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Do Birds Use Birdhouses in Winter? Yes — as Roosts, Not Nests

Birds shelter in boxes overnight through winter, sometimes a dozen at once. Why you should leave boxes up, and the two changes that make one a better roost.

By Zakaria 4 min read Save to Pinterest — opens Pinterest in a new tab
A weathered multi-hole birdhouse on a post, roofs capped with snow and icicles
Photo: dsgetch, CC BY 2.0, via Flickr
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Yes — and it is one of the better arguments for leaving boxes up year-round. Birds do not nest in winter, but cavity nesters absolutely roost in boxes overnight, sometimes a dozen of them crammed into one.

Who uses them

Winter roosting, by nesting style
SpeciesRoosts in a box?
Chickadees, titmiceYes — among the most frequent users
NuthatchesYes
WrensYes
BluebirdsYes, and famously communally
Downy woodpeckersYes — they also excavate their own roost cavities
House sparrows, starlingsYes, often to the exclusion of natives
Screech owls, kestrelsYes, in appropriately large boxes
Robins, cardinals, finchesNo — open cup nesters. They use dense evergreens

The dividing line is the same one as in spring. A bird that nests in a hole will shelter in a hole. A bird that builds an open cup in a shrub will shelter in a shrub.

Why it matters so much

A small bird’s problem in winter is not really food — it is the night.

  • A chickadee weighs about 11 grams and can lose a substantial share of its body weight overnight.
  • Small birds have an enormous surface area relative to their mass, so they shed heat fast.
  • Many species drop into regulated overnight hypothermia, letting body temperature fall by 10°C or more to save energy.
  • Wind is worse than cold. An out-of-wind cavity is worth more than a few degrees of air temperature.

A box turns an exposed 14-hour night into a sheltered one. Huddling multiplies the effect: birds packed together share heat and sharply reduce the exposed surface of each individual.

The dozen-bluebird box is real

Communal winter roosting in bluebirds is well documented, with reports of ten, a dozen and occasionally more birds in a single box on a hard night. It is one of the more striking things a box owner can witness — and one of the clearest reasons not to store boxes in the shed over winter.

Roost box vs nest box

The design differences
Nest boxRoost box
Entrance holeNear the topNear the bottom — heat does not pour out
VentilationGenerous — summer heat is the riskMinimal — draughts are the risk
Drainage holesYesYes, but fewer
InteriorBareStaggered perches or dowels for stacking
SizeSpecies-specific and snugUsually larger and thicker-walled
SeasonSpring and summerAutumn through winter

Converting a box you already have

Worth twenty minutes in autumn, after the clean-out:

  1. Block the ventilation gaps. Tape, foam strip or a thin batten along the summer vents under the roof. Reopen them in spring.
  2. Add two or three perches inside, staggered at different heights below the hole — short dowels or roughened offcuts screwed into the side walls.
  3. Check it is watertight, and that the roof overhangs enough to keep rain out of the hole.
  4. Face it away from prevailing wind and rain — in most of North America and Britain, that means pointing east or south-east.
  5. Leave the floor bare. Do not add bedding: it holds damp, and damp is far more dangerous than cold.

What you cannot easily fix is the hole at the top, which is where the heat goes. A converted box is a real improvement; a purpose-built roost box is better still.

The one maintenance job

Clean each box once a year, at the end of the breeding season — late summer or early autumn.

  • Remove all old nest material, which harbours mites, fleas and blowfly larvae
  • Scrape it out and rinse with hot water, or a very dilute bleach solution
  • Dry it fully with the lid open before closing it up
  • Gloves and a mask, because old nests are dusty and full of droppings

Do not open boxes in midwinter

Checking a box on a cold night means flushing roosting birds into the dark, which can be fatal for a small bird that has already spent the day building the energy reserve to survive until morning. Do the inspection and the cleaning in autumn, then leave the box alone until spring.

What else helps through winter

  • Leave the dense evergreens and the brush pile. They shelter every species that will not use a box.
  • Keep feeders stocked and clean, especially at dusk — birds top up before roosting.
  • Provide open water. Drinking and bathing water is harder to find than food in a freeze, and a heated bath or a simple daily refill does a lot.
  • Do not tidy the seed heads and grasses until spring. Cover and food in one.

Common questions

Do birds use birdhouses in winter?

Yes, but as overnight roosts rather than nests. Cavity-nesting species such as chickadees, titmice, nuthatches, wrens, bluebirds, downy woodpeckers and screech owls shelter in boxes on cold nights, and several birds will sometimes pack into one box together to share body heat — bluebirds have been recorded a dozen or more to a box. Leaving boxes up through winter therefore does real good, and taking them down removes shelter at the hardest time of year.

Should I take my birdhouses down for winter?

No. Leave them up. A box that sits empty all summer may still save birds on a January night, and there is no benefit to storing it — weathering is slow and a box will last many seasons outdoors. The one job worth doing is a single clean-out at the end of the breeding season, in late summer or early autumn, so the box is free of old nest material and parasites before the roosting season starts.

How is a roost box different from a nest box?

A roost box is built to hold heat rather than to raise a brood. The entrance hole is near the bottom instead of the top, so warm air is not lost straight out of it; the interior has staggered perches so several birds can stack up inside; ventilation is reduced rather than maximised; and the whole box is usually larger and thicker-walled. A standard nest box still gets used as a roost, but a purpose-built one holds noticeably more heat.

Can I convert a nest box into a winter roost?

Partly, and it is worth doing. Block or tape over the summer ventilation gaps to cut draughts, add a couple of staggered perches or dowels inside below the hole, and check that the box is watertight and facing away from prevailing wind and rain. What you cannot easily change is the hole position at the top, which is where most of the heat escapes — so a converted box helps, but a purpose-built roost box helps more.

When should I clean out a birdhouse?

Once a year, at the end of the breeding season — late summer or early autumn — and before the roosting season. Remove old nest material, scrape the box out and rinse it with hot water or a very dilute bleach solution, then let it dry fully with the lid open. Wear gloves and a mask, since old nests carry mites and droppings. Do not clean boxes in midwinter: you would be evicting roosting birds into the cold for no reason.

Which birds roost in boxes in winter?

The same cavity nesters that use them in spring: chickadees, titmice, nuthatches, wrens, bluebirds, house sparrows, starlings and downy woodpeckers, plus screech owls and kestrels in larger boxes. Species that build open cup nests — robins, cardinals, finches — never use a box in any season, and shelter in dense evergreens and thickets instead.

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