Okay... Thanks, Bobbywhy, for those references.
I don't completely understand what is going on, but... I'm going to clarify my stance (hopefully, along the right lines).
First, I think drabness is lack of decoration such as jewelry; relatively monochrome clothing; and subdued colors, such as gray, brown, black. In essence, what people mean when they refer to drab females in birds.
Second, I don't think my question was... Wait. Also, I didn't invent the question. It was posed similarly in the book. Also also, I may or may not have realized that my view of Islamic cultures was a stereotype.
Now, second. I don't think my question involves fashion. Or, rather, it's about either culture-wide trends (if there are such; but great difersity may be a trend in itself), or wide-spread tradition. Which I take to be less about an individual's choice and more about genetics... or subconscious... or memetics... Okay. So, when I put it like this, it seems to pertain more to history than to biology. But it's not my fault!
Third, I'm not a scientist, so I'm very bad (as in, I wrote my graduation paper entirely off Wikipedia) at references to peer-reviewed journal articles.:shy: