Opaline Budgerigar mutation

The Opaline budgerigar mutation is one of approximately 30 mutations affecting the colour or appearance of budgerigars. It is the underlying mutation of the Opaline variety. When combined with the Yellowface II and Clearwing mutations the Rainbow variety is produced.

Appearance

The Opaline mutation is characterised by several features which are invariably present, although many show variations in the intensity of their expression. The most obvious effect is on the striations which extend from the top of the head down the neck to between the wings in the non-Opaline. In the Opaline these striations are very much reduced in intensity, being almost absent in many individuals, particularly in small birds of yellow (as opposed to buff) feather. The cap of the Opaline extends further back over the top of the head, gradually merging into an area the same colour as the body which continues down the back of the head to form a 'V' shape between the wings. The intensity of the striations in this area is variable, but in the original mutations, particularly the Australian, the 'V' was very clear.

In the non-Opaline the wings show dark grey or black markings over a yellow or white ground, but in the Opaline the ends of the barbs of the wing coverts assume the same colour as the body, rather than the ground colour. This suffusion of body colour in the wings produces the opalescent effect which gave the mustation its name. The area of black pigmentation in each feather is reduced and in the original specimens the wing butts were particularly devoid of black pigment, resulting in a clear area often called the 'thumb-print'. These thumb-prints appear to be associated with a clear 'V', but are now seen less often, since the Budgerigar Standard calls for normal wing markings in the Opaline.

The flight feathers of the budgerigar consist of 10 primaries and 10 secondaries. These are dark grey with a clear central band across every feather from the 2nd primary to the 8th secondary. These clear areas are not visible in the folded wing, but form a prominent continuous band running right along the wing when it is stretched out. It is hidden from above by the coverts but is visible from beneath. In the Opaline this clear band is present on every flight feather and is much broader. Only the distal half of the flight feather is dark, with the clear zone extending from the mid-point to the shaft. Because it is broader it is visible in the primaries of the folded wing of the Opaline, just beneath the secondaries and primary wing coverts, as a small clear patch.

A similar effect occurs in all the wing feathers, most noticeably in the primary and secondary wing coverts, and also in the six tail feathers, which carry a similar clear band on feathers 2 to 6 in the non-Opaline. The first (longest) tail feather of the Opaline also carries a rather blotchy clear area of somewhat variable extent, and the suffusion of body colour present to a small degree in the non-Opaline is intensified in the Opaline.

Most Opalines show a brighter body colour than the corresponding non-Opaline, paricularly in nest feather and particularly in the rump area. This is due to a reduction in the melanin content of the barbules of the contour feathers.

The final characteristic of the Opaline (and the Cinnamon) is the colour of the down feathers of the young nestling. These are white instead of the usual grey, and this allows Opalines to be identified at a very early age.