Not-So-Common Swifts

If any bird typifies Edinburgh in summer it is – or at least was – the swift. There are no house martins or swallows in the centre of the city; swifts are the only insect hunters we see overhead. The beginning of summer is marked by their arrival in May. We enjoy them for just three short months before they head off, juveniles first, in mid August. This spring, of 2021, was exceptionally cold and their appearance was delayed beyond the 15th of May, the date when I expect to look up and see one overhead. Their wings are long and stiff with a short ‘arm’ and long ‘hand’. They generate propulsion on the downstroke and the upstroke. Head-on, the wing action has a striking ‘whirling’ appearance as if the wings were rotating. Famously, they eat, sleep and mate in the air.

Swifts have very short legs and tiny feet. Indeed, they were once thought to have no feet at all – hence their scientific name Apus (a-pus, no feet). Apus apus, the common swift, is one of those select species that was so good, they named it twice. Convergent evolution has resulted in superficial similarities between swifts, swallows and martins but swifts are more closely related to hummingbirds. They also look a bit like smaller versions of the nightjars that precede them on the taxonomic list. The huge alpine swift with its white belly and wingspan of close to 2 feet is something else. I have seen and filmed one in Scotland, an experience I will never forget.

Swifts live up to their name. They are the fastest of birds in level flight, reaching 70mph. Peregrines can achieve greater speeds but only in a power dive. Swifts winter in Africa and are masters at using the winds associated with weather fronts to aid their movement. They won’t hunt in rain while they are in Europe and will fly hundreds of miles around bad weather to find food. They pack the insects into pellets in their throats to transport back to the nest. Swifts nesting in the west of Scotland have been tracked flying to Loch Neagh in Northern Ireland to feed. If the weather is bad and no food is available, the young birds in the nest will go into a state of torpor for up to 48 hours. Hummingbirds can perform the same trick.

When I moved to an upper flat in the New Town in 1979 I became much more aware of these birds. The top floor rooms had coom* ceilings with large single-pane skylights set into the pitched roof. I could watch swifts traversing that patch of sky from my bed – or my bath. Later in the season, ‘screaming parties’ of speeding swifts would hurtle through the airspace above the gardens at the rear of the tenement. I watched them from the common stair windows.

Gangs of screamers would pass low overhead at a beer garden we favoured in Morningside. I found the strange noise atmospheric and never unpleasant. Even then, 40 years ago, the numbers were no match for the fathoms of swifts and hirundines you see over urban areas in France and Italy but now they are even less common. This year I have only witnessed one small party over a friend’s garden, but they were a welcome sight. The most reliable place to see them locally seems to be over the tenements of Marchmont where presumably there are suitable sites for nests. Once airborne, juvenile swifts can stay aloft continuously for 10 months or more without ever touching down.

Historically, swifts nested on cliffs, in caves and in holes in trees. A small colony in the Cairngorms still does this. Deforestation meant a move to the towns where they used spaces under slates and eaves to nest. Swifts mate for life and re-use the same nest site. The nest is made from feathers and other detritus collected on the wing. Sometimes the nest material is eaten by clothes and carpet moths during the 40 weeks it is abandonned by the birds. Even more unpleasant are the huge blood-sucking ticks that have evolved to parasitise the birds. The equivalent size in a human being would be a shore crab crawling about in our underwear.

The reason the numbers in Edinburgh are so seriously diminished is uncertain. The lack of insects is a possibility, as witnessed by the current dearth of fly squat on the front of our cars. Increased affluence has perhaps resulted in Edinburgh repairing the more crumbly bits of its ancient built environment, reducing possible nest sites.

My office at the Western General Hospital and the coffee room next door looked onto a large enclosed area surrounded by the original 1865 Victorian sandstone hospital building, including a clock tower. The clock was correct twice a day. As usual in the NHS, the enclosure had been crammed with later, cheap, flat-roofed buildings including the dining room and kitchens. A pair of swifts nested in a hole in the wall below the clock tower opposite our offices. Probably the site of some old pipework, the hole was small and situated about 10 feet above the flat roofs. The birds would fly straight into this tiny aperture at top speed and I enjoyed watching them come and go.

Swifts prefer to launch themselves by dropping from a perch using gravity to increase airspeed. The lore is that swifts, with their tiny legs, cannot take off from a flat surface. Once, while eating lunch, I saw a swift exit the hole then plunge downwards crashing onto the flat roof. I was already preparing a rescue mission in my mind. ‘Watch!’ I said confidently to my colleagues, ‘It won’t be able to take off’. As I said this, the fallen bird whirred its wings and rose into the air with little apparent effort. Most texts now specifically say that they can take off from the ground. One winter morning I came to work and glanced out of the window to see that the hole had been cemented up. Not all maintenance is an improvement.

Now, in early August, the michaelmas daisies, buddleia and Japanese anemones are in flower. Soon the swifts will slip away and the children will return to school. The days are already noticeably shorter and today it felt a bit chilly out of the sun.

*a sloping ceiling under a pitched roof.