And if we did keep such a list, who would believe us? :) Have to add:
there are not many of us who can be absolutely sure of an identification by
sound alone. There are some bird songs that one can imitate by pitch if they
are within our singing range: for me, at least, it's the Trumpeter Swan ,the
Black-bellied Plover and American Bittern (am a choir alto.) For others, who
are accomplished musicians, I'm sure that they can identify songs in other
voice ranges. And then there are the extraordinary listeners: have you all
heard the tape by "Big Jake" from Great Britain ? He imitates, with
incredible fidelity, the "whistled" songs of that country's shore birds. And I
have heard other excellent birders identify the "skulkers" beneath bushes and
"flitters" in trees by "chip" sound alone.

So, Tweeters, the question remains: can a "heard" bird be counted on any
list? So glad you asked :)!! Regards,

Murray Hansen
Graham, WA
MurrayH at aol.com