By MATT MAURY

Many homeowners have experienced the presence of unwanted guests at their homes - members of the animal kingdom that have decided to take up residence on the premises. Birds, moles, rats, squirrels, raccoons and their kin arrive without warning. That's when to call for help in evicting the unwanted tenants. Here's how pest control contractors can assist in specific situations:

BIRDS

Problems with birds fall into three categories: nests in undesirable locations, woodpeckers pecking and fowls fouling.

Birds' nests that appear under eves and in attics can be prevented by taking action at this time of year. Air vents and other points of entry should be screened with wire mesh. Loose boards should be nailed tight or replaced. Small openings should be caulked.

The tap-tap-tap of a woodpecker is a possible sign of food - bugs. An examination by a qualified pest control expert will ascertain if there is a problem that needs to be treated or if the woodpecker is just marking its territory. In both situations, the expert can install a device that will make the woodpecker fly on to a new location.

Bird droppings are a nuisance, at best. When pesky water fowl, especially Canadian geese, decide to take up residence in a yard, the problem becomes horrible. Until recently, there was little that could be done to effectively remove the problem fowl. Now, a yard can be professionally sprayed with a bird repellent that smells like grape bubble gum. The spray, made from ingredients found in Concord grapes, works by making the treated grass very distasteful. After a few days of trying to eat the very bitter grass, the birds move on.

MOLES

Speaking of ruining a nice lawn, another pest around the yard is the mole. They dig trails through the soil looking for food - grubs and worms. They do not eat bulbs, plant roots or grass. While being virtually blind, moles rely on their keen sense of hearing to lead them to their food as it wiggles its way through the soil.

The best ways to get rid of moles are either to eliminate their food source or to trap them. The sonic devices seen in ads do not work - if moles leave an area where such a device has been installed in the ground, it is because of a lack of food rather than a dislike of the noise. Trapping a mole requires patience, even for the best professionals.

RATS

As fall comes upon the Northwest, and the cold weather sets in, the rats in every neighborhood head for the warmer climate - inside homes. At the first sight, sign or sound of the vermin, homeowners should call for professional help.

There are three elements in ridding a home of rats: elimination of them, decontaminating the infested area, and excluding them from reentry.

Unless the homeowner has a cat with good mousing instincts, the principal methods of elimination are traps and poisoned bait. The bait is put into locked plastic or metal boxes that are designed so that other animals cannot go through the maze to reach the bait. Once consumed by the rat, the bait causes a thirst which the rat quenches with water from natural sources outside the home.

As rats leave a urine trail into and through a home for others to follow, it is important to eliminate the trail. Otherwise, it will remain for up to a year. In most cases, the areas where the rats were in the home should be decontaminated.

Finally, the points of entry must be effectively closed off. This is done last, rather than first, to assure that no rats are trapped within the home.

SQUIRRELS, RACCOONS AND POSSUMS

These animals find attics and crawl spaces to be ideal places to set up housekeeping. They will cause a homeowner grief until they are removed and barred reentry.

The best way to evict these critters is by trapping them. Professional pest controllers will use the proper bait (non-poisonous) to lure the animals into a cage. Then, the captured animals will be moved to new environments, at least 30 miles from the point of origin.

Once the unwanted visitors have been moved, steps must be taken to exclude the reentry by other animals. For an attic space, tree limbs should be cut back from the house - none should be near the roof. All vents should have proper screening. Any other openings should be secured. For a crawl space or beneath a porch, it is important to find the point(s) of entry and construct a permanent barrier.

Homeowners with unwanted household guests should call an expert promptly for advice or assistance. Each day that goes by without action increases the probability of additional pests, as well as the damage they do.