This is the 7968th most frequent Chinese word.
鸟类
Birds.
In this sentence, '鸟类' is used to refer to birds as a general category within the scientific field of biology.
鸟类在生物学中是一个重要的研究对象。
Birds are an important subject of study in biology.
Here, '鸟类' collectively refers to various bird species when discussing their migratory behavior.
许多鸟类具有迁徙的能力。
Many birds have the ability to migrate.
In this context, '鸟类' emphasizes the role of bird species in ecological systems and the importance of conservation.