Pre-nesting site use of satellite transmitter tagged Svalbard
Pink-footed Geese Anser brachyrhynchus
Christian M. Glahder1,*, Tony (A.D.) Fox2, Christiane E. Hübner3,
Jesper Madsen1 & Ingunn M. Tombre4
Glahder C.M., Fox A.D., Hübner C.E., Madsen J. & Tombre I.M. 2006.
Pre-nesting site use of satellite transmitter tagged Svalbard Pink-footed
Geese Anser brachyrhynchus. Ardea 94(3): 679–690.
We deployed satellite transmitters (PTTs) on Pink-footed Geese Anser
brachyrhynchus to discover pre-nesting sites on Svalbard. 14 adult male
were caught in Vest Stadil Fjord, Denmark and fitted with PTTs powered
by batteries (n = 11; 30 g) or by solar power (n = 3; 45 g), March 2003
and 2004. All geese staged in the Trondheim Fjord area, mid Norway,
for 2–3 weeks before onward migration to Vesterålen, north Norway,
where average arrival and departure dates were 10 and 17 May 2003
and 15 and 19 May 2004. Average staging period in Vesterålen of satellite tagged geese was 4–6 days. No staging areas were identified
between Vesterålen and Svalbard. Average arrival dates in Svalbard
were 22 May 2003 and 21 May 2004. On arrival to Svalbard geese
staged in southwestern coastal areas of Spitsbergen (n = 5) and around
Isfjord, central Spitsbergen (n = 6), areas which tend to thaw early in
spring. Geese staged on average at two staging areas before 1 June during a total staging period of about 8 days. First egg dates in the two
years in Sassendalen, central Spitsbergen, were mainly between 26 and
31 May, so tagged geese should have arrived at their breeding areas
before 1 June. Therefore, rapid follicular development must be initiated
in Vesterålen, confirmed by observations of oocyte development in birds
shot on arrival in Svalbard. A pre-nesting increase in male abdominal
profile indices in Svalbard indicates income feeding as a supplement to
the capital invested in follicular growth on migration. We here present
the first and most comprehensive study on the distribution of pre-nesting sites on Svalbard and staging periods of the geese. Such habitats can
have a substantial influence on the reproductive success.
Key words: Anser brachyrhynchus, pink-footed geese, pre-nesting, satellite transmitters, staging periods, Svalbard, capital breeding
1National
Environmental Research Institute, University of Aarhus,
Department of Arctic Environment, Frederiksborgvej 399, P.O. Box 358,
DK-4000 Roskilde, Denmark; 2National Environmental Research
Institute, University of Aarhus, Department of Wildlife Ecology and
Biodiversity, Kalø, Grenåvej 12, DK-8410 Rønde, Denmark;
3
UNIS, The University Centre in Svalbard, PB 156, N-9171
Longyearbyen, Norway; 4Norwegian Institute for Nature Research,
NINA, Division of Arctic Ecology, the Polar Environmental Centre, N9296 Tromsø, Norway;
*corresponding author ([email protected])
680
ARDEA 94(3), 2006
INTRODUCTION
The Pink-footed Goose Anser brachyrhynchus population that breeds in Svalbard migrates through
Norway to winter in Denmark, the Netherlands
and Belgium. The population has increased
steadily from c. 15 000 in the 1960s to over 40
000 at present (Madsen et al. 1999 and unpubl.
data). A consequence of the population increase
has been intensive scaring of the geese on pastures
in north and mid-Norway (Tombre et al. 2005b,
Klaassen et al. 2006). Organised scaring may
adversely affect reproductive output and signs of
decreased annual breeding success have been
observed (Klaassen et al. 2006). To provide appropriate nature conservation management strategies
to safeguard the population, we need to understand habitat requirements during spring migration and factors that might limit population size.
Research attention has focussed on identifying
those periods and events in the annual cycle that
limit survival and reproductive output.
Foremost amongst these events are spring
migration and the pre-nesting period on the breeding grounds. Pink-footed Geese fly 550 km from
mid Norway staging areas in Trondheim Fjord to
Vesterålen in northern Norway (Fig. 1). From
Vesterålen birds fly c. 1100 km across the sea to
Svalbard (Madsen et al. 1999). The timing of
migration and use of these two staging areas is
well known from many years of study (Madsen et
al. 1999), but little is known about the migration
chronology of individual birds between staging
and breeding areas. Several other species of arctic
geese are known to stage at arrival areas before
moving to breeding areas (e.g. Glahder 1999a,b,
Glahder et al. 1999, Hübner 2006), and it is
expected that Pink-footed Geese may show similar
behaviour within Svalbard. Given the significance
of spring staging and pre-nesting feeding to the
nutrient status of breeding birds, especially breeding females, conditions at such habitats can have a
substantial influence on reproductive success
(Mainguy et al. 2002). Therefore, it is important to
know the number, distribution and extent of
spring staging sites used by a goose population,
78°N
Svalbard
Bjørnøya
74°N
69°N
Vesterålen
64°N
Trondheim Fjord
200 km
Figure 1. Spring migration routes and staging areas from
Trondheim Fjord, mid Norway to Svalbard used by Pinkfooted Geese attached with satellite transmitters. Each
dot represents a position of one of the 14 geese received
during May–June 2003 and 2004. Selected latitudes in
°N are shown.
the average staging period and numbers of birds
using such sites. This will provide information necessary to conserve and protect key Pink-footed
Goose staging habitats. Although numbers may
vary with season (for example due to annual differences in patterns of thaw), this also contributes
to our greater understanding by showing how
Glahder et al.: PRE-NESTING SITE USE OF PINK-FOOTED GEESE
geese can switch between different sites in response to such patterns.
In this paper, we used PTTs to study the timing
and duration of spring migration and stopover
sites in Svalbard Pink-footed Geese from the last
staging areas on Vesterålen to the breeding and
summering areas within Svalbard. The objectives
were to discover pre-nesting areas on Svalbard,
their distribution, approximate size and duration
of staging geese. Moreover, we examined the overall speed of migration, contrast differences
between individuals and speculate upon how
geese make decisions to move onwards along the
flyway corridor.
METHODS
Satellite telemetry
PTTs were attached to 14 adult male Pink-footed
Geese Anser brachyrhynchus (7 in March 2003 and
7 in March 2004) cannon-netted over bait at Vest
Stadil Fjord, Denmark (56°12'N, 08°08'E). Adult
males in good body condition (average weight
2871 g, SD 172 g) lacking shotgun pellets in the
body (geese were x-rayed during handling; one
goose in 2003 contained two pellets) were
selected both as robust individuals and to avoid
potential effects on female breeding performance
(Ward & Flint 1995). Each goose was marked
with a blue neck collar engraved with a threesymbol code to enable recognition in the field.
The PTTs (Microwave Telemetry, Inc.) were either
30 g battery powered (n = 11) or 45 g solar powered (n = 3: B6V, B8B, C1T; attached in 2004;
Fig. 2). All 14 transmitters were back-mounted,
glued and either secured by knicker elastic harnesses (Glahder et al. 1997) or with teflon ribbons (the three solar powered PTTs; R. Malecki,
pers. comm.). The 30 g transmitters were programmed to transmit for 8 hours and to ‘rest’ for
15 hours (79 cycles ≈ 1 April–15 June), 159
hours (11 cycles ≈ 16 June – 31 August) or 111
hours (until the end of battery power). The solar
powered PTTs were programm-ed to transmit for
10 hours and ‘rest’ for 21 hours. Signals sent every
681
60 seconds contained data on temperature, battery
voltage and goose movement. Transmissions were
received by polar orbiting NOAA satellites and
timed positions (UTC) were calculated by Argos
and assigned to different accuracy classes (Argos
CLS 1996, Fox et al. 2003). Positions were filtered
using an Argos Filter V5.0 SAS-program developed
by Dave Douglas, USGS, Alaska Science Centre,
USA. With this program we excluded locations in
the poorest quality classes (< class 1) unless their
locations were within 5 km of a previous or subsequent location.
Staging areas, duration and timing
For each staging area 50% and 90% dispersion
ranges were calculated as harmonic means (with
outliers removed and cell sizes optimised) (Dixon
& Chapman 1980) using ‘Range Manager’ (1998
Data Solutions, a MapInfo Professional application, http://solutionsGroup.tripod.com). The size
of the dispersion range is a function of (1) the
movements of the goose and (2) position inaccuracy, i.e. the difference between the true location
and the position derived from the calculated location. To assess the contribution of such inaccuracy,
dispersion ranges were calculated for two transmitters showing no goose movement (i.e. where
the goose had succumbed or the transmitter had
dropped off). A staging area was defined as an
area used by the goose immediately after arrival
on Svalbard and before arrival on the breeding
area (not later than 1 June, see below). A staging
area was described by at least eight valid positions, and if more than one staging area was used
by the goose no overlap was accepted between
50% dispersion ranges.
Minimum staging periods were calculated for
each location by subtracting the time from first
position from that of the last position. Because of
the programmed ‘resting’ periods between 15 and
21 hours during May and June, the real staging
period can potentially be up to 42 hours longer
than estimated.
From the satellite data it has not been possible
to determine precisely when a goose arrived on its
breeding area. For example, it was not possible to
682
ARDEA 94(3), 2006
differentiate between a goose using the same prebreeding and breeding area, or a goose that has
failed to breed, and moved to other habitats. Separate studies on nesting behaviour performed in
2003 and 2004 in Sassendalen, central Spitsbergen
(Fig. 6), showed that first egg in most nests was
laid 26–31 May. Therefore we arbitrarily defined
the end of the pre-breeding period as 1 June.
Body condition during last leg of
spring migration
Abdominal profile indices, APIs, provide a reliable
field index of body fat depots for geese (Madsen &
Klaassen 2006), in the pre-nesting period for male
geese only. Consequently, male Pink-footed Geese
were abdominally scored at different localities by
different observers during spring 2003 and 2004.
All observers used a standard set of drawings of
Pinkfeet APIs ranging from 1 (lean) to 7 (fat).
During the spring in Vesterålen, N Norway, a team
of observers regularly scanned geese at the most
important staging areas (Fig. 4) for neck-collared
birds. Observations were entered into a database
of ringed Pink-footed geese (www.pinkfoot.dmu.
dk) including data on date, time, position and API
scores. For geese fitted with satellite transmitters
we chose the latest API reading prior to departure
as departure state during 12–22 May 2003 and
14–19 May 2004, respectively. These two departure periods were used to calculate APIs for the
remainder of the males to compare conditions of
satellite tagged geese with those of untagged
geese. In Svalbard API was scored at Vårsolbukta
(southwestern Spitsbergen) and at Adventdalen
and Sassendalen (central Spitsbergen). At Vårsolbukta, neck-collared birds were scanned for and
APIs were scored from first arrival onwards (11
May – 14 June 2003; 7 May – 14 June 2004). API
readings in Adventdalen were performed several
times each day during 20–24 May 2003 and 14–28
May 2004. Since the transmitter fitted geese
arrived in Svalbard during 17–23 May 2004, an
average API was calculated for this period only. In
Sassendalen, APIs were scored for early breeding
males in two different breeding areas during
26–31 May 2003 and on 28 and 29 May 2004.
C1T
B8B
B6V
B6K
B5F
B1Z
B1J
A5E
A4Z
A4T
A4H
A4E
A3G
A2F
0
5
10
15
20
25
30
35
days from 25 April
prior to Vesterålen
Vesterålen
migration to Svalbard
1st stage Svalbard
2nd stage Svalbard
3rd stage Svalbard
4th stage Svalbard
Figure 2. Timing of spring migration and staging between Vesterålen, north Norway and Svalbard of 13 Pinkfooted Geese attached with satellite transmitters in 2003
and 2004. The duration (days) of migration and staging
from 25 April to 1 June is shown for each goose identified by a neck-collar code (left axis). The transmitter on
the 14th goose (B8B) showed no activity from a position
c. 100 km N of Trondheim Fjord.
Weather conditions
Mean May and June temperatures on Svalbard in
both 2003 and 2004 were 1–2°C higher than normal and precipitation during the same period was
below normal (all month <11 mm). In Northern
Norway, May temperatures in 2003 were above
normal while Mid Norway had normal to slightly
colder temperatures. May 2004 temperatures were
above normal throughout mainland Norway (all
data from www.met.no).
RESULTS
Migration and staging from Vesterålen to Svalbard
All geese fitted with a satellite transmitter in Denmark migrated to Trondheim Fjord, mid Norway,
683
Glahder et al.: PRE-NESTING SITE USE OF PINK-FOOTED GEESE
Table 1. Staging periods and 50% dispersion ranges for satellite-tagged Pink-footed Geese on Vesterålen and Svalbard.
Staging periods on Svalbard are shown from arrival to 1 June for individual satellite-tagged geese at different staging
areas and dispersion ranges. Staging periods on Svalbard given in italics indicate first staging periods. Is = Isfjord area,
SW = SW coast of Spitsbergen. Blank areas indicate no staging or fewer staging areas than on either Vesterålen or
Svalbard. No ranges were calculated when too few positions were available.
Code
Year
A2F
2003
2003
2003
2003
2003
2003
2003
2003
2003
2003
2003
2003
2003
2003
2003
A3G
A4E
A4H
A4T
A5E
Average
SD
B1J
B1Z
B5F
B6K
B6V
C1T
Average
SD
2004
2004
2004
2004
2004
2004
2004
2004
2004
2004
2004
2004
Vesterålen
Period (days)
Range (km2)
2.0
0.2
8.7
3.5
10.3
2.1
2.9
3.0
0
5.4
78.5
31.6
9.2
11.8
42.2
42.2
35.8
15.8
3.3
20.9
3.8
3.2
32.0
21.5
3.2
42.9
1.2
4.1
0.1
1.1
0.2
13.8
18.8
5.3
1.2
4.5
28.7
2.3
2.0
19.1
12.7
13.9
8.3
7.1
and 11 continued to Vesterålen, north Norway
(Figs 1 and 2, Table 1). Two geese migrated directly to Svalbard from Trondheim Fjord (B1J, A4T),
one of them with a brief (few hours) stop in
Vesterålen (Fig. 2, Table 1). The last goose (B8B)
either lost the transmitter or succumbed about 100
km north of Trondheim Fjord. In 2003, signals
were lost from two geese during their crossing
Svalbard
Period (days)
Range (km2)
1.3
4.5
26.9
42.4
1.2
1.3
8.6
8.8
7.4
2.0
0.4
10.1
19.5
7.4
10.4
19.5
12.8
23.5
7.6
20.1
4.6
3.8
19.0
10.6
Veslebukta (SW)
Dicksonfjord (Is)
Ekmanfjord
Elveflya (SW)
3.5
2.2
7.2
4.7
10.7
14.1
11.9
28.3
Hornsundneset (SW)
Adventdalen, outer
Adventdalen, inner
Adventdalen, outer
Frysjaodden (SW)
Reinsdyrflya
Isbjørnehamna (SW)
4.3
0.3
5.7
0.2
5.5
0.5
8.6
7.5
25.5
6.2
25.5
41.1
21.2
12.1
3.9
2.9
18.6
10.7
Area
Colesdalen (Is)
Dicksonfjord
Adventdalen (Is)
Deltaneset
Diabasodden
Ingertreodden (Is)
Adventdalen (Is)
Nordfjord W
Elveneset
Sassendalen (Is)
from Vesterålen to Svalbard (A4E, 14 May west off
Spitsbergen; A3G, 17 May southwest of Bjørnøya).
In 2004, two geese reached the southwestern coast
of Spitsbergen whereupon signals were received
from non-moving transmitters (B5F, last position
on 26 May; B1J, last position on 22 May, Fig. 6).
The maximum migration period from Vesterålen to
Svalbard (i.e. subtracting the time for last position
ARDEA 94(3), 2006
in Vesterålen from that of first position on
Svalbard) was on average 2.2 days (± 1.1 SD, n =
12). Just one goose (B1Z) staged on Bjørnøya for
2–7 hours. Another goose (B6V) could theoretically have staged on the island for maximal 40
hours, but we have data only from Vesterålen and
Svalbard. Three geese (A2F, A5E, B1J) were sitting
on the water or an ice floe well off Bjørnøya for a
maximum of 2–28 hours. Overall, geese staged in
Svalbard at 1–4 staging areas prior to 1 June.
16
2003
2004
14
total goose number (x1000)
684
12
10
8
6
4
2
Staging areas and periods in Vesterålen
The average arrival and departure dates of
transmitter attached geese in Vesterålen the two
years were 10 and 17 May 2003 and 15 and 19
May 2004, which corresponded well to the period
of peak numbers counted on Langøya the two
years (Fig. 3).
In Vesterålen, transmitter tagged geese used an
average of 1.7 staging areas in the two years. The
average staging period on each staging area was
3.8 days (± 3.2, n = 11, 2003) and 2.3 days
(± 2.0, n = 9, 2004) (Fig. 4, Table 1). Overall, the
average staging period for each satellite tagged
goose in Vesterålen was 5.9 days (± 5.7, n = 7,
2003) and 4.2 days (± 2.0, n = 5, 2004). For
comparison, all observed neck-collared male geese
the two years staged on average 3.8 days (± 3.9,
n = 193, 2003) and 3.6 days (± 4.4, n = 287,
2004). These periods are slightly shorter than
those derived from the satellite transmitter data,
but if we select the observed collared birds carrying a transmitter then the staging periods the two
years were on average 5.3 days (± 5.6, n = 7,
2003) and 4.2 days (± 3.1, n = 5, 2004). There
were no significant differences in staging period of
neck-collared males with or without attached
transmitters in any of the two years (t-test: P >
0.10, t198 = 1.00 (2003); P > 0.10, t290 = 0.30
(2004)).
Most geese staged on Langøya, fewer on Andøya
(Fig. 4). Dispersion ranges in 2003 did not differ
significantly from those in 2004 (t-tests 50% range
P = 0.182, df = 14; 90% range P = 0.161, df =
13). Dispersion ranges of two inactive transmitters
in 2004 (50%: 4.6 and 15.0 km2, 90%: 34.1 and
0
12
16
20
April
24
28
2
6
10
14
18
22
26
May
Figure 3. Arrival and departure dates of satellite-tagged
Pink-footed Geese staging in Vesterålen during spring
2003 and 2004 compared to local abundance of geese in
both years. Total daily maximum numbers counted on
Langøya, Vesterålen are shown in the histogram columns.
Inserted are the arrival (triangle, pointing downwards)
and departure (triangle, pointing upwards) dates for individual satellite-tagged geese, and horizontal bars show
average staging periods for these birds for the two years.
54.2 km2) were not significantly different from
ranges of transmitters attached to moving geese
from the same year (t-tests 50% range P = 0.372,
df = 7; 90% range P = 0.553, df = 6).
Svalbard staging areas and periods
The average arrival dates of transmitter tagged
geese in Svalbard in the two years were 22 May
2003 (range 19–25 May, n = 5) and 21 May 2004
(range 17–23 May, n = 6). This corresponded well
with peak numbers counted at Vårsolbukta and
Hyttevik (SW Spitsbergen) and in Adventdalen
(central Spitsbergen) (Fig. 5).
On arrival in Svalbard, transmitter tagged
geese staged either on the south-west coast of
Spitsbergen (n = 5) or in the Isfjord area in central Spitsbergen (n = 6) (Fig. 6, Table 1). There
was no difference between average staging periods
in the two main arrival areas (SW coast: 5.3 days,
± 2.0, n = 5; Isfjord: 5.2 days, ± 4.1, n = 6) and
the average period spent at the first staging area
685
Glahder et al.: PRE-NESTING SITE USE OF PINK-FOOTED GEESE
N
Andøya
Langøya
10 km
Figure 4. Dispersion ranges (50%) on Vesterålen of 11 Pink-footed geese attached with satellite transmitters 2003
(solid line) and 2004 (dotted line).
Vår 2003
Vår 2004
Hyt 2003
Adv 2004
1000
total goose number
800
600
400
200
0
4
10
16
May
22
28
3
9
June
Figure 5. Arrival dates of satellite-tagged Pink-footed Geese staging in southwest and central Svalbard during spring
2003 and 2004. Total daily maximum numbers counted at Vårsolbukta (Vår), Hyttevika (Hyt) and Adventdalen (Adv)
are shown in the histogram columns. Inserted are Svalbard arrival dates (triangles) for individual satellite-tagged geese.
686
ARDEA 94(3), 2006
MAY
Spitsbergen
N
Barentsøya
AdvSassendalen
Isfjord
Edgeøya
Vårsolbukta
last
22.5
Condition of males from Vesterålen to breeding
At departure from Vesterålen, the average API of
adult male geese scored in the field was in both
years 3.3, which did not differ significantly from
the male geese attached with satellite transmitters
(Fig. 7). Following the migration across the
Norwegian Sea of c. 1100 km, lasting for an average of 2.2 days, the geese were down to an average API of 0.9 (2003) and 1.4 (2004) on arrival to
pre-breeding areas in Adventdalen and 1.5 at
Vårsolbukta in 2004 (Fig. 7). On the breeding
grounds in Sassendalen, central Spitsbergen, 5–11
days after arrival in Adventdalen the average API
was 1.0 (2003) and 1.6 (2004).
DISCUSSION
Hyttevika
last
26.5
50km
Figure 6. Movements and staging areas of transmitter
tagged Pink-footed Geese in Svalbard during May 2003
and 2004. Movements in 2003 (black lines, solid symbols) and 2004 (grey lines, open symbols). Dates are
those of the last up-link received from each transmitter.
was 5.2 days (± 3.1, n = 11). On average, tagged
geese used 1.9 staging areas prior to 1 June with
an average pre-nesting staging period for each
satellite tagged goose of 9.1 days (± 2.0, n = 5,
year 2003) and 7.1 days (± 2.9, n = 6, year
2004), respectively (Fig. 2). Dispersion ranges
(50%) of staging geese are given in Table 1.
Dispersion ranges did not differ between the two
years.
Following pre-nesting staging, transmitter
tagged geese dispersed in three different ways.
Three geese remained at their first staging area
after 1 June (A4T, A5E, C1T), while another three
had arrived on western and northern coastal areas
around 1 June (A4H, B6K, B6V). The last three
geese moved to other central Spitsbergen areas
around 1 June (A2F, A4Z, B1Z).
Effects of transmitters on tagged birds
Of concern with any deployment of remote devices
attached to free-flying birds are their effects on
behaviour and energy balance. The fitting of harnesses and radio devices will inevitably restrict
movement, contribute drag in flight and add to the
body mass carried throughout the annual cycle.
Clearly if such effects are sufficient to make the
behaviour of the geese atypical, this severely
restricts our ability to use data from tracked individuals to make general inferences about the population as a whole. Yet, different observations indicate no adverse performance of those Pink-footed
Geese we have fitted with satellite transmitters.
The migration routes taken by the satellite-tagged
geese are not different to those without such
devices, and the arrival and departure dates to and
from staging areas correspond very well with those
of the population as a whole. Also, the mean
length of stay was similar to those estimated from
resightings of collared individuals. The abdominal
profiles of staging birds in Vesterålen did not differ
between satellite tagged and collared individuals.
Moreover, 10 out of 14 adult satellite tagged males
were mated during their stay in Denmark (2),
Trondheim Fjord (3) or Vesterålen (5). Furthermore, 11 of the geese have been identified on the
wintering grounds, with the latest neckband
Glahder et al.: PRE-NESTING SITE USE OF PINK-FOOTED GEESE
API
departure, Vestertål
4
arrival, Svalbard
129 149
6
pre. nest
Svalbard
2003
2004
5
3
2
18
2
202
3
17
66
1
0
Vestål*
Vestål
Vårsol
Advent
Sassen
Figure 7. Changes in mean Abdominal Profile Index Scores
of male Pink-footed Geese in Vesterålen and Svalbard
during May 2003 and 2004. APIs at the time of departure
from Vesterålen are shown both for geese attached with a
satellite transmitter (Vestål*) and geese without transmitters (Vestål) during the same period. In Svalbard APIs of
geese without transmitters were scored at Vårsol:
Vårsolbukta, SW Spitsbergen, Advent: Adventdalen,
Central Spitsbergen, Sassen: Sassendalen, Central
Spitsbergen. Given are means + SD with sample size.
resightings on their first (2), second (7) and third
(2) winter after they were caught and ringed. Two
of the 14 geese were lost during their first autumn
migration through Sweden and Denmark (shot).
Finally, two geese were observed with at least one
juvenile on their first and third winter, respectively.
In a similar study of Greenland White-fronted
Geese Anser albifrons flavirostris there was no significant difference in annual survival of geese
deployed with transmitters and those just carrying
neck-collars (Fox et al. 2003). Hence, based on
these performance indicators, there appears no
basis for concluding that the deployment of satellite transmitter had a serious effect on the individuals concerned. However, we cannot fully reject
the possibility that these birds behaved atypically
because of the attached transmitters.
The migration routes
If we make the assumption that birds were not
adversely affected by the deployment of transmit-
687
ters, these results provide a fascinating and previously unavailable insight into the individual spring
migration schedules of Pink-footed Geese. They
demonstrate, for instance, that in travelling from
Trondheim Fjord to Vesterålen, the geese do not use
any other, hitherto unknown, staging areas in
Norway during their migration northwards. Furthermore, on the migration leg from Vesterålen to
Svalbard, just one of the tagged birds put down on
Bjørnøya for a few hours. These factors are an important corroboration of our current knowledge, confirming present incomplete observations and gives
greater confidence in modelling the energetic consequences of migration and foraging strategies adopted
by different individuals (see Bauer et al. 2006).
Timing of departure from Vesterålen
Long-distances migrants typically show dramatic
but pre-programmed changes to their body stores
(such as fat deposits) that enable them to overcome ecological barriers (such as mountain ranges
and open sea) by sustained periods of flight (e.g.
Alerstam & Lindström 1990, Berthold 1993). The
Svalbard Pink-footed Goose migrates about 3000
km from its wintering quarters to Svalbard with
Vesterålen as the final staging area. Prior to arrival
in Vesterålen the satellite fitted geese staged in the
Trondheim Fjord area for on average 13 and 22
days in the two years. The staging period in
Vesterålen was relatively short (4–6 days duration
on average based on the satellite tagged birds in
the two years of our study, about 4 days based on
observations of neck-collared birds compared to
2–3 weeks in Trondheim Fjord and amongst
Greenland White-fronted Geese in Iceland, Fox et
al. 2003). Modelling shows, however, that the
stopover in Vesterålen is of great importance during spring migration and that the condition at
departure of geese leaving for unknown conditions
on Svalbard has potential fitness consequences for
the individual (Bauer et al. submitted). Failure to
attain threshold body stores to undertake the flight
and invest in a reproductive attempt after arrival
could result in death or at least failure to reproduce in that season (Madsen & Klaassen, unpubl.).
The departure time from these staging areas is
688
ARDEA 94(3), 2006
likely to be influenced by the internal state of the
individual, especially with regard to accumulation
of adequate energy and nutrient stores. This in
turn may reflect the individual’s condition on
arrival in Vesterålen and the feeding conditions
and costs encountered by that individual associated with staging there (Klaassen et al. 2006). The
departure date may also be further adjusted in
relation to weather conditions, the energetic costs
of flight being potentially minimised if there is a
high probability of encountering tailwinds to assist
passage, weighted against the fitness costs of the
delay (e.g. Clausen et al. 2003, Fox et al. 2003).
These factors combined undoubtedly explain the
short truncated departure defined by the staging
phenology curve compared to the arrival phase
(see Fig. 3). Intensive scaring from farmers can
also play a role in body condition and staging
behaviours of the geese in Vesterålen. Disturbance
from spring hunt of Greater Snow Goose Anser
caerulescens atlanticus reduced body condition
partly due to energy lost while moving to alternative feeding habitats (Béchet et al. 2004). Despite
less scaring in 2004 compared to intensive scaring
in 2003 no improvement of body condition in
2004 was seen, but geese were more site faithful
in 2004 (Tombre et al. 2005a). These findings are
in agreement with those of the transmitter tagged
geese (Fig. 7).
Capital or income breeding in
Pink-footed Goose?
Much of the ‘Travelling to Breed’ workshop dealt
with the relative contribution of endogenous
energy and nutrients to the eggs laid by long-distance migratory birds. Stable isotope markers in
the food, body and eggs of migratory geese suggest that laying females adopt a mixed capital/
income breeding strategy, i.e. investing both
endogenous stores and nutrients derived from the
breeding areas in egg production (Gauthier et al.
2003, Schmutz et al. 2006). Examples from several
goose studies seem indirectly to support the
importance of the additional income strategy by
feeding intensively at the breeding grounds
(Choinière & Gauthier 1995; Ganter & Cooke
1996). In the case of the Svalbard-breeding Pinkfooted Goose, the satellite tagged birds showed an
average staging period within Svalbard of eight
days, and studies in the two years concerned
showed first egg dates to fall between 26 and 31
May. This date seems to have changed little since
the time of Løvenskiold (1963) who reported the
first eggs laid in the first days of June. Rapid ovarian follicular growth takes 11–14 days in arcticnesting geese (Raveling 1978); hence to attain
first egg dates in late May, rapid oocyte development must therefore start in Vesterålen on the
penultimate staging areas. This is confirmed by
females shot upon arrival in SW Svalbard around
20–26 May 2003 having well developed follicles.
So at least some ‘capital’ is invested in egg formation on migration, even if this is supplemented by
income derived at Svalbard staging and ultimate
breeding quarters. This may also contribute to the
explanation as to why scaring on Vesterålen has
fitness consequences for the population (Madsen
1994, Bauer et al. 2006, Klaassen et al. 2006). The
argumentation above is valid for the two study
years and different environmental conditions can
influence the chosen strategy. Yet, this flexibility
can be restricted due to a possible heritability of
migration duration and arrival time as indicated in
snow geese (Bêty et al. 2004).
Significance of staging in Svalbard
When geese depart from Vesterålen they probably
have no cues of the feeding conditions in Svalbard
(Fox et al. 2006). Shortly after a 1100 km energetically expensive flight, females lay a clutch of 4–5
eggs, which they incubate for 24–26 days (Owen
1980), necessitating considerable investment of
protein and energy. Numerous studies have
demonstrated a reproductive advantage amongst
northern nesting geese arriving early on breeding
areas in best condition (Cooke et al. 1995, Kokko
1999, Bêty et al. 2004). Since rapid oocyte development for some birds will have already started
before departure from Vesterålen staging areas,
females have minimised the period before first
egg-laying, given favourable breeding conditions.
Studies in Svalbard showed that despite appar-
Glahder et al.: PRE-NESTING SITE USE OF PINK-FOOTED GEESE
ently poor feeding conditions, male API scores
increased at a low rate at Vårsolbukta and Adventdalen, amongst males that spend most of their
time alert during the arrival and pre-breeding
phases in Svalbard (Fox et al. 2006, ADF and CEH
unpubl.). Hence, pre-nesting feeding in Svalbard
by females which devote most of their time to
feeding, can contribute substantially to their nutrient stores and thus their reproductive success.
This study has been important in identifying
pre-breeding feeding areas as critical habitat for
Pink-footed Geese. Although this study involved
very small numbers of marked individuals, the
general patterns seems to be that southwestern
Svalbard and the Isfjord area in central Spitsbergen represent significant spring staging areas
for Pink-footed Geese with staging periods of 7–9
days. A branch of the North Atlantic current
reaches the west coast of Spitsbergen and the mild
influence of this water may affect the snow cover
along the southwestern coast, which makes this
area of such importance to staging birds (e.g.
MODIS image, 25 May 2002, http://visibleearth.
nasa.gov/cgi-bin/viewrecord?17834). If this and
the inner Isfjord system offer predictably snow free
or early thawing foraging opportunities, Pinkfooted Geese arriving to these areas would benefit
from accumulating body stores prior to reproduction. This would enable them to contribute stores
to oocyte development prior to arrival on breeding
areas further north and east, where conditions
upon arrival were likely harsher.
From the knowledge derived in this study from
Svalbard pre-nesting areas discovered by satellite
telemetry, it is possible to identify potential prenesting staging areas on the entire Svalbard using
parameters like geographical region, altitude, temperature gradients affecting early thaw and vegetation indices (NDVI: Normalised difference vegetation index) (Glahder 1999a). The most important
of these areas regarding goose use can then be identified by e.g. aerial survey (Glahder et al. 2002) and
subsequently, key areas can be conserved.
689
ACKNOWLEDGEMENTS
We would like to thank all the people, who have provided
observations of neck-collared geese for the database on
ringed Pink-footed Geese, Peter Mikkelsen, NERI, for
extracting data from the Pink-foot database and Peter
Aastrup, NERI for his help with transforming the satellite
data into the GIS platform for analysis, and two anonymous referees who’s comments improved the manuscript.
The study was performed under the EU 5th framework
project FRAGILE (EVK2–2001–00235).
REFERENCES
Alerstam T. & Lindström A. 1990. Optimal bird migration: The relative importance of time, energy and
safety. In: Gwinner E. (ed) Bird migration: physiology
and ecophysiology: 331–351. Springer Verlag, Berlin.
Argos CLS. 1996. User’s manual 1.0. Argos CLS, 31526
Ramonville Cedex, France.
Bauer S., Madsen J. & Klaassen M. 2006. Intake rates,
stochasticity, or onset of spring – what aspects of
food availability affect spring migration patterns in
Pink-footed Geese Anser brachyrhynchus? Ardea 94:
555–566.
Béchet A., Giroux J.-F. & Gauthier G. 2004. The effects of
disturbance on behaviour, habitat use and energy of
spring staging snow geese. J. Appl. Ecol. 41: 689–700.
Bêty J., Giroux J.-F. & Gauthier G. 2004. Individual variation in timing of migration: causes and reproductive
consequences in greater snow geese (Anser caerulescens atlanticus). Behav. Ecol. Sociobiol. 57:1–8.
Berthold P. 1993. Bird migration. A general survey.
Oxford University Press, Oxford.
Clausen P., Green M. & Alerstam T. 2003. Energy limitations
for spring migration and breeding: the case of brent
geese Branta bernicla tracked by satellite telemetry to
Svalbard and Greenland. Oikos 103: 426–445.
Cooke F., Rockwell R.F. & Lank D.B. 1995. The snow
geese of La Perouse Bay – Natural selection in the
wild. Oxford University Press, Oxford.
Dixon K.R. & Chapman J.A. 1980. Harmonic mean measure of animal activity areas. Ecology 61: 1040–1044.
Fox A.D., Francis I.S. & Bergersen E. 2006. Diet and habitat use of Svalbard Pink-footed Geese Anser brachyrhynchus during arrival and pre-breeding periods in
Adventdalen. Ardea 94: 691–699.
Fox A.D., Glahder C.M. & Walsh A.J. 2003. Spring migration
routes and timing of Greenland white-fronted geese results from satellite telemetry. Oikos 103: 415–425.
Gauthier G., Bêty J. & Hobson K.A. 2003. Are greater
snow geese capital breeders? New evidence from a
stable-isotope model. Ecology 84: 3250–3264
690
ARDEA 94(3), 2006
Glahder C.M. 1999a. Spring Staging Areas of the
Greenland White-fronted Goose (Anser albifrons flavirostris) in West Greenland. Arctic 52: 244–256.
Glahder C.M. 1999b. Sensitive areas and periods of the
Greenland White-fronted Goose in West Greenland.
Spring staging and moult as important bottleneck
periods in the annual cycle of the goose subspecies.
PhD thesis. National Environmental Research
Institute. Department of Arctic Environment.
Glahder C., Fox A.D. & Walsh A.J. 1997. Effects of fitting
dummy satellite transmitters to geese. Wildfowl 48:
88–97.
Glahder C.M., Fox A.D. & Walsh A.J. 1999. Satellite
Tracking of Greenland White-fronted Geese. Dansk
Orn. Foren. Tidsskr. 93: 271–276.
Glahder C.M., Fox A.D. & Walsh A.J. 2002. Spring staging
areas White-fronted Geese in West Greenland; results
from aerial survey and satellite telemetry. Wildfowl
53: 35–52.
Hübner C.E. 2006. The importance of pre-breeding sites
in the arctic Barnacle Goose Branta leucopsis. Ardea
94: 701–713.
Klaassen M., Bauer S., Madsen J. & Tombre I. 2006.
Modelling behavioural and fitness consequences of
disturbance for geese along their spring flyway. J.
Appl. Ecol. 43: 92–100.
Kokko H. 1999. Competition for early arrival in migratory birds. J. Anim. Ecol. 68: 940–950.
Løvenskiold H.L. 1963. Avifauna Svalbardensis. Norsk
Polarinstitutt Skrifter 129: 1–460.
Madsen J. 1994. Impacts of disturbance on migratory
waterbirds. Ibis 137: S67–S74.
Madsen J., Kuijken E., Meire P., Cottaar F., Haitjema T.,
Nicolaisen P.I., Bones T. & Mehlum F. 1999. 4. Pinkfooted Goose Anser brachyrhynchus: Svalbard. In:
Madsen J., Cracknell G. & Fox A.D. (eds) Goose
Populations of the Western Palearctic. A review of
status and distribution: 82–93. Wetlands International Publ. 48, Wetlands International, Wageningen, The Netherlands. National Environmental
Research Institute, Rønde, Denmark.
Madsen J. & Klaassen M. 2006. Assessing body condition
and energy budget components by scoring abdominal
profiles in free-ranging Pink-footed geese Anser
brachyrhynchus. J. Avian Biol. 37: 283–287.
Mainguy J., Bêty J., Gauthier G. & Giroux J.-F. 2002. Are
body condition and reproductive effort of laying
Greater Snow Geese affected by the spring hunt?
Condor 104: 156–161.
Owen M. 1980. Wild geese of the world. Batsford,
London.
Raveling D.G. 1978. The timing of egg laying in northern
nesting geese. Auk 95: 294–303.
Schmutz J.A., Hobson K.A. & Morse J.A. 2006. An isotopic assessment of protein from diet and endogenous stores: effects on egg production and incubation
behaviour of geese. Ardea 94: 385–397.
Tombre I.M., Madsen J., Bakken J., Bergland O.-P.,
Kristensen J.B. & Røsshag B. 2005a. Kortnebbgjess og
hvitkinngjess i Vesterålen. Bruk av områder og individuell adferd. NINA Rapport 3.
Tombre I.M., Madsen J., Tømmervik H., Huagen K.-P. &
Eythórsson E. 2005b. Influence of organised scaring on
distribution and habitat choice of geese on pastures in
Northern Norway. Agric., Ecosyst. Environ. 11: 311–320.
Ward D.H. & Flint P.L. 1995. Effects of harness-attached
transmitters on pre-migration and reproduction of
Brant. J. Wildl. Manage. 59: 39–46.
SAMENVATTING
In dit onderzoek zijn de trekroutes van de Kleine Rietgans
Anser brachyrhynchus van Denemarken naar Spitsbergen
nader onderzocht. De aandacht richtte zich vooral op plekken op Spitsbergen die de ganzen aandoen voor ze gaan
broeden – een belangrijke periode in de jaarcyclus waarvan bij de onderzochte soort tot nu toe weinig bekend is.
Om de ganzen te volgen werden in maart 2003 en 2004
14 adulte ganzen in Denemarken (Vest Stadil Fjord)
gevangen en voorzien van satellietzenders die op batterijen (11) of zonne-energie (3) werkten. Vanuit
Denemarken vlogen de gezenderde ganzen eerst richting
Midden-Noorwegen, naar de streek rond de Trondheim
Fjord. Na 2–3 weken trokken ze door naar Vesterålen in
Noord-Noorwegen (aankomst- en vertrekdata 10 en 17
mei 2003 en 15 en 19 mei 2004). Gemiddeld bleven de
gezenderde ganzen hier 4–6 dagen. Vanaf Vesterålen trokken de ganzen linea recta naar Spitsbergen, waar ze
gemiddeld op 22 mei 2003 en 21 mei 2004 aankwamen.
De ganzen pleisterden hier in kustgebieden in het zuidwesten van Spitsbergen (5 vogels) en rond de Isfjord in
Centraal-Spitsbergen (6), gebieden die worden gekenmerkt door een vroege inval van de dooi. Tot 1 juni verbleven de ganzen gemiddeld op twee pleisterplaatsen. In
beide jaren werden de eerste eieren in Sassendalen,
Centraal-Spitsbergen, tussen 26 en 31 mei gelegd. De kans
is dus groot dat de gezenderde vogels vóór 1 juni op hun
broedplek waren aangekomen. De betrekkelijk korte tijd
tussen aankomst op Spitsbergen en eileg maakt het aannemelijk dat de eieren al in Vesterålen tot ontwikkeling
beginnen te komen. Deze veronderstelling werd ondersteund door waarnemingen van zich ontwikkelende eieren
bij ganzen die bij aankomst op Spitsbergen zijn geschoten.
Received 27 January 2005; accepted 15 April 2006
ARDEA is the scientific journal of the
Netherlands Ornithologists’ Union (NOU),
published bi-annually in spring and autumn.
Next to the regular issues, special issues are
produced frequently. The NOU was founded in
1901 as a non-profit ornithological society,
composed of persons interested in field
ornithology, ecology and biology of birds. All
members of the NOU receive ARDEA and
LIMOSA and are invited to attend scientific
meetings held two or three times per year.
Subscription ARDEA – Separate subscription to Ardea is possible. The 2007
subscription rates are € 33 (The Netherlands), € 37 (Europe), and € 43 (rest of
the world). See website for institutional subscription rates. Payments to
Postbank account 125347, as indicated below under Membership NOU.
Correspondence concerning subscription, and orders for back volumes to:
J.J. de Vries, Oosterend 10 b, 8897 HZ Oosterend, The Netherlands
([email protected]).
Internet – www.ARDEAjournal.nl
NETHERLANDS ORNITHOLOGISTS’ UNION (NOU)
Membership NOU – The 2007 membership fee is € 41 (or € 24 for persons <25
years old at the end of the year). Foreign membership amounts to € 53 (Europe),
or € 63 (rest of the world). All payments to Postbank account 125347 in the
name of Nederlandse Ornithologische Unie, Ir. van Stuivenbergweg 4, 6644 AB
Ewijk, The Netherlands (BIC: PSTBNL21 IBAN: NL65 PSTB 0000 125347).
Correspondence concerning membership: J.J. de Vries, Oosterend 10 b, 8897
HZ Oosterend, The Netherlands ([email protected]).
Internet – www.nou.nu