23-3-2017 SAN GERARDO DE DOTA COSTA RICA - GREEN THORNTAIL (MALE) (Discosura conversii)

The green thorntail (Discosura conversii) is a small hummingbird in the "coquettes", tribe Lesbiini of subfamily Lesbiinae. It is found in Colombia, Costa Rica, Ecuador, and Panama.

The green thorntail is found on the Caribbean slope in Costa Rica and the Pacific slopes of Panama, Colombia, and Ecuador almost to the Peruvian border. It is thought to also occur on the Caribbean side of eastern Panama. It is primarily a forest canopy species, inhabiting the upper levels of the interior and edges of humid montane forest and lowland evergreen forest. It also occurs at flowering trees in clearings. In elevation it mostly ranges from 700 to 1,400 m (2,300 to 4,600 ft) in Costa Rica, 600 to 1,200 m (2,000 to 3,900 ft) in Panama, from near sea level to 1,000 m (3,300 ft) in Colombia, and at 300 to 1,000 m (980 to 3,300 ft) in Ecuador.

The green thorntail is generally resident throughout its range but it also tends to move to its lower elevations during the wet season.

The green thorntail forages for nectar mostly at the tops of flowering trees but also from epiphytes and shrubs. It appears to favor legumes. It nectars while hovering with its tail cocked at nearly a right angle to its body. Its diet also includes small arthropods such as flies, wasps, and spiders that it captures by hawking from a perch and gleans from the underside of leaves while hovering.

Breeding male green thorntails perch on high bare twigs and sometimes give a dive display. The species' breeding season appears to vary across its range but are not well defined. It is thought to span from November to April in Costa Rica, and displays have been noted in Colombia in June. All hummingbirds lay two white eggs that are incubated by the female alone, but no details of the species' breeding phenology are known and the nest has not been described.

Tiny hummingbird with short straight bill. Male all shimmering green with distinctive, long, pointed tail feathers. Female has short tail and a distinctive white mustache. Both sexes show white band across rump. Most similar to coquettes but without orangey tones. Found in forested habitats and gardens; visits feeders.

This species has a very large range, and hence does not approach the thresholds for Vulnerable under the range size criterion (Extent of Occurrence <20,000 km2 combined with a declining or fluctuating range size, habitat extent/quality, or population size and a small number of locations or severe fragmentation). Despite the fact that the population trend appears to be decreasing, the decline is not believed to be sufficiently rapid to approach the threshold for Vulnerable under the population trend criterion (>30% decline over ten years of three generations). The population size has not been quantified, but it is not believed to approach the thresholds for Vulnerable under the population size criterion (<10,000 mature individuals with a continuing decline estimated to be >10% in ten years or three generations, or with a specified population structure). For these reasons the species is evaluated as Least Concern.