In the photo below, once again you're looking for one bird that's different from the others, in this case distinguished by its smaller size:
In 2004, the smaller-bodied subspecies of Canada Geese (Branta canadensis) were formally split off as a separate species. They're now known as Cackling Geese (Branta hutchinsii). [If you don't have a field guide published after 2004, this species won't appear in your book.]
On 19 January 2013, a small flock of geese flew over me while I was standing on the tidal flats in Bodega Harbor. One goose was much smaller than the rest.
Along with the overall smaller size, note the more rounded head; stubbier bill; shorter neck; and darker breast.
I don't know a lot about Cackling Geese, but it seemed worth documenting their presence in Bodega Harbor and their addition to the local species list.
If you want to practice locating the Cackling Goose among the Canada Geese, here's a slightly different view:
[The Cackling Goose is the second bird from the right.]
ADDENDUM (13 February 2013): I should I have clarified that it's not necessarily the first time a Cackling Goose has been observed in Bodega Bay. I would have to check, but I'm guessing others have probably identified them locally. But this is the first time I've seen and photographed one in the harbor, and that I recognized we needed to add it to the local species list. If you're interested in reviewing that list, it's posted online here: http://bml.ucdavis.edu/bmr/Bird_List.PDF