And a century ago, the bison were reduced to barely 1,000. 一百年前 野牛的数量曾锐减至不到一千
and grass can only grow here for a few months a year. 这里的草儿只有几个月的生长期
But further south, summers are longer and the grasslands flourish. 但是在更远的南边 夏天的时间更长,草原更加茂盛
until the summer ends and they're forced to head south for the winter. 直到夏天结束 它们才会被迫南迁过冬
At the goose colony, it's high summer and eggs are hatching. 在雪雁的领地,此时正值盛夏 小鸟正在孵化
The wolf panics the herd, and the weak and young are singled out. 狼从受到惊吓的鹿群中寻找老弱孤残
Biting flies and the quest for new pasture drives the migration ever onwards. 会叮咬它们的苍蝇以及为了寻找新草场, 驱使它们不停的向前迁徙
and throughout this time she will be very vulnerable. 而在这三周里 它将变得易受攻击
and there are fewer predators than further south. 而且这里的掠食动物比南方少多了
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