The Brazo del Este (East Arm) is a man-made modification of the Guadalquivir river. It is one of the original arms that the river divided into on its journey through the marshes. Despite the amount of human intervention since the beginning of the last century, it has become an exceptionally important wetland area for birdlife.

The Brazo del Este runs for 39 kilometres alongside flat land and in successive meanders (bends), accompanied by abundant vegetation and a number of birds. It is a sight worth seeing, especially in the summer time, when it becomes a vital shelter for species fleeing Doñana, due to the depletion of the water reserves there.

The Brazo del Este is a paradise for bird watchers. Because of its positioning between Doñana, the marshes and the Dehesa de Abajo lagoon, it is possible to see ducks, birds of prey and both summer and winter migrants. The list of species is endless: purple heron, mallard, northern pintail, shoveler, teal, western swamphen (possibly the most abundant population in Europe), European rail, spotted and little crake, moorhen, bittern, squacco heron, marbled duck (for whom the Brazo del Este is an important nesting area), egret, grey heron, cattle egret, white stork, red kite, buzzard, short-eared owl and western marsh harrier. You can also see the black-crowned night heron, seagulls and more.