Sexing Pied Flycatchers during autumn needs a cautious approach since many birds (incl. a few adults) are quite intermediate and variation is marked.
1cy/2cy+: In general, males have darker (jet-black, or nearly so) longer uppertail-coverts and central RR while females show a paler greyish-brown colour. The same difference (but less pronounced) is also visible in the PP. These characters holds true for most adult birds, but in 1cy the individual variation is rich (most birds are intermediates), and only the darkerst/palest birds should be sexed. There are also average differenses in the distribution of white in the outer RR (on average more white in males), but the practical use for ageing is quite low due to the marked individual variation. However, as a basic rule, the black-and-white pattern is often more distinctly set of in males than in females.