I'm listening to this:
http://www.youtube.com/watch?v=DNT7uZf7lew#normal
In a futile attempt to hear how the writers of that other song were able to claim against them. Can anyone else hear it? 
Pickerington Elementary Choir "Kookaburra"It helps if you know the original, but listen to the melody from the flute. The third phrase in the intro is the 2nd phrase of the Kookaburra song and after the choruses, phrases 2 and 4 are the first 2 phrases of the Kookaburra song. Add to the the fact that he's sitting in a tree it links to the lyric "Kookaburra sits on the old gum tree". We've all known about it for about 20 years, I'm surprised it too so long for them to sue. However the Men at Work song is a classic.
Apparently it happened like this.....(according to a poster on youtube)
1) Author grants tacit permission for the band to use parts of her song in the 1980s.
2) Author dies.
3) Legal troll buys the rights to the song in the 1990s.
4) Legal troll sues the band who released the song in the *1980s*.