Sometimes Eclectus show unusual feather coloration, or show a red feather where green feathers should be or vice-versa. Sometimes only one or two feathers are involved, but in other cases, many feathers are involved. Caregivers who notice unusually colored feathers on an Eclectus parrot usually find that a diet that excludes artificial colors, supplements, additives and added vitamins results in normally colored feathers at the next molt. A visit to an avian veterinarian is recommended by experts to exclude or identify possible diseases that may be causing the unusual feather coloration, especially if more than a few feathers are involved.
I am not an expert, but I have read extensively about the reasons that unusually colored feathers might occur in otherwise healthy Eclectus (i.e., odd coloration notcaused by liver or other disease, or medications, etc). I will touch on a few of them, starting with one that is least likely.
Some odd coloration might be due to a type of mosaicism where there may have been a chromosome cross-over, or situations where some cells actually are male or female versus the rest of the cells of the body. In these scenarios, the color of the feathers where these cells occur would be permanent. Increased numbers of such cells might cause what is commonly referred to as a "half-sider" or when there are both male and female cells, a "gynandromorph", including a bi-lateral gynandromorph (or the "embryo chimera" that Roger Sweeney refers to in his Eclectus book). This is a rare occurrence.
There seem to be a few bloodlines of Eclectus that have a particular color trait, such as the red "cravat" on some males. The cravat refers to a few red colored feathers around the neck or on the breast in such a way that it may remind one of a tie, cravat, scarf or necklace. It appears that at least some males pass this cravat marking (in varying degrees) on to their sons. I have not read that they also pass it on to their daughters (such that the daughters produce sons with the cravat), but they may. The cravat often does not molt out and is a permanent, genetic color trait.
Some of us think there may be other reasons for these unusually colored feathers, particularly in cases where the feathers later molt into normally colored plumage. Of course, these ideas must be tested, so for now, they are only conjecture.
I have read that the plumage coloration of Eclectus parrots may be influenced by hormones, and may be dependent on female sex hormones such as estrogen. It may be that there are pigment- producing or transferring cells or structures associated with the feather follicle (perhaps similar to those for melanin). These may be able to color feathers of either male or female pigmentation, depending on the hormonal or chemical signals received. If this is true, when a hormone like estrogen is present or present above certain levels, female plumage pigmentation results. Likewise, if estrogen levels are below the threshold, male plumage pigmentation results.
NOTE: Thanks to Dr. Alan Brush for pointing out that hormones do
not "directly control the pigment. The pigment is produced somewhere in the
body, probably modified from a precursor. The hormone can effect
1) the synthesis of the pigment
2) its method of transportation in the body and
3) how it is taken up by the follicle
Hormones are necessary, but -by themselves- not sufficient. There are several more steps."
If these theoretical pigment producing structures are damaged (perhaps by continual feather picking), or if they receive incorrect hormone or other chemical signals during all or part of the time during which they are producing/laying color into the feather, the feather may not have the correct color. If the signals are received sporadically, it may explain why some feathers are colored in scalloped, rainbowed, or ribboned patterns of color, or even strange colors (this does not include normal mixed color, such as the feathers of the border of side patches on male Eclectus). Other feathers that were forming at the same time may show similar unusual color.
Other substances may also be
involved, such as in the process of signaling the pigment cells, in creating the
pigment, or in creating the structure of the feather itself. For example, blue
is a structural color. If something should affect the formation of the
structure of the feather that creates blue, then green feathers could be
affected (because green color is a combination of structural blue and of yellow
pigment). If structural blue did not form in a normally green feather, the
result might be a yellow feather. So you can see how diet (even medications and
vitamins and other supplements) could play a very important role as
well.
In this scenario, if the factor(s) that caused the unusual
pigmentation are "normalized" prior to those feathers forming for the next molt,
then feathers that form during subsequent molts would be normally pigmented.
This seems to happen in many (or even most) cases, based on the observations of
Eclectus owners. For this reason, in my opinion, it is important to ensure that
a healthy juvenile Eclectus with unusual feather color has had a chance to
undergo one or even two molts, and that all healthy Eclectus showing unusual
feather pigmentation are placed on a good diet that does not include artificial
vitamins and supplements, and allowed to undergo at least one complete molt
after the diet change before considering that the Eclectus may be a
mutation or have permanent unusual feather coloration.
Interestingly, research indicates that some areas of feathers of at least some kinds of birds are more affected by signals (such as hormones) than others. So it may be that feathers of certain areas may have unusual pigmentation while feathers of other areas are unaffected, even though they formed at the same time under the same circumstances.
I look forward to the day that more is understood about this very fascinating subject. I will enjoy updating this page as I learn more. If anyone is interested in the references that I have consulted in regard to these thoughts, please let me know.
Mary Nogare