I have attached a report of the trip I made to southern and central California in November. California is mostly visited by Brit/European birders in August and September to catch southbound migration and for seabirding however winter has a great deal to offer, flocks of wintering cranes and geese, seaduck, gulls from the north, increase in waders and less crowds in popular areas.
I have uploaded many images from this trip to my website, link below (also images from other overseas birding trips on my website.
Hopefully this may be of interest to some...
http://www.birdersplayground.co.uk/...ome%20Page.html
I've also done Texas in winter and had a great time but some of the birding in winter in California was simply superb, it doesn't have Whooping Crane though.
Hartily recommend a trip for anyone wanting a winter get away thats nice and easy.