This is the 8149th most frequent Japanese word.
小鳥
Small bird.
The word 小鳥 (small bird) is used as the subject of the observation action in this sentence.
公園の木の上に小鳥が見えました。
I saw a small bird on the tree in the park.
Here, 小鳥 is generalized to represent birds collectively known for their chirping in the morning.
小鳥はさえずりで朝を迎えます。
Small birds greet the morning with their chirping.
In this sentence, 小鳥 refers to a specific bird that the children are feeding.