Big brown bats are one of New Hampshire’s best-documented bats, with 114 records split fairly evenly between iNaturalist (79) and GBIF (88), and NatureServe still rates the state population S3, vulnerable, despite that relatively strong count, a reminder that a decent record total doesn’t equal a secure population, especially for a species hit hard by white-nose syndrome. As one of the few bats that regularly roosts in buildings, records near White Mountain National Forest and the Lakes Region likely trace back to structures and bridges as much as to natural forest roosts.
Records surge in July and August, which together account for 51 of the 114 sightings, more than four times the spring baseline, matching the weeks when maternity colonies are active and young bats first take wing. Activity falls off sharply after September, with no records at all in November, consistent with the species heading into hibernation.
Full species profile
