鸟类 niǎolèi birds Definitions Defs Origin Strokes Stroke Words Sentences Sents 鸟类学 niǎolèixué ornithology the scientific study of birds中国鸟类学会 Zhōngguó Niǎolèi Xuéhuì China Ornithological Society 祖鸟类 zǔniǎolèi ancestral birds dinosaur ancestors of birds