Rose opaline Bourke
Development: The opaline mutation was developed in 1972 by Goossens (Holland). I inspected my early notes made after a visit to Schinveld. What I know is that he tried for some years to breed a rose Bourke without results. He tried to find Bourke's with extra rose in the belly. One time he bought a wildtype cock in the neighbourhood. He mated this cock to an isabel hen. He was surprised when he saw two wildtype cocks and two rose hens in the first nest. In the new breeding season he mated brothers and sisters. The results were poor. Only a few young in the nests. And some young died soon. Again in 1973 he got from his first pair two rose hens. In the years after he succeed to was develops a strain. In the beginning the variance in colour was big. The first rose hens had a white bend of the wing. One hen had white stripes on a partly rose wing. Some specimen had a brownish head, rump and tail. Others had dark undulations in a rose breast. Some had brown wings either. After a laborious beginning he was extremely successful later. In 1977 he was breeding 150 youngsters in one season, 45 of them were rose. The first time he thought that the inheritance was recessive, but after he was selling some birds it was absolutely clear that the inheritance was sex-linked.
Description: The red colour is rose under influence of the brown eumelanin left in the back. The opaline factor is a eumelanin mutation. The eumelanin is reduced in several feather fields. The mantle, a part of the secondaries, tertials, greater, middle and lesser wing coverts. The rose opaline is missing the blue frontal band, so determine the sex is more difficult. Also in other feather fields too, the blue is (partly) disappeared. Many specimen are missing blue in the wing and the tail. The blue frontal band becomes white. Selection of hen and cock is difficult.
There are three characteristics of the eumelanin:
1. The fine stripes on the back some dark tips of the contour feathers.
2. A broadening of in the under wing stripe. You see this very well when the bird is flying. When he is perching, a white triangle is visible in the bend wing. 3. the sex linked inheritance.
In the opaline colour variety the red pigment is increased by selection, the red colour is expanded in the plumage and intensified. They were selecting opaline with a minimum eumelanin and a maximum red pigment. Nowadays we see rose opaline but also red opaline, with a nice deep red colour on the back and on the head and chest as well. The red is contrasted by the not bleached outer flights, they are more black than brown.
This is not another mutation but it is a new colour variety.
Mutation factor: The mutation factor is a M-factor. The inheritance is sex-linked. This factor is independent of the psittacine factor and the micro structure factor. The intensification of the red colour and the extension of the red pigment was stimulated by selection. The first specimen had a lot of brown coloured feathers, on the head, the undulation on the breast and the brown structure on the wings.