Airflow modelling predicts seabird breeding habitat across islands

• Main Authors: Lempidakis, Emmanouil, Ross, Andrew N, Börger, Luca, Shepard, Emily L C
• Format: Other/Unknown Material
• Language: unknown
• Published: Authorea, Inc. 2021
• Subjects: Uria aalge; uria
• Online Access: http://dx.doi.org/10.22541/au.161108590.03726758/v1

Wind is a fundamental driver of the distribution and energy expenditure of birds at sea. Wind can also influence mortality at the nest. Yet airflows have never been fully integrated into models of breeding habitat selection. We use computational fluid dynamics to provide the first assessment of whether and how airflows predict the distribution of seabird colonies, taking common guillemots ( Uria aalge ) breeding on Skomer island as our study system. We reveal that air pressure predicts occupancy, demonstrating the importance of exposure (rather than wind speed) in habitat selection. Our simple model with pressure and slope correctly identified 80% of the largest colonies and 93% of avoided sites. While previous approaches have not predicted space use in novel sites, our model predicted 73% of the largest colonies on a neighbouring island. This suggests generality in the mechanisms linking airflows and breeding distributions, and highlights a novel route by which seabirds may be affected by global change.