A variation I heard was..

Take care of your web-footed friends
For that duck may be somebody's mother
He lives in the stream by the swamp
Where the weather is awfully domp
Well you may think that this is the end
Well it's not and to prove that I'm no liar
I'll sing it to you once again
Only this time it'll be a little higher

Then you do sing it again, a tone and a half higher

Repeat until almost out of range

then do Lindswinder's verse

regards

Splott man