Got a mystery here....
 
After extracting I have pretty much ignored my bees - which were all
doing very well until recently. Looked at my hives today - 2 of them
were totally empty of bees - not even dead ones. Both colonies were
formerly very strong, and have (still) ample stores - 80 or more pounds
of honey and pollen in the brood nest, and they all produced well this
summer (96 lbs/hive which is real good in western WA). The decline has
occurred in 2 - 4 weeks!
 
The wasps have been particularly bad and they try to get into the other
2 hives - at any one time there will be 4 or 5 wasps trying to get in.
One of these hives still has a good population (in spite of being my
weakest hive all season!) but the other has less - but still an ok
population, I hope. I haven't opened them up yet to examine brood -
that's my next step.
 
Any one recognize these symptoms? Could the wasps be to blame? I find
that unlikely since the stores were still intact. Yet the wasps have
been thickest in memory. Another irony is that I hung wasp traps
(Rescue) in front of the 2 hives that were lost. Any likely the bees
were offended and left, or that more wasps were attracted to the hives?
 
Do the bees up and leave for any reason? There haven't been any signs of
Varroa in my apiary this summer, including examining the bees
microscopically. There are no dead bees, except a few above the inner
cover. None out front either.
 
I didn't find any emergency queen cells - in fact, both hives were
requeened during the honey flow with good queens that had excellent
brood patterns.
 
Cold this be a skunk problem? I have placed chicken wire in front of the
enterences (6 - 8") of the 2 remaining hives in case that is the
problem. However, skunks aren't all that common here and I see no
evidence of scratch marks on the hive hodies. Any one have any ideas?
 
Thanks!
Casey Burns