Black Guillemot (Cepphus grylle)

Black Guillemot

[order] CHARADRIIFORMES | [family] Alcidae | [latin] Cepphus grylle | [UK] Black Guillemot | [FR] Guillemot a miroir | [DE] Gryllteiste | [ES] Arao aliblanco | [NL] Zwarte Zeekoet

Subspecies

Genus Species subspecies Breeding Range Breeding Range 2 Non Breeding Range
Cepphus grylle NA, EU n coasts n oceans
Cepphus grylle arcticus ne USA, se Canada and s Greenland to the British Isles, s Scandinavia and the White Sea
Cepphus grylle faeroeensis Faroe Is.
Cepphus grylle grylle Baltic Sea
Cepphus grylle islandicus Iceland
Cepphus grylle mandtii ne Canada to Svalbard to n Siberis and n Alaska

Physical charateristics

The Black Guillemot (Cepphus grylle) is a striking
bird with almost entirely black breeding plumage, a bright,
white patch on the upper wing and spotless, white
underwings. Its plumage is set off with bright red legs and
feet, a slender black bill, and a coral red mouth-lining.

Listen to the sound of Black Guillemot

[audio:http://www.aviflevoland.nl/sounddb/B/Black Guillemot.mp3]

Copyright remark: Most sounds derived from xeno-canto

wingspan min.: 50 cm wingspan max.: 56 cm
size min.: 30 cm size max.: 32 cm
incubation min.: 22 days incubation max.: 24 days
fledging min.: 38 days fledging max.: 24 days
broods: 1   eggs min.: 1  
      eggs max.: 2  

Range

North America, Eurasia : North coasts

Habitat

Black Guillemots are an ice-dependent (pagophilic) species. Their survival is inextricably tied to the arctic pack ice. Satellite observations indicate a decrease in the extent of ice cover of nearly three percent per decade since the late 1970s, with the rate of loss accelerating this decade. Changes in Black Guillemot colonization and populations in the western arctic are already among the first documented biological effects of climate change. Typically, the species nests in crevices on rocky sea cliffs or in cavities found on rocky shorelines or headlands. They require a minimum of 80 snow-free days for laying eggs, hatching their young, and for the fledglings to leave the nest.

Reproduction

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.
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.

Feeding habits

Black Guillemots eat all kinds of animals from the sea, including crustaceans (crabs and shrimp), mollusks (clams and snails), and worms. They can dive 50-60 meter deep.
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.

Conservation

This species has an extremely large range, and hence does not approach the thresholds for Vulnerable under the range size criterion (Extent of Occurrence <20,000 km2 combined with a declining or fluctuating range size, habitat extent/quality, or population size and a small number of locations or severe fragmentation). The population trend appears to be increasing, and hence the species does not approach the thresholds for Vulnerable under the population trend criterion (>30% decline over ten years or three generations). The population size is very large, and hence does not approach the thresholds for Vulnerable under the population size criterion (<10,000 mature individuals with a continuing decline estimated to be >10% in ten years or three generations, or with a specified population structure). For these reasons the species is evaluated as Least Concern.
Cepphus grylle is a widespread breeder in coastal areas of northern Europe, which
constitutes >50% of its global breeding range. Its European breeding population is
large (>130,000 pairs), but underwent a moderate decline between 1970-1990. Although
the populations in Norway and Sweden continued to decline during 1990-2000, the
species was stable, fluctuated or increased across most of its European range, and
remained stable overall. Nevertheless, its population has not yet recovered to the level
that preceded its decline.
The breeding distribution of Black Guillemots is circumpolar. They nest from the Gulf of Maine northward throughout eastern Canada, over most of the Canadian Arctic Archipelago, north to Greenland, and across Eurasia. There are also isolated colonies in northern Alaska and the Yukon Territory in Canada.
Black Guillemot status Least Concern

Migration

Resident and mostly sedentary except in Northern regions, where movement to adjacent ice-free waters occurs. In general, winter distribution of adults essentially the same as breeding, with concentrations at traditional locations to moult, usually in sheltered waters near colony, where they spend the winter. Juveniles often move considerable distance from natal sites, usually in direction of prevailing sea currents. Reasons for their long distance dispersal are unclear. The overall dispersal patterns of the various populations poorly known, particularly in remote and inaccessible regions.

Distribution map

Black Guillemot distribution range map

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