Raven Mad

Photograph by Henrik Nilsson, National Geographic Your Shot

A great gray owl sweeps its wing in Yellowstone National Park in this picture from Your Shot member Henrik Nilsson. "The owl was being harassed by a raven," Nilsson says. "If you look closely, you can see part of the nictitating membrane in the owl's left eye."

Nilsson, who visits Yellowstone at least once a year, had been driving one morning toward the Lamar Valley to look for wolves when he came across the owl in a small meadow. "It was sitting on top of one of the conifers—presumably looking for breakfast. At one