I agree it seems like AI

But if it came from anywhere it would probably be the book he published last year.

Dr Echols invented new technology allowing researchers to see anatomical features such as blood vessels with the use of CT. The Second Edition has all new images of CT based wing and leg anatomy clearly depicting important anatomic features for several avian species.

https://avianstudios.com/reviews/avian-surgical-anatomy-and-orthopedic-management-second-edition/

Which seems like a pretty credible origin to me