On Wednesday last I picked up the camera at Camera Trap Spring, closing the site for the winter, and found that two ringtails had visited that spot as well in early October.
Unfortunately, they were right at the edge of definition for the infrared flash — the batteries may have been weakening too — but I was still delighted to see them.
It is a weasel, and apparent size suggests a short-tailed weasel (ermine). But I did not think to place a vertical ruler by the water source. Any mavens of Mustelidae out there want to make a definite identification?
UPDATE: The Camera Trap Codger, who is an actual wildlife biologist, opts for long-tailed weasel in his comment — which is what I sort of thought too until I argued myself out of it.