Where Do Birds Sleep at Night?

Where do birds sleep at night is a question with a surprising first answer: not in the nest. A nest is equipment for eggs and chicks, not a bed. For most of the year birds use a roost site instead, often the same one night after night, chosen for shelter and for safety from things that hunt in the dark.

Do birds sleep in their nests?

Only while there is something in the nest that needs them.

Audubon, publishing a BirdNote transcript, states the exception and the rule together: It might surprise you to learn that they are not snuggled into cozy nests. The only time of the year when birds sleep in nests is when they are incubating eggs or keeping their young warm. Outside that window the nest is an empty structure, and often a deteriorating one.

What replaces it is a habit rather than a building: During the rest of the year, birds select a roosting spot. Often they use the same roost night after night.

That last detail is the one worth keeping. A roost is a returned-to place, not a nightly improvisation, which means the bird at your feeder in the morning probably slept within a short flight of it and will sleep there again tonight.

So where do birds sleep at night?

In whatever their body plan makes defensible, and it differs by group.

The general case for the birds most people watch: Songbirds find a protected place to perch, sheltered from rain and safe from nighttime predators.

From there the strategies diverge. The transcript was written for radio listeners hearing each species in turn, so it names the birds as they call:

• Cavity birds share body heat. Small forest birds including this Red-breasted Nuthatch, may spend the night huddled together in tree cavities.
• The rest split three ways: Ducks float in protected bays. Woodpeckers, like this Downy Woodpecker, cling to vertical tree trunks. Crows roost communally.

A woodpecker spending the night clinging to a vertical trunk is the detail that surprises people most, and it follows from the same anatomy that lets it forage that way in daylight. Nothing about sleeping requires lying down.

How do birds stay warm at night?

Two mechanisms, one visible from a window and one not.

The visible one is posture: On these cold nights, birds fluff up their feathers for insulation and often hunker down over their bare legs and feet to keep them warm. That is the same trapped-air insulation that makes a bird at a feeder look twice its actual size on a cold morning, applied to the parts with no feathers on them.

The invisible one is metabolic, and the chickadee is the documented case. National Wildlife Federation describes it precisely: The chickadee's ability to go into regulated hypothermia enables it to actually lower its body temperature, in a controlled manner, to about 12 or 15 degrees F below its normal daytime temperature of 108 degrees F. The payoff is stated in the same passage: This allows the bird to conserve almost 25 percent of its hourly metabolic expenditure when the outside temperature is at freezing.

Biologist Susan M. Smith, who has studied the species at Cornell University and Mount Holyoke College, puts overnight hypothermia at the top of the list: Carefully hidden food items, dense winter coats, specially selected winter roost cavities and, perhaps most remarkable of all, the ability to go into nightly hypothermia, thus conserving large amounts of energy, greatly increase the chances of survival.

A note on the numbers, because they are all over the internet. Figures for how far a chickadee drops its body temperature circulate widely and disagree with each other by a wide margin, ranging from around ten degrees to claims of more than fifty. The figure used above is the one published by National Wildlife Federation alongside a named researcher and her institutions. The others are repeated without attribution, and are not averaged in here.

Note also what Smith lists second to last: specially selected winter roost cavities. The roost is not incidental to surviving the night. It is one of the adaptations.

Do birds sleep in birdhouses?

In winter, some do, and the box works better if it stops being a nest box.

A summer nest box is built to ventilate and drain. A winter roost box is built to hold heat, which means reversing most of that, and the conversion is covered in full in turning a birdhouse into a winter roost box. Cavity birds are the ones that take up the offer, which is the same group the huddling behavior above describes.

If you are going to do it, autumn is the moment, since the same visit handles the seasonal cleaning and the winter-proofing at once.

Do birds sleep standing up, and with their heads under their wings?

Standing, effectively yes. Head under the wing, no, and this one is a genuine misconception.

Audubon corrects it directly: Most birds can't tuck their heads under their wings to sleep. What actually happens is more specific and easy to see with binoculars in daylight when a bird naps: But they do turn their heads around and poke their beaks under shoulder-feathers to keep their beaks warm.

The bill is bare skin over bone, in the same category as the legs and feet, and it gets the same treatment: covered by feathers that are already attached to the bird.

Questions people ask

Where do birds sleep at night? At a roost site rather than a nest: a sheltered perch, a tree cavity, a trunk, or open water, depending on the species. Many birds reuse the same roost night after night.

Do birds sleep in their nests? Only when incubating eggs or brooding young, per Audubon. The rest of the year the nest sits unused.

Where do birds sleep in winter? The same kinds of places, chosen harder. Cavity birds huddle together inside tree holes and boxes, and Susan M. Smith lists specially selected winter roost cavities among the adaptations that get a chickadee through the season.

Do birds sleep in birdhouses? Some cavity species will roost in one in winter, especially if it has been converted from a ventilated nest box into a heat-holding roost box.

How do birds stay warm through a long night? By fluffing their feathers over their bare legs and feet, and in the chickadee's case by entering regulated hypothermia, lowering body temperature about 12 to 15 degrees below its normal 108 and saving nearly a quarter of its hourly energy use at freezing.

Do birds put their heads under their wings to sleep? No. Audubon says most birds cannot, and that what they actually do is turn the head and tuck the beak into the shoulder feathers.

Where do birds sleep at night: the short version

Not in the nest, which is scaffolding for eggs rather than furniture for sleeping. The real answer is a roost: a particular sheltered perch, cavity, trunk, or stretch of protected water that a bird returns to, chosen for cover and for what cannot reach it after dark.

On the coldest nights the work is split between posture and physiology. The feathers go up, the body settles down over the bare legs, the beak goes into the shoulder, and in at least one species that everybody with a feeder already knows, the thermostat itself comes down a dozen degrees until morning.

This article contains no affiliate links. The roosting behavior is attributed to Audubon, publishing a BirdNote transcript; the chickadee physiology to National Wildlife Federation, quoting biologist Susan M. Smith. The conflicting temperature-drop figures circulating elsewhere are deliberately not reconciled here, because only one of them comes with a name attached.