Ingela, I'm attaching a couple of pictures of one bird of the pair that I had. The birds have been a mystery to me. They have teal green in the glass around the gray middle. Leslie Pina shows birds like these on pg 95 of her book Fifties Glass. She writes they are possibly Seguso, but I don't think that they are. Another pair of this design was sold on eBay about two years ago. They had a partial green label that the seller said was Barovier & Toso, but I was not sure because the label was not in good shape. Maybe someone in the group will recognize the birds.
Reviving this old thread with some recent news. I think this gray effect bird is VAMSA. I found a couple of birds -- one with a similar gray effect that had a VAMSA label and another that was of this shape that had a typical VAMSA sfumato internal decoration. I'm fairly confident of the attribution. Thought I would update this old record about the green bird. I've been looking for an attribution for years. The green bird is on page 2 of this thread.