What Makes Starlings Gather?

For starlings, there鈥檚 benefit in the bustle of a murmuration.

Humans are unquestionably captivated by the hypnotic gatherings of hundreds or thousands of starlings in pulsing murmurations (simply check the ). But the swirling avian bodies provide far more than our entertainment鈥攖hey likely help the birds survive. Scientists are trying to decode these phenomena to better understand what benefit birds reap from the morphing mass, and are finding that the mesmerizing displays may be as protective as they are gorgeous.

It鈥檚 widely accepted that murmurations offer safety by virtue of their sheer scale. For birds within the mass, the center likely represents the ultimate escape from predators on the fringe. Some researchers think it鈥檚 this that puts the murmuration in a state of permanent flux, as birds continuously fine-tune their flight to reach the safest possible position. This creates an unpredictably fluid body, devoid of a central point.

鈥淗iding鈥 in such a noticeable swathe may seem counterintuitive, but the gathering also means birds have hundreds of eyes watching out for predators, rather than just two: Research has shown murmurations can than solitary birds.

So what does the flock do when it spots a predator nearby? New research reveals that the that often pass through portions of the avian cloud may 鈥攂ut not in the way we might think.

Called 鈥渁gitation waves,鈥 the motions occur when a predator like a falcon gets too close to the crowd, triggering a fast moving ripple that travels at almost 44 feet per second across the mass and away from the offending bird. From afar the starlings appear to be moving closer together.

But using a program called Star Display to model these murmurations, from the University of Groningen realized the birds aren鈥檛 actually getting closer. They鈥檙e simply rotating to reveal the broad side of their wings. 鈥淭his exposes a larger area of the wing temporarily and this is seen by us as a dark band,鈥 Hemelrijk says. The angled bodies look momentarily like a solid mass and consequently, individual birds are tougher to pick out.

Just as it deceives us, this illusion might throw off predators, momentarily stunned by the change. 鈥淚t confuses the predator as to whom it should attack,鈥 Hemelrijk says.

In addition to safety, these large gatherings also offer , and a chance to feed collectively. Compared with solitary flight, it鈥檚 no wonder birds join in, inadvertently creating a spectacle for those of us below. 

Watch a murmuration: