I've also seen crows occasionally attacking GBHs, but more often I've seen
them attacked by Red-wing Blackbirds, who will attack anything up to and
including Bald Eagles. Great Blue Herons are to some extent opportunistic
predators; they can be seen occasionally hunting in farmers' fields (or
even interstate highway median strips!) far from water, and have been
reported eating mice and other small animals. I wonder if their occasional
non-fish predation might sometimes extend to the nests of other birds?
Terres mentions that they may occasionally eat rails and phalaropes, at
the end of a long list of non-fish prey. Has anyone heard about possible
predation on other bird species?

Ter Ellingson

Box 353450 ellingsn at u.washington.edu
University of Washington (206) 543-7211 voice
Seattle WA 98195 (206) 616-4098 fax

http://www.ucpress.edu/books/pages/8820.html