Yet once it calls or sings it is instantly identifiable - if you know its calls. Its call is a rough sputtering pair of notes, not easily rendered phonetically. What's important is not that we agree on how to spell these sounds but rather, that we can look at these words and are able to recreate the calls in our mind. That is why you need to write down your own renditions, as you hear it, and not rely on what others write. These phonetic renderings aren't the only way to record bird calls.
Sonograms are computer graphs of bird songs with frequency on one axis and time on the other.
Many people find these useful. But like sheet music, I personally can only get a vague idea of the sounds by looking at a sonogram. Its horizontal length represents the period of time the note occupies. Its vertical height, in relation to the other notes in the song, represents the note's pitch. Its heaviness represents its loudness or intensity.