I had an extended opportunity to observe two male elisae today. Hsiao 2017 says that the bird is “silent outside breeding period”. I observed extensive vocalisation from one migrant bird today; intermittent, frequent singing with occasional calls. Brazil 2009 say that “song awaits transcription” and goes on to describe 3 types of calls, one a sharp “tek tek”. I head this sharp calls and an edited call recording is found here: https://www.xeno-canto.org/456681. It is a sharp call that occurs 2-6 times (often 5-6 times), lasting 0.5-0.6 seconds. The bird did not look distressed but these calls were in sharp contrast to the majority of songs I heard.
The songs I heard today were long and rambling, going up and down in intensity – like a warble. In general they were not easy to hear against the background of loud insect hum of the jungle. The bird would lift the head and beak up, the throat would get full. Occasionally, during calls, the beak did not open. An edited call recording is found here: https://www.xeno-canto.org/456686 (some odd noise at the beginning). Lu Dong and colleagues describe the song of elisae as “soft and clear, though a slightly harsh warble with more variation in frequency, consisting of usually long phrases separated by short pauses”. Pretty much what I heard for much of the morning today.
Taxonomic Notes :
The subspecies elisae is sometimes treated as a separate species Green-backed Flycatcher Ficedula (n.) elisae. However, a recent study recommends retaining it as a subspecies of F. narcissina: Töpfer, T. Systematic notes on Asian birds. 60. Remarks on the systematic position of Ficedula elisae (Weigold, 1922).
Zool. Med. Leiden 80-5 (12), 21.xii.2006. 203-212.— ISSN 0024-0672.
Note that "Ficedula beijingnica", which was at one time regarded as a separate species called Beijing (or Peking) Flycatcher, is now considered to be the first-summer male of F. (n.) elisae and no longer a valid independent taxon.
The subspecies owstoni is sometimes treated as a separate species Ryukyu Flycatcher Ficedula (n.) owstoni.