Hung up on bats...
Black bats and pumpkins are common this time of year, or are they? Ironically we hang up bat decorations about the time when bats leave our communities to return to their hibernation sites. There are almost 1200 species of bats, that’s one quarter of all mammal species. They have many important ecological functions worldwide: pollinating flowers, dispersing seeds, and here in North America - keeping insect population in check.
Fourteen species of bats live in the Okanagan and Similkameen valleys out of eighteen species that occur in Canada. The great bat diversity is due to the variety of habitats we have from rocky bluffs, to forests, lakes and grasslands. Each species has its favourite habitat and diet. The Pallid Bat hunts over sage and antelope-brush grasslands and the vineyards that have replaced this habitat. They feed on larger insects on the ground such as grasshoppers, June beetles, and even scorpions.
The Big Brown bat forages over forests, lakes and urban areas for moths, termites and flies, while the Little Brown Bat chases tiny midges and moths. Bats play a valuable role in controlling insects, including many agricultural pests. Some species glean insects off foliage while most catch insects in mid-air. Bats emit sounds that echo off surrounding objects and return to their large ears. Echolocation allows them to target flying insects which they usually scoop up with inside their tail membranes.
Several species of bats in the Okanagan are considered “at risk” because of their small populations. Finding roosting habitat and sites for maternal colonies are the factors that limit bat populations. Females roost in maternal colonies where they give birth to one young and feed them milk for a few weeks before the young learn to fly and feed on their own. Male bats roost alone or in small groups in rock crevices, trees or under eaves and other man-made structures. Some bats take a break to rest and digest their food at night and may visit a night roost for a short nap.
Fall is a good time to make repairs to houses and sheds if you want to prevent bats from getting into structures. By now resident bats have gone to their winter quarters in caves and old mine shafts while other have migrated to warmer zones. If you are keeping bats out of a place the frequent consider putting up a bat box to replace the habitat they have lost.
Destroying a maternal colony can be a disaster to a local bat population so anyone in this situation is asked to contact the Ministry of Environment to get advice on erecting an alternate structure. Two well-known bat colonies in old school building in Cranbrook and Peachland were preserved and taken up as conservation projects by the local citizens. In some areas tourist flock to well-known bat colonies to witness evening flights.
Heading off to winter hibernation sites, mature bats will socialize and mate before going to sleep for six or more months. During hibernation their heart rate may slow to 5 beats per minute, they lose up to forty percent of their body weight, and their temperature may be only slightly greater than the surrounding air. Hibernation sites have high humidity and a temperature that stays above 4o Celsius.
Bats are protected by the BC Provincial Wildlife Act. The Pallid Bat, Western Red Bat, Spotted Bat and Townsend’s Big-eared Bat are considered species at risk. Very little is known about where bats hibernate in our province. The black and white Spotted bat, roosts in the crevices of cliffs above Okanagan lakes. Its large ears are as long as its body and unlike most bats, its echolocation clicks are audible to human ears. It feasts on moths until late October then disappears. It may hibernate deep in cliff crevices but this is only speculation.
If you would like more information on local bats or how to build a bat boxes contact outreach@osca.org.