The Atlantic Puffin is sometimes known as the "sea parrot" because of its distinctive bill: in the breeding season the bill becomes vividly coloured with red, blue-grey and ivory. The colours become paler when the nesting season ends.

The nest is actually a burrow dug into soft, turfy, coastal slopes for a distance of about 90 cm (3 ft.). The female lays one egg.

Atlantic Puffins live in colonies. In Canada, the largest are found on islands off Newfoundland, where estimates of single-colony populations have reached 250 000. Winters are spent offshore. This species is Newfoundland and Labrador's emblematic bird.

The Atlantic Puffin is an expert swimmer. It is also an adept hunter, often emerging from an underwater foray with six or more small fish dangling from its bill.

Atlantic Puffins are generally 26 to 29 cm (10 to 11 in.) long. Their wingspan is 47 to 63 cm (1.5 to 2 ft.).