[2] The black-tailed trogon has three subspecies according to the International Ornithological Committee (IOC): the nominate T. m. melanurus, T. m. macroura, and T. m. eumorphus.

The male of the nominate subspecies has a yellow bill and a blackish face and throat with an orange-red ring around the eye.

The male T. m. eumorphus is similar to the nominate, but its wings are darker, the tail bluer, and the white breast band narrower.

The nominate T. m. melanurus is found from eastern Colombia through southern Venezuela and the Guianas and south in northeastern Brazil as far as Maranhão state.

T. m. eumorphus is found south of melanurus, from southern Colombia through eastern Ecuador and Peru into northern Bolivia and east into Amazonian Brazil.

When treated separately, T. m. occidentalis is found in the São Paulo region of southeastern Brazil, but that area does not appear on the range maps of black-tailed trogon.

[5] The black-tailed trogon's diet includes a wide variety of insects, and also fruits and occasionally small amphibians and reptiles.

[5] The black-tailed trogon's breeding season varies widely across its large range, from March in Panama to September and October in Peru.