Our west coast finches are easy to confuse. In this little guide, I tried to put the similar male and female species together so you can scan back and forth to see the differences. The hardest birds for me were the American vs Lesser goldfinch females. I think looking at the wing bars vs that little white dot below the primaries on the Lesser goldfinch is really helpful there. Also, the Purple and House finch are difficult to tell apart as well without a bit of careful study.

If you are looking for more small birds, check this guide, and if you are looking for sparrow ID help, this guide is for you.