52 Taiga Bean Goose at Sarobetsu, Japan
©Wildfowl & Wetlands Trust
Wildfowl
(2013) 63: 40–55
turnover of marked individuals through the
site, indicate that a high proportion of the
Taiga Bean Geese wintering in Japan (
c
. 9,000
individuals) use Sarobetsu as a staging area in
both autumn and spring. The movements of
marked geese suggest that the seasonal peak
numbers fall well short of the total numbers
migrating through the area. The shorter
migration period and more rapid passage of
individuals in spring suggests that there is
greater scope for the seasonal peak numbers
to underestimate total staging numbers in
spring than in autumn. In any event, it is
reasonable to conclude that the seasonal
peak numbers represent most of the
population wintering in Japan in autumn and
at least one-fifth of these birds in spring.
Sarobetsu therefore is not only a staging area
of prime importance in Hokkaido, but is of
considerable national and international
conservation significance. By supporting
c
.
10% of the global population (estimated at
70–80,000 birds; Delany & Scott 2006) it
easily meets Criterion 6 (i.e. regular
occurrence of > 1% of a biogeographic
population of a species or subspecies of
waterbird) required for designating a site
as a wetland of international importance
under the Ramsar Convention (Ramsar
Convention on Wetlands 2009).
In mild autumns, geese remain at
Sarobetsu at least until mid November, and
occasionally late into the month, but there
has been no obvious earlier or later
extension of autumn staging beyond the
main early September–late November
migration period in relation to local or
global climate change. As for springs, geese
use Sarobetsu for about one month, tending
to remain longer since 2006.
The Japanese population of Taiga Bean
Geese passes through not only Sarobetsu
but also Sorachi and either Iburi or Tokachi
on Hokkaido in autumn, to winter in
Honshu, mostly in Niigata Prefecture (
e.g.
Lake Fukushima) and in Miyagi Prefecture
(
e.g.
Lake Kabukuri) (Miyabayashi &
Mundkur 1999) (Fig. 1). In spring, geese
returning north from Honshu make their
first stop-over in Hokkaido in the Iburi
region. From Iburi, they move north to
Sorachi or northeast to Tokachi. The geese
using the Sorachi region are thought to
occur afterwards in the Sarobetsu area, but
no banded Taiga Bean Goose that visited
the Tokachi region has subsequently been
observed at Sarobetsu in spring.
Since the Sarobetsu staging area in
autumn seems to support almost the entire
Japanese wintering Taiga Bean Goose
population, and since in spring Sarobetsu
also supports very significant numbers, the
maintenance of their habitat in the area is
essential for their conservation. The three
autumn roosting sites – Lake Kabuto, Lake
Penke and the Teshio Oxbow Lakes –
are crucially important. The farmland
surrounding these roost sites is also of great
significance for feeding during staging.
Zone C, including Lake Penke and the
surrounding farmland, supports the geese
throughout the autumn staging season, and
numbers there are considerably greater than
in the other zones. At the beginning of the
autumn staging season Lake Kabuto and
adjacent pasture in zone A are as important
as zone C for the population. Although zone
E is used by fewer geese than zone C, it
constitutes an integral part of the Sarobetsu
staging area. These three zones are not
