Why is a crow the bravest bird in the world?

Why is a crow the bravest bird in the world?
为什么乌鸦是世界上最勇敢的鸟呢？

答案:
Because it never shows the white feather．
因为他从来都不展示他的白羽毛（胆怯）
show the white feather有“胆怯”的意思