White Throated Sparrows Suddenly Singing New Song Across Canada

An extraordinary change has come to White Throated Sparrow songs. In BC in the mid-nineties, a new song was being heard. By 2004 it was adopted across half of Alberta.  In 2019 it was spreading through Quebec.  For such a baked-in distinctive to change so rapidly is astonishing.
Was:  "Oh my sweet Canada, Canada, Canada" and is now, "Oh my sweet Cana-Cana-Cana-Canada".
Crowd-sourced recordings available on the internet fueled this story.