The Green Thorntail (Discosura conversii) is a small hummingbird that is a resident breeder from Costa Rica to westernEcuador. It occurs at middle elevations from 700-1400 m but may descend lower early in the wet season. In Costa Rica and Panama it is confined to the Caribbean slopes.
This is a forest canopy species. The nest is undescribed, but a published image  shows a female constructing a nest on a thin branch, so it is presumably similar to other cup nests built by species such as the Green-breasted Mango. All hummingbirds lay two white eggs incubated by the female alone.
Green Thorntail has mainly green upperparts, a white rump band and a blackish lower rump and tail. It weighs just 3 g. The 10 cm long male has the long wire-like tail that gives this species its name and green underparts. The 7.5 cm long female lacks the long tail and has blackish underparts with a green breast band. She has conspicuous white moustaches
The Green Thorntail is usually silent, but may give a quiet chip. These birds visit small flowers including those ofepiphytes and shrubs, and also take tiny flies and wasps. Breeding males perch on open branches and may give a dive display.
Conservation status:Least concern
(Bourcier & Mulsant, 1846)
BirdLife International (2004). Discosura conversii. 2006 IUCN Red List of Threatened Species. IUCN 2006. Retrieved on 11 May 2006. Database entry includes justification for why this species is of least concern
Stiles and Skutch, A guide to the birds of Costa Rica ISBN 0-0814-9600-4