Field Notes Journal

UK Bat Emergence Times and Call Frequency Reference

A simple field reference for bat detectors: emergence timing, call ranges, likely heterodyne detector sweet spots, and broad habitat associations.

Common Name Scientific Name Emergence Call Range Detector Range Habitat Notes
Brandt’s Myotis brandtii +20 to +60 45 - 50 45 - 48 woodland, edge, garden Very similar to whiskered; clutter forager
Brown Long-Eared Plecotus auritus +30 to +90 25 - 50 25 - 50 woodland, garden, buildings Often very quiet; may hear wing rustle more than calls
Daubenton’s Myotis daubentonii +10 to +40 35 - 85 45 - 50 water, rivers, lakes Strong over water; buzzing near surface
Greater Horseshoe Rhinolophus ferrumequinum +20 to +60 80 - 85 80 - 83 woodland, pasture, buildings Constant frequency; very stable tone
Lesser Horseshoe Rhinolophus hipposideros +10 to +40 108 - 115 105 - 110 woodland, buildings, sheltered valleys High, pure tone; often first detected as steady whistle
Natterer’s Myotis nattereri +20 to +60 45 - 50 45 - 48 woodland, edge, garden Quiet, clutter specialist; often hard to detect
Noctule Nyctalus noctula -10 to +10 20 - 45 22 - 28 open, parkland, above canopy Often before sunset; loud, fast commuting
Common Pipistrelle Pipistrellus pipistrellus +5 to +30 20 - 30 20 - 30 urban, garden, edge Social / commuting
Common Pipistrelle Pipistrellus pipistrellus +10 to +40 40 - 55 40 - 50 edge, woodland, garden Hunting; feeding buzz with lower sweep audible
Soprano Pipistrelle Pipistrellus pygmaeus 0 to +30 50 - 65 50 - 60 water, rivers, wetland Strong around water
Soprano Pipistrelle Pipistrellus pygmaeus +10 to +40 55 - 80 55 - 80 water, wetland, edge Hunting; higher, sharper than common pip
Whiskered Myotis mystacinus +20 to +60 45 - 50 45 - 48 woodland, edge, garden Indistinguishable from Brandt’s on heterodyne

Notes:

  1. Emergence is expressed as time in minutes relative to sunset, with negative numbers being before sunset and positive numbers after
  2. Frequencies are expressed as KHz
  3. The detector range relates to the optimal frequency range for a heterodyne detector

The information presented here is a synthesis of widely available field knowledge on UK bats, drawn from general field guides and acoustic survey references. Frequency ranges, emergence timings, and habitat associations reflect general consensus values rather than original research. The structure, interpretation, and presentation are the author’s own.