Seville is the City of the Swift. After four days in Seville in July, one of the strongest impressions left on me was its Swifts. On a recent visit to Rome I have been struck by the murmurations of Starlings. However, the Starling in Rome are not omnipresent in the same way the Swifts are in Seville. Whenever I stepped out in Seville, I could hear the Swifts scream and watch them slice through the air on their scythe-like wings. In the apartment I was staying, their calls would pierce the double glazed windows and wake me in the morning. From the balcony, I would watch them swirling around in circles in a relatively confined space over the street, their orbits sometimes bringing them within a few feet of me. Then they would suddenly break away into the open sky or speed down an opening into another street. I entered the Real Alcázar one morning with my family; one of Seville’s key tourist attractions. A queue had assembled just before its opening time. I did not mind the wait as from the square outside it I watched flocks of Swifts swirling around.

I almost forgot that I was there to view the Real Alcázar, a royal palace, whose upper levels are still in use by the Spanish Royal family. It is considered one of the finest examples of Mudéjar architecture in the Iberian Peninsula. It also has several gardens contributing to Seville’s reputation as a city with fine gardens. On entering the Real Alcázar I was first distracted by the morning light on the bark of a Sterculia tree. The lowermost parts of the trunks of this tree often have a layer of spiky thorns. This is probably a defence against herbivores which may strip the bark and kill the tree. I could see longitudinal green lines on the surface hinting at edible bark on the surface for herbivores. Most trees often grow a tough and inedible bark. I wonder if the Sterculia’s strategy has been to opt for defensive thorns instead. Behind the Sterculia was a wall painted in the orange-yellow which many a Mediterranean wall is painted with. It made a featureless backdrop which was useful for showing how menacing the thorns look when viewed close up.

A party of tightly bunched Swifts sped past, a few in inches away from the wall. The shadows racing along the wall defined their shapes sharply. In a courtyard other parties of Swifts raced around like greyhounds that had been unleashed on a race. I used a wide angle lens and pre-focused and waited for a group of Swifts to go screaming past. They circled around like goldfish in a bowl. But at high speed and with their screams, they seemed like some demented souls trapped in hell. Then they would break away into the open sky and hurtle away, wild and free, unfettered; spirits of the European summer.

In the evening, we walked past the Seville Cathedral, on Avenue de Constitucion. It sounded like some demented souls who had been confined to hell were screaming for salvation. Swifts, possibly with nests out of view behind statues, were calling loudly from an arch. All along the street other Swifts flew about announcing nightfall.

Swifts are wonderful birds with a remarkable life history. When a Swift leaves its nest it may continue to fly non-stop for a few years without ever landing to rest or coming into contact with anything affixed to the earth, until it has attained adulthood and it is ready to build a nest. Astonishingly, they sleep on the wing, at night flying higher up. The only other animals to keep constantly on the move are the cetaceans or the whales and dolphins. They sleep with one half of the brain shut down whilst the other half keeps them moving and brings them up to take in fresh air to keep breathing.

Seville is also famous for its gardens and parks. We spent a pleasant morning walking in Parque de Maria Luisa (Maria Luisa Park). I took the time to photograph trees such as the Jacaranda which is more typical of a tropical climate but is planted widely in Seville which enjoys a Mediterranean climate. The highlight was a Spotted Flycatcher which was feeding two young. When I saw it, I stayed where I was resisting the temptation to approach closer. It was quite bold and flew up to me landing on the ground as well as on a park bench near me. It was used to people and as I chose to stay where I it continued to have a routine of flying in close to me and picking up insects and flying back to its young.

As the July temperatures cooled in the evening we walked to a nearby bridge over the River Guadalquivir. From the Puente de San Telmo we watched a flock of House Martins flying to and from their mud nests attached under one side of the bridge. From the bridge I could watch them flying below me with their distinctive white rump breaking up into two an otherwise uniformly coloured black upperpart. As they banked or flew above me I could see their white underparts. Flying above them was a flock of Swifts. To my wife and two children, I pointed out the Swifts and Martins as a good example of convergent evolution. Their shapes are very similar having evolved for an aerial life. But despite being so similar in appearance, they are in two different and unrelated families. The Martins are a member of the same family as the Swallows. Although they are also very expert on the wing, the Swallows and Martins land frequently to rest during the day and will always perch at night to sleep.

In Britain, both House Martins and Swifts have disappeared from towns and cities. However, there is more awareness now and efforts are being made to bring them back through measures such as encouraging property developers to use ‘Swift Bricks’ in new developments. These are special bricks with holes in them which provide a ready-made nest cavity. A few days later I was back in London walking along the South Bank of the River Thames near Tower Bridge. I was pleased to see a small flock of House Martins which breed in the area enlivening the river with their aerial sallies.