A small storm petrel with dark plumage and a white rump, it breeds off western Mexico in summer and spends the nonbreeding season over the eastern Pacific.
Its plumage is dark, with a white rump crossed by a black line and a forked tail.
It breeds on islets off Guadalupe Island, Mexico. Nests are in coastal rock crevices or shallow burrows, and adults visit them at night. It eats small fish and crustaceans.
An extinction-risk assessment has not been added yet.