New backyard birdwatchers have many questions about the birds they see. We often start with how to distinguish one species from another, or how to tell the male from the female. One of the next big questions many ask is “where do birds sleep at night?” Most birds tend to sleep in the areas they inhabit during the day, but other factors also determine where they sleep.
Do Birds Sleep in Their Nests?
Pictures and cartoons often depict birds huddled within their nests sleeping. This is farthest from the truth. Birds will look for several places to sleep, including unoccupied birdhouses, gutters, chimneys, and tree cavities. The one place they do not sleep is the nest. Once the bird’s offspring have left the nest, it is often unsuitable for sleeping as it is usually coated with bits of food, feces, mites, and other debris. Additionally, after the vigorous work of nurturing and raising the hatchlings, the nest is often worn through and falling apart.
Birds of a Feather Sleep Together
One important factor that helps determine where birds sleep at night is the species of the bird itself. Smaller birds often choose to sleep on tree branches higher up on the trees, safe from predators on the ground. But larger birds that are not able to land on tree branches—they’ll look for dense shrubbery to sleep in. This is true for birds in the ground-living family such as grouse, quail, partridges, and pheasants.
Birds in the passerine family (perching birds with one toe pointing backward and three toes pointing forward) usually sleep on tree branches. A tendon in the backs of their legs remains tight when their legs are bent, resulting in a curl in their toes that lets them grip their perch. This grip enables the bird to remain on their perch without falling off during sleep. Passerines tend to sleep in large flocks to share body heat, which greatly increases their chances of surviving nighttime temperatures. The most common species you might spot sleeping like this are cardinals, sparrows, and birds in the jay family.
See also: A 5 Step Plan for Nighttime Birdwatching
Weather and Changing Seasons
The change in seasons and accompanying weather conditions is another important factor that determines where birds sleep at night. Changes in seasons can also coincide with the life cycles of birds.
Breeding season is one life cycle that affects where birds sleep at night. Territorial Birds that may sleep with a community of birds during other times of the year, will become rigid in their desire to sleep in their territory or nest during breeding season. At the end of the breeding season, species that sleep in tree cavities, such as woodpeckers, will create a new sleeping cavity instead of returning to an older cavity from breeding season.
During harsh conditions, such as strong wind and rain, birds will sleep in a variety of places, like unoccupied birdhouses, tree cavities, chimneys, dense shrubbery, and any crevices where they will be sheltered until the storms pass.
Cold and snow affect where many species of birds sleep. For backyard birds like cardinals, wrens, nuthatches, and woodpeckers, the winter months can be challenging. A bird will fluff up its feathers to protect its vulnerable body parts. This creates insulating air pockets to retain body heat. Birds also tuck their feet and bill into their feathers for additional insulation. Tucked into the bird’s feathers, the bird’s bill breathes out air warmed by their body, continually keeping them warm and insulated from the cold.
Safety from Predators
The saying ‘sleeping with one eye open’ might originate from birds, as many birds do exactly that. Wherever they choose to sleep, birds are vulnerable to predators both on the ground and in the trees. Because of this, a lot of birds sleep for very short periods of time, aware of potential danger.
Birds can “turn off” one side of their brain for rest while keeping the other side turned on, remaining in a vigilant state during sleep. This ability is known as unihemispheric slow-wave (USW) sleep. Experts have determined that each eye is linked to one side of the brain, to the opposite side it is on. This enables them to literally rest the right side of the brain while the left eye is open and vice versa. While other animals can sleep this way, birds are the only animals that have control of this function. This unique feature is one of the bird’s greatest defenses during sleep.
Sleeping in flocks, also called roosting communally, offers birds greater safety while they sleep. With so many birds together, its likely more birds will notice an oncoming predator and alert other sleeping birds, giving each bird a better chance of surviving a potential attack.
See also: How Birds Learn to Identify Threats
How to Help Backyard Birds Get a Good Night’s Sleep
While some birds are nocturnal (and even sing at night), there are many species of birds that do sleep at night. You can help your backyard birds get a good night’s sleep with just a few steps:
- Set up a bird-friendly yard with sheltered areas for sleeping like native plants and roosting boxes. Clean out old birdhouses to attract birds as well.
- Keep birdhouses, roosting boxes, and feeders out of their reach from stray cats and camouflaged by native plants.
- Keep your birdfeeders filled with fatty food sources such as sunflower seeds, suet, millet, and nyjer seeds to help them build energy stores for inclement nights.
- Turn off any outdoor lighting in your yard so as not to disrupt their natural sleep patterns. Birds’ internal clocks follow the dark and light cycles, and your brightly lit yard might interfere with their sleep.
Learning how and where birds sleep is yet another fascinating subject for birdwatchers. Take a pair of binoculars and step out into your backyard tonight and see if you can spot a few of your backyard birds catching some Zs.