Cygnus Cygnus Research Articles

Using satellite tracking to assess the use of protected areas and alternative roosts by Whooper and Bewick's Swans

Protected areas are one of the major tools used in the conservation of biodiversity, but animals are unlikely always to remain within these human‐made boundaries. Understanding when and why species choose to leave protected areas can help us to improve the effectiveness of these management tools. Here, we investigate the use of protected and non‐protected areas by two migratory species undergoing rapid wintering population changes in northwest Europe: Whooper Swans Cygnus cygnus and Bewick's Swans Cygnus columbianus bewickii. Global positioning system tags were fitted to 15 Whooper Swans in winter 2008/09 and to 18 Bewick's Swans from winter 2013/14 to 2014/15 at the Ouse Washes Special Protection Area (an internationally important roost for wintering waterbirds) and on adjacent fields in southeast England. Here, swans feed on farmland during the day but return to designated reserves to roost at night, where they receive protection from predators and disturbance within managed roost habitats. When swans roost elsewhere at alternative sites, they may face more adverse conditions, and so understanding the extent and causes of the use of alternative roosts is important for swan conservation efforts. The alternative roosting proportion, defined as the proportion of nights spent outside protected reserves, was 0.237 for Bewick's Swans and challenging to quantify accurately for Whooper Swans. A generalized additive mixed model to model repeated measurements on individuals showed that the proportion of time that Bewick's Swans spent at alternative roosts correlated positively with river level and negatively with temperature. Competition and foraging flight distances are thought to drive these relationships, as swans seek access both to roost space and to nearby feeding habitats. Our findings improve our understanding of the environmental conditions under which migratory waterbirds may choose to roost outside protected areas.

Life in the fast and slow lanes: contrasting timing of annual cycle events in high‐ and mid‐latitude breeding Whooper Swans (Cygnus cygnus)

Life in the fast and slow lanes: contrasting timing of annual cycle events in high‐ and mid‐latitude breeding Whooper Swans (<i>Cygnus cygnus</i>)

Фауна и население птиц гористых районов южного берега Варангер-фьорда

The article presents data from field studies of the fauna and bird population of mountainous areas of the Varangerfjord southern coast. This area has erspectives to be included in the boundaries of the projected “Voryema” Federal Reserve. We carried field studies during the 2019–2021 breeding period in the northwestern part of the Pechengsky district of the Murmansk region. In the course of the work, we surveyed mountainous areas from areas adjacent to the Voryema River valley to areas near the iinahamari settlement. The total length of survey routes was 81.8 km. Analysis of the received field materials shows that at least 53 bird species occur in the breeding season. Tundra and rocky areas are breeding sites for skuas, gulls, loons, and a number of sandpipers’ and ducks’ species. The combination of different habitats creates the possibility of the presence of four species of pipits on this territory at once. Therefore, this territory can be a good model for studying the effects of climate change on a number of closely related species living together. In general, the results of the study show that the surveyed territories of the mountainous areas of the Varangerfjord southern coast are promising for inclusion in the boundaries of the projected Voryema Federal Reserve. They have a characteristic bird population structure and serve as breeding grounds for a number of rare species (whooper swan, whooper, golden eagle, white-tailed eagle, kestrel, white-throated thrush).

Novel Avian Influenza A(H5N6) Virus in Wild Birds, South Korea, 2023.

We isolated novel reassortant avian influenza A(H5N6) viruses containing genes from clade 2.3.4.4b H5N1 virus and low pathogenicity avian influenza viruses in carcasses of whooper swans and bean geese in South Korea during December 2023. Neuraminidase gene was from a clade 2.3.4.4b H5N6 virus infecting poultry and humans in China.

Multi-Scale Habitat Selection by the Wintering Whooper Swan (Cygnus cygnus) in Manas National Wetland Park, Northwestern China

Habitat selection has been a central focus of animal ecology, with research primarily concentrating on habitat choice, utilization, and evaluation. However, studies confined to a single scale often fail to reveal the habitat selection needs of animals fully and accurately. This paper investigates the wintering whooper swan (Cygnus cygnus) in Manas National Wetland Park, Xinjiang, using satellite tracking to determine their locations. The Maximum Entropy model (MaxEnt) was applied to explore the multi-scales habitat selection needs of Manas National Wetland Park’s wintering whooper swans across nighttime, daytime, and landscape scales. This study showed that the habitat selection of the wintering whooper swans varied in different scales. At the landscape scale, wintering whooper swans prefer habitats with average winter precipitations of 6.9 mm and average temperatures of −6 °C, including water bodies and wetlands, indicating that climate (precipitation and temperature) and land type (wetlands and water bodies) influence their winter habitat selection. During daytime, whooper swans prefer areas close to wetlands, water bodies, and bare land, with a more dispersed distribution of water bodies. For nighttime, they tend to choose areas within the wetland park where human disturbance is minimal and safety is higher. This study can provide scientific basis and data support for habitat conservation and management of wintering waterbirds like whooper swans, recommending targeted conservation measures to effectively manage and protect the wintering grounds of whooper swans.

Diagnosis of Coxofemoral Joint Luxation in a Whooper Swan (Cygnus Cygnus) Using Computed Tomography and Radiography

Diagnosis of Coxofemoral Joint Luxation in a Whooper Swan (<i>Cygnus Cygnus</i>) Using Computed Tomography and Radiography

Optimised PCR assays for detecting elusive waterfowl from environmental DNA.

For many aquatic and semiaquatic mammal, amphibian and fish species, environmental DNA (eDNA) methods are employed to detect species distribution and to monitor their presence, but eDNA is much less employed for avian species. Here, we developed primers for the detection of true geese and swan species using eDNA and optimised a PCR protocol for eDNA. We selected taiga bean goose (Anser fabalis fabalis) as our focal (sub)species and sampled water from lakes, from which the presence of taiga bean goose was visually confirmed. To test, if taiga bean goose DNA could be detected among DNA of other goose species, we similarly sampled eDNA from a zoo pond housing several Anatidae species. We were able to detect taiga bean goose DNA in all but one of the tested lakes, including the zoo pond. The primers developed are not species-specific, but rather specific to the genus Anser, due to the close relatedness of Anser species, which prevented the development of species-specific primers and the use of, for example, quantitative PCR. We also developed eDNA primers for Branta species and Cygnus species and tested these primers using the same samples. Canada goose (B. canadensis) and barnacle goose (B. leucopsis) DNA were only detected in the zoo pond (in which they were present), as the sampled natural lakes fall outside the range of these species. We detected whooper swan (C. cygnus) DNA in three lakes and the zoo pond (in which the species was present). The eDNA method presented here provides a potential means to monitor elusive goose species and to study the co-occurrence of large waterfowl.

Coeffects of temperature and photoperiod on the age-related timing of spring migration of Whooper swans via satellite tracking

Extrinsic and endocrine factors are important mechanisms influencing the timing of spring bird migration. Whooper swans (Cygnus cygnus), including 122 adults and subadults over one year old and 98 juveniles under one year old, were satellite tracked to obtain detailed locational data at a wintering ground from 2015 to 2020. We assessed the effects of temperature, wind, photoperiod, available food resources, and sex hormones on age-related timing of spring migration. Our results suggested that both photoperiod and temperature had the greatest impacts on the timing of spring migration of adults, subadults and juveniles when food resources and wind conditions were favourable. With increasing photoperiod and temperature, the peak sex hormone concentrations of adults and subadults occurred one month earlier than that of juveniles, which corresponded to the peak of their departure time. Our study showed the synergistic impact of photoperiod and temperature and their variation among adults, subadults and juveniles on the initiation of spring migration. Compared with juveniles, adults and subadults with spring migration experience and reproductive needs could adjust their behaviours more quickly before departure based on changes in environmental conditions.

Ecological and phylogenetic aspects of the spring diet of three palaearctic species of swans

The quality of swans' nutrition at spring migration stopovers is important for their successful breeding. It is of great interest to study the differences in nutrition of different swan species when sharing the same habitat. Microscopic analysis of Cygnus olor, C. cygnus, and C. columbianus bewickii feces collected in the eastern part of the Gulf of Finland in February-April 2014–2019 was performed. We measured food preferences of the three swan species using non-metric multidimensional scaling (NMDS). The width and overlap of dietary niches were also calculated. The diet of C. olor consists almost entirely of soft submerged aquatic vegetation, mainly macroalgae. Samples of the other two species except macroalgae contained large amounts of young shoots and roots of rigid semi-submerged and coastal vegetation. The dietary niche of C. cygnus is the most isolated because it is dominated by thick rhizomes of Phragmites australis, which are hardly used by other swan species. The diet of Bewick’s swans was similar in many respects to that of the Mute swan, but Bewick’s swans much more often preferred vegetative parts of submerged and semi-submerged plants, such as Stuckenia pectinata, Potamogeton perfoliatus, Sparganium sp., Nuphar lutea, and others. Notably, the dietary niches of Mute swan and Whooper swan overlapped as much as possible in February March during a period of severe food shortage, in contrast to later periods in spring when food was more abundant and varied. In general, differences in diets are well explained by differences in the morphology of birds. Comparison of tarsometatarsus indices shows that C. olor is the most water-related species. C. olor has the longest neck and its beak has the strongest filter features, whereas beaks of the other two species shows noticeable “goose-like grazing” features. Moreover, C. Cygnus has the most powerful beak. These features are due to the history of species. The formation of C. olor occurred during the Miocene-Pliocene of the Palaearctic in the warm eutrophic marine lagoons of the Paratethys with abundant soft submerged vegetation. The evolution of C. cygnus and C. c. bewickii took place in Pleistocene. At that time, periglacial and thermokarst water bodies on permafrost became widespread in the Palearctic, as well as dystrophic peat lakes with much poorer submerged aquatic vegetation, but well-developed coastal and semi-submerged vegetation.

Evolution and Spread of Highly Pathogenic Avian Influenza A(H5N1) Clade 2.3.4.4b Virus in Wild Birds, South Korea, 2022-2023.

During October 2022-March 2023, highly pathogenic avian influenza (HPAI) A(H5N1) clade 2.3.4.4b virus caused outbreaks in South Korea, including 174 cases in wild birds. To understand the origin and role of wild birds in the evolution and spread of HPAI viruses, we sequenced 113 HPAI isolates from wild birds and performed phylogenetic analysis. We identified 16 different genotypes, indicating extensive genetic reassortment with viruses in wild birds. Phylodynamic analysis showed that the viruses were most likely introduced to the southern Gyeonggi-do/northern Chungcheongnam-do area through whooper swans (Cygnus cygnus) and spread southward. Cross-species transmission occurred between various wild bird species, including waterfowl and raptors, resulting in the persistence of HPAI in wild bird populations and further geographic spread as these birds migrated throughout South Korea. Enhanced genomic surveillance was an integral part of the HPAI outbreak response, aiding in timely understanding of the origin, evolution, and spread of the virus.

Comparison of nest site selection in Mute Swan Cygnus olor and the expanding Whooper Swan Cygnus cygnus

The warming climate is giving migratory birds new opportunities to extend their breeding ranges. These expansions may have a significant impact on other local bird communities. Here, we investigate the nest site selection of Mute Swan Cygnus olor, and the expanding Whooper Swan Cygnus cygnus. The study aims to assess the differences in habitat use by these two swan species in a lowland anthropogenic landscape. It examines the number of breeding pairs and the surface areas of nesting zones in different habitat types. The field procedures involved the use of unmanned aerial vehicles (UAVs) to survey and locate nests, with geotagged photographs taken to map nest locations. Our results show that Mute Swans primarily occupy oxbows, while Whooper Swans predominantly nest in pond complexes. Moreover, GLM models indicate that Mute Swans tend to choose open areas within a radius of 200 m around the nests, whereas Whooper Swans avoid built-up areas, often choosing forested sites within a radius of 500 m of their nests. These findings suggest that the expansion of the Whooper Swan population has led to changes in the breeding behaviour and habitat use of sympatric Mute Swan populations. The territorial behaviour and aggression of Whooper Swan may be driving Mute Swan away from fishpond habitats. We conclude that interactions between the two swan species are dynamic and have not yet stabilized, so this is an issue that needs to be closely monitored. Understanding these dynamics is essential for the effective conservation and management of wetland habitats in the face of ongoing climate change and shifting breeding ranges of birds.

Metagenomic analysis of gut microbiome and resistome of Whooper and Black Swans: a one health perspective

BackgroundWith the promotion of “One Health,” the health of animals and their impact on the environment have become major concerns recently. Widely distributed in China, the whooper swans (Cygnus cygnus) and black swans (Cygnus atratus) are not only important to the ecological environment, but they may also potentially influence public health security. The metagenomic approach was adopted to uncover the impacts of the gut microbiota of swans on host and public health.ResultsIn this study, the intestinal microbiome and resistome of migratory whooper swans and captive-bred black swans were identified. The results revealed similar gut microbes and functional compositions in whooper and black swans. Interestingly, different bacteria and probiotics were enriched by overwintering whooper swans. We also found that Acinetobacter and Escherichia were significantly enriched in early wintering period swans and that clinically important pathogens were more abundant in black swans. Whooper swans and black swans are potential reservoirs of antibiotic resistance genes (ARGs) and novel ARGs, and the abundance of novel ARGs in whooper swans was significantly higher than that in black swans. Metagenomic assembly–based host tracking revealed that most ARG-carrying contigs originated from Proteobacteria (mainly Gammaproteobacteria).ConclusionsThe results revealed spatiotemporal changes in microbiome and resistome in swans, providing a reference for safeguarding public health security and preventing animal epidemics.

Stimulating effects of whooper swans’ behaviors on nutrient releasing from the sediments caused by different human feeding intensities in the swan Lake, China

In many shallow water lakes of China, as the numbers of tourists observing waterflow increases, the amount of supplemental food provided to waterflow also increases. However, little attention has been paid to the role of waterfowl’s behavior perturbation in N and P nutrients releasing from the sediment. In this study, five feeding experiments were undertaken in the Swan Lake (Shandong Province, northern China) during the wintering season and a noticeable release of nutrients in all experiments was found by the disturbance of the swan behaviors. The release of TN and TP was through three stages including the non-release stage, the rapid release stage, and the stable release stage. Moreover, supplemental food also influenced the swan behavior changes and triggered the frequency of the swans’ grazing and aggression. The aggressive behaviors among the swans stirred nutrient (N & P) releasing from sediments and altered TN and TP concentrations in the water columns, indicating that the aggressive behaviors may be a significant factor in affecting the TN and TP releasing from the sediment. Human feeding intensity (HFI) suggested > 850 g of supplemental corn can be an optimal way to aid in avoiding foraging competition among the swans to control nutrient release by three levels of human feeding intensity assessment. Our findings demonstrate that under the swans’ optimal foraging need in natural versus artificial feeding scenarios, the swans acted as biological pumps to increase nutrient release. There is a need for a systematic and evidence-based feeding strategy for swans, with greater restrictions on the provision of small food items scattered by visitors. Our study provided novel insights into the release mechanism of N and P from bioturbation and could help to inform a whooper swan conservation strategy in coastal wetlands and nature reserves.

Comparative analysis of the gut microbiota of wild wintering whooper swans (Cygnus Cygnus), captive black swans (Cygnus Atratus), and mute swans (Cygnus Olor) in Sanmenxia Swan National Wetland Park of China.

The gastrointestinal microbiota, a complex ecosystem, is involved in the physiological activities of hosts and the development of diseases. Birds occupy a critical ecological niche in the ecosystem, performing a variety of ecological functions and possessing a complex gut microbiota composition. However, the gut microbiota of wild and captive birds has received less attention in the same region. We profiled the fecal gut microbiome of wild wintering whooper swans (Cygnus Cygnus; Cyg group, n = 25), captive black swans (Cygnus Atratus; Atr group, n = 20), and mute swans (Cygnus Olor;Olor group, n = 30) using 16S rRNA gene sequencing to reveal differences in the gut microbial ecology. The results revealed that the three species of swans differed significantly in terms of the alpha and beta diversity of their gut microbiota, as measured by ACE, Chao1, Simpson and Shannon indices, principal coordinates analysis (PCoA) and non-metricmulti-dimensional scaling (NMDS) respectively. Based on the results of the linear discriminant analysis effect size (LEfSe) and random forest analysis, we found that there were substantial differences in the relative abundance of Gottschalkia, Trichococcus, Enterococcus, and Kurthia among the three groups. Furthermore, an advantageous pattern of interactions between microorganisms was shown by the association network analysis. Among these, Gottschalkia had the higher area under curve (AUC), which was 0.939 (CI = 0.879-0.999), indicating that it might be used as a biomarker to distinguish between wild and captive black swans. Additionally, PICRUSt2 predictions indicated significant differences in gut microbiota functions between wild and captive trumpeter swans, with the gut microbiota functions of Cyg group focusing on carbohydrate metabolism, membrane transport, cofactor, and vitamin metabolism pathways, the Atr group on lipid metabolism, and the Olor group on cell motility, amino acid metabolism, and replication and repair pathways. These findings showed that the gut microbiota of wild and captive swans differed, which is beneficial to understand the gut microecology of swans and to improve regional wildlife conservation strategies.

Restoration of wetlands in Eulsukdo at the Nakdong River Estuary, feeding effects, and ascending flight patterns of Whooper swan - With a focus on winter migratory birds -

Restoration of wetlands in Eulsukdo at the Nakdong River Estuary, feeding effects, and ascending flight patterns of Whooper swan - With a focus on winter migratory birds -

Avian species survey with citizen-science data in Janghang Wetland, Goyang, Republic of Korea.

Monitoring of avian populations in Janghang Wetland, Goyang, Republic of Korea (ROK) is based on citizen science (also called community-based monitoring). This monitoring data can be used to track avian density, population status and waterbird census at local, national and regional levels. The Ministry of Environment (MoE) ROK has surveyed since 1999, including Odusan Unification Tower to Ilsan Bride, which connects the cities of Gimpo and Goyang along the Han River estuary. However, it has not covered Janghang Wetland, which is located in the Han River estuary at the transboundary between the two Koreas. The Janghang Wetland is a protected wetland in the Demilitarized Zone (DMZ) between the two Koreas. In 2019, Janghang Wetland was designated as a Flyway Network Site by Goyang City and the East Asian-Australasian Flyway Partnership. This Network site is a voluntary collaboration and includes many internationally significant wetlands for waterbirds that still lack formal national protection. In addition, it was designated as a Ramsar site in 2021. The wetland currently supports wintering population of White-naped Crane (Grusvipio), species listed as vulnerable and Tundra Bean Goose (Ansercygnoides), spring-autumn migration population of Swan Goose (Ansercygnoid), species listed as vulnerable and a breeding population of Black-faced Spoonbill (Plataleaminor), species listed as endangered in summer. We provide data that the Janghang Wetland is a significant area for migration and breeding for waterbirds; and that Han River estuary is also internationally important for waterbirds during the migratory bird season. We observed 14 orders, 42 families and 132 species. The surveys also observed the critically-endangered Black-faced Spoonbill (Plataleaminor), Swan Goose (Ansercygnoides), White-naped Crane (Grusvipio), Whooper Swan (Cygnuscygnus) and Peregrine Falcon (Falcoperegrinus). We also observed the Black-faced Spoonbill, Great Egret, Little Egret, Great Cormorant, Eastern Spot-billed Duck, Pheasant and Brown-eared Bulbul at the sensor camera point and White-naped Crane, Hooded Crane, Bean Goose, White-fronted Goose, Snow Goose, Swan Goose, Great Cormorant and Eastern Spot-billed Duck at the closed-circuit television camera point from the camera-trap surveys. Based on the species recorded, the survey area is of clear importance for biodiversity conservation.

Sensitivity analysis of collision risk at wind turbines based on flight altitude of migratory waterbirds

Abstract A rapid increase in wind power generation has led to bird collisions becoming a serious problem worldwide. Developing useful sensitivity maps to select low‐risk sites for birds is an urgent issue. For migratory birds, such as geese and swans, that visit different habitats throughout their life cycle, it is important to conduct risk assessments that take into account their behavioural characteristics in each habitat. Geese and swans fly and migrate at varying altitudes (above the ground) ranging from 10 to hundreds of metres. Accurate predictions of avian flight altitudes are essential in assessing the risks of collisions with human‐made structures. We first obtained location data for four species of geese and swans to identify their spring migratory routes within Japan (Bean Goose Anser fabalis and Anser serrirostris, Greater White‐fronted Goose Anser albifrons, Tundra Swan Cygnus columbianus bewickii and Whooper Swan Cygnus cygnus). As all four species used the same roosts and overlapping foraging areas from winter to spring, a single migratory route was defined by integrating the location data of the four species. Flight trajectories were tracked using an ornithodolite. The median flight height for these four species in all landscape types was 150 m or less. Then a LASSO regression model was created with flight altitude obtained as the response variable and topographic and landscape factors as explanatory variables. Trends in flight altitude with environmental differences were similar for the four species, indicating that topographical factors strongly influence flight altitude. Finally, a statistical model was used to predict flight altitudes along migration routes. The sensitivity maps we generated showed that for all four species, most flight heights during spring were within the wind turbine range, suggesting that their risk of collision with wind turbines was greater along their migratory route. Sensitivity maps that accurately reflect avian flight characteristics help provide useful information when considering the location of further wind turbine construction.

Demographic rates reveal the benefits of protected areas in a long-lived migratory bird

Recent studies have suggested that protected areas often fail to conserve target species. However, the efficacy of terrestrial protected areas is difficult to measure, especially for highly vagile species like migratory birds that may move between protected and unprotected areas throughout their lives. Here, we use a 30-y dataset of detailed demographic data from a migratory waterbird, the Whooper swan (Cygnus cygnus), to assess the value of nature reserves (NRs). We assess how demographic rates vary at sites with varying levels of protection and how they are influenced by movements between sites. Swans had a lower breeding probability when wintering inside NRs than outside but better survival for all age classes, generating a 30-fold higher annual growth rate within NRs. There was also a net movement of individuals from NRs to non-NRs. By combining these demographic rates and estimates of movement (into and out of NRs) into population projection models, we show that the NRs should help to double the population of swans wintering in the United Kingdom by 2030. These results highlight the major effect that spatial management can have on species conservation, even when the areas protected are relatively small and only used during short periods of the life cycle.

The use of drones to study the breeding productivity of Whooper Swan Cygnus cygnus

This research was carried out in north-eastern Poland, where Whooper Swan Cygnus cygnus is a sparse breeder. Whooper Swan is timid and exhibits a tendency to hide in emergent vegetation. A drone was used to improve the effectiveness of research into its breeding success and offspring productivity. The breeding density of Whooper Swan in the study area in 2022 was 10 pairs/100 km2. The number of breeding birds detected at the beginning of the breeding season did not differ according to the method used (drone vs ground). The breeding productivity of the sample of swans studied (N = 36) was 2.19 cygnets per breeding pair using the ground method, but 3.71 per pair with the drone, a significant difference (p-value of the Wilcoxon test = 0.0148). The traditional method showed that 50% of the pairs had bred successfully, whereas with the drone this figure was 79%. The birds either did not react to the drone’s presence or else moved slowly away. The drone study of Whooper Swan breeding productivity was considerably faster (9 min per site vs 1–2 h ground survey), more precise, and less invasive for the birds than a traditional ground survey.

Counting young birds: A simple tool for the determination of avian population parameters.

Population parameters are usually determined from mark-recapture experiments requiring laborious field work. Here, we present a model-based approach that can be applied for the determination of avian population parameters such as average individual life expectancy, average age in the population, and generation length from age-differentiated bird counts. Moreover, the method presented can also create age-specific results from lifetime averages using a deterministic exponential function for the calculation of parameters of interest such as age-dependent mortality and age distribution in the population. The major prerequisites for application of this method are that young and adult birds are easily distinguishable in the field as well as the existence of sufficiently large data sets for error minimization. Large data sets are nowadays often available through the existence of so-called "citizen science" databases. Examples for the determination of population parameters are given for long-living migratory birds which travel as families in large groups such as the Common Crane and the Whooper Swan. Other examples include long-living partially migratory birds staying together in large flocks which do not travel as families such as the Black-headed Gull, and also short-living songbirds where at least from one sex young and adult birds are easily differentiable such as the male Black Redstart.