Grey-tailed Mountaingem

The grey-tailed mountaingem, known scientifically as Lampornis cinereicauda, is a hummingbird of striking poise, endemic to the misty highlands of Costa Rica. This diminutive avian jewel measures approximately 12 cm in length and tips the scales at a mere 6 grams. The species exhibits sexual dimorphism; males boast an emerald green crown set against dark bronzy green upperparts and a contrasting gray tail, while females are adorned with bright green upperparts and a similarly gray tail.

Identification Tips

To identify the grey-tailed mountaingem, look for its medium-length straight black bill and the distinctive white stripe behind the eye. Males have a white chin and throat, with bright green flanking their neck and upper breast, transitioning to dark gray on the lower breast and vent area. Females, on the other hand, display dark rufous on their throat and belly, with gray undertail coverts edged in white or buff.

Habitat

This species is a denizen of the oak forests within the Cordillera de Talamanca, favoring the interior and edges of these woodlands, as well as shrubby clearings and nearby gardens.

Distribution

The grey-tailed mountaingem graces the southern reaches of Costa Rica, from elevations of 1,500 meters up to the timberline, where the forest gives way to the sky.

Behaviour

Post-breeding, these birds descend to the lower elevations of their range. Males are known to be territorial, vigorously defending their floral domains against intruders, and their interactions with other hummingbirds are dictated by a clear pecking order based on size.

Song & calls

The vocal repertoire of the grey-tailed mountaingem includes high-pitched "ziit" or "ziip" calls, as well as a "sputtery, bubbly" song that adds a melodious layer to their cloud forest habitat.

Breeding

Breeding season for the grey-tailed mountaingem spans from October to April. While the specifics of their nesting habits remain somewhat enigmatic, it is believed that their nests are akin to those of their close relatives, crafted from fine fibers and adorned with moss and lichen.

Diet and Feeding

Nectar forms the cornerstone of their diet, with males favoring epiphytes in the forest's heart and females more commonly foraging in shrubby zones. They also supplement their diet with small arthropods gleaned from foliage.

Conservation status

The IUCN has classified the grey-tailed mountaingem as Least Concern, though it is not immune to the threats posed by human encroachment, such as deforestation for timber and agriculture. Despite its limited range, the species is considered fairly common within its preferred habitat.