The Bird with the Crystal Plumage (1970) is the second film in what's become known as his Animal Trilogy, even though Nine Tails has no significant animal in it; not even the yellow-eyed cover star. The term refers to the number of possible leads in the investigative part of the story.
There's nothing particularity bad about the film, but nor is there much to get excited about. It's perhaps because the director was still testing the waters, experimenting with levels of violence and plotting. But I suspect it's also in part due to his wishing to appeal to a more international audience.
It might please folks who want a straight thriller with an edge, but anyone wanting a classic Argento experience should look elsewhere.
The music is again by Ennio Morricone; he did all three films in the trilogy.
2 glasses of milk out of 5