Loons are captivating aquatic birds recognized for their distinctive appearance and haunting vocalizations. These birds possess streamlined bodies, powerful legs positioned far back on their frames, and remarkable diving capabilities, all adaptations that suit their life in water. Their physical design allows for efficient underwater propulsion, enabling them to pursue fish with agility. Loons spend most of their lives on water, only coming ashore for nesting.
The Loons of the World: A Species Count
There are five recognized species of loons, also known as divers in some parts of the world, found across the Northern Hemisphere. These species include the Common Loon, Yellow-billed Loon, Arctic Loon, Pacific Loon, and Red-throated Loon. Each species occupies distinct geographical ranges, often overlapping during migration periods.
- Common Loon: Breeds across Canada, northern United States, Greenland, Iceland, and parts of Eurasia; winters along US and European coasts.
- Yellow-billed Loon: Breeds in Arctic Alaska, northern Canada, and Eurasia; winters along northern Pacific and northwestern Norway.
- Arctic Loon: Widespread across northern Europe and Asia, with a smaller summer presence in western Alaska.
- Pacific Loon: Breeds in the North American Arctic and parts of Eurasia; winters along the Pacific coast.
- Red-throated Loon: Has the broadest global distribution, breeding across Arctic regions and wintering in northern coastal waters.
Distinguishing Features of Each Loon Species
Common Loon (Gavia immer)
The Common Loon (Gavia immer) is a large bird, measuring 66-91 cm in length with a wingspan of 127-147 cm. During breeding, it displays a striking black head and neck with an iridescent sheen, a black-and-white checkered back, and pure white underparts. Its eyes are deep red, and it has a thick, dagger-like black bill. In winter, its plumage shifts to a plainer gray above and white below. Common Loons are known for complex vocalizations: a distinctive wail, a laugh-like tremolo (when agitated), and a territorial yodel unique to each male. This species requires 30 to 600 feet of open water for liftoff.
Yellow-billed Loon (Gavia adamsii)
The Yellow-billed Loon (Gavia adamsii) is the largest loon, measuring 76-97 cm with a 135-160 cm wingspan. Its breeding plumage resembles the Common Loon’s, featuring a black head and white underparts. A distinguishing feature is its long, straw-yellow bill, often slightly upturned. Unlike the Common Loon’s checkered pattern, its back has large white spots. Its calls are an eerie wail, lower pitched than the Common Loon’s, with louder, harsher yodels. This species nests in tundra and winters in marine coastal environments.
Arctic Loon (Gavia arctica)
The Arctic Loon (Gavia arctica), also called the Black-throated Diver, is a medium-sized species, 40-81 cm long. Breeding adults have a black throat contrasting with a gray head and hindneck, plus white and black stripes on the neck sides. Their upperparts are black with white squares. A distinguishing feature from the similar Pacific Loon is a distinct white flank patch visible in all plumages. It produces low humming and moaning contact calls, and males perform a strong yodel heard over long distances. When diving, it extends its neck and executes a slight leap into the water.
Pacific Loon (Gavia pacifica)
The Pacific Loon (Gavia pacifica) is a medium-sized loon, 58-74 cm long. Its breeding plumage features a gray head, a black throat with subtle purple reflections, and a checkered black-and-white pattern on its back and mantle. It lacks the white flank patch seen on the Arctic Loon. Its bill is dagger-shaped and usually gray or whitish, held horizontally while on the water. Its vocalizations include an “ark”-like call during feeding and a loud, eerie wail or yodel during the breeding season. This species nests on tundra lakes and requires 30 to 50 yards of open water for flight.
Red-throated Loon (Gavia stellata)
The Red-throated Loon (Gavia stellata) is the smallest loon, measuring 53-69 cm in length. In breeding plumage, it has a light gray head and neck, a distinct dark red throat patch, and a dark gray-brown back. Its thin bill is often held slightly upturned. In winter, its plumage becomes paler, with a smooth gray back. Unlike other loons, both male and female produce calls, including simple wails, rolling growls, quacks, and high-pitched shrieks. This species is unique among loons for its ability to take flight directly from water or land without an extended running start. It often forages away from its breeding territory and does not carry its young on its back.