Cape sailors
| Cape sailors | ||||||||||
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Cape Swift ( Apus caffer ) |
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| Systematics | ||||||||||
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| Scientific name | ||||||||||
| Apus caffer | ||||||||||
| ( Lichtenstein , 1823) |
The Cape Swift ( Apus caffer ) is a comparatively small member of the sailor family and is a close relative of the common swift, which is widespread in Europe . Like all sailors, the Cape Swift hunts for insects and arachnids in the air . Originally, the range of this bird was art in Africa south of the Sahara limited, only in recent years the white-rumped swift nests in Morocco , in southern Spain and in a few pairs in Portugal. The Cape Swift is also rarely referred to as the White Pebble Swift , but it shares this alternative name with the House Swift .
description
The Cape Swift has the typical shape of a sailor, i.e. a slim trunk and comparatively long, sickle-shaped wings, whereby these characteristics are even particularly pronounced. The tail is long and deeply forked when open, but a characteristic of this species is that the tail is kept closed for long periods of time in flight and looks like a sharp needle.
The bird's plumage is largely black, the striking white throat patch forms a clear contrast. The also white rump, to which the species owes its alternative German and English name ( white-rumped swift ), can only be seen in flight when you see the bird from the side. Both sexes of the Cape Sailor look the same.
The contrast between black and white clearly distinguishes the Cape Swift from almost all other sympatric species of sailor , with the exception of the Horus and house swift . The Horus swift can be distinguished by its larger, more massive appearance, the house swift can be recognized by its typical tail, which is rectangular when closed and only slightly rounded when open.
The vocalizations are not very noticeable, the Cape Swift is quite quiet, especially in comparison to the house swift. Mostly one hears a chirping trill that sounds like " sip-sip-sip-siep-sip-sip ", is deeper than that of a house sailor and reminiscent of the vocalizations of bats.
Spreading and migrations
The distribution area south of the Sahara is extensive, but quite fragmented. In East Africa, the Cape Swift is the most common sailor in rural areas. Also in the south of Africa, especially in Mozambique , there are abundant occurrences, whereby the populations are increasing, which is mainly due to the additional nesting places for swallows created by bridge construction , which the Cape Swift parasitizes . In western Africa the extensive breeding area is far more fragmented.
Only recently the distribution area was extended to the west of the Palearctic , but where it is limited to smaller, mostly isolated occurrences in Morocco and southern Spain. At the moment there is an increase in the population and an expansion of the area to the north and northwest on the Iberian Peninsula. Individual breeding sites are also known from Portugal.
The birds of the Western Palearctic are probably migratory birds , but this is only certain for the Spanish population. The winter quarters are unknown. The individuals of the African population south of the Zambezi are also migratory birds. The winter quarters of these birds are also not known for certain; it has been assumed that they are north of the equator. Migrating birds form flocks of up to 100 birds. In the remaining parts of the distribution area, the Cape Swift is a resident bird with some post-breeding dispersal .
habitat
Due to the occupation of nests of other species that breed, especially on bridges and buildings, the nesting sites of the Cape Swift are mainly tied to humans, natural nesting sites are rare. The Cape Swift has a preference for the nests of the red swallow , other swallows and the house swift . The species is found in a wide variety of habitats within its range, from dry savannahs to forests near the equator. The High Atlas is also populated up to an altitude of 2500 meters.
Reproduction
The breeding season for the Cape Swift, which breeds in the southern and northern hemisphere and near the equator, varies greatly depending on the area. The laying time is, for example, in Morocco in July, in Angola from January to February, in August and in October or in South Africa mainly between October and January.
The nesting of swallows or nests of the house sailor is partly done jointly by groups of 4 to 6 birds, which repeatedly cling to the nest entrance while the nest owner is present. Another strategy is to take over a new nest, which has almost reached the usable stage, in the absence of the nest owner, whereby the entrance is made smaller with saliva in order to make it more difficult for the original nest owner to access. Repeated use of a nesting site over 9 years has been proven, with partner loyalty it was 3 years.
Cape Swifts are sexually mature at the age of two. There are two annual broods in parts of the breeding area, three have already been observed in Tanzania . The clutch size is between one and three eggs. Both sexes participate equally in the breeding business. The average breeding season in Tanzania is 21 and the nestling period is 42 days. In South Africa, the observed times were almost 10 percent higher. The breeding success in Tanzania is 76 percent and in South Africa 57 percent.
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
Web links
- Apus caffer in the endangered Red List species the IUCN 2008. Posted by: BirdLife International, 2008. Accessed on 12 November, 2008.
- Videos, photos and sound recordings for Apus caffer in the Internet Bird Collection