Ainley's Storm-Petrel Hydrobates cheimomnestes Scientific name definitions

Ainley's Storm-Petrel shares with Townsend's Storm-Petrel (Hydrobates socorroensis) a very restricted breeding distribution, on a few islets at the southern end of Guadalupe Island, off the northwestern coast of Mexico. Although these two species share the same islets, they scarcely overlap, because each species breed at a different time of year. Ainley's Storm-Petrel breeds in winter, presumably between October and April. In addition to this temporal segregation, these two storm-petrels have differences in vocalizations, and also have a subtle size and plumage differences. Very little is known about the nonbreeding distribution of these species, due to their similarities to each other and to Leach's Storm-Petrel (Hydrobates leucorhous). For example, it was only recently described for U.S. waters. It is thought that Ainley's Storm-Petrel migrates to the south, occurring as far as near Galapagos.