Their plumage changes little with the seasons and their nests are easy to spot against the exposed tundra soil.

它们的羽毛几乎不随季节而变化，而它们的巢穴在苔原上裸露的泥土映衬下极易被识别。

It was caused by a particularly hot dry air that coincided with failed farming practices that exposed the top soil to the sun and wind, and created lots of dust storms.

这是由于极度炎热干燥的空气和错误的耕作方式，使表层土壤暴露在风吹日晒之下，于是便形成了许多沙尘暴。