The normals are reversed. With P6, you can check "normals forward" and fix it. I don't think there's any way to fix it in P5. I suspect if you reverse the normals with the grouping tool, the top of the wings will then be black.

This is an old model, made for Poser 4. Poser 4 didn't care about reversed normals. A lot of old models have this problem, unfortunately.