White-tailed Emerald
Microchera chionura
Small hummingbird with restricted range in Costa Rica and western Panama. Male is mostly glittering emerald with a bright white lower belly and outer tail feathers. Female similar, but white extends up to the throat. Both sexes have relatively short and very slightly decurved bill. Compare with Snowy-bellied Hummingbird, which has coppery shoulders and rump and lacks white in tail. Found in the foothills of the Pacific slope, from around 800–2,200m, where it occurs in forest, edges, and gardens.
识别特征
The white-tailed emerald is 7.5 to 8 cm (3.0 to 3.1 in) long. Males weigh about 3.3 g (0.12 oz) and females 3.1 g (0.11 oz). Both sexes have an almost straight black bill whose mandible has a pinkish base. The adult male has bronzy green upperparts that becomes dark copper-bronze on the uppertail coverts. Its central two pairs of tail feathers are copper-bronze and the other three pairs white with black tips. It has a glittering green throat and chest and white belly, vent, and undertail coverts. The adult female also has bronzy green upperparts. Its central two pairs of tail feathers are bronzy and the other three pairs white with a black band near the tip. Its underparts are dull white with bronzy green flanks. The immature male is similar to the adult but with duller underparts that have grayish buff fringes to the feathers. Immature females have grayer underparts than the adult.
分类信息
The white-tailed emerald was formerly placed with the coppery-headed emerald in the genus Elvira. A molecular phylogenetic study published in 2014 found that these two species were closely related to the snowcap in the then-monospecific genus Microchera. The International Ornithological Committee and the Clements taxonomy placed the three species together in Microchera which has priority. However, BirdLife International's Handbook of the Birds of the World retains them in Elvira.<p>The white-tailed emerald is monotypic.
- 学名
- Microchera chionura
- 命名信息
- (Gould, 1851)
- 目
- Apodiformes
- 科
- Trochilidae
- 属
- Microchera
分布与栖息地
The white-tailed emerald is found in the highlands of the Pacific slope from south-central Costa Rica to central Panama and also locally on the Caribbean slope in Panama. It inhabits the edges and interior of moist to humid montane forest and secondary forest, and also plantations and gardens. In the forest interior males are often found in the canopy and females in the understory. In elevation it ranges from 750 to 2,000 m (2,500 to 6,600 ft) but in Costa Rica breeds mostly between 1,000 and 1,700 m (3,300 and 5,600 ft).
- 迁徙
- Resident species
行为
The white-tailed emerald's movements are not fully understood. In Costa Rica some individuals move both upslope and down outside the breeding season.<p>The white-tailed emerald feeds on nectar from a variety of flowering plants at both the edges and interior of the forest. In addition to nectar, it captures small arthropods by hawking from a perch.<p>The white-tailed emerald's breeding season extends from June to November. Males court females at leks in small groups. Nothing else is known about the species' breeding phenology and its nest has not been described.<p>The white-tailed emerald's song is "a prolonged, thin scratchy twittering mixed with buzzing or gurgling notes". It also makes "soft scratchy chipping notes" when foraging and "high-pitched, buzzy notes" when chasing.
保护状况
- 种群趋势
- declining
照片
分布
鸟叫声
其他鸟类
Bare-throated Bellbird
Procnias nudicollis
Males are unmistakable snow-white cotingas with a greeny-blue bare face and throat. Females are olive-green above with a streaked belly and gray-brown head. The song is a metallic, explosive and massively loud “boink” delivered from high perches in the canopy of humid forests.
Red-crested Bustard
Lophotis ruficrista
A medium-sized, black-bellied bustard with diagnostic white chevrons on a brown-and-black mottled back. The male has a brown-gray neck and slaty cap, and the female is plainer. The name is misleading, as the red crest is almost always hidden. It walks slowly and steadily in arid woodlands, where it is common but due to its camouflage often avoids detection. The song is a sequence of clicking “tic-tic” notes that are followed by a mournful piping “sweee-swee-sweee sweet” series that accelerates to a crescendo. The male indulges in an absurd display in which he flies nearly vertically into the sky and then folds his wings and somersaults down as if shot, only to unbelievably land on his feet. In flight the Red-crested Bustard’s all-black underwings differentiate it from Black-bellied Bustard, which has white windows in the underwing.
White-hooded Babbler
Gampsorhynchus rufulus
The large head, long tail, and hooked bill make this babbler resemble a shrike that had its head dipped into white paint. Only the adult has the full white head; younger birds have an orange crown and a white throat. Forages in lowland and foothill forests, usually in dense stands of bamboo. Travels in large, loud flocks, often with Rufous-headed Parrotbills and scimitar-babblers.
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