Was working in a garden today and noticed some very strange yellow jacket behavior. They were hanging out on a dwarf alberta spruce, absolutely obsessed with the thing, crawling up and down each little branch and doing something (have had too many bad experiences with these things to get closer than a foot away).

Just wondering if anyone has any theories about what they were up to...aren't they supposed to be after sugar sources this time of year? The only thing I could think of was that they were munching mites (plant's perfectly healthy, but I don't think I've ever seen a dwarf alberta spruce without at least some mites on it).