Ok, here´s the real comparison of how "Bird" stands before and after this aspect ratio issue.
The screenshot below is comprised of my BU DVD and a review from the French (Wild Side) DVD.
BU DVD:
Wild Side DVD:
The review of the French DVD states the following:
"So we will proceed in chronological order, beginning with the first film directed by Argento, first in his Animal Trilogy, called "The Bird With The Crystal Plumage". And we start very bad for an independent and absurd reason. Responsible for this technical fiasco is Vittorio Storaro, Director of Photography of the film, that made us suffer for years with Apocalypse Now, decided as he explains in an interview on the extras, crop movie from 2.35 to 2.1 for aesthetic reasons to convert the image to the small screen. To listen to his pompous and almost mystical explanation could almost believe it was in good faith but when viewing the film the result is catastrophic. Composition loses much scope because unnecessary cropping, unpublished until now for this movie. All existing editions respected the aspect ration. Worse yet, beyond the crop, there´s an unjustified impression of seeing an 4/3 image in zooming effect, with details and colors suffering greatly. Despite his talent, this type of megalomaniac move destroys much of the composition work of Argento. How has this escaped Argento and the various technicians who viewed the result remains a great mystery. In any case, avoid this edition at any costs. The best version of the bird... remains for now the U.S."