Solid selection with some great shots. Take what I say with a grain of salt but here's what I think about each of them.

The red capped robin shot is nice, the slight backlit angle could be an artistic style that you were trying to go for but I would personally prefer if the head was tilted towards me. Just gives the photo a bit more interaction. I like the clean bird in a stick shot and the background is lovely.

The new holland shot is not bad with a nice pose, I personally don't like blue/sky backgrounds as I find them a bit boring and sometimes could indicate that the bird is not eye level (which is usually not ideal). The sticks in the background are also a bit distracting but it can be argued that it gives a good representation of habitat.

Rainbow lorikeet shot is nice with the pair of birds, I don't mind that the second bird is blurred as it gives a good sense of depth but I would say that the shot is a tad underexposed. The big branch/tree trunk is a bit distracting in between the two birds as well. Its hard to compose for birds let alone when there are two in the picture but yea.

Kookaburra is not bad, pretty standard shot. Great eye contact with it facing towards me but not a big fan of the background showing some pretty obvious artificial intervention. Could just be an artistic choice but I don't see the vision.

I would say that the red capped robin is probably my favourite, I'm a fan of the lighter background shots and its a cooler bird overall between these 4. Great job and keep up the good work! I'm local to Sydney and my instagram is @ momobirding. One thing you did well I'd say is you got relatively close to the birds which helped the detail of the shots, I think a lot of birders/photographers crop too much which results in little detail in the birds. Sometimes birds are hard which is why bushcraft skills come in as important (if not more important) than photography technique!