。
She watched the little bird carefully.
Literal
She [topic-は] little-bird [object-を] carefully gazed-at.
小鳥 (ことり, 'small bird, songbird') uses the diminutive prefix 小 (こ-). 注意して (ちゅういして, 'carefully, with attention') is the te-form of 注意する ('to pay attention'). Combined with 見つめる ('to gaze at'), it creates a scene of focused, attentive observation.