The Christmas Island swiftlet (''Collocalia natalis''), also known as the Christmas glossy swiftlet or the Christmas cave swiftlet, 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 ...

Christmas Island Christmas Island, officially the Territory of Christmas Island, is an Australian external territory comprising the island of the same name. It is located in the Indian Ocean, around south of Java and Sumatra and around north-west of the ...

, an Australian territory in the eastern

Indian Ocean The Indian Ocean is the third-largest of the world's five oceanic divisions, covering or ~19.8% of the water on Earth's surface. It is bounded by Asia to the north, Africa to the west and Australia to the east. To the south it is bounded by th ...

. It was formerly commonly treated as a

subspecies In biological classification, subspecies is a rank below species, used for populations that live in different areas and vary in size, shape, or other physical characteristics (morphology), but that can successfully interbreed. Not all species ...

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 Christmas Island swiftlet was described by the English naturalist

Joseph Lister Joseph Lister, 1st Baron Lister, (5 April 182710 February 1912) was a British surgeon, medical scientist, experimental pathologist and a pioneer of antiseptic surgery and preventative medicine. Joseph Lister revolutionised the craft of s ...

in 1889 with the scientific name ''Collocalia esculenta natalis''. It has usually been considered a

of the

(''Collocalia esculenta''). However, in 2008 the taxonomists

Les Christidis Leslie Christidis (born 30 May 1959), also simply known as Les Christidis, is an Australian ornithologist. His main research field is the evolution and systematics of birds. He has been director of Southern Cross University National Marine Scienc ...

and Walter Boles treated the swiftlet 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 ...

(''Collocalia linchi''). It was raised to species status based on 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.

Description

The Christmas Island swiftlet is a small swiftlet some in length. It is mainly glossy blue-black or green-black above, with dark grey underparts relieved by a prominent white belly and vent.Beeton p. 1

Distribution and habitat

This swiftlet is restricted to the 135 km² Christmas Island where it is commonly seen in large numbers in flight above the tropical

rainforest Rainforests are characterized by a closed and continuous tree canopy, moisture-dependent vegetation, the presence of epiphytes and lianas and the absence of wildfire. Rainforest can be classified as tropical rainforest or temperate rainfores ...

that covers 75% of the island, as well as over other terrestrial habitats there. It nests mainly in caves in the

limestone Limestone ( calcium carbonate ) is a type of carbonate sedimentary rock which is the main source of the material lime. It is composed mostly of the minerals calcite and aragonite, which are different crystal forms of . Limestone forms whe ...

cliffs surrounding the island.

Behaviour

Breeding

The swiftlet breeds deep in caves, in almost total darkness. It builds a small cup-shaped nest for its clutch of two eggs, high up on the cave wall and often sheltered by a

stalactite A stalactite (, ; from the Greek 'stalaktos' ('dripping') via ''stalassein'' ('to drip') is a mineral formation that hangs from the ceiling of caves, hot springs, or man-made structures such as bridges and mines. Any material that is soluble an ...

. The nests are made of dried

palm Palm most commonly refers to: * Palm of the hand, the central region of the front of the hand * Palm plants, of family Arecaceae **List of Arecaceae genera * Several other plants known as "palm" Palm or Palms may also refer to: Music * Palm (ba ...

fibres and lichen and are cemented to the cave wall with the bird's saliva.

Feeding

The swiftlet feeds aerially on flying ants and other insects.

Status and conservation

Garnett & Crowley (2000) considered the swiftlet, along with a suite of Christmas Island's other endemics, as critically endangered, with the principal threat coming from the

yellow crazy ant The yellow crazy ant (''Anoplolepis gracilipes''), also known as the long-legged ant or Maldive ant, is a species of ant, thought to be native to West Africa or Asia. They have been accidentally introduced to numerous places in the world's trop ...

s which were accidentally introduced to the island. The threat is not only that of direct ant predation of swiftlet nestlings, but also indirectly from potentially massive changes to the ecology of the island caused by the ants. Sometimes the bird breeds in hollow trees and these nests are susceptible to attack by the ants, but the ants do not enter the limestone caverns that are the principle breeding site and are not therefore likely to impact directly on the swiftlet. An application made in 2006 to list the swiftlet as threatened under the

Environment Protection and Biodiversity Conservation Act 1999 The ''Environment Protection and Biodiversity Conservation Act 1999'' (Cth) is an Act of the Parliament of Australia that provides a framework for protection of the Australian environment, including its biodiversity and its natural and cultu ...

was unsuccessful.Beeton, p.3.

Notes

References

* Beeton, Robert S. (Chair, TSSC). Advice to the Minister for the Environment and Heritage from the Threatened Species Scientific Committee (TSSC) on Amendments to the list of Threatened Species under the Environment Protection and Biodiversity Conservation Act 1999 (EPBC Act): ''Collocalia esculenta natalis'' (Glossy Swiftlet (Christmas Island)

* Christidis, Les; & Boles, Walter E. (2008). ''Systematics and taxonomy of Australian birds''. CSIRO Publishing: Melbourne. * Garnett, Stephen T.; & Crowley, Gabriel M. (2000). ''The Action Plan for Australian Birds 2000''. Environment Australia: Canberra.

* Higgins, P.J. (ed). (1999). ''Handbook of Australian, New Zealand and Antarctic Birds. Volume 4: Parrots to Dollarbird''. Oxford University Press: Melbourne. {{Taxonbar, from=Q5111433 Collocalia, Christmas swiftlet Birds of Christmas Island Christmas swiftlet