T: 01761 233414

Alex Crossman - municipal bat roost
May 04 2015

Artificial Bat Roosts for Pest Control

Love them or not, bats provide ecological services that provide many benefits to humans. The reality is that bats are not about to suck your blood dry, nor are they looking for a human head to make a nest in. They have far more constructive things to do…

Ecological Services Provided by Bats
Some bats are fruit eaters, while others eat nectar, playing a vital role in pollination of fruit crops as well as other plants and trees that we depend upon for food and products. But perhaps the most underrated service provided by bats, is that provided by predatory insectivorous bats which consume hundreds of thousands of nocturnal flying insects, including insect pests such as mosquitoes that pose a health risk to humans.

Combatting Malaria
Recognizing their contribution in controlling insects, in the early 1900’s Dr Charles Campbell, a physician, started conducting experiments on using bats to eradicate malaria. In 1911 he built a giant bat roost at Mitchell Lake, south of San Antonio in the US, to attract and cultivate bats in the hope that they would combat malaria-carrying mosquitoes that plagued local farmers and their livestock. At the time, around 89% of people living in proximity to the lake were infected with malaria.

The bat population in his roost grew to 100,000, emerging at dusk to circle the skies preying on flying insects at night, returning to roost in his bat house at dawn. Upon examining the population three years later, he found that not one person had malaria. Farmers were no longer plagued by mosquitoes as they worked their fields. Not only had the bats eradicated mosquitoes, but at the same time they had produced tons of guano that could be used as fertilizer.

Dr Campbell soon attracted international recognition for his work, and in 1919 was nominated for a Nobel Peace prize for his contribution to humanity. Countries in Europe started erecting bat roosts to combat insect pests, and gradually it caught on back in the US too. Today, the interest in large bat roosts has fizzled out, with smaller backyard bat houses being more popular. Are we not perhaps missing an opportunity to control insect pests naturally without the use of chemical pesticides?

Natural Pest Control
It is now more than 100 years since Dr Campbell built his bat tower that showed such remarkable, positive results for combatting malaria, yet there is no strong initiative to utilize these techniques to control mosquitoes in areas where malaria continues to be problematic. Erecting large bat roosts to attract these natural insect predators as an alternative to hazardous chemicals such as DDT — which although banned in many countries is still used to control malaria in some parts of the world — is not only environmentally sound, but if Dr Campbell’s experience is anything to go by, will be far more effective in the long-term too.

Uses in Permaculture & Organic Farming
Similarly, bats offer great potential as a natural method of controlling agricultural pests. Erection of large bat roosts could be incorporated as a natural pest control method by organic farmers and those who follow permaculture principals. Fruit and nectar eating bats can help pollinate crops, while insect eating bats could be extremely beneficial in eradicating insect pests, without harming the environment or leaving any toxic residues on the organic crops being cultivated.


Every day, somewhere in the UK there is a Crossman Associates consultant providing expert advice to our clients


We'll get to the heart of your project and provide exceptional service, innovative solutions and outstanding value


Over 80% of our work is referrals or repeat business which reflects our pragmatism and client focus