Cleaning Out Bird Nest Boxes and Adding a Winter Roost Box

Clean out bird nest boxes after the last brood has fledged and the box is empty, usually in late summer or autumn, by removing old nesting material, scraping out droppings, and letting the box air dry. Then either leave the box up as a winter shelter or add a dedicated roost box, which has its entrance near the bottom and perches inside so small birds can huddle together on cold nights.

Why clean nest boxes at all?

Old nests can hold mites, fleas, blowfly larvae, and mold. Birds often build on top of old material, which raises the nest closer to the entrance hole and makes it easier for predators to reach eggs and chicks. A clean, dry box also attracts winter roosting birds such as chickadees, titmice, wrens, nuthatches, and bluebirds.

Important: never disturb an active nest. In the United States, nests, eggs, and young of most native birds are protected by federal law. If you see eggs, chicks, or adults carrying food, wait. Many species raise two or more broods, so check that the box has stayed empty for a couple of weeks before cleaning.

Safety while cleaning

• Wear disposable gloves and a dust mask. Dried droppings and nest debris can carry bacteria and fungal spores.
• Clean outdoors, upwind, and avoid shaking debris toward your face.
• Wash your hands thoroughly afterward, even if you wore gloves.
• Use a stable step stool on level ground for boxes mounted high, and have someone steady it if possible.
• Watch for wasps, which sometimes claim empty boxes late in the season.

Step-by-step cleanout

1. Confirm it is empty. Tap gently on the box and listen, then open the side or front panel.
2. Remove the old nest. Lift it out whole and bag it; do not leave it under the box where it can draw predators.
3. Scrape and brush. Use a putty knife and stiff brush to clear droppings and loose debris from the floor and corners.
4. Rinse if needed. Plain water works. If the box had mites or mold, use a weak solution of 1 part bleach to 9 parts water, rinse thoroughly, and let it dry completely in the sun.
5. Inspect and repair. Check drainage holes in the floor, ventilation gaps under the roof, and hinges or screws. Replace cracked panels.
6. Close it up. Leave the box empty. Do not add nesting material; cavity nesters bring their own.

Adding a roost box for winter

A roost box looks like a tall nest box with the entrance hole near the bottom, so rising body heat stays trapped above. Inside, staggered dowel perches let several birds pack in together.

• Mount it 8 to 12 feet up on a pole or trunk, facing away from prevailing winter winds, often south or east.
• Choose untreated wood at least 3/4 inch thick, with ventilation that can be closed for cold months.
• Pair it with a nearby food source such as suet and winter feeders and an open-water source like a heated bird bath.
• Use a squirrel baffle on the pole so climbing predators cannot reach the box.

You can also convert a regular nest box for winter by plugging summer vent gaps with weatherstripping and adding a small amount of dry wood shavings in the bottom. Remove the plugs and shavings before nesting season.

When to put boxes back in service

Reopen vents and remove any winter additions in late winter, before early nesters start scouting. In milder regions, some birds begin checking boxes surprisingly early, so having them clean and ready ahead of time matters more than waiting for warm weather.

Bottom line

Clean nest boxes only after they are empty, wearing gloves and a mask, then leave them up or add a roost box with a low entrance and interior perches to shelter small birds through cold nights. Pair shelter with food, water, and predator guards for the best results.

Related reading

• Winter bird feeders and suet
• Heated bird baths for winter water
• Squirrel baffles for feeder poles

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