The Odiel Marshes are a large tidal wetland located at the joint mouth of the rivers Tinto and Odiel, formed by recent sands, silts and clays modeled by the tides. It is one of the most extensive tidal marshes in Spain and brings together a mosaic of spouts, pikes, salt marshes, islands and intertidal strips with great biological richness. It has been recognized as a Biosphere Reserve since 1983 and as a Natural Site since 1984, as well as a SPA and Ramsar site. From the points of visit a very open landscape can be appreciated, with wide horizons and constant changes with the tide. The main interest is in bird watching: more than 250 species use this estuary as a passage, feeding or wintering area, with special value for migratory birds between Europe and Africa. It also highlights the contrast between port activity and the natural character of the estuary. The protection status and its role as an ornithological enclave explain its regular presence in nature guides of Huelva. Access is concentrated in public use areas and interpretive itineraries linked to the visitor center. The best time for birding is usually from autumn to spring, when the presence of waders, flamingos and other wintering or passing species increases; at dusk the light is especially favorable for photography.
