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SECTION 2 Population Viability Analyses ( PVA) and review of populations of geese wintering and breeding in Scotland
2.1 This chapter outlines the current status of Scottish goose populations in terms of population size and trends, including new information from the Population Viability Analyses ( PVA) carried out in 2004-05 on the five main overwintering goose populations found in Scotland. The models for each population took note of the size categories adopted in the African-Eurasian Waterbird Agreement 7 ( AEWA); 10,000, 25,000 and 100,000 birds (see Annex 3.2). Monitoring and research requirements for the next five years are also identified to enable Scotland to respond to a range of population and management issues domestically and to support international efforts. The chapter also considers whether NGMRG policy has met the fundamental objective within the national policy framework to " meet the UK's nature conservation obligations".
Summary of the current understanding of status and viability of each goose population
2.2 The five-year trends of the goose populations that occur in Scotland have been varied. The Greenland white-fronted and Icelandic greylag goose populations show some signs of decline, while the pink-footed goose is increasing. The current population sizes and trends of the main breeding and wintering goose populations occurring in Scotland are summarised at Annexes 3.3 and 3.4.
Naturally - occurring goose species which winter and/or breed in Scotland
Greenland white-fronted goose ( Anser albifrons flavirostris)
2.3 Numbers have increased since the early 1980s to a peak of about 34,000 in the late 1990s, but have since declined to about 26,500 in 2002 with some 17,500 birds in Scotland and 9,000 in the Republic of Ireland. Within the UK, most birds continue to winter in Scotland on Islay. Small numbers occur down the west coast from Caithness southwards to Dumfries and Galloway, with flocks of around 1,000 birds on Tiree and Coll, and at Machrihanish and Rhunahaorine in Kintyre.
Svalbard barnacle goose ( Branta leucopsis)
2.4 This population continues to breed entirely on Svalbard and has increased from a very low level in the 1940s (c. 300 birds) to the 2003-04 estimate of 27,000 birds. There has been no significant change in the location of the Scottish wintering population since 2000. The geese are still found around the Solway Firth, mainly on the Scottish side, principally around Caerlaverock and Mersehead, though increasing numbers are using Calvo, Newton and Skinburness Marshes on the English side. In addition, smaller numbers are still found at a number of east coast localities, especially early on in the season (such as Loch of Strathbeg and Loch Leven). In the early 1990s the population was thought to be stabilising, but it is now increasing again, probably due to the expansion into new breeding habitat on Svalbard.
Greenland barnacle goose ( Branta leucopsis)
2.5 The Greenland barnacle goose population has increased markedly in the last 30-40 years and is now higher than it was in 2000 (40,000 - 45,000 birds). The spring 2003 population estimate was 56,400 individuals. The majority of the wintering population is located on Islay (77% of the Scottish population and 65% of the global population). In addition, there are smaller numbers at other west-coast island locations, ranging from Orkney and the Outer Hebrides to Tiree and Coll. A further 9,000 birds winter in the Republic of Ireland.
Greylag goose ( Anser anser)
2.6 There are three different populations of greylag geese found in Scotland: Icelandic, native and reintroduced. The Icelandic population winters mostly in Scotland while the other two populations are resident year round.
2.7 In 2000 it was believed that the population trend for Icelandic greylag geese was either stable or declining. The population had peaked at c. 100,000 in the early 1990s, and subsequently declined to around 80,000 individuals. The population trend is now believed to be downward, and numbers were estimated in autumn 2002 at 73,000. (Since completion of the analyses the autumn 2003 censuses have become available with a new total of 81,000). Birds winter on Orkney, and on low-lying agricultural ground around the Moray Firth, Grampian, Tayside, Fife, the Lothians and Borders and Dumfries and Galloway, with a few birds also located in northern England.
2.8 Populations of native and reintroduced greylag geese continue to be modest compared to the migratory Icelandic greylag goose population. It is believed that the native greylag population has increased from about 10,000 birds in 2000 to 15,000 birds in 2004. These are found mainly in the Northern and Western Isles, Tiree and Coll and Caithness and Sutherland. There are limited data on the reintroduced greylag population, which are found mainly in southern and central Scotland but estimates suggest a minor decrease from 2,673 in 1989 to 2,340 in 1991.
Pink-footed goose ( Anser brachyrhynchus)
2.9 The Icelandic/Greenlandic population of pink-footed geese has shown a substantial increase in the last 50 years from a population of about 20-30,000 in the early 1950s, stabilising in the 1970s at around 80,000 and then increasing again to the 2000 level of around 230,000. (Since the completion of the analyses, the results of the autumn 2003 censuses have become available with a new total of 281,000). Pink-footed geese continue to breed in the interior of Iceland and in smaller numbers on the east coast of Greenland. In winter, most birds occupy low lying agricultural land from the Moray Firth down through Grampian, Tayside, Fife and into the Lothians and Borders and Dumfries and Galloway. Large numbers also continue to migrate through to Lancashire and Norfolk.
Taiga bean goose ( Anser fabalis fabalis)
2.10 In Scotland, the Taiga bean goose population has been increasing over the last five years with a peak during winter 2003-04 of 235 birds which represents nearly half of the UK wintering population. The population breeds in Scandinavia and NW Russia and winters across West and Central Europe. The only wintering area in Scotland continues to be the Slamannan Plateau in North Lanarkshire. The only other regular site in the UK is the Yare Valley near Norwich where numbers appear to be decreasing. Brent goose ( Branta bernicla hrota)
2.11 The light-bellied Brent goose population from the east Canadian high arctic winters largely on the east coast of Ireland. The population currently (2003-04) totals about 28,000 birds 8. A small number (c. 25 birds) now regularly winters on Loch Ryan near Stranraer, and birds occasionally winter on Loch Indaal on Islay. In addition, brent geese (probably from Svalbard, which winter on Lindisfarne) are regularly seen on passage in the north-east of Scotland.
Introduced geese
Canada goose ( Branta canadensis)
2.12 The Canada goose is an introduced species to the UK, and Scotland is thought to hold about 1,200 birds. This number may be increasing. Most of the UK population breeds and winters in England, though some birds from northern England undergo a moult migration to Scotland (the Beauly Firth) in a manner similar to the ancestral population in the USA. Occasionally, wild birds arrive with wintering Icelandic/Greenlandic goose populations.
Snow goose ( Anser caerulescens)
2.13 The snow goose is an introduced species to the UK with less than 100 recorded in 2000-01. The majority of records are in England with a small self-sustaining population on Mull and Coll, and occasional sightings elsewhere in Scotland, some of which are wild birds which arrive with wintering Greenland goose populations.
Bar-headed goose ( Anser indicus)
2.14 The bar-headed goose is an introduced species from Asia with less than 100 recorded across the UK in 2000-01. The vast majority of records are in England with occasional sightings in Scotland, notably in Dumfries and Galloway.
Hybrid geese
2.15 A number of hybrid geese which have appeared largely as a result of interbreeding of introduced/reintroduced populations, or of escapes from collections, are now living in a wild state in the UK. The most abundant is a Canada/greylag goose hybrid. In the 2000 survey 9 of naturalised geese in Britain, 301 hybrid geese were counted; small numbers are seen in central and southern Scotland. The longer-term implications and impact of populations of introduced species will require to be considered in more detail by the Scottish Executive, SNH and others in the context of wider policy on potentially invasive non-native species.
Main findings of the new Population Viability Analyses ( PVAs)
2.16 As part of the review process, SNH contracted the Institute of Zoology, London and the Wildfowl and Wetlands Trust to update the PVA work carried out for the National Goose Forum 10 in 1995-1999 for the five main populations of geese in Scotland: Greenland white-fronted goose, Svalbard barnacle goose, Greenland barnacle goose, Icelandic greylag goose and pink-footed goose. The analyses cover data up to 2002 (greylag and pink-foot) and 2003 for the other three species. The PVAs provide the NGMRG with the best possible predictions of future population trends and the best assessment of the impact of any such changes. Further information and a guide to understanding the new goose PVAs, along with an overview of the information papers on each of the PVAs is provided at Annex 3.
Greenland white-fronted goose
2.17 The new analyses indicate that following a period of steady growth through to the mid 1990s the overall Scottish population had stabilised at c. 21,000 but has now declined to a current level of 17,500. These changes appear to have been driven by a reduction in the proportion of birds that bred successfully, rather than any changes in the mean clutch size, brood size or adult survival rate.
2.18 The baseline model predicts an equilibrium Scottish population size of around 20,000, with a low risk of decline below 10,000 within 25 years, assuming the conditions experienced over the last 20 years are maintained. The population appears to be currently regulated by density-dependent processes and future projections are particularly sensitive to any change in adult survival.
2.19 Continued expansion of the recently-established Greenland breeding population of Canada geese, and subsequent competition for territories with Greenland white-fronts may severely reduce the latter's overall productivity and lead to a high risk of significant population decline.
Svalbard barnacle goose
2.20 The new analyses indicate that the current level of 27,000 Svalbard barnacle geese wintering on the Solway is continuing to rise, in contrast to the situation some 50 years ago. There is currently no evidence to suggest the population has reached the carrying capacity of either the summer or winter range. There is however evidence that reproductive output has declined with increasing population size.
2.21 If breeding is being regulated by population density, then further increases in population size may be relatively modest compared to those seen over the previous 15-20 years. This assumes that the current breeding range in Svalbard will be maintained: if new breeding colonies continue to be established then the population may continue to grow.
2.22 The most sensitive factor, in terms of its effect on population change, is adult survival. Under conditions of density dependence, an additional loss of as few as 350 individuals annually produces a median equilibrium population at its current size of 27,000. The likelihood of long-term population decline increases markedly if additional annual losses exceed 1000 or more.
2.23 The aggregation of this population into one breeding area and one principal wintering area makes this population more vulnerable than any other to chance catastrophic events, such as adverse conditions on the breeding or wintering grounds, disease or adverse conditions during migration.
Greenland barnacle goose
2.24 The new PVA findings indicate that the Greenland barnacle goose population (56,400 globally with 47,300 in Scotland) appears reasonably secure in the long term. Under current conditions the population is predicted to continue to grow, though rates of growth may vary between different wintering locations.
2.25 There is some evidence that density dependent mechanisms may be operating in the Islay sub-population. If so, then numbers on Islay are predicted to remain near the 2003 level of approximately 35,000. The greater population growth seen on Islay compared to some other sub-populations appears to have been a result of higher productivity amongst Islay birds, rather than net immigration to Islay of birds previously wintering in other locations.
2.26 Greenland barnacle geese are currently legal quarry in Iceland and small numbers are shot under licence in Scotland. If the numbers shot each year remain at current levels the predicted risk of population decline below 10,000 in 25 years is less than 0.3%. If density dependence is operating, the additional removal in Scotland of as few as 500 individuals annually may be sufficient to reduce the median equilibrium population on Islay to less than 30,000, increasing the risk of decline below 10,000 within 25 years to 2.5%.
2.27 The population does not appear to be particularly sensitive to catastrophic mortality events, requiring frequent, moderate to large losses before the risk of population decline below 10,000 becomes significant.
Icelandic Greylag Goose
2.28 The autumn counts have described a sustained period of population growth in the UK wintering population peaking at around 100,000 birds in the early 1990s, followed by a decline to about 73,000 in 2002. There is currently a great deal of uncertainty in the 2005 PVA estimates, with suggestions that these counts underestimate the full size of the population, that there are problems with estimating the proportions of juvenile birds, and that it is getting increasingly difficult to distinguish between Icelandic greylags and the resident native and reintroduced greylag populations.
2.29 If current conditions are maintained the best-fit model predicts that the population will decline by approximately 3.5% per year, with a 58% probability that the population will fall below 25,000 within 25 years. There is currently no compelling evidence for the presence of density dependent regulation of population change.
2.30 Whilst this analysis is most sensitive to adult survival, reduction of either juvenile survival or productivity also leads to a higher risk of significant population decline. The underlying demographic parameters indicate that this population is currently under hunting stress and that the current level of hunting in both Iceland (c.35,000) and Scotland (15,000 -25,000) combined is unsustainable over the medium term.
Pink-footed goose
2.31 The 2005 PVA findings indicate that the current population of pink-footed geese, of about 230,000 individuals, is healthy and the long-term likelihood of decline under current conditions is very small. The risk from any catastrophic events is also very low, except in the most extreme conditions modelled.
2.32 If the current conditions and levels of shooting (c.13,000 in Iceland and c.25,000 in the UK) are maintained, the predicted median equilibrium pink-footed goose population size is approximately 220,000, and there is just a 2% probability the population will decline below 50,000 within 25 years.
2.33 These analyses are most sensitive to changes in adult survival. However, even this needs to be reduced quite significantly in order to obtain a 25% probability that the population will fall below 50,000. To observe this fall, large reductions to the current mean adult survival, juvenile survival or productivity (8%, 44% or 46% respectively) are required.
2.34 The current level of shooting appears to be sustainable. A reduction in the number shot per year of 5,000 reduces the predicted probability of population decline below 50,000 within 25 years from 2% to 0.4%. However, if an additional 5,000 geese are shot per year the likelihood of decline below 50,000 in 25 years increases to 11% and the average population size after 25 years falls to 180,000.
Management recommendations for each population
2.35 These recommendations replace NGF Recommendations 1 to 10 based on the new population analyses, and associated assessment of monitoring requirements necessary to support future PVA work.
Naturally-occurring goose species which winter and/or breed in Scotland
Greenland white-fronted goose
2.36 The conservation status of the Greenland white-fronted goose population has improved markedly over the past few decades but recent evidence of a substantial reversal in the population trend raises some real concerns. Given the potential vulnerability of this population to quite small changes in additional mortality the population should retain its current protected status.
2.37 Greenland white-fronted geese appear to be currently free from substantive threat on their wintering grounds in Scotland. The key constraints appear to operate on their breeding grounds in West Greenland and while staging in Iceland. Research should be encouraged in Greenland into the reasons why the proportion of adults breeding has declined and the potential role of Canada geese in this.
2.38 Current monitoring of overall numbers and distribution appears to be adequate and should be continued. The key shortfalls are in the collection of breeding productivity data at a wider range of wintering sites (away from Islay). Further collection and analysis of body condition data on Islay and elsewhere is also seen as potentially useful.
Recommendation 2: Given the vulnerability of the Greenland white-fronted goose population to additional mortality, there should be a presumption against a change in the protected status of the population and against the issue of licences for shooting to prevent serious agricultural damage. There appear to be no scientific reasons for changing the current management regimes across Scotland.
Svalbard barnacle goose
2.39 The Svalbard barnacle goose population has continued to rise and seems likely to continue to do so, albeit at reduced rates, as productivity has declined with increasing population size. Future trends look more likely to be dependent upon developments or changes to the breeding grounds.
2.40 The PVA suggests that on average, an increased mortality of 350 birds per annum would produce a stable population at its current size of 27,000. However, a different element of the analysis shows that the confidence limits of the modelling are such that there is a greater than 70% chance that any mortality above current natural levels would result in a decline to below 25,000 birds over the next 25 years. A decline below 25,000 would move the population back into a higher threat category under the AEWA classification. The outcomes of the ongoing FRAGILE project 11 may inform future management priorities for this population.
2.41 Current monitoring effort is very good and should be continued, albeit count frequency could potentially be reduced.
Recommendation 3: The new PVA modelling has shown the vulnerability of the Svalbard barnacle goose population to additional mortality. Due to this there should be a presumption against a change in the protected status of the population. There is no scientific reason to alter the current management regime for Svalbard barnacle geese in Scotland.
Greenland barnacle goose
2.42 Overall the Greenland barnacle goose population is currently increasing in Scotland. However, population trends vary in different areas of the Scottish wintering range. Licensed shooting to prevent serious damage to crops is currently undertaken on Islay to reinforce scaring as an aid to overall management. At the current population level the PVA analyses suggest that if the current level of shooting is maintained there is not a significant risk of population decline. If additional shooting of 500 birds were to occur, the PVA predicted that this would lead to population decline, with a greater than 70% chance that the population would fall below 25,000 in the next 25 years. The PVA also suggests that if density dependence is operating as modelled, the Islay population is predicted to remain near its current size.
Recommendation 4: Current levels of licensed shooting of Greenland barnacle geese on Islay (c. 500 birds per annum) do not appear to be having a negative effect on population size. There appear to be no scientific reasons for changing the current management regimes across Scotland.
Greylag goose
Icelandic greylag goose:
2.43 The Icelandic greylag goose population has altered over the last 10-15 years with a pronounced reversal of the previous upward trend. Substantial changes in winter distribution have also occurred. Evidence now points to current shooting levels being unsustainable with a high probability of substantial further decline in numbers if these pressures do not change. It is imperative that continued and improved monitoring of the population size and of shooting mortality occurs, and that monitoring problems identified in the PVA and other studies are addressed.
2.44 In the close season, especially during late winter and early spring, licences are currently issued in some areas to prevent serious damage to crops. This requires to be monitored and assessed very carefully due to both the precarious nature of the goose population and the known adverse ecological impact of spring shooting. Measures are also needed to encourage a voluntary reduction in hunting take during the open season. The PVA study suggests that a relatively small reduction in shooting pressure may be sufficient to arrest the current decline in population size.
2.45 The population is counted twice annually (October and November). Unlike the case with pinkfeet, concern has recently been expressed about the accuracy of the results obtained both in terms of absolute numbers and age structure (Frederiksen et al)12. In addition, some native and reintroduced greylags are also included in the October and November censuses. These issues need to be addressed and Hearn 13 has recently produced a set of proposals to do this. Given the degree of hunting stress detected in this population it is important that a better measure is obtained of changes in hunting pressure; this issue is addressed at paragraph 2.57 of this report.
Native greylag goose:
2.46 The numbers and range of native greylag geese are currently undergoing rapid change. Regular counts are conducted in some areas, e.g. Coll and Tiree and the Uists, but many other areas are counted only infrequently. A more regular, Scotland-wide perspective is currently desirable. The last full late summer census was conducted in 1997 and the next is planned for 2006. These censuses need to be carried out more frequently using a robust survey methodology, and they can then be used to assess the proportion of the wintering population in these areas which is resident in Scotland, as opposed to Icelandic migrants.
Reintroduced greylag goose:
2.47 Current Wetland Bird Survey ( WeBS) coverage of reintroduced greylags is incomplete and dedicated national censuses have been infrequent. As numbers increase it would be desirable to obtain better information on numbers and distribution in early autumn, not least to assess the proportion of the wintering population in these areas which is resident in Scotland, as opposed to Icelandic migrants.
Recommendation 5: Measures should be taken in Scotland to adapt the shooting take of Icelandic greylag geese to sustainable levels. These measures should address open season bags and closed season licences. International collaboration is needed with development of adequate tools for the regular assessment of population size, productivity and hunting bags.
Pink-footed goose
2.48 The pink-footed goose population has continued to increase in recent years and the current level of shooting appears to be sustainable. The PVA suggests that a modest increase in shooting pressure in the UK and/or Iceland could lead to a long-term decline. No management changes related to this population are required at present, although adequate monitoring of the shooting bag is needed to maintain robust population analyses. This issue is addressed at paragraph 2.57 of this report.
2.49 In the close season, especially during late winter and early spring, licences are currently issued, where appropriate, to prevent serious damage to crops. There appears to be no good scientific reason to vary this practice. It is imperative that good monitoring of the population continues and adequate assessment of shooting mortality occurs. At present, the autumn roost counts carried out in October and November provide an acceptably accurate assessment of the population size.
Recommendation 6: There is no scientific reason to vary current management arrangements for pink-footed geese in Scotland.
Taiga bean goose
2.50 In Scotland, the population of bean geese on the Slamannan Plateau continues to rise slowly, to the point where it is about half of the population in the UK, and the current monitoring effort is excellent. SNH are currently investigating the merits of a Natural Care scheme to provide positive management benefits for bean geese, given that there are concerns about changing land use in this area.
Recommendation 7: No alteration to the protected status for Taiga bean geese is required.
Brent goose
2.51 The small Scottish wintering flock appears to be becoming a regular feature on Loch Ryan. Current monitoring effort is sufficient; no special measures are required for this population.
Recommendation 8: No alteration to the protective regime for brent geese is required.
Introduced Geese
Canada goose
2.52 Data for numbers of breeding Canada geese in Scotland are limited and not sufficient to produce a robust population estimate. Currently, the Scottish breeding population is inferred from numbers present in the winter and it may be that this is a suitable method for approximating the total. It may, however, be prudent to undertake a dedicated survey in the breeding season with the aim of testing the accuracy of the inferred count. No management changes related to this species are required.
Recommendation 9: Canada geese may continue to be hunted during the open season, or shot under licence where there is serious damage to agriculture.
Other introduced goose species and hybrids
2.53 While other species of geese are not currently abundant or troublesome in Scotland it would be wise to maintain a basic level of surveillance of snow goose, bar-headed goose and other introduced and hybrid geese. This is adequately achieved through existing Wetland Bird Survey ( WeBS) counts coupled with periodic specific surveys, by volunteers, of introduced goose populations.
Future monitoring and research requirements
2.54 These recommendations replace NGF Recommendations 29-32 based on the new assessments of research and monitoring requirements by GSAG, and associated assessment of the monitoring requirements necessary to support future PVA work.
2.55 To enable future national goose policy to continue to support the principle of meeting the UK's nature conservation obligations, further monitoring and research is required to enable detailed assessments to be made of Scottish goose populations in the future. These assessments will require close co-operation with Defra regarding the rest of the UK, and with the other countries on the goose flyways, to ensure impacts on geese outwith the UK are suitably assessed.
2.56 GSAG has reviewed the adequacy of current monitoring effort for geese in Scotland, and has identified the monitoring and research activities which need to be improved over the next five years (Annexes 3.3 - 3.6). In large part this assessment is designed to provide better datasets to inform the next five-year review, particularly in respect of goose flocks outwith Islay. This has been converted into a draft prioritised list of research, survey and monitoring work for the next five years to improve knowledge on goose species in Scotland and improve information required for PVAs (Annex 3.6).
Recommendation 10: To enable improved monitoring of the conservation status of the key goose populations, a detailed five year research and monitoring programme should be developed during 2005, and further population viability analyses should be commissioned in 2009-10 to inform consideration of national goose policy at the next five year review.
2.57 Reliable annual information on the shooting bags of pink-footed and greylag geese is required in order to conduct effective PVAs, understand population changes, and assist in informing policy responses to those changes. In this context it is recognised that current Scottish data on hunting mortality are inadequate and compare poorly with the extent and detail of information available in other range states, most notably Iceland.
2.58 For this reason, NGF recommendations 29, 30 and 31 previously highlighted the need to establish the numbers of quarry species shot annually and the need to consider instituting a compulsory bag return for visiting goose shooters. Pilot studies 14 were undertaken in
2001-03 to assess the feasibility of taking forward those recommendations, for example by means of a survey of shotgun certificate holders. These studies concluded that it is not meaningful to obtain goose hunting bag statistics from voluntary surveys within Scotland alone (as many goose shooters originate from elsewhere in the UK), that voluntary surveys introduce a number of biases into the data (although mandatory schemes are not without biases) and that there is no reliable 'voluntary organisation route' for surveying shooters who are resident outwith the UK who come to shoot geese in Scotland.
2.59 Achievement of the original objective - that is, ensuring the availability of robust data on total numbers of geese taken during the open season - remains a high priority, and one which is shared at UK level by Defra. Further progress in this area will be significantly assisted by an immediate research project examining the mechanisms employed in other countries which already have robust methods (both voluntary and mandatory) of collecting bag statistics. This research should include an assessment of administrative methods, financial costs, and impacts upon both the shooting community and the species concerned.
Recommendation 11: Further work requires to be done on developing robust mechanisms for obtaining reliable hunting bag statistics. This work should be co-ordinated with efforts being undertaken at a UK level.
The international context
2.60 There have been a number of attempts to address international goose management issues and maintain the conservation status of migratory goose populations. In 2000, the NGF report identified that draft flyway plans for Greenland white-fronted geese and Svalbard barnacle geese were in the process of being developed. The plans have made very limited progress since then, and although NGF Recommendation 12 indicated that the national policy framework should be implemented in co-operation with other countries with relevant goose interests, there has been limited progress on this front.
2.61 Goose range states such as Iceland, Greenland, Norway, the Republic of Ireland and the UK already participate in, or are parties to, a number of fora, treaties and conventions. There are already good examples of efforts being made by other range states to ascertain the risks to certain goose species. Given that the new analyses indicate that there are a number of issues outwith the UK which could potentially affect the population status of certain overwintering goose species, further work is now required to develop and enhance links between countries to address these issues through closer collaboration between scientists and administrations. This will also support the work of range states in conserving biological diversity and securing the sustainable use of natural resources in line with the Convention on Biological Diversity ( CBD), 1992.
Recommendation 12: Stronger links should be developed with other goose range States in order to explore and facilitate multilateral agreements relating to specific issues, including international research and monitoring and information-sharing. In particular, to tackle issues relating to the conservation status of the Greenland white-fronted goose population.
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