Ole Thorup

Population size and trends

Available data on population sizes

There has never been a nationwide survey of the common and dispersed species like lapwing. However, there have been four countrywide programmes surveying breeding birds in the most important bird sites: In 1964–1972, 1978–1981 and again 1993–1996 volunteers from DOF (BirdLife Denmark) covered a large number of sites (1, 2, 3, 4), and in 1987–1989 the Ministry of Environment and Ornis Consult covered most of the Danish Special Protection Areas (5). Lapwing was one of the target species during these surveys. For this review, data published in grey literature as well as unpublished data and data on DOF’s bird database (6) have been searched for comprehensively (see also acknowledgements), including the sets of regional reports reporting the results from the 1978–1981 survey (list in 3) and the 1993–1996 survey (list in 7).

In addition to the abovementioned projects and programmes, there has been a baseline monitoring of lapwings with a very variable extent over the years. These counts were performed by a combination of different players: the Ministry of the Environment, counties, municipalities, nature protection charities, DOF, and private volunteers covering their favourite site. The key meadow bird site Tipperne was surveyed annually since 1928. In the second half of the 1970s annual or quite regular breeding bird counts were started on several other important sites for meadow birds. The highest coverage was obtained 1978–2003. After 2003 the number of national and regional baseline counts was reduced and with the closure of the counties 2006/2007 a further reduction took place. 2007–2016 there were still annual counts of lapwings in several of the most important Danish sites: Tøndermarsken, Mandø koge, Værnengene, Tipperne, Agger Tange, Vejlerne, Roskilde Fjord and Nyord, and the entire Wadden Sea and southern Læsø were counted with regular intervals.

When preparing data for the Breeding Waders in Europe 2000 assessment (8), all available count data 1993–1999 were analysed systematically, and some arable land plots (totalling 26 km2) widely distributed in Denmark were surveyed and used for an estimate (or perhaps rather a guesstimate) of arable land populations of lapwing (9). Because 1993–1999 is probably the time period with the best coverage ever in Denmark of lapwing, population estimates from this analysis has been used as the baseline for other population size estimates of this species. In order to estimate trends before and after 1993–1999, a number of sites with long time series have been selected with the criteria, that at minimum one estimate of the population size of the species is available in each of the periods 1975–1981, 1992–1998, and 2006–2015.

Available data on trends and distribution

Three ATLAS projects with an extremely high coverage (10, 4, 11) have provided very exact information on the national distribution and changes in distribution over the years, also for the otherwise less well surveyed species with important numbers breeding outside ‘bird sites’, in particular on inland farmland.

An important source for trends in populations of lapwing are indices calculated from DOF’s point-count programme [D1] (12). In this programme, birds are counted repeatedly for five minutes once a year on the same date on a large number of appointed points, and indices and standard errors are calculated using the software TRIM (13).

Population sizes and trends

Lapwings are widespread breeders all over Denmark, and in the three ATLAS periods 1971–1974, 1993–1996 and 2014–2017 lapwings were found breeding in 84–88% of the 2169 5×5 km ATLAS squares (10, 4, 11). For very many years, the huge majority of the Danish Lapwings were breeding in arable land. Wet grassland housed many breeding Lapwings but were of relatively less although increasing importance (8, 14).

At 90 lapwing coastal grassland breeding sites, lapwings have been counted regularly 1976–2019 (Fig. 1). Except for three years with much higher numbers 1983–1986, lapwing numbers at these 90 sites have been relatively stable, with small fluctuations only, during the entire period.

Most point count routes are inland routes, and the indices mainly reflect trends in arable land and to a smaller extent also in inland grassland. The first six years of the programme 1976–1981 the indices fluctuated a lot, but since 1981 the indices show a slow but steady decline (12) and the 2012–2018 level is at only 40% of the 1981 level.

Figure 1. Number of breeding pairs of lapwing at 90 coastal grassland sites with long time series (blue line). Gap filling has been used for sites and years without counts (see 15). Furthermore, indices for lapwing from the Danish point count programme (orange triangles).

In the 1990s there were approximately 38,000 pairs of lapwings in Denmark (Table 1). 8,730 from this estimate were counted pairs (23%), and a much higher percentage of the wet grassland breeding birds were counted (72%) than of the arable breeding birds (4%). The number of lapwings breeding at the 90 regularly counted sites 1976–2019, depicted in Fig. 1, constituted approximately 5% of the estimated total, 18% of the wet grassland breeding pairs, and 26% of the lapwing pairs breeding on coastal wet grassland.

In 1996, at the first total count of the Danish Wadden Sea including mainland polders, the 3,603 pairs constituted 9% of the estimated national total. At the next three counts in 2001, 2006 and 2012, the Wadden Sea lapwings declined continuously (14, 16), and the 1,889 pairs in 2012 were only 52% of the 1996 number. The strongest decline took place in the arable breeding fraction, in which only 34% of the 1996 number were counted in 2012. In Wadden Sea grassland lapwings showed a 21% decline from 1996 till 2012.

Based on point count indices and arable lapwing counts in the Wadden Sea, the number of lapwings breeding on arable land are estimated to have declined from approximately 37,000 pairs in the late 1970’s to 15,000 pairs in 2012–2014 (Table 1). On coastal grassland, in contrast, numbers seem to have been fairly stable in the same period, at approximately 8,000 pairs (Table 1). On inland wet grassland, the very sparse recent data may indicate a decline from approximately 3,500 pairs in the late 1970’s to 2,500 pairs in 2010–2015 (Table 1), but this is largely a ‘guesstimate’. The first part of this decline from 3,500 pairs in the late 1970’s to 3,000 pairs in the mid 1990’s is supported by data from two countrywide surveys of ‘bird-sites’ (3, 4).

Discussion

Outside some particularly important wet grassland sites, where meadow bird management and land use are specifically meadow bird friendly, wet grassland is preserved solely with agri-environment schemes, prescribing some general and not very strict rules concerning grazing schedules and densities and/or season open for mowing/cutting of grass. Such general habitat management seems to suit Lapwings well, when it comes to coastal wet grassland.

An important issue concerning the conservation is the serious conservation problems lapwings face in Denmark outside wet grassland. Historically, the huge majority of the breeding Lapwings in Denmark were not found on meadows/wet grassland but in arable land, in particular spring sown cereals. This fraction of the lapwing population is rapidly becoming smaller. In particular two changes in the farming practises have contributed to the declines since the 1970s: a gradual but large scale conversion from spring sown to autumn sown cereals (17) and, during the last 15 years or so, an increasingly widespread use of levelling spring sown cereal fields some weeks after sowing and levelling grass fields in the main Lapwing chick season in May (9).

Estimation and evaluation of population sizes and thereby recent trends are becoming increasingly difficult for lapwing, as baseline counts have been reduced markedly the last ten years. There are still good counting programmes in the best meadow bird sites Vejlerne and Tipperne and with six years intervals also in the Danish Wadden Sea. Lapwing is not covered by national monitoring programmes that only includes bird species listed in the EU Birds Directive in Annex I. Additional monitoring is a patchwork of different schemes and programmes dependent of decisions by DOF and other NGO organisations, municipalities and initiatives by private volunteers. Without doubt, the possibility to perform future evaluations of population sizes and trends would improve considerably if there would be some kind of systematic national monitoring scheme that also included lapwing outside the best meadow bird sites and the Wadden Sea.

There is virtually no systematic data collected on breeding success of lapwings in Denmark. There is a programme at Tipperne monitoring nest success since 1986 and chick survival since 1998 (18), and breeding success in a minute farmland population on the island of Fyn has been followed since 2011 (19). Scaling up such breeding success monitoring programmes, in particular for lapwings breeding on farmland,  would improve the possibility to address the key problems for the species.

AcknowledgementS

This review is largely an extract and update of a talk at a meadow bird workshop in Haapsalu, Estonia in 2014 and an article elaborated for the proceedings of this workshop (15). Yvonne Verkuil, Vojtěch Kubelka and two anonymous referees improved the original article significantly.

Ole Amstrup, Jens Jørgen Andersen, Hans Christophersen, Niels Harald Jensen, Jørgen Peter Kjeldsen, Henrik Haaning Nielsen and Palle A. F. Rasmussen contributed with unpublished survey data for this review. This is greatly appreciated.

References

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  2. Ferdinand, L. 1980. Fuglene i landskabet. Dansk Ornithologisk Forening, København. [in Danish]
  3. Dybbro, T. 1985. Status for danske fuglelokaliteter. Dansk Ornithologisk Forening, København. [in Danish]
  4. Grell, M.B. 1998. Fuglenes Danmark. Gad. [in Danish]
  5. Falk, K. & S. Brøgger-Jensen. 1990. Fuglene i internationale beskyttelsesområder i Danmark. Miljøministeriet, Skov- og Naturstyrelsen. [in Danish]
  6. DOF. 2016. Dansk Ornitologisk Forenings bird database at http://www.dofbasen.dk. Accessed March 2016. [in Danish]
  7. DOF. 2016. Publikationsbase. http://www.dof.dk/om-dof/publikationer/publikationsbase Accessed March 2016. [in Danish]
  8. Thorup, O. 2006. Breeding Waders in Europe 2000: a year 2000 assessment. International Wader Studies 14: 1–142.
  9. O. Thorup unpublished data
  10. Dybbro, T. 1976. De danske ynglefugles udbredelse: Resultaterne af Atlas-projektet, kortlægningen af Danmarks ynglefugle 1971–74. Dansk Ornithologisk Forening, København. [in Danish]
  11. DOF. 2018. ATLAS maps from the 2014–2017 ATLAS project published on http://www.dofbasen.dk/atlas/. Dansk Ornitologisk Forening. Accessed August 2018. [in Danish]
  12. Moshøj, C.M., D.P. Eskildsen, K.S. Jørgensen, M.F. Jørgensen & T. Vikstrøm. 2019. Overvågning af de almindelige fuglearter i Danmark 1975–2018. Årsrapport for Punkttællingsprogrammet, Dansk Ornitologisk Forening. [in Danish with English summary]
  13. Pannekoek, J. & A. van Strien. 2005. TRIM 3 manual (Trends and Indices for Monitoring data). Statistics Netherlands, Voorburg. Accessed August 2018. https://www.cbs.nl/en-gb/society/nature-and-environment/indices-and-trends–trim–
  14. Thorup, O. & K. Laursen. 2008. Status of breeding Oystercatcher Haematopus ostralegus, Lapwing Vanellus vanellus, Black-tailed Godwit Limosa limosa, and Redshank Tringa totanus in the Danish Wadden Sea in 2006. Dansk Orn. Foren. Tidsskr. 102: 255–267.
  15. Thorup, O. 2018. Population sizes and trends of breeding meadow birds in Denmark. Wader Study 125(3): 175–189.
  16. Thorup, O. & K. Laursen. 2013. Ynglefugletællinger i det danske Vadehav 2012. Fugleåret 7 (2012): 223–232. Dansk Ornitologisk Forening, København.  [in Danish]
  17. Danmarks Statistik. 2016. Afgrøder i dansk landbrug 2016. https://www.dst.dk/Site/Dst/Udgivelser/nyt/GetPdf.aspx?cid=21927. Accessed November 2018. [in Danish]
  18. Thorup, O. & T. Bregnballe. 2018. Ynglefuglene på Tipperne 2017. Fugleåret 2017: 169-174. Dansk Ornitologisk Forening. [in Danish]
  19. Andersen, N. 2019. I Vibens tjeneste. Vibeforår i landbrugslandet, opdatering 2019. Unpublished report. [in Danish]  

published: 02/2020

AutHor

Ole Thorup
V. Vedsted Byvej 32, DK-6760 Ribe
Email: olethorup.fugleliv@gmail.com