Summer Flights

They’ve made it again,
Which means the world’s still working, the Creation’s
Still waking refreshed, our summer’s
Still all to come –

                Ted Hughes, “Swifts”

When the swifts reappeared I was relieved. Hughes’ lines (which I’ve quoted before) resonate in my mind, and every May I start to look up, listen for them. There were some in the middle of the month, but then none for at least two weeks. Had their nest sites been destroyed? Had too many died on the flight up from southern Africa? Swift populations have been under pressure for some time. Was this the year our local ones had failed?

But then in early June I saw (and heard) them again. Swifts, swallows, house martins are all markers of summer’s arrival, and it only takes a little attention to tell them apart. I think swallows are my favourites to watch. Their arcs over open field or stretches or water seem impossible. They brush the grass tops, brake and double back, bolt straight upwards and suddenly plunge, brake, snap into a new curve so fast the eye is almost fooled into believing it's seeing six birds, not one.

But swifts are probably the most interesting. They aren’t that closely related to swallows or martins, and have taken the aerial life to an extreme, only ever voluntarily touching “ground” to nest. Apus apus, their Latin name, means “footless”, but they do have feet – minimal appendages.

Their whole appearance says “flight”. Where swallows and martins have reasonably sized bodies, swifts seem almost all wing. As I walk into town in the sweaty suburban heat, the pollen-lined scent of flowers sticky in my throat, I look up, and see black scimitar blades, tiny voids in the summer sky.

They nest along these roads too, so often, especially in the early evening – the air now gradually sprinkled with moisture, the heat absorbed earlier by the tarmac now radiating out from under my feet – they fly at roof height. This is when their black is filmed by gold and their squadrons banks and stoop down towards the houses. The colours are momentary, but every feather refracts a jewelled intensity.

The swifts that nest in the tower of the Oxford Natural History Museum are well documented. A books was written about them in the 1950s, and the museum shows CCTV of the purpose-built nest boxes in the tower on a huge TV screen inside the galleries. The swifts of south Oxford are more elusive. Summer after summer I’ve watched them flying high, flying low, heard them scream overhead. But only twice have I seen one actually land, and duck into its nest.

Swifts’ nests were once cavities in cliffs, perhaps in trees. Now they are almost always in buildings, often older ones, where there are gaps between bricks and roof timbers. South Oxford, with its generally pre-war buildings and frequently (myself included) ramshackle inhabitants, offers many of these niches – so I infer from their close-to-nest behaviour, flying low and screaming.

A group of swifts coming home at dusk is a fascinating sight. Almost in formation they scorch across the arc of vision from roof to roof, their wings barely appearing to move. This apparent stillness in their bodies makes me think sometimes that they have another source of propulsion – are they using a gravitational slingshot like Voyager II passing Jupiter, or do they have jet engines?

It’s the screams that make me think of engines firing. As they come into the area where they nest, they give these high-pitched calls – to their mates, to their chicks, to neighbours. They burst on the ear as they pass over the roofs, first whistle-shrill, then, as the crescents of their wings shoot overhead, deepening slightly because of the Doppler effect. This is where the call becomes more eerie. I imagine it twisting and looping, like a comet’s tail or smoke from a dragon. Then, less than half a second after they appears, they’re gone beyond the houses on the far side. Perhaps they’ll wheel back round, or perhaps the quiet will persist.

That scream, and the staring, bulging eyes, sharp beak and fierce defence of their nests earned them the name “devil birds” in the past. Their disappearance every August and reappearance in late spring was the subject of much speculation, as with swallows and martins. In A Natural History of Selborne the eighteenth-century naturalist Gilbert White wonders if the summer birds somehow spend their winters underground. The idea that they could fly thousands of miles also appears in his book, but both solutions to the mystery appeared equally (im)probable at that time.

Swifts are as much African as British birds. They spend most of the year south of the Sahara – although never touching the ground. They fly high most of the time, feeding, as they do in Britain, on insects that they trap in filament-lined beaks. The journey between takes in seas, deserts and – over some Mediterranean islands – trigger-happy men with guns. A high flock of them can look as delicate as eyelashes against the clouds, but they must be among the most resilient of birds.

This resilience surely puts into perspective the pressure that human-induced change is exerting on the systems swifts rely on. For swifts – which have made a high-risk migration into a successful survival strategy – to be in sharp decline calls into question the reassurance of Hughes’ poem, that “the world’s still working”. (Hughes himself, as an active environmentalist, would have been well aware of the fragility of his assertion.)

The expansion of the Sahara, the increasing unpredictability of the weather and of pesticide use, and therefore the fall in the number of the insects they feed on, and the loss of suitable nesting sites as dilapidated eaves are restored all mean that a bird already committed to extreme endurance is being pushed beyond its limits. A local solution, such as installing nesting boxes, only solves part of the problem. It is as though all the pieces of a swift’s life are being pulled further and further apart, and the species will crash into the gap.

To look at a wild bird up close, to be able to see the feather filaments that ring the eyes, the rippling of the beak’s keratin, is a rare experience. Certainly it always thrills me. But to be so near to a swift is almost impossible, except in the instants it swoops low across a street, wings vibrating and glittering. They flicker in and out of view, the trailing scream fading away only after the sharp bodies have disappeared. This transitoriness, this flickering in and out of the year, is part of their appeal for me – but I also count on their regular appearance as a sure sign of life. As a friend said recently, “The sound of swifts overhead is the sound of summer in Oxford.”