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[mangodance <bmn@iglou.com>]

Yellow jackets (several species) will make subterranean nests, nests in 
logs, standing living and/or dead trees, aerial nests, and even nests in 
rockfall areas.  Never underestimate them...I can tell you that!  <grin>

BTW, you are correct in that bald-faced hornets (not true hornets at 
all...but wasps) do nest aerially and are usually what people refer to 
when recalling aerial nests.  I can unfortunately also tell you not to 
underestimate them either!  :(