Natural history of the backyard foxes

It turns out that the best feature of our backyard is not the vegetable garden or the array of bird feeders. It is a hole.

A couple of years ago, we removed a dying ash tree from the center of our yard. Its roots must have been rotting away in some places, creating a small sinkhole just big enough to twist your ankle.

Summer before last (or, maybe two years ago) bumblebees nester there, creating endless entertainment watching the bumbling around pollinating our wildflowers and flying in figure-8 patterns in and out of their nest. 

After they moved out, moles or voles moved in. Sometimes at night, we hear desperate squeaking noises. Which, up until this morning, I usually assumed that these noises are made in response to the prowlings of our neighborhood cats. Now I'm wondering if these foxes have been coming around more frequently! 

Last time we saw them was maybe 7-8 years ago. Sorry, tiny burrowing mammals, but I can't wait to see what other life this hole brings to our yard.