Every once in a while, I think back about a bird that I encountered in June/July 2013 in Seewinkel. This female Red-backed Shrike / Neuntöter (Lanius collurio) was paired to a male. Her special feature was this one right outer tail feather, which showed a perfectly male pattern: large white base, with black terminal bar. It seemed like the one or two tail feathers next to it were missing.
I found no explanation or similar cases. Could this be some sort of Gynandomorphism (animals that have part male, part female appearance)? In many bird species, old females tend to exhibit male characters. But this bird didn’t appear old at all, with vivid brown nape (which becomes grey in many older females, some even become very male-like).
