Swifts have been thriving for about 70 million years, when they would have been nesting in crevices in rocks and trees alongside the last of the Tyrannosaurs. But despite millions of years, something has now gone dramatically wrong, and UK numbers have plummeted in the last 25 years.
These extraordinary birds can remain in the air for three whole years because everything else apart from nesting is done on the wing. Only when they reach maturity and start to build will they touch anything solid.
No other bird can fly faster in level flight. They eat insects, drink raindrops or water from a lake, even mating and sleeping on the wing, up near Earth’s stratosphere. Their huge eyes are surrounded by bristles that act as sun visors and their feet are incredibly strong and so needle-sharp and tiny that they are unable to hop or walk, so they fly directly into the holes, cling to walls or slip into spaces where they can easily drop back out again.
Swifts originally used caves, cliffs and tree-holes for nesting, but have used man-made spaces since Roman times. Older buildings tended to have easily accessible eaves and lofts, but as these and other habitats disappear, so do the swifts. Swifts are ‘site-faithful’, so if a building has been demolished or renovated they need to find somewhere new, quickly. If an alternative site can’t be found fast, the entire breeding season is lost.
A nesting pair of swifts may need 20,000 insects a day, but widespread chemical use and habitat loss have led to crashes in insect populations. Climate change also has impacts on swifts with increased frequency of extreme weather events and disrupted weather patterns affecting their insect food as well as their own journeys.
We know via data loggers (tiny backpacks weighing one gram) that UK-bred swifts spend the winters in Africa, so we can’t save ’our’ swifts by creating nature reserves – an average swift flies 4 million miles!
Fortunately, there are now over a hundred swift community groups across the UK, including ‘Swift Cities’ and towns such as Bristol, Oxford and Harleston in Norfolk which lists swifts as, “economic drivers, social melders, educational, biodiversity indicators and activity generators”. Their spectacular aerial acrobatics and piercing screams are welcomed as signalling the arrival of an English summer.
So what can we do here?
Making insect-friendly gardens with a pond is great, and possibly more importantly, joining in this Citizen Science project to see where we need to put swift boxes. Swifts are only with us from May till early August so I would love you to log a swift diary of ‘when & where’ sightings over Horsham for the next 8 weeks or so, to help compile evidence as swifts usually nest within the same area as others and young birds research potential nest sites during May and June in anticipation of returning to breed there.
Also enjoy Swift Mapper
by Morag Warrack