Comparing the Rubino and the Edged Bourke's variety
1. I made this picture to compare the differences and similarities of two varieties of the Bourke's parrot, the Edged (L) and the Rubino (R) , in paricular the eumelanin pigment and the psittacine pigments. The Edged is a combination of the Edged and the rose Opaline variety. The Rubino is a combination of the Lutino and the rose opaline variety.
The first global impression is that there is great similarity between this varieties. The intensity of the yellow and red colour and the division of the red and yellow pigments in the plumage is almost equal. The global difference between this varieties is the presence of some eumelanin pigment in the Edged and the lacking of this pigment in the Rubino variety.
2. The eumelanin pigment in this Edged cock is found in the crown, cheeks and tips of the wing feathers. The colour of beak and nails is grey. The eyes are dark. The remnant amount of eumelanin in the Edged variety is variable. The main characteristic of the Edged variety where most of the eumelanin is gone, are the dark tips of the wing feathers. The main characteristic of specimen where a small amount of melanin is lost are wing feathers with grey striping. This striping is caused by eumelanin in the shaft of the feather and around the shaft in the centre of the feather. On the picture, the psittacine pigment are dominating in the colouring of the plumage. There is a lot of yellow and red pigment. The transition of red in yellow is not sharp. In the red upper back we see yellow feathers also. In the yellow tail coverts we see red feathers. Compared with the original division of pigments in the wild-type Bourke we see an extension of the psittacine pigments in the back, rump and tail.
3. The rubino hen has no eumelanin in the plumage and horny parts. The beak is horn coloured, the nails are white. The eyes are red. The wing and tail feathers have no eumelanin. The tail has some red pigment. There is a yellow band of wing coverts. When we compare the distribution of the psittacine pigments of the Rubino variety with the Edged variety above, we see that the colouring of the head is different. The red pigment is not mixed with brown pigment. Also the primaries are different. They are white. The red and yellow colours on the back have the same intensity in both varieties. Compared with the Edged cock the Rubino hen there is more red on the cheeks and the tail and lower back. There is a same division of red and yellow pigment. Here is an extension of the red and yellow pigment in the back, rump and tail when we compare with the original wild-type Bourke's parrot.
4. This is a head study of the head of the Edged variety. Remarkable is here the missing of the blue frontal band and the fine blue stripes above the eyes.
5. This is a head study of the rubino hen. The crown has red pigment. The forehead band, throat and cheeks are white. We find this is many rubino's.There is no trace of melanin left in this plumage.
Conclusion: This two varieties have much in common. Both have about the same proportion of red and yellow pigment in the plumage. The differences are the remnant of eumelanin in the Edged variety and the total loss of eumelanin in plumage and horny parts in the Rubino variety..
Question: Is the extension of the psittacine pigments due to the melanin distribution factor of the opaline variety? The answer is no! The Opaline variety came into being years years after the first Edged variety. The Edged Bourke ( in Dutch: gezoomde Bourke) is born in 1967 in the aviary of Beurskens (Holland) and is developed by this breeder. The red and yellow pigment were already distributed in the whole plumage. I made pictures of the first Edged Bourke, who was born in 1967. This cock had a yellow back mixed with red feathers. I bought from Beurskens also a yellow hen, who was yellow in the whole upper and lower back and rump. The tail was silver grey. This hen was born from the same grand parents. We have to find the the extension of the psittacine pigments not in the opaline but else were.
The extension of psittacine pigments started much earlier. The first mutation of the Bourke was in 1957. The yellow pastel Bourke came into being. The breeder was Mr. J van den Brink in Barneveld (Holland) He developed this variety. In the following years a lot of breeders in Holland tried to breed specimen of this variety so yellow as possible. Selection is good possibility by psittacine pigments.
The opaline variety came into being in the aviaries of Goossens (Holland) in 1972, fifteen years after the pastel mutation. Goossens told me personally that he was busy for many years to breed a Bourke as red as possible, before the mutation did happen in hiss strain of Bourkes. The conclusion is that the opaline mutation factor is only influencing the eumelanin distribution. Selection in many years is the reason for the extension of the psittacine pigments in the back, the rump, wings and tail.
By mating the rose Opaline more red pigment is brought into the plumage of the Edged and the Lutino. The influence of the melanine mutation factors is small. In the Rubino is this influence not visible. In the Edged the influence is visible in the disappearance of the blue frontal band.
Conclusion: The extension of the psittacine pigment was increased by selection by an early development and was completed long before the Edged and the Opaline varieties came into being. .The influence of the rose Opaline variety in combination with Lutino or Edged varieties is a change in the proportion of the red and yellow pigment in the plumage. The loss of eumelanin in the Edged, Opaline and Rubino varieties made the psittacine pigments better visible.
Copyright 2005 by Bob Fregeres