Your sentence is almost perfect! Here is the original sentence:
‘The forest is most beautiful in springtime, when everything is waking up from winter. Bird songs are getting louder as more birds are coming home.’
Great job! It's clear and easy to understand. Just a couple small tips:
1. You can add the word ‘the’ before ‘bird songs’ to make it sound even better: ‘The bird songs are getting louder…’
2. Instead of 'are getting louder', you can also say 'grow louder' to make it a bit more descriptive.
So you could say:
‘The forest is most beautiful in springtime, when everything is waking up from winter. The bird songs grow louder as more birds come home.’
Remember, both versions are correct and your original is already very good!