Common Loon: where and when to see them

The common loon is a large northern waterbird with a powerful bill and a haunting voice associated with forest lakes. Breeding adults wear a black head, white necklace markings and a strikingly checked back. In winter they become much greyer and move to marine waters, where coastal observers may know them better than lake visitors do. Their legs sit far back on the body, making them effective swimmers but awkward walkers.

Size

66-91 cm long

Weight

2.5-6 kg

Lifespan

20-30 years

Status

Least Concern

Breeding pairs defend lake territories and communicate with several distinctive calls, including wails, tremolos and the male's yodel. Nests sit close to the water because movement on land is difficult. Small chicks sometimes ride on an adult's back, gaining warmth and protection. After breeding, loons move toward larger waters and coastal wintering areas. They can remain out of sight while pursuing prey, then surface far from their previous position. Loons are long-lived birds, sometimes reaching ages over 20 years in the wild, often returning to the same breeding territories annually. They are proficient swimmers and divers, using their powerful webbed feet for propulsion underwater, steering with their wings.

• Small chicks may ride on their parents' backs.
• Only males give the territorial yodel.
• The feet are positioned so far back that walking is difficult.
• Breeding black-and-white plumage is replaced by a much greyer winter appearance.

October to April is a useful broad window for New England coastal observation, when migrants and wintering birds occupy salt water. Late spring and summer are better for breeding plumage on northern inland lakes. Freeze-up, storms and migration timing cause substantial local variation. In New England, the peak of fall migration often occurs from late October through November, offering excellent opportunities to see many individuals. Conversely, spring migration back to breeding grounds typically happens from late March to May, with birds often in full breeding plumage.

Breeding habitat is mainly clear northern lakes with fish, sheltered nesting edges and sufficient open water for takeoff. Winter habitat includes coastal bays, sounds and nearshore marine waters. In New England, lakeside breeding observation usually requires an inland excursion. Breeding lakes must be large enough to support a long "runway" for takeoff and landing. Their heavy bones make loons less buoyant than other water birds, an adaptation for diving which also means they cannot take off directly from land.

Fish dominate the diet, supplemented by crustaceans and other aquatic animals. Prey is captured through active pursuit beneath the surface and usually swallowed before the bird resurfaces. Adults providing for chicks may bring small fish to the surface for transfer. Young chicks are often fed invertebrates during their first week, gradually switching to small fish. Loons typically hunt by sight, so clear water is essential for successful foraging.

Common name

Common Loon

Scientific name

Gavia immer

Animal group

Birds

Size

66-91 cm long

Weight

2.5-6 kg

Lifespan

20-30 years

Status

Least Concern

Identification

Its large, straight, daggerlike bill distinguishes it from the slimmer red-throated loon, which often holds its finer bill tilted upward. The common loon displays a distinctive black head and white-striped collar in breeding plumage, contrasting with its dark back and white belly. In winter, its plumage is duller, featuring a gray-brown back and a white chin and throat.