Natural musical instruments
There's music in nature. Listening to nature, you can hear music everywhere. The blowing of the wind, the tapping of the rain, the babbling of a river over the stones.. Crickets make sounds and frogs that croak, the birds that sing.. I can even hear the snails slurping on the wet leaves. You have to hear it, but if you focus on it, there's a pretty nice beat in it! The rustling of the reed stems, walking along a gravel path.. You should record it sometime and then you can make great music out of it.
With natural materials you can also make small music (instruments).
I did not try it all myself, but here are some funny tips. If you have additional tips, they are welcome!

1. Whistling on a blade of grass

2. Roll up lilac leaf as a whistle