Black Guillemot Identification Guide

Key Field Marks

• Small, chunky auk with a slim black bill and, uniquely among auks, bright coral-red legs and feet visible at rest and in flight.
• Breeding adult is entirely sooty black except for a large, oval white patch on each upperwing.
• Non-breeding adult becomes largely pale grey and white, finely barred and mottled with dark feathering on the back, but retains the diagnostic white wing patch.
• Inside of the mouth is bright red, occasionally visible when the bird calls or gapes.
• Flight is fast and whirring on rounded wings, low over the water.

Separating It From Similar Species

• Pigeon Guillemot, its Pacific counterpart, looks very similar but shows a dark bar crossing the white wing patch and a different, non-overlapping range (Black Guillemot is Atlantic/Arctic only).
• Other small auks like Dovekie or auklets lack the large white wing patch and red legs entirely.
• Winter-plumage birds can look confusingly pale, but the retained clean white wing patch combined with red feet remains diagnostic year-round.

Where and When to See It

• Resident along rocky coasts of the North Atlantic and Arctic Ocean, including Scotland, Scandinavia, Iceland, Greenland, and northeastern North America.
• Prefers rocky shorelines, cliffs, and boulder fields for nesting, foraging in nearby shallow inshore waters rather than far offshore.
• Largely non-migratory, though northernmost populations may move short distances south or offshore in winter when ice covers coastal waters.

Voice and Behavior

• Vocalizations include a high, thin, wheezing whistle, often given in pairs or small groups near nest sites.
• Nests in rock crevices, boulder piles, or occasionally man-made structures along the shoreline, usually as scattered pairs rather than dense colonies.
• Dives from the surface to forage on small fish (notably blennies and sculpins) and invertebrates in shallow coastal waters, often close to shore.