Interesting that our field trials (where planted birds are used) are on pigeons in launchers vs. game birds. Our Pointer was none-too-fussed about pointing pigeons, especially in a launcher - but he's getting used to the drill. The pheasant and quail in his "yard" manage to keep him entertained (and still) for hours <G>.
FWIW, there are also trials on "native" (non-released) birds - but if no one finds a bird no one places, them's the breaks!