Early in the season the birds reestablish their pair bond (they mate for life) by billing, singing, shuffling around each other and participating in “water games.”Pigeon Guillemot colonies range in size from a couple pairs to hundreds of birds.
Inside their burrows, guillemots lay one or two eggs, which they incubate for approximately 32 days. After the chicks hatch, both parents catch and carry small fish—mainly gunnels, sculpins, sandlance and herring—to the dark brown chicks. The chicks consume the entire fish with one gulp. As the youngsters grow their parents feed them larger fish until the young are ready to leave the burrow, after about 35 days.
Juvenile guillemots fledge (leave the burrows) all by themselves usually under cover of darkness. They flutter and tumble from their high burrows and scurry to the nearby sea. For the first two weeks the fledglings are flightless yet they can feed themselves by diving underwater for prey. Once they develop flight feathers, the young birds quickly depart the colony and seek out more distant feeding areas.