National Nestbox Week is 14th-21st Feb each year – easy to remember as it starts on Valentine’s Day. This is a good time of year to put up or to clean out garden birdboxes before nesting season begins. In this post I will give some tips on servicing your bird boxes and on where to put them up.
A few weeks ago I checked and emptied some bird boxes in our Old Station greenspace in Stamford Bridge. These were put up by me over the last few years for Stamford Bridge in Bloom. One box, nearest to the Station Club building had been used in 2018 by Blue Tits, which I already knew. Sadly, upon climbing my step ladder and unscrewing the lid, I discovered that a nest and nine long-dead eggs were still present. It is always astonishing how tiny the eggs are! This is sad but not as rare as you might think. Perhaps the parent birds were killed by a cat or met some other fate? Maybe the nest was disturbed and the eggs were left cold and un-incubated for too long and never hatched?
Anyway this is an opportune moment to point out that if you have nestboxes in your garden, firstly they do need checking and cleaning annually and secondly that you may only legally remove an old nest and the eggs outside of the breeding season. In the UK this is typically March – September inclusive, though some sources recommend that you empty old nestboxes by 31st January to be sure. In UK wildlife law, the Wildlife and Countryside Act protects all wild birds, their eggs and active nests, so failed nests and eggs such as these may safely be cleared out from October – January, when there is little chance they are actively nesting. Bear in mind some species, especially Woodpigeons and Collared Doves may nest unseasonably early – so take advice if you are not sure. Another point is that it’s illegal to possess eggs of wild birds, so if you find any dead eggs, as I did, don’t be tempted to keep them but dispose of them straight away.
Last weekend I had another session when I got around to cleaning out the bird boxes in my garden. I had an empty nest (from a pair of Great Tits) to remove and another box was empty. The most fascinating was the box which was occupied last summer by wasps. The papery domed nest took up most of the space inside.
Advice on cleaning your nestboxes:
To do an annual check-up of an existing box the following steps may be helpful.
- If you can, take your box down, it will be much easier, however these instructions can be used for a box fitted in situ if you can comfortably reach it with a step ladder. (As indeed I did for the blue tit nestbox described above.)
- Pull out old nest material. If no drainage holes are present drill one near each corner with a large drill bit. Many commercially available boxes that you buy do not have drainage holes to begin with.
- Ideally, to sterilise the empty box you should pour boiling water into it, to kill bugs and pathogens. If you can do this on a fine dry day and allow the box to air before re-closing the lid so much the better.
- When dry you can make any repairs, give it a coat of water-based wood preserver if you like (outside only) and refix in place.
To put up a new nestbox:
- Ideally choose a place where the hole or opening will face between north and south-east. (This protects the nest from the worst of the prevailing weather).
- It is best to avoid south-facing locations in full sun as the box may overheat in summer weather.
- An ideal height for open front boxes is 1-2 m in dense cover, like ivy or other climbers. Robins in particular like well-hidden nest sites.
- For conventional hole boxes try a height of 2-3m. Tits and Sparrows are less particular about cover and vegetation nearby. Indeed blue tits like good visibility for danger as the emerge from the nest hole.
- If you are lucky enough to get Tree Sparrows in your garden try clustering several boxes with 28mm holes near to one another for this colonial species.
- Many birds using boxes eg Tits and Robins are territorial and so once one box will is occupied they will tend to chase off others of the same species close by.
There are no hard and fast guidelines for spacing boxes intended for territorial birds and a pair of Robins may wish to choose their preferred box from several, but bear in mind you may only get one occupied at a time.
The Sparrows are different. Both House and Tree Sparrows, their country cousins which we are lucky to see here in East Yorkshire, are gregarious colonial nesters. At some nature reserves with Tree Sparrow colonies you can see a dozen or more nestboxes clustered together and all in use. (For example RSPB reserves at Old Moor, Blacktoft and Bempton, or the Yorkshire Wildlife Trust’s North Cave Wetlands or Bank Island, Wheldrake – reserve base of Natural England for their Lower Derwent Valley National Nature Reserve.
Personally I love tree sparrows such a lot and they need help as a species so I don’t mind taking the chance of several unused boxes if there is a possibility of a colony of Tree Sparrows. So far I have had them regularly come to feeders in the garden over winter but not nesting. I have, however seen them use nestboxes in Stamford Bridge around the old station and viaduct area.