Oh, I think Pip could be a smart bird, if he exercises his mind enough.

I have noticed that he does move physically slower than Coco, which is probably also be a part of the brain damage he got from malnutrition, which is most likely delaying the connection between thought and action. Either that, or he's hesitant about everything.

Coco has a history of competing with other birds for goodies, and traveling around the bird room doing what he pleases. I don't know what Pip's life was like before you got him, but if his activities were more restricted then he doesn't have the experience and skills that Coco has. But he can develop his skills over time by interacting with Coco and you, and just generally having the opportunity to do things.