Critter Proofing Your Home

Critter Proofing Your Home

Discovering unwanted wildlife in your home can be unsettling, but with proactive measures and humane eviction methods, you can safeguard your property effectively. Whether it’s critter-proofing your home or evicting unwanted guests from your attic, here’s a comprehensive guide:

Be proactive

Conduct a yearly examination of your home. Check for potential problem areas such as small holes through which animals can gain access to your attic or a chimney cap that needs replacing. Make all repairs early in the year, before pregnant females begin seeking nesting sites.

Handling Specific Wildlife Situations

Bird nest in attic louver

Check bird nests in attic louvers for babies. If present, monitor weekly until vacated (usually 2–3 weeks). Clean out debris and screen the entire vent with ½-inch mesh hardware cloth.

Animals in the Attic

  • Inspect Your Attic: Check for animals , particularly in spring and early summer which is when babies are most likely to be found. If present, the best option is to allow them to grow big enough to leave on their own, which will be 6–7 weeks, depending on the species. If adults only are present, use mild harassment (see Make Your Attic Unwelcoming below). Once the animals are gone, repair the entry point immediately (see Seal Entry Points below).
  • Identify the Species: First and foremost, determine what type of animal is living in your attic. Locate the entry points they are using to get in and out. During daylight hours, inspect your attic for areas where light is coming in. These spots indicate potential entry points. In the evening, observe these spots from outside to see the animals’ behavior. Raccoons typically leave at dusk, while squirrels return home around that time, and bats emerge in a steady stream at dusk.
  • Make Your Attic Unwelcoming: If you cannot wait for the wildlife to leave on its own, you can encourage them to vacate. Animals seek warm, safe, dark, and quiet places for their young. To encourage them to relocate, make your attic the opposite. Use attic fans or additional fans, turn on lights, and use battery-operated stick-on lights to illuminate the space brightly. Play loud music or talk radio throughout the day to create noise. The goal is to make the attic uncomfortable and uninhabitable for the animals.
  • Allow the Mother to Leave: After implementing deterrents, give the mother animal time to leave the attic with her young. This step is crucial to prevent damage to your property. If you’re certain the mother has vacated, you can carefully place the babies in a box outside, wrapped in towels, to reunite them with their mother. Alternatively, observe from a distance as the mother retrieves her young. Avoid interfering as she makes multiple trips to relocate her offspring.
  • Seal Entry Points: Once the mother and babies have left, seal all potential entry points into your attic, except for one. Leave this last entry point open, but plug it loosely with newspaper or tissue to ensure all babies have been removed. If the paper remains undisturbed after 48 hours and no cries are heard from the attic, it’s safe to seal the remaining entry points completely. This prevents future wildlife from entering your attic.
  • Special Note: Bats in the Attic: The only effective way to prevent bats from entering attics is to seal any gap greater than 1/2 inch and check the attic screening every winter. In addition to preventing bats from entering your attic, it helps you save money by saving energy. If bats are discovered, wait to exclude them until the young are able to fly, which will be by September 1st; otherwise desperate mothers will try to reunite with their young through any opening, meaning they are very likely to enter your living spaces. In addition, the young will starve to death and decompose in the attic, resulting in smells, stains and days of piteous crying.

Wildlife In The Chimney

  • Raccoons: Using a flashlight check the chimney for babies, particularly in the spring and early summer. If present, allow them to grow big enough to leave, usually in 6–7 weeks. If you can hear them “chattering” in the chimney, they are probably already 2–3 weeks old. Do NOT set a fire in the fireplace; the babies cannot get out and will be burned. Adult raccoons will leave every night at dusk. Once all animals are gone, install a chimney cap.
  • Chimney swifts: Often referred to as “cigars with wings,” Chimney Swifts are remarkable birds that spend most of their lives in flight, feasting on insects. They migrate to North America in the spring to nest, often within chimneys. If you find fallen nestlings or fledglings in your fireplace, it’s crucial to act swiftly. By placing them back in the chimney, preferably on the smoke shelf above the damper, you give them the chance to be reunited with their parents and complete their development. Close the flue and seal any gaps to prevent them from falling back into the fireplace. Unfortunately, the chimney swift population has been declining due to factors such as habitat loss and reduced insect populations, making it more important than ever to protect and assist these fascinating birds.

Bird Nest in Dryer or Stove Exhaust Vents

These are usually English sparrows or starlings.They raise young year-round but typically are active from early spring through early fall. When the young have vacated the nest, which will be in 2–3 weeks (and before the next clutch is laid), clean out debris. A vacuum cleaner hose is helpful. Cover vent opening with hardware cloth. If you must remove the nest for safety reasons, renest close to the vent outlet and watch to see if the parents come back to care for the young.

Mice Entering Garage Under Door

Mice can enter ¼-inch gaps. Check doors for weather stripping. If chewed through, wrap metal flashing around the bottom edge of the door. Caulk and fill in any cracks around the foundation of the house. Do not use glue traps; they might catch a few mice but they are inhumane and do not solve the underlying problem. They also catch other, innocent animals such as birds and bats. If you must, you can purchase humane mouse traps, and release caught mice away from your home.

Wildlife Eating Pet Food

Do not feed pets outside, or if absolutely necessary, leave food out only during daylight hours. Pet food WILL attract wildlife.

Groundhogs Burrowing Under Concrete Slab, Deck, Porch, Etc.

Do not attempt to evict groundhogs during winter months as they are true hibernators, or during the spring to mid-summer when there are babies. At other times, use mild harassment techniques such as mylar windmills planted around the yard or a beach ball that will move with the wind around the yard. Groundhogs are cautious animals that are easily frightened, and have poor eyesight. When you are sure the animal is gone, dig a trench along the slab 1 ½ feet wide and 1 ½ feet deep. Fold an appropriate length of 3-foot wide hardware cloth into an “L” shape and bury in the trench. Tamp soil firmly and cover with a 1-inch layer of gravel, 6 inches wide and 6 inches deep.

Snake Entering Basement Around Duct or Dryer Vent

Caulk around all pipes, vents and ductwork that lead from outside to inside the house. Fill large gaps with steel wool before caulking.

General Housekeeping

Keep shrubs and tree branches trimmed at least 1 foot away from the house or roof. Keep grass cut short. Check window screens for tears. Check attic vents for screens. Screen exhaust fans with hardware cloth. Check concrete patios and porches for signs of soil erosion away from the side and fill any gaps with 1-inch gravel if necessary.

By following these steps, you can effectively critter-proof your home and evict unwanted wildlife from your attic without causing harm to the animals or your property. Remember to prioritize the safety and well-being of both the animals and yourself throughout the process.


  • Wildlife Rescue League Hotline Manual, 2003
  • Wild Neighbors, The Humane Approach to Living with Wildlife, by John Hadidian, 2007
  • Healers of the Wild, by Shannon Jacobs, 1998
  • Humane Indiana Wildlife Facebook page, 2024
  • Wildlife Rescue League Nutley News, August 2023

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Wildlife Rescue League - Viriginia
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