Iceland Greylag Goose
The Iceland Greylag Goose breeds in Iceland and winters almost elusively in Britain, with smaller numbers in Ireland, Norway and the Faeroe Islands. Increasingly, some birds also remain in Iceland over winter.
Early analysis of ringing data confirmed that this population of Greylag Goose was discrete from others in the Western Palearctic, including the British-breeding population. Nowadays, however, there is some overlap between the Icelandic and British birds during the winter, notably in Orkney and Caithness.
Global status (IUCN Red List of Threatened Species) Least Concern African-Eurasian Waterbird Agreement (AEWA) B1 European status (European Red List of Birds) Least Concern (Europe and EU27) The Birds Directive (European Commission) Annex II (Part A) UK status (Birds of Conservation Concern) Amber UK quarry species (Wildlife & Countryside Act 1981) Schedule 2 (Part 1); huntable during the open season
Flyway population size (CSR 8; Wetlands International 2021) 76,000 individuals GB estimate (Frost et al. 2019) 91,000 individuals UK trend (Frost et al. 2021) 25-year trend (1993/94-2018/19) = 6% decrease
10-year trend (2008/09-2018/19) = 6% decrease
Table 1. Annual estimates of the population size, percentage of young (%) and mean brood size (young per successful pair) of Iceland Greylag Goose, 2003-2020. Data are collected through the Icelandic-breeding Goose Census.
Autumn/winter Estimate of population size Percentage of young (%) Mean brood size 2020 60,061 No data collected No data collected 2019 73,355 20.1 2.17 2018 58,426 22.6 2.08 2017 60,962 19.9 1.97 2016 90,471 23.5 2.53 2015 95,403 20.4 2.73 2014 89,668 22.3 2.07 2013 88,577 22.2 2.23 2012 104,632 21.7 2.36 2011 111,558 19.6 1.92 2010 105,191 22.4 2.11 2009 105,947 21.9 2.26 2008 96,651 25.0 2.29 2007 100,630 21.7 2.61 2006 79,228 20.6 1.90 2005 95,664 22.7 2.30 2004 105,870 28.2 2.80 2003 80,802 20.5 2.73
Frost, T., G.E. Austin, R.D. Hearn, S. McAvoy, A. Robinson, D.A. Stroud, I. Woodward & S.R. Wotton. 2019. Population estimates of wintering waterbirds in Great Britain. British Birds 112: 130-145.
Frost, T.M., N.A. Calbrade, G.A. Birtles, C. Hall, A.E. Robinson, S.R. Wotton, D.E. Balmer & G.E. Austin. 2021. Waterbirds in the UK 2019/20: The Wetland Bird Survey. BTO, RSPB and JNCC, in association with WWT. British Trust for Ornithology, Thetford.
Wetlands International. 2021. Waterbird population estimates. Retrieved from http://wpe.wetlands.org/ September 2021.
Iceland Greylag Goose data presented in Table 1 (Estimate of population size/Percentage of young/Mean brood size) are licensed under the Open Government Licence 3.0 except where otherwise stated.
When you use information from this report under the Open Government Licence you must include the following attribution:
Contains Goose & Swan Monitoring Programme (GSMP) data from “WWT. 2021. Goose & Swan Monitoring Programme: survey results for Iceland Greylag Goose Anser anser. WWT/JNCC/NatureScot, Slimbridge” retrieved from https://monitoring.wwt.org.uk/our-work/goose-swan-monitoring-programme/species-accounts/iceland-greylag-goose/ © copyright and database right 2021. The GSMP is organised by the Wildfowl & Wetlands Trust (WWT) in partnership with the Joint Nature Conservation Committee (JNCC) and NatureScot with fieldwork conducted by volunteers.
The Iceland population of the Greylag Goose was confirmed as being discrete from other Greylag Goose populations in the Western Palearctic, including the British-breeding population, by early analyses of ringing data. There is, however, some overlap between these populations during the winter, notably in Orkney and Caithness. This population breeds in lowland areas of Iceland. Each autumn, birds migrate to spend the winter almost exclusively in Britain. A small number of birds also winter in Ireland and the Faeroe Islands, and others have recently been identified in southern Norway.
Flyway of the Iceland Greylag Goose
Arrival in Britain begins in early autumn, particularly in north and east Scotland. Considerable redistribution used to occur later in the winter, especially to traditional haunts further south within Scotland and to northern England. Important changes in these patterns, however, since the 1970s means this rarely happens nowadays; there has been a clear contraction of range northwards and formerly important sites, especially in southern and central Scotland, have now been abandoned. Consequent increases have been most marked on Orkney, where winter numbers have increased from c. 3,000 in the early 1990s to a peak of over 60,000 in 2010 (Mitchell 2011). From early April, birds begin to leave Britain to return to the southern lowlands and other coastal areas of Iceland (Hearn & Mitchell 2004).
As little traditional winter habitat (coastal Scirpus beds and inland fens and marshes) remains in Britain today, the species has moved inland to feed on arable farmland and improved pastures. Many of these crops are of economic value and this has brought the geese into direct conflict with farmers. Farmers have tolerated geese for many years, but concern and the number of complaints have been growing, particularly where goose numbers are high and increasing, such as Orkney.
Hearn, R.D. & C.R. Mitchell. 2004. Greylag Goose Anser anser (Iceland population) in Britain and Ireland 1960/61 – 1999/2000. Waterbird Review Series, The Wildfowl & Wetlands Trust/Joint Nature Conservation Committee, Slimbridge.
Mitchell, C. 2011. Status and distribution of Icelandic-breeding geese: results of the 2010 international census. Wildfowl & Wetlands Trust Report, Slimbridge.
Icelandic-breeding Goose Census
The Iceland Greylag Goose population is monitored through the Icelandic-breeding Goose Census; an international census undertaken in Britain, Ireland, Iceland, Norway and the Faeroe Islands. The census is undertaken annually and involves coordinated counts carried out in autumn and early winter.
Results from the census are presented in various reports which can be downloaded from the Reports & newsletter page.
Find out more about the Icelandic-breeding Goose Census
GSMP age assessments
The annual breeding success of the Iceland Greylag Goose population is monitored through age assessments that are undertaken annually throughout the autumn and early winter. Counters record the number of first winter birds present within a flock and individual brood sizes (i.e. how many young in each family group).
Results from these age assessments are presented on the ‘Latest results’ tab, and a summary table can also be found on the ‘Status summary’ tab.
Find out more about age assessments
Results for 2020/21 [September 2021]
The 61st consecutive Icelandic-breeding Goose Census (IGC) took place early winter 2020, providing information on the abundance and distribution of Iceland Greylag Geese. A full account of the census can be found in Brides et al. (2021).
In Britain and Ireland, a network of volunteer observers and professional conservation staff conducted counts over the weekend of 21/22 November. The additional three-yearly spring census, scheduled to take place in March 2021, was cancelled due to the various restrictions in place as a result of the Covid-19 pandemic; this will, instead, take place in 2022.
In Iceland, Greylag Geese were counted by aerial and ground surveys: all counts were carried out in favourable conditions. Counts in Southwest Norway took place in January rather than November: guidance from counters in Norway suggests that the winter influx of Icelandic migrants occurs in late October and early November and they remain there throughout the winter (A Follestad. pers. comm). No counts were undertaken in the Faroe Islands.
The total count was 92,582 Greylag Geese (Table 1). Following adjustments for the presence of British/Irish Greylag Geese (see Brides et al. 2021), which is significant in some areas, a population estimate of 60,061 was derived. This represented a decrease of 18.1% compared to 2019 when a population of 73,355 was estimated and is similar to the estimates in 2017 and 2018 (Figure 1).
By November, just under three-quarters of the population (71%) were found in North Scotland, primarily in Orkney, with 21.2% present in Iceland and less than 4% in each of Southwest Norway, Ireland and all other regions in Britain (Table 1).
Table 1. Regional distribution of Iceland Greylag Geese during November 2020 (nc represents no count received or no count undertaken). See Brides et al. 2021 for further details).
Region November Iceland 12,734 Southwest Norway 1,500* Faroe Islands nc Ireland 2,196 North Scotland 64,958 Northeast Scotland 2,250 East Central Scotland 3,192 Southeast Scotland/Northeast England 3,693 Southwest Scotland/Northwest England 657 East England 1,402 Total counted 92,582 Adjusted counts -32,521 Population estimate 60,061
*Count made in January 2021 (see Brides et al. 2021)
Figure 1. Annual census-derived estimates of Iceland Greylag Goose population size, 1960–2020. Five year running mean shown as red line (e.g. mean for 2018 is from population estimates for 2016-2020).
Due to the increasing difficulty in assessing the breeding success of Iceland Greylag Geese on the wintering grounds, no age assessment data was collected during autumn 2020. See Discussion.
The 2020 population estimate (60,061) for the Iceland Greylag Goose is lower than the 2019 estimate and below the average for the previous ten-years (87,804 birds; 2010–2019), as it has been since 2013 when the population estimate notably declined following the most recent peak in 2011. This recent apparent decline in the population is a cause for concern.
The methodology used to estimate the number of Iceland Greylag Geese has remained consistent over time, and thus the population estimate is believed to be robust. However, it remains unclear to what degree undercounting and possible under-estimation in Orkney and Iceland may have affected recent population estimates. Whilst Orkney and Iceland are the two sites which hold the majority of Icelandic birds, more up to date information from the wintering areas is needed, especially in regard to the numbers and distribution of British Greylag Geese which may mix during the winter with birds from the Iceland population.
Large numbers of British Greylag Geese in core wintering areas of the Iceland population, such as in Orkney, Caithness and the Moray Firth. In order to provide an estimate of the number of Iceland birds in areas where British birds also occur, we deduct an estimate of the number of British birds thought to be in the area during the time of the November census. Up to date information on the status of Greylag Geese in Britain, especially south and east of an arbitrary line from Bute east to Aberdeen (although increasingly north of this line too) are largely lacking. Therefore, simply as a precaution, any counts obtained through the IGC from the area south and east of the arbitrary line, are assumed to be British birds and are subtracted from the total count. Given that information on British birds in these areas is now largely out of date, the undertaking of late summer surveys in key areas, similar to those undertaken occasionally on Orkney, would be highly advantageous and would allow a more accurate population estimate to be derived. Furthermore, in order to better understand the current overlap in the distribution of the two populations, marking and tracking of the Icelandic birds would help determine how far south this population is wintering in Britain.
Consideration of hunting pressure on the Iceland population, both in Iceland and Britain, also needs to be taken in to account as an important driver of the observed decline. Possible changes in the timing of the autumn migration from Iceland to Britain has the consequence to allow for more birds to be shot in Iceland prior to departure. During 2019, 42,780 Greylag Geese were reported shot in Iceland, this being similar to the previous ten-year mean (2009–2018: 45,444 birds ± 1,816 SE) (Statistics Iceland 2021). However, since 2008, the average total bag for Greylag Goose in Iceland has been 45,252 birds (±1,517 SE) which is a c.10,000 increase in the number of birds harvested per year compared with prior to 2008. This increase fits with the period of decline observed in the Iceland Greylag Goose population since 2011. To gain a better understanding of the effects of harvesting on the Iceland Greylag Goose population, collaboration with hunting officials in Iceland and the integration of hunting bag data in to analyses of population estimates is required. Furthermore, hunting bag statistics are not routinely collected in Britain and Ireland and it would be advantageous to initiate the annual collection of these data to contribute to a better understand of hunting pressure on wintering Iceland Greylag Geese.
British Greylag Geese on Orkney are being managed to try to reduce impacts on agriculture in the islands. Shooting under this scheme does not overlap with the period when Icelandic birds are present; however, Greylag Goose has recently been placed on general licence GL02/21 in Scotland that allows birds to be controlled to protect crops and livestock throughout the year. There is, therefore, a short period of the close season from the end of January through to the point when Icelandic birds leave Scotland, when there could be increased shooting mortality for the Icelandic population. Increased shooting pressure and the extension to the shooting season could also potentially be causing some British birds to start wintering off Mainland Orkney and moving to the surrounding islets. There is, therefore, the potential for Icelandic birds to be at greater risk of being shot during the winter period if they winter mainly on Mainland Orkney. Currently the proportions of British and Icelandic birds on different islands is unknown.
To gain a better insight into the movements of British birds on and surrounding Mainland Orkney, it would be advantageous to capture and colour-mark British Greylag Geese on Orkney during the summer, to study their winter movements and distribution in relation to the Icelandic birds.
The colour-marking of both Iceland and British Greylag Geese plays an important role in the future monitoring of the Iceland population. By colour-marking birds this will bring about a better understanding of the wintering distribution of Iceland Greylag Geese, provide information on the timing of movements from Iceland and allow updated survival analyses to be undertaken; the last such assessment was undertaken in 2004 (Frederiksen et al. 2004). Up to 35 Iceland Greylag Geese are being fitted with GPS tags in Iceland in the summer of 2021. With a potential lifespan of two years these tags should provide a considerable amount of information on the migration timing, winter distribution and in-winter movements of this population.
Recommendations for the future monitoring of this population were given in Brides et al. 2020. However, as mentioned in previous reports, the monitoring of Iceland Greylag Goose breeding success on the wintering grounds in Britain is becoming increasingly difficult due to the overlap in the wintering ranges of the Iceland and British populations. Due to this, no assessment of breeding success was undertaken during 2020. As part of further discussions surrounding the monitoring of the Iceland population, preferably with the inclusion of contacts in Iceland, consideration should be given to exploring ways in which breeding surveys of the species can be undertaken in Iceland before the autumn migration commences.
Many thanks go to the many IGC counters and Local Organisers who provided the basis of the population estimates. Thanks also go to those who contributed age assessment data.
Brides, K, C. Mitchell & S. N.V. Auhage. 2021. Status and distribution of Icelandic-breeding geese: results of the 2020 international census. Wildfowl & Wetlands Trust Report, Slimbridge.18 pp.
Brides, K, C. Mitchell, A. Sigfússon & S. N.V. Auhage. 2020. Status and distribution of Icelandic-breeding geese: results of the 2019 international census. Wildfowl & Wetlands Trust Report, Slimbridge.19pp.
Frederiksen, M., R.D. Hearn, C. Mitchell, A. Sigfússon, R.L. Swann, R.L. & A.D. Fox. 2004. The dynamics of hunted Icelandic goose populations: a reassessment of the evidence. Journal of Applied Ecology 41: 315–334
Statistics Iceland. 2021. Online database: https://statice.is/. Accessed July 2021.
Previous annual results will be archived here. Annual Icelandic-breeding Goose Census reports can be found on the Reports & newsletter page.
The colour-marking of Iceland Greylag Geese began in earnest in the early 1990s, when Highland Ringing Group (led by Bob Swann), supported by WWT, began to cannon-net birds and mark them with grey neck collars at Loch Eye, near Tain. This provided the first understanding of how Iceland Greylags moved around the wintering grounds. In 1996, WWT and the Icelandic Institute of Natural History began a five year marking programme, capturing around 1,000 birds (moulting adults and goslings) at breeding and moulting sites in Iceland. Other British ringing groups also contributed to the capture and marking at this time, most notably the Grampian Ringing Group. This collective effort resulted in a large dataset of re-encounters of marked birds, and a number of papers were published using this information, including analyses of winter movements (Swann et al. 2005), and survival rates (Frederiksen et al. 2004).
More recently, fewer birds have been marked; but targeted marking of small numbers continues to take place in Ireland by Alan Lauder and several small catches on Islay, north west Scotland and on the breeding grounds in Iceland. Much of this work is focussed on questions about the status of Greylags in certain parts of Scotland and Ireland, where there is increasing overlap in winter range between British Greylag Geese and Icelandic birds, making monitoring more difficult.
Sightings of marked birds are still sought from birdwatchers. If you see a colour marked bird, please submit your sighting to firstname.lastname@example.org.
Frederiksen, M., R.D. Hearn, C. Mitchell, A.Þ. Sigfússon, R.L. Swann & A.D. Fox. 2004. The size and dynamics of Icelandic-breeding goose populations: a reassessment of the evidence. Journal of Applied Ecology 41: 315-334.
Swann, R.L., I.K. Brockway, M. Frederiksen, R.D. Hearn, C. Mitchell & A. Sigfússon. 2005. Within-winter movements and site fidelity of Icelandic Greylag Geese Anser anser. Bird Study 52: 25-36.
Hearn, R.D. & C.R. Mitchell. 2004. Greylag Goose Anser anser (Iceland population) in Britain and Ireland 1960/61 – 1999/2000. Waterbird Review Series, The Wildfowl & Wetlands Trust/Joint Nature Conservation Committee, Slimbridge. Download
Mitchell, C. 2012. Mapping the distribution of feeding Pink-footed and Iceland Greylag Geese in Scotland. Wildfowl & Wetlands Trust / Scottish Natural Heritage Report, Slimbridge. Download
Other relevant material
Hunting in Iceland: The numbers of Greylag Geese hunted in Iceland are available here.