The Black-tailed Trainbearer is a hummingbird of the Andes from Colombia to Peru. Males have long tails and search for nectar.
The male is about 15–26 cm long including its tail, with a long black tail and slightly curved black bill. The female has a shorter tail and spotted chest.
It forages for nectar in the middle and upper levels. A male may make a rattling wing sound while diving in front of a female.
An extinction-risk assessment has not been added yet.