CORACIIFORMES: Coraciidae
Eurystomus orientalis
The immature Dollarbird has a duller plumage than the adult bird and also sports a blackish bill.
Thinking back on the road-trip Nikki and I did from Brisbane to Cairns in late April I don't recall seeing any adult Dollarbirds, only a few immature ones which makes me think the adults had already migrated North back to Papua-New Guinea and Indonesia, leaving the young ones to find their own way when ready.