and keen eyes have spotted movement. 军舰鸟锐利的眼睛正在搜寻

270. But where?
     可在哪里呢?
271. Those that fly above the ocean must be able to read the signs of fresh supplies, or perish.
     飞越海洋的鸟类必须懂得寻找食物的踪迹, 不然就意味着死亡
272. A hundred miles from the Mexican coast,
     距墨西哥海岸100英里,
273. and keen eyes have spotted movement.
     军舰鸟锐利的眼睛正在搜寻
274. Sailfish, three meters long, are closing in on prey.
     3米长的旗鱼正在接近猎物
275. They will only use just enough energy to make their kill
     它们只用恰到好处的力量来猎杀
276. never wasting a fin stroke.
     从不贸然浪费力气

来自《行星地球 第一季 第十一集 Planet Earth S01E11 海洋深处》第 273 行