Night-Roosting Behaviors for the Northern Long-Eared Myotis (Myotis septentrionalis) Under a Bridge Revealed by Time-Lapse Photography

(Uploaded by Plazi for the Bat Literature Project) The northern long-eared myotis (Myotis septentrionalis) occurs across much of eastern North America and is listed as federally threatened in the United States due to pervasive population declines. Limited data are available about roosting behaviors for this imperiled species. We report on night-roosting behaviors for the northern long-eared myotis under a bridge in northwestern Nebraska. Grooming, short visits, and feeding were the most frequently observed behaviors. Grooming, inactivity, and nursing had the longest durations, albeit all averaged ,15 min per event. We also documented movement and urination infrequently. Prey manipulation associated with feeding was a frequent behavior and consisted of individuals facing upward or downward, culling wings, elytra, and legs of large prey items. When facing upward wing and tail membranes formed a cup against the abutment wall that likely limited loss of prey. Individuals used the bridge throughout the night but roosted most frequently at 4 and 8 h after sunset (00:15 and 04:15 h, respectively), with early morning activity dominated by feeding/prey manipulation. Our study showed night roosts were used frequently for many reasons, especially for grooming and consumption of large prey. Our observations represent the first description of night-roosting behaviors for the northern long-eared myotis.