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ARROCAMPO (ALMÁRAZ)

By Javier Briz (www.digiscopingspain.net)

CHAPTER ONE: ARROCAMPO, THE WHYS AND WHEREFORES

[Capítulo segundo: Los mejores lugares para ver aves >>]

The Reservoir

Less than twenty kilometres to the west-southwest of Navalmoral de la Mata (Cáceres), a town of 17,000 inhabitants, stands the Nuclear Power Station of Almaraz. It is made up by several auxiliary buildings clustered around the central power generation units (2), easily identified by their white domes. It was built in the eighties and looks set to operate for a good few decades yet. The environmental problems bound up with the production of nuclear energy are well known, so we won’t get bogged down in this morass here. Rather will we move on quickly to what is really of most interest to us: the Arrocampo Reservoir.


Built to solve the problem of how to cool down the nuclear power plant’s reactors, this reservoir is a really curious work of engineering. Simple in conception though not in execution, it is really just a huge refrigeration circuit. Water pumped from the River Tagus is made to pass through the generators, thus cooling them down. Naturally the increased water temperature needs to be dissipated as rapidly and as efficiently as possible so it is made to run round a circuit marked off by a heat separation screen until returning to the river (see image 1). This heat separation screen, by the way, is 11 km. long and 8 metres high and serves as a perching point or nesting platform for many birds (browsers please note: it is often used as a perch by the rare great white egret and is the winter roosting place of cormorants).

Water Cooling Circuit

Image – Water Cooling Circuit

 

Particular Features and the Fauna

For those fond of technical details we can point out here that this cooling reservoir has an area of 770 Ha, a storage volume of about 35.5 hm3 and a flooded area of 7.7 km. That said, we can now pass on to the wildlife, which is what is really of interest to us here. The serendipitous effect of the abovementioned natural cooling system is an ecosystem that can certainly be dubbed as special: a zone of shallow water with stable levels and a markedly raised temperature, between 2 and 4 degrees above normal (this will be depend on the number of reactors in operation and the power generated at any given moment, a factor that needs to be carefully controlled by the plant staff, for too sharp a temperature rise, in summer for example, could produce serious environmental problems); furthermore it shows a high level of eutrophication, though this is somewhat offset by the constant oxygenation produced by the pumping activity. An explosive set of circumstances! (“explosive” in the best sense of the word, let’s not jump to conclusions here). This is why the reservoir boasts a considerable biomass at all trophic levels. Bacterioplankton, phytoplankton y zooplankton abound, sustaining successive levels of predators. Worthy of particular note is the presence of Ceriodaphinia cornuta, a water flea (microscopic crustacean) with a tropical distribution range (small wonder). As for macrophytes, pride of place in terms of marshland plantlife goes to the typhales (Typha spp.), which have spread spectacularly in the shallow parts of the reservoir (see photo 1); hence the equally spectacular takeoff of the purple swamp-hen (Porphyrio porphyrio) population over the last ten years! As is always the case, it is this shallow-water plant cover that is responsible for the reservoir’s teeming birdlife.

 Photo 1- The bulrush or reed mace is the mainstay of many bird species. The mist that is produced on many days by the overheating of the water gives the landscape a phantasmagorical look.

Fishlife is varied and abundant (though three-eyed nuclear fish like the Simpsons’ Blinky have yet to be found!), though, unfortunately, there is the usual excess of introduced species. The main species are largemouth bass (Micropterus salmoides), carp (Cyprinus sp.), goldfish (Carassius auritus), pumpkinseed sunfish (Lepomis gibbosus), Iberian barbel (Barbus comiza) but there are more. This abundance of fish explains why it’s fairly easy to see otters gorging themselves in the reservoir: it’s a huge fishfarm)... So at last we come to the birdlife

The Birds

Probably with some inadvertent omissions I give below a list of all the birds that can be seen in Arrocampo. I leave out those with no direct link of any sort with the wetland habitat although I do include those of special interest to birdwatchers that might be found breeding or feeding nearby, such as the spoonbill and black-shouldered kite. Breeding birds are marked in green. I include some "odd" species, either because they are exotics or exceptional in the area (red).

 Photo 2- The striking appearance of the purple swamp-hen (Porphyrio porphyrio and its sheer abundance in Arrocampo make it one of the site’s most emblematic birds. Author’s photo.

 

PODICIPEDIDAE

Zampullín Común Tachybaptus ruficollis Little Grebe

Somormujo Lavanco Podiceps cristatus Great Crested Grebe

PHALACROCORACIDAE

Cormorán Grande Phalacrocorax carbo Great Cormorant

ARDEIDAE

Avetoro Común Botaurus stellaris Great Bittern

Avetorillo Común Ixobrychus minutus Little Bittern

Martinete Común Nycticorax nycticorax Night Heron

Garcilla Cangrejera Ardeola ralloides Squacco Heron

Garcilla Bueyera Bubulcus ibis Cattle Egret

Garceta Común Egretta garzetta Little Egret

Garceta Grande Egretta alba Great White Egret

Garza Real Ardea cinerea Grey Heron

Garza Imperial Ardea purpurega Purple Heron

CICONIIDAE

Cigüeña Blanca Ciconia ciconia White Stork

THRESKIORNITHIDAE

Espátula Común Platalea leucorodia Eurasian Spoonbill

ANATIDAE

Ánsar Común Anser anser Greylag Goose

Ganso del Nilo Alopochen aegyptiacus Egyptian Goose

Tarro Canelo Tadorna ferruginea Ruddy Shelduck

Silbón Europeo Anas penelope Eurasian Wigeon

Ánade Friso Anas strepera Gadwall

Cerceta Común Anas crecca Common Teal

Ánade Azulón Anas platyrhynchos Mallard

Cuchara Común Anas clypeata Northern Shoveler

Porrón Europeo Aythya ferina Common Pochard

Porrón Moñudo Aythya fuligula Tufted Duck

ACCIPITRIDAE

Elanio Común Elanus caeruleus Black-shouldered Kite

Milano Negro Milvus migrans Black Kite

Milano Real Milvus milvus Red Kite

Aguilucho Lag. Occidental Circus aeruginosus Marsh Harrier

Aguilucho Pálido Circus cyaneus Hen Harrier

Aguilucho Cenizo Circus pygargus Montagu's Harrier

Busardo Ratonero Buteo buteo Common Buzzard

Aguililla Calzada Hieraaetus pennatus Booted Eagle

PANDIONIDAE

Águila Pescadora Pandion haliaetus Osprey

FALCONIDAE

Cernícalo Primilla Falco naumanni Lesser Kestrel

RALLIDAE

Rascón Europeo Rallus aquaticus Water Rail

Polluela Pintoja Porzana porzana Spotted Crake

Polluela Bastarda Porzana parva Little Crake

Gallineta Común Gallinula chloropus Moorhen

Calamón Común Porphyrio porphyrio Purple Swamp-hen

Focha Común Fulica atra Common Coot

RECURVIROSTRIDAE

Cigüeñuela Común Himantopus himantopus Black-winged Stilt

Avoceta Común Recurvirostra avosetta Avocet

 

GLAREOLIDAE

Canastera Común Glareola pratincola Collared Pratincole

 

CHARADRIIDAE

Chorlitejo Chico Charadrius dubius Little Ringed Plover

Chorlitejo Grande Charadrius hiaticula Great Ringed Plover

Chorlito Dorado Europeo Pluvialis apricaria European Golden Plover

Avefría Europea Vanellus vanellus Northern Lapwing

 

SCOLOPACIDAE

Correlimos Tridáctilo Calidris alba Sanderling

Correlimos Común Calidris alpina Dunlin

Combatiente Philomachus pugnax Ruff

Agachadiza Común Gallinago gallinago Common Snipe

Aguja Colinegra Limosa limosa Black-tailed Godwit

Zarapito Real Numenius arquata Eurasian Curlew

Archibebe Común Tringa totanus Common Redshank

Archibebe Claro Tringa nebularia Greenshank

Andarríos Grande Tringa ochropus Green Sandpiper

Andarríos Bastardo Tringa glareola Wood Sandpiper

Andarríos Chico Actitis hypoleucos Common Sandpiper

LARIDAE

Gaviota Reidora Larus ridibundus Black-headed Gull

Gaviota Sombría Larus fuscus Lesser Black-backed Gull

STERNIDAE

Pagaza Piconegra Gelochelidon nilotica Gull-billed Tern

Fumarel Cariblanco Chlidonias hybridus Whiskered Tern

 

ALCEDINIDAE

Martín Pescador Alcedo atthis Common Kingfisher

MEROPIDAE

Abejaruco Común Merops apiaster European Bee-eater

 

HIRUNDINIDAE

Avión Zapador Riparia riparia Sand Martin

Golondrina Dáurica Hirundo daurica Red-rumped Swallow

 

MOTACILLIDAE

Lavandera Boyera Motacilla flava Yellow Wagtail

Lavandera Cascadeña Motacilla cinerea Grey Wagtail

Lavandera Blanca Motacilla alba Pied Wagtail

 

TURDIDAE

Pechiazul Luscinia svecica Bluethroat

SYLVIIDAE

Ruiseñor Bastardo Cettia cetti Cetti's Warbler

Buitrón Cisticola juncidis Zitting Cisticola

Buscarla Unicolor Locustella luscinioides Savi's Warbler

Carricerín Real Acrocephalus melanopogon Moustached Warbler

Carricerín Común Acrocephalus schoenobaenus Sedge Warbler

Carricero Común Acrocephalus scirpaceus Reed Warbler

Carricero Tordal Acrocephalus arundinaceus Great Reed Warbler

 

TIMALIIDAE

Bigotudo Panurus biarmicus Bearded Tit

PASSERIDAE

Gorrión Moruno Passer hispaniolensis Spanish Sparrow

ESTRILDIDAE

Bengalí Rojo Amandava amandava Avadavat

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[Capítulo segundo: Los mejores lugares para ver aves >>]