Auks are the sea birds which belong to family Alcidae. Auks have its 22 species, out of which 21 are living including the great, little auk or dovekie and the razorbill or razor-billed auk. They are similar to penguins. They look similar to penguins because of their black-white color and vertical standing. Auk's legs are positioned at the back of the body, which gives them the upright posture. Also some of their habits are similar to penguins.
But unlike penguins, modern Auks can fly except Great Auk. However, instead of penguins, they are more closely related to the gulls. Auk's size varies in length from 15 to 45 cm. However their weight ranges from 85 g to 1 kg. Due to short leg their walk seems awkward. They have waterproof feathers and are good divers and swimmers.
Auks mostly roam over the open sea and return to land only for breeding. However, some of its species like Common Guillemot spends much time protecting their nest from the harm. Auks found in large numbers in the Northern Hemisphere.
Due to their small wings their flight is not that graceful, but they can able to fly underwater to catch their prey. Most of the auks live on eating fish, but some species rely on plankton alone. Auks have misleading coloration, which helps them underwater as its front white color becomes completely invisible to the fish
All the species of Auk are live in flocks except the Brachyramphus murrelets. Some Auk species nest on cliff edges, while others nests on rocky coasts and in burrows. Many of its species have different name in different areas like the guillemots in Europe are known with the name murres in North America.
Auks are generally monogamous and mate for life. All the Auks lay 1 or 2 eggs in a burrow nest or on bare stone ledges. Only the marbled murrelet constructs a nest in the branches of seaside pines. It incubates the eggs for 29 to 42 days. The birds which nests in a colony, gives a egg uniquely patterned, which helps them to identify their own egg. Also the chicks are recognized by their unique voice.