A new mutation...???  

The green colour in parrots is due to the combination of two  factors: the light distorsion giving the blue colour and the yellow family pigments (psittcacin)

In some colour mutation the yellow psittacin can be totally or partially missing.
When it is totally missing the bird will be blue and the mutation is named "blue".
When it is only partially missing the bird will appear more or less blue (or more or less green) regarding to the quantity of psittacin still present, we call them "parblue" and agree  calling it "Turquoise" when it is more blue and "Aqua" when it is more green .
What happens when the loss of psittacin occurs on a non green bird?  For the Cockatiel by example, it can't look blue as it doesn't have any green feather in the wild type. The only place where the loss of psittacin can appear is in the orange cheek patch, giving a "white face" for the "blue" and a "pastel face" for the "parblue".

What about our Bourke's parrot?

The normal wildtype doesn't have real green feather but it has psittacin pigment.
The psittacin is most visible in the Lutino mutation (and of course the Opaline Ino combination).
If the psittacin is  totally missing the bird fits the "Blue" mutation definition although it doesn't look blue.
On the wild type that wouldn't be very obvious.
But when combined with the Ino factor then it would be more obvious, we should get an "Albino" (Blue Ino) and if it is only partially missing then we would have a "ParblueIno" usually named "CreamIno" in the Scarlet chested species.

This year a young Lutino Bourke catched my eye  as it looked really near white besides the other Lutino chicks in the nest. It fledged near white with a very pale pink wash on chest and a pale yellow tinge on the wings. You can see the difference with an usual Lutino sister on the photo. 

Regarding the Scarlet-chested species and after discussing with  geneticists it seems that it could be a "CreamIno" Bourke... (Parblue Ino).
Another Bourke of the same colour apppeared also this year by a Belgian breeder but unfortunately died before I could go and make some photos.

That  colour surely already appeared in other aviaries beeing unidentified as it can look just as a "pale" Lutino!
But, as you can read it, I use the interrogative form in my tittle... because it still needs to be studied and established to be sure about the mutation!.. that will need a lot of time!

Please contact me if you have such Bourkes in your aviaries, so we could try to better understand that mutation.

Two young Lutino Bourkes

Cream Ino?

               A CreamIno Scarlet chested Parrot cock

            and an Albino Scarlet chested Parrot hen.