Status of an anomalous population of northern long-eared bats in coastal North Carolina

Abstract

The northern long-eared bat Myotis septentrionalis was discovered in coastal North Carolina in 2007. Work began in 2015 to document the species’ distribution and behavior in eastern North Carolina, and the known range of the species has expanded from 4 coastal counties to 19. Captures occurred in all months of the year and mostly occurred in or adjacent to wetland forest. Captures occurred exclusively in the Middle Atlantic Coastal Plain ecoregion of the state, and the species has not been documented in the Southeastern Plains or Piedmont ecoregions. The lack of captures in the middle of the state suggests spatially disjunct populations in North Carolina. The bats were observed to be active throughout most of the winter and roosted in trees. During late fall–winter 2015–2018, 43 bats were tracked to 165 winter roost trees located mostly in wetland forest. The species’ winter activity in coastal North Carolina represents a novel survival strategy as opposed to the hibernation behavior it is assumed to use in the rest of its range. This portion of the state is nearly devoid of caves or mines suitable for hibernacula, but has milder winters with insect activity. During spring 2019, 21 reproductive females were captured in the northern coastal plain and tracked to 64 maternity roost trees located mostly in wetland forest. Pregnant females began to be captured on April 25 and juveniles on June 16, indicating that pups are likely born in late May. Swab samples collected during late fall–winter from species susceptible to white-nose syndrome provided no evidence of Pseudogymnoascus destructans. Since northern long-eared bats in coastal North Carolina are active most of the winter and not dependent upon caves or mines for hibernation, they are likely not susceptible to white-nose syndrome. With the species in sharp decline elsewhere due to white-nose syndrome, this coastal population may serve as a refugium.