Anton Schindler
Beethoven's student, Carl Czerny, and biographer Anton Schindler, both suggested that the composer got the idea for the first four notes of his 5th symphony from the yellowhammer's call, although more likely the opening of the 4th Piano Concerto was actually the work in question. Beethoven also used the yellowhammer theme in two piano sonatas, no. 21 in C major (the "Waldstein", Op.53) and No. 23 in F minor (the "Appassionata", Op.57).