 The black swan is almost exclusively herbivorous, and while there is some regional and seasonal variation, the diet is generally dominated by aquatic and marshland plants.In New South Wales the leaf of reedmace (genus "Typha") is the most important food of birds in wetlands, followed by submerged algae and aquatic plants such as "Vallisneria".In Queensland, aquatic plants such as "Potamogeton", stoneworts, and algae are the dominant foods.