"'Come autumn sae pensive, in yellow and gray,"

These lines come from a poem/song entitled 'My Nanie's Awa', written by the Scottish poet Robert (Rabbie) Burns (1759-1796). 

Full text

It is generally sung to the tune, 'There are few good fellows when Jamie's awa' '.

Listen to both an instrumental version of this tune and an alternative melody for 'My Nanie's Awa':