A Google search reveals these references:

Nations And States: An Enquiry Into The Origins Of Nations And The Politics ...
By Hugh Seton-watson refers to it as "the well-known

Hebridean's prayer "

The Xenophobe's Guide to the Scots
By David Ross refers to it as
The Crofter's Prayer

Scottish Tradition (RLE Folklore): A Collection of Scottish Folk Literature
By David Buchan refers to it as

The Skyman's Prayer

So they all refer to it as a prayer and not a song.