VIGILANCE AND GROUP-SIZE IN OSTRICHES
VIGILANCE AND GROUP-SIZE IN OSTRICHES
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DOI：
10.1016/s0003-3472(80)80030-3
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发表时间：
1980-01-01
期刊：
影响因子：
2.5
通讯作者：
BERTRAM, BCR
中科院分区：
文献类型：
--
作者：
BERTRAM, BCR
观察野生鸵鸟单独进食或最多4只鸵鸟为一组进食的情况，并记录它们的警惕性（抬头的时间比例）。个体警惕性随着群体规模的增加而下降，这主要是由于抬起头的频率减少。男性比女性更警惕，主要是因为他们抬起头的时间更长。警惕性更多地受到在场的影响，而不是同伴的影响。对于掠食者来说，不可能预测一个头什么时候会长时间低下。鸵鸟在进食时进行分组，只会略微降低群体对捕食者攻击的脆弱性，但会显著降低个体的脆弱性。
Wild ostriches were observed while feeding alone or in groups of up to 4 birds and their vigilance (proportion of time with the head up) was recorded. Individual vigilance declined as group size increased, mainly through a decrease in the frequency with which the head was raised. Males were more vigilant than females, mainly because they kept their heads up longer. Vigilance was influenced more by the presence than by the vigilance of a companion. It was impossible for a predator to predict when a head would stay down for a long time. Grouping by ostriches when feeding results in only a slight reduction in the group''s vulnerability to successful predator attack, but in a considerable decrease in individual vulnerability.