Common Loons are large, diving waterbirds with rounded heads and dagger-like bills. They have long bodies and short tails that are usually not visible. In flight, they look stretched out, with a long, flat body and long neck and bill. Their feet stick out beyond the tail (unlike ducks and cormorants), looking like wedges. They measure 66 to 91 centimeters in length, with a wingspan of 104 to 131 centimeters. In summer, adults have a black head and bill, a black-and-white spotted back, and a white breast. From September to March, adults are plain gray on the back and head with a white throat. The bill also fades to gray. Juveniles look similar, but with more pronounced scalloping on the back. Common Loons are stealthy divers, submerging without a splash to catch fish. Pairs and groups often call to each other at night. In flight, notice their shallow wingbeats and unwavering, bee-lined flight path. Common Loons breed on quiet, remote freshwater lakes of the northern U.S. and Canada, and they are sensitive to human disturbance. In winter and during migration, look for them on lakes, rivers, estuaries, and coastlines. This species is of low conservation concern.
The Common Loon swims underwater to catch fish, propelling itself with its feet. It swallows most of its prey underwater. The loon has sharp, rearward-pointing projections on the roof of its mouth and tongue that help it keep a firm hold on slippery fish.
Loons are water birds, only going ashore to mate and incubate eggs. Their legs are placed far back on their bodies, allowing efficient swimming but only awkward movement on land.
Migrating loons have been clocked flying at speeds more than 70 mph.
Biologists estimate that loon parents and their 2 chicks can eat about a half-ton of fish over a 15-week period.
Source: Common Loon Overview and Identification Information, All About Birds, The Cornell Lab of Ornithology