Case Studies

Recording nocturnal bird migration

redwing_nigel_harris.png

Nocturnal bird migration can be monitored by recording the flight calls of vocal species. However, it is difficult to configure recorders with triggers to record bird flight calls (unlike the configuration for triggers to record bat echolocation calls).

This necessitates continuous recording through the hours of darkness, and then hours of manual processing to find calls of interest. Such a workflow is impossible to scale across multiple sites. 

For a research project assessing the response of migratory thrushes to artificial light at night, we deployed acoustic recorders at over 20 locations, each for up to 14 nights. 

To process the thousands of hours of audio we trained a convolutional neural network to automatically detect and identify flight calls of Redwing, Song Thrush and Blackbird. 

Subsequent versions of this classifier will soon be available within the Acoustic Pipeline.

• Read a summary of the peer-reviewed publication, Nocturnal flight calling behaviour of thrushes in relation to artificial light at night (Gillings, S. 2021. Ibis 10.1111/ibi.12955)

Bat surveys for scientific research

Ryevitalise – Bats and Ancient Trees

ryevitalise-bat-survey-guy-harris.jpg

Working with a network of volunteers, static acoustic bat detectors have been deployed over a number of survey seasons, to provide extensive bat data for the Ryevitalise Landscape Partnership Scheme area of the North York Moors National Park.

In 2022, the project surveyed 100 different locations and recorded on a minimum of 160 different nights, mainly between May and the end of September. This amounted to a total of 413 nights of recording effort across all the sites.

Sound recordings were uploaded to the BTO Acoustic Pipeline by volunteers, and an initial automated analysis was carried out to find likely species records. These were subsequently manually verified. Overall, the project collected 581,251 recordings.

Analyses and validation revealed these recordings included 278,447 bat recordings and 427 small terrestrial mammal recordings.

• Read the Ryevitalise – Bats and Ancient Trees: 2022 Report >

Quantifying the impact wind farm development on bats – Southern Scotland Bat Survey

southern-scotland-bat-survey.jpg

To ensure that green energy generation is deployed in a sustainable way, we need to minimise the impacts of future wind farm developments on bats. This requires surveys and analyses that are able to deliver a robust understanding of large-scale patterns in species’ distributions and abundance.

The Southern Scotland Bat Survey demonstrated that extensive presence-absence survey data can be collected for bats across a large region (> 20,000 km²) of southern Scotland, using volunteer efforts, and supplemented with additional fieldworker contribution in remote areas.

Classifiers from the Acoustic Pipeline were used to process recordings from the project. The subsequent data was then analysed to quantify the impact of future wind farm development on bats, highlighting the top 1%, 5% and 10% of the area for bats.

• Read a summary of the peer-reviewed publication Large-scale citizen science improves assessment of risk posed by wind farms to bats in southern Scotland (Newson, S.E., Evans, H.E., Gillings, S., Jarret, D., Raynor, R., Wilson, M.W. 2017. Biological Conservation 215)

Public engagement and high-quality data collection – Norfolk Bat Survey

norfolk_bat_survey.png

The Norfolk Bat Survey was the first project to benefit from early versions of the Pipeline’s ultrasonic classifiers.

Using an equipment booking system and square sign-up map, volunteers across Norfolk borrowed bat recorders, recording over 2 million bat detections from 6,145 locations across the county.

As well as providing a novel engagement opportunity, the survey has generated high-quality data, which have been used in four peer-reviewed journal articles:

• Can citizen science provide a solution for bat-friendly planning? (Border, J.A., Gillings, S., Reynolds, T., Neeve, G. & Newson, S.E. 2022. Landscape & Urban Planning 223)
• Bats in urbanising landscapes: habitat selection and recommendations for a sustainable future (Gili, F., Newson, S.E., Gillings, S., Chamberlain, D.E. & Border, J.A. 2019. Biological Conservation 241)
• Predicting the likely impact of urbanisation on bat populations using citizen science data, a case study for Norfolk, UK (Border, J.A., Newson, S.E., White, D.C.J. & Gillings, S. 2017. Landscape and Urban Planning 162)
• A novel citizen science approach for large-scale standardised monitoring of bat activity and distribution, evaluated in eastern England (Newson, S.E., Evans, H.E. & Gillings, S. 2015. Biological Conservation 191)

Providing baseline data – Bailiwick Bat Survey

bailiwick_bat_survey.png

Starting in 2021 and working with a network of volunteer fieldworkers, the Bailiwick Bat Survey aims to provide extensive baseline data for bats for Guernsey, Alderney, Herm and Sark. The Survey involves the deployment of static acoustic bat detectors over a 7 month survey season.

In its first two seasons, the project resulted in the discovery of six new bat species for the islands. During 2022 alone, 622 different locations across the Bailiwick of Guernsey were surveyed, amounting to a total of 2,416 nights of recording effort across sites.

• Read the Bailiwick Bat Survey: 2022 Report >