An Arctic avian metropolis
Established in 1965, the Bylot Island Migratory Bird Sanctuary covers the entire 11,067-square-kilometer island and its adjacent waters. Much of this area is also protected within Sirmilik National Park. The sanctuary's primary purpose is to protect the immense breeding colonies of several important bird species that descend on the island for the brief Arctic summer.
The most numerous of these is the Greater Snow Goose (Chen caerulescens atlanticus). The southwestern plain of the island contains the largest known breeding colony for this subspecies. Approximately 100,000 of these geese, representing about 15% of the entire Canadian population, gather here. The population has grown dramatically from just a few thousand in the 1930s. The birds arrive in late May or early June and take advantage of the wetlands, which have many grasses and sedges that fuel their nesting and chick-rearing. The entire breeding cycle, from arrival to departure, is compressed into a frantic 70-day window before the winter ice returns.
Long-term research projects track the population dynamics of these geese. Scientists monitor nest densities, clutch sizes, and hatching success to understand the health of the population. This research also examines the impact of the geese on the tundra vegetation.
Seabird cliffs and satellite science
Beyond the tundra, the sanctuary's dramatic coastal cliffs provide nesting sites for hundreds of thousands of seabirds. At the island's northwestern tip, the cliffs of Cape Hay rise up to 460 meters from the sea and host enormous colonies of Thick-billed Murres (Uria lomvia) and Black-legged Kittiwakes (Rissa tridactyla). Combined with another major colony at Cape Graham Moore, the sanctuary supports over 300,000 murres and 50,000 kittiwakes. These numbers represent a significant portion of the birds' total Canadian populations, with estimates suggesting over 10% of Thick-billed Murres and 25% of Black-legged Kittiwakes use the island.
Scientific research on the island is extensive. A permanent research station, operated by the Centre d'études nordiques (CEN), is located in a glacial valley and supports studies on the entire ecosystem. Since 1990, a project based at Université Laval has fitted thousands of female snow geese with neck-bands to study their demographics. More recently, researchers have equipped adult female geese with GPS/GSM transmitters. These satellite trackers provide precise data on their migration routes, revealing flyways that stretch from the high Arctic, through staging grounds in southern Quebec, to wintering areas along the Atlantic coast of the United States.