The loons or divers (family Gaviidae) are a family of birds belonging to the monotypic order Gaviiformes. These large aquatic birds are restricted to the northern hemisphere, where they breed in high latitude boreal forest lakes and migrate to more open waters in coastal bays and large lakes and reservoirs across Europe and North America. Their dagger-like bill adapted to a fish-based diet, semi-submerged snake-like jizz and daunting territorial calls are singular features among this family.
The family comprises 5 species in 1 genus, Gavia. The genus can be divided in three groups: the basal, red-throated lineage (1 species), the black-throated lineage (2 species) and the black-headed lineage (2 species). While all of them breed in Arctic and Subarctic regions, species in the same lineage have little overlap. For instance, one of the black-throated species is absent and only recorded as a vagrant in the Holarctic and the other one in the Western Palearctic.
Nuuksio National Park, Finland, 12 May 2023
Red-throated loon
Gavia stellata
Breeds in small, fish-less lakes close to larger water bodies in high latitudes and winters in the sea south to Florida or Taiwan. It is the smallest member of the family. The species is a local summer resident near Helsinki, and I have seen it several times in Finnish and Norwegian Lapland.
Lammi Biological Station, Kanta-Häme, Finland, 4 Oct 2023
Arctic loon
Gavia arctica
Breeds in large, open lakes in high latitude forests across the Old World and winters in the coastline of north Europe, Adriatic and Black Sea and Far Eastern Asia. Also known as black-throated diver. The species occurs during migration and breeds locally near Helsinki, and I have seen it several times in Finnish and Norwegian Lapland.
Svartnes, Varanger Peninsula, Norway, 3 Jun 2023
Yellow-billed loon
Gavia adamsii
Restricted to the high Arctic of west Siberia and Canada and Alaska, it has the northernmost distribution range of all divers. Also known as white-billed diver, this is the largest member of its family and the only species with a light-colored bill. I have seen this species in Norwegian Lapland.
