Before you decide it is necessary to manage your Opossum population is is important to consider that opossums usually keeps rat out of their terittory. IF you have previously had problems with rats you might prefer to keep the opossums. This is especially true since seldom become as numerous as raccons can become. Opossum are highly adaptable and are great survivors. Once they have invaded a neighborhood they are probably there to stay so long as food, water, and shelter are available.
Because they are only active at night, the animals may never be seen as they travel through neighborhoods or yards. Barking dogs and disappearing pet food left out overnight may be the first apparent clues. Evidence of them feeding and leaving half eaten fruit can also be an early clue. Sometimes strange looking droppings may be found on garden paths, walkways, and patios, though typically opossum defecate in protected and leafy areas. An occasional visit by an opossum or a family of opossum may not present cause for concern unless you have smal pets that remain outdoors at night.
The aim of habitat control is to make your premises less appealing to the opossum. Overgrown shrubbery such as Forsythia or Berberis should be cut back and trees that overhang rooftops should be trimmed back at least five feet from the roof edge. Fallen fruit should be removed frequently. Be sure your firewood is stacked tightly, leaving no major gaps suitable for a den. Scrap lumber and other items should be stored in an orderly manner, preferably about 18 inches off the ground. Garbage cans should have tight-fitting lids and food items or table scraps should not be placed in your compost bin. Food placed outdoors for pets should be removed by nightfall.
As with skunks and raccoons, the best solution to an opossum’s presence beneath stairs, porches, decks, or buildings is to screen or block it out. Close off all potential entrances or openings under the house, garden tool shed, mobile home, deck, etc. with 1/4-inch mesh hardware cloth. The advantage of using the small mesh is that it will also exclude rats and house mice.
Once an opossum has taken up residence beneath a building or deck you have to be sure the animal has left before blocking the opening. A fairly easy way to make this determination is to sprinkle a smooth layer of flour about 1/8-inch thick just in front of the point of entrance to form a tracking patch in which the animal’s footprints are evident. Examine the tracking patch soon after dark; the presence of footprints will indicate the animal has left and the opening can then be closed off. Normally opossum live alone except when with young and then, since the young remain in the pouch, they leave with the mother.
Exclusion of opossum from gardens can be accomplished with a fence built of poultry wire. The fence should be four feet high with the top 12 to 18 inches of the fence bent outward, away from the garden, and not attached to any support. Since the top of the fence is not rigid and bends under the weight of the animal, it cannot climb over it. As an alternative, any standard wire fence can be made opossum proof by stretching a parallel electrically charged wire near the top of the fence, three inches out from the mesh. A cattle-type electric fence charger activates the wire. A similar approach can be used to prevent opossum from climbing trees. More electric fence details are provided in Pest Notes: Raccoon.
Opossum are not wary of traps and can easily be caught with a box or cage-type, live-catch trap. Traps should be at least 10 x 12 x 32 inches in size and set along trails or known routes of travel. Fish-flavored canned cat food works well as trap bait but often attracts cats as well. To avoid this possibility, try using whole raw chicken eggs, or jam or peanut butter spread on a bit of bread. Other baits can include overripe fruit such as grapes, bananas, or melon. Live trapping presents the problem of dealing with the animal once captured. Since it is illegal to relocate an opossum without a permit, those not wanting to deal with its disposal may prefer to hire a professional wildlife control operator. They are equipped to handle problem wildlife in a legal and humane manner. You can find them listed under the Pest Control heading in the yellow pages of the phone book.
Other Control Methods
A motion-activated sprinkler device sometimes induces a fright response in opossum, skunks, and raccoons. If the animal has established the habit of visiting the yard or garden, such fright responses rarely last for more than a few days. A greater effect is observed on animals that have not habituated to the site.
An array of chemical products is marketed for repelling various wildlife species but, unfortunately, none offer significant results. The odor of mothballs or naphthalene crystals, used as a home remedy repellent, has occasionally been reported to be successful in driving opossum from confined areas, but can build up toxicity in the soil.
There are no registered toxicants for poisoning opossum. Poison baits sold for the control of rodents should never be used in an attempt to control opossum, skunks, or raccoons. The penalty for such pesticide misuse can be substantial and the practice usually becomes known as a result of the accidental poisoning of someone’s pet.
In rural areas where it is legal and safe to do so, opossum may be spotlighted at night and shot.