Validating the effectiveness of time-lapse photography for the population monitoring of a colonial seabird

Abstract

**Abstract:** The global Black-legged Kittiwake (Rissa tridactyla) population is declining rapidly in NW Europe, and so effective productivity monitoring is essential to understand such concerning long-term population trends. Current UK Seabird Monitoring Programme fieldworker methods are sufficient but labour-intensive, preclude detailed phenology data, and are not always feasible in remote locations. Time-lapse cameras have the potential to overcome these challenges, but the volume of images can rapidly exceed researchers' visual processing capabilities as study size increases. Using volunteer citizen scientists to analyse photographs and training computer algorithms to recognise birds represent two possible image processing methods. Before algorithm-based methods can be deployed, computer analysis of time-lapse photographs must be validated against fieldworker observations, and image analysis by citizen scientists must be validated against skilled image analysts with field experience. Using camera and 'human' monitoring data from sites in the UK (Skomer Island) and Arctic Circle, this study aims firstly to determine whether time-lapse photography can measure Kittiwake nesting success and phenology, and secondly to validate computer analysis vs fieldworker methods, and citizen scientists vs skilled image analysts. Validating time-lapse photography to measure breeding success and phenology could unlock the potential to better understand the causes of global Black-legged Kittiwake decline. **Authors:** Alice Edney¹, Matt Wood², Tom Hart¹, Mark Jessopp³, Alexa Piggott⁴ ¹University of Oxford, ²University of Gloucestershire, ³University College Cork, ⁴Wildlife Trust of South and West Wales