Plugging the gaps - winter studies of Eurasian Golden Plovers and Northern

SIMON GILLINGS

BritishTrust for Ornithology,The Nunnery, Thetford,Norfolk, IP24 2PU, UK, e-marl:simon.gillings@bto. org

Gillings, S. 2003. Pluggingthe gaps- winter studiesof EurasianGolden Plovers and Northern Lapwings. Study Group Bull. 100: 25-29.

Autumnmigration patterns and the winter distribution of open-habitatinland in theEast Atlantic Flyway were identifiedas major gapsin knowledge16 yearsago. For EurasianGolden Plover and NorthernLapwing in NW Europe,these gaps remain, with relativelyfew internationalsurveys and ecologicalstudies. Against a backgroundof changingclimate and modifiedfarmland landscapes, shifts in distributionand habitatuse are becomingevident. There is a needfor internationallycoordinated surveys of thesespecies in autunmand winter to estimateabundance, identify key sitesand migrationroutes and understandthe timing of migration.

INTRODUCTION The agricultural landscapesof NW Europe and Iberia haveseen major changes in the latterpart of the 20th century, Piersmaet al. (1987) reviewed the stateof knowledgecon- many of which have potentialimpacts on terrestrialwinter- cerningwader populations and migration systems in the East ing waders.The preferredfood of plovers is earthworms, AtlanticFlyway, listing 14 "majorsgaps in knowledge".Two which are relatively more abundantin pastorallandscapes of thesewere: to determineautumn migration patternsof thanin arableand it is the formerthat traditionally supported inland waders and to determine the winter distribution over large numbersof winteringplovers (Fuller & Lloyd 1981), Europe of open-habitatinland waders(Eurasian Golden and locally Curlews and Snipes.During the last 50 years, Plovers Pluvialis apricaria, Northern Lapwings however,pastoral systems have seenmajor changesin man- vanellusand Eurasian Curlews Numenius arquata). In many agement(Vickery et al. 2001), as well as in extent and dis- respectsthese remain importantgaps in our knowledge 16 tribution(Chamberlain et al. 2000). Thoughthe arableland years on. that hasreplaced pasture may potentiallysupport large num- Estuarine waders have received far more attention than bers of waders,it also has been subjectto intensemanage- terrestrialwaders, perhaps partly because of the multitudeof ment (Robinson & Sutherland 2002), which may have threatshistorically faced by populationsin estuarine affectedits suitabilityas winteringhabitat. However, it is not environments.They are alsoeasier to catchin largenumbers all doom and gloom. Whilst 90% of lowland wet grassland thanterrestrial waders. Furthermore, Lapwings and Golden has been lost (particularlyinland), many remaining areasof Plovers are amongst the most widespread of European coastalwet permanentpasture are now nature reservesor wadersduring the winter(Table 1), with at least73% of those undermanagement agreements that may benefitpassage and winteringin Britainlocated inland (Cayford & Waters 1996). wintering plovers.It is also possiblethat intensifiedsheep Thesebirds occupylarge areasof farmlandwhere they may grazingmay haveimproved some lowland pastures by reduc- be difficult to locate and census.Up-to-date information is ing swardheight. essentialto enable conservationagencies to identify and In additionto availabilityand quality of habitats,climatic designatekey sites.However, at leastin the UK, our know- factorsare also likely to influenceGolden Plover and Lap- ledge of the distributionand abundanceof thesespecies is wing distribution. Both speciesare known to respondto incomplete,and may evenbe outdated.The aim of thispaper severewinter weather, typically moving further south or west is to summarisecurrent knowledge, to highlightthreats and (Jukema& Hulscher 1988, Kirby & Lack 1993). Forecasts pressureson ploversand hint at how they may be respond- of climate changeindicate less severewinters (Hulme et al. ing. Ultimately, I emphasisethe needfor coordinatedwinter 2002) suggestingthat these movements could become a thing surveysand studies of GoldenPlovers and Lapwings through- of thepast. Climate change may act directly by alteringthermo- out Europe. regulatory costs and/or indirectly through the effects of flooding and temperatureon prey populations,their avail- A CHANGING WORLD ability, and rates of depletion. Climate changemay also affect agriculturalpractices (particularly crop selectionand Like their estuarinecounterparts, migrant or wintering ter- harvest schedules)with uncertainimpacts on prey popu- restrial waders suchas Golden Plovers and Lapwings are lations and plover foraging behaviour. dependentupon the abundanceand availability of food re- sources.Resources and their exploitationare subjectto com- STATUS AND DISTRIBUTION plex interactionsbetween biological (competition), climatic (winter severity), and anthropogenicfactors (agricultural In the non-breedingseason, NW Europe supportsGolden regimes,hunting). Ploversfrom threebiogeographic flyways totalling 1.6-2.0

25 Bulletin 100 April 2003 26 Wader Study Group Bulletin

Table 1. Percentage of squares surveyedfor winter atlas fieldworkthat held variouswader species. B & I = Britainand Irelandfrom Lack (1986), 3862 10-km squares. NL = November distributionfrom SOVON (1987), c.1760 5-km squares. Both provided near complete geographic coverage.

Species B & I (%) NL (%)

EurasianOystercatcher Haematopus ostralegus 40 37 Ringed Plover Charadrius hiaticula 27 9 EurasianGolden Plover Pluvialis apricaria 57 50 Grey Plover Pluvialis squatarola 16 19 Vanellus vanellus 79 86 Red Knot Calidris canutus 12 11 Common Snipe Gallinago gallinago 76 72 Eurasian Curlew Numenius arquata 57 67 Redshank Tringa totanus 42 22

million individuals (Wetlands International 2002). Just one servedas refugesduring occasionalsevere winter weather. Lapwing populationis identifiedin the region,comprising Furthermore,for thesewide-ranging species for which site- 2.8-4.0 million (Wetlands International 2002). The basedconservation may be lessappropriate, it is particularly GoldenPlover's breeding origins are in the tundraand taiga important to have knowledge of the effects of land-use zonesof Iceland,Scandinavia and European Russia and the changeacross large areasof the countryside.As a resultof moorlandsof Britain and Ireland. The Lapwingsoriginate the changesin pasture and plover distributionmentioned from more temperatezones throughoutEurope. Broadly above,a high proportionof GoldenPlovers and Lapwings speaking,during autumnand winter, both Golden Plovers winteringin Britain now occupiesthe predominantlyarable andLapwings occupy the Netherlands, Germany, Britain and zone of Britain where therehave beenvery few ecological Ireland, France and Iberia, with fewer in the Mediterranean studies(Mason & MacDonald1999; S. Gillings,unpublished basin, Middle East and North Africa. Areas in the north of data) on which managementrecommendations might be thisrange including Denmark, the Netherlands and Germany based. are mainly used as stopoveror moulting sites in autumn (Cramp & Simmons1983; Byrkjedal& Thompson1998). MIGRATION STUDIES There are few sourcesof information for monitoring trendsin winter. Interpretationof periodic surveysis ham- Understandingmovements requires coordinated counting peredby incompletecoverage of the rangeat any giventime and ringing studies.Excellent work, much of it by amateur andthe species'tendency to shiftdistribution in responseto ornithologists,during autumn and early winter in Denmark, cold weather(e.g. Delany et al. 1999). In Great Britain, the Germanyand the Netherlandshas shedimportant light on Wetland Bird Survey (WEBS) providesmonthly counts of understandingmovements of GoldenPlovers in thesecoun- theproportion of thepopulation of bothspecies that winters tries (Jukema et al. 2001). However, movementsto (and on coastaland inland wetlandsites (Musgrove et al. 2001). within) countriesfurther south and west later in the winter Analysesof data from estuariesshows marked increases on are lesswell understood.In the Netherlands,large numbers easterncoasts since the 1970sand particularly since the mid- of birdsare caughtannually by traditionaltechniques (Juk- 1980s (Fig. 1, S. Gillings, unpublishedanalysis). Whether emaet al. 2001) providingmuch information on movements thesechanges are dueto redistribution,population increase and demography.Interpretation of thesering-recoveries is or habitat shift is unclear. complicatedbecause high reportingrates in Franceand Ibe- However, simultaneousto this increasein the east,a par- ria mayhave been due to highhunting pressure, whereas low allel declinein numbersin central(R.J. Fuller pers.comm.) reportingrates in Britain may be dueto difficultiesof catch- andwestern Britain has occurred. This is particularlyevident ing adult plovers. Between 1909 and 2000, only 5,837 in the distributionof flocksreported in the BritishTrust for GoldenPlovers were ringedin Britain andIreland of which Ornithology/JointNature ConservationCommittee Winter only50% werefully grown(Fig. 3). For Lapwings,the pro- FarmlandBird Survey(Fig. 2), which showsa moreeasterly portionof full-grownbirds ringed is muchsmaller: only 6% winter distributionduring 1999-2002 comparedwith the of totalof 214,897birds (Fig. 3). Furthermore,it is likely that early 1980s(see Winter Atlas, Lack 1986).Whilst thesere- a high proportionof thesewere caughtas breedingadults sultsare based on casually collected records and may be biased ratherthan in winter.By contrast,in theNetherlands, at least to someextent by the distributionof observers,records for 1,000-2,000Golden Plovers, all fully grown,have been cap- other farmland species(e.g. thrushes,finches, buntings, turedannually since the mid-1970s. shownin grey in Fig. 2) indicategeographic coverage was To betterunderstand the dynamicsof GoldenPlover and good. Other shiftsin distributionare evidentfrom coordi- Lapwingmovements requires targeted catching and ringing natedcounts showing a decreasein theNetherlands and in- of full-grownbirds during autumn and winter especially in creases(or birdsremaining later) in Denmarkand northern Britain and Ireland, but ideally also in Iceland,France and Germany(van der Windenet al. 1997).Similar distribution Iberia.In manycountries, plovers are regularly observed by changesmay be occurringfurther south, for examplein Por- birdwatchersand probably more use could be madeof colour- tugal (D. Leitao pers.comm.), but to what extentis unclear. markingto understandmovements as has worked so success- Distributionchanges have repercussions for conservation. fully for otherspecies, such as Black-tailed Godwits Limosa The new sitesthat becomeoccupied may need protection. limosa (Gill et al. 2001). However,sites that are abandonedmay still needto be con- • Bufietin100April2003 Gillings:Winter studies of Eurasian Golden Plovers and Northern Lapwings 27

2500%

•,2000%

._c1500%

•'1000% -=500%

1970 1975 1980 1985 1990 1995 Year

Fig. 1. Trends in the numbersof EurasianGolden Plovers (open circles)and NorthernLapwings (solid circles)on east coast estuaries of Britainin December between 1970/71 and 1999/2000. Data from WEBS, index set to 100% in 1970/71 (S. Gillingsunpublished analysis).

THE FUTURE the population in Ireland is found in SPAs (4% of the biogeographicpopulation; Stroud et al. 2001). The majority In a changingworld, our knowledgeof the statusand ecol- of these sites are coastal and none include areas of intensive ogy of migrating and wintering Golden Plovers and Lap- agriculturewhere much of the remainingpopulation occurs. wingsmay be incompleteand potentiallyoutdated. This is Habitatprotection will only be possiblewith updatedinfor- an untenable situation if we are to meet future conservation mation on abundance and distribution. Even if site-based challenges.The GoldenPlover is listedin Annex I of the EC conservation measures are deemed unsuitable for terrestrial Birds Directive (79/409/EEC). This means that Member plovers away from wetlands,an equivalentlevel of new Stateshave a duty to classifytheir most suitablewintering informationwill be requiredto facilitatetheir conservation groundsas SpecialProtection Areas (SPAs). Currentlyonly in the wider countryside. 22% of the winteringpopulation in GreatBritain and 6% of

PloverEurasian Golden NorthernLapwing

Fig. 2. The distributionof EurasianGolden Ploversand NorthernLapwings in Britainduring November-February1999/2000 to 2001/2002 based on casual recordsof flocksof 100 or more individuals(single species or both combined)contributed for the BritishTrust for Orni- thology/JointNature ConservationCommittee Winter Farmland Bird Survey. In grey is shownthe distributionof 10-km squaresfrom which recordsof all other species were received- i.e. approximatingto coverage. Note that only lowlandfarmland was surveyed, hence some white gaps represent the uplands of , north and Scotland.

Bulletin 100 April 2003 28 Wader Study Group Bulletin

350 (a) Eurasian Golden Plover 3OO

250 c• 200

'•_ • 150

< 100

5O

1909 1919 1929 1939 1949 1959 1969 1979 1989 1999

7OOO (b) Northern Lapwing 6000

5000

4000

3000

2000

lOOO

o 19o9 1919 1929 1939 1949 1959 1969 1979 1989 1999

Fig. 3. Annual British& Irish ringingtotals for (a) EurasianGolden Plover and (b) NorthernLapwing from 1909 to 2000. Bars are divided into totals of the numberof fully grown birds ringed (black section) and the number of pulli ringed (white section). Note that priorto 1931 the age at ringingwas not available (grey bars).

SO WHAT IS NEEDED? SOME THOUGHTS AND non-breedingseason and where are the mostimportant QUESTIONS sites? 3. What are the migrationroutes? The gapsin knowledge,highlighted at the beginningof this 4. What is the timing of migratory movementsacross the article, still exist in several countries, and much could be non-breedingrange, and what influencesthis pattern? gained from a coordinatedsurvey of Golden Plovers and Lapwingsthroughout Europe. This shouldbe augmentedby Any survey designedto answerthese questionswould ringingand ecological studies aimed at answeringthe follow- needto be coordinatedwith moreor lesssynchronised counts ing questions: in different countriesto minimisedouble-counting or miss- ing flocksfor thesehighly mobile species. Owing to the lati- 1. How manyGolden Plovers and Lapwings are there in W tudinalrange of the speciesthrough autumn and winter the Europeduring migration and in winter? surveyperiod would have to be lengthy. It would need to 2. How many occurin eachcountry at differenttimes of the startin Octoberto recordthe main moultingand passage sites

Bulletin 100 April 2003 Gillings:Winter studiesof EurasianGolden Ploversand NorthernLapwings 29

in Iceland,Britain, Sweden,Denmark and Germany.Counts the Middle East and North Africa. Oxford University Press,Oxford. would have to be made in November and December when Delany, S., Reyes, C., Hubert, E., Pihl, S., Rees, E., Haanstrata L. & van Strien, A. 1999. Resultsfrom the International Waterbird Cen- numberspeak in the Netherlandsand Britain, and continue sus in the Western Palearctic and Southwest Asia 1995 and 1996. into Januaryand Februaryas it seemsthat birds then move Wetlands InternationalPublication No. 54. Waginengen,The Nether- into Ireland,France, Spain, Portugal and Italy. Would it be lands. possiblefor monthlysurveys to be coordinatedacross the Fuller, R.J. & Lloyd, D. 1981. The distribution and habitats of winter- wholewinter range? These synchronised counts would pro- ing Golden Plovers in Britain, 1977-1978. Bird Study 28: 169-185. vide population estimateswithout double counting and Gill, J.A., Norris, K., Potts, P.M., Gunnarsson, T.G., Atkinson, P.W. would recordthe early arrivalsin the southor hangers-onin & Sutherland, W.J. 2001. The buffer effect and large-scalepopula- tion regulationin migratory birds. Nature 412: 436-438. the north? Such base-line information would be invaluable Itulme, M., Turnpenny, J. & Jenkins, G. (2002). Climate changesce- shoulddistributions change further in the future. Repeating nariosfor the UnitedKingdom: the UKCIP02 briefingreport. Tyndall surveysin each month would alsoprovide movementand Centre for Climate Change Research, School of Environmental timing information. Sciences,University of East Anglia, Norwich, UK. 14pp. What arethe logisticsof surveyingin differentcountries? Jukema, J. & I-Iulscher, J.B. 1988. Terugmeldingskansvam geringde The Netherlandshas coordinated near-complete censuses in GoudplevierenPluvialis apricaria in relatie tot doe strengheidvan de winter. Limosa 61: 85-90. the past(e.g. van der Winden1997), but thisis almostcer- Jukema, J., Pierstoa, T., I-Iulscher, J.B., Bunskoeke, E.J., Koolhaas, tainlyimpossible in manyother countries. How shouldsur- A. & Veenstra, A. 2001. Goudplevierenen wilsterfiappers:eeuwende veysbe carriedout in thoseplaces? In Britain, a combined fascinatie vooetrekvogels. Fryske AcademyKNNV Uitgeverij, Louw- approachof countson knownimportant wetland, coastal and ert/Utrecht.(In Dutch with Englishsummary). terrestrialsites plus a samplesurvey of other areasmay be Kirby, J.S. & Lack, P.C. 1993. Spatialdynamics of winteringLapwings the only way to achievereasonably good coverage and accu- and Golden Plovers in Britain and Ireland, 1981/82 to 1983/84. Bird Study40: 38-50. racy. Lack, P.C. 1986. The atlas of wintering birds in Britain and Ireland. I invite commentsfrom other peoplewho are interested Poyser,Calton. in theseproblems, particularly concerningthe need for a Mason, C.F. & MacDonald, S.M. 1999. Habitat use by Lapwings and surveyof passageand wintering terrestrialplovers and the Golden Plovers in a largely arable landscape.Bird Study 46: 89-99. waysin whichone might be coordinatedand designed, and Musgrove, A.J., Pollitt, M.S., Hall, C., Hearn, R., Holloway, S.J., the timescalenecessary. Marshall, P., Robinson, J. & Cranswick, P.A. 2001. The Wetland Bird Survey 1999-2000: Wildfowl and Wader Counts.BTO/WWT/ RSPB/JNCC, Slimbridge. ACKNOWLEDGEMENTS Pierstoa, T., Beintema, A.J., Davidson, N.C., Munster, OAG & Pienkowski,M.W. 1987.Wader migration systems in the EastAtlan- I would like to thankRob Fuller, TheunisPiersma and Joop tic. Wader Study Group Bull. 49 (Supplement1): 35-56. Jukema for useful discussion and Wally Johrrson,Phil Robinson, R.A. & Sutherland, W.J. 2002 Post-war changesin arable Atkinson,Juliet Vickery andBen Fraserfor commentson an farming and biodiversity in Great Britain. J. App. Ecol. 39: 157-176. earlier draft. SOVON 1987. Atlas van de Nederlandsevogels. SOVON, Arnhem Stroud, D.A., Chambers, D., Cook, S., Buxton, N., Fraser, B., Clem- ent, P., Lewis, P., McLean, I., Baker, H. & Whitehead, S. (eds.) REFERENCES 2001. The UK SPA network: its scope and content. JNCC, Peterbor- ough. Byrkjedal, I. & Thompson,D.B.A. 1998. Tundraplovers: the Eurasian, Wetlands International. 2002. Waterbird population estimates- third Pacific and American Golden Plovers and Grey Plover. T. & A.D. edition. WetlandsInternational Global SeriesNo. 12, Wageningen, Poyser,London. The Netherlands. Cayford, J.T. & Waters, R.J. 1996. Populationestimates of waders van der Winden, J., Gerritsen, G. & van Roomen, M. 1997. Prelimi- Charadriiwintering in GreatBritain, 1987/88-1991/92.Biol. Cons.77: nary resultsof a country-widesurvey of stagingGolden Plover, Lap- 7-17. wing and Curlew in The Netherlands.Wader StudyGroup Bull. 86: Chamberlain, D. E., Fuller, R. J., Bunce, J. C., Duckworth, J. C., & 31-32. Shrubb, M. 2000. Changesin the abundanceof farmland birds in re- Vickery, J.A., Tallowin, J.R., Feber, R.E., Asteraki, E.J., Atkinson, lation to the timing of agricultural intensificationin England and P.W., Fuller, R.J. & Brown, V.K. 2001. The managementof lowland Wales. J. App. Ecol. 37: 771-788. neutralgrasslands in Britain: effectsof agriculturalpractices on birds Cramp, S. & Simmons, K.E.L. 1983. Handbookof the birds of Europe and their food resources.J. App. Ecol. 38: 647-664.

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