There are seven kinds of cranes in the Yellow River Estuary, namely, white crane, white-naped crane, white-headed crane, red-crowned crane, gray crane, demoiselle crane and sandhill crane. In view of the protection of birds in the Yellow River estuary, it is an important factor for cranes to stay in the Yellow River estuary for a long time to build bird habitat islands in nature reserves, implement ecological water replenishment, implement water level control, implement closed management of core areas, control human activities, and provide a safe rest environment for cranes.