Bart Kranstauber

Abstract Weather radars detect more than weather, they also continuously register the movements of billions of animals aloft in the lower atmosphere. This makes archived, unfiltered weather radar data a goldmine for biological monitoring purposes, providing coverage of the aerial habitat in a way no other method can.

1 INTRODUCTION The availability of movement data has increased exponentially in recent years (Kays et al., 2015; Nathan et al., 2022). Movement data are derived from various technologies, for example tracking devices, observation networks, re-sightings or tracking radars. The advances in technology have resulted in a proliferation of data, where single individual tracks can easily contain more than a million positional records.

1 INTRODUCTION As the world is transitioning towards sustainable energy production to meet climate targets, the airspace is bound to become riskier for flying organisms (Davy et al., 2017) due to increased wind energy production. In many countries, the expansion of wind turbines is concentrated offshore (Leung & Yang, 2012). These turbines pose a risk for migratory birds through collisions (Marques et al., 2014), habitat change and barrier effects (Drewitt & Langston, 2006).