Have you ever wondered how far away an animal can be and still be detected by your microphone? This is a question we get very frequently.
The simple answer is that there isn’t a simple answer.
A difficult question to answer
Microphones do not have a “range” in that they will capture any sound that reaches the element inside.
Atmospheric attenuation, the frequency of the sound, the direction the animal was facing, and a large number of other conditions all affect how far away a sound can be heard.
For acoustic microphones this translates to “if you can hear it, so can the microphone”.
An owl calling from 800 meters away may be heard in a quiet forest where a mouse squeak may not be heard from 10m. Also humans have a great ability to filter out wind noise automatically, so you may be able to pick out a sound that is masked in a recording. On the other hand, there are times when you can see a sound in a spectrogram that you could not easily discern when listening in person.
When recording ultrasonic sounds such as bat echolocations, a good rule of thumb is that most bat species can be detected at a distance of 30m with a likely maximum of 100m for a very loud, low frequency bat pointing directly at you in perfect conditions.