Alexander sailor
| Alexander sailor | ||||||||||
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| Systematics | ||||||||||
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| Scientific name | ||||||||||
| Apus alexandri | ||||||||||
| Hartert , 1901 |
The Alexander Swift ( Apus alexandri ) is a small sailor that can only be found on the Cape Verde Islands . With a body length of 13 centimeters, it is the second smallest member of the Apus genus after the house sailor . The birds are sociable and can be found in groups of up to 30 individuals. The population is considered stable and the species is classified as not endangered.
The name of the species is said to recall Boyd Alexander , an English ornithologist who led two expeditions to the Cape Verde Islands in 1897 and was murdered near Nyeri in 1910 .
description
Overall, the Alexander Swift is gray-brown in color and is paler in color than all other species of the genus Apus occurring in the western Palearctic . The pale gray patch on the throat is wide but fuzzy. The color of the underside becomes gradually darker from the throat to the gray-brown belly. Both sexes look the same.
The tail of the Alexander Swift has a poorly pronounced fork, the most indistinct of all Apus species. The wing length is approximately 14 centimeters. The wings are relatively short compared to the related species. The comparatively compact shape and the fluttery, feeble-looking flight are the best features to distinguish the Alexandersegler from the related species. In the area of distribution, only the common swift and the pale swift come into consideration, which are easy to distinguish due to their different shape.
The call of the Alexandersegler is higher than that of the Common Swift, less sharp and the individual calls are more clearly separated from each other.
Spreading and migrations
The Alexander sailor, which is endemic to the Cape Verde Islands, occurs there on all islands except Santa Luzia . There is evidence of breeding from the islands of Santiago , Fogo , Brava , Santo Antão and São Nicolau . He is common on Fogo and Brava.
The Alexandersegler is classified as a resident bird , among others in 1995 by CJ Hazevoet . However, it has been observed that the birds may leave the breeding area in the dry season in July.
habitat
The Alexandersegler can be found in all habitats of the archipelago , from sea level to the peaks of the highest mountains, for example at over 2800 meters at Pico do Fogo . The highest brood observed was at an altitude of 1,600 meters.
Reproduction
The nests are located on houses as well as in crevices and caves. The clutch consists of two unspotted, plain white eggs. Otherwise little is known about the breeding business of these birds.
Systematics
In the past , Alexanders and monochrome sailors were sometimes viewed as con-specific. The allocation to the Apus - superspecies , the masonry, monochrome and Nyanza Swift be attributed today of Alexander glider shall due to the unusual color of the eggs as controversial.
No subspecies are distinguished.
literature
- Phil Chantler, Gerald Driessens: A Guide to the Swifts and Tree Swifts of the World . Pica Press, Mountfield 2000, ISBN 1-873403-83-6
Individual evidence
- ↑ This and all information not specially marked are taken from the following source: Chantler, Driessens: A Guide to the Swifts and Tree Swifts of the World . Page 220f, see literature
- ↑ BirdLife International: Species Factsheet - Alexander's Swift ( Apus alexandri )
- ↑ Chantler, Driessens: A Guide to the Swifts and Tree Swifts of the World . Page 25f, see literature
Web links
- Apus alexandri in the endangered Red List species the IUCN 2008. Posted by: BirdLife International, 2008. Accessed October 13 of 2008.