Water rail
Water rails are omnivorous, although they mainly feed on animals. These include leeches, worms, gastropods, small crustaceans, spiders, and a wide range of both terrestrial and aquatic insects and their larvae. Small vertebrates such as amphibians, fish, birds and mammals may be killed or eaten as carrion. Vertebrates are impaled with a strike of the bill which breaks the prey's spinal cord. Plant food, which is consumed more in autumn and winter, includes the buds, flowers, shoots and seeds of water plants, berries and fruit. In south Asia, paddy (harvested rice kernels) may sometimes be eaten. The young rails are fed mainly on insects and spiders. Food obtained on land or from mud is normally washed in water before it is eaten. After rain, rails may probe soft ground for earthworms. This species will occasionally feed in the open even when not forced to do so by cold weather; Edmund Meade-Waldo described seven rails feeding in an open meadow. Despite its skulking nature, the water rail appears to thrive in captivity when fed on animal food such as raw meat or earthworms; one individual was taught to jump for worms suspended from a fishing rod.
Mollusca
Most molluscs are herbivorous, grazing on algae or filter feeders. For those grazing, two feeding strategies are predominant. Some feed on microscopic, filamentous algae, often using their radula as a 'rake' to comb up filaments from the sea floor. Others feed on macroscopic 'plants' such as kelp, rasping the plant surface with its radula. To employ this strategy, the plant has to be large enough for the mollusc to 'sit' on, so smaller macroscopic plants are not as often eaten as their larger counterparts.
Filter feeders are molluscs that feed by straining suspended matter and food particle from water, typically by passing the water over their gills. Most bivalves are filter feeders.