We can see how the Guadalquivir marshlands begin their biological cycle with the first autumn rains. Throughout the year, European and African migratory species find refuge here: ducks, geese, herons, little egrets, spoonbills, avocets, gull-billed terns... they nest and breed in these marshlands. Here too the imperial eagle breeds in April, and in summer the fallow deer's mating displays take place.