This post concludes the hypothetical discussion of my previous three posts, the first of which you can find here.
By the end of this long thought-exercise it would seem that the most feasible explanation for the barring and display is that the male turacos developed the barring to signal their quality—both to females and other males—not because the barring is expensive to produce, but because the standardized bars allow for close comparison of individuals. By relating directly with growth, bars should allow females to assess the males’ age and relative fitness; they also probably accentuate indicators such as body symmetry, foraging ability, and health. If snake and raptor predators do in fact rely on the ultraviolet pigments to hunt the male turacos, then the barring is probably not only an indicator of (or proxy for) fitness but also an honest handicap that allows males to demonstrate their higher quality (e.g. their low feather wear despite increased need for predator avoidance).
If this were a real discovery, the biggest priority would be to engage in further research that might illuminate the turaco’s relationship with other members of its habitat, as well as the factors that influence a female’s choice of male. Male-male turaco interaction and the differences between adolescent and mature male turacos would also need to be explored to determine the dynamics of bar development and perfection of a sexual display.
Further Reading:
Hasson, Oren. 1991. “Sexual displays as amplifiers: practical examples with an emphasis on feather decorations”. Behavioral Ecology. 2 (3): 189-197.
Zahavi A. 1977. “The cost of honesty (further remarks on the handicap principle)”. Journal of Theoretical Biology. 67 (3): 603-5.
Organikos 
This bird is gorgeous! Great post.
Thanks! There’s a huge wealth of photos and videos here if you’re interested in seeing more: http://ibc.lynxeds.com/family/turacos-musophagidae