Breeding Yellow Mutation Parrotlets

Among the most intriguing members of the parrot family are the parrotlets (Forpus sp.). Physically, they look like incredibly small versions of the Amazon parrots. Average length is only about 12.5cm. Aviculturally, they can be quite rewarding, especially if one has the opportunity to work with some of the new mutations that are being established.

While mutations of the Pacific parrotlet have been under development in Europe for several years, the first Pacific parrotlet (Forpus coelestis) mutation to occur in the U.S. is known as the American Yellow. This dark-eyed mutation is similar to the European Yellow that is pictured on some of the popular species posters (not to be confused with the red-eyed Lutino). The American Yellow however is a much more attractive bird. It is a brighter, clearer yellow, without any dark markings on its wings, making it a stand-out beauty next to its European "cousin."

Both of these yellow forms are recessive mutations. For a recessive mutation to be expressed, a copy of the same recessive gene from both parents must be inherited by the offspring. This offspring would be called a "visual." In the case of the American Yellow, the visual offspring would be yellow instead of the normal green. If only one copy of the gene is passed on to the offspring, the trait would not be expressed visually. The resulting offspring would be normal in appearance but still be a genetic carrier of the color mutation. This would be referred to as being "split" for the visual mutation. This can happen when only one parent is carrying the recessive gene or when the offspring only inherits the gene from one of the two parents although they both carry it. Split birds are capable of producing visual offspring only if mated to another bird carrying the mutation gene. The mate may be either visual or split.

The first American Yellow Pacific parrotlets occurred in a Midwestern aviary in 1989, the offspring of normal colored parents. These first yellows were acquired by an aviculturist well experienced in color mutations in other species. His early efforts included several generations of linebreeding and inbreeding. These methods of breeding were necessary to insure establishing the mutation. Linebreeding is the repeated breeding of mother to son or father to daughter, inbreeding is the breeding of known relatives. Both methods carry the risk of magnifying any genetic weaknesses or faults exist in the line. However, when a new mutation appears, the most critical goal of a responsible breeder is to produce a sufficient quantity of visual birds as quickly as possible so that unexpected mortality does not wipe out the line.

Once there are enough specimens of the visual mutation in existence, you can then work toward firmly establishing the line by outcrossing to unrelated normal colored stock. In choosing normal birds to breed with the mutations, only the best representatives of the species should be selected. Factors that should be considered are size, hardiness, productivity and disease resistance. In many cases where aviculturists have been unsuccessful at breeding the yellow mutation, the problem may be the continued inbreeding of already severely inbred stock. Many breeders will attempt to recoup their investment quickly by pairing these overly inbred visual birds so they immediately produce more of the highly valuable visuals. Rather than achieve their goal, the result is usually the production of infertile eggs or weak hatchlings that do not survive. If these highly inbred birds are outcrossed to strong, normal stock, the results are often much different. While it takes longer to produce offspring that visually exhibit the mutation, outcrossing these inbred birds to strong, normal stock will produce superior offspring.

I acquired my first pair of yellow Pacific parrotlets in early 1994. Due to the close relatedness of this pair (uncle and niece), and the fact that they were the result of repeated inbreeding, I worried about genetics first and my investment second. After a lengthy quarantine, the pair was separated. The young female was placed with normal colored juveniles until she reached maturity. The young male, just barely three months old, was paired with a mature, imported normal hen. This pairing would result in offspring that would be "split" for the yellow mutation. At eight months old, he and his mate produced six strong, healthy chicks that were pulled for handfeeding at about 10 days of age. He was paired twice more with other mature hens, and before he was two years old had produced a total of 25 offspring, all of which were genetically split for yellow. During this time I also traded several of my split birds with another breeder who was also working with the same mutation. This gave me six different outcrossed bloodlines of birds to work with that were split for the yellow mutation. I then set up several pairs of these half siblings and cousins that have since begun to produce yellow babies. In turn, several of these second generation yellow babies have been paired up with one of the other line of splits, or again outcrossed to unrelated normal stock. To date, all yellows produced have been either as large as, or larger than their parents, and certainly larger than the original yellow male. Fertility and production among these splits and outcrossed yellow birds has been consistent with that of genetically typical birds.

At maturity, the yellow female was paired up with a normal male. Although they quickly bonded and mating was observed, no eggs were ever produced. She would settle into the nestbox, her abdomen would swell, droppings would increase in size, all indications that an egg would be imminent. Rather than lay an egg, the swollen abdomen contained fluid and the hen became congested, wheezy, and generally in poor condition. At the completion of these false breeding cycles, she recovered without any intervention or treatment. Over a period of 18 months, she experienced five of these false breeding cycles. She was removed from my breeding program and due to her gentle nature, is now a "nanny" for the newly weaned youngsters. I am constantly reminded how valuable the decision was not to pair the two yellows together in order to "immediately" produce more yellows. Had I not decided to concentrate on improving and strengthening the line, I might still be waiting to produce my first visual.

During the summer of 1995 I was fortunate enough to locate and purchase another young yellow male. This yellow mutation is believed to have occurred spontaneously. Not only did it appear in a different part of the country, but it was also not in any way traceable to the original yellow line. It was identical in coloration to the American Yellows that I had been working to establish. This male was bred to a mature normal female and produced a clutch. Of the four young produced, the two females feathered out with a considerable amount of yellow ticking on the nape of the neck. One of the split male offspring, upon molting, is showing some yellow feathers on his chest and abdomen. Only time will tell whether this will lead to another color variant.

My advice to aviculturists wishing to begin breeding these beautiful little jewels is to purchase young birds. This allows ample time for them to settle in and mature under your supervision. It is wise to be skeptical of "proven pairs" being offered for sale. You may wind up with birds that have been culled by another breeder due to poor breeding habits or infertility. With proper management, one visual color mutation can be the foundation for an entire genetic line which can produce an endless number of specimens of the new color variation. Once this goal is reached, the new beautiful American Yellow Pacific Parrotlet will be available for everyone to enjoy. Until then, they are something that only the serious aviculturist should consider.