Hmmm- just looked at the A. B. Patterson poem. I guess he and all others who wrote and followed with various changes, weren't aware of the one true, original and incomparable 'correct' version.

Oh, well, them Aussies cain't be trusted with the English language.

Australia's on the wallaby
Oh listen to the cooey,
The kangaroo he packs his port
And the emu shoulders bluey,
The curlew sings his lonely tune
Beside the long lagoon,
And the brolga does his last-lay dance
To the lyrebirds mocking tune.