Black Guillemot

Identification

The black guillemot is a medium-sized seabird, 30 to 32 centimetres in length with a wingspan of 52 to 58 centimetres. In summer breeding plumage, adults are strikingly black overall with a distinctive large white patch on the upper side of their wings. The bill is black, long and slender, while the legs, feet and inside of the mouth are bright coral-red. Both sexes appear identical in the field. In winter, the bird undergoes a dramatic transformation: the upper plumage becomes barred with light grey and white, the head turns pale grey, and the underparts become white, though the white wing patch, black bill and red mouth lining are retained. Juveniles and immatures are easily identified by their white wing patch spotted with grey or brown feathers, a feature visible even at considerable distances.

Range & Habitat

The black guillemot is a circumpolar species distributed across boreal, low arctic and high arctic regions of the North Atlantic and Arctic Oceans, breeding between 43° and 82°N. Five recognized subspecies inhabit different parts of this range. In North America, they are found from the Gulf of Maine and New England northward across the northern coast as far as Alaska. In Europe and Asia, their range extends from the British Isles northward across the northern coasts of Asia. They are a fairly common breeding bird around the coasts of Ireland and western and northern Scotland, with smaller populations elsewhere in Britain. Approximately 40% of the global population breeds in high arctic waters, 30% in low arctic regions, and 30% in boreal waters.

Black guillemots are typically restricted to rocky shores, utilizing cliffs, crevices and boulders for nesting. They hunt the inshore waters, remaining resident in more temperate zones year-round, though large populations from high arctic regions migrate southward in winter when ice forces them to seek more open waters.

Behaviour & Diet

Black guillemots are social but unobtrusive birds, seen in single pairs or small groups around their breeding habitat. They breed in solitary pairs or small groups, with the breeding season running from late February to early May. Pairs nest above the high tide mark, typically in cliff crevices or gaps in boulders, though many pairs lay eggs directly on the ground without constructing true nests. Breeding pairs typically lay two-egg clutches and raise two chicks to fledging. The eggs are dull white to pale green, boldly marked with dark spots and blotches. Both parents incubate the eggs for 28 to 32 days. Chicks, covered in black down at hatching, remain under parental care for 30 to 40 days before fledging. Remarkably, once fledged, chicks are totally independent and do not accompany their parents. Young birds typically return to their natal colony to breed at three or four years of age.

The birds feed mainly by diving towards the sea floor in pursuit of fish, crustaceans and other benthic invertebrates. During the breeding season, they produce a distinctive high whistle call, and the bright red interior of their mouth (gape) is prominently displayed at this time.

Best Time & Places to See It

The breeding season from late February through early May is the best time to observe black guillemots, when they are most active and vocal around their nesting colonies. For European travellers, the coasts of Ireland, western and northern Scotland, and Iceland offer the most reliable viewing opportunities, with smaller populations in the Faroe Islands and Baltic region. North American visitors should focus on the Gulf of Maine and New England coastlines. High arctic regions, particularly around Greenland, Svalbard and northern Siberia, hold the largest breeding populations but are less accessible. The birds remain resident in temperate waters throughout the year, though numbers in high arctic regions diminish in winter as populations migrate south.

Photography Tips

Photographers should visit during the breeding season to capture the bird's striking black and white summer plumage with its brilliant coral-red feet and bill. The contrast between the glossy black body and the large white wing patches provides excellent photographic opportunities. Look for birds around rocky shores, cliffs and islands where they nest in small, accessible groups. The bright red gape and mouth lining are particularly prominent during breeding season and worth capturing in close-up shots. Early morning light on rocky coastlines will best showcase the bird's coloration. In winter, the pale grey and white plumage offers a different photographic opportunity, though less visually dramatic. Patience is essential, as these birds are not particularly mobile on land and often remain near their nesting sites, offering chances for steady, detailed photography.