The Caique Site
|
The Caique Manual
29. Mutants, hybrids and color variants. I have found only one reference to the existence of a variant color form of a caique that might be a mutation. Dr. Smith reported (1990) that a lutino form was imported into England shortly after World War II. He did not state what sub-species it was. Unfortunately, it was kept as a pet and died without leaving any progeny. Thus, caique lovers were denied the opportunity of this form being brought into aviculture. It is inevitable, though that new variants will appear, so it is only a matter of time before some breeder discovers another. I hope this time; the owner keeps it for breeding.
Another method of altering bird color is by diet. This is commonly used to augment the bright reds and pinks of canaries, flamingos, and occasionally that of African gray parrots. This effect on coloration is thought to be harmless, but I have yet to come across a report of this for caiques. It is clear that diet does affect plumage coloration. As noted in the section on diet, I purchased a bird with a pied appearance. This bird had splotchy yellow feathers inter-mixed with the green ones on the bird’s back and wings. As I noted in the section of nutrition, this bird developed normal plumage once I put it on a healthy diet. Cockatiels fed diets deficient in either choline or riboflavin lack melanin in their feathers. These birds develop yellow flight feathers (Grau, 1989). It seems likely a deficiency such as this is what that caused my caique to have the pied appearance. Another way to achieve color variation is by hybridization. Generally, parrot aviculturist frown upon hybridization, and strange as it may seem at least one state, New Jersey, has a law forbidding hybridization. This is not particularly rational, but seems to be a reflection of the view of the aviculturists involved in conservation of species more than those breeding birds for the pet trade. I concur with the view of limiting hybridization at this stage of caique aviculture in order to establish "pure" blood lines. Hybridization is going to occur, and it is difficult to make a rational argument against this when the birds are going to be kept as pets. This is already happening in the case of the green-thighed white-bellies (P. l. leocugaster). There are so few of these in the North America, that breeders have been forced to mate them with yellow-thighed white-bellies (P. l. xanthomeria). Yet these poor harassed breeders have been so castigated, that they are reluctant to disclose that their chicks are hybrids. So, we all lose because of their reluctance to share their knowledge. Thus, our knowledge of the coloration’s to expect in hybrid chicks is nearly non-existent. Dr. Smith promised to publish his findings in this regard (1990), but to my knowledge has not. The only published report is for a single chick resulting from the very first breeding of caiques in captivity. At a time when caiques were nearly unobtainable in England, Lady Poltimore (1930) paired a pallid male (M. m. pallida) with a white-bellied female (P. l. Leucogaster). This pair hatched four chicks of which only one survived. This chick developed plumage the same as the male parent’s except its thighs were green and it had a more salmon color on the back of its neck. In private conversations with persons breeding mixed pairs, the green-thigh trait also seems to be genetically dominant when a green thigh is crossed with a yellow-thigh. Unfortunately, all these reports are for young birds, and we do not know what coloration changes occur as they age. I suspect that many more interbreeding has occurred, but because of the virulence of the avicultural community against hybridization, the coloration of the chicks has gone unreported. This brings us to birds from the wild that do not conform to the accepted descriptions of the different subspecies. The descriptions given in the section above provides only the expected characteristics of each of the subspecies. In Amazonia, their native habitat, there is a variation across their respective ranges. Nearly every author who writes about the distribution of caiques describes their ranges, particularly the observation that the Amazon River sharply separates the black-headed form of the north from the apricot-headed of the south. What they do not tell you is that within the geographic zone, particularly where their ranges are contiguous, the birds inter-breed and produce non-conforming phenotypes (Haffer, 1977). These areas are called clines or clinal belts. For caiques, the greatest variation occurs in the western ranges the different caique species where the Amazon river and its tributaries are not so dauntingly wide. Caiques are not good fliers. Even when their wings are left unclipped, older pet birds usually can only manage to fly a few yards before they drop in exhaustion. This is believed to have kept the white bellied (P. l. leucogaster) south of the river well separated from the black-headed (P. m. melancephala) on its north shore along most of the river’s length. One of Dr. Smith’s male yellow-thighed caiques retained its black-pigmented feet and periorbital skin even after he had owned it for over twenty years. Normally young birds of this sub-specie have gray to blackish feet that slowly become non-pigmented. He also reported that occasionally pallid caiques, which have yellow thighs, develop greenish thighs. I have noticed that among the "green tailed" caiques, there is also considerable variation in the extent of yellow on the tips of the tail feathers. These differences, seen in wild origin birds, demonstrate the difficulties in distinguishing sub-species from one another. (There is a good web page related to color of parrots at Clive Hesford's Genetics of Color web site.)
|
