Cicada Found! No, not in the UK. Yet.

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Posted by Davide, 28 June 2013

So we set off for Slovenia for the second time, armed with the same devices we had last time, plus a few news ones. Professional field recorder with parabolic microphone, bat detector, iPhone 3, 4, 4S, 5, Samsung Galaxy tablet, Galaxy Mini (cheapest Android on the market), lots of Nexus 4's and an HTC One X. The difference being that this time we had our own Cicada Hunt app to use, and intended to find ways to break it.

Result? Two minutes after we got off the car, we found a Cicadetta montana (i.e. the New Forest cicada) and, somewhat to our surprise, the detection was perfect from the iPhone 5, our most sensitive device, all the way down to the Galaxy Mini, our cheapest device. Yes ok, the iPhone 5 could pick up cicadas from far away, the Galaxy Mini had to be a bit closer, but the sensitivity of the microphone is beyond our control. We should also mention that we knew where to go to find cicadas, while in the New Forest the task is a bit more challenging -- cover the entire 600 square kilometres area to find them. Challenging, but certainly possible.

One more thing I wanted to share with you is what we learnt from this experience. Here are a few things:

  • Of all our tools, Cicada Hunt was by far the best. The reason being the fact that you can see what you are (or aren't) hearing, so you don't have to strain your ears to pick up these really high frequencies. Also, if you got distracted, you can see the last 30 seconds in the visualisation on the screen. Priceless. I know I'm a bit biased but I truly think it was our best tool to find the bug.

  • The second best device was the Bat detector. It's great because it lowers the frequency of the cicada (we have a heterodyne one) and again it's a lot less effort to hear the call. For example, I can hear the cicada when it's relatively loud, so towards the end of the call; with the bat detector you start picking it up as soon as it starts singing. It's fairly cheap and extremely easy to use (just tune it around 16 kHz). And incidentally you can use it to pick up bats too :-)

  • The professional field recorder was useless. I could hear no cicada with that thing on, I don't know why. I suspect the headphones couldn't reproduce high frequencies very well, so it was much easier without it than with it. Obviously you can still record the sound and then analyse it on your computer afterwards, plot a spectrogram and you'll see the cicadas. But for real-time detection, useless, unless you process the sound immediately.

  • Finally there was no way to find the cicada without sound. This is not me speaking, it's the professional entomologists, world leading researchers in European cicadas, who kindly guided us through our journey.

In the end with recorded over one hundred different calls. The app sometimes also picks up Cicadetta brevipennis and Cicadetta cantilatrix, because they sound like the montana and the dark bush cricket Pholidoptera griseoaptera, respectively. This is ok, since no such species is present in the UK, but eventually we might want to classify them all as separate species.

In conclusion it was a great experience, we extensively tested the app and very rarely got a wrong result, found loads of cicadas and even saw one (the one in the picture here). It's a rather old female -- she's been adult for some three weeks -- and was photographed by Tomi Trilar, one of the amazing entomologists who took us around the sites. Many thanks to him and Prof Matija Gogala for their continued guidance and teachings. What a great result after one year of hard work!


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