Genetic nomenclature. In this case, the black is diluted by blue. What you have is an e^b based bird with silver (probably, but not for certain) the pattern gene and a copy of blue. A silver partridge is the same except for the blue.idk if a silver partridge /silver blue partridge is a different color but someone said my roo is a silver blue partridge and someone else told me its a silver partridge idk if these two are different colors
This is similar to silver blues, which are birchen based plus blue. And of course, birchen is a crow wing pattern rather than duckwing.