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Additional file 1. Figure S1. Illustration outlining reverse migration simulation. Table S1. Summary of environmental conditions during outbound and inbound migration of Demoiselle crane. Table S2. Differences in wind support of time-shifted outbound migration from actual migration. Table S3. Differences in wind support of time-shifted inbound migration from actual migration. Table S4. Differences in thermal uplift of time-shifted outbound migration from actual migration. Table S5. Differences in thermal uplift of time-shifted inbound migration from actual migration. Figure S2. Hourly distribution of wind support (a) and thermal uplift (c) flight height (b) and number of in-flight fix (d) during outbound and inbound migration.

The population of the Yellow-breasted Bunting 'Emberiza aureola', a formerly widely distributed and abundant songbird of northern Eurasia, suffered a catastrophic decline and a strong range contraction between 1980 and 2013. There is evidence that the decline was driven by illegal trapping during migration, but potential contributions of other factors to the decline, such as land-use change, have not yet been evaluated. Before the effects of land-use change can be evaluated, a basic understanding of the ecological requirements of the species is needed. We therefore compared habitat use in ten remaining breeding regions across the range, from European Russia to Japan and the Russian Far East. We also assessed large-scale variation in habitat parameters across the breeding range. We found large variation in habitat use, within and between populations. Differences were related to the cover and height of trees and shrubs at Yellow-breasted Bunting territories. In many regions, Yellow-breasted Buntings occupied early successional stages, including anthropogenic habitats characterized by mowing, grazing, or fire regimes. We found that the probability of presence can be best predicted with the cover of shrubs, herbs, and grasses. Highest probabilities were found at shrub cover values of 40%–70%. Differences in habitat use along a longitudinal gradient were small, but we found strong differences across latitudes, possibly related to habitat availability. We conclude that the remaining Yellow-breasted Bunting populations are not limited to specific habitat types. Our results provide important baseline information to model the range-wide distribution of this critically endangered species and to guide targeted conservation measures., Finanziert über die DEAL-Vereinbarung mit Wiley 2019-2022

Additional file 1: Table S1. Summary table of Swan Geese (Anser cygnoides) fitted with solar-powered GPS/GSM telemetry devices.

Additional file 2: Figure S1. Eurasian Spoonbill ES06 migration route map. Figure S2. Eurasian Spoonbill ES07 migration route map. Figure S3. Eurasian Spoonbill ES08 migration route map.

Until recently, almost nothing was known about the migration routes, flyway structure and population status of the Mute Swan Cygnus olor in East Asia. Here, we use a combination of GPS telemetry data, collar resightings, published literature and expert advice to update existing knowledge of its summer and winter distribution in the region, and to provide a preliminary description of the swans’ migration and habitat use. Three flyway units were indicated for the Mute Swan in East Asia. The Eastern China-wintering unit includes swans summering along the lower Selenga River in Russia, in central Mongolia and Inner Mongolia in China, which winter on the coast of eastern China, where 403 swans were counted in 2014/15, but where less than 30 have been counted in very recent years. In the absence of better data, we conservatively estimate this Chinese-wintering group at 400 birds. Mute Swans in the Korean-wintering unit are individuals that winter along the Korean Peninsula and summer in Inner Mongolia (China) and the Amur region (on the border of China and Russia); they are poorly covered by the mid-winter waterbird counts in South Korea and we have no knowledge of numbers wintering in North Korea. Finally, mid-winter counts of the introduced and sedentary population of Mute Swans in Japan have amounted to c. 240 birds in the last five years. We therefore suspect that there are likely c. 1,000 Mute Swans in Far East Asia, but await improved coverage throughout the entire wintering grounds to provide a better population estimate, with the species confirmed as one of the poorer known of the migratory waterbirds in the region. A single GPS-tagged Mute Swan tracked successfully provided detailed information on its migration routes, timing of migration and habitat use (almost exclusively waterbodies) over four complete migration episodes. It summered at Dalai Lake, China, used three stopover sites (on the borders of Russia and North Korea, in North Korea, and Baicheng City in China) during spring and autumn migration, and showed site fidelity to summer, winter and stopover sites. Combined count data and GPS data suggested that Mute Swans mostly occur within protected areas throughout the year. However, further research is required to establish the true distribution and abundance of this small and scattered species within these three flyways in East Asia, as well as to confirm its population structure and migration routes.

Our ability to define the population status, migration routes and seasonal distribution of Bean Geese Anser fabalis throughout the annual cycle in East Asia is severely compromised by the presence of two subspecies (Eastern Taiga Bean Goose A. f. middendorffii and Eastern Tundra Bean Goose A. f. serrirostris), which are difficult to differentiate in the field. In this analysis, using tracking data from telemetry-tagged geese, count survey data and expert knowledge, we attempt to update existing knowledge of the ranges covered by both subspecies of Bean Goose in East Asia. We suggest that, in summer, the Eastern Tundra Bean Goose ranges from the Taimyr Peninsula in the west to the Anadyr River in the east. Taiga Bean Geese breed further south in the taiga zone, and results indicate that they occur in north-western Mongolia, Yakutia and the Kamchatka Peninsula during the summer months. The winter distribution of both subspecies extends through China, Japan and South Korea. Tracking data from 154 individuals revealed a major overlap in the migration routes of Tundra Bean Geese wintering in China, South Korea and Japan, but discrete flyways for Taiga Bean Geese wintering in different regions. Long-term ground surveys carried out in the wintering range showed that numbers of Bean Geese in China and South Korea have increased significantly, to number 253,100 and 88,300 individuals respectively, of which roughly 10% are considered to be Taiga Bean Geese, about which subspecies we need to know more. Numbers of Japanese-wintering Bean Geese are slowly rising, currently numbering c. 10,300 (c. 900 Tundra Bean Geese and c. 9,400 Taiga Bean Geese). On the basis of these national and flyway estimates, derived from counts over the last five years, we identify new key wintering sites for the species in East Asia. Distributional changes at sites in China showed that wintering Bean Geese (most likely of the Tundra form) have become more widespread and numerous in the Yangtze River floodplain since the early 2000s. We argue for future strengthening of international cooperation to continue tracking and monitoring of Bean Geese, to provide a sound scientific basis for the effective management and protection of the flyway populations of both Bean Goose subspecies throughout East Asia.

European populations of the Greylag Goose Anser anser have been studies for over 50 years, but those in the East Asian flyway are less well known. Here we describe the breeding and wintering distribution of Greylag Geese wintering in China, based on historical and newly-reported telemetry data (from 31 individuals contributing complete migrations), wintering waterbird surveys and expert knowledge. Historical records, and also the data presented here, indicate that Greylag Geese breeding in the north of the Xinjiang Uygur Autonomous Region, China, and in Mongolia east of 93°E, through Inner Mongolia to western parts of Heilongjiang Province, China, likely almost all winter east of 107°E in China (97% in the Yangtze River floodplain and 3% in the Yellow River floodplain). Annual mid-winter waterbird counts confirm that very few Greylag Geese winter in Japan and South Korea. Count data suggest that the Far East Asia Greylag population wintering in China currently numbers 30,000 individuals, a major increase compared to 3,263 counted in 2005. Historical records however indicate that the wintering distribution was far greater 30 years ago, and that Greylag Geese are now less common than previously in Guangdong, Guizhou, Hainan, Henan, Hunan, Anhui and Jiangsu Provinces, as the species has become more concentrated further north in the Yangtze and Yellow River floodplains. On the basis of count data from winters 2010/11–2019/20, we identified 21 current key wintering sites (holding ≥ 1% of the flyway population, i.e. 300 birds) in the Yangtze River floodplain and one in the Yellow River floodplain for this population. Increasing use of farmland in winter, as well as site protection and sympathetic local management of wintering sites may have contributed to recent increases in Greylag Goose abundance in the flyway. These results provide a more robust basis for assessing the current status of the Far East Asia Greylag Goose population and a guide to priorities for further internationally coordinated research of the species. The need to improve monitoring and habitat management for maintaining the increasing numbers wintering in China is also emphasiseduropean populations of the Greylag Goose Anser anser have been studies for over 50 years, but those in the East Asian flyway are less well known. Here we describe the breeding and wintering distribution of Greylag Geese wintering in China, based on historical and newly-reported telemetry data (from 31 individuals contributing complete migrations), wintering waterbird surveys and expert knowledge. Historical records, and also the data presented here, indicate that Greylag Geese breeding in the north of the Xinjiang Uygur Autonomous Region, China, and in Mongolia east of 93°E, through Inner Mongolia to western parts of Heilongjiang Province, China, likely almost all winter east of 107°E in China (97% in the Yangtze River floodplain and 3% in the Yellow River floodplain). Annual mid-winter waterbird counts confirm that very few Greylag Geese winter in Japan and South Korea. Count data suggest that the Far East Asia Greylag population wintering in China currently numbers 30,000 individuals, a major increase compared to 3,263 counted in 2005. Historical records however indicate that the wintering distribution was far greater 30 years ago, and that Greylag Geese are now less common than previously in Guangdong, Guizhou, Hainan, Henan, Hunan, Anhui and Jiangsu Provinces, as the species has become more concentrated further north in the Yangtze and Yellow River floodplains. On the basis of count data from winters 2010/11–2019/20, we identified 21 current key wintering sites (holding ≥ 1% of the flyway population, i.e. 300 birds) in the Yangtze River floodplain and one in the Yellow River floodplain for this population. Increasing use of farmland in winter, as well as site protection and sympathetic local management of wintering sites may have contributed to recent increases in Greylag Goose abundance in the flyway. These results provide a more robust basis for assessing the current status of the Far East Asia Greylag Goose population and a guide to priorities for further internationally coordinated research of the species. The need to improve monitoring and habitat management for maintaining the increasing numbers wintering in China is also emphasised.

The migration routes and migratory patterns of Whooper Swans Cygnus cygnus summering in western Mongolia have not previously been described and the status of East Asian population is currently uncertain. Here we therefore use a combination of satellite tracking data, sightings of colour-marked individuals, published literature and expert knowledge to determine their distribution and site-use more precisely. Results indicated that the swans’ summer distribution extended further than had previously been recorded, with three new wintering areas (in Xinjiang, Qinghai, Gansu and Beijing) identified for the species in China. The East Asian Whooper Swan population was estimated to number 57,690 individuals, generating a new 1% threshold of 577 birds for determining sites of international importance for the species in the region. Using count data from winters 2011/12–2018/19, we identified eight wintering sites of international importance for the species in China, six in South Korea and 14 in Japan. Annual variation in national count totals highlighted the need to improve survey effort in China. Individual swans showed considerable within-winter fidelity to their wintering sites, with limited exchange between wintering areas. Migration duration, stopover duration, the number of stopover sites and migration legs were significantly greater in spring than in autumn, whilst migration speed was slower in spring than in autumn. Assessment of the habitats frequented found seasonal variation in the proportion of time that the swans spent on arable crops, pasture, wetlands and open water. From their GPS locations, 46.9%, 25.5%, 35.3% and 0.0% of the tagged swans were in protected areas during the summer, autumn staging, winter and spring staging periods, respectively. Our results provide a basis for the conservation of Whooper Swans in East Asia and illustrate the need for improved monitoring and further research into their migration, particularly for informing the protection and management of the main stopover and wintering sites for the species in China.

Two of the most fundamental ecological questions about any species relate to where they occur and in what abundance. Here, we combine GPS telemetry data, survey data and expert knowledge for the first time to define two distinct flyways (the East Asian Continental and West Pacific flyways), migration routes and abundance for the Eastern population of Bewick’s Swan Cygnus columbianus bewickii. The Eastern population is the largest flyway population, supporting c. 77% of Bewick’s Swan numbers globally. GPS telemetry data showed that birds breeding in the Russian arctic from the Yamal Peninsula to c. 140°E (including the Lena and Yana Deltas), winter in the middle and lower reaches of the Yangtze River in China (which we label the “East Asian Continental flyway”). Bewick’s Swans breeding from the Indigirka River east to the Koluchin Bay winter in Japan, mostly in Niigata, Yamagata and Ishikawa Prefectures (the “West Pacific flyway”). There was no overlap in migration routes used by tagged individuals from the two flyways. Counts of Bewick’s Swans in the East Asian Continental flyway during the 21st century have shown wide between-year variations, reflecting incomplete coverage in earlier years. Bewick’s Swans in this flyway currently numbers c. 65,000 birds based on extensive wintering survey coverage, compared to c. 81,000 in the early 2000s, based on less complete coverage. Chinese-wintering swans now concentrate mainly (c. 80%) at Poyang Lake in Jiangxi Province and Hubei Lakes (mostly in Longgan Lake), compared to a more widespread distribution both within Poyang and throughout the Auhui Lakes in 2004 and 2005. In contrast, Bewick’s Swans of the West Pacific flyway now numbers c. 40,000, compared to just 542 in 1970. This population has shown no significant overall change since 2004, when it numbered c. 45,000 birds. Small numbers within this population probably also winter in South Korea. These results provide our first basic understanding of the winter distribution of Chinese- and Japanese-wintering Bewick’s Swans in relation to their breeding areas, confirming the need to coordinate future research and monitoring in the two flyways, as well as the need for more information on swans wintering in South Korea.

Additional file 2: Table S1. Summary table of Bar-headed Geese (Anser indicus) fitted with solar-powered GPS/GSM telemetry devices in the current analysis. Table S2. The location and duration of stopover sites in the Qinghai-Tibet Plateau used by tracked Bar-headed Geese (n = 17) during autumn migration in 2016 and 2018. Table S3. The location and duration of stopover sites in the Qinghai-Tibet Plateau used by tracked Bar-headed Geese (n = 8) during spring migration in 2019. Table S4. Conservation status of Bar-headed Geese stopovers in the Qinghai-Tibet Plateau during autumn and spring migration. Table S5. Parameter estimates (β), standard errors, p values, and 95% confidence limits from the highest-ranked model (Table 2) estimating habitat selection of Bar-headed Geese in stopovers within the Qinghai-Tibet Plateau during autumn migration. Table S6. Parameter estimates (β), standard errors, p values, and 95% confidence limits from the highest-ranked model (Table 2) estimating habitat selection of Bar-headed Geese in stopovers within the Qinghai-Tibet Plateau during spring migration.

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Additional file 1: Figure S1. Map showing the nature and extent of the two distinctive flyways of the Bar-headed Goose (Anser indicus) in Central Asia.