The NHBS guide: Where to hang and how to maintain your nest box

House Sparrow Terrace FSC Nest Box
House Sparrow Terrace FSC Nest Box

With spring rapidly approaching, now is the ideal time to start thinking about nest boxes for your local birds. With this in mind we have put together some answers to the most Frequently Asked Questions (FAQs) about nest boxes – covering where and when to put up your boxes, cleaning and maintenance as well as dealing with predators.

You can browse the full range of nest boxes we sell online and if you’re keen to find out more – check out the BTO Nestbox Guide, it’s packed with essential information.

When is the best time to put up nest boxes?

Traditionally people have put up nest boxes in the early spring to ensure that they are ready for the breeding season.  However, there really is no ‘best’ time to put up nest boxes.  By putting up nest boxes in the autumn you can provide much needed winter refuges for roosting birds and increase the chance of them staying and nesting there when spring comes around.  However, any box erected before the end of February stands a good chance of being occupied.  Even after February there is still a chance of occupancy; tits have been known to move in during April and house martins as late as July.  Whatever the time of year, your nest box is likely to be used for roosting so shouldn’t stay unoccupied for long.  Therefore, put your nest box up as soon as it is available rather than leaving it in the shed!

Where should I hang my nest box?

1B Schwegler Nest Box
1B Schwegler Nest Box

When it comes to nest boxes, the ‘where’ is much more important than the ‘when’.  Nest boxes must provide a safe comfortable environment and protect their inhabitants from predators and the worst of the weather.  This may be difficult to achieve; a safe location out of reach of predators may also be exposed to the weather, so have a good think before you start bashing nails in.

Nest boxes can be fixed to walls, trees or buildings and different styles of boxes are available which are suitable for each.  Fixing to artificial surfaces means the growth of the tree does not have to be considered which is useful for Schwegler nest boxes which last for at least 20-25 years: a significant amount of time in the life of a small tree.  If you’re planning any building work, remember that some bird and bat boxes can also be built directly into walls and roofs.

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 the predator.  Boxes in gardens should be located where cats cannot get to them, making walls a better option than trees. Prickly or thorny bushes can also help to deter unwanted visitors. Some nest boxes also have anti-predator designs (e.gSchwegler’s Tree Creeper nest box).  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 several metres off the ground you can help prevent predators and human interference.  The direction of the entrance hole is also not too important but it is beneficial for there to be a clear flight path to the box.  Crucially, the box should 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.  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 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
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 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.  Schwegler’s wood-concrete boxes are too hard for any predator to break through.  However, you can also reinforce a nest box yourself with metal protection plates or provide additional protection with prickly twigs.  Not only can these prevent predators from getting to or finding purchase on the nest box, but they can also help insulate the box from the weather.  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.  An overhanging roof will also help prevent predators reaching in.  If using open-fronted nest boxes, a balloon of chicken wire over the entrance can prevent some predators gaining access, although weasels will still be able to slip through.  If you live in an urban area, cats are likely to be the most common predator.  Gardeners have long since used various methods to exclude these unwanted visitors, such as pellets, electronic scarers and even lion dung (available from your nearest obliging zoo), all with varying degrees of success, so you may want to do some experimenting.

How do I manage the nest box?

A well-designed nest box will only need one annual clean in the autumn. It is important not to clean out nest boxes before August as boxes may still be occupied.  Wait until autumn and then remove the contents of the box, checking first that the box is definitely unoccupied.  Scatter the contents of the box on the ground some way from the box to help prevent parasites re-infesting the nest box.  Use a small brush or scraper to remove debris from the corners.  Do not wait until the winter to clean out nest boxes as birds may already be roosting in them.

How many nest boxes do I need?

House Martin Nests
House Martin Nests

The exact amount of boxes required will depend on the species and the surrounding habitat.  As a very general rule of thumb, start with ten assorted small boxes per hectare (ensure uniform spacing between boxes).  Keep adding several more boxes each season until some remain unused and hopefully you’ll hit on the correct density of boxes.  However, even if you only have space for one box, remember that one box is better than no box (providing it’s suitably located).  Many UK bird populations have plummeted to worryingly low levels and they need all the additional nesting habitat they can get.

If you are interested in installing a nest box camera into one of your bird boxes, take a look at our “How to choose a nest box camera” article, for more information on choosing the model that’s right for you.

Further information about individual nest boxes, including advice on positioning, can be found alongside each nest box in our range.  If you have any other questions then please get in touch with customer services.

 

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