Thrush nightingales migrate to Africa during winter. While there, they experiment with new songs to impress mates during the spring breeding season in Europe
Source:
https://www.newscientist.com/article/2224840-nightingales-practice-new-songs-in-winter-to-impress-mates-in-spring/?utm_campaign=RSS%7CNSNS&utm_source=NSNS&utm_medium=RSS&utm_content=home