If ground squirrels are a problem on your operation, Jim Knight, a wildlife expert at Montana State University, offers a method of control by making bait stations to place in pastures.
You can build a bait station from parts available at any plumbing supply store. It looks like an inverted T and is made from 3- or 4-inch PVC pipe. The arms of the T rest on the ground, and the stem stands upright. Mr. Knight suggests tying the stem to a fence post so it won’t tip over. Fill the stem with a general-use anticoagulant rodenticide called Ramik-Green and cover it with a lid so the poison won’t get wet. Ground squirrels find the bait by running into the arms of the T.
Mr. Knight advises placing a PVC bait station every 50 yards along the perimeter of a field and keeping it filled with Ramik-Green. Leave the bait stations out the entire summer.
Most ground squirrels that die from anticoagulants generally die underground, Mr. Knight says. If they die above ground, they should be removed.