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Tagging eider ducks

This project is entitled 'Nesting site choices of female eider ducks in Breiðafjörður – a long-term population study'. This is an annual long-term observation of tagged female eider ducks on the south side of Breiðafjörður fjord. The data is used to measure survival rates, nesting success and breeding-ground fidelity. Nesting time is evaluated using incubation-stage tests and the number of eggs is recorded. 

A total of 1030 female eider ducks have been tagged as part of this project and 688 of those have been re-captured at least once (2014-2020). Every year 100-200 ducks are captured and tens of coloured tags are read in addition. In 2014, ducks were tagged in Landey and Hjallsey, but in seven locations in 2015-2016 (Landey, Hjallsey, Stakksey, Þorvaldsey, Sellátur, Rifgirðingar and Elliðaey). Finally, four new islands were added in 2017: Bíldsey, Höskuldsey, Gimburey and Þormóðsey. 

The aims are to

  1. investigate whether the female eider ducks move between islands, i.e. demonstrate varying breeding ground fidelity between islands and between years.
  2. explain individual variability in choice of nesting site and nesting success.
  3. compare nesting success, egg-laying dates and incubation between the islands, which differ in terrain, vegetation, predators and other nesting bird species which affect the safety of the eider ducks.
  4. investigate whether nest fidelity increases with age in the tagged female birds.
Eider duck being tagged
Eider duck tag