Tag Archives: wading birds

Wading birds – an outing to Brazo del Este, Seville

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

Impact of heavy rainfall on wading bird numbers

22nd February 2011

Last week we had a lot of rain, high winds and some very dramatic thunderstorms. I’ve commented in recent posts on the noticeable effect this winter’s heavy rains have had on the water levels of the Guadarranque and Barbate reservoirs and a visit to the estuary and lagoon here in Sotogrande at the weekend confirmed there to be high water levels there too. It was interesting then to come across this article in this week’s  ‘Sur in English’ newspaper on the  effects of  the exceptional rainfall levels on the wintering wading bird populations. Although the article quotes numbers of birds and species counted in the neighbouring province of Malaga, I’m sure similar patterns will have occurred here in Cadíz too.

bird numbers in malaga’s wetlands have doubled this year due to heavy rainfall

Figures show an increase in the number of aquatic birds this winter in Malaga province. But at what cost to other species?
22.02.11 – 12:26 – George Prior |Axarquía
Malaga province’s unusually high level of rainfall this winter has meant the numbers of aquatic birds have soared to figures not seen since 1998, according to the Junta de Andalucía.
Remedios Martel, the Junta’s Head of Environment, reports that water levels at the majority of the province’s 28 wetlands are at a ten-year highs and there are more than 60,000 bird wintering in these areas. The census registers 53 different species which is also the highest in a decade.
The investigation shows that more than 60 per cent, or some 37,000 birds, are at Spain’s largest lake in Fuente de la Piedra, including 6,500 flamingos, a particularly high volume for this time of year.
Bob Wright, founder of the association, Birding Axarquía (birdingaxarquia.blogspot.com), says the weather has been a boon for the area’s aquatic birdlife.
“The wet winter we’ve had has certainly attracted water birds. Recently, for example, there were thousands and thousands of Mediterranean gulls on Lake Viñuela; and everything suggests it will be a good season for the breeding pairs of flamingos over the next few weeks too,” explains Bob.
“We’ve registered at least a dozen White-headed Ducks, which are one of Spain’s native, endangered species; it’s a good sign as at one time there were only 11 pairs left in Andalucía. There has also been a significant number of sightings of coots as well as diving birds such as cormorants, as the water is so deep.”
On the flip side, the bird enthusiast warns the picture is not as rosy for other species.
“The Junta de Andalucía is right in its findings that there are significantly more water birds this winter due to heavy rain and high water levels in the marsh and wetlands; but it needs to be stressed that this has also been to the detriment of other species.
“High levels of water in lakes, streams and rivers have meant there are not as many small waders, such as the Common Sandpiper, as there should be, as they feed off small invertebrates and insects in the mud or exposed soil at the edge of a river or lake. Larger waders like storks and herons, are more numerous in comparison this year,” he confirms.
Temperatures
Not only has the winter been wetter, it has also been averagely two degrees colder than the norm. This too has had a knock-on effect for the province’s birds.
“The cooler temperature have prevented many of the migratory birds coming back to this part of Spain,” says Bob Wright.
“We are only just beginning to register species like House Martins and Swallows, which we’ve starting to see again over the last few days; last weekend we also noticed the first Grey Wagtail. But it’s probably still too cold to see swifts just yet though.
“It’s an exciting, if not crucial, time of year for the native and visiting birds of southern Spain. And the latest figures highlight what a huge impact weather patterns have on our wildlife.”

Are nesting wading birds killing Cork Oak trees?

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

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

White Storks sitting out the rain

White Storks are a characterful and integral part of the local landscape and their residence here is actively encouraged, with many areas providing purpose-made platforms on top of pylons etc. A breeding colony thrives at San Roque de Estacion where nests occupy the tops of just about every available low-rise pylon set along the railway track. The numbers of birds here has increased noticeably over the eight years we have lived here and birds are having to move along the A-405 road towards Jímena de la Frontera to  find fresh nesting sites. Many of the birds remain here during the winter months rather than migrating to N Africa and can be seen around and about hunting in fields and even up on their nests. I love to see them and if I’m heading in that general direction, often make a longish detour to see what they’re up to and the sight is always included in tours for visitors that don’t know the area.

WHITE STORK - Ciconia ciconia

By now, late January, many of the birds have returned to their nests with their mates and occupy them pretty much constantly, guarding against the invasion of potential squatters. I went for a look yesterday and found that many of the nests were indeed occupied, by either one or two birds, although there were a few empty ones too. The birds stay put even in the rain and I took some photographs as they were drying off and preening between some heavy falls.

A damp bird preening its feathers

A White Stork (with leg ring) coming in to land

WHITE STORKCiconia ciconia Spanish : Cicueña Blanca
  • White storks (Ciconia ciconia) have been studied intensively over the years as their habits and survival are closely connected to how we treat or manage our environment. They are one of the key species used to promote public awareness in the fight for nature conservation.
  • White storks travel south to the warmer climates of Northern Africa for the winter and return to various parts of Europe to breed in summer. According to the last census, Poland is by the far the most popular host for White Storks with over 50,000 breeding pairs. Spain follows second as an attractive host with Portugal and France showing an increase in numbers.
  • Between the years 1970 and 1990, there was a sharp decline in the White Stork population and the census count was at its lowest in 1984. There has since been an increase in breeding pairs, particularly in the western part of their nesting regions but their numbers have not reached what it was before the decline. Their status is therefore listed as ‘depleted’.
  • Hazards: Out of the many factors that affect the White Stork’s survival, mankind has the largest impact. Development in areas that were previously natural breeding grounds displaces them. Uses of chemicals in modern agricultural practice depletes or poisons their food. Some suffer electrocution by high voltage power lines, especially those along the White Stork migratory path.
  • Reasons for Re-population: Between 1984 and 1994-05, the population increase along the western migratory path has been attributed to favourable winter climates. A number of White Storks also chose to winter in Southern Spain instead of crossing the Strait into Africa. Changes in their feeding habits also led to a rise in number of breeding storks along the Iberian Peninsula (more irrigated fields and large garbage dumps provided alternative feeding).

The Human Connection

White Storks build their lives close to humans, nesting near populated areas and even on rooftops whereas their counterpart the Black Stork, chooses to remain at a distance and not have human contact. It makes sense that how we live will naturally affect the life of the White Stork thus effectively changing the status of the White Stork from just being another bird to being a lighthouse, warning us of the changes in the environment. In paying attention to their survival, we also help protect the land in which we live.

Sources

Extract from Waterbirds around the world. The Stationery Office, Edinburgh, UK. 960 pp. Boere, G.C., Galbraith, C.A. & Stroud, D.A. (eds). 2006.

Ciconia ciconia, White Stork. http://www.birdlife.org.