Christmas Island Swiftlet
Collocalia natalis
Generic-looking “white-bellied swiftlet”, but fortunately the only regular one on Christmas Island; migratory House and Pacific Swifts are larger, with bright white rump patches. Note the pale belly, dusky throat, weakly forked tail, and glossy dark upperparts, all traits typical of the genus Collocalia. Forages in swift, bat-like flight above a range of habitats on Christmas Island, sometimes forming loose flocks.
识别特征
The Christmas Island swiftlet is a small swiftlet some 9–11 cm (3.5–4.3 in) in length. It is mainly glossy blue-black or green-black above, with dark grey underparts relieved by a prominent white belly and vent.
分类信息
The Christmas Island swiftlet was described by the English naturalist Joseph Lister in 1889 with the scientific name Collocalia esculenta natalis. It has usually been considered a subspecies of the glossy swiftlet (Collocalia esculenta). However, in 2008 the taxonomists Les Christidis and Walter Boles treated the swiftlet as a subspecies of the cave swiftlet (Collocalia linchi). It was raised to species status based on a detailed analysis of the swiftlets in the genus Collocalia published in 2017.
- 学名
- Collocalia natalis
- 命名信息
- Lister, 1889
- 目
- Apodiformes
- 科
- Apodidae
- 属
- Collocalia
分布与栖息地
This swiftlet is restricted to the 135 km2 Christmas Island where it is commonly seen in large numbers in flight above the tropical rainforest that covers 75% of the island, as well as over other terrestrial habitats there. It nests mainly in caves in the limestone cliffs surrounding the island.
行为
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. The nests are made of dried palm fibres and lichen and are cemented to the cave wall with the bird's saliva.<p>The swiftlet feeds aerially on flying ants and other insects.
保护状况
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 ants 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 was unsuccessful.
照片
其他鸟类
Eurasian Magpie
Pica pica
Common and conspicuous, this flashy, long-tailed crow relative is unmistakable, and its loud chattering calls are a familiar sound in many areas. Found in open and semiopen areas from farmland and open woodland to towns and gardens, singly or more often in pairs or groups. Bulky stick nest often conspicuous in tall tree or hedgerow. Boldly pied plumage is distinctive, with white belly, white back, and white wing patches. Wings show blue-green gloss in good light.
Ankober Serin
Crithagra ankoberensis
A small seedeater of the Ethiopian highlands. The back and tail are brown and the head and underparts are heavily streaked. Note the faint narrow pale eyebrow stripe and the white spot below the eye. Found very locally in steep and rocky montane areas with grassland or heath, usually in small groups. Similar to Streaky Seedeater, but much smaller, slimmer, and smaller-billed, with a less strongly marked head. The calls are quiet twitters and rattles.
Red-chinned Lorikeet
Vini rubrigularis
An entirely green lorikeet with a small red patch on the chin, bordered with yellow. In flight, shows a green underwing with a yellow horizontal streak. Generally occurs in montane forest above 500 meters of elevation, most common above 1000 meters of elevation. Usually seen in flight. Similar Red-flanked Lorikeet differs in diagnostic bright red underwing with male having more red in the chin and a blue cheek, and female having a dark-streaked yellow cheek. Red-chinned is bigger and longer-tailed than pygmy- or hanging-parrots. Call is a high-pitched “pseet.”
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