Sometimes a portrait only has a lot of important items, and sometimes there are only a few.  Portrait of a Girl with a Parrot does not have as many important items as The Ambassadors.  The most obvious item she has is a parrot.  Why do you think she has a parrot?  Maybe it was just her pet, but maybe it meant something more.  Parrots were expensive, so it could show that she and her family were wealthy.  Do her clothes look expensive too?