FIGURE 10-17 Hunting by Ear Left: In the dark, a barn owl aligns its talons with the body axis of the mouse it is about to catch. Center: The owl’s facial ruff collects and funnels sound waves into ear canal openings through tightly feathered troughs above and below the eyes. The owl’s left ear is more sensitive to sound waves from the left and below because the ear canal is higher on the left side and the trough is tilted down. The right-side ear canal is lower and the trough tilts up, making the right ear more sensitive to sound waves from the right and above. Right: The boreal owl’s asymmetric skull produces a similar auditory asymmetry. Information from E. I. Knudsen (1981). The hearing of the barn owl. Scientific American, 245(6), p. 115.

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