A noteon Oystercatchersfrom the Varangerfjord,NE Norway R.H.D. Lambeck & E.G.J. Wessel Lambeck,R.H.D. & Wessel,E.G.J. 1993. A noteon Oystercatchers from the Varangerfjord,NE Norway.Wader Study Group Bull. 66: 74- 79. Biometricsof 11 breedingOystercatchers, caught during a visitto the northcoast of the Varangerfjord(NE Norway) from 27 Junethrough 1 July 1991, showed very short bills in both sexescompared to moresouthern populations. Incontrast, wing and tarsus tended to be somewhatlonger. Some further data are presented on breeding biology, mainly dealing with replacementclutches. The population ofthe north-Varangerfjord wasroughly estimated at 600 (sub)adults.Based on six recoveries plus an observation ofa colour-ringedbird, it ispostulated thatOystercatchers breeding west of North Cape-Porsangen migrate along the Norwegian coast andchiefly winter in Britain, while East-Finnmark birds fly over Lapland and along the Gulf of Bothniato a yet unknownwintering region on the 'continent'. R.H.D.Lainbeck & E.G.J.Wessel, Netherlands Institute of Ecology- Centrefor Estuarine and CoastalEcology. Vierstraat 28, 4401EA Yerseke,The Netherlands. Communicationnr. 591 of theCentre for Estuarine and Coastal Ecology, Yerseke. INTRODUCTION quantitativedata on the occurrence of Oystercatchersinthis area,b) to checkbirds for West-European colour-rings as an With40,000 pairs, as estimatedfor the 1970s (Kalas & easyway of obtaininginformation on migration,and c) to Byrkjeda11981),the Norwegianbreeding population of the (colour-)ringand measure local breeders. The inevitably OystercatcherHaematopus ostralegus isone of the largestin limitedresults, in combinationwith retrieved ringing data, are Europe(see also Piersma 1986). Detailedassessments made available in this note as a stimulus for further work. remaindifficult, however. The coastlineof Norway,so richin fjordsand islands, is extremely long (55,000 km; Kalas & STUDY AREA AND METHODS Byrkjeda11981),and large stretches are poorlyaccessible. Oystercatchersare nowadayscommon even around the TheVarangerfjord issituated in NE Finnmark,at about70 ø N upperends of fjord branches, over 100 kmaway from the and30 ø E (Figures1 and2). Fieldwork,carried out between opencoast. Increasedinland nesting (pers. obs.) further 27 Juneand 1 July1991, was limitedto the northerncoast of complicatesquantification. thefjord. A roadfollows the shorefrom the westernmost end at Varangerbotnup to the island-townVard•) in the east. In Giventhe lengthof thiscountry, which is situated between the general,the coastal hills gently slope into the sea. Between latitudesof 58ø and 71ø N, a geographicalpattern in biome- Varangerbotnand the town of VadsO(Figure 2) hayfieldsand tricsor migratorybehaviour cannot be excluded.Published meadowsare commonalong the shore,further east rocky informationabout measurements of Norwegianbirds is areaswith Empetrum heath predominate. The upper 7 kmof virtuallyabsent (cf. Glutz von Blotzheim etal. 1975;Cramp & thefjord is rathernarrow (1.5 km)with extensive mudflats Simmons1983). However,unpublished data should exist for especiallynear Varangerbotn. Tidal flats also occur near the a populationinthe southwest,near Stavanger. A few villageof Nessebyand some other places. The tidal range at hundredOystercatchers were ringed and measured here in Vads•)is about3 m. A moreextensive description of the area theearly 1980s (G. Toftin I/tt.).Little is knownof the birds is givenby e.g. Lessells& Leslie(1977) and Vaughan (1979). thatbreed at the otherend of the country,in thefar north.As A semi-quantitativedistribution map for Oystercatchers inthe an extensionof an expeditionto NW Russia(Lambeck et al. Varangerand the restof Finnmarkis providedby Frantzen et in prep.),a shortreconnaissance visit was therefore paid to al. (1991). theVarangedjord in NE Norway,an inletof the Barentsz Sea nearthe Russianborder. Aims were a) to collectsome Breedingbirds were caught at the nest,using drop cages and 74 type)was described according to Swennenet al. (1983). Birdswere provided with an individualcombination of one engraved16 mmhigh plastic colour-ring on eachleg, allowingfuture identification bytelescope. Chicks were caughtby handon the shore,and only supplied with a metal ring. Foreignring recoveries were obtained from EURING. Since thepreliminary account of Holgersen(1962), no overview has beenmade of recoveriesfrom Norwegian-ringed Oyster- catchers.Most of the ringing data from the Stavanger Ringing Centrecould be covered via the (bi-)annual 'Bird-ringing Reports,Stavanger Museum' (published by H. Holgersenup to 1981and O.J. Runde from 1981-1983 in Sterna) and a searchin the presentdatabase containing recoveries from 1986 (O.J.Runde, in litt.). Recoveriesfrom the former Oslo RingingCentre, responsible for 24% of the 3125 Oyster- catchersringed in Norwayup to 1975inclusive (Holgersen 1977),could only be traced up to 1974(cf. Anker- Nilssen et al. 1977). However,an additionalcheck for birdsringed in northernmostNorway could be madein the ForeignRing-files ofthe British, Dutch and German (only from 1987) Ringing Figure1. WestemEurope and the locationof the Varangedjord.Indicated Centres. are placesof ringingor recoveryof three Varangedjord Oystercatchers (&), and placesof ringing(n=3) of fourbirds recovered in the restof Rnnmark/ Tromsregion east of 21øE ( ß ); see alsoFigure 2, RESULTS AND DISCUSSION walk-incages, after replacement of the clutchby plasticeggs Breedingbiology forsafety reasons. Egg sizes were measured with calipers to the nearest0.1 mm. Bodyweight was determined on an Althoughone nest was found over 100 m fromthe water, local electronicbalance with an accuracyof 1 gram. Biometric Oystercatchersusually bred in the upperpart of the shoreline. parameters,viz. lengthsof bill,wing (maximum chord), Clutchsize in 11 nestsvaried between 1 and3 (twowith 1, tarsus+toe(all to the nearest1 mm)and tarsus only (to the twowith 2 andseven with 3 eggs). Includingalso two eggs nearest0.1 mm),were measured according standard pro- fromabandoned nests, the averagesize of the 29 eggswas cedures,and, additionally, the shape of the billtip (feeding 56.2 (ñ SD 2.1) x 39.7 (ñ SD 1.0) mm,with extremes of 59.6 18ø 21ø 24ø 27ø 30ø 33ø E Figure2. Theq'op ot Norway'with geographical names used in the text. Indicatedare recovery sites of four ringed Oystercatchers between the Varangedjord andthe 21øE meridian ( ß ), andthe placesof ringingor recovery(n=2) of threeVarangedjord birds ( & ). 75 Bill Populationsize Timewas too short for anydetailed census. Along 7 stretchesof the coastsearched between Ekker6y (11 kmeast 75 of Vads6)and Varangerbotn, comprising 7.4 kin,in total 17 territorialpairs, or 2.3 pairsper kin, were counted. The estimatedshore-length between Varangerbotn and Vard6 (includingVard6 and Vads6 islands and Ekker6y peninsula) is 7O 140 kin. Becausethe North-Varangercoast is hardly indentated,the realshore-length will not be muchlarger. Extrapolationwould then give a populationof 320 pairs.This 65 ß ß ß willbe an over-estimationbecause the easternpart of the ß coast,where densities were apparently lower (see also ß Frantzenetal. 1991),was not sampled. A crudeweighted calculation,assuming an average5 pairs/kmfor the first 10 6O kmfrom Varangerbotn, 2 pairs/kin for the nextstretch of 60 460 480 500 520 540 560 kmup to Ekker6y,and 0.5 pair/kmfor the final 70 kmto Weight Vard6,arrives at 205 territorialpairs. In 1977,9 pairsalong 4.5 kin,or 2 pairs/km,were counted around Nesseby (R6stad Figure3. Therelation between body weight (in g) andbill-length (in mm) for in litt.).Kalas & Byrkjedal(1981) used an estimated1 pair/km 11 breed•gVarangerfjord Oystercatchers. forthe entireNorth-Norway. Three small flocks of intotal 46 non-breederswere seen, all inadult plumage. Assuming this (x39.1) and (57.5 x) 37.0min. This average is nearly categoryto compriseabout one third of the population,as identicalto thatof eggscollected elsewhere in Norway foundon a Dutchisland (Ens 1992), would indicate a (Haftorn1971), and neither is it muchdifferent from figures for (sub-)adultpopulation size of over600 Oystercatchers. otherEuropean populations (see Glutz von Blotzheim etal. Duringour visit we already ascertained the presence of 184 1975). different individuals. We observedfive pairs with large chicks of overtwo weeks TheBarentsz Sea coast northwest of Vard6is very rugged (threewith 1, onewith 2, andone with 3 chicks),indicating an andexposed. Where the shore could be viewedfrom the 36 onsetof layingbetween 10 and15 May. Birdsnormally arrive kmlong road to Hamningberg,we saweight individuals, herein lateApril (Holgersen 1962). Onemore pair was seen includingat leasttwo territorial pairs, in shelteredbays only. witha chickof aboutthree days, and also an oneegg-clutch Biometrics wasnear hatching. On the other hand, several clutches had beenincubated for only two weeks and a threeegg-clutch foundon 1 Julywas even completely fresh. Considering the Besideseight chicks, 11 breedingadults were caught, advancedseason, the majoritywill have been replacement includingtwo pairs. The partners had clearly different clutches.Fresh storm tide marks and manypairs with only an bill-lengths(64 versus71, and65 versus77 mm,respec- emptynest-hole suggested that many clutches had been tively),the long-bills being the presumed females. One more washedaway in the preceding weeks. A similarphenomenon birdcould be reliablysexed as a femalefrom its brownish wasfound in the RussianBay of Kandalaksha(Lainbeck etal. backfeathers (cf. Cramp & Simmons1983). Thesample is