New York Natural Heritage Program
Tri-colored Bat
Perimyotis subflavus (Menu, 1984)
Mammals

Conservation Overview [-]
Tri-colored bats use open woodlands and riparian forests. Populations in New York and the eastern U.S. have plummeted since White-nose Syndrome (WNS) was first reported in 2006.

Threats [-]
By far the largest threat to tri-colored bats in New York is white-nose syndrome (WNS) which was first discovered among bats in a cave in Schoharie County, New York in 2006. White-nose syndrome is caused by a fungus Pseudogymnoascus destructans (previously Geomyces destructans) that is often visible on the bats muzzle and wings (Blehert et al. 2009). The fungus may invade hair follicles and cause lesions under the skin (Blehert et al. 2009). Bats wake from hibernation and consequently burn fat reserves that are needed to survive the winter and they become emaciated (Blehert et al. 2009). Extensive damage to their wing membranes and dehydration may also be contributing factors to mortality (U.S. Fish and Wildlife Service 2013).
Bats may be particularly sensitive to environmental toxins including those found in herbicides and pesticides. Although no studies have targeted tri-colored bats directly, elevated levels of persistent organic pollutants including PCBs, DDT, Chlordanes, and PBDEs have been found in a similar species, the little brown bat, in the Hudson River Valley in New York (Kannan et al. 2010). The levels found in the bats were only one to three times less than lethal concentrations reported from previous studies (Kannan et al. 2010). High toxin levels are expected in bats that obtain a high a composition of their diet from prey with an aquatic life stage. This may be a concern for tri-colored bats, as well, since caddisflies have been reported as an important food item in some regions (Carter et al. 2003; Feldhamer et al. 2009). Bats are highly susceptible to DDT residue, a chemical that was widely used as a pesticide to control bat infestations in houses in the 1940s (USGS 2013). DDT was widely used as an agricultural pesticide in the 1950s and 60s until its agricultural use was banned in 1972. Since DDT is highly persistent (soil half-life is 2-15 years, aquatic half-life is 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). Tri-colored bat populations were thought to have been impacted by heavy pesticide use in the mid-1950s (MA Natural Heritage Program 2012). Extensive applications of insecticides and some bio control methods, such as Btk could also pose an indirect risk to tri-colored bats by reducing availability of prey.
If proper precautions are not used, cavers and researchers entering hibernacula may cause disturbance that rouses bat colonies or can transport the fungus that causes WNS on their clothing (NatureServe 2013). Other potential threats may include climate change, commercial cave development, flooding and hibernacula collapse; habitat loss and fragmentation from development, hydraulic fracturing, and the construction of new wind facilities; and direct mortality from wind facilities (U.S. Fish and Wildlife Service 2013).

Conservation Strategies and Management Practices [-]
Gating mines and caves can prevent human entry while allowing the bats unobstructed access. Following proper specifications and monitoring bat populations before and after gate installation are important, however, as gating can affect the airflow and temperature in the cave, making areas of the cave uninhabitable for certain species (U.S. Fish and Wildlife Service 2013). Buildup of debris at cave entrance gates can also have the same effect (U.S. Fish and Wildlife Service 2013).

Development and Mitigation Considerations [-]
Retaining snags and dying trees can provide summer roosting habitat for tri-colored bats. Maintaining forested habitat in riparian corridors may also be important.

Research Needs [-]
Research is needed to document summer roost locations and habitat in New York and to determine the extent of local populations. Research is also needed to identify regional differences in the characteristics of quality habitat and to identify areas of the state with the highest local abundances during summer. Ongoing winter hibernacula surveys are needed to monitor trends of the remaining populations.

Regional Conservation Needs [-]
Conservation needs have not been determined for this species in New York. The extent of the current distribution of tri-colored bats in the state, as well as habitat requirements need to be determined prior to assessing specific management and conservation needs.