Date: 8/20/26 9:43 am From: Joe Morlan via groups.io <jmorlan...> Subject: [pen-bird] Heermann's Gull (Larus heermanni) - Juvenile
17 August 2026. San Gregorio State Beach, San Gregorio, California, USA.
This one had me scratching my head. I have never before encountered this
plumage as it is not normally seen away from breeding colonies. It is a
juvenile with bleached pale fringing on its mantle, scapulars and tertials.
They breed primarily in Mexico with only one known California colony at
Robert's Lake, Seaside, 80 miles to the South. It is an open question
whether this bird came from that tiny colony, or from another closer
unknown breeding site? We see plenty of uniformly dark gray-brown immatures
from Mexico, but not juveniles. Dark legs and grayish foreneck help
distinguish it from similar species. I'd be interested in hearing any
additional sightings of this individual or other recently fledged juvenile
Heermann's Gulls.
--
Joseph Morlan, Pacifica, CA
