It's Time to Clean Your Birdhouses: Why, When & How

Autumn is here, which means it's time to clean the birdhouses.

Once your feathered tenants have flown south for the winter, it's time to clean out the boxes and prepare them for next year.

But why bother cleaning them at all? Don't birds prefer "natural" nests? In fact, cleaning your birdhouses can significantly improve bird health, nest success and safety when spring arrives again.

Why Cleaning Your Birdhouse Matters

According to the Cornell Lab of Ornithology, leaving old nesting material inside a box can lead to:

Parasite infestations (mites, fleas, blowflies) that harm nestlings

Bacterial or fungal growth from damp, decaying materials

Rodent or wasp takeovers during the off-season

Old nests can also trap moisture, causing wood rot that shortens the lifespan of your box. Cleaning them out ensures next year's families have a fresh, safe start.

Think of it like spring cleaning — just timed for your backyard birds.

When to Clean Your Birdhouse

The best time is after the last brood has fledged, usually in late summer or early fall (September–October in most of North America).
You'll know the nesting season is over when:

You haven't seen activity for two weeks

Parents have stopped visiting

The box looks quiet and abandoned

If you live in a warmer region where some species nest multiple times a year, check again in late winter — some birds like chickadees or bluebirds may return early.

According to the Maryland Department of Natural Resources, cleaning twice a year — once in fall, once in early spring — helps keep boxes pest-free.

What You'll Need

Before you start, gather a few safe, bird-friendly cleaning supplies:

Avoid bleach or harsh chemicals — even small traces can harm birds or linger in wood fibers. Instead, use a 1:9 vinegar-water mix for safe disinfecting.

Step-by-Step: How to Clean Your Birdhouse

Remove old nest material — Use gloves to pull out all debris and nesting matter.

Scrub the interior — With a stiff brush, clean all surfaces, including corners and drainage holes.

Rinse thoroughly — Use clean water to remove any residue.

Disinfect naturally — Pour boiling water or spray your vinegar mix inside, then rinse again.

Let it dry completely — Moisture can lead to mildew, so let it air dry in the sun before closing.

Inspect for damage — Tighten screws, patch holes, or replace worn parts if needed.

Pro tip: If wasps have nested inside, remove the nest carefully and rub a bar of soap on the interior roof — this prevents them from rebuilding next season.

Optional: Add Winter Modifications

Clean boxes don't have to stay empty! In colder climates, birds like chickadees, nuthatches, and wrens often use them for winter roosting.

You can make your birdhouse more winter-friendly by:

Adding a small layer of dry wood shavings (not sawdust)

Blocking side vents to reduce drafts

Ensuring drainage holes remain open

Facing the box south or southeast for extra warmth

This creates a cozy refuge when temperatures drop below freezing — a lifesaver during long, harsh nights.

Final Thoughts

Cleaning your birdhouses is one of the simplest and most effective ways to support your backyard birds.

It prevents disease and pests, and provides birds with a healthy place to raise their young.

As All About Birds points out, most species readily return to cleaned boxes the following season, so your efforts now will pay off in spades come spring.

So put on your gloves, make up that vinegar solution, and give your birdhouses the spa day they deserve.

Your feathered neighbours will thank you with chirps and songs — and maybe even a few new families next year!