February 14 to 21 was National Nest Box Week. This was an event initiated by the British Trust for Ornithology (BTO) in 1997. Over many years the natural habitat has changed and the opportunities for birds to nest have diminished. Hedges were grubbed up, barns have been converted, redundant old buildings have been swept away, roofs have been made more secure and gardens have been made more tidy. So at the time when local parishes are embarking on a major Nature Recovery Project, it is appropriate to think about erecting nest boxes to help our avian friends. It is also the time of the year when they start to think about pairing up and assessing potential nest-sites.
The BTO has its own web-site on National Nest Box Week 2021 where you can find information on why put up a nest box, building a nest box, buy a nest box, where to put a nest box and which birds use nest boxes. If you want much more detail then the BTO published an excellent book in 2018 called “Nestboxes Your Complete Guide” by David Cromack, who is current chair of Peterborough Bird Club. This covers the above topics in much greater detail and has an extensive section on different species and what sort of boxes they need.
There are basically two kinds of box these days, traditional wooden ones and those made from woodcrete which are much heavier and long-lasting. Both types should be erected on a tree, wall or post in the arc from north to east if in an open area to stop the young over-heating or more towards the south-east in a wooded area to allow some warmth from the morning sun. It is also important to fix the boxes so that water doesn’t run into the opening which should be away from the prevailing winds. The opening should not be tilted upwards.
It is also important to think about predators. In addition to cats at low levels the main mammalian predators are grey squirrels, stoats and weasels which are excellent climbers, as are rats. Placing a box on a wall should deter cats but squirrels will happily climb up rustic bricks so mammalian predators are a problem. Avian predators include Great Spotted Woodpeckers and Magpies. So on wooden boxes it is advisable to buy metal plates to screw over the holes to stop woodpeckers especially from widening the holes to get at the fledglings. Birds also like to have a clear flight path to the box but also appreciate cover to provide some concealment when they are flying backwards and forwards to the nest.
One of the species that has been in steep decline is the Swift and they traditional nest in roof cavities. You can buy external boxes to attach under the eaves or internal boxes accessed via a hole through a brick under the eaves. These options are explained in detail in David Cromack’s book. Also, of course, House Martins build nests from mud under the eaves and it is now possible to help them by buying ready-made nests. Dry summers have had a consequence in recent years of there being no mud to collect so House Martins have struggled.
The various sources also give advice on maintenance because you don’t want to be cleaning boxes in winter when small birds may be roosting there to keep warm. There was an amazing record in 1969 when 61 Wrens were found in a single Norfolk nestbox.
Bird boxes are widely available in places such as garden centres but it is worth mentioning a few interesting sites. Locally, Nicholas Watts at Vine Farm at Deeping St.Nicholas stocks a wide range of boxes and if you search on his web site you will find lots of information similar to the above as well as his range of boxes. The RSPB has a good range at reasonable prices if you search RSPB Shop on their site. NHBS in Devon is a well-known supplier of all things for wildlife and they have a good range as do Garden Nature.
So, now is the time to start putting boxes up as birds think of pairing up ready for spring. You may also want to look into what sort of plants you need to increase the numbers of insects which the birds can catch to feed their young. But that’s a whole new topic.
KEITH LIEVESLEY