Swifts are the last of our spring migrants to arrive. With the return to our skies of their dark, scythe-like shapes and screaming calls; we know summer has arrived. These extraordinary globetrotting birds spend their entire lives on the wing: making a 20,000km round trip from southern Africa to the UK to breed and find nest sites in our homes.
Swifts are entirely dependent on buildings for nesting and the Wildlife Trust survey found that the vast majority of nest sites recorded were in the roofs of houses, the birds usually obtaining access under the eaves through gaps between or under the tiles and the wallhead. By renovating our homes: repairing holes and cracks, blocking up eaves altogether, or re-roofing; the number of number of possible nest sites for swifts has declined.
Lincolnshire Wildlife Trust President, Ted Smith, said: "Evidence of loss of nest sites is perhaps the most important outcome of our survey. Our observers recorded a decline in some 46% of the places surveyed. In the absence of any previous population counts many of these observations were inevitably based on impressions, but there were a lot of them and, taken together with some of the more detailed counts of particular colonies over several years, they demonstrate convincingly that a decline has taken place. The great majority of those who answered this question attributed losses to re-roofing of houses where pantiles had been replaced by tight fitting, machine-made tiles and plastic fascias which make access to the roof space impossible.
"Like many of our other migrants out of Africa whose populations are declining, swifts may be suffering across the whole of their range from a variety of adverse environmental changes and conditions linked perhaps to climate change. In these circumstances – as our survey shows – the continuing availability of nest sites in buildings is critically important."
This is where builders, developers and individuals can help. When roofing work is undertaken at known swift sites – and it should in any case be avoided in the breeding season – access for swifts to the roof space under the tiles should be left at several points. Nest sites can also be provided by constructing hollow eaves with access holes for the birds, including specially designed hollow bricks “Swift Bricks” in building works or by putting up nest boxes under the eaves.
The Wildlife Trust’s survey has recorded swift nest sites throughout Lincolnshire, North Lincolnshire and North-East Lincolnshire but there are almost certainly more places where they occur for which there is no record. To enable a more complete picture of the distribution of swifts to be completed, the Wildlife Trust would welcome information in particular from: Haxey, Epworth, Immingham, Cleethorpes, Brigg, Gainsborough, Mablethorpe, Saltfleet, North Somercotes, Holbeach, Long Sutton, Sutton Bridge, Donnington, Stamford, The Deepings. If you are aware of swifts in any of these or other places, particularly if you’ve seen them flying at a low level or entering a roof or building, please contact the Wildlife Trust by email with the location, approximate numbers of swifts and any other information particularly about loss of nest sites.