Nuts about nestboxes

February half term is National Nestbox Week

Putting up a nestbox is a fabulous way to watch wildlife in your garden or local park, from noticing that the nestbox is being checked out by prospective tenants to watching the parents frantically to and fro with never ending supplies of food, to finally seeing the long awaited fledglings appear all wobbly and tentative at first, taking their first short flights.  It can be a really exciting and rewarding experience.

This week we are hosting two nestbox building sessions at Fairhaven Lake along with the Fairhaven Lake park team.  We have some pre-cut nestbox kits ready to put together and then stain.

NEWSFLASH: This event is now fully booked

These nestboxes can then be taken home or donated to the park.

But which birds are we likely to see using them and where is the best place for them to be placed?

 A nestbox is an excellent substitute for a tree hole. The species you attract will depend on the location, the type of box, and the size of the entrance hole.

How big does the hole need to be?

The entrance hole size depends on the species you hope to attract: 

• 25 mm for blue, coal and marsh tits
• 28 mm for great tits, tree sparrows and pied flycatchers
• 32 mm for house sparrows and nuthatches
• 45 mm for starlings.

Our pre-cut boxes are all cut with a hole ready for attracting tits predominantly.   However, boxes with open fronts can attract robins, pied wagtails or wrens.  These are available in the Fairhaven Lake Visitor Centre shop.

It's also a good idea to put a metal plate on the front of a tit box, to aid in minimising predation and destruction of the box.

Positioning the nestbox

• Boxes for tits, sparrows or starlings should be fixed two to four metres up a tree or a wall.
• Unless there are trees or buildings which shade the box during the day, face the box between north and east, avoiding strong sunlight and the wettest winds. 
• Make sure that the birds have a clear flight path to the nest without any clutter directly in front of the entrance. Tilt the box forward slightly so that any driving rain will hit the roof and bounce clear. 
• House sparrows and starlings will readily use nestboxes placed high up under the eaves. These birds nest in loose colonies, so two or three can be sited spaced out on the same side of the house. Keep these away from areas where house martins normally nest. 
• Two boxes close together may be occupied by the same species if they are at the edge of adjoining territories and there is plenty of natural food. While this readily happens in the countryside, it is rare in gardens, where you normally can only expect one nesting pair of any one species. The exceptions to this are house and tree sparrows and house martins, which are colonial nesters. By putting up different boxes, several species can be attracted.

How to fix the nestbox

• Fixing your nestbox with nails may damage the tree. It is better to attach it either with a nylon bolt or with wire around the trunk or branch. Use a piece of hose or section of car tyre around the wire to prevent damage to the tree. Remember that trees grow in girth as well as height, and check the fixing every two or three years.
• Open-fronted boxes for robins and wrens need to be low down, below 2m, well hidden in vegetation. Woodpecker boxes need to be 3-5m high on a tree trunk with a clear flight path and away from disturbance. 
• Nestboxes are best put up during the autumn. Many birds will enter nestboxes during the autumn and winter, looking for a suitable place to roost or perhaps to feed. They often use the same boxes for nesting the following spring. Tits will not seriously investigate nesting sites until February or March.

Avoid inspecting and going close up to nestboxes in use, however tempting it may be.  Watch and enjoy from a distance, disturbance from humans can lead to nest desertion. 

If you want to see the chicks as they grow, you could consider installing a nest box camera before the breeding season starts.

When to clean and empty the box

We recommend that old nests are removed in autumn, from September (ideally October) onwards once the birds have stopped using the box.  Please ensure the nest is no longer active, as some species can nest right through to September.

Use boiling water to kill any remaining parasites, and let the box dry out thoroughly before replacing the lid. Do not use insecticides and flea powders.

Unhatched eggs in the box can only be removed legally between September and January (August-January if you're in Scotland) - and must then be disposed of.

If you place a small handful of clean hay or wood shavings (not straw) in the box once it is thoroughly dry after cleaning, small mammals may hibernate there, or birds may use it as a roost site.  

There were once 64 wrens discovered in a winter roost inside a nexstbox!

Good luck with yours this season

Jo 

 nestbox by Andy Hay and blue tit by Matt Wilkinson (RSPB-images)