The Zhalong Marshland is China's largest region where rare water birds,mostly large ones like cranes,are found.The lower reaches of the Wuyu'er River on the Songnen(Songhua and Nenjiang rivers)Plain provide water resources for the endless reed marshland.drawing tens of thousands of birds to rest and breed here.Possessing the largest number and variety of cranes in China,the Zhalong Marshland is also one of the places with the richest species of cranes in the world.Of the 15 kinds of cranes on earth,China has nine,and Zhalong has six,among which four are endangered worldwide.There are over 2,000 red-crowned cranes in the world,and Zhalong has more than 300.