Effect of acoustic clutter on prey detection by bats

Area of Science:

• Bioacoustics
• Animal Behavior
• Ecology

Background:

• Gleaning bats use short, broadband, frequency-modulated (FM) echolocation calls.
• These calls are thought to be effective in uncluttered environments but may be masked by clutter.
• It remains unclear if FM echoes allow fine texture discrimination or if bats use other cues in cluttered environments.

Purpose of the Study:

• To investigate the effectiveness of FM echolocation calls for gleaning bats in detecting prey within cluttered environments.
• To determine if gleaning bats rely on prey-generated sounds or other cues when echolocation is hindered by clutter.

Main Methods:

• Two species of insectivorous gleaning bats were tested on their ability to detect silent and immobile prey in cluttered and uncluttered habitats.
• Performance was assessed in capturing prey with and without acoustic cues (noise).

Main Results:

• Bats performed poorly when detecting silent, immobile prey in clutter.
• Bats were highly efficient at capturing noisy prey in cluttered backgrounds.
• Both dead and live prey were successfully captured in uncluttered habitats.

Conclusions:

• The short, broadband FM echolocation calls of gleaning bats are not optimized for detecting prey in cluttered environments.
• Gleaning bats may rely on prey-generated sounds or other sensory cues to locate prey in echo-cluttering conditions.