Our goal is to promote exclusion methods that ensure the safety of both bats and people. We understand that differing architectural structure and/or climatic conditions may require modification of the guidelines given below.

As a BCI approved exclusion professional, University uses only approved exclusion methods. We provide the property owner with a guarantee and list of references.

One-way devices called excluders are the preferred methods for evicting bats from buildings. Excluders should be placed at all active entry points and should remain in place for at least 5 to 7 days. These devices should be removed after the bats have been excluded, and then exclusion points should be sealed with silicone caulking, caulk backing rod, hardware cloth, or heavy duty polypropylene mesh. In some cases, sealing may require repair or replacement of old, deteriorated wood. University strongly recommends that spot treatments be avoided and that entire buildings are excluded from further bat activity. Moving bats from one corner of a building to another does not solve the problem and may require that further exclusion work is carried out at some time in the future, further disturbing the bats and the property owner.

Please note that simply waiting until the bats have flown out at night and then permanently sealing entrances shut without the use of exclusion devices, is not advisable and may in fact be a violation of protected species acts. This method often traps some bats inside the building. University also discourages the use of 'permanent netting' in most situations.

Extreme caution should be exercised when considering aerosol dog and cat repellents. They may discourage bat use of a particular roosting spot for periods of up to several months and have been used effectively to prevent bats from night-roosting above porches. But can cause harm to bats if they come into direct contact with these sprays. The spray should be applied by day when bats are not present. Aerosol repellents are not an adequate substitute for exclusion in the case of day roosts and should never be applied when bats are in a roost. For night roosts, we also recommend the use of Mylar balloons or strips of tin foil hung from roosting areas and allowed to move in the breeze.

Maternity season for bats in the US and Canada can range from 1 May through 31 August, although pups have been seen as early as late April in some instances. Eviction of bats, or any activity that directly affects their roosting area, should occur only prior to or after the maternity season, when young will not be trapped inside, creating additional problems.

Some bats hibernate in buildings during the winter months. Winter exclusions should be performed only if it can be determined that no bats are hibernating in the building. If bats are present during the winter months, exclusions should be postponed until spring temperatures are warm enough for deciduous plants to leaf out and insects to again be abundant.

Ultrasonic devices, chemical repellents, and smoke are not effective methods to evict bats from buildings. In addition, canned spray foam is not an approved sealant for cracks and holes in most situations. It is not only unattractive, but can result in the death of bats that come into contact with it. This product should never be used when bats are still present.

Traps and relocation are not approved exclusion techniques. Removing large numbers of bats from a building may seem impressive to a customer, but is unlikely to be effective. Traps can be fatal to bats if left unattended or if overcrowding occurs. Bats have excellent homing instincts making relocation attempts unlikely to succeed. They will simply attempt to return to the original capture area upon release. Capturing bats at an exclusion site is not encouraged, although capturing a single bat for species ID or removal of an individual bat from a living space are exceptions to this rule.