Locating boxes out of the reach of predators can be a challenge (weasels can climb almost anything), but there are things you can do to make it harder for them. Boxes in gardens should be located where cats cannot get to them and prickly or thorny bushes can also help to deter unwanted visitors. Some nest boxes also have anti-predator designs . It is best to avoid nest boxes that have a combined bird feeder and boxes should not be sited too close to the bird feeders in your garden. Visitors to the feeder may disturb the nesting birds and the feeder could attract unwanted attention from predators.
For many species the height of the box is not crucial. However, by placing it at least two metres off the ground you can help prevent predators and human interference. The direction of the entrance hole should be away from the prevailing wind and it is beneficial for there to be a clear flight path to the box. Crucially, the box should be also be sheltered from the prevailing wind, rain and strong sunlight, so in most UK gardens aim for an aspect of northerly, easterly or south-easterly. If possible, position the box with a slight downward angle to provide further protection from the rain. Some species do have specific requirements for where a box should be sited (e.g. house martins and swifts nests need to be sited under the eaves); please see our product details for particular instructions for different species. Wherever you position the box, try to ensure that you can still get access to it for maintenance. And finally, if possible, try to put it somewhere where you can see it, or invest in a nest box camera, so as to maximise your enjoyment of watching wild birds in your garden.
Is there anything else I can do to deter predators?
Entrance hole protection plate
As already mentioned, location is the most important factor when trying to deter predators. Whilst some mammals can climb walls, a blank wall is fairly inaccessible so can be a good choice. Ensure that the box cannot be reached by a single jump from a nearby branch or the ground.
Box design can also help deter predators. An entrance hole reinforced with a metal plate will prevent grey squirrels and some avian predators from enlarging the hole and gaining access to the nest. Deep boxes may prevent predators reaching in and grabbing nest occupants, although some tits have been known to fill up deep boxes with copious quantities of nesting material. If using open-fronted nest boxes, a balloon of chicken wire over the entrance can work well. If you live in an urban area, cats are likely to be the most common predator.