This dataset represents the date and related identification number for each guano sample collected from the western small-footed bat (Myotis ciliolabrum) captured at Chaco Culture National Historical Park, El Malpais National Monument and El Malpais National Conservation Area, Mesa Verde National Park, Pecos National Historical Park, Guadalupe Mountains National Park, and Capulin Volcano National Monument, USA. Additionally, from analyses of guano, percent volumes of insects consumed by M. ciliolabrum with totals for each sample equal to 100%. Some samples may not equal 100% due to rounding up of calculated percentages, particularly for percent frequency.