I've had them move into a empty 5 frame nuc sitting right next to my occupied hives. But when I go out to the woods, having them close to the ground gets me nothing. Feral or wild bees are not protected, and look for a place with some security. A bear will not be as able if the bees are in a hollow branch 10 feet (3 meters) off the ground.
The zone Dr. Tom Seeley talks about in his book "Honeybee Democracy," is way up.
So at first I was perplexed by the rarity of nests high in trees. But as will be explained shortly, we now know that bees actually have a strong preference for nesting cavities with entrances located high above the ground. I also now know that my initial report of most nests being near ground level was an error generated by an unintentional bias in the way I had sampled the population of natural nests. Because the nests I studied were ones that had been noticed inadvertently by a person walking past a bee tree, and because people are much more likely to notice bees trafficking from a ground-level nest entrance than a tree-top one, I unwittingly studied nests whose entrances were far lower than is typical. I am confident on this point because several years later, when I became a bee hunter and mastered the ancient craft of lining bees (locating bee trees by baiting foragers from flowers and observing their flights back to their nests), I found that every hunt ended with me straining to spy the bees zipping in and out of a nest entrance high in a tree, like the one shown in figure 3.2. To date, I have located 27 bee trees by bee lining and can report that the average height of their nest entrances is 6.5 meters (21 feet). Needless to say, I?m now alert to the hidden danger of unintentional sampling bias.
I tie a rock around the end of a rope, and pull the trap up to around 10 or more feet. No having to fuss with ladders, I can find spots I can bicycle to, I can just walk them back on the cargo rack of the bike.
One problem that perplexes me, the species of Lemon Grass used to make the oil. I haven't fooled around with it long enough to determine, but I seem to have better luck with LGO made from Cymbopogon Citratus. Most of the stuff I find around is C. Flexuosus.