Radford Andrew N, Ridley Amanda R
Department of Zoology, University of Cambridge, Downing Street, Cambridge CB2 3EJ, United Kingdom.
Curr Biol. 2006 Sep 5;16(17):1700-4. doi: 10.1016/j.cub.2006.06.053.
In many altricial birds, fledglings disperse when they are no longer fed, and this dispersal marks the end of parental care. In some species, however, young remain in close association with their parents after nutritional independence. Because juveniles are still inferior foragers at this stage, they might benefit from parental assistance in locating good feeding sites, but this possibility remains largely unexplored. Here, we show that parents and helpers in pied babbler (Turdoides bicolor) societies use a recruitment call to direct nutritionally independent, but inexperienced, foragers to particular food patches. Observations and a playback experiment indicated that adult babblers use a "purr" call to recruit group members to a foraging patch. Creation of experimental foraging patches supported observations that individuals tend to give the call when they are foraging on abundant, divisible food sources and when their group contains independent fledglings (youngsters who are no longer fed directly). Fledglings responded to calls more often than adults, who frequently encountered aggression from the caller if they did, and the fledglings gained significant foraging benefits. This is the first study to demonstrate that altricial birds may use recruitment calls to extend parental care past the period of direct provisioning.
在许多晚成鸟中，雏鸟在不再被喂食时就会扩散，这种扩散标志着亲代抚育的结束。然而，在一些物种中，幼鸟在营养独立后仍与父母保持密切联系。由于幼鸟在这个阶段觅食能力仍然较差，它们可能会从父母在寻找优质觅食地点方面的帮助中受益，但这种可能性在很大程度上仍未得到探索。在这里，我们表明，双色斑鸫鹛社会中的父母和帮手会使用一种招募叫声，引导营养独立但缺乏经验的觅食者前往特定的食物斑块。观察和回放实验表明，成年斑鸫鹛会使用“咕噜”叫声将群体成员招募到觅食斑块。实验性觅食斑块的创建支持了以下观察结果：当个体在丰富、可分割的食物源上觅食且群体中有独立的雏鸟（不再直接被喂食的幼鸟）时，它们往往会发出这种叫声。雏鸟对叫声的反应比成年鸟更频繁，如果成年鸟做出反应，它们经常会受到叫声发出者的攻击，雏鸟获得了显著的觅食益处。这是第一项证明晚成鸟可能会使用招募叫声将亲代抚育延长到直接供给期之后的研究。
