A swarm of Pied Avocets (Recurvirostra avosetta). This image was made at the coast of The Waddenzee in the northern part of the Netherlands where they breed. In autumn these birds gather together. When they are disturbed by birds of pray they get in the air in a fast moving swarm. This behaviour makes it difficult for birds of pray to catch a victim. It is a migratory species and most winter in Africa or southern Asia. Nikon D850 + Nikkor 200-500mm (390mm). ISO 500, 1/2500 sec, f/7.1 (+ 1/3).