This den has appeared in the last week at the country park where we walk. There are always small holes dug by rabbits all over the field and you need to be careful not to put your foot down a hole as you walk. This however is something different. The opening is big and I think it's either a fox or badger. Not sure if you can tell the difference. The deep runs going into the hole look well used. Finlay stuck his head down the hole but I managed to get him to recall before he went in!!
I love finding all the evidence of wildlife where we walk. I am sure the whole field is standing on a network of tunnels dug by one or other of the animals living there.