Murmurations can comprise up to hundreds of thousands of flying starlings, though few are quite as dramatic as this one. Photojournalist James Crombie captured it over Lough Ennell, a lake near
Mullingar in Ireland, after more than 50 visits in which he took hundreds of shots.
Starlings are thought to form murmurations to protect themselves from predators, such as peregrine falcons, since it is much harder to single out an individual among such large numbers.
The birds can coordinate themselves because they respond so quickly to their neighbours. No single starling leads the swarm. Instead, each individual reacts as its neighbour changes direction or speed. We now know that starlings do this in groups of around seven: the movements of each small unit rapidly scale up to the entire murmuration, resulting in the shape- shifting masses.