Little Brown Myotis
Far from being pests, all species of bats found in British Columbia are voracious insect predators. Bats eat up to half their weight every night in moths, mosquitoes, beetles, crickets, grasshoppers and flies. A single little brown bat may catch up to 600 insects an hour.
Yuma myotis (Myotis yumanensis) is only found in the southern part of British Columbia.
Bats enter a building for a variety of reasons, including simply flying in by accident. They may use buildings as a temporary, daytime roost, as a nursery to rear their young or, occasionally, as a hibernation site. Attics are a favorite bat refuge.
How we can help
Eight of the 16 bat species in B.C. are currently listed as potentially endangered or threatened. Bats eat tonnes of insects per year and are therefore susceptible to poisoning by pesticides. These poisons accumulate in the fatty tissues and are released during hibernation, migration or stress and can also be passed on to nursing young. Bats also pick up toxins from roofing and insulation materials and treated wood (i.e. Lindane) and PCP (pentachloropherol). Roosts should never be treated with chemicals.
To encourage bat populations in your neighborhood but not in your attic, bat houses are a “human-friendly” solution.
A long with the many other benefits bats provide, their droppings, otherwise known as guano, makes for phenomenal fertilizer! Guano has long been mined from caves around the world for use as fertilizer due to its high concentrations of nitrogen and phosphorous. It provides some of the world’s finest natural fertilizers for both commercial production, and for local farming purposes in places throughout Southeast Asia and Latin America.
However, large-scale guano harvesting can have huge impacts on bat colonies. Bats are extremely sensitive to disturbance, and harvesting guano while bats are roosting can cause pup loss and abandonment of caves/habitats. Lack of understanding of these impacts, coupled with unclear property rights and lack of any rules to enforce, have led to unsustainable guano harvesting practices. It is extremely important to collect guano when the roost is empty. Harvest guano in the winter months, when the bats have left their summer roosts, in order to ensure you don't disturb them.