
Great Northern Loon
Gavia immer
The common loon or great northern diver is a large member of the loon, or diver, family of birds. Breeding adults have a plumage that includes a broad black head and neck with a greenish, purplish, or bluish sheen, blackish or blackish-grey upperparts, and pure white underparts except some black on the undertail coverts and vent.
Photo: Wikimedia Commons (CC) via https://en.wikipedia.org/wiki/Common_loon
Taxonomy & Classification
Kingdom
Animalia
Phylum
Chordata
Class
Aves
Order
Gaviiformes
Family
Gaviidae
Genus
Gavia
Great Northern Loon belongs to the family Gaviidae, order Gaviiformes, within the Aves class.
Species Profile
The common loon or great northern diver is a large member of the loon, or diver, family of birds. Breeding adults have a plumage that includes a broad black head and neck with a greenish, purplish, or bluish sheen, blackish or blackish-grey upperparts, and pure white underparts except some black on the undertail coverts and vent. Non-breeding adults are brownish with a dark neck and head marked with dark grey-brown. Their upperparts are dark brownish-grey with an unclear pattern of squares on the shoulders, and the underparts, lower face, chin, and throat are whitish. The sexes look alike, though males are significantly heavier than females. During the breeding season, loons live on lakes and other waterways in Canada, the northern United States, and southern parts of Greenland and...
Great Northern Loons face significant population declines primarily due to habitat loss from shoreline development and water level fluctuations that destroy nesting sites. Climate change is altering lake ecosystems and prey availability, while pollution from mercury, lead fishing tackle, and oil spills causes direct mortality and reproductive failure.
Key Facts
Habitat & Distribution
Common loons are mainly Nearctic, and breed from 48° N to the Arctic Circle, locally south to 40° N and north to 78° N. Deep lakes with warm surface waters, relatively low biological productivity and low turbidity where their fish prey are easy to see are habitats where breeding loons are more successful in raising young. For protection from predators, common loons favour lakes with islands and...
Threats
IUCN Red List: Endangered
Great Northern Loons face significant population declines primarily due to habitat loss from shoreline development and water level fluctuations that destroy nesting sites. Climate change is altering lake ecosystems and prey availability, while pollution from mercury, lead fishing tackle, and oil spills causes direct mortality and reproductive failure.
Mercury and lead poisoning
Shoreline development and human disturbance
Water level fluctuations from dam operations
Climate change impacts on lake ecosystems
Oil spills and marine pollution
National vs Global Threat Status
How this species is assessed at the national level compared to its IUCN global status (EN).
| Country | National Status | Global Status | Comparison |
|---|---|---|---|
| EU | LCLeast Concern | ENEndangered | Lower local risk |
| EU | LCLeast Concern | ENEndangered | Lower local risk |
National Red List data sourced from the National Red List Project (nationalredlist.org, ZSL) and country-specific Red List authorities.
Community Sightings
Report a sightingNo community sightings yet. Be the first to report!
Sources & Attribution
How to Cite
IUCN: IUCN (2025). The IUCN Red List of Threatened Species. Version 2025-1. Available at: https://www.iucnredlist.org. doi:10.2305/IUCN.UK.2025-1.RLTS
GBIF: GBIF.org (2025). GBIF Home Page. Available at: https://www.gbif.org
National Red Lists: ZSL (2025). National Red List. Zoological Society of London. Available at: https://www.nationalredlist.org
This page: SpeciesRadar (2025). Great Northern Loon (Gavia immer). SpeciesRadar: Intelligence for Earth's Biodiversity. Available at: https://speciesradar.org/species/great-northern-loon