A seabird breeding around St Paul Island in the southern Indian Ocean and on Gough Island in the South Atlantic. It eats small crustaceans at sea and ranges widely outside the breeding season.
It is blue-gray above and white below, with a dark M-shaped band across the back, a black tip to the upper tail, and blue-gray bill and feet. Its intermediate bill width helps distinguish it from related prions.
At breeding colonies it nests in burrows or caves, and pairs share incubation and chick-rearing. At sea it mainly eats small pelagic crustaceans. Tracking of 15 birds found foraging within 400 km of colonies during breeding and as far as about 7,550 km away during the non-breeding period, when they stayed at sea for around six months.
An extinction-risk assessment has not been added yet.