Context:
On GitHub, you can see which branches have you created (see “Your branches” section of “Branches” page).
Problem:
In GitHub API, there is no way to get the creator of the branches. The return values of GitHub References API don’t contain the creator of branches. https://developer.github.com/v3/git/refs/
Solution:
There is no workaround about it (or you have to retrieve html and scrape it).