Quantifying the impact of avian influenza on the Northern Gannet colony of Bass Rock using ultra-high resolution UAV imagery and deep learning

Abstract

Since 2021, Highly Pathogenic Avian Influenza (HPAI) has caused significant bird mortality in the UK, mainly affecting aquatic bird species. The world’s largest northern gannet colony on Scotland’s Bass Rock experienced substantial losses due to the outbreak. To assess the impact of HPAI on the colony, this study applied a deep learning neural network on UAV RGB imagery from 2022 and 2023 to automatically detect and count live and dead gannets, providing population estimates for both years. The model was trained on the 2022 dataset and achieved a mAP of 37%. Application of the model predicted 18,220 live and 3,761 dead gannets for 2022, consistent with NatureScot’s manual count of 21,277 live and 4,285 dead gannets. For 2023, the model predicted 48,455 live and 43 dead gannets, pending manual count. This marks a promising start to the colony’s recovery with a population increase of 166%, and showcases the methodology’s potential for future monitoring of other gannet colonies and wildlife species.