The northern long eared bat recently was federally listed as threatened primarily due to the effects of white nose syndrome (WNS). Occurrence data for this species in Oklahoma is limited. Duncan Field Cave on the Sally Bull Hollow Unit of the Ozark Plateau NWR is one of 9 hibernacula in Oklahoma the species currently is known to use. About 10 to 20 individuals typically are observed in the cave during winter cave surveys. However, the number of northern long eared bats that use the cave as a hibernaculum is difficult to ascertain due to the tendency of this species to roost in small cracks and crevices and because the cave has over 9 miles of passage. Therefore, the overall relative importance of this cave as a winter hibernaculum is not currently well understood. The goal of this award is to conduct fall and spring bat surveys and a northern long eared bat banding study over a two year period at Duncan Field Cave located on the Sally Bull Hollow Unit of the Ozark Plateau NWR in Adair County, Oklahoma. The purpose of this project is to investigate use of this large refuge cave by the threatened northern long eared bat to better understand the importance of the cave to this species. The proposed project will consist of netting and or trapping at three (of the 11) cave entrances. ESI will mist net and or trap at the three selected cave entrances for two nights in the fall (October) of 2015 and 2016 and in the spring (March) of 2016 and 2017, for a minimal sampling of 24 net nights of sampling over the life of the project. Each northern long eared bat captured will be banded. A photo will be taken of each species captured and of each listed bat captured. If wing damage or any other sign of the possible presence of the fungus that causes WNS is observed, a swab sample will be collected. The following data will be recorded for all bats captured: species, sex, age class, reproductive condition, right forearm length, weight, and wing condition. ESI will provide an annual report and a final report at the end of the project.