A bird in flight is a hypnotic sight, but the whorling, eddying patterns its wings take just don’t freeze-frame well. Using a 19th century technique, though, Spanish photographer Xavi Bou has figured out a way to take pictures of migrating birds while retaining the fluid sense of motion that gives them all their mystery, poetry, and grace.

In Ornitographies, Bou takes pictures of birds in a way that visualizes the patterns they make over time. “I always wanted to know what the shape of [a bird’s flight] would look like in the sky if our perception of time was different,” he says. His first attempt at doing so was essentially to use a long exposure to compress many seconds’ worth of motion into a single frame, but all Bou got for his trouble was a blur.

To solve the problem, Bou turned to chronophotography, a pre-cinema photography technique that combines multiple successive images in a row to study movement. A famous example of chronophotography is Eadweard Muybridge’s Horse in Motion, which proved that for a moment, a galloping horse’s four hooves are off the ground at the same time. The technique is still in use in the nascent field of photo visualization today.

Like Horse in Motion, Bou’s Ornitographies show the ripple-like beat of a bird’s wings, both flying singly or in a flock. Unlike Muybridge’s famous work, though, Bou uses Photoshop to stitch a hundred moments in time into a single image of a bird’s flight. When a bird is flying alone, chronophotography turns each bird into a severed Möbius strip of its own hypnotically beating wings. When in migration with others, Bou’s subjects resemble not so much birds in flight as shadow storms and hurricanes, streaking across the horizon.

Bou says that his lifelong love of birds was something instilled in him by his grandfather, during long walks on the delta of the Llobregat River outside of Barcelona, an area famous for its birdwatching. He tells me that what he likes most about birds is their diversity. It astonishes Bou, he says, that you can find birds almost everywhere on earth, with very specific adaptations made to that place.

“It’s a beautiful example of how complex nature is,” Bou says. “By documenting flight patterns, I hope to show the hidden beauty that can appear in nature when we try to look at it from a different point of view.”

[All Photos: Xavi Bou]