A murmuration is the intricately choreographed movements of a large flock of starlings as they swoop through the sky. The phenomena appears like an undulating cloud, quickly shifting directions, density and shape as it traverses overhead. Due to a relatively warm winter in the Netherlands between 2014 and 2015, many starlings stayed in the country rather than migrating south. Filmmaker Jan van IJken captured one such air show in his short film The Art of Flying, which can be watched in full on his website.
via This Colossal