Deployment of biosonar in diverse tasks by FM echolocating bats

Using an infrared body‐heat‐imaging video camera and a microphone array, we made field recordings of FM echolocating bats (Eptesicus, Myotis, Pipistrellus) while they deployed their sonar alone or in company with other bats. We observed cruising flights of bats in transit from roosts to feeding areas, bats flying low over water for drinking or hunting, and aerial interception maneuvers in open areas (larger insects were visible, too). However, we also recorded frequent captures of insects on or near the ground, flights into vegetation to capture beetles, and groups of bats flying in close proximity while drinking or making aerial captures of insects. Bat‐to‐bat dogfights were common, some involving two or more bats diving and violently maneuvering close to the ground or near vegetation. For single bats or several bats not very close to each other, we recorded typical interception maneuvers with pursuit sequences consisting of search‐, approach‐ (tracking‐), and terminal‐stage signals. By reconstruction of flight and emission patterns, we found that bats flying in close proximity alternated their broadcasts, and large aggregations of bats feeding close together perpetually emitted sounds characteristic of the mid‐approach stage, with short durations, high repetition rates, and no discernible terminal stages.