Abstract
We present the application of the modelling framework developed under WP2 of the InTaS project funded by the Carbon Trust as part of the broader ORJIP initiative. The framework combines, for the first time, the statistical inference methods traditionally used independently for survey and telemetry data. It aims to accurately and precisely apportion the exposure of particular seabird colonies and age stages, to anthropogenic offshore disturbance. Common guillemots (Uria aalge) were identified as one of four priority species during the literature survey undertaken in WP1 of the same project. A large-scale proof of concept was agreed for the east coast of Scotland. Survey and adult telemetry data were collated for similar spatial and temporal extents. The locations and sizes of guillemot colonies were provided and used to guide the habitat modelling and apportionment algorithm. Model selection was carried out to explore combinations of nine environmental covariates that most parsimoniously explained the pooled telemetry and survey data sets. Using the best model, a comparison of survey-only, telemetryonly and joint survey-telemetry analyses confirmed the conclusions of simulation experiments from WP2 suggesting that the convergence and precision of joint analyses are superior to the single-data analyses. The covariates retained in the selected model indicated the importance of benthic variables (bathymetry, sediment) but also surface cues (thermal fronts and energy anomalies). Strong differences between juveniles and adults were inferred in terms of their attachment to their colonies, but not so much in terms of their attachment to regions closer to the coast. We present results on the spatial distribution of usage by different colonies and ages and the output of an illustrative calculation of apportionment for an exemplar off-shore region, along with a software tool that can use parameterisations from our modelling to perform the same apportioning calculation for any proposed area of potential offshore development.