Control of 'rodents', by which I mean to include deer, hare, moles, possum, raccoons, squirrels, skunks, and woodchucks, is limited in urban areas to simple discouragement provided by fencing them out. The use of firearms is prohibited. Trapping and relocating is prohibited. Can you trust your neighbors to turn a blind eye when you are trying to protect your investment in your property? Will the police believe your claim that the 'rodent' must have been rabid to have attacked you, and you were forced to protect yourself? Of course not; your neighbor reported that you were chasing the poor defenseless animal all over the place, firing wildly, without concern for life or limb on adjacent properties. Unwelcome intruders are the scourge of the homeowner whose investment in gardening extends his or her 'personal space' into the unprotected out-of-doors.
Whether the intruders are 'rodents', stray domestic pets, or the neighborhood children, the keep-'em-out solution is fencing. If you cannot, for zoning, esthetic, or just principle, install fencing, you are faced with but three choices: learn to share your garden with intruders, give up gardening except for a few foundation shrubs and trees, or take your love of gardening indoors. Most urban dwellers accept those conditions and live the unfortunate lives of never having tasted good food. My condolences.
So, how good can fencing be anyway? All the 'rodents' can climb or jump over anything. You cannot install fencing underground to keep out the moles and other excavators, and you cannot build fencing high enough to discourage the climbers. How does fencing work?
Fencing is not just a physical barrier. It is a territorial boundary. It is a hazard. In the day-to-day search for food, the 'rodents' have only so much energy to expend, and are quite conscious of what an injury they might sustain would mean to their families. While they appear to be lazy, they are really balancing energy and risk against the prospect of success in finding food. There is constant pressure from their expanding populations against your perimeter fencing, and incursions from time-to-time are unavoidable. Desirable new territories must hold habitat, shelter, and food; if your property is clean, and without opportunity, the explorers will look elsewhere. Therefore, your first line of defense is perimeter fencing, and the second is a property that is free of opportunity. Holes excavated underneath perimeter fencing must be filled as soon as dug. Broken fence boards and other components must be replaced today, not when you can get around to it. Over time, your well maintained perimeter fencing will keep out all who have found the interior of the property to be of but little interest.
If you are growing vegetables, your property becomes attractive overnite. Corn, beans, and melons are irresistible to 'rodents'. Once these exposed crops have been discovered, then your intruders will be back night after night to check on their crops. Fencing around your vegetable garden is essential, but it does not work the same way as perimeter fencing; after all, food is known to be on the other side of that barrier. I use low current electric wires to supplement garden fencing, and have eliminated all types of nightime explorers all of the time. I run the wires at two different levels. The first is at a height of 12 to 15 inches above the top of the fence. That course persuades the 'deer rodents' that jumping over the fence may lead to other unpleasantness. The second is a few inches below the level of the top of the fence, and about four inches away from the fence. That wire prevents the climbers from entering the garden. Note that the fence is grounded and the wire is hot. It is important to place the wire at least four inches from the fence and four inches below the top rail so that the gap cannot be bridged by birds, as they would be killed. Birds are very sensitive to electric current, more so than any of your 'rodent's who receive only a slight stinging sensation, harmless but unpleasant. My electric controller is a simple transformer which steps up the house line voltage to about 1000 volts ac. In the process, the current carrying capability at that voltage is reduced to less than one amp. I can grab hold of the hot wire for several seconds; it is unpleasant, but not enough to mark the skin. The controller costs $25. and is a simple affair to install. I use 150# stainless steel stranded fishing wire which is about $9. for 300 ft. Since the electric wires are not connected to perimeter fencing, no warning signs, and no permits are required.
Spot fencing is that which you place around saplings and other sensitive plants, both to deter the 'rodents', and to limit lawnmower and string trimmer damage caused by careless helpers. Usually put in place in late fall, spot fencing needs to be tall enough to keep rabbits away when the snow is deep.
When Mole Hills become Mountains -- is Bob Stewart's take on moles, and his collection of anecdotal remedies for their control and/or elimination.
One last solution offered tongue-in-cheek is the acquisition of a dog, not just any dog, but a Jack Russell Terrier. They have proved to be excellent deterrents, especially for rabbits, moles, and squirrels. On the up side: you can dispense with all types of fencing, except perhaps the underground electronic barrier that shocks your new pet if it tries to wander off the property. On the down side: during the chase, a dog can destroy more plants than the 'rodent' could damage unmolested. And, adding up the cost of acquisition, training, worming, food, and that electronic barrier, you will have spent as much as if you had purchased that trouble free low-maintenance fencing.
If you grow berries, cherries, or grapes, you will have to contend with bird netting for control, but only from ripening to harvest. In the case of blueberries, I prefer permanent heavy gauge plastic mesh with one inch squares to give easy access to the bumblebees and wrens while excluding all others. It happens that I grow my grapes and watermelons in the same patch, and require electric and garden fencing and bird netting, but only during August and September.
It would be remiss of me not to mention nature's balance once again. Small mammals are part of the grand plan. Hedgehogs destroy earwigs, raccoons eat grubs, and skunks eat the equivalent of their own weight several times a week in harmful moths, grasshoppers, snails, slugs, grubs, gophers, and mice. Moles feed on japanese beetle grubs and a variety of other insects. They can consume as many as 200 sawfly cocoons per day. The shrew has an even better record. It can gobble its own weight in grubs and cutworms in just 3 hours, and has been observed to eat over three times its own body weight day after day. This is why fencing critical areas is the most effective control measure you can employ.
Destroying small mammal populations is destructive of the environment; and I consider it anti-gardening. However, in urban settings, these populations can quickly expand to nuisance proportions in the absence of their natural predators. Most municipalities have ordinances against trapping and relocating 'rodents'. Some states with serious urban pest problems have begun consideration of moderating homeowner restrictions. The Illinois Department of Natural Resources (fall 1998) has revised nuisance wildlife rules to allow euthanization of raccoons and skunks, with hopes that humane methodologies be found. If you are an Illinois resident homeowner, a permit will be issued for this purpose, if you contact the biologist in charge of your County, and if you have the correct answers to his or her questions. Personally, I think that re-introduction of cougars and coyotes might be more helpful, though quite unworkable. Professional exterminators received numerous calls this year for removal of ladybugs seeking warm places for winter hibernation. If the American public freaks-out at the sight of a bee or a ladybug, one can imagine the outcry if a natural predator should be spotted during daylight hours. Yet, the hawks that menace my songbird insect eaters fail to draw the same kind of attention. Left alone, nature will provide the proper balance, but it is our destiny to interfere with nature at every opportunity.