Quiet Wings

 

Snowy Owl (Bubo scandiacus) Boundary Bay, British Columbia, Canada.  December.

Snowy Owl (Bubo scandiacus) Boundary Bay, British Columbia, Canada. December.

Night-hunting owls find their food using a keen sense of hearing. But they also rely on the stealth that comes from special adaptations to reduce flight noise. The fluffy feathers that cover the underside of the owl’s body and its legs and feet appear to act as sound dampers. The wings also have several important modifications.

 

Noise reducing modifications to the wing of a Barn Owl compared to a pigeon wing. Adapted from: Bachmann, T. et al. Morphometric characterisation of wing feathers of the barn owl (Tyto alba pratincola) and the pigeon (Columba livia). Front Zool. 2007 Nov 21;4:23.

Noise reducing modifications to the wing of a Barn Owl compared to a pigeon wing. Adapted from: Bachmann, T. et al. Morphometric characterisation of wing feathers of the barn owl (Tyto alba pratincola) and the pigeon (Columba livia). Front Zool. 2007 Nov 21;4:23.

In the illustration above, compare the front (leading) edge of barn owl and pigeon primary feathers shown below. The razor-like leading edge of the pigeon’s wing is very different from the spiny front edge of the owl wing. These spines are noise-reducers that are most effective when the bird is in a steep dive toward its prey. The back (trailing) edge of the owl feather is also fluffy to reduce noise.

Aircraft designers are anxious to learn lessons from owls. In a “biomimetic” approach, designers assume that evolution has already solved a problem such as flight noise reduction. They then try to copy the solution when designing machines. So quiet owls may lead to quieter airplanes!

LEARN MORE ABOUT QUIET WINGS

KIDS QUESTION: In the museum exhibit, we asked: Why do owls need to be quiet when they fly?

The answer is: To surprise their prey
It is also possible the wing noise would interfere with the owl’s acute sense of hearing so that it would not be able to listen as well for the sounds of prey.