There are several species of bats found here on Vancouver Island. The Little Brown Bat is the most common species on southern Vancouver Island. Bats are an extremely important and integral part of our eco system. Using their highly successful radar to catch night-flying insects, bats consume up to half their body weight every night in moths, mosquitoes, beetles, crickets, grasshoppers and flies. For example, a single little brown myotis (weighing 6 grams) may catch up to 600 insects an hour in its preferred habitat, near water.
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. If bats are living in your attic during the spring or summer, chances are it is a nursery colony of a common species. Female bats bear one pup a year in spring; they choose dark, private attics as maternity roosts because the warm, protected conditions are ideal for rearing their pups. People in the house often hear the pups making distress calls to their mothers, who can identify their squeaking pup from among hundreds of others in a maternity roost. The pups depend on their mothers to feed them until they learn to fly and hunt on their own. By late summer, they are able to fend for themselves. In September, bats travel to a winter hibernation site, usually in a cave, old mine shaft, attic or wall void, where they spend the next 6-8 months until spring.
Bats are a federally protected, and are considered to be an at risk species. Exclusion of bats can only be done between the months of November to March as during these months it is believed that bats migrate to warmer climates. Bats can squeeze through extremely tight gaps and cracks.
Please call our company to schedule an onsite assessment. Most bat-human encounters occur when bats get into houses, usually through open windows, doors, chimneys or narrow cracks. Flying bats will leave on their own if you close the doors to other rooms, turn off the lights and open outside doors and windows. Our company also can provide a service to remove bats that have accidentally flown into your home.
The best way to prevent bats from entering the house in the first place is to keep up with maintenance. Inspect the house regularly and fill cracks under eaves and around pipes, vents, doors and windows as soon as they begin. If the holes are big enough for bats to enter (they can get through a dime-sized hole), make sure no bats are roosting inside before you plug the gaps. Not only will a decomposing bat in a wall smell, but it may also breed fly maggots and other pests.
Dangers of Bats living in your attic
Bats although beneficial in many ways, do pose a substantial risk to humans when they move into our homes. Bat colonies if left unchecked can become quite large over time. Bat guano can build up into large mounds. As with any animal feces there are many dangerous bacteria in bat guano. This poses a risk for anyone who disturbs this waste when entering the attic area. Humans can become quite ill from breathing in these pathogens. Therefore, always wear a respirator mask when investigating or cleaning a bat roost.
The other health risk involves what the bats may introduce into your home. Like any animals that live outdoors bats can develop infestations of fleas, tick, mites, and even bat bugs which are very similar to bed bugs. As the bat population in your attic grows these pests can move into the living space of your home and start to feast on humans.
Providing a Bat House
If you want to exclude bats from your house, or just want to attract bats to your yard for mosquito control, you can provide them with a safe and suitable alternate home in a bat house. Used for more than 60 years, bat houses look like bottomless bird houses. Small houses may consist of a single narrow chamber, while large ones have partitions inside to divide the space in narrow, bat-sized hangouts. Build the houses from untreated, rough- sided wood, such as cedar or pine boards. Space any inside partitions 2-4 centimetres apart, and cover one side of each partition with fibreglass window screening (do not use metal mesh) to provide a secure foothold for the bats. In cool areas, paint the box a dark color or cover the outside with tar paper to increase the solar heat absorbed by the box and position it so that it receives at least five hours of sunlight a day.
Bat houses should be installed at least 3-4 metres (12-15 feet) above the ground, where the entry is unobstructed and out of the reach of predators. Bat houses attract more occupants when they are located near a permanent water source – especially a marsh, lake or river. A bat house can be hung in a tree, but those attached to the side of a building or mounted on a pole have been most successful. Bat houses should face south or southeast to receive morning sun exposure. In regions with hot summers, they may require shade by mid-day.
Using bat houses is still experimental, therefore, if the bat house remains empty after one year, try moving it to improve the sun exposure or put up other bat houses in different locations. For more detailed information on bat and bat houses, contact Bat Conservation International*. Beyond providing bat houses, people can enhance the urban environment for bats by preserving barns, sheds, caves and snags as potential roost sites.