评论：
2018-11-24.
Андрей Баздырев: Young Common Tern (Sterna hirundo): the base of the bill is orange (in the young Little Tern - the bill is almost completely black, in adults in summer it is yellow with a black tip, in winter - black), the legs are orange (in the Little Tern - yellow).
2018-11-25.
a龙: Translation from Андрей Баздырев:
普通燕鸥幼鸟：喙基橘色（白额燕鸥幼鸟喙基很明显为黑色；成鸟夏羽喙黄、喙尖黑，冬季黑色），腿橘黄（白额燕鸥黄色）。
