Fixits: Oh, rats: They hear noises in the attic

Q Is it possible to have rats in the attic and nowhere else in the house? We've had mice before and they often showed themselves. Years ago, we heard scratching above our bed and the exterminator told us there were rat droppings. He killed them off, but now we're hearing the same noises. They come and get the poison we put out and then a few weeks later we hear them again. Are they dying off and new ones coming? I'm scared to death that they'll start making their way into other areas of our house.

A Yes, you can have rats in the attic and not elsewhere. But you're probably writing from a southern climate. Rats aren't a problem in Minnesota attics.

You're likely dealing with roof rats, a species different from the Norway rat we have in Minnesota. The roof rat is more aerial and an attic problem in coastal states and along the Pacific Coast. The Norway rat prefers lower levels of a building, but it's a good climber and will go where there's a food supply.

Rats, unlike mice, aren't often seen, but they leave evidence in the form of droppings and smudge marks as oil and dirt rub off their fur as they travel along. Roof rats will leave marks high on rafters while other rats and mice leave them lower on walls, along the floor.

In any case, traps are a better solution for rat infestation than poison. With poison, you run the risk of the rat dying in a wall cavity or other inaccessible area. The odor can be overwhelming and may last a long time.

Call another pest control company to verify that your problem is rats. (It may simply be mice.) Remember that vermin control is a three-pronged approach: elimination, exclusion and sanitation. Eliminate food supplies by keeping garbage, birdseed and pet food in rodent-proof containers. Go around your house and attic, carefully sealing and closing up any openings. Keep bushes and trees pruned away from the house, clean up debris and keep firewood stacks away from walls.

Source: Includes information from the University of Arizona Extension Service Send your questions to Fixit in care of the Star Tribune, 425 Portland Av. S., Minneapolis, MN 55488, or call 612-673-7032, or e-mail fixit@ startribune.com. Past columns are available at www.startribune.com/fixit. Sorry, Fixit cannot supply individual replies.