BEIJING – With a slow and hesitant step into the unknown, a lumbering lump of black and white fur called Lucky will today become the first captive-born giant panda to be released into the wild.

More than a quarter of a century after setting up the first breeding reserve for the world’s favorite endangered species, China’s government announced yesterday it was time to put the product to the test.

Xiang Xiang, whose name means auspicious or lucky and who is four years old, has been carefully chosen and prepared for his big adventure. He was selected for “habitat training” at the age of two, the head of the Wolong Giant Panda Protection and Research Center in the bamboo-covered hills of Sichuan province, Zhang Hemin, said.

At first he was given an area of five acres to acclimatize himself to the wide open spaces, and then an area 10 times that. In the two years he spent there, he was taught how to build a den, forage for food, and mark his territory. He can also howl and bite, Mr. Zhang said.

Lucky will not be left entirely on his own. He will be tagged and his whereabouts monitored by GPS satellite.

The decision to return some of the 180 pandas in captivity round the world to their natural habitat comes at an interesting time in the breeding program’s history.

Wolong was established by the government along with the World Wide Fund for Nature (now WWF), which has long made the panda its symbol, in 1980. But WWF later pulled out, and says that the focus of conservation efforts should be on preserving the animals’ habitat, half of which has been lost to logging, agriculture, and human development in the past three decades.

Recently, American zoos, which pay $1 million a year to the Chinese government for each panda they have on show, have also begun to question the viability of the arrangement.

A survey in 2004 conducted by the State Forestry Administration and WWF proved good news, revealing that there were about 1,600 pandas surviving in the wild, 500 more than previously thought. But this also raised questions about the immediate need for a breeding program on the scale of China’s.

The decline in panda numbers began to be noticed when they were hunted for food in the great famine of 1959-62 and continued with poaching .