Wondering when to clean out bird nest boxes in your garden? Autumn is the ideal time to give boxes a safe, thorough clean, boosting the chances they’ll be reused next spring. Clearing away old nests removes harmful parasites and helps protect future chicks. In this quick guide, we’ll explain when, why, and how to clean bird boxes properly, plus tips to encourage winter roosting.
When to Clean Out Bird Nest Boxes - and Why it Matters
Cleaning out bird boxes at the right time of year gives garden birds the best possible chance for a healthy breeding season. It helps remove parasites, keeps disease at bay, and gives hatching chicks the best possible start in life.
While many birds will reuse nest boxes, cleaning nest boxes annually greatly increases the chances of them returning, by removing old nest materials, dirt and detritus, and helps reduce harmful parasites and mites that build up over time.
Why Clean Nest Boxes After Breeding Season?
Birds naturally clean out nest boxes a little before reusing them, but it’s not always enough. A proper deep clean can:
- Remove harmful parasites like fleas and mites
- Reduce the risk of disease transmission (including Salmonella and avian flu)
- Improve nest box longevity and insulation
- Encourage birds to reuse the nest box next year
Why Timing Matters
- October–November is ideal: birds have vacated, and legal window opens
- Clean nest boxes may be used for shelter and warmth by birds during cold winter spells
- Avoid spring cleaning to prevent disturbing early nesters
When to Clean Bird Nest Boxes (UK Timing)
October and November are the best months to clean a nest box in the UK. This is when birds have typically finished breeding, and you can legally remove old nesting material.
Key Tip: Under the Wildlife and Countryside Act 1981, you may only remove unhatched eggs between 1st October and 31st January, and they must be destroyed, it’s illegal to keep them.
Avoid cleaning in spring or summer, as this can disturb active nests and cause nest abandonment. It is also illegal if eggs or chicks are present.
How to Clean a Bird Nest Box (Step-by-Step Guide)
Knowing how to clean a nest box safely is just as important as knowing when to do it. Here’s a simple step-by-step method:
- Wear gloves and remove all used nesting materials* (if there are unhatched eggs or dead in the nest see note below)
- Clean using boiling water to kill any remaining parasites and their eggs. You may also want to use a specialist bird safe disinfectant such as Ark-Klens. Insecticides and flea powders must not be used
- Allow sufficient time to dry thoroughly before replacing the lid. Do not use any wood preservatives, fumes get trapped inside the nest chamber and may be toxic to birds
- You can place a small handful of dry leaves, wood shavings or hay (not straw) in the box after it’s cleaned and dry because nest boxes may well get used for roosting during cold winter snaps by small birds such as tits or wrens
Top Tip: Use a nest box with hinged sides for easy cleaning and inspection.
Additional Notes.
It is not unusual to find a small number of eggs that have failed to hatch, or some young that have died. Blue and great tits may lay over a dozen eggs to allow for such losses. Sudden cold snaps, food shortage, predation or simply inexperience can all lead to complete nest desertion, or limited survival rates.
Don’t worry if your nest box wasn’t used this year, it may attract an occupant next year. Take it down, check it and clean as required but put your box back up as it may provide a useful roost during the winter months. To increase the likelihood of your nest box being used next year, ensure you have the correct bird nesting material.
Nest boxes in use should not be inspected. Simply watch and enjoy the activity from a distance. If you want to see the chicks as they grow, consider installing a nest box camera.
Annual cleaning should only be carried out at the end of the breeding season, from late September to late January.
Under the terms of the Wildlife and Countryside Act 1981, if unhatched eggs are found in the box, they can only legally be removed from October to January inclusive, and they must be destroyed – it is illegal to keep them.
Should I Remove Old Nests from Bird Boxes?
Yes - you should always remove old nesting material once you’re certain the birds have gone. Leftover nests can contain ticks, fleas, mites, old food, droppings, and sometimes dead chicks or unhatched eggs. All of these can be hazardous to the next brood.
If you find a complete nest with nothing inside, place it in a quiet corner of your garden rather than the bin, these will still support other wildlife.
Top Tip: Bumblebees like building their nests in abandoned bird and mouse nest material. An unused bird nest makes a perfect new home for bumblebees!
Should I Put Anything inside the Box After Cleaning
Birds will happily build their own nests, often removing any material you’ve left. But adding a little dry nesting material such as our nest box starter material, hay, wood shavings or leaves after cleaning can help during cold spells when small birds like wrens or tits use the box to roost overnight.
Nest Box Cleaning FAQ's
When should I clean a nest box in the UK?
Between October and January. This avoids disturbing nesting birds and is the only legal time to remove old eggs.
Do birds reuse nest boxes?
Yes, many garden birds, including blue tits, great tits, and sparrows, will reuse nest boxes, especially if they’ve previously bred successfully. Cleaning the box between seasons reduces parasite risk and increases the chances of reuse.
Should you clean out nest boxes every year?
Yes. Annual cleaning ideally in autumn (October–November), removes parasites and old nesting debris. It also prepares the box for winter roosting or early spring nesting, improving bird health and box longevity.
How do you clean a nest box safely?
Remove all material, scrub or rinse with boiling water or a bird-safe disinfectant, then let it dry fully before reassembling. (See our step-by-step guide and video above).
Can I leave material inside for roosting birds?
Yes, by adding clean, dry wood shavings, leaves or nest box starter materials helps wrens, tits and other birds using nest boxes during winter to stay warm on cold nights.
What if I find unhatched eggs or dead chicks?
Unhatched eggs or dead young can legally be removed and destroyed only between October 1st and January 31st.
Can I use flea powder or insecticides?
No, these chemicals are dangerous to birds. Only use boiling water or a safe disinfectant like Ark-Klens.
What do I do, I found unhatched eggs in my nest box?
If unhatched eggs or dead chicks are found in a nest box, these should be disposed of between October and January. Outside this window, it’s illegal to disturb any nest containing eggs or chicks. It is also illegal to keep any wild bird egg, they must be destroyed.
Do self-cleaning pigeon nest boxes exist?
No, not for garden birds. They do for pigeon lofts or dove cotes, but not for typical UK garden birds due to excessive cost.
Can I keep the eggs left in a nest box?
Under the terms of the ‘Wildlife and Countryside Act 1981’, if unhatched eggs are found in the box, they can only legally be removed from October to January and they must be destroyed. It is illegal to keep them.
Final Tip
Even if your box wasn’t used this year, clean it and put it back up. Bird boxes are often used for winter roosting, and a clean, dry shelter can make all the difference for small birds in the colder months.
And if you want a glimpse into the secret world of nesting birds, consider installing a nest box camera, it's a brilliant way to get close to the action without disturbing nesting birds.
