SummaryLong-term population monitoring is crucial to evaluate the effectiveness of conservation efforts. Systematic surveys of the endangered Black-faced Spoonbill Platalea minor, the rarest spoonbill species globally, are not possible during the breeding season as the largest breeding grounds are inaccessible to surveyors. Instead, we have examined population trend in this species during the winter by utilising a dataset of synchronised surveys conducted annually across 42 sites between 1997 and 2014. We found that the global population has increased from 535 individuals in 1997 to 2,726 in 2014, an annual increase of 8.0%. Population increases were more pronounced in protected sites and sites with low levels of human disturbance, indicating that control of human disturbance is crucial for conservation in this species. It is of concern that the wintering populations are highly clumped and the two largest populations have ceased to increase since 2012; research to investigate the underlying causes is urgently needed. Synchronised surveys in all known wintering sites should be continued to provide up-to-date data on the global population of this endangered species.

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The black-faced spoonbill Platalea minor is a species endemic to the coastal fringes and archipelagos of East Asia. The global population was fewer than 300 individuals in the late 1980s. Since then, two international action plans (1995 and 2010–2020) have been implemented, and the global population has increased to more than 6000 individuals in 2021–2022; the species was downlisted from “Critically Endangered (CR)” to “Endangered (EN)” in 2000. To examine the basis for this success, we reviewed the implementation of the action plans in light of the IUCN Species Conservation Cycle (Assess–Plan–Act–Network–Communicate) framework, using publicly available information documenting the planned activity or policy outcome. Additionally, we used the IUCN Green Status of Species framework to assess the impact of this conservation effort on the black-faced spoonbill’s recovery to date and recovery potential. We found that the action plans for the black-faced spoonbill contain activities across all SCC framework components, though the number of activities implemented differed among countries. Our preliminary Green Status assessment indicates that the black-faced spoonbill is currently Largely Depleted, with a Species Recovery Score of 35%; however, without past conservation actions, we estimate that its score would be only 15% today (Critically Depleted), and that it is biologically possible for the species to fully recover (100%) in the next 100 years, if ambitious actions are taken. This provides further evidence that premeditated, evidence-based conservation interventions can reverse biodiversity loss.