Climate change impacts migratory herbivorous waterbirds throughout the annual cycle by affecting resource availability, timing of movements, and ultimately their fitness. Using GPS tracking data and citizen science counts (2006–2025) we analyse climate-driven changes in wintering behaviour of Taiga Bean Geese ( Anser fabalis fabalis ) in Denmark. Arrival timing at Danish wintering grounds varied with abrupt cold spells at the autumn staging sites in Sweden but showed no long-term trend throughout the study period. The earlier onset of spring advanced departures from Denmark, while colder spring conditions delayed them. Progressive climate warming has generally advanced spring onset, resulting in a trend of earlier departure timing through the study period, causing a shortened length of stay at the Danish wintering grounds over time. During cold spells, individuals shifted from the main wintering area to cold-weather refuges, returning to the main site once conditions became mild. These within-winter movements highlight the need for a suitable network of sites fulfilling changing energetic demands during winter. Our results show that short- and long-term temperature changes affect migration timing and within-winter movements of conservation-focused Taiga Bean Geese and suggest their ability to adapt to climatic changes in their staging and wintering ranges.
Vergin et al. (Fri,) studied this question.