Dominant Grey budgerigar mutation

In both the blue and green series birds the flights and long tail feathers are black.

When combined with the Dark mutation the body colour of both Greys and Grey-Greens becomes slightly darker, but the effect is much smaller than the effect of the Dark mutation on Light Greens and Skyblues.

[2][3] In 1936, it was reported [4] that W F Shepherd of Kew, Victoria, also had Greys which he obtained from a colony breeder, and a Grey was also bred independently by R Hancock of Beverley, South Australia, in 1935.

Dominant Greys were first imported to Britain around 1937, one by R Brown of Morecambe for Walter Higham,[3] and one, from R Hancock's stock, by Tom Goodwin.

That is, the presence of a single Dominant Grey allele is sufficient to permit the full expression of the mutation.