Stopover behavior of Red-eyed Vireos(Vireo olivaceus) during fall migration on the coast of the Yucatan Peninsula

Background: For migrating birds, stopover requires spending time and energy that otherwise could be allocated to flying. Thus, birds optimally refuel their subsequent migratory flight by reducing stopover duration or foraging activ-ity in food-rich environments. In coastal habitats, birds may forego refueling and take short stopovers irrespective of local food availability. Given the paucity of studies exploring how migrants adjust stopover behavior in response to temporal variation in food availability, especially in the Neotropics, we fixed radio tags to 51 Red-eyed Vireos(Vireo olivaceous) over two years at two sites on the coast of Mexico's Yucatan Peninsula.Methods: We applied VHF radio tags during the fall of 2016 and 2017, and tracked birds using automatic and manual receiving units. We estimated stopover duration and activity levels(one site only) for between six and fifteen birds,depending on site and year. We measured fruit availability weekly along the net lanes where we captured birds. We used a generalized linear model to estimate the relationships between stopover duration/activity level and fruit den-sity, bird body mass and year. We interpreted relationships for the model with the lowest AICc value.Results: We found that approximately half of the birds departed on the same day they were captured. For the birds that stayed longer, we could not discern whether they did so because they were light, or fruit density was high. On the other hand, lighter birds were more active than heavier birds but only in one of the two years.Conclusions: Given our results, it is unlikely that Red-eyed Vireos refuel along the Yucatan coast. However, they still likely need to recuperate from crossing the Gulf of Mexico, which may necessitate foraging more often if in poor body condition. If the birds then move inland then stopover should be thought of as a large-scale phenomenon, where habitats with different functions may be spread out over a broad landscape.

Habitat selection and food choice of White-naped Cranes(Grus vipio)at stopover sites based on satellite tracking and stable isotope analysis

By combining satellite tracking,land-cover extracted from Landsite 8 images,and the traditional stable isotope analysis,we studied the habitat selection and food preference of a vulnerable migratory waterbird,the Whitenaped Crane(Grus vipio),in one of its key stagging sites,the Shandian River Basin in the semi-arid northern China,to provide knowledge that is critical for its conservation in the Anthropocene.Our results showed that the White-naped Cranes used both uplands and natural wetlands in the stopover site.While the cranes used farmland and natural land cover equally as night-time roosting grounds,they spent most daytime foraging at farmlands.Despite the extensive usage of croplands as their foraging ground,the Bayesian mixing models based on stable isotopic analysis revealed that crop residues after harvesting,such as Maize(Zea mays)and Naked Oat(Avena chinensis),were only a small fraction of the White-naped Cranes’diet(~19%),and their diet composited mainly natural plants,such as Allium ledebourianum,Potentilla anserina,and P.tanacetifoli.Moreover,more than 20%of the total wetlands in the region were modelled as home range of the cranes.On contrast,less than 10%of croplands and about 1%of the unused uplands were identified as home range.In addition,the entire core habitats were located in natural wetlands.Our findings demonstrated the importance of natural wetlands for the survival of the threatened crane.However,the satellite-derived land cover data showed that croplands increased rapidly in the last decade in this area,at the expense of natural wetlands.With the sharp decrease of White-naped Crane population in China,the conservation of stopover sites becomes imperative.Based on our analysis,we recommend the following management actions:conserving adequate natural wetland area,regulating anthropogenic pressures such as the use of herbicides,expanding the duration and extent of current conservation regulations,establishing a comprehensive monitoring program,and initiating basin-scale ecological restoration,for effective conservation of this threatened species.These integrated conservation strategies for migratory waterbirds are necessary,considering the rapid land-cover changes and agricultural expansion that have been occurring in East Asian-Australasian Flyway,especially in the semi-arid temperate zone.

Migration departure strategies of shorebirds at a final pre-breeding stopover site

Background: Departure decisions and behaviors of migratory birds at stopover sites are expected to maximize fit?ness by trade?offs among avoiding predators, optimizing refueling(energy) capacity, and matching other life?history events. We predict that species with different body sizes and migratory destinations will exhibit different behaviors when departing from the same stopover site. We also predict that with strong time constraint at the final pre?breed?ing stopover site, departure decisions may be less sensitive to exogenous factors, such as wind condition, compared to other stopover or nonbreeding sites.Methods: We recorded migratory departures of four shorebird species, i.e. Eurasian Curlew(Numenius arquata), Bar?tailed Godwit(Limosa lapponica), Great Knot(Calidris tenuirostris), and Grey Plover(Pluvialis squatarola), at Yaluji?ang Estuary Wetlands in China, a final pre?breeding stopover site in the northern Yellow Sea, from 2011 to 2014. We compared flock sizes, departure time and departure directions between species, and investigated the effects of tide and weather conditions(rain and ground wind speed and direction) on the departure decision of shorebirds.Results: We found that larger species departed in smaller flocks and were more variable in daily departure time. Departure trajectory of all four species appeared to be influenced by coastal topography. With the east–west coast?line and intertidal mudflat on the south, birds exhibited westward or eastward deflection from the shortest migra?tory routes. Bar?tailed Godwit was the only species that deviated to the southeast and did not climb over the land. Birds avoided departure during precipitation, while their departure was not related to ground wind benefit or tidal condition.Conclusions: Body size among species, which influences their vulnerability to predators, might be important in shaping shorebird departure strategies. Diverse departure directions could be the result of different wind use tac?tics in climbing stage. Narrow optimal time window of breeding might lead to reduced flexibility in departure date at a final pre?breeding site. Both endogenous and exogenous are important in shaping departure behaviors and decisions.

The Influence of Tourists on Stopover City： A Case Study of Burqin City Influenced by Kanas Scenic Area in Xinjiang Uygur Autonomous Region in China

Researches of tourism impact usually pay more attention to tourism destination but less attention to the stopover city of tourists. This paper researched the economic impact of tourism destination development on stopover city, Burqin, the case study city, which is a county center of less developed region in northwest of China and is a stopover city for tourists going to Kanas scenic area. We analyzed the impacts on industrial structure and urbanization of Burqin city on the bases of local statistical data through the correlation analysis approach. Then, we analyzed the difference of income and expenditure of residents whose job was relative to tourism compared to those residents whose job was not relative to tourism. At last, 10 variables were chosen from relative documents using the 5-point Likert scale to measure the residents＇ perception of the economic influence of tourists at Burqin according to Fishbein model. Research showed that industrial structure, urbanization, residents＇ income and expenditure of Burqin have improved, and urban economy has also improved.

Perceptions of Beach Stewards and Information Needs for Shorebird Stopover Sites Vary as a Function of Visitor Interests: Improving Stewardship Programs in Coastal Landscapes

Many studies have demonstrated that some of the activities of people can disturb nesting and foraging birds, particularly along coasts and estuaries. Some managers respond to human disturbance of sensitive species by closing beaches, but most have stewards monitor and restrict access to beaches or portions of beaches. Yet little is known about the type of visitor or their perceptions of beach stewards. This paper explores the general acceptance of beach stewards and their role in conservation of red knots (Calidris canutus rufa), other shorebirds, and horseshoe crabs (Limulus polyphemus) along the Delaware Bay (New Jersey) beaches by interviewing 279 visitors during the stopover period. While most people came to see the shorebird and horseshoe crab spectacle (60%), many came for the scenery, tranquility, and recreation. Just over half of the people interviewed said that the stewards were helpful (58%), although most of those that answered this question later said that they provided conservation value (86%), but only 40% said they relied on the stewards for information. On a Likert rating scale of 1 to 5 (the highest value), the mean rating for whether it was important for stewards to be present was 3.87 ± 0.09, and the rating for the presence of stewards who can provide information was 3.71 ± 0.11. In contrast, protection of shorebirds was rated a mean of 4.79 ± 0.04. There were significant visitor type differences in how important stewards were, but not in the importance of stewards who can provide information. Fishermen, recreationists, and people coming for scenery and tranquility rated the presence of stewards higher than those visitors who were interested in either shorebirds or crabs (or both). Ratings also differed significantly as a function of age and gender;older adults and females rated characteristics higher than did people under 30 years and males. Information needs identified by stewards are also discussed. These data can be used by the managers developing a strategy for conservation of shorebirds and other species sensitive to disturbance, and for the implementation of an effective stewardship program.

Habitat selection of woodchat shrikes Lanius senator during spring stopover is related to foraging strategy

Every spring a huge number of passerines cross the Sahara Desert and the Mediterranean Sea on their way to their breeding grounds. Stopover sites after such extended barriers where birds can rest, refuel, and find shelter from adverse weather, are of crucial importance for the outcome of their migration. Stopover habitat selection used by migrating birds depends on landscape context, habitat patch characteristics, as well as on the particular energetic conditions and needs of individ- ual birds, but it is still poorly investigated. We focused on a long-distance migrating passerine, the woodchat shrike, in order to investigate for the first time the species＇ habitat selection at a spring stopover site （island of Antikythira, Greece） after the crossing of the Sahara Desert and Mediterranean Sea. We implemented radio-tracking, color-ringing, and visual behavioral observa- tions to collect data on microhabitat use. Generalized Linear Mixed Models were developed to identify the species＇ most preferred microhabitat during its stopover on this low human disturbed island. We found that high maquis vegetation surrounded by low vegetation was chosen as perches for hunting. Moreover, high maquis vegetation appeared to facilitate hunting attempts toward the ground, the most frequently observed foraging strategy. Finally, we discuss our find- ings in the context of conservation practices for the woodchat shrike and their stopover sites on Mediterranean islands.

Migration phenology determines niche use of East Asian buntings (Emberizidae)during stopover

Stopover niche utilization of birds during migration has not gained much attention so far,since the majority of the studies focuses on breeding or wintering areas.However,stopover sites are crucial for migratory birds.They are often used by a multitude of species,which could lead to increased competition.In this work,we investigated niche use of 8 migratory and closely related Emberiza bunting species at a stopover site in Far East Russia,situated on the poorly studied East Asian flyway.We used bird ringing data to evaluate morphological similarity as well as niche overlap on the trophic,spatial,and temporal dimension.Bill morphology was used as a proxy for their trophic niche.We were able to prove that a majority of the species occupies well-defined stopover niches on at least one of the dimensions.Niche breadth and niche overlap differ between spring and autumn season with higher overlap found during spring.Morphological differences are mostly related to overall size and wing pointedness.The temporal dimension is most important for segregation among the studied species.Furthermore,all species seem to exhibit a rather strict and consistent phenological pattern.Their occurrence at the study site is highly correlated with their geographic origin and the length of their migration route.We assume that buntings are able to use available resources opportunistically during stopover,while trying to follow a precise schedule in order to avoid competition and to ensure individual fitness.

Migration routes of the endangered Oriental Stork(Ciconia boyciana)from Xingkai Lake,China,and their repeatability as revealed by GPS tracking

The Oriental Stork(Ciconia boyciana)is listed as'Endangered'on the International Union for the Conservation of Nature(IUCN)Red List of Threatened Species and is classified as a first category nationally protected bird species in China.Understanding this species'seasonal movements and migration will facilitate effective conservation to promote its population.We tagged 27 Oriental Stork nestlings at Xingkai Lake on the Sanjiang Plain in Heilongjiang Province,China,used GPS tracking to follow them over the periods of 2014-2017 and 2019-2022,and confirmed their detailed migratory routes using the spatial analysis function of ArcGIS 10.7.We discovered four migration routes during autumn migration:one common long-distance migration route in which the storks migrated along the coastline of Bohai Bay to the middle and lower reaches of the Yangtze River for wintering,one short-distance migration route in which the storks wintered in Bohai Bay and two other migration routes in which the storks crossed the Bohai Strait around the Yellow River and wintered in South Korea.There were no significant differences in the number of migration days,residence days,migration distances,number of stopovers and average number of days spent at stopover sites between the autumn and spring migrations(P>0.05).However,the storks migrated significantly faster in spring than in autumn(P=0.03).The same individuals did not exhibit a high degree of repetition in their migration timing and route selection in either autumn or spring migration.Even storks from the same nest exhibited considerable between-individual variation in their migration routes.Some important stopover sites were identified,especially in the Bohai Rim Region and on the Songnen Plain,and we further explored the current conservation status at these two important sites.Overall,our results contribute to the understanding of the annual migration,dispersal and protection status of the endangered Oriental Stork and provide a scientific basis for conservation decisions and the development of action plans for this species.

Migration routes and differences in migration strategies of Whooper Swans between spring and autumn

Long-distance migratory birds travel more rapidly in spring than in autumn,as they face temporal breeding constraints.However,several species travel slower in spring owing to environmental influences,such as food availability and wind conditions.GPS trackers were attached to 17 Whooper Swans(Cygnus cygnus) inhabiting northeastern Mongolia,to determine their migration routes and stopover sites in spring and autumn.Differences between spring and autumn migrations,migration-influencing parameters,and the effect of spring stopover site temperatures were analyzed.Six swans completed perfect tours between their wintering and breeding sites,and these data were used for analysis.Spring migration lasted 57 days,with 49.2 days spent at 3.7 stopover sites.Autumn migration lasted 21.5 days,with 17.5 days spent at 1.0 stopover sites.Thus,the swans traveled more rapidly in autumn than in spring.Migration distance,number of stopovers,migration speed,and straightness were important migration determinants in both spring and autumn.Migration distance,stopover duration,number of stopovers,daily travel speed,travel duration,and migration speed differed significantly between spring and autumn.During spring migration,the temperature at the current stopover sites and that at the future stopover sites displayed significant variations(t=1585.8,df=631.6,p <0.001).These findings are critical for the conservation and management of Whooper Swans and their key habitats in East Asian regions,and the data are anticipated to make a particularly significant contribution toward developing detailed management plans for the conservation of their key habitats.

Spring migration duration exceeds that of autumn migration in Far East Asian Greater White-fronted Geese (Anser albifrons)

Background:Migration theory suggests,and some empirical studies show, that in order to compete for the best breeding sites and increase reproductive success,long-distance avian migrants tend to adopt a time minimization strategy during spring migration, resulting in shorter duration spring migration compared to that in autumn.Methods:Using GPS/GSM transmitters,we tracked the full migrations of 11 Greater White-fronted Geese (Anser albifrons) between southeast China and the Russian Arctic,to reveal the migration timing and routes of the East Asian population, and compare the difference in duration between spring and autumn migration of this population.Results:We found that migration in spring (79 ± 12 days) took more than twice as long to cover the same distance as in autumn (35 ±7 days).This difference in migration duration was mainly determined by significantly more time spent in spring (59±16 days) than in autumn (23± 6days) at significantly more stopover sites. Conclusions:We suggest that these geese, thought to be partial capital breeders, spent almost three quarters of total migration time at spring stopover sites to acquire energy stores for ultimate investment in reproduction, although we cannot reject the hypothesis that timing of the spring thaw also contributed to stopover duration.In autumn,they acquired necessary energy stores on the breeding grounds sufficient to reach Northeast China staging areas almost without stop, which reduced stopover times in autumn and resulted in the faster autumn migration than spring.

Seasonal and population differences in migration of Whimbrels in the East Asian–Australasian Flyway

Background:Conserving migratory birds is challenging due to their reliance on multiple distant sites at different stages of their annual life cycle.The concept of“flyway”,which refers to all areas covered by the breeding,nonbreeding,and migrating of birds,provides a framework for international cooperation for conservation.In the same flyway,however,the migratory activities of the same species can differ substantially between seasons and populations.Clarifying the seasonal and population differences in migration is helpful for understanding migration ecology and for identifying conservation gaps.Methods:Using satellite‑tracking we tracked the migration of Whimbrels(Numenius phaeopus variegatus)from nonbreeding sites at Moreton Bay(MB)and Roebuck Bay(RB)in Australia in the East Asian-Australasian Flyway.Mantel tests were used to analyze the strength of migration connectivity between the nonbreeding and breeding sites of MB and RB populations.Welch’s t test was used to compare the migration activities between the two populations and between northward and southward migration.Results:During northward migration,migration distance and duration were longer for the MB population than for the RB population.The distance and duration of the first leg flight during northward migration were longer for the MB population than for the RB population,suggesting that MB individuals deposited more fuel before departing from nonbreeding sites to support their longer nonstop flight.The RB population exhibited weaker migration connectivity(breeding sites dispersing over a range of 60 longitudes)than the MB population(breeding sites concentrating in a range of 5 longitudes in Far Eastern Russia).Compared with MB population,RB population was more dependent on the stopover sites in the Yellow Sea and the coastal regions in China,where tidal habitat has suffered dramatic loss.However,RB population increased while MB population decreased over the past decades,suggesting that loss of tidal habitat at stopover sites had less impact on the Whimbrel populations,which can use diverse habitat types.Different trends between the populations might be due to the different degrees of hunting pressure in their breeding grounds.Conclusions:This study highlights that conservation measures can be improved by understanding the full annual life cycle of movements of multiple populations of Whimbrels and probably other migratory birds.

Detecting the non-breeding region and migration route of Whimbrels(Numenius phaeopus rogachevae)in the East Asian–Australasian Flyway

Determining the migration routes and connections of migratory birds at the population level helps clarify intraspecific differences in migration.Five subspecies have been recognized in the Whimbrel(Numenius phaeopus)in Eurasia.Ssp.rogachevae is the most recently described subspecies.It breeds in Central Siberia,while its non-breeding region and migration routes are still unclear.We tracked the migration of Eurasian Whimbrels captured at three non-breeding sites(Moreton Bay in east coast of Australia,Roebuck Bay in Northwest Australia and Sungei Buloh Wetland in Singapore)and two migration stopover sites(Chongming Dongtan and Mai Po Wetland in China).We determined the breeding sites and inferred the subspecies of the tagged birds in the East Asian–Australasian Flyway(EAAF)based on the known breeding distribution of each subspecies.Of the 30 tagged birds,6 and 21 birds bred in the breeding range of ssp.rogachevae and variegatus,respectively;one bred in the presumed transition area between the breeding range of ssp.phaeopus and rogachevae,and two bred in the region between the breeding range of ssp.rogachevae and variegatus.The birds that bred in the ssp.rogachevae breeding range spent their non-breeding season in the northern Sumatra,Singapore,East Java and Northwest Australia and mainly stopped over along China's coasts during migration.None of our birds bred in the exclusive breeding range of the phaeopus subspecies.Previous studies have predicted that rogachevae whimbrels migrate along the Central Asian Flyway and spend the non-breeding season in West India and East Africa.We found that at least some rogachevae whimbrels migrate along the EAAF and spend the non-breeding season in Southeast Asia and Australia.The ssp.phaeopus is at best sparsely distributed in the EAAF in the west region,or possibly does not occur at all.

Coastal wetlands in Lianyungang,Jiangsu Province,China:probably the most important site globally for the Asian Dowitcher(Limnodromus semipalmatus)

Background:Despite an increasing number of surveys and a growing interest in birdwatching,the population and distribution of Asian Dowitcher(Limnodromus semipalmatus),a species endemic to the East Asian-Australasian and Central Asian Flyways,remains poorly understood,and published information about the species is largely outdated.In boreal spring 2019,over 22,432 Asian Dowitchers were recorded in a coastal wetland at Lianyungang,Jiangsu Prov-ince,China,constituting 97.5%of its estimated global population.Methods:In 2019 and 2020,we conducted field surveys at Lianyungang to determine the numbers of Asian Dow-itchers using the area during both southward and northward migrations.We also assessed the distribution and abun-dance of Asian Dowitchers elsewhere along the China coast by searching literature and consulting expert opinion.Results:The coastal wetlands of Lianyungang are the most important stopover site for Asian Dowitchers during both northward and southward migrations;they supported over 90%of the estimated global population during north-ward migration in two consecutive years(May 2019 and 2020).This area also supported at least 15.83%and 28.42%(or 30.74%and 53.51%using modelled estimates)of the global population during southward migration in 2019 and 2020 respectively.Coastal wetlands in the west and north of Bohai Bay also have been important stopover sites for the species since the 1990s.Although comprehensive,long-term monitoring data are lacking,available evidence sug-gests that the population of the species may have declined.Conclusions:The high concentration of Asian Dowitchers at Lianyungang during migration means the species is highly susceptible to human disturbances and natural stochastic events.The coastal wetlands of Lianyungang should be protected and potentially qualify for inclusion in China’s forthcoming nomination for World Heritage listing of Migratory Bird Sanctuaries along the Coast of Yellow Sea-Bohai Gulf of China(Phase II)in 2023.Additional research is needed to understand Asian Dowitchers’distribution and ecology,as well as why such a high proportion of their population rely on the Lianyungang coast.

Springtime migratory restlessness and departure orientation of Great Knots(Calidris tenuirostris)in the south compared to the north Yellow Sea

Background: The motivation of birds to proceed with migration is associated with both endogenous and exogenous factors. According to their migratory situation and to the characteristics of stopover sites, birds might exhibit migratory motivation differently among sites. Although migratory motivation of migrating birds has been well studied in many species, the investigation of the same species in different migratory situations and at different stopover sites is still limited. We predicted that birds at different stopover sites could differ in migratory disposition, including expression of migratory restlessness and responses to environmental cues.Methods: Here we compared migration motivation and orientation of Great Knots(Calidris tenuirostris) at two stopo ver sites, Chongming Dongtan in the south Yellow Sea, which is a temporary rest site, and Yalujiang Estuary Wetland in the north Yellow Sea, which is a critical refuelling site, during northward migration. Modified Emlen funnels, with thermal paper inside to record scratches of the birds, were used to detect activity(intensity and direction) of birds. Environmental conditions, including wind direction and speed, cloud cover, tide condition, times of the day(before and after sunset) were recorded during experiments. Generalized linear models were used to detect the effects of endogenous and exogenous factors on the migratory motivation of the birds.Results: In the south Yellow Sea, the migratory activity intensity of Great Knots was positively related to wind assistance. In the north Yellow Sea, where birds exhibited higher intensity of migratory activity than in the south, the intensity increased and the motivation to initiate migration grew stronger as the season advanced. The Great Knots exhibited wind-related orientation behaviour in the funnels at both sites.Conclusions: The results suggest that the intensity of migratory motivation differed between the two sites. Departure decisions of Great Knots appear to be affected mainly by external factors at the temporary rest site in the south Yellow Sea but possibly by endogenous factors at the final pre-breeding refuelling site in the north Yellow Sea.

Monitoring population dynamics of the migratory Red-crowned Crane (Grus japonensis) at Shuangtaihekou National Nature Reserve,northeastern China,from 1991 to 2012

We studied migratory Red-crowned cranes from 1991-2012 in order to track population dynamics and trends for these cranes over time at Shuangtaihekou,northeastern China.Our results show that the earliest arrival date of the Red-crowned Crane (Grus japonensis) was usually around 1 March in the spring and the latest departure date of the cranes around 8 November.The peak period for the number of cranes observed in the spring was 10-20 March over these 22 years.The staging period in the spring is about 25 days.Comparing the highest number of Red-crowned cranes observed in the spring,the migratory population was around 400 birds in the 1990s,then,increased to over 800 birds in 2000.For a short while,the population maintained itself around 600-800 birds.After that,the population started to decline,until during the most recent years,we observed around 400 birds at peak times of each season.Our results match a similar population change pattern observed in the wintering area for a western population,which has been declining since 2000.There is an urgent need to reinforce protection and management,as well as to maintain and improve the quality of their habitats.

Fuel load and flight ranges of blackcaps Sylvia atricapilla in northern Iberia during autumn and spring migrations

Fuel accumulation, mainly as fatty acids, is one of the main characteristics of migratory, birds. Studying to what extent each population or species manages fuel load and how it varies along routes of migration or between seasons （autumn and spring migrations） is crucial to our understanding of bird migration strategies. Our aim here was to analyse whether migratory blackcaps Sylvia atrieapilla passing through northern Iberia differ in their mean fuel loads, rate of fuel accumulation and ＇ potential＇ flight ranges between migration seasons. Blackcaps were mist netted for 4 h-periods beginning at dawn from 16 September to 15 November 2003 - 2005, and from 1 March to 30 April 2004 - 2006 in a European Atlantic hedgerow at Loza, northern Iberia. Both fuel load and fuel deposition rate （this latter assessed with difference in body mass of within-season recaptured individuals） were higher in autumn than in spring. Possible hypotheses explaining these results could be seasonal-associated variations in food availability （likely lower during spring than during autumn）, the fact that a fraction of the migrants captured in spring could breed close to the study area and different selective pressures for breeding and wintering

Seasonal and regional differences in migration patterns and conservation status of Swan Geese(Anser cygnoides)in the East Asian Flyway

Background:The Swan Goose(Anser cygnoides)breeds across Mongolia and adjacent China and Russia and winters exclusively in China.It is globally threatened,showing long-term major range contractions and declining abundance,linked to habitat loss and degradation.We remain ignorant about the biogeographical subpopulation structure of the species and potential differences in their migration timing,stopovers and schedules,information that could be vital to effective conservation of different elements of the species population,which we address here with results from a telemetry study.Methods:In 2017-2018,we attached GPS/GSM telemetry devices to 238 Swan Geese on moulting sites in three discrete parts of their summering area(Dauria International Protected Area,Central Mongolia and Western Mongolia),generating 104 complete spring and autumn migration episodes to compare migration speed and nature between birds of different summer provenances.Results:Birds from all three breeding areas used almost completely separate migration routes to winter sympatrically in the Yangtze River floodplain.Although many features of the spring and autumn migrations of the three groups were similar,despite the significantly longer migration routes taken by Western Mongolian tagged birds,birds from Dauria Region arrived significantly later in winter due to prolonged staging in coastal areas and took longer to reach their breeding areas in spring.Among birds of all breeding provenances,spring migration was approximately twice as fast as autumn migration.Areas used by staging Swan Geese(mainly wetlands)in autumn and spring almost never fell within national level protected areas,suggesting major site safeguard is necessary to protect these critical areas.Conclusions:This study showed the discreteness of migration routes taken by birds of different summer provenances and differences in their migratory patterns,highlighting key staging areas(Yalu River Estuary in China/North Korea for Dauria Region breeding birds,Daihai Lake for Central Mongolian and Ordos Basin for Western Mongolian birds).Based on this new knowledge of the biogeographical subpopulation structure of the Swan Goose,we need to combine data on subpopulation size,their distribution throughout the annual life cycle and conservation status,to develop more effective conservation strategies and measures to reverse population decline throughout the range.

Autumn migration of Ospreys from two distinct populations in Poland reveals partial migratory divide

Background:Long-term ringing and telemetry studies show that the Osprey(Pandion haliaetus)is a broad-front migrant following different migratory flyways,depending on the geographical location of their breeding populations.We have investigated two distinct and declining populations of Osprey in Poland,separated by only a few hundred kilometres,and hypothesised they may exhibit two different migration routes.We followed mortality causes,comparing them between migration and stationary phases of annual cycle,as well as between two distinct populations.Methods:Nineteen Ospreys,both juveniles and adults,were equipped with GPS loggers in 2017-2020 in two populations in western and eastern Poland and followed on their autumn migration.We calculated the distance they covered on the migration,number of stopover days,migration duration,daily distances covered and departure dates to compare them between age and sex classes and between the eastern and western populations.Results:Ospreys from the western and eastern populations showed a partial migratory divide.While the first migrated through a western flyway,the second followed a central flyway,resulting in crossing the Mediterranean Sea in distant passes that affected the distance covered.Annual mortality reached at least 67%in juveniles and at least 57%in adults.Conclusions:We showed that two distinct Osprey populations in Poland revealed a partial migratory divide,with one covering greater distances over sea and deserts over the central flyway.This might affect individual survival rates and contribute to a steeper decline in one of the populations.In order for this to be confirmed,more individuals still have to be followed.

Differing migration patterns and year-round habitat-use of allopatric nesting Eastern Tundra Bean Geese(Anser fabalis serrirostris)in East Asia

Sympatric Chinese-wintering Eastern Tundra Bean Geese(Anser fabalis serrirostris,ETBG)breed in two widely separated Arctic areas(Central Russian Arctic and Anadyr region);South Korean-wintering birds(Chaun-South Korea)breed in a third discrete area between these two.Such winter/summer segregation likely structures the population,potentially resulting in distinct migration patterns and habitat-use throughout the annual cycle.We tracked individuals using GPS-GSM transmitters from all three of these geographically discrete ETBG subpopulations to see whether this was the case,testing for differences in migration patterns,seasonal and diurnal habitat-use using remotely sensed land-cover mapping.Mean migration distance of Central Arctic-China and Chaun-South Korea individuals did not differ significantly,but Anadyr-China birds travelled 15–24%further(mean:1140 km,P<0.001).Despite this,mean spring migration durations were longest among Central ArcticChina ETBG,significantly longer than Anadyr-China geese,due to significantly longer stopovers,which were significantly longer than Chaun-South Korea birds.Autumn migration duration of Central Arctic-China and Chaun-South Korea individuals was significantly shorter than in spring,with fewer,shorter stopovers.Lack of significant differences in migration and stopover duration or numbers of stopovers between spring and autumn among Anadyr-China ETBG confirms this is a plastic trait,differing between subpopulations responding to prevailing conditions.Migration patterns and habitat-use differed significantly between all three ETBG subpopulations,although all tended to use wetlands more at night and croplands more in daytime in winter,suggesting specific adaptations and responses to differing conditions encountered along their different migration routes.Although untestable,we speculate that differences in habitat-use may affect fitness levels and genetic exchange between subpopulations,but based on our observations,conclude clear differences in migration and foraging ecology between these elements of the same subspecies,even in winter sympatry.

Migration routes and strategies of Grey Plovers (Pluvialis squatarola) on the East Atlantic Flyway as revealed by satellite tracking

Background:While the general migration routes of most waders are known,details concerning connectivity between breeding grounds, stopover sites and wintering grounds are often lacking.Such information is critical from the conservation perspective and necessary for understanding the annual cycle.Studies are especially needed to identify key stopover sites in remote regions. Using satellite transmitters, we traced spring and autumn migration routes and connectivity of Grey Plovers on the East Atlantic Flyway.Our findings also revealed the timing,flight speed, and duration of migrations. Methods:We used ARGOS satellite transmitters to track migration routes of 11 Grey Plovers that were captured at the German Wadden Sea where they had stopped during migration.Birds were monitored for up to 3 years,2011-2014.Results:Monitoring signals indicated breeding grounds in the Taimyr and Yamal regions;important staging sites on the coasts of the southern Pechora Sea and the Kara Sea;and wintering areas that ranged from NW-Ireland to Guinea Bissau.The average distance traveled from wintering grounds to breeding grounds was 5534 km. Migration duration varied between 42 and 152 days;during this period birds spent about 95% of the time at staging sites.In spring most plovers crossed inland Eastern Europe, whereas in autumn most followed the coastline.Almost all of the birds departed during favorable wind conditions within just 4 days (27-30 May) on northward migration from the Wadden Sea.In spring birds migrated significantly faster between the Wadden Sea and the Arctic than on return migration in autumn (12 vs.37 days),with shorter stopovers during the northward passage.Conclusions:Our study shows that satellite tags can shed considerable light on migration strategies by revealing the use of different regions during the annual cycle and by providing detailed quantitative data on population connectivity and migration timing.