The benefit of bats on Alberta farms and ranches 

  By Alan Kausy

A recently held webinar illustrated the importance of maintaining healthy bat populations to ensure Alberta agriculturists reap the rewards that the ‘night insect controllers’ bring to farms and ecosystems.

Promoted by Sturgeon County and hosted by Christine Campbell of Alternative Land Use Services (ALUS), viewers of the online seminar gained applicable knowledge from Susan Holroyd, who represented the Alberta Community Bats Program (ACBP).

Ms. Holroyd was raised on an Ontario apple orchard before earning a Master’s Degree in the behavioural ecology of bats from the University of Calgary. She has over 30 years of related experience and serves as Calgary’s Regional Coordinator for the ACBP.

Worldwide, over 1400 bat species exist, with 18 of those based within Canada. BC has 15 species, while Alberta is home to 9 varieties. Within Alberta, three bat types are migratory, and it is assumed they journey to coastal regions and likely Mexico. These species are the hoary eastern, red, and silver-haired bats.

The remaining 6 Alberta bat types are the little brown myotis, northern myotis, western small-footed myotis, long-legged myotis, long-eared myotis and the big brown bat. Myotis is a term that means ‘mouse-eared.’

Bats, classified as mammals, belong to chiroptera’s scientific order, which means ‘hand wing.’ Bats generally live less than 20 years, but some can live well beyond 30 years of age. They only give birth to 1 ‘pup’ per season, and only half of the pups will survive the winter. For this reason, rebuilding a depleted population takes many years.

Less than .5% of bats carry rabies, but bare skin exposure to a bat should be followed by a visit to the hospital as a related vaccination may be needed.

The bat diet consists primarily of moths, mosquitos, beetles, and biting flies within Alberta. These insects are pests to livestock and cause damage to crops. For this reason, they remain incredibly beneficial to agriculturists and ranchers.

Pesticides are heavily relied upon to exterminate plant damaging insects, but a substantial bat population can significantly reduce the applied amount of these chemical-based products. This is one of the reasons it is estimated that the financial value of bats to North American agriculture is beyond 20 billion dollars.

The high-frequency sound a bat makes is described as a ‘soundscape of fear’ insofar as when moths hear it; for example, the moths immediately leave the area, eliminating them from laying eggs among vegetation.

Humans detect sounds of up to 18 hertz while bat calls fall between the frequency ranges of 20 to 40 Hz. This allows animals like dogs, horses, cows and cats to detect their presence. Interestingly, electronic bat detectors are available for under $200 and can be hooked directly to one’s phone. They can even identify the specific bat species by their echolocation.

Ms. Holroyd stated the three key aspects for providing habitat conducive to bats on farms are connectivity, diversification and retention. Considering insects breed at different seasonal intervals, one should create a staggered food supply source by diversifying crops.

Maintaining windrows to establish windbreaks is vital as some bats do not like flying over open areas. Insects also gravitate to the trees, especially during windier weather. The retention of bat habitat land features is also vital. Retaining old trees, wetlands and native vegetation, and providing a water source while reducing pesticide use, are all good practices.

Open ponds can be a liability as bats can drown if there is no way to escape. Therefore, it is recommended that logs be laid within the water body to provide a means of escape.

Bats cannot escape slippery-sided chimneys or pails, so it is suggested that screens be installed atop chimneys and buckets be stored upside down. Flypaper is a hazard, as is the invasive burdock plant species. A bat can get stuck within burdock thistles. Wind turbines are a threat, as are cats, and even too much nighttime lighting can be detrimental.

Establishing multi-chambered, rain-tight bat houses constructed with non-treated wood is beneficial as long as they are protected from the wind and mounted 3 meters above the ground. East-facing locations are best to maintain temperature equilibrium.

One can discover further information and bat box designs, downloadable guidebooks and even a children’s activity book by visiting the Alberta Community Bats Program website, www.albertabats.ca.