Species of the Month May 2021: Bats

Species of the Month, May 2021: Bats

by Mary Gartshore

Female Eastern Red Bat – a common tree bat that may hibernate in leaf litter on the forest floor. They roost in high up in tree leaves during summer. They may produce up to five pups but average three
Female Eastern Red Bat – a common tree bat that may hibernate in leaf litter on the forest floor. They roost in high up in tree leaves during summer. They may produce up to five pups but average three. Photo by M. Patrikeev

Bats are the only mammal species that can fly.

According to the fossil record, bats have been capable of flight for about 52 million years.  Bats belong to the mammalian order Chiroptera with over 1400 recognized species – the second-largest mammalian order next to rodents.  Most are insectivores, but others fish, drink blood or are carnivores. Bats may be nectar or fruit feeders important for pollination and seed dispersal. There are nine species of bats in Ontario including Eastern Red Bat, Hoary Bat, Silver-haired Bat, Little Brown Myotis, Northern Long-eared Myotis, Small-footed Myotis, Tricoloured Bat, Big Brown Bat and a single old record of Evening Bat. All of these are insectivores.

Echolocation calls of Hoary Bat on left and Little Brown Myotis on right. These were recorded and displayed on a cell phone using a small bat-detector. Note the calls are green in kHz, the waveform is in red and the time on the green band is in milliseconds. Provided by Mary Gartshore
Echolocation calls of Hoary Bat on left and Little Brown Myotis on right. These were recorded and displayed on a cell phone using a small bat-detector. Note the calls are green in kHz, the waveform is in red and the time on the green band is in milliseconds. Provided by Mary Gartshore

Our bats are mostly nocturnal and navigate using echolocation – high-pitched chirps that bounce off objects and are heard by the bat’s specialized ears.  They also detect prey by echolocation.  Certain moths have evolved ears to recognize approaching bats and take evasive action. You can try a simple experiment in your backyard.  Choose a warm night near a light source and take a wine glass and moisten the rim and run your finger around the rim to produce ultra-sonic sound.  Moths with ears may fold their wings and drop to the ground.  An interesting way to liven up a late-night barbecue!

A nursery colony of female Big Brown Bats roosting in a barn roof. Photo by Mary Gartshore
A nursery colony of female Big Brown Bats roosting in a barn roof. Photo by Mary Gartshore

In Ontario, White Nose Syndrome has infected bats that hibernate in caves such as Little Brown Myotis. It is a fungal disease accidentally introduced from Europe. It is estimated that eight million bats have died amounting to 1100 metric tons of insect pests that have not been consumed, insects that may have reduced farm revenue in the eastern US by an estimated $3 billion.  One of our nature reserves has a nursery colony of Little Brown Myotis that has increased from 27 in 2010 to 127 in 2020.

This year we plan to carry out bat surveys in our nature reserves – please sign up here if you’re interested in volunteering with us.

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