Stephen and Steven, you are the best
Kentuckienne - I'm back and forth on your proposition. Where I fall with a nervous disorder is not likely. The key here is the seasonality of the barbering a devoid disprder would theoretically be capable of manifesting at any time, not just in the winter. Drying of the sheath could be a contributing factor. But I've used many tricks to divert his attention without success. So whether it's just plain fun, or a developed habit from a previous trauma, we are back to square one: he has a habit that likely can't be broken.
I hope I'm not hijacking your thread. It's just that your post came right when I was beginning to research my ideas. You have a better background for thinking about this than I do, so do you mind if I throw out some more questions?
Google offers me up various reports indicating that RLS (restless leg syndrome) might have a seasonal component, with peaks in the summer months:
https://www.ncbi.nlm.nih.gov/pubmed/24152798
And some reports that high or low vitamin D levels may play a part:
https://www.vitamindcouncil.org/vitamin-d-and-restless-leg-syndrome-where-does-the-research-stand/
A report suggesting a connection with RLS and antihistamine use:
https://go.aastweb.org/Resources/PDF/A2Zzz18_2/Histamine.pdf
And various anecdotal reports connecting worsening RLS and wheat consumption.
Looking for a pattern....parrots don't take antihistamines, but histamine levels might fluctuate during the year, being lower in the winter when there are fewer airborne allergens, so if low histamine levels play a part there could be a connection.
The vitamin D info is all over the place, with some studies saying searches for RLS peak in summer, but also research connecting RLS with lower vit D. Could it be that low levels of vitamin D are implicated, but people take antihistamines more in the summer, which overwhelm any vit D correlation?
Some anecdotal evidence claims eliminating wheat from the diet has cured cases of RLS. I'm generally skeptical of these claims, because it's such a fad to be gluten intolerant or whatever, but there are genuine cases of people who produce unusual proteins when consuming certain foods, including wheat, which can affect neurological function.
Other research implicates metabolic processes relating to iron utilization and dopamine levels. I understand that clinically, it's important to differentiate between RLS and neuropathy, and it's not possible to ask the bird about the relevant symptoms.
Most of the studies I found said that RLS does not lesson over time without treatment.
Is it possible to make useful conjectures?
Once a parrot starts plucking or barbering, they tend to keep it up. This could be because it's become a habit, or it could be because of some continuing neurological stimulation/irritation.
Metabolic deficiencies can be idiopathic, but there is often a strong genetic component, some defect in a gene. I'm not aware of any data or study that looks to see if birds that pluck have parents or siblings who pluck, but it could be that a plucker might be sent to a breeder if the owner can't stand to see it. Also, don't some species such as Quakers, greys and cockatoos have a reputation for plucking? Plucking can begin in any parrot, but there could be more than one cause. I have a relative with E-D hypermobility syndrome, and there are multiple genes involved in the different flavors of E-D. Some require both parents to have the gene, some only one.
I read that RLS also improves with activity and stimulation. Parrots also do better with more activity and stimulation, and sometimes this alone is sufficient but not always. I am sure Parker does not lack for attention or toys.
One thing that bothers me is that parrots don't seem to display this behavior in the wild. It seems that if it were purely biochemical or genetic, it would appear at least some of the time. Does it only affect captive birds? Does it only affect birds that are kept indoors out of unfiltered natural light? Is the syndrome more prevalent in captive bred birds than in wild caught birds? Is there some infectious vector circulating through the captive population? I could see that...birds come from breeders or pet stores, share cages, humans could carry bacteria or viruses in from outside. Maybe it's a Typhoid Mary kind of thing, where some or even the majority of birds can tolerate it without problem?
Anansi, this is like what you wrote a while back, about a neurological basis for toe-tapping and feather disorders. It's not a far stretch from toe-tapping to RLS. And if a feather disorder can be linked to toe-tapping, it's not a stretch to connect plucking. I don't know of any research, it's pure speculation. It can be difficult for a lay person to find good research. I know that I can wade through pages of crap and then find a good scholarly paper on like page ten of search results.
If the problem has become a habit, even habits can be changed. Say there's a threshold, where with a combination of biological and environmental triggers the plucking behavior starts. If the biological contributors can be ameliorated, is it possible that sufficient environmental changes could push the bird back over the threshold, say instill a different habit that isn't compatible with plucking so the bird can't do both at the same time? What kind of new habit might that be?
Are there any things worth trying? Change the diet to remove wheat or other non-native elements? Don't some birds get vitamin D by grooming their feathers, so if they have fewer feathers they'd get less D, vicious cycle? Do vets check vitamin D levels or know what is optimum? Are there any histamine increasing foods or dopamine increasing foods?
There has got to be a solution for this syndrome. It's just that parrot owners aren't usually scientists and most scientists are probably not parrot owners. But there is enough overlap. Is it a matter of funding? Are any veterinary universities doing research?
