any of six species of small diving birds belonging to the auk family, Alcidae (order Charadriiformes). Murrelets are about 20 cm (8 inches) long, thin billed and, in winter, plain plumaged. They are sometimes called sea sparrows, as are auklets. In some species the young go to sea when only two days old. Their webbed feet are nearly full sized at hatching.

Breeding in Alaska are the marbled murrelet (Brachyramphus marmoratus), seen as far south as California, and Kittlitz's murrelet, (B. brevirostris), which reaches Japan. Most southerly is Xantus's murrelet (Endomychura hypoleucus), which nests on the hot coast of Baja California and (like some gulls of the region) travels north in winter.