Species Profile

Common Loon

Gavia immer

Common Loon

Quick Facts

Conservation

LCLeast Concern

Lifespan

20–30 years^[4]

Length

66–91 cm

Weight

2500–6100 g

Wingspan

122–152 cm

Migration

Long-distance Migrant

Listen for the haunting, yodel-like call echoing across northern lakes - it's the unmistakable sound of a loon on the water.

Also known as: Great Northern Diver

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Gallery

Appearance

The Common Loon is a large waterbird with a distinctive breeding plumage of black and white. Its head and neck are black with a greenish sheen, contrasting sharply with its white-checkered back and white underparts. The bird has a thick, dagger-like bill and red eyes.

In winter, adults moult into a more muted grey plumage with a white throat and underparts. Their bill also fades from black in the summer to pale grey in the winter.

Both sexes are similar in appearance, with females generally smaller. Juveniles resemble winter adults but with scaly-looking feathers on their backs.

Adult Common Loons are most similar to the Yellow-billed Loon (G. adamsii) in breeding plumage, although that species has a pale (not black) bill. Non-breeding adults also resemble smaller species like the Pacific Loon, Arctic Loon, and Red-throated Loon.

Identification & Characteristics

Colors

Primary: Black
Secondary: Grey
Beak: Black
Legs: Black

Attributes

Agility85/100

Strength75/100

Adaptability70/100

Aggression65/100

Endurance90/100

Understanding Attributes

Rated 0–100 based on research and observation. A score of 50 is average across all bird species. These attributes are relative and don't necessarily indicate superiority.

Habitat & Distribution

Common Loons breed on clear, freshwater lakes across northern North America, from Alaska to Greenland and south to parts of the northern United States. They prefer lakes with abundant fish populations and islands or secluded shorelines for nesting.

During winter, they migrate to coastal marine environments along North America's Atlantic and Pacific coasts, ranging from Alaska to Mexico and Newfoundland to Florida. Some populations also winter on large inland lakes that remain ice-free.

They are winter visitors to the United Kingdom coastline. Although rare inland, birdwatchers might spot them in shallow coastal areas between October and April, particularly in the southwest of England and along Scotland’s northwest coast.

Distribution

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Where to See This Bird

Explore regional guides for locations where this bird has been recorded.

Rutland

ResidentJan, Feb, Mar, Apr, May, Aug, Nov, Dec

Cornwall

ResidentJan, Feb, Mar, Apr, May, Jun, Oct, Nov, Dec

Dorset

ResidentJan, Feb, Mar, Apr, May, Nov, Dec

North Yorkshire

ResidentJan, Feb, Mar, Apr, May, Oct, Nov, Dec

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Diet

Common Loons are primarily piscivores, feeding on a variety of fish species, including perch, suckers, and minnows. They also consume aquatic invertebrates, amphibians, and occasionally aquatic plants.

Loons hunt by diving and pursuing prey underwater, using their sharp bill to catch and hold slippery fish.

Behaviour

Common Loons are exceptional divers, capable of staying underwater for up to five minutes while hunting fish. They are awkward on land due to the rear placement of their legs, which is an adaptation for swimming.

During the breeding season, loons are known for their elaborate courtship displays and territorial behaviours, including synchronised swimming and haunting vocalisations.

Calls & Sounds

The Common Loon's vocalisations are among the most distinctive of any North American bird. Their repertoire includes a haunting wail that rises and falls, often described as 'loon-like.'

They also produce a yodelling call used in territorial defence and a tremolo, a wavering call often given in flight or when alarmed.

The spooky but beautiful songs and calls of these birds have been featured in many television shows and films and will be familiar to many who have visited northern forested lakes in the spring and summer.

Nesting & Breeding

Common Loons form monogamous pairs and typically return to the same nesting site yearly. The breeding season begins in late spring, with courtship displays including synchronised swimming and vocalisations.

Nests are built close to the water's edge, often on small islands or hummocks. The nest is a mound of vegetation with a depression in the centre. Females usually lay two olive-brown eggs with dark spots.

Both parents incubate the eggs for about 28-30 days. The chicks are precocial and can swim within hours of hatching, but they often ride on their parents' backs for protection. Fledging occurs after 10-11 weeks.

Conservation

While currently listed as Least Concern globally, Common Loons face threats from habitat loss, water pollution, and climate change.

Conservation efforts focus on protecting nesting sites, managing water levels, and reducing mercury contamination in their aquatic habitats. In some regions, artificial nesting platforms have been introduced to support breeding populations.

LCLeast Concern

^[1]

Population

Estimated: 612,000 - 640,000 mature individuals^[3]

Trend: Stable^[2]

Elevation

Sea level to 500 meters

Additional Details

Predators:: Adult Common Loons have few natural predators, but their eggs and chicks are vulnerable to raccoons, gulls, ravens, and large fish. Bald Eagles occasionally prey on both chicks and adults.

Birdwatching Tips

Look for Common Loons on large, clear lakes in northern regions during summer.
Listen for their distinctive wailing and yodelling calls, especially at dusk and dawn.
In winter, search for them along coastal areas in their more subdued grey plumage.
Observe their diving behaviour; they often surface far from where they submerged.
Use a spotting scope for better views, as loons often stay far from shore.

Did You Know?

Common Loons have solid bones, unlike most birds with hollow bones, which helps them dive deep underwater.
They can swallow fish underwater and have been known to dive as deep as 60 meters (200 feet).
The Common Loon is the provincial bird of Ontario, Canada, featured on the Canadian one-dollar coin, known as the 'loonie.'
These large, powerful birds will use their sharp bills to protect their young from predators, and one adult was even suspected of killing a Bald Eagle in this way!