On a number of occasions I have seen 10 parrot species in the North East corner of Cumberland State Forest in Castle Hill.
The list for parrots in that location is as follows :
Galah
Long-billed Corella
Little Corella
Sulphur-crested Cockatoo
Rainbow Lorikeet
Musk Lorikeet
Scaly-breasted Lorikeet
Little Lorikeet (occasionally)
Australian King-Parrot
Crimson Rosella
Eastern Rosella
Best time is in the morning when the sun starts to shine in the top of the trees.
Regards
Barry Lancaster