A pair of noddy terns fly close together over the island on the reef.
一对白顶玄燕鸥在礁石岛上空比翼而飞q!=hRc679tKVC,。
They are two mates, reaffirming their bond.
它们是在重复确认伴侣关系bHi~]=9j]F5vH54。
Noddies signal to each other continually during courtship,both in the air and after landing.
求偶期的白顶玄燕鸥会不停地表演，无论是在空中还是地上TMTD)&kvG^J!kZ|6。
Once in the trees,the performance changes.
到了树上的燕鸥的表演方式也随之改变U|ofnJ;XjQchHXm。
They bow their heads repeatedly.
它们不停地相互点头ioon-0-!EIO#lNXExD.k。
It's pretty clear how they got their name.
这也是人们又叫它点头燕鸥的原因pwLA6JIwc|Z_)2)=。
To enforce their relationship,the male has to collect nesting materials,and the females are famously fussy,so he chooses his present carefully.
求偶关系成功后，关系还需要经营eZZVikIB4PEOWYfCF@x!。雄燕鸥的任务是收集筑窝的材料aagjFOZ!zQ#MgDK。而雌燕鸥在这方面极为挑剔，礼物得精挑细选];ZPn5p)Qo!n。