back at their traditional breeding grounds at last. 返回了它们阔别已久的繁殖地

71. Their marathon migration is almost 3,000 miles long
    这场马拉松式的迁徙长达三千英里
72. and has taken them three months.
    耗时多达三个多月
73. Exhausted and starving, they touch down inside the Arctic Circle,
    虽然早己精疲力竭 饥肠辘辘 但它们终于返回了北极圈
74. back at their traditional breeding grounds at last.
    返回了它们阔别已久的繁殖地
75. Snow geese pair for life.
    雪雁一生只忠于一个配偶
76. As soon as couples arrive, they must stake a claim to a nesting patch.
    一对雪雁来了之后就必须取得自己的筑巢地
77. Ideal sites are in short supply and quarrelsome neighbours are all around.
    理想的地方寥寥无几,邻里纠纷时常发生

来自《行星地球 第一季 第七集 Planet Earth S01E07 伟大草原》第 74 行