Help and Advice - Nest Box Preparation for Wild Birds

As early as January, the birds in your garden will be thinking about the nesting season.

This January 14th, we had a mild day, and from the first morning song it felt like spring was just around the corner. Now I can’t say if it is due to climate change, but the birds are preparing earlier each year, and this means we have some jobs to do in order to attract the birds to our gardens.

First job is to clean out last seasons’ nest box, and this should be done in early, to mid January. There are lots of types of boxes, but generally the principle is the same. Gain entry to the nesting area, by lifting the lid, or opening the front / back or unscrewing a section. This is a good time to point out the importance of selecting an easy access nest box, because some can be really awkward to clean. I always prefer the lid hinged, as this allows the box to be tipped up and shook empty.
Before putting your hand into a nest box, have a look to check there is not already an occupant. Not only birds use the boxes, and you might get a shock if a door mouse is curled up asleep!
It is best to put on some gloves, and remove the old nest in one handful. The old nest wants to be disposed of, either in the recycle dustbin, or incinerated. I avoid putting it in the compost heap, as it may be used as material for new nests and that can spread disease.
Next, take a stiff bristled brush (I usually have an old paint brush that is past its best) and brush out all the debris from the box. Check that mould is not present, and replace the box on its site.

If there is mould in the box, then you need to take the box and really give it a good scrub, inside and out. Use a mild detergent or a specific nest box cleaner. Then leave it in a dry, but airy place and let it dry thoroughly, this may take a few days, but the box needs to be thoroughly dry inside, before being replaced back to its site. The chances are that if mould was present, the inside of the box is just too well draft proofed, and this has allowed moisture to sit and go mouldy. In this case, drill 5 holes, each 2mm in diameter in the corners and centre of the base; this should prevent a recurrence of mould.

If you treat the external wood of your nest box, do so as early in the winter as possible, and leave outside, to allow the odour to recede. I never treat the inside of a nest box.