It's curious you should mention a lack of these birds at lower elevations.
I have never seen as many at higher elevations as i did this fall. There
were very large and active flocks up to 5000 ft at least until two weeks
ago. I'm used to seeing varied thrush as solitary individuals, not in
flocks of 30+.
Mary

Mary Poss, DVM, PhD
Department of Microbiology
Box 357242
University of Washington
Seattle, WA
mposs at u.washington.edu