Taiga Bean Goose at Sarobetsu, Japan 51
©Wildfowl & Wetlands Trust
Wildfowl
(2013) 63: 40–55
staging was markedly shorter than in
autumn (when the mean staging period
was 29 ± 2 days) and the difference
was significant (
U
= 4,
n
1
= 13,
n
2
= 19,
P
< 0.001). Unlike during autumn staging,
no geese remained for most of the season.
Spatial distribution
Autumn distribution
Taiga Bean Geese occurred in zone C
throughout the autumn staging period each
year, with peak counts exceeding those of
the other four zones combined, confirming
zone C as the core zone within Sarobetsu
for the population in autumn (Fig. 5a). Zone
A was used mainly in early autumn,
particularly in early September when
numbers there often equalled those in zone
C (maximum September count = 2,072
birds, mean = 468 ± 94; Fig 5a), with no
geese encountered in only one 10-day period
out of 30 during 2002–2011. Zone A held a
maximum of 625 (mean = 53 ± 24) in
October, with no geese encountered in 17
10-day periods and in November held a
maximum of 86 (mean = 4 ± 3) with no
geese encountered in 28 10-day periods (Fig.
3a). Zone A therefore can be considered
as an auxiliary site within the Sarobetsu
staging area, but one that is of particular
importance at the beginning of the season.
In both 2010 and 2011, zone A attracted
considerably more geese than zone C in
early September, but it is too early to know
whether this represents a new trend or if
this was an irregular phenomenon. Geese
were found regularly in zone B whenever
geese were also present in zone C, but the
numbers there were always lower. Zone B
therefore is an important feeding area for
the geese, and can be considered as an
extension to zone A at the beginning of the
season and to zone C throughout the whole
season. Zone D was not used in autumn
during the study period. Although zone E
represents the southernmost part of the
study area, geese were observed there in
early September each year.
Spring distribution
In spring, zone D attracted more geese in
the early part of the season than did zone C
(Fig. 3b). Geese were found in zone D in late
March in five years (2002, 2007, 2008, 2009
and 2012) in comparison with only one year
(2008) in zone C, and the number of birds
using zone D was much greater than in zone
C (Fig. 5b). Zone D alone supported about
16% (mean = 1,427 ± 70) of the geese
wintering in Japan during the peak spring
migratory period. As the spring thaw
proceeds during April, snow and ice melt
enlarges the area of available open water, so
Lake Penke and the surrounding farmland
in zone C become increasingly attractive to
geese, but only after mid-month. Zone D
therefore is of prime importance for the
population until then. As the spring staging
season progresses, zone C attracts
increasing numbers of geese. The geese also
occur regularly in zone A in spring, but in
smaller numbers than in zone D. Goose use
of zone B was irregular in spring. Zone E
has attracted geese more and more regularly
from 2010 onward.
Discussion
The large numbers of geese counted (mean
annual maxima = 7,272 ± 267 in autumn;
2,048 ± 140 in spring), together with the
