We put a tray of peanuts on the ground for the squirrels to keep them off the bird feeders. During the summer we saw hedgehogs eating them too and leaving the tray full of chewed up bits of nut. The squirrels eat the whole nut leaving only the husk and the great tits take the nuts away to eat. There is a cage over the tray to discourage the wood pigeons but something is eating the nuts during the night and leaving chewed up bits. Surely the hedgehogs are hibernating now? So who is eating the nuts?
It may be woodmice - although ours tend to take seeds and nuts away to stash elsewhere.
Hedgehogs do come out to rootle about in mild spells during hibernation, but could they get through the cage?
Rats more likely. They don't hibernate - not in my garden anyway. I hang assorted birdfeeders to restrict access and put limited amounts down for the ground feeding birds so there is little or nothing left each night for the rats.
The cage is A-frame and they have no trouble getting through it in the summer. The wood pigeons have great difficulty trying to fathom it out - much to our amusement!
I'm with obelixx I fear. I also try not to leave any more on the ground than will be cleared by nightfall.