Biology
- Bats are not harmful. A healthy bat will never attack a human.
- Never handle a bat without thick gloves. They tend to carry ectoparasites (mites and ticks).
- They have poor eyesight but have an excellent sonar system for locating solid objects.
- The wingspan of the two most common Canadian bats, the little brown bat and the large brown bat, range from 8-14 inches.
- During the day, bats roost in dark, secluded places. At night, they leave the roost to forage for food. During the evening, they may temporarily roost to digest food and groom themselves.
- Bats can squeeze through a hole the size of a quarter, and are known for entering rooms by crawling under doors.
- Bats are the only truly flying mammals. (Flying squirrels do not fly, they glide).
- Nearly all the bats eat insects while in flight, using echolocation to home in on them. They are very beneficial for insect control. One bat can easily eat 600 mosquitoes per hour (3000 per night). A colony of 500 bats can consume over 1 million insects each night!
- Mating usually occurs in fall or winter. One or two young are born between May-July. The baby is incapable of flying for months (it will cling to its mother until it is too heavy), so it is dependent on the parents for survival through August. This maternity period is fragile, so it is best to leave them well alone (May-August).
Problem Diagnosis
IS THERE A PROBLEM? HOMEOWNER SHOULD ACCEPT NORMAL, UNOBTRUSIVE BEHAVIOR
Refer to SELF-HELP if:
- Bats are observed going in and out of buildings.
- A bat is found in a room.
- Homeowner has a fear of seeing bats around home.
- Homeowner wants to prevent odour from guano (feces) or urine accumulation.
Refer to PROFESSIONAL ASSISTANCE if:
- A bat is trapped inside a building.
- A bat appears sick or injured.
- A bite has occurred.
Self-Help
- Most bats cannot fly up from ground level. If a bat has been knocked down because of a storm, take a stick and raise it to a tree limb. At nightfall, the bat will fly away.
- To make cleanup easier, place sand beneath the roost and brush up guano.
- Proper identification is necessary: bat guano can be distinguished from mouse droppings by the presence of shiny insect parts (its also more liquid-like). Also, bat guano, unlike bird feces, never contains white colouration.
Removal of Attractants
- Take away bug lights or use a yellow light (this does not attract bugs as much).
- Take away water sources.
- Turn lights off at night.
Habitat Modification & Exclusion
"Bat-proofing" is the safest, most permanent way of defending the home from unwanted bats.
- Find entry and exit points. Wait for the animals to leave, and then patch up the entryways (under the eaves and into attics).
- The best time to act is in spring, before bats return from their annual migration or in the fall, after they leave for the winter.
- Bats can squeeze though openings as small as ¾-inch x ¾-inch, e.g. the size of a dime. They usually gain access through gaps where materials join.
- Cover all possible entry holes with lightweight wire screening, metal sheeting, or hardware cloth. This will deny their access into buildings. Be sure no bats are trapped inside by doing this well after dark.
- If you are not sure that all the bats have left the nest, hang a piece of 2 x 2 foot netting less than 4 inches in front of the entry site. This will permit any stragglers to leave, but none to re-enter. After 3-5 days, if there is no more activity at the entry site, take the netting down and plug the hole.
- When manoeuvring around in a dark space, be sure to cover your flashlight with several layers of red cellophane. This will prevent the bats from being stunned by the light.
- Avoid the maternity period when bats leave their young in the roost to forage for food.
Repellents
Moth crystals have been proven to be quite effective at repelling bats.
When Bats are inside buildings
- Close interior doors to confine the animal to a room or section of a building, then open all the doors and windows leading outside.
- Turn lights off at night to help bats find open windows and doors.
- If the animal fails to leave on its own: put on gloves and find a coffee can. Pin the can against the wall (with the bat in it obviously). Carefully slide the lid between the wall and the bat, being careful not to pinch its legs or wings and release it outside. You can also use a broom and wastebasket the same way. Never handle bats with your bare hands.
Professional Assistance
This may only be suggested when all other measures have been taken and it is determined that the bats may need to be removed from the property. We have a list of excellent buisnesses we can recommend for this procedure, please don't hesitate to call for a referral, we only give out the numbers of companies which we trust.
- Humane Wildlife Control (514-395-4555)
- In the case of a bite: If a domestic pet has been bitten, bring the pet immediately to the vet. In off-hours, emergency cases can be brought to DMV, a 24-hour veterinary service. However, this clinic, though extremely thorough and knowledgeable, is also quite expensive. If a human has been bitten, bring them directly to a hospital.
- Sick or injured bats should be placed in a box and brought to a wildlife rehabilitator. There is less stress to the animal if they cannot see their surroundings and they are kept in a quiet location. Never handle them with bare hands. Extreme care should be taken around sick or injured bats.
When Bats are outside buildings
- In spring and fall, migrating bats may temporarily roost as they move through an area.
- If bats are seen roosting during the daylight hours, leave them alone. They are only there temporarily.
- If bats are flying around at night, they are feeding on insects. Insects are generally attracted to swimming pools, and any kind of light. Enjoy the bats! They are getting rid of your insect problems.
- Bat homes can be made relatively easily. These boxes will encourage bats to stay in your area and will control your insect population. They are available at most gardening stores. It is also possible to make one yourself: construct a slanted-roofed box with no bottom. Attach a few pieces of rough wood on the inside of the box (lets bats hang on) perpendicular to the roof (hanging straight down). Securely attach this box to the branch of a tree. Each box must be installed at different heights (between 1.8m and 12.2m) in an area that is both protected from wind and oriented towards the sun in the morning. It sometimes takes a year before the bats will settle into a bat-house, so be patient!
- Cover wood or problem areas with metal sheeting or hardware cloth to discourage contact.