The life and plight of a swift

PUBLISHED: 00:00 13 July 2020

A flock of swifts (c) avs_lt/Getty Images/iStockphoto

A flock of swifts (c) avs_lt/Getty Images/iStockphoto

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Herts and Middlesex Wildlife Trust’s Frieda Rummenhohl looks at the favourite summer migrant

Swifts come to the UK to breed, using the long daylight hours to hunt for food for their young (c) drakuliren/Getty Images/iStockphotoSwifts come to the UK to breed, using the long daylight hours to hunt for food for their young (c) drakuliren/Getty Images/iStockphoto

What would a British summer be without them? They are the last to arrive and the first to leave, yet they have a special place in our hearts. They are incredible aerial acrobats and spend nearly their entire lives on the wing – some will not touch down for years. Swifts are born for a life in the air, feeding in flight by catching aphids, spiders, beetles, moths and even dragonflies. They drink, bathe, mate and even sleep on the wing. 
Swifts spend most of their lives in Africa and migrate thousands of miles to England for just six to eight weeks to breed before making their way back in late July. Our British summers can be rain-soaked and even cold but they have one advantage for swifts – long daylight hours that allow these birds to hunt for 16 hours a day.
They also have several unusual adaptations that enable them to cope with the vagaries of our weather. The eggs and chicks of most small birds are vulnerable to cold, so extended feeding forays by the parents during incubation can cause the nest to fail. Swift chicks however are well adapted to being left alone in cool weather. The youngsters can become torpid – a state of lowered metabolism to conserve energy – allowing the parents to forage for food longer and further away from the nest. In the first few weeks of their lives, swift chicks also build up fat reserves and can survive several days without feeding, which greatly enhances their chances of fledging in variable weather conditions.
Once they have left the nest they will immediately begin their journey south. With a life expectancy up to 21 years, a single bird can fly more than a million kilometres in its lifetime.
Although most swifts don’t breed until their third or fourth year, the migration is deeply ingrained in their genes and young birds will make their way to the UK every summer and look for suitable nest places – without ever touching down during these years. The birds nest in crevices in walls or under roof eaves. Once an adequate site is found, the young birds pair up and start to bring in feathers, wisps of grass, tree seeds and flower sepals. If you watch closely, you may see them ‘wing-slapping’ potential nest sites to check if they are already taken. 
You can hear their piercing ‘shreeee’ call before you see them, swooping low over rooftops and chasing one other around buildings. Their apparent joie de vivre is breathtaking and has inspired many poets. Ted Hughes wrote memorably of ‘their lunatic limber scamming frenzy, and their whirling blades, sparkle out into blue’.
For thousands of years, swifts have lived alongside humans, but in the past 25 years alone, they have suffered a staggering 50 per cent decline. What has changed? Traditionally, our homes have suited them, with open eaves, loose tiles and holes in walls providing perfect nest cavities. But modern construction techniques are sealing homes off to nature and renovations of old buildings are seeing these bird-friendly features removed.
Thankfully, an inspirational movement of swift champions is coming to the rescue. Around 90 groups are taking action for swifts across the UK. Among these are groups in Tring and Hertford, running surveys to find breeding sites, working to prevent nesting holes from being blocked, installing nest boxes and sharing information with their communities. 
There are other projects too. In partnership with Herts and Middlesex Wildlife Trust, the borough councils of Stevenage and Dacorum have implemented schemes in Stevenage and Hemel Hempstead to install swift nest boxes as part of the authorities’ social housing renovations. And Herts and Middlesex Wildlife Trust’s office in Verulamium Park in St Albans will hopefully see breeding swifts in years to come, as it has installed nest boxes there too. 
To find out more about swifts and how you can help them, visit hertswildlifetrust.org.uk/actionforswifts u

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