HI Pete et al.:
I have been doing some research on the egret problem. I have learned
that A.a.modesta has been recorded in the Aleutian Islands, see here for
details:

http://elibrary.unm.edu/sora/wb/v38n01/p0057-p0059.pdf

Also Doug Pratt posted this to Frontiers of Bird ID listserver:

This bird looks to me like the palearctic nominate subspecies Ardea
alba alba. The best way to tell will be if it stays around until the
change to breeding colors takes place, at which time it should have a
black, or at least black-tipped, bill. This may not be a trivial
matter from a birder's perspective, because I believe the American
Egret is a strong possibility for a future split (from Palearctic
forms).

Some Australian and Eurasian references, and as a result some world
checklists, have already wrongly split the Australian modesta from
the rest of the complex, based on a DNA-DNA hybridization study that
only compared modesta and egretta. These "authorities" have
completely misinterpreted the DNA evidence and ignored other features
that clearly show that the split, if any, should be between New World
and Old World forms. For example, modesta and alba have similar soft-
part colors (modesta a bit brighter during "high breeding") and
apparently intergrade in northeastern China. A. a. egretta differs
strikingly from both at "high breeding"). If the right split occurs,
the Nisqually bird may be North America's first Great Egret (sensu
stricto).

As I stated above A.a. modesta has been recorded in the ABA area. Also
this proposed split would actually be a resplit with the New World form
being called American Egret (Area egretta). So an armchair tick might be
out there!

sincerely
--

Ian Paulsen
Bainbridge Island, WA, USA
Visit my BIRDBOOKER REPORT blog here:
http://birdbookerreport.blogspot.com/