(Eptesicus fuscus). Patient Number 20-1895.
Date of admission: September 23rd, 2020.
Reason for admission: Grounded, unable to fly.
Big brown bats are native to North America, Central America, the Caribbean, and the northern ranges of South America. Adult bats weigh between 15-25 grams (0.5-0.8 ounces), with a wingspan averaging 30 centimetres (12 inches). Big brown bats are nocturnal. During the day they roost in colonies, with large numbers of bats commonly found roosting in hollow trees, in the crevices of rocks, or in man-made structures such as attics and barns. The diet of these bats consists of night-flying insects, with moths being a favourite.
Big brown bats hibernate during the winter months. Winter roosts can be natural subterranean caves and mines or man-made structures. Few details are known about the hibernation patterns of big brown bats in Alberta, but it appears that winter roosts, or hibernacula, are places where the temperature remains above freezing. If the temperature of the hibernacula drops below -4C (24.80F), bats will wake themselves and seek a warmer site. This behaviour may explain the appearance of big brown bats during the winter months.
This big brown bat was found on the ground, unable to fly. At AIWC, his examination revealed no significant findings, so it is possible he had become displaced from his hibernaculum. Due to the dip in temperatures, the decision was made to overwinter him and when the warm weather once again returns, he will be released.
Thank you for helping us to keep him forever wild!