I have a picture of a swan with a Decora Import label that looks almost just like your swan except that it has a small crest, instead of the thicker one that yours has. All Decora things I've been able to identify have been AVeM, so the swan I have in the picture is probably AVeM. I would put the picture on, but it isn't mine. The wings are just like your swan and the bill is small like your swan's. It may be that AVeM just made a swan with a Salviati-Toso like crest. I agree with Tami that the head looks Toso.
These swans were made with different types of bowls. Some of the bowls are diamond-quilt (balloton molded), others are swirled, and others have glass with spoke like ribs coming from the pontil area. Others are plain. I use the wings and crest to make a guess at who did a swan, but it is not fool-proof. For example, there are AVeM swans that have separate wings. I have sold a lot of the swans salts in the past. I usually just called them Venetian if they didn't have a label. There are few that I have been totally sure about, which is why there are so few of them in the zoo.
For your swan -- I have the feeling that it is AVeM despite the crest. That AVeM is a tricky company. They did everything, often modeling their work on things done by other companies.