How Can Owls Fly So Quietly?

Owls' ability to fly almost silently gives them an air of mystery, but the science is in their wings and feathers. Learn how they do it in this episode of BrainStuff, based on this article: https://animals.howstuffworks.com/birds/owl-fly-silently.htm/printable

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Episode Transcript

Speaker 1 (00:01):
Welcome to Brainstuff, a production of iHeartRadio, Hey brain Stuff
Lauren Vogelbaum. Here a few creatures are surrounded by as
much myth and mystery as the owl. Sometimes they're marked
as ominous, portance of death and hardship, sometimes symbols of
wisdom and prudence. From ancient texts to modern fantasy movies,

(00:25):
owls have captivated us with their fierce hunting capabilities, striking appearance,
nocturnal habits, and near silent power of flight across the globe.
Legends developed around them. Some Hindu cultures associate the owl
with the goddess Lakshmi and consider it a symbol of
luck and prosperity. The Greek goddess of wisdom Athena, offered

(00:48):
special protection to the owl as her favorite feathered friend.
As a result, many owls lived the acropolis. The stealthy
owl was also seen as protector of Greek armies. Owl
imagery often decorated warrior's shields, and some said that seeing
an owl before a battle signaled a triumph to come.
The Dakota Hidatsa have also viewed the owl as protectors

(01:10):
to warriors, but others saw owls as predictors of death.
But lore has it that the hoot of an owl
announced the death of Julius Caesar, and several Southwestern American
native cultures associate owls with ill omens and their calls
with impending death. Today, let's look at one of the
factors that makes owls so interesting their silent flight. While

(01:34):
it adds to owl's mystique, this superpower of sorts serves
a very practical purpose. It helps them sneak up on
their prey. It's the design of owl's wings and feathers
that allows them to fly in almost absolute silence. The
two things that cause the most noise when birds fly
are the flapping of their wings and the noise of

(01:55):
turbulence as they move through the air. That is the
sound of air flowing chaoo over and around their wings.
Owls have broad wings with large surface areas that help
them glide through the air without flapping very much. Less
flapping makes less noise, and the owl's feathers work to
reduce turbulence. An owl's primary feathers, which are the long

(02:19):
ones forming the tip of the wing, are serrated like
a comb on their leading edge that's the edge facing
forward as they fly. This comb like design breaks down
turbulence into smaller currents called microturbulences. Then, the opposite trailing
edge of each primary feather has a tattered fringe shape

(02:39):
that muffles the sound of air flowing over the wing
and shifts the angle at which the air flows. These
soft feathers allow air to pass through, which helps eliminate noise.
Some reachers think that as the owl flies, these feathers
may also shift sound waves created by the owl's wing
to a higher frequency that prey can't hear. The owl's

(03:03):
secondary feathers, which are the shorter ones that run from
the midwing to the shoulder, are made up of soft
fringes that reduce turbulence behind the wings. The trailing feathers
on the back end of the wing are also tattered
in shape, and the rest of the wing and legs
are covered in short, downy feathers. As the owl flies,
the trailing fringe in tattered feathers breaks sound waves over

(03:25):
the wings as the air flows over them. The downy
feathers absorb any remaining noise created in flight that's above
two thousand herts, thus eliminating most sounds that owl's potential
prey can hear, So the secret is in the wings.
But does this noise reducing design have a place in
your next airplane flight? Engineers are always in search of

(03:49):
ways to improve aircraft technology, and nature inspires the greatest innovations.
Sometimes called biomimicry. Researchers have looked to the design of
owl's wings to reduce use the noise created by aircraft
while keeping takeoffs energy efficient. For example, some proposed to
the possibility of creating retractable fringe to mirror owls trailing feathers,

(04:12):
helping reduce turbulence and noise, and others think that applying
a velvety coating on landing gear will absorb noise just
as the downy feathers do on an owl's legs. Airports
like O'Hare and Heathrow have strict noise restrictions on aircraft's takeoff.
If engineers find a way to reduce noise, more flights

(04:33):
could take off every day, and revenue could increase. For
an industry struggling with fuel costs and other problems, the
wise old owl may provide some solutions. Today's episode is
based on the article how can Owls Fly? Silently on
howstuff Works dot com, written by Sarah Winkler. Brain Stuff

(04:54):
is production of iHeartRadio in partnership with house toffwork dot
com and is produced by Tyler Klang and Ramsey Young.
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