In the 1980s, the IUCN's red list designated the bird as "critically endangered" because its population numbered just seven.
Widely believed to bring good luck in China, it has witnessed stable population growth, rebounding to 5,000 worldwide after decades of conservation efforts. Construction of the Xi'an-Chengdu High-Speed Railway even took protection of the birds into account.
About 4,400 of the birds now live in the Giant Panda National Park, and their habitat has grown from 5 sq km in the 1980s to 15,000 sq km, according to the park's management office.
Early this year, the Hainan Rainforest National Park in Hainan province, home to China's largest rainforest and Hainan gibbons-a "critically endangered" species on the IUCN's red list-established a research institute.
It issued invitations to top experts worldwide to help protect the rainforest and endangered wildlife.
"We are calling for cooperation with experts worldwide on the management of the park as well as wildlife protection. The world's top primatologists are especially welcome," said Xia Fei, director of the park's management office.