Thinking of putting up a nesting box in your garden, then British Trust for Ornithology and the RSPB warn that, while some boxes provide a perfect breeding cavity for birds, others may be far from ideal.
You may be tempted to buy eye-catching brightly coloured nest boxes and quirky types shaped like caravans, farmhouses, eggs and windmills, but the RSPB warns that attractive and elaborate bird boxes aren’t necessarily safe or effective for nesting birds.
What makes a successful nesting box?
So, what should we be going for? The BTO offers the following guidelines:
1. Make sure it’s insulated
Only choose a box made from an insulating material such as wood or a special waterproof wood/concrete compound like Woodcrete. This has been used for the National Nest Box Week ‘official’ box before.
2. Avoid metal and ceramics
Don’t choose a box made from dense materials like metal or ceramics as the interior can become too hot or too cold for chicks to survive. Nest boxes with metal roofs retain too much heat and can have fatal effects for baby birds on warm, sunny days.
Metal and plastic nest boxes also suffer from condensation causing baby birds to get damp and cold.
3. Choose a type with thick walls
To provide insulation and be durable, the walls of wooden boxes should be at least 15mm thick. Wooden boxes can be safely treated on the outside with a preservative provided it is non-toxic and water-based.
A box made from cedar, oak or beech will far outlive one made from softwood such as pine.
4. Check the hole size
Choose a box with a 32mm entrance hole as this is the ideal size for all small hole-nesting birds such as sparrows and tits. Choose a smaller 26mm hole only if you want to restrict the box to blue tits.
The box should not be too small inside as birds may lay fewer eggs in smaller boxes. The internal floor area should at least 130 square cm (20 square inches).
6. Avoid perches
Perches are not necessary and may even act as a foothold for squirrels or weasels as they reach into the box to grab eggs and chicks.
7. Maintain easy access
A good box should provide easy access for human observers who wish to record the contents and to clean out the disused nesting material at the end of the season.
8. Place them strategically
The ideal height for a small-hole type nest box is between 1m and 5m above the ground with a clear flight path. Care must be given to make sure the box isn’t easily accessible to predators.
There are different kinds of nest boxes for different species of bird. Cavity nesting birds like nest boxes with entrance holes, and the size of hole will depend on the target species.
For example, blue tits prefer boxes with a small hole (25mm), Starlings on the other hand would need slightly larger holes (45mm). Other birds like open-fronted nest boxes, such as robin and spotted flycatchers.
9. Avoid bright colours
Steer clear of brightly coloured nest boxes. The more inconspicuous they are, the better. Make sure they are not made from flimsy materials as many boxes fall apart when any weight is put inside.
Don’t let them be too shallow as young birds could leave prematurely by falling out, and don’t let them be too deep as young birds may have problems getting out when they are ready to leave.
You may also be interested in…
Best-selling nesting boxes for wild birds
Stuck for inspiration? Check out our list of best-selling Amazon products!
- Traditional Wooden Garden Bird Nesting Box.
- Handy Hinged Lid For Easy Cleaning/Filling.
- Most Suitable for Small Garden Birds.
- SMALL BIRD HOUSE - Ideal for a variety of small wild birds such as robins , blue tits , Sparrows, great tits and nuthatches.
- READY TO USE – It can be mounted on fences, trees, posts or free standing.
- OVERALL SIZE - Height 21cm x Width 12cm x Depth Approx 13.5cm Approx Including roof.
- Suitable for many species of wild birds
- Hinged roof for easy access to clean out
- Hanging hole at the rear
- Made from FSC certified Timber
- Interchangeable fronts, 32mm hole, 28mm hole and open front make this the perfect nest box for attracting the widest variety of birds
- Floor removes for easy cleaning
- 6 x Traditional Garden Bird Nesting Boxes
- Ideal for a variety of small wild birds such as robins and blue tits
- Comes with a hinged lid
Last update on 2021-02-26 / Affiliate links / Images from Amazon Product Advertising API
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