Joan and all
I certainly agree that Grant, Gulls, A Guide to Identification, is the
definitive resource on gulls. And it is available from ABA among other
sources. My problem with Grant is I wish it had more illustrations.
Another book that I use for gulls is Seabirds, An Identification Guide by
Peter Harrison, published by Houghton-Mifflin, 1985 (revised edition). It
does contain illustrations with different age gulls. It gives you a good
idea about overall plumage X age, but there is something weird about the
illustrations. They don't look quite right. I think it's the eyes; maybe
they're too dominant.
Cheers
Gail Spitler
Johnsons Landing, BC
spitler at wkpowerlink.com