I vote human, someone who scouts the tree regularly, someone with one of those extend-a-pole fruit picker tools and/or a nimble tree climber is the most likely culprit. I base this on the overwhelmingly constant theme of the trees being picked clean. The lack of partially eaten fruit seems to make this "overnight vanishing" unlikely to be attributed to wildlife. Their discerning taste would have them toss fruit that was not perfectly ripe, when faced with such abundance. Humans would just grab the lot and deal with under/over ripe fruit later.
Most critters noses are hundreds if not thousands of times greater at scenting when fruit is optimal for instant consumption. Most of these same critters "remember" when and where the fruit party was LAST year and will happily avail themselves of the bounty on an annual basis. So yes, absolutely raccoons will clean out grapes, plums etc., but over many evening raids, over the
course of a week or more...a flock of birds will clean out a cherry tree, but over many days, at least that is my
experience.
The fact that the entire crop vanishes over a single night is the biggest "hmmmm" here. It is theoretically possible multiple species working in concert, with the ground critters (deer, skunk etc.) cleaning up what others (raccoon, possum, rodent) drop could strip a tree bare with no damage, but over a week, not a single night, and not without SOME evidence (partially eaten fruit, scat, claw/hoof marks...) betraying their presence.
Neither raccoon or possum would carry off/stock pile fruit; skunks, deer and other
land based critters could not access the high stuff. Birds, such as crows would possibly carry fruit off, but I would think a mass onslaught would only happen in daylight and create quite a ruckus.
In my experience, raccoons, and birds are picky, and will discard fruit that is not at their desired level of ripeness, leaving plenty of evidence behind in the form of partially eaten fruit; and all that gorging is certain to lead to fecal deposits that would clearly show what they had been eating.
Sure the raccoon/possum/deer/bird/rodent leftovers may have have been cleaned up by other animals, but not to the point of zero trace/evidence, in a single night.
I do not think there is a single
answer; each situation, although sounding identical, likely has different or a variety of thieves at work. But the biggest key is what if anything is left behind as debris - a raccoon sitting there may "look" guilty, but an absence of partially eaten fruit belies that assumption. For the most part, based on the descriptions noted in this
thread, a very efficient human or group of humans is most likely the true culprit.
Assuming these trees do not have a handy structure nearby, I would be tempted to load the ground with dog, cow or horse feces to deter the humans AND create "track traps"! I doubt in the dark they could avoid all the fresh shit and NOT leave footprints. Perhaps this would deter humans from nocturnal thievery? I would also post signs warning of newly installed security features designed to protect YOUR crops; perhaps the dog is automatically "released" when security measures are triggered?
A game cam would also work great (although to my mind not nearly as satisfying without the addition of one of these more diabolical options, just saying...), as would any sort of motion activated
lights, alarms or
water cannon/sprinkler.