Birds like this are very educative, I now know about wheatear moult. The following is my latest Orkbird post. Posts on here on previous days were also just cut and paste jobs. I did miss out a bit of a disagreement - but it added nothing to the argument.
According to Lewington / Alstrom Desert Wheatear cannot be reliably aged in the field except in early juvenile plumage. So is there any reason (e.g. moult) why our bird couldn't be an adult female? Probably from the pix it may be possible to see..."primaries more worn"; not especially helpful, I thought they looked quite fresh with those neat tips but other opinion would be handy (that would make it an adult)..."a moult contrast can often be seen among the greater coverts" Anyone note anything there? My edition of Svensson doesn't help.
What about the race of our bird? Jonsson mentions three races of which atrogularis of Central Asia is the darkest. Few Scottish records have been assigned to subspecies although Forrester and Andrews suggest that an Eastern origin is most likely for our autumn birds. When I finally signed up to Bird Forum to read the discussion there yesterday there was a suggestion that the rump colour, and therefore maybe the overall colouration, might be caused by reasons other than race, it might be erythritic.