The Family alcidae is a family of birds with 23 species in total some of which are extinct e.g. the great auk, a rather large bird of the auk species that could not fly. The family alcidae includes species like the guillemots, auks, puffins and murrelets. Like the terns, the Auks belong to the order Charadriiformes and the lari suborder. Some of the genera that form the alcidae family include the Uria AlcaBrachyramphus Cerorhinca and Ptychoramphus genera

Most of the alcidae family species live in large colonies but in different environments that they have perfectly adapted to. While some of them (the guillemots) live on the coast nesting on rocky beaches, the puffins are comfortable and well adapted to a much cooler environment, preferring to nest in burrow on the edges of a cliff. Most of the alcidae species of birds weigh between 3 oz and 10oz and can mature to measure between 6 inches and 18 inches in length.

The auks are rather clumsy walkers, thanks to their small feet and relatively smaller wings. You will rarely find auks of puffins in flight due to the fact that they have smaller wings and have to flap their wings harder to gain height. They will fly only when they have to e.g. when escaping from a predator. Living in large colonies and cool environments gives predators a hard time. Their lack wings to fly high or feet to run fast have been well compensated by their prowess in water. They are good swimmers and divers, and have webbed feet to show for it.

This being a large family, not all the species are poor in flight and neither are they all good swimmers. The guillemots and the murrelets are better in water than the puffins and auks, which are in turn better in flight and in walking than the guillemots and the murrelets. Their respective diets are reflective of their environments and their adaptation. The good swimmers hunt in water for fish while the good in flight and walking tend to hunt off shore most of the time, but are not restricted to off shore hunting. In general, the species of the alcidae family are good divers and can dive to depths of 50 meters on average.

The alcidae family species have small and compact beaks that stand out from the rest of the body due to their colorful nature. They have short tails, short necks and short feet with strong claws, efficient for fishing and eating. Auks live in cool environments, which enable them to catch fish faster. Pursuit diving, the primary way through which auks hunt for their food has restricted them to the cooler waters of the northern hemisphere. Fish are known to move faster and are stringer in warm waters of the southern hemisphere and this is bound to give auks a harder time catching them. The disappearance of the fish habitats and the increasing competition between the auks and the cormorants has greatly reduced their numbers in the past century alone which s primarily due to global warming and pollution.