So here's what I have going. Some of you may have seen my last post about the otter in my lake. Well I caught one on the sword fish head. So last night I paddled around in the canoe looking for sign of more otter I found a hole in the bank where half of the whole was out of the water and the water going in and out was muddy. So I put a 160 in front of it. That's all I have besides 330s I noticed a small air hole up on the bank. I honestly thought muskrat by the hole size but knew it could still be otter. This morning I went to check and the trap was untouched but what ever critter was in there dug out of the air hole to avoid the trap. What are your thoughts? I'm not an otter trapper but this screams otter to me. Should I dig the air hole out big enough to slip a no.5 bridger coil spring in there ?

How deep is the water at the entrance?

Probably a muskrat. They make those tunnels to get to the top of the bank kind of like a mole. It was probably in the tunnel after you set the trap and just finished his tunnel to the top.
It would still be a good idea to leave your trap there. Everything eats muskrats