Common Loon

Size & Shape

Adults can range from 61–100 cm (24–40 inches) in length with a 122–152 cm (4–5-foot) wingspan. The weight can vary from 1.6 to 8 kg (3.6 to 17.6 lbs). On average a Common Loon is about 81 cm (32 inches) long, has a wingspan of 136 cm (54 inches), and weighs about 4.1 kg (9 lbs).

Color Pattern

Breeding adults have a black head, white underparts, and a checkered black-and-white mantle. Non-breeding plumage is brownish, with the chin and fore-neck white. The bill is black-blue and held horizontally. The bill colour and angle distinguish this species from the similar Yellow-billed Loon.

Behavior

The Common Loon, like all divers, is a specialist fish-eater, catching its prey underwater, diving as deep as 200 feet (60 m). Freshwater diets consist of pike, perch, sunfish, trout, and bass; salt-water diets consist of rock fish, flounder, sea trout, and herring.

The bird needs a long distance to gain momentum for take-off, and is ungainly on landing. Its clumsiness on land is due to the legs being positioned at the rear of the body: this is ideal for diving but not well-suited for walking. When the birds land on water, they skim along on their bellies to slow down, rather than on their feet, as these are set too far back. The loon swims gracefully on the surface, dives as well as any flying bird, and flies competently for hundreds of kilometers in migration. It flies with its neck outstretched, usually calling a particular tremolo that can be used to identify a flying loon. Its call has been alternately called “haunting,” “beautiful,” “thrilling,” “mystical” and “enchanting.”

Common Loon nests are usually placed on islands, where ground-based predators cannot normally access them. However, eggs and nestlings have been taken by gulls, corvids, raccoons, skunks, minks, foxes, snapping turtles and large fish. Adults are not regularly preyed upon, but have been taken by sea otters (when wintering) and bald eagles. Ospreys have been observed harassing divers, more likely out of kleptoparasitism than predation. When approached by a predator of either its nest or itself, divers sometimes attack the predator by rushing at it and attempting to impale it through the abdomen or the back of the head or neck.

Habitat

Common Loons are migratory birds which breed in forested lakes and large ponds in northern North America and parts of Greenland and Iceland. They winter all along North America’s Pacific and Atlantic coasts as well as in Europe and Iceland.

Cool Facts

• 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.
• Migrating Common Loons occasionally land on wet highways or parking lots, mistaking them for rivers and lakes. They become stranded without a considerable amount of open water for a long takeoff. A loon may also get stranded on a pond that is too small.
• 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.
• The Common Loon is flightless for a few weeks after molting all of its wing feathers at the same time in midwinter.