Owl Wing Feather Adaptations

It turns out that cottontail bunnies have more to worry about in the neighborhood than just hawks and coyotes.

As my husband and I were walking the dogs this morning, we found a Great Horned Owl wing feather lying next to the sidewalk. This stealthy hunter takes birds, skunks, mice — and rabbits.

Great Horned Owl wing feather. It probably dropped out because it was a bit worse for wear, and needed to be replaced.

And owls do so silently. The tailing edge of their wing feathers are frayed, preventing the air from generating noise-producing turbulence as it passes over and under the wing.

The trailing edge of the feather, an the bottom of the picture, has evolved to be frayed to keep the air from popping when the owl beats its wings.

But scientists have recently discovered another adaptation on feathers that helps owls keep quiet as they fly — a comb-like set of barbules on the leading edge of the feathers. These small structures “break up the turbulent air that typically creates a swooshing sound. Those smaller streams of air are further dampened by a velvety texture unique to owl feathers and by a soft fringe on a wing’s trailing edge. These structures together streamline the air flow and absorb the sound produced.” (https://www.audubon.org/news/the-silent-flight-owls-explained)

The “comb” on the leading edge of the feather helps to disrupt the turbulence, and make owl flight even quieter.

After whipping out my trusty camera and snapping these photos, I left the feathers by the sidewalk. Under the Migratory Bird Treaty, it is illegal to collect any native birds or their feathers for any reason.

Great Horned Owls Laying Eggs

I got up to let the dogs out around 4:00 this morning. While I was standing at the door waiting for them to finish, I heard Great Horned Owls hooting back and forth.

Great Horned Owls are laying their eggs now so their young will have hatched by the time prey like rabbits and mice are making their forays out of their nests.

Although Great Horned Owls normally hunt at night, every once in a while they are out in the day.

Broomfield CO owl

To see well at night, owls have very large eyes. In fact, owl eyes are so large that they are fixed in their sockets. This owl has turned it’s head completely around to see what’s happening behind it. Courtesy Randy Law

These large predators have the biggest range of any owl in North America, from the arctic tundra to southern deserts to semi-tropical forests, although they hunt better in semi-open areas. Their territory certainly includes my suburb in the foothills.

Owl feather depth_edited-2

Look at how far into the owl’s feathers the handler can put his finger! No wonder they can nest in the arctic. This bird is captive because its other wing is broken, and it can no longer hunt for itself.