they use thermals, rising columns of warm air, to gain height. 可它们会利用热空气 ——呈圆柱形上升的热气流来获取高度

298. and a new opportunity.
     新的机遇
299. The flock stay in close contact by calling one another.
     鹤群通过互相鸣叫保持密切联系
300. Weak from lack of food and water,
     尽管它们缺食少水 日渐衰弱
301. they use thermals, rising columns of warm air, to gain height.
     可它们会利用热空气 ——呈圆柱形上升的热气流来获取高度
302. For many this is their first journey across the Himalayas.
     许多蓑羽鹤都是第一次 踏上穿越喜马拉雅的旅程
303. For some, it will be their last.
     而有些却是最后一次
304. The golden eagles have been expecting them.
     金雕早已企待它们的到来

来自《行星地球 第一季 第二集 Planet Earth S01E02 山地》第 301 行