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.
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Global status (IUCN Red List of Threatened Species)
African-Eurasian Waterbird Agreement (AEWA)
European status (European Red List of Birds)
The Birds Directive (European Commission)
UK status (Birds of Conservation Concern)
UK quarry species (Wildlife & Countryside Act 1981)
Least Concern (Europe and EU27)
Annex II (Part A)
huntable during the open season
Flyway population size (CSR 7; Wetlands International 2015)
GB estimate (Frost et al. 2019)
Irish estimate (Crowe & Holt 2013)
GB trend (SUKB 2017)
Breeding success (GSMP survey)
Long-term trend (1989/90 – 2014/15): 10% decrease
Ten-year trend (2004/05 – 2014/15): 9% increase
Proportion of young generally fluctuates between 10% and 25%
Annual estimates of the population size, percentage of young (%) and mean brood size (young per successful pair) of Iceland Greylag Goose, 2003-2018. Data are collected through the Icelandic-breeding Goose Census.
Autumn/winter Estimate of population size Percentage of young (%) Mean brood size 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
Crowe, O. & C. Holt. 2013. Estimates of waterbird numbers wintering in Ireland, 2006/07-2010/11. Irish Birds 9: 545-552.
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.
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 2018/19 [August 2019]
The 59th consecutive Icelandic-breeding Goose Census (IGC) took place during autumn and winter 2018, providing information on the abundance and distribution of Iceland Greylag Geese. A full account of the census can be found in Brides et al (2019).
Counts were conducted by a network of volunteer observers and professional conservation staff over the weekends of 10/11 and 24/25 November: two survey periods were set in November 2019 due to the need to alter the originally planned date of 17/18 November as a result of it conflicting with a conference many IGC counters were attending.
Coverage in Britain was good, with 150 sites checked (compared with 106 in 2017). Outside of Britain, counts were made at several sites in Iceland, Faroes, Ireland and Southwest Norway. Counts in Norway took place in January rather than November, but the total from these counts was used as an estimated count for the November period since guidance from counters in Norway suggests that the winter influx of Iceland migrants occurs in late October and early November and they remain there throughout the winter (A Follestad pers. comm.).
The total count was 92,509 Greylag Geese (Table 1). Following adjustments for the presence of British/Irish Greylag Geese, which is significant in some areas, a population estimate of 58,426 was derived. This represented a decrease of 4.2% compared to 2017 (Figure 1), when a population size of 60,962 individuals was estimated.
Table 1. Regional distribution of Iceland Greylag Geese during November 2018.
Region November Iceland 10,583 Southwest Norway 250* Faroe Islands 1,000 Ireland 3,008 North Scotland 68,040 Northeast Scotland 2,590 East Central Scotland 2,062 Southeast Scotland/Northeast England 4,345 Southwest Scotland/Northwest England 371 East England 260 Total counted 92,509 Adjusted counts -34,083 Population estimate 58,426
*Count made in January 2019 (see Brides et al. 2019)
Figure 1. Annual census-derived estimates of Iceland Greylag Goose population size, 1960-2018. Five year running mean shown as red line (e.g. mean for 2015 is from population estimates for 2013–2017).
During mid-November, 1,378 Greylag Geese from 17 flocks were aged at various locations in Caithness, Scotland. This represented 2.4% of the 2018 population estimate. The brood size of 24 families was also determined during this period.
The percentage of young found amongst flocks (22.6%) was higher than the previous year (19.9% in 2017) (Figure 2) and higher than the recent ten-year mean (2008–2017: 21.9% ± 0.51 SE). The mean brood size of 2.08 goslings per successful pair was lower than that of the recent ten-year mean (2008–2017: 2.25 ± 0.08 SE).
Figure 2. The percentage of young (blue columns) and mean brood size (red circles) of Iceland Greylag Geese, 1960–2018.
The population estimate of 58,426 Iceland Greylag Geese, although lower is not too dissimilar to that in 2017. Suggestions of a recent population decline have been previously reported (see Mitchell & Brides 2017) and it is noteworthy that the population estimate remains well below the ten-year average of 96,838 birds (2008–2017). However, it is uncertain to what degree undercounting affects the 2017 and 2018 population estimates.
Orkney continues to hold the largest proportion of the Iceland Greylag Goose population; however, as geese from both the Icelandic and British populations are present at the time of the census, estimating the number of Icelandic birds also requires an understanding of the number of British birds present.
To do this, we used the most recent post-breeding census of British Greylags in Orkney, undertaken in August 2016 (21,000 birds; see Mitchell & Brides 2017), and adjusted it using an estimate of the number of British birds shot in Orkney between September and November 2018 (2,500 birds). Therefore, in total, 18,500 birds were deducted from the overall Orkney total to give the best possible estimate of the number of Iceland Greylag Geese. This rather crude method would benefit greatly from annual monitoring of the size of the post-breeding British population in Orkney alongside annual estimates of the number of birds shot there, both during the period when both populations are present and when only the British birds are present.
As information on the number of summering British Greylag Geese on Shetland is limited, it is difficult to provide an estimate on the number of wintering Iceland Greylag Geese in Shetland at the time of the census. Therefore, as a precautionary measure, the total number of birds (3,813) was deducted from the overall total. Likewise, information on the status of birds in the Faroes is limited and, as a result, the total number of birds (1,000) was deducted from the overall total. The ringing of summering birds is due to start in the Faroes from 2019 onwards (Jóhannis Danielsen pers. comm.) and will hopefully provide useful information on the winter movements of summering Greylag Geese in the country.
As previously reported, large numbers of British Greylag Geese in core wintering areas for the Iceland populations, such as Orkney and the Moray Firth, mean that assessing the abundance of the Icelandic geese remains very difficult. Up to date information on the status of wintering Greylags south and east of an arbitrary line from Bute east to Aberdeen is largely lacking and, therefore simply as a precaution, any counts obtained through the IGC from this area are subtracted from the total count (as it is assumed that the majority of birds counted are British). However, as recently as winter 2017/18, sightings of colour-marked Iceland Greylag Geese were sighted as far south as Northumberland (B. Swann pers. comm.) showing that some Icelandic birds still winter south of this arbitrary line.
The monitoring of annual breeding success for the Iceland Greylag in Britain is also becoming more difficult because of the overlap in the main wintering areas with British Greylag Geese and it is impossible to separate birds from each population in the field. However, the results from summer counts (carried out in 2016), suggest that the majority of birds found in Caithness in winter are from Iceland (C. Mitchell pers. obs.) and it is in this county only that age counts were undertaken in 2018. However, difficulty was experienced in finding good numbers of geese for ageing in Caithness in November 2018 which led to a very low sample size.
Given the increased difficulty in ageing Iceland Greylag Geese on the wintering grounds and with the discontinuation of the annual wing survey of harvested birds in Iceland, which provided additional information about breeding success, it would be advantageous to explore options for sampling the geese in Iceland prior to migration in order to assess the breeding success of this population. However, this does pose problems since temporal changes in surveillance from November (wintering area) to August/September (in Iceland) will make the comparison of annual results difficult and so a period of overlap whereby both methods are used should be implemented.
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. 2019. Status and distribution of Icelandic-breeding geese: results of the 2018 international census. Wildfowl & Wetlands Trust Report, Slimbridge. 18pp. Download.
Mitchell, C & K. Brides. 2017. Status and distribution of Icelandic-breeding geese: results of the 2016 international census. Wildfowl & Wetlands Trust Report, Slimbridge. 19pp. Download.
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 email@example.com.
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.
Icelandic-breeding Goose Census reports: See the Reports & newsletter page
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.