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Pipistrelle Passes

It can often be difficult to count the exact number of pipistrelle passes, especially if a bat is remaining close to a certain spot to feed or there is more than one present. However, please do try and give an estimate.

Again, it may be best to allocate one person to counting passes at the spots, and another to focus on identifying the species. It will help a lot if you can see the bats against a moonlight sky or street lamp.

Typical Pipistrelle Calls

A call from one of the pipistrelle species is the most commonly encountered type of bat call in the UK. With your detector tuned at 50kHz at the spot, you will have the potential to hear both types of pipistrelle targeted in this survey, the common and the soprano pipistrelle.

Therefore, begin with the dial tuned to 50kHz but you will need to do a little more investigation in order to separate the species.

Pipistrelles use a series of calls at very irregular intervals. The calls have an average repetition rate of around 7-9 per second which is obviously much faster than the noctule or serotine bats (and it can be even faster in certain situations).

These little bats are incredibly manoeuvrable in the air making twists and turns to catch their prey, and this is reflected in the erratic rhythm which has a kind of galloping quality.

Listen to this typical pipistrelle call. In this example the detector is tuned into the peak frequency and the call has a deep, rich, wet slap or popping sound.

Some people say it is like the sound made when slapping your thigh with a cupped hand (try it!).

 

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