Swifts in Collserola

Written by Lucy Brzoska

The city doesn’t get more pristine than this. It’s the middle of July, typically a month of stagnant heat, when the sky is discoloured by smog. But in today’s diaphanous atmosphere, Barcelona is visible in intricate detail and the sea is like deep blue silk. After yesterday’s torrential storm, there’s a mountain freshness in the air that promises a good night’s sleep. The soaring swifts take your heart that little bit higher.

I’m in the southern part of Collserola, after catching the funicular to Vallvidrera, where rich Barcelona citizens used to retire for the summer, in the days when people didn’t travel far for their holidays. Once you leave the houses behind, you can follow the ridge to Sant Pere Màrtir, the last hill before the Sierra de Collserola drops down to the Llobregat river plain. There used to be an ermita here, before they tore it down in the 1930s and put up a red and white radio transmitter. Only the name remains, and the stunning views, as the hill falls abruptly away to the city.

I turn inland, where the slopes are more gradual and there’s a labyrinth of paths among pines, small holm oaks and broom. There’s a restlessness about the landscape. A considerable part of Barcelona’s swift population are also spending their Sunday evening on Collserola and the hillsides are swarming with them.

Mainly Common swifts (Apus apus), but the majestic Alpine swifts (Apus melba) stand out with their gleaming white breasts. Their wingspan approaches that of the approaching kestrel, who suddenly accelerates and takes a swoop at one of the house martins mingling in the crowd, making it yelp in alarm.

The path takes me to one of the deepest recesses, where Fragrant clematis (Clematis flammella) has run amok, smothering other plants and bushes with white flowers. The swifts are here too, swishing past, cutting the air to ribbons.

I start climbing up among oak trees, and the swifts cast their shadows on the path. There must be hordes of insects after yesterday’s rain, and they’re intent on hoovering the lot up. The only sound is the slash of their narrow, flexible wings, interrupted by the cheerful gossip of some passing swallows.

Up the grassy slopes, nearly back to the top of the ridge, the density of swifts is even greater. They pass very close, turning incredibly tight circles at relentless speed, weaving intricate flight paths. My camera can only capture them as flickering symbols.

Most of the city is now in shadow, as the sun sets. Only the part nearest the coast still glows. To the north, powerful storm clouds have risen, reflected in the sea.

When the sun has gone down, the swifts ease up, and begin to drift back towards the city. Perhaps some will be going back to their nest holes, even though the breeding season is virtually over. The Alpines are here till October but the Common swifts only stay for three months a year. Each one is linked to a particular barrio, street, unobtrusive hole.

The orange horizon behind them, the swifts float out into the dusk. It’s a vertiginous thought that they’ll be on the wing non-stop till next spring. And those who survive their first migration have 2 or 3 years of flight ahead.

Excellent website about swifts:

http://www.commonswift.org/common_swift.html