Ducula is a genus of the pigeon family Columbidae, collectively known as imperial pigeons.
Imperial pigeons are found in forests of southern Asia, New Guinea, northern Australia and the Pacific islands. 

Columba: Latin columba (“dove, pigeon”). Ancient Greek κόλυμβος (kólumbos, “a diver”), from κολυμβάω (kolumbáō, “dive, plunge headlong, swim”).
The genus name Ducula is from the Latin dux genitive ducis meaning "leader".

1/ Mountain imperial pigeon (Gầm ghì lưng nâu, Ducula badia), also known as the maroon-backed imperial pigeon or Hodgson's imperial pigeon
2/ Green imperial pigeon (Gầm ghì lưng xanh, Ducula aenea)
3/ Pied imperial pigeon (Gầm ghì trắng, Ducula bicolor)