Sorry for multiple posts...
Found this site with some good summary information. I would verify everything with CDFW to be safe, but according to this site, a permit is not needed to collect rattlesnakes, nor is there a bag limit.
http://www.californiaherps.com/info/herpinglaws.html
And despite what CDFW may permit, your local municipal laws may be different. SO... don't just check with CDFW (though they would be the authority on collecting native wildlife), but also with your local county and city laws.