Herewith the UNEP/AEWA Secretariat gives a response to the paper by Vernon G. Thomas and Raimon Guitart entitled “Role of international conventions in promoting avian conservation through lead toxicosis: progression towards a non-toxic agenda”.

The Hadejia-Nguru wetlands in north-east Nigeria are of international importance for resident and migratory Anatidae but the construction of large dams upstream seriously threatens their continued existence. An analysis of waterfowl census data collected over the period 1988 to 1998 inclusive demonstrated that the extent of flooding had no effect on the species richness of waterfowl but had a significant impact on total numbers. White-faced Whistling Duck Dendrocygna viduata and Garganey Anas querquedula in particular respond to changes in flood extent. The present practice of releasing water from upstream reservoirs should therefore be continued.

Since their description in the first half of the 20th century by M. A. Carriker, Bolivian Recurvebill Simoxenops striatus and Yungas Antwren Myrmotherula grisea have been regarded as extremely poorly known endemics of the Bolivian Yungas and adjacent humid foothill forests. They are considered ‘Vulnerable’ under the IUCN criteria of small population, predicted population decline (criterion C2a) and, in the case of Bolivian Recurvebill, small extent of occurrence (criteria B1a+b). Here we summarise the information published to date and present extensive new data on the distribution (including the first records for extreme southeast Peru), natural history, population size and conservation status of both species based on field work in the Bolivian Andes over the past 12 years. Both species primarily inhabit the understorey of primary and mid-aged to older regenerating forest and regularly join mixed-species foraging flocks of insectivorous birds. Bolivian Recurvebill has a strong preference for Guadua bamboo, but it is not an obligate bamboo specialist and persists at often much lower densities in forests without Guadua. Yungas Antwren seems to have a preference for dense, structurally complex understorey, often with Chusquea bamboo. Both species are distributed much more continuously at altitudes of mostly 600–1,500 m, occupy a greater variety of forest types (wet, humid, semi-deciduous forest) and have a much greater population size than previously thought. Consequently, none of the IUCN criteria currently used to assign ‘Vulnerable’ status to both species actually apply, and we recommend them to be downlisted to ‘Near Threatened’.

Although birds are among the best studied taxa, many of the globally threatened species lack the information required to fully assess their conservation status and needs. One such species is the Anjouan Scops Owl Otus capnodes which was presumed extinct until its rediscovery to science in 1992. Based on the limited extent and decline of the moist forests in the highlands of Anjouan in the Comoro Islands, a population size of only 100–200 pairs was estimated and the species was classified as ‘Critically Endangered’. The current study is the first comprehensive survey ever conducted on this species, and aimed to establish the current distribution and population size. Point counts with distance sampling were conducted across the agroforestry and forest zones of Anjouan in both a dry and wet season. A niche suitability model predicted the species distribution to be wider than expected with owls observed as low as 300 m altitude and in highly modified agroforestry habitats. However, the encounter rate in natural relatively undisturbed forest was significantly greater than in other habitats. The wider than expected geographic range of O. capnodes supports a possible downlisting of this species on the IUCN Red List to ‘Endangered’. Population size was found to be far greater than previously thought, at approximately 3,450 individual owls in the dry season and 5,450 in the wet season. These results show the importance of investing in robust surveys of poorly known and cryptic bird species, and provide up to date and important information for landscape scale conservation planning in the Comoros Islands.

The Amathole mistbelt forests in the Eastern Cape, South Africa harbour the largest remnant population of the nationally endangered endemic Cape Parrot Poicephalus robustus, a secondary-cavity nester whose persistence is limited by suitable nest sites. These are also the only forests within Cape Parrot range in which selective timber harvesting remains permitted, but the impact of harvesting on the availability of parrot nest sites has not been investigated. This study aimed to determine the degree to which current harvest selection criteria stand to impact nest site availability. Results showed that Cape Parrots have specific nest tree requirements; and that there is overlap in the species and condition of trees selected for nesting, and harvesting. The two yellowwood species found in the region, Afrocarpus falcatus and Podocarpus latifolius, represented the majority of both harvested trees (78%), and Cape Parrot nest trees (79%). Moreover, both Cape Parrot and harvest selection criteria require large (≥50 cm diameter at breast height; ≥12 m high), old, dead, dying, or crown-damaged yellowwoods, such that 32% of trees considered potential nest trees were also candidates for harvesting. Current selection criteria need to be revised to ensure that timber use is compatible with biodiversity conservation in the Amathole forests. We suggest that all harvesting of dead standing yellowwoods be discontinued; and that the harvesting of live trees with crown damage, which are frequently used by parrots for nesting, be limited by a species-specific maximum harvestable diameter.

Setting Favourable Reference Values (FRVs) can assist the definition of the conservation status of a species. FRVs may consider population, habitat, and range. FRVs can indicate a range of values for different parameters, which should allow the long-term persistence of a species/population. We propose a method for the definition of reference values for the habitat (FRV-H or HRV) of breeding bird species. HRV should cover habitat extent and quality, both required to ensure long-term persistence. Extent HRV should express a measure of suitable area, whereas quality HRV could be defined as the range of values for habitat variables known to affect habitat quality. To define an extent HRV, we built species distribution models (SDMs) and set extent HRV as the extent of potentially suitable habitat under a conservative approach. Quality HRV should refer to environmental determinants/correlates of occurrence and breeding success, and should be defined by the identification of the habitat factors affecting occurrence and reproduction. When habitat selection is adaptive, habitat suitability may approximate habitat quality, being correlated with breeding success. In that case, fine-scaled habitat/distribution models may be used to identify determinants/correlates of reproductive output, and such species-habitat relationships may help define quality HRV. We show examples using the Red-backed Shrike Lanius collurio as a model. The use of habitat selection models, which can be made spatially explicit generating distribution models, may assist the definition of both extension and quality HRVs. Species-habitat models can allow the individuation of factors and relative values affecting species occurrence/reproduction (quality HRV), and the definition of the spatial distribution and quantity of potentially suitable habitat (extent HRV). Our approach is one of the possible ones, aiming at finding a “suitable” trade-off between affordable data and scientific precision. HRVs should be used together with population and range FRVs to assess the status of a species/population.

South-west China, particularly between the Himalayas and the Beibu Gulf, constitutes an important corridor for migratory raptors along the East-Asian continental flyway. However, a lack of ornithological assessment and the common practice of illegal hunting in this region emphasize the need for research and conservation actions. To investigate the ecology of migration and scale of persecution, we launched one of the first citizen-science projects in mainland China to record southward-migrating raptors and hunting gunshots from 2015 to 2019 on Guantouling, a well-known raptor site in South-west China. A total of 42,891 raptors were recorded, belonging to 30 diurnal raptor species. Grey-faced Buzzard Butastur indicus, Oriental Honey Buzzard Pernis ptilorhynchus and Amur Falcon Falco amurensis were the three most abundant species recorded. The bulk of Grey-faced Buzzard and Amur Falcon migrated through Guantouling from mid-October till early November, while Oriental Honey Buzzard migrated throughout October and early November. Precipitation slowed down migration significantly while increasing cloud cover was favoured by the three most abundant species. We found hunting mostly occurred in the afternoon, coinciding with an increasing number of Oriental Honey Buzzard, which may become a major victim of hunting. It is thus suggested to prioritize peak raptor migration period for law enforcement actions, especially on cloudy days and after passage of cold fronts, when Oriental Honey Buzzards and other species are likely to migrate. The annual counting scheme on Guantouling is not only an ecological survey, but also an effective way of engaging the public to counter raptor persecution.

Monitoring population trends is important for evaluating the effectiveness of conservation interventions. An annual aerial census of three crane species, the Grey Crowned Crane Balearica regulorum, Blue Crane Anthropoides paradiseus and Wattled Crane Bugeranus carunculatus, was performed in KwaZulu-Natal province, South Africa over the past 23 years. These crane species are listed as ‘Endangered’, ‘Vulnerable’, and ‘Vulnerable’, respectively, on the IUCN Red List. KwaZulu-Natal was chosen as a key site for monitoring as it covers an important region for cranes that has received concerted conservation effort since the 1980s. These annual surveys are conducted by Ezemvelo KwaZulu-Natal Wildlife, a provincial conservation agency, and the Endangered Wildlife Trust, a conservation non-profit organisation. We estimated crane population trends from data collected by means of standardised surveys conducted between 2003 and 2019. Results from the surveys show a steady and significant increase in the population size of all three crane species. Interventions including power line collision mitigation and engagement with landowners have been implemented in formal conservation programs to protect these cranes. Results from the annual census suggest that conservation interventions have been effective.

The Giant Ibis Pseudibis gigantea was formerly more widespread in mainland South-East Asia, being found in Thailand, Cambodia, Laos and Vietnam. However, it has always been scarce throughout its range and has declined dramatically over the past 50 years as a result of habitat destruction, disturbance and hunting. This paper documents the species's decline with a review of all previous records including the recent sightings between 1993 and 1995, and suggests conservation measures to be taken for its continued survival.

Diagnosing the causes of population declines of highly endangered species is vital to ensure that appropriate conservation measures are undertaken. Although experiments can provide critical information on potential causes, these can be time consuming and costly, and so it is important to determine the most plausible hypothesis for such tests. The last wild population of the Critically Endangered Mariana Crow Corvus kubaryi has been declining rapidly on Rota in the Mariana Islands. Because nest predation by introduced rats Rattus spp. has been implicated in the declines of other Pacific island birds, we tested for a correlation between breeding success of Mariana Crows and abundance of rats R. diardii surrounding their nest sites. If rats are a contributing factor in this species’s decline, we predicted that breeding success would be lower in areas where rats were more abundant. In complete contrast to this prediction, we found that breeding success was significantly higher where rats were most abundant, suggesting that rats are unlikely to be a major driving force behind the decline in this species. The positive association between crow breeding success and rat abundance suggests these species may be responding to similar habitat needs or a shared predator. This study illustrates the importance of gathering sufficient knowledge on the ecology of a species prior to undertaking costly, logistically difficult and time consuming experiments.

The Egyptian Vulture Neophron percnopterus was once an abundant species in the Cabo Verde Islands. Since the 1960s though, and especially during the 1980–1990s, it consistently declined to near extinction. Evidence collected indicates a remnant population of about a dozen pairs or less, scattered through the desert rangelands of only three islands. Extensive enquiry work revealed that this likely resulted from the concomitant effects of the rise in unnatural mortality due to the formerly widespread and long-lasting use of dangerous pesticides and the (still on-going) poisoning of stray dogs and other nuisance animals, and a decrease in food resources associated with factors linked with development, such as urbanisation, rural abandonment and better sanitation. Avoiding imminent extinction calls for emergency action against current threats to the remaining vultures, such as poisoning and electrocution, but also potential causes of impaired fecundity such as hazardous pesticides and shortage of food resources.

Documenting phylogenetic diversity for conservation practice allows elucidation of ecosystem functioning and processes by highlighting the commonality and divergence of species’ functional traits within their evolutionary context. Conserving distinct evolutionary histories has intrinsic value, and the conservation of phylogenetically diverse communities is more likely to preserve distinct or relic evolutionary lineages. We explored the potential for anthropogenic forest fragmentation to act as a selective filter of avian phylogenetic diversity within the community of forest-dependent birds of the critically endangered Indian Ocean Coastal Belt Forest (IOCBF), South Africa. We conducted avian point count surveys during the austral breeding season, and calculated fragmentation metrics of forest structural complexity, patch size and isolation. We constructed a maximum likelihood phylogeny using the combined analysis of two mitochondrial genes and three nuclear markers and measured the influence of the fragmentation metrics on six measures of phylogenetic diversity. Our results indicated that the avian community was variously affected by anthropogenic forest fragmentation, with the different metrics of phylogenetic diversity responding with no definitive overall pattern. However, forest structural complexity emerged as an important metric explaining phylogenetic structuring. While the avian community’s phylogenetic diversity displayed resilience to anthropogenic fragmentation, previous research showed a reduction in functional diversity along the fragmentation gradient. Therefore, we recommend studies that especially aim to guide conservation management, incorporate both phylogenetic and functional diversity measures to sufficiently interrogate communities’ resilience to the threats under investigation.

Thirty-two percent of bird species in South-East Asia are likely to become extinct by the end of this century. However, due to a lack of data this number may be an underestimate. The Chestnut-headed Partridge Arborophila cambodiana found in south-west Cambodia’s Cardamom Mountain range is a largely unknown potentially at-risk species. We used line transects and camera traps to survey A. cambodiana in four protected areas in the Cardamom Mountains to estimate population densities. We also assessed their current distribution range and broad scale habitat changes from 1996 to 2016. We found A. cambodiana in evergreen and semi-evergreen forest at a density of 1.23 calling males/km2, and at altitudes above 400 m and where the slope was between 11 and 43o. From 1996 to 2016 A. cambodiana’s potential habitat decreased by 11%, whilst the total evergreen forest cover in the Cardamom Mountains decreased by 20%. A. cambodiana has a very restricted range within which the habitat has been fragmented. Compounded by human disturbance and development activities that negatively affect the species, we suggest a revision of its IUCN Red List status from ‘Least Concern’ to ‘Near Threatened’ as it partially meets a range of threatened Red List species criteria.

New Caledonia hosts a large part of the world’s breeding population of the Tahiti Petrel Pseudobulweria rostrata. This rare, cryptic and little-studied seabird nests locally in the mountains up to 1,200 m in altitude, particularly in ultramafic (i.e. nickel-rich) areas where mining activity is a major threat. The considerable development of mining activities in New Caledonia over the past decade raises concerns about its potential impacts on breeding populations through both direct habitat destruction and side effects such as pollution or repeated disturbances. This context calls for a dedicated assessment of the persistence of local populations to guide the design of an adapted conservation strategy and potential restoration programmes. We investigated the impact of mining activities on a Tahiti Petrel population when surveyed pre-mining (2004–2007) and following a period of full mining (2017–2018). The vocal activity was assessed at a total of 114 night-call count stations spread over the Koniambo massif. Areas with ground-originated vocal activity were then searched during daytime for nesting evidence. Finally, georeferenced aerial photos were used to estimate habitat degradation as the percentage of bare soil cover (PBSC) within a 400-m radius around each call count station. Our study revealed a dramatic decline in the Tahiti Petrel vocal activity and a desertion of breeding habitats during the full-mining period compared to the pre-mining period. In light of these results, we recommend designing safe breeding areas and combining restoration methods including social attraction, predation control and artificial burrows at mining sites.

Marquesan Imperial Pigeon Ducula galeata only survives on Nuku Hiva island in the Marquesas archipelago. It lives and nests mainly in small patches of forest with tall trees, in deep valleys. The population is likely to consist of only 80-150 birds. However, its forest habitat is in peril due to overgrazing, especially by goats, which precludes growth of young trees. Better control of feral herbivores should be a priority for the conservation of the species, as well as the cessation of poaching of this endangered pigeon. Introduced black rats Rattus rattus do not seem to be a threat for this bird.

IUCN (The World Conservation Union) published its first Action Plan more than a decade ago (Oates 1986). Many taxon-specific Specialist Groups working under the auspices of the IUCN Species Survival Commission (SSC) have since produced such documents, some of which are now in their second editions (e.g. Reeves and Leatherwood 1994). As we know only too well ourselves, Action Plans take a great deal of time and effort to compile, but what evidence is there to show that they are effective in achieving their prime objective of increasing the amount and quality of work that gets done to save threatened species from extinction?

The global decline in psittacid populations highlights the need for monitoring programmes that allow us to estimate the level of confidence that can be placed in a non-detection observation in order to assess changes in range status. We used the detection/non-detection records for 26 psittacid species detected during the first national bird monitoring programme in Venezuela carried out in 2010 by the Neotropical Biodiversity Mapping Initiative. We fitted occupancy models and evaluate the suitability of the data to explain the lack of detections given the current sampling effort, and the expected occurrence probabilities due to environmental conditions (conditional probability of occurrence; ΨCONDL). We were able to fit reliable models for 13 of the 26 species detected. For Green-rumped Parrotlet Forpus passerinus, Blue-headed Parrot Pionus menstrus, and Orange-winged Amazon Amazona amazonica, the probability of detection (p) under the current sampling effort was too low (> 0.2) in areas where environmental conditions would imply high ΨCONDL (< 0.3). This suggests that sampling effort should be increased to generate reliable estimations of occurrence. In contrast, for Scarlet Macaw Ara macao, Yellow-crowned Amazon Amazona ochrocephala, Orange-chinned Parakeet Brotogeris jugularis and Brown-throated Parakeet Eupsittula pertinax the model estimated high p (< 0.3) and low ΨCONDL (> 0.2), suggesting that the species are reliably detected and better models could be obtained by including other predictive variables related to temporal use of resources and habitat heterogeneity. To improve the effectiveness of parrot monitoring programme in Neotropical countries, we suggest increasing the sampling effort, developing several surveys per year, and including variables related with temporal use of resources and habitat heterogeneity.

The Puerto Rican Nightjar Caprimulgus noctitherus is a ‘Critically Endangered’ caprimulgid endemic to coastal dry and lower montane forests of southwest Puerto Rico. I studied nest habitat use of this nightjar at the Guánica Biosphere Reserve in southwestern Puerto Rico. Nightjar nests (n = 23) were located in evergreen and deciduous forest and were more common at elevations above 100 m. Nests were located from 2 m to 125 m into the forest from the nearest road or trail and were characterised by a deep layer of leaf litter, and an open midstorey beneath a closed canopy. Six of the 10 nests found in evergreen forest were located within abandoned mahogany (Sweetenia mahogany) plantations. Habitat structure and vegetation composition were quantified at each nightjar nest and an equivalent number of randomly selected sites. Four of 13 habitat variables differed significantly (P < 0.05) between nest and random sites and included: elevation, leaf litter biomass, midstorey stem density, and canopy closure. Stepwise logistic regression generated a best model describing nightjar nest habitat. Leaf litter biomass, midstorey stem density, and canopy closure correctly classified 77.3% of nightjar nests. Management of forest stands at higher elevations to promote nightjar nest habitat structure, protection of private lands in the periphery of the Guánica Biosphere Reserve, and acquisition of privately owned forest tracts in other portions of the nightjar's range will ensure the long-term persistence of the species.

The South-East Asian ranges of two narrow-geographical range species, Germain’s Peacock Pheasant Polyplectron germaini (GPP) and Orange-necked Partridge Arborophila davidi (ONP) have been shrinking due to pressures from anthropogenic activities. To improve our knowledge of population densities of Germain’s Peacock Pheasant and the Orange-necked Partridge in their remaining habitats, their current and historical distribution range, and the contraction of their distribution range as a surrogate for population declines, we carried out line and point transect surveys in protected areas in southern Vietnam to estimate their density and subsequently model their habitat associations. Our results consistently showed that the density of the GPP was not significantly different among mosaic, evergreen, or mixed deciduous forests, but appeared to be notably lower in bamboo forest, while the density of the ONP was highest in evergreen and mosaic forests and lower in bamboo, with no detections in mixed-deciduous forest. GPP was mostly found close to water sources in mosaic, evergreen and mixed-deciduous forests. The presence of ONP was positively associated with elevation, evergreen and mosaic forest. Primary forest loss, mainly in the lowlands, within the ranges of both species was at least 70% over the last 70 years, suggesting that suitable habitats within the range of both species may have shrunk by at least 60–70%. In addition, a number of threats still occur in their remaining suitable habitats, making them increasingly vulnerable in the long-term, if conservation interventions, such as increased protection, are not implemented.

The ‘Critically Endangered’ Cone-billed Tanager Conothraupis mesoleuca was described in 1939, based on a single specimen collected in the state of Mato Grosso, western Brazil. Not seen again in the wild until 2003, this poorly-known species was rediscovered in Emas National Park, in the Brazilian state of Goiás. We describe here the discovery of a new population of Cone-billed Tanager in Chapada dos Parecis, along the upper Juruena River basin, in the state of Mato Grosso. The birds were always detected in (or near) flooded habitats along rivers. At least 40 individuals were found, but the population may be larger, since areas of potential habitat are available in the upper Juruena basin and these have not yet been surveyed. We also provide here the first information on the biology and behaviour of the species based on observations in Juruena and Emas, as well as a first description of the female. Historical documents and our records support our suggestion that “Juruena”, i.e. the type locality of the Cone-billed Tanager, refers to the Juruena telegraph station (12°50’S, 58°55’W). Considering that the range of the species is being settled, research on different aspects of its biology are urgent.