Feeding The Carnivores

When I have bones to get rid off- left over from cooking- I throw them under the big chestnut tree- and next time I look they've always gone. I wonder if the local carnivores regularly check out the spot the way the birds check out the feeders. I'd love to know who we're treating. It's a while since I saw a fox, but I think it must be something the size of a fox that took the big vertebrae I threw out yesterday.