Coffee eagle
| Coffee eagle | ||||||||||||
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Coffee eagle |
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| Systematics | ||||||||||||
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| Scientific name | ||||||||||||
| Aquila verreauxii | ||||||||||||
| Lesson , 1831 |
The Black Eagle ( Aquila verreauxii ) is a very large member of the genus True eagle ( Aquila ). The main range of the nowhere common species is in southern Africa. Despite its size and weight, the agile and agile eagle is unmistakable in its area of distribution. Adult birds appear almost uniformly black.
Appearance
The basic color of the plumage of adult birds is black. The seated eagle usually has a narrow, pure white V that closes from the shoulders to the upper back. In the flying bird, this feature is much clearer when viewed from above and forms a clear Y with a very broad base, since the eagle's tail is also pure white. The mighty beak is mostly light gray, towards the tip it becomes darker. The yolk yellow wax skin as well as color elements on the base of the beak, the lower beak and around the eyes contrast strongly with the black basic color . The eagles have rather long feet, which are feathered black down to the toes; the toes themselves are pale yellow, the nails are black.
The reverse sex dimorphism is only weak. Adult females are often a little lighter, more black-brown in color, but it is not always easy to differentiate between the sexes. Females are on average somewhat larger and usually considerably heavier than males.
When viewed from below, flying coffee eagles also look very dark. What is striking is the white wing field that tends towards gray and darkens towards the dark wing tips.
The plumage of young birds differs greatly from that of adults , but is not very variable in itself. Overall, they are much lighter than colored and almost white on the flanks and thighs. The very light upper head with golden yellow shades towards the neck and the rust-brown shoulder girdle are also characteristic of young birds. Depending on their age, young birds are also lighter in flight , in particular the under wing-coverts have a white, sometimes rust-brown mottling. Coffee eagles wear the adult dress at the earliest when they are five years old, but usually only a year later.
measurements and weight
The size of this eagle ranges from 78 centimeters to 90 centimeters. The wing length reaches almost 60 centimeters in the male, in the female it is about 5 centimeters larger. The wingspan of very large females can be over 210 centimeters. Males weigh between three and a little over four kilograms, the weight of a female can reach six to seven kilograms.
Habitat and Distribution
Coffee eagles mainly inhabit arid and semi-arid rocky hills and mountains, cliffs, gorges and island mountains . They occur at altitudes of over 5000 m .
Coffee eagles are distributed in fragmented occurrences from the southern edge of the central Sahara, South Sudan and the states of eastern Africa southwards to the Cape region. In West Africa it occurs near the coast northwards to central Angola . In addition, there are breeding occurrences with a few pairs in Yemen and Oman , possibly also in the Israeli Negev .
Coffee eagles are true to their place, only young birds migrate .
Food and subsistence
The main prey of this eagle are the rock hyrax ( Procavia sp.) And the bush or steppe hyrax ( Heterohyrax sp.). He also hunts a large number of mammals such as smaller antelopes, hares, rabbits and monkeys as well as birds and turtles. Coffee eagles are rarely seen on carrion .
During the hunt, the species glides low and tries to surprise a prey. Hunting in pairs is often observed, in which one eagle scares up a hyrax colony while the other, coming from behind, tries to hit an animal. Most of the time, the prey is hunted on the ground. Occasionally, it also hunts off other birds of prey.
Social behavior and brood
Coffee eagles live individually or in pairs. Couples show impressive flights over their territory all year round, interspersed with spectacular flight maneuvers. In addition, however, they behave relatively calmly.
The nest is a huge structure made of branches and twigs that can reach a diameter of up to two meters. It is usually around two meters high, but heights of over four meters have been found in clumps that have been used for a longer period of time.
Nest locations are mostly rock platforms, often they are completely or partially covered. The clumps are seldom erected on different trees, for example on acacias or on euphorbias .
As a rule, the clutch consists of two eggs, rarely one or three. The young hatch after an incubation period of 43–47 days. Soon after hatching, the oldest attacks the younger and eventually kills it ( cainism ). Up to 100 days pass before they fled, and after that the young bird is still dependent on its parents for a certain time.
Inventory and inventory development
There are only very vague estimates of the total population of the species, around a few 10,000 individuals. Since the species mainly lives in impassable, mountainous and therefore agriculturally unusable areas, it does not seem endangered at the moment.
Etymology and history of research
René Primevère Lesson described the coffee eagle under its current name Aquila Verreauxii . The type specimen came from the Cape of Good Hope . »Aquila«, a name introduced by Mathurin-Jacques Brisson (1723-1806) as early as 1760, is the Latin word for »eagle«. The specific epithet is dedicated to Jules Verreaux , who collected the hide and sent it to his father in Paris. At the time of the first description, it was in the possession of Adolphe Jean Audenet (1800–1872). The illustration of the coffee eagle was done by Jean-Gabriel Prêtre (1768–1849).
literature
- James Ferguson-Lees and David A. Christie: Raptors of the World. Helm-London 2001, pp. 748-750.
- James A. Jobling: Helm Dictionary of Scientific Bird Names . Christopher Helm, London 2010, ISBN 978-1-4081-2501-4 .
- René Primevère Lesson : Centurie zoologique, ou, Choix d'animaux rares, nouveaux ou imparfaitement connus: enrichi de planches inédites, dessinées d'après nature par M. Prêtre, gravées et coloriées avec le plus grand soin . FG Levrault, Paris 1830 ( online [accessed May 13, 2015]).
- Edward Clive Dickinson, Colin Jones: Some corrections to information provided in Priority! The Dating of Scientific Names in Ornithology ” . In: Zoological Bibliography . tape 2 , no. 2/3 , 2012, p. 75-89 ( online [PDF; 192 kB ; accessed on May 13, 2015]).
Web links
- Birdlife International factsheet
- Aquila verreauxii in the Red List of Threatened Species of the IUCN 2008. Posted by: BirdLife International, 2008. Accessed January 27 of 2009.
- Videos, photos and sound recordings for Aquila verreauxii in the Internet Bird Collection
Individual evidence
- ↑ a b René Primevère Lesson, p. 105.
- ↑ James A. Jobling, p. 52.
- ^ René Primevère Lesson, p. 106.
- ↑ René Primevère Lesson, plate 38.
Remarks
- ↑ According to the Bibliographie de la France , Lesson's work appeared in 16 deliveries. Delivery 1 appeared on March 20, 1830, Delivery 2 on October 2, 1830, Delivery 3 on January 29, 1831, Delivery 6-8 on July 9, 1831, Delivery 13-16 on May 19, 1832. The coffee eagle was part of the shipment 8, which appeared in March 1831. More detailed explanations of the publication dates can be found in Edward Clive Dickinson et al. a. P. 81 table 1.