The Green-tailed Trainbearer is a high-Andean hummingbird. The male's long tail is distinctive, and the bird visits flowers in shrubland.
The male has a green body and a long green tail. The female has a shorter tail and pale, speckled underparts.
It lives in high-elevation shrubland and takes nectar from flowers. The cited Peru account records it on high Andean slopes.
The bill is black, relatively short, and nearly straight.
An extinction-risk assessment has not been added yet.