Origin and Movements of Grey Plovers <I>Pluvialis Squatarola</I> Ringed

Origin and movements of Grey Plovers Pluvialis squatarola ringed in Germany

Klaus-Michael Exo & Svea Wahls

Exo, K.-M. & Wahls, S. 1996. Originand movementsof Grey PloversPluvialis squatarola ringed in Germany. Wader Study Group Bull. 81: 42-45. The general migrationroutes of waders usingthe East Atlanticflyway are reasonablywell known. However,detailed studies on the migrationroutes and the originof Grey Plovers stagingalong the Germancoasts are very limited. We analyzedunpublished recoveries of birds ringedby the schemesof the VogelwarteHiddensee and the VogelwarteHelgoland. A total of 2 896 Grey Ploversringed in the period1909-1994 resultedin 44 recoveries. Of these, 22 could be used for further analyses. The recoveriesindicate that Grey Ploverspassing along the German coastsoriginate from arcticRussia. The winteringarea rangesfrom north-eastScotland to the Gulf of Guinea. Grey Ploverswintering in Britainmay leave the Wadden Sea later than birdswintering further south. Two recoveriesfrom Tunisiaand Egyptindicate that some of the birdsswitch over to a more easterlyroute, in particularyoung birds may migrateon a widerfront. Thoughthe majorityof birds were ringed at the Balticcoast there is no direct evidencethat first calendar year birds stagingat the Balticcoast on their first autumnpassage migrate step-by-step and stopover in the Wadden Sea again to fill up their energy reserves. K.-M. Exo & S. Wahls, Institutfor Vogelforschung,An der Vogelwarte21, 26386 Wilhelmshaven,Germany.

INTRODUCTION Ploversare typicallong-distance migrants. Those birds migratingthrough the Wadden Sea are assumedto The EastAtlantic flyway population of Grey Plovershas originatefrom breedinggrounds in arctic Russia, increasedconsiderably over the last decades (Meltofteet eastwardsto about80 ø E (Taimyrpeninsula, Cramp & al. 1994; R0sner et al. 1994; Cayford & Waters 1996). Simmons 1983). The winteringareas of these birds reach Basedupon count data Meltofteet al. (1994) estimateda as far south as to the Gulf of Guinea (Branson& Minton total of at least 166 000 birds. Almost the entire East 1976; Cramp & Simmons1983). Atlanticflyway population uses the WaddenSea in May to buildup body reservesfor their furtherflights to the The aim of this shortcontribution is to supplysome more breedinggrounds. The majorityof the populationpasses detailson migrationpatterns by makingstill unpublished throughthe Wadden Sea again in autumn. In mild winters recoverydata of Grey Ploversringed by the schemesof morethan 10% of the flywaypopulation may winterin the the ' VogelwarteHiddensee' and the ' VogelwarteHelgoland Wadden Sea (Prokosch1988; Meltofte et al. 1994). available. At least some of the recoveriesringed by other Therefore, the Wadden Sea is of outstandinginternational Europeanringing schemes have been published importanceto the East Atlanticflyway population of Grey elsewhere(e.g. Branson& Minton 1976; Pienkowski& Plovers. However,during autumn passage a considerable Evans 1984; Prokosch1988; Meltofte 1993). Ringing numberof Grey Plovers,especially first calendar year recoveriesare an importanttool in depictingmigration birds, use the Balticcoast as a staging area. patterns.

Whilethe general migration routes of waders are reasonablywell known,detailed studieson the originand migrationroutes of Grey Ploversare very limited. Grey

42 RINGING AND RECOVERY TOTALS ORIGIN AND MIGRATION

A total of 2 896 Grey Ploverswere ringedin Germanyby Ringingrecoveries must be analyzedand interpreted with the end of 1993 (Hiddensee 1964- 1993:1 481, great caution (e.g. Perdeck 1977; Busse 1986; North Helgoland1909 - 1993:1 415). Up to the beginningof 1987). For example,the recoveryprobability in different 1995 the 2 896 ringingshad resultedin 44 recoveries areas is severelybiased by hunting,observation and/or (Hiddensee:32, Helgoland:12). Controls(retraps, ringingas well as reportingactivities of man. According resightingsetc.) near the ringingsite duringthe same to thefinding circumstances the recoverieswere grouped seasonare not considered. The overallrecovery rate for intotwo categories:'found dead and 'hunted (EURING both schemesis about 1.5%. The recoveryrate of birds codes 10, 11 and 19). As Figure 1 indicates,the ringedby the scheme of Hiddensee,mainly along the distributiondiffers markedly according to the finding German Balticcoast is higherthan of birds ringedwith circumstances.Half (22) of all birds recoveredwere'shot, Helgolandrings, prevailingly in the Wadden Sea (2.2% vs. about 91% (20) of these in France. Therefore,we 0.9%). Mostof the birdsrecovered were ringedin the excluded all birds recovered as 'hunted' or otherwise killed 1980s (1955-79:10, 1980-89: 30, 1990-94: 4). by manfrom the generalanalysis, exceptions are mentioned.As in mostspecies the distributionand About 86% (38 of 44) of the birds recoveredwere ringed migrationpatterns are representedbest by the category duringautumn migration,from Augustto October 'founddead'. However,the category'found dead' may (Table 1). The majorityof these birds (84%, 32 of 38) also include some birds whose death was in fact caused were ringedat the German Balticcoast, mainlyon the by hunting.In additionto the 15 birdsreported as 'found islandof Langenwerder(54o2 ' N, 11ø30' E, districtof dead'seven controls are includedin the analyses. Rostock). From those 38 ringings,25 birds (66%) were Therefore, a total of 22 recoveries could be used for caughtas first calendaryear birds,24 (63%) of them at furtheranalyses. Accordingto the age of ringingthese the Balticcoast on autumnpassage. There are onlyfive recoverieswere groupedinto two age classes(a) first (11%) recoveriesof birdsringed during spring passage in calendaryear birdsringed during their first autumn (13 May. Accordingto their seasonaloccurrence (see above) recoveries),and (b) birdsolder than firstcalendar year these birds were caught in the German Wadden Sea. (nine).

Table 1. Numbersof Grey Ploversringed by Germanringing 25 schemesand recoveredby the end of 1993. The data are split hunted accordingto the ringingregion, season and age at ringing. 2O " IIIIII n = 22 Autumn Spring Ringingregion first full full breeding Total 15 year grown grown adult

German Baltic 24 8 32 10 coast o German Wadden 1 5 5 11 - Sea

Taimyr 1 1 found deed Total 25 13 5 1 44 - controls n=22

Forthe evaluationdifferent ringing activities during spring and autumn migrationas well as differentringing activities in both areas have to be taken into account. However, both (1) the total numberof birdsringed in both areas on springand autumnpassage, respectively, as well as (2) 0 I i i i i i i 11111111i the numberof first calendar year birds ringed along the Balticcoast and in the Wadden Sea, respectively, correspondwith the countdata. Grey Ploversas most otherwaders use the Balticcoast as a stopover site almostexclusively during autumn migration, whereas on springpassage only very small numbers rest there (Kube autumn • winter • spring • summer & Struwe 1994). Furthermore,a muchhigher proportion of juvenilesthan of adultbirds uses the BalticSea as a Figure1. Recoverynumbers of Grey Ploversringed in Germanysplit stagingsite. Similarly,the numberof ringedand accordingto recoveryregions, the seasonof recoveryand the recoveredjuveniles was much higherin the Baltic. recoverycircumstances: (a) shot, (b) founddead/controls. Note l•e differentscales. n - numberof recoveries;autumn: August - October,winter: November- February, spring: March - May, summer: June/July.

43 The recoveriesof Grey Ploversringed on theirpassage throughGermany confirmthe commonview that most of them followa migrationroute along the East Atlantic flyway. One male birdthat was ringedin the Wadden Sea duringspring migration and controlledon the Yamal Peninsula(Figure 2b) givesfurther evidence that Grey Ploverspassing along the German coast originatefrom arcticRussia. So does one colour-ringedfemale which was ringedduring incubation on Yamal Peninsulain July 1993 and seen on several occasions in the East Frisian WaddenSea duringspring and autumnmigration 1993 to 1995 (pers.obs.). Branson& Minton(1976) and Meltofte (1993) mentionedthree furtherrecoveries of birdsringed in Europeand foundat Siberianbreeding grounds.

The winter recoveries from Britain, France, the Iberian peninsula,the Canary islands,Gabun, Tunisia and Egypt (Figure2a, b) indicatethat the winteringarea of Grey Ploverspassing along the German coasts ranges from north-east Scotland in the north down to the Gulf of Guinea/Gabon in the south.

Whereassome birdsjust pass overto the NorthSea in orderto winter in Britain,the majorityseem to migrate furthersouth to Africanwinter quarters. There are no recoveriesreported from Britainbefore December, whereas recoveriesfrom more southerlyareas, e.g. Franceturn up from Augustonwards (Figure 2a, b). This may indicatethat Grey Ploverswintering in Britainmay leave the Wadden Sea relativelylate, whereas birds migratingfurther south start earlier (c.f. Townshend1982; Cramp& Simmons1983; Meltofte1993). Includingthe birds recoveredas 'hunted'Grey Ploversseem to arrive in Francefrom end of Augustonwards.

At least some of the birds winteringin Britain use the WaddenSea as a stagingsite duringspring and autumn migration(Figure 2b; c.f. Branson& Minton 1976; Pienkowski& Evans 1984; Prokosch1988). Accordingto the recoveriesgiven by Branson& Minton(1976) some of the birdswintering in Britainstop over at the Swedish Balticcoast. However, until now it is uncertainwhether these birds migratevia the Balticcoast withoutresting in the WaddenSea or if they migratestep-by-step. Including the birdsrecovered as 'hunted'there is onlyone recovery from the SwedishBaltic coast ol a Grey Ploverringed in the German Wadden Sea (Figure 1). Furthermore,it is uncertainwhether first calendar year birdsusing the Baltic coast as a stagingsite on their first autumnpassage stop over in the WaddenSea againto fill up their body reservesbefore migratingfurther south or fly directlyto theirwintering sites. Thoughthere is no directevidence based on recoveries,it is assumedthat juvenilebirds migratestep-by-step, whereas most adults make non-stop Figure2. Ringing(•.) and recovery(©) placesof GreyPlovers flightslrom the Wadden Sea to their breedingand ringedin Germany.The firstnumber beside each symbolindicates winteringgrounds, respectively (c.f. Glutzyon Blotzheim the monthof recoveryand the secondnumber (only in 2 a) the year of life. (a - upper)birds ringed on theirfirst autumn passage, (b et al. 1975). lower)sum of all otherage classes.Additionally, the placeof one male (•,) capturedand retrappeda year lateron the breeding groundson TaJmyrPeninsula (Pjasina Delta; DFH 6326001)as well as the breedingplace of onefemale ((•) colour-ringedon Yamal peninsulaand observedin the EastFrisian Wadden Sea are indicated.

44 However,two recoveriesfrom Tunisiaand Egyptindicate REFERENCES that at least some of the birds stagingin Germany switch over to a more easterlyroute. These recoveries Branson,N.J.B.A. & Minton, C.D.T. 1976. Moult, measurements correspondwith the morphometricalanalyses of birds and migrationsof the GreyPlover. BirdStudy 23: 257-266. winteringin Tunisia (van Dijk eta/. 1986). Accordingto Busse,P. 1986. Theoreticalmodels in an interpretationof recovery van Dijk eta/. (1986) a smallproportion of Grey Plovers patterns. Ring 11: 211-228. winteringin Tunisiabelongs to the west Palearctic breedingpopulation, whereas the majorityis of east Cayford,J.T. & Waters,R.J. 1996. Populationestimates for waders Palearcticorigin, breeding east of Taimyr. It is assumed Charadriiwintering in Great Britain,1987/88-1991/92. Biol. that a smallnumber of Grey Ploversmigrate along the Conserv. 77: 7-17. Mediterraneanflyway with stagingsites at the Black Sea Cramp, S. & Simmons, KE.L. 1983. The birds of the Western and CaspianSea area (Branson& Minton1976; Summers Palearctic. Vol. III, Oxford Univ. Press, Oxford. & Waltner 1979; Wymenga eta/. 1990). Birdswintering in Glutzvon Blotzheim,U.N., Bauer, K.M. & Bezzel, E. 1975: SouthAfrica are believedto migratevia the Great Circle Handbuchder VdgelMitteleuropas. Vol. 6/1, Wiesbaden. route (Summers& Waltner 1979). The recoveryof a bird ringedat the GermanBaltic coast in Egyptin itsfirst Kube,J. & Struwe,B. 1994. Die Ergebnisseder Limikolenz•h- wintergives further evidence that especiallyyoung birds lungenan der sOdwestlichenOstseek0ste 1991. Corax15, migrateon a wide front (col.Cramp & Simmons1983). Special Issue 2: 4-56. Meltofte,H. 1993. [Wadermigration through Denmark: populations, non-breedingphenology and migratory strategies.] Dansk CONCLUDING REMARKS Orn. Foren. Tidsskr.87: 1-180. (In Danish). Meltofte,H., Blew, J., Frikke,J., Rbsner, H.-U. & Smit, C.J. 1994. The restrictednumber of Germanrecoveries preclude Numbers and distribution of waterbirds in the Wadden Sea. detailedanalyses of the recoverypatterns and migration Results and evaluation of 36 simultaneous counts in the Dutch - German - Danish Wadden Sea 1980-1991. IWRB routes(e.g. age and sex specificanalyses, migration Publication34 / WaderStudy Group Bull. 74, SpecialIssue. patternsof differentpopulations, analyses of hardweather movementsetc.). The recoveriescorrespond well with North,P.M. 1987. Ringingrecovery analytical methods. Acta recoveriesfrom otherEuropean countries (c.f. Branson& Ornithologica23:1 - 175. Minton1976; Pienkowski& Evans 1984; Meltofte1993) as Perdeck,A.A. 1977. The analysisof ringingdata: pitfalls and well as withcount data. However,our presentknowledge prospects. Vogelwarte29: 33-44. aboutthe migrationpatterns of Grey Ploversis limited. Therefore,it seemsto be worthto carry out Pienkowski,M.W. & Evans,P.R. 1984. Migratorybehaviour of comprehensiveanalyses of the data storedin the EURING shorebirdsin the WesternPalearctic. In: Burger,J. & Olla, B.L. (eds). Behaviourof marineanimals. Vol. 6:92 - 103. data bank. About400 - 450 recoveriesare actuallystored Plenum Press, New York. there (Wassenaarpers. comm.). Prokosch,P. 1988. Das Schleswig-HolsteinischeWattenmeer als Fr0hjahrs-Aufenthaltsgebietarktischer Watvogelpopulationen am Beispielvon Kiebitzregenpfeifer(Pluvialis squatarola, L. ACKN OWLE DG EM ENTS 1758), Knutt(Calidris canutus, L. 1758) undPfuhlschnepfe (Limosalapponica, L. 1758). Corax 12: 273-442. W. Foken,Institut for Vogelforschungand U. Koeppen, ROsner,H.U., van Roomen,M., S0dbeck, P. & Rasmussen,L.M. VogelwarteHiddensee kindly provided the recoverydata. 1994. Migratorywaterbirds in the WaddenSea 1992/93. RinseWassenaar, Vogeltrekstation Arnhem provided the Wadden Sea EcosystemNo. 2, CommonWadden Sea number of recoveries stored in the EURING data bank. Secretariat& TrilateralMonitoring and AssessmentGroup, Wilhelmshaven.

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