Cook’s Petrel at San Onofre Nuclear Generating Station

Dear friends,

Yesterday Jimmy McMorran kindly delivered to the San Diego Natural History Museum the Cook’s Petrel that was found dead within the decommissioned San Onofre Nuclear Generating Station on 8 August. As soon as it was thawed out, I prepared it as a study skin and partial skeleton, taking a tissue sample for archiving at SDSU. The bird was an immature female in extensive body molt. Some rectrices were growing, but there was no molt in the primaries or secondaries. The bird was quite fat and was evidently healthy when it somehow flew ashore (at night?) and apparently collided with some obstacle in the station. A small patch of feathers was missing on the right side of the nape and rear of the head, and there had been much subcutaneous bleeding in this area. The bird agrees with our other specimens of Cook’s Petrel in color, size, and bill shape (slender, not thick as in Pterodroma defilippiana).

Though Cook’s Petrel, which breeds on islands around New Zealand, has been seen regularly off San Diego County since 2020 (a shift in its range in response to changing ocean conditions?), it typically occurs over the deep ocean beyond the continental shelf, at least off California. The specimen from San Onofre is the first to be preserved from San Diego County and, as far as I know, anywhere in southern California. According to a search via vertnet.org, California’s three previous specimens were from Santa Cruz on 17 November 1983, Monterey County on 13 August 2010 (both now in the California Academy of Sciences, San Francisco), and off Eureka on 14 September 2013 (now in the collection of Humboldt State University). Of course, there may be additional recent specimens, as the Vertnet database is not updated in real time.

Thanks to Jimmy McMorran for identifying this specimen and getting it to the museum as quickly as possible.

Good birding,

Philip Unitt

San Diego