The bird world is full of majestic hunters like eagles, hawks, and falcons, but when the sun sets, one group of avian predators reigns supreme.
Owls have many adaptations that make them excellent at stalking prey at night, including specialized wing feathers for silent flight, asymmetrical ears for triangulating the locations of sounds made by their prey, and legs tipped with deadly talons. Overall, though, theres one characteristic in particular that birdwatchers find captivating: owls eyes.
Below, weve rounded up details on all the features that make owl eyes so amazing. We hope youll find them just as astounding and “eye-opening” as we do!
Owls distinctive “wise” appearance comes from the intense stare resulting from the position of their piercing eyes, both of which are located facing forward on the front of the head, like our own. This arrangement is actually an adaptation for tracking the movements of potential prey.
Where their two eyes fields of view overlap, owls have 3-D or “binocular” vision, a trait they share with humans and the many other predatory animals. This provides them with acute depth perception that allows them to gauge distance to perfectly time their attacks. In fact, owls have the most forward-facing eyes of any group of birds!
Prey animals, on the other hand, tend to have eyes situated on the sides of their heads. This arrangement sacrifices depth perception for a wider field of view that gives them a better chance of spotting incoming danger.
Although humans and owls share binocular vision, owls are equipped with an important feature that we lack: nictitating membranes. These translucent “third eyelids” close horizontally from the inside corner of owl eyes and are there to protect them from debris when the owl swoops in for the attack.
Forward-facing eyes and extra eyelids arent the only optical advantages that owls possess. They have one important habit that sets them apart from other avian predators: Most of them hunt at night. And that means they need to be really, really good at seeing in the dark.
Owls enormous eyes help them take in enough light to see, even after the sun sets. Owl eyes make up as much as 5 percent of these birds total body weight. That may not sound like a lot, but for comparison, your eyeballs are about 0.0003 percent of your total weight.
In addition to their out-sized eyes, owl pupils dilate extremely wide to let as much light as possible hit the light-sensitive retina at the back of the eye.
Like us, owls have two different types of light-sensitive cells in their retinas — rods (which detect light and movement) and cones (which distinguish color). Humans have about 20 rods for every cone, but in owls that ratio is more like 30 to one, making them exceptionally good at picking up movement even when its dark.
If youve ever been out at night and seen owl eyes shining back from your flashlight beam, you no doubt noticed their reflective power, which is yet another way that owls enhance their night vision.
Behind an owl eyes rod-packed retina is another layer called the tapetum lucidum, which catches any light that may have passed through the retina and bounces it back to those sensitive rods. All of these adaptations add up: Some owl eyes may be as much as 100 times more sensitive in low light than ours. The one downside is that owls tend to be farsighted and experience difficulty focusing on objects at close range, but sensitive bristles around their beaks make up for this a bit, giving them another way to sense objects close to their faces.
Theres just one problem: fitting those gigantic eyes into the relatively small skull of a bird.
Owls eyeballs arent really balls at all. Theyre more elongated than human eyes — yet another special adaptation to help them work more efficiently in low light. Owls have special bony structures called sclerotic rings to support these huge eye structures and hold them in place. These rigid rings prevent owls from being able to move their eyes — you can roll your eyes to the left or right while holding your head still, but an owls eyes are fixed in place, pointing straight ahead.
To compensate, owls have evolved their famous ability to turn their necks incredibly far in either direction. They cant literally turn their heads all the way around, but they can rotate them 270 degrees (three quarters of a full circle) in either direction, plus 90 degrees up and down.
Owl eyes are so big that in some species, you can actually see the base of their eyes by peeking into their ears (check out this article from 2018 for some amazing photos). Of course, even owls cant see in total darkness, but some species, such as Barn Owls, can hunt by sound alone, able to catch mice even in a sealed, pitch-black environment.
There is a common misconception that because owls have excellent night vision, that means theyre blind in daylight. Not true! Owl pupils can contract in bright light just like ours do. They can dilate and contract the pupil of each eye independently, giving them an amazing amount of control over just how much light hits the retina in each eye.
In fact, some owl species are more active during the day than at night — and eye color can be a good indicator as to which type of owl youre seeing. Although there are many exceptions to this rule, a 2018 study found that, overall, nocturnal owls are more likely to have dark eyes (like the Barred Owl), while owls active in daytime or at dusk are more likely to have orange or yellow eyes (like the Snowy Owl).
In less than a single human lifetime, 2.9 billion breeding adult birds have been lost from the United States and Canada, across every ecosystem. This includes familiar birds: The Dark-eyed Junco has lost an incredible 175 million individuals from its population. The White-throated Sparrow has lost 93 million.
Owls may be able to avoid detection during the day, but they cannot escape the same threats faced by other birds. Scientists have identified that habitat loss is the biggest overall driver of bird declines. Habitat loss occurs when land is converted for agriculture, development, resource extraction, and other uses. Habitat degradation is a second cause of losses. In this case, habitat doesnt disappear outright but becomes less able to support birds, such as when habitat is fragmented or altered by invasive plants, or when water quality is compromised.
Climate change is expected to exacerbate these threats, and also to create new challenges, for example, by changing habitat distributions and shifting the timing of peak food supplies for birds.
American Bird Conservancy and our Joint Venture partners have improved conservation management on 6.4 million acres of U.S. bird habitat — an area larger than the state of Maryland — over the last ten years. This is a monumental undertaking, requiring the support of many, and you can help by making a gift today.
Policies enacted by Congress and federal agencies, such as the U.S. Fish and Wildlife Service, have a huge impact on Americas birds. You can help shape these rules for the better by telling lawmakers to prioritize birds, bird habitat, and bird-friendly measures. To get started, visit ABCs Action Center.
Finally, dont overlook the impact you can have at home. Living a bird-friendly life can have an immediate impact on owls and the other birds around you. Doing so can be as easy as adding native plants to your garden, avoiding pesticides, and keeping cats indoors. To learn more, visit our Bird-Friendly Life page.
Your contribution will be matched dollar-for-dollar. Act by December 31!
There are many magnificent hunters in the bird kingdom, such as eagles, hawks, and falcons, but at dusk one group of avian predators takes over.
Owls are skilled at nighttime stalking prey due to a variety of adaptations, such as their asymmetrical ears for locating their prey’s sounds, their specialized wing feathers for silent flight, and their legs equipped with sharp talons. Overall, though, owls’ eyes are one feature in particular that fascinates birdwatchers.
We’ve compiled information on every characteristic that makes owl eyes so remarkable below. We sincerely hope you will find them as “eye-opening” and astounding as we do!
Since both of an owl’s piercing eyes are positioned forward on the front of the head, just like our own, their intense stare gives them a unique “wise” appearance. Actually, this configuration is an adaptation for monitoring the whereabouts of possible prey.
Owls, like many other predatory animals, have 3-D or “binocular” vision where the fields of vision of their two eyes overlap. Because of this, they have keen depth perception, which enables them to judge distance and time their attacks precisely. Indeed, among all bird species, owls have the most forward-facing eyes!
On the other hand, the eyes of prey animals are typically located on the sides of their heads. With this configuration, depth perception is compromised in favor of a broader field of view, which increases the likelihood of identifying approaching danger.
Despite having binocular vision in common with humans, owls possess a crucial characteristic that humans do not have: nictitating membranes. When the owl dives in for the kill, these translucent “third eyelids” that close horizontally from the inside corner of the eyes shield the eyes from flying debris.
Having extra eyelids and forward-facing eyes aren’t the only optical advantages of owls. They differ from other avian predators in one significant way: the majority of them hunt at night. That implies that they must possess exceptional night vision.
Owls can see well even after the sun sets thanks to their large eyes. Up to 5% of the weight of these birds is made up of their eyes. That might not seem like much, but to put it in perspective, your eyeballs are roughly 0. 0003 percent of your total weight.
Owls have large eyes and their pupils enlarge greatly to allow maximum light to reach the light-sensitive retina located at the rear of the eye.
Similar to humans, owls’ retinas contain two distinct types of light-sensitive cells: rods, which sense movement and light, and cones, which detect color. Unlike humans, who have roughly 20 rods for every cone, owls have more than 30 rods, which allows them to detect movement even in the dark.
One more way owls improve their night vision is through their reflective power, which you have probably noticed if you have ever seen owl eyes shining back from your flashlight beam while you are out at night.
The tapetum lucidum, a layer located behind the rod-packed retina of an owl’s eye, is responsible for capturing any light that may have penetrated the retina and reflecting it back to the rods. The cumulative effect of these adaptations is that some owls’ eyes may be up to 100 times more sensitive to low light than human eyes. The only drawback is that owls have trouble focusing on close objects because they are farsighted, but this is somewhat offset by the sensitive bristles around their beaks, which provide them with an additional sense of objects near their faces.
The only issue is trying to fit those enormous eyes into a bird’s comparatively small skull.
Owls eyeballs arent really balls at all. They have an additional unique adaptation that makes them longer than human eyes, which helps them function better in low light. Owls’ massive eye structures are supported and held in place by unique bony structures known as sclerotic rings. An owl’s eyes are fixed in place, pointing straight ahead, unlike yours, which can roll to the left or right while keeping your head motionless due to these stiff rings.
Owls have developed their renowned ability to twist their necks incredibly far in either direction as a form of compensation. They can rotate their heads 270 degrees, or three quarters of a full circle, in either direction, plus 90 degrees up and down. However, they cannot actually turn their heads completely around.
Owl eyes are so big that in some species, you can actually see the base of their eyes by peeking into their ears (check out this article from 2018 for some amazing photos). Of course, even owls cant see in total darkness, but some species, such as Barn Owls, can hunt by sound alone, able to catch mice even in a sealed, pitch-black environment.
There is a widespread misperception that owls are blind during the daytime because of their superior night vision. False! Just like human pupils, owl pupils can contract in bright light. They have remarkable control over the amount of light that reaches each eye’s retina thanks to their ability to independently dilate and contract each pupil.
Certain owl species are actually more active during the day than at night, and you can tell what kind of owl you’re seeing by looking at its eye color. While there are plenty of exceptions to this general rule, a 2018 study discovered that owls that are active during the day or at dusk are more likely to have orange or yellow eyes, whereas nocturnal owls—like the Barred Owl—are more likely to have dark eyes.
In less than a single human lifetime, 2. In every ecosystem, 9 billion breeding adult birds have vanished from the United States and Canada. This includes well-known birds: the population of the Dark-eyed Junco has dropped by an astounding 175 million individuals. The White-throated Sparrow has lost 93 million.
Owls are vulnerable to the same threats as other birds, even though they can evade detection during the day. Researchers have determined that the primary cause of bird declines overall is habitat loss. When land is used for development, resource extraction, agriculture, or other purposes, habitat is lost. Habitat degradation is a second cause of losses. In this instance, habitat doesn’t completely vanish but instead loses its ability to support birds due to factors like invasive plant species, habitat fragmentation, and declining water quality.
It is anticipated that climate change will intensify these risks as well as bring forth new difficulties, such as altering the distribution of habitats and delaying the period when bird populations reach their peak.
We can all contribute to the preservation of owls and other birds.
With our joint venture partners, American Bird Conservancy, we have enhanced conservation management on six 4 million acres of U. S. over the past ten years, bird habitat—an area bigger than the state of Maryland—has This is a huge project that needs everyone’s support. You can contribute by giving today.
Legislation passed by Congress and federal organizations, including the U S. The US Fish and Wildlife Service significantly affects the country’s birdlife. By requesting that lawmakers give priority to protecting birds, their habitat, and bird-friendly policies, you can influence these regulations for the better. To get started, visit ABCs Action Center.
Finally, dont overlook the impact you can have at home. Owls and other nearby birds can benefit immediately from leading a bird-friendly lifestyle. Adding native plants to your garden, avoiding pesticides, and keeping cats indoors can all help you achieve this. To learn more, visit our Bird-Friendly Life page.
| Rebecca Heisman is a science writer based in eastern Washington. Her first book, which tells the scientific backstory of how we know what we know about bird migration, will be out in spring 2022. |
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I’d like to know more about birds’ vision. I’m particularly curious about how well they see at night. We had a nest by our back door this summer. Occasionally, we would use that door at night without remembering, startling the mother bird and sending it flying into the darkness. I was concerned that in the dark, she would find her way back to the nest. Is that a problem? –Carol, East Hartford, CT.
Cones are excellent color detectors, but their performance diminishes at night. Owls possess a comparatively small number of cones, but they also have additional rods that are sensitive to low light. Owls’ remarkable night vision is made possible by their profusion of rods, but their lack of cones suggests that they are most likely colorblind. Although colorblindness may seem like a bad thing, owls don’t mind. To impress their mates, males don’t need to grow ostentatious feathers. Additionally, by not having to purchase red roses for Valentine’s Day, they save a ton of money every year. Any color roses will do.
To avoid making this column sound like a biology lesson from middle school, remember that eyes are made up of rods and cones. Cones are essential for seeing objects in color, and birds have a lot of them in their eyes. Because of this, birds have exceptional color vision and become ardent supporters of the iPhone’s Retina Display. Why is color vision important for birds? Apart from making them happy with their iPhone, color vision surely helps birds find food, particularly when determining which berries are ripe or which flowers have the most nectar. And then there’s the whole mating thing. A lot of birds, especially the males, use their colorful plumage to entice a mate. Male cardinals and bluebirds, for example, wouldn’t need to be red or blue if the females were colorblind. A visit from the “gray bird of happiness” would not be nearly as exciting, and brown cardinals would not be very interesting. Imagine how boring that would be for us!
There is considerable disagreement about how well birds can see. Researchers are never certain which line on the eye chart birds can read because of the language barrier. The main issue is that there are approximately 10,000 distinct bird species worldwide, and each has a different degree of vision, making it difficult to make generalizations. While ducks see better underwater and owls see better at night, hawks have laser-sharp diurnal vision. And let’s not forget about peacocks. Have you seen all the eyes they have?.
Owls can see during the daytime despite having eyes with additional rods because they can It also doesn’t imply that the songbirds with cones are blind at night. They just don’t see as well as owls do. In fact, lots of non-owl birds are active at night. Songbirds make their long-distance migrations under the cover of darkness. When the tide is right, shorebirds feed, and many of them don’t seem to care whether it’s daytime or nighttime. And let’s not forget about carrier pigeons. They’ll fly anytime, not just nine to five. The unions haven’t gotten to them, yet.