Updated: Feb 1
It was encouraging to recently hear that the new housing development in Watlington will likely include provision of nesting sites for swifts. Their low level, high speed, shrieking displays around the centre of the town are feature of our summer, when they return from overwintering in Africa. The sky above the town is rarely devoid of bird movement with kites, crows, rooks, seagulls and even the odd raven on the go higher up, and ‘garden birds’ on the move around the trees, roofs, bushes and lawns.
There are things we can do to give this ‘skylife’ a helping hand. They all need food, shelter, water and nesting sites to thrive, and now is a great time to be thinking about what we can do in gardens and around our buildings to provide the latter – by creating new nest sites and avoiding accidentally destroying the existing ones.
In this respect, our swifts are particularly vulnerable because they evolved to nest in man-made structures. They can’t really walk, so are unable to land and collect nesting materials. Instead, they are dependent on being able to swoop up into holes in the eves of buildings, shuffle to their eggs and to feed young and then literally fall back out to continue catching insects on the wing. Suitable nesting sites are limited and, unfortunately, we are hearing reports of nest sites being lost around the town as building repairs and retrofit loft insulation works are carried out that block their access. However, you can help if you want to by adding swift boxes to your house. They are communal nesters living in small colonies, so will require several boxes together and you will have to be patient as it might be some time before they are used, if at all. However, the more potential nest sites there are, the greater the chance that future generations will continue to enjoy their spectacular flights around the town.
What do birds see when they look down at us?
When a bird looks down on the town it doesn’t see houses and gardens. Instead, it sees a patchwork of small areas of woodland, scrubland and grassland, liberally interspersed with small rock outcrops with sheer cliffs on all sides, some of which mimics its wild habitat and nesting sites. Some birds need holes or crevices to line with nest material, while others can build their own structures. Most can benefit from additional provision of sites by us either by providing the basics – shrubs, trees, climbing plants, leaving thick ivy on fences - or by adding birdboxes. Also spare a thought for our jackdaws, they are naturally cliff dwellers and love taking advantage of unused chimney pots.
Although, it is the iconic upright rectangular version with a little hole in it for blue tits that springs to mind when we think of a birdbox, and is most commonly available in shops, birdboxes need to be built to different dimensions depending on the species (see photo). For blackbirds, robins and wrens they need to be open fronted, starlings need a larger hole than a blue tit, sparrows are communal nesters so need larger boxes with multiple holes or several boxes side by side. If a box is to be used, then it needs to be put up in the right location. Some birds like to nest low to the ground, others want height; all need clear flight access in and out, and most do not want to nest in direct sunlight.
Deciding what to add and where to put it is up to you. You can make provision to enhance the prospects of many different species, even woodpeckers and owls depending on the situation. If you want advice, have a look at the information available from the RSPB, BTO and wildlife trusts for starters. There are also organisations dedicated to individual species.
Cardboard mode birdboxes showing relative sizes and designs for different bird species.
If you want to buy boxes, there are specialist retailers providing the different designs needed to attract different species. For DIY construction dimensions and plans are available. With lockdown and winter upon us, now is a good time to be thinking about nest box provision, and anything else we can do in our gardens to help our skylife with food, shelter, water and nesting sites.
Eliza Naismith and Iain Naismith