Tweet tweet bird

We live in Hemet,Ca. Zone 9. Love all the birds we see in our area. Within the last 2 months we have heard a bird, not seen yet, that simply has a Tweet,tweet sound. Could anyone identify this bird or tell us where to look to find this bird sound?

Thanks for your help.
Sylvia

Here is a list A-Z of birds that can be found in California, it also has the birds song and call's. If you heard this bird around your yard I would start with Song birds and Warbler's. Not an easy task but you may find your bird that way, or you could wait and try to catch a look at it or even get a photo.

http://www.whatbird.com/browse/objs/All/birds_na_147/38/Location/275/California

Try looking up an Oak Titmouse on the link Burd gave you.

Thanks for your help. I found it it's a Wilsons Warbler.
Sylvia