Identification
In all plumages the yellow rump is distinctive. The white supercilium of the male is distinctive, separating it from the Narcissus Flycatcher and the Chinese Flycatcher. Females and first year males are olive grey above with blackish tail. Hartert (1910) treated this as a part of the narcissina group. Some individuals with yellow supercilium have been considered as hybrids with the Narcissus Flycatcher. Included in this species complex was the species called Elise's Flycatcher, usually treated as a subspecies of the Narcissus Flycatcher. Both elisae and zanthopygia have been observed to breed separately in the same area of oak forest near Peking strengthening the case for their distinctness. There are also clear call and morphological difference between the two. The genus Muscicapa has been noted to have been polyphyletic and is still in the process of being resolved although the genus Ficedula is now considered monophyletic with their origins in east Asia, with diversification following climate changes in the Pliocene.
Read more about this topic: Yellow-rumped Flycatcher