During courtship, mates fight on the water, pairs bill and by fighting attract other pairs until the whole ceremony tapers off. They copulate on the water. Puffins nest in colonies and construct nests by burrowing into loose soil 2-4 feet deep at tops of cliffs or on islands. The males do most of the burrow digging, using their beaks and webbed feet. Males stay with the females through the breeding season, and the pairs often sit outside the burrow. Eggs are laid between June and July, and usually only one egg is laid per pair. Eggs are round, white, and often spotted with brown. Both parents incubate by tucking the egg under one wing and leaning their body against it. Incubation lasts around 42 days. The newly hatched are fed very small fish. About 40 days after the chicks have hatched, they are abandoned by the parents, who go to sea; the chicks fast for a week and then jump into the sea at dusk or night, diving for their own food until they can fly at about 49 days old.
Average time to hatching: 42 days.
Average eggs per season: 1.