Thanks for the FB. I re-worked the BG and removed the AA on the bird to reduce colors. 

I hope it is better now. 

Your three lighter greens are indistinguishable. They're hard to tell apart even zoomed in.

I think adding new colours like that just for AA is a waste. Hue barely matters for AA, so why not use colours of appropriate values that you already have in other parts of the image?

Bird: awesome

Grass: too flat looking

Sky: well It's a sky.

Not bad, but I think the bird deserved a better BG.