In 2017 I reviewed the first in the two-book set of Peterson reference guides to bird sounds of North America, east then, west in hand today.
I was dubious about using them. On second look, both of these books are helpful to someone like me, a guy with a tin ear. The value of this set extends to birders who have better ears.
Tin ear means an "insensitivity to and inability to appreciate the elements of performed music … the rhythm, elegance, or nuances …"
That's me and bird sounds. I have trouble recreating in my mind what I just heard, how the sound/song was structured, when high, when low.
This pair of books from Houghton Mifflin Harcourt present massive amounts of work by author Nathan Pieplow. He has created thousands of spectrograms of bird sounds.
A spectrogram is a sound made visible. You can see these bird songs and calls.
Plus, there is reference to more than 6,000 bird sound files available online at petersonbirdsounds.com. With the song in my ear and the spectrogram in my eye, suddenly vague sounds take shape and make sense.
Sonograms take some study by the reader/listener. But being able to put sound to diagram is very helpful. I can hear better when I use my eyes.