A couple of helpful articles from National Audubon. Check these out so you are prepared.
When You Should—and Should Not—Rescue Baby Birds
You Found a Bird That Crashed Into a Window. Now What?
One great resource for getting help when you find an sick or injured bird is the Rescue Directory found on the On the Feeder website. It is a nation-wide listing that includes many resources in our area. You can find it here: Wildlife Rescue Directory.
Calfornia Fish & Wildlife website has a list of rehabilitation facilities and includes answers to a list of wildlife rehabilitation facilities. https://wildlife.ca.gov/Conservation/Laboratories/Wildlife-Health/Rehab
The California Wildlife Center is a great resource. https://cawildlife.org/ Their Hotline Phone: (310) 458-WILD (9453)