Common Loon

The common loon (Gavia immer) is a large diving bird found on lakes and slow rivers in Banff National Park. Its haunting, tremolo call is one of the signature sounds of the Canadian wilderness and a familiar backdrop on backcountry lakes in the Lake Louise area.

Identification

About the size of a large duck, with a heavy, dagger-like bill. Breeding adults have a black head, black-and-white checked back, and a distinctive necklace of white stripes. Non-breeding and juvenile birds are dull grey-brown above with a white throat and belly. Loons sit low in the water and dive rather than dabble. In flight, they appear hunchbacked with rapid wingbeats and need a long water runway to take off.

Habitat and diet

Loons breed on clear, fish-bearing lakes with little human disturbance. They feed mostly on small fish, diving to depths of 30 metres or more, and will also take aquatic insects and crustaceans. Nesting occurs on shorelines and small islands; chicks ride on a parent’s back for the first few weeks.

Behaviour

Territorial during breeding season. Their calls carry long distances across water: the wail, the tremolo, the yodel, and the hoot each serve a different purpose, from contact calls to alarm. Loons are sensitive to boat traffic and shoreline disturbance near nest sites.

Viewing

Occasionally seen on Lake Louise and more often on quieter backcountry lakes. Early morning and evening are the best times to hear them. Keep your distance from birds on the water and avoid approaching shoreline nests. Canoeists and kayakers should give loons wide berth, especially when chicks are present.