Racket-tailed Roller
Coracias spatulatus
Scarce and beautiful long-tailed roller. Varies geographically: birds in the southern part of the range have a blue breast, while those in the north have a pink breast. Distinctive tail shape: rounded rackets at the tips of the elongated outer tail feathers. Found in lush woodland, mostly miombo. Calls are an unmusical variety of hollow notes, squawks, and squeaks. Pink-breasted birds are very similar to Lilac-breasted Roller, but Racket-tailed has rufous on the shoulder and a distinctive tail shape.
识别特征
The racket-tailed roller is so named for the conspicuous elongated outer feathers on its tail which have long streamers ending in paddle-shaped tips. The bird is 28 to 30 cm (11 to 12 in) long with the streamers extending another 8 cm (3 in). The forehead and superciliary streak are white, the crown dull green, the back rufous and the tail blue. The underparts are pale blue with whitish streaking. In flight, the purple upper wing with its azure-blue stripe can be seen. The under wing is pale blue with a purplish-black trailing edge and tip. The bird somewhat resembles the European roller (Coracias garrulus) and the lilac-breasted roller (Coracias caudatus), but those species lack the distinctive tail streamers. The beak is black, the eye brownish and the legs are dull yellowish. The juvenile is similar to the adult but less vivid, and lacks the attenuated tail feathers. The voice is a harsh guttural shriek, uttered as it swoops down.
分类信息
The racket-tailed roller was formally described in 1880 by the naturalist Roland Trimen under its current binomial name Coracias spatulatus from a specimen collected near the Zambezi River in southern Africa. The specific epithet spatulatus is Modern Latin meaning "spatulate" or "spoon-shaped". The species is monotypic: no subspecies are recognised. A molecular phylogenetic study published in 2018 found that the racket-tailed roller was most closely related to the purple roller (Coracias naevius).<p>The phylogenetic relationships among the Coracias species are shown below, from the molecular study by Johansson et al. (2018)<p>Alternate names for the racket-tailed roller include the Angola racket-tailed roller and Weigall's roller.
- 学名
- Coracias spatulatus
- 命名信息
- Trimen, 1880
- 目
- Coraciiformes
- 科
- Coraciidae
- 属
- Coracias
分布与栖息地
- 迁徙
- Resident species
行为
Similar to other members of Coracias, this species hunts for prey from a perch in the mid-storey region of woodland. When it spots something edible on the forest floor it swoops down to grab the prey. The diet consists mainly of grasshoppers, beetles, insect larvae, scorpions and small lizards. This roller is usually a solitary bird or occurs in pairs, but may form small groups of six or seven birds. It is a territorial species, driving away intruders by rocketing from a height with a raucous screech, rolling from side to side as it levels off, before using its momentum to rise to a perch. It nests in a cavity in a tree trunk or branch about 7 m (23 ft) off the ground, often using a disused nest of a woodpecker or barbet. The clutch is laid in the unlined cavity and usually consists of three or four eggs, but little is known of the nesting habits of this species.
保护状况
- 种群趋势
- declining
照片
分布
鸟叫声
其他鸟类
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Melanospiza bicolor
Small sparrowlike bird found in the Caribbean and northern South America. Males are dull olive above with a variable amount of black on the face and breast. Females are plain grayish-olive overall; note the small size, short tail, and pinkish bill and legs. Very similar to female Sooty Grassquit. Found in pairs or small groups in shrubby or grassy areas and forest edge, typically on or near the ground.
Gray-headed Robin
Heteromyias cinereifrons
Large, plump robin of montane rainforest. Both sexes olive brown above, with gray crown and breast, stark white throat, and white wing patch, prominent in flight. Upright stance, large size, intricate plumage, and pale pink legs distinctive. Usually feeds on or near the ground in rainforest of far northern Queensland.
Pallid Dove
Leptotila pallida
A rather plain medium-sized dove, mostly restricted to western Ecuador but also occurs in western Colombia and extreme northwestern Peru. Within range, the main confusion species is White-tipped Dove. Pallid Dove has notably darker and warmer brown upperparts that contrast more with the whitish underparts. Like other members of the genus, Pallid is typically found on the ground (or flushing up into the understory). It is most often seen walking on roads or trails, or flying across quickly. There are a few places where it visits feeders. Within its limited range, it is fairly common, but be careful to separate from the equally (or more) common White-tipped Dove. Listen for its low-pitched, single “hoo” call.
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