Coming late to this thread...it seemed like things were drifting into recorded oddities.
It seems like one could do a book on such things. However, for me, finding a definition or some sort of limiting aspect might be difficult. For example:
Piston: Incredible Flutist (calls for a dog to bark)
Kagel: Acustica (gargling and belching)
Geesin & Waters: Music from the Body (just about every sort of human function from farting to heavy breathing)
Wes Harrison: Mr. Sound Effects (Released by Chicago Stereo Mastering in "Stupefying Stereo")
Maxwell: Ebb Tide (sea gulls)
Respighi: Pine of Rome (nightingale)
Hovhaness: And God Created Great Whales (whales)
Rautavaara: Cantus Articus (birds)
Ferrari: Presque rien No.1 (Daybreak on the Beach... all related sounds)
Ralph Platt: The Birds Sing His Praises (...Where the birds of the forest sing to the pipe organ music of Lorin Whitney)
Kodaly: Hary Janos (orchestra imitates a sneeze)
Penderecki: Devils (in the exorcism scene the orchestra imitates a fart)
Takemitsu: Water Music (musique concrete based on the sound of water drops)
and while there are several records of heart beats...both in humans and in dogs...
my favorite record to play after Thanksgiving Dinner....Stahlgren and Ferguson: "The Unruly Guts" Peristaltic sounds in gastrointestinal obstruction: a self-diagnosis tool
Of course there are likely countless easy listening discs with all sorts of sounds from rain to birds and beyond.
Forgive me, but I have forgotten...did I have a point to all of this?