From 9-foot tall ostriches to albatrosses with gargantuan wingspans, here are some of the biggest birds in the world.

科学家们首先佩戴独特的面罩诱捕了这些鸟类，随后将其标记释放。他们观察到，“记仇”的短嘴鸦会持续用刺耳的声音“责骂”并围攻佩戴同样面罩的人，不论他们的体型、年龄、性别或步态如何。与此同时，卸下伪装、不再佩戴该面罩的真正捕鸟者却很少受到围攻。

Peru draws tourists eager to explore the remnants of South America’s ancient civilisations. There’s much to uncover in this ...