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.
Identification
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.
Taxonomy
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.
- Scientific name
- Microchera chionura
- Authority
- (Gould, 1851)
- Order
- Apodiformes
- Family
- Trochilidae
- Genus
- Microchera
Range and habitat
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).
- Migration
- Resident species
Behavior
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.
Conservation
- Population trend
- declining
Photos
Distribution
Bird Calls
Other Birds
Northern Chestnut-breasted Wren
Cyphorhinus dichrous
Found at higher elevations than other members of its genus. Shy and uncommon denizen of forest undergrowth from 1,100–2,000 m. Chunky and short-tailed, dark brown above with rich rufous neck and breast. Blue eyering. Sexes alike. Could recall an antbird, but especially note pointier bill with a thicker base. Typically found in pairs or small family groups foraging on or near the ground. More easily heard than seen: listen for repeated sets of 2–3 eerie whistled notes stepping up in pitch, with little to no break between each set.
Lineated Woodpecker
Dryocopus lineatus
Large ‘woody woodpecker’ of tropical forest in lowlands and foothills. Also ranges into semi-open areas with tall trees, mangroves, and other lightly wooded habitats. The tufted red crest and black face distinguish it from adult Pale-billed Woodpecker, which often occurs in the same areas. Also note that the white ‘braces’ on the back of Lineated are widely spaced, unlike Pale-billed. Laughing call suggests a flicker, and very unlike calls of Pale-billed.
Slender Antbird
Rhopornis ardesiacus
Large, long-tailed antbird. Males are gray, paler below, with a black bib. Females have a chestnut cap and white throat. Occurs in the understory of hillside deciduous forests that are rich in bromeliads and lianas. Both sexes sing a series of “peer” notes.
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