I’m going to say a word, and I’d like you to think of the first thing that comes to mind when you hear it: Bats. How many went straight to Halloween? I don’t blame you – until recently that was my first thought too. A dark, lesser known creature flying out of haunted houses and chattering through spooky caves.

            But did you know that you probably have bats living in your neighbourhood? That most of our local bats are smaller than your hand? That they can eat up to a thousand insects in a single hour? And that their species is threatened by a number of serious risks, and you can help be a part of ensuring their survival?

Life History of Bats

            Bats are mammals in the Order Chiroptera – they are not flying rodents. Bats are warm blooded, covered in fur, give birth to live babies called pups and nurse them with breastmilk. A bat’s wing is a membrane which extends off its forearm. Four long fingers extend across the wing, and they have a thumb, like a small hook, on the end of each wing.

Did you know that BC has 16 species of bats? And 10 of them can be found on southern Vancouver Island (Bats of BC). They are called ‘micro-bats’ because of their small bodies. BC’s largest is the Hoary Bat, which is up to 14cm (5 inches) in length and 38 grams (0.08 pounds) in weight. They eat insects, largely mosquitos and moths, and can actually eat their body weight in insects during a single night. Commonly found bats around Greater Victoria are the Yuma Myotis and the Little Brown Bat. Both have very soft brown fur, and are usually between 4-7grams.

            Bats can travel large distances and may not always return to the same roost every night. Sometimes they take refuge in solitude during the day or stop to rest under bridges during the night. If they get too cold bats go into a deep sleep-like state called torpor, where they lower their heartrate and metabolism to conserve their energy.

            Female bats often roost together in large groups called maternity colonies. This provides them with added protection and warmth during pregnancy and while the pups are nursing. Adult male bats usually roost alone in trees or rock crevices because they need cooler temperatures for sperm production.

            Bats mate in the fall and give birth in the spring. It is believed that bats form large swarms during which the mating happens. During the winter bats either migrate south as far as Mexico, or they hibernate together in caves. If the climate isn’t right or there are other dangers, a pregnant female can actually control her hormones to slow the pregnancy and delay giving birth until conditions are improved enough to offer the pup better chance of survival.

            Bats cannot fly at birth. Newborn pups are lifted to the mother’s chest where they hold on until they can fly at about four weeks old. Birthing season is usually mid-June to early July. By the time a female gives birth, the pup is about one-third her body weight.

Bats become reproductive when they are one year old, and some are known to have lived up to 40 years, meaning one female could theoretically give birth to 39 pups in her lifetime. Our local bats can only have one pup per year, and not all of them survive meaning that population growth among bats is slow, and threats from disease, weather and habitat loss threaten adult survival.

Threats and Risks

            Half of the 16 BC bat species are considered threatened or vulnerable. The two biggest threats facing bat populations today are habitat loss and White-Nose Syndrome. Deforestation and urban development has forced bats to seek shelter among human buildings. Misconceptions about bats being dangerous pests can lead to colonies being exterminated and increase the species decline. One of the best things that you can do to protect bats from White-Nose is learning about what types of bats live in your area, what benefits they have, and how to make urban areas safer for bats.

Benefits

            Bats are very important for keeping insect and arachnid populations under control. While this has daily benefits for the average person hoping to avoid mosquito bites, it also has a bigger benefit as it reduces the amount of potentially harmful pesticides used in agriculture to keep insects from destroying crops.

            In addition to eating insects bats also consume nectar, meaning that alongside bees and butterflies, bats are pollinators. It isn’t as common as with other pollinators like bees, but there are 528 plant species worldwide where pollination by bats does occur. Tropical fruit bats contribute to pollination of fruits like bananas, mangoes, agave and durian, part of a trade industry worth millions of dollars ever year – so bats serve an economic impact too.  

            Bat poo (guano) is rich is nutrients and excellent fertilizer for forests and gardens. Bats who consume seeds also spread the seeds in their guano which aids in plant reproduction. When bats roost in caves their guano adds nutrients to the cave ecosystems which benefits salamander, fish and invertebrate species living there.

            Bats can also be used to predict climate change. They are considered a biodiversity indicator species meaning they respond to environmental disturbances like extreme weather and air pollution in predictable ways that can be monitored and tracked. Climate change like drought, heat, cold and rising sea levels as well as agriculture intensification, habitat loss can all be detected through change in bat numbers and activities. High disease rates among bats may be an early warning sign of coming change (International Scholarly Research Notices).

Coexisting and Protection

            The first step you can take to protecting bats is learning about them, and learning about their presence around our communities. During the spring and summer months is when they are pregnant and caring for newborn pups. This is the time of year when they cannot be disturbed. People who find bats living in their home or a building on their property and want them moved should wait until the fall when they leave on their own and then block the entrance and put up an alternative roost, such as a bat box or condo.

            If possible, leaving an old building like a shed or barn in a remote part of the property is an ideal place for bats to roost or form a maternity colony away from a house. Bats are at risk from noise and light created by humans, and need warmth, quiet and darkness in their roosts.

            Bat boxes should be put up high – at least 3.65 meters or 12 feet – attached to a pole or the side of a building, facing south or southeast with a decent amount of sun per day but not in a place that will exceed 40 degrees Celsius, and away from branches or other objects that block the entrance (Community Bat Programs of BC) . Contact HAT for more information.  

Myths and Facts

            Myth: “Blind as a Bat” – Bats are nocturnal, meaning they mostly fly at night. They have exceptional hearing and use echolocation to find fruit or insect prey in the dark. But their eyesight is very strong, and it is believed may actually be better than humans (Britannica) They are sensitive to light. If you must use a light around bats, red is the best colour as it won’t disturb them like a typical white light would.

          Myth: “Bats are Dangerous” – There is a very small chance that some bats might be carrying rabies. Like with any wild animal, humans should avoid touching and getting too close to them. Unless they are being disturbed in their roost they have no reason to harm or attack humans (Batwatch.ca)

     Myth: “They’ll Fly Into My Hair” – Bats do not want to get stuck in human hair. While flying at night their main goals are finding food and avoiding predators like owls. If they fly near a human their echolocation will help them avoid direct contact (Batwatch.ca)

Written by Darcy Harnadek.

References

Community Bat Programs of BC - Where to install a bat box - BC BATS and Bat basics - BC BATS

CSBQ-QCBS Neighbourhood Bat Watch - Bat myths | Neighbourhood Bat Watch

RRVFN Canadian Bat Box Project - Canadian Bat Project – RRVFN

Government of British Columbia Bat Conservation - Bat conservation - Province of British Columbia (gov.bc.ca)

Guillen, Aaron (2021) Capital Daily - ‘Too close to home’: bats across the Island face a looming threat that has devastated bats elsewhere - Capital Daily

Wild Birds Unlimited Nature Shop Bats of BC - Wild Birds Unlimited - Nature Shop (wbu.com)

Britannica - Are Bats Really Blind? | Britannica

Kasso, Mohammed (2013) - Ecological and Economic Importance of Bats (Order Chiroptera)

Habitat Acquisition Trust - Habitat Acquisition Trust (hat.bc.ca)