Tree Squirrel Damage Prevention and Control Methods

Identification | Biology | Damage ID | Management | Resources

Overview of Damage Prevention
and Control Methods

Habitat Modification

  • Remove bird feeders 
  • Cut down or trim trees back at least 6 feet from buildings 

Exclusion 

  • Install sheet metal bands on isolated trees to prevent damage to developing nuts  
  • Install chimney caps 
  • Close external openings to buildings; do not seal animals inside the home 
  • Plastic tubes on non-electrical service wires may prevent access to buildings  

Frightening Devices 

  • Strobe lights  

Repellents 

  • Naphthalene 
  • Ro-Pel® 
  • capsaicin  
  • polybutenes  

Toxicants 

  • None registered 

Shooting 

  • .177-caliber pellet guns 
  • .22-caliber rifles 
  • Shotguns with No. 6 shot 

Trapping 

  • 5- x 5- x 18-inch (minimum) cage or box traps  
  • Rat traps, tunnel traps, choker traps, or body-gripping-style traps depending on species 

Other Control Methods 

  • One-way doors  
  • Squirrels may be captured by hand using leather gloves, nets, and snake tongs 

Damage Prevention and
Control Methods

Squirrels are active year-round and can be controlled whenever they are causing damage. Care must be taken to avoid abandoning young during the period when young maybe present, which can be February through August, as some species may mate twice a year. 

In situations with longstanding conflicts with tree squirrels, it is wise to use a variety of cost-effective methods to control the damage. Squirrels cause economic losses to homeowners, nut growers, and forest managers but the extent of these losses is not well known.  

Squirrels occasionally chew on electrical wires associated with vehicles leading to replacement costs of $500 to $1,000. Squirrels caused 177 power outages (24% of all outages) in Lincoln, Nebraska, in 1980. Estimated annual costs were $61,005 (2010 prices) for repairs, public relations, and lost revenue. Squirrels caused 332 outages in Omaha, in 1985, costing at least $94,237 (2010 prices). After squirrel guards were installed over pole-mounted transformers in Lincoln in 1985, annual costs were reduced 78% to $10,290 (2010 prices). 

Habitat Modification 

Trim limbs and trees to 6 to 8 feet away from buildings to prevent squirrels from jumping onto roofs. Other plants, such as ivy, that allow access should be trimmed as well. In backyards where squirrels cause problems at bird feeders, consider providing an alternative source of food. Wire or nail an ear of corn to a tree or wooden fence post away from where the squirrels are causing problems. Bird feeders should be modified to prevent foraging by squirrels at the feeder itself and on the ground. In high-value crop situations, it may be beneficial to remove woods or other trees near orchards to block the “squirrel highway.”  

Exclusion 

Prevent squirrels from traveling on wires by installing 2-foot sections of lightweight 2- to 3-inch diameter plastic pipe. Slit the pipe lengthwise, spread it open, and place it over the wire. The pipe will rotate on the wire and cause traveling squirrels to tumble. Critter Guard® (Critterguard.org) has created a device to stop squirrels from crossing wires. NEVER install wire guards on or near electrical bearing lines. Only professional electricians and power company employees should handle power lines.   

Prevent squirrels from climbing isolated trees and power poles by encircling them with a 2-foot wide collar of metal 6 feet off the ground (Figure 6). Consult the local power company before installing anything on a power pole.  

Figure 6. A tree trunk wrapped with aluminum flashing to prevent squirrels from climbing. Photo by Stephen M. Vantassel. 
Figure 7. ½-inch plywood was gnawed by a gray squirrel trying to reach her young. Photo by Stephen M. Vantassel. 

Attach metal using encircling wires held together with springs to allow for growth of the tree. Close openings to attics and other parts of buildings but make sure not to trap squirrels inside (Figure 7). They may cause a great deal of damage in their efforts to chew out. 

Place newspaper in a hole to determine if squirrels are actively using it. Place traps inside as a precaution after openings are closed. 

A squirrel excluder can be improvised by mounting an 18-inch section of 4-inch plastic pipe over an opening. The pipe should point down at a 45° angle.  

When young are not of concern, 1-way doors can be an effective tool. Use spring-loaded 1-way doors in combination with a large (1-foot square minimum) apron around the hole to reduce chew-ins. Freezing rain can freeze the door shut or open. Some animals will fight to enter harder than others to gain access. Chew-ins may occur, so prepare customers for the possibility.  

Figure 8. One-way door installed. Note the hole (arrow) created by the squirrel in response. Photo by Stephen M. Vantassel. 

Flying and red squirrels are easier to exclude because they lack the jaw strength of larger squirrels. Effective squirrel eviction requires careful site evaluation. One-way doors work best when the structure is sound, as this reduces the likelihood that a squirrel will chew in elsewhere (Figure 8). Secure vents and chimneys before installing a 1-way door. 

Figure 9. A colony trap in a positive set over a fascia hole (not visible at far left) for grey squirrels. The bottom of the trap has ½- x ½-inch hardware cloth to prevent roof damage. Photo by Dave Schmidt. 

Some WCOs use 1-way doors in combination with traps to help finish the job more quickly, as it motivates squirrels to check out the traps. Some 1-way doors are attached to traps turning them into what is known as “positive trapping” (Figure 9).Close openings to buildings with heavy ½-inch wire mesh, aluminum flashing, or make other suitable repairs. Custom-designed wire-mesh fences topped with electrified wires may keep squirrels out of gardens or small orchards. 

Frightening Devices 

No frightening devices have been proven effective. Strobe lights show some promise.  

Repellents 

Naphthalene may temporarily discourage squirrels from entering attics and other enclosed spaces. Use of naphthalene in attics of occupied buildings is not recommended, however, because it can cause severe distress to people. Use of any commercial repellent may require certification for pesticide use.  

Ro-pel® is a taste repellent that can be applied to seeds, bulbs, flowers, trees, shrubs, poles, fences, siding, and outdoor furniture. Another taste repellent, capsaicin is registered for use on maple sap collecting equipment.  

Polybutenes are sticky materials that can be applied to buildings, railings, downspouts, and other areas to keep squirrels from climbing. Polybutenes can be messy. A pre-application of masking tape is recommended. These products are best used to stop gnawing damage. 

Toxicants 

No toxicants are registered for the control of tree squirrels. 

Shooting 

Where firearms are permitted, shooting is effective. A shotgun with No. 6 shot or a .22-caliber rifle is suitable. Pellet rifles (.177-caliber) are another option. Check with your state wildlife agency for regulations pertaining to the species in your area.  

Trapping 

Fox and gray squirrels are classified as game species in most states, so trapping permits may be required from your local state wildlife agency. Several rules apply for trapping tree squirrels. First, place traps near den holes or on travel routes. Do not rely on bait to overcome poor location of traps. Most traps will be located off the ground, so be sure they are secure. Use enough traps and the correct type of traps. For gray and fox squirrels, use at least 3 traps; for the smaller squirrels use 5 or more; use several more when trapping flying squirrels. Remove competing sources of food.  

Cage Traps 

Cage and box traps sized 5 x 5 x 18 inches or larger are effective in capturing tree squirrels. Use of cages made from ½- x 1-inch mesh will reduce the likelihood of damage to surrounding materials by trapped animals. Cage traps can be secured to trees and plywood shelves. In each case, be sure the squirrel has a 2- to 3-inch area to stand in front of the door. If legal in your state, multiple catch traps are extremely effective on flying squirrels, and can be used on other squirrels as well (Figure 9).  

Body-gripping Traps 

Body-gripping traps are very effective and show a low refusal (avoidance) rate, as they are quite inconspicuous. These traps are most commonly used in a positive set, in which the trap is set over the only entry available (Figures 10a and 10b). Tunnel traps (Figure 10c) offer an excellent way to catch squirrels as captures are almost completely out of public view. Drill small holes at the ends of the trap to enable you to secure the trap several ways.  

Figure 10a. A properly set body-gripping No. 55 set for gray squirrels. The hardware cloth on the trigger (middle of trap) prevents young squirrels from going through without being caught. Photo by Dave Schmidt.   
Figure 10b. Gray squirrel in a body-gripping trap.  
Photo by Dave Schmidt. 

Glue traps for rats will catch small squirrels, but this tool is not recommended. Effective bait for squirrels includes slices of orange and apple, walnuts or pecans removed from the shell, and peanut butter. Other foods, such as corn or oil-sunflower seeds that are familiar to the squirrel also may work well. Nuts rarely work as bait during fall when natural foods are available. Consider alternate baits if trapping in fall. 

Figure 10c. Two tunnel traps secured to a sheet of plywood to protect the roof.  
Photo by Stephen M. Vantassel.

Rat-sized snap traps are very effective on red and flying squirrels. Place them inside cubby boxes to force squirrels to approach the trigger only, or set them vertically on walls with bait side down. Use these traps indoors or where birds cannot access them (Figure 10d).  

Figure 10d. Red squirrel caught with a rat trap.  
Photo by Stephen M. Vantassel. 

Foothold Traps 

No. 0 or 1 foothold traps will catch squirrels but they are not recommended, due to risks to non-target animals and concerns about humanness.  

Handling 

Relocation 

In rescue situations such as from chimneys or basements, on-site release of squirrels is recommended, provided the entrance has been secured. 

Translocation 

Tree squirrels should not be translocated because of the stress placed on both transported and resident squirrels, and concerns regarding the transmission of diseases. Many states do not allow the translocation of squirrels. Check with your local wildlife agency.  

Euthanasia 

Carbon dioxide is the preferred method of euthanasia for tree squirrels. Squirrels expire relatively quickly in a rich carbon-dioxide environment.  

Disposal 

Check your state regulations regarding disposal of carcasses.  

Other Control Methods 

Squirrels in Chimneys and Basements 

During the mating season, it is not uncommon for males to search openings, looking for females. Unfortunately, many squirrels become trapped in chimneys, as they are unable to grip the smooth flue tiles. Removal of squirrels in chimneys is a special circumstance fraught with risk. The largest risk is being bitten when handling squirrels. In addition, there is a chance that a soot-covered squirrel will run around a pristine living room. Several different chimney types and situations exist, so we provide a few principles to help guide your work with squirrels in chimneys. Before opening a chimney damper, wear your personal protection equipment (PPE) including a hat or cap, safety glasses, a dust mask, and heavy gloves. 

A squirrel trapped in a chimney rarely will survive for more than 3 days. It is normal for the noise level to drop as a squirrel weakens. Try to remove squirrels before they die in a chimney. 

If possible, secure the opening of a fireplace, set a baited trap, and open the damper. Return the next day. Squirrels may be able to climb out if a 1-inch thick hemp rope is hung in the flue. Squirrels must be healthy enough to climb for this to be an effective technique. Use snake tongs to grab squirrels that are cornered and hand nets to catch loose squirrels. Before opening a damper, remove valuable and breakable items, and close doors in the vicinity. Squirrels will run to daylight, so try to make the lighted area lead to the outdoors.