Black guillemot

Black guillemot
Name	Black guillemot
Status	LC
Status system	IUCN3.1
Genus	Cepphus
Species	grylle
Authority	(Linnaeus, 1758)

Black guillemot

The Black guillemot is a medium-sized seabird of the family Alcidae, associated with rocky coasts and cold seas around the North Atlantic and Arctic regions. It is frequently observed near Iceland, Greenland, Norway, Scotland, and Alaska and is notable for its seasonal plumage changes and cavity-nesting habits. Ornithologists from institutions like the Royal Society for the Protection of Birds, American Ornithological Society, and BirdLife International study its population trends, migration patterns, and responses to climate-driven shifts in North Atlantic Oscillation and Arctic Council-era environmental change.

Taxonomy and systematics

The species was described by Carl Linnaeus in 1758 and placed in the genus Cepphus alongside the pigeon guillemot and spectacled guillemot; taxonomic treatments reference comparative morphology from collections at the Natural History Museum, London, the Smithsonian Institution, and the Swedish Museum of Natural History. Molecular phylogenetics using mitochondrial DNA markers has been conducted by researchers affiliated with University of Oxford, University of Copenhagen, and the Norwegian Institute for Nature Research, yielding insights into divergence times corresponding to Pleistocene glaciation events and faunal exchanges discussed during symposiums at The Royal Society and International Ornithological Congress meetings. Subspecies delineation—often recognizing forms such as C. g. grylle and C. g. mandtii—appears in checklists maintained by the International Union for Conservation of Nature, the American Ornithological Society Checklist Committee, and regional atlases produced by the British Trust for Ornithology.

Description

Adults in breeding plumage exhibit black plumage with a bold white wing patch and bright red feet; field guides produced by the Cornell Lab of Ornithology, Royal Society for the Protection of Birds, and National Audubon Society provide comparative plates alongside the common murre, Atlantic puffin, and razorbill. Juveniles and non-breeding adults show mottled gray and white plumage used in identification keys published by the British Ornithologists' Union, European Bird Census Council, and the Icelandic Institute of Natural History. Measurements—wing length, bill length, and mass—are standardized in manuals from the Handbook of the Birds of the World project and morphometrics datasets curated by the Global Biodiversity Information Facility and the eBird platform run by the Cornell Lab of Ornithology.

Distribution and habitat

The species occupies littoral zones across the North Atlantic Ocean basin, with breeding concentrations recorded in colonies near Svalbard, the Faroe Islands, Newfoundland and Labrador, and the Kamchatka Peninsula; seabird atlases from Canada's Fisheries and Oceans Canada and Norway's Directorate for Nature Management map seasonal ranges. Preferred habitats include rocky shores, sea cliffs, and offshore skerries documented in habitat surveys by the Scottish Natural Heritage, Greenland Institute of Natural Resources, and the Alaska Department of Fish and Game, with foraging ranges influenced by oceanographic features such as the Gulf Stream, Labrador Current, and upwelling zones monitored by the National Oceanic and Atmospheric Administration and the European Space Agency.

Behavior and ecology

Black guillemots forage by diving for benthic and pelagic prey such as small fishes and crustaceans; diet studies have been published by teams from the University of Tromsø, Memorial University of Newfoundland, and the Institute of Marine Research (Norway), often linking prey availability to regimes like the North Atlantic Oscillation and fisheries managed by Northwest Atlantic Fisheries Organization. Social behavior during the non-breeding season includes flocking documented in surveys by the Royal Society for the Protection of Birds and winter counts organized by the Audubon Society, while predator-prey interactions involve species such as the Arctic fox, Great black-backed gull, and marine mammals observed by researchers from the Svalbard Scientific Centre and the Norwegian Polar Institute.

Breeding and life cycle

Colonial and solitary nesting in rock crevices, under boulders, and in man-made structures is described in breeding accounts from the British Trust for Ornithology, Icelandic Institute of Natural History, and fieldwork by teams from the University of Glasgow and University of Alaska Fairbanks. Clutch size, incubation periods, and chick development are detailed in longitudinal studies supported by the Natural Environment Research Council and the National Science Foundation, with banding programs coordinated through the European Bird Ringing Centre and the North American Bird Banding Program tracking survival, natal philopatry, and dispersal. Timing of breeding aligns with regional phenology influenced by sea-ice retreat reported in assessments by the Intergovernmental Panel on Climate Change and marine monitoring by the North Pacific Marine Science Organization.

Conservation status

The IUCN lists the species as Least Concern, but regional populations face threats from oil pollution, bycatch, invasive predators, and climate-driven habitat shifts highlighted in reports by BirdLife International, WWF, and national agencies including Environment and Climate Change Canada and Norwegian Directorate for Nature Management. Conservation actions promoted by organizations such as the RSPB, Audubon Society, and the BTO include monitoring, marine protected areas informed by research from the International Council for the Exploration of the Sea, and mitigation of bycatch via policy dialogues at Convention on Biological Diversity meetings and regional fisheries forums like the Northwest Atlantic Fisheries Organization.

Category:Cepphus Category:Birds of the North Atlantic