Bats of Toronto's High Park

In the warm summer months just after sunset, thousands of tiny, fur‑covered wings begin to flutter across the evening skies of High Park and Toronto. These are bats — the world’s only true flying mammals. These nocturnal insectivores play a vital role in our ecosystem by consuming more than half their body weight in insects each night.

Before widespread human settlement, two of Toronto’s most common species — the Big Brown Bat and the Little Brown Bat — typically roosted beneath loose tree bark or inside natural cavities. As urban development expanded, these adaptable species shifted to new roosting sites such as buildings, barns, and the undersides of bridges. This flexibility has helped Big Brown Bats remain relatively common. Little Brown Bats, however, have become increasingly rare due to the devastating impacts of White Nose Syndrome.

High Park has supported a wide diversity of Ontario’s native bats. In addition to the common Big Brown Bats, migratory bats such as the Hoary Bat, Eastern Red Bat, and Silver-haired Bat have passed through the park during seasonal movements, while Tri-colored Bats have been recorded infrequently. Small amount of irregular activity from Myotis bats has also been detected. Aside from the Big Brown Bat, seven of Ontario’s eight native bat species are considered to be at risk. Little Brown Bats, once widespread in High Park and Toronto, are now possibly absent from the park and endangered provincially and nationally.