Posted: 5th November 2015

The New Forest cicada (Cicadetta montana) is a rare insect native to the UK in great danger of becoming extinct. It's the only species of cicada native to the UK and despite several entomologists actively searching for it in the past few years, no sighting has been confirmed for over a decade.

The cicada call is difficult to recognise, sounding like a high-pitched hiss that is at the upper limit of our ears' frequency range. Humans can hear sounds roughly in the range of 20Hz to 20kHz, but with age this range greatly reduces. The cicada’s song is focused at 15kHz meaning that most adults can no longer hear it.

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. It is hoped that this citizen science initiative will enable researchers to rediscover the New Forest cicada. The research team is made up of academics from several universities and is headed up by Oxford Professor of Computer Science Alex Rogers.

The app uses the microphone of a smartphone to capture the sound in the surrounding environment. This sound is analysed on the phone itself to provide immediate feedback on whether the cicada is there or not. In both cases, if a visitor to the forest completes a survey (by tapping on the cicada image in the detector page), the app will send a report to the project team with location and time of the survey, and the result of the cicada detection. If the app has detected an insect call that is similar to a cicada, it will also prompt the member of public to upload a recording so that it can be analysed in more detail.

So far, over 10,000 reports have been submitted using the app, but no sign of the cicada has been detected. In 2016, as well as the existing approach with the CicadaHunt smartphone app, the research team will also be deploying small low cost cicada detectors. These combine a small low-power microprocessor with a sensitive microphone, and are capable of detecting and recognising the high frequency calls of the cicada. 100 of these detectors will be deployed at prime spots in the forest; sunny south-facing clearings. The detectors originate from a new project - www.soundtrap.io - that seeks to develop low-cost open-source acoustic tools for environmental monitoring.

‘Open-source hardware and low-volume manufacturing of custom devices has made huge advances in the recent years; largely driven by online maker communities. We hope that soundtrap.io will provide a flexible low-cost tool that ecologists can use and adapt to their specific scientific needs.’ says Professor Alex Rogers.

Read all about the New Forest cicada and download the app from the project web page http://www.newforestcicada.info.