産卵中のトウゴロウイワシ科魚類, Menidia menidiaの鳥類および水中捕食者による捕食

概要

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Observations were made of predation on Atlantic silversides, Menidia menidia, during their spawning runs in the intertidal zone of an estuary in South Carolina. Several fishes and avian predators captured M. menidia. Snowy egrets, Egretta thula, and Great egrets, Casmerodius albus, were the most dominant avian predators. We found specific differences in catch mode and actual predatory pressure for the two wading birds. Before the onset of spawning runs, Snowy egrets often made hovering catches which were inefficient, while Great egrets always made standing catches, striking at M. menidia from a standing position. Once a spawning run began, Snowy egrets ceased hovering and both Great and Snowy egrets frequently struck at fish from a standing position. Because of inefficiency in catching prey prior to a spawning run, Snowy egrets always remained unsatiated after a run had ended. A Great egret was satiated after consuming 114 fish (42% of its body weight) during a run. Intraspecific disturbances were often observed in both Snowy and Great egrets. Interspecific interaction did not present a serious problem to the subordinate species, Snowy egret.
日本生態学会の論文
1984-12-30