Weird pond experience

Those of you that know me and those of you who don't will understand this could only happen to me.
I have a large outdoor pond,aroun 25,000 gal. I have a huge air pump keeping it aerated and a whole in the ice. Yes it does freeze shut when it's really cold but the air is still bubbling all the time. So who cares? Well, the reason I wanted you all to know that's open is because apparently someone hasn't figured that out. There's some kind of animal with a dog type of paw that is digging a hole at the other end of the pond. It's been here two nights in a row. It has scratched the snow off a ;two foot circle and made some progress on the ice.
So any ideas? What would want to dig a hole in the ice when there's open water?
Weird huh? Go figure.

Well, where are my wildlife experts? With this melt I've been able to see the tracks "digger" left much more clearer more bettermer. They look like coyote. Too big for a fox and more rounded. He hasn't't been back so maybe he finally coed in that he wasn't going to be successful. So who knows?

Hey Seaponygirl! I'm glad it hasn't been back! I guess it avoided a fatal destiny!

-NP

Oh he's been back. Cleaed off a bigger spot. Today I saw where he cleared out a similar spot by one of our cars. So far my google search showed it Could be a red fox because of foot drag marks, clearer prints for the less hairy paw on a grey fox and the size says coyote. I'd Digger co tiniest I might get a trail camera.