Cepphus grylleblack guillemot

Geographic Range

The Black guillemot is a circumpolar species distributed in boreal, low arctic and high arctic regions of the North Atlantic and Arctic oceans. Black guillemots can be found in coastal areas from the Gulf of Maine, New England across parts of the northern coast of North America, as far as Alaska. In Europe and Asia they are found from the British Isles and northward across the northern coast of Asia. The largest concentrations can be found among islands of the high and low arctic. Wintering populations disperse as far south as Rhode Island in North America and France in the eastern Atlantic (Johnsgard 1987; Nettleship and Evans 1985; Nettleship 1996).


Generally Black guillemots are restricted to rocky shores due to their nesting requirements. They nest most often in crevices among stones and boulders at the base of cliffs or cracks in cliffs, and less often under rocks among vegetation and under driftwood. In the high arctic some cliff sites may be as high as 230m. Artificial cover (debris on shore, harbor walls, under buildings) has allowed guillemots to nest in areas where they may not have previously.

Foraging habitat varies dramatically with the seasons. During the breeding season birds forage in inshore waters generally less than 50m in depth. Although they remain fairly close to shore year round, in winter months black guillemots are more pelagic, frequently feeding along pack ice edges where pack ice occurs. Some overwinter in polynyas of the high north (Brown 1985; Cairns 1992; Harris and Birkhead 1985; Johnsgard 1987; Nettleship 1996; Winn 1950).

Physical Description

A relatively small seabird, Black guillemots are approximately 32cm in length. In breeding plumage, as their name implies, Black guillemots are black from bill to tail. They also have large white wing patches, and bright red feet, legs and inside the mouth. As many as seven sub-species have been described based on variations in size, bill and wing length, and plumage. After an early fall moult adults take on a patchy black and white plumage that has been described as "salt and pepper" and legs become a paler red. This winter plumage retains the white wing patch on the black wing, however the body plumage becomes white below and barred black and white above with a black bill and mostly white head. Newly fledged birds are similar to wintering adults and yearlings have an adult-like plumage with brownish spots in the white wing patch (Bedard 1985; Gaston 1985; Johnsgard 1987; Nettleship 1996; Stokes and Stokes 1996).

  • Range mass
    325 to 550 g
    11.45 to 19.38 oz


Black guillemots breed in relatively small scattered colonies and lay 2 eggs. The typical reproductive cycle is as follows. Some adults over-winter near breeding colonies while the others return between late February and early May. Birds have been seen searching for suitable nest sites (see habitat section for nesting requirements) immediately after copulation and eggs are usually laid between late May and mid June. Guillemots have a double brood patch; two eggs are the standard clutch size but sometimes one and more rarely three are laid. More experienced parents often lay slightly earlier and have a larger mean clutch size. Once the last egg is laid incubation is continuous with both parents sharing shifts for 28 to 32 days. Colony attendance is highest in the early morning. Down-covered semi-precocial chicks take 3 to 4 days to fully hatch then are left unattended in the nest. As the chicks get older they wander inside the nest crevice. Both sexes feed the demanding chicks up to 20 fish a day until they fledge at age 30 to 40 days. Sometimes parents must entice young from the nest with fish, but once fledged, chicks are on their own. The average breeding success ranges from 0.48 to 1.6 young per pair with losses due to predation, bad weather, and flooding from high tides. By age three or four, young birds start to breed and join this cycle (Harris and Birkhead 1985; Hilden 1994; Johnsgard 1987; Nettleship 1996; Winn 1950).

  • Average eggs per season
  • Average time to hatching
    25 days



Black guillemots form monogamous pairs and show remarkable site fidelity, returning to the same colonies and often the same nest site year after year. Their social behavior ranges anywhere from solitary pairs to highly colonial. In the southern portion of their range guillemots are less social and less colonial, living in colonies of 10's and 100's while birds of the high arctic occur in colonies as large as several thousand. In some areas nesting habitat will overlap with other Alcids (Razorbills, Alca torda and Atlantic puffins, Fratercula arctica) with one documented case of Razorbill and guillemot eggs in the same hole.

Black guillemots show a variety of social behaviors towards each other. They are territorial over nest sites, perching sites on stones and strongly defend perching sites above nests. Aggressive behaviors include the typical guillemot call (high-pitched, open mouth whistle), lunging attacks with open bills, aggressive walk stance (hunched posture and wings partially opened), and surface, aerial and underwater chases. "Leap frogging" chases have been described with individuals flying over others and landing in front of the other on the water. Around Grand Manan Island, Canada, groups of up to 40 or 50 individuals have been observed swimming in lines possibly as a group foraging technique since members of the line often continuously look underwater by dunking their heads followed by simultaneous dives (pers. obs.) Fairly elaborate courtship displays have been described involving head bowing, whistling, pairs turning and swimming in circles, and males stepping up and down with alternating feet while standing on females backs during copulation (Cairns 1980; Harris and Birkhead 1985; Johnsgard 1987; Nettleship 1996; Winn 1950).

Communication and Perception

Food Habits

Like other members of the Alcidae family, C. grylle are adapted to wing-propelled swimming allowing them to dive deeply where they feed mainly on fish on or near the seafloor. Prey items include sandlance (Ammodytidae), gunnels (Pholidae), sculpins (Cottidae), pricklebacks (Stichaeidae), Arctic cod (Boreogadus saida) and many other fish as well as many invertebrates: polychaetes, molluscs, jellyfish, crustaceans, sponges, crabs, and even barnacles. They are known to dive for nearly 2 minutes and up to estimated depths of 50m. Many patterns of foraging behavior have been found. There is typically a morning, and sometimes evening, peak in foraging activity, but in some areas feeding may be continuous throughout daylight hours. Foraging distribution has been shown to change with tidal cycles where birds prefer waters of moderate flow. Seasonal cycles also exist with guillemots feeding inshore during the breeding season and farther offshore or around pack ice edges during the winter (Bradstreet and Brown 1985; Cairns 1986; Cairns 1992; Johnsgard 1987; Nettleship 1996; Nol and Gaskin 1987; Winn 1950).

Economic Importance for Humans: Positive

During the 1800's and first half of the 20th century Black guillemots were taken for food; adults were hunted, young collected and eggs taken from nests. These activities were known to occur in parts of eastern Canada (mainly Labrador and the Gulf of St. Lawrence), Iceland, Faeroe Islands, British Isles, areas of the White Sea, and many Scandinavian countries. Many laws prevent such activities now (Nettleship and Evans 1985).

Conservation Status

Black guillemots have no threatened status and are quite abundant, especially in some regions of the high arctic. Total population of the North Atlantic and Arctic oceans was estimated in 1985 at 270,000 pairs (200,000-350,000). In some areas population declines have been observed. In the past local reductions may have resulted from hunting or egging. Currently some populations seem to be increasing and expanding their distributions. Locally introduced predators, oil spills, and commercial gill-net fishing may impact guillemots, however there are no serious threats globally. High rates of nest visits by scientists have also been shown to decrease nesting success (Brown and Nettleship 1984; Cairns 1980; Johnsgard 1987; Nettleship and Evans 1985; Nettleship 1996).

Other Comments

As was mentioned above, Black guillemots forage inshore during the breeding season and generally lay 2 eggs. This is typical of other guillemots (Pigeon guillemot, Cepphus columba and Spectacled guillemot, Cepphus carbo) but atypical of most members of the Alcidae family who forage far from shore and produce a single egg. Explanations for this distinctive strategy suggest that the inshore foraging and the double clutch go hand in hand. With Alcids it has been suggested that clutch size is a function of food availability or the ability of adults to provide food for young. Therefore guillemots have developed an inshore foraging strategy during the breeding season giving them easy access to food during chick rearing periods. This may allow them to raise more young than long-distance foraging Alcids. Studies of Black guillemot energy expenditure during chick rearing support this hypothesis (Birkhead and Harris 1985; Mehlum et al. 1993).


Robert Ronconi (author), University of Alberta, Cindy Paszkowski (editor), University of Alberta.


Arctic Ocean

the body of water between Europe, Asia, and North America which occurs mostly north of the Arctic circle.

Atlantic Ocean

the body of water between Africa, Europe, the southern ocean (above 60 degrees south latitude), and the western hemisphere. It is the second largest ocean in the world after the Pacific Ocean.

World Map


uses sound to communicate

bilateral symmetry

having body symmetry such that the animal can be divided in one plane into two mirror-image halves. Animals with bilateral symmetry have dorsal and ventral sides, as well as anterior and posterior ends. Synapomorphy of the Bilateria.


uses smells or other chemicals to communicate


the nearshore aquatic habitats near a coast, or shoreline.


animals that use metabolically generated heat to regulate body temperature independently of ambient temperature. Endothermy is a synapomorphy of the Mammalia, although it may have arisen in a (now extinct) synapsid ancestor; the fossil record does not distinguish these possibilities. Convergent in birds.


offspring are produced in more than one group (litters, clutches, etc.) and across multiple seasons (or other periods hospitable to reproduction). Iteroparous animals must, by definition, survive over multiple seasons (or periodic condition changes).


having the capacity to move from one place to another.

native range

the area in which the animal is naturally found, the region in which it is endemic.


reproduction in which eggs are released by the female; development of offspring occurs outside the mother's body.


reproduction that includes combining the genetic contribution of two individuals, a male and a female


uses touch to communicate


uses sight to communicate


Bedard, J. 1985. Evolution and characteristics of the Atlantic Alcidae. Pp. 1-51 in D Nettleship, T Birkhead, eds. The Atlantic Alcidae. London: Academic Press Inc..

Birkhead, T., M. Harris. 1985. Ecological adaptations for breeding in the Atlantic Alcidae. Pp. 205-231 in D Nettleship, T Birkhead, eds. The Atlantic Alcidae. London: Academic Press Inc..

Bradstreet, M., R. Brown. 1985. Feeding ecology of the Atlantic Alcidae. Pp. 264-318 in D Nettleship, T Birkhead, eds. The Atlantic Alcidae. London: Academic Press Inc..

Brown, R., D. Nettleship. 1984. The seabirds of northeastern North America: their present status and conservation requirements. Pp. 85-100 in J Croxall, P Evans, R Schreiber, eds. Seabirds of the world: their status and conservation. Cambridge, England: International Council for Bird Preservation.

Brown, R. 1985. The Atlantic Alcidae at sea. Pp. 384-426 in D Nettleship, T Birkhead, eds. The Atlantic Alcidae. London: Academic Press Inc..

Cairns, D. 1986. Diet and foraging ecology of Black Guillemots in northeastern Hudson Bay. Canadian Journal of Zoology, 65: 1257-1263.

Cairns, D. 1992. Diving behavior of Black Guillemots in Northeastern Hudson Bay. Colonial Watebirds, 15(2): 245-248.

Cairns, D. 1980. Nesting density, habitat structure and human disturbance as factors in black guillemot reproduction. Wilson Bulletin, 92(3): 352-361.

Gaston, A. 1985. Development of young in the Atlantic Alcidae. Pp. 319-354 in D Nettleship, T Birkhead, eds. The Atlantic Alcidae. London: Academic Press Inc..

Harris, M., T. Birkhead. 1985. Breeding ecology of the Atlantic Alcidae. Pp. 156-204 in D Nettleship, T Birkhead, eds. The Atlantic Alcidae. London: Academic Press Inc..

Hilden, O. 1994. Diurnal rhythm of colony attendance and optimal census time for the Black Guillemot Cepphus grylle in the Baltic Sea. Ornis Fennica, 71: 61-67.

Johnsgard, P. 1987. Diving birds of North America. Lincoln & London: University of Nebraska Press.

Mehlum, F., G. Gabrielsen, K. Nagy. 1993. Energy expenditure by Black guillemots (Cepphus grylle) during chick-rearing. Colonial Waterbirds, 16(1): 45-52.

Nettleship, D., P. Evans. 1985. Distribution and status of the Atlantic Alcidae. Pp. 54-154 in D Nettleship, T Birkhead, eds. The Atlantic Alcidae. London: Academic Press Inc..

Nettleship, D. 1996. Family Alcidae (Auks). Pp. 678-722 in J del Hoyo, A Elliott, J Sargatal, eds. Handbook of the birds of the world. Vol. 3. Hoatzin to Auks. Barcelona: Lynx Edicions.

Nol, E., D. Gaskin. 1986. Distribution and movements of Black guillemots (Cepphus grylle) in coastal waters of the southwestern Bay of Fundy. Canadian Journal of Zoology, 65: 2682-2689.

Stokes, D., L. Stokes. 1996. Stokes Field Guide to Birds, Eastern Region. Toronto: Little, Brown and Company.

Winn, H. 1950. The black guillemots of Kent Island, Bay of Fundy. Auk, 67: 477-485.