Very nice. The one with the verdigris (green copper) effect could use some coppery colours to make that clear. Maybe put oranges an edges and the greens is recesses?
The smoothness on the bird's nape still looks a little odd to me. Shouldn't that be rigid? I like the last palette too.
Third palette is my favorite by far. The secondary lighting is much more visible and rather nice.
I'm working on a new palette, to the effect of this:
http://image.shutterstock.com/display_pic_with_logo/56417/56417,1149699185,2/stock-photo-rusty-copper-tiles-1411384.jpg
I think it looks really good, almost Fool-worthy lol but i agree with Perihelion...the palette could be a lot better.
Great design and rendering! I think your palette is a bit boring, though. Try mixing in different colors.
VERY cool. So.. stoned.