What you're hearing
The crickets are a soft, even bed rather than single chirps, and the frogs are a whole pond of small frogs trilling together. Both are steady enough to sleep to: nothing in them builds up or stops.
For more of the night, add the Owl or the Nightingale from Birds, or Rainforest night from Wild. The Summer night, Moonlit garden and Village night starting points are built from these. They were made with AI and are marked AI in the list.