The Refuge offers sites for waterfowl hunting mid-October to
mid-January. Check the California Waterfowl Regulations each
season for opening and closing dates. All hunting areas are
boat-access only, except for Ravenswood. Additional information
is available in the Visitor Center.
Additional details here
I live pretty close to the Ravenswood area, and although I've been tempted to wander over to check it out, I haven't gotten around to it yet. I don't have a boat, though, so it's probably not usable for me.