Not sure if it’s functional or not. British Museum describes it as:
The gilt-silver buckle has a rectangular plate with a bird’s head terminal in profile, scrollwork decoration and green glass inlays. The loop is oval, the tongue is hollow and has an animal-head terminal.
The right bit is a tongue rest for the belt buckle with a stylized bird head.
So the bird’s beak is not a functional hook?
Not sure if it’s functional or not. British Museum describes it as: