Help us look for nature's quidditch masters

When the calendar flips from April to May, there is one wildlife thought that always comes into my mind: its Swift Time.

In some years you might see the first returning Swift in the last week of April, maybe over a southern lake swooping low. Or if the weather at the start of May is cold and blustery, it may be another few days before you spot one winging through. But of all summer migrants, this is one that always seems to arrive bang on cue.

Once that happens, summer is here as far as I'm concerned. And, astonishingly, there are barely 14 weeks until all our Swifts – and this year's offspring – have gone again, zooming their way back to Africa.

So this is the time to look up. And it's time to 'listen up', if you see what I mean, because your attention might be grabbed as much by their screaming calls as by their dark scimitar shapes dashing across the sky.

(This is as good a photo as I've got of a Swift, which I took a couple of summers ago. They are well named, so it took many attempts, panning frantically with the camera, to try and catch one in shot).

When I say 'screaming', this isn't a blood curdling screech or a 'clasp your hands over your ears' type sound. This is a 'scream if you want to go faster' call of sheer summer joy.

A couple of summers ago I had the pleasure of sound-recording Swifts as they careered through the streets of in the North York Moors village of Osmotherly. Although the odd scream could be heard during the day, it was during the warm evenings that they really got going, with groups of four, five or six birds zooming below roof height, as if playing a thrilling game of quidditch.

Sadly, that's not a sight or sound you encounter very often these days. Swift numbers are in decline, and one of the main problems seems to be that they are very attached to traditional nest holes in old buildings – if the buildings are renovated, repaired or replaced, the Swifts lose their home.

However, because this is a bird of buildings – in effect a 'house bird' rather than a 'garden bird' – it is one where its future very much sits with all of us as homeowners.

One option is to put up a Swift box, and our helpsheet here gives you an idea of what to do. I've put one up in a suitable position on my house - photo below - but it has been taken over by House Sparrows. But, hey, at least a Red-listed bird of conservation concern has found a home!

Alternatively, you may be lucky enough to move into a new house that has integral Swift boxes in the brickwork. At the flagship project at Kingsbrook, Aylesbury,  we've been working with with Barratt Homes and Aylesbury Vale District Council to try to set a new standard for wildlife friendly housing, and that includes Barratt installing hundreds of Swift Bricks, using a new design they helped develop.

And something everyone can do is take part in the national RSPB Swift Survey to help us find out where Swifts still are? What you need to look for are groups of Swifts dashing about low over the houses and those that are actually seen visiting holes in buildings, rather than birds feeding high in the sky.

You can also see where Swifts have been recorded by other people. Zoom in closer and closer on your area and you'll see it down to street level where they've been seen.

By better understanding where swifts are nesting, we can better protect them, and we can ensure that the summer skies above our homes resound to their calls for generations to come.