Video shows the shape of a flock of starlings evading a hawk

Xai Bou is a photographer who takes photos not of birds, but of the movements of birds — the shapes they trace as they move through the sky.

A while ago he did a project called Ornithographies, in which he'd take rapid-fire photos — several times a second — and stitch them together to make a photo that shows a bird's complex flight path. (You can see those remarkable pix at his site here.)

Recently he released "Murmurations", a video that uses this technique to illustrate a flock of starlings evading a hawk. Again, he took thousands of split-second images, then used them to produce a moving image.

It's like a mesmerizing form of dataviz — the action of the birds abstracted into vectors of pure movement.

As Bou describes it to Audobon:

"What happens is, if in this moment a hawk appears to attack them, it's when they do this dance," he says. "The hawk is like carving this ephemeral sculpture that's in the air." As with the still images, Bou knit multiple series of photographs together to create an animation. He estimates that every day of filming requires two weeks of post-production work; for Murmurations, he also enlisted the help of a film editor. The final product, which was filmed in southern Catalonia, was then set to ethereal music. [snip]

The idea for Ornithographies began with a paw print he saw while hiking in the Mediterranean forests of Catalonia. "I thought to myself, what kind of tracks would leave the birds in the sky?" Bou says. "I imagined these shapes." [snip]

As Bou began developing the project, he didn't want people's analytical brains to kick in when they saw his work. He didn't want a viewer thinking about the tilt of the wings or the shape of the feathers at a particular moment, as one might while looking at a series of photographs by Eadweard Muybridge, one of the original chronophotographers. "I don't want to see the 'bird, bird, bird'," Bou explains. He found that by overlapping photos taken in quick succession, you lose the shape of the bird, revealing instead a "complete new organic shape."