The devil’s birds reveal their tender side | Environment

The wall next to Clifton Down train station is alive with the sounds of spring; the blackbird’s bubbling song, bees buzzing and the chirping of tiny tits hiding in the ivy. But sitting outside a bar with a pint of cider I’m willing it to be summer already. I’m trying to block out the commuter traffic and gossiping students to listen for a sign that the next season is on its way.

The sky is an obliging cornflower shade and the sun shines honey-coloured through my glass but the breeze is bracing. It has driven the resident swifts up beyond my hearing. A pair circle high over the shopping centre, two thin black crescents in the perfect blue sky.

The next day dawns bright and calm and I’m visiting Bristol’s premiere swift saviours (bristolswifts.co.uk) out in the suburbs. The wind has dropped and so have the birds. They race around the side of the house, screeching as they speed past a row of purpose-built nesting boxes. The white oblongs look like static caravans suspended under the eaves and in a sense this is an aerial holiday park: the swifts are here for the local cuisine and to find romance.

Mark and Jane Glanville’s feathered guests arrived at the start of the month having completed a staggering 5,000 mile non-stop journey from southern Africa. Staggering is all they can manage on their underdeveloped legs when they first return because they spend so much of their life on the wing. Hidden nest cameras show the swifts crashing about but they reveal something gentler too. Reunited with their long-term partners, adult birds indulge in tender preening to reaffirm their bonds.

Such intimate insights weren’t available in the middle ages when swifts’ high-pitched, screaming whistles and aerial acrobatics earned them the nickname “devil’s birds”. Now, however, advocates for these devils are recruiting. After years of evicting wildlife to keep our homes airtight, Bristol’s residents are being encouraged to welcome swifts back to roof spaces – or at least nest boxes – so we can listen for these heralds of summer in the city sky for years to come.

Twitter @Jaylikethebird