Owls use their ears when they hunt. Sounds prey make – the footsteps of a vole on a forest floor, for instance -- are captured by ears that are asymmetrically placed on the bird's head. One ear is slightly offset from the other. Sounds thus arrive at different times in each ear. The difference is miniscule, but enough to allow the bird to triangulate the source. That information allows the owl to strike successfully without seeing its prey, at night or when the mouse or shrew or vole is beneath cover, like snow.

I was at the Raptor Center a couple of days ago to photograph the resident Boreal Owl. The bird is blind in one eye. It couldn't survive in the wild so it has become one of the birds used by the center in education programs. Gail Buhl, the center's education program manager, held the bird for me. We talked about the bird's hunting abilities as I took my photos. She mentioned that Boreal Owl ears are particularly asymmetrical.

In the Raptor Center lobby is a display of owl skulls, and drawers holding raptor wings, feathers, and feet. I stopped to look at the Boreal Owl skulls. It is easy to see what Gail was talking about. Boreal Owl ears are offset significantly. Each has its own distinct shape. The ear openings look little like one another.

The photo below shows the ears.