Green-backed Flycatcher

The green-backed flycatcher is an Old World flycatcher long treated as a subspecies of the narcissus flycatcher, but morphological and acoustic differences show the two are separate species. It breeds in north-eastern China and winters in south-east Asia. A form proposed as the Beijing or Peking flycatcher is now considered by experts to be the first-summer male of this species. (Wikipedia, general species account)