A sustainable revenue stream for the World Wildlife Fund (WWF) was created using the music-streaming model. The birdsong of endangered species became music samples available to artists for free, on condition that all streaming proceeds went to WWF for bird protection. It became the basis for a record label monetizing birdsong. After its launching, over 500 tracks were received, the best of which will be released on the first album. Birds will earn money while people listen to music.