XI'AN - A total of 20 crested ibises were released into the wild in Northwest China's Shaanxi province on Saturday, local authorities said.

Satellite trackers have been placed on five birds, helping researchers to understand the living conditions of the released birds, and study their foraging, reproduction and migration behaviors in the wild, while conducting scientific research aimed at restoring their long-distance migration.

The crested ibis, with its iconic red crest and long black beak, was thought to be extinct in China until seven wild birds were observed in Shaanxi in 1981, a discovery that prompted captive breeding and enhanced protection of the species.

It is estimated that there are more than 5,000 crested ibises in the world now, and about half of them live in Shaanxi province.