Hans Stadler

Hans Stadler (11 April 1875 – 22 August 1962) was a German physician and naturalist. He had absolute pitch and took a keen interest in the study and description of bird calls and a wrote a book, ''Die Vogelsprache'' (1919), on the subject in collaboration with Cornel Schmitt. Along with Schmitt he made bird recordings in the field before 1914. Provided by Wikipedia