I can't speak to these photos but the den I found 2 years ago was a series of large holes in the ground very similar to a groundhog hole. In fact the only thing that tipped me off was the fact that there was a bunch of bones and other "toys"(squirrel tail and a duck wing) scattered around the den.Awesome photos!!
What is the actual den? Is it just the brushy cover we see in the photos?
Or is there some sort of burrow?