"Denizen" of the swamp, heh? We always sang, "Be kind to the *residents* of the swamp." Not that it makes much difference...

Be kind to your web-footed friends
For a duck maybe somebody's mother
Be kind to the cop on the beat
'Cuz he may be Dick Tracy's brother
Be kind to the residents of the swamp
Where the weather is co-old and dah-ahmp
You may think that this is the end
Because it is

I can hardly claim that my family's version (wherever it came from) is definitive, and certainly can't argue with Fred Allen, but I find that this version "fills out" the tune better than the others I've seen here.

That is, "You may / think that this / is the end" comes on a rising crescendo in the penultimate line, and "Because it is" is quite emphatic and gets you *almost* to the end of the actual tune. In fact, if you repeat "because it is" three times, you *do* sing the entire Souza melody. (Only one of us siblings was that anal-retentive.)