I am late in this dscussion, Nick, and I know you
said it was on the lower slopes of Mt Buffalo, and coming from a
tall Eucalypt.
My trouble is, your description of the call reminds me entirely
and almost exclusively of a Little Grassbird.
http://www.birdsinbackyards.net/species/Megalurus-gramineus
Click on the sound file on the right hand column.
Was there a swampy area anywhere, nearby, as the call can carry
deceptively. Perhaps the other side of the Gum Tree?
To my ears, the Brush Cuckoo does not fit your description - not
even close, as I read your words:
- Three
equal notes, the second slightly lower than the first and
the third slightly higher than the first, then the same
three notes repeated at a slightly higher pitch, then
repeated again at a higher pitch again
http://www.birdsinbackyards.net/species/Cacomantis-variolosus