Your sentences are mostly correct and easy to understand! Here’s a slightly improved version with a few small changes to make it even clearer and grammatically correct:
Original:
During the day, the forest is full of bird singing. A giant moose munches on grass, and squirrels are busy looking for cones. When the sun sets, a lynx is out hunting to the sound of croaking frogs.
Corrected Version:
During the day, the forest is full of birds singing. A giant moose munches on grass, and squirrels are busy looking for cones. When the sun sets, a lynx is out hunting to the sound of croaking frogs.
Explanation:
- "bird singing" should be "birds singing" because there are many birds making the sounds.
- The rest of the sentences are great! They use simple words and describe the forest at different times of the day very well.