The Ashy Storm-Petrel is a mid-sized, sooty brown storm-petrel with a forked tail. Compared to other, distinctly more numerous species breeding in the same region, on islands off California and northern Baja California, it is smaller than the Black Storm-Petrel (Oceanodroma melania) with shorter and more rounded wings, but is larger than the Least Storm-Petrel (Oceanodroma microsoma), which species is further distinguished by its wedge-shaped tail. Birds are present at their colonies virtually year-round, but outside the breeding season it seems to disperse slightly more widely. Given its small population, considered to number fewer than 10,000 individuals, and significant declines registered until the early 1990s at least, the Ashy Storm-Petrel is currently treated as Endangered by BirdLife International. Fortunately, most of the population breeds on islands that are protected and specially managed for the species.