Yolk toucan
| Yolk toucan | ||||||||||
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Yolk toucan, nominate form |
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| Systematics | ||||||||||
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| Scientific name | ||||||||||
| Ramphastos vitellinus | ||||||||||
| Lichtenstein , 1823 |
The channel-billed toucan ( Ramphastos vitellinus , too) Zitronentukan (subspecies Ramphastos vitellinus citreolaemus ) Arieltukan (subspecies Ramphastos ariel vitellinus ) or Kulmtukan (subspecies Ramphastos vitellinus culminatus called) is a species of bird from the family of toucans (Ramphastidae). It occurs exclusively in South America. It is a large toucan, it can only be confused with the even larger white-breasted toucan . However, the two types also differ in their repertoire of calls. Several subspecies have been described for the yolk toucan, some of which differ significantly in terms of face, beak and breast color.
The IUCN classifies the yolk toucan as harmless ( least concern ). There is no information on the world population, but it is said to be relatively common. Since yolk toucans are more frequently in the bird trade, they have been listed in Appendix II / B of the Washington Convention on the Protection of Species since 1992 .
Appearance
Dimensions
Yolk toucans reach an average body length of 48 centimeters. The males of the nominate form have a wing length between 18.0 and 20.6 centimeters and a tail length of 15.2 to 17.2 centimeters. The beak is between 12.0 and 14.4 inches long. The females are a bit smaller. Their wing length is between 18.3 and 20.0 centimeters, the tail measures 14.6 to 16.8 centimeters and the beak has a length of 9.9 to 12.0 centimeters.
Nominate form
Adult yolk toucans of the nominate form have a shiny upper side of the body, the wings, the tail and the upper ear covers and the upper side of the neck are black. The upper tail-coverts are bright red, the chin and sides of the neck are white. The white turns into a bright yellow to orange in the middle of the chest. The feathers on the front chest have a black base and end in a strong red. The sides of the chest, the underbust, the flanks and the belly are black, but a little less shiny than on the upper side of the body. The under tail-coverts are bright red.
The beak is long, the upper beak is clearly curved and ends in a sharp point. The beak base spans a narrow black band directly at the base. The back of the upper beak is slightly raised and widened, which has led to the English name Channel-billed Toucan . It has small vertical bulges on the sides of its beak. The base of the beak is black, followed by a light blue to dark blue stripe that runs across the upper and lower beak. The rest of the beak is black. The bare skin of the face is pale blue and slightly darker around the eye. The iris is brown, some individuals have a white eye ring.
Young birds are a little more dull, their black plumage looks sooty.
More subspecies
- The subspecies Ramphastos vitellinus citreolaemus ( Gould , 1854), which occurs in northern Colombia and northwestern Venezuela, has pale yellow markings on the throat and chest. The vertical stripe on the beak is greenish-yellow and not bluish as in the nominate form. The beak is black with a yellow ridge band reaching to the tip. The lower bill has a yellowish tip. The red chest band is very narrow. The upper tail-coverts are pale yellow. It is slightly larger than the nominate form.
- The subspecies Ramphastos vitellinus culiminatus ( Gould , 1854), which occurs in Colombia east of the Andes and in southwest Venezuela as well as in northwest Bolivia, has a white throat, the yellow markings in the region from throat to front chest are sometimes completely missing. The red chest band is even narrower than that of the subspecies R. v. citreolaemus . The upper tail covers are golden yellow. The vertical band at the base of the beak is not completely blue on both the upper and lower stripes, but also has yellow and orange colored areas. The back of the beak is greenish-yellow and brightens into a strong yellow at the tip of the beak. In this subspecies, too, the lower beak has a yellowish tip.
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- The subspecies Ramphastos vitellinus ariel ( Vigors ) , which occurs in Brazil south of the Amazon, is similar to the nominate form, as it also has red upper tail-coverts, the breast is orange in color and the back of the beak is black. It differs from R. v. vitellinus due to the very intense golden-orange tone on the front face and chest. The chest band is deep red and as wide as or wider than in the nominate shape. The vertical beak band is yellow to orange-yellow and not blue as in the nominate form. The bare facial skin around the eye is also deep orange.
In the past, the subspecies were sometimes described as separate species. However, all four subspecies willingly crossbreed in areas where their ranges overlap. These hybrid populations are colored very variably and in some cases have also been described as independent subspecies. R. v. theresae , R. v. pintoi and R. v. osculans are now classified as descendants of two subspecies and are no longer viewed as an independent subspecies.
In the east of Brazil there is a population isolated from the rest of the yolk toucan population, traditionally belonging to the subspecies R. v. ariel is assigned. However, detailed genetic studies have shown that this population has been isolated for a very long time and may be either a separate subspecies or even a species of its own.
Distribution area
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The distribution area of the yolk toucan is very large and extends from 11 ° north latitude to the tropic of the tropics . Specifically, the yolk toucan occurs in the north, north-east and east of Colombia, in the north-west of Venezuela, in Bolivia, Guyana and in the east and south-east of Brazil. It is absent in dry or deforested areas. Its altitude ranges from sea level to altitudes of 1140 meters in Colombia, 1700 meters in Venezuela, 1200 in Ecuador and Peru, 1650 meters in Bolivia and 1000 meters in Brazil.
habitat
The yolk toucan usually lives in different forest types in the lowlands. It lives particularly in forest areas that are close to rivers and lakes. In forests where selective logging has taken place, it is still rare after eight to twelve years. It inhabits forest clearings, gallery forests and also occurs in tropical humid rainforests along the Andes, which have a rich growth of bromeliads , mosses and epiphytes. In some regions, such as the high altitudes in Venezuela, its habitat also extends to subtropical forests. It is also found in some drier forest areas in Bolivia.
Food and foraging
The yolk toucan searches for food individually, in pairs or in small groups of up to 15 individuals. Unlike the white-breasted toucan , it does not aggressively drive other bird species from its food trees and can occasionally even be observed in company with the white-breasted toucan. It finds its food mainly in the treetops. Occasionally it even comes to the ground to eat fallen fruit or to look for small insects. As with the giant toucan and white-breasted toucan, animal food plays a larger role in its food spectrum. It deliberately robs the nests of starlings of the genus Cacicus and screechers as well as other bird species and eats their eggs and young birds. He even takes sleeping bats, as well as frogs and toads. It also eats swarming termites as well as nectar and flowers. Figs and nuts from various trees also play a role in its diet. Both fruits and birds or mice are first thrown into the air, then caught and swallowed. Fruits that are too big for the toucan to swallow whole are held in place with the foot and pieces are then torn out. With its excrement, the bird excretes the seeds of numerous fruits and thus plays an important ecological role in the reproduction of trees and bushes. It takes water from the stem axis of bromeliads. However, when it rains it occasionally sits with its beak open to catch water.
Reproduction
The territory of a pair of yolk toucans is estimated to be 40 hectares, but nesting caves are sometimes only 200 meters apart, which is an indication that yolk toucans do not always find suitable nesting caves. Yolk toucans do not build their own burrows, but rely on natural tree hollows as nesting sites. If they successfully raise young birds in a tree cavity, it is likely that they will also use this tree cavity in the next breeding season.
Mated birds spend a lot of time in their nest box before they lay eggs. They aggressively defend the immediate vicinity of their brood cavity. In the case of yolk toucans kept in captivity, experience has shown that the offspring of the previous year must also be removed from the aviaries, otherwise the breeding birds will kill them. Courtship behavior includes feeding the female by the male. The breeding season varies depending on the geographical latitude. In Guyana, for example, it falls between November and April, while in eastern Venezuela it falls between February and July.
The clutch consists of two to four eggs. These are white-skinned and weigh an average of 16.4 grams. Both parent birds sleep in the brood cavity at night and both are involved in the brood, but the female usually breeds for a longer period of time. The breeding season is 16 to 18 days. After hatching, the eggshells are removed from the nest cavity by the parent birds. Newly hatched nestlings are bare and bluish and their eyes are still closed. Their weight corresponds to about five percent of the weight of an adult yolk toucan. Feed both parent birds. Animal food plays a major role in the rearing of young birds. The young birds fly out at an age of 37 to 45 days.
Monkeys and snakes eat nestlings. Therefore yolk toucans hate these species. The great hooded eagle and the great horned owl hunt adult yolk toucans.
Yolk toucans and humans
Yolk toucans are still hunted by indigenous South American peoples as a food resource. The beak is processed in South American folk medicine and they play a role in the myths of South American peoples. The Brazilian emperors Peter I and Peter II wore ceremonial robes made from the breast feathers of the yolk toucan.
According to current knowledge, the first yolk toucans were kept in the Amsterdam Zoo as early as 1853. These were ariel toucans. The nominate form was first introduced to England in 1872. The ariel toucan in particular is still kept in zoos and bird parks, as this subspecies with its yellow-orange throat and chest is one of the most attractive representatives of the real toucans .
supporting documents
literature
- Werner Lantermann: Toucans and Arassaris. Filander Verlag, Fürth 2002, ISBN 3-930831-46-5
- Lester L. Short and Jennifer FM Horne: Toucans, Barbets and Honeyguides - Ramphastidae, Capitonidae and Indicatoridae . Oxford University Press, Oxford 2001, ISBN 0-19-854666-1
Web links
- BirdLife International: Species Factsheet - Channel-billed Toucan ( Ramphastos vitellinus )
- Ramphastos vitellinus inthe IUCN Red List of Threatened Species 2013.1. Listed by: BirdLife International, 2012. Retrieved October 23, 2013.
Single receipts
- ↑ BirdLife International: Species Factsheet - Channel-billed Toucan ( Ramphastos vitellinus ) . Retrieved December 23, 2010.
- ↑ Short et al., P. 414
- ↑ Lantermann, p. 175
- ↑ Short et al., P. 416 and p. 417
- ↑ Short et al., P. 417
- ↑ Short et al., P. 417
- ↑ Short et al., P. 417
- ↑ Short et al., P. 418
- ↑ Short et al., P. 418
- ↑ Short et al., P. 418
- ↑ Short et al., P. 417
- ↑ Lantermann, p. 178
- ↑ Lantermann, p. 179