Closely allied but without the crest on the nape and hind neck is the Pink-collared Bustard (Heterotetrax vigorsi), which may be taken as typical of a group of three species separated under this genus (Heterotetrax). They are a third or more smaller than the last mentioned, the so-called Pink-collared Bustard being but twenty inches long, and dull ashy, minutely mottled with dark brown and black above, with the chin and upper throat jet-black. The whole plumage in life is glossed with a delicate pink luster which, however, fades after death. It is found usually in pairs among the scant herbage of the dry plains, and like the last has the habit of squatting close to the ground, where it fancies it has not been observed. Not far separated from this is the African Black Bustard (Compsotis afra), so named from the prevailing deep black color of the plumage, and the White-quilled Bustard (C. leucoptera), which has a large patch of white on the wing-quills.