Black-necked cranes play in sunny spring in the National Natural Reserve located in the Lhoka Prefecture of southwest China's Tibet Autonomous Region, March 26, 2012. [Photo/Xinhua]

As ice thaws, mild wind blows, an increasing number of black-necked cranes, under first-class state protection, embrace the sunny spring in southwest China's Tibet Autonomous Region.

The cranes forage, play and mate in the vast field of the National Natural Reserve in the middle reach of Yarlung Zangbo River in the southern Lhoka prefecture, at an altitude of over 3,400 meters.

The natural reserve, set up in 2005, has been well protecting the rare black-necked cranes.

The number of black-necked cranes in Tibet was only 3,910 in 1992. Later, the number constantly increased as several reserves for black-necked cranes were set up in the last few decades.

At present, Tibet has more than 8,000 black-necked cranes, over 80 percent of the world's total.