Should You Clean Out Nestboxes in Your Garden?

For our garden birds, the breeding season is now over. The nestboxes in our gardens, which a few months ago were home to hungry broods of blue tits or house sparrows, now lie quiet and empty. Well, not quite empty – they will still contain the nesting material used by the previous occupants. Should you just leave it in there over the winter, or clean out nestboxes in preparation for new birds next spring?

Most garden birds in the UK prefer to make their own nests from scratch. After all, old nesting material is likely to harbour fleas and other parasites, which can remain and infest young birds that hatch the following year. The best thing we can do, therefore, is to empty the nestbox and provide a clean environment ready for the next breeding season. Bird-protection law only allows the cleaning of nests between 1 September and 31 January in England and Wales, and between 1 August and 31 January in Scotland, but even then you should take care to ensure the nest is no longer active as some birds will still occasionally be nesting in September.

Once you know that the birds have definitely fledged and there’s no further chance of new birds using the nestbox this year, you can take it down to clean it. While cleaning the nestbox, it is advised that you wear surgical gloves. Once the old nesting material has been removed, use boiling water to sterilise the inside of the box and kill any parasites that may remain. Avoid using pesticides. Afterwards, allow the box to dry out thoroughly before replacing the lid. If you find any unhatched, unsuccessful eggs in the nest while you are cleaning it out, you are required by law to promptly destroy them or throw them away. It is illegal to keep or sell these eggs.

Although you are legally allowed to clean out the nestboxes in your garden any time between the beginning of September (or earlier, if you live in Scotland) and the end of January, here at The Nature Nook we recommend that you do this procedure at around this time of year, in October or November. By now, even late-nesters will have gone and a clean, parasite-free nestbox may entice small birds to use it as a roost site during the winter months to stay warm and dry.