After the breeding season, they lose some of their horny bill plates and molt as well. Reproduction 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.