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Wildlife in the Attic or Eaves

Situation: You have an animal living in the attic, walls or the eaves of your home or business. The Wildlife Rehabiliation Center at the Wisconsin Humane Society can help! Follow the tips below for safe and humane ways of removing or coexisting with wildlife in your life.

Why This Happens: Wild animals survive by constantly searching for and utilizing the resources they find in their environment.  They interpret a loose or missing fascia board on your home’s overhang or a hole caused by water damage in the side of your house as a “Welcome” sign.  They are not aware that they are trespassing; they only know that there is an entry hole that lets them get into a relatively warm, dark, safe and quiet place; out of the elements and safe from potential predators.

  • Animals like Gray Squirrels and Raccoons usually gain access through holes in loose, missing, or rotten soffit, fascia, or roof boards.  If these areas are not already rotted through, they may scratch or gnaw the rest of the way through -- this rot is often the result of previous water or ice damage. 
  • Animals also enter through attic vents of various types.  Squirrels may gnaw through wooden vent covers, and raccoons may tear open the vent cover to get inside.
  • Trees with trunks or branches that are close (within 6-10 feet) to your structure often serve as a ready means of access for these animals to climb up to your attic or eaves.  Or, an animal may climb up a downspout or a brick wall or chimney to get access to vulnerable parts of your home.

FAQs and Humane Solutions

“I have an animal in my attic. Will you come out here and remove it, or can I rent a live-trap from you so I can trap it myself?”

The answer to both questions is “no,” because we have a much better solution to offer: experience with thousands of such situations over more than 30 years has shown us that the self-help techniques we describe below are much more humane than trapping and relocating an animal, provide a more ecologically-sound solution than relocation, and are more likely to provide you with a lasting solution at far less expense than removal/relocation. For more information about our position on relocating wild animals, please click here.

“I have an animal in my attic. What can I do to get it to leave?”

Hazing - You can do what we call “hazing” to get the animal to leave.  Hazing involves temporarily converting that dark, safe, quiet wildlife haven inside your attic or eaves into a bright, noisy, smelly area in which the animal no longer feels comfortable or safe.  The supplies that will be needed are: a bright light such as a mechanic's trouble light or a floodlight, a portable radio, and some type of non-toxic animal repellent such as Critter Ridder, available through Wally’s Workbench here at the shelter or on our web site; or rags drenched in household ammonia.

IMPORTANT: In cases where there may be baby animals present, we recommend that if at all possible, you wait until the young are old enough to leave the nesting area before you start hazing.  There is a small chance that the hazing could get a mother animal to abandon her young or mistakenly not take all of her young when she moves out.  And birds cannot move their eggs or young to a new location, so you should not use hazing techniques on birds during their nesting season. Use of hazing techniques may cause a parent bird(s) to abandon nestlings, which is inhumane and in the case of native migratory birds, may be against state and federal laws. In southern Wisconsin, Gray Squirrels may have young as early as March and as late as September.  Raccoons may have young as early as April and as late as September.

Hazing Technique - Set up the light inside the structure, ideally about five feet away from the entrance hole, and turn it on, shining toward the entrance. Caution: keep power cords away from the entrance itself or the animal may gnaw on the cord! Make sure the light cannot tip over and that it is not hot enough or close enough to anything flammable that it could start a fire! If possible, place the radio within several feet of the animal's “den” or about five feet away from the entrance hole. Tune the radio to a talk station or a rock-and-roll station and have it on a moderately-loud volume. If possible, place rags drenched in household ammonia just inside the animal’s entrance hole or sprinkle the Critter Ridder just inside the entrance hole.  The animal might leave the first night you do this, but you’ll probably need to keep this up for three days in a row, or perhaps longer.  You can turn the radio off or turn the volume down periodically if the noise gets to be too much for you or your neighbors.  The ammonia on the rags will evaporate, so you’ll need to re-wet them with fresh ammonia once or twice a day.

Note: hazing works best in relatively small areas such as the attic of a small house.  In a very large area, such as the attic of an apartment building, the animal may simply avoid the hazing techniques by moving its activity away from the hazing to another part of the attic.  In this case, you’ll need to introduce enough light and noise to make the entire area uninhabitable.

“Once I have done the hazing, how do I know if the animal is gone?”

  • To determine if the animal is gone, loosely crumple newspaper into a ball and place it in the animal’s entry hole into the attic or eave.  If the newspaper is not disturbed after three days, the animal MAY have moved out.  However, this method is only reliable if there is no other place that the animal can get into the attic or eave.
  • Another option for checking to see if the animal has left is a “trail camera.”  These highly weather-resistant digital cameras automatically take a photo(s) or a clip of digital video when something passes in front of the camera.  These cameras are sold at sporting goods stores and online.  The camera should be placed so that the “shutter” will be triggered by an animal going in or out of the opening in the structure.  

“Once the animal has left, how can I prevent it or another animal from getting back inside?”

You are right, once this animal leaves and the hazing stops, if you don’t “animal-proof” the area you are very likely to have another animal eventually move in.  By “animal-proofing,” we mean installing a barrier that animals cannot chew through, pull apart, dig under, or climb over.  Welded wire mesh, hardware cloth, or chicken wire are usually good choices for this, since they are strong, long-lasting, easy to work with, are relatively inexpensive and, except for welded wire mesh, are readily available at most hardware stores and home improvement centers.  Welded wire mesh can be a little more challenging to find, but it is available from some farm and ranch supply stores, fencing retailers, and online.  If you are shopping for welded wire mesh, look for 1” x 1” or 1” x ½” galvanized mesh made with 16 gauge wire.

Materials you will need:

  • Galvanized hardware cloth, or welded wire mesh, or chicken wire
  • Screws – we like 1 ¼” galvanized pan-head lath screws, but deck screws should also work
  • Fender washers – we like 1” diameter washers with a 3/16” hole

Tools you will need:

  • Safety glasses
  • Leather gloves – to protect your hands from possibly sharp metal edges
  • Cordless or corded drill/screwdriver with appropriate bit for driving the screws you will be using
  • Wire cutter, or sheet metal cutting shears (the latter works well for hardware cloth)
  • Optional – for large jobs, you may want to rent an electric sheet-metal and wire-mesh cutting shears.  Or for cutting welded wire mesh, use an electric reciprocating saw with a metal-cutting blade to speed-up the mesh-cutting process.

Instructions:

1) Cut the mesh to fit.  Measure the width and length of the piece(s) of mesh you’ll need.  Make the piece of mesh a few inches in each direction larger than the hole.  Cut the piece and fit it into place.  Trim and/or bend the piece as needed until it fits properly. 

2) Install the wire mesh.  Use the drill/driver to install the mesh to the structure over the hole or the repaired area using the lath screws and fender washers.  To do this, hold the mesh in place and drive the screw through a washer and the mesh to anchor the mesh to the structure.  Use as many screws and washers as are needed to securely hold the mesh in place.    

3) Animal-proof other possible entry points.  With the entry hole gone, animals may look for other weak points on your structure that they can use to get inside.  These weak points are often areas of water-damaged or rotted wood, loose trim boards or siding, and flimsy or missing vent covers.  Proactively install wire mesh over these areas to keep animals from gnawing through or tearing open these weakened spots.  Pay careful attention to corners – anywhere that two walls or panels meet -- such as under overhangs, outside corners of the fascia, where gables meet the roofline, etc.

4). After you’ve repaired and animal-proofed your garage or shed, check back at least twice a day for the next three days to make sure that no animals have accidentally been closed inside and are unable to get out!  If an animal appears to be desperately and persistently trying to get back in the structure, it may be a mother animal with babies still inside.  In this case, temporarily remove the mesh you installed over the entrance hole.  Not being able to get to her babies for a short time is often enough to get a mom animal to move her young elsewhere.  Resume the hazing techniques and give her another day or two to move her family out. 

“How can I prevent animals from climbing on my roof and getting into my attic or eaves?”

  • Trim trees and branches so that they are at least six, but preferably 10, feet away from your home.  Raccoons are not good jumpers, but squirrels can jump several feet to get on and off of your structure.
  • If a tree can’t be cut down or pruned-back, you can wrap the trunk of the tree with two-foot-wide galvanized sheet metal and attach it to the tree with nails or screws.  If properly installed, the sheet metal is too slippery and too wide for climbing animals (like squirrels and raccoons) to get past.  The bottom of the sheet metal should be six feet or more above the ground so squirrels can’t jump over the sheet metal.

Important: Don’t trim branches or trunk-wrap a tree with sheet metal during the nesting season, which for some animals, like Gray Squirrels, can run from April through September, unless you are sure there are no baby animals inside your home! Trimming branches could prevent a mother animal from getting back to and caring for her young.  Of course, this would be inhumane and could result in the deaths of the babies, leaving you with the unpleasantness of having dead animals in your attic or eaves.

“I’ve heard that a one-way door can be used to let an animal living in an attic, eave, or wall get out but not get back in. Can I use this to get the squirrels out of my attic?”

One-way doors, especially when put in place a couple of days after hazing techniques (see above) have begun, can be helpful.  But one must be very careful when using these devices to make sure that a mother animal is not prevented from getting to her babies.  And if installed without concurrently using hazing techniques and proactively applying animal-proofing on other vulnerable areas of the structure, can lead to an animal getting back into the structure through a different weak spot.

Products & Solutions

Welded-wire mesh installed over a massive hole caused by water-damage to a homes’ eave.  A raccoon had been using the hole to get in and out of the attic. After the wood is repaired, the mesh can be temporarily re-installed over the repair to make sure animals don’t try to get back in that way.


 

Wire-mesh installed over a repaired plumbing mat around a roof vent pipe.  A raccoon had torn up the shingles and the plumbing mat to get into the attic.  The mat is installed with lath screws and fender washers.  The screws are daubed with waterproofing caulk.  Note the “cap” of wire mesh on the pipe to exclude small birds and squirrels.


 

An “L”-shaped strip of welded-wire mesh installed around a roof vent to keep out raccoons and squirrels.  The mesh is attached with lath screws and fender washers.  The screws in the roof itself are daubed with rubberized asphalt roofing caulk for waterproofing.


 

A welded-wire mesh “box” and a one-way door installed over an attic vent pulled off by a raccoon to gain entry to an attic.  The one-way door will be removed once it is certain that the raccoon has left the attic.  Note the mesh installed on the vent in the background as a precaution.


 

A band of sheet metal, at least 2-feet, but preferably 3-feet wide, nailed or screwed to a tree trunk a few feet above the ground can help keep raccoons and squirrels from climbing a tree that grows very close to a house


 

Exclusionary mesh and a one-way door installed around a raccoon entry under the overhang where the roof of a gable meets the main roof – a favored spot for wildlife entry into attics.


 

Critter Ridder is a non-toxic, pepper-based, granular animal repellent that may help when hazing a raccoon or squirrel.  This product is available here at the shelter or on our web site.


 

Strips of “porcupine wires” attached to the overhang, downspout, and/or outside corners of walls can help prevent raccoons from climbing these areas to get to the eaves and roof. These should be installed at least 9-feet above the ground to prevent accidental contact with the sharp wires by people.  These are most effective when used BEFORE you have a problem with an animal getting into your attic or eaves.  These wires are available online.