A small Arctic seabird with a black breast and white belly in breeding plumage, and a white throat in nonbreeding plumage. It dives for small crustaceans and other marine prey.
Adults in breeding plumage are black above and on the breast, with a white belly. In nonbreeding plumage the black breast is absent and a white throat patch appears.
It nests on Arctic cliffs and rocky slopes, and dives underwater for small crustaceans and other prey. After breeding, it moves south in flocks.
An extinction-risk assessment has not been added yet.