Issue link: https://maltatoday.uberflip.com/i/1285850
maltatoday | SUNDAY • 6 SEPTEMBER 2020 10 COMMERCIAL Nocmigging: Automated birding whilst Nick Galea is a Senior Solutions Architect at PMD working on health systems for better patient healthcare THERE are many reasons why people do birdwatching; some do it for pure enjoy- ment, some seek the science and conser- vation aspect. The study of bird popula- tions and bird migration is an important outlook into worldwide conservation concerns, such as climate change. Birds are often considered to be important bio-indicators when studying the effect of human impact on habitats. Due to their high mobility, they are often the first to leave a deteriorating environment and also the first to re-colonize when condi- tions get better. Lying right in the middle of the Medi- terranean, an ecological barrier dividing 2 very distinct continents; Europe and Africa, Malta acts as a stepping-stone for thousands of birds migrating south in Autumn and north in Spring. This makes Malta an ideal location to study bird migration. But how do we record these observations? The easiest way is by observing birds as they fly over our island or along our coasts. But a large portion of birds migrate long-distances during the night, mainly to avoid heat and predators that hunt during the day. So how can we monitor nocturnal bird migration, shortened to "nocmig"? In comes technology; and no, not a night-vision camera, but a microphone. Nocmigging is the process of record- ing an entire night from a location where bird migration is likely to occur, followed by the analysis and annota- tions of the recording the next day. Birds often call during migration, espe- cially when migrating in flocks. The ba- sic tools required for nocmigging are a microphone and a recorder. Birds often migrate very high and predicting the ex- act spot where a bird will fly over from, is not at all easy. The type and quality of the microphone used will therefore highly affect the results obtained from this activity. The higher the sensitivity of the mi- crophone and the higher the ability to favour picking up sounds coming from the sky; rather than potential noise com- ing from the ground, the better the re- sults. Typically, a parabolic microphone is used for such a purpose. The shape of the parabola helps to concentrate and amplify sound waves that hit its surface area from above. whilst reflecting away sound waves hitting from below. Birds' auditory range is very sim- ilar to the human's range and therefore a recorder that is capable of recording frequencies of up to 24,000Hz (human range is typically between 20 to 20,000Hz) is enough. Luckily, record- ers can always be replaced and do not reduce their sensitivity by time, unlike aging human ears. Recording may be easy, but what about its analysis? Do we have to listen to 8 hours of mostly silence, cars passing and dogs barking? Luckily no; technol- ogy helps us analyse sound in a visual manner using graphical representa- tions of sound known as spectrograms. This is the representation of the signal strength over time at various frequen- cies. Indeed, to listen to 30 seconds of sound, you need the actual full 30 sec- onds. On the other hand, to visually in- spect a spectrogram of 30 seconds all it takes is 1 or 2 seconds. Once you identify a shape that looks like a bird sound, you then listen to that specific segment and determine the species. Visual analysis does reduce the time to process a recording of 8 hours to about 2 hours, but what if you don't have 2 hours every day to spare for this? Or what if you have multiple recorders in different locations each generating 8 hours of recordings? That is where I start to think as a professional birder working in IT. Can we build an autonomous device that starts to record on its own when night falls, streams the data to a remote service that is processing incoming re- cordings, automatically detects and identifies bird sounds and logs this da- ta in a repository? Can this potentially send me notifications to my phone on nights with good migration and tell me what's passing over my head whilst I am asleep? This sounds like a mammoth and may- be unrealistic task, and, it probably is, but when a pain point is dissected into smaller tasks, it starts to solution begins to become more feasible and realistic. When planning such projects, one must start with dividing the task into intelli- gent tasks against non-intelligent ones. Which tasks involved can be done bet- ter by a human and which task can be done better by a computer? Automatically calculating sunset, starting recording, uploading data as it is being recorded, allowing remote con- nection, notification based on pre-set rules etc. are all tasks that albeit varying in complexity can all be programmed Research on automatic bird sound recognition is still very much lacking when compared to other areas, mostly because demand, and therefore investment, is on the low side Nick Galea