Yes Ann it appears to be the most common host in
  the Sydney region despite not being listed in Brooker and Brooker " Cuckoo
  Host Species in Australia".
   
  Bruce Cox.
  
  Yesterday was a day for koels.
  Firstly we saw an adult female in the Rose Hill
  NSW area and then later in the morning at Silverwater we watched with interest
  as a red wattlebird divided her time between educating her offspring on how to
  feed in grevillia and then racing back to feed her other dependant,
  incessantly demanding koel in the adjoining tree.
  Can anyone please tell me is the Red Wattlebird
  the usual host for the Koel
   
  Regards,
  Ann