The sky is deep blue, the stonework of houses in the village faded into blocks of shadow. I don’t know why people leave their lights off at this time of day, at this time of year, but there isn’t a glowing window in the whole street. We’re all listening to and watching the aerial performance of swifts. This is the crescendo and the final act. In the coming days the stage will begin to empty and then will remain empty for ten long months. The adults and young are gathered together and using the houses to raise the stakes on their stunts, swooping low, almost skimming my hair and hurtling fast towards the walls before tilting a wingtip, flicking onto their sides and catching the little thermals that rise from the roofs which have been baking in the sun all day. Perhaps the older birds are gaping with exhaustion after these two months of furious breeding and foraging for their young. Perhaps the young, just getting to know the abilities of their long, sickle wings, but not quite strong enough yet, are sore and aching, wide-mouthed with fear as they learn to plummet dive like their parents. If that is the case, they show no sign of it. The village is a fairground with the fastest and loudest rides, and I’m watching from the quietest spot, among the tilting graves of the churchyard, beneath a glowing half-moon.

I burst into tears when I spot my first swift of the year. This is sometimes a dangerous response to a joyful occasion because for several years my first sighting has been on the motorway in rush hour traffic. They often appear low in front of me, skimming above the cars as the road crosses a bridge over the river Wye. I see that first little group of black anchor shapes, my eyes mist up and I simultaneously start laughing. It’s the acid test of the miraculous, this joint response.

I’ve always wanted to see a bee hummingbird, those tiny hovering jewels, almost impossible to imagine, but real, like tornadoes, or the three hearts, nine brains and blue blood of a giant pacific octopus. The bee hummingbird can comfortably perch on the tip of a child’s little finger. It can lay eggs in a thimble. It can drink nectar from the tiniest flowers, hovering above them while its topaz wings beat invisibly and silently. The word miracle comes from old French, borrowed from Latin, borrowed from Greek and Sankskrit. Miracle, miraculum, mirari, mirus, smeiros, smerah – which meant to smile or laugh. The word it replaced in old English was wundorweorc. Possibly I never will see a bee hummingbird, but common swifts are from the same family and they’re equally miraculous wonderworks.

The light is changing above them, all the earth’s colours turning ochre. In a few minutes the helter-skelter acrobatics will wind down and the swifts will start to climb high into the sky, two or three kilometres up. This is theoretically when they shut down half of their brains at a time, each half alternating between sleep and wakefulness during their descent, which, even at those heights does not take more than a few minutes. Their frog mouths shut, their huge eyes close one at a time, their wings lock in position for the spiralling down-slide. When a swift leaves its nest it will be on the wing for up to ten months, a period when it will only sleep for a few minutes a day, the rest of its time is spent in a fury of activity as it follows clouds of insects south across Europe and then into Africa to find the rains.

Across the street from the churchyard is the old three story house where Francis Kilvert lived while he was curate here in Clyro and where he wrote his popular diaries, volumes filled with closely observed descriptions of rural life. In the whole manuscript, over one hundred thousand words, he doesn’t mention swifts once, and only refers to swallows twice, on both occasions referring to them as a summer nuisance. In his time farms required a lot of human labour. There were many rough built houses and huts, with thatched roofs and draughty gable ends able to host nesting swifts. And there were insects in vast numbers:

“Sunday, 8 August. As I went to Church in the sultry summer afternoon the hum and murmur of the multitudinous insects sounded like the music of innumerable bells.”

This place was far more inhabited back then than it is now. Was the gentle curate less curious than he’s taken to be? How did he not find room in his diaries for swifts? He must have sat here, where I’m sitting now, with the low branches of an ancient Yew tree swaying a little in the breeze while hundreds, or even thousands of swifts plummet-dived and screeched over the rooftops. Since his day the grinding drums of industrial farming have squeezed the life from this place, so that now what I’m witnessing is a shred, a tatter of what he saw. Only the moon remains as it was then, and the inner urgency of wild things.

Uncontrollable laughter and crying has always felt the same to me, the chest convulsions, the in and out of body location of them both as if something like a cloud descended, not on you, but into you, the feeling for the period after it has overtaken you that you might not be the composer of your own life, or even the musician, but just the plucked, strummed or blown instrument. I’m picked up, shaken, put down. The experience is involuntary. Those same hands have just reached into a swift’s nest where a swiftlet is involuntarily doing press-ups with its newly fledged wings. The hand has lifted it quickly, pulled the little ball of almost weightless flesh and feathers out into the twilight and thrown it hard into the sky. Already it is screaming and merging its voice with the flock. Already it is flicking and twist-diving over the church tower, hurtling out and rounding the Scots pine and over the old forge roof, then up and over the oaks and the rooks’ nests. Within a few seconds it has completed its first circuit of the village and is out over the sheep fields, over the main road, the mill stream and pond. Then back again and round again, and again. It has no idea where it’s going and is not looking for anything to follow. It’s not fearful or excited, though its mouth is gaping. Like all of us it will always be hungry. It climbs a chimney of air then rolls and plummets back as the rectangles of the houses, the dark clouds of the trees, the little pebbles of the gravestones grow and grow. Its huge eyes take in the face of a human creature staring up at it, and then the creature is gone behind the walls and fences, the hedges, the ancient castle mound.  For the past weeks it has been gaping into the dark of the nest, now it is seeing the dying fire of daylight for the first of many times as the sky swings and revolves. Perhaps time existed for the bird while it grew into its form, while it fed continuously, the days and nights long with waiting. But now time has stopped and there is only air and speed, the changing light, the broken chequerboard of the landscape which will soon change as it heads south, turning dark blue as it crosses the sea, and brown, red and gold over the mountains and desert. It will see streams, rivers, hills and dunes undulating in a fierce light, deep shadows, lands that have not been cut into pieces but flow as a whole. Each night as it heads south it will see the sky more clearly, speckled with light, spattered with light, running with a river of light. Eventually it will find the rains and follow them for months or even years, until the urge comes to head north again. For now it is taking in the cool currents of the sky, the half moon, the taste of flying insects. It will spend the next day or two configuring its senses, feeling the path of the sun, the draw of warmth and the push of cold.

In the churchyard the yew trees have turned black. A first bat is buffeting and rebounding around the church, its little leather wings audible in the almost silence. The swifts are climbing now, in spirals as wide as the village, shrinking to tiny slits in the deep sky. One, two, three, four cross the face of the moon and now I can’t see them.

I don’t know why I feel so sad. I don’t know why I’m laughing.