animals can't afford to be choosy about what they eat. 动物们也无权挑剔自己的饮食
They can travel two thirds of a mile a night 它们一晚可以行进1.1公里
that they flow almost like water. 让它们可以如流水般行动自如
and as deserts heat up, they are also expanding. 随着温度升高 沙漠也在不断扩散
If he can't provide them with water, they will leave him 如果他无法提供水源 她们都会离开
if they get nothing to drink, they will be dead within hours. 如果没有水喝 雏鸟会在数小时内曝晒而死
but then vanish almost as quickly as they came. 但以几乎同样的速度消失
they may not have visited for decades. 数十年前去过的水坑