How to make a
Natural nest holes don't come in 'standard' sizes, so please use the following sizes as a guide. Use a plank about 150 mm wide and 15 mm thick. Use the diagram to help you.
Use galvanised nails or screws. The inside front surface should be rough - this will help the young birds to clamber up. A drainage hole in the base will also help to stop the box getting damp inside.
Hinge the lid with a strip of leather or rubber (an old piece of bicycle inner tube would do). Do not nail the lid down (because you will need to clean out the box in the autumn). Instead, use a catch to keep it closed.
The entrance hole size depends on the type of bird you want to attract:
- 25 mm for coal tits, marsh tits and blue tits
- 28 mm for great tits and tree sparrows
- 32 mm for nuthatches and house sparrows
A starling box needs to be 25-30% larger with an entrance 45 mm across
If you remove the top half of the front panel, the same type of box could attract robins, pied wagtails or wrens to nest. Spotted flycatchers prefer an even shallower, open-fronted box.
Softwood boxes (such as pine) can be treated with water-based wood preservatives, such as Fenceguard or Sadolin: apply only to the outside of the box, and not around the entrance hole. Whatever you use, make sure the box dries and airs thoroughly before putting it up.
PLEASE DO NOT use chemicals like wood preservatives without an adult - they can be dangerous.
All text copyright RSPB
The RSPB’s Homes for Wildlife is an exciting activity inspiring people to transform their homes and gardens into wildlife havens by following simple, free gardening advice.
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