Common Loon

Overview

The Common Loon (Gavia immer) is an iconic waterbird of North American wilderness, celebrated for its eerie, yodeling vocalizations that echo across northern lakes. This powerful diving bird is superbly adapted for underwater pursuit of fish, with legs positioned far back on its body for efficient swimming but making it nearly helpless on land. During breeding season, adults display striking black heads with ruby-red eyes, bold checkerboard patterns on their backs, and distinctive white 'necklaces' on their throats. Common Loons are monogamous and highly territorial during the breeding season, defending their lake territories vigorously. They require clear, fish-rich waters and undisturbed shorelines for nesting. Their populations have faced challenges from habitat loss, water pollution, lead poisoning from ingested fishing tackle, and human disturbance, though they remain relatively stable across much of their range. These birds are excellent indicators of aquatic ecosystem health due to their position as top predators in freshwater food chains. They can dive to depths exceeding 60 meters and remain submerged for several minutes while hunting. In winter, they undergo a complete molt, transforming into drab gray-brown birds that are often found in coastal marine environments far from their breeding grounds.

How to identify

Adults in breeding plumage (spring-summer) have glossy black heads and necks, ruby-red eyes, a sharp pointed bill, and bold black-and-white checkered backs with white underparts and a distinctive white 'necklace' band. Non-breeding adults are gray-brown above with white underparts and a pale eye-ring. Common Loons measure 66-91 cm in length with a wingspan of 127-147 cm. Their calls are distinctive: a tremolo (laughing call), wail (haunting three-note call), and yodel (territorial call used by males). In flight, they appear hunchbacked with large feet extending beyond the tail.

Habitat

Breeds on clear, oligotrophic freshwater lakes in forested regions, preferring lakes larger than 25 hectares with sufficient fish populations and islands or protected shorelines for nesting. Winters primarily in coastal marine waters, bays, and large ice-free lakes.

Distribution

Breeds across Canada, Alaska, northern United States including New England, Great Lakes region, and northern Rocky Mountains. Winters along the Pacific coast from Alaska to Mexico, Atlantic coast from Newfoundland to Florida, and Gulf of Mexico coast. Some populations are year-round residents in ice-free portions of breeding range.

Diet

Primarily piscivorous, feeding mainly on fish 10-25 cm in length including yellow perch, sunfish, trout, bass, and minnows. Also consumes crustaceans (crayfish), aquatic insects, leeches, and occasionally aquatic vegetation. Forages by diving and pursuing prey underwater using feet for propulsion.

Behavior

Highly territorial during breeding season. Exceptional divers capable of reaching depths over 60 meters and remaining submerged for up to 5 minutes. Nearly flightless on land due to rear-positioned legs; requires long takeoff runs (30+ meters) across water surface. Performs elaborate courtship displays including synchronized swimming and 'penguin dances.' Nocturnal migrants during spring and fall movements.

Reproduction & life cycle

Monogamous pairs return to same breeding territories annually. Nests built at water's edge or on small islands, typically containing 1-2 olive-brown eggs with dark spotting. Both parents incubate for 26-31 days. Chicks are precocial, able to swim within days but often ride on parents' backs for warmth and protection. Chicks fledge at 10-12 weeks but may remain with parents through migration. Sexual maturity reached at 2-3 years, though first breeding often delayed until 4-6 years.

When to look

Best observed April through October on breeding lakes; visible year-round along coastal wintering areas. Peak calling and breeding activity May-July. Migration occurs April-May (spring) and September-November (fall).

Cultural significance

The Common Loon holds deep cultural significance as a symbol of wilderness in North America and appears on the Canadian one-dollar coin ('loonie'). Indigenous peoples have incorporated loon imagery and calls into traditional stories, viewing the bird as a messenger between worlds. The loon's haunting call is emblematic of northern wilderness in literature and film. It is the state bird of Minnesota. Environmental groups use the loon as an indicator species for water quality monitoring and acid rain research.

Similar species

• Yellow-billed Loon (Gavia adamsii)
• Red-throated Loon (Gavia stellata)
• Pacific Loon (Gavia pacifica)

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