Dollarbird
Eurystomus orientalis
Heavily built, flat-headed dark blue bird with a short bright red bill. In flight has a characteristic white circle, or ‘dollar’, on each underwing. Juvenile lacks red bill. May resemble mynas in flight, but note longer wings, larger head, and more powerful, less frantic flight. Nests in cavities; typically tree hollows. Frequently perches on power-lines or in the tops of tall dead trees.
识别特征
The oriental dollarbird has a length of up to 30 cm. It is dark brown but this is heavily washed with a bluish-green sheen on the back and wing coverts. Its belly and undertail coverts are light coloured, and it has glossy bright blue colouring on its throat and undertail. Its flight feathers are a darker blue. Its bill is short and wide and in mature animals is coloured orange-red with a black tip. It has very light blue patches on the outer parts of its wings which are highly visible in flight and for which it is named. The females are slightly duller than the males but overall the two are very similar. Immature birds are much duller than the adults and do not have the blue colouring on their throats. They also have brown bills and feet instead of the red of the adults.
分类信息
The Oriental dollarbird was formally described by the Swedish naturalist Carl Linnaeus in 1766 in the twelfth edition of his Systema Naturae under the binomial name Coracias orientalis. Linnaeus based his description on "Le Rollier des Indes" that had been described and illustrated by the French zoologist Mathurin Jacques Brisson in 1760. The type locality is the island of Java in Indonesia. The Oriental dollarbird is now placed in the genus Eurystomus that was introduced in 1816 by the French ornithologist Louis Pierre Vieillot.<p>A molecular phylogenetic study published in 2018 found that the azure dollarbird (Eurystomus azureus) was nested in a clade containing subspecies of the Oriental dollarbird. Formerly, some authorities have also considered the broad-billed roller and the azure dollarbird to have been subspecies of the oriental dollarbird. The generic name derives from Ancient Greek eurustomos 'wide-mouthed' and the specific epithet is Latin orientalis 'eastern'. Alternate names for the oriental dollarbird include the Asian dollarbird, dark roller, dollar roller, dollarbird, eastern broad-billed roller and oriental broad-billed roller.<p>Ten subspecies are recognized:
- 学名
- Eurystomus orientalis
- 命名信息
- (Linnaeus, 1766)
- 目
- Coraciiformes
- 科
- Coraciidae
- 属
- Eurystomus
分布与栖息地
The oriental dollarbird is found from Australia to Japan and India. It breeds in northern and eastern Australia between the months of September and April and winters in New Guinea and nearby islands. The birds prefer open wooded areas with hollow-bearing trees to build nests in.
- 迁徙
- Complete migrants
行为
The oriental dollarbird is most commonly seen singly with a distinctive upright silhouette on a bare branch high in a tree, from which it hawks for insects, returning to the same perch after a few seconds.
保护状况
- 种群趋势
- declining
照片
分布
鸟叫声
其他鸟类
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Large swallow; very local summer resident in mountains of northwest Mexico. Favors open pine-oak forest, usually with big dead pine snags and cliffs, where nests in cavities. Ranges widely in highlands and foothills, coming to drink at ponds and lakes. Usually seen as singles or small groups, which may associate with other swallows. Male blue-black overall with contrasting white belly. Female similar to several other martins, but clean white belly contrasts more strongly with dark breast.
Yellow Honeyeater
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A medium-sized honeyeater with a short black bill. Almost entirely plainish yellow and featureless, lacking stripes, bars, cheek patches, and wingbars, which help with identification. Listen for its piercing “whee-whee” or a single high-pitched whistle. Found pretty much anywhere with trees in far northern Queensland including gardens and mangroves, where it forages high up in the trees.
Gray Kingbird
Tyrannus dominicensis
A relatively pale kingbird, medium-gray above and white below with a darker face mask. Primarily a Caribbean species with limited range in U.S.; found around the edge of dense woodland, especially near the coast. Also seen in more suburban areas. Often perches conspicuously on a snag, treetop, or powerline. Feeds on insects. Listen for its high-pitched twittering calls. Compare with Eastern and Loggerhead Kingbirds; Gray Kingbird has lighter gray upperparts, a thicker bill, and lacks white tail tips.
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