The Tagus and Guadiana rivers are largely dammed as they pass through Extremadura. Furthermore, the scarcity of water in the summer months has led to the construction of small reservoirs and ponds. In fact, Extremadura is the Spanish region with the most inland coastline.
On the islands of these reservoirs there are breeding colonies of Little and Gull-billed Terns, Collared Pratincole, Black-winged Stilt, Little Ringed Plover and occasionally Common Tern. Great Cormorant has started to breed as well. On the walls of the dams, Crag Martins and sometimes Blue Rock Thrush, Black Wheatear and Rock Buntings can be seen. Little and Great Crested Grebes, Eurasian Coots and sometimes Whiskered Terns and Northern Lapwings nest in pools with floating vegetation. And among the ducks, Gadwall, Northern Shoveler and occasionally Red-crested and Common Pochards breed. Waterfowl increase in winter, with notable populations of Mallard, Northern Pintail, Eurasian Wigeon, Gadwall, Northern Shoveler, Common Pochard, Tufted Duck, Eurasian Teal and Red-crested Pochard. Wintering populations of Great Crested, Little and Black-necked Grebes are important in some places. There are also roosts of Common Crane, gulls and Great Cormorant. During migration, Black Stork assemble in large flocks and Osprey can be seen regularly. Among the SPAs with reservoirs and ponds, the Orellana Reservoir and Sierra de Pela stand out, Zorita Plains and Sierra Brava Reservoir, Los Canchales Reservoir, Montijo Reservoir, La Serena Reservoir, Arrocampo Reservoir, Brozas Reservoir, Borbollón Reservoir, Alcántara Reservoir, Talaván Reservoir, Valdecañas Reservoir, Valuengo Reservoir, Gabriel y Galán Reservoir, Vegas Altas Reservoir, Llanos and Lagoon Complex of La Albuera, Lagoon Complex Egido Nuevo and Charca de la Dehesa Boyal de Navalmoral.
