I've found trapping and relocation, or shooting them if that fails are the only control measures that work. 1 can decimate an entire garden in an evening. I believe in live and let live , but all the labor I put into my garden is not for the ground hogs, nor will I give up my garden to this sometimes cute but insidious beast.
Many are easy to catch in a HavAHart using cantaloupe as bait, most find it irresistible, but a few will not be baited.
