Based on surveys during 2000–2012 and best available knowledge, we estimate the global population size of the Endangered Scaly-sided Merganser Mergus squamatus to be c.1,940 pairs (or c.4,660 birds prior to reproduction). In Russia, surveys identified the breeding range in the Sikhote-Alin mountain range and the area adjoining the lower Amur River. Particular effort was made to define the edge of the range. Breeding densities in the Sikhote-Alin were applied to un-surveyed rivers within the range to estimate overall numbers. The breeding range comprises c.7,800 km of 120 rivers: 6,800 km in Russia, 600 in China and 400 in DPR Korea. In Russia it comprises 88 rivers of both the western and eastern slopes of the Sikhote-Alin Range, and two small isolated areas, one in central Khabarovsk and the other in the Jewish Autonomous Oblast. All known and potential breeding areas were surveyed in China, where the breeding range comprises the western slope of the Changbai Mountains, and one isolated river system in the Lesser Xingan Mountains. Scaly-sided Mergansers are also assumed to breed on the eastern slope of the Changbai Mountains in DPR Korea. No recent surveys have been made there but numbers were estimated by applying densities from China to rivers with apparently suitable habitat. Detailed examination of past records suggests that an earlier claim of breeding Scaly-sided Mergansers on the Dep River was erroneous and we conclude that the breeding range never extended as far west as has been portrayed in most literature. The lack of comparable surveys previously precludes an assessment of change in population range or size, though it seems inevitable that habitat loss in China is likely to have resulted in some loss of range and numbers, particularly in Heilongjiang Province, in recent decades.

The Endangered Scaly-sided Merganser Mergus squamatus is amongst the most threatened of sea ducks (Mergini), with an estimated population of c.4,600 individuals based on a recent population estimate on the breeding areas in Primorye, Far East Russia, China and DPR Korea. For the first time, we present published and unpublished data on the wintering distribution in China and smaller numbers in Korea. We report 156 sightings during 2000–2011, together with 11 records of wintering sites using geolocation devices, from 16 provinces in China, with greatest concentrations in Jiangxi Province (97 reports from 18 sites). Both sources of data suggest some degree of winter site fidelity to fast-flowing clear water rivers 50–350 m wide, with riffles, islands or sand banks in hilly/mountainous areas with low levels of human disturbance. Surveys located a maximum of 370–770 birds, 8–17% of the estimated total population, confirming our poor knowledge of the species’ wintering distribution. There is an urgent need to define the wintering range of this species which is widely dispersed and nowhere abundant, but is threatened everywhere by dam construction, sand and gravel extraction, industrial and domestic pollution and fishing that threaten the integrity of the winter habitat. This also raises important conservation questions about how to protect such a species that is not highly concentrated and may require catchment scale nature conservation actions to effectively safeguard its current distribution.

Staging sites are vital for large-sized migratory cranes, which require high-protein food sources during migration. In this study, we used field surveys and faecal analysis to determine the migration patterns and dietary composition of the globally threatened Red-crowned Crane Grus japonensis population that migrates and stages at the Yellow River Delta Nature Reserve (YRDNR), Eastern China. Analysis of 135 faecal samples collected during the migration season in 2008, 2010 and 2011 showed that 78.8% of the faeces comprised > 90% dry mass of tidal mudflat crab Helice tientsinensis remains, suggesting that tidal mudflat crab was an important source of food for these Red-crowned Cranes. Smaller percentages of two other crab species (Eriocheir sinensis, Macrophthalmus dilatatum), fish remains, ragworms Hediste diversicolor and vegetation were also detected in the faecal samples. Consumption of tidal mudflat crabs was found to increase from autumn through to spring. Surveys of tidal mudflat crabs from YRDNR revealed that female crabs have significantly smaller body size (dry mass) but higher energy reserve ratio (ash-free dry mass per body mass) compared to males. Red-crowned Cranes fed predominantly on small and medium-sized female crabs, with a female to male ratio of 5:1 in the diet, compared with the 1:2 ratio of female to male crabs found within the coastal wetland crab population. Our findings suggest that tidal mudflat crabs represent a critical food source for the migratory Red-crowned Crane population in YRDNR, and future crane conservation strategies should encompass the necessary measures to conserve the tidal mudflat crab population at this staging site.

A census of the Critically Endangered Bengal Florican Houbaropsis bengalensis was conducted between March and May 2012 on and surrounding the Tonle Sap floodplain in Cambodia, which supports the last extant population of the Indochinese subspecies blandini. We found a decline in the number of displaying males of 44–64% since a comparable estimate from the same sites in 2005 to 2007. The estimated population, including five individuals at one previously unsurveyed site, is now 216 (95% CI 156–275) displaying males, plus potential non-displaying males and an unknown number of females. If numbers continue to be lost at a similar rate, it is possible that blandini would become extinct within 10 years. Although the population faces multiple threats, this critical situation has primarily been caused by the recent, rapid conversion of the florican’s grassland habitat to intensive, industrial-scale, irrigated rice cultivation. To protect the Bengal Florican from extinction in South East Asia, existing Bengal Florican Conservation Areas (BFCAs) need expansion and improvements, including strengthened legal status by prime ministerial sub-decree and better demarcation, patrolling and management. As priorities, both irrigated rice and scrub encroachment within the BFCAs needs to be reversed, local communities better supported, and land outside the BFCAs monitored and strategically managed for florican conservation. Where possible, further BFCAs need to be established. Land purchase may also be an effective conservation measure; leasing land earmarked for cultivation would be cheaper, but less secure.

We studied foraging habitat selection by Lesser Kestrel Falco naumanni throughout the breeding period in south-west Spain by means of transects on which foraging observations were recorded. We focused on the effects of habitat and crop type, but also on the effect of vegetation structure and the presence of agricultural activities in the field on Lesser Kestrel use. We considered both the accumulated use of the foraging area during the breeding season and the instantaneous foraging habitat selection by kestrels. Foraging habitat selection was highly dynamic following crop development and agricultural activities. Almost all major arable crop types showed positive selection during some part of the breeding cycle. Accumulated use by kestrels demonstrated positive associations with wheat and cotton fields and negative selection of permanent habitat types, such as forested areas, woody crops and built-up areas that have no prey or are not used by the species due to unfavourable structure. Vegetation structure appears to play a major role in instantaneous foraging selection. Lesser Kestrels select fields with short vegetation and intermediate cover. They also forage on field margins and where agricultural activities such as ploughing or harvesting that facilitate access to prey are being conducted. Our results help to clarify apparent controversies among previous studies on the subject, highlighting the importance of the heterogeneity of agricultural landscapes around colonies (crops at different growth stages which provide variable vegetation height and cover during the breeding cycle) and the effect that agricultural activities have on facilitating access to prey. Beyond the species-specific approach, our work encourages further studies on habitat selection by farmland birds to account not only for human-based categorisation of habitats (e.g. crop type) but also on objective measures such as vegetation height and cover that influence access to prey and better reflect the high dynamism of agricultural landscapes.

In developing countries, ‘land sparing’ may be more effective than ‘land sharing’ in partially mitigating the impacts of farming on bird species diversity. We examined the pattern of change in the global and local distribution of Hinde’s Babbler Turdoides hindei, a ‘Vulnerable’ Kenyan endemic whose local abundance is dependent on a passive form of land sharing, in which farmland is left fallow or abandoned, enabling Lantana scrub to colonise. In 2011 we assessed the species’ global range and resurveyed three IBAs, surveyed previously in 2000–2001, to determine whether fine-scale changes in abundance reflected temporal changes in habitat quality. Although the babbler’s known range increased between 1900–1970 and 1991–2011, we suggest that this apparent expansion largely reflects an improved knowledge base, and that several recently discovered sites are likely to have been overlooked in the past. In combination, the three IBAs surveyed in 2000-2001 and 2011 showed little net change in the number of individuals (+1.3%) or groups (-3.8%) encountered, despite a 68% decline in the number individuals recorded at one site. Within 1-km transect sections there was a positive correlation between change in Hinde’s Babbler abundance and change in the amount of scrub cover available, such that a reduction in scrub cover of 22 and 6 percentage points, respectively, was associated with the loss of one group or one individual. The availability of scrub cover was dependent mainly on the amount land left uncultivated, perhaps in response to changes in the value of coffee and other crops. Since the babbler’s abundance thus currently depends mainly on land sharing by default, rather than by design, we suggest that a more proactive approach, involving land purchase or payments for land set aside, might help to secure its future.

Lear’s Macaw Anodorhynchus leari is currently listed as “Endangered” by IUCN. Although it only breeds on cliffs at two protected sites in Bahia State, Brazil, there is no accurate information on population parameters such as the number of breeding pairs and their breeding performance. Between 2009 and 2010, we sought to quantify, for the first time, breeding population size and the main breeding parameters for the species in the two known breeding sites, by quantifying the number of active nests and monitoring 75 breeding attempts. Overall, 80% of the breeding attempts were successful with 1.33 (± 0.86 SD) fledglings/breeding attempt (productivity) and 1.67 (± 0.60 SD) fledglings/successful nest (brood size). Breeding success and productivity were higher in 2010, while brood size did not vary between years and breeding sites. By adding 73 estimated nests to the 41 nests monitored, 228 individuals were estimated to be reproductively active in 2010, representing c.20% of the population (1,125 individuals). Given that the species is confined to a single population, further population increases could provoke overcrowding and negative density-dependent effects if it does not expand geographically. Therefore, long-term population monitoring focusing on the fraction of the population that is actually breeding and its breeding performance, rather than solely on the whole population size, is important for a better understanding of the population dynamics and conservation of this species.

The Sahel in West Africa is a major wintering area for many western Palearctic migrants. The breeding populations of many of these have declined over the past 50 years. However, there have been few intensive field studies on migrant ecology in the Sahel and these were generally within a very restricted area. Consequently our knowledge of the distribution of species within this extensive area and the habitat associations of these species is limited. Understanding these habitat associations is essential for the effective conservation management of populations. We brought together a group of experts and consulted a wider group by email to assess the main Sahelian habitat types used by 68 African-Eurasian migrant bird species. Those species that showed strongest declines during 1970–1990 were associated with more open habitats than those newly declining during 1990–2000, when declining species were associated with habitats with more shrubs and trees. Populations of species that winter in the Sahel are generally stable or increasing now as rainfall has increased and is now near the long-term average for the Sahel. Those which use the Sahel only as a staging area are, in many cases, in rapid decline at present.

Condors and vultures comprise the only group of terrestrial vertebrates in the world that are obligate scavengers, and these species move widely to locate ephemeral, unpredictable, and patchily-distributed food resources. In this study, we used high-resolution GPS location data to quantify monthly home range size of the critically endangered California Condor Gymnogyps californianus throughout the annual cycle in California. We assessed whether individual-level characteristics (age, sex and breeding status) and factors related to endangered species recovery program efforts (rearing method, release site) were linked to variation in monthly home range size. We found that monthly home range size varied across the annual cycle, with the largest monthly home ranges observed during late summer and early fall (July–October), a pattern that may be linked to seasonal changes in thermals that facilitate movement. Monthly home ranges of adults were significantly larger than those of immatures, but males and females used monthly home ranges of similar size throughout the year and breeding adults did not differ from non-breeding adults in their average monthly home range size. Individuals from each of three release sites differed significantly in the size of their monthly home ranges, and no differences in monthly home range size were detected between condors reared under captive conditions relative to those reared in the wild. Our study provides an important foundation for understanding the movement ecology of the California Condor and it highlights the importance of seasonal variation in space use for effective conservation planning for this critically endangered species.

The island of Aguiguan is part of the Mariana archipelago and currently supports populations of four endemic species, including one endemic genus, Cleptornis. Bird population trends since 1982 were recently assessed on the neighbouring islands of Saipan, Tinian, and Rota indicating declines in some native species. Point-transect surveys were conducted in 2008 by the U.S. Fish and Wildlife Service to assess population densities and trends on Aguiguan. Densities for six of the nine native birds—White-throated Ground-dove Gallicolumba xanthonura, Collared Kingfisher Todiramphus chloris, Rufous Fantail Rhipidura rufifrons, Golden White-eye Cleptornis marchei, Bridled White-eye Zosterops conspicillatus and Micronesian Starling Aplonis opaca—and the non-native bird—Island Collared-dove Streptopelia bitorquata—were significantly greater in 2008 than in 1982. No differences in densities were detected among the surveys for Mariana Fruit-dove Ptilinopus roseicapilla, and Micronesian Myzomela Myzomela rubratra. Three federally and locally listed endangered birds—Nightingale Reed-warbler Acrocephalus luscinius, Mariana Swiftlet Collocalia bartschi, and Micronesian Megapode Megapodius laperous)—were either not detected during the point-transect counts, the surveys were not appropriate for the species, or the numbers of birds detected were too small to estimate densities. The factors behind the increasing trends for some species are unknown but may be related to increased forest cover on the island since 1982. With declining trends for some native species on neighbouring islands, the increasing and stable trends on Aguiguan is good news for forest bird populations in the region, as Aguiguan populations can help support conservation efforts on other islands in the archipelago.

The Near-threatened Orinoco Goose Neochen jubata is a poorly known South American sheldgoose with a declining population and range distribution. In this study, we surveyed the Orinoco Goose population along the middle reaches of the Rio Juruá, western Brazilian Amazonia, and its first-order tributaries. We quantified the seasonal abundance of geese, pinpointed their approximate breeding season, and examined their habitat associations and the potential effects of human activities on their abundance. Hunting by local villagers was also monitored to assess the offtake rate of this species. Orinoco Goose occurrence in the region was highly seasonal and restricted to the dry season. We estimated a mean dry-season encounter rate of 7.18 ± 2.45 adult individuals per 4-km section along this river. Immature individuals were seen along the river margins from August to December. The species showed a strong preference for sandy beaches and was primarily restricted to the main river channel, with few individuals occurring along tributaries. The encounter rate of this species was also significantly related to fluvial distance from the municipal urban centre and to the level of protection from hunting. Hunting of Orinoco Goose was reported in 12 of the 26 villages monitored. The seasonal appearance of the Orinoco Goose in the region indicates that this is a migratory population. Our study indicates that strict protection of the river margins, and sandy beaches in particular, along the main river channel is likely to be positive for the conservation of this species along the Rio Juruá. However, further knowledge of migration routes is critical for effective protection of both breeding and non-breeding populations.