LA Birders Webinar: Ainley’s Storm-Petrel ID, 4/11

This is one (or two) species that I had never heard of before, not that there aren’t thousands of others. Noting that it connects to a species that is a vagrant in Australia…….. Forwarded in case some Australian birders might be interested. Note that dates and times of this session are in time zone for western United States.




Dear Birders,


You are invited to the next LA Birders webinar:


Identification of Ainley’s Storm-Petrel Hydrobates cheimomnestes

with Dessi Sieburth

Tuesday, April 11 at 7:00 PM – on YouTube

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 our YouTube channel and will also be recorded for later viewing.

Become a LAB Member! Though our webinars will always remain free and available to all, members of Los Angeles Birders have access to live webinars via Zoom, invitations to special LAB-only field trips, priority sign-up on LAB field trips & events, and discounts on paid LAB programs. To learn more about membership, please see our website


Good birding,

Rebecca Marschall for Los Angeles Birders



Rebecca Fenning Marschall


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