Answer: Onomatopoeia and Alliteration
Explanation: Well in the sentence above it states they enjoy the bird's chirp
And chirp is technically a sound effect
It could also be Alliteration because blue bird both start with b.
(I hope this makes sense anyhow)
Edit: And if you need one answer I would put Onomatopoeia since there isn't any other words that start with b.
