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) huntable during the open season
Flyway population size (CSR 7; Wetlands International 2015) 93,750 individuals GB estimate (Frost et al. 2019) 91,000 individuals UK trend (Frost et al. 2020) 25-year trend (1992/93-2017/18) = 6% decrease
10-year trend (2007/08-2017/18) = 1% increase
Table 1. 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 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.M., N.A. Calbrade, G.A. Birtles, H.J. Mellan, C. Hall, A.E. Robinson,S.R. Wotton, D.E. Balmer & G.E. Austin. 2020. Waterbirds in the UK 2018/19: The Wetland Bird Survey. BTO, RSPB and JNCC, in association with WWT. British Trust for Ornithology, Thetford.
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.
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. 2020. 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 2020. 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 2019/20 [October 2020]
The 60th consecutive Icelandic-breeding Goose Census (IGC)
took place during autumn and winter 2019, providing information on the abundance and distribution of Iceland Greylag Geese. A full account of the census can be found in Brides et al. (2020).
A network of volunteer observers and professional conservation staff conducted counts over the weekend of 23/24 November.
Coverage was excellent across the range, with 166 sites checked (compared with 150 in 2018). 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 Icelandic migrants occurs in late October and early November and they remain there throughout the winter (A Follestad. pers. comm.).
The total count was 101,235 Greylag Geese (Table 1). Following adjustments for the presence of British/Irish Greylag Geese, which is significant in some areas, a population estimate of 73,355 was derived. This represented an increase of 25.6% compared to 2018 (Figure 1), when a population of 58,426 was estimated.
By November, just under three-quarters of the population (72.5%) were found in North Scotland, primarily on Orkney, with 22.5% present in Iceland, 3.0% in Ireland, 1.6% in Northeast Scotland and 0.1% in Southwest Scotland/Northwest England (Table 1). A small percentage (0.4%) of the population was also located in Norway.
Table 1. Regional distribution of Iceland Greylag Geese during November 2019.
Region November Iceland 16,500 Southwest Norway 267* Faroe Islands 689 Ireland 3,341 North Scotland 72,913 Northeast Scotland 1,251 East Central Scotland 1,874 Southeast Scotland/Northeast England 3,574 Southwest Scotland/Northwest England 593 West England 2 East England 231 Total counted 101,235 Adjusted counts -27,880 Population estimate 73,355
Figure 1. Annual census-derived estimates of Iceland Greylag Goose population size, 1960–2019. Five year running mean shown as red line (e.g. mean for 2017 is from population estimates for 2015-2019).
During mid-November, 1,200 Greylag Geese from six flocks were aged at various locations in Caithness, Scotland. This represented 1.6% of the 2019 population estimate. The brood size of 12 families was also determined during this period. These are very small sample sizes due to the uncertainly in knowing which population the geese being aged belong to. In almost all areas in north Scotland birds from both the British-breeding and Iceland-breeding populations occur together.
The percentage of young found amongst flocks (20.1%) was lower than the previous year (22.6% in 2018), and lower than the recent ten-year mean (mean 2009–2018: 21.7% ± 0.40 SE). The mean brood size of 2.17 goslings per successful pair was lower than that of the previous ten-year mean (mean 2009–2018: 2.23 ± 0.08 SE).Figure 2. The percentage of young (blue columns) and mean brood size (red circles) of Iceland Greylag Geese, 1960–2019.
The population estimate of 73,355 Iceland Greylag Geese was 25.6% higher than the 2018 estimate (58,426), suggesting undercounts during 2017 (60,962 birds) and 2018 (58,426); however, it is worth noting that the population estimate in 2019 remains below the ten-year average of 92,851 birds (2009–2018). While it remains uncertain the degree to which undercounting and under-estimation in Orkney and Iceland (the two sites holding the majority of birds) may have affected the 2017 and 2018 population estimates, given that the 2019 population estimate remains below the ten-year average, the trajectory of the Iceland Greylag Goose population needs carefully monitoring to identify any real time declines to this population.
Orkney continues to hold the largest proportion of the Iceland Greylag Goose population. As the islands also hold wintering geese from the British population, a good understanding is required of the number of British birds present in order to determine an estimate for the number of Icelandic geese. To estimate this for 2019, we used the total count from the August 2019 post-breeding census of Greylags in Orkney (22,956 birds; (Plowman J. In prep.) from which we deducted an estimate of the number of British birds shot in Orkney between August and November 2019 (5,000 birds, J. Plowman pers. comm.). This resulted in an estimate of 18,000 British birds, which was then deducted from the overall Orkney IGC total to estimate the number of Iceland Greylag Geese present in November 2019.
Large numbers of British Greylag Geese in core wintering areas for the Iceland population, such as Orkney and the Moray Firth, means that assessing the abundance of the Iceland population during the non-breeding season remains very difficult. 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) is 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 subtracted from the total count. However, as recently as winter 2019/20, Iceland Greylag Geese have been sighted / GPS tracked as far south as the Central Belt of Scotland (A. Sigfusson pers. comm.) showing some overlap in the wintering population south of the arbitrary line as described above, which means there is a possibility that some Iceland Greylag Geese could have been missed from the overall Iceland population total. The overall total was also adjusted to take in to account resident birds in Ireland and the Faroe Islands too.
The results from summer counts (carried out in 2016, C.Mitchell pers. obs.) suggest that the majority of birds found in Caithness in winter are from the Iceland population; therefore, annual breeding success of Iceland Greylag Geese is determined by using counts from wintering flocks there. In 2019, the percentage of young found amongst flocks was 20.1% which was lower than the recent ten-year mean (mean 2009–2018: 21.7% ± 0.40 SE). The monitoring of annual breeding success of this species remains difficult because of the overlap in the main wintering area (Orkney and around the Moray Firth) of both Greylag Goose populations.
The harvesting of Greylag Geese in Iceland has fluctuated between c.38,000–60,000 birds annually between 2008 and 2019 (at the time of writing, data for 2019 are preliminary) (Figure 3; Statistics Iceland 2020). Since the start of hunting bag reporting in Iceland, the average total bag for Greylag Goose has been 40,295 birds (± 1.391 SE). Whilst it is currently unknown to what degree the effect of harvesting in Iceland may have on the overall population total, knowledge of how harvesting on the wintering grounds affects the population is also required; however, hunting bag statistics are not collected in Britain and Ireland. It would therefore be advantageous to initiate the annual collection of hunting bag data in Britain to contribute to a better understanding of the demography of the Iceland Greylag Goose population.
Figure 3. The annual number of harvested Greylag Geese in Iceland, 1995–2019. Data for 2019 (non-filled circle) are preliminary. No data are available for 2003. (Statistics Iceland 2020).
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. 2020. Status and distribution of Icelandic-breeding geese: results of the 2019 international census. Wildfowl & Wetlands Trust Report, Slimbridge.19 pp. Download
Plowman, J. In prep. Survey of Resident Greylag Goose in Orkney, September 2019. NatureScot report.
Statistics Iceland. 2020. Online database: https://statice.is/ – accessed 10 August 2020.
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.