|If an owl were to fly by you, you probably wouldn't hear it coming. They fly much more silently than other birds.
Why is that?
The answer is in the feathers that make up the wing. When a bird flies, air moves over the wings, which creates turbulence. This is what’s responsible for the noise. However, owls have serrated edges on both of the front and back edge of their wings, which breaks up the air into microturbulences. This reduces the noise.1 Their feathers also have a velvet-like texture that helps to reduce the noise even more.2&3
There are two hypotheses as to why owls have adapted to fly so silently compared to other birds. The first is that flying silently helps them capture prey by making sure the prey doesn’t know they’re coming. The second is that because owls rely on hearing to capture prey they can’t see, noisy flying would interfere with their ability to locate prey.3
Evidence has been found to support both hypotheses. A study found that owls who hunted prey that had a good sense of hearing, like small rodents, have a wider serration on their wings, which enables them to fly more quietly. Meanwhile, owls that hunt prey that don’t hear as well, like insects or fish, or those who hunt during the daytime, had smaller serrations and so made more noise while flying.3
Their silent flight is what helps them become such good hunters. Check out more adaptations they have as the perfect hunter here!