^ Potapov & Flint, 1989, p. 246.
- ^ Potapov & Flint, 1989, p. 246.
- ^ Potapov & Flint, 1989, p. 246.
- ↑ Matthiessen, p. 45.
- ^ Potapov & Flint, 1989, p. 247.
- ^ Potapov & Flint, 1989, p. 247.
- ↑ Ellis et al., P. 82 and p. 83.
- ↑ Ellis et al., P. 25.
- ↑ Ellis et al., P. 274.
- ↑ Ellis, p. 27.
- ↑ Matthiessen, p. 42.
- ↑ Matthiessen, p. 143.
- ↑ Matthiessen, p. 143.
- ↑ Ellis et al., P. 178 and p. 179.
- ↑ Ellis et al., P. 3.
- ↑ Matthiessen, p. 28 and p. 29.
- ↑ Matthiessen, p. 29.
- ↑ Matthiessen, p. 134.