Many living creatures sleep lying down with their eyes closed. But then there are the few that sleep standing up, hanging upside-down, floating on the water, or with their eyes wide open. Where do birds fit into all of this? How do you know if a bird is asleep or awake?
In many ways, birds are similar to mammals when it comes to sleeping. In other ways, they are wildly unique, including the fact that they can deliberately turn one side of their brain “off,” and sleep with one eye open.
Read on to find out more about how birds sleep.
Do birds close their eyes when they sleep?
Birds most often sleep with their eyes closed. Although they may sleep on their feet, they often relax into an almost sitting position.
A sleeping bird is easy to spot. Usually, feathers will be slightly fluffed, and breathing will be gentle but rhythmic. Some birds will also tuck their head over their shoulder and pull one leg up close to their body.
Like mammals, birds pass through a pattern of non-REM and REM sleep cycles. REM stands for rapid eye movement.
During this phase of deep sleep, the eyeball moves swiftly back and forth behind the eyelid as if the sleeping animal is watching her dreams unfold. Both sleep cycles are shorter for birds than for mammals.
The non-REM cycle lasts for an average of two minutes, while REM sleep lasts for only about nine seconds at a time. This means birds are constantly waking or almost waking briefly throughout the night.
You may want to also check out our interesting article about how much sleep do birds need.
Why can birds sometimes sleep with one eye open?
Have you ever wished you could catch a nap while keeping one eye open to watch out for something or someone? Birds can actually do this.
Only half of the bird’s brain rests during unihemispheric slow-wave sleep, and the other half stays alert.
This way a bird can rest while keeping one eye out for predators. Some migrating birds can even sleep while flying.
Unihemispheric Slow Wave Sleep
The phrase “half-awake” is often used to describe someone who has just been roused from a deep sleep and is not quite alert.
Birds can be literally half-awake, and unlike some animals that share the capability of unihemispheric slow-wave sleep, they can control how awake they are.
A bird that is dozing with one eye closed and one eye open is sleeping with half his brain while the other half stays awake.
How open the eye is determines how asleep the bird is. So, a bird with an eye cracked open is mostly asleep but somewhat alert.
Why a bird may stay half awake
Birds are naturally light sleepers under normal conditions. Because of this, they are easily disturbed.
A bird in your home may be unable to enter complete sleep due to a noisy environment or because she is interested in something you are doing nearby. A fearful bird – one that is in a new setting or feels threatened in some way – will also often sleep with one eye open to watch for danger.
How do bird eyelids differ from human eyelids?
Those who haven’t had a lot of interaction with birds may wonder if birds even have eyelids. The answer is yes. All birds have eyelids. In fact, they have three eyelids—an upper lid, a lower lid, and a third semi-transparent membrane.
This is not the only way their eyelids are unique.
- Most birds don’t blink regularly like people with their outer lids. Instead, the third, inner eyelid – called a nictitating membrane – cleans and moistens the eye. Often the blink is so quick, it can’t be seen by the human eye. Some birds are the exception, of course. Owls, parrots, and ostriches, for example, will close their outer lid when blinking.
- The nictitating membrane is not only for blinking. Birds also use it to protect their eyes while feeding their young. Raptors may close it during a highspeed dive and water birds may close it when ducking underwater in pursuit of fish.
- Some birds close their eyes by raising the lower lid, while others lower the upper lid.
When do birds sleep with both eyes closed?
Birds will also sleep with both eyes closed if the circumstances allow it. This is the most restful sleep state, and it’s important they enter it occasionally.
When they’re very tired
A bird that has been completely worn out by an exciting or stressful activity or day will most often sleep with both eyes closed.
This bird needs his rest! A bird that is sleeping with both eyes closed but doesn’t appear fully comfortable (feathers are tight against the body, sitting up tall and rocking slightly on perch) may still be somewhat stressed and needs to be moved to a quieter area where he can relax.
When they feel safe and comfortable
A bird that feels safe and comfortable will have no problem closing both eyes to sleep. If your bird happily dozes off with both eyes closed, it usually means you’re doing something right.
Read more here on how to tell if your bird is bonded to you.
When they’re sick
Just because a bird is sleeping during the day with her eyes closed, it doesn’t mean she’s sick.
As we mentioned above, she may just be tired and happy. However, if other symptoms are visible and she seems oblivious to activity that would normally rouse her, there may be an underlying health problem.
Do birds lie down when fully asleep?
Some birds do. Certain species of parrots, like conures, are notorious for snuggling up under newspapers for a nap or even sleeping on their backs in the bottom of their cages.
However, a bird does not need to lie down to rest both hemispheres of his brain. Most birds choose to sleep perched on a sturdy perch in a sheltered area where they feel safe.
Do birds ever fall off perches while sleeping?
When a bird’s weight is on its feet, the muscles in its legs pressure the tendons in such a way that it forces the foot to close.
This way a bird will continue to hold tightly to the perch even while asleep. Unless a bird is very young or old or is sick or injured in some way, it is very unlikely to fall from its perch while sleeping.
Helpful tips for when your bird is sleeping
Despite the fascinating capabilities birds use to deal with interrupted sleep, they do still need plenty of it to remain healthy and happy. It’s important to be considerate of any bird you keep in your home and make sure he doesn’t always need to resort to unihemispheric sleep to get his rest.
- Make sure your bird feels safe. If a bird’s cage is too close to a window or a main thoroughfare through your home, he may always feel he needs to keep an eye out for danger. The stress of feeling unsafe is as bad for the bird as the sleep he’ll miss out on, so it’s important that your bird does not feel constantly insecure.
- Provide a satisfactory sleeping area. Most birds prefer to sleep on the highest perch in their cage. If you notice your bird hanging on the bars of the cage to sleep, it may be because none of his perches are high enough or sheltered enough for him to feel safe. Providing a sturdy, comfortable perch specifically for sleeping will give your bird a place to settle when he is ready to rest.
- Keep noise and activity to a minimum. If your bird needs to rest, you can help by keeping the noise level to a minimum, turning the lights down or covering the cage, and keeping activity (and anything that may be perceived as a threat, like other pets or small children) away from the bird’s cage.
- Interfere as little as possible. If your bird is sleepy, let her sleep. If she’s been out and about with you for several hours and is falling asleep on your shoulder, it may be a good idea to transfer her to her cage or play stand so she can rest without interruption.
What to do if you see your bird sleeping with one eye open
If your bird always seems to sleep with one eye open, check for anything that may be stressing him.
Are other pets or people making him nervous? Does he see some perceived threat outside of a nearby window? Is there a higher level of noise or activity in the house than usual? Has your bird been getting enough sleep at night?
In most cases, there’s no need to be concerned if you see your bird sleeping with one eye open. This is a perfectly natural way for a bird to catch a nap or doze off during a boring movie.
It’s best to avoid startling your bird in this half-asleep stage. Try to speak softly to him when you approach the cage and warn him if you’re about to make a loud noise.