Pacific Swift
Encyclopedia
The Pacific Swift is a small bird
, superficially similar to a House Martin
. It is, however, completely unrelated to those passerine
species, since swift
s are in the order Apodiformes. The resemblances between the groups are due to convergent evolution
reflecting similar life styles.
These birds have very short legs which they use only for clinging to vertical surfaces. The scientific name comes from the Greek
απους, apous, meaning "without feet". They never settle voluntarily on the ground. Pacific Swifts spend most of their lives in the air, living on the insects they catch in their beaks.
Pacific Swifts breeds from central Siberia
eastwards through Asia
. This species is migratory
, wintering south to Australia
. It is a rare vagrant in western Europe, but has been recorded as far west as Norway
and Great Britain
. A 2011 study suggests that the populations can be treated as four distinct species. In this treatment Apus pacificus in the more restricted sense refers to the population that breeds from Siberia to Japan and winters in Southeast Asia east to Tasmania. The breeding population of the Tibetan Plateau is longer tailed and a narrow white rump has been called Salim Ali's Swift
A. salimali. The breeders along the Himalayas of Nepal and Bhutan are treated as Blyth's Swift
(A. leuconyx). Cook's Swift
(A. cooki) which breeds in limestone caves of northern Southeast Asia has a green iridescence, a shallow tail fork and is a short distance migrant.
These swifts build their nests on cliffs, laying 2-3 eggs. A swift will return to the same site year after year, rebuilding its nest when necessary.
Pacific Swifts are similar in size to Common Swift
, and they are black except for a white rump. They can be distinguished from a partially leucistic
Common Swift by the deeper tail fork, longer wings, bigger head and larger white throat patch.
Bird
Birds are feathered, winged, bipedal, endothermic , egg-laying, vertebrate animals. Around 10,000 living species and 188 families makes them the most speciose class of tetrapod vertebrates. They inhabit ecosystems across the globe, from the Arctic to the Antarctic. Extant birds range in size from...
, superficially similar to a House Martin
House Martin
The Common House Martin , sometimes called the Northern House Martin or, particularly in Europe, just House Martin, is a migratory passerine bird of the swallow family which breeds in Europe, north Africa and temperate Asia; and winters in sub-Saharan Africa and tropical Asia...
. It is, however, completely unrelated to those passerine
Passerine
A passerine is a bird of the order Passeriformes, which includes more than half of all bird species. Sometimes known as perching birds or, less accurately, as songbirds, the passerines form one of the most diverse terrestrial vertebrate orders: with over 5,000 identified species, it has roughly...
species, since swift
Swift
The swifts are a family, Apodidae, of highly aerial birds. They are superficially similar to swallows, but are actually not closely related to passerine species at all; swifts are in the separate order Apodiformes, which they share with hummingbirds...
s are in the order Apodiformes. The resemblances between the groups are due to convergent evolution
Convergent evolution
Convergent evolution describes the acquisition of the same biological trait in unrelated lineages.The wing is a classic example of convergent evolution in action. Although their last common ancestor did not have wings, both birds and bats do, and are capable of powered flight. The wings are...
reflecting similar life styles.
These birds have very short legs which they use only for clinging to vertical surfaces. The scientific name comes from the Greek
Greek language
Greek is an independent branch of the Indo-European family of languages. Native to the southern Balkans, it has the longest documented history of any Indo-European language, spanning 34 centuries of written records. Its writing system has been the Greek alphabet for the majority of its history;...
απους, apous, meaning "without feet". They never settle voluntarily on the ground. Pacific Swifts spend most of their lives in the air, living on the insects they catch in their beaks.
Pacific Swifts breeds from central Siberia
Siberia
Siberia is an extensive region constituting almost all of Northern Asia. Comprising the central and eastern portion of the Russian Federation, it was part of the Soviet Union from its beginning, as its predecessor states, the Tsardom of Russia and the Russian Empire, conquered it during the 16th...
eastwards through Asia
Asia
Asia is the world's largest and most populous continent, located primarily in the eastern and northern hemispheres. It covers 8.7% of the Earth's total surface area and with approximately 3.879 billion people, it hosts 60% of the world's current human population...
. This species is migratory
Bird migration
Bird migration is the regular seasonal journey undertaken by many species of birds. Bird movements include those made in response to changes in food availability, habitat or weather. Sometimes, journeys are not termed "true migration" because they are irregular or in only one direction...
, wintering south to Australia
Australia
Australia , officially the Commonwealth of Australia, is a country in the Southern Hemisphere comprising the mainland of the Australian continent, the island of Tasmania, and numerous smaller islands in the Indian and Pacific Oceans. It is the world's sixth-largest country by total area...
. It is a rare vagrant in western Europe, but has been recorded as far west as Norway
Norway
Norway , officially the Kingdom of Norway, is a Nordic unitary constitutional monarchy whose territory comprises the western portion of the Scandinavian Peninsula, Jan Mayen, and the Arctic archipelago of Svalbard and Bouvet Island. Norway has a total area of and a population of about 4.9 million...
and Great Britain
Great Britain
Great Britain or Britain is an island situated to the northwest of Continental Europe. It is the ninth largest island in the world, and the largest European island, as well as the largest of the British Isles...
. A 2011 study suggests that the populations can be treated as four distinct species. In this treatment Apus pacificus in the more restricted sense refers to the population that breeds from Siberia to Japan and winters in Southeast Asia east to Tasmania. The breeding population of the Tibetan Plateau is longer tailed and a narrow white rump has been called Salim Ali's Swift
Salim Ali's Swift
The Salim Ali's Swift , is a small bird, superficially similar to a House Martin. It is, however, completely unrelated to those passerine species, since swifts are in the order Apodiformes...
A. salimali. The breeders along the Himalayas of Nepal and Bhutan are treated as Blyth's Swift
Blyth's Swift
The Blyth's Swift , is a small bird, superficially similar to a House Martin. It is, however, completely unrelated to those passerine species, since swifts are in the order Apodiformes...
(A. leuconyx). Cook's Swift
Cook's Swift
The Cook's's Swift , is a small bird, superficially similar to a House Martin. It is, however, completely unrelated to those passerine species, since swifts are in the order Apodiformes...
(A. cooki) which breeds in limestone caves of northern Southeast Asia has a green iridescence, a shallow tail fork and is a short distance migrant.
These swifts build their nests on cliffs, laying 2-3 eggs. A swift will return to the same site year after year, rebuilding its nest when necessary.
Pacific Swifts are similar in size to Common Swift
Common Swift
The Common Swift is a small bird, superficially similar to the Barn Swallow or House Martin. It is, however, completely unrelated to those passerine species, since swifts are in the separate order Apodiformes...
, and they are black except for a white rump. They can be distinguished from a partially leucistic
Leucistic
Leucism is a condition characterized by reduced pigmentation in animals and humans. Unlike albinism, it is caused by a reduction in all types of skin pigment, not just melanin.- Details :...
Common Swift by the deeper tail fork, longer wings, bigger head and larger white throat patch.