Unsure Pipistrelle Passes
If you record a pipistrelle with a peak frequency of (49kHz, 50kHz or 51kHz), because there is overlap between the species you cannot be sure which it is. If you do record a pipistrelle at these frequencies mark it as ‘unsure’.
In some cases you will be unsure because you are unable to find the peak frequency. This may be because the bat flew away too quickly. If you cannot find the peak before the bat flies away but you think it was a pipistrelle, then mark it down as ‘unsure’.
Remember that if are not able to find a clear peak, it may also be because it is a Myotis bat. These make shorter and faster calls and the peak frequency is a lot less clear. Although Myotis can be heard at 45 and 55 kHz the pitch of the call does not change.
In general the pitch stays the same right the way through the range which is usually from around 30kHz to 80kHz. (See the detector skills section for a reminder).
If you think it was another species than either a common or soprano pipistrelle do not record it on the form as ‘unsure’. You may record it on a separate sheet for interest.
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