VOSLAMBER B, JEUGD H VAN DER & KOFFIJBERG K (2007) Numbers, trends and distribution of breeding goose populations in the Netherlands. LIMOSA 80 (1): 1-17.
In the past two decades, breeding geese have expanded
rapidly in The Netherlands. A national survey in 2005 revealed
a total number of nearly 40,000 breeding pairs
and 155,500 individuals including non-breeders (but not
moulting Greylag Geese from abroad; Tab. 1, Fig. 1). The
majority are Greylag Geese Anser anser (25,000 pairs,
100,000 individuals). Since its re-introduction in 1961 (after
extinction in the early 20th century), the population
has shown an annual increase of 20% (Fig. 4). Today, it is
distributed over major parts of the country (Fig. 5).
Meanwhile, also Feral Geese A. anser f. domestica have
started to breed, but in much smaller numbers (3700-
5000 pairs) and with a lower rate of increase, due to generally
poor breeding success. Counts in winter suggest
an overall population of 15,000 birds. Barnacle Goose
Branta leucopsis (6000 pairs) has shown an annual increase
of 46% since the first breeding attempt in 1982
(Fig. 12), the highest growth rate observed in any goose
population. Core breeding areas are situated in embanked
estuaries in the northern part of the Delta area
(Fig. 13), where also large flocks gather to moult in summer.
At least some small populations originate from escaped
or abandoned breeding pairs from parks, but the
origin of the large Delta population is not entirely clear.
The increase in the Netherlands follows westward expansion
of the Russian breeding areas and establishment
of a large breeding population in the Baltic.
Recoveries of marked individuals have demonstrated
exchange of birds between the Russian, Baltic and
North Sea populations, and we therefore consider
Barnacle Geese a native breeding bird in The Nether -
lands. The introduced Greater Canada Goose B. cana densis
is expanding rapidly from its core breeding areas in
the SW Netherlands (Fig. 8,9). Sightings of ringed birds
have revealed movements between the Netherlands
and western Germany and northern Belgium, including
moult movements (Fig. 11). Hutchins'
B. hutchinsii is an introduced species restricted to a few
breeding sites. The same applies to Greater-White fronted
Geese, assumed to originate mainly from live decoys
abandoned in the late 1980s. Numbers are still quite low
(Fig. 2) and breeding success seems poor. Introduced
Bar-headed Goose increased by 20% annually since
1972 but today, numbers seem to be fairly stable at 100
breeding pairs (350 individuals). Other species listed in
Table 1 are considered introduced too, but breeding has
not been proven yet or numbers are below 10 pairs.
The increase in breeding goose populations in the
Netherlands coincides with a general increase in many
NW-European countries and a southward expansion of
the arctic breeding areas of some species, notably
Barnacle Goose. Changes in agricultural practice that
have improved feeding conditions, along with a lower
hunting pressure, are considered the main driving
forces behind the growing goose numbers, both in arctic
and temperate breeding areas (Fig. 14). Similar developments
have been observed in Nearctic goose populations.
Additionally, breeding geese in The Netherlands
have benefited from the creation of wetlands and recent
embankments. Especially Greylag Goose has expanded
rapidly in small wetlands found scattered
through the country, even in park-like suburban areas.
Often, food is limited in such areas, but due to the proximity
to attractive food resources in the surrounding
agricultural areas, geese have found a perfect breeding
habitat. Breeding of Barnacle Geese in the Delta area,
SW-Netherlands, was facilitated by the embankment of
the Krammer-Volkerak in 1987 and the grazing of large
nature reserves with livestock. Here, islands provide safe
breeding places and families and non-breeding flocks
feed in the grazed areas.
Population models using demographic parameters and
amount of available habitat predict that the increase will
continue in the years to come. So far, only some long-established
Greylag Goose populations show signs of saturation,
but as unoccupied breeding habitat is still available
in several parts of the country, the population
might increase further to a level of perhaps 60,000-
90,000 pairs, if predation, competition with other species
and population control measures are not taken into account.
Greater Canada Goose might grow to 40-60,000
pairs, at the expense of Greylag Goose that would be expected
to reach at most 38,000 pairs in this scenario, and
become the second-abundant breeding goose species.
Barnacle Geese might be less successful due to their
coloniality and dependence on islands for safe breeding.
Many colonies in the Baltic have already suffered high
predation rates by Red Fox Vulpes vulpes, a phenomenon
which might also constrain further population expansion
in The Netherlands, especially when fox numbers in
the core breeding areas are allowed to increase.
[free pdf] [dutch summary]