New York Natural Heritage Program
Eastern Red Bat
Lasiurus borealis (Muller, 1776)

Conservation Overview [-]
Eastern red bats are regularly encountered in New York and may occur in a variety of habitats and sometimes in proximity to moderate human densities. They are killed during collisions with wind turbines during the late-summer/early-fall migration period and it is not yet known whether this is a threat to the persistence of healthy populations in New York.

Threats [-]
Red bats are migratory tree bats that migrate rather than congregate in caves over the winter, and are not known to be affected by white-nose syndrome which has devastated cave bat populations in eastern North America. The incidence of rabies in eastern red bats is moderate to high and may be of concern in some regions. Studies report the incidence of rabies among submitted carcasses as 11% in Indiana (Whitaker and Douglas 2006) and 5% in New York (Childs et al. 1994).
Red bats are killed when they collide with wind turbines in New York, particularly during fall migration. It is unknown whether the numbers of bats killed at turbines during migration is high enough to impact population numbers in the state. One study reported that red bats made up to 61% of bat carcasses found at wind facilities in the eastern U.S (Arnett et al. 2008).
Bats may be particularly sensitive to environmental toxins including those found in herbicides and pesticides. They are highly susceptible to DDT residue and this chemical was widely used as a pesticide to control bat infestations in houses in the 1940s (U.S. Geological Survey 2013). It was also widely used (including aerial application) to control mosquitoes and agricultural pests in the 1940s and 50s. It was banned with few exceptions in 1972. Since DDT is highly persistent, with a soil half-life of 2-15 years and an aquatic half-life of about 150 years (NPIC 1999), it can pose a threat to bats when there is exposure to trace residues remaining in the environment (USGS 2013) or through bioaccumulation when quantities of contaminated insect prey are consumed. Extensive applications of insecticides and some bio control methods, such as Btk could also pose an indirect risk to red bats by reducing availability of insect prey.

Conservation Strategies and Management Practices [-]
Research indicates that raising cut-in speeds (i.e., wind speed at which turbines first start rotating and generating electrical power) of wind turbines during peak migration times may limit the number of migratory tree bats killed (Baerwald et al. 2009; Arnett et al. 2011). Eastern red bats may roost in the remaining large trees in urban and agricultural areas and this can be important habitat to retain for them (Mager and Nelson 2001).

Research Needs [-]
Research is needed to document specific roosting habitats in New York, and to determine population trends and regions of the state with the highest local abundances.