>Where are some good Washington spots to observe these
>birds? Also, is time of year or time of day a consideration?

The following link:

http://www.audubon.org/chapter/wa/rainier/dipper.htm

gave me the information to find some dippers last November, behind the
picnic area in Flaming Geyser. I was there while the salmon where
spawning, and at least one dipper was dining on salmon eggs.

Roy Harvey
rmharvey at snet.net
Beacon Falls, CT