The pictures come off a little soft to me, but that might just be my eyes (after staring at a computer all day, I tend to question my eyesight)
The colors are beautiful, but I think composition is what's lacking....
Parrots are long birds, I would have taken these shots vertically. You are cutting out part of the parrots that's essential IMO....their tails. I look away feeling like you gypt me! haha. If you have the chance to do this again, definitely take them vertically and maybe do a couple that aren't centered in the frame also!
"Remarkable bird, the Norwegian Blue, idn'it, ay? Beautiful plumage!"
Sorry couldn't help myself. You say parrot, I say... well you get the idea.
I do agree that these need a little more bird in them. Either verticle or an interesting landscape. Looking at the first two, I feel like they're just a tad underexposed. The white around the eye might pop a little if you upped the exposure just a hair (As Kmh said, fill flash would have helped a lot). They also do feel a little soft.
Well, from what I'd reckon is off, I would say that the shots are ever-so-slightly blurred, I think from too slow a shutter speed (A tip would be to use a shutter speed of above your focal length, e.g. if you had a 300mm lens, you would want to use a speed of 1/300 or above), and that the birds are slightly dark compared to their background. This can be remedied by selecting the bird using Photoshop and adjusting the levels of only that selection. Of course, you could get it right in-camera by using a burst of fill-in flash.
However, I would say that these are some very good photographs and, with just a little tweaking, I'd be more than happy to have one on my wall. It's only got a couple of minor flaws that can be easily fixed. So nice work! What lens did you use? I can never get the background of any bird enclosure that blurred .