Canada’s Bats Face Growing Threat

OTTAWA, Oct. 24, 2019 (GLOBE NEWSWIRE) — Hibernating bats may be storing pesticides from contaminated insect food in their flesh over winter, lowering their immune systems and putting them at greater risk of disease and death, says the Canadian Wildlife Federation (CWF).

“Many Canadians have heard our distress signal about the harmful effects of neonicotinoids (neonics) on pollinating species and are joining CWF in calling for national monitoring and habitat recovery programs for butterflies, wild bees and other pollinators, but Canada’s bats may also be impacted and need our attention too,” said Carolyn Callaghan, senior conservation biologist, terrestrial wildlife.

Bat populations are already in steep decline and this new threat impacts an already fragile population.

 “More research is needed to understand how these pesticides impact bats and what can be done to reduce the threat. We also need to rethink how we are producing our food and build environmental sustainability into agricultural systems. Bats are important allies to food production because they are effective predators of crop pests. Keeping them safe from impacts of modern agricultural practices will also benefit farmers.”

Researchers are learning that neonics can harm bats by reducing the insect food supply. Bats go into a state of hibernation called torpor during the winter and unless they have accumulated enough body fat by autumn their chances of surviving the winter is reduced. Bats are also impacted by consuming insects that have been exposed to neonics. Research has demonstrated that neonics can impair a bat’s ability to use echolocation and to perform intricate flying maneuvers, which is critical to successfully capturing prey. Researchers have also discovered that bats can actually retain neonics in their systems over time, Callaghan said. Neonics were detected in the tissue of bats collected during the winter in the Northeastern United States. Neonics have also been shown to disrupt topor.

“This is very worrying news,” Callaghan said. “When a bat isn’t able to go into and stay in torpor over the winter its health is easily compromised.”

Canada has 19 bat species which contribute millions of dollars each year to agriculture through natural pest control. Since many of these species give birth to only one pup a year, recovery from conservation threats is slow. Five of Canada’s bat species are listed as threatened.

CWF reminds the general public not to handle bats, and has developed several initiatives to inspire conservation of these nocturnal mammals. To learn more, visit

About the Canadian Wildlife Federation:

The Canadian Wildlife Federation is a national, not-for-profit charitable organization dedicated to fostering awareness and appreciation of our natural world. By spreading knowledge of human impacts on the environment, carrying out research, developing and delivering education programs, promoting the sustainable use of natural resources, recommending changes to policy and co-operating with like-minded partners, CWF encourages a future in which Canadians can live in harmony with nature. For more information visit

Heather Robison, Media and Community Relations Officer, 306-550-6340
Pamela Logan, Communications Director, 613-599-9594 x 250

Media Backgrounder:

What are neonics?

Neonicotinoids were introduced in the 1990s because many insects were becoming resistant to common pesticides. These new pesticides — “neonics” — were a group of insecticides that were chemically related to nicotine and were known to be toxic to insects. Five of these insecticides, including Thiacloprid, Clothianidin, Acetamiprid, Imidacloprid and Thiamethoxam, have been used in Canada on crops like wheat, soy, peas, beans, fruits and vegetables. They have been applied to the plant as seed coatings, soil solutions or as sprays on the leaves and stems. They remain active in the plant for many months and in the soil for up to several years.

How do neonics affect bats?

Neonics could be impacting bats in numerous ways: 

  • Depleting insect populations — the bat’s source of food
  • Poisoning bats that eat affected insects
  • Lowering the immune system of bats and making them vulnerable to disease

Which insects do bats eat?

Bats can eat upwards of 600 mosquitos in an hour.

Bats also eat plenty of agricultural pests. The key pest species and crops where bat predation might occur include: June Beetles (grasses, cereals, sugar beet, soybeans and potatoes), Wireworms (most crops), Leafhoppers and Plant Hoppers (rice, potatoes, grapes, almond, citrus and row crops), Corn Rootworms/Spotted Cucumber Beetles (corn, spinach, cucurbits), Stinkbugs (fruit trees, corn, cereals and vegetables), Cutworms (most crops), Tortrix moths (fruit and nut trees), and Snout Moths (nut and fruit trees, cranberries).

Bats will also eat aquatic insects. For example, the Little Brown Bat is known to hunt regularly for its prey over water. In both agricultural and aquatic settings, bats will forage for insects by hunting mid-flight and also by gleaning from surfaces (including plant and water surfaces).

What are the results of exposure?

The problem occurs when neonics permeate the very insects that bats enjoy eating. Neonics are highly water-soluble and aquatic insect larvae are incredibly sensitive to these lethal pesticides. They can kill larvae, reduce the growth of affected insects, make it difficult for insects to move around and inhibit their ability to feed.

When agricultural pests are sprayed with neonics, they can be exposed to a sub-lethal amount of the pesticides or the substance can coat their wings, hairs or scales. In turn, when bats eat the poisoned insects, they can be poisoned too. Exposure to neonics may have consequences for these flying mammals because it can impair their ability to use echolocation and perform intricate flying manoeuvers to catch their prey.

What are some of the other threats to bats?

Millions of bats have died in Canada over the past ten years. A disease known as White-nosed syndrome has wiped out millions of bats in North America. Habitat loss, reduced food supplies and evictions from roost sites produce added threats to already stressed populations.

What else is the Canadian Wildlife Federation doing to help bats and other species impacted by neonics?

  • CWF has been tracking bats in the Ottawa area to see where they go after eviction from homes. This new research is supported by the Ottawa Community Foundation. Local homeowners, a wildlife control company, a bat researcher, students and community groups are also involved in the research. As part of this project, CWF is working with partners like the Naismith Men’s Shed to develop different designs of bat houses to discover which is most effective.
  • CWF is asking Canadians to report bat sightings and monitor bat houses. By adding photos and observations to the website the public can help build a national database of Canada’s biodiversity. Scientists review the submissions online and identify the species in images.
  • CWF is raising awareness of the need to conserve and recover Canada’s insect populations. Since insects are a food source for bats, birds and fish, if their populations continue to decline or be impacted by insecticides the entire food chain is at risk.
  • CWF’s petition for a national monitoring and recovery program for pollinators impacted by neonics has received more than 120,000 signatures and will be presented to the federal government this winter. This follows CWF’s 2018 petition for a five step plan to ban neonics, recover affected species, encourage research and development of safer pest control, give farmers alternatives to neonics and reform protection of our food supply.

What is the Canadian government doing about neonics?

In April, 2019. Health Canada announced the proposed phase-out and restricted use of three neonicotinoids (clothianidin, imidacloprid, and thiamethoxam), but the final decision is not expected until 2020 and there will likely be delays in implementation until 2023 – 2025. The restrictions were put in place due to impacts on aquatic insects rather than pollinators.

What are other countries doing about neonics?

After a petition to seek better protection of plant and animal species garnered 1.75 million signatures, the German state of Bavaria announced this year that they will pass a pollinator-protective law that requires 20 per cent of agricultural lands to meet organic farming standards by 2025, before reaching 30 per cent by 2030. Ten percent of green space in Bavaria will be turned into flowering meadows, and rivers and streams will be better protected from pesticides and fertilizers.

Why is CWF sounding the bat call now?

Bat week is Oct. 24-31, 2019. Learn more at

Two photos accompanying this announcement are available at:

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