thanks! after i found out what colour turqoise was (lol) i looked and yeah his tail is that colour and goes really dark at the end although arent all blue budgies like that? i also did a bit of research and have decided that he is probably violet sky blue.From what I can see of his tail feathers he may be a Violet Sky. In a Violet Sky the tail feathers are Turquoise and the base of the tail going down to very dark navy.
um what is suffusion?No the Sky Blue is Mid Blue with Turquoise suffusion where the Violet Sky they are quite turquoise at the base of the tail going down to dark blue. It is quite different to a normal sky. Olive budgies also have blue black tail feathers and violet cheek patches unlike Grey Green Budgies that have black tail feathers and the cheek patches are a blue grey. That is the only way you can tell a true olive from a grey green. It seems to be something to do with the violet gene.
This is from the Standard of the Budgerigar Society of NSW and also covers all of Australia.
Colour Cheek Patch Tail Quill Tail Feather
LIGHT GREEN Violet Black Mid Blue with Turquoise suffusion
DARK GREEN Violet Black Dark Blue
OLIVE Violet Black Dull Blue-Black
GREY GREEN Grey Black Black
SKY BLUE Violet Black Mid Blue with Turquoise suffusion
COBALT Violet Black Dark Blue
MAUVE Violet Black Very Dark Blue with Black Sheen
VIOLET Violet Black Deep Royal Blue
GREY Grey Black Black