At the Northwest corner of San Francisco is Point Lobos. Just South of Point Lobos is Sutro Baths and the Cliff House Restaurant overlooking the Pacific Ocean. The magnificent view from the Cliff House includes the Seal Rocks just offshore.
The beach you see below the Cliff House in the photo above (credit Brocken Inaglory, Wikipedia Commons), is where I photographed these Heermann’s Gulls (Larus heermanni). Click on photos for full sized images.
Heermann’s Gulls form large breeding colonies on arid islands in the Gulf of California, Mexico, from March through July. The largest colony exists on Isla Raza, where an estimated 90–95% of the total world population breeds1.
Isla Rasa was declared a sanctuary in 1964, and egg-collecting and disturbance during the breeding season are discouraged. With the breeding colony concentrated on one small island this species is vulnerable to a catastrophic weather event. The success of the colony in any one year is dependent on the availability of prey and this is related to the ocean temperature changes brought about by El Niño. These factors have caused the IUCN to rate this bird as “Near Threatened”2.
These photos of adults in non-breeding plumage were taken in late September but…
The Heermann’s Gull is also known as the White-headed Gull. This photo by Basar from Wikipedia Commons shows the adult in breeding plumage.
Here are a couple of shots I took of a juvenile Heermann’s Gull on the beach.
You know what one of my favorite things is about bird blogging? It’s all of the things I learn about different birds from researching to write posts. If you want to learn a lot about bird species, I find “Birds of North America Online” the best resource on the net.
Here’s one last look at the adult Heermann’s Gull landing on the beach in San Francisco.