107 Changes in numbers of staging and wintering geese in Sweden: 1977/78–2019/20 LEIF NILSSON1,* & HAKON KAMPE-PERSSON2 1Department of Biology, Biodiversity, University of Lund, Ecology Building, SE-223 62 Lund, Sweden. 2Pulma i, Gl das pagasts, Jelgavas novads, LV-3040 N kotne, Latvia. *Correspondence author. E-mail: [email protected] Abstract Regular goose counts made throughout Sweden since 1977/78 show that the total numbers staging and wintering in the country have increased markedly over the decades. October totals were of 51,000 geese in 1977, rising to c. 600,000 in 2018, during which time January totals also increased from 31,000 to 252,000 birds. The greatest change recorded was for the Greylag Goose Anser anser, numbers of which rose from 20,000 to > 250,000 individuals over a 35-year period. Changes in migration and wintering habits have also been recorded, with mid-winter (January) Greylag Goose numbers now amounting to 20–33% of the September totals in recent years, illustrating increases in the proportion of the population now wintering in the country. Moreover, large numbers of Barnacle Geese Branta leucopsis have started to stage and over-winter in Sweden, and are now becoming the commonest species, with 365,000 recorded in autumn 2019. Key words: autumn, goose counts, migration patterns, population increase, winter. During recent decades, most Northwest which was formerly widespread across European goose populations have increased the Scandinavian mountain chain but is markedly (Madsen et al. 1999; Fox et al. now reduced to very few breeding pairs, 2010; Fox & Madsen 2017; Fox & Leafloor mainly in Norway, with a re-introduced 2018), with some reaching levels where population occurring in Sweden (Andersson they have come into conflict with & Holmqvist 2010; Fox & Leafloor agriculture when feeding on crops causes 2018). The Taiga Bean Goose Anser fabalis economic losses for farmers (Fox et al. fabalis also has declined in recent years. 2017). In contrast to the majority of goose International Single Species Action Plans species, however, a few of the European (ISSAPs) developed for the conservation populations have decreased over the same both of the Lesser White-fronted Goose period. This is most apparent for the (Jones et al. 2008) and the Taiga Bean Lesser White-fronted Goose Anser erythropus, Goose (Marjakangas et al. 2015; cf. for © Wildfowl & Wetlands Trust Wildfowl (2020) 70: 107–126 108 Numbers of geese staging and wintering in Sweden Swedish data Mathiasson 1963; Nilsson & Since the IWC programme was founded Persson 1984; Nilsson 2013), have been during the 1960s, there have been marked adopted by the African-Eurasian Waterbird changes in the distribution patterns of Agreement (AEWA) under the auspices of different species, which largely seem to be the Convention on Migratory Species. related to climate change with milder In response to decreasing populations of winters enabling the birds to remain in more Taiga Bean Geese and Lesser White-fronted northerly parts of their wintering range. For Geese, the Nordic Council for Wildlife several Anatidae species, this pattern has Research (NKV) established a Goose been established at the international scale Working Group for the region. The main (Lehikoinen et al. 2013; Pavon-Jordan et al. aim of the group was to study the two 2015; Ramo et al. 2015; Nilsson & Kampe- decreasing taxa in the Nordic countries but, Persson 2018; Nuijten et al. 2020) but also following reports of mass mortality among within Sweden (Nilsson & Haas 2016). In Greylag Geese Anser anser wintering in other species, changes in migratory patterns southwest Spain (e.g. in drought conditions; have occurred where habitat management Nilsson & Persson 1996), the Greylag has affected food resources for the geese, Goose was also included in the study e.g. the reduction in cattle grazing in the (Nilsson & Fog 1984). One important Baltic States which consequently reduced task for the working group was to start feeding areas available to Barnacle Geese regular national censuses of staging and Branta leucopsis in this part of the flyway wintering geese; thus, regular goose counts (Eichhorn et al. 2009). commenced in 1977/78. During the first In the present paper, we use the Swedish years of the goose counts, the primary goose counts to describe how the numbers objective was to cover all sites for focal of geese staging and wintering in Sweden species, e.g. the Bean Goose in Sweden have changed since the late 1970s. We also (Nilsson & Persson 1984), but all species aim to evaluate the importance of Sweden were counted at the sites visited. With the as a staging and wintering area for its most initiation of the Greylag Goose studies in abundant goose species – the Bean Goose, 1984, a special September count was added Greylag Goose, White-fronted Goose to cover this species more effectively, Anser albifrons, Pink-footed Goose Anser because a proportion of the Greylag Geese brachyrhynchus, Canada Goose Branta summering in Sweden left the country canadensis and Barnacle Goose – in a before the October count. The Swedish European context. Regional distributions of goose counts are now a part of the geese within Sweden have been published European Goose Management Platform previously (Nilsson 1988, 2000, 2013) so, census programme, established under AEWA along with information on rare species in 2016, and also contribute to the long- occurring in the country (i.e. Lesser White- term International Waterbird Count (IWC) fronted Geese and Red-breasted Geese programme coordinated by Wetlands Branta ruficollis) these will not be discussed in International. detail here. Likewise the Brent Goose Branta © Wildfowl & Wetlands Trust Wildfowl (2020) 70: 107–126 Numbers of geese staging and wintering in Sweden 109 bernicla, which, although a common passage were covered on the ground, with these migrant, stages in the country in small field counts sometimes supplemented by numbers for only short periods. observations of the birds’ morning flights from the roost to their feeding areas. Methods Intensive fieldwork during a study of the The Swedish goose counts commenced as ecology of non-breeding ecology in part of the joint Nordic Goose Programme southern Sweden provided the basis for in 1977/78 (Nilsson & Fog 1984), with the determining the survey area in southwest main aim of covering all important sites for Scania (Nilsson & Persson 1984), with new Bean Goose at monthly intervals from sites identified and included following September–April inclusive, but with all observations of geese flying to their feeding other goose species present counted as well. areas. In southwest Scania (Fig. 1a), the The surveys were made in the middle of counts were mostly undertaken by the each month, on dates coinciding with second author covering all important international waterbird counts determined feeding areas in the region, whilst in by Wetlands International. September northeast Scania the feeding grounds for counts were added from 1984 onwards, geese were covered by a team from the local following the development of the second bird club over the years (Kampe-Persson Nordic Goose Programme focussing on 2014; Kampe-Persson et al. 2017). Greylag Geese, which aimed to cover all Further north, at three of the larger sites potentially of importance for this goose staging areas in south-central Sweden species. Although during the first ten years – Tåkern, Östen and Kvismaren (Fig. 1a) – of the study (in winters 1977/78–1986/87) counts were made by teams of voluntary the counts were undertaken each month, observers counting the geese during the subsequently only four surveys were morning flights from the roost. In recent organised each year, in September, October, years, c. 300–350 sites have been covered November (supplementing the October annually in these areas during September counts) and January (coinciding with the and October. Elsewhere, in addition to these mid-winter count undertaken of all important goose sites, voluntary observers waterbirds for the IWCs). All goose species counted geese across the country during the present were counted on each occasion. selected months each year. Many of these During the first year, however, it transpired sites were included in the annual sample of that October was the most suitable month sites covered during the national waterbird for counting staging geese in Sweden except surveys undertaken in September, and also for the Greylag Goose, which to a large extent during the mid-winter (January) counts in had already left the country in October, but Sweden recorded for the IWCs. Additional had not yet started their migration at the goose counts were reported via the Swedish time of the September count. Bird Observation Portal (www.artportalen.se), In Scania, the southernmost province which was checked regularly for information. of Sweden, all important feeding areas When we found new goose sites in the bird © Wildfowl & Wetlands Trust Wildfowl (2020) 70: 107–126 110 Numbers of geese staging and wintering in Sweden (a) (b) Figure 1. Map of the study area showing (a) the count areas and locations of important goose sites in southern Sweden mentioned in the text, and (b) sites where goose counts were reported in Sweden during winter 2019/20. reports, we tried to contact the observers to abundance of these two subspecies (Kampe- recruit them to the network, asking them to Persson 2017). In order to obtain some make and report their counts on an annual indication of the timing of passage basis. migration for geese in southern Sweden, we Most counts of Bean Geese at larger sites compared the counts of geese at their in Sweden, north of Scania, were also made autumn staging sites with the numbers of during the birds’ morning flights from the geese seen migrating past the Falsterbo Bird roosting lakes to the feeding grounds, and Observatory at the south-westernmost it was not possible to separate the Tundra point of Sweden (Kjellén 2019, and the Bird Bean Goose Anser fabalis rossicus from the Observatory homepage: www.falsterbofagel Taiga Bean Geese on these occasions.