一种白色北美洲天鹅（哨声天鹅或小天鹅天鹅属）有柔和、充满乐感的象喇叭似的嗓音，黑喙，底部带有一黄点。
A white North American swan ( Olor columbianus ) having a soft , musical trumpeting voice and a black beak with a yellow spot at the base .
天鹅属