Have you ever wondered how an owl can hunt for food in the dark? Welcome to Field Notes. I’m Rob MacDonald, a Wildlife Biologist with the Togiak National Wildlife Refuge.

Owls that hunt at night are impressive, silent hunters. At night, owls are able to locate even faint sounds with remarkable accuracy in low light levels. In total darkness, they can locate and capture prey by sound alone. The disk shape of the facial feathers of an owl acts as a reflector that channels sounds into its ears. Once a sound is heard, the owl turns towards it and can accurately pinpoint its location.

The cue as to which side the sound comes from is the difference in time it takes for the sound to reach each ear. When the sound is straight ahead, there is no difference in time that each ear hears the sound. Owls can also tell if the sound is above or below them. Due to the shape of their ears, if a sound comes from above the owl, the ears hear the noise louder than if the sound came from below the owl. If the sound is the same in both ears, that means the sound is at eye level.

The ears of an owl are linked to a specialized part of its brain that is sensitive to the combination of how loud the sound is and how long the sound is made for.

In addition to their extremely sensitive ears, owls have another trick that helps them in their night-time hunting. That trick is that owls may hold a territory in which they feed in each night. By feeding in the same area, they become very familiar with that area and get to know such things as the heights of favorite perches above the ground and where obstructions are that they need to avoid. This familiarity is essential for the ability of an owl to pounce on prey.

The owls hearing helps in the absence of light, but their intense knowledge of an area completes the whole package. For Field Notes, I’m Rob MacDonald.