孔雀东南飞

The title and opening line of a famous Han-dynasty yuefu ballad 《孔雀东南飞》, China's longest ancient narrative poem. It tells the tragic love story of Liu Lanzhi (刘兰芝) and Jiao Zhongqing (焦仲卿), driven to suicide by a domineering mother-in-law. The opening line 孔雀东南飞，五里一徘徊 - 'The peacock flies southeast, circling every five li' - uses the bird's reluctant flight as an omen. Modern Chinese repurposed the phrase for the talent drain toward the southeast coast.

In modern usage the tragic-romance meaning is almost gone - it's now primarily a headline phrase for talent migration out of central/western China toward Beijing, Shanghai, Guangdong, etc.