Townsend's Big-eared Bat

Townsend's big-eared bat being weighed and measured

Townsend’s big-eared bat (Corynorhinus townsendii), is blue listed (at risk) in British Columbia. A nursing female will consume her weight in insects each night, which is equivalent to an adult human eating 230 hamburgers in 6-8 hours!

Map

Biodiversity Interactive Map - Townsend's Big-eared Bat

Range

• From southern Mexico through the western United States into southern British Columbia.
• Populations occur throughout the Columbia Basin (Cranbrook, Creston, Castlegar, Trail, Slocan Valley)

Habitat

• Occurs in a wide variety of habitats (upland, wetland, dryland and riparian) primarily at low elevations
• Prefers relatively cold places with stable temperatures throughout winter for hibernation.
• Maternity roosts found in caves and anthropogenic structures

Reproduction

• Mating occurs in November through February in the hibernacula.
• Females form maternity colonies of a dozen to several hundred, and give birth to their single young after gestation of 50-100 days.  Delayed implantation of the fertilized egg in the wall of the uterus can increase this gestation period so that births occur at a time when survival of the young is most likely.
• They form tightly packed clusters in order to reduce heat loss and thus promote rapid development of the young.

Listing and Date

Threats to Species

• Loss of foraging and roosting habitat through land development (agriculture, reservoir creation, mine deactivation)
• Disturbance at maternity roosts and hibernation sites

Select Reports

• The Kootenay Community Bat Project: 2005 Summary Report 
• Roosting Behaviour of Townsend's Big-eared Bats (Corynorhinus townsendii) and comments on other bat species found at Fort Shepherd in the West Kootenay of British Columbia
• West Kootenay Townsend’s Big-eared Bat (Corynorhinus townsendii) Final Report
• Summary of Bat Work in 2009 in the Columbia Basin as Part of the Provincial Taxonomic Study of Long-Eared Bats in BC

Full Report Listing (most recent on top)

• The Kootenay Community Bat Project: 2005 Summary Report
• Fort Shepherd Townsend Big-Eared Bat Project Geological Setting
• Townsend Big-Eared Bat in the East Kootenays
• Roosting Behaviour of Townsend's Big-eared Bats (Corynorhinus townsendii) and comments on other bat species found at Fort Shepherd in the West Kootenay of British Columbia
• A Summary of Bat Research in the Pend d'Oreille Valley in Southern British Columbia
• Location of Suspected Bat Hibernacula
• The foraging and roosting ecology of the Myotis bats of the Interior Wet-belt, British Columbia
• A Survey of the Abundance Diversity and Roost-Site Preferences of Bats in the Pend D'Oreille Vallty, British Columbia
• Upper Kootenay River Bat Survey
• Conservation of the Saint Eugene Mission Townsend's Big-eared Bat (Plecotus townsendii) Colony
• Roosting habitat assessment & inventory of bats in the Mica wildlife compensation area

For more information on this species, visit The BC Species and Ecosystem Explorer and enter “Townsend’s big-eared bat” in the Species Name field.