Carol, I've never had anything do something like that so I just don't know. I'd think some kind of mammal, not a bird or some type of bug like beetle or cutworm. That does not look like cutworm to me but the extension agent said it might be a beetle when something was doing something similar to my young tomato and pepper plants. I personally think my problem was a rabbit or a rat. if it wasn't for that tulip damage a bird would be on my list. Edited to add: Marshall might put gopher on the list of suspects.
My list of suspects would be squirrel, ground squirrel or chipmunk, rabbit, or rat. I'm not sure a rabbit or rat would dig random holes, the others might, but the random holes may not be connected. Down here random holes often means an armadillo, but I think you are too far north for them. Skunks will dig random holes. I don't like groundhogs but that just doesn't quite feel like a groundhog. Can you show those photos to a local master gardener? Can you dig up that ground and smooth it to maybe get some tracks?
Other than a fence to protect them? You might try a hot pepper spray or something along those lines. Those are ornamental, not vegetable, so you don't care how they taste.
I've not had much luck with coyote urine for groundhogs but some people claim coyote or fox urine works for some critters. I found some at a True Value hardware store. It's not cheap.
That stinks. War has been declared but the cowards didn't do it in the open. They deserve to be destroyed for those bad manners.
