Heard of a plague of grasshoppers? Well, there are enough birds (I’m assuming they’re starlings) in the sky in this video taken in California to be a plague of starlings. But what is even more intriguing is the sight they make when they fly around. It’s a huge number of birds making changing formations in the sky, swirling around and ballooning out making various elliptical shapes. There are many groups of them, and as they fly around it makes undulating black patterns as all the birds move to one spot or another.

For example, at one point, there are four sections of birds: a neatly-contained elliptical shape at the top, two smaller groups underneath, and a more scattered-apart group coming in from the bottom. The bottom group moves upward and forms a bulging “head”, compresses down into a dense mass and then puffs outward and dissipates. The top section of birds flies upward, condensing as it goes into a small black blob. Meanwhile one of the smaller, side-groups pushes a narrow arm into the other side group, which spreads out, swirls downward, thickens as it moves up, rushes forward and collides (or seems to; they’re really two distinct layers) with the small dark blob, which is so thick with birds it looks black. The group thins on one side as some birds go behind the dense blob, which seems to fall apart and collect again, undulating with the added birds; meanwhile on the other side, it swells out. That was only a few seconds worth; at another point there are even more groups. Anyway, you can go see for yourself!

Around the middle of the video they seem to disappear, but keep watching; they come back in an even more impressive display.

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