International census and population trends for Bewick’s Swans Cygnus columbianus bewickii wintering from the East Mediterranean to Central Asia

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Published: Nov 14, 2024
Keywords:
central Asia, distribution, population trends, southeast Europe

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Eileen C. Rees
Sonia Rozenfeld
Didier Vangeluwe
Panagiotis Ioannidis
Kiraz Erciyas-Yavuz
Anna Belousova
Eldar Rustamov
Alexander Solokha
Elchin Sultanov
Christine Kowallik
Danae Portolou
Artyom Khrokov
Marki Šćiban
Vitalie Ajder
Marco Zenatello
Kees Koffijberg
George Kirtaev
Natalia Rogova
Mamikon Ghasabyan
Kevin A. Wood
Tom Langendoen
Szabolcs Nagy
Preben Clausen
Anthony D. Fox

Abstract

Trends in abundance and changes in the distribution of the Northeast Europe/ Northwest Europe Bewick’s Swan Cygnus columbianus bewickii population have been studied in detail since the second half of the 20th century, but much less is known about the Northwestern Siberia/Caspian population which was estimated at 1,000–1,500 individuals at the turn of the century. Here, we describe the results of the first species-specific mid-winter International Bewick’s Swan Census (IBSC) covering the East Mediterranean to Central Asia, made in January 2020. We also use longer-term data collated by Wetlands International through the annual International Waterbird Census (IWC) programme to construct trends in wintering numbers in the region. Results from the IBSC and IWC both showed a marked increase in population size for the Northwestern Siberia/Caspian Bewick’s Swans over the past two decades. A total of 6,819 was recorded during the IBSC and there was a five-year mean of 9,111 ± 4,300 swans reported to the IWC (for the years 2018–2022) with a peak count of 13,775 in 2019. An aerial survey of the Volga Delta in the northern Caspian Sea in 2020, rarely covered because of the logistical difficulties of carrying out mid-winter counts in the region, found an estimated 551 Bewick’s Swans wintering at the site. There was marked annual variation in the IWC counts recorded from 2017 onwards, although the reasons for these fluctuations remain unknown. Trends analysis suggested a slow increase over time from 2000–2015, followed by a period of rapid increase during 2015–2017, then a weak decline in 2017–2022. Given that the IBSC and the IWC have provided totals of > 6,000 Bewick’s Swans in five of the last six years, however, we propose that the new population estimate should be increased to 6,000–13,000 birds, pending further comprehensive surveys of the whole region.

Article Details

How to Cite
Rees, E. C., Rozenfeld, S., Vangeluwe, D., Ioannidis, P., Erciyas-Yavuz, K., Belousova, A., … Fox, A. D. (2024). International census and population trends for Bewick’s Swans Cygnus columbianus bewickii wintering from the East Mediterranean to Central Asia. Wildfowl, 179–201. Retrieved from https://tidsskrift.dk/Wildfowl/article/view/156361
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Wildfowl Special Issue No. 7
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Standard Papers

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References

Atkinson-Willes, G.L., Scott, D.A. & Prater, A.J. 1982. Criteria for selecting wetlands of international importance. In M. Spagnesi (ed.), Proceedings of the Conference on the Conservation of Wetlands of International Importance Especially as Waterfowl Habitat. Cagliari, Italy, 24–29 November 1980, pp. 1017–1042. Supplemento alle Ricerche di Biologia della Selvaggina 8 (1).

Beekman, J., Koffijberg, K., Hornman, M., Wahl, J., Kowallik, C., Hall, C., Devos, K., Clausen, P., Laubek, B., Luigujõe, L., Wieloch, M., Boland, H., Švažas, S., Nilsson, L., Stı¯pniece, A., Keller, V., Degen, A., Shimmings, P., Larsen, B.-H., Portolou, D., Langendoen, T., Wood, K. & Rees, E.C. 2019. Long-term population trends and shifts in distribution of Bewick’s Swans wintering in northwest Europe. Wildfowl (Special Issue No. 5): 73–102.

Brides, K., Wood, K.A., Hall, C., Burke, B., McElwaine, G., Einarsson, Ó., Calbrade, N., Hill, O. & Rees, E.C. 2021. The Icelandic Whooper Swan Cygnus cygnus population: current status and long-term (1986–2020) trends in its numbers and distribution. Wildfowl 71: 29–57.

Carboneras, C., Kirwan, G.M. & Sharpe, C.J. 2020. Red-breasted Goose (Branta ruficollis), version 1.0. In J. del Hoyo, A. Elliott, J. Sargatal, D.A. Christie & E. de Juana (eds.), Birds of the World. Cornell Lab of Ornithology, Ithaca, New York, USA. Available online at https://doi.org/10.2173/ bow.rebgoo1.01 (last accessed 6 May 2024).

Clausen, K.K., Madsen, J., Cottaar, F., Kuijken, E. & Verscheure, C. 2018. Highly dynamic wintering strategies in migratory geese: Coping with environmental change. Global Change Biology 24: 3214–3225.

Cong, P.H., Cao, L., Fox, A.D., Barter, M., Rees, E.C., Jiang, Y., Ji, W., Zhu, W. & Song, G. 2011. Changes in Tundra Swan Cygnus columbianus bewickii distribution and abundance in the Yangtze River floodplain. Bird Conservation International 21: 260–265.

Delany, S. & Scott, D. 2002. Waterbird Population Estimates – Third Edition. Wetlands International Global Series No. 12. Wetlands International, Wageningen, The Netherlands.

Delany, S., Reyes, C., Hubert, E., Pihl, S., Rees, E., Haanstra, L. & van Strien, A. 1999. Results from the International Waterbird Census in the Western Palearctic and Southwest Asia 1995 and 1996. Wetlands International Publication No. 54, Wetlands International, Wageningen, the Netherlands.

Eggers, H. 2018. Observations of Bewick’s Swans at the Evros Delta, in Greece and Turkey, in February 2017. Swan News 14: 18–21.

Fang, L., Zhang, J., Zhao, Q., Solovyeva, D., Vangeluwe, D., Rozenfeld, S.B., Lameris, T., Xu, Z., Bysykatova, I., Batbayar, N., Konishi, K., Moon, O.-K., He, B., Koyama, K., Moriguchi, S., Shimada, T., Park, J.-Y., Kim, H., Liu, G., Hu, B., Gao, D., Ruan, L., Natsagdorj, T., Davaasuren, B., Antonov, A., Mylnikova, A., Stepanov, A., Kirtaev, G., Zamyatin, D., Kazantzidis, S., Sekijima, T., Damba, I., Lee, H., Zhang, B., Xie, Y., Rees, E.C., Cao, L. & Fox, A.D. 2020. Two distinctive flyways with different population trends of Bewick’s Swan Cygnus columbianus bewickii in East Asia. Wildfowl (Special Issue No. 6): 13–42.

GSDSG 2023. Goose, Swan, and Duck Study Group of Northern Eurasia’s Database of the Results of Aerial Surveys and Remote Tracking of Anseriformes in Russia. Goose, Swan, and Duck Study Group of Northern Eurasia, Moscow Russia. Accessible at http://rggsurveys.ru/ (last accessed 20 August 2024).

Handrinos, G.I. The numbers and distribution of swans (Cygnus sp.) wintering in Greece. In M. Birkan, J. van Vessem, P. Havet, J. Madsen, B. Trolliet & M. Moser (eds.), Proceedings Anatidae 2000 Conference, Strasbourg, France, 5–9 December 1994. Gibier Faune Sauvage, Game Wildlife 13: 463–476.

Handrinos, G., Kazantzidis, S., Alivizatos, Ch., Akriotis, T. & Portolou, D. 2015. International Waterbird Census in Greece (1968–2006). Analysis of the Populations of Wildfowl (Anseri formes) and the Coot (Fulica atra). Hellenic Ornithological Society – Hellenic Bird Ringing Centre, Athens, Greece.

Hellenic Rarities Committee. 2007. Annual Report – 2006. Hellenic Ornithological Society, Athens, Greece. Available at https://files. ornithologiki.gr/docs/rarities/annual_report_ 2006_en.pdf (last accessed 24 April 2023).

Linssen, H., van Loon, E.E., Shamoun-Baranes, J.Z., Nuijten, R.J.M. & Nolet, B.A. 2023. Migratory swans individually adjust their autumn migration and winter range to a warming climate. Global Change Biology 29: 6888–6899.

Litvin, K. & Vangeluwe, D. 2016. The Bewick’s Swan is a paradox. Swan News 12: 12.

Lüdecke, D., Ben-Shachar, M.S., Patil, I., Waggoner, P. & Makowski, D. 2021. performance: An R package for assessment, comparison and testing of statistical models. Journal of Open Source Software 6: 3139.

Madsen, J., Schreven, K.H.T., Jensen, G.H., Johnson, F.A., Nilsson, L., Nolet, B.A. & Pessa, J. 2023. Rapid formation of new migration route and breeding area by Arctic geese. Current Biology 33: 1162–1170.

Muggeo, V.M. 2008. segmented: an R Package to Fit Regression Models with Broken-Line Relationships. R News 8: 20–25.

Nagy, S. 2023. Delineation of biogeographic populations of the Bewick’s Swan (Cygnus columbianus bewickii): proposal to change population delineations. Document AEWA/ TC No. 18.9, prepared by Wetlands International for Agenda Item 9.1 of the 18th Meeting of the AEWA Technical Committee, 14–16 March 2023. Agreement on the Conservation of African-Eurasian Migratory Waterbirds, Bonn, Germany. Available online at https://www.unep-aewa. org/sites/default/files/document/aewa_tc18 _9_change_delineation_populations_bewicks _swan.pdf (last accessed 4 April 2024).

Nagy, S., Petkov, N., Rees, E.C., Solokha, A., Hilton, G., Beekman, J. & Nolet, B. 2012. International Single Species Action Plan for the Northwest European Population of Bewick’s Swan (Cygnus columbianus bewickii). AEWA Technical Series No. 44. African-Eurasian Migratory Waterbirds Agreement, Bonn, Germany.

Nuijten, R.J.M., Wood, K.A., Haitjema, T., Rees, E.C. & Nolet, B.A. 2020. Concurrent shifts in wintering distribution and phenology in migratory swans: individual and generational effects. Global Climate Change 26: 4263–4275.

Pinheiro, J., Bates, D., DebRoy, S., Sarkar, D. & R Core Team. 2023. nlme: Linear and Nonlinear Mixed Effects Models. R package version 3.1–164. Available at https://CRAN.R-project.org/ package=nlme (last accessed 13 February 2024).

R Core Team 2022. R: A Language and Environment for Statistical Computing. Version 4.2.2. R Foundation for Statistical Computing, Vienna, Austria. https://www.r-project.org/

Rees, E.C. 1991. Distribution within the USSR of Bewick’s Swans Cygnus columbianus bewickii marked in Britain. Wildfowl (Special Supplement No. 1): 209–213.

Rees, E. 2006. Bewick’s Swan. T & A.D. Poyser, London, UK.

Rees, E.C. & Clausen, P. 2024. Swan research and conservation: a synthesis of information presented at the 7th International Swan Symposium. Wildfowl (Special Issue No. 7): 1–26.

Rees, E.C., Cao, L., Clausen, P., Coleman, J., Cornely, J., Einarsson, O., Ely, C., Kingsford, R., Ma, M., Mitchell, C.D., Nagy, S., Shimada, T., Snyder, J., Solovyeva, D., Tijsen, W., Vilina, Y., Włodarczyk, R. & Brides, K. 2019. Conservation status of the world’s swan populations, Cygnus sp. and Coscoroba sp.: a review of current trends and gaps in knowledge. Wildfowl (Special Issue No. 5): 35–72.

Rozenfeld, S.B., Volkov, S.V., Rogova, N.V., Soloviev, M.Yu., Kirtaev, G.V., Zamyatin, D.O. & Vangeluwe, D. 2019. Bewick’s swan (Cygnus bewickii): the expansion of Asian populations to the west, does it exist? Zoologicheskii Zhurnal 98(3): 302–313. [In Russian with English summary.]

Rozenfeld, S., Dmitriev, A., Ivanov, M. & Perkovsky, M. 2020a. Caspian Swan Survey: 8–11 February 2020. Goose, Swan and Duck Study Group of Northern Eurasia (RGG) Report to Wetlands International – European Association, Wageningen, the Netherlands.

Rozenfeld, S.B., Perkovskiy, M.N. Rogova N.V., Dmitriev, A.E. & Ivanov, M.N. 2020b. Results of the swan census in the Volga Delta in February 2020. Casarca 22: 38–43.

Scott, D.A. & Rose, P.M. 1996. Atlas of Anatidae Populations in Africa and Western Eurasia. Wetlands International, Wageningen, the Netherlands.

Syroechkovski, E.E. 2002. Distribution and population estimates for swans in the Siberian arctic in the 1990s. In E.C. Rees, S.L. Earnst & J. Coulson (eds.), Proceedings of the Fourth International Swan Symposium, 2001. Waterbirds 25 (Special Publication No. 1): 100–113.

Tijsen, W. & Koffijberg, K. 2021. The big brood count 2020! Swan News 16: 17.

Vangeluwe, D., Rozenfeld, S. & Kazantzidis, S. 2016. The odyssey of the Bewick’s Swan – another route to Greece. Swan News 12: 10–12.

Vangeluwe, D., Rozenfeld, S.B., Volkov, S.V., Kazantzidis, S., Morosov, V.V., Zamyatin, D.O. & Kirtaev, G.V. 2018. Migrations of Bewick’s Swan (Cygnus bewickii): new data on tagging the migration routes, stopovers, and wintering sites. Biology Bulletin 45: 90–101.

Wood, K.A., Nuijten, R.J.M., Newth, J.L., Haitjema, T., Vangeluwe, D., Ioannidis, P., Harrison, A.L., Mackenzie, C., Hilton, G.M., Nolet, B.A. & Rees, E.C. 2018. Apparent survival of an Arctic-breeding migratory bird over 44 years of fluctuating population size. Ibis 160: 413–430.

Wood, K.A., Brown, M.J., Cromie, R.L., Hilton, G.M., Mackenzie, C., Newth, J.L., Pain, D.J., Perrins, C.M. & Rees, E.C. 2019. Regulation of lead fishing weights results in Mute Swan population recovery. Biological Conservation 230: 67–74.