Where did the Gaddi shepherds live? Describe the seasonal movement of the Gaddis

The Gaddi shepherds of Himachal Pradesh spent their winter in the low hills of Siwalik range, grazing their flocks in the scrub forests.
By April, they moved North and spent the summer in Lahul and Spiti. When the snow melted and the high passes were clear, many of them moved onto higher mountain meadows. By September, they began their return movement. On the way they stopped in the villages on Lahul and Spiti, reaping their summer harvest and sowing their winter crops. Then, they descended with . their flock to their winter grazing ground on Siwalik hills. Next April, again they started their march with their goats and sheep, to the summer meadows.