First birds made honking sounds more than 66 million years ago | New Scientist
Realistic three-dimensional avian vocal tract model demonstrates how shape affects sound filtering (Passer domesticus) | Journal of The Royal Society Interface
The evolution of stem-bird vocalization – Those with Pycnofibres
Secret of the songbirds: How nightingales, skylarks, robins and other birds create their uplifting melodies - Study Finds
The bird voice box is one of a kind in the animal kingdom | Science | AAAS
The syrinx - ScienceDirect
Voice research
Syrinx (bird anatomy) - Wikipedia
In situ vocal fold properties and pitch prediction by dynamic actuation of the songbird syrinx | Scientific Reports
physiology - Do birds have pharynx like mammals? - Biology Stack Exchange
Birds Singing : Twootz.com
vocal folds
The Oldest Bird Voice Box Ever Found - The New York Times
Parrots Don't Have Vocal Cords | Veterinary Hub
Roaming Passerines - Bird Calls & Bird Songs - Wysinfo Docuwebs
Why can parrots talk like humans? Can they imitate any language they hear? - Quora
biology - Feasability of having a voice modulator bioengineered into vocal chords? - Worldbuilding Stack Exchange
The Scorpion and the Frog: Who Said What? (A Guest Post)
The vocal organ of hummingbirds shows convergence with songbirds | Scientific Reports
Bird communication
How does a bird's syrinx function? - Quora
The structure and life of birds. Birds; Evolution. VI FORM AND FUNCTION 137 important respects, the same as that of the human larynx. There are two membranes corresponding to those called
No Feather Left Behind: How Do Birds Talk Without Vocal Chords?
Vocal tract anatomy of king penguins: morphological traits of two-voiced sound production | Frontiers in Zoology | Full Text
