Foraging Areas of Nesting Ainley's Storm Petrel Hydrobates cheimomnestes

Acquiring basic knowledge such as at-sea distribution is often difficult for cryptic seabird species. Northern storm petrels (Hydrobatidae) are one family of seabirds that includes several cryptic species, including Ainley’s Storm Petrel Hydrobates cheimomnestes, which appears quite similar to southern Leach’s H. leucorhous and Townsend’s H. socorroensis Storm Petrels when at sea. For the first time, we describe the at-sea distribution of breeding Ainley’s Storm Petrels obtained using GPS tracking. We found that these birds visit waters of the eastern North Pacific between central Baja California, Mexico and southern Alta California, USA. These findings expand existing knowledge of the range of this species, which had previously been based on a few at-sea sightings and specimens.