Bats are among the most widespread of mammals, but are also some of our most misunderstood, possibly because they are active at night and rarely encountered by people. However, bats do ecologically important jobs for people and are important parts of many ecosystems in Manitoba and around the world. The most obvious benefit of Manitoba bats results from their role as the primary predators of night-flying insects. Bats eat enormous quantities of moths, beetles, and other insects, many of which are pests of crops and forests. Recent studies from other parts of the world have highlighted the importance of insect-eating bats in controlling forest damage by insects and saving farmers millions of dollars in crop losses and pesticide costs.
In Manitoba we are lucky to have a number of caves in the inter-lake region that, each winter, house tens of thousands of hibernating little brown bats. The bats also use the caves as focal points for mating in early autumn, when they form “mating swarms” of up to thousands of individuals. They do not roost in the caves during the fall mating swarms but likely roost in nearby forest until the beginning of hibernation, later in the fall.
Thanks to banding data collected by the Manitoba Speleological Society, we know that some of these individual bats return to the same caves each winter. Little brown bats can live over 30 years in the wild and some individuals outfitted with forearm bands in the late 1980s) have been returning to the same caves each winter for nearly 20 years. See the blue band just peeking out on the right forearm of one of the bats in the photo above – this is an old bat!
Despite what we know, we still have a lot to learn about these animals that is critical for protecting their populations. These bats spend the winter in the caves and then appear to move throughout the province (and possibly into Ontario, Saskatchewan, and the United States) during summer, roosting in trees, cottages and other buildings. It is critical to understand where, when and how far these animals are moving, especially in light the new threat to bats from White-nose Syndrome (WNS). WNS first appeared in New York state in 2006/2007 and has
spread throughout the northeastern U.S. and into Ontario and Quebec in only 4 years. Mortality rates reach 100% in some caves and over a million bats have been killed so far. Information from the public about bat colonies is critical for helping us understand the movements of bats and hopefully figuring out ways to address this devastating wildlife disease.
We are very grateful to the Manitoba Hydro Forest Enhancement Program for funding the Manitoba Bat Blitz.