In fact, one of the largest flying birds on earth, the mute swan, there are about 5 birds around the world that approach that size, that mass.

• 哑天鹅一种原产于欧洲和亚洲并且大范围地传入其他地方的白色天鹅（疣鼻天鹅），喙为黄色，根部有一个黑色的圆形突起，比大多数天鹅鸣叫少得多