Note Ornamental keel mixed wire and cast parts.I believe this one is in the British Museum . cast plated metal.
From the Portrait of a Man with a Lute at the Maritime museum Greenwich by
Hans Holbein the Younger (c. 1497 – between 7 October and 29 November 1543) was a German artist and printmaker who worked in a Northern Renaissance style. He is best known as one of the greatest portraitists of the 16th century'
we can see an earlier 16th Century Buson whistle which is in already in the developed shape still used today. I thank Mr. Bron Larner for his comment .