by exploiting the petrels' desperate need for bare rock. 它们知道利用海燕必定寻找裸岩筑巢的弱点

47. But the skuas have not chanced upon the petrels, they've been waiting for them.
    但是贼鸥碰到海燕并非机遇使然, 它们早就等着下手
48. These birds do not need to go to the ocean for their food.
    贼鸥不需要到海洋里捕食
49. The skuas can survive further south than any other predator
    与其他猛禽相比 贼鸥的厉害在于它能在地球的最南端生存
50. by exploiting the petrels' desperate need for bare rock.
    它们知道利用海燕必定寻找裸岩筑巢的弱点
51. Even at the height of summer,
    在南极洲 即使是盛夏
52. less than three per cent of Antarctica is free of ice,
    南极洲也只有不到3％的地方没有被冰封
53. and nearly all of that exposed rock is found in one place,
    几乎所有的裸岩都集中在同一个地方

来自《行星地球 第一季 第六集 Planet Earth S01E06 冰雪世界》第 50 行