HORSSEN P VAN & LENSINK R (2000) A rapid increase of the Bar-headed Goose Anser indicus in the Netherlands. LIMOSA 73 (3): 97-104.

Bar-headed Geese were first observed in the Netherlands in the 1950s en 1960s. They originated from escapes and introductions. In 1977 the first breeding pair was noticed. From 1986 onwards Bar-headed Geese bred every year, and the number increased since then with on average 11 % per year (Fig. 1). In 1999 the number of breeding pairs was estimated at 60-70. Most birds breed along the river Rhine/Lek, and at Nieuwkoop (Fig. 2). Those birds certainly originate from local introductions and have been recorded breeding there for at least seven years. At three other sites birds bred for seven years or longer, probably also after local introductions. Hatching of chicks occurred between 5 May and 28 June, with 24 May as median date (Fig. 3).

Outside the breeding season the number of Bar-headed Geese increased as weil, with on average 10% anually (Fig. 4). Along the river Rhine/Lek the rise in numbers was larger than along the other rivers. In winter, main concentrations were found near the breeding sites. Contrary to severe winters, during mild or moderate winters the number of geese along the rivers hardly decreases (Fig. 5). These patterns suggest a residenti al behaviour of this species, whereas it is a migrant in the original Asian distribution range. The seasonal pattern in the North of the country suggest a weak migration in autumn from Scandinavia towards West and SW Europe (Fig. 6). In most cases these birds were seen among northern Greylag Geese, which use the same migration route Bar-headed Goose Anser indicus

[free pdf] [dutch summary]