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).

Biogeographic Regions: arctic ocean (Native ); atlantic ocean (Native )

occurs (regularly, as a native taxon) in multiple nations

Canada

Origin: Native

Regularity: Regularly occurring

Currently: Present

Confidence: Confident

Type of Residency: Year-round

United States

Origin: Native

Regularity: Regularly occurring

Currently: Present

Confidence: Confident

Type of Residency: Year-round

Global Range: (>2,500,000 square km (greater than 1,000,000 square miles)) Breeding range extends from the eastern Canadian Arctic and western Greenland south to the Gulf of Maine, east to the northern British Isles, Scandanavia, and Baltic Sea, and east along northern Russia to the Chukchi and Beaufort seas, including Alaska (Butler and Buckley 2002). In winter, most tend to stay near breeding areas (if open water is available).

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.

Length: 33 cm

Weight: 428 grams

• Terrestrial
• Marine

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).

Aquatic Biomes: coastal

Comments: Black guillemots nest in holes under rocks (rarely in ground) on rocky islands, among boulders at base of coastal cliffs, in or under beach flotsam and other human debris (e.g., in northern Alaska), or in coastal cliff crevices. Females tend to nest in the same site in successive years. In winter, they inhabit rocky seacoasts, open sea, or margins of landfast ice, seldom far from shore.

Non-Migrant: No. All populations of this species make significant seasonal migrations.

Locally Migrant: Yes. At least some populations of this species make local extended movements (generally less than 200 km) at particular times of the year (e.g., to breeding or wintering grounds, to hibernation sites).

Locally Migrant: No. No populations of this species make annual migrations of over 200 km.

Young move away from breeding site in direction of prevailing current; see Brown (1985) for details for western Atlantic and elsewhere.

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).

Comments: Eats small fishes and invertebrates found on or near bottom in shallow water or in deeper water near pack ice. Chicks are fed mainly fishes (and invertebrates in high arctic. Forages close to colony (usually 4 km or less).

Black guillemots feed by diving underwater in relatively shallow water (usually less than 50 meters deep). Dives last up to 2.5 minutes but usually are closer to 1 minute in duration, depending on water depth.

Note: For many non-migratory species, occurrences are roughly equivalent to populations.

Estimated Number of Occurrences: > 300

Comments: Many occurrences throughout northern waters, primarily in the eastern Arctic and north Atlantic.

100,000 to >1,000,000 individuals

Comments: Global breeding population estimated to be 500,000 to 1,000,000 (Gaston and Jones 1998). Accurate census extremely difficult (Butler and Buckley 2002). Censuses in 1970s and early 1980s yielded estimate of about 5000 pairs in New England, about 70,000 in eastern Canada (Nettleship and Evans 1985). A few hundred in Alaska (Lensink 1984). See Evans (1984) for population data from Greenland.

Despite larger clutch size, breeding success (about 0.6-0.8 young fledged per pair) is similar to that one other alcids that lay only 1 egg (Harris and Birkhead 1985).

Average lifespan

Status: wild: 157 months.

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 time to hatching: 25 days.

Average eggs per season: 2.

Eggs are laid mainly in May-June in southeastern Canada, late June-early July in Beaufort Sea area (Johnson and Herter 1989). Clutch size is 1-2. Incubation, by both sexes, lasts 23-39 days (average 4-4.5 weeks). Young are tended by both parents; most leave the nest area and are independent by 31-51 days. Individuals first breed at an age of 2+ years. Nesting usually occurs in small groups or as single pairs.

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).

US Federal List: no special status

CITES: no special status

IUCN Red List of Threatened Species: least concern

Canada

Rounded National Status Rank: N5B,N5N : N5B: Secure - Breeding, N5N: Secure - Nonbreeding

United States

Rounded National Status Rank: N4 - Apparently Secure

Rounded Global Status Rank: G5 - Secure

Reasons: Widespread; most regions report stable or increasing populations, following earlier declines.

Global Short Term Trend: Increase of 10 to >25%

Comments: Increased in the Gulf of St. Lawrence region in the 1980s (Chapdelaine and Brousseau 1992). Stable or increasing in southern part of northwestern Europe; predation by introduced mink has caused some local declines in northwestern Europe (Evans 1984). Apparently has become more abundant in Beaufort Sea area in recent decades because of ability to nest in made-made beach debris (Johnson and Herter 1989); however, this trend has recently reversed, possibly the result of global warming (Butler and Buckley 2002).

Management Requirements: See Evans and Nettleship (1985) for research and management recommendations.

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).

Comments: Hunted in Greenland (Evans 1984).

Comments: Constitutes a superspecies with Columba and possibly C. CARBO of Asia (AOU 1998).