The ridgetop swiftlet (''Collocalia isonota'') is a small bird in the

swift Swift or SWIFT most commonly refers to: * SWIFT, an international organization facilitating transactions between banks ** SWIFT code * Swift (programming language) * Swift (bird), a family of birds It may also refer to: Organizations * SWIFT, ...

family Family (from la, familia) is a Social group, group of people related either by consanguinity (by recognized birth) or Affinity (law), affinity (by marriage or other relationship). The purpose of the family is to maintain the well-being of its ...

Apodidae The swifts are a family, Apodidae, of highly aerial birds. They are superficially similar to swallows, but are not closely related to any passerine species. Swifts are placed in the order Apodiformes with hummingbirds. The treeswifts are closely r ...

. It is

endemic Endemism is the state of a species being found in a single defined geographic location, such as an island, state, nation, country or other defined zone; organisms that are indigenous to a place are not endemic to it if they are also found elsew ...

to the

Philippines The Philippines (; fil, Pilipinas, links=no), officially the Republic of the Philippines ( fil, Republika ng Pilipinas, links=no), * bik, Republika kan Filipinas * ceb, Republika sa Pilipinas * cbk, República de Filipinas * hil, Republ ...

. Its natural

habitat In ecology, the term habitat summarises the array of resources, physical and biotic factors that are present in an area, such as to support the survival and reproduction of a particular species. A species habitat can be seen as the physical ...

is subtropical or tropical moist lowland

forest A forest is an area of land dominated by trees. Hundreds of definitions of forest are used throughout the world, incorporating factors such as tree density, tree height, land use, legal standing, and ecological function. The United Nations' ...

s. It was previously considered a subspecies of the

glossy swiftlet The glossy swiftlet (''Collocalia esculenta'') is a species of swift in the family Apodidae. It is found on the Indonesian island of Sulawesi and eastwards to New Guinea, the Bismarck Archipelago and the Solomon Islands. Taxonomy The glossy swi ...

Taxonomy

The ridgetop swiftlet was described by the American ornithologist

Harry Oberholser Harry Church Oberholser (June 25, 1870 – December 25, 1963) was an American ornithologist. Biography Harry Oberholser was born to Jacob and Lavera S. Oberholser on June 25, 1870, in Brooklyn, New York. He attended Columbia University, but did n ...

in 1906 as a subspecies of the

cave swiftlet The cave swiftlet or linchi swiftlet (''Collocalia linchi'') is a species of swift in the family Apodidae. It is found on the Indonesia islands of Sumatra, Java and Bali. It is a woodland species and nests in caves. The Bornean swiftlet was con ...

with the

trinomial name In biology, trinomial nomenclature refers to names for taxa below the rank of species. These names have three parts. The usage is different in zoology and botany. In zoology In zoological nomenclature, a trinomen (), trinominal name, or ternary ...

''Collocalia linchi isonota''. The type locality is the province of

Benguet Benguet (), officially the Province of Benguet ('';'' ; pag, Luyag/Probinsia na Benguet; ilo, Probinsia ti Benguet; ), is a landlocked province of the Philippines located in the southern tip of the Cordillera Administrative Region in the islan ...

on the island of

Luzon Luzon (; ) is the largest and most populous island in the Philippines. Located in the northern portion of the Philippines archipelago, it is the economic and political center of the nation, being home to the country's capital city, Manila, as ...

in the Philippines. The

specific epithet In taxonomy, binomial nomenclature ("two-term naming system"), also called nomenclature ("two-name naming system") or binary nomenclature, is a formal system of naming species of living things by giving each a name composed of two parts, bot ...

''isonota'' is from the

Ancient Greek Ancient Greek includes the forms of the Greek language used in ancient Greece and the ancient world from around 1500 BC to 300 BC. It is often roughly divided into the following periods: Mycenaean Greek (), Dark Ages (), the Archaic peri ...

''isos'' meaning "equal" or "similar" and ''nōton'' meaning "back". The ridgetop swiftlet was formerly treated as a subspecies of the

but was promoted to species status based on the results of a detailed analysis of the swiftlets in the genus ''

Collocalia ''Collocalia'' is a genus of swifts, containing some of the smaller species termed "swiftlets". Formerly a catch-all genus for these, a number of its former members are now normally (though not by all authors) placed in ''Aerodramus''. The genus ...

'' published in 2017. There are two subspecies: * ''C. i. sumbawae'' Oberholser, 1906 – northern

, (northern Philippines) * ''C. i. bagobo'' Hachisuka, 1930 –

Mindanao Mindanao ( ) ( Jawi: مينداناو) is the second-largest island in the Philippines, after Luzon, and seventh-most populous island in the world. Located in the southern region of the archipelago, the island is part of an island group of ...

Mindoro Mindoro is the seventh largest and eighth-most populous island in the Philippines. With a total land area of 10,571 km2 ( 4,082 sq.mi ) and has a population of 1,408,454 as of 2020 census. It is located off the southwestern coast of Luz ...

, Sulu Archipelago (southern Philippines)

Description

The ridgetop swiftlet is in length with a square tail. The back and upper surface of the wings are a dark dull blue with a moderate green gloss. The is sometimes slightly paler due to the white margins of feathers forming the . The throat and upper breast are dark grey with fine white scalloping merging into larger greyish chevrons over the lower breast and flanks, becoming white over the belly. There is sometimes a tuft of small feathers on the , the rear facing toe. This species lacks the white spots on the inner webs of the tail feathers that are present in some ''Collocalia'' species.

References

ridgetop swiftlet The ridgetop swiftlet (''Collocalia isonota'') is a small bird in the swift family Apodidae. It is endemic to the Philippines. Its natural habitat is subtropical or tropical moist lowland forests. It was previously considered a subspecies of th ...

Endemic birds of the Philippines

Taxa named by Harry C. Oberholser {{Apodiformes-stub