We have been down this track a few times before. The male does not begin to acquire blue-black plumage until year 6. Males, we are told, begin to acquire the yellowish bill in year 4. Therefore while we ‘(myself included) tend to use ‘juvenile’ for any distinct sub-adult plumage, it seems sensible to avoid the term for a sub-adult that is demonstrably not juvenile (ie in a later year than first full plumage) in the strict sense. The difficulty lies in separating black-billed green birds, that is in separating females from second and third year immatures, including males. There are various places around Canberra, not just the much-visited ANBG site, offering opportunities for close observation, so it would be good to add to the store of info on plumages and behaviour of young ‘practising’ males.
The below, snapped 28 June, presents something of a poser, in my view. On appearance, I cannot tell if the bird is a female or a year 2/3 male - comments appreciated. The fact that it was bower-tending suggests the latter. The fact that it was bower-painting (inset) in imitation of the adult male seems unusual for such a young bird, but would be even more unusual if it was a female.
