The diet patterns and trophic relationships are poorly understood for most tropical owl species. We used stable isotopes of carbon (δ13C) and nitrogen (δ15N) in 24 feather samples of the rare, endemic, and ‘Near Threatened’ Bearded Screech-owl Megascops barbarus to determine the trophic level of their prey and evaluate whether diet patterns vary (1) among individuals, (2) spatially along the species's range in the highlands of Chiapas, Mexico, and (3) temporally during the short- and long-term. Our results indicated that there was diet variation among individuals during the period of feather growth and there was a high positive correlation between stable isotopes in body and rectrices. The stable isotopes showed significant temporal differences in δ15N signature values, but not in δ13C values, with no obviously interpretable temporal pattern. Spatially, values of δ13C and δ15N did not vary across all nine sampled locations. The observed lower δ13C values suggested that this owl lives in humid forests. More long-term studies and spatial dietary and prey analysis will be necessary to increase our understanding of how habitat conditions determine the distribution, abundance and quality of food for the Bearded Screech-owl.

The Rota White-eye, Zosterops rotensis, is a critically endangered species endemic to the island of Rota, in the Mariana Islands, western Micronesia. There has been a dramatic decline in both its population size and range over the past few decades. The population, estimated at approximately 1,000 individuals in 1999, is found exclusively in 300 ha of mature limestone forest, though nearby areas of mature limestone forest remain unoccupied. We compared the bird community, vegetation characteristics and foliage-invertebrate density in forest plot pairs with known high and low densities of Rota White-eyes. Discriminant function analysis suggested that certain vegetation characteristics were best at predicting whether a plot was high-density or low-density. High-density plots had more stems with 20–50 cm DBH, more foliage intercepts at 3–9 m, more epiphytes, greater total canopy cover and fewer overall plant species. This information is essential for the protection of the current habitat of the Rota White-eye and for future efforts in the protection and management of this species.

This paper documents the catastrophic decline of the ‘Critically Endangered’ Fatu Hiva Monarch Pomarea whitneyi since 2000 and presents population dynamics and conservation actions for the species between 2008 and 2017. The Fatu Hiva Monarch conservation programme has prevented the extinction of the species thus far. However, after an initial increase in the population size within the management area between 2008 and 2012, recruitment subsequently declined. Improvements in the method of trapping to control cats in 2016 and 2017 coincided with encouraging results in terms of juvenile monarch survival rates, although two adult birds disappeared during the same period. The initial hypothesis, that the population would recover once the main threat, black (or ship) rat Rates Rattus predation, was effectively controlled in the breeding territories, has not proved to be correct. An alternative hypothesis assumes that cat predation, mainly on young birds, is limiting monarch recovery. Control of feral cats has been undertaken since 2010, but the implementation of a new trapping method (leg-hold traps) combined with a significant increase in cat trapping effort, has coincided with an increase in the number of cats culled, as well as monarch post-fledging survival in 2016 and 2017. For the first time in the project, no mortality has been observed for monarch chicks, fledged juveniles or immature birds. If this alternative hypothesis holds, we would expect to recruit young birds into the monarch population in the next year or two. First, this will reduce the likelihood that the Fatu Hiva Monarch will become extinct and second, provide a source population to either repopulate the island following the eradication of rats and cats or to translocate birds to a rat and cat free island.

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.

The ‘Endangered’ Cape Vulture Gyps coprotheres has been monitored across its range for decades through disparate studies varying in geographical scope and length. Yet, no long-term, range-wide survey exists for the species. Coordinated monitoring across the range of the Cape Vulture would be logistically challenging but provide a holistic view of population dynamics in this long-lived species that forages across much of southern Africa. Here, we report breeding pair counts from seven colonies in the Cape Vulture’s north-eastern breeding region from 2010 to 2019. We used state-space models to assess population growth across time. Manutsa, Soutpansberg, and Nooitgedacht colonies increased significantly over the study period, with three other colonies having positive estimates of population growth, but 95% credible intervals overlapped zero. The smallest colony at Moletjie is declining toward extirpation; only one breeding pair remained in 2019. Our results suggest the north-eastern population has been stable or increasing since 2010 with our 2019 surveys counting 2,241 breeding pairs across all sites. Indeed, there is an 89% chance that the population across the colonies we monitored increased from 2010 to 2019. Coordinated, range-wide, full-cycle monitoring is needed to thoroughly assess conservation status and efficacy of conservation actions taken for this endangered species.

We report on what appear to be increasing predation events on nesting Thick-billed Parrots Rhychopsitta pachyrhyncha. Thick-billed Parrots are classified as ‘Endangered’ and their seasonal breeding range is restricted to increasingly fragmented and degraded high elevation mixed conifer forest habitat within the Sierra Madre Occidental region of north-western Mexico. Predation of established breeding pairs has recently contributed to the ongoing decline of Thick-billed Parrot populations by removing mature birds with high reproductive value, which has associated consequences for future recruitment. We observed increasing predation events on nesting Thick-billed Parrots by bobcats Lynx rufus accompanied by kittens throughout the 2018–2019 breeding seasons, and we speculate that recent reductions in bobcat habitat have pushed them into new ranges where they are supplementing their diet with nontraditional prey items.

We estimated detection, dispersion and density of 10 hornbill, one pheasant and nine diurnal raptor species at Bala forest, southern Thailand, throughout 2004. We conducted 620 1-h lookout watches over the forest canopy from 14 elevated locations along 13.1 km of paved road through Bala, during which we recorded all detections and movements of target species. For a further 619 h, we also recorded all in-forest detections of target species during excursions along and adjacent to the road. Our records covered all months of the year and hours of the day, enabling us to estimate seasonal and diurnal patterns of detection for each target species. We found significant seasonal and diurnal variation for all commoner species in rates of overall detection, visual versus aural detection, and vociferousness. We related most monthly variation to the timing of nesting and most hourly variation to aspects of the behavioural ecology of each species. We used three techniques to estimate dispersion and density for each species, two from lookouts based on our counts of individuals or breeding units per unit area observed, and one from spot maps of core breeding units within 500 m of the road. Differences in our estimates of density varied within and between species, but were mostly lowest for the mean number of individuals detected from lookouts and highest for the maximum of breeding units, whether from lookout detections or core area counts from spot maps. These ranges of densities and their variance indicate upper and lower estimates for each species, and the differences between them and other survey techniques were explicable partly by the behavioural ecology of each species or apparent changes in density. Our density estimates never exceeded the highest comparative estimates for target species or near relatives in other forest habitats, although few were available for diurnal raptors. We suggest that 1-h lookout watches over forest, where feasible, offer alternative and efficient estimates of detection, dispersion and density to conventional distance-sampling techniques conducted from within forest. They will achieve optimum accuracy when conducted during the most detectable periods for target species, particularly for obvious and sparsely dispersed bird species.

Previously known from two specimens, Kaempfer's Tody-tyrant Hemitriccus kaempferi is a globally threatened species endemic to the southern Brazil Atlantic Forest. The first field observations of this little-known taxon were made in the 1990s and our data therefore provide the first published information on its natural history, including breeding biology, behaviour and vocalizations, as well as a new locality. As very little information has appeared in the literature concerning the identification of this species, we present notes on its plumage and habits. Remarks concerning the species's conservation prospects and the importance of the remaining forest in the vicinity of the type-locality for other threatened bird species are made.

Many species of China's Galliformes live in forests and it is often difficult to assess populations of species in these habitats. Such assessments are becoming increasingly important because much of China's forest has been altered through logging and other forms of human activity. After describing and mapping habitat types, we assessed two commonly used methods for counting pheasants (transects and point counts at dawn) in the Xianshennongjia Mountains in the Three Gorges area of Hubei Province in east-central China. Four pheasant species were recorded: Golden Pheasant Chrysolophus pictus, Temminck's Tragopan Tragopan temmincki, Koklass Pucrasia macrolopha and Common (or Ring-necked) Pheasant Phasianus colchicus. Golden Pheasants were detected most often by calls heard during transects and Koklass were recorded mostly during point counts at dawn. Temminck's Tragopan was detected during transects (by sightings) and also by calls at dawn. The relatively few Common Pheasants that were detected were registered mainly during transects. Golden Pheasants were found at the lowest altitudes, closest to human habitation and both Temminck's Tragopan and Koklass lived in various forest types above this. Common Pheasant was found in meadows at higher altitudes. We conclude that the methods used can determine general habitat use, but that no one method is likely to prove sufficient to unravel the detailed pattern of habitat use across all four species. In particular, further study is required to assess the relative importance of different forest types to Golden Pheasant, Temminck's Tragopan and Koklass. It would appear that human impact on the forest has affected the distribution of the pheasant species. For example, Common Pheasant is now absent from low-lying areas and occurs at what appears to be an unusually high altitude in the study area.

Some observations on a pair of Siberian White Cranes Grus leucogeranus were made during 1986-1991 in the Kolyma lowlands, former U.S.S.R. Their nesting habitat and behaviour are described. The diet and food distribution of both adult and chick are discussed. Observations in 1989 and the apparent starvation of a chick in 1991 suggested that narrow (10-20 m wide) strips of floating turf bordering permafrost-formed ponds and lakes may be essential for birds feeding a chick. In 1,050 km2 of tundra there were only 25 km of suitable lakeshore and of this about 18 km were used by the family.

Observations of the Horned Curassow Pauxi unicomis in Amboro National Park, depto. Santa Cruz, Bolivia, allowed us to assess the status of a species whose habits in the wild were virtually unknown. Vocalizations, including call notes and the deep booming song, are described. Density was estimated by counting booming birds in the breeding season using a three-hide triangulation method. The study showed birds to be aggregated in one part of the study area. A nest of was found and the incubating female was observed for nine days: the individual incubated alone, left the nest at night, and returned at first light.

Observaciones de la Pava Copete de Piedra (Pava Crista Azul) Pauxi unicomis en el Parque Nacional Amboró, depto. Santa Cruz, Bolivia, nos permitió evaluar el estado de una especie cuyo comportamiento en el ambiente silvestre es prácticamente desconocido. Se describen vocalizaciones, que incluyen notas de llamada “call notes” y el profundo canto de estampida “deep booming song.” Se estimó la densidad de las aves por conteo de los sonidos de estampida “booming birds” durante la estacion reproductiva, usando un método de triangulación con tres puestos de observatión. Este estudio mostró que las aves se agregaban en una parte del área del estudio. Se encontró un nido de Pauxi unicomis y al hembra fue observada durante nueve dias durante la incubación; la hembra incubaba sóla, dejaba el nido por la noche y regresaba a las primeras horas del amanecer.

The Madagascar Red Owl, known from the eastern rainforest of central Madagascar by a few specimens collected in the nineteenth and early twentieth century and one sight record in 1973, was rediscovered in late July 1993 in north-eastern Madagascar. An adult bird, held in captivity for approximately one year, was located in the town of Andapa. According to the owner, the owl had been obtained south-west of Andapa, near the village of Antanamangotroka, in a forested area connected to the Réserve Spéciale d'Anjanaharibe-Sud, and at about 800 m above sea-level. This record expands the known geographic range of this species and provides the first documentation of its continued existence in over 20 years.

La Chouette de Soumagne, connue de la forêt pluviale orientale du Domaine du Centre de Madagascar à travers quelques spécimens collectés au 19ème siècle et début du 20ème siècle et d'aprés une observation en 1973, a été redécouverte à la fin du mois de juillet 1993 au nord-est de Madagascar. Un individu adulte, qui venait de passer plus d'un an en captivité, a été découvert dans la ville d'Andapa. D'après la personne qui détenait l'animal, la chouette avait été capturee au sud-ouest d'Andapa, pres du village d'Antanamangotroka, au sein d'une zone forestière connectée avec la Réserve Spéciale d'Anjanaharibe-Sud, à une altitude d'environ 800 m au-dessus du niveau de la mer. Cette nouvelle donnée constitue une expansion significative de l'aire de distribution de cette espèce et apporte la preuve de la survie de cette espèce endémique qui n'avait pas été observee depuis plus de 20 ans.

The Blue Swallow Hirundo atrocaerulea is a globally threatened species endemic to sub-Saharan Africa. The total population breeding south of the Limpopo River (i.e. in South Africa and Swaziland) probably numbers around 100 pairs. A significant proportion of these birds breed in Swaziland, but to date little has been published on this population. Suitable breeding habitat has been reduced significantly in the country in recent decades, due mostly to afforestation with exotic timber plantations, with urbanization playing a lesser role. In Swaziland, breeding sites are restricted to grasslands above 1,200 m, but mostly above 1,300 m. Timing of egg laying is bimodal indicating double brooding. The number of nests initiated in a season is weakly correlated with rainfall in preceding months. Nests were built predominantly in disused antbear Orycteropus afer burrows, with smaller numbers in natural sinkholes. Mean clutch size was 2.80, and 61% of eggs laid resulted in fledged offspring. Mean productivity was 1.30 fledglings per pair per nest attempt. These figures suggest that breeding success is not currently being reduced in Swaziland. The minimum total population currently thought to be breeding in Swaziland is 10 pairs, but this is based on intensive studies of only part of the suitable range. It is recommended that a complete survey be conducted covering the entire range of the species in Swaziland.

The pressures for land use change have led to an increasing isolation of habitat remnants throughout the world. The goal of this study was to estimate the population size and density of some endemic and threatened species in a nature reserve in the Cerrado biome. One hundred and thirty four point transects were undertaken at the Estação Ecológica de Itirapina (EEI), one of the last natural grassland savannah remnants in São Paulo state, in the south-east of Brazil between September and December 2006 and densities estimated for seven species (four endemic to the Cerrado, one near-endemic and two grassland specialists). Neither species reached the minimum viable population size of 500-5000 individuals. Four species, White-banded Tanager, White-rumped Tanager, Black-throated Saltator and Sharp-tailed Tyrant have populations ranging from 112 to 248 individuals, while the other species have a low population (< 60 individuals). The mean densities of Sharp-tailed Tyrant and Cock-tailed Tyrant in the EEI grassland showed similar values to those observed in larger areas of the Cerrado, which may indicate that the EEI grassland area is well conserved. In spite of the restricted size of the EEI, small areas can maintain some endemic and threatened bird populations, thus contributing to local biodiversity and the ecological processes in the region. The capacity of fragments of Cerrado (~ 2,000 ha) to maintain populations of endemic and threatened bird species is unlikely to be effective in the long term.

Information about population sizes, trends, and habitat use is key for species conservation and management. The Buff-breasted Sandpiper Calidris subruficollis (BBSA) is a long-distance migratory shorebird that breeds in the Arctic and migrates to south-eastern South America, wintering in the grasslands of southern Brazil, Uruguay, and Argentina. Most studies of Nearctic migratory species occur in the Northern Hemisphere, but monitoring these species at non-breeding areas is crucial for conservation during this phase of the annual cycle. Our first objective was to estimate trends of BBSA at four key areas in southern Brazil during the non-breeding season. We surveyed for BBSA and measured vegetation height in most years from 2008/09 to 2019/20. We used hierarchical distance sampling models in which BBSA abundance and density were modelled as a function of vegetation height and corrected for detectability. Next, we used on-the-ground surveys combined with satellite imagery and habitat classification models to estimate BBSA population size in 2019/20 at two major non-breeding areas. We found that abundance and density were negatively affected by increasing vegetation height. Abundance fluctuated five- to eight-fold over the study period, with peaks in the middle of the study (2014/15). We estimated the BBSA wintering population size as 1,201 (95% credible interval [CI]: 637–1,946) birds in Torotama Island and 2,232 (95% CI: 1,199–3,584) in Lagoa do Peixe National Park during the 2019/20 austral summer. Although no pronounced trend was detected, BBSA abundance fluctuated greatly from year to year. Our results demonstrate that only two of the four key areas hold high densities of BBSA and highlight the positive effect of short grass on BBSA numbers. Short-grass coastal habitats used by BBSA are strongly influenced by livestock grazing and climate, and are expected to shrink in size with future development and climatic changes.

The near-threatened Lilian’s Lovebird Agapornis lilianae is a small parrot endemic to the Zambezi basin in south-east Africa. The species has a fragmented distribution predominantly within mopane woodlands and is widely referred to as a mopane specialist. The harvesting of mopane trees for charcoal production and timber are having widespread impacts on this woodland habitat, raising concerns over its capacity to support biodiversity. This study aimed to understand the key drivers determining the occurrence of Lilian’s Lovebird in the mopane woodlands of Zambia, focusing particularly on aspects of woodland structure, including the size and density of trees. We used a MaxEnt species distribution model based on historical species occurrence data, to inform selection of 116 survey plots in the Luangwa, Luano and Zambezi valleys. Each plot was sampled for Lilian’s Lovebirds and woodland structure described. Occurrence of Lilian’s Lovebird was found to be positively associated with the size of mopane trees (both height and diameter at breast height) suggesting that large ‘cathedral’ mopane trees provide a key resource for the species and that conservation efforts should focus on the protection of sites containing large trees. No Lilian’s Lovebirds were recorded in areas where they previously occurred to the west of Lower Zambezi National Park, and there was an absence of ‘cathedral’ mopane habitat in this area.

The Giant Conebill Oreomanes fraseri is a specialist of high Andean Polylepis forest remnants. With the aid of radio-tracking and visual observations, the average 100% minimum convex polygon home range size of seven adult individuals was 7.15 ha. Range size decreased with increasing tree density, and for equal tree densities, it was larger in the study site with larger Polylepis fragments. Home ranges often comprised areas that were largely or entirely devoid of trees. Within home ranges, space use significantly varied with time of day, and this pattern tended to be largely consistent among days. Given the large extent of variation in size and structure already observed in this small sample of home ranges, we suggest that apart from the size, shape, structure and degree of isolation of the remaining forest patches, also their topographic location, and hence sun exposure, may be an important consideration when designing conservation strategies for Giant Conebill.

The Laysan Duck Anas laysanensis is a threatened species endemic to Laysan Island, Hawaü U.S.A., with a population that appears subject to severe fluctuation, although this may be attributable to different census methods. The most effective method used so far has been one that notes the ratio of marked to unmarked birds seen on censuses conducted at dusk around the central lake. In 1986 and 1987, weekly censuses were made from which population estimates were derived with the Lincoln—Petersen Index: the current population is approximately 500. The ducks were least visible during the nesting and moulting periods of spring and summer, and population estimates were significantly lower during that period in both 1986 and 1987. This phenomenon calls in doubt other estimates and probably accounts for the fluctuations noted in previous years. Thus careful attention should be given to potential problems in monitoring threatened species populations, because without a clear understanding of the ecology of the threatened species, population estimates could suggest inappropriate management measures.

Reducing the time that birds’ eggs are exposed during incubation in the wild is a management strategy with the potential to reduce nest predation rates, enhance breeding success and increase the population size of endangered species. We tested whether manipulation of clutches through artificial incubation of Lesser Elaenia Elaenia chiriquensis eggs and subsequent reintroduction of new-born nestlings to their original nest, and the use of adoptive parents, were efficient ways of increasing the population size of this species. We evaluated the financial cost and benefit of three different management strategies of artificial egg incubation with reintroduction of nestlings to the original nest. We searched for nests and manipulated eggs during the breeding seasons of 2009 and 2010 in a savanna reserve in central Brazil. Real eggs were replaced by artificial eggs and artificially incubated. The following breeding parameters were monitored: hatching rate, fledgling productivity, daily survival rate of nestlings and nest success. The effect of nest monitoring frequency (daily or every 3–4 days) on breeding parameters was also tested. Hatching rate was much higher amongst artificially incubated eggs than naturally incubated eggs. Artificially incubated clutches presented higher rates of fledgling production and apparent nest success than non-manipulated clutches. Clutch manipulation did not interfere with nestling daily survival rate. Daily monitoring did not have negative effects. The clutch manipulation methodology we used proved to be viable and is a potential tool for increasing population size.