XI'AN -- The crested ibis, with its iconic red crest and long black beak, was thought to be extinct in China until seven wild birds appeared in Yangxian county, Northwest China's Shaanxi province, in 1981. Over the years, Chinese scientists have successfully revived this tiny population to nearly 10,000.

Zhang Junfeng, 55, a key scientist behind the achievement, recalled that in 2002, the Shaanxi provincial rare wildlife rescue base, where she works, received 60 crested ibis raised at the discovery site of Yangxian.

The state forestry authority transferred the rare birds to the rescue base at the northern foot of the Qinling Mountains near the provincial capital of Xi'an to carry out captive breeding.

"In Yangxian, the species still faced a high risk of extinction. My task at that time was to let it reproduce as much as possible to ensure its survival," said Zhang.

Her team set up two breeding cages in the forest, separated by a distance of 20 meters, to combine artificial incubation with natural breeding. They took the eggs from the parent birds after about 20 to 25 days, and put them in an incubator to improve the survival rate.

When crested ibis reproduce naturally, barely one in ten chicks manage to survive. Artificial rearing of chicks can greatly improve the reproduction efficiency. A new-born chick weighs only about 50 grams.

"To feed the smallest bird, we have to use a straw as thin as 2 mm in diameter. Birds of different sizes have different food formulas," she said.

The key period for rearing crested ibis is the first 45 days after birth. Zhang often takes care of more than ten chicks a day.

Over the years, Zhang's team has successfully employed reproductive technologies in raising more than 500 crested ibis and releasing more than 140 of the birds into the wild.

In 2008, the base sent 10 crested ibis to Deqing county, East China's Zhejiang province, where Zhang's team cooperated with Zhejiang University to establish a new breeding base for crested ibis, helping build up the southern population of the species.

Since then, the Shaanxi provincial rare wildlife rescue base has provided 100 crested ibis to support the establishment of six artificial breeding bases nationwide.

Meanwhile, Shaanxi also exported 14 crested ibis to Japan and the Republic of Korea, and more than 1,000 crested ibis have been bred in those two countries.

The breeding bases have forged a concerted effort in the gradual release of birds into the wild. From the breeding base in the Qinling Mountains, the species dubbed "Oriental gem" is expected to soon reappear in more of its historical distribution areas in East Asia.