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Black Guillemot

Cepphus Grylle

Population Status


In the Yukon, Black Guillemots are found only on Herschel Island where they breed at Pauline Cove. The nearest large colony is located on Cooper Island near Barrow, Alaska.

Population size:

The 2007 Herschel Island population was around 44 adults and 16 chicks.

Population trend:

The Black Guillemot population at Herschel Island and Cooper Island have experienced downward trends since the mid 1990’s. While the nesting population varies from year to year, the overall trend shows a decline. Recent counts at Herschel Island are as follows: 2005 - 60 adults and 22 chicks; 2006 - 40 adults and 13 chicks; 2007 - 44 adults and 16 chicks.

Unique or special characteristics:

Herschel Island is the only nesting site for Black Guillemots in the Yukon, and only one of a few in the western Arctic.

Habitat Features

On Herschel Island, Black Guillemots nest in artificial nesting structures on the roof and inside ceiling of the old Anglican mission building, or as it is now called, Mission House. Guillemots have also been known to nest under piles of debris or driftwood adjacent to Mission House, but this is no longer seen on Herschel Island due to nest predation by foxes. At Herschel Island, Black Guillemots are known to eat Short-horned Sculpin, Slender Eelblenny, Arctic Cod, Capelin, and Arctic Lamprey.




Travelers visiting Herschel Island, either on their own or stopping by on one of the two cruise ships that visit the island each summer, can get a tour of the Pauline Cove area which includes a walk around Mission House. Visitors learn about the ecology of the Black Guillemots as well as the ongoing research and monitoring of this species. The house has a roped barrier around it to ensure tourists do not disturb the birds in their nest boxes.


Black Guillemots nesting at Point Barrow are influenced by near-shore sea ice conditions. If the sea ice moves out away from shore early in the summer season, there is reduced availability of Arctic Cod, the guillemot’s preferred prey, and results in a decline in their nesting success. Researchers point out that this relationship between sea ice and nesting productivity illustrates a link between climate change and long-term nesting productivity. The Herschel Island population is also vulnerable to the potential impacts of oil and gas development with its associated infrastructure, as well as shipping, with their potential for spills and other contamination.

Species at Risk Status

May be at risk

Research and Monitoring

Population monitoring:

The Herschel Island population has been monitored for population and nesting since 1984. This monitoring includes a total population count of adults, counts of active nests, and a record of the success of each nest. Concern for the population arose after poor productivity in 2003 (2 chicks) and 2004 (no chicks). A program has recently been initiated to colour-band all chicks, as well as some adults. Chicks are banded with an aluminium band and a unique combination of three coloured bands so that each chick is identifiable. Adults are also banded in this way. This provides information on yearly survival and dispersal and enhances our understanding of population fluctuations. (for more information see


Researchers have been investigating numerous aspects involving the Black Guillemot, including surveying other parts of Herschel Island for nests, investigating the prey species consumed, tracking changes in population through annual total population counts of adults, and monitoring annual nesting success through nest checks during July and August. Chicks and adults are uniquely banded, weighed, and wing length is measured. Researchers also work with rangers to refine protocols for population counts and nest checks.


A better understanding of the dispersal of Black Guillemots in the Beaufort Sea region is needed. As well, researchers are trying to better understand the food requirements of nesting guillemots, and determine what factors affect food availability and breeding success.


Nesting boxes are protected and maintained annually by researchers and Herschel Island Park Rangers.

Community-based Information

Community members within the Inuvialuit Settlement Region watch for Black Guillemots and report any unusual sightings.

Related Literature and Information Sources

Eckert, C.D., 2007. Personal communication, Government of Yukon, Department of Environment.

Eckert, C. D., Cooley, D., and Gordon, R.R. 2005, Monitoring Black Guillemot population and nesting success at Herschel Island, YT, Government of Yukon, Department of Environment.

Sinclair P.H., W.A. Nixon, C.D. Eckert and N.L. Hughes (eds). 2003. Birds of the Yukon Territory. UBC Press Vancouver. 596 pp.