I'm in Southern California. Hearing lots of birds, don't know one sound from another.

"Tweet, tweet," is a generic expression of what birds "say." However, there is a bird in the area which actually says, "tweet, tweet." Any ideas what it could be? We have jays, doves and mocking birds of course, crows, Bewick's wren and California towhee. Those are the only local birds I know.