Common swift (Apus apus)
|Also known as:||European swift, swift|
|Size||Length: 16 - 17 cm (2)|
Wingspan: 38 - 40 cm (3)
|Weight||36 - 52 g (2)|
The common swift is classified as Least Concern on the IUCN Red List (1).
The most aerial of birds, the common swift (Apus apus) is renowned for its superb flying ability, favouring a life spent almost entirely on the wing. This bird is unique in its ability to stay airborne for extended periods, spending up to nine months aloft outside the breeding season. The common swift performs most activities in the air, including feeding, preening, playing, sleeping and mating and, in fact, it only lands to feed its young or roost (3) (4) (5) (6).
The common swift’s body is perfectly developed for flying. The tail is deeply forked and the sickle-shaped, sharply-pointed wings are narrow but long, enabling it to make rapid, sharp turns in the air whilst hunting flying insects. The feet are specially adapted to grasp onto vertical surfaces, meaning that when the common swift roosts, it can occupy habitats like chimneys and building eaves, which other birds cannot (4).
The common swift’s plumage is plain sooty-brown, but appears black in flight (7). The tail, crown and underparts are black-brown, and there is a small off-white throat patch. The male and female common swift are similar in appearance, but the juvenile is dark black, except for white fringes on the forehead and a larger, well-defined white throat-patch (2).
The common swift has an extremely large range that includes much of Europe, Asia and Africa. A migratory species, it breeds at northern latitudes and travels to sub-Saharan Africa before the onset of the northern winter (2).
Two subspecies of the common swift are currently recognised. Apus apus apus breeds across western and northern Europe, south-east towards Iran, and winters mainly from the Democratic Republic of Congo and Tanzania, south to Zimbabwe and Mozambique. Apus apus pekinensis breeds from Iran, east through the western Himalayas to Mongolia and northern China, and winters mainly in Namibia and Botswana (2).
The common swift naturally breeds in holes in caves or hollows of trees. However, nowadays this adaptable species mostly nests in towns and villages in holes in walls or under the eaves of houses. It has little fear of humans and will also breed in artificial nesting boxes attached to buildings (5).
The common swift travels large distances each day to feed over a variety of habitats that includes forests, open plains, deserts and steppe (2).
A gregarious species, the common swift forages in large flocks for a variety of small flying insects. These feeding groups may be frequently heard ‘screaming’, in a display that probably serves to advertise the presence of the group to other swifts. By encouraging more swifts to join the group, there will be larger numbers of birds seeking out the best feeding areas, thereby benefiting all the individuals (6). It is its dependency on insects that explains why the common swift must migrate, as during the northern winter insects become scarce, whereas they are in abundance at this time in the tropics (8).
Breeding common swifts return to the same colonies to mate each year, usually around the start of May. Pairs may breed together for many years, but if one partner dies, its place is immediately taken by another. A clutch of two or three eggs is laid in a cup-shaped nest, made of feathers and vegetation glued together with saliva. The site of the nest is usually chosen by the male swift. Incubation duties are shared equally by the male and female and last for 19 or 20 days. Both adults feed the young for the 42 or so days that they are in the nest, with the adults flying as far as 560 miles each day whilst foraging (2) (3).
While nesting, the common swift can be exposed to sustained periods of cold weather. However, a layer of fat insulates the body and its slow metabolism prevents excessive energy use, enabling the swift to survive such conditions. Furthermore, swift chicks can survive long periods of cold weather and starvation by entering a state of torpor (8), a coma-like condition in which its metabolism slows to almost nothing. For a bird of its size, the common swift can live for a remarkably long time, with some individuals known to live for as long as 21 years (3).
The common swift is widespread and abundant and not currently considered at risk of extinction (9). In Europe, which comprises half of its global range, the breeding population is estimated at over 700,000 breeding pairs (10). However, the common swift population is thought to be in a fairly large decline owing to the loss of nest sites through building improvements or demolition (9).
This species nests almost exclusively in old buildings constructed in the early half of the 20th century, as modern building techniques and materials deny the common swift access to eaves and wall cavities for nesting. A tendency to demolish or refurbish old buildings such as warehouses and factories, which are often converted to modern apartments, also leads to a loss of nesting sites (11).
The common swift readily breeds in artificial nesting boxes, meaning homeowners and building developers can help to maintain swift populations in urban areas. Attaching nest boxes is a cheap and easy way of ensuring the preservation of this species (11).
More information on the common swift and other bird species:
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- Incubation: the act of incubating eggs, that is, keeping them warm so that development is possible.
- Steppe: a biome (or subdivision of the Earth’s surface) that is composed of a swathe of temperate grassland stretching from Romania to China. Natural grassland with low rainfall.
- Subspecies: a population usually restricted to a geographical area that differs from other populations of the same species, but not to the extent of being classified as a separate species.
IUCN Red List (March, 2011)
- del Hoyo, J., Elliot, A. and Sargatal, J. (1999) Handbook of the Birds of the World. Volume 5: Barn-owls to Hummingbirds. Lynx Edicions, Barcelona.
Commonswift.org (March, 2011)
BBC Wildlife Finder - Common swift (March, 2011)
Birds of Britain - Common swift (March, 2011)
BirdGuides - Common swift (March, 2011)
RSPB - Common swift (March, 2011)
- Perrins, C. (2009) The Encyclopedia of Birds. Oxford University Press, Oxford.
BirdLife International (March, 2011)
- Burfield, I. and van Bommel, F. (2004) Birds in Europe: Population Estimates, Trends and Conservation Status. BirdLife International, Cambridge, UK.
Swift-conservation.org (March, 2011)