As with all wildlife, bats are an important part of Ontario’s biodiversity. Eight different species of bats are found in this province, with Little Brown Bats and Big Brown Bats being the most common. Bats are the primary predator of night-flying insects like moths and mosquitoes. A single bat can eat three times its body weight in insects every night.
Why install a bat house? The simple answer is because having bats in the area is an easy way to observe nature at its finest, and the bats will provide a guaranteed show every warm evening of the summer season. Bats are insect eating-machines that may help keep troublesome insect populations in check. In addition, providing bat houses is one method of encouraging bats to relocate their colonies out of buildings. This year though, there is an additional, more urgent, reason...
White Nose Syndrome
White nose syndrome has killed hundreds of thousands of bats in the north eastern U.S. It was first identified in a cave near Albany, New York, in 2006. Cases have also been found in 10 other states. Mortality has been estimated to be as high as 90% in some of their hibernation caves.
In March 2010, white nose syndrome was detected for the first time here in Ontario.
The condition has been dubbed 'white nose syndrome' because some affected bats have visible rings of white fungus around their faces. The cause of the syndrome is still under investigation. If the cause cannot be discovered and eliminated, we may lose entire species of bats in just a few years.
Bats are not prolific breeders. A mating pair may have a single pup a season. Even if scientists find a cause for the disease, and can prevent further mortality, it will take decades for bats to recover the numbers they've lost in a single season.
Artificial roosts, such as a new bat house, are bats' "summer homes" and, more important, their nurseries: they use these to bear and raise their young. By creating more summer roosting and nursery sites, hopefully we can increase their health and rates of survival during the year. They need all the help we can give them.
Most nursery colonies of bats choose roosts within 1/4 mile of water, preferably a stream, river or lake. Greatest bat-house success has been achieved in areas of diverse habitat, especially where there is a mixture of varied agricultural use and natural vegetation. Bat houses are most likely to succeed in regions where bats are already attempting to live in buildings.
Bat houses should be mounted on buildings or poles. Bat houses mounted on trees are not as successful. Mounting two bat houses back-to-back on poles (with one facing north and the other south) is ideal. Where you mount your bat house plays a major role in the internal temperature. Bat houses should face south to southeast to take advantage of the morning sun. In northern states and Canada, bat houses need to receive at least 6 to 8 hours of direct sunlight. It is also advantageous to paint the house black to absorb plenty of heat (when baby bats are born, they need it very warm). Use non-toxic, latex paint to paint your bat house and only paint the outside. Your bat house should be mounted at least 10-15 feet above the ground, the higher the house the greater the chance of attracting bats.
Bat houses are most likely to attract either little brown or big brown bats. So, where do you get the bats? Bats have to find new roosts on their own. Bats investigate new roosting opportunities while foraging at night, and they are expert at detecting crevices, cracks, nooks and crannies that offer shelter from the elements and predators.
Bat houses can be installed at any time. However, it may take up to two years for bats to "adopt" a shelter. The best time to install a new bat house is in late winter/early spring, before bats emerge from winter hibernation and begin seeking summer nursery sites. Bats return from migration and awaken from hibernation as early as March in southern Canada. They will be abundant throughout the summer and into late fall. Most houses used by bats are occupied in the first 1 to 6 months (during the first summer the bat house was erected). If bats do not roost in your house by the end of the second summer, try moving the house to another location.
Bat conservation is now more urgent than ever. Visit Featherfields to choose from many different bat house models.