You are invited to the next LA Birders webinar:
Identification of Ainley's Storm-Petrel
with Dessi Sieburth
Tuesday, April 11 at 7:00 PM –
Once considered a single species, the Leach’s Storm-Petrel was split into three species in 2016: Leach’s Storm-Petrel, Townsend’s Storm-Petrel, and Ainley’s Storm-Petrel. Although
Townsend’s Storm-Petrel can be identified in the field, very little is known about how to identify an Ainley’s Storm-Petrel. They differ from Leach’s Storm-Petrels in only two regards—their vocalizations and the fact that they breed in the winter.
Storm-Petrels spend nearly all of their time on the ocean hundreds of miles offshore, visiting land only a couple months out the year to breed. Therefore, birders are mostly likely
to encounter Storm-Petrels on the ocean, where their vocalizations and time of breeding are useless for identification.
Is it possible to identify an Ainley’s Storm-Petrel at sea? The answer may lie in their time of breeding. Birds generally replace their feathers at a time of year opposite to breeding.
Because Ainley’s Storm-Petrels breed in the winter, and Leach’s Storm-Petrels breed in the summer, it can be inferred that Ainley’s Storm-Petrel would replace their feathers at opposite times of year, too. This field mark could potentially be useful for identification
of Ainley’s Storm-Petrel at sea.
Dessi examined Storm-Petrel specimens to see if he could find any specimens replacing feathers at an atypical time.
Join Dessi as he discusses identification of Ainley’s Storm-Petrel.
This webinar will be livestreamed on
YouTube channel and will also be recorded for later viewing.
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Rebecca Marschall for Los Angeles Birders
Rebecca Fenning Marschall