with perfect poise. 完全悬停

346. and one of the most streamlined bodies of any animal,
     以及动物中最流线型的身体
347. making them the world's greatest swimming birds.
     这使它们成为 世界上最伟大的会游泳的鸟类
348. Scanning for fish, it hovers like a hummingbird...
     寻找鱼类时 它们像蜂鸟一样
349. with perfect poise.
     完全悬停
350. In contrast, the cold-blooded iguanas are slow and sluggish...
     相比之下 冷血的海鬣蜥动作迟缓
351. restricted to feeding on low-energy kelp...
     只能以低能量的海藻为食
352. at the whim of the currents.
     还要看洋流的脸色

来自《我们星球上的生命 第一季 第六集 Life on Our Planet S01E06 灰烬中重生》第 349 行