Unmanned aerial vehicles (UAVs) are useful tools in ornithological studies. Importantly, though, UAV-caused disturbance has been noted to vary among species. This study evaluated guidelines for UAVs as a tool for researching geese. Twenty-four flocks of foraging geese were approached at an altitude of 50–100 m with a quadcopter UAV and disturbance effects were analysed across different horizontal distances between the UAV and the flocks. Geese were increasingly disturbed when approached by a UAV, with birds showing increased vigilance behaviour within approximately 300 m. Increasing UAV flight altitude as well as increasing take-off distance from the flocks both decreased the risk of bird flocks flushing. In conclusion, when monitoring geese using UAVs, flight altitudes of 100 m and take-off distances of ideally ∼500 m are recommended, to minimise initial disturbance and reducing the risk of birds flushing.

Farmland bird populations in Germany are declining at a higher speed than species inhabiting other habitats. We studied potential causes for bird population changes based on data from standardised German breeding bird monitoring schemes. We related population trends to covariates describing the changes in the agricultural landscape in Germany, weather conditions during the breeding season and for some migratory species, conditions at stopover and wintering sites. Linear mixed effect models were used to analyse effect strength at species level and conclusions are drawn for the overall group of farmland bird species. The area of grassland and fallow land was shown to have the strongest positive effects and the area of maize and rapeseed the strongest negative effects on farmland bird population trends. The results obtained also indicate that despite the consistent influence of weather conditions during the breeding season, land-use changes had a stronger impact on bird populations than weather. Conditions at Sahel wintering sites did not show a consistent effect on population trends. Based on these findings the study quantitatively underpins and ranks key factors shaping farmland bird populations in Germany.

The Volcanoes National Park (VNP) in Rwanda, part of the Virunga massif in the Albertine Rift region, boasts some of Rwanda’s best remaining natural vegetation and is home to many endangered and endemic species. The park has suffered from high levels of degradation and destruction, reducing in size by 50% during the 1960s and 1970s, and remains under threat from illegal activities, human population pressure and climate change. This study is the first to investigate the status and trends of bird communities in the VNP, using a multi-year dataset. We use a five-year dataset, totalling over 3,200 point-counts, both within and around the VNP, to assess the conservation value of the VNP for birds in comparison with other national parks and non-protected areas. We assess bird communities and population trends within and around the parks and identify important habitat factors for birds within the VNP. We found that the VNP hosts a unique bird community compared to other localities, with several Albertine Rift endemics and threatened species occurring in the VNP. Hagenia/ Hypericum woodland, herbaceous vegetation, brush ridge and mixed forest host the highest levels of bird diversity in the VNP, whilst the park’s waterbodies provide key habitat for the endangered Albertine Rift endemic Grauer’s Swamp-warbler (Bradypterus graueri). Elevation had a negative effect on bird diversity in the VNP, whilst the basal area of dead trees, Hagenia and vines had a positive effect. Both inside and outside the VNP, there was a significant decline in abundance and species richness over the sampling years; however, we advocate for further monitoring to confirm these trends. Based on our findings, we recommend effective, targeted management of key habitats for birds within the park, including those identified in this study, in order to mitigate bird declines and conserve the unique bird communities in the VNP.

Mediterranean mountains are biodiversity hotspots where northern species occur surrounded by drier and warmer lowlands. In this context, global warming is pushing these species to higher elevations. This paper assesses whether forest birds have experienced a shift upwards over the elevation gradient in the last 35 years in the Guadarrama Mountains (600–2,400 m asl; central Spain). Alternatively, the paper tests whether the reported shifts are related to changes in forest structure resulting from rural abandonment and/or forest management. To do this, sampling carried out from 1976 to 1980 along the elevation gradient was repeated in 2014–2015. In addition, the habitat preferences of birds were used to test if the elevation shifts were related to changes in forest structure. Results show that the mean range position of birds associated with tree cover shifted downwards, a trend supported by an increase in tree-dependent birds at mid-elevations. These trends suggest that an increase in tree cover has buffered the altitudinal shifts of forest birds predicted by climate warming. Results also suggest that proper forest management may improve the resilience of forest bird communities to the pervasive effects of climate warming.

The Rio Branco is a river with unique biogeographic and ecological features, threatened by the Brazilian Government’s plan to build a major hydroelectric dam and associated hydroway along its course. The river crosses one of Amazonia’s largest rainfall gradients and a major geomorphological boundary along a savanna/forest ecotone, marked by the Bem Querer rapids. Above the rapids, the upper Rio Branco runs through the Boa Vista sedimentary formation and crosses the crystalline rocks of the Guiana Shield, and its margins are flanked by gallery forests. Downriver, it runs through a low-lying sedimentary basin, with Amazonian floodplain forests along its margins. Here, we present the results of ∼ 15 years of ornithological research on the Branco and its major tributaries, providing baseline data and evaluating potential threats to the riverine avifauna. Our surveys included opportunistic observations and standardized surveys along the entire length of the river in 16 systematically distributed localities. We catalogued 439 bird species, 87% of which are documented by physical evidence (specimens, recordings, photographs). Forty-six percent are restricted to single habitats, suggesting a high degree of habitat specialisation. A third of the species are widely distributed along the river, whereas 45% are restricted to either the upper or the lower Rio Branco, including 40 and 30 Indicator Species, respectively. Twenty-five species are threatened at global or national levels, including two ‘Critically Endangered’, nine ‘Vulnerable’, and 14 ‘Near Threatened’. We present a list of 50 bird species that are candidates for monitoring studies. Threats to the avifauna from dam construction include permanent flooding above the dam, eliminating gallery forests, river islands, and sandy beaches, and the disruption of the flood pulse along the river, affecting river island and floodplain forest specialists, many of which are globally threatened with extinction. If built, the Bem Querer dam will wipe out the ecotone region and affect dramatically the river’s avifauna.

The Altamira Yellowthroat Geothlypis flavovelata is endemic to north-eastern Mexico, with a restricted distribution due to the spatial arrangement of its major habitat: wetlands. Given the lack of information regarding this vulnerable and endemic landbird, here we describe and analyse the sites where we recorded it in Northern Veracruz, as well as its population density, and natural history information. Our results show that the average density of this endemic yellowthroat is 1.006 ind/ha, with more individuals recorded in Tecolutla when compared to Tuxpan. We found a strong association between the Altamira Yellowthroat and southern cat-tail Typha domingensis, although we found scenarios under which the presence of the cat-tail was not a determinant of Altamira Yellowthroat presence. In light of the strong anthropogenic pressures on wetlands in the region, the Altamira Yellowthroat has become highly vulnerable. Thus, if we aim to preserve this endemic species, together with other wetland-dependent species, it is crucial to moderate –and even stop– human pressures on these ecosystems and mitigate past damages.

With a decline exceeding 30% over three generations, the once-common European Turtle-dove is now considered globally threatened by IUCN. As a legal game species in 10 European countries, the recent International Single Species Action Plan for this species highlighted the need to carry out an assessment of the sustainability of current levels of hunting. In 2013–2014, the Western European population was estimated at 1.3–2.1 million pairs, and the hunting bag in the same region to be 1.1 million birds. Using the Demographic Invariant Method, we assessed whether current levels of hunting harvest within Europe constitute overexploitation of the western flyway European Turtle-dove population. We calculated the maximum growth rate λmax that a population might achieve in the absence of any additive mortality. Then we estimated the potential maximum harvestable population fraction (P) allowed by excess population growth. We explored a wide range of plausible scenarios relating to assumed demographic rates, geographic scope of the flyway and management objectives. λmax was estimated to lie between 1.551 and 1.869. Current levels of hunting along the western flyway are more than double the sustainable fraction (P) under all suitably conservative scenarios, and only fall below this threshold under the most restrictive assumptions. We conclude that current levels of legal hunting along the western flyway are unlikely to be sustainable. Reducing uncertainty associated with assessments of the sustainability of turtle dove hunting will require improved information on (in order of decreasing importance) current levels of hunting, adult survival, age structure and population size.

For Greater Scaup Aythya marila, classified as ‘Vulnerable’ on the European Red List of Birds, the south-western Baltic Sea is one of the most important wintering sites in Europe. In this area, a large concentration of gillnet fishery temporally overlaps periods of the most abundant occurrence of foraging diving birds. The aim of the article is to show how bycatch can impact the population of a diving duck. To assess this, we calculate the Potential Biological Removal (PBR) for the studied Greater Scaup population and we model the population change according to age-structured matrix models. Summing all the available recent figures on Greater Scaup bycatch in north-west Europe yields an estimated mean annual total of 3,991 individuals (2% of the flyway population). For a baseline stable population, an age-structured matrix model indicates that at this bycatch level the Greater Scaup population that winters in north-west Europe will decrease by 36% over the next 30 years, qualifying the status of the population as ‘Vulnerable’ according to IUCN criteria. As this population also experiences decline prior to bycatch, this decrease will be 57%, which qualifies the status as ‘Endangered’. PBR as an indicator of population vitality does not work in our case because the PBR-informed allowable bycatch values have a significantly negative impact on the population. Our results indicate unambiguously that fishery bycatch is among the most important threats responsible for the Greater Scaup’s decline. While recent data suggest that some improvement has taken place in the species’ status over the last 10 years, measures to protect Greater Scaup from bycatch are required. The solution should involve the prohibition of gillnet fishing in selected key sites and the use of mitigation techniques in other areas.

Despite the global significance of the Leach’s Storm-petrel Hydrobates leucorhous colony on Baccalieu Island, Newfoundland and Labrador, Canada, the estimate of 3.36 million breeding pairs reported for 1984 by Sklepkovych and Montevecchi stands as the single published population estimate for the world’s largest colony. This study increases knowledge of this population by analysing data from additional independent surveys conducted in 1984 and 1985, and by updating the population status with a survey conducted in 2013. Population estimates were derived by extrapolating occupied burrow densities to the estimated occupied area of four main habitat types (heath, forest, grass and fern), which in turn were based on proportions of habitats observed in plots (1984 and 1985) or by using a Geographic Information System approach (2013). Based on these surveys, the Leach’s Storm-petrel breeding population size on Baccalieu Island was estimated at 5.12 ± 0.73 (SE) and 4.60 ± 0.42 (SE) million pairs in 1984 and 1985 respectively, representing estimates 37–51% greater than the original 1984 survey. While discrepancies among these estimates were largely driven by the way occupied areas were estimated, our study confirms that Baccalieu Island hosts the largest Leach’s Storm-petrel colony in the world. Results from the 2013 survey estimate the current breeding Leach’s Storm-petrel population at 1.95 ± 0.14 (SE) million pairs, representing a 42% decline over 29 years (-1.4% per year), relative to the original published estimate of 3.36 ± 0.12 (SE) million pairs. The most prominent change has occurred in the density of storm-petrel burrows found in forest habitat which dropped by 70% despite forest remaining the second most abundant habitat available to nesting storm-petrels on Baccalieu Island. The cause of this decline remains unknown and is likely multi-faceted. Future research focusing on demographic studies is required to understand what is driving the population decline of this internationally important colony.

Cipo Canastero Asthenes luizae is a relict ovenbird restricted to rocky outcrops at high elevations within the campo rupestre vegetation of the Espinhaço Range in the state of Minas Gerais, south-eastern Brazil. This poorly known species is considered ‘Near Threatened’, but recent studies have suggested that it should be listed under a higher category of threat. To contribute to the knowledge of this species and its conservation assessment and related planning, we compiled all literature records of the species distribution (n = 16 locations), collected new data on its occurrence (n = 72 locations), and calculated its geographic range using four different approaches. First, we defined the sky islands where the species occurs (nine units) using the lowest elevation value recorded (1,100 m asl) as a cut-off. Second, we performed species distribution modelling (SDM) across the sky islands and identified an area of 2,225.21 km2. Third, we measured the species’ extent of occurrence (EOO = 24,555.85 km2) and used SDM to estimate its upper limit (EOOup = 30,697.58 km2). Fourth, we measured the area of occupancy (AOO = 228 km2) and used SDM to estimate its upper limit (AOOup = 1,827.39 km2). We analysed the Cipo Canastero sky islands in terms of landscape metrics including size, isolation, protected area coverage, shape index, core area index, and proportion covered by SDM. We observed a very fragmented distribution, especially in the North sector of the species distribution, composed of small and isolated populations (separated by up to 112 km); the South sector is the core of its distribution and is composed of larger, more connected patches with differences in shape complexity that are not strongly influenced by an edge effect. The range sizes calculated, along with other reported information regarding population and habitat trends, justifies the inclusion of the species in at least the ‘Vulnerable’ category.

The White-winged Snowfinch Montifringilla nivalis nivalis is assumed to be highly threatened by climate change, but this high elevation species has been little studied and the current breeding distribution is accurately known only for a minor portion of its range. Here, we provide a detailed and spatially explicit identification of the potentially suitable breeding areas for the Snowfinch. We modelled suitable areas in Europe and compared them with the currently known distribution. We built a distribution model using 14,574 records obtained during the breeding period that integrated climatic, topographic and land-cover variables, working at a 2-km spatial resolution with MaxEnt. The model performed well and was very robust; average annual temperature was the most important occurrence predictor (optimum between c.-3°C and 0°; unsuitable conditions below -10° and above 5°). The current European breeding range estimated by BirdLife International was almost three times greater than that classified as potentially suitable by our model. Discrepancies between our model and the distribution estimated by BirdLife International were particularly evident in eastern Europe, where the species is poorly monitored. Southern populations are likely more isolated and at major risk because of global warming. These differences have important implications for the supposed national responsibility for conservation of the species and highlight the need for new investigations on the species in the eastern part of its European range.

Renewable energy helps meet the growing energetic demand while reducing greenhouse gas emissions. Despite its environmental benefits, production of wind energy can adversely affect wildlife populations, including birds. In some species, indirect impacts such as habitat loss and disturbance may be more important than fatalities caused by collisions with turbines. Bicknell’s Thrush Catharus bicknelli, one of the most endangered bird species in North America, may be threatened by wind energy production because it breeds at high elevation sites, which are often prized for their wind potential. Our study had two objectives: we first aimed to document the impacts of the construction and operation of a wind energy facility without mitigation strategy on the occurrence of the Bicknell’s Thrush. At a second facility, we then tested the effectiveness of turbine micro-siting as an effective mitigation strategy to reduce the impacts of wind-energy development on the species. We conducted avian point-counts at 143 locations spread across both facilities in Quebec (Canada) at different periods: before, during and after construction. We modelled the probability of occurrence of the species at point-counts as a function of period, forest loss caused by wind energy development, distance to the nearest turbine and habitat suitability. At the facility without mitigation, we found that the probability of occurrence decreased during construction and early operation at high elevation sites, where most of the turbines were erected. However, the Bicknell’s Thrush recolonized high elevation sites eight years post-construction. In addition, we did not detect a significant impact of wind energy production on the species’ occurrence at the facility where micro-siting was applied. We conclude that habitat loss and disturbance during construction are the main impacts of wind energy production on the Bicknell’s Thrush and that micro-siting appears to be a promising mitigation strategy.

The Beck’s Petrel Pseudobulweria beckii is a ‘Critically Endangered’ seabird whose breeding sites remain unknown. Historic observations suggest the species’ distribution is concentrated in the Bismarck Archipelago and particularly southern New Ireland. Over the course of two research expeditions in 2016 and 2017 we used on-land and at-sea observations, local interviews and satellite telemetry to understand the distribution of the species, its at-sea movements and potential breeding locations. Land-based and at-sea observations indicated that the area of Silur Bay in southern New Ireland was a significant site for Beck’s Petrel with numbers of birds increasing near shore prior to dusk and birds observed in spotlights over land. A local population is estimated to be in the low thousands. In 2017 a single Beck’s was captured at sea, fitted with a satellite transmitter and tracked for eight months. This bird maintained a core distribution off the south-east coast of New Ireland and north of Bougainville for 122 days. During the tracking period, the bird was located over land at night seven times; predominantly over southern New Ireland, where the signal was also lost for extended periods suggesting occupancy of an underground burrow. In August the bird migrated 1,400 km to a core pelagic habitat north of West Papua before the signal was eventually lost. Our combination of land- and sea-based observations and analysis of behaviour from satellite tracking supports the conclusion that a breeding site for Beck’s Petrel lies in the inland mountains of southern New Ireland and most likely in the high-altitude zone (> 2000 m) of the Hans Meyer Range. Further investigations are required to determine the exact location of breeding colonies in the mountains of southern New Ireland and the importance of a potential west Papuan non-breeding pelagic habitat for the species.

Galliformes are one of the most threatened groups of birds in South-East Asia, with 27% of the species threatened with extinction. Long term population viability and extinction probability studies, at different levels of threat and management, are lacking due to weak life history data. This study aimed to define the long-term viability and extinction risk of two populations of the endangered Green Peafowl Pavo muticus, facing different threat and protection levels, using Bayesian Population Viability Analysis (BPVA), which requires less data than traditional methods. The results showed an increasing trend in the Green Peafowl population in HuaiKhaKhaeng Wildlife Sanctuary (western Thailand), with a high protection level and low disturbance and high probability of assuring persistence for the next 100 years. By contrast, the population in YokDon National Park (south-central Vietnam), with a high habitat disturbance level and significant hunting pressure, is predicted to decline and has a high probability (99%) of extinction by 2097. Also, the BPVA showed minimum viable population (MVP) estimates of 250 and 450 calling males for the HuaiKhaKhaeng and YokDon populations respectively, assuring high probabilities of long-term persistence if the minimum numbers of males are available. The population size of 219 calling males at YokDon during the 2013 survey is lower than the MVP threshold of 450 calling males, which suggests the species has a low probability of long-term persistence in the area. Despite limited life history and population data, BPVA predicted the future of this population under site-specific conditions, and the results could be used to promote better management and population restoration.

We documented the consequences of large-scale habitat loss on a community of Galápagos native bird species on San Cristóbal island, based on point counts conducted between 2010 and 2017. Surprisingly, despite considerable habitat change and a variety of other threats, the landbirds of San Cristóbal have fared much better than on the neighbouring islands Floreana or Santa Cruz. While two species went extinct very soon after human colonisation, the majority have adapted well to subsequent vegetation change and habitat loss. The endemic San Cristóbal Mockingbird Mimus melanotis is more widespread than previously thought and its population seems to be stable since the 1980s. We thus propose a change in IUCN classification from ‘Endangered’ to ‘Near threatened’. We present evidence gained by interviewing locals which suggests that a small population of the Least Vermilion Flycatcher Pyrocephalus dubius, classified as ‘Extinct’ by BirdLife International, may have persisted until very recently. Although extensive searches in 2018 and 2019 were unsuccessful, the possibility remains that a few birds may have survived in remote parts of the island. Further searches that involve the general public and other interested parties are therefore deemed necessary.

Reintroduction to, or reinforcement of, threatened wild populations are commonly used conservation strategies. Reintroductions of the Southern Ground-hornbill Bucorvus leadbeateri have been tested as a potential conservation tool for this vulnerable species since 1995. Forty-two individuals have been reintroduced under varying management strategies. We analysed the outcomes of these attempts to assess which factors contributed most to success or failure. The species exhibits complex social learning and hierarchy, and is long-lived, with delayed sexual maturity. Immediate survival was significantly affected by the season in which the release was done and by the quality of the released birds. The best-quality release birds were reared with wild behavioural characteristics and were well-socialised to captive conspecifics prior to being placed into managed groups (‘bush schools’), where social learning was led by an experienced, wild alpha male. Once reintroduced birds had survived their first year after release, continued wild experience and wild mentorship significantly affected their survival. Since sample sizes limited the rigour of some statistical analyses, other factors were considered that may also determine success. These quasi-experimental reintroductions revealed novel threats to the species, such as the importance of a nest to group cohesion, that harvested second-hatched chicks provide viable release birds, which essentially doubles wild productivity, and that reintroductions generate valuable civil society awareness of the plight of the species.

Human activities are altering ecosystems and threatening the well-being of wildlife. The study of the stressful effects of human disturbances on animal distribution, physiology and behaviour can provide fundamental insights for wildlife conservation. Here, we assess how two declining birds, the European Roller Coracias garrulus and the European Scops Owl Otus scops, cope with alteration by human activities in farming habitats of the south of Spain. We studied nest distribution, quantified nestling physiology (corticosterone levels in plasma and feathers and body weight close to fledgling) and parental behaviour (feeding rates) of both species along a human alteration gradient. Rollers and Scops Owls used the same type of habitat and their spatial distribution was not determined by individual quality. In Rollers, nestlings raised in scrubland areas had high stress-induced corticosterone levels, possibly due to high predation risk in this habitat. In addition, Rollers and Scops Owls showed opposite relationships with farming activity and human disturbance. Nestling Rollers showed the highest corticosterone levels in feathers, weight and parental feeding rates in areas with intense farming activity. These results suggest that despite the disturbance produced by farming activities, inducing a higher stress in these areas, cultivated areas may, simultaneously, provide parents with a higher abundance of prey which would trigger increased feeding rates and, hence, higher nestling weights. Furthermore, nestling Scops Owls showed the highest stress-induced corticosterone levels in areas close to roads, suggesting that they would be affected by human disturbance due to infrastructures that disturb also at night when Scops Owls are active. Therefore, susceptibility to human disturbance may vary between species, probably due to variation in the daily pattern of human activities and the species’ activity rhythm, buffering or exacerbating the effects, which should be considered in future studies on human alterations and birds.

The Rufous-throated Dipper Cinclus schulzi is endemic to the Southern Yungas of north-western Argentina and southern Bolivia. The species is categorised as ‘Vulnerable’ on the IUCN Red List on the basis of small population size and restricted range. The purpose of our study was to determine the distribution of potentially suitable habitat for the Rufous-throated Dipper, estimate its population size, and assess potential distribution within strict protected areas, in north-western Argentina. We surveyed 44 rivers in the Southern Yungas of Argentina from 2010 to 2013 to determine dipper density (i.e. the number of individuals detected per km surveyed). The dipper’s potential distribution was assessed using a maximum entropy modeling approach based on 31 occurrence points and eight bioclimatic and two topographic variables as predictors. The species is dependent on mountain forest rivers, so the potential distribution was restricted to rivers. We estimated dipper population size by multiplying density by the potential distribution along rivers. Finally, we calculated the extent of suitable habitat contained within the boundaries of Argentina´s National Parks. Dipper density was 0.94 ± 1.55 individuals/km. We estimate that within north-west Argentina there are ~2,815 km of river that are potential habitat, with an area of occupancy of 141 km2 and a population size of 2,657 ± 4,355 dippers. However, of this river extent, less than 5% is within National Parks. Our results highlight the need to create new and to enlarge existing National Parks that protect the potentially suitable habitat of the species. Although more information is needed for Bolivia, the country-level area of occupancy and population size of the dipper found in Argentina provides strong evidence that the IUCN Red List classification of this species as ‘Vulnerable’ is warranted.

The Vietnam Pheasant Lophura edwardsi (including L. hatinhensis) is only known from a small area of central Vietnam, where it occurred in wet forest below 300 m. It is probably extinct in the wild, but some 1,500 birds, derived from 28 individuals caught in 1924–1930, survive in captivity. Guidelines for reintroducing galliforms date from 2009. Subsequent literature was reviewed for new research findings to help maximise the chances of success in reintroducing birds. Studies confirmed that non-parent-reared captive-bred galliforms survive poorly, primarily owing to inadequate anti-predator responses. These reflect both genetic and ontogenetic unsuitability to wild conditions, with progressive maladaptation of stock being related to the number of generations spent in captivity (at least 35 in the case of Vietnam Pheasant). To compensate as far as possible for this deficiency, a reintroduction programme should use: environmental enrichment (including the provision of perches in aviaries), dietary enrichment (especially involving practice with live food), parent-rearing over several generations (although how many are needed for a species almost a century in captivity is unknown), soft releases (allowing full familiarisation with the future environment over at least 50 days), rigorous anti-predator training (against both air and ground attacks), anti-predation release stratagems (relocating and deterring predators, releasing birds at several stations, offering post-release support), determining appropriate numbers (per batch, with at least 300 in total per site) and time-frame for release (around five years) and the selection of fully suitable releasees in (as far as possible) naturally formed social groups, including parent-guided offspring aged around four months. Six sites need survey for extant populations or use for reintroduction, and the choice of reintroduction site will depend primarily on habitat extent and condition. The costs of these measures will be high and the overall project schedule will need to extend beyond the overall five years currently planned.

Information on the geographic distribution of a species is fundamental for its conservation. Nonggang Babbler Stachyris nonggangensis (NB) is a rare and newly discovered species that is restricted to limestone karst forest on the Sino-Vietnamese border and has been classified as ‘Vulnerable’ due to its narrow distribution. However, the extent of the habitat suitable for NB is poorly known. We conducted a species distribution model (SDM) using 33 occurrence data and nine environmental variables. The SDM suggested highly suitable habitat covers 541 km2, and habitat with a medium and low level of suitability covers 3,218 km2 and 722 km2, respectively. Of the entire suitable habitat (low through high), 25.8% is in northern Vietnam and the rest is in Guangxi Zhuang Autonomous Region, southern China (especially concentrated in northern Longzhou and southern Daxing Counties). Unfortunately, only 12.4% of the entire suitable habitat is known to be occupied, and the habitat outside the reserves is highly threatened by fragmentation and degradation. Globally, NB is apparently isolated in only four sites, including one site in which we discovered its presence during field validation of the model. Based on this work, we suggest upgrading NB to the ‘Endangered’ category on the IUCN Red List and adding it to the list of endangered species of both China and Vietnam.