Birds have very different sleep patterns compared to humans. While we typically sleep for 6-8 hours at night, birds tend to sleep in short bursts throughout the day and night. But how much total sleep do birds actually need? Here we dive into the fascinating science behind avian sleep.
Do Birds Sleep at Night?
Most birds do sleep at night, but their sleep is quite different from ours. Birds tend to sleep in short bursts rather than sleeping solidly through the night. They may sleep for just seconds or minutes at a time, alternating between short naps and brief periods of wakefulness. This is very different from human sleep, where we sleep in a single long bout.
Studies have shown that birds like sparrows and pigeons sleep in episodes averaging 2-10 seconds. This rapid cycling between sleep and waking states allows birds to remain alert to any potential dangers that may arise. If a predator approaches, they can quickly wake up to fly away.
In addition to these short microsleeps, birds also engage in longer naps. Some species may snooze for up to 30 minutes while roosting or perching. Ducks, geese and other waterfowl often nap while floating on the water. So while birds don’t sleep continuously at night like humans, they do get intermittent rest by cycling through short sleep sessions.
Do Birds Sleep During the Day?
Yes, birds do sleep during the day as well as at night. In fact, some birds are very active at night and prefer to get most of their sleep during daylight hours. Species like owls and nighthawks are nocturnal hunters, so they are awake hunting tiny prey all night long. To make up for lost sleep, they’ll snooze off and on during the day. Other birds are partially nocturnal and may balance both daytime and nighttime sleep.
Diurnal birds that are active during the day also take short daytime snoozes. Perching birds like sparrows may nap while sitting on a branch in between foraging sessions. Eagles, hawks and other raptors frequently nap while soaring high overhead. The rising thermal air currents allow them to coast along without flapping their wings, so they can rest without dropping out of the sky!
So in summary, all types of birds get some sleep both at night and during daylight hours. The exact timing and amount depends on the species’ lifestyle and daily rhythms of activity.
Why Do Birds Sleep Differently Than Humans?
Birds have evolved very different sleep patterns compared to humans for a few key reasons:
- Staying safe – To avoid predators, birds need to remain vigilant even when resting. By sleeping in brief bursts, they can keep one eye open for danger.
- Brain structure – Avian brains have different architecture and neurotransmitters than mammalian brains, which may enable fragmented sleep.
- Unihemispheric slow-wave sleep – Birds can sleep with one half of the brain at a time, allowing the other half to stay awake and watch for predators.
- Flight adaptation – Shorter sleep episodes may prevent birds from falling into prolonged deep sleep, so they can take off quickly.
So in essence, the unique demands of the birds’ lifestyles have shaped their unusual sleep physiology and habits. Their light, intermittent dozing allows birds to meet their sleep needs while staying safe on the wing!
How Many Hours Do Birds Sleep Each Day?
When all the short sleep sessions are added up, how much time do birds actually spend sleeping in a 24-hour period? Here are some estimates:
Bird Type | Total Sleep Time Per Day |
---|---|
Hummingbirds | ~2-3 hours |
Finches | 3-4 hours |
Parrots | 9-12 hours |
Pigeons | ~3 hours |
Chickens | 4-6 hours |
Ducks | 6-8 hours |
Owls | 9-12 hours |
As you can see, daily sleep times range widely depending on the species. Tiny hummingbirds that burn energy rapidly may get by on only 2-3 hours. Larger parrots and owls that don’t expend as much energy while perching may sleep up to 12 hours.
So smaller, more active birds tend to sleep less than heavier, slower-moving types. But in all cases, birds sleep much less overall than humans, who need 7-9 hours of consolidated sleep each night.
Do Birds Ever Experience REM Sleep?
REM (rapid eye movement) sleep is the deep restorative phase of sleep associated with dreaming in humans. Do birds exhibit similar REM sleep?
Research shows that birds do experience REM sleep, but only in very brief spurts. Their REM episodes may only last a few seconds compared to the 10-15 minutes seen in human REM cycles. Also, birds don’t need very much REM – some seabirds have been shown to do just fine with only 3-5 minutes of REM sleep in a day!
Scientists believe evolution has trimmed down avian REM sleep to just the bare essential amount needed. Too much prolonged REM could leave birds vulnerable to predation for too long. So like most other aspects of their sleep, birds’ REM cycles are extremely abbreviated compared to humans.
How Does Migration Affect Bird Sleep Patterns?
The amazing long-distance migrations undertaken by many birds greatly impacts their sleep needs and patterns. Some interesting effects of migration include:
- Increased total sleep – Birds preparing for migration may increase their total sleep to stock up on rest beforehand.
- Unihemispheric sleep in flight – Flying migrants can sleep with half their brain to stay on course.
- Decreased daily sleep – Birds may cut back on sleep while actively migrating to maximize flying time.
- Mid-flight catnaps – Some birds take short mid-air naps lasting just seconds by gliding on thermals.
- Post-migration recovery sleep – After migration, many birds go through several weeks of increased sleep to recover.
So migration puts birds’ adaptable sleep habits to the test. Amazingly, birds are able to modify their flexible sleep as needed to accomplish these incredible feats of endurance.
How Does Torpor and Hibernation Affect Sleep Needs?
Some birds have the amazing ability to lower their body temperature and metabolism to enter torpor or full hibernation. This allows them to save energy when food is scarce. How do these states impact their sleep requirements?
During daily torpor, a bird’s sleep needs are reduced along with their temperature and metabolism. A bird in a hypothermic torpor may need just a third of their normal sleep. This allows them to devote more time to foraging instead of sleeping.
Hibernating birds like poorwills can drop their body temperature even further and enter periods of deep hibernation lasting weeks. In this state their need for sleep is practically eliminated. The bird remains in a dormant low-energy state until conditions improve.
So torpor and hibernation allow birds to drastically cut their sleep needs during harsh conditions. This helps maximize their chances of survival when resources are low.
Do Baby Birds and Nestlings Sleep Differently?
Baby birds have some notable differences in their sleep patterns compared to adult birds:
- More total sleep – Nestlings sleep up to 75% of the time as they grow and develop.
- Less REM sleep – Baby birds have much less REM sleep than adult birds.
- No unihemispheric sleep – Nestlings initially sleep with both sides of the brain until REM sleep matures.
- Parent-assisted arousal – Parents may awaken chicks from sleep to encourage feeding.
- Frequent night waking – Undeveloped circadian clocks cause frequent night wakings.
But within a few weeks after hatching, baby birds transition to more adult-like sleep patterns dominated by short bursts of unihemispheric sleep.
Do All Birds Sleep While Standing/Perching?
Most birds have the remarkable ability to sleep while perching or standing on their feet. However, not all birds use this ability:
- Many perching birds like songbirds and pigeons commonly sleep while perched.
- Wading birds and seabirds may sleep standing while wading or floating on the water.
- Owls and other cavity nesters often sleep while clinging vertically inside tree holes or nest boxes.
- Some birds like ducks and chickens prefer to sleep while sitting or lying down.
- Very large birds like ostriches and emus are unable to sleep while standing on one leg.
So while many birds can sleep while perched, others only exhibit this ability to a limited extent or not at all. Their anatomy and sleep behaviors have adapted to match their lifestyles.
Why Don’t Birds Fall Off When Sleeping While Perched?
Birds have some remarkable adaptations that allow them to snooze while perching without toppling over:
- Toe-locking – Tendons allow birds to tightly grip branches while asleep.
- Balancing muscles – Even while sleeping, birds use leg muscles to maintain balance.
- Lightweight – Birds’ hollow bones and feathers make them very light.
- Partial clavus closure – Some birds can partially close the opening to each eye for unihemispheric sleep.
- Alarm responses – Slight winds or jostling will awaken a perched sleeping bird.
Together, these mechanisms allow birds to remain safely anchored to a branch even as they cycle between sleep and brief waking periods throughout the night.
Do All Birds Build Nests to Sleep In?
While many birds do build intricate nests for sleeping and raising young, others do not actually construct nests themselves:
- Cavity nesters like owls and woodpeckers nest and roost inside natural holes or excavated cavities in trees.
- Cliff-dwellers like eagles may night-roost on bare cliffs or bluffs where they are protected from above.
- Seabirds like albatrosses often come to land only to mate and incubate eggs. They may sleep while floating on the sea.
- Shorebirds and waders nest on the bare ground, often on just a scrape in gravel or sand.
- Brood parasites like cuckoos lay their eggs in other birds’ nests and do not build their own.
So while nest-building is common for many species, others rely on alternative strategies for sleeping safely off the ground.
How Does Light and Darkness Affect Bird Sleep?
Like humans, birds have internal circadian clocks that regulate their sleep patterns. These clocks are affected by light exposure as follows:
- Dawn triggers waking – Light at dawn cues birds to become active and forage.
- Dusk triggers sleep – Dimming light stimulates increased sleep at dusk.
- Moonlight disrupts sleep – Bright moonlight can impair sleep quality and alter timing in some species.
- Artificial light affects sleep – Light pollution from cities disturbs natural cycles of many birds.
- Equatorial species less affected – Species living near the equator show weaker responses since light cycles are minimal.
So birds rely on environmental light cues to help maintain healthy, synchronized circadian rhythms and sleep-wake cycles throughout the year.
Do Birds Suffer From Lack of Sleep?
Birds do need adequate sleep to stay healthy. Researchers have found that prolonged sleep deprivation leads to detrimental effects in birds such as:
- Impaired cognition and motor control
- Increased aggression between conspecifics
- Decreased immune response
- Reduced growth in nestlings
- Inability to maintain body temperature while sleeping
- Possible accumulation of oxidative damage
So like humans, birds must get sufficient sleep to avoid both physical and mental declines in performance and health.
Conclusion
In summary, birds have evolved an amazing variety of sleep adaptations to fit their unique avian lifestyles. While birds sleep much differently than humans, their flexible slumber allows them to remain vigilant against predators, navigate on migrations, raise young, and adapt to environmental extremes throughout the world’s diverse habitats. Carefully regulated cycles of short, frequent sleep sessions interspersed with brief wakefulness are key to birds’ success in both elaborately feathered and unfeathered forms.
References
- Lesku, J. A., Meyer, L. C. R., Fuller, A., Maloney, S. K., Dell’Omo, G., Vyssotski, A. L., & Rattenborg, N. C. (2011). Ostriches sleep like platypuses. PloS one, 6(8), e23203.
- Rattenborg, N. C., Voirin, B., Cruz, S. M., Tisdale, R., Dell’Omo, G., Lipp, H. P., Wikelski, M., & Vyssotski, A. L. (2016). Evidence that birds sleep in mid-flight. Nature communications, 7, 12468.
- Aulsebrook, A. E., Jones, T. M., Rattenborg, N. C., Roth, T. C., & Lesku, J. A. (2020). Sleep ecophysiology: Integrating neuroscience and ecology. Trends in ecology & evolution, S0169534721001203.
- Van Hasselt, S. J., Riccardi, E. S., Vyssotski, A. L., Lesku, J. A., & Rattenborg, N. C. (2021). The timing and function of REM sleep in bobolinks, Dolichonyx oryzivorus: a bird that does not sleep in flight. Animal behaviour, 175, 149-158.