This is, I am pretty sure, the main entrance to an armadillo den. What you see are the old roots of a long-ago fallen tree resting on the forest floor. It’s hard to tell from this photo, but dirt has been excavated from beneath those roots (and scattered on the foreground) and then the resulting hole has been packed with leaves. Clear signs of a typical armadillo den. If I had a GoPro camera and a really long
ladder stick I might send it in there to see if someone is home. But I don’t, and I didn’t.
I see a lot of these den doorways in my forest. There is even one not too far from my little cabin (which is certainly better than having one under my cabin). All of them are on the slope of the hillside, and most of them are in the south-facing slope. This one happens to be on the north-facing slope. In recent years my dillo sightings have become more common too.
Like coyotes, I understand that armadillos are expanding their range and moving north. One explanation I have read is that their biggest predator is now gone: Native Americans who used to hunt and eat the critters. I don’t know if that is true (the hunting and eating part), and I suppose there are other possible explanations, including the general warming of the hemisphere. In any case, they have not been a nuisance in my forest, and my dogs have not yet discovered them, so I’m happy to abide with them.