Category Archives: Wetlands of Southern Spain

Wading birds – an outing to Brazo del Este, Seville

Posted on 27/05/2011 | Leave a comment

14th May 2011

This outing was arranged by the Gibraltar Ornithological and Natural History Society. We have visited this site in the plains of Seville in the two years previous to this one, on 14th May 2009 and 15th May 2010, which is interesting for noting consistencies and changes in this very dynamic landscape.

The outing requires an early start from the Gibraltar/Spain border, meeting at 6am, then setting off on a journey that takes around two and a half hours if you drive directly there, or more like three if you stop for a breakfast break, as we do. It is a long drive, but easy going via the scenic dual carriageway from Los Barrios to Jerez de la Frontera, and then continuing towards Seville on the AP5. At this time of the morning there is very little traffic, but the new speed limit of 110 kph added a few minutes to our journey today – of course we kept to it – Jill set cruise control!

Brazo del Este is located 20 km south of Seville in the Guadalquivir river estuary and is an area with one of the highest levels of biodiversity in the Iberian peninsula. This former branch (brazo) of the Guadalquivir is east (este) of the river and has become an extensive wetland, marsh and reedbed area that is surrounded by rice plains and farmland where a variety of crops are grown. It is an outstanding ornithological site, where over 230 species of birds have been recorded. It is noteworthy for its high numbers of waterfowl especially in winter, while in times of drought, birds from the nearby Doñana National Park flock here.

We may have witnessed more dramatic and colourful daybreaks than this morning’s, but as the light slowly brightened we saw a good few raptors, at least one Short-toed Eagle, a Kestrel, Booted Eagles and Black Kites setting off from various night-time roosts, flapping over fields or perching up on pylons and power lines. The number of White Stork’s nests on the tops of shorter pylons along the roadside seems to increase each year, the bird pairs visible in the half-light sitting or standing on their nests, most of which will now house quite well-grown young.

We stopped for breakfast, as always when heading in this direction, at the service area of las Palmeras, located at the turn off for Alcalá de los Gazules. One of the early morning features here is the cacophony of House Sparrows waking up and exchanging noisy but cheerful greetings. Refreshed, we continued our journey, finally reaching the small town of el Palacio at around 8.45am, where Jacaranda trees in full bloom line the main street and numbers of Swifts were already racing around squealing delightedly, and where the temperature had already reached 21°C.

Common Buzzard - Buteo buteo

The road leading from the town to our target site is long, narrow and almost straight, passing through vast acres of flat cultivated landscape that is short on significant features. On its left side there are a few scattered clumps of farm buildings surrounded by large ploughed fields, and a line of telegraph poles is set along its edge. We had our first close bird sighting of the day here; a Common Buzzard that sat enjoying the sun, ignoring us determinedly as we sat in the car looking up at it.

Chicory thrives here

For a good length of it, the land opposite is screened by a windbreak of tall eucalyptus trees fronted by a deep reed-fringed dyke that was brimful of deep water. Windows down, we heard our first birdsong, the unmistakeable loud scratchy tune of a Great Reed Warbler.

A Great Reed Warbler, singing at full throttle

It took very little effort to locate the singer, perched high on top of a bedraggled old reed seedhead. We watched him for a minute, until he flew up into a nearby tree. A Moorhen crossed the road in front of us and a Crested Lark meandered along it further ahead. We stopped again almost next to another Great Reed Warbler, enjoying very close views of him, and spotted Reed Warblers discreetly travelling around low in the reed thicket beneath his perch. Two Black-winged Stilts flew across towards the water and a couple of Black Kites flapped past, high above the fields.

Crop spraying was underway

Inside the site, we had a few moments of concern on seeing that a large area of what was reed-bed last year had been cleared and ploughed. To add to our woes a small crop-spraying plane was buzzing across the fields discharging its cargo. The thoughts that after travelling all this way, not only would there be no birds to see but that we may also be either poisoned or fertilised for our efforts, did cross our minds. But this is a very intensively farmed area, and although a designated Parque Natural, people here have to work hard at making a living; at least there were no tractors racing up and down the track covering us with great clouds of dust as they were last year! (I’m really selling this place aren’t I?)

Our spirits soon lifted when we saw more singing Great Reed Warblers up on reeds, and driving on a short way we discovered large areas of damp and, in places, wet reedbeds. Beyond the tall reeds there were Black-winged Stilts stalking through the shallow water, Purple Gallinules skulking around its reeded edges, Moorhens and the first of several views of a flying Little Bittern. A Cetti’s Warbler threw out its song and three tiny Fan-tailed Warblers were engaged in a tight battle, two of them breaking away and spiralling up and across the road oblivious to us.

Black-winged Stilt- Himantopus himantopus

Jill set up her telescope here and picked up that there were Dunlins in the mix too, one of which had lost a leg but that seemed to be coping well. A raptor flew across and landed on a distant pylon, through the ‘scope we could see it was a Black Kite that had perched up to eat something indeterminate but bloody. The presence of the Black Kite disturbed a large flock of smallish birds that we at first thought were Dunlins, but that turned out to be Ringed Plovers. We went on to discover there were large numbers of them scattered throughout the site, clearly on passage through and feeding before setting off to their more northerly breeding areas.

Purple Heron - Ardea purpurea

Our best views of Purple Herons were of individuals flying between various parts of the site, once they land amongst the reeds they are amazingly well camouflaged and they prefer to stay that way, much less commonly seen feeding openly as their Grey Heron cousins. There were other good sightings of flying waders too, Grey Herons were frequent spots, Night Herons were out and about too. There were a couple more sightings of Little Bittern and most unusually, one of a Common Bittern. Two Glossy Ibis flew across, their profiles unmistakeable against the increasingly bright sun, although not a great light to photograph against.

Glossy Ibis - Plegadis falcinellus

We had a superb view of a Spoonbill flying low over the reeds: last year we had wonderful sightings of a flock then of them wading as a large group with a solitary Sacred Ibis attached.

Spoonbill - Platalea leucorodia

Collared Pratincole – Glareola pratincola

Collared Pratincoles are one of the characteristic and I think most charismatic birds of this area, resembling Plovers (charadrius) on the ground and terns in flight.

Collared Pratincole standing on a mud bank

The habitat of Brazo del Este is perfect for their needs, they favour large flat expanses of land with some shallow pools and marsh, often dried-out flood areas, grazed shore meadows and salt steppe adjoining coastal lagoons and deltas. (They also occur in the la Janda area)

Collared Pratincole in flight; they catch insects on the wing

Moving on a little further we had closer views of Ringed Plover and Dunlin feeding on the muddy shores of a rapidly drying pool, then further back in an area with more water were Spoonbills, Grey Herons, a Purple Heron, White Storks,Little Egrets, Redshanks, Avocets, Black-winged Stilts and Dunlins.

A few of the White Storks & a Little Egret that were part of a larger mixed group

Another moment of alarm occurred when we spotted ‘objects’ floating around on the surface of another pool: at first we thought they may be dead birds, but closer inspection revealed dead fish. We could only speculate as to what had killed them, but nothing was venturing to eat them.

Dead fish

There were not a huge amount of smaller birds flying around, but there were a few Whiskered Terns, Little Tern, Yellow Wagtails and Goldfinches to be seen. There were more Reed Warblers spotted and Great Reed Warblers continued to be heard, but as the heat increased were less frequently seen as they dropped lower down in amongst the reed stems.

Great Reed Warblers continued to be heard but less frequently seen

Much as I love to see birds, I am interested in habitats as a whole and am prone to becoming distracted by ‘other stuff’. The natural vegetation of the site as a whole is of course dominated by stands of Giant Reeds. The roadsides are so dry and sun-baked for most of the year that only the toughest of plants can hope to survive, so the vegetation there consists largely of thistles, plantains etc.

A hedge of thistles along part of the roadside

Aestivating snails clinging to thistle seedheads

Those in flower now attract a surprising number of insects, I saw bees, a few dragonflies, butterflies and a little diurnal moth. The most common butterflies were Clouded Yellows, I also saw mating Small Whites, Green Striped Whites and a pristine Painted Lady.

Clouded Yellow-

Green-striped White - Euchloe belemia

Another pool held an exciting find – a flock of beautiful Grey Plovers, the males in their handsome summer plumage. The sun high in the sky and reflecting off the water, together with the distance away made a decent photograph impossible, so I have included one that I took whilst on another outing on 6th May 2007, at Trebujena.

A pair of Grey Plover in summer plumage

Most of the wading birds we had come across had been on reedbeds on the river side of the track (to our left going in), but we had one of our best collection of species sightings in a pool fairly distant from the track and on its other side. Here there were White Storks, a number of Grey Herons, (at least two of which were very young, probably of this year’s brood), Little Egrets, Grey Plovers, Dunlin, Ringed Plovers and gulls.

A variety of wading birds gathered together

A more expansive view of where the birds were showing the receding water

This was the last of the expanses of reedbed, but we decided to continue along a little further as we knew from last year there were some potentially interesting spots ahead providing a slightly different habitat and attracting some different species of birds. It was a good decision; our first spot was a Kestrel that we watched land on the bare earth of a ploughed field. There was another Kestrel already on the ground and the two of them stayed down, so had clearly found something worth eating.

We arrived at the small bridge that crosses a concrete-lined waterway, where last year we had come across the amazing spectacle of White Storks, Grey & Purple Herons, Little Egrets & a Night Heron all feasting together on fish stranded in shallow water. There were no waders here today, but we did spot Red-rumped Swallows flying around the bridge and stopped to watch as they landed to collect mud from the bottom of the almost-dry dyke, then swooping up and under the bridge, where they are clearly building their characteristic ‘igloo- style’ nest.

Red-rumped Swallow - Hirundo daurica

On the other side of the bridge is a large pool surrounded by a grassy field, where again, last year we had seen two Squacco Herons. No Squacco’s today, but there was a Little Grebe. There were Black-winged Stilts too, actually nesting in the exact same place as they were last year in a surprisingly open spot in the field. Opposite there we had our best Purple Heron sighting of the day as it stood out in the open on the bank of a small river.

We turned back here to head for our favourite venta in the village of el Pinzón, first experiencing a bit of deja-vu as we encountered birds that we had seen in the exact same location in almost the same spots as last year. I am referring to an area of rough pasture that has pylons and cables that last year had Bee-eaters skimming over it; this year we saw only one up on the cables, but it was there. Last year a Short-toed Eagle was perched atop a telegraph pole on this bit of roadside and lo and behold, there it was again today. The final bird in the set was a Corn Bunting perched on the cable and yes, there was a Corn Bunting there today too. It’s reassuring to see that not everything changes in a hurry.

Back on the road and driving away from the site we had our most exciting bird sighting of the day. As we reached the end of the line of eucalyptus trees, a Marsh Harrier shot out from behind them then continued to fly low and fast parallel to the road. Jill adjusted her speed to keep pace with him and to try to keep him in clear view for me to try to photograph through the open driver’s side window. Good job it’s a straight piece of road!

Marsh Harrier keeping pace with the car

At the venta there was another now-familiar sight – a Stork’s nest that is located on top of a tower on the opposite side of the narrow street where the parents were once again feeding growing young.

White Stork feeding young

Are nesting wading birds killing Cork Oak trees?

Posted on 22/02/2011 | Leave a comment

My Dad mentioned an article he had read recently about birds killing off Cork Oak trees and I meant to research it earlier, but forgot about it. I don’t know what triggered the recollection this morning, but whatever it was led me to find this article on what seems to be an interesting website, new to me, that is produced by the Natural Research Environment Council and titled Planet Earth. The link is http://planetearth.nerc.ac.uk and they invite comments on their articles if you think you know better! It’s an interesting article, although it does make it sound as though all the regions’ Cork Oaks are under this threat, rather than those growing in the immediate Doñana area.

Bird conservation leads to tree death

14 December 2010, by Tamera Jones

Conservationists have been so successful at protecting endangered birds in a Spanish nature reserve, that the birds are now killing the reserve’s ancient cork oak forest, say scientists. This may mean some colonies will have to be moved to protect the trees, some of which date back to the seventeenth century.

The trees are the last part of a huge cork oak forest which once covered south-western Spain, and provide food for deer, wild boar and small mammals. The endangered Iberian Lynx often also uses old cork oak trees as breeding dens.

Damaged tree (image: Maria T.Dominguez)

Over the last 40 years scientists had noticed that trees used by wading birds during the nesting season seemed to die more often than trees not used by birds in the Doñana Biological Reserve – a World Heritage site – in south-western Spain. But they couldn’t be sure if firstly the damage could be blamed on birds, and secondly how the birds were damaging the trees. So Dr Luis García from the Instituto de Recursos Naturales y Agrobiología de Sevilla (CSIC), other Spanish scientists and a researcher from the Centre for Ecology & Hydrology decided to find out.

In reserves where bird populations are protected, tree damage can often be blamed on bird populations that have got too big. So Garcia and his team reasoned this could well be happening in the Doñana Biological Reserve.The team analysed the health of 60 ancient cork oak trees, sampled leaves and soil, and worked out how many leaves were covered with poo. They write that, ‘an intense and persistent occupation of trees by colonial wading birds induces large changes in the soil composition and contributes to the decline of the centenarian cork oaks.’

They found that salts in the soil came from the birds’ excrement. Not only does excess salt stunt the trees’ growth, eventually killing them, but the birds break branches, tear off twigs for nests and their droppings are bad for the trees’ leaves. With around 70 nests in any one tree, the researchers found that the nesting birds produce so much poo it upsets the delicate balance of the soil which nurtures the oaks.

The birds’ faeces lead to high concentrations of salts in the soil, to which cork oak trees are particularly sensitive – the salt makes it hard for the trees to absorb enough water. The researchers found that cork oaks which are home to birds like the white stork, the spoonbill and the grey heron are in much worse condition than trees with no nesting birds.

‘If populations of these birds continue to rise, the effect will increase. The source will still be there,’ says Cristina Aponte from the Instituto de Recursos Naturales y Agrobiologia de Sevilla, and co-author of the study published in Biological Conservation. ‘New trees will be used by the colony as the occupied trees die.’

This case of one conservation success leading to the decline of other endangered species isn’t as rare as you might think. Problems crop up when different species have different needs and they live in the same habitat. In Polish forests, cormorants and protected wading birds have harmed ancient trees, elephants destroy endangered plants and trees in parts of South Africa, and the rare chamois in the Pyrenees feeds on the equally endangered larkspur plant.

For managers of the reserve, there is clearly a trade-off between maintaining the area for nesting birds and preserving the ancient cork oak forests. One solution to the problem would be to relocate the colony to a region where the trees aren’t as valuable or rare. But the size of the colonies could make relocation challenging.

As the climate changes, warmer temperatures could bring further problems.

‘Increased water-stress under climate change could exacerbate the problem, because trees won’t be able to get the water they need,’ explains Aponte.

Around 95 per cent of the cork oak forest in south-western Spain was devastated by human exploitation between the seventeenth and twentieth centuries. But remaining trees were kept for producing cork, and to support cattle and game.

Now wading birds nest in the trees from February to July, with colony sizes varying from year to year from 150 to 13,000 pairs.

Luis V. García, Cristina Ramo, Cristina Aponte, Adela Moreno, María T. Domínguez, Lorena Gómez-Aparicio, Ramón Redondo, Teodoro Marañón, Protected wading bird species threaten relict centenarian cork oaks in a Mediterranean Biosphere Reserve: A conservation management conflict, Biological Conservation (2010), published online 3 December 2010, doi:10.1016/j.biocon.2010.11.007

The Egrets have landed

Posted on 01/02/2011 | Leave a comment

30th January 2011

LAGUNA de las CAMELLIAS, SOTOGRANDE PORT

This lagoon, very close to the entrance of Sotogrande Port and backing onto the beach, Sotogrande Playa, is not very big (approx 250x60m), but it is more or less surrounded by reed beds. It is home to a number of resident species of birds that you may or may not see, but one species can be relied upon to provide a regular spectacle: this is the spot chosen by hundreds of Cattle Egrets as their night-time roost.

In the fading light, a White wagtail perched on top of a reed stem in the centre of the lagoon.

I arrived at the lagoon this evening at about 6.15pm as the sun was beginning to go down and tint the sky rose pink. There was not the slightest breath of a breeze, the sea and the surface of the lagoon were almost perfectly flat and the reeds motionless. I heard the calls of Cetti’s Warblers, two of them that seemed to be communicating, saw Chiffchaffs aplenty amongst the reeds,watched White Wagtails dart after flies from perches on reed stems and Crag Martins that skimmed close over the water. But although the light was beginning to fade, there were no Egrets.

A sunlit Cormorant flying to roost

I watched the sky and saw Starlings set off for their roosts, Cormorants in ones and twos passed by hurriedly on their way across to theirs, somewhere upriver and then a single Egret heading my way. It flew in as though to land, but then looped around and flew back in the direction it had come from. Three birds together then did exactly the same thing, then three more. I was baffled by this, wondering if perhaps the water-level, which is very high at the moment, had covered the bank they roost on and forced them to seek alternative accommodation.

Cattle Egret - Bubulcis ibis

Then suddenly they began to arrive in larger groups, flying in quite fast then parachuting down at speed to settle amongst the reeds on the banks of the lagoon like large snowflakes.

A group flying in, legs extended, preparing to drop down to land

The first arrivals were landing in reeds in front of the buildings on the outer edge of the port; although closer to people, this is probably the most sheltered spot. As more arrived, some were slotting amongst those already there while others were spreading further round the bank. In a matter of two minutes the concentration of birds trebled and the noise level increased as the birds jostled for position. I thought back to the birds I had seen earlier and though it possible that they had turned back to wait until a number of birds had settled, seeking the greater safety and security of a large group.

After two or three minutes the covering of birds had begun to thicken - there are about 150 of them in this initial stretch close to the front of buildings and sea wall

After a few minutes of watching I decided to walk a little further around the board-walk to try to find a clearer view and was surprised to discover a second, quite separate roost behind a flooded area of the reed bed that backs directly onto the beach.

A second roost, backing on to the beach

There were a smaller number of birds here, but still about 200-250 individuals.

: By 6.50pm the majority of the birds had arrived, although there were still small groups of new arrivals dropping in from the darkening sky

I stayed until it was almost dark and the birds were beginning to settle, although late arrivals set up protests and a few shifts of position. I’m not the best at counting large numbers of birds, but from rough counts from my photographs I would say there were at least five – six hundred birds in the two roosts, maybe even more. I have witnessed the sight on several occasions and it is always one worth making the effort to watch, even when it is as cold as it was last night.