Swifts don’t perch. A simple fact, but one that changes everything about how we see these birds. They eat in the air, drink in the air, mate in the air, and some even sleep in the air. They come down only to nest, and when they do, their feet can barely hold them upright.

J.A. Baker watched them for years in the skies above Essex, England. In his raw, almost feverish account The Peregrine (1967), he describes their mastery of air: “They have scythe-wings that anchor them to the wind, that take their strength from it and let them rest there… They are not birds; they are the impossible made actual.”

All summer long they live Beyond our dreams, between us And the sun, like black arrows In a trance of motion— Ted Hughes, “Swifts” (1979)

These birds troubled early naturalists. Gilbert White, writing in The Natural History of Selborne (1789), puzzled over their disappearance each autumn. He noted how they would “withdraw and disappear some weeks before others” of their kind. Where did they go? White suspected they might hibernate in holes, like bats. He was wrong, but his careful observations of their habits still ring true: “They are the most wakeful, the most active, and the most swift of all sublunary beings.”

Recent tracking studies have shown that Alpine Swifts can stay aloft for up to 200 days without landing. Charles Collins, in his 1975 paper “The Black Swift” (American Birds 29:11-14), noted that these birds “represent the ultimate in aerial existence among birds.” His words echo across decades to meet modern findings that confirm what seems impossible – swifts can enter a form of half-sleep, resting one brain hemisphere at a time while continuing to fly.

David Lack spent years studying swifts from a tower room in Oxford. His book Swifts in a Tower (1956) remains one of the most detailed accounts of their lives. He describes how young swifts exercise their wings for days before their first flight, how they build their speed gradually in the safety of the nest. When they finally leave, they don’t return for two or three years. Their first flight must be perfect.

They’ve made it again, Which means the globe’s still working…
— Ted Hughes

Roger Deakin, swimming across Britain for his book Waterlog (1999), watched swifts from the surface of a lake. “They were flying so low,” he writes, “that I could hear the snap of their beaks as they caught insects just above my head.”

In cities, swifts nest in the cracks of our buildings, in the spaces we forgot to seal. Derek Ratcliffe describes in The Peregrine Falcon (1980) how they adapted to human structures, moving from cliffs to churches, from caves to concrete. “They are,” he writes, “perfect examples of wild creatures that have turned man’s works to their advantage without becoming dependent on him for food.”

But we’re losing them. The modern drive to seal every crack, to make buildings airtight and efficient, has left swifts with fewer places to nest. Their screaming parties – those wild summer evening flights around old church towers – are becoming rare in many places. David Gunnell, writing in the British Birds journal (2013), describes how swift colonies in Bristol have declined by 60% since 1980.

Yet where they remain, swifts still draw us out on summer evenings. Watch them long enough and you start to understand what Baker meant when he wrote that they are “not birds.” They are something else – a different solution to the problem of being alive. They found a space between earth and sky and made it their home.

White’s final words about swifts in his Selborne letters seem both hopeful and sad today: “While they treat us with these peculiarities, they so regularly return to their old haunts that some are known to have frequented the same chimney for a whole series of years.” We can only hope they’ll keep returning, keep scribing their black signatures across our summer skies.