Quirky, attractive and elaborate bird boxes are not necessarily safe or effective for nesting birds, the RSPB is warning.
In some cases, unsuitable nestboxes made with the wrong material or a poor design could lead to injury and even death.
Gardeners around the UK will put up nextboxes this month in good time for the breeding season. The RSPB is asking that they make sure the ones they choose are the right size, shape and material.
Boxes shaped like caravans, farmhouses, eggs, windmills and even fruit are on sale as nesting sites for garden birds. But although they might make a quirky feature in your garden, they could actually be dangerous for young birds.
Many are made from materials that also look attractive, but are completely unsuitable for nesting birds – such as ceramics which are not good for insulation or brightly coloured materials which do not make the box inconspicuous to predators.
Nestboxes with metal roofs retain too much heat and can literally bake baby birds to death on sunny days. Metal and plastic nestboxes suffer from condensation causing baby birds to get damp and cold.
Ian Hayward, RSPB Wildlife Advisor, says: “There are so many elaborate nestboxes on sale that look the part but are really quite dangerous to nesting birds. Don’t be tempted to go for the unusual shapes and colours – traditional, wooden nestboxes really are the best – and often the most cost effective too.
“Nestboxes are out in all weather so they need to be strong, robust, waterproof and have good insulation. They also need to have the correct hole size.
“People tend to forget that a nestbox will eventually contain tiny helpless, vulnerable baby birds and the appearance of the box should be the last thing on your mind.”
The RSPB is suggesting some nestbox dos and don’ts:
They should:
- Be robust – they are out in all weather and need to be strong and fit for purpose
- Be waterproof – they need to be treated with a water-based preservative
- Have the correct hole-size – if too large predators will easily get inside and rain/wind will get into the box
- Be safe – no dangerous sharp edges, protruding nails or staples or unecessary fixtures or small gaps which may harm or trap birds
-Have good insulation – wood or woodcrete is usually the best material
- Have no perches
They should not:
- Be brightly coloured – the more inconspicuous the better
- Be made from flimsy material – many boxes fall apart when any weight is put inside
- Be too shallow – young birds could leave prematurely by falling out
- Be too deep - young birds may have problems getting out when they are ready
- Be too smooth on the inside – slippery material will also make it difficult for young birds to get out
- Have gaps – rain and cold air will get in and cause young birds to get cold and damp
The RSPB also recommends that nestboxes are positioned where it isn’t easy for predators such as cats to access them and where there isn’t too much sunlight.
They should be cleaned out each autumn and have fresh hay or wood shavings added as a potential winter roost site.
To find out more about nestboxes and where to site them visit www.rspb.org.uk. To order a variety of nestboxes tried and tested nestboxes visit www.rspbshop.co.uk