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Declines amongst breeding Eider Somateria mollissima numbers in the Baltic/Wadden Sea flyway

Ekroos, Johan; Fox, Anthony D.; Christensen, Thomas K.; Petersen, Ib K.; Kilpi, Mikael; Jonsson, Jon E.; Green, Martin LU ; Laursen, Karsten; Cervencl, Anja and de Boer, Peter, et al. (2012) In Ornis Fennica 89(2). p.81-90
Abstract
We report on the status of the Baltic/Wadden Sea flyway Eider population based on trends in breeding and wintering numbers throughout the region, supplemented by changes in the sex ratio and proportion of young Eiders as monitored in the Danish hunting bag. At the flyway scale, total numbers of breeding pairs decreased by 48% during 2000-2009, after relatively stable breeding numbers in 1991-2000. The majority of the population nest in Finland and Sweden, where the number of breeding pairs has halved over the same period. After initial declines in winter numbers between 1991 and 2000, during 2000-2009, national wintering numbers increased in the Baltic Sea, but decreased in the Wadden Sea. The annual proportion of adult females in the... (More)
We report on the status of the Baltic/Wadden Sea flyway Eider population based on trends in breeding and wintering numbers throughout the region, supplemented by changes in the sex ratio and proportion of young Eiders as monitored in the Danish hunting bag. At the flyway scale, total numbers of breeding pairs decreased by 48% during 2000-2009, after relatively stable breeding numbers in 1991-2000. The majority of the population nest in Finland and Sweden, where the number of breeding pairs has halved over the same period. After initial declines in winter numbers between 1991 and 2000, during 2000-2009, national wintering numbers increased in the Baltic Sea, but decreased in the Wadden Sea. The annual proportion of adult females in the Danish hunting bag data decreased from ca. 45% (1982) to ca. 25% (2009) and simultaneously the proportion of first-winter birds fell from ca. 70% to ca. 30%, indicating dramatic structural changes in the Danish wintering numbers. These results suggest that the total flyway population will experience further declines, unless productivity increases and the factors responsible for decreasing adult female survival are identified and ameliorated. We discuss potential population drivers and present some recommendations for improved flyway-level monitoring and management of Eiders. (Less)
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type
Contribution to journal
publication status
published
subject
in
Ornis Fennica
volume
89
issue
2
pages
81 - 90
publisher
BirdLife Finland
external identifiers
  • wos:000305671500001
  • scopus:84862125460
ISSN
0030-5685
project
BECC
language
English
LU publication?
yes
id
f39e1427-73e4-427d-8589-e378ea24365a (old id 2883767)
date added to LUP
2012-07-24 15:52:00
date last changed
2017-11-12 03:40:16
@article{f39e1427-73e4-427d-8589-e378ea24365a,
  abstract     = {We report on the status of the Baltic/Wadden Sea flyway Eider population based on trends in breeding and wintering numbers throughout the region, supplemented by changes in the sex ratio and proportion of young Eiders as monitored in the Danish hunting bag. At the flyway scale, total numbers of breeding pairs decreased by 48% during 2000-2009, after relatively stable breeding numbers in 1991-2000. The majority of the population nest in Finland and Sweden, where the number of breeding pairs has halved over the same period. After initial declines in winter numbers between 1991 and 2000, during 2000-2009, national wintering numbers increased in the Baltic Sea, but decreased in the Wadden Sea. The annual proportion of adult females in the Danish hunting bag data decreased from ca. 45% (1982) to ca. 25% (2009) and simultaneously the proportion of first-winter birds fell from ca. 70% to ca. 30%, indicating dramatic structural changes in the Danish wintering numbers. These results suggest that the total flyway population will experience further declines, unless productivity increases and the factors responsible for decreasing adult female survival are identified and ameliorated. We discuss potential population drivers and present some recommendations for improved flyway-level monitoring and management of Eiders.},
  author       = {Ekroos, Johan and Fox, Anthony D. and Christensen, Thomas K. and Petersen, Ib K. and Kilpi, Mikael and Jonsson, Jon E. and Green, Martin and Laursen, Karsten and Cervencl, Anja and de Boer, Peter and Nilsson, Leif and Meissner, Wlodzimierz and Garthe, Stefan and Ost, Markus},
  issn         = {0030-5685},
  language     = {eng},
  number       = {2},
  pages        = {81--90},
  publisher    = {BirdLife Finland},
  series       = {Ornis Fennica},
  title        = {Declines amongst breeding Eider Somateria mollissima numbers in the Baltic/Wadden Sea flyway},
  volume       = {89},
  year         = {2012},
}