Developers driving swifts from our skies

Population of migratory bird falls after loss of suitable nesting places, survey

Home Sweet Home is not just for humans. Swifts, the rapidly declining birds of the high summer skies, are overwhelmingly dependent on houses for nesting sites, a survey has found.

More than 75 per cent of the birds were found to be nesting in people's homes, during a survey carried out across Britain by the Royal Society for the Protection of Birds last summer.

The RSPB believes that home and business owners, builders and developers can play a fundamental role in protecting the species, a summer visitor from sub-Saharan Africa which has plunged in numbers in recent years. Swift populations fell by 47 per cent between 1994 and 2007.

The traditional nesting site for the swift is on a beam under the eaves of a house. But due to properties being renovated and improved these sites are disappearing – a trend which may be playing a significant role in the bird's decline in Britain. The RSPB and swift conservation groups will now be seeking to speak to developers, local councils and building companies about how they can help retain or replace nest sites.

Other migrant birds, such as turtle doves, nightingales and wood warblers, are also shrinking dramatically in numbers for reasons which are not clear.

The survey, which checked nest sites at more than 3,400 locations, and for the first time recorded exactly what sort of buildings the birds were using, found that they much prefer to nest in older parts of towns, under the eaves of older housing stock.

Of the houses swifts were using, more than half were built before 1919, while exactly a quarter were built between 1919 and 1944. More than half had been known swift nesting sites for more than 10 years, and almost a fifth were considered threatened.

Almost 5 per cent of swifts were recorded in churches, proving that old buildings prove ideal nesting sites. Many churches are undergoing preservation work which could unintentionally cause the loss of nesting sites, so church groups can also play a role in helping the birds, the RSPB says. The remaining 20 per cent of swifts were in buildings such as schools and flats.

If you have swifts nesting on or near your property, you are unlikely to miss them, because on summer evenings the birds gather in "screaming parties" and swoop low around the area uttering wild cries.

"The scream of the swift marks the start of the summer for many people," said Sarah Niemann, RSPB species recovery officer. "To think that we are losing them at such a fast rate is devastating. It was imperative that we find out exactly where they nest in the UK so that efforts to help them can be effectively targeted. This is the first time we've had swift data available on this scale, and it's a great start.

"Now we want to continue building these records, which will make a huge difference to the future of swifts in Britain."

Emma Teuten, RSPB Data Management Officer, said that mapping the results had been a massive undertaking: "They will enable us to do even more work to halt the swift's decline and enthuse people to help the birds, such as those who actually have them living close by, or may be planning work that could affect existing nest sites," she said.

"These are birds that don't touch down for two years or more after they leave the nest, and we need to ensure they have a safe, secure site to settle in when they come down to breed themselves. Swifts are very site faithful, so once they move in, then the same site may be used for many, many years."