We have discovered what was taking the rabbit treats out of the traps. Mice. The wildlife camera picked one up, a little moving blob entering the cage through the wire mesh, then exiting a moment later towards the cover of the shrubs at the back of the bed at tremendous speed. It must have held the entire biscuit clamped between its jaws, to run that fast while carrying it, though the image was too small and blurry to be sure. The mice didn't hang about before making their move either, since the clip was timed barely an hour after dark. At least my curiosity is gratified, and photographing a mouse in action proves that the camera was working. There were no images of rabbits.
I don't think they are regularly coming in from the top, I think they are spreading out from their fastness underneath the rose bank and the deck. Tonight the camera is trained on the edge of the further deck, and my newly baited trap, not using biscuits. The wild rabbits might or might not like pet treats, but the evidence so far is that the mice will get there first. Instead I am back to carrots.
Our neighbour the retired apple farmer called around with the parish magazine, and as I bounded out of the house because I still haven't paid for 2016 we fell into conversation, initially about tulips and thence to rabbits via what it might have been that decapitated some of his tulips. Once he had checked that I was not having him on when I claimed to have bought pet treats to bait my rabbit traps, he explained that if using carrots I needed to cut them up, and lay a trail of pieces towards the trap. It was not easy to get rabbits to enter traps, but he had done it using carrots. I defer to his experience. He has lived on the farm all his life, and if you want to know about pest control ask a farmer. So we shall see tonight whether the rabbits take any notice of the carrot* segments whatsoever, or go hippity-hoppitying past them in search of nicer food, like sweet violets and Geranium maculatum.
The Systems Administrator saw one and possibly two on the top lawn after the rain had stopped, but they moved out of sight before the SA was ready with the gun. I have agreed to trim the top of a prostrate yew that's obscuring the line of fire from the bedroom window. Thus do we drift towards madness. Memo to self: do not pour gasoline down any holes and set light to it. It could be time to reread Second Nature very soon.
*AKA POV - Popular Orange Vegetable