If it is a new hole and you have water access it might be possible to flood them out. I’ve used large irrigation lines before but a dozen or more full 5 gallon buckets dumped in real fast would probably do the trick.
I guess I know why it was closed without anything in it. I got a rat this morning. Son of a b***h seems to have been attracted to the area by my compost bin and there’s a perfect habitat in the unkept/wild yard that’s adjacent to that garden. I made a dumb mistake with the compost bin, I bought the hardware cloth today and will fix it by putting under the bin tomorrow or Monday. The trap’s out again to see if I can get the rest of his family.
No luck here, I caught a big bird but no woodchucks. The guy just dug another hole to get back into the porch; he didn’t show up for several weeks there. My guess is its just a mid-day hideout for him, otherwise I’d see more entry signs.
I put a Havaheart trap under a Korean Giant pear tree and baited my groundhog with its favorite fruit, Asian pears.
What did it do? it ate around the trap and climbed up the tree to choose the fruitit wanted. This darn animal is so hard to catch.
Have you tried covering the trap to make it dark? To most people a dark hole is not inviting but to a groundhog that feels safest underground it might make the wire trap look less threatening and more of a safe haven.