Leeftijdstellingen bij de Kolgans Anser albifrons

Age-ratio counts of Greater White-fronted Geese have been undertaken since the end of the 1950s. Some conclusions are: – percentages of first-winter birds and the size of the wintering population in the Netherlands show relations. Many juveniles result in a larger population and reversed. Sometimes the relation is less than might be anticipated. Other factors must influence the numbers of wintering Greater White-fronted Geese (Table 1); – percentages of first-winter birds in different parts of the Netherlands mostly correspond fairly well. Exceptions occur however (Tables 2, 3 and 4); – percentages of juveniles remain rather stable in the course of the winter season in most cases (Table 5); – if the counts are made under good conditions (good light, favourable weather, distance not too far), they are sufficiently reliable.