Northern long-eared bat day roost ecology and novel bat sampling techniques in the mid-Atlantic

White-nose syndrome (WNS), caused by the introduced fungal pathogen, Pseudogymnoascus destructans, has caused precipitous declines in bat populations including the now endangered northern long-eared bat (Myotis septentrionalis; NLEB). Remnant populations of NLEB have been found outside their traditional range in areas of the urbanized Piedmont and also the Coastal Plain of the mid-Atlantic region of the United States, where little is known about their summertime day-roost habitat needs. More broadly for the species, little research has examined the day-roost habitat use of both male and females. This information is vital to inform management and policy for the conservation of this endangered species. In this dissertation, I captured NLEB at three properties in eastern Virginia and Washington D.C. Captures at Marine Corps Base Quantico (MCBQ) and Prince William Forest Park (PRWI) in Virginia were male-biased and Rock Creek Park (ROCR) captures in D.C. were female-biased. I found that overall NLEB are associated with mature, deciduous forest. Males used red maples (Acer rubrum) in later decay stages and lower crown classes at MCBQ/PRWI. Females used taller oaks (Quercus) at ROCR. Differences between the two study areas may be an artifact of MCBQ/PRWI being an early mature forest whereas much of ROCR is approaching late mature to old-growth gap-phase conditions. Building off the fact that many WNS affected bat species are now substantially more difficult to detect on the landscape, I explored novel methods to help increase detection of bats during acoustic surveys. This included developing and testing an experimental ultraviolet (UV) light lure that attracted insects and thereby attracted bats. The lure increased overall bat feeding buzz calls and had a species-specific response, primarily attracting eastern red bats (Lasiurus borealis). The lure elicited an interesting negative response from NLEB within the illuminated area, but an increase above control conditions beyond the illuminated area. Overall, the UV lure shows promise for increasing detection of bats and warrants further research, however caution should be exercised as some bats showed a negative response. I also investigated the effects of environmental clutter on the reception of ultrasonic bat echolocation signals to help researchers better understand how different clutter types and configurations affect and potentially bias acoustic survey results. This is especially important when surveying for clutter-adapted bats, such as NLEB which are traditionally biased against in acoustic surveys due to their habitat associations and low detection probability. I found that the recording angle of the bat in relation to the microphone overshadowed most other effects. On-axis recording created the best quality recording and the signal rapidly degraded as the angle increased. Therefore, placement of microphones to where bats are expected to be flying is critical. Many small clutter objects, analogous to a young forest with a high stocking rate substantially degraded echolocation signals. Fewer, large objects, analogous to a mature forest with large trees and little understory actually generated echoes that were identifiable to species that would be beneficial to improving detection probability and occupancy estimates, but might generate bias by overcalculating activity estimates.