Do Birds Sleep With Their Eyes Open? What Are They Watching Out For?

If you look carefully, you might have seen your pet parrot seemingly winking at you and not responding to your actions. Do birds sleep with their eyes open? Or is it always just the one eye?

Do birds sleep with their eyes open

No, they don’t sleep with their eyes open all the time, but they do often sleep with one eye open.

You see, birds can literally sleep with one eye closed and the other eye completely open and alert, just like a few other select animals like dolphins and fur seals.

The only difference between birds and other animals that have this unique ability is that birds are the only ones known to be able to control it. And no, they aren’t winking at you.

How Do Birds Sleep With One Eye Open?

This is because they have evolved with unihemispheric slow-wave sleep abilities or USWS for short.

All this fancy term means is that each side of their brain can work independently from the other.

So half of the brain can be fast asleep while they keep the other half of the brain active and alert, looking for predictors or any other alarming information.

They can do this because, unlike us, each eye is “attached” to only one side of their brains. So each half can work independently as far as outside stimulation is concerned while the other half rests or roosts.

This gives them the ability to monitor their surroundings twenty-four hours a day. 

Why Have Birds Evolved to Sleep Like This?

Birds have evolved this fascinating ability (known as “peeking”) so that they can keep a (literal) eye on their surroundings and improve their chances of survival.

In their natural environment, birds have several predators, such as snakes, wildcats, owls, and other wild animals who will prey on them.

That is why they have taken to several strategies that help them protect themselves from these creatures, one of which is to sleep with their eyes open.

And while we are not completely sure that this is the reason, there are studies to show that most animals sleep less deeply under fear of predators.

Do birds sleep with their eyes open

What Other Ways Do Birds Protect Themselves When Sleeping?

Sleeping in flocks and keeping their bills and legs tucked in to keep warm are other ways in which birds protect themselves when asleep.

Sleeping in Flocks

By roosting together, many types of birds, such as passerines and bluebirds, avoid predators and also keep themselves warm. 

In a communal roost, these birds sleep in a small, confined space, which helps them maintain body heat and share it with others in their flock.

Tucking In Their Bills

Birds’ feathers can keep the rest of the body warm, but certain parts of their bodies, such as their bills, do not have a feathery coating. 

Many birds, such as ducks and flamingos, bury their heads in their shoulders to maintain heat and protect these body parts from harsh weather.

Contractable Legs

Birds have a flexor tendon in their feet that lets them contract their toes and talons when their feet are bent. 

This way, they can sleep with their toes and talons tucked deep in their feathers while they are on their perch. This is also how they can lock on to their perch and not fall off while sleeping.

Sleeping on Water

Birds that can wade or waterbirds that can swim often sleep in deep waters. This helps them stay away from land predators while they are asleep.

We’re sure those guys are getting a solid rest as compared to their land-only cousins!

Do birds sleep with their eyes open

Sleeping While Flying

Some birds, such as frigatebirds and swallows, can sleep while flying. They use the same USWS sleep mechanism to help them do this. 

Research has proven that some birds can fly for as long as two hundred days straight while napping simultaneously, thanks to their USWS ability.

This is a great way for them to protect themselves from land predators and also fly long distances at a stretch. 

Do Birds Always Sleep With One Eye Open?

No. Most of the time, if a bird is comfortable with its environment and does not expect predators or any other dangers to invade its sleeping space,  it will sleep with both eyes closed.

However, birds have a very different sleep pattern as compared to humans.

For one, birds have very short bursts of REM and non-REM cycles. REM or Rapid Eye Movement is a stage of deep sleep where an animal’s eyes move rapidly from side to side. This type of sleep is commonly called deep sleep. 

For humans, these REM and non-REM cycles last about 70-100 minutes, and as the night progresses, it can go longer.

For birds, however, REM sleep lasts only 9 seconds! That means that birds are very light sleepers and can become awake at the slightest noise or sound.

In fact, even their non-REM cycle lasts just two minutes, so they are basically just flitting between deep sleep and light sleep all the time. This, despite the fact that most birds need up to 12 hours of sleep!

Do birds sleep with their eyes open

How Can You Help Your Bird Sleep Better?

We discussed that birds sleep better when feeling safer. Therefore, the most important thing to do is to give your pet birds a safe environment. Here are some things that you should take care of:

Give Them a Friendly Place to Sleep

When you have a landscape or a bird house where they can comfortably perch, they sleep better.

Make sure that it is away from predators and still in a place that feels like home to them; they are bound to sleep better. Try to put their bird house in coniferous trees with a brush pile.

Keep Your Pet Cats as Far as Your Can

Cats are natural predators of birds, so as long as a cat is around, your pet birds will never feel safe. However, ensuring that your bird home is far away from the reach of your cat, high up in an inaccessible place, will help.

Give Them Healthy Food

Birds that eat better sleep better. Bird diets should be high in calories, proteins, and essential vitamins and minerals to keep warm in the cold winters.

Give Them a Quiet and Distraction-free Space

Birds will often mistake your house lights for natural light, and this can disturb their sleep cycle. It is important to give them a dark space. 

Some birders cover birdhouses at night to provide a dark space, but this can make cause them stress because they are unable to see the environment around them.

Instead, try to keep a separate space in the house where there are no distracting sounds or lights at night so that your pet birds can fall asleep more comfortably.

Do birds sleep with their eyes open

Wrap Up

To conclude, birds sleep better and with both eyes closed when they are safe.

As long as they feel threats or predators around, they have many ways to defend themselves. And one of their most unique adaptations is to sleep with one of their eyes open!

But birds don’t need to sleep this way, especially the pet ones that we love and care for.

If we give them a safe and comfortable home away from predators, disturbances, and noise, they can comfortably sleep with both their eyes close.

Gordon Ramel

Gordon is an ecologist with two degrees from Exeter University. He's also a teacher, a poet and the owner of 1,152 books. Oh - and he wrote this website.

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