Leach’s Storm PetrelOceanodroma leucorhoapopulation trends on Bon Portage Island, Canada

Abstract

Regular estimates of breeding populations are important for detecting declines and for implementing appropriate conservation measures in a timely manner. In Atlantic colonies, Leach’s Storm Petrels Oceanodroma leucorhoa are in decline at most colonies that have been surveyed. Consequently, the species has recently been uplisted from ‘Least Concern’ to ‘Vulnerable’ by the International Union for the Conservation of Nature. On Bon Portage Island, the largest Leach’s Storm Petrel colony in Nova Scotia, the last survey was completed in 2001. The aim of this study was to update the population estimate for this colony. Our results suggested that the current population is 38,916 ± 8,749 pairs, a 20% decline in 16 years. Several factors are most likely responsible for this decline, but loss of breeding habitat may be the principle cause on this island.