Wildlife and Heritage Service Policy Paper
Wildlife Control Cooperators and Nuisance Bats
20 October 2004

1. Pesticide applicators must follow DNR guidelines for bat exclusions.

All companies that do nuisance bat work in the state of Maryland must have a wildlife control cooperators permit from the Maryland Department of Natural Resources, including pesticide applicators that are licensed by the Maryland Department of Agriculture and national pesticide companies with offices in Maryland. Each branch office of a single company must be licensed individually. Pesticide applicators who are found to be in violation of their pesticide applicator’s license by fogging bat colonies that are in the building, applying chemicals, or otherwise improperly excluding bats will be reported to DNR police and the Maryland Department of Agriculture. These actions may result in revocation of the wildlife control cooperators permit.

2. Cooperators wanting to do bat work must inform DNR and demonstrate proper knowledge of bat exclusion techniques.

Only non-lethal methods may be used for the removal of nuisance bats by wildlife control cooperators. Cooperators who wish to do bat work must indicate “bats” specifically on their permit form and not small mammals. Only those cooperators who list bats will be listed on DNR’s bat web page at http://www.dnr.state.md.us/wildlife/bats/nhpbatintro.asp and referred to customers by DNR. Cooperators are strongly advised to become familiar with information on DNR’s bat exclusion policy and refer customers to the web site whenever possible. Wildlife cooperators who build and install bat boxes will also be listed on the web site.

3. A single bat found within the living quarters may be removed without DNR approval regardless of the time of year.

A single bat found within the living quarters or working space (e.g. bedroom, living room, kitchen, hallway, office) may be captured and released at any time of the year without prior approval from the Maryland Department of Natural Resources. The cooperator should make an effort to find out how the bat got inside the living quarters or working space and whether or not a colony is present. If the bat was found in the living quarters or working space during March 1-August 31, the cooperator should immediately examine the building for potential colonies and temporarily or permanently seal ways of entrance into the living quarters or working space from non-living quarters. If the cooperator finds or suspects that a colony exists in any non-living quarters (e.g. the attic, roof, soffet, walls, etc.) then the cooperator must diagnose the situation further and determine the main entrance holes and potential future access holes. An exit count of the colony at dusk is helpful and can be done by the cooperator or the owner of the house. Potential access holes can be sealed leaving the main exits open until September 1.

4. Health department officials should be contacted immediately if a person is bitten by a bat.

Health Department officials may authorize the submission of individual bats for rabies testing if that bat has bitten an individual person, or if exposure to the animal cannot be ruled out (i.e. exposure involving young children that cannot talk, mentally-impaired individuals, etc.). Only humane methods of euthanasia can be used for securing the specimen for rabies testing. Bats submitted for testing should be identified to species if possible. A key to bat identification is available on the web site.

5. Bat colonies may not be excluded from buildings from March 1 to August 31.

Non-lethal exclusion is the only method permitted by the Maryland Department of Natural Resources for nuisance bat colonies. Exclusion of colonies must take place after August 31 but before bats begin hibernation. Once the bats have left or have been successfully excluded, sealing of the main entrance is required and must be completed. Repellents are not effective and are not long-term solutions to nuisance bat situations, including pesticides used to treat insect pests while bats are still present in the colony. Information on exclusion techniques is available on DNR’s bat web page: www.dnr.state.md.us/wildlife/bats/batsinhome.asp.

6. If the customer is reluctant to wait until September 1 for exclusion, the cooperator should survey the roost, outline work to the customer that can be done prior to September 1, and then direct the customer to call DNR with the survey results. The customer should never be told that nothing can be done until September 1.

If the colony is visible, the cooperator must survey the roost and report the stage of development of the young (fur present or absent, relative size of pup to female) to the Department of Natural Resources. Bats may give birth anytime between April through June. Colonies may be excluded prior to September 1 only with prior written approval from the Department of Natural Resources Wildlife and Heritage Service and only for the following reasons: 1) dates when young should be flying have been determined by the Department and permission has been granted to exclude after that time period, 2) pups are not present in the roost, 3) extenuating circumstances warrant exclusion before September 1. Homeowners must request an exception letter (not a permit) by calling Dana Limpert at 410-827-8612x108. No letter is needed if the exclusion occurs after September 1.Once the main exits have been identified, sealing of other possible entrances may and should occur prior to exclusion. There is always work that can be done in preparation for the exclusion. This tact is ultimately more satisfying for the customer and the one DNR recommends for cooperators.

7. Cooperators should always present factual information on bats, particularly related to health issues such as rabies and histoplasmosis.

For customer service purposes, the cooperator must take the time to allay the customer’s fear of bats if necessary. Cooperators must be knowledgeable in answering a customer’s questions about bats and diseases or bat behavior. The DNR bat web page should be consulted if necessary for information on rabies and histoplasmosis. Excluding bats at the wrong time of year can lead to far greater problems for the homeowner than the one he or she currently faces such as bats dying and creating an odor problem or more bats getting inside the living quarters. Female bats that have been excluded and have flightless young trapped inside the house will fly around the outside of the house and try to find another way to get to their pups. This situation increases the likelihood that the bats may come in contact with people.

8. Cooperators need to file an annual report on bat colony exclusion activity.

Cooperators must include the following information in an annual report to the Department: date, street address, city, zipcode, species, estimate of colony size, and work performed.

9. DNR reserves the right to revoke a cooperators permit to do bat exclusion if the cooperator fails to follow DNR bat exclusion policy as stated above.


For more information, please contact:
Maryland Department of Natural Resources
Wildlife and Heritage Service
Tawes State Office Building, E-1
Annapolis MD 21401
410-260-8540
Toll-free in Maryland: 1-877-620-8DNR, Ext. 8540