Seasonal and nightly activity of Mexican long-nosed bats (Leptonycteris nivalis) in Big Bend National Park, Texas

The seasonality and activity of endangered Mexican long-nosed bats (Leptonycteris nivalis) was studied by Passive Integrated Technology (PIT) tagging in Big Bend National Park, Texas. Activity of 79 bats (out of 104 total tagged bats) at Mount Emory Cave was monitored via a serpentine antenna from 26 April – 1 September 2014 and 16 June – 19 August 2015. First year return rates included 42% adult females, 50% juvenile females, and 8% juvenile males. Cave use varied by demographic; on average juvenile males were active over longer duration each night (p<0.01) and greater range of dates (p<0.02) than lactating females. The most detections of bats occurred in the morning hours (p<0.005). Individuals were present for an average of 13.9 nights (±10.3, range: 1-39). Since some tagged individuals return to the cave annually, apparent survival and redetection probabilities can be generated for this colony over time and improve our understanding of this species.