I've a bit of a soft spot for heermann's gulls - they're a very attractive species. On the trip birds were seen at Santa Monica and San Francisco - all the images here are from the former destination. Heermann's gull is almost exclusively coastal in all seasons, with the wintering rage extending up the California coast just north of San Francisco.
The dark brown immature bird is almost skua-like in plumage and was a bold as the waders on the shore. It's the first immature heermann's that I'd seen and none were encountered further north in San Francisco.
The non-breeding bird was on the pier (head-shot photograph), waiting for food hand-outs no doubt.
Several breeding adults were also present - I love the plumage - airbrushed qulity to the grey body and white head, vibrant red bill - very striking!