春江水暖鸭先知
chūn​jiāng​shuǐ​nuǎn​yā​xiān​zhī

the duck is the first to know the spring water is warm

春江水暖鸭先知 春江水暖鴨先知 chūn​jiāng​shuǐ​nuǎn​yā​xiān​zhī
the duck is the first to know the spring water is warm
(idiom) people in a specific environment or field are the first to sense changes or trends within it; an expert knows which way the wind blows