African Penguins Spheniscus demersus, Bait Balls and the Allee Effect
African Penguins Spheniscus demersus, Bait Balls and the Allee Effect
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非洲企鹅 Spheniscus demersus、诱饵球和阿利效应
DOI：
10.5253/078.100.0113
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发表时间：
2012
期刊：
影响因子：
--
通讯作者：
L. Pichegru
中科院分区：
文献类型：
--
作者：
P. Ryan;Lloyd C. Edwards;L. Pichegru
我们报道了非洲企鹅（Spheniscus demersus）的群体合作觅食行为。观察到大约25 - 165只非洲企鹅组成的群体环绕着中上层鱼类群游动，有时会迫使它们游到水面。在这种行为过程中，在任何特定时间都有66 - 75%的企鹅在水下。较少数量的非洲企鹅也会加入海角塘鹅（Morus capensis）和海角鸬鹚（Phalacrocorax capensis）的觅食群体，但当数量少于这些物种时，似乎不会围捕鱼群。由于种群数量持续快速减少，非洲企鹅被列为濒危物种。如果群体觅食对非洲企鹅有利，随着群体数量变得过少，无法形成足够密度的鸟类组成觅食群体，它们不断减少的种群可能会受到阿利效应的影响。
We report co-operative group foraging in the African Penguin Spheniscus demersus. Groups of approximately 25–165 African Penguins were observed circling schools of pelagic fish, sometimes forcing them to the surface. During this behaviour 66–75% of penguins were underwater at any given time. Smaller numbers of African Penguins also joined foraging groups of Cape Gannets Morus capensis and Cape Cormorants Phalacrocorax capensis, but did not appear to corral fish schools when outnumbered by these species. African Penguins are listed as Endangered due to ongoing rapid population decreases. If group foraging confers an advantage to African Penguins, their dwindling populations may suffer from an Allee effect as colonies become too small to support sufficient densities of birds for foraging groups to form.