Modeling migration and movement of gray bats

Abstract

Managing landscapes for migratory species is challenging when migratory movement patterns are unknown. Researchers have collected sufficient data to understand summer and winter habitat use for federally listed bats, but movement between these habitats in spring and fall has not been studied extensively. In addition, movement within summer habitat is less well understood than the roosting requirements. To initiate a preliminary understanding of movement patterns of gray bats (Myotis grisescens), we gathered all occurrence and band recovery data available within the range of the species to model movement. By weighting the pathways using the population of winter and summer locations (i.e., cave roosts), we created a heat map demonstrating the likelihood of landscape use by gray bats including nightly foraging, migration, and roost switching. The resulting map highlighted 2 major areas of use during spring and fall migration: 3 high likelihood pathways through central Tennessee and 1 primary migration route between northern Arkansas and central Missouri, USA. Although future data could influence the accuracy of this map, the representation in its current form can be used to anticipate bat presence when considering industrial development such as wind turbine siting.