isn't normally on their menu. 通常不会出现在冠斑犀鸟的菜单上

17. And they do so with an unusual ritual...
    为此有一种特别的仪式
18. ..at the entrance to a bat cave that they know well.
    将在它们熟悉的蝙蝠洞口举行
19. This rather curious gift
    这份奇特的礼物
20. isn't normally on their menu.
    通常不会出现在冠斑犀鸟的菜单上
21. But it both demonstrates devotion
    但这样的礼物既是情之所钟的象征
22. and reassures the female that her mate will provide for her.
    又是雄鸟供养伴侣的保证
23. In the coming weeks, she will depend on him
    在接下来的几周 雌冠斑犀鸟

来自《行星地球 第三季 第五集 Planet Earth S03E05 森林》第 20 行