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 The majorityof the populationpasses detailson migrationpatterns by makingstill unpublished throughthe Wadden Sea again in autumn.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