A technique for monitoring bat activity with results obtained from different environments in southern Ontario

Nocturnal activity of bats over different environments may be measured using a heterodyning device which converts the ultrasonic echolocating cries to audible "clicks." Preliminary results obtained by this method indicate that bats are more active over lakes than over streams or fields, and that activity is greater over rural areas with buildings than over uninhabited forest areas without buildings. Rain was found to depress the nocturnal activity of bats.