Photo Census Surveys of Thick-Billed Murres (Uria lomvia) at Cape Parry Migratory Bird Sanctuary, Northwest Territories

Abstract. Thick-billed Murres (Uria lomvia) are among the most numerous and well-studied seabirds in Canada; yet, there is a considerable lack of information concerning the population status of remote Canadian Arctic colonies. The only known colony of Thick-billed Murres in the western Canadian Arctic is located at the coastal cliffs of Cape Parry Migratory Bird Sanctuary, Northwest Territories. Historical estimates at this site range from 125–800 murres between 1953–1980, however, recent population data is lacking. We conducted boat-based photo census surveys between 2002–2021 to provide updated counts of murres at Cape Parry. The number of Thick-billed Murres observed at Cape Parry during our study period ranged from 570 birds in 2002 to 1,358 birds in 2019. Counts suggest the colony at Cape Parry increased considerably since establishment of the Migratory Bird Sanctuary in 1961, with less pronounced growth over the period of our study (2002–2021). As climate change and human activities rapidly transform the Arctic, monitoring and conservation of potentially vulnerable populations, such as the Cape Parry murre colony, will be increasingly important to maintain ecological integrity of marine ecosystems.