Abstract
The Bourke Parakeet still remains a very popular bird in our aviaries. It's colors may not rival those of many other parrots but the soft shades of blue, brown and red are indeed very attractive. The males in particular are very showy specimens. Like other grass parakeets, the Bourke is a quiet and gentle bird, never destroying any part of your aviary. It is also a very friendly and relaxed bird often acting more like birds which have been hand raised. All Bourkes become very active when darkness approaches and they may still be feeding on the aviary floors when other birds have already retired for the night.
One other reason for the Bourke's continued popularity is the emergence of several attractive mutations. Mr. R. Smith has already reported on the Yellow Bourke (AFA Watchbird, Apr. - May, 1977) and Erhart elaborated on the differences between the genetic inheritance of the sexlinked Cinnamon and the recessive-breeding Yellow Bourke (AFA Watch bird, Oct. - Nov., 1977).
One of the newest mutations is the stunningly beautiful Rosy Bourke. Most color photos can't do justice to the soft rosy reds which cover almost the entire body. Only the tail, the primaries, and a few of the secondary wing feathers remain dark. Some blue remains on the rump and on the secondaries, but the blue frontal band on males as well as the intense blue of the underside of wings are missing.
The first Rosy Bourkes appeared in the Dutch aviaries of Mr. Goosens in 1970 and 1971. He had paired a newly acquired normal male with a hen which originated from his cinnamon stock. This pair produced four normal looking males and three hens which were covered with rosy feathers over their entire back. These offsprings formed the nucleus of a beautiful new mutation: the Rosy Bourke.
The genetic inheritance of the Rosy Bourke became the subject of great controversy among European aviculturists. For years they were thought to be a recessive mutation and males and females were sold as splits. Prices averaged about $1,900 for the Rosies and nearly$1,500 for the splits. In 1977 the German aviculturist and well known breeder of mutations, Siegfried Bischoff, suggested that the Rosy Bourke is really a cinnamon mutation in which the yellow pigments are replaced by reddish pigments. Such a mutation should, of course, be sex-linked. His idea proved to be correct, and it is now generally accepted that the Rosy Bourke represents a sex-linked mutation.
Though my own breeding results have substantiated the sex-linked nature of this mutation I should add that the Rosy Bourke also exhibits pied-like characteristics, i.e., no one Rosy Bourke looks quite like any other one. Some are nearly entirely rosy, still others show a substantial amount of melanin pigments. Eventually, I am sure, we will be able through selective breeding, to produce an all red or rosy-red Bourke.
Breeding the Rosy Bourke produces few surprises if we recall the laws of sexlinked inheritance. Therefore, a normal split-for-rosy male paired with a normal hen will produce 25% Rosy offspring, all of which will be female. Another 250Jo will be normal females and the remaining males will divide up evenly into normal males as well as split Rosy males. Only test breeding will tell us which males are truly split.
Crossing a split Rosy male with a Rosy hen will produce 50% Rosies of both sexes. The other 500Jo will also consist of males and females but only the males will be split.
Finally, a pairing of a male Rosy Bourke with a normal hen will produce 500Jo Rosy Bourke hens and 500Jo split Rosy males. This is obviously a very desirable combination. Rosy paired to Rosy will produce...