This is a juvenile Dark-eyed Junco. I saw adult Juncos during my stay, who have black hoods and solid brown backs, but they were much less cooperative when I wanted to take pictures.
This is a Spotted Towhee. Towhees are related to sparrows. Although they were all over the place, it was hard to get pictures because they like to scurry around in bushes and stay low to the ground.
This is a California Towhee. I was really surprised to find this species here. They're very common in Southern California, but rare in the Central Valley. I guess I had assumed they could only be found farther south. Nope. They just don't like the Valley.
This is a Downy Woodpecker. They're the smallest of the woodpeckers.
This is a Common Merganser that I found in Yosemite National Park. Mergansers are related to ducks, but as you can see, they have a more streamlined body and a thinner beak. In the same river as this Merganser were a number of Mallards, including some fuzzy chicks (or "fledglings," as chicks are called once they leave the nest and learn to fly). Quite a few people were watching the Mallards dive and float about. Suddenly, this bird shows up and looks like just another duck. Since I'm used to paying close attention to birds, I notice that it is swimming underwater for a much longer period of time than the Mallards could. I call out, quite excited, "That isn't a duck!" Nearly everyone else on the bridge says, in a very resigned tone, "Yes, it is." The rest are really skeptical and ask if I'm saying it's a fish. Only I know that it's a Merganser, which is way less common than a Mallard, and a more interesting find. See? When you know some bird names, you can recognize a cool bird that slips right underneath everyone else's noses.
This is a male Brewer's Blackbird, also found in Yosemite. This blackbird can be identified by its bright yellow eyes and lack of any other color. As you can see, this male was carrying a bug, probably planning to feed it to a chick.
This is a female Brewer's Blackbird from Yosemite. Where other female blackbirds have streaky bellies or white feathers in their wings, this is just a plain brown bird with light-colored eyes.
This is a male Lesser Goldfinch. These birds are very vocal, and in the foothills I could constantly hear their squeaky song.
This is a female Lesser Goldfinch. I, personally, could not identify this bird without seeing it next to the male version. There is a species, called the American Goldfinch, whose females look almost exactly the same.
This is a Steller's Jay. This species is the only crested jay on the West Coast.
So, there you go! These are some easy-to-see birds of the Sierra Nevada foothills. There are plenty more that you could see, like American Robins, and Common Ravens, and Anna's Hummingbirds, but I wasn't lucky enough to get good photos of all those birds. See if you can recognize any of these species the next time you visit the mountains!