Join us for an evening walk through Four Mile Run Park, as we listen for frog calls and record bat calls using an ultrasonic microphone, to add to observations in the City Nature Challenge. We will meet at the parking area between Frank Mann field and the softball field near the end of Commonwealth Avenue. In the event of rain cancellation, the bat and frog call walk will be rescheduled for Saturday the 1st - same bat time, same bat channel!