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Long-term population trends and shifts in distribution of Bewick's swans cygnus columbianus bewickii wintering in northwest Europe

Beekman, Jan ; Koffijberg, Kees ; Wahl, Johannes ; Kowallik, Christine ; Hall, Colette ; Devos, Koen ; Clausen, Preben ; Hornman, Menno ; Laubek, Bjarke and Luigujõe, Leho , et al. (2020) In Wildfowl p.73-102
Abstract

Coordinated international censuses of the Northwest European Bewick's Swan Cygnus columbianus bewickii population have been undertaken across the swans' wintering range at c. 5-year intervals since 1984. During the early years of the study, numbers increased steadily to a peak of 29,780 individuals in January 1995, but then declined by 39.4% to 18,057 swans counted in January 2010 before showing a partial recovery to 20,149 recorded in January 2015. Changes in distribution across the wintering range were also recorded; a higher proportion of the population now remains in more easterly countries (notably Germany) in mid-winter, whilst only a handful of birds migrated to Ireland (at the western edge of the range) during the 2000s compared... (More)

Coordinated international censuses of the Northwest European Bewick's Swan Cygnus columbianus bewickii population have been undertaken across the swans' wintering range at c. 5-year intervals since 1984. During the early years of the study, numbers increased steadily to a peak of 29,780 individuals in January 1995, but then declined by 39.4% to 18,057 swans counted in January 2010 before showing a partial recovery to 20,149 recorded in January 2015. Changes in distribution across the wintering range were also recorded; a higher proportion of the population now remains in more easterly countries (notably Germany) in mid-winter, whilst only a handful of birds migrated to Ireland (at the western edge of the range) during the 2000s compared to >1,000 wintering there at the start of the study. Variation between censuses in the proportion of swans recorded in different parts of the range were attributable to weather conditions, with more swans wintering further north in warmer years. The overall percentage of cygnets recorded in each of the census years ranged from 9.6% in 2010 to 13.2% in 2005, with no obvious consistency over time in the distribution of cygnets across the wintering range. There were however changes between 1990 and 2015 in the swans' use of feeding habitats, with a decline in the proportion of birds on pasture and a corresponding increase in those on arable land. Decreases in the total population size and changes in distribution in the 21st century have implications for the designation and resultant protection of sites of international importance for the species.

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organization
publishing date
type
Contribution to journal
publication status
published
subject
keywords
Habitat use, Population increase and decline, Short-stopping, Species threshold levels, Weather conditions
in
Wildfowl
issue
69
pages
30 pages
publisher
Wildfowl and Wetlands Trust
external identifiers
  • scopus:85082875100
ISSN
0954-6324
language
English
LU publication?
yes
id
2198a698-d5d3-4adb-bf31-f8328e5d0ddd
date added to LUP
2020-12-18 12:41:45
date last changed
2021-03-24 02:28:28
@article{2198a698-d5d3-4adb-bf31-f8328e5d0ddd,
  abstract     = {<p>Coordinated international censuses of the Northwest European Bewick's Swan Cygnus columbianus bewickii population have been undertaken across the swans' wintering range at c. 5-year intervals since 1984. During the early years of the study, numbers increased steadily to a peak of 29,780 individuals in January 1995, but then declined by 39.4% to 18,057 swans counted in January 2010 before showing a partial recovery to 20,149 recorded in January 2015. Changes in distribution across the wintering range were also recorded; a higher proportion of the population now remains in more easterly countries (notably Germany) in mid-winter, whilst only a handful of birds migrated to Ireland (at the western edge of the range) during the 2000s compared to &gt;1,000 wintering there at the start of the study. Variation between censuses in the proportion of swans recorded in different parts of the range were attributable to weather conditions, with more swans wintering further north in warmer years. The overall percentage of cygnets recorded in each of the census years ranged from 9.6% in 2010 to 13.2% in 2005, with no obvious consistency over time in the distribution of cygnets across the wintering range. There were however changes between 1990 and 2015 in the swans' use of feeding habitats, with a decline in the proportion of birds on pasture and a corresponding increase in those on arable land. Decreases in the total population size and changes in distribution in the 21st century have implications for the designation and resultant protection of sites of international importance for the species.</p>},
  author       = {Beekman, Jan and Koffijberg, Kees and Wahl, Johannes and Kowallik, Christine and Hall, Colette and Devos, Koen and Clausen, Preben and Hornman, Menno and Laubek, Bjarke and Luigujõe, Leho and Wieloch, Maria and Boland, Helen and Švažas, Saulius and Nilsson, Leif and Stipniece, Antra and Keller, Verena and Gaudard, Clémence and Degen, Axel and Shimmings, Paul and Larsen, Bjørn Harald and Portolou, Danae and Langendoen, Tom and Wood, Kevin A. and Rees, Eileen C.},
  issn         = {0954-6324},
  language     = {eng},
  number       = {69},
  pages        = {73--102},
  publisher    = {Wildfowl and Wetlands Trust},
  series       = {Wildfowl},
  title        = {Long-term population trends and shifts in distribution of Bewick's swans cygnus columbianus bewickii wintering in northwest Europe},
  year         = {2020},
}