Since the early 1980s, the Swan Specialist Group has monitored the NW-European Bewick’s Swan population carefully, to keep track on the population status and assess its conservation requirements. For this purpose, an international counts of the population size is organised once every five years (last in 2020) and productivity is assessed on an annual basis. This setup is important because historically the population size was small and, following an increase in numbers between the 1970s and mid-1990s, is now in decline and subject to major changes in winter distribution. Indeed, having peaked at just below 30,000 birds in 1995, numbers dropped to 18,100 in 2010. Whether a slight recovery to c. 20,100 birds in 2015 (Beekman et al. 2019) has been maintained hereafter remains to be seen, pending on the final results of the 2020-census. Age counts are an important tool for understanding such fluctuations in population size, along with results of ring-readings which give insight in survival and mortality patterns (and changes in migration strategy).