Wiktionary(0.00 / 0 votes)Rate this definition: upthrust(Noun) an upward thrust. upthrust(Noun) buoyancy. upthrust(Noun) an upward movement of part of the Earth's crust. upthrust(Verb) to thrust something upwards.
Predators, Food and Feeding: Natural predators of winter flounder include sharks, oyster toadfish, summer flounder, striped bass, monkfish and spiny dogfish. When feeding, a winter flounder will lie motionless, partly concealed on the bottom, with its head raised off the bottom, braced by the dorsal fin.
Diet. Ruffed Grouse forage on the ground and in shrubs and trees. They are omnivores, although they feed mostly on plant material. In the winter, they eat the buds of deciduous trees, especially in areas where it snows. The large buds of aspen trees are an important winter food source.