Water courses can be very different depending on their width, depth of the channel, altitude at which they are located and associated vegetation. Alders, ash, poplars and willows appear in the permanent courses, while in the seasonal courses, almost always dry in the summer, species adapted to the lack of water such as oleander and tamujo predominate.
The main birds associated with the riparian vegetation are Common Nightingale, Melodious Warbler, European Robin, Blackcap, Eurasian Penduline Tit, Eurasian Golden Oriole and Cirl Bunting, as well as nocturnal species like Red-necked Nightjar. On the rivers in the north of the region there are White-throated Dippers and Grey and White Wagtails, the latter being much more widespread throughout wetter areas of the region. On rivers with abundant emergent vegetation, small birds such as the European Reed, Great Reed and Cetti’s Warblers breed, as well as exotic species such as Red Avadavat and Common Waxbill. Where this vegetation is more extensive, populations of Purple Heron, Little Bittern, Water Rail and even scarcer species such as Western Swamphen and Savi’s Warblers occur. There are important colonies of herons and egrets in the riverside trees, some with thousands of birds, where Cattle and Little Egrets, Grey Heron, Black-crowned Night Heron, White Stork and occasionally Squacco Heron and Eurasian Spoonbill nest together. In the sandy banks there are Common Kingfishers and colonies of Sand Martins and European Bee-eaters, whose burrows are sometimes used by European Rollers or Common Rock Sparrows.
Among the SPAs that include river courses, noteworthy are the Azud de Badajoz, Montijo Reservoir, River and pine forests of Tiétar, Riveros del Almonte and Vegas del Ruecas, Cubilar and Moheda Alta.
