Tuesday, 31 July 2018

Visitors

A flock of Curlew Sandpipers with a Dunlin (David Lindo)

Stealthily under cover of darkness they move. And finding them in the first light of day helps me break the stasis of summer.  The season seems sluggish by the end of July. The afternoon spike of heat pushes all life to siesta. All appears still, even the sky is empty. The nights are relatively silent, compared to the amphibian and strident mole cricket choruses of late winter and spring, a gentle soporific hum of crickets broken only by the monotonous poot of Scops Owls. And yet across the skies at night, birds are moving.

Remarkably, shorebirds that were in the Siberian arctic perhaps just a couple of weeks ago are opting to cross the interior of the Iberian peninsular, rather than follow coastlines down to their African destinations. We came across yesterday a group of 13 Curlew Sandpipers,  all still showing their russet summer dress. They were feeding alongside some Little Stints and Dunlin. All were adults that had already finished nesting, or had failed to do so successfully, and were pausing en route to their wintering grounds. Just twelve weeks ago I was watching three Curlew Sandpipers feeding on a pool beside the rice fields in the centre of Extremadura, also along with Dunlin and Little Stint, taking a short break in their journey northwards. Now it was happening all over again, the birds now heading south. The modern landscape of the wet rice fields and their associated reservoirs have provided a significant resource for these waders. Have the numbers of shorebirds crossing Spain in the full blast of summer increased since their discovery of these feeding places, or did their ancestors simply make use of the existing water's edges, crowding along river banks and river islands?

Migration is happening year round in Extremadura. There is not a single month when birds are not on the move. The return passage of high-latitude waders starts in June with the arrival of Green Sandpipers fresh from boreal forests and marshes.  In July, the departure of White Storks and Black Kites is already underway. These latter two species will be migrating during the day, but waders and many of the smaller birds like warblers will be flying at night. Some of this migration across Iberia is quite astonishing. There is evidence that marine ducks like Common Scoter wintering in the Atlantic off the North African coast could be making nocturnal non-stop flights across the peninsular, reaching the Bay of Biscay the following day (see the post by Magnus Robb in May 2017 in soundapproach.co.uk). Unlike the waders seeking stopover sites for feeding, some of these migrants would only be detected if they had been forced to abort their flight at some point during the night. This might account for the my discovery a few years ago of a Common Scoter at the Sierra Brava reservoir in early summer.  Unless as Magnus describes, one is tuned-in to their flight calls. On one night in early May I heard a flock of Ringed Plovers flying high over our house.

A group of juvenile Audouin's Gulls in the mist (Martin Kelsey)

Another phenomenon is now being recognised as regular in the depths of summer in Extremadura. This is the appearance of juvenile Audouin's Gulls on reservoirs in our region. This is a coastal species of the western Mediterranean. After the breeding season there appears to be a dispersal of juvenile birds with several records, mainly in July, every year in Extremadura. I first witnessed this movement in 2015 when I found one and then subsequently a second bird at my local patch at Alcollarín Reservoir. This year, there had been a couple of reports of birds in southern Extremadura and my birding mate, David Lindo, found three at a site near Mérida. At my first opportunity to go, I went down to Alcollarín. It was dawn and despite the sky being clear at home, I arrived at the reservoir to find thick fog. I made my habitual stop to start the scan the water, but visibility was extremely poor. As I was wondering what to do, I caught sight of four juvenile gulls disppearing into the mist. All I could see of them was their rather long-winged and elegant shape, overall dark plumage and a distinctive white "V" on the base of the tail. I was almost certain that they were indeed Audouin's Gulls but frustratingly they seemed to have gone. I spent the next hour checking places along the bank where gulls often rest, but every stop drew a blank. I had just five minutes left before having to head back home, so I returned towards the place where I had started. On my way there, out on the water, I could see a group of dark gulls swimming. There were 13 of them. Despite the mist which gradually started to close in, I managed prolonged enough views of them to confirm my original  suspicion.  When one flapped its wing to show the diagnostic white panel in the centre of the underwing, therewas no doubt at all. At that moment a Black Kite flew low over them and they all took off. Gracefully the flock of Audouin's Gulls circled around in front of me before veering off towards the centre of the water body, disappearing again in the fog.

Juvenile Audouin's Gulls in flight (Martin Kelsey)

The following morning I was back, this time under perfect conditions. I spent two hours counting duck and grebes (including an amazing 570 Little Grebe), but of the Audouin's Gulls there was not a sign. I could only wonder where that enigmatic and evocative group of 13 had gone to.

Friday, 13 July 2018

Two mornings with dragons

Green Hooktail (Martin Kelsey)

I almost gave up before I arrived. Despite the promised sunny weather (from two independent meteorological sources no less), the day dawned heavily overcast and windy. I had given myself two mornings to visit two riverine sites to explore for dragonflies. The expected temperatures were going to be ideal: warm enough for insect activity but not too hot to be a constraint on my activities. Last year with the prolonged heatwave we suffered, I visited the Guadiana River in search for dragonflies and had to adjourn to the car every ten minutes to drink cold water, so fierce was the mid 40sºC temperatures.  However, the low cloud was not encouraging and halfway on my journey I was poised to turn back, but something kept me going. Providence or serendipity - either way, I arrived at my first stop with the clouds breaking and sunshine bringing life and reflections to the riverside.
Ibor River (Martin Kelsey)

I was at the Ibor River, a tributary of the Tagus in eastern Extremadura, fed by streams from the gloriously folded Ibores mountains. The banks were lined by alders, offering patches of shade over deep pools. As I stood, a Kingfisher plopped into the water just a few metres away. It emerged with a gleam of silver in its bill and flew close past me. I was sure that it had not seen me at all. There were shallows as well, with rounded stones, some with bird droppings, probably from the Grey Wagtail that bounced upstream. Downstream, there was a small barrier across the flow which had created a deeper pool. Here the bank had a cemented surface and there were sun-shades: one of the numerous natural swimming pools that offer locals and visitors alike a refreshing respite from Extremaduran summers. I had deliberately arrived before the bathers. I was less concerned about any disturbance they may cause the dragonflies, but more from a sense of decorum: I would be stealthily working the river bank with my binoculars and camera......
Large Pincertail (Martin Kelsey)

I was delighted to discover that the dragonflies were busy as I approached the water's edge. Two species of Pincertails (Large and Small) made sorties out over the open water of the pool, often climaxing in a chase, before returning to favoured water-smoothed stones. Three species of Demoiselles with their stunning metallic-hued bodies and pigmented semaphore wings, perched on vertical stems of emergent vegetation in between their graceful flights low over the water. As I made my way through thicker vegetation I disturbed Western Willow Spreadwings, which almost as quickly returned to their resting spots.
Small Pincertail (Martin Kelsey)

A movement caught my eye and I was fortunate to get sufficient enough of a view to see where the insect had landed. Deep in shade, it hung vertically: the enigmatic Western Spectre, a species that will be usually well hidden during the day, foraging mainly in the evening.
Western Spectre (Martin Kelsey)

Returning to the riverside, I stood to watch the Demoiselles. I noticed a Black-tailed Skimmer being chased by a smaller, rather pugnacious dragonfly. It even swerved to chase off a Blue Emperor as well. Unlike the Pincertails, it was constantly on the move, patrolling incessantly a ten-metre strip of the bank where I stood, backwards and forwards. It was usually about 30 cms above the water surface and within a metre from the bank. Occasionally it would veer off in pursuit, chasing other dragonflies across the width of the river, or high above me over the bank. I was intrigued both by this distinctive behaviour, but also by its identity. It was not a species I had seen before, but its persistent activity meant that it was not going to perch, so getting a decent image was out of the question. So I put my camera aside and watched.  What was striking were its vivid emerald-green eyes and metallic thorax. The abdomen was rather dark, but when it flew close to me, I would see a row of orange markings along its length. These features literally named the species for me: an Orange-spotted Emerald.

Bathers were gathering and I felt it prudent to make a discreet exit, with thoughts already in my head for a return to this site to try to photograph this beauty, a species known in Extremadura only from the extreme north-west of the region and in this zone of the Ibores.
River Tiétar (Martin Kelsey)

The following morning I explored a very different riverine habitat. North of Monfragüe National Park, the River Tiétar crosses a wide flood plain of intensive agriculture dominated by tobacco and peppers. The banks are dressed by willows and the river by mid-summer has shallows with vast islands of sands and gravels, breeding grounds for Little Ringed Plovers and foraging habitat for Black Storks. I did not see a single person during my two-hour stay. Crossing onto a river island, I trudged across the beach, my sandals filling with coarse grains of sand. There were a few hoof prints from cattle and several otter spraints, but dragonflies were in abundance. The commonest was the Violet Dropwing, along with Broad Scarlets. A Lesser Emperor was ovipositing in a calm channel running between two sand banks. She scouted the edge of the water, pausing to plunge almost half the entire length of her abdomen into the water and then moved to repeat the whole process at another spot nearby.
Lesser Emperor (Martin Kelsey)

I looked again out onto the broad expanse of the river just upstream from a bank of gravel that had been bulldozed two-thirds of the way across. Two dragonflies were chasing each other in rapid diagonals over the water surface. They were rather green with rather orange-tipped swollen abdomen. I felt of a surge of excitement. These were different, but like the previous day's Emerald, showed no sign of wanting to perch.

I trudged onward across the sand, my feet now pressed by the grit embedded inside the sandals. A sparse patch of vegetation, like a minature oasis, lay in my path. I caught sight of movement and tracking it found where the dragonfly had landed - a small bleached twig. It was the same as I had seen speeding over the water: a fine male Green Hooktail, only the second time I had ever seen one (see photo at top of this entry). This has a very restricted distribution: pockets in the Iberian Peninsula, Corsica, Sardinia, southern Italy, Sicily and a few areas of north-west Africa. It had been my target species of the day.

Over these two consecutive mornings, I had spent a total of four hours at three sites (I paid a quick visit the first morning to a nearby stream which has long been a favourite spot of mine). I had seen no fewer than 27 species of dragonfly and damselfly, without too much effort (I had covered barely two kilometres in total). But most of that time was not spent walking, it was spent standing (or sitting) watching and absorbing the differences in behaviour between the species present. In fact, I had been using those characteristics almost as much as physical appearance as a means of identification, at least to be able to spot species that were different. I returned home with a sense of both achievement and excitement, longing again to sitting at this interface of land and water, of knowledge and discovery.