In what month do seagulls leave Tianjin Haihe River?

March and April. In March and April every year, these seagulls leave Jincheng and fly to Siberia, Australia and other regions. In winter, a large number of seagulls fly from Siberia and spend the winter in Haihe. The seagull flew more than 6,000 kilometers just to fulfill the "one period, one meeting" agreement with Tianjin people and meet you in Tianjin.