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Facultative lagoon (polishing pond) providing tertiary treatment after a constructed wetland in Hamburg-Allermöhe, Germany. Overflow from the facultative lagoon may be routed through one or more polishing ponds supporting lower populations of anaerobic micro-organisms and a higher proportion of aerobic organisms adapted to survival in lower concentrations of organic material.
Plesiosaur gastroliths from Tropic Shale. A gastrolith, also called a stomach stone or gizzard stone, is a rock held inside a gastrointestinal tract.Gastroliths in some species are retained in the muscular gizzard and used to grind food in animals lacking suitable grinding teeth.
Male and female yellow-billed ducks have a statistically significant difference in life spans. Male ducks live for 4 years and 4 months on average while female ducks only live for just over 3 years. As such the difference in survival rate is statistically significant as well. 79% of males survive any given year while only 72% of females do.
They are mostly benthic and live within the periphyton, the layer of tiny organisms and detritus that is found on the seabed and the beds of other water bodies. The majority live on and between particles of sediment or on other submerged surfaces, but a few species are terrestrial and live on land in the film of water surrounding grains of soil.
The Pacific black duck is mainly vegetarian, feeding on seeds of aquatic plants. This diet is supplemented with small crustaceans, molluscs and aquatic insects. Food is obtained by 'dabbling', where the bird plunges its head and neck underwater and upends, raising its rear end vertically out of the water.
The canvasback feeds mainly by diving, sometimes dabbling, mostly eating seeds, buds, leaves, tubers, roots, snails, and insect larvae. [3] Besides its namesake, wild celery, the canvasback shows a preference for the tubers of sago pondweed, which can make up 100% of its diet at times. [10]
This duck feeds on vegetation by grazing or dabbling [4] and to a lesser extent on small fish, invertebrates, and seeds. It can become a problem to rice farmers. Knob-billed ducks often perch in trees. They are typically seen in flocks, small in the wet season, up to 100 in the dry season. Sometimes they separate according to sex. [9]
The American black duck is darker than most mottled ducks, and its wing-patch is more purple than blue. The behaviour and voice are the same as the mallard. Mottled ducks feed by dabbling in shallow water, and grazing on land. They mainly eat plants, but also some mollusks and aquatic insects.