Derby Arassari
| Derby Arassari | ||||||||||
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Derby-Arassari, drawing by John Gerrard Keulemans from 1891 |
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| Aulacorhynchus derbianus | ||||||||||
| Gould , 1835 |
The Derby Arassari ( Aulacorhynchus derbianus ), also known as the blue-naped arassari , is a species of bird in the toucan family. Due to the long and slightly curved beak in relation to body size, it can be clearly identified as a representative of this family. The species occurs in South America, several subspecies are described. The IUCN classifies the Derby-Arassari as safe ( least concern ). Exact population figures are not available, but it is not a common species in its extensive distribution area.
Appearance
The body length of fully grown Derby Arassaris is 36 to 42 centimeters. The males of the nominate form reach a wing length between 12.9 and 14.7 centimeters. The tail length is between 12.1 and 13.7 centimeters. The beak has a length between 8.7 and 10.0 centimeters. Females are slightly smaller and there is no conspicuous sexual dimorphism . Only the beak is significantly smaller at 6.4 to 8.5 centimeters.
Adult birds are dark green on the top of the body and light green on the underside of the body. Only in the neck area does the green change into a blue-green in some individuals. The trunk is yellow-greenish, the tail has a chestnut-brown tail band. The throat is white, the sides of the throat become bluish. The front cheeks and a narrow rein stripe are also light blue. The underside of the body is otherwise light green, with individuals often having white feathers on the belly. The long beak is slightly curved, the upper beak ends in a point. A white band spans the base of the beak, otherwise the beak color is individually different red and black. Some individuals have an almost black beak. The featherless facial skin is brown to pale red-brown. The eyes are amber to dark red-brown. The feet and legs are gray to olive in color.
Young birds have a slightly duller plumage, the yellow tones in their plumage are less pronounced.
In its area of distribution, the Derby Arassari can be confused with the Laucharassari and the Gray-billed Arassari . It can be distinguished from these two species because it is not plumed red on the trunk and the under tail-coverts are green. The species also differ in their altitude distribution, so that they can only rarely be observed together.
Distribution area
The Derby Arassari occurs in Andean forests from southern Colombia to Ecuador , Peru and northwest Bolivia . Isolated from this, there are some distribution areas in mountainous regions of Bolivia, Venezuela and Brazil . Usually the Derby Arassari occurs at altitudes between 800 and 1600 meters. In the Andes, it is occasionally observed at altitudes over 2000 meters.
Way of life
Very little is known about the Derby Arassari's way of life. Basically he is an inhabitant of moist subtropical rainforests. It is also found in higher-lying tropical forests with a rich growth of bromeliads and mosses. In some regions of its distribution area it still lives in transition zones to the temperate forest.
The Derby Arassari is generally not very popular. It is observed singly, in pairs or in small flocks that rarely contain more than ten individuals. He looks for his food mainly in the treetops. It mainly consists of fruits, but insect remains have been found in three out of 18 stomachs. The reproductive behavior has not yet been investigated. However, it is known that the breeding season falls between June and October.
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 Factsheet about the Derby Arassari ,
- Aulacorhynchus derbianus inthe IUCN Red List of Threatened Species 2013.1. Listed by: BirdLife International, 2012. Retrieved October 23, 2013.
Single receipts
- ↑ Blue-naped macaws at Avibase, accessed November 9, 2018.
- ↑ BirdLife Factsheet on the Derby Arassari , accessed December 28, 2010
- ↑ Lantermann, p. 110
- ↑ Short et al., P. 333
- ↑ Short et al., P. 335