Why are male birds usually more beautiful than female birds?

because in that way the male birds can attect the female birds' eyes in order to make the female birds love the male birds .

为什麽雄性的鸟类比 雌性的要漂亮?。
这样能吸引雌性的注意,可以繁育后代

为什么雄鸟通常比雌鸟漂亮