I could see the bird quite well through my spotting scope.  Taking a clear photo, though, was a different matter.  For instance, I could see the black wingtips quite easily, however, this is hardly discernable, in the photos.  I didn't have my regular camera, so I attempted some shots with an inferior substitute.  As bad as the photos are you can still make out the fieldmarks.  The bird was actually about the same size as the ducks though noticeably larger than the nearby coots.  The camera seemed to make the goose appear larger than it actually was.  I think this is because it was getting dark at the time, and the Ross's Goose appeared very white.  The Ross's was turned so that I could see it's profile.  The ducks and coots are mainly turned facing towards are away from the camera making them look smaller.  When the Ross's was turned away, I would lose it behind a duck.  - EB