Putting up 70 boxes in a wood resulted in an increase in nesting pied flycatchers from a single pair to more than 20.
This year, blue tits will be particularly grateful for extra nesting sites.
According to the British Trust for Ornithology (BTO), there was a blue tit baby boom last year, and there will be a shortage of suitable nest sites for them. Building a nest box is cheap and relatively simple. All you need is a suitable plank of wood, galvanised nails or screws, a strip of leather or rubber (a bicycle inner tube will do), wire to attach the box to a tree trunk and a hammer and drill.
Building a nest box
Finding the right site for a nestbox is as important as building it. Fix it too low and cats have an easy meal; position it at the wrong angle in the wrong direction and it will let in the rain.
Boxes for tits, sparrows or starlings should be two to five metres up a tree or wall, out of the reach of cats and curious humans. Without permanent shelter provided by trees or buildings, the safest position is facing between north and east, to avoid strong sunlight and the wettest winds. Tilt the box forward slightly so that driving rain can bounce off the roof.
House sparrows and starlings will be attracted to nest boxes placed high up under the eaves. Keep these away from areas where house martins normally nest.
Open-fronted boxes for robins and wrens need to be low down, well hidden in vegetation. It's better to attach a nestbox 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. Check and adjust the fixing every two or three years to accommodate the growing tree.
Two boxes of the same kind may both be occupied if they are at the edge of adjoining territories and if there is plenty of natural food. Tits can, however, be very aggressive and seldom nest at densities greater than two or three pairs per acre.
* The BTO has updated its Nestbox Guide (pound;8.99)Tel: 01842 750 050 www.jacobijayne.co.uk
* The RSPB website has useful information on the construction of nest boxes for birds of different sizes and habitats: www.rspb.org.ukgardenswhatyoucandonestboxsmallbirdmake_a_nestbox.asp