Owls come in all shapes and sizes from the majestic Great Greys to the tiny Elfs. There are about 200 different owl species in the world, and one thing they all have in common is their flat face.
Owls have flat faces because it helps them to hear better. Their flat face or facial disk and some of their feathers capture the sound waves made by prey and direct them to the owl’s ears.
The Anatomy of an Owl’s Face
An owl’s flat face is also called the facial disc and it refers to how the owl’s feathers are positioned on its face and frame its facial features.
Their face has a concaved shape that allows sound waves coming towards the owl to be caught.
The owl’s ears are located on either side of its head behind the eyes. The eyes and ears are both asymmetrical.
Feathers are found around the eyes and spread over the facial disc all the way to the ear canals.
These feathers play an essential role in directing sound waves into the owl’s ears.
Owls can adjust their feathers so they can catch sounds more efficiently.
And they are also able to adjust their facial disk feathers, changing the shape of their facial disk to channel more sound into one ear than the other.
The sound the owl hears can be heard differently, depending on where it’s coming from.
The owl’s flat face allows its brain to pick up sounds from different ranges, which means that the owl can hunt prey close by and far away.
It can also hear prey sounds through various environmental factors, weather conditions, and landscapes like bushes, trees, thick vegetation, snow, and grassland.
Owls rely heavily on their hearing to hunt, which is why they are nocturnal birds. They don’t necessarily need to see their prey, so hunting in the dark works well.
Why Are Owls’ Eyes Unique?
Owls’ eyes are unique because unlike most prey animals whose eyes are located on the sides of their heads, owls’ eyes are on the front, forward-facing.
Eyes that point towards the front allow them to spot danger coming their way.
It is also a great hunting adaptation as it allows them to track the movement of prey.
A unique feature of owls is the translucent third eyelids.
The membranes that make them translucent protect the owl’s eyes from dust or debris when swooping to attack prey.
Like humans, owls’ fields of vision overlap and have binocular vision. This vision allows them to track the distance of their prey so that they can time when they should attack.
Two features that are common to the owl’s eyes are:
- The large size.
- The owl’s ability to see at night.
Why Owls Have Large Eyes
Owls have large eyes so that they can see efficiently in the dark.
Their eyes are so prominent compared to the rest of their bodies that they can weigh between 1% – 5% of the owl’s total body weight.
While their eyes appear round, they are actually elongated tubes.
Owls have a bony structure in their skull called sclerotic rings to support their massive eyes and hold them in place.
These rings are rigid and prevent the owl from rolling or moving its eyes, which are fixed in place and can only look forward.
Since owls cannot move their eyes, they have adapted to be able to look on either side by moving their neck.
They are the only animals that can turn their neck 270 degrees in each direction and move it up and down at ninety degrees.
This means that they can see almost everything around them just by rotating their necks.
Most owls are far-sighted, though, and have difficulty focusing on anything close to them.
To compensate for this, they use the bristles on their beaks that are very sensitive to pick up on things close to them.
Night Vision
Owls hunt at night, so they must have superior night vision.
Their large eyes let them see in the dark by allowing them to take in sufficient light, even when the sun goes down.
To help take in more light, their pupils can dilate extremely wide.
The owl has two different types of light-sensitive cells in its retina.
They have rods that detect movement and light and cones that can see different colors.
Owls have about 30 rods for every cone, so they are able to see movement a lot easier than humans at night.
Another distinguishing feature is that an owl’s eyes can reflect light with a layer behind the owl’s retina called the tapetum lucidum.
This can catch any light that passes through the retina and throws it back to the rods.
Other Ways Owls Have Adapted To Be Predators
Apart from a face that complements its hearing and excellent night vision, owls have adapted in other ways to be predatory. These adaptions include:
- The color of their feathers.
- Flying silently.
- Strong, sharp talons.
The color of the owl’s feather usually blends into its environment, camouflaging it from its prey.
Grassland owls typically have light brown feathers, snowy owls have white feathers, and flammulated owls’ feathers are dark green.
These colors help the owls blend into their environment, and the feathers keep them warm.
With most birds, you can hear them take off and land by the sounds they make and the rustling and flapping of their feathers.
In contrast, owls have adapted to making virtually no sound when they fly.
There are serrated feathers on the edges of an owl’s wing, which help stabilize the owl and reduce the number of sounds it makes when it is flying.
At the back of the wings are tatty feathers that absorb sounds the wings make as they flap, making it difficult for prey to hear.
Lastly, the owl uses its talons and feet as weapons. Owls use their long, strong, and sharp talons to catch and kill their prey.