This is the 3776th most frequent Japanese word.
とり
Bird.
The word '鳥' in this sentence is used to denote birds, general avian species living in the forest.
この森には多くの鳥が住んでいます。
Many birds live in this forest.
Here, '鶏' is used to refer specifically to chicken as food.
今晩のディナーに鶏のグリルを作ります。
I will prepare grilled chicken for dinner tonight.
In this usage, '鳥のように' metaphorically implies grace and freedom related to a bird.