What animal is living in my attic?

The quickest clue is when you hear it. Light scurrying at night usually means flying squirrels, rats or mice. Heavy thumps at night suggest a raccoon. Noise at dawn and late afternoon fits gray squirrels. Small animals leaving the roofline at dusk are most likely bats. The size of the way in, the droppings and the damage narrow it down from there, and a licensed wildlife pro can confirm before anything is sealed.

Start with when you hear it

Write down the times for a few days. It is the most useful thing you can tell a wildlife company.

At night. The Virginia Department of Wildlife Resources names flying squirrels as the most common culprits in attics, and they are nocturnal.^[1] Rats and mice can sound much the same, so the droppings and damage below help tell them apart. Raccoons are nocturnal and primarily active at night.^[3]

Early morning and late afternoon. Fairfax County says squirrels are diurnal, with peak activity at dawn and late afternoon.^[2] A noise that starts around sunrise, goes quiet midday and picks up again before dark is a classic gray squirrel pattern.

At dusk, outside. Bats are quiet in the attic but easy to see leaving. DWR's advice for finding them is watching the outside of the house from dusk until about a half-hour after sunset to see where bats leave as they go out to feed.^[5]

How heavy it sounds

Size changes the sound. A raccoon is 2.5 to 4 feet long, nose to tail, and weighs 10 to 30 pounds, while a gray squirrel weighs 1 to 1.5 pounds.^[3][2] Heavy walking, thumping and dragging overhead usually means a raccoon. Quick, light scratching and rolling sounds, like a nut across the floor, usually mean squirrels or rodents. Chirping or squeaking from one spot in spring can mean a nest of young; squirrels have 1 to 2 litters a year with 2 to 4 young per litter.^[2]

Raccoons do not need an attic, and raccoons are usually drawn by food or an easy place to den, such as under porches and decks, in crawl spaces or in outbuildings.^[4] When one is in the attic, there is often visible damage at the roofline where it got in.

The size of the way in

From the ground, look at soffits, gable vents, roof edges, the chimney and any place where a pipe or wire enters the house. Binoculars help. Do not climb onto the roof to look.

Small openings point to small animals. Holes chewed through walls and floors are one of the signs the Environmental Protection Agency lists for rats and mice.^[6] The Norway rat, the roof rat and the house mouse, all non-native, are among the rodents that become pests when they infest houses.^[7]

A round hole with chewed edges, often at a corner of the roofline or beside a vent, usually means squirrels. Torn vent covers, lifted shingles or a pulled-back soffit panel usually point to a raccoon. Narrow gaps along the roofline with dark staining around them often point to bats.

What they leave behind

Bats have particular habits worth knowing. The big brown bat, evening bat, little brown bat and Brazilian free-tailed bat are the four Virginia species most likely to take up residence in a building.^[5] From May through August, bats may have young still present in the space they use.^[5] A pile of small dark droppings building up under one spot is a common sign of a roost.

Rodents leave a trail. EPA lists the signs to look for: droppings, nesting material such as shredded paper, fabric or dried plant matter, signs of chewing, and stale smells coming from hidden areas.^[6] Rodent-borne diseases can reach people through bites and through food, water or dust contaminated by rodent droppings and other waste.^[7]

Look from the attic hatch rather than crawling through. Bat droppings can harbor the spores of the fungus that causes histoplasmosis, and DWR says a large buildup should be cleaned up by a professional.^[5] The Virginia Department of Health says the fungus grows best in soil that contains bird or bat droppings, and its spores get into the air if contaminated soil is disturbed and are then breathed in.^[9]

Signs to act on now

Some findings should not wait:

• Chewed wiring. Have an electrician look at any wiring an animal has chewed before anyone works around it.
• A bat in the living space. The Virginia Department of Health says if you wake up to find a bat in your room, or see one in the room of an unattended child, do not destroy or discard the bat, and call your local health department for advice.^[8]
• An animal that looks sick. Seeing a raccoon during the day is not by itself a sign of rabies, but the Department of Wildlife Resources says to contact your local health department if one shows signs such as stumbling, foaming at the mouth or aggression.^[4]
• Water stains or daylight at the roof deck where an animal got in, which can mean a roof leak as well.

Do not seal the hole yet. If an animal or a litter is still inside, sealing traps it or sends the mother tearing back in somewhere else.

When to call a licensed pro

Call a permitted wildlife control operator once you have a likely suspect, or sooner if you see any of the signs above. DWR's Trapper Finder Tool lists licensed trappers and Commercial Nuisance Animal Permit holders near you and the species each is willing to trap.^[10] Tell the company what you heard and when, and where you saw the entry. For what happens next, read how wildlife removal companies get animals out of an attic and what wildlife removal costs in Virginia.

The repairs afterwards are building work. Virginia's definition of a contractor covers repair or improvement of a building, including cleanup of contaminants, and a Class C licence covers single jobs over $1,000 but less than $30,000.^[11] Check any licence with how to check if a contractor is licensed in Virginia. Browse wildlife removal businesses, find pest control businesses in Blacksburg, or read more pest control answers.

Tell us what you are hearing and when and local wildlife control businesses can quote an inspection.