This small seabird breeds on islands near the southern tip of South America and in the southern Indian Ocean. Some reach New Zealand waters in winter.
The back and wings are blue-grey to blackish, the underside is white, and a dark M crosses the back from wingtip to wingtip.
It breeds colonially on islands in the Falklands, southern Chile, and the Kerguelen region; pairs share incubation and chick care.
It forms flocks at sea near breeding islands and visits colonies at night, using burrows or crevices by day.
Its M marking is less distinct than in other prions. It has a narrow bill and a pale line above and behind the eye.
An extinction-risk assessment has not been added yet.