Last weekend, my husband and I found ourselves at dusk in a park we frequent in Sunol. We were procrastinating because it was Sunday night, the park was lovely and we didn’t want to go home yet. We stopped in a clearing because a few red-breasted robins were flitting around but as we stood there, the few became many and the many became hundreds.

The next thing we knew, the birds had started to form a murmuration, an undulating wave of birds that swooped and swarmed ahead of us. Where I come from, birds are a little more raucous so I was delighted to see this display for the first time.

Murmuration comes to the English language from the Medieval Latin murmuratio – to murmur – and has been with us since about 1350. So it predates YouTube. Though if YouTube did exist, and you’d been watching every one of the 243,261 days since you would still have 183 million days before you exhausted YouTube’s store of webcam confessionals and cat videos. On second thought, maybe skip the cat videos – the birds might not like them.

The most famous proponents of murmuration are English starlings, which have been known to form waves of hundreds of thousands. Science has been looking into this strange and wonderful behavior and has found – as is so often true with beautiful natural phenomena – there is a macabre reason for it. The birds, alerted to the presence of a predator such as a peregrine falcon or hawk, realize it is safer in a crowd so they bob and weave to confuse and avoid the diving raptor.

So how do they do it? An international team of aerospace engineers and computer modeling experts found that starlings were not communicating all together but sending messages to and from only their nearest neighbors. Seven of them, to be exact.

That magic number plus the speed and accuracy at which starlings can dart and dive convinced the scientists that starlings were acting as a “critical system,” which occurs throughout nature as a collection of things poised for near-instantaneous change. In fact, there are parallels in particle physics. Wired magazine has an explanation of how it works, and says the system transcends biology – determining the crystal structure and the makeup of an avalanche. If you can understand it, please explain it to me.

Even without the knowledge of what it means for particle physics, bird nerds have long appreciated the murmuration spectacle. Perhaps the murmur in its name should refer to our own noises of surprise and delight, wonder and joy.