There are many species of yellowjacket wasp.  A good key to NW
U.S. species, by Matthew Kweskin, Evergreen State College, can be found at
http://www.evergreen.edu/user/serv_res/research/arthropod/TESCBiota/TESCBiota.html

A publication that will answer most of your questions is the
W.S.U. publication, "Yellowjackets and Paperwasps", at
http://www.cahe.wsu.edu/infopub/eb0643/eb0643.html

Cheers,
Dave Pehling
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