Westward Expansion of the Evening Bat (Nycticeius humeralis) in the United States, with Notes on the First Record from New Mexico

The general lack of trees in the Great Plains has limited colonization by eastern woodland mammals in the past, but recent expansion of forests in corridors along prairie waterways and in towns has enabled an assortment of woodland species to expand distributional ranges westward. The evening bat (Nycticeius humeralis) historically occurred in woodlands throughout the eastern United States. Following our capture of the first evening bat in New Mexico, we updated the distributional range for this species by amassing recent records from published literature and museum voucher records west of its historic range published in 1981, the last time the species distribution was updated throughout its range. We document that evening bats, including some reproductively active populations, now occur across much of the central and southern Great Plains, including southwestern Nebraska, western Kansas, and western Texas. Such records should encourage researchers to factor in the possible occurrence of this species beyond published historic western limits for mist-netting and acoustic surveys. While it remains unclear if the single capture in southwestern New Mexico represented a wandering individual, these compiled records suggest that established populations might occur west of our updated distribution for the species.