An endangered species of bird, introduced to Hong Kong by British military chiefs in the 1940s, has hatched one of the largest captive-turned-wild populations of its type in the world. The sulphur-crested cockatoo can be found between Pokfulam and Happy Valley and also in the Sai Kung area, according to the Hong Kong Bird Watching Society's newly published book The Avifauna of Hong Kong. The parrots, which are indigenous to Sulawesi, in Indonesia, were first spotted in Hong Kong in 1941. They are believed to have been released by former British military chiefs at Flagstaff House in Central before the Japanese invaded Hong Kong. The number of cockatoos in Hong Kong had grown to 53 by 1987, and the present-day population is about 100. There are about 6,000 such birds worldwide, most of them in Indonesia, where their habitat is under threat from excessive logging. The Bird Watching Society believes Hong Kong now accommodates the largest number of captive-turned-wild cockatoos bred from their released ancestors. However, they are worried that their habit of tearing off tree bark and boring holes for nests in trees could pose a threat to other birds. 'We once thought they should be sent back to their place of origin. But we were told by international experts that their forest homes have been destroyed because of . . . excessive logging,' Lam Chiu-ying, chairman of the society, said. Bird watchers in the mid-1960s found that the cockatoos had driven out other species in Hong Kong, including the rare rose-ringed parakeet. Dr Lam said that had the British not released the exotic species, they would probably never have found their way to Hong Kong. Of the 488 bird species found in the SAR, about 100 are exotic and were released into the wild by people. He said the British had been both keen bird watchers and bird hunters. Bird hunting was outlawed in 1976 as part of the former colonial government's widespread animal hunting ban. There are about 100,000 records of birds, compiled mostly by British bird watchers between 1957 and 1970, Mr Lam said. These records were recently donated to the Museum of History. Museum chief Ting Sun-pau said the records would be used to help study the history of Hong Kong's birds for conservation purposes.