There is considerable discussion about copyrights, intellectual property, and how all of that works in the brave new digital world on the web. Here is an article describing research into the evolution of bird songs.
Note where imitation, near neighbors, migration and competition for sex are strong determininants of the evolution of songs. Note where it is better to get one style and stick with it versus constantly having to hunt for the next new thing. Note that the preferences vary but how little the songwriter actually controls the environment in which they work, but rather have to adapt to it or find one where they fit.
Nothing about copyright impedes creativity. Territory can.