The University of East Anglia brought together a group of conservationists for a coordinated survey of 37 roost sites across Cambodia. Participants came from the Cambodian Forestry Administration and General Department for Administration of Nature Conservation and Protection, BirdLife International in Indochina, the People Resources and Conservation Foundation (PRCF), the Wildlife Conservation Society and Worldwide Fund for Nature.

The total of 429 individuals, counted simultaneously,exceeds the 2010 IUCN Red List global estimate of 330 birds by a staggering 30 %. Nevertheless, this figure may yet underestimate the true population size. Hugh Wright, a doctoral student at UEA and an expert on the species, explains:

"Discovering so many white-shouldered ibis really improves our chances of saving the species. During this record-breaking count, one of our main sites actually had far fewer birds than in previous surveys. I don't believe these birds move very far and they were probably still present at that site. Considering previous counts, this means that the actual population could even exceed 500 birds."

As well as helping to understand overall population size, the roost counts are improving knowledge of where this ibis occurs. The new findings indicate that Lomphat Wildlife Sanctuary, Ratanakiri province, is particularly valuable as over 170 birds were counted here. With up to 40 % of the known population, this site is now the second most important in the world, not far behind Western Siem Pang IBA, Stung Treng province, which has the largest known population of over 200 birds.

White-shouldered Ibis has been considered the most endangered waterbird in South-East Asia. The population declined steeply in the twentieth century, associated with habitat loss and hunting. It is now extinct from Thailand, Myanmar, Vietnam, Malaysia and southern China, and remains primarily in dry deciduous forests of north and east Cambodia. In the wet season the ibises group together at feeding and roosting sites, making it possible to count them.

Despite the larger known population, conservationists remain very concerned for this species. Mr Sum Phearun, EAU/PRCF project assistant and organizer of counts at two sites, said: "It's unlikely that the population has actually grown or started recovering. We have put more effort into searching for ibis and we're getting better coverage of roost sites, hence our larger counts. But the species is still very close to extinction so we are continuing our efforts to understand and protect the ibis."

The future is uncertain for white-shouldered ibis. Much of the population occurs outside of the protected area system in Cambodia. This species and other waterbirds are threatened by conversion of habitat for commercial plantation, agriculture and infrastructural development projects, such as the proposed Lower Srepok 3 dam, which could flood a large area of Lomphat Wildlife Sanctuary. Logging and conversion to plantation is a very significant threat at Western Siem Pang. Failure to mitigate the threats at these two sites could drive this species rapidly towards extinction.

Several donors have supported this work, particularly the Critical Ecosystem Partnership Fund, administered by BirdLife International in Indochina. Additional funding came from Chicago Board of Trade Endangered Species Fund (administered by Chicago Zoological Society), the BirdLife International Preventing Extinctions Programme and the British Ornithologists' Union. The Critical Ecosystem Partnership Fund is a joint initiative of l'Agence Française de Développement, Conservation International, the Global Environment Facility, the Government of Japan, the MacArthur Foundation and the World Bank.

Note: If no author is given, the source is cited instead.

• Nature
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