Metz Karen J, Prior Kent A, Mallory Mark L
Department of Biology, Carleton University, K1S 5B6, Ottawa, Ontario, Canada.
Oecologia. 1991 Mar;86(1):57-61. doi: 10.1007/BF00317389.
We examined whether individual cattle egrets (Bubulcus ibis) base their decisions of where to forage, and how long to stay in a patch, on the behavior of other flock members. Cattle egrets commonly forage in flocks associated with cattle and capture prey at higher rates when they do not share a cow with another egret. Foraging egrets provide cues of the location of prey and their success in capturing prey. Therefore, there is the possibility of information transfer between egrets in a flock. We predicted that egrets should only move to occupied patches when the resident was capturing enough prey that it is profitable for the invader to share the patch or take over the patch. However, egrets did not seem to decide where to forage based on neighbors' rates of energy intake, but rather on the presence or absence of conspecifics in a patch. We also predicted that an egret should remain in a patch until its rate of energy intake dropped to or below the average rate for other egrets within the flock. However, egrets that were foraging more efficiently than the average rate for the flock switched patches sooner than less efficient foragers. Egrets did not appear to increase foraging success by gaining information on patch quality from neighbors.
我们研究了牛背鹭个体是否会根据其他群体成员的行为来决定在哪里觅食以及在一个觅食区域停留多长时间。牛背鹭通常成群觅食，与牛群为伴，并且当它们不与其他鹭共享一头牛时，捕食率更高。觅食的牛背鹭会提供猎物位置以及它们成功捕获猎物的线索。因此，群体中的鹭之间存在信息传递的可能性。我们预测，只有当常驻者捕获到足够多的猎物，使得入侵者共享该区域或接管该区域有利可图时，鹭才会转移到已被占据的区域。然而，牛背鹭似乎不是根据邻居的能量摄入率来决定在哪里觅食，而是根据一个区域内是否有同种个体来决定。我们还预测，一只鹭应该留在一个区域，直到它的能量摄入率降至或低于群体中其他鹭的平均水平。然而，觅食效率高于群体平均水平的鹭比效率较低的觅食者更早地更换觅食区域。牛背鹭似乎并没有通过从邻居那里获取有关区域质量的信息来提高觅食成功率。
