Abstract
Derbyans are one of the larger members of the Psittacula family and are natives of the coniferous forests in the People's Republic of China. They are inhabitants of the mountainous areas of the Himalayas and tolerate the cold better than most of the other members of their genus.
The coloration of the Derbyan parakeet is both subtle and striking. The entire breast is a beautiful dusty lilac; a color rarely seen in birds. The breast color of the adult female tends to be slightly pinker in comparison to the male. The majority of the body is a deep emerald green. The wings are also emerald green and are adorned with a large yellow-green patch. The central tail feathers are long and graceful, comprising one-half of the overall length of the bird. They are a deep cobalt blue on the dorsal side.
The feet are dark grey to black as are the legs. The upper part of the legs is covered with lilac colored feathers that look somewhat like bloomers. Both adult males and females have irridescent blue-green feathers on the crown and cheeks lending a jewellike quality to their appearance.
We have observed that the blue irridescence tends to be heavier on the faces of the hens; a characteristic noted in Moustache (P. alexandri sp.) hens as well.
Heavy, black, moustache-shaped markings traverse the lower cheeks and neck on both male and female Derbyans. Each has a heavy, black "eyebrow" marking just above the upper mandible. These markings appear with the first feathering of the baby Derbyans (also in Moustache species) rather than being molted in at one year of age. This early facial coloration or marking is a peculiarity of those members of the Psittacula genus that display dimorphic bill coloration in adulthood. Also peculiar to only those Psittacula with dimorphic bills is the fact that they molt into adult plumage at 13 months, whereas the rest of the genus reaches adult coloration at 27 months, although some domestic Indian Ringnecks are coloring up even sooner.
Derbyans are, indeed, dimorphic as adults, i.e. you can tell the difference between the sexes visually. The males are easily distinguished from the hens by their coral red bills which are tipped in yellow. Both the upper and lower mandibles are black on the hens. All baby Derbyans hatch with a pale orange colored bill, which darkens considerably over a period of a few weeks to a deep orange. After the young birds are fully feathered out, their bills have turned to black. At approximately 13 months, the young males begin their adult molt and the bill begins to change back to coral red. The hens, too, go through an adult molt, but their bill remains black. With each successive year's molt, the coloration of the feathers intensifies, and the central tail feathers of the male birds grow slightly longer each year. Fertility in Derbyan males was thought to occur at 27 months. At this time, we haven't found any hard evidence to prove or disprove this theory. We have, instead, found that all of our domestically raised Psittacula males, including the Derbyans, are fertile at two years (second breeding season after hatch). The exact age of fertility in the hens is considerably more difficult to judge. However, the size and shell quality of our two-year-old hens tends to vary. The younger hens also tend to lay more eggs per clutch, but the fertility and hatch rates aren't as good as with older hens.
Visually, the Derbyan is about twice the size of an Indian Ringneck parakeet, and roughly the same size as an Alexandrine parakeet. The huge bill of the largest Alexandrine male (Psittacula e. magnirostris) makes them appear to be larger than the Derbyan, even so, the body weight and strength of the Derbyan is noticeably greater. This fact isn't immediately obvious until you have the opportunity (or maybe the necessity) to physically handle these birds.
Derbyans are quite a handful!
Until fairly recent times, Derbyans were extremely rare in captivity. Only a handful of aviculturists and zoos worldwide were fortunate enough to keep and breed this fantastic bird. The few birds that were the original breeding stock in the United States were beginning to show the difficulties associated with a limited gene pool during the latter part of the 1970s. Primiarly, these problems are decreasing production rates and smaller body size.
During President Nixon's term of office, diplomatic relations and trade agreements were begun between the People's Republic of China and the United States. Several pairs of Derbyan parakeets were sent to the United States as part of the cultural exchange.
Since the early 1980s, there have been a number of Derbyans available through quarantine. The infusion of new bloodlines is improving the established flocks tremendously. The increased numbers of available birds is helping to ensure that there will be a self-sustaining captive population. Production rates are much improved and breeders are able to provide larger, healthier birds to other breeders now.
We purchased our first pair of Derbyans in 1979. These particular birds were part of one of the first groups to come into the U.S.A. They were a mature, robust and beautiful pair. We counted ourselves among the fortunate!
These birds were placed in an aviary where we could observe them from our kitchen window. The breeding season came and we waited and watched. The male Derbyan courted and displayed for his hen. They mated numerous times all day long. That kitchen window garnered more viewing time than our television set! The mating rituals went on for several days at a time. There would be a rest period of several days to a couple of weeks, and then the male would begin displayin again. This continued throughout the summer months and into early fall (lune through September).
It was three long years before our Derbyans finally decided to go to nest, and the patient waiting paid off. We have been rewarded by this pair of birds each season with two clutches of babies per year!