Silver-haired Bat

This bat species has been confirmed on Mayne Island using DNA testing. The  Silver-Haired Bat (Lasionycteris noctivagans) ranges across North America from northern Mexico to southeastern Alaska. In British Columbia, this bat uses forests and grassland habitats that range in elevation between 0 and 1220 metres. These bats migrate south to hibernate in the winter, with northern populations moving to southern regions of British Columbia.

This bat species is identifiable by its colouring which is dark brown to black with dispersed silver/white frosted tipped hairs on its back, while on its underside the silver hair is more concentrated. Their short round ears and wing membranes are black, and they have a flat skull profile. They are 8 -11 grams in weight, 9.5 -11.5 centimetres in length, and their wingspan is 27 – 31 centimetres. 

Silver-haired Bat
Silver Haired Bat. Photo: –BP–, Creative Commons

Silver-Haired Bats are typically solitary or roost in small groups of two to six individuals. They primarily roost in trees under bark, crevices in trunks, and abandoned cavities made by other species such as woodpeckers. This species does not use buildings for roosts and therefore is not a good candidate for bat houses. 

The diet of Silver-Haired Bats comprises a variety of different small insects such as moths, midges, leafhoppers, caddisflies, beetles, ants and termites. They hunt their prey from dusk until dawn, and  forage in tree canopies and over water using echolocation to find insects. Predators of the Silver-Haired Bat include owls, hawks, skunks, and occasionally other bat species. 

Changes to bat ecosystems through land use disturbances such as logging has impacted their feeding abilities and made them more vulnerable to predators. Despite the decrease in their habitat, in British Columbia the Silver-Haired Bat is not considered at risk. These bats have contracted White Nose Syndrome in other regions of North America, and as they are migratory are also being monitored for early detection of this deadly fungus.

E Fauna of BC : Silver-haired Bat

Animal Diversity Web: Silver-haired Bat

Hoary Bat

Hoary Bats have the largest distribution of any bat species in North America. They range from South America to northern Canada. In British Columbia, male and female bats share summer habitats while in other regions they separate during the summer. 

Hoary Bats are the largest bat in British Columbia weighing 20 to 35 grams, and are 13 to 15 centimetres long, with a wingspan of 43 centimetres. They are identifiable by their hoary colouring; the long fur on their back is a combination of dark brown and grey, and they have yellow and white fur on their shoulders, wrists, throat, ears, and the underside of the wing membranes. The dorsal side (upper surface) of their wing membranes is dark brown, while their forearms and fingers are paler in colour. 

Hoary Bat
Hoary Bat. Photo: John Longhenry, Creative Commons

Hoary Bats are tree bats that roost in the foliage and branches of coniferous and deciduous trees. It has been noted that they prefer trees that border clearings. Unlike many other bat species in BC, females don’t congregate in maternity colonies but instead are solitary with their young. Hoary Bats are thought to migrate south of British Columbia during colder months in search of warmer climates. 

The Hoary Bat begins foraging thirty minutes after sunset and continues throughout the night. Hoary Bats use low-frequency echolocation calls which are most effective for detecting large insects at long ranges. Their echolocation calls are well suited for their prey, which consist of large insects such as larger moths, beetles, dragonflies, and grasshoppers. Smaller insects such as midges and flies make up a smaller portion of their diet. Common predators of the Hoary Bat are owls, hawks, kestrels, and snakes. 

Like the other bat species on Mayne Island, the Hoary Bat plays an important role in pest management in the ecosystem. Currently, this bat species is not considered at risk in British Columbia, but like many other bats they are experiencing impacts from habitat loss, extermination, pesticide use in agriculture, and many other human associated threats. 

More Reading

E-fauna BC: Hoary Bat

Animal Diversity Web: Hoary Bat

BC Bats

Categories: Mayne Wildlife

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