The sky was intermittently blue and weak sunshine sparked a faint chorus of grasshoppers. Otherwise, this was a landscape wrung dry of all summer and the grasses were grey, the thistles dead, if flossed with cottony seed. The only sounds were the long-drawn notes of young buzzards that were suffused with a sense of melancholy. There were seven birds – adults and immatures – careering at one another in mock squabbles, or they would flap away with deep rhythmic wingbeats, before coming about and paddling up on the bluffs of warm air. Perhaps it was the way that their movements perturbed these rising currents, but 50 house martins and swallows circulated among them to feed, like children perhaps, playing but oblivious around the slower limbs of walking adults. It was a glorious, slow-twisting gyre of different flight modes. Then I spotted the swift. It must have been a lone Scottish breeder or a Scandinavian migrant drifted to these islands. Yet it was alone and plainly detached from the wider southward movement of its kind, much of which occurred in late July. House martin flight is beautiful and quick, and the separate strokes not easily countable, but in swifts you barely register wingbeats at all, each one swerving into the blur of the last. If an absence of straight lines defines nature, then swift flight is nature’s apotheosis. My bird jinked left and right, again and again, repeating the twists maybe seven to eight times, as if there were invisible obstacles aloft and the bird must plot a tight route through all that free air. I had to recall that with each bend of its path, some insect was also being snaffled by the bird’s immense maw. A parent can take prey like this, one after the other, until an invertebrate ball, adhering as a bolus in its sublingual pouch, can number 1,000 items. Swift flight, then, is both precise and practical, but also purer than in any other bird and watching it feed here among martins was like seeing a wolf hunt among dogs. It was a joy to savour it one last time until next spring.