Wing & a prayer
After flying 14,000 miles, swifts are returning to their nesting sites in Scotland. These remarkable birds have been declining in numbers, but with a little help, they can thrive again, writes author Sarah Gibson
Every summer swifts bring us three months’ joy, scything over rooftops in screaming groups, stirring wonder and excitement. As swifts return to Scotland’s skies, they will have been on the wing continuously for nine months, eating, drinking and sleeping in the air without touching tree, roof or ground. They are perfectly attuned to the opportunities of an aerial life. Insects and spiders whirled up into the sky provide their food, while wind-tossed feathers, hay and tree seeds are snatched from the air to make their nests. At dusk they rise thousands of feet into the air, alternately gliding and flapping their wings, while one half of their brain sleeps and the other half stays alert.
Now, across Europe, swifts are arriving back to do the one thing they cannot manage in the air – to breed and raise the next generation. Long daylight hours and plentiful insects bring good chick-feeding opportunities and swifts breed as far north as Lapland. They will have flown some 14,000 miles since leaving for Africa late last summer, sky-wandering over rainforest, rivers and savannah in search of insect prey, including flying ants and swarming termites. In Scotland they start arriving in early May and their numbers will continue to increase as immature birds return over the next couple of months. They are widespread across towns, villages and cities but less abundant in the wetter west and far north.
Look up!
Scan the sky overhead and you may see them with their long, dark wings, scouring the skies for insects. Listen too, for their distinctive cries: an earsplitting screech when heard close-by but a silvery ringing from a distance. To breed they swap the boundless freedom of the sky for a small, dark hole in a building. You see them darting, quick as an arrow, into holes under the eaves of buildings or into crevices in the walls of churches, old factories, warehouses and castles in cities, towns and villages. Few swifts now nest in natural habitats in Europe; they have adapted overwhelmingly and very successfully to human architecture.
Most swifts will not breed until they are four years old but in their second and third summers they journey to their future breeding grounds to find a mate and secure a nesting hole. And they will start to shape their nest into a little dish-like structure, gluing together with saliva the feathers and other materials they catch in the air. The exact location of the hole is stored, map-like, in their memory and they return to reclaim it each year.
Two to three eggs are laid and both parents incubate them. Around 19 days later the chicks hatch, emerging as tiny, naked nestlings with a huge beak and an insatiable appetite. The parent birds take turns to go out and hunt, gathering a ball of food made up of 300-1,000 insects, stuck together with saliva and carried in their throats. To start with, this is divided between the hungry chicks but as they grow, they will swallow a whole ball.
Chick torpor
One of the most extraordinary adaptations of swifts is the ability of nestlings to survive periods of cold, wet weather when food is hard to come by. Unlike most birds, the young can become torpid, conserving their energy until conditions improve and insects become plentiful again.
Songbird chicks will die if no food arrives within a few hours but once they are several weeks old and have fat reserves, swifts can survive up to five days without nourishment. Meanwhile, the adults look after themselves, flying great distances to find better conditions. When the temperature warms up and food is abundant again, the parents return and the chicks rapidly catch up on weight loss.
Within the nest the growing birds start to exercise their wings, doing press-ups on their wing-tips to strengthen their muscles. Around 40 days after hatching they fly, setting off, straightaway, for Africa.
For several thousand years the relationship between humans and swifts has worked: our homes have provided the birds with places to nest. Over recent decades though, that has changed. Demolition of old buildings that housed swifts, renovation that overlooks their needs and new construction that makes no provision for building-dependent birds – all these have contributed to loss of nest sites and the relentless decline in numbers.
For example, the housing estates of the 1950s, built around Glasgow, Motherwell and Dundee, once provided swifts with plenty of nesting cavities. Constructed before the invention of plastic soffits, gaps had opened out beneath the guttering and they bred in good numbers, delighting local people with their wild, aerial displays. Then a wave of renovation swept in; the holes were sealed and the birds lost. Roof and building renovation can be swiftfriendly but rarely is.
Declining population
Swift numbers across the UK have plummeted, falling by 52 per cent in Scotland between 1995-2018. Loss of nest sites is not the only problem they are facing – crashing insect populations are also of great concern. Action is underway in several parts of the country. Tayside Swifts has been working with local people and planners for 20 years to locate, protect and map swift colonies; to install exterior nest boxes and campaign for nest bricks to be integrated into new ones.
Meanwhile, the RSPB is on a mission to turn Edinburgh into a Swift City. With funding from Scottish Power, the charity is raising awareness of the plight of swifts and working with community groups, churches and developers to get exterior swift boxes and integral nesting bricks installed. Around 60 volunteers are mapping swift nest sites around the city, in order to ensure their protection.
For the first time, this summer, the British Standards Institution will issue guidance on bird nest bricks, making it simple for builders to use them. It will recommend the ‘universal bird brick’, suitable for sparrows, great tits, starlings and swifts. Ideally, one nest brick should be installed per new dwelling. More than a hundred of these visually unobtrusive bricks are being integrated into housing in Longniddry in East Lothian, designed by Taylor Urbanism.
Further north, in Aberdeenshire, Cally Smith has set up Huntly Swifts Group to campaign for swift protection in her area. She is a passionately determined woman, working voluntarily on a fulltime basis. “I love all creatures,” she says, “but I needed a focus for my activity and wanted to do something meaningful for the planet. I fell in love with swifts and when I heard they were endangered I decided to help them.”
That first summer she identified 63 swift nest sites in Huntly, submitting her records to NESBRECK, her local biological records centre. Since then, she and her fellow group members have carried on surveying and now work with local planners to identify places where swift nest bricks should be installed. She is currently working in partnership with Swift Conservation and local builders to ensure that a former furniture store, the turreted Cruickshanks building, will retain its thriving swift colony during renovation.
To keep swifts in our lives, we all need to do something to help them. Record your sightings on the RSPB’S Swift Mapper, set up a local swift group or install a swift box on your home. And never use insecticides!
Swifts and Us, the Life of the Bird that Sleeps in the Sky by Sarah Gibson is published by William Collins in hardback, £16.99, @windsweptsarah; Useful websites: swiftconservation. org; actionforswifts. blogspot. com; nesbiodiversity.org.uk/projects/huntlyand-district-swiftgroup
Swift numbers across the UK have plummeted, falling by 52 per cent in Scotland between 1995-2018