Subsong is the first audible stage of song development in passerines. Often heard from first-year birds or other individuals with little sexual motivation in late summer and fall. Subsong has a low volume and can hardly be recognized as a vocalization of this particular species – it’s sound is so different, unstructured and unfinished, recalling the babbling of a baby.
Below is the recording of a juvenile (apparently male) Citril Finch / Zitronenzeisig (Carduelis citrinella) singing subsong with just a few weeks of age. The bird still had down on it’s head (see photo) and was being fed by its parents. While waiting on a dead larch tree for them to return, it started singing subsong for many minutes, almost without pauses but only rarely opening its bill while singing.
Recorded on a very warm and sunny 6th July 2021 at Dobratsch, Kärnten (1900 m altitude). Equipment: Samsung S10e mobile phone and Rode VideoMic Pro+ on RecForge II app.
Read about subsong and the different stages of song development here.