This species was first described as a subspecies of Leach's storm petrel (Hydrobates leucorhoa),[2] by the United States marine ornithologist David Ainley.

[3] He distinguished it on grounds of physiology, morphology and voice, separating it from Townsend's storm petrel (Hydrobates socorroensis) which breeds on the same islands in the summer whereas Hydrobates cheimomnestes breeds in the winter.

The general colour is dark sooty-brown but from a distance this appears black; pre-moult adults may look more brownish when the plumage is worn.

It is only known to breed on three islets off the southern end of Guadalupe Island, Mexico.

It nests in crevices and burrows, and the total world population probably does not exceed a few thousand birds.