The first lifer of my trip was a true California specialty, the Allen's Hummingbird. It ranges from southern Oregon to southern California during the summer. This species looks very similar to the Rufous Hummingbird, and an immature like this one couldn't be told apart based on a shot like this. You'd have to look at the shape of the spread tail feathers to be sure. However, during the breeding season range is a reliable indicator, and being found in central California this is certainly an Allen's.
Another species I went in search of was the Oak Titmouse. This is very closely related to the Juniper Titmouse, which is found in Utah, and used to be considered the same species and called the Plain Titmouse. This is the best shot I could manage of this active forager, and obscures the crest that helps distinguish this species from the similar Bushtit.
The California Towhee is found from Oregon to Baja California. It is often found in coastal chaparral and can be common there. This male was singing on his territory in a small city park in the town of Pacific Grove.
Chestnut-backed Chickadees are found from Alaska to California and from the coast to Montana, but they look different here at the southern end of their range, where their flanks tend toward gray instead of the dark rufous they have further north. For example, compare it to the chickadee in this post, from Seattle.
Heerman's Gulls are also strictly coastal. They breed mostly around both coasts of Baja California, but wander north when they are not breeding, sometimes as far north as British Columbia. I think they are the most beautiful gull in North America.
Several other species are widespread along the coast, but rarely or never make it to Utah. The Black Oystercatcher is a unique shorebird that specializes on mollusks in the intertidal from Alaska to Baja. The thick red bill is used to pry open oysters, mussels, and other goodies on the rocks.
Western Gulls also breed in Baja California but their breeding range continues north through California to Washington. In Washington, they hybridize regularly with Glaucous-winged Gulls, forming a hybrid known as an "Olympic Gull." It was neat to see them in an area where most individuals are probably "pure" Westerns, with little introgression of Glaucous-winged genes.