Seeing well in the dark is the major function of an owl's eyes. Eye size is very important for seeing at night. Because an owl's eyes are so large, they have a large surface area to collect light. The light hits specialized cells in the eye that help animals see in low light levels. These cells are called rod cells. Owls have many more rod cells than other animals. In addition, owls have a structure called the tapetum lucidum at the back of each eye.
Light goes into the owl's eyes and hits the rod cells. It then bounces off the tapetum lucidum to hit the rod cells again. This lets the owl see the light two times instead of just once. And for an owl, this turns the night into day. You can see the tapetum lucidum when you shine a light at an animal at night. That glowing yellow or green shine you see is actually the tapetum lucidum bouncing the light back into the eye.
These structures, along with a large surface area and high numbers of rods, work together to give an owl exceptional night vision. As a matter of fact, an owl can see three times better in the dark than you can. Because owls have such big eyes and good vision, we tend to think that they hunt by sight.
Amazingly, owls hunt mainly by sound. Could you find your dinner by listening for it? The first thing you need to know about owl ears is that they are not on the top of the owl's head. There are several things that work together to give an owl excellent hearing. The first are the facial discs. These discs surround the owl's face and give the bird its distinctive look.
Made of several kinds of specialized feathers, the facial discs collect sound around the owl's head, just like a satellite dish collects signals for your television. Another adaptation owls have is their asymmetrical ear placement. This means that owl ears are not directly across from one another on the bird's head. If you put your fingers in your ears and look in a mirror, your fingers will most likely be at the same height. If an owl put its talons in its ears, one talon would be higher on its head than the other talon.
Having asymmetrical ear placement means that sounds reach the owl's ears at different times. As the owl lowers or raises its head, it can position its head so the sound reaches both ears at the same time. When this happens, it means that the source of the sound is directly in-line with the owl's face. Some species of owl also have a moveable ear flap that they can use to increase or decrease the sound coming to their ears.
So, how well can owls hear? A great gray owl sitting on a fencepost 60 feet away can locate a vole running in a tunnel under 18 inches of snow. A barn owl can capture prey when blindfolded. However, they cannot capture prey if one of their ears is plugged or if they lose their facial disc feathers.
For owls, when it comes to finding food, listening is definitely better than looking. Owls are known for their ability to fly nearly silently. This is because of the special shape to their wings and the structure of the feathers. Feathers are often called plumage. Most birds make a sort of flapping, swooshing sound when they fly. But owls have special edge on the front of the wing that breaks air into small streams of wind that rolls to the end of the wing where the comb-like feathers further break the air into even smaller streams.
This give them almost silent flight. The soft fluffy feathers of the legs also help to break up wind noise. The shape of the wing also gives them greater lift which allows them to reduce the amount of flapping required and helps them to sneak up on prey. This video from the BBC helps illustrate the difference in various bird wings and the sound made by their flight.
Owls are predators , which means they are also carnivores. They eat many different kinds of prey depending upon their own size. Small owls such as Pygmy owls and saw-whet owls are small, so they usually hunt for large insects and small rodents like shrews and mice. Owls pretty much eat whatever they can get their talons on. But their most common prey are small rodents such as mice and voles. These little mammals are important food sources for many animals. And that's a good thing, since they can be serious pests for people.
Larger owls also capture bigger prey like voles, woodrats, rabbits and squirrels. Great horned owls will even catch and eat skunks — yes, skunks! Other owl prey includes scorpions, lizards, snakes, frogs, toads, birds, bats and even fish. Not only do owls eat surprisingly large prey some species, like the eagle owl, can even grab small deer , but they also eat other species of owls.
Great horned owls, for example, will attack the barred owl. The barred owl, in turn, sometimes eats the Western screech owl. In fact, owl-on-owl predation may be a reason why Western screech owl numbers have declined. As harsh as it sounds, the parents always feed the oldest and strongest owlet before its siblings. This means that if food is scarce, the youngest chicks will starve. After an owlet leaves the nest, it often lives nearby in the same tree, and its parents still bring it food.
If it can survive the first winter on its own, its chances of survival are good. Many owls sleep in broad daylight, but the colors and markings on their feathers let them blend in with their surroundings.
Aside from hooting, owls make a variety of calls, from whinnies to whistles to squeaks. The barn owl hisses when it feels threatened, which sounds like something from a nightmare. The smallest owl is the elf owl , which lives in the southwestern United States and northern Mexico.
It will sometimes make its home in the giant saguaro cactus, nesting in holes made by other animals. The long-legged burrowing owl lives in South and North America. This makes owls one of the most ancient types of birds, along with chickens , pheasants, and turkeys. Contrary to popular belief, the eyes of an owl are not round at all. Instead, their eyes are tube-shaped or more cylindrical. To see their surroundings, owl have to turn their heads instead of sideways or upside down.
This means that owls mostly see in black and white vision rather than color. Researchers have found that certain hues of color are too intense for owls to see, such as the color red.
However, because of this, they are considered to have excellent night vision which allows them to hunt better at night. The majority of these owl species are categorized into the Strigidae family. These classifications of owls also have different anatomy than the common barn owl. Many often use barn owls as a form of pest control from small insects and mammals such as mice.
When owls hunt for small mammals, they swallow them whole in one piece. On average, owls can eat around 12 mice per night. One ear of the owl will always be higher than the other to help them locate their prey at night. However, because their ears are not aligned they will often hear sounds at two different times. This feature is a unique development attained by owls through evolution.
This is mostly caused by the loss of their habitats from deforestation. Its population also grows smaller due to hunting problems and certain illnesses inherent to owls. Because they lose their habitats, they also lose their major food source, threatening the overall ecology. True to its namesake, the Elf Owl only grows to a mere five inches tall. This owl species only hunts for small insects and spiders as its main food source. Elf owls typically live in woodlands and desert cactus habitats located in Southern Arizona.
During the night, it is said that the owl has great vision much similar to that of an eagle. Their eyes also have a reflective surface behind their retinas. While they rarely do so, owls can swim through water. However, these birds generally avoid swimming as they have no means of defense in the water. Owls also generally avoid getting soaked since they would be unable to fly with wet feathers. The facial disc of an owl allows it to funnel sounds of their prey to their ears. Many owl species will have their facial discs asymmetrically as their ears are also not aligned with each other.
The Northern Hawk Owl is one of the few owl species that is capable of hunting by using only its hearing. Research has stated that these owls can hear their prey underneath thick layers of snow during the winter. Once their prey is located, the northern hawk owl will swoop down on its prey and catch it with its sharp talons.
In the Aztec and Mayan culture, many tribes feared owls as they are considered to be a symbol of death. In Aztec mythology, the god of death is also often visualized with an owl by its side. The owl is considered to play an important role in urban ecosystems. This is mainly due to their ability to regulate movement with their prey. Apex predators are also known as alpha predators. These animals are considered to be the top of their food chain as no other animal regularly preys on them.
Their eyes are also powerful and adapt well to dark environments. With an average wingspan of to cm, the Great Grey Owl is one of the largest owl species found in North America by length.
Scattered across the northern hemisphere, the average adult great grey owl can weigh as much as 1, g. The male species are also generally smaller than the females of the species. These owls are known to prey on rabbits and ducks as well. They are also capable of catching faster prey such as the hummingbird and even raptors. The Eurasian eagle-owl will also occasionally hunt for other prey such as reptiles, amphibians, and fish.
The owl holds great significance in Ancient Egyptian culture. In ancient times, the owl was believed to be a guardian of the underworld.
Egyptians believed that the owl could protect the souls of the deceased and those who cross over to the underworld. This species of owl ranks among the largest living species of owls on the planet. These owls typically live in large and old trees as their nesting ground.
They commonly live close to lakes, rivers, or springs to use as a water source that does not freeze over during the winter. The first collected specimen for this species was taken from the Hakodate area in Hokkaido, Japan. More specifically, this particular tribe believes that an owl named Gordol created the world. Its facial disc size is considered bigger than any raptor or owl species.
The adult Great Grey Owl also weighs an average of a kilogram for its full-grown size. The release of the Harry Potter series increased the popularity of pet owls in several countries, particularly in Indonesia.
Hundreds of species were caught from the wild to be sold off as pets in bird markets. This trend was prominent up until the early s when the demand for pet owls slowly decreased. The owl has two stomachs. The first is referred to as the glandular stomach which produces the acids and mucus in its body to help the owl separate digestible and indigestible parts of its prey.
After swallowing its prey whole, the owl vomits out other indigestible remains such as its fur and bones. This species of owl is the only one found in the Genus Strix group in both the east and west hemispheres. The owl is a carnivorous bird known to prey on small mammals and insects.
However, some species of owls feed on their kind as well. Some owls, such as screech owls, appear to be monogamous throughout life. However, the pair-bond relationship of other owl species may last for only one brood.
Barn owls raise multiple broods in a single year if there is an abundance of prey. They may pick different mates for each brood. Barn owls may also have more than one brood if an early brood is lost to disease, malnutrition, predators, or catastrophic weather. Owls usually begin a nesting phase during the mating period, but they are not known for being diligent or skillful nest builders.
A lot of owls simply take over the nest that some other bird or animal has made. Once a good nest is found, owls may use it year after year. As the mating season draws near, female owls begin acting as if they are brooding even before there are eggs.
After an egg is fertilized usually within a day or two , it goes through several stages of development. The developing egg, which is known as the yolk, initially picks up several coatings of albumen egg white. It then gets two coatings of a material that forms the familiar hard shell.
As soon as the first egg forms a shell, another egg begins to develop. The first egg may be ready to lay as early as one day after copulation. Initially, eggs are laid individually every 1 to 2 days, but the cycle becomes erratic after the first few eggs have been laid.
Younger chicks are more vulnerable to starvation because it becomes harder to feed the entire brood as the number of hatched chicks increases.
Several days or even weeks can separate the oldest egg from the newest. During the incubation process, female owls rarely leave the nest except to defecate and get water.
To help with incubation, female owls have a sparsely feathered brood patch on their bellies that has a higher percentage of blood vessels than other parts of the skin. Blood flow through these vessels creates a good source of heat for the eggs.
Although most owls begin incubating eggs as soon as the first is laid, others may wait for hours or days to begin. When the incubation begins immediately, some chicks hatch far sooner than others.
This can lead to the older chicks helping to brood and feed the younger chicks. When prey is scarce, however, it can lead to the older chicks cannibalizing the younger ones.
Like all birds, owls are born with an egg tooth. This structure helps them chip away from within and break the tough eggshell. This tooth drops off weeks after hatching. Although owls are born blind and have only a thin coat of down to protect them from cold weather, a thicker coat appears within a couple of weeks. Barn owl chicks are notorious for their curious, wandering behavior.
Owlets often beg vocally for food. Since more predators lurk nearby, those owlets on the ground are much quieter than those nested in trees. The parents of young owls provide them with food soon after they have hatched. Many species provide insects to their young in the early stages and whole rodents once the chicks become large enough.
Spotted owls rip off the heads of their prey so that digestion and owl pellet production are easier for the chicks. In some species, such as great horned owls, the parents provide larger and larger prey as the owlets increase in size. Many young owls take their first flight, or fledge, by the time they are 2 months old. Once an owl begins flying, parental support dries up.
The parents may chase the young away or simply abandon their nests. The young are subsequently forced to feed themselves. Adult owls are near the top of the food chain and are not threatened by many animals.
Large raptors, such as eagles, may attack owls if food is scarce. Likewise, large owl species may attack smaller ones on occasion. Owlets are much more vulnerable, however. The more chicks in a given brood, the less likely all will survive disease, malnutrition, or catastrophic weather. Predators of owlets include snakes, squirrels, possums, and ravens. All of these animals are preyed upon by species of larger owls.
The influence of humans can also lead to chick mortality. Chicks often die directly from human interference, such as deforestation and illegal hunting. Owls also frequently fly into cars, windows, or clotheslines. The mere presence of humans may cause the parents to abandon the nest and the young. Long-term studies have shown that the survival rate of owl chicks goes down as the number of humans in the area goes up.
Young adult owls are also vulnerable because of their lack of hunting experience. They could be pushed by their parents or other adults into unfamiliar hunting territory inhabited by other hostile adult owls. At least half of all young adult owls die before they reach their first birthday.
The odds of survival increase greatly as they gain size and experience. Most owls in the wild live about 10 years.
However, owls can live much longer if conditions are favorable. Great horned owls in the wild have been observed to live for 19 years, whereas long-eared owls have lived up to 27 years. Owls can live for many more years in captivity than they would in the wild. The record for longevity in captive great horned owls is 38 years, which is twice as long as the record age for longevity in the wild.
Feather lice can torment owls and can also pose health problems. Owls are also susceptible to a variety of parasitic worms. Fleas and flies pester owls, but they only hang around because of the decomposing materials typically found in owl nests. Hepatosplentitis infectiosa strigum is a virus that is fatal to many owls, but some species, such as barn owls, have become immune to it. Owls are also vulnerable to pneumonia and tuberculosis.
Pigeons, which are preyed upon by some species of owls, carry a parasitic protozoan that may cause a thick deposit to form in the throats of owls. This deposit can eventually cause an owl to choke to death. Barn owls are renowned for making nests in manmade structures, but most other species of owl seek out shelter away from the influence of man.
The cavities of rotten trees, or trees hollowed out by woodpeckers often host owl nests. Owls also readily seek out the abandoned nests of other species of birds such as eagles, hawks, or crows. Some owl species also use the cover provided by caves and niches in rocks to provide them with protection from the elements.
Great horned owls run squirrels out of their nest, squash it flat, and take it as their own. When owls do construct their own nests, the quality of workmanship is shoddy at best.
Barn owls typically don't even attempt to build a nest. The only comfort and protection that barn owl chicks get is from the regurgitated owl pellets that are strewn around the nesting area. Owl nests become coated with excrement and uneaten animal parts, making them very filthy compared to the nests of other species of birds. Burrowing owls do try to provide a good nest for their young.
These birds nest in holes dug in the ground insulated with grass, plant stalks, and other material, which provides protection for their young. Raptors such as owls don't always have it easy just because they are on top of the food chain. Smaller birds attack and pester owls caught flying in the open or roosting.
Many types of birds may join the owl assault, which is known as mobbing. Songbirds most commonly attack owls, but birds as large as crows and as small as hummingbirds join in, also.
The harassment that occurs during mobbing usually consists of repeated dives as well as loud vocal calls designed to alert others to the owl's presence. Sometimes birds physically attack, plucking at the owl's eyes and feathers or clawing at its body. Owls are seldom hurt by these attacks and seem to ignore the mobbing behavior of other birds. Throughout history, owls have been linked to unnatural forces, evil, and death.
Ancient Babylonians believed that the hoot of an owl at night came to represent the cries of a woman who died during childbirth. In Hungary, the owl was referred to as the bird of death. Owls were official symbols of death for ancient Egyptians. The hieroglyphic for the owl also symbolized darkness, cold, and a state of passivity. Ancient Romans considered the sight of an owl an extremely unlucky omen.
According to legend, the only way to negate the effects of this omen was to catch the owl, burn it, and then scatter its ashes in the Tiber River. It has been said that before Julius Caesar was murdered, owls were heard making their mournful cries. However, not all societies and cultures have assigned negative attributes to owls.
Buddhists have long thought the owl to be an enemy of ignorance and a representation of isolation and the need for deep meditation. In Athens, owls represented a force of mystery, but one associated with good. The owl was the symbol of the Greek goddess Athena, goddess of night, war, wisdom, and the liberal arts. In many ancient cultures, owning or carrying a piece of an owl as a charm was thought to provide special protection from evil spirits and health problems, such as epilepsy and rabies.
Other ancient cultures believed that energy, wisdom, and bravery might be imparted to the carrier of owl charms. Different cultures used different parts of owls in their charms, including the feet, feathers, eyes, heart, bones, or even the entire owl.
There are many natural areas named after owls in the United States. Lakes, rivers, bays, swamps, and mountain ranges contain "owl" in their names.
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