Get a 3" PVC or ABS tee and about 6 feet of the appropriate pipe and one pipe cap. Put about an 18" piece of pipe in each of the 3 holes of the tee. Tie the tee to a stake or tree so that the "branch" of the tee sits straight up. (I. E. it looks just like an upside down "T" Fill the center tube with a mix of plaster of paris (sp?) and grain. slip the cap over the end. The critters walk in the bottom from either end, eat and then walk out. The plaster of paris sets up and viola dead critter. The 3" is small enough that cats and dogs or kids cant get in, but squirrels etc can. Works great. You can also put your favorite poison in the contraption, but the plaster is just super cheap and seems to work really well.