Direct payments for the protection of biodiversity (a type of payment for environmental services) have
been proposed as an effective tool for delivering conservation outcomes, in a way that also delivers development
benefits to local people. Using an impact evaluation framework, this paper analyses the effectiveness
of a direct payment program that was established for nine globally threatened bird species in the
Northern Plains of Cambodia. The program provided conditional payments to local people to protect
nests, since most of the species were highly threatened by the collection of eggs and chicks. Since the program’s
inception in 2003 it has protected >2700 nests over >2000 km2 of habitat at a cost of $30,000
annually, with 71–78% of the costs paid directly to local people. Payments significantly improved the success
rates of protected nests in comparison with control sites, leading to population increases for at least
three species. However, payments did not influence other threats to species, such as land clearance, and
have failed to arrest declines in at least one species’ population. The average payment per protector was a
significant contribution to incomes in remote rural villages. However, the program only benefited a small
proportion of people, causing some local jealousies and deliberate disturbance of nesting birds. The program
demonstrates that direct payments can be a highly effective conservation tool in those cases where
payments correctly target the cause of biodiversity loss. The results also suggest that it is important to
consider how decisions over beneficiaries are made, especially in situations where property rights over
biodiversity are unclear, if payments are to be socially acceptable. This has important implications for
the design of payment schemes in conservation more generally.