Spring staging by Barnacle geese Branta leucopsis,
and the effects of a management plan in the Herøy
district in Nordland, Norway.
Paul Shimmings
Barnacle goose Brian Morrell
CONTENTS
SAMMENDRAG...........................................................................................................2
1. INTRODUCTION .....................................................................................................7
1.1 Svalbard Barnacle Goose population...................................................................7
1.2 Spring migration and staging ...............................................................................8
1.3 Conflicts between Barnacle geese and agriculture in Norway and management
plans affecting the Svalbard population...................................................................11
2. METHODS ..............................................................................................................15
2.1 Material and methods used to evaluate the effect of management on Barnacle
geese.........................................................................................................................15
3. RESULTS ................................................................................................................16
3.1 Timing (phenology) of migration and counts of Barnacle geese in the Tenna,
Sør-and Nord-Herøy area.........................................................................................16
3.2 Arrivals of new ringed individual Barnacle geese in the Tenna, Sør- & NordHerøy area................................................................................................................19
3.3 Goose scaring methods used in the Tenna, Sør- & Nord-Herøy area and their
effects on geese. .......................................................................................................26
3.4 The effects of the Barnacle goose management plan on goose distribution in the
Tenna, Sør- & Nord-Herøy area. .............................................................................33
3.5 The effects of fertilising of alternative feeding sites on Tenna and Sør-Herøy. 38
3.6 The effects of burning of vegetation on goose distribution. ..............................41
3.7 Movements of individually ringed geese away from Tenna, Sør- & Nord-Herøy.
..................................................................................................................................42
3.8 The effects of the management plan in Herøy on Barnacle geese – length of
stay, body condition and reproductive success. .......................................................47
4. DISCUSSION ..........................................................................................................56
5. RECOMMENDATIONS.........................................................................................57
6. ACKNOWLEDGEMENTS.....................................................................................61
7. REFERENCES ........................................................................................................62
1
SAMMENDRAG
Bestandsutvikling:
Siden nær utryddelse på slutten av 1940-tallet har det vært en dramatisk økning i
antall individer i Svalbard-bestanden av hvitkinngås Branta leucopsis. I 1948 var
bestanden estimert til å være ca. 300 individer, men på slutten av 1990-tallet telte
bestanden mellom 22 – 24000 individer (Figur 1).
Rasteplasser på vårtrekk:
Flokker med hvitkinngås mellomlander flere steder både på Helgeland og i
Vesterålen på vårtrekk (Figur 2).
I perioden 1975 – 1982 rastet hvitkinngjess nesten utelukkende på øyer ytterst på
Helgelandskysten (Figur 3). I perioden 1983 – 1992 begynte antall rastende gjess å
øke på flere nye lokaliteter på Helgeland. I mange av disse nye områdene var det
intensivt landbruk (Figur 4). Siden 1994 har hvitkinngjess spredt seg til stadig nye
områder, helt nord til Vesterålen (Figur 5). De første rastende individene i Vesterålen
ble sett i 1975.
Mulige årsaker til at hvitkinngjess har flyttet til nye områder er negative forandringer
i habitat i de tradisjonelle rasteområdene, forandringer i forvaltning bl.a.
forvaltningsplaner for gjess, økning i bestandsstørrelse, og klimaendringer. Det kan
være fordeler ved å raste lenger nord, da siste etappe til hekkeplasser på Svalbard
blir kortere.
Forvaltningsplanen for hvitkinngjess:
Det finnes tre ulike handlings- og forvaltningsplaner som berører Svalbard-bestanden
av hvitkinngjess, nemlig en internasjonal ”flyway” plan, en nasjonal handlingsplan
for alle gåsearter i Norge, og en lokal forvaltningsplan for hvitkinngjess i Herøy
kommune i Nordland.
På øyene Tenna, Sør-Herøy og Nord-Herøy i Herøy kommune får gjessene beite i fred
i et friområde for gjess, mens de blir jaget fra et skremmeområde (Figur 6).
Friområdet består av marginal beitemark og strandengvegetasjon, mens
skremmeområdet består av fulldyrket eng.
Data om hvitkinngjessenes bruk av områder i Herøy kommune har blitt innsamlet i en
årrekke. For å kunne se på effekter av forvaltningen på gjessene, er det her presentert
en oppsummering av analyser av disse dataene, hovedsakelig fra perioden 1994 –
2002. Forvaltningsplanen ble satt i gang i 1996. Det foreligger data både før og etter
iverksetting av planen.
Tellinger av hvitkinngjess på Tenna, Sør-Herøy og Nord-Herøy:
Gjessene finnes fra midten av april til slutten av mai. De fleste drar imidlertid videre
litt etter 15. mai (Figurene 7 – 9). Første observasjon pleier å være i de siste 10 dager
av april, men ankomsttiden variere mye fra år til år (Figur 10). Første observasjoner
av ringmerkede individer i området hvert år ser ut til å gjenspeile reelle økninger i
antallet i områder (Figurene 11 – 13) og trekk fra overvintringsområder i
Storbritannia.
2
I 3 av de 4 sesongene før den lokale forvaltningsplanen ble satt i verk var antall gjess
i Herøy-området over 3000 individer på den høyeste tellingen (Figur 14). Dette er
summen av antll individer i områdene Tenna, Sør-Herøy og Nord-Herøy (Figur 15)
til sammen. På alle tre øyene har antallet gått tilbake etter 1996, særlig i de tre siste
sesonger (Figurene 16 – 24). Den meste dramatiske nedgang i antall rastende
hvitkinngjess er på Tenna, der antallet nå er ca. 50% av det som fantes i begynnelsen
og midten av 1990-tallet (Figurene 16 – 18) .
Skremming av hvitkinngjess i Herøy kommune:
Flere metoder har blitt tatt i bruk for å skremme hvitkinngjess vekk fra dyrket jord på
Tenna, Sør- og Nord-Herøy. Blant annet har jaging blitt benyttet mye. 16% av all
registrert jaging har funnet sted i friområdet (Tabell 2). Bruk av signalpenn har vist
seg å være en effektivt måte å skremme gjess, og alltid resultert i at gjessene tok til
vingene. Tomme skudd har også vært benyttet som skremselsmetode. Noen ganger var
det nødvendig å avfyre flere skudd før flokken flyttet seg til friområdet. Den mest
brukte metoden har vært å tre fargete plastbånd over jordene for å hindre gåsa i å
lande. Etter hvert har hvitkinngjess vendt seg til båndene. De lander i arealene nær
jordene og går ut på jordene under båndet. Allikevel ser båndetene ut til å ha en
virkning mot beiteskader forårsaket av hvitkinngjess, siden det er registrert høyere
tettheter av gåseekskrementer i områder uten bånd enn i områder med bånd (Figur
25). Tettheten av gåseekskrement var 5,05 per kvadratmeter i områder uten
skremmebånd, mot 0,75 per kvadratmeter i områder beskyttet med bånd (Figur 26). I
arealer hvor det ble brukt gasskanoner for å skremme gjess, øker tettheten av
ekskrementer med avstanden fra kanonen (Figurene 26 – 29). Det var vanskelig å si
noe konkret om virkningen av andre metoder som for eksempel bruk av fugleskremsler
og ballonger.
Konsekvenser av skremming:
Gjessenes arealbruk på Herøy har endret seg. De bruker nå i større grad friområdet
(Figur 30). Før forvaltningsplanen ble satt i verk var gjessene i det som nå er
friområde ca. 60% av tiden, mens de nå bruker friområdet ca. 85% av tiden. Før
forvaltningsplanen ble satt i verk, pleide hvitkinngjessene å samle seg i større flokker
på dyrka jord, særlig tidlig på dagen og seint på kvelden. Siden de ikke lenger får
være i fred på dyrka jord har de færre sjanser til å samle seg i større flokker, og
gjennomsnittlig flokkstørrelse har blitt mindre (Figur 31). Til tross for intensiv
skremming, oppsøker enkelte individer dyrka mark gjentatte ganger (Figur 32).
Som en konsekvens av skremming har gjessene vært nødt til å finne alternative
beiteområder. I 1996 ble de første flokkene med hvitkinngjess registrert på NordHerøy. Antallet økte i seinere sesonger, men har siden avtatt litt (Figur 33).
Avlesning av fotringer har gitt informasjon om hvor Nord-Herøy fugler har kommet
fra. Både individer som ellers har beitet på Tenna og på Sør-Herøy har blitt observert
på Nord-Herøy, med en hovedvekt av individer fra Sør-Herøy (Tabell 3). Antallet av
nyoppdagete individer på Nord-Herøy var størst i årene 1998 og 1999 (Tabell 4), som
var de første årene med intensiv ringavlesning på Nord-Herøy.
Områdeforvaltning:
To områder, Langvalen på Tenna og Svinøya på Sør-Herøy, har blitt gjødslet for å
øke beitekvaliteten (Figur 34). Både antall gåsedager (Figur 35) og det årlige høyeste
antall gjess registrert i disse to områdene (Figur 36) har gått ned i perioden 1994 –
3
2002. Utviklingen er den samme når antallet gjess i disse to områdene beregnes som
prosentandel av totalt antall gjess i hele Herøy-området (Figur 37). Begge steder må
derfor betegnes som mindre attraktive for hvitkinngjessene etter at de ble gjødslet enn
før. Mulige årsaker til dette kan være at feil type eller mengde gjødsel har vært brukt,
eller at andre steder i nærheten av en eller annen grunn er blitt mer attractive.
Et sted ved Dammen på Tenna har blitt brent for å gjøre beitekvaliteten bedre. Den
høyeste tellingen for denne lokaliteten var i 1998 (Tabell 5), det samme året som
vegetasjonen ble brent. Siden har årlig maksimumsantall gjess registrert der variert
mye fra år til år.
Endringer i antall hvitkinngjess i områder nord for Herøy:
Hvitkinngjessene har forandret adferden siden forvaltningsplanen ble satt i gang i
1996. Siden de i større grad beiter nå i mer marginale habitater og dyrka jord ikke er
tilgjengelig i særlig grad, kan bæreevnen i området ha gått ned. På samme tid har
antall gjess økt andre steder nord for Herøy. Flere ringmerkede gjess som i tidligere
sesonger har blitt sett på Herøy blir nå observert på rasteplasser i Vesterålen (Figur
38). De fleste av disse individene er eldre enn 3 år gamle (Figur 39). Kun 5 av 58
individer som har flyttet fra Herøy til Vesterålen er yngre enn 3 år (Figur 40).
Individer som tidligere har blitt sett på Herøy har også vært observert på rasteplasser
mellom Herøy og Vesterålen, bl.a. på Vandve i Dønna kommune og Selvær i Træna
kommune (Tabell 7). Man kan spekulere på i hvilken grad individene ”øyhoppet”
inntil de ”oppdaget” Vesterålen.
Det er en tendens til at gjess fra hekkekolonier nord på Svalbard bruker de nordligste
rasteplassene langs norskekysten. Prosentandelen av individer fra kolonier i nordlige
deler av Svalbard er høyere på Andøya, Sortland og Selvær, enn ved rasteplasser sør
for Selvær (Figur 41). Forvaltningsplaner for vårbeiteområdene kan derfor ha
påvirkning på gjessenes hekkesuksess på koloni-nivå på Svalbard.
Det foreligger tellinger fra en rekke områder som er brukt av hvitkinngjess på
vårtrekk i perioden 1993 – 2002 (Tabell 8). Av 22 områder der antall hvitkinngjess
har økt i de siste ti år, er 13 nord for Herøy kommune (Figur 42). Alle de 9 områdene
det har vært en nedgang i antall hvitkinngjess i de siste ti år er enten i eller sør for
Herøy.
Gjessenes opphold på Herøy:
Hvitkinngjessene oppholder seg lenger på Herøy siden forvaltningsplanen ble satt i
gang. I perioden 1994 – 1996 var intervallet fra gjennomsnittlige ankomst dato til
gjennomsnittlige reisedato hovedsakelig mellom 7 og 9 dager. Etter 1996 har dette
intervallet økt til mellom 11 og 14 dager. Gjennomsnittlig antall dager ringmerkede
individ var til stede på Herøy varierte fra år til år (Tabell 10). Noen individer er kun
sett på én dag i sesongen (Figur 43).
Kroppskondisjon og hekkesuksess hos hvitkinngjess på Herøy:
For å kunne måle kroppskondisjon hos hvitkinngjess er 100 tilfeldige bukprofiler
registrert (Figur 45) hver dag, i tillegg til profilene hos ringmerkede individer.
Sluttkondisjon, målt den 15. mai hvert år har blitt gradvis dårligere i perioden 1993 –
2002 (Figur 46). Den daglige økningen i kondisjon for et individ, målt som vekst i
4
bukprofil, varierer fra år til år (Figurene 47 & 48). Kondisjonen er imidlertid alltid
bedre når de dro Herøy enn når de ankommer. Kondisjonsøkningen per dag i 1994 –
2002 blir i suksessivt sesongene mindre, uavhengig om man ser på økningen per dag
fra tilfeldige registreringer av bukprofiler (Figur 49) eller hos ringmerkede individer
(Figurer 50 – 52). Mulige forklaringer på dette er bl.a. at gjessene er i dårligere
kondisjon på grunn av at jaging medfører bruk av kroppsreserver, eller at de i
friområdet ikke får tilgang til mat med tilstrekkelig kvalitet.
Både antall unger produsert og antall par med vellykket hekking hos gjessene som
raster på Herøy har gått ned i perioden 1996 – 2000 (Figur 53). Antall unger per par
med vellykket hekking var 0,8 i 1996, og kun 0,2 unger i 2000 (Figur 54). Dette er i
samsvar med nedgang i prosentandel juveniler i Svalbard-bestanden i samme
tidsrom.
Det var ingen tydelig sammenheng mellom vektøkning hos hunnfugler og
hekkesuksess i perioden 1996 – 2000 (Figur 55).
Skremmemetoder og effekter på hvitkinngjess:
Forskjellige skremmemetoder har forskjellige effekter på hvitkinngjess. Metoden som
er mest utbredt på Herøy, er bruk av skremmebånd. Dette er kanskje den billigste
metode for å holde gjess unna dyrka jord. Som med andre metoder, begynner
imidlertid gjessene å venne seg til båndene. For å kunne garantere at gjess ikke beiter
der de er uønsket er det best å jage flokkene vekk. Gasskanoner har liten effekt på
gjessene.
Antall hvitkinngjess på lokaliteter nord for Herøy har økt, på samme tid som jaging
og annen skremming ble intensivert på Herøy. Det er vanskelig å vite i hvilken grad
selve skremmingen har vært årsaken til økningen i antall hvitkinngjess på disse
stedene. Det faktum at en del ”Herøy-individer” gjess har flyttet seg både til steder
lenger nord på Helgelandskysten, og til lokaliteter i Vesterålen, tyder imidlertid på at
skremming kan ha forskjøvet problemet i stede for å løse det.
Diskusjon:
Vellykket forvaltning av beiteområder for hvitkinngjess er blitt komplisert. Særlig
siden individer har etablert seg i nye områder de siste årene. Forvaltningsplaner for
gjess må være fleksible nok til å kunne justeres med gjessenes endringer i arealbruk.
Erfaringer fra feltarbeid på Herøy kan brukes hvis andre kommuner skal sette i gang
forvaltningsplaner for (hvitkinn)gjess. Det er problemer assosiert med skremming, og
det finnes andre alternative tiltak som for eksempel kompensasjon for avlingstap eller
dyrking av områder spesielt for gjess. Siden individer fra kolonier lenger nord på
Svalbard er mer hyppige på rasteplasser lenger nord på norskekysten, så kan
forvaltningsplaner for hvitkinngjess påvirke fugler fra enkelte hekkeområder mer enn
andre.
Hvis skremsel fortsatt skal brukes som verktøy til å manipulere fordelingsmønster hos
hvitkinngjessene på Herøy bør skremselen effektiviseres. Det er viktig at gjessene
alltid har alternative beiteområder (dvs. friområder). Passive skremselsmetoder bør
flyttes med jevne mellomrom, og før gjessene blir vant til dem. Det er også viktig at
jagingen fortsetter selv i dårlig vær! Skremmebånd bør aldri brukes i nærheten av
gjessenes overnatingsplasser. Gjessene opplever disse plassene som trygge, og blir
5
vant til båndene der. Avstanden mellom rader med bånd må være slik at det blir
vanskelig for gjessene å lande på jordet.
Andre metoder som ikke har blitt utprøvd i perioden 1996 – 2002 inkluderer bruk av
hunder til å jage beitende gåseflokker, elektriske gjerder, og roterende lys.
6
1. INTRODUCTION
1.1 Svalbard Barnacle Goose population
There are three main breeding populations of Barnacle geese in the world. One of
these populations stages on the Norwegian coast during the spring migration between
the wintering areas on the Solway Firth (on the border between SW Scotland and NW
England) and the breeding colonies in Svalbard. This is hereafter referred to as the
Svalbard population.
The Svalbard Barnacle goose population has increased dramatically following near
extinction, from around 300 individuals in 1948, to the current population fluctuating
around 22 – 24000 individuals in the late 1990’s (Fig. 1). The recovery from nearextinction and the continued growth in numbers has been made possible by several
measures, including protection in both Britain, Norway and Svalbard, as well as the
provision of managed feeding sites and breeding sanctuaries.
30000
Figure 1. The growth of
the Svalbard population
of Barnacle geese based
upon counts in the
wintering area 1957 –
2000. Counts supplied by
The Wildfowl & Wetlands
Trust.
20000
15000
10000
5000
year
7
94
97
88
91
82
85
76
79
70
73
64
67
0
58
61
population
25000
1.2 Spring migration and staging
Each spring Barnacle geese leave the wintering grounds on the Solway Firth on their
way to the breeding grounds in Svalbard. Flocks of geese stage on various islands
along the west coast of Norway, at the present time in both Helgeland and in
Vesterålen (Fig. 2).
Svalbard
Vesterålen
Helgeland
Figure 2. Spring migration route of Svalbard Barnacle geese. Square = main wintering
area (Solway Firth). Triangles = main staging areas (Helgeland and Vesterålen).
The spring staging sites used by migrating Barnacle geese have been well documented
since intensive observations began in the mid-1970s. The distribution pattern for
spring staging geese during three periods of time are shown in Figures 3 - 5. The
traditional range in the period 1975 – 1982 (Gullestad et al. 1984) was at a time when
most Barnacle geese fed in traditionally managed habitats (hay meadows and areas of
low intensity grazing by sheep and / or cattle) (Fig. 3), mainly on small island groups
in the Helgeland area. Gradually, due to changes in management practices birds
moved to more intensively managed habitats within Helgeland and in the period 1983
– 1992 were staging much further north than the traditional range (Prop et al. 1998)
including at sites with more intensive agriculture (Fig. 4). After 1994 there was a
further expansion northwards (Follestad & Shimmings 2001, Shimmings 2002),
including to sites away from Helgeland (Fig. 5).
8
The southernmost staging sites are in the Vega district (65°40’N). The southernmost
limit has remained relatively unchanged since the mid 1970’s, whereas the population
has occupied staging sites much further north than the former range in Helgeland.
Svalbard Barnacle geese are now staging as far north as Vesterålen (69°30’N).
Possible reasons for this expansion in the spring staging range include habitat
degradation in traditional staging areas (Black et al. 1991), changes in local
management practices including implementation of local management plans
(Fylkesmannen i Nordland 1996), an increase in the total Svalbard population (Black
et al. 1999, WWT unpublished data), as well as climatic changes (Prop et al. 1998).
Birds staging further north may profit energetically on a much shorter final stage to
the migration route to the breeding grounds on Svalbard (Follestad & Shimmings
2001).
Male Barnacle goose Steve Edwards
9
1-500
501-1000
1001+
Figure 3. Spring staging areas for Svalbard
Barnacle geese 1975 – 1982 (from Gullestad
et al. 1984).
Figure 4. Expansion in the traditional
spring staging range for Svalbard Barnacle
geese 1983 – 1992 (from Prop et al. 1998).
10
Figure 5. Spring staging areas for Svalbard
Barnacle geese 1994 – 2001. Symbols show the
highest count recorded in the period 1994 – 2001
(from Shimmings 2002).
1.3 Conflicts between Barnacle geese and agriculture in Norway and management
plans affecting the Svalbard population
In Norway damage caused by geese most often occurs along the coast or in restricted
areas elsewhere (Follestad & Bø 1991). Barnacle geese on spring migration can cause
damage to agricultural grasslands, when they feed on small plants (Follestad & Bø
1991). Damage is restricted to the months of April and May. The Svalbard population
of Barnacle geese is protected throughout the range, and all sites used by this species
are governed by two nations (Norway and United Kingdom).
In most cases where complaints are made regarding grazing of pastures by grazing
geese the problems are related to potential loss of yield. In addition complaints are
often received from farmers in parts of Helgeland that release of sheep with lambs
onto grassland needs to be delayed by a few weeks as there is less grass available,
because the geese have grazed there first. Anecdotal evidence suggests that sheep
avoid grazing in areas where goose droppings are present, a finding confirmed by
studies by Rochard & Kear (1968).
In recent years considerable focus has been made on the conflicts between increasing
goose populations and solutions to alleviate agricultural damage. In 1996 a
mangement plan was implemented for the Herøy municipality in Nordland county
(Fylkesmannen i Nordland 1996). In 1996 a national action plan for geese in Norway
was prepared (Direktoratet for naturforvaltning 1996). An English summary of this
action plan was provided by Bø et al. (1998). In addition, a flyway management plan
for the Svalbard population of Barnacle geese was prepared (Black 1998a,
summarised in Black 1998b). Thus management of the population is addressed on
both local, national as well as at international levels.
Information boxes 1-3 attempt to summarise some of the main points from these three
plans (local, national and flyway), at least those points which are relevant with
regards the current situation in Norway during the spring migration.
Information box 1:
Local management plan for Barnacle geese on Tenna & Herøy (after
Fylkesmannen i Nordland 1996):
•
•
•
•
Establishment of undisturbed refuge zones.
Establishment of new grazing areas for sheep and cattle, away from core
problem areas.
Cultivation of new areas, both within and outside the refuge zone.
Goose scaring (both passive and active methods)
11
Information box 2:
National action plan (after DN 1996, Bø et al. 1998):
•
•
•
•
The staging areas shall be maintained through extensive co-operation with
land ownership / tenants.
Foraging areas of traditional importance outside damaged areas shall be
conserved or cultivated to maintain sufficient quality.
Alternative feeding areas for the geese in the areas exposed to damage is to
be bought, cultivated and managed or established by special agreements
with affected farmers.
Cultivation of formerly used areas will be considered by regional
authorities to ensure that environmental qualities are maintained and that
consideration for feeding geese is balanced against other interests of
environmental protection.
Information box 3:
Relevant points in the flyway management plan (after Black 1998 a,b):
•
•
•
•
•
•
•
•
To maintain and implement necessary protection of breeding, moulting
and staging Barnacle geese in Norway.
Maintain existing protection legislation for this species in Helgeland.
To maintain and implement protection of a network of key habitats for prebreeding, breeding, moulting and post-breeding in Svalbard, autumn
staging on Bjørnøya, and spring staging geese in Helgeland. If necessary
expand current areas of protection to include additional key sites.
Complete the process to establish site protection for key foraging and
roosting sites in Helgeland.
Compile and implement local habitat management plans for key sites in
Helgeland.
Maintain, refine and, if necessary, extend existing goose management
schemes near farmland: i.e. coastal grazing scheme.
Liase closely with farmers in areas of potential conflict to advise on
management options through local management plans.
Maintain, refine and, if necessary, extend habitat enhancement schemes on
traditional feeding areas.
12
All the points listed as important for the local plan for Herøy have been achieved to a
lesser or greater degree. As for the national action plan, only the two first points seem
to have been achieved. However, instead of buying land to be cultivated for goose
grazing, local authorities have come to an agreement with some landowners. As
regards the flyway plan, this has not yet been ratified by both the relevant countries
(Norway and the United Kingdom).
Management plans have been implented in only a few areas in Norway where geese
come into conflict with agricultural interests. The first working management plan for
Barnacle geese came into effect in 1996 in the Herøy region of Nordland county
(Fylkesmannen i Nordland 1996). The Herøy area had experienced an increase in
numbers of staging Barnacle geese since they were first recorded there in 1975. The
reasons for this increase in usage of sites in Herøy can be summarised as follows:
•
a degradation in quality of traditional grazing habitats (Black et al. 1991,
Hatten et al. 1995). Due to depopulation and cessation of management of
traditional habitats important for staging Barnacle geese such as on Lånan,
geese have been forced to find alternative sites (Black et al. 1991).
Traditionally meadow areas on Lånan were either grazed or cut for hay. Now
the areas are becoming overgrown (Hatten et al. 1995).
•
an increase in the total Svalbard population of Barnacle geese has led to a
move into new areas as traditional sites become filled to capacity (Shimmings
2001b).
As part of the management plan in the Tenna, Sør-Herøy and Nord-Herøy area
Barnacle geese are allowed to graze in undisturbed areas (mainly sheep pastures and
coastal grasslands, as well as small islets) whereas they are chased from the scaring
zone (intensively managed grasslands). The boundaries have been adjusted slightly
from time to time to accomodate small adjustments to satisfy various landowners, but
have nevertheless changed little since the original plan (Fig. 6). The only major
change since the original plan is that the fields at Høgtun farm on Sør-Herøy are not
within the refuge zone, but have been included in the scaring zone since 1997.
Various methods are employed to discourage geese from feeding withing the scaring
zone. The techniques are detailed in section 3.3 in this report. Parts of the refuge zone
have been fertilised, either before the arrival of the geese in order to provide swards
for the birds, or alternatively after the geese have migrated northwards to compensate
for “lost” sheep grazing. Lambing is also delayed by up to 3 weeks to alleviate the
problems associated with lack of grass early in the spring growing season. Alternative
new grazing areas for livestock have also been provided through ploughing and
reseeding.
13
Figure 6. Refuge (friområder) and scaring zones (skremmeområder) for Barnacle geese
on Tenna and Sør-Herøy (from Fylkesmannen i Nordland 1996).
14
2. METHODS
2.1 Material and methods used to evaluate the effect of management on Barnacle
geese
Data presented in this report were collected in the period 1994 – 2002, during the
peak staging period for Barnacle geese migrating between the Solway Firth (UK) and
Svalbard. Some data from the years 1992 and 1993 was also used. Therefore data is
presented from both before the Herøy management plan was implemented, and
subsequently. During each season data has been collected on the following:
•
•
•
•
•
•
•
counts of geese in the areas affected by the management plan; as well as at
sites not included in the plan;
reading of individually coded leg rings;
assessment of body condition for Barnacle geese (abdominal profiles – see
Owen 1981);
measurements of grazing intensity (dropping counts);
observations on disturbance to grazing goose flocks and its effect;
mapping of areas used by grazing Barnacle geese;
mapping of scaring devices.
Visits have also been made to other sites in the Herøy region to record Barnacle geese
(traditional sites with little or no conflict with agricultural interests). In addition data
has been provided by observers from other sites used by staging Barnacle geese,
including both areas with a long history of use by staging Barnacle geese, as well as
sites where geese have begun to stage more recently.
It is these data that have been used in this report in an attempt to evaluate the
consequences of the management plan for Barnacle geese in the Herøy area, as well
as to look at changes in distribution and numbers in areas other than Herøy.
15
3. RESULTS
3.1 Timing (phenology) of migration and counts of Barnacle geese in the Tenna,
Sør-and Nord-Herøy area.
Arrivals of Barnacle geese are influenced by various factors including daylength
(which triggers migration) and weather (which determines departures from the
Solway and thereby arrivals in Norway).
Table 1. Arrival date, date of peak count and peak numbers of Barnacle geese in the
Tenna, Sør- & Nord-Herøy area 1994 – 2002.
Year
1994
1995
1996
1997
1998
1999
2000
2001
2002
Arrival date (if
known)
21st April
21st April
25th April
22nd April
29th April
22nd April
Date of peak count Peak count
9th May
7th May
7th May
11th May
14th May
16th May
13th May
9th May
13th May
3140
3050
1930
2265
2120
1631
1849
1850
2100
First arrival date (Table 1) in the Herøy area is considered here to be the date when
local residents first noted flocks of Barnacle geese. As small flocks are likely to be
missed then the date of first arrivals may be earlier than that shown in Table 1.
Around 21st or 22nd April would appear to be a normal date for first arrivals. The date
of the peak count on Herøy each spring varies greatly and is influenced by weather
conditions which determine when migrating flocks leave Britain and when they arrive
in Helgeland. The peak count tends to be between 7th and 14th May (Table 1). Note
that counts on Herøy are sometimes hampered by various factors such as visibility
and disturbance, and in some cases fluctuations in numbers may be due to incomplete
counts. Main departure date from Helgeland is largely influenced by weather
conditions, and birds tend to depart when there are either no wind or at least a
prevailing wind (own observations). Major departures from Helgeland tend to occur
after 15th May (Figs. 7 - 9).
16
3500
3000
2500
2000
1500
1000
2500
2000
1994
1995
1996
1500
1000
1997
1998
1999
500
500
0
t
25 Apr
th il
29 Apr
th i l
A
3 r pri l
d
M
7t ay
h
11 Ma
th y
15 Ma
th y
19 May
th
2 3 Ma
rd y
M
ay
21
s
21
s
t
25 Apr
th il
29 Apr
th i l
A
3 r pri l
d
M
7t ay
h
11 Ma
th y
15 Ma
th y
19 May
th
2 3 Ma
rd y
M
ay
0
Figure 7. Daily count totals for the Tenna, Sør- & Nord-Herøy area
1994 – 1996.
Figure 8. Daily count totals for the Tenna, Sør- & Nord-Herøy area
1997 – 1999.
17
2500
2000
1500
1000
2000
2001
2002
500
21
s
t
25 Apr
th il
29 Apr
th i l
A
3 r pri l
d
M
7t ay
h
11 Ma
th y
15 Ma
th y
19 May
th
2 3 Ma
rd y
M
ay
0
Figure 9. Daily count totals for the Tenna, Sør- & Nord-Herøy area
2000 – 2002.
18
3.2 Arrivals of new ringed individual Barnacle geese in the Tenna, Sør- & NordHerøy area
A large number of Barnacle geese from the Svalbard population have been ringed
with individually identifiable colour leg rings with engraved codes. These rings are
readable in the field at ranges of up to 250 metres with a 60x magnification telescope.
Resightings of ringed birds can also give a further clue as to the arrival of new
individuals into the area. The date of first observation for ringed individuals in the
years 2000 – 2002 inclusive are shown in Fig. 10. There are a high number of new
rings recorded during the first days of fieldwork, when all birds are considered as
“new” (ie. it is expected to find mostly new rings during the first days of fieldwork).
Peaks later in the season reflect new arrivals into the area, either from the wintering
grounds or from staging sites further south in Norway. The observations of first
resightings for ringed individuals most probably reflect new arrivals from Britain as
the increases in new rings tie in well with departures from the Solway Firth and
subsequent new arrivals on Herøy (Figs. 11 - 13).
60
2000
2001
2002
50
40
30
20
10
0
26.4.
28.4.
30.4.
2.5.
4.5.
6.5.
8.5.
10.5.
12.5.
14.5.
16.5.
18.5.
20.5.
22.5.
Figure 10. Number of new ringed individuals recorded in the Tenna, Sør-Herøy and
Nord-Herøy area during spring 2000 – 2002. (Data taken from Shimmings & Isaksen 2000,
2001, 2002).
19
2000
45
1800
40
1600
35
1400
30
1200
25
1000
20
800
count
resightings
15
600
10
200
5
0
0
26
.4
.
28
.4
.
30
.4
.
2.
5.
4.
5.
6.
5.
8.
5.
10
.5
.
12
.5
.
14
.5
.
16
.5
.
18
.5
.
20
.5
.
22
.5
.
400
Figure 11. Number of new ringed individual Barnacle geese recorded in the Tenna, Sør& Nord-Herøy area compared with total counts spring 2000.
50
1800
45
1600
40
1400
35
1200
30
1000
25
800
20
600
15
400
10
200
5
0
0
count
resightings
26
.4
.
28
.4
.
30
.4
.
2.
5.
4.
5.
6.
5.
8.
5.
10
.5
.
12
.5
.
14
.5
.
16
.5
.
18
.5
.
20
.5
.
22
.5
.
2000
Figure 12. Number of new ringed individual Barnacle geese recorded in the Tenna, Sør& Nord-Herøy area compared with total counts spring 2001.
20
60
2500
50
2000
40
1500
30
1000
count
resightings
20
500
10
0
26
.4
.
28
.4
.
30
.4
.
2.
5.
4.
5.
6.
5.
8.
5.
10
.5
.
12
.5
.
14
.5
.
16
.5
.
18
.5
.
20
.5
.
22
.5
.
0
Figure 13. Number of new ringed individual Barnacle geese recorded in the Tenna, Sør& Nord-Herøy area compared with total counts spring 2002.
Prior to the implementation of the Herøy plan the numbers of Barnacle geese steadily
increased from year to year, although the maximum numbers present was also
influenced by other factors including suitable conditions to commence migration from
the wintering grounds. In 3 of the 4 years prior to 1996 there were counts in excess of
3000 individuals (in 1992, 1994 and 1995) whereas peak numbers since 1996 have
rarely exceeded 2000 individuals (Fig. 14).
3500
max. no. counted
3000
2500
2000
1500
1000
500
0
1992 1993 1994 1995 1996 1997 1998 1999 2000 2001 2002
Year
Figure 14. Maximum numbers of spring-staging Barnacle geese counted on Tenna, Sørand Nord-Herøy 1992-2002 (from Shimmings & Isaksen 2002).
21
Daily counts were made each evening between 18:00 – 21:00hrs in the Herøy area,
following a standardised route. Counts were made in three main areas, these being
Tenna, Sør-Herøy and Nord-Herøy (Fig. 15).
NORDHERØY
RSØ ØY
R
HE
A
NN
E
T
Figure 15. Map of count areas on Tenna, Sør- & Nord-Herøy.
Total numbers of Barnacle geese have decreased in all areas (Tenna, Sør-Herøy and
Nord-Herøy) during the last three seasons (Figs. 16 - 24). Only counts from the period
5th - 15th May are shown in these figures, as on these dates there were good counts in
almost all of the years 1994 – 2002. The most marked decrease in total numbers of
Barnacle geese is on Tenna, from a peak of just under 1600 geese in the period 199496 to just under 800 birds in the period 2000-02, i.e. the area now supports 50% of the
goose numbers that used to feed there (Figs. 16 - 18).
22
1600
1400
1200
1000
1994
800
1995
600
1996
400
200
5.
5.
6.
5.
7.
5.
8.
5.
9.
5.
10
.5
.
11
.5
.
12
.5
.
13
.5
.
14
.5
.
15
.5
.
0
Figure 16. Numbers of Barnacle geese counted on Tenna 1994 – 1996.
1600
1400
1200
1000
1997
800
1998
600
1999
400
200
9.
5.
10
.5
.
11
.5
.
12
.5
.
13
.5
.
14
.5
.
15
.5
.
8.
5.
7.
5.
6.
5.
5.
5.
0
Figure 17. Numbers of Barnacle geese counted on Tenna 1997 – 1999.
1600
1400
1200
1000
2000
800
2001
600
2002
400
200
5.
5.
6.
5.
7.
5.
8.
5.
9.
5.
10
.5
.
11
.5
.
12
.5
.
13
.5
.
14
.5
.
15
.5
.
0
Figure 18. Numbers of Barnacle geese counted on Tenna 2000 – 2002.
23
1800
1600
1400
1200
1994
1000
1995
800
1996
600
400
200
9.
5.
10
.5
.
11
.5
.
12
.5
.
13
.5
.
14
.5
.
15
.5
.
8.
5.
7.
5.
6.
5.
5.
5.
0
Figure 19. Numbers of Barnacle geese counted on Sør-Herøy 1994 – 1996.
1800
1600
1400
1200
1000
800
600
400
200
0
1997
1998
5.
5.
6.
5.
7.
5.
8.
5.
9.
5.
10
.5
.
11
.5
.
12
.5
.
13
.5
.
14
.5
.
15
.5
.
1999
Figure 20. Numbers of Barnacle geese counted on Sør-Herøy 1997 – 1999.
1800
1600
1400
1200
2000
1000
2001
800
2002
600
400
200
0
5.5. 6.5. 7.5. 8.5. 9.5. 10.5. 11.5. 12.5. 13.5. 14.5. 15.5.
Figure 21. Numbers of Barnacle geese counted on Sør-Herøy 2000 – 2002.
24
600
400
1994
1995
1996
200
9.
5.
10
.5
.
11
.5
.
12
.5
.
13
.5
.
14
.5
.
15
.5
.
7.
5.
8.
5.
5.
5.
6.
5.
0
Figure 22. Numbers of Barnacle geese counted on Nord-Herøy 1994 – 1996.
600
400
1997
1998
1999
200
0
5.5. 6.5. 7.5. 8.5. 9.5. 10.5. 11.5. 12.5. 13.5. 14.5. 15.5.
Figure 23. Numbers of Barnacle geese counted on Nord-Herøy 1997 – 1999.
600
400
2000
2001
2002
200
0
5.5. 6.5. 7.5. 8.5. 9.5. 10.5. 11.5. 12.5. 13.5. 14.5. 15.5.
Figure 24. Numbers of Barnacle geese counted on Nord-Herøy 2000 – 2002.
25
3.3 Goose scaring methods used in the Tenna, Sør- & Nord-Herøy area and their
effects on geese.
Many different techniques have been tried in an attempt to regulate area use in most
countries where geese come into conflict with agriculture. As the Svalbard Barnacle
goose population is protected from hunting throughout it’s range, then non-lethal
methods have been employed in attempts to scare geese from intensively managed
fields and other habitats where they are considered to come into conflict with farming
interests.
Several methods to scare feeding flocks of Barnacle geese have been tried on both
Tenna and Sør-Herøy (and to a lesser degree on vulnerable fields on Nord-Herøy).
These include both active as well as passive methods:
Active scaring:
• physical chasing of flocks.
• use of signal flares / signal pens.
• firing of blank shots.
Passive scaring:
• use of coloured tape stretched across fields.
• use of gas guns.
• use of scarecrows.
• use of balloons and kites.
Physical chasing
Description:
Physical chasing took several forms. Most typical was to approach the birds in a car
or tractor, and either walk or run towards grazing goose flocks. Alternatively use of a
car/tractor horn was employed.
During the spring stgaing period in seasons 1997 – 2000 a co-ordinated, round the
clock scaring regime was maintained, whereby geese (of all species) were regularly
chased from within the scaring zone. Scaring intensity was less in 2001, and in 2002
there was no co-ordinated scaring. However, in 2002 a few farmers were seen check
fields for grazing geese on a regular basis, and chased any flocks present.
Effects:
Physical chasing of goose flocks is perhaps the best method of scaring as the
appearance of a person is unpredictable, as are the actions of such a person. By
repeatedly chasing goose flocks until they move to the refuge zone, one can ensure
that geese are in areas where they can then graze undisturbed. All observed
disturbances of feeding goose flocks and the outcome of scaring from either human
activities or from other bird and animal species have been noted each spring in the
period 1996 – 2002 (Table 2).
26
Table 2. Summary of observed scaring incidents and their outcome 1996 – 2002.
moved
from:
refuge
scare
scare
refuge
refuge
scare
moved to: chased shots flare car/tractor birds
14
5
1
8
57
refuge
2
scare
1
1
1
8
5
refuge
1
scare
2
3
8
unknown 7
1
1
4
1
unknown
22
9
4
23
73
total:
cat boat aircraft walker/jogger unknown total
1
1
4
5
21
117
1
3
6
2
1
1
6
26
2
2
5
3
3
26
7
2
3
8
8
35
187
Note that the above table is not a complete summary of all scaring incidents, but
includes those direct observations where cause and outcome were observed under
fieldwork. Many scaring episodes may well go undetected, and there are numerous
occasions when a flock takes to the wing without the reason(s) being clear.
Various other bird species have been observed to scare flocks of Barnacle geese
including the following species: Grey heron Ardea cinerea, White-tailed eagle
Haliaeetus albicilla, Golden eagle Aquila chrysaetos, Gyr falcon Falco rusticolis,
Peregrine falcon Falco peregrinus, Eurasian curlew Numenius arquata, Herring gull
Larus argentatus, Common raven Corvus corax, and Hooded crow Corvus corone.
Most are large winged species. Three of the above bird species have been seen to take
Barnacle geese in Helgeland (White-tailed eagle, Gyr falcon, Peregrine falcon), and a
fourth species (Golden eagle) is also a potential predator (own observation of Golden
eagle taking Barnacle geese on Gotland, Sweden in 1997).
It is unfortunate that there are so many human disturbances to feeding Barnacle geese
within the refuge area. As data in Table 2 shows, most of the disturbances to geese in
the refuge area is deliberate (chasing, shooting, flares) and accounts for 16% of all
observed incidents. Disturbance from passing cars, tractors, aircraft, and walkers can
be considered as incidental and unintentional disturbance (although some of the
observations of scaring from passing vehicles may have been intentional scaring
attempts).
Signal flares / signal pens
Description:
A bright flare is shot from a signal gun or signal pen over flocks of feeding geese.
Effects:
Signal flares and signal pens seem to be an effective visual way of scaring Barnacle
geese. On all occasions where this method was used, the whole flock of Barnacle
geese took flight immediately (Table 2).
27
Blank shots
Description:
Use of shotgun cartridges that do not contain any pellets fired over flocks of feeding
geese. This creates a loud bang.
Effects:
Firing of blank shots is one audible method to scare flocks of Barnacle geese, and was
often used as a deterrent in the Herøy district. Shooting with blank cartridges did not
necessarily result in flocks moving far, and it was sometimes necessary to fire
repeated shots to move feeding flocks of geese. Not all incidents where this method
has been used are shown in Table 2 due to the fact that the method was much used at
night, when the outcome was difficult to assess.
Coloured tape stretched across fields
Description:
Reels of plastic tape are stretched between posts positioned in intensively managed
fields (used for either grazing or for production of hay and silage). The distance
between the rows of coloured tape varied greatly from place to place. After strong
winds the tape often broke loose and blew around like coloured streamers, perhaps
acting as a better deterrent than motionless strips of tape.
Effects:
The most frequent type of static scaring device used in the area is coloured plastic
tape stretched between fenceposts across fields. This method seemed to work well
during the first two to three years, but Barnacle geese soon became accustomed to the
tape and, wherever possible, have learned to land on open areas of grassland not
covered by tape and then to walk under the rows. Both direct observations of feeding
flocks as well as counts of droppings show that coloured tape is however at least
partly effective at detering Barnacle geese.
In order to measure the effects of scaring tape on Barnacle geese, counts were made
of the density of droppings for a selected sample of fields. Both fields with and
without tape were surveyed. Random sampling was carried out along transects, with
points counted at 10 metre intervals. Droppings were counted in quadrats of 4 square
metres. These counts were carried out towards the end of the spring staging period,
when most Barnacle geese had left the area.
In all years there were higher densities (droppings per square metre) in areas where
there was no scaring tape compared to areas with tape (Fig. 25). In cases where
droppings were noted under tape, then they were often relatively old, dried-up
excrements which in many cases originated from after the first Barnacle geese had
arrived in Herøy, but before scaring devices were in place. For all years and all grass
types on agricultural fields combined there was an average of 0.75 droppings per
square metre on areas with goose scaring tape, compared to 5,05 droppings per square
metre for areas without any tape (Fig. 26). Thus it is apparent that scaring tape is
28
effective in keeping Barnacle geese off areas where they are not wanted (i.e.
agricultural grasslands).
mean no. droppings per sq. m.
16
14
12
10
with tape
without tape
8
6
4
2
0
1997
1998
1999
2000
2001
2002
year
Figure 25. Mean number of Barnacle goose droppings per square metre counted each
year in areas with and without scaring tape in the Tenna and Sør-Herøy area 1997-2002.
mean no. droppings per sq. m.
6
n = 208
5
4
3
2
1
n = 321
0
with tape
without tape
Figure 26. Summary of mean number of Barnacle goose droppings in areas with and
without scaring tape on Tenna and Sør-Herøy for all years 1997 - 2002 combined. The
sample size (n) refers to the total number of ground points sampled.
29
One situation where geese can become accustomed to scaring tape is when it is placed
near a roosting site. In 2002 tape was set up on the shoreline beside a bay used for
roosting. The geese simply wandered up to the saltmarsh edge and under the tape to
feed on the lush vegetation. This suggests that the geese can quickly learn that there is
no danger in feeding under tape, particular if it is positioned in areas close to where
geese feel safe (i.e. beside traditional roosting sites).
Gas guns
Description:
A burst of pressurised gas is released from a cylinder at pre-set intervals, thereby
creating a loud bang.
Effects:
The effect of gas guns has been measured by counting droppings along transects
radiating out from the nozzle.
In both May 2000, 2001 and 2002 counts of dropping density were made along
transects radiating from the nozzle of gas cannons. These counts were made towards
the end of the staging period. Droppings were counted along transects radiating from
the nozzle of the gas gun, at intervals of 5 metres. Droppings were counted in
quadrats of 4 square metres. Only those cannons that were known to have functioned
throughout the fieldwork period were included in these samples (cannons often
stopped as they ran out of gas, and it often took several days before the cylinder was
replaced).
In May 2000 there were two cannons that were fully operative throughout the study
period (both on Sør-Herøy, in fields with site codes 2603G and 2603K). In 2001 only
one cannon was fully operative throughout the study period (on Tenna, at site code
2505S). In 2002 there were in fact two cannons in operation throughout the study
period (at site 2505S on Tenna and site 2603H on Sør-Herøy). However, the cannon
on Tenna was removed on the morning when it was intended to carry out samples
along transects, such that data was only collected from the site on Sør-Herøy.
In all the three years 2000 – 2002, the average number of droppings per square metre
increased the farther away from the nozzle that the sample was made (Figs. 27 - 29),
suggesting that gas cannons are at least partly efective in deterring Barnacle geese
from feeding at a particular site. However, as Figs. 27 - 29 clearly show, the number
of droppings per square metre dropped at various points along the transects when one
was farther from the nozzle. This is probably due to the fact that at greater distances
from the cannon nozzle there were other factors that presented a perceived threat to
geese, such as trees, hillocks, or other objects which could conceal predators.
Barnacle geese are rather accustomed to gas guns, such that their effectiveness must
be questioned. Where gas guns have been used on the wintering grounds Barnacle
geese have been observed feeding under the nozzle on several occasions. Indeed, this
is the most expensive method employed to scare geese and is probably not costeffective.
30
30
2603G
25
2603G
20
2603G
15
2603K
10
2603K
5
16
5
14
5
12
5
10
5
85
65
45
25
0
5
No. of droppings per sq. m
35
Distance from gas cannon (m)
No. of droppings per sq. m.
Figure 27. Number of Barnacle goose droppings counted along transects radiating out
from gas cannons on two fields in the Høgtun/Solheim area, Sør-Herøy 19th May 2000.
From Shimmings & Isaksen 2000.
14
12
10
2505S
8
2505S
6
2505S
4
2505S
2
0
10
20
30
40
50
60
Distance from cannon (m)
6
5
4
2603H
3
2603H
2
2603H
1
11
0
95
80
65
50
35
20
0
5
No. of droppings per sq. m.
Figure 28. Number of Barnacle goose droppings counted along transects radiating out
from a gas cannon on one field in the Dammen area, Tenna 19th May 2001.
Distance from cannon (m)
Figure 29. Number of Barnacle goose droppings counted along transects radiating out
from a gas cannon on one field in the Høgtun area, Sør- Herøy 19th May 2002.
31
Scarecrows
Description:
Several different types of scarecrow were used, including both stationary types as
well as types where the “limbs” were free to move in the wind. All scarecrows used in
the area were home-made.
Effects:
Scarecrows have a long tradition of use in agriculture as a means of scaring birds.
Quite how effective these actually are can be questioned. On Tenna and Sør-Herøy
the method has been used to a limited degree, and almost always in conjunction with
other types of scaring. This makes it difficult to interpret the effect of scarecrows on
Barnacle geese. However, direct observations suggest that they are most effective
when moved on a regular basis. Scarecrows with movable arms and legs that blow
around in the wind also seem to cause birds more distress than completely static
versions (own observations).
Helium-filled balloons, kites etc
Description:
Balloons or kites attached to e.g. fenceposts, such that they can blow around in the
wind. Little used in the study area.
Effects:
As helium-filled balloons have been little used in Helgeland, it is difficult to draw
conclusions as to their effect.
Kites have never been seen to be used as a scaring method in Helgeland during the
study period. In one area of north-west Scotland, kites attached to fence posts seemed
to act as a deterrrent against feeding flocks of Greylag geese Anser anser (own
observations).
32
3.4 The effects of the Barnacle goose management plan on goose distribution in the
Tenna, Sør- & Nord-Herøy area.
One of the most important aims of the local management plan from an agricultural
point of view is to reduce reduce the number of grazing Barnacle (and other) geese in
areas where they come into conflict with agricultural interests. With that in mind,
refuge and feeding zones were established on both Tenna and Sør-Herøy in 1996
(Fylkesmannen i Nordland 1996 – see Figure 6 in section 1.3). Management schemes
where refuge zones have been created have been found to be effective in influencing
goose distribution in other European countries (van Roomen and Madsen 1991). A
simple (and well established) way of measuring the effects of the management plan
on goose distribution is to count the number of flocks and their size both within and
outside the refuge zones. This grazing intensity can be expressed as number of goose
days where:
1 goose day = (number of geese) x (number of days).
Where there are several repeat counts from the same area on the same day the number
of goose days is calculated as the mean flock size multiplied by the number of days.
The percentage of total goose days per season in the two areas (scaring zone and
refuge zone) has altered in the period 1993 to 2002, with an increase in goose usage in
the refuge zone and thereby fewer goose days in the scaring zone (Fig. 30). Prior to
management (1993 – 1995) there were around 60% of the feeding Barnacle goose
flocks in what became the refuge zone, to the current situation where around 85% of
the geese are feeding in the refuge area. Local farmers have reported an increase in
both silage and hay yields since the management plan came into effect, due to a
reduction in grazing pressure on agricultural fields.
100
80
%
60
40
20
2
1
20
0
0
20
0
9
20
0
8
19
9
7
19
9
6
19
9
5
19
9
4
19
9
19
9
19
9
3
0
Year
Figure 30. Proportion (%) of barnacle geese using refuge zones (grey) in the Tenna, Sør& Nord-Herøy area before (1993 – 1995) and after (1996 – 2002) implementation of the
management plan. The proportion is expressed in terms of goose days.
33
300
250
200
150
100
50
2
20
0
0
9
1
20
0
20
0
19
9
8
19
9
7
19
9
5
6
19
9
19
9
4
19
9
19
9
3
0
Figure 31. Mean flock size for Barnacle gese on Tenna, Sør- & Nord-Herøy 1993 – 2002.
Mean flock size has decreased since the start of the new management scheme (Fig.
31). There are few large flocks in the refuge zone. Prior to management the geese
assembled in large flocks on agricultural land during periods of least human activity
such as late evenings and early mornings (Black et al. 1991) as well as in the middle
of the day during periods of heavy rain when disturbance was at a minimum
(Shimmings & Isaksen 1999, 2000). Since the implementation of the local
management plan on Tenna and Herøy (Fylkesmannen i Nordland 1996) Barnacle
geese rarely have the opportunity to build up large flocks on agricultural land, as they
are often scared before numbers have built up (Shimmings 1998). Thus the total
number of goose days for individual fields within the scaring zone has decreased
considerably such that grazing pressure is generally less for each field (although this
is probably also dependent upon both grass type and age of crop).
Tenna, Sør-Herøy and Nord-Herøy have been divided into smaller compartments (or
sites) and each site has been given it’s own unique code such that the actual areas
used by individually ringed Barnacle geese can be recorded in a standardised and
systematic way. In addition, habitat type, including the predominant grass types for
each site has been recorded. Thus one is able to see if individual geese that are used to
feeding on intensive agricultural fields have continued to use such areas after the
management plan was implemented (Fig. 32).
None of the pairs of geese in this sample were exclusively feeding on sheep-pastures
and coastal areas – all were seen at least once on intensively managed agricultural
fields. One can imply that they have a “taste” for intensively managed grasses.
However, some pairs that continued to be observed in the Tenna & Herøy area after
co-ordinated scaring was started in 1996 have not since been recorded on intensively
34
managed grasslands, although they are still present in the study area. In actual fact, as
it took a season before all landowners were active in scaring, then 1997 may be
considered as the first year when scaring became most effective. Of the 71 pairs for
which there is data from both before and after the management plan was
implemented, 13 pairs were last seen using agricultural areas before either 1996 or
1997, 20 pairs were seen on agricultural fields both before and after management,
whereas 13 pairs that had not previously been noted using agricultural fields were
seen using such habitats for the first time after 1996 and 1997. Direct observations do
suggest that Barnacle geese on Tenna and Herøy will attempt to graze on agricultural
fields provided that they are left undisturbed. Geese probably “learn” where the most
profitable food resources are. When the risks of disturbance are minimal, individuals
probably utilise the available resources as best they can. In other words, without
scaring, Barnacle geese will feed on agricultural fields whenever possible.
As flocks of Barnacle geese have been scared from agricultural areas on Tenna and
Sør-Herøy then they have had to feed at alternative sites outside the scaring zone.
Many of the sites used by grazing geese in the refuge zone have supported geese since
the 1980’s at least. However, as a result of intensive scaring, and the refuge areas
probably being filled to capacity, Barnacle geese were forced to find new areas such
as several areas where they were not recorded prior to 1996. This included sites on
Nord-Herøy. The geese use both areas where they come into conflict with farming
interests (agricultural fields at Hokleppan, Vang and Grindstrand) as well as areas
where they do not present a problem (coastal areas between Grindstrand to
Kvikkleirøyan).
Count data reveals that there was a sharp increase in the proportion of Barnacle geese
using Nord-Herøy from the first observations in 1996, therafter levelling off and
falling slightly (Fig. 33). The falling proportion in numbers using Nord-Herøy may be
a result of less intensive scaring in both May 2001 and especially in May 2002. Geese
may also have become accustomed to scaring in other areas, such that they are less
likely to be “forced” to graze on Nord-Herøy (Nord-Herøy probably acts as a “spillover” area for birds displaced from Tenna and Sør-Herøy (Shimmings & Hatten
1998). Ring resightings show that birds feeding on Nord-Herøy have come from both
Tenna and Sør-Herøy, with the largest proportion from the latter site (Table 3). Most
of the ringed pairs that moved from other sites to Nord-Herøy were of course seen on
Nord-Herøy for the first time in the first years after management, when the chance of
a new individual being found was greatest (Table 4). Note that no ring resightings
were made on Nord-Herøy in 1996, the year when birds were first noted there. Ringed
pairs that have fed on Tenna and Sør-Herøy in previous years continue to be seen for
the first time on Nord-Herøy, so it is clear that new individuals are moving to this site.
The botanical value of the Kvikleirøyan area is such that it has newly been declared a
nature reserve there, and such protection must surely be of benefit to grazing Barnacle
geese. In order that Kvikleirøyan is as attractive to Barnacle geese as possible it will
be important to continue grazing by cattle at least at the present level.
35
bird
$HT
$PB
$UZ
*6V
*9Y
*AS
*AX
*AZ
*CDS
*CH
*ERK
*NBV
*NXS
*NYL
*PB
*PBS
*PSJ
*PTH
*SAS
*SSD
*SUL
*SYJ
*SZT
*TCV
*TDP
*TY
*UIA
*UIF
*ULC
*UNS
*UVH
*UXV
*VBV
*VC
*VCN
*VDV
mate 94 95 96 97 98 99 00 01 02
UNR
UNR
UNR
UNR
UNR
UNR
UNR
UNR
>BL
*PZT
UNR
*NCN
UNR
*NXL
UNR
metal
*NUF
UNR
*VBZ
*SVV
UNR
*SYT
UNR
UNR
UNR
UNR
*UIV
UNR
*ULI
UNR
UNR
UNR
*VCJ
UNR
*VDF
UNR
bird
*VFB
*VFP
*VFX
*VJT
*VPF
*VYS
*XJN
*ZD
>6V
>7B
>ABU
>AFI
>AIH
>ANJ
>AXA
>AXS
>AXU
>AXV
>CCB
>CIC
>DCD
>DDT
>DDZ
>DJS
>DNA
>DPD
>DZC
>FL
>HI
>HL
>IYI
>PN
>PU
>SA
>UF
mate 94 95 96 97 98 99 00 01 02
UNR
UNR
UNR
UNR
UNR
>DCL
*XJX
UNR
UNR
UNR
UNR
>PFT
>VD
UNR
>ATN
>CNU
>CSI
>AZC
UNR
UNR
>DCT
>??V
UNR
UNR
>LA
>DPF
UNR
UNR
UNR
UNR
>JBI
UNR
>TC
UNR
UNR
Figure 32. Habitat usage for pairs of Barnacle geese seen in several seasons in the
Tenna, Sør- & Nord-Herøy area, both in years without co-ordinated scaring (1994 &
1995) and in years with co-ordinated scaring (1996 onwards).
Key:
Black = seen at least once on agricultural fields in season
Grey = seen only on marginal habitats e., sheep pastures & caostal zone in season
White = not seen in season
36
45
40
35
% of
seasonal
max.
% of daily
total
%
30
25
20
15
10
5
02
20
00
20
98
19
96
19
19
94
0
Year
Figure 33. Proportion of
Barnacle geese feeding on
Nord-Herøy 1994 - 2002.
(Percentage
of
seasonal
maximum is the proportion of
geese using Nord-Herøy on the
date of the highest count each
season. Percentage of daily total
is the mean percentage (goose
days) based upon all coordinated counts in the Tenna,
Sør-Herøy and Nord-Herøy
area).
Table 3. Site where pairs of Barnacle geese fed in years before moving to Nord-Herøy.
Tenna Sør-Herøy
8
no. of pairs
41
both sites (Tenna & Sør-Herøy)
14
Table 4. Year when known pairs of Barnacle geese were first recorded using sites on
Nord-Herøy.
Year
1997
1998
1999
2000
2001
2002
No. of pairs seen for first time on NordHerøy
6
22
14
7
9
5
37
3.5 The effects of fertilising of alternative feeding sites on Tenna and Sør-Herøy.
Two areas in Herøy kommune have been fertilised in an attempt to provide better
grazing for Barnacle geese (Fig. 34). The two sites (Langvalen on Tenna and Svinøya
on Sør-Herøy) have been fertilised when conditions have allowed (i.e. when the
ground is hard enough to allow a tractor to be driven and the weather is good). Thus
timing of application of fertiliser has varied, as apparently has the amount of fertiliser
used. Unfortunately, data on the precise timing of fertilising was not made available
for this study.
Svinøya
Refuge zone
Langvalen
Figure 34. Location of two sites that were fertilised in an attempt to improve grazing
quality.
38
Goose count data has been used to assess the effect of fertilising on goose
numbers in the two fertilised areas. Langvalen is mainly used by Barnacle geese in
early morning and late evening, whereas Svinøya is mainly used in the middle of
the day. For a large part of the time that geese are seen on Svinøya they are in fact
resting, rather than feeding.
One would expect that an increase in fertiliser should lead to an improvement in
grazing quality and that this should in turn lead to an increase in usage by
Barnacle geese. However, the results contradict this theory and the numbers of
grazing geese have in fact fallen at both sites. Both the total number of goose days
(Fig. 35) as well as the highest counts (Fig. 36) for each of these areas have in fact
declined in the period 1994-2002. The percentage of the total number of Barnacle
geese on the highest count for each season has also declined (Fig. 37), which also
suggests that these two areas are less used by geese since they have been
fertilised. Both areas are within the refuge zone, such that there is little deliberate
disturbance of grazing goose flocks, so disturbance is probably not a factor
affecting goose usage at these two sites.
Possible explanations for the decline in goose numbers at both Langvalen and
Svinøya may be that the wrong type or amount of fertiliser is applied or that the
timing of application may be wrong. It may also be the case that grazing
conditions at other sites in the area are better for geese than the situation at either
Langvalen or Svinøya, and that these two sites may therefore not be so suitable for
managing to attract Barnacle geese.
It is unknown at present what type(s) of fertiliser have been applied to these two
areas. In experimental trials in Scotland, Patterson & Fuchs (1991, 2001) found
that the application of nitrogenous fertiliser in early spring increased the
attractiveness of an area for geese.
39
4000
3500
3000
2500
2000
1500
1000
500
0
19
Svinøya
Langvalen
93 994 995 996 997 998 999 000 001 002
1
1
1
1
1
1
2
2
2
Figure 35. Total number of Barnacle geese, expressed as goose days in two fertilised
areas (Svinøya & Langvalen). Trend lines are shown (solid lines for Svinøya, dotted lines
for Langvalen).
Svinøya
02
20
01
00
20
99
20
98
19
97
19
19
96
95
19
19
94
Langvalen
19
19
93
1400
1200
1000
800
600
400
200
0
Figure 36. Highest Barnacle goose count in two fertilised areas (Svinøya & Langvalen).
Trend lines are shown (solid lines for Svinøya, dotted lines for Langvalen).
40
35
30
25
% Svinøya
20
% Langvalen
15
10
5
0
1993
1998
Figure 37. Highest counts of Barnacle geese in two fertilised areas (Svinøya and
Langvalen) expressed as the percentage of the highest counts for years 1994 – 2002).
Trend lines are shown (solid lines for Svinøya, dotted lines for Langvalen).
40
3.6 The effects of burning of vegetation on goose distribution.
Deliberate and controlled burning of areas of vegetation in order to reduce the amount
of long, rank vegetation which should provide better grazing conditions for Barnacle
geese who can then feed on the shorter new grass shoots.
Only one site, to the south of Dammen on Tenna, on the west side of the main road,
has been burned to provide new grazing for geese. Vegatation in this area was first
burned in 1998, and has been used by Barnacle geese. The area is unfortunately
difficult to count as much of the area is hidden from the main road by a mound.
Numbers of Barnacle geese fluctuate greatly at this site, and the highest count was in
fact during the same year as the initial burning (Table 5). There is no obvious trend in
numbers for this site.
One factor which may affect numbers of Barnacle geese at the site which was burned
is the fact that it is actually just within the scaring zone. In addition, a holiday cabin
was built beside this site and first used in 2001. Disturbance from human activities
may affect usage of this site by geese in future years.
Table 5. Maximum numbers of Barnacle geese counted in spring 1998 – 2002 in an area
south of Dammen on Tenna, where vegetation was burned in 1998.
Year
1998
1999
2000
2001
2002
Maximum count
118
19
43
15
60
41
3.7 Movements of individually ringed geese away from Tenna, Sør- & Nord-Herøy.
There is evidence which shows that Barnacle geese have adjusted their habits since
the management plan was implemented in the Herøy area in 1996. In the Tenna, Sør& Nord-Herøy area Barnacle geese now feed to a greater degree in the refuge zones
(see section 3.4). As a result they feed to a greater degree on more marginal habitats
(sheep grazed pastures and short coastal vegetation) than prior to management (when
they feed to a greater degree on agricultural fields). During this time there have also
been increased observations of flocks at new feeding sites.
The first flocks were recorded resting in Vesterålen in May 1979 (Strann & Gullestad
unpubl. manuscript.). Since 1997 an increasing effort has been made by observers in
Vesterålen to read colour rings on Barnacle geese. A number of ringed birds
previously recorded in the Herøy district have been noted in Vesterålen in recent
years (Table 6). It is clear that an unknown proportion of “Herøy birds” have moved
to Vesterålen in recent years. Although there was an increase in the number of “Herøy
individuals” seen for the first time in Vesterålen in the springs of 2001 and 2002 (Fig
38), this may merely reflect the increase in resighting effort in Vesterålen.
Table 6. Number of individual Barnacle goose rings read in Vesterålen 1998 – 2002, and
the number of individuals that have been seen on Herøy in previous seasons.
Site
Year
Vesterålen 1998
1999
2000
2001
2002
no.individual rings
read
25
19
no. of individuals from
Herøy
3
3
75
101
132
11
14
24
Comments
plus 4 within year
movements
16
14
no. individuals
12
10
Figure 38. Year when
individual
ringed
Barnacle geese were first
recorded having moved
from
Herøy
to
Vesterålen.
8
6
4
2
0
1994 1995 1996 1997 1998 1999 2000 2001 2002
year first seen Vesterålen
42
Most of the birds that have switched from staging on Herøy to staging in Vesterålen
were found to be more than 3 years old (Fig. 39). At an age of 3 years old or more, it
is assumed that an individual is able to breed, and is likely to be paired. Thus they are
considered here to be potentially paired adults if they are over 3 years of age. Most of
the birds that moved to Vesterålen were therefore adults when they were first
observed there ( 5 out of 58 individuals) (Fig. 40).
no. of individuals
12
10
8
6
4
2
0
1
2
3
4
5
6
7
8
9 10 11 12 13 14 15 16 17
age (minimum) when first recorded Vesterålen (after
moving from Herøy)
Figure 39. Minimium age of barnacle geese that moved from Herøy to Vesterålen.
Minimum age is the age of bird during the first year the bird was recorded in Vesterålen.
60
50
total individuals
Figure 40. Proportion of
Barnacle geese that were
either non-adult or adult
in
year
when
first
recorded moving from
Herøy to Vesterålen. Nonadults are birds that are 3
years old or younger (i.e.
probably
unpaired),
whereas adults are more
than three years old.
40
30
20
10
0
non-adults
adults
Black et al. (1991) found that birds that moved from Lånan in Vega district to new
sites due to degradation in habitat quality were younger birds (i.e. less than three years
old), whereas the older and more established individuals remained at their traditional
staging site. Therefore Black et al. (1991) suggested that the younger geese were les
loyal to staging sites than older birds. It is interesting to note that it is older, and
presumably experienced individuals that have moved from Herøy to Vesterålen. One
possibility is that birds may leap-frog from site to site during the spring migration,
43
and that some individuals have discovered feeding sites in Vesterålen, and that it is
more profitable for them to stage there than on Herøy. It is possible that they have
moved to avoid disturbance from scaring on Herøy, although there is also intensive
scaring in Vesterålen, in particular in the restricted feeding areas in Sortland
Recent observations at sites between Herøy and Vesterålen (Vandve and Selvær) have
also revealed that individuals that have been seen previously in Herøy have moved to
these sites (Table 7). There is at present speculation as to whether birds stage may
leap-frog during the spring migration, until they reach Svalbard, or that they
“discover” new areas after they leave areas further south (such as Herøy). There are
however few records of within year movements to be able to assess to what extent
leap-frogging may take place.
Table 7. Number of individual Barnacle goose rings read on Vandve in 2001 and 2002,
and on Selvær in 2002, and the number of individuals that have been seen on Herøy in
previous seasons.
Site
Year
Vandve 2001
2002
no.individual rings
read
4
5
no. of individuals from
Herøy
3
0
Selvær 2002
39
9
Comments
plus 1 within year
movement
The increase in numbers of Barnacle geese in Vesterålen in recent years seems to be
both the result of the increase in the total population, as well as a shift of birds to new
areas. What are the reasons for this shift in habits? One of the likely factors is that
scaring intensity may at times be high enough to push birds into new areas. A further
factor is that the Tenna / Herøy area may have reached carrying capacity, as the geese
can no longer feed undisturbed in the best feeding areas. Certainly Tenna is unable to
support so many geese as previously. The effects of disturbance as well as changes in
land management probably influence Barnacle geese more than other species such as
Greylag Anser anser and Pink-footed Geese Anser brachyrhynchus (Owen 1973). The
first evidence that Barnacle geese moved to new areas was when counts were made on
Nord-Herøy in 1996 (Shimmings 1996), an area where they had not been recorded
feeding previously (see also section 3.4). At that time it was suspected that these
could be geese that had moved from Tenna and/or Sør-Herøy as the result of scaring.
Ring resightings on Nord-Herøy in 1997 and 1998 as well as in subsequent seasons
confirmed that these were individuals that had fed on Tenna and/or Sør-Herøy in
previous years (Shimmings & Hatten 1997, 1998). This may have been due to the
direct effects of scaring, and perhaps because geese did not get the chance to feed on
the habitats they prefered (e.g. grass pastures). The carrying capacity of the Tenna and
Herøy area is probably less now, as the geese are more restricted as regards which
areas they have access to for feeding.
44
In general, there is a tendency for Barnacle geese from northern breeding colonies on
Svalbard to stage at sites further north along the Norwegian coast than is the case for
birds from colonies further south on Svalbard (Shimmings et al. 2002). The
percentage composition of geese from colonies in northern parts of Svalbard is higher
on Andøya, Sortland and Selvær, than the percentage of birds these colonies at sites
south of Selvær (Fig. 41). The fact that Barnacle geese from certain colonies on
Svalbard are more likely to stage at particular sites during spring may mean that any
management plans in the staging areas may have more marked effects on some
colonies than others.
Andøya
Sortland
Selvær
KO
Tenna & Herøy
SA
DA
Sandvær
NO
DU
Lånan
Hysvær
Vallsjø
0%
20 %
40 %
60 %
80 %
100 %
KO = Kongsfjorden, SA = Sassendalen, DA = Daudmannsøyra, NO = Nordenskiöldskysten,
DU = Dunøyane & Isøyane
Figure 41. Percentage composition of Barnacle geese from various ringing areas on
Svalbard seen at sites along the Norwegian coast. Ring resightings are based on
observations in the period 1994–2001 except for Selvær (data from 2002). Staging sites
are arranged from Vallsjø (Vega) in the south to Andøya in the north, and breeding
colonies on Svalbard are arranged from Kongsfjorden in the north to Dunøyane and
Isøyane in the south. From Shimmings et al. 2002.
Counts are available from several sites and sources for the ten-year period 1993 –
2002 (Table 8). In the table sites are classed as either stable (no change in average
numbers during the period), increasing (an obvious increase in numbers during the
period), decreasing (an obvious decline in numbers in the period), or unclear trend
(neither an increase nor a decrease). Sites where the trend is unclear are areas where
there are few counts, or else where evidence of an increase or decrease is conflicting
(usually due to series of incomplete counts for an area).
Of 22 sites where numbers of Barnacle geese have increased during the past decade,
are 13 of these areas north of Herøy kommune (Fig. 42). All of the 9 sites where
numbers have declined during the ten-year period are either within, or south of, Herøy
kommune.
45
Table 8. Trends in numbers of staging Barnacle geese in various districts of Nordland
county during the ten-year period 1993 – 2002. Municipalities (kommune) are arranged
from north to south.
Kommune No. of sites nos. stable nos. increasing
1
1
Andøya
2
2
Øksnes
1
1
Sortland
1
1
Vågan
1
1
Røst
2
2
Bodø
1
Meløy
2
1
Rødøy
4
4
Træna
19
2
2
Herøy
3
2
Alstahaug
15
1
5
Vega
1
Brønnøy
53
3
22
Figure 42. Map of
municipalities
in
Nordland, Norway ©Statens
Kartverk,
Norsk
Eiendomsinformasjon & Asplan Viak
(NB – Øksnes is not
shown on map, but is just NW
of Sortland).
Internet AS.
46
nos. decreasing unclear trend*
1
1
6
1
2
9
9
7
1
19
3.8 The effects of the management plan in Herøy on Barnacle geese – length of
stay, body condition and reproductive success.
The average number of days Barnacle geese spend in an area can be calculated by
measuring the interval between date of mid-arrival (when 50% of the maximum has
arrived) and date of mid-departure (Gullestad et al. 1984). The mean interval between
the mid-arrival date and the mid-departure date has increased since 1996 (Table 9),
with a range of 7 to at least 9 days in the period 1994-96, and a range of at least 11 to
at least 14 days since 1996. This implies that Barnacle geese in the Herøy area were
present for longer periods after 1996.
Table 9. Interval between mid-arrival date and mid-departure date 1994-2002. See text
for an explanation of methodology.
Year
1994
1995
1996
1997
1998
1999
2000
2001
2002
mid-arrival
date
6th May
before 6th May
before 6th May
before 6th May
before 5th May
6th May
3rd May
8th May
5th May
mid-departure
date
13th May
after 15th May
after 15th may
after 19th May
19th May
after 18th May
17th May
after 19th May
17th May
interval (days)
7
>9
>9
> 13
> 14
> 12
> 14
> 11
> 12
The mean number of days a ringed individual was present varied from year to year
(Table 10), both for the population as a whole as well as for individuals seen several
years in succession (own obs.).
Table 10. Mean number of days that individually ringed Barnacle geese were present in
the Tena and Herøy area 1999 – 2002.
Year 1999 2000 2001 2002
mean no. of days seen all ringed individuals
6,19 3,50 5,58 6,37
mean no. of days excluding ringed individuals seen only on one day 9,59 6,51 8,68 9,25
Some ringed individuals were only seen on one day, or at least they were only
recorded one occasion (Fig. 43) either because they were present in flocks that were
difficult to access or because they genuinely made a short stop in the area. Regardless
of whether a ringed individual was present for one or more days, it is clear that
Barnacle geese were present for a shorter period in spring 2000 than they were in
either 1999, 2001 or 2002, although the reasons for this are unclear (Fig. 44). It
47
should also be noted that the date for mid-arrival was earlier in 2000 than in all other
years in the period 1994 – 2002.
2000
160
140
140
120
120
no. individuals
160
100
80
60
40
100
80
60
40
20
20
0
0
1
3
5
7
9
11
13
15
17
19
21
23
1
3
5
7
9
11
13
15
17
19
21
23
no. individuals
1999
no. days
no. days
2002
160
140
140
120
120
no. individuals
160
100
80
60
100
80
60
40
20
20
0
0
1
3
5
7
9
11
13
15
17
19
21
23
40
1
3
5
7
9
11
13
15
17
19
21
23
no.individuals
2001
no. days
no. days
Figure 43. Number of days that ringed individual Barnacle geese were recorded in the
Tenna, Sør- & Nord-Herøy area 1999 – 2002.
48
mean no.of days present
12
10
8
6
4
2
0
1999
2000
all ind
2001
2002
minus 1 dayers
Figure 44. Mean number of days that individually ringed Barnacle geese were present in
the Tenna, Sør- & Nord-Herøy area 1999 – 2002.
Scaring may result in an individual either spending less time in terms of number of
days in an area, as found by Madsen & Tombre (2002), or alternatively that birds may
need to remain longer in an area in order to attain optimal body condition. The latter
may be the case for Barnacle geese in the Herøy area, as the mean number of days
present has increased from 8 + 5 days in 1988 (Black et al. 1991) to 7 - > 9 days in the
period 1994-96, and to at least 11 days between 1997 and 2002.
Owen (1981) devised a method to assess body condition of wild geese in the field, by
looking at the amount of fat deposited in the abdomen (Fig. 45). During fieldwork on
Barnacle geese in the Herøy area note was made of the abdominal profiles for
approximately 100 individual Barnacle geese selected at random during flock scans
for each day. In addition, the abdominal profile for individually recognisable (i.e.
ringed) Barnacle geese was also noted whenever possible. To assess abdominal
profile one needs to look at the development of the abdomen from the side, and whilst
the goose is feeding. The scale used in studies of Barnacle geese in Helgeland ranged
from 0 (no fat deposits visible) to 7 (very round abdomen). In some extreme cases
where the individual was fatter than the scale then a score of 8 was applied. Barnacle
geese never attain an abdomonal profile score of 8 on the wintering grounds, where
Owen (1981) devised and calibrated the original scale.
Figure 45. Examples of abdominal
profile scale used for Barnacle geese.
The scale used ranges from 0 – 7, with
extremely fat birds classed as 8 (such
extreme cases are rare).
49
The mean abdominal profile for birds selected at random during flock scans on Tenna
and Herøy on 15th May was used as a measure of final body condition of Barnacle
geese. After this date there were mass departures of Barnacle geese from the area.
There has been a gradual reduction in the final abdominal profile before departure for
Barnacle geese in the Tenna / Sør-Herøy area in the period 1993-2002 (Fig. 46).
5,00
4,50
4,00
3,50
3,00
2,50
2,00
1,50
1,00
0,50
0,00
1994 1995 1996 1997 1998 1999 2000 2001 2002
Figure 46. Mean abdominal profile for Barnacle geese on 15th May 1994- 2002.
Weight gain as expressed by increase in abdominal profile scores for known (i.e.
ringed) individuals varied from season to season (Figs. 47 & 48). Although field
observations showed that a very few individuals actually lost weight during their stay
on Herøy there was always a positive increase in abdominal profile for the whole
sample.
50
4,5
4
mean AP
3,5
1994
1995
1996
3
2,5
2
3.5.
5.5.
7.5.
9.5.
13.5.
11.5.
15.5.
17.5.
19.5.
date
Figure 47. Mean abdominal profile for Barnacle geese in the Tenna, Sør- & Nord-Herøy
area from flock scans 1994 – 1996.
4,5
4
1997
3,5
mean AP
1998
1999
2000
2001
3
2002
2,5
2
3.5.
5.5.
7.5.
9.5.
11.5.
13.5.
15.5.
17.5.
19.5.
date
Figure 48. Mean abdominal profile for Barnacle geese in the Tenna, Sør- & Nord-Herøy
area from flock scans 1997– 2002.
51
5,5
0,18
0,16
0,14
4,5
0,12
0,10
3,5
0,08
0,06
2,5
0,04
0,02
1996
1998
2000
2002
.
.
.
1998
19
.5
17
.5
.
15
.5
.
1997
13
.5
11
.5
9.
5.
7.
5.
5.
5.
0,00
1994
3.
5.
1,5
1999
Figure 51. Weight gain for geese for
ringed Barnacle geese (increase in
abdominal profile from first date to last
date) 1997 – 1999.
Figure 49. Weight gain for geese from
flock scans (increase in abdominal
profile from first date to last date) 1994
– 2002.
5,5
5,5
5
4,5
4,5
4
3,5
3,5
3
2,5
2,5
2
1995
2000
1996
.
.
19
.5
.
2001
17
.5
.
15
.5
13
.5
.
11
.5
5.
9.
5.
7.
5.
5.
3.
19
.5
.
17
.5
.
15
.5
.
13
.5
.
11
.5
.
9.
5.
7.
5.
5.
5.
3.
5.
1994
5.
1,5
1,5
2002
Figure 52. Weight gain for geese for
ringed Barnacle geese (increase in
abdominal profile from first date to last
date) 2000 – 2002.
Figure 50. Weight gain for geese for
ringed Barnacle geese (increase in
abdominal profile from first date to last
date) 1994 – 1996.
52
There appears to have been a decline in the amount of fat deposits gained by Barnacle
geese in successive seasons in the period 1994 – 2002, regardless of whether one looked
at the results from flock scans each day (Fig. 49), or abdominal profile development for
known individuals (Figs. 50 - 52). This may be explained by two important factors:
1. Barnacle geese are chased more in recent seasons, at least since the local
management plan was implemented. Disturbance due to scaring results in birds
taking flight, thereby using up valuable body resources (i.e. fat reserves). A
similair result has been found in Pink-footed geese Anser brachyrhynchus subject
to disturbance at staging sites in Vesterålen (Madsen & Tombre 2002).
2. Barnacle geese are prevented from feeding on intensively managed agricultural
land. In particular, they have been actively chased from grass fields since 1996.
The agricultural fields are where the geese are able to gain the most fat (Prop &
Black 1998). As the geese have fed to a greater degree in the refuge zone, where
the habitat is of poorer quality, they are thus unable to increase their body
reserves (i.e. fat) to the same degree as before the management plan was
implemented.
Body condition during spring staging has been shown to be closely correlated with
reproductive success in geese. Geese with higher protein reserves during arrival in the
breeding grounds are more likely to produce offspring. However, birds feeding on
agricultural fields may not attain enough protein in order to be able to breed successfully,
as it is protein reserves rather than fat reserves which are important in determining
breeding success (Prop & Black 1998). Breeding success or failure for Svalbard
Barnacle geese is assessed on the wintering grounds on the Solway Firth (UK) where
regular observations are made of ringed individuals and their respective partners as well
as whether or not they have young associating (as a general rule goose families remain
together for much of the first winter).
Boyd (2000) suggested that there are, however, energetic costs of flying with a heavier
fat load, and additional risks of leaving with lower loads, and that geese probably do as
best they can given the particular feeding circumstances.
If final abdominal profile (and thereby total available body reserves) before departure
from Tenna and Herøy in the period 1994 – 2002 has dropped, then one would expect to
see a corresponding fall in the reproductive output of Barnacle geese staging in that area.
53
14
120
12
100
10
80
8
60
6
40
4
20
2
0
0
% juvs population
140
Total y produced
Total no. successful pairs
Percent juvs. Svalbard popn.
20
00
16
19
99
160
19
98
18
19
97
180
19
96
no. of young or pairs
Both the total number of young produced as well as the number successful breeding pairs
of Tenna and Herøy birds has declined in the study period (Fig. 53). The number of
young per successful pair was as high as 0.8 young per pair in 1996, but only less than
0.2 young per pair in 2000 (Fig. 54). However, the percentage juveniles in the Svalbard
population as a whole has also declined in the same time period, as an effect of density
dependent effects influencing reproductive success on the breeding grounds (Prestrud et
al. 1989).
year
young per successful pair
Percent juvs. Svalbard
popn.
No. of young per
successful pair Herøy
geese
20
00
19
99
19
98
0,9
0,8
0,7
0,6
0,5
0,4
0,3
0,2
0,1
0
19
97
18
16
14
12
10
8
6
4
2
0
19
96
% juvs winter
Figure 53. Breeding success for Barnacle geese staging in the Tenna, Sør- & Nord-Herøy
area 1996 – 2000.
year
Figure 54. Number of young per successful breeding pairs for Barnacle geese staging in the
Tenna, Sør- & Nord-Herøy area.
54
As females are more constrained in terms of energetics during migration and
reproduction (Prop et al. in press), an analysis was carried out on growth rate as
expressed by abdominal profiles for ringed individual females. Only females that were at
least three years old were selected, as this is the first age of breeding in Barnacle geese
(Black & Owen 1995). Only birds for whom abdominal profile scores at least three days
apart were selected, as these had been in the study area long enough to be able to attain
body reserves. For these females there was a strong variation between years (Fig. 55).
There was no obvious relationship between female weight gain and reproductive success
in the years 1996-2000, although factors other than weight gain during staging may have
played a part in influencing reproductive success in those years.
0,250
0,200
0,150
0,100
0,050
20
02
20
01
20
00
19
99
19
98
19
97
19
96
19
95
0,000
19
94
mean weight gain per day
(females)
0,300
year
Figure 55. Weight gain per day (as expressed by increase in abdominal profile score) for
female Barnacle geese only on Tenna, Sør- & Nord-Herøy 1994-2002.
55
4. DISCUSSION
Intensive monitoring of Barnacle geese both before the local management plan in the
Herøy district was implemented (pre-1996) and subsequently (1996 onwards) has enabled
some of the questions relating to goose management to be answered. The aims of these
analyses were to address the following questions:
Has grazing pressure in the scaring zone been reduced as the result of the Herøy
management plan?
•
Scaring has a direct effect on the distribution pattern of Barnacle geese. As
scaring takes place largely on intensively managed agricultural land, then the
geese are forced to feed on marginal land within the refuge zone). Barnacle geese
now spend more time feeding in the refuge zone than in the scaring zone. As
flocks are scared from agricultural fields where they tended to congregate in large
flocks, and are subsequently more spread throughout the area, then mean flock
size is lower than prior to the management plan coming into force.
Has grazing pressure become displced to other areas on Herøy?
•
Barnacle geese began to feed on Nord-Herøy in 1996, and numbers have
increased in that area. Resightings of ringed individuals has shown that these are
birds that have been displaced from both Tenna and Sør-Herøy.
What are the most effective scaring methods?
•
Different scaring methods have varying effects on Barnacle geese. The most
common, and perhaps cheapest, method is the use of coloured scaring tape. Tape
helps keep Barnacle geese away from fields to some degree, although as with all
other forms of scaring they inevitably become accustomed to the tape. Physical
chasing of goose flocks is however the most effective scaring method, as geese
can be chased until they settle in an area where they do not come into conflict
with agricultural interests (i.e. that they land in the refuge zone). The use of gas
guns has not proved to be very effective in keeping geese away from grasslands,
although there is less grazing pressure close to such devices than there is farther
away.
Has the management plan on Herøy contributed to the increase in use of new staging
areas along the Norwegian coast?
•
Numbers of staging Barnacle geese have increased at sites further north at the
same time that goose scaring was intensified in the Herøy district. To what extent
scaring itself has been a factor in this movement to new areas is difficult to say,
although ringed individuals that fed in the Herøy area in previous years are now
observed at sites both farther north in Helgeland as well as in Vesterålen.
56
What effects have habitat management for Barnacle geese had on goose usage?
•
Although a proven successful method in other studies, it has not been shown that
fertilising of areas to make them more attractive to Barnacle geese has been
successful in the Herøy district. Indeed there were fewer geese in two areas since
they have been fertilised than there were before treatment.
One area on Tenna was burned to improve grazing conditions. Barnacle geese graze in
this area, although the count results have proved difficult to interpret. Unintentional
disturbance occurs in the same area.
•
Do individual Barnacle geese spend more or less time in Herøy as the result of
management?
Observations on ringed individuals have revealed that Barnacle geese now spend more
time in the Herøy area than prior to the management plan. This increase in number of
days that are spent staging may be a consequence of birds trying to reach optimal body
condition before departure to Svalbard.
•
Has management on Herøy had an effect on body condition and subsequent
breeding success?
By feeding within the refuge zone, Barnacle geese attain less fat reserves than when they
feed on the rich grasslands in the scaring zone. This has an affect on body condition, and
as a result can affect the subsequent breeding success. As well as feeding on habitats
where they gain less fat reserves, Barnacle geese also use up more energy through flying
during bouts of scaring activity. This is also a reason for the lower abdominal profile
scores in recent years. Reproductive success was poorer for birds that staged on Herøy in
successive seasons 1996 – 2000. This reduction in breeding success may not be a
consequence of scaring as there was a similair trend for the whole Svalbard population.
5. RECOMMENDATIONS
Successful management of feeding areas for Barnacle geese is a complex issue,
especially as birds have established new staging sites. The establishment of new staging
sites presents new challenges as regards management of Barnacle geese in Norway. Local
management plans must be flexible enough to address any changes in distribution and
numbers of geese in a particular area, and if necessary the best methods to alleviate both
real and perceived conflicts with other interests. Experience gained during monitoring of
the local management plan in the Herøy district should be useful if any other regions are
intending on implementing their own plans, especially with regards to the fate of both the
geese themselves as well as the impact on local agricultural interests. Whether intensive
and co-ordinated scaring is the best way to alleviate the crop damage conflict is a matter
57
for continuing debate, not least as regards whether other methods such as compensation
or growing of sacrificial crops are more or less cost effective.
As has been shown, birds from different colonies have different migration strategies in
terms of choice of staging sites. As a result, management plans in different districts may
have more profound effects on birds from some colonies than others.
If scaring is to continue to be used as a tool in manipulating the numbers and distribution
of Barnacle geese in the Tenna, Sør- & Nord-Herøy area then the following
recommendations to improve the effectiveness need to be considered:
In order to be most effective, it is necessary to provide refuge zones / alternative feeding
sites such that geese can resettle in areas where they no longer come into conflict with
agricultural interests. In the Herøy area such refuge zones have been provided. Refuge
zones on Tenna and Sør-Herøy are poorer quality habitats (sheep-grazed pastures and
coastal vegetation) whereas the geese have been prevented to a large extent from grazing
on the high quality intensively managed agricultural fields. The situation is rather
different from that on the wintering grounds, where agricultural fields are managed
specifically to attract geese, or where farmers receive payments to tolerate flocks of
grazing Barnacle geese (Owen 1973, Cope et al 2002).
To be fully effective the placement and use of scaring devices ought to be altered on a
frequent basis, to reduce accustomisation by geese to the various scaring devices. As
stated earlier geese become accustomed to various devices over a period of time.
Physical chasing:
This also involves an element of surprise. An effective method for moving geese from an
area where they are undesired. Own observations suggest that geese seem to learn which
vehicles are used by people out scaring geese, such that they may rise to the air merely
upon becoming aware that a particular car is in the area.
Chasing (and other forms of scaring) should be restricted to within the scaring zone. It is
unfortunate that a number of scaring incidents take place within the refuge zone.
One very important point to bear in mind is the need to continue to scare geese from
areas where they are not welcome regardless of weather. During periods of bad weather
(e.g. rain or fog creating poor visibility) there is evidence that an increased number of
geese feed on grass fields within the scaring zone. This is almost probably in response to
reduced disturbance in the form of agricultural activity. If scaring is to be effective then
the intensity needs to be maintained during periods of bad weather. During bad weather
Barnacle geese can feed on grass fields regardles of time of day, and not just during the
peak grazing periods in the early morning and late evening.
Signal flares / signal pens:
58
These seem to be very effect at scaring geese, as there is an element of surprise in their
use i.e. a suden and unexpected flash of light overhead. However, one drawback is the
risk of fire if the flare lands on a flammable surface such as dry grass (such resulted in a
small grass fire on Tenna in 2001).
Blank shots:
Effective, as they result in a sudden, and often unexpected, loud noise.
Coloured tape stretched across fields:
Barnacle geese on Herøy seem to slowly be becoming accustomed to coloured tape.
Coloured tape should NEVER be used close to roosting areas, as this is likely to lead to
accustomisation, as geese often wander from the safety of roost sites onto nearby land. In
that way they learn to go under tape. In 2002 coloured tape was stretched across
saltmarsh beside a coastal roost site at Øverleiro (between Oterholmen and Svinøya) on
Sør-Herøy. Perhaps tape seems just like all the other rubbish that is washed up along the
tideline, which the geese appear to be accustomed to?
Distance between rows of tape may be important as there may be enough of a landing
strip to allow geese access to grazing sites where they are not wanted. If scaring tape is to
be effective, then it needs to be used across the whole field, and not just a part of the field
as is sometimes the case (own obs.). On several occasions Barnacle geese have been
recorded walking under tape from neighbouring areas without tape. If tape covers all of
the field then it is very difficult for a large flock of geese to land between the rows of
tape, although small numbers may of course succeed in walking under.
Gas guns:
Barnacle geese may be used to gas guns to a greater extent than other goose species, as
they are (or were) used on parts of the wintering grounds on the Solway Firth. In winters
1991-92 and 1992-93 Barnacle geese were seen feeding close too, and indeed under(!),
the nozzle of a gas gun which had been in place for several weeks (own unpublished
observations). In addition, Greylag geese on the island of Blomsøy(a) were seen to feed
very close to the nozzle of a gas gun after the start of the shooting season, presumably as
the field was one of the few areas on the island where shooting did not occur (Shimmings
2001a). Gas guns should be moved occasionally, as geese become used to their presence,
and are perhaps most effective when combined with other forms of goose scaring.
Scarecrows:
A method much employed, but one where geese to seem to become accustomed. Most
effective are scarecrows with moving parts e.g. with loose “limbs” that blow around in
the wind as they are probably more lifelike than an immobile solid structure. One variant
59
on the scarecrow theme is the “howling man”, an inflateable figure which rises up at
regular intervals, at the same time omitting a loud howling sound. This method was used
and seemed to work on Greylag geese in trials in 1986 (Bjøru 1987).
Helium-filled balloons, kites etc:
Little used, and apparently effective on the few occasions when they have ben used on
Herøy (usually only as leftovers from the celebrations after National Day on 17th May!).
Provided there is some wind (which tends to be the case in the study area, even on warm
days, then the balloons and / or kites can move around in the air and increase the scaring
effect of such devices.
Other methods of scaring:
A number of other methods to scare geese have not, as far as is known, been tried in the
Herøy district. This includes the use of dogs to chase geese from fields, a method which
seems to be successful on the wintering grounds (own observations). Electric fences are
also an alternative form of scaring, and have been used successfully in deterring feeding
Mute swans Cygnus olor (Kear 1963). Revolving powerful lights have also been shown
to be effective in deterring night-feeding waterfowl (Stephen 1959), although their effect
would be expected to be minimal in Helgeland where it is hardly dark during the springstaging period for Barnacle geese. In previous years models of geese taking to the air
have been used, but field trials have shown that this method is ineffective, and that geese
quickly become used to their presence (Bjøru 1987).
60
6. ACKNOWLEDGEMENTS
This report has been compiled thanks to funding from the Norwegian Directorate for
Nature Management (Direktoratet for naturforvaltning – DN). Tjøtta Rural Development
Centre (Planteforsk Tjøtta Fagsenter) helped with administration of the contract, and I
extend my thanks to Håkon Sund (centre leader) in particular.
Funding of the fieldwork which forms the basis of the analyses presented in the report
was received from the Norwegian Game Fund (viltfondet), with grants recived through
the County Governor’s Office for Nordland (Fylkesmannen i Nordland), and was in
recent years administered by Herøy municipality (Herøy kommune).
A big thank you to all those who have helped in various ways during fieldwork, either by
counting geese, reading goose rings, discussing goose problems or helping with logistics.
Amongst those who deserve special thanks are: Johan Antonsen, Johnny Bakken, Espen
Bergersen, Thomas Bjugn, Hugh Boyd, Per A. Bjørkly, Terje Bø, Tor Bønes, Thomas
Carlsen, Vidar Carlsen, Espen Dahl, Korenlius Dahl, Arild Espelien, Kirstin Fangel, Arne
Follestad, Rolf J. Forsmo, Odd and Anne-Lise Gjengaar, Arild Grønbech, Bård
Grønbech, Halvdan Hansen, Johan Hansen, Lise Hatten, Jørn Høberg, Helge Holand,
Kjell Isaksen, Åge Iversen, Helge Lenning, Magne Lenning, Jesper Madsen, Frode
Nilsen, Atle Ivar Olsen, Steinar Olsen, Tore Oppdal, Olaf Paulsen, Kjetil Pedersen,
Marina Polugod, Bjørn Røsshag, John Stenersen, Ingunn Tombre, and Trond Zahl. In
particular I wish to thank Espen, Lise and Kjell for companionship in the field,
sometimes in arduous conditions (and who know what it is like to get up at 3 o’clock in
the morning to go and look at geese!). Thank you to all the landowners on Herøy for
bearing with us, and for taking time to discuss geese and practical problems relating to
the management plan.
Background information on the population, on spring movements and counts on the
Solway Firth was provided by the respective goose officers at Caerlaverock, namely
David Patterson, Richard A. Phillips and Larry Griffin.
Ringing data was kindly provided by the Wildfowl and Wetlands Trust, with additional
data from the colonies in Kongsfjorden provided by Maarten J.J.E. Loonen at University
of Gröningen (The Netherlands). Carl Mitchell provided supplementary data on Barnacle
geese ringed in Sassendalen. Special thanks to Eileen Rees at WWT for the initial
permission to use the goose ringing and resighting data for some of the analyses in this
report.
Brian Morrell at WWT Caerlaverock kindly provided the photograph of a Barnacle goose
on the front cover. Steve Edwards kindly allowed me to use the photograph on page 9.
Finally, apologies to anyone whose name may have been inadvertadely omitted. Without
the help and cooperation of a great number of individuals much of the results in this
report would not have been possible.
61
7. REFERENCES
Black, J.M. 1998a. Conservation and management plan for the Svalbard population of Barnacle goose.
Prepared for the Directorate for Nature Management and Scottish Natural Heritage. DN-rapport 1998-2.
111 pp.
Black, J.M. 1998b. Flyway plan for the Svalbard population of Barnacle geese: A summary. Pp. 29–40 in
Mehlum, F., Black, J.M. & Madsen, J. (red.). Research on Arctic Geese. Proceedings of the Svalbard
Goose Symposium, Oslo, Norway, 23–26 September 1997. Norsk Polarinstitutt Skrifter 200.
Black, J.M., Deerenberg, C. & Owen, M. 1991. Foraging behaviour and site selection of Barnacle geese
Branta leucopsis in a traditional and newly colonised spring staging habitat. Ardea 79: 349–358.
Black, J.M. & Owen, M. 1995. Reproductive performance and assortative pairing in relation to age in
Barnacle geese. Journal of Animal Ecology 64: 234–244.
Black, J.M., Patterson, D.J., Shimmings, P. & Rees, E.C. 1999. Barnacle geese on the Solway: 1990-96.
Scottish Birds 20: 63–72.
Bjøru, R. 1987. Forebyggende tiltak mot gåseskader på dyrka jord. En undersøkelse fra Herøy i Nordland,
1985 og 1986. Rapport 2-87. Fylkesmannen i Nordland. 32 pp.
Boyd, H. 2000. Abdominal profiles of Barnacle geese Branta leucopsis at staging areas in Iceland.
Wildfowl 51: 33–47.
Bø, T, Ekker, M. & Lindgaard, A. 1998. Action plan for goose management in Norway. Pp. 19–28 in
Mehlum, F., Black, J.M. & Madsen, J. (red.). Research on Arctic Geese. Proceedings of the Svalbard
Goose Symposium, Oslo, Norway, 23–26 September 1997. Norsk Polarinstitutt Skrifter 200.
Cope, D.R., Pettifor, R.A., Griffin, L.R., & Rowcliffe, J.M. 2002. Integrating farming and wildlife
conservation: the Barnacle Goose Management Scheme. Biological Conservation 110: 113–122.
Direktoratet for naturforvaltning. 1996. Handlingsplan for forvaltning av gjess. DN-rapport 1996-2. 79
pp.
Follestad, A. & Bø, T. 1991. National report: Norway. pp. 159–162 in: van Roomen, M., & Madsen, J.
Waterfowl and agriculture: review and future perspective of the crop damage conflict in Europe. IWRB
Special Publication nr. 21.
Follestad, A. & Shimmings, P. 2001. Recent changes in the spring staging areas in Norway for Svalbard
Barnacle geese. In Patterson, I. (Ed.). Goose 2001. 7th Annual Meeting of the Goose Specialist Group of
Wetlands International, Roosta, Estonia 27 April–2 May 2001. Proceedings; Abstracts of Papers and
Posters. Wetlands International Goose Specialist Group Bulletin. No. 9, Supplement 2001.
Fylkesmannen i Nordland. 1996. Lokal forvaltningsplan for kvitkinngås på Sør-Herøy og Tenna.
Fylkesmannen i Nordland, miljøvernavdlingen. 35 pp.
Gullestad, N., Owen, M. & Nugent, M.J. 1984. Numbers and distribution of Barnacle geese Branta
leucopsis on Norwegian staging islands and the importance of the staging area to the Svalbard population.
Nor. Polarinst. Skr. 181: 57–65.
Hatten, L., Sickel, H., Norderhaug, A. & Elven, R. 1995. Vegetasjonsendringer i et kystkulturlandskap.
Ottar 207: 16–27.
62
Kear, J. 1963. The protection of crops from damage by wildfowl. The Wildfowl Trust Fourteenth Annual
Report, 1961-62: 66–71.
Madsen, J. & Tombre, I. 2002. Kortnebbgjess i Vesterålen; problemer for norsk gåseforvaltning? Ottar
239: 22–29.
Owen, M. 1973. The management of grassland areas for wintering geese. Wildfowl 24: 123–130.
Owen, M. 1981. Abdominal profile – a condition index for wild geese in the field. J. Wildl. Manage. 29:
227–230.
Patterson, I.J. & Fuchs, R.M.E. 1991. Possibilities for waterfowl reserves from changing land-use
practices. pp. 71 – 77 in: van Roomen, M., & Madsen, J. Waterfowl and agriculture: review and future
perspective of the crop damage conflict in Europe. IWRB Special Publication nr. 21.
Patterson, I.J. & Fuchs, R.M.E. 2001. The use of nitrogen fertilizer on alternative grassland feeding
refuges for pink-footed geese in spring. Journal of Applied Ecology 38: 637–646.
Prestrud, P., Black, J.M. & Owen, M. 1989. The relationship between an increasing Barnacle goose
Branta leucopsis population and the number and size of colonies in Svalbard. Wildfowl 40: 32–38.
Prop, J. & Black, J.M. 1998. Food intake, body reserves and reproductive success of barnacle geese
Branta leucopsis staging in different habitats. Pp. 175–193 i Mehlum, F., Black, J.M. & Madsen, J. (ed.).
Research on Arctic Geese. Proceedings of the Svalbard Goose Symposium, Oslo, Norway, 23–26
September 1997. Norsk Polarinstitutt Skrifter 200.
Prop, J., Black, J.M., Shimmings, P. & Owen, M. 1998. The spring range of Barnacle geese Branta
leucopsis in relation to changes in land management and climate. Biological conservation 86: 339–346.
Prop, J., Black, J.M., & Shimmings, P. In press. Travel schedules to the high arctic: barnacle geese
trade-off timing of migration with accumulation of fat deposits. Submitted to Oikos.
Rochard, J.B.A. & Kear, J. 1968. A trial to investigate the reactions of sheep to goose droppings on grass.
Wildfowl 19: 117–119.
Shimmings, P. 1996. Observations of Barnacle geese in Helgeland during May 1996. (Observasjoner av
kvitkinngås på Helgeland i mai 1996). Report to Fylkesmannen i Nordland, miljøvernavdelingen. 8 pp.
Shimmings, P. 1998. Kvitkinngås ved rasteplasser langs norskekysten - forandringer i områdebruk
medfører konflikt med jordbruksinteresser. Vår Fuglefauna 21: 11–15. (Changes in use of spring staging
areas by Barnacle geese and the effect of increased use of agricultural areas – In Norwegian with English
summary).
Shimmings, P. 2001a. Gåseregistrering i Alstahaug kommune 2001 (med tilleggsopplysninger fra 1999 &
2000). Rapport til Alstahaug kommune. 36 pp.
Shimmings, P. 2001b. Hvitkinngås – kystens gås. Ranas Dyreliv 22: 14–18.
Shimmings, P. 2002. Hvitkinngås – bestandsutvikling, trekkmønster og rasteplasser hos Svalbardbestanden. Ottar 239: 17 – 21.
Shimmings, P. & Hatten, L. 1997. Observations of Barnacle geese in Helgeland during May 1997.
(Observasjoner av kvitkinngås på Helgeland i mai 1997). Report to Fylkesmannen i Nordland,
miljøvernavdelingen. 9 pp.
63
Shimmings, P. & Hatten, L. 1998. Observations of Barnacle geese Branta leucopsis in Helgeland,
Norway, during May 1998, with emphasis on numbers and distribution in the Tenna, Sør-Herøy and NordHerøy area. (Observasjoner av kvitkinngjess Branta leucopsis på Helgeland i mai 1998, hovedsakelig i
områdene Tenna, Sør-Herøy og Nord-Herøy). Fylkesmannen i Nordland, miljøvernavdelingen. 37 pp.
Shimmings, P. & Isaksen, K. 1999. Results of fieldwork on Barnacle geese Branta leucopsis in the
Helgeland region of Norway during spring 1999. Report to Fylkesmannen i Nordland,
miljøvernavdelingen. 59 pp.
Shimmings, P. & Isaksen, K. 2000. Results of fieldwork on Barnacle geese Branta leucopsis in the
Helgeland region of Norway during spring 2000 (with selected notes from other areas). Report to
Fylkesmannen i Nordland, miljøvernavdelingen. 33 pp.
Shimmings, P. & Isaksen, K. 2001. Results of fieldwork on spring-staging Barnacle geese Branta
leucopsis on the Norwegian coast spring 2001. Report to Fylkesmannen i Nordland, miljøvernavdelingen.
42 pp.
Shimmings, P. & Isaksen, K. 2002. Results of fieldwork on spring-staging Barnacle geese Branta
leucopsis on the Norwegian coast spring 2002. Report to Fylkesmannen i Nordland, miljøvernavdelingen.
62 pp.
Shimmings, P., Isaksen, K., Griffin, L., & Loonen, M.J.J.E. 2002. Do Barnacle geese Branta leucopsis
from different breeding areas have different migration strategies. Poster to Goose 2002 Conference, Coto
Donana, Spain.
Stephen, W.J.D. 1959. Co-operative waterfowl depredation investigation. Canadian Wildlife Serv. Nov. 9.
1957: 1–13.
Strann, K.-B., & Gullestad, N. unpubl. manus. Migration of Barnacle geese Branta leucopsis in North
Norway. Submitted to Wildfowl.
van Roomen, M., & Madsen, J. (eds.). 1991. Waterfowl and agriculture: review and future perspective of
the crop damage conflict in Europe. IWRB Special Publication No. 21. 183 pp.
64