In older times, the beginning of May was when many groups in Scotland and Ireland took their flocks and herds to higher pastures for the summer. There were several practical reasons for making this move.
First, sheep do this by instinct. Second, the newly planted crops needed protection from the grazing animals. Third, the practice made good use of land that was not suitable for farming but sufficient for grazing.
In Ireland, going to the upper pastures was called buaile or booley; in the Highlands, it was known as the sheiling. In both cases, the same term referred to the huts used in summer.
Myself, my spouse, and my children,
My tender children and their beloved mother at their head.
On the fragrant plain, on the gay mountain sheiling,
On the fragrant plain, on the gay mountain sheiling.