Remember those old Windows screensavers? You know, the ones with the twisting, twirling, colour-changing shapes? Well, murmurations look sort of like that, except with birds – and way cooler.

Although you might not recognise the name, a murmuration is something you’ve likely seen before. The phenomenon happens when hundreds, often thousands, of birds fly together, suddenly and simultaneously changing direction.

This video, posted online by YouTube user Robin Sansom back in 2014, shows thousands of red knots (shorebirds in the sandpiper family) flocking together in a nature reserve in Norfolk, England. And unlike the black starlings murmurations you more typically see, this spectacle gets a boost of colour. 

Come breeding season, the heads and chests of these shorebirds turn reddish, while their winter attire is mottled grey on top, with a noticeably white belly. In the sunlight, those hues make for some hypnotising patterns as the swooping birds switch directions and the colour shifts from light to dark.

The murmurating swarm, which appears almost as one giant organism, relies on a few key rules. Rule number one? If the bird next to you moves, you move! Scientists are still working out exactly how this bird ballet works, but one thing is obvious: it's incredibly beautiful. 

According to the BBC, the migratory knots arrive in north Norfolk from Arctic Canada and Iceland each year for their winter roost, and their murmurating performance hinges on very specific weather and tidal conditions.  

"There are possibly just three or four mornings a year when they'll do this," says wildlife presenter Chris Packham.

h/t: Mother Nature Network 


Top header image: Cláudio Dias Timm, Flickr