Editing Bat detector (section)

{{Short description|Audio device to detect the presence of bat sound signals}}
{{Refimprove|date=December 2008}}
[[File:Bat detector.jpg|thumb|A bat detector on a table]]

[[File:Batbox Griffin Time Expansion Bat Detector.png|thumb|All-digital bat detector with heterodyne, frequency division and time expansion]]

[[File:Pipistrellus pipistrellus lateral.jpg|thumb|Common Pipistrelle]]
{{Listen|filename=Ultrasonic_bat_calls_short.ogg|title=Common Pipistrelle|description=Common Pipistrelle call heard on a heterodyne bat detector - 68&nbsp;KB. This is a typical echolocation call with "feeding buzzes" when it attempts to capture an insect.|format=[[Ogg]]}}

A '''bat detector''' is a device used to detect the presence of [[bat]]s by converting their [[Animal echolocation|echolocation]] [[ultrasound]] signals, as they are emitted by the bats, to audible [[Frequency|frequencies]], usually about 120&nbsp;[[Hertz|Hz]] to 15&nbsp;kHz. There are [[#Other bat detector types|other types of detectors]] which record bat calls so that they can be analysed afterward, but these are more commonly referred to by their particular function.

Bats emit calls from about 12&nbsp;kHz to 160&nbsp;kHz, but the upper frequencies in this range are rapidly absorbed in air. Many bat detectors are limited to around 15&nbsp;kHz to 125&nbsp;kHz at best. Bat detectors are available commercially and also can be self-built.