From: Birds of Prey - Raptor Bird Calls and Ringtones »

The haunting call of this owl can be found in the forests of Alaska, Canada and northern Eurasia. Sound is its most important tool in hunting, and its ear openings are asymmetrical -- one ear is higher on its head than the other one. All the better to hear you with! The boreal owl's beautiful call has the mystery of the deep forests making it a great ringtone.