FAQ: Are slaty and misty the same mutation and / or are they a grey mutant?
The answer is actually simple: absolutely not.
For a layman, they look maybe similar from a distance, but if you look a little closer you will notice some differences. For example, the slaty factor will result in a grey rump colour, misty does not affect the rump colour. Slaty blue is rather, as the name implies, a slate blue colour, misty blue is blue with a brown shade.
Some breeders suggest that slaty and misty are a grey factor, but believe me it is not.
For the autosomal dominant grey mutation we always take the grey budgerigar as a reference. Both mutants were compared by Inte Onsman at the time. He was formal that they are completely different. Research later with more sophisticated methods (electron microscope and X-ray diffraction) also showed clear differences.
Why this confusion?
We must realize that many ‘grey’ or grey green phenotypes are possible in birds. Autosomal recessive grey, autosomal dominant grey, slaty, slate, dark factor, misty … they all have a greyish phenotype, but the cause is always different. The reason for this is quite simple: any (minor) change in the feather structure / composition of the keratin layer / available pigments or pigments that hinders the normal interference in the sponge zone etc… will almost always results in a more (darker) olive green- grey green / greyish colour.
Believe me, feathers are a very complex matter. There are many colours, but there are also many different causes. A recent example is the autosomal recessive grey mutant in Agapornis roseicollis. We compared feathers of the AR grey Agapornis roseicollis with the feathers of the AR grey Forpus coelstis and even they are not entirely identical.
So for those who think it is a simple matter and these mutations can easy be explained I would like to quote from “The evolutionary origin and diversification of feathers” written by Professor and Head Curator of Vertebrate Zoology at the Peabody Museum of Natural History at Yale University Richard O. Prum: “Feathers are the most complex integumentary appendages found in vertebrates”.
Who are we to doubt it?