Greetings... I saw a posting on the Kentucky birds list serve about a
photo essay on the Kentucky Ornithological Society website and thought
it might be of interest.

http://www.biology.eku.edu/kos/goose_id.htm

I've never read an article about Snow and Ross's goose ID that didn't
have "grin patch" in the text, so that's saying something, though I
don't know what. There are also some flight photos comparing the
different species and hybrids among mixed geese flocks.

Take care,
---Mike Busam
West Chester, OH