Ruth, Patrick and other interested tweeters,

Your bat appears to be a Hoary Bat. They are classic tree roosters and will
roost on the outer limbs of tree branches. They are also Washington's
largest bat. The most obvious feature I can see on your bat that leads me to
this ID besides the roosting behavior and size is the yellowish-orange
facial disk. These bats are highly migrational and are in the process of
migrating currently. This bat might be a migrant or be a bat that uses this
location and hasn't left yet. When I've found Hoary Bats in the past
roosting it has been in a very similar condition to yours.

Hope this helps.

Scott Downes
downess at charter.net
Yakima WA