AtlanticSwans: From individual movement to population distribution

Bewick’s swans breed on the Russian tundra and the European population winters in the North Sea countries. Ring-resightings of Bewick’s swans have shown a >500 km eastward shift in wintering range, and a shortening of their wintering period of >1 month over the last 50 years. These changes were measurable both at the population level and at the individual level, suggesting a combination of generational effects and individual plasticity as the main processes. In this project we will try to obtain a more mechanistic understanding of the reported changes in the timing of arrival at and departure from the wintering range, as well as the changes in the location and extent of the wintering range itself. We will use a combination of GPS tracking, analyses of tracking and resighting data, and modelling. Movement rules will be derived from ecological and behavioural mechanisms and physiological constraints, and implemented in an IBM. Next, the IBM will be used to simulate population distributions. The resighting data, corrected for observer bias, will be used to arrive at the ‘observed’ population distribution. Simulated and ‘observed’ population distributions will finally be compared.