人们一直奇怪牛鹂为何能够成功地把自己的蛋留在其他鸟类的巢中,而其他鸟就会帮其抚养幼鸟。为什么鸟巢的主人不把陌生的鸟蛋扔出去?现在研究者们似乎找到了答案——如果鸟巢的主人拒绝陌生的鸟蛋,牛鹂就会回来捣毁这个鸟巢。本周的《美国国家科学院院刊》网络版上报道了褐头牛鹂的这种“黑手党行为”。“在我们的观察地点进行黑手党行径的是雌性 People have been wondering why the burdock can successfully leave its eggs in the nests of other birds, and other birds will help raise the young birds. Why does the owner of the nest not throw out strange eggs? Now researchers seem to have found the answer - if the owner of the nest rejects a strange egg, the calf will come back and destroy the nest. This week’s “The Proceedings of the National Academy of Sciences” online version reported on this kind of “mafia behavior” of the brown calf. “The mafia’s behavior in our place of observation is female