House sailor
| House sailor | ||||||||||
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House sailors ( Apus affinis ) over India |
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| Scientific name | ||||||||||
| Apus affinis | ||||||||||
| ( JE Gray , 1830) |
The house sailor ( Apus affinis ) is a species of bird and with a length of 12 centimeters it is the smallest member of the genus Apus , which also includes the common swift , which is widespread in Europe . Compared to the other representatives of this genus, it looks clumsy, the trunk is relatively strong, the wing tips are more blunt than in other types of sailor. In Africa south of the Sahara and in India the little swift is widespread. Isolated, isolated occurrences exist in North Africa, Iran and Pakistan . Like all sailors, house swifts hunt for insects or arachnids in the air .
The house sailor is also referred to as the stubby sailor or the white humpback sailor , but the latter term is misleading, as it is also used for the Cape sailor . Another source of confusion is that the English name House Swift is mostly used for the Malay sailor and less often for the house sailor, which in English is mainly referred to as Little Swift , ie "little sailor".
description
Appearance
The predominantly black body is relatively broad and stocky, the wings are quite short and blunt and less sickle-shaped compared to other species of this genus. A large, white, roundish throat patch is striking, which is unmistakably gray spotted in the worn plumage. The top of the head is gray-brown, the neck black-brown. The rest of the upper side is dark brown with the exception of the striking white rump . The underside is predominantly deep black, somewhat paler and lighter at the transition to the throat. The lower coverts of the tail show a pale gray. Both sexes look the same. The plumage of the young birds looks rougher, less shiny and resembles that of the freshly molted adult birds; these features are most pronounced on the feather feathers of the wings.
The wing length is approximately 137 millimeters, the weight is between 18 and 30 grams, an average of 25 grams. All four toes of the short, strong brace feet are directed forward.
Differentiation from similar species
In addition to the somewhat clumsy shape, the white throat patch and the white rump, as well as the tail shape, which is atypical for sailors, are good identifying features. The tail is cut straight when closed, and rounded when open. The Malay Swift , which is closest to the house swift in appearance, is darker, especially on the head. The house sailor also differs from other sailors because of its small size. Its flight appears less graceful and powerful than that of its close relatives, the gliding phases are comparatively long.
voice
The house sailor is very happy to shout, usually you can hear a rough, quickly performed trill that sounds like "der-der-der-dit-derdiddidu" . A wide range of thin calls can be heard especially near the nesting site.
Spreading and migrations
The isolated occurrences of the Western Palearctic are located in the Banc d'Arguin National Park , in Morocco on the Atlantic coast south to the 30th parallel, in the Moroccan interior in the High and Middle Atlas , and very scattered in Algeria and Tunisia . In the eastern Mediterranean there are isolated occurrences in the extreme east and southeast of Turkey , in north and central Israel and in the West Bank . The comparatively sparse populations in the Western Palearctic show signs of expansion, even if the populated area of the species in Tunisia now seems to be shrinking after expansion in the first half of the 20th century. It is also believed that Spain was recently colonized. In addition to a few other sightings, five house swifts were sighted in 1996 at a breeding site for the Cape Swift near Tarifa on the southern Spanish coast, whose behavior made an attempt at breeding appear likely. A small deposit currently exists in the port of Chipiona in Andalusia .
The most important occurrence of the house swift is in Africa south of the Sahara, where it can be found everywhere with the exception of the driest areas. In Africa, populations have increased enormously in the course of the 20th century due to its habituation to habitats in the vicinity of humans.
Further deposits are located in the southwest of the Arabian Peninsula , further east in Iran , Afghanistan , Pakistan and above all in India south of the Himalayas , from Punjab in the west to the Bengal in the east and Sri Lanka in the south. The house sailor is also very common in many cities in India.
Especially in the tropics, the house sailor is a resident bird , only in the extreme north and south of the range it is partially a migratory bird . Only the Turkish population seems to completely leave the breeding area between October and February. The house sailor is also a summer visitor in Tajikistan , Uzbekistan and Turkmenistan . The populations only seem to move away in part, in the Middle East an absence is reported in some breeding areas in mid-winter, in other places a more or less strong decrease in populations.
habitat
The house sailor can be found in the warm , temperate , subtropical and equatorial latitudes. Arid areas are largely avoided, although the subspecies A. a. galilejensis breeds sparsely in areas such as the Dead Sea .
In large parts of its range, it breeds only in the vicinity of humans and is seldom seen far from their settlements. In many African and Indian cities it is a familiar sight and its calls are a familiar background noise. In some areas the house swift also uses the natural breeding grounds in ravines, rocks and mountain flanks. To search for food, distances of 15 to 20 kilometers are covered from the breeding site and so one can find breeding sites in a wide variety of biotopes , often at great heights, for example up to 3000 meters in Kenya . In South Africa it has been observed that the house sailor avoids high-altitude grazing land , possibly due to the competition of the house martin in these areas.
Reproduction
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In Africa, the duration and beginning of the breeding season vary widely depending on latitude and climate. The house sailor breeds year-round in the tropical rainforest , but only in June in Chad . In East Africa , the breeding season coincides with the rainy season. Other examples of the laying time in Africa are September to May in Zimbabwe or October and March to April in Zambia . In South Africa, the breeding season lasts from August to April with a share of 66 percent between September and November. In India the nominate form breeds all year round except in the coldest months from November to February, the subspecies A. a. singalensis mainly from March to July.
The house sailor breeds in relatively small colonies of up to 30 breeding pairs. Two to three birds can lay the eggs in the same nest. Abandoned swallow nests of the genus Hirundo can be taken over, and such nests have also been forcibly taken over. The house sparrow , however, the little swift can occasionally be displaced. Nests on buildings with a roof overhang are typical . The nests are stable, look messy on the outside, but are evenly and neatly built inside. The nest hollow forms a hemisphere, mainly vegetable components are used as material, especially grass and thin twigs, but down and feathers are also used; the components are stuck together with saliva.
The clutch consists of one to three eggs that are approximately 22.5 x 14.5 millimeters in size. Eggs are usually laid over 4 to 5 days, within a breeding colony the laying period extends over about 10 days. The incubation period lasts 22 to 24 days, initially the eggs are incubated 90 percent of the time of the day, both partners participate. In the case of second broods, the eggs are laid again after the first young has fledged.
Inventory and inventory development
The house sailor can be found in a fairly large area with an estimated size of 10 million square kilometers. Worldwide data on the population and its development are not available, but there are indications of an increase in the population. However, this does not apply to the population in Turkey, which is estimated at 900 to 2500 breeding pairs. There it is assumed that the population will decline, one possible cause being the construction of a dam .
Systematics
House swifts and Malay swifts ( Apus nipalensis ) were originally considered one species. However, since the breeding areas overlap without hybridization occurring, most authors now see the Malay Swift with its four subspecies as an independent species.
There are 6 subspecies of house sailors:
- A. a. galilejensis : This subspecies occurs in a broad strip from North Africa eastwards through the Middle East to Pakistan , also south of the Sahara in eastern Sudan , Ethiopia and northwest Somalia . The above description of the species mainly refers to this subspecies, which is the palest of all subspecies.
- A. a. affinis : The nominate form colonizes India on the eastern border with Pakistan and south of the Himalayas , as well as eastern Africa from southern Somalia to northern Mozambique and the islands of Pemba and Zanzibar . The plumage is generally a bit blacker than that of galilejensis , the contrast between body and head is less strong.
- A. a. aerobates : The subspecies has an extensive range in Africa, from Mauritania to West Africa, east to Somalia and south to Transkei in South Africa. The plumage is even darker than that of affinis , especially on the wings and tail.
- A. a. theresae : The south of Africa, from Angola in the west to the south of Zambia and South Africa are colonized by this subspecies. This is similarly pale as galilejensis , but differs from this subspecies by the darker lower tail feathers.
- A. a. bannermani : This subspecies is native to the islands in the Gulf of Guinea . It represents the darkest race and can be recognized by its striped throat.
- A. a. singalensis : This subspecies colonizes southern India and Sri Lanka . The plumage is blacker than that of the affinis subspecies , which is more widespread in India , especially on the head and the upper coverts of the tail. The tail has a small crotch.
literature
- Phil Chantler, Gerald Driesses: 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 ; Pages 239-242; see literature
- ^ Avibase entry: Haussegler ( Apus Affinis ) Gray, JE, 1830
- ^ RE van der Vliet, CC Moore: White-rumped sailors: News from the Iberian Peninsula . In: Der Falke 46: 130, edition 05/1999, ISSN 0323-357X
- ↑ Rare Birds in Spain: Little Swift Apus Affinis. Retrieved April 29, 2014
- ↑ BirdLife International: Species Factsheet - Little Swift ( Apus affinis )
- ↑ www.biothemen.de: Problematic dam construction - The Turkish dam project and its effects on the environment and the local population
Web links
- Apus affinis in the endangered Red List species the IUCN 2008. Posted by: BirdLife International, 2008. Accessed on 12 November, 2008.
- Videos, photos and sound recordings about Apus affinis in the Internet Bird Collection
- House sailor's feathers
