Birds are one of the creatures that need their eyes the most. Without good vision, they are often unable to navigate through the skies, and would not be able to see to swoop down and capture their food for survival.
This is why a bird’s sight is paramount and probably their most important sense. But what about night time? Are birds able to see clearly at night?
That’s what our guide is here to find out! We’ll talk about which birds have night vision, which don’t and the anatomy of a bird’s eye to help you understand the parameters of a bird’s vision at night time.
Can Birds See At Night?
The short answer is yes, birds are able to see at night. However, some birds have better vision than others. For instance, birds like owls, frogmouths and bat hawks have extremely powerful night vision as this is when they are most active, hunting and flying in the night time.
On the other hand, birds that are active during the daytime have poorer night vision, but can still see to some extent during the night. That being said, even birds with excellent night vision are not able to see fully in complete darkness, but will be able to see in some dark conditions.
A Bird’s Eye View
As we touched upon the topic above, birds need their eyesight more than many other animals in order to survive. It’s how they locate food, spot predators, search for mating partners and of course, their eyesight is how they are able to maneuver themselves through the skies.
So, what is the anatomy of a bird’s eye, and how do they work? Well, much like human eye anatomy, bird’s eyes are made up of similar sections such as the cornea, retina, lens and more.
You have birds such as owls and eagles that have eyes about the same size as human eyes, whereas other birds like the ostrich have eyes twice the size of human eyes! However, that’s pretty much where the similarities end.
Birds have eyes that are more closely related to reptile eyes as they are not spherical like ours, and have a much flatter surface so that birds are able to comprehend visual fields much more easily. In addition to this, birds also have lenses that are more far forward, which helps to improve and enlarge the size of the image that they see.
Due to the size of the pupils in a bird’s eye, they are able to gain more light in the eye. This is why birds are able to see in darker light conditions and can see better in the dark or at night time.
In addition to this, the wall of the eyeball has three layers in total. These are made up of the sclera and cornea, which is part of the outer layer, with vascular cells in the middle layer and a retinal layer on the inside of the eye.
In comparison to human eyes, we have about 200,000 photoreceptor cones per square millimeter in the retinas, whereas birds have double that with about 400,000 photoreceptors. This is how birds are able to see things in far more detail than we can. So, how well can birds really see?
How Well Can Birds See?
Birds can see incredibly well, and have great eyesight. Additionally, they are also able to see colors really clearly, and even have motion detection skills.
For the most part, birds are referred to as tetrachromats, which means that they can see four colors, whereas humans can only see in three. Birds are therefore able to see red, green, blue and UV, whereas we can only see in red, green and blue.
Birds have great color perception, and have a sort of sensory perception that lets them see direction, altitude, and location. Which comes in super handy when flying! This type of perception is called magnetoreception which is how birds are able to navigate themselves, especially when there is minimal light or dimmer light conditions.
They are also thought to have the ability to see plane-polarized light, which gives them a sort of compass that can be used when there is little to no light. With over 400,000 photoreceptors, birds are also able to use these to detect colors, and understand their location and altitude when in the air.
Studies suggest that birds’ ability to see in UV gives them a much greater advantage over other animals. However, it is not just birds that can use UV vision. Some fish, reptiles and amphibians are able to do this too.
It is this UV vision that gives them the opportunity to see insects, food, berries and other animals much more easily, and from greater distances. This is how birds of prey are able to zone in on their prey from miles away, and how owls can see prey even in the dark.
What you may be surprised to learn is that a bird’s UV vision can also be used for them to see which sex a monomorphic bird is so that they will know whether they are able to mate with them or not.
Birds are also able to use their vision to detect motion. They are actually able to keep track of moving objects very easily, and can see this from great distances too. Compared to humans, birds are able to see about twice as much movement, with about 100Hz, whereas we can only see about 60Hz.
Birds of prey also have increased motion detection abilities, and can track moving objects, prey or other creatures with incredible accuracy and precision. This is why a bird of prey will be able to spot their next meal and swoop down before the creature even knows that it is being watched.
Does Vision Depend On Whether They Are Nocturnal Or Diurnal?
All types of birds can be split into two categories; diurnal and nocturnal. Nocturnal birds are most active at night, and will likely sleep during the day, whereas diurnal birds are the opposite, and will be most active during the day.
Nocturnal birds will be ones as their names suggest like nighthawks, nightingales, owls, nightjars and night herons. On the other hand, diurnal birds will be falcons, hawks, eagles, hummingbirds, woodpeckers and parrots.
It is thought that nocturnal birds have better vision, as they must forage, fly, explore, hunt and care for their young during the night, where light is scarce. These types of birds therefore have certain rods in the eye to give them night vision, and the ability to perceive movement, shapes, and silhouettes during the darkest light conditions.
To compare, diurnal birds tend to have less of these rods in the eye and not as perfect vision at night. That being said, they are not unable to see at night, and they are not completely blind during dark light conditions, they just have limited night vision.
To give you an idea, even diurnal birds can still see better than us in the dark so they are not at a disadvantage really.
What Do Diurnal Birds Do At Night?
Most diurnal birds will sleep during the night, and will take shelter in trees, small cavities or cozy alcoves where they will be safe. In colder climates, birds may even huddle together to stay warm.
Aquatic birds such as geese and ducks will simply sleep on the water and float peacefully, whereas ostriches will sleep in the same way that herons and flamingos do, by standing up. Despite all of that, some diurnal birds get up to other activities during the night such as singing, dancing in mating displays and even migrating.
Some birds will sing at night to mark their territory. This is often to create so much noise that it wards off other birds and keeps them away from their nests and territory. Another reason why a bird may sing in the night is to attract potential mates with a mating call.
Birds can also be found dancing at night in a ritual that is called sky dancing. This is when male birds will perform a mating or territorial display where they go higher and higher into the air, before plummeting back to the ground again. This is often to attract female birds, and will sky dance throughout the night.
Some birds will use the night hours to migrate to another location. This is often to protect themselves from predators and they will use the stars to navigate themselves.
Do Birds Have Monocular Or Binocular Vision?
Birds can have monocular and binocular vision. Birds with binocular vision like owls and eagles have eyes that are in the front of their heads, much like humans do.
On the other hand, birds with monocular vision have eyes that are able to focus on multiple things at once, and can see different things. Therefore, they are able to see what is in front of them and what is around them wherever they are.
These types of birds have an increased field of views, whereas birds with binocular vision have a greater depth perception.
To conclude, birds actually have greater eyesight than most animals. The majority of birds can also see at night, but nocturnal birds have the best vision at night as they have many more rod cells. But, this does not mean that diurnal birds cannot see at night too, they just don’t have as clear vision as nocturnal birds.