I have lost 2 hives now, and my thirds looks like its going down, too, due to yellow jackets. I am not quite sure if you can lose a hive to yellow jackets as in all my reading on the threads here say a healthy large hive can fend them off. Yet, two weeks ago when I did a hive check, all my hives were doing well...two were thriving and the third had a good population but no honey/pollen stores. This hive I started feeding with top feeders to increase there stores. All was well until a week ago when I noticed robber bees around the yard. I reduced entrances in the hive being fed and then the yellow jackets started. This hive went down fast and then my second hive which had plenty of stores and population started being inundated with yellow jackets. I put up traps (homemade, storebrought with apple juice, store bought with phermone/hotdogs), I started getting out my fly swatter and then I took apart this hive a week ago and it was gone,too. MY third hive, by far my largest and most boomiest, is now not doing well. At first, the bees seemed to be fighting off the attack and it looked like it would survive. But weather hasn't been in my favor, 45 F mornings which are no problem for yellow jacket flying and carnage, keep the bees indoors so by the time it warms up the yellow jackets have been attacking the hive for hours. The same at night - they keep going after the sun in down and the bees have gone in. Now it looks like more yellow jackets are coming in and out of the hive more than bees, and I have reduced the entrance to 1 bee width. So sadly, it looks like I am losing my last hive.
So here is my question: can you lose hives to yellow jackets only or should I suspect that my hives were weakened by something else?
If/when I get bees again how can I stop this from happening again? The yellow jackets are relentless and there are so many of them. I don't have any nests on my property (we checked) so I can't go out and kill the source. What precautions do you other beekeepers take?