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White-tailed Emerald | Microchera chionura
Witstaartsmaragdkolibrie | Esmeralda coliblanca
The White-tailed Emerald is a small, green hummingbird of the Pacific slope of southern Costa Rica and western Panama. Both sexes show much white in the tail. It lives in the foothills and lower montane forest and feeds mainly in the understorey and at forest edges.
Voice
A thin, high tsit and a soft, dry chipping.
Recording: Frank T Spooner — CC BY-NC-SA 4.0 · converted to mono · xeno-canto
Identification
8 cm, with a short, straight black bill. The male is glossy green, with a white lower belly and undertail coverts and a white tail with a black subterminal band and green central feathers. The female is green above and white below, with grey-green spots on the flanks and the same white and black tail.
Confusion species
Coppery-headed Emerald Microchera cupreiceps lives only further north in Costa Rica and has a coppery crown and rump. Female Snowcaps Microchera albocoronata live on the Caribbean side and lower down. Garden Emerald Chlorostilbon assimilis has a dark, forked tail without white; the male is also entirely green below.
Habitat
Understorey and edges of humid foothill and montane forest, old secondary forest, shade coffee and scrub near forest, at about 750 to 2000 m, most often between 900 and 1600 m. It feeds low to mid-level at small flowers of shrubs and herbs and catches small insects.
Where the bird is most at home, classified by the vegetation units of Mexico and Central America.
Range and movements
Endemic to the guide area. In Costa Rica on the Pacific slope of the Cordillera de Talamanca, from the valley of the río General south to Coto Brus; in western Panama on the Pacific slope of Chiriquí and Veraguas.
- Resident
- dark = core range, pale = thinly spread
How and when to look
In southern Costa Rica around San Vito, for example in the gardens of the Las Cruces biological station, and in Panama around Boquete and Volcán, at flowering shrubs along forest edges and trails.
Conservation status
Not threatened. Locally fairly common within its small range. Forest clearance on the Pacific slope affects the species, but it also uses edges and secondary forest.
Scientific name
Microchera chionura | (Gould, 1851)
Gould described the species in 1851 as Trochilus (Thaumatias?) chionura; because it was later moved to another genus, the author and year stand in brackets. The genus Microchera was introduced in 1858 by Gould. Microchera is Greek, from mikros 'small' and khēra 'widow' (i.e. in mourning, black), after the tiny, very dark male. chionura is Greek, from khiōn 'snow' and oura 'tail', after the white outer tail feathers. The specimen the first description was based on came from David, Chiriquí, Panama, 600–900 m.