Although the Indiana bat (Myotis sodalis) has been listed as an endangered species for many years, impact to this species was rarely raised during the review of permit applications in New York. That situation has changed recently and now both federal and state agencies frequently request that potential impacts to Indiana bats be addressed, especially if the project is located within 40 miles of a known hibernaculum. This heightened concern is due to a change in what we know about the spring and summer range of this species in New York.

     Indiana bats hibernate in limestone caves. They emerge from their winter hibernacula from mid-April through May. Recent research found that bats leaving New York caves travel 20 to 40 miles, to spring roosting sites.

     Roost trees are characterized by the presence of loose bark or narrow cracks and crevices that provide protection from the elements and predators. Mature shagbark hickory is one of the most commonly used trees because the "shaggy" bark offers perfect roosting conditions. Other tree species are used, especially if narrow gaps exist between the trunk and the bark. In the Hudson Valley Region, Indiana bats were found roosting under the bark of dead black locust trees. In central New York, where TES participated in a 2006 roost survey, a crack in a silver maple tree snag was used.

    The key question is how to determine whether a proposed project represents a threat to bat roosting habitat and, more importantly, is this a threat to the species? Unfortunately, there is no simple answer, no cookbook approach that results in a definitive conclusion.

     The first step is to assess the position of the site in the general landscape and determine whether or not appropriate forest conditions exist. Floodplains and riparian areas are preferred, especially if a forested wetland or wetland complex that includes large trees is present. Sites above 1,000 to 1,200 feet in elevation can be dismissed, because so far the research has located roosting females only at lower elevations.

     If cutting trees for a project development will occur, the next step is to determine the potential suitability of those trees. Species, size, and condition are the key elements to be considered. Determining the presence or absence of large shagbark hickory trees is the easy part. But other trees with exfoliating bark might represent a potential roosting site. Lastly, determining if any tree, large or small, has a narrow crack or split in the trunk is the most difficult aspect of the assessment. Such trees can be living or dead, and the crack might occur where visibility is limited.

     Keep in mind the fact that Indiana bat roosting habitat may be an issue of concern only when a federal permit is needed, although it could be raised during a SEQR review. If no federal permit is required, or if no trees will be disturbed, then one need not worry about this potential issue.

     Some developers have identified the mere question of Indiana bat habitat as a serious impediment to development, not only because of increased regulatory complexity, but because local citizens groups and even some competitors have seized upon this issue to delay proposed projects.

     The regulatory agencies face a very delicate problem regarding Indiana bats. The Endangered Species Act prohibits the harming or killing (i.e. "taking") of a listed species or affecting designated critical habitat. Cutting trees during the fall or winter months can be done without harming any bats. If a point is reached where developers consider dealing with this issue within the regulatory process to be too burdensome, the ultimate impact on Indiana bat habitat could be far greater than it was without regulatory oversight.