There is a fox that lives in and around my backyard. I often see him stalking the squirrels or curling up for a nap in the sun. I guess he's here mostly for the water source - there is creek nearby.

Lately I've seen him with no fur on his tail. I know that he's a mangy, flea-ridden critter, which would explain it. I'm concerned because I figured he needs that fur to wrap around himself to keep warm. It's getting awful cold here.

So I'm considering making him a shelter. Which would be best for a fox? Should I erect a lean-to, dig a burrow, or a combination of the two? We have loads of natural materials nearby: tree logs, pine needles, bamboo, and rocks.

I'm going to do some research on this right now, but any insight or tips from you guys would be really appreciated.