Saturday, 31 August 2019

A bequest from the drought

Emerging for the first time in 50 years from the drought-stricken Valdecañas Reservoir, the five thousand year old Dolmen of Guadalperal (Martin Kelsey)

We are facing the third worst drought of this century and it could become much worse if the autumn rains on which we depend to break the drought fail. Whilst many of the small rivers here are habitually dry by late summer, the impact is telling on the farm pools which provide water for livestock. Even those which are reliably holding water in August have water levels which are far below normal. Perhaps the most dramatic images are the reservoirs. The Valdecañas reservoir is the fourth largest in Extremadura in terms of water capacity and was created in 1963 with the completion of the dam across the Tagus River, the longest river in the Iberian Peninsula. But because of the drought the reservoir holds just over a quarter of its potential and the water body, although still vast, appears shrunken and bordered by vast margins of bleached pebbles and sand, the surface shimmering in the late summer heat.

We were there on an impromtu family trip to see for ourselves a remarkable bequest from this drought. For the first still since the reservoir filled over 50 years ago, the water level is now so low that a megalithic site, a dolmen hidden from view for so long is now visible. Built about 5000 years ago on the banks of the Tagus, comprising 140 granite stones, the site was known by the Romans but was only subsequently rediscovered by a German priest and amateur archeologist, Hugo Obermaier in the 1920s. Transportable finds were sent to Munich, but the stones were left and within 40 years were submerged under the rising waters of the new Valdecañas Reservoir.

Although the monument's reappearance had reached the newspapers, there was not much we could easily find regarding specific advice on how to visit the site itself. So we set off this morning as early as possible to avoid the heat of the day, forecast to reach the high 30s. The most direct route to the site was impossible because our way was barred by a padlocked gate and entrance to the large private estate of Guadalperal, on which the dolmen was located. Reservoirs are state-owned and their immediate banks are public-rights of way, but we could not cross this private land to reach the shoreline. Eventually, we found a road which led to a pumping station where we could leave the car and walk.

The trek took us across varied terrain: flat sandy bays, damp green zones and treacherous gravel banks. We had spent too much time finding this access point and the sun was already high in the utterly cloudless sky. Migrant Common Sandpipers and statuesque Grey Herons were the only signs of life beside the water on the right of us, apart from the slap of breaching carp on the surface. To our left the land rose and disappeared into the cover of the holm oak dehesa. It took us a full two hours hike to reach the site itself, we had passed four couples of people returning, whilst a similar number were spread ahead of us and behind.
The standing stones surrounded by a an embankment (Martin Kelsey)

The site is marked by a ring of stones lying flat on the ground and a bank of gravel (which would have been turf-covered before submergence), with an entry passage from the east. The bank is so high that as I approached I would not have imagined what lay behind it. Indeed it was only because there were a handful of people standing there looking down that I suspected (and hoped) that we had arrived. Once on the bank we could admire the standing stones below us, set in concentric rings. Some have described this Dolmen of Guadalperal as the Stonehenge of Spain.

The site has been under water for over fifty yeras (Martin Kelsey)

As I stood there I tried to imagine the landscape five thousand years ago. The brooding Gredos Mountains to the north would have looked pretty much the same. The Tagus River would have meandered across this plain before reaching a rocky gorge where the dam now stands. Perhaps there would have been marshes beside the river, whilst the wood pasture now on the rising ground would have been denser Mediterranean forest, still dominated by holm oaks. Perhaps there would have been small clearings and areas for grazing on these gentle slopes, with the livestock moving down to the river to drink.

A boatman appeared, bringing some visitors across from a village on the other side of the reservoir. We agreed a fare for him to take us back to the start of our trek and the breeze as we sped back across the water was a welcome respite against the heat of the midday sun. We clambered back through the woodland and I was distracted by the call of a Pied Flycatcher. These autumnal migrants would also have been passing through these same woods in late August five thousand years ago.

Tuesday, 6 August 2019

Countdown to a late summer dawn

Little Bustards at dawn (Martin Kelsey)

I arrive at 07.00. The eastern horizon, which gave an eggshell blue hue as I left home twenty minutes earlier, now glows apricot. This smoothly fades into the blue-black inky wash of the rest of the sky. Within seconds I hear the first bird calls, the wheeldee-eee of Crested Larks, closely followed by abrupt tics from Corn Buntings. Both are unseen, the pre-dawn gloam just sufficient to mark the open horizon here on the plains, and the proud outline of the Gredos Mountains to the north, but there is no contrast to pick out movement over the dusky barren grasslands. That is until a party of twelve Calandra Larks rise above the skyline, twanging in their bounding motion across my view. The combination of gradually improving light and my eyes tuning-in helps me to pick up the direct flight of a Corn Bunting, barely two metres above the the ground, no-nonsense and purposeful. A stocky outline on top of the chimney on an outbuilding identifies itself as a Little Owl. Its mate sits on top of a nearby fence post, a stoic blob. There are more contributions to the soundscape: a chatter of Magpies, distant Collared Doves, an Iberian Grey Shrike, along with a rooster and distant cowbells.

Apricot sky on the plains at dawn (Martin Kelsey)

At 07.13 scattered clouds to the north-west are becoming roseate-tinged. Small parties of Corn Buntings continue to pass, urgently like commuters. Half-way up a windbreak tree sits the broad-shouldered shape of a Spanish Imperial Eagle. It looks almost wholly black in this light, even with a telescope the emulsion white on "elbow" of the folded wing barely discernible. Beef cattle ponderously move across the field (what can they find to eat where even the parched sparse grass stems have crumbled?), with Spotless Starlings sauntering at their hoofs. At the top of a distant rise are farm buildings from which are delivered the yelled commands of a shepherd and his dogs bark in response. From a similar distance issue the ringing pprrrt calls of invisible Bee-eaters.

At 07.26 it is "sunrise", but the topography of the land  means I have yet to witness its appearance.  It is now the coolest time of the day and feels distinctly fresh at 19ºC (compared with the 36ºC twelve hours earlier). Whilst I have been here, four vehicles and a large truck have passed me on this rough dirt track, wheels crunching on the gravel and billowing dust. Here the farmers live in the town and drive to their work each day, greeting their dogs that have guarded the corralled sheep during the night. At my feet, there is another track, and it too has become used by agricultural workers. Harvester ants are setting out from their burrow, meeting some early risers negotiating their passage back with awned grass seeds.
Harvester Ants (Martin Kelsey)

The growling purr of Black-bellied Sandgrouse distracts me from my ponderings on the ants and I watch three flying low over the field, in fast direct flight, swerving as if on a hand-brake turn and swinging in to land. There their aerial dynamism is transformed to a trundling, shuffling gait.

At 07.30, the sound of the Bee-eaters is becoming incessant and far across the field a flock of over fifty birds emerges, spreading across the sky in long shallow glides. Three minutes later, the sun finally breaks the horizon. At that moment, I hear too the more strident calls of Pin-tailed Sandgrouse and Spanish Imperial Eagle starts barking. I turn but the eagle has already flown. It must have dropped in a long glide into the valley that is hidden from my view.

It is 07.41 and I hear a high-pitched hissing sound above me ssiissiissiissii. It heralds the wonderful sight of a group of Little Bustard, 13 in total, which pass overhead, turn and offer me a second fly past. The males still bear the nuptual black and white chevron on their necks. More Pin-tailed Sandgrouse are calling, as they make their dawn forays for water. Some I find, but others pass over heard but not seen: to locate them in the sky is a challenge with a call that has surely evolved to deceive. A Roller sits on a fence, hunched with its blue plumage brightening perceptively as the light improves.

A male Montagu's Harrier patrols the top end of the field at 08.00. A level flight, two metres above the ground, its slender tail held perfectly horizontally giving the bird a linear appearance, propelled by slow deep wingbeats which pushes it into a long, graceful glide. High above three Cattle Egrets pass over, seeking to join the starlings with the cattle.

At 08.16, three Black-winged Stilts noisily approach a pool that has shrunken so much in the summer drought, that from where I stand I see no water. Only the quacking of Mallard has betrayed its presence. Two sandgrouse fly to the west of me. Although together, they are two difference species and it is satisfying to see clearly the difference between the stocky Black-bellied and the slimmer Pin-tailed.
A Pin-tailed and a Black-bellied Sandgrouse flying together, distantly (Martin Kelsey)

I have stood here now for a hundred minutes and it is time to leave. I have seen about 420 individual birds of 25 species on terrain that has the feel of a dustbowl. All have been local breeding birds, there was no sign of any autumn migrants, although the flocking of the Bee-eaters was a presage of their imminent departure.