Giant Cowbird
Molothrus oryzivorus
Rather large blackbird of tropical lowlands; male is much larger than female. Found in forest edges, pastures, orchards, and open grassy areas along rivers; often in small groups. In breeding season, hangs around oropendola colonies, where it lays its eggs in oropendola nests and relies on them to raise its offspring. Thick neck accentuates small head with very stout, pointed bill. Flight is strong and fairly direct, with distinctive flap-flap-flap-glide progression. Eye color varies: red in Mexico and Central America, yellowish in parts of South America.
识别特征
The male giant cowbird is 34 cm (13 in) long, weighs 174–242 g (6.1–8.5 oz) and is iridescent black, with a long tail, long bill, small head, and a neck ruff which is expanded in display. The female is smaller, averaging 29 cm (11 in) in length and weighing 144–167 g (5.1–5.9 oz). The female is less iridescent than the male, and the absence of the neck ruff makes her look less small-headed. Juvenile males are similar to the adult male, but browner, and with a pale, not black, bill.<p>It is a quiet bird, particularly for an icterid, but the male has an unpleasant screeched whistle, shweeaa-tpic-tpic. The call is a sharp chek-chik. They are also very adept mimics.
分类信息
The giant cowbird was formally described in 1788 by the German naturalist Johann Friedrich Gmelin in his revised and expanded edition of Carl Linnaeus's Systema Naturae. He placed it with the orioles in the genus Oriolus and coined the binomial name Oriolus oryzivorus. Gmelin based his account on the "rice bird" from Cayenne that had been described in 1782 by the English ornithologist John Latham in his multi-volume work A General Synopsis of Birds. The specific epithet is from Latin oryza meaning "rice" and -vorus meaning "eating". The giant cowbird is now one of six cowbirds placed in the genus Molothrus that was introduced in 1832 by William Swainson.<p>Two subspecies are recognised:
- 学名
- Molothrus oryzivorus
- 命名信息
- (Gmelin, JF, 1788)
- 目
- Passeriformes
- 科
- Icteridae
- 属
- Molothrus
分布与栖息地
It is associated with open woodland and cultivation with large trees, but is also the only cowbird that is found in deep forest.
- 迁徙
- Resident species
行为
Like other cowbirds, it is a brood parasite, laying its eggs in the nests of oropendolas and caciques. The eggs are of two types, either whitish and unspotted, or pale blue or green with dark spots and blotches. The host's eggs and chicks are not destroyed. Their icterid hosts breed colonially, and defend their nests vigorously, so even a large, bold and aggressive species like the giant cowbird has to cover an extensive territory to find sufficient egg-laying opportunities. Several giant cowbird eggs may be laid in one host nest.<p>This gregarious bird feeds mainly on insects, and some seeds, including rice, and forages on the ground or in trees. It also searches for fruit, nectar, and arthropods along lakes and rivers, and in banana plantations and corn. It rarely perches on cattle, unlike some of its relatives, but in Brazil it will ride on capybaras as it removes ticks and/or horse flies.
保护状况
- 种群趋势
- declining
照片
分布
鸟叫声
其他鸟类
Apricot-breasted Sunbird
Cinnyris buettikoferi
Male is a distinctive, long-billed sunbird with iridescent purplish-blue throat, yellow breast and belly, and diagnostic bright orange patch on chest. Female is grayish-olive with a yellow eyebrow and dull yellow underparts. Singles or pairs can be found in lightly wooded areas, forest edge, and plantations within lowlands and low hills. Confined to the island of Sumba. Female has a thinner, longer bill than female Brown-throated Sunbird, and further differs in presence of yellow eyebrow. Gives a very high-pitched undulating, warbling song. Calls include “tzit” and “tew” notes and a repetitive “weet-weet-weet…”.
Blue Eared-Pheasant
Crossoptilon auritum
A large gray terrestrial bird with an elegantly frilly tail. Bright red face and upswept white facial plumes (“ears”) are unique in its range. Found in both subalpine and alpine areas, preferring open forests in the former and scrubby meadows in the latter. Forages in small groups for most of the year, pairing off during the breeding season. Hunted in much of its range, thus wary and found in remote areas, far from settlements.
Gray Warbler-Finch
Certhidea fusca
Small, slender-billed Galápagos finch. Best identified by its thin bill, brownish-gray plumage, and the island on which it is seen. Male sometimes has a faint, buffy wash on throat and face. Occurs only on Floreana, Española, Santa Fé, San Cristóbal, Genovesa, Marchena, Pinta, Wolf, and Darwin. Not found together with the very similar Green Warbler-Finch. Might be mistaken for a young female Yellow Warbler (some of which show only a trace of yellow), but note more finch-like bill and a shorter tail. Inhabits dry, coastal scrub and is often seen at the edge of beaches.
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