kagu and tropicbirds

[Ken Kinman]

Dear All,
      The origins of the kagu of New Caledonia has always been a mystery.  I have thought it looks somewhat like a tern or tropicbird that flew there and became more terrestrial (semi-flightless).  Anyway, I just saw that the kagu and tropicbirds are both members of the recently proposed clade Metaves (a subclade of Neoaves), while terns are in the other subclade (Coronaves).  This makes me wonder if the kagu evolved from some (no doubt extinct) form of tropicbird.  Does this sound plausible?  It makes more sense to me than the kagu being a Gondwanaland relict.
  ----Cheers,
            Ken Kinman