The New Forest Cicada (Cicadetta montana s. str.) is the only cicada native to the UK. During May to July it sings with a very characteristic high-pitched song, which is at the limits of human hearing, and is particularly difficult for most adults to hear. Sightings of the cicada within the New Forest date back to 1812, but the last unconfirmed sighting was in 2000. However, it's quite likely that colonies remain undiscovered in less visited parts of the forest. The New Forest Cicada Project aims to equip the millions of visitors to the forest with a smart phone app that can detect and recognise the song of the cicada, and hopes to rediscover it in 2013.
On these pages you can find information about the research team, the project, and the progress so far. Follow our progress on Twitter and Facebook, and subscribe to our mailing list! Once available, you will be able to download the app. Please don't hesitate to contact us for any queries regarding the project and its related work.
As anyone who’s been following these blogs will know, we still haven’t found the cicada. But that doesn’t mean that it isn’t still there in some as yet undiscovered spot. In 2016, as well as the existing approach with the CicadaHunt smartphone app, we’ll also be deploying small low cost cicada detectors. These combine a small low-power microprocessor and a sensitive microphone, and are capable of detecting and recognising the high frequency calls of the cicada. We’re hoping to deploy 100 of these detectors at prime spots in the forest (sunny south-facing clearings). The detectors originate from a large project (www.soundtrap.io) to develop low-cost open-source acoustic tools for biodiversity monitoring, and we’re really excited to be able to try them next year.
Today I wanted to share with you something a bit more technical about the call of the cicada. You may have seen on twitter that a few days ago we got excited about a very promising recording that triggered our cicada detection. It turned out to be, most likely, the very common Roesel's bush-cricket, in the picture here.
This bush-cricket is actually an insect that our algorithm is capable of classifying, normally at a good level of accuracy. It starts singing as the cicada season is coming to an end, around mid-July. But the most tricky aspect is that its call is actually very similar to that of the New Forest cicada, at least when recorded at 44.100 Hz (that's the sampling rate rate we use, and it's very common. Most commercial music, CDs and MP3 are distributed at this rate). They both have a very strong high-frequency component, and while the Roesel's bush-cricket's frequency range is a bit wider, this is not always visible if the recording is not perfect. Below you can see a spectrogram and a waveform of the two calls, where the Roesel's one is the one that got us hoping. If you look closely you will notice another thing. The call of the bush-cricket shows some very rapid chirps, which are actually even more noticeable when you listen to the sound. Don't be fooled by the pattern of the waveform (the blue line, which represents the amplitude, or the volume, of the call over time). The spikes you see are actually other noises around. In the case of the cicada, it's a car passing by.
Why am I telling you all this? Well, you've been searching cicadas for two years now, and we told you that listening to its call is the best way to find it, whether with a phone or with a good pair of ears. Now, we wanted to share something a bit more detailed about what you were actually looking for. There is plenty more to say, but I'm sure I'm starting to bore you already. So that's all for now, but as usual stay tuned for more news.