Oprah and Annie

I agree the whole session is splendid, parrots just offer lovely postures and expressions aplenty, especially when in pairs. And all they need for a wonderful portrait is a naturally green background.

This one was executed truly well - excellent exposure and contrast, perfectly placed focus and sufficient, but not excessive (considering the softness of the plumage) sharpness. The tones are predominately in shade, which pleasantly softens them, but the highlights on the beak and wing feathers add a nice touch of brightness. The colors are simply delightful, which is totally expected from an ara.
Once again, the background is simply ideal for the shot. The contrast between the dark areas and the well-lighted feathers makes the bird stand out. I especially like the few reddish/brownish shades here and there which break up the dominant green and add variety.

My sole remark would be about the composition - animal portraits can be tricky in this regards. As a whole, the cadre is well balanced, but the central positioning is just too plain. I would suggest reducing the empty space to the left, let's say, by half. This way the bird will fill up the cadre without being centralized. Also, the lesser space in front of its face would emphasize on the way it is looking towards the viewer over its shoulder and this will make the picture much more interesting.

My rating is high overall, but not only because of the cuteness of the parrot (and my love for their kind). A good portrait like this requires much more thought and skill from the photographer than it's evident. The author has shown this skill and positively a good vision for the cadre.