Lesser Frigatebird
Fregata ariel
The smallest of the frigatebirds, but note that the female is larger than the male. Adults are easier to identify than younger birds. Adult males are almost entirely black with a red throat and white spurs emanating outwards from the body onto the wing. Adult females have a black belly and throat, a white breast and hind collar, with similar white spurs on their sides. Juvenile and immature plumages are variable and are best separated from other frigatebirds by size when comparison is possible. Mostly silent except while breeding in oceanic islands. Strongly pelagic during non-breeding season but wind-blown or fatigued birds can be found from continental coasts.
识别特征
The lesser frigatebird is the smallest species of frigatebird and measures 66–81 cm (26–32 in) in length with a wingspan of 155–193 cm (61–76 in) and long forked tails. Male birds weight 625–875 g (1.378–1.929 lb). Female birds are heavier and weight 760–955 grams (1.676–2.105 lb). Like all frigatebirds the male has a large red sac on the front of the throat which is inflated during courtship. Courtship display also involves a variety of calls, bill rattling and spreading of the wings. The male is mostly all black save for a white patch on the flank which extends on to the underwing as a spur. Males also have a pale bar on the upper wing. Females have a black head and neck with a white collar and breast as well as a spur extending on to the underwing. The female also has a narrow red ring around the eye. Juveniles and immature birds are more difficult to differentiate but the presence of the spurs of white in the armpits is a helpful distinguishing sign.<p>Frigate birds are built for flying; they rarely swim and cannot walk but can manage to climb around the trees and bushes in which they nest. They have a very light skeleton and long narrow wings and are masters of the air. Their name probably derives from the fact that they harass other sea birds such as boobies and tropicbirds as they return to their nests from feeding, forcing them to disgorge their catch, which is then swooped upon and caught by the frigate birds before it reaches the water below. This practice seems to be more common among female frigate birds, but probably only accounts for a fairly small proportion of the diet, which mainly consists of squid and flying fish scooped up from the surface of the sea.
分类信息
The lesser frigatebird was first described as Atagen ariel by the English zoologist George Gray in 1845 from a specimen collected on Raine Island, Queensland, Australia. The lesser frigatebird is one of five closely related species of the genus Fregata. The other four are: the great frigatebird (Fregata minor), the Christmas frigatebird (Frigata andrewsi), the magnificent frigatebird (Fregata magnificens) and the Ascension frigatebird (Fregata aquila). The genus is the only member of the family Fregatidae.<p>Three subspecies are recognised:<p>Some ornithologists have questioned the validity of these subspecies as they appeared to differ only in their size. Few museum specimens of the isolated Atlantic F. a. trinitatis exists, making comparisons difficult, but a comprehensive study published in 2017 found that it differed in both color of plumage and skeletal details, leading to the recommendation of treating it as a separate species (Fregata trinitatis).
- 学名
- Fregata ariel
- 命名信息
- (Gray, GR, 1845)
- 目
- Suliformes
- 科
- Fregatidae
- 属
- Fregata
分布与栖息地
The lesser frigatebird is said to be the most common and widespread frigatebird in Australian seas (Lindsey, 1986). It is common in tropical seas, breeding on remote islands, including Christmas Island in the Indian Ocean in recent years. These birds are most likely to be seen from the mainland prior to the onset of a tropical cyclone, and once this abates they disappear again.
- 繁殖区
- TrO : widespread, tropical Indian and Pacific ocean is., also nw South Atlantic
- 非繁殖区
- to waters off se Africa, sw India and Sri Lanka, throughout Indonesian Arch. and Philippines to Taiwan, New Guinea waters, n Australia and Melanesia
- 迁徙
- Resident species
保护状况
- 种群趋势
- declining
照片
分布
鸟叫声
其他鸟类
White-chinned Petrel
Procellaria aequinoctialis
Common, rather large dark petrel of the Southern Ocean; regular migrant north into Humboldt Current. Usually looks wholly blackish with a pale, ivory-colored bill—the white chin is often just a few feathers and frequently is difficult to see in the field, although it can be more extensive, especially on Atlantic and Indian Ocean birds. White-chinned is obviously larger than dark-billed Sooty Shearwater and much smaller than giant-petrels, which have huge pale bills. Pale bill tip distinguishes White-chinned from similar Westland and Parkinson’s Petrels, which have dark bill tip.
Yellow-browed Toucanet
Aulacorhynchus huallagae
Small, green toucan found only in remote regions along the east slope of the Andes in northern Peru. Most of its cloud forest habitat is currently inaccessible without a serious expedition, so few birders have ever encountered this rare species. Plumage is mostly green with a red rump and tail tip, a white throat, anda blue breast-band. Distinguished from Blue-banded Toucanet by the yellow (not white) streak above the eye and the vertical white stripe at the base of the bill. Mostly black bill and blue breast-band help separate it from Southern Emerald-Toucanet and Chestnut-tipped Toucanet.
Maroon Oriole
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Large, pale-eyed songbird of lower and middle elevations of montane forests. Male blood red with inky black head and wings and dark bill; female similar but less richly colored. Juvenile brown above, pale with dark stippling below, paler bill, and tawny undertail coverts. Birds in Taiwan and central Vietnam are much brighter red overall. Usually seen in pairs or small flocks, sometimes with mixed-species flocks. Pairs often engage in an ethereal duet: male gives a series of melodic notes, to which the female responds with a long, airy whistle. Also gives harsh, rasping calls.
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