Lyrics brought to you by Segnbora-t

According to all the web sites I've looked it up on, a traditional Australian song with no known author. I've often heard it sung as a round.

Kookaburra sits on an old gum tree,
Merry, merry king of the bush is he.
Laugh, Kookaburra; laugh, Kookaburra --
Gay your life must be.