Dusky crag martin 
(Nhạn nâu hung, Ptyonoprogne concolor)

The dusky crag martin (Ptyonoprogne concolor) is a small passerine bird in the swallow family Hirundinidae.

Hirundinidae: Latin hirundo swallow.
The genus name Ptyonoprogne is derived from the Greek ptuon (πτύον), "a fan", referring to the shape of the opened tail, and Procne (Πρόκνη), a mythological girl who was turned into a swallow.
The specific concolor is from Latin, con "together", and color "colour" and refers to the bird's uniform colouration.