With over 250 species of owl distributed throughout the world, they vary in size and shape. From the tiny elf and pygmy owls, which can fit into a hand, to the huge eagle owl and fish owl, they all have unique adaptations that allow them to hunt at night.
Owls have excellent vision and sound, allowing them to pinpoint their prey before pouncing on them. Although they cannot move their eyes, their heads can turn 180 degrees, allowing them to look in all directions. Owls have fringes of the ends of their wings and soft feathers, which allow them to fly almost silently.
Owls, being part of a large family, feed on different types of prey and occupy different habitats and niches. These differences allow owls to thrive. Short-eared owls and long-eared owls will hunt the same prey but in different habitats. The short-eared owl will hunt voles during the day over marshes, while the long-eared owl will also hunt voles at night in the woods.
While large eagle owls can prey upon small deer, the elf owl will feed on moths, beetles, and crickets. The fish owl will feed, as its name suggests, on fish. Because owls are so different in their habitats and feeding habits, they also have diverse adaptations. However, their adaptations to being nocturnal are similar.
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Using excellent vision
Like ourselves, owls have their eyes set on the front of their head, allowing them up to 110 degrees of vision. Because both the eyes are close together, they can judge distance accurately, something that is essential in a predator. Predators, such as owls, can see in three dimensions, including height, width, and depth.
Owls have excellent eyesight, but having the eyes on the front of their heads does restrict what they can see at the sides. To compensate for this, owls can turn their heads at least 180 degrees, allowing them to see behind them. This will enable them to locate their prey without moving and alerting them but also help them guard against predators.
Although the angle of the head turn is remarkable, it is the size of the eyes that is most striking. They take up a large portion of the front of the head, separated from each other by a thin layer of bone. Eyes have a nictitating membrane which helps to protect them against bright light and particles such as dirt or dust.
The eyes fit into the eye cavity tightly, with no space for controlling muscles. Due to this, the eyes cannot be moved, and the birds rely on their necks to look in different directions and angles.
Owls’ eyes are different from other animals in other ways. They have tubular eyes which are deeper than they are wide. They can contract and expand the iris greatly, allowing them to use every bit of light in dark conditions and close out most of the light when faced with extreme brightness. The eyes consist of more rods than cells, allowing them to see well in dim light, although they can spot a predator before a human being.
Amazing hearing
Because owls generally prey on small animals, they have to rely on their excellent hearing to find them. Because their prey is small and scurrying about in the underbrush, owls cannot rely on their vision alone. Owls have a wide outer ear tube which allows them to hear a large range of frequencies.
Some owls have assumetric ears, allowing them an almost three-dimensional sense of hearing. They can hear sounds coming from behind them as well as from the sides and in front. Many owls have large ear tufts, but these don’t enhance the sound and are used for courtship displays and threaten others.
Silent wings
Owls cannot locate their prey in pitch darkness, but their excellent vision and hearing allow them to hunt in low-light conditions. They will pinpoint where their prey is using both senses before pouncing on it. Owls are extremely good at being quiet when they fly, but as with all birds, they make some noise.
Nocturnal owls have different feathers than The feathers on an owls wing are incredibly soft with a velvet-like surface and a fine fringe. This effectively deadens the sound, allowing owls to swoop down on their prey almost silently. Nocturnal mammals also have excellent hearing to keep them safe at night, but it is almost impossible for them to hear an owl until it is too late.
The noise that an owl that hunts in the daytime makes is very different. Eagle owls are much larger and louder, and although they are not as quiet, their prey’s hearing is also not adapted as well as their nocturnal cousins.
Sharp claws and bill
The only species of nocturnal bird of prey is the owl, but as with eagles and hawks, they are superb at killing and eating the animals they catch. Owls have large, powerful feet with long toes and sharp, grasping talons. While they have three forward-facing toes and one backwards-facing toe. This allows them to perch, as is common with many other birds.
When an owl is about to pounce on its prey, they change the position of their toes, reversing the outer toe so that two face forwards while the other two face backwards. This allows them to grasp their prey tighter and a larger spread, giving them little chance to escape.
The bill of an owl is a weapon in itself. They are designed to tear, dismembering their prey into easy to digest chunks. The bill is hooked and is sized depending on the owl and their usual prey. An owls beak does not get the recognition it deserves as most of it is hidden under the soft feathers of the face.
Staying hidden
Most owls hunt at night, so there is no real reason for them to be camouflaged from their prey. However, owls, even during the day, can be hard to spot due to their colours. This helps to protect them from their predators and the attention of other birds. All birds can get mobbed by other birds, and even the mightiest eagle can bother a flock of crows.
Because the attention of a group of mobbing birds can alert other animals to an owls presence, nocturnal owls spend a lot of their time hidden away in a hole in a tree or vegetation against a tree. Their camouflage helps them stay safe during the day when many small birds are out.
Their colours are often muted, which allows them to fly around at night without their prey seeing them.
Owls have adapted to nocturnal life because most small animals are also nocturnal. By adapting to the dark, owls have a bountiful supply of food.
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