Should I clean out my bird box?

Nest boxes provide vital nesting habitats for a variety of garden birds. However, during breeding season, mites and parasites can build up in the nest. If the nest is left in the box over winter, the existing mites and parasites could breed and, in large numbers, cause significant harm to future broods of nesting birds. What's more, the existence of mites and parasites could deter birds from nesting in the nest box again, so it's in our best interests to provide clean nest boxes, too!

Don't birds clear out their own nest boxes?

Some birds will clean a nest site before starting a nest, while others will use an existing nest or simply build theirs on top of it. Remember that nest-building is labour-intensive work and if there's already a nest there, there's the temptation to take a short cut and use some or all of it in nest building. However, while saving the birds time, this may not actually be in their best interests.

But we don't clear out bird nests in the wild?

In the wild, many birds make nests in holes in trees. Some people argue that we shouldn't need to clean nest boxes because nest holes in trees are not cleaned. However, it's worth remembering that nest sites in trees are more commonplace than garden nest boxes, so there's less pressure on birds to nest in the same spot in consecutive years. Also remember that trees are living beings – bird nests will gradually break down in the tree. There's some evidence to suggest the nest even feeds the tree as it breaks down. So bird nests in tree holes are self cleaning.