LENSINK R (1999) Do White-fronted Geese Anser albifrons arrive earlier and earlier?. LIMOSA 72 (3): 104-105.

Since 1981, autumn migration has been recorded almost daily at a site near Arnhem. Observations were made in the early morning only, from the beginning of August till the end of November. In 1981-98 the number of Whitefronted Geese increased from nearly absent in the first seven years up to several hundreds thereafter and more than 1000 in 1998 (Fig. 1). In the meantime, observation of the first flocks shifted towards the first half of October (Fig. 2). This pattern reflects the earlier arrival of Whitefronted Geese in The Netherlands in the 1990s.

[free pdf] [dutch summary]