Modeling foraging range for breeding colonies of thick-billed murres Uria lomvia in the Eastern Canadian Arctic and potential overlap with industrial development

Mapping areas of conservation concern for wildlife in the Arctic is urgently required to evaluate the impact of accelerating development in northern regions. There is substantial evidence that large seabird colonies reduce the availability of food in adjacent waters, creating a zone known as “Ashmole's Halo”. Given the existence of the halo, Central Place Foraging theory (CPF) allows us to make predictions about the distribution of food and birds at different distances from the colony. Using a time-budget approach and a CPF framework, we modeled the relationships between foraging range and colony size for thick-billed murre colonies in Eastern Canada and calibrated these predictions against foraging trip distances recorded by GPS loggers attached to incubating birds at two colonies differing in population size by an order of magnitude. Our results support the general predictions of CPF and allow us to predict maximum foraging ranges for Canadian Eastern Arctic colonies, enabling us to map likely zones of overlap between the foraging of breeding birds and future development activities in Canadian Arctic marine waters. A similar approach could be used for many seabird species where the majority of breeding birds occupy a small number of discrete colonies.