I started my marble collecting in 2005 and the "Kingfisher" was one of my first marbles... It was quite some time later I heard it referred to as a "Kro" or "Krow" or "Crow"... After this post was started, I do think "Kro" is probably the most correct spelling...
I have 8 or 9 of those Mibs, only 2 with the long bill... The others do have a wisp of white with a black vein, but no bill...