Saturday, 25 June 2016

Of a swift and nightjar

White-rumped Swift (Mark Johnson)
Undetected by our terrestial senses, there was evidently a vast resource of tiny prey items, an "aerial plankton"all around us on the crest of the ridge, as witness the surging groups of House Martins, rising to explore the eddies and whirlpools in the updrafts of air, where millions of tiny invertebrates were being trapped. With the hirundines, were the scythe-winged Common Swifts, pushing barracuda-like in a more predatorial mode, easing parallel to the contour, with a determination that contrasted with the House Martins' cheerful randomness.

From our vantage point we looked down and across a vast savannah of dehesa: the dense stippling of holm oaks over the undulating golden-blond pastures of mid-summer, a managed woodland that has become a landscape, typifying, indeed defining, Extremadura.  Solar-powered vultures used nothing more than the thermals of hot-rising air to lift them hundreds of metres into the air, giving them an advantage against gravity which would enable them to drift effortlessly across kilometres of this terrain.

Our gaze returned to the insect-hunters and a pair of swifts were distinctly smaller than the passing Common Swifts, they also behaved differently, making repeated circles close to us, alternating glides with rapid wingbeats and swoops when they held their wings in a stiff and very narrow "V". As they turned a narrow white band across the rump was easily visible and from below they showed rather bold whitish throats. They were, indeed, White-rumped Swifts, a species abundant across Africa and first recorded in Spain in Cadíz in the early 1960s. Although there were records in Extremadura from 1979, breeding was not proven until 1989. Extremadura now holds perhaps a third of the Spanish population of the species with an estimate of between 75-150 pairs. But I am convinced there are are many more: I have personally seen pairs in at least nine different localities - and all are simply incidental encounters, I cannot claim to have made any deliberate effort to search this bird out.  Mark and Sally stood beside me as we watched these birds make successive passes, making us suspect that nearby was their nest, a disused Red-rumped Swallow nest, perhaps on a rocky overhang below us. We moved on lest our presence was disturbing them, but I doubt it was: all swifts seem to make a routine of  successive passes before entering a nest site, which must be more than simply the result of misjudging approach speed and angle.

Swifts are a simply captivating family of birds, the most aerial of all and of the four species breeding in Extremadura, three showing a particularly strong association with human infrastructure. Many of the Alpine Swift colonies here on are bridges or the dams of reservoirs, whilst it is impossible to imagine our local town of Trujillo without its gangland of screaming hordes of Common and Pallid Swifts in their manic charges along the narrow streets and between the rooftops. They share with nightjars the anatomical curiosity of tiny bills but huge gapes. These must function superbly as the birds hoover-up tiny airbourne invertebrates. It is estimated that the bolus of food delivered to the nest by a parent swift may contain up to a thousand creatures.

In the centre of Trujillo I had occasion a few years ago of watching how a nightjar uses its giant gape to catch food. I had been invited to a wine-tasting event and Claudia generously offered to drive into Trujillo later that night to collect me. As she drove into the Plaza Mayor, somewhat past one o'clock in the morning, she saw a rather dubious-looking character standing alone in the square pointing to the heavens. Her apprehensiveness can only have increased when she realised it was me. I was standing entranced by the sight of a Red-necked Nightjar perched on the metal cross on the top of St.Martin's Church and making sallies every couple of minutes to catch moths attracted to the lighting around the square. It was the first time I had ever watched a nightjar foraging and it capped what had been a most convivial evening.
Red-necked Nightjar (John Hawkins)
"Nightjarring" is for many a special birding experience, given the the combination of such cryptic birds, their curious calls and their emergence at dusk. It is about standing on a track at evening and waiting for the mechanical-sound of their songs (in the case of the two species in Europe) to vibrate from the woodland edge, coupled with hope of a sighting of the narrow-winged, long-tailed bird gliding across a gap of open sky. It forms the stuff of life-time memories, and I always have a tingling sensation on my neck and a thump of adrenalin in the pit of my stomach when realising that what I am experiencing will stay as a memory for ever. Such was my feeling on the evening before the solstice this June, as I stood at a place recommended me by Dave and Sammy Langlois, not far from their home in La Vera, a special part of Extremadura on the southern flank of the Gredos Mountains. It was the third year running that I had arrived mid-evening and mid-summer to try my luck in listening to (and hopefully seeing) European Nighjars, a species which is far less common here than the large Red-necked Nightjar. My previous attempts had been failures: nightjars are fickle creatures and we can only guess at the factors which determine whether the bird will choose to call or not. But my expectations were high: it was mid-June, a warm, calm evening with the waxing moon rising, just a day shy of full moon. I parked the car beside some pines, in habitat which was perfect for the species: belts of pine trees, bracken-filled clearings and scrubby hill sides. To the north-east I was confronted with the magnificent sheer mountain massif of the highest part of the Gredos, with ravines close to the peaks still filled with snow. I strolled along the path but stopped in my tracks as soon as I started to hear the nightjar's churring. It was coming from the direction of the very stand of pines where I had parked. I quickly returned to the spot and caught a glimpse of a silhouette of the bird as it left a song perch in a pine, clapping its wings and growling before gliding down into the scrub. I waited for a couple of minutes, wondering whether that would be my only glimpse of the bird, until it rose again and this time approached me. Amazingly it settled on a branch of a tree just in front of me, barely a few metres away.  I slowly lifted my binoculars to my eyes.

What I could see was almost transcendental as an experience. My field of view comprised the almost full moon on the left of the image, with the evening early enough for its brightness not to create a dazzling glare. In the centre, perched longitudinally on a branch and sideways-on for me was the European Nightjar, with enough light for me to see features of its remarkable camouflaged plumage. It was facing left, making an impression of its head, tiny bill and long rictal bristles trimmed by moonlight. And as I stood and watched it started to sing, an extraordinary pulsating churring, which it produced with its bill barely open. At that moment I felt an utter and complete connection to this entire juxtaposition: the moon, the clear sky, the branch and the bird. It was a sense of privilege bestowed and then only broken when the bird took off again, clapping its wings and then gliding into the obscurity of the darkening hillside. I could not possibly have asked for anything more.








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