The ridgetop swiftlet (Collocalia isonota) is a small bird in the swift family Apodidae. It is endemic to the Philippines.

Ridgetop swiftlet
Ridgetop swiftlet nesting in Bukidnon, Mindanao, Philippines
Scientific classification Edit this classification
Domain: Eukaryota
Kingdom: Animalia
Phylum: Chordata
Class: Aves
Clade: Strisores
Order: Apodiformes
Family: Apodidae
Genus: Collocalia
Species:
C. isonota
Binomial name
Collocalia isonota
Synonyms
  • Collocalia esculenta isonata
  • Collocalia linchi isonota

Its natural habitat is subtropical or tropical moist lowland forests. It was previously considered a subspecies of the glossy swiftlet.

Description

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The ridgetop swiftlet is 9–10 cm (3.5–3.9 in) in length with a square tail.[1] The back and upper surface of the wings are a dark dull blue with a moderate green gloss. The rump is sometimes slightly paler due to the white margins of feathers forming the uppertail coverts. 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 hallux, 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.[2]

Taxonomy

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The ridgetop swiftlet was described by the American ornithologist Harry Oberholser in 1906 as a subspecies of the cave swiftlet with the trinomial name Collocalia linchi isonota. The type locality is the province of Benguet on the island of Luzon in the Philippines.[3][4] The specific epithet isonota is from the Ancient Greek isos meaning "equal" or "similar" and nōton meaning "back".[5] The ridgetop swiftlet was formerly treated as a subspecies of the glossy swiftlet but was promoted to species status based on the results of a detailed analysis of the swiftlets in the genus Collocalia published in 2017.[2][6]

There are two subspecies:[6]

Ecology and behavior

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Not much is known about this species' diet but it is presumed to feed on small insects in flight.

Nests on man made structures, caves, and cliffs. Their nest is made out of moss, dry grass, and occasionally feathers, all of which are bonded with its saliva. Not much else is known about its breeding.

Habitat and conservation

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Seen in almost any habitat including coastal areas, montane forest , agricultural lands and even roads. It is still most frequently seen in forests and clearings.

International Union for Conservation of Nature does not yet recognize this as its own species. It has assessed its parent species, the glossy swiftlet as least-concern species.[7]

References

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  1. ^ Chantler, P.; Boesman, P. (2017). del Hoyo, J.; Elliott, A.; Sargatal, J.; Christie, D.A.; de Juana, E. (eds.). "Glossy Swiftlet (Collocalia esculenta)". Handbook of the Birds of the World Alive. Lynx Edicions. Retrieved 23 August 2017.
  2. ^ a b Rheindt, Frank E.; Christidis, Les; Norman, Janette A.; Eaton, James A.; Sadanandan, Keren R.; Schodde, Richard (2017). "Speciation in Indo-Pacific swiftlets (Aves: Apodidae): integrating molecular and phenotypic data for a new provisional taxonomy of the Collocalia esculenta complex". Zootaxa. 4250 (5): 401–433. doi:10.11646/zootaxa.4250.5.1.
  3. ^ Oberholser, Harry C. (1906). "A monograph on the genus Collocalia". Proceedings of the Academy of Natural Sciences of Philadelphia. 58: 177–212 [182 in key, 208].
  4. ^ Peters, James Lee, ed. (1940). Check-list of Birds of the World. Vol. 4. Cambridge, Massachusetts: Harvard University Press. p. 230.
  5. ^ Jobling, James A. (2010). The Helm Dictionary of Scientific Bird Names. London: Christopher Helm. p. 208. ISBN 978-1-4081-2501-4.
  6. ^ a b Gill, Frank; Donsker, David, eds. (2017). "Owlet-nightjars, treeswifts & swifts". World Bird List Version 7.3. International Ornithologists' Union. Retrieved 2 August 2017.
  7. ^ Kirwan, Guy M. (2022). "Ridgetop Swiftlet (Collocalia isonota), version 2.0". Birds of the World. doi:10.2173/bow.ridswi1.02species_shared.bow.project_name. ISSN 2771-3105.