Barcelona photographer Xavi Bou developed a love for birds as a child, and he often wondered what it would be like to see their patterns of flight, just as we can see the tracks of wildlife. He pioneered a process in which he films birds in flight and then extracts still images from the video and layers them on top of one another. These “ornitographies,” as Bou calls them, are his way of “making visible the invisible.” Pictured here: barn swallows over Jackson Lake, Wyoming. 

This article appeared in the September/October 2020 edition with the headline "Kiss the Sky."