Auks, puffins and murres | Alcidae

Alken | Álcidos

Compact, short-necked seabirds, dark above and white below, with small narrow wings used both for flying and for rowing underwater. That double duty is a compromise: wing loading is high, take-off is laboured and the flight is fast and whirring with continuous beats, while legs set far back leave them upright but awkward on land. They breed in colonies on cliff ledges, in burrows and in crevices, laying a single egg with no nest material — strongly pear-shaped in the species that use bare ledges. After breeding most species shed all their flight feathers at once and cannot fly for some weeks.