Photograph courtesy of Wade Alcock
Okanagan Similkameen Conservation Alliance Photograph courtesy of Wade Alcock townsend_bat
Latin Name: Corynorhinus Townsendii
Federal Status: Threatened
Provincial Status: Blue Listed (vulnerable)


  • Total length: 10 cm; wingspan: 29 cm.
  • Huge ears: 3-4 cm long (about one half of the body length!).
  • Weight: 9 grams.
  • Long dorsal fur varies from pale brown to blackish-grey; underfur is paler.
  • Two prominent glandular swellings on its nose.


  • Dry grasslands, coniferous and deciduous forests.
  • Foraging habitat includes insect-rich riparian areas, wetlands, forest edges and open woodland.
  • Summer day and night roosts include caves, old mines and buildings; these locations are also suitable hibernating sites.
  • Dependent on close proximity of roosting and foraging sites.
  • Summer maternity colonies and hibernation sites are usually within few kilometres.

  • Hibernation occurs from September to May.
  • Mating takes place from November to February, usually at hibernation sites.
  • In spring, females form summer maternity colonies, usually returning to the same site each year; males roost singly at night in scattered locations.
  • Gestation period is controlled by temperature and varies from 50 to 100 days; cool temperatures induce torpor (a lowering of body temperature and metabolic rate).
  • Female bats give birth to one young per year in late June to mid July.
  • Young grow extremely fast and begin to fly at 2.5 to 3 weeks of age and are weaned at about 6 weeks.

Food Habits

  • Bats begin foraging an hour or so after dark and feed several times throughout the night.
  • Diet consists of small moths, flies, beetles, lacewings and sawflies.
  • Prey is gleaned by these agile bats from foliage of trees and shrubs, although most insects are captured in the air.

Interesting Facts

  • A Townsend’s Big-eared Bat’s average lifespan is 16 years; bats may live up to 30 years.
  • Highly maneuverable flyer; capable of flying at slow hovering speeds.
  • Large ears funnel sound into ear canal, and may also provide lift during flight and assist with temperature regulation.
  • By the end of hibernation, a bat may lose more than half of its autumn weight.


  • Extensive land development in the Okanagan has eliminated or fragmented their habitat (low elevation forest, grassland and riparian areas).
  • Their low reproductive rate means a slow recovery rate after disturbances.
  • Nursery roosts are extremely sensitive to human disturbance; females may permanently abandon a traditional summer roost.
  • Disturbance at winter hibernating sites can cause energy loss, abandonment of the site and death.
  • Sealing mine shafts reduces opportunities for summer roosting and winter hibernation.

Management Considerations

  • Avoid the use of pesticides, particularly near wetlands and riparian areas.
  • Protect key habitat such as forest, grassland, wetlands and riparian areas.
  • Refrain from entering caves or mine shafts, particularly during winter months when bats are hibernating.

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