Distribution and flight heights of Sandwich Terns Thalasseus sandvicensis during different behaviours near wind farms in the Netherlands

Abstract

ABSTRACT Flight heights and behaviour of 1460 Sandwich Terns Thalasseus sandvicensis in the Dutch North Sea were recorded with a laser range finder during ship-based surveys in 2020 and 2021. Over 87% of all Sandwich Terns were flying below 20 m, and fewer than 1.5% were recorded above 40 m, leading to a two-fold increase in the collision risk model estimates for the Borssele offshore wind farm in the Netherlands compared to the current standard flight height distributions.