A free program for Android, by Dream_Studio.

Nature sounds: relax and sleep is an application that allows you to listen to the most relaxing and beautiful nature sounds: birdsongs, winds, water, forest, rain, and sea. All you have to do is set the app to run in the background and put it on your phone’s home screen or lock screen. It’s that simple!

It is perfect for those who want to relax, meditate, concentrate, or just have problems with insomnia. If you have time for a short break, just press the play button and enjoy a few minutes of peace. The application can run in the background or on the screen off.