There are two main considerations when siting a nest box: first, you must choose an appropriate nest box for the specific species of bird you wish to attract; and secondly you must find the right location in your garden for the box. If you’re attracting Tits, Sparrows or Starlings, for instance, it is essential to locate the box two or four metres up a wall or tree. Robins and Wrens are slightly different, as nest boxes for these species are better lower down, below 2m, well hidden amongst protective vegetation, and have open fronts. Woodpeckers will need a box located between 3m and 5m on the side of a tree.
Predators can be a possible risk factor, as cats, being nimble climbers, could potentially access your nest boxes. Make sure you site your box in a location safe from cats (and squirrels, which can be deterred using a metal hole around the entrance).