AS well as February 14 being Valentine's Day for people, it was also regarded traditionally as the date when birds pair up for the season. This is National Nest Box Week and now's the time to get bird boxes installed to encourage them to set up home.

Ready-made boxes are widely available. Jacobi Jayne Tel:01227 714314, CJ WildBird Foods Tel: 0800 731 2828 and the RSPB Tel: 0870 606 6333 all sell by mail order.

However it's easy, and much cheaper, to make your own.

Use untreated wood that is at least 15mm and preferably 20mm thick, for good insulation. Build a basic box shape with a back, floor, sides and sloping roof. If you fix it so the roof is hinged, or lifts off, then it's easier to clean out the box in the autumn.

The floor size can vary from 100mm x 100mm, just right for wrens, to 150mm x 150mm which would suit a robin.

The sides should be around 250mm high.

The design of the front is the main factor that decides which birds will be attracted. A box with a wide gap at the top can attract wrens, robins and spotted flycatchers.

Boxes with just a hole in the front will attract tits, but the size of the hole is important - 28mm for great tits, 25mm for blue tits, 32mm for nuthatches and house sparrows.

Fix the box 2m to 5m above the ground, and shelter open-fronted boxes among climbers or other cover.

February 14, 2002 15:00