An alcid, also known as an auk, is a member of the Alcidae family of birds.

Auks are superficially similar to penguins, tending to have black-and-white color schemes, upright postures, and some of their general habits. Nevertheless, they are not closely related, and are believed to be an example of convergent evolution. All currently living auks are notable for their ability to "fly" under water as well as in the air. Although they are excellent swimmers and divers, their walking appears clumsy.

Although not to the extent of penguins, auks have largely sacrificed flight, and also mobility on land, in exchange for swimming ability; their wings are a compromise between the best possible design for diving and the bare minimum needed for flying.

Not to be confused with

• penguin

Species

• auklet
• great auk
• guillemot
• little auk
• murrelet
• puffin

See also

• avian
• bird
• alcid