50 Taiga Bean Goose at Sarobetsu, Japan
©Wildfowl & Wetlands Trust
Wildfowl
(2013) 63: 40–55
last to leave. Red A3Z, for example,
appeared as early as 4 September and
remained until 11 October in 2004, but
arrived late (18 September) and remained
only until 1 October in 2005. Nor did late
arriving birds necessarily leave Sarobetsu
early. Red A5Z was first observed on 18
September, but remained until 24 October
in 2004. Red collared K22 was first observed
on 21 September and last observed on 26
October in 2003. There was no correlation
between arrival and departure dates among
these 79 birds (Spearman Rank
r
77
= 0.045,
n.s.). We also found no difference in the
lengths of stay between the geese that
occurred first in zone A and those that
occurred first in zone C (
U
= 171,
n
1
= 7,
n
2
= 48, n.s.). The former stayed in the
Sarobetsu area for 1–57 days (mean = 29 ±
9 days), and the latter for 1–64 days (mean =
33 ± 3 days). Among geese that occurred
first in zone A, red A6F stayed only eight
days in 2005, whereas red A5M remained for
44 days in 2002. Similarly, among those that
occurred first in zone C, A3Z stayed only
nine days in 2006 but 49 days in 2007. It is
clear that geese that occurred first in zone A
and left the Sarobetsu study area without
moving to zone C remained only a short
period of time,
e.g.
A5Z in 2002 (one day)
and A6F in 2005 (eight days) and in 2007
(two days). Nevertheless it is impossible to
establish a ratio of short-staying birds
within the total number of birds that
occurred first in zone A. Lengths of stay
varied significantly between individuals
(ANOVA:
F
12,66
= 4.86,
P
< 0.001); for
instance, A6F stayed for only short periods
(1–23 days,
n
= 5 years) each year, whereas
A5M (44–64 days,
n
= 6 years), K22 (35–59
days,
n
= 8 years), K34 (16–53 days,
n
= 7
years), and red P66 (18–55 days,
n
= 7 years,
with the exception of 2005 when it
remained only one day) were long-staying
visitors. Some individuals remained for
almost the whole season, such as K33 in
2004, when it stayed for 58 days during a
total staging period of 65 days. The mean
staging duration for these 13 banded geese
over the 8-year period was 29 days (s.e. = 2).
Duration of the spring staging period
The date on which the first Taiga Bean
Geese were seen each spring ranged from
late March (earliest arrival date = 27 March)
to early April (latest arrival date = 8 April).
The last day on which geese were known to
be present was in late April for the years
2002–2005 and in May from 2006 onwards:
four times in early May (2006, 2008, 2010
and 2011) and three times in mid May (2007,
2009 and 2012). The duration of the spring
staging period (
i.e
. geese known to be
present in the study area) ranged from 23
(2003) to 50 days (2009), with a mean length
of stay of 35 days (s.e. = 2), or about half
(46%) of the length of the autumn staging
period. The difference between autumn and
spring in the length of the staging period
was statistically significant (
U
= 5,
n
1
= 10,
n
2
= 11,
P
< 0.001).
Observations of banded geese (19
different individuals; total spring sightings
n
= 44), revealed that individuals stayed in the
Sarobetsu study area for at least 1–18 days
(mean = 4 ± 1 days) in spring, with most (40
geese; 91% of birds identified) remaining at
the site for < 10 days, indicating a rapid
movement of individuals through the site
during spring migration. Duration of
