Batty About Bat Regulations

The winter tree clearing season of October 1 through March 31 is coming to a close, but development projects won’t wait until the winter window comes around again. If a project had an unexpected schedule change or late start, tree clearing may need to come after the season ends.

The restrictions around tree clearing are intended to protect threatened and endangered bat species, such as Indiana (Myotis sodalis) and northern long-eared bat (M. septentrionalis), and must be followed by any entity developing a project with a federal connection, such as funding or permitting. Because these bat species hibernate in the winter and are not using the trees to roost, winter is the ideal time to clear trees. 

If a site meets various requirements, U.S. Fish and Wildlife Service (USFWS) and the state department of natural resources may grant permission to conduct a bat mist-net survey for Indiana and northern long-eared bats. The results of this survey will determine whether permission is granted to cut trees outside of the winter clearing season.

What is a bat mist-net survey?

Although there are a number of different survey types, the bat mist-net survey is the most common method used to get permission for summer tree clearing. The typical bat mist-net survey is done over multiple nights using black nylon mesh nets suspended between two poles to capture bats. Netting begins at sunset and continues for a minimum of five hours.

Any bats captured in the netting are identified to determine if they are endangered. Once the survey is complete, a report of the results is submitted to USFWS and the state department of natural resources for review. Assuming no Indiana or northern-long eared bats are captured, applicants are typically given permission to clear trees outside of the winter clearing season for the site surveyed.

The survey can only be conducted by a qualified biologist that holds a federal and state permit from USFWS and the state department of natural resources and can only take place between June 1 and August 15 under certain weather conditions. These conditions include no precipitation, temperatures greater than 50˚F, and wind speed still to calm. Approval to clear trees lasts for five years unless otherwise stated.

Contact your local Davey Resource Group representative to learn more about bats and tree clearing, and to find a solution if your project is affected.

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