Sort sol

Sort sol, Danish for black sun, is a natural phenomenon in which very large numbers of migratory starlings gather over the marshlands of southwestern Denmark, particularly near Tonder and Ribe, as they pass between their European wintering grounds and Scandinavian breeding grounds each spring and autumn. In the hours following sunset, hundreds of thousands of birds, in some cases up to a million, form dense, shifting aerial formations before settling to roost, a coordinated display that has been compared to a choreographed dance. When threatened by a predator, the flock can also mount coordinated aerial maneuvers intended to disorient or overwhelm the attacking bird. This description is adapted from Wikipedia contributors under CC BY-SA 4.0; changes were made. https://creativecommons.org/licenses/by-sa/4.0/