RECENT DEVELOPMENTS IN THE GREYLAG GOOSE POPULATIONS IN THE EASTERN PART OF THE BALTIC BASIN

Transcription

1 RECENT DEVELOPMENTS IN THE GREYLAG GOOSE POPULATIONS IN THE EASTERN PART OF THE BALTIC BASIN The Greylag Goose (Anser anser) is a breeding bird connected with al1 the coastal areas of the Baltic Basin. In the preceding centuries it was widely distributed. However, in the course of the 19th century and during the first half of the 20th century it has disappeared from many places as a result of changes in the ecological conditions or due to disturbing by man. At the same time the Greylag Goose as a breeding bird has been related to two ecologically different habitat types - bays as well as coastal lakes rich in vegetation on the one hand and sea-islets on the other. This ecological specificity is even expressed by some vernacular goose names of several nations living on the Baltic seashore, such as merihanhi (Sea Goose - Finland) and roohani (Reed Goose - Estonia). In the eastern part of the Baltic Basin the present-day distribution of the Greylag Goose is confined to the following countnes (see HUDEC and ROOTH, 1970; SVENSSON, 1978; MERIKALLIO, 1958; von HAARTMAN et al., 1963; BERGMAN, 1969; KLAFS & ST~BS, 1977; TISCHLER, 1941; TOMIALOJC, 1976; ONNO, 1970; PAAKSPUU, 1974): In Sweden the Greylag Goose is distributed in the coastal areas of the Baltic Sea and of the Gulf of Bothnia, and locally in the interior of South Sweden (altogether 2000 breeding pairs at least - NILSSON, 1982). In Finland its distribution is confined to the territory along the coast of the Gulf of Bothnia and in particular to the archipelago in the south-western part of the country; the bird is rarely (about 20 pairs) found east of Helsinki on the shores of the Gulf of Finland. The total number of greylag geese in Finland may be estimated at pairs, the largest population of it ( breeding pairs) breeding in the north-western part of the Archipelago Sea (BERGMAN, 1969; BLOMQVIST and TENOWO, 1980). Up to 2000 pairs of the Greylag Goose breed in the German Democratic Republic, their overhelming majority inhabiting inland lakes. The nesting population of Mecklenburg alone is estimated at 1600 pairs. In Poland, like in the GDR, the nesting places of the Greylag Goose are located on inland lakes - its numbers are highest in the western part (near Milicza pairs, in the area round about Wielkopolska up to 100 pairs), in the Morag District of the Masurian lakes over 40 pairs. The total number of the Greylag Goose in lnstitute of Zoology and Botany. Academy of Scienoes of the Eslonian. S.S.R. SU TARTU, 21 Vanemuise Street. U.S.S.R. El Prof. Dr. Erik Kumari, sofio correspondiente de la S.E.O.. falleció el

2 28, ARDWLA Poland may be put at pairs at least. In Estonia the numbers of the Greylag Goose have by now increased to 800 pairs at least, two-third of the population breeding in protected areas (in the MatsaJu State Nature Reserve about 300 pairs). Amrding to A. S. MALCHEVSKY (in litt.), Anser anser breeds in South Karelia in small numbers, whereas in the Leningrad Region this species has become extinct in the last few decades. Summing up, the total number of the 'Greylag Goose as a breeding bird in the eastem part of the Baltic Basin may at present be estimated at about 6000 pairs. While the distribution of Anser anser in the southem part of the Baltic (the GDR and Poland) is chiefly confined to inland lakes, in Sweden and Finland the species occurs as a breeding bird of the coastal areas and sea-islands (in Sweden partly on inland waterbodies). In the last two or three decades the species has shown a tendency towards settling down also on Estonian sea-islands (AMEES, 1972; ONNO, 1972; PAAKS~, 1973,1974). The reasons for this trend probably are the much more peaceful living wnditions on the sea-islands (a large part of these islands are located in protected areas) than on lakes and coastal marshlands the drainage of which has been intensively tackled in the last few decades and which have come to be economically exploited. In the course of the last years the Greylag Goose has revealed a tendency to increase its nurnbers in the whole eastern part of the Baltic Basin and to occupy some areas which had been in the mean time left by it. The drift towards sea-islands in Estonia (as well as in Finland) need not be regarded as a new tendency in the distribution dynamics of the Greylag Goose but the restoration of its former distribution. The increase in the numbers of the Greylag Goose in the post-war years in the area under consideration is a general phenomenon which may be illustrated by a few instantes. The total number of the Greylag Goose in Estonia was in pairs, pairs, pairs, pairs, pairs (PAAKSPuu, 1974), at least 800 pairs. In 1957 a ban on hunting of the Greylag Goose was introduced in Estonia, whereas in 1969 a closed spnng season was proclaimed for al1 geese. Amrding to the statistics compiled by PAAKSPW (1973, 1974) of the 700 pairs of the Greylag Goose in Estonia in pairs (.e. 35% of the whole breeding population) inhabited sea-islands, 320 pairs inhabited bays rich in vegetation, 80 pairs lived on coastal lakes and 50 pairs - on marshalands and bogs. This species is disttibuted in East Baltic area only in West Estonia - in the region of the westem islands and in the continental coastal area, hence it is clearly a bird species with maritime distribution. The largest populations are located on the Matsalu (300 pairs) and Vilsandi (over 100 pairs) State Nature Reserves. The Matsalu State Nature Reserve is a wetland of intemational importance (size 48,634 ha), its eastern part comprise hugh reedbeds and extensive wet meadows (overfíooded in the spring and autumn), its western part - sea islets. In the Vilsandi State Nature Reserve the number of the Greylag Goose in 1959 were only 13 pairs, whereas in 1963 it was 72 pairs and in 1969 already pair (AUMEES, 1972). The Vilsandi State Nature Reserve

3 THE GREYLAG OOOSE IN THE BALTIC BASIN 29 (size 10,700 ha) is an entirely maritime area where the species nests only on seaislands. The distinct trend towards an increase in the population growth has revealed itself in the last ten years also in the archipelago of SW Finland (BuOMQVIST & TENOWO, 1980) and the territory of Poland's lake system (TOMIAuOJC, 1976). According to H~GSTROM (1971). in 1967 up to 125 pairs of Anser onser nested on the island of Gothland; lately, however, the numbers have considerably increased (at present about 300 pairs - ROLF BEINERT, in litf.). This is also favoured by the successful acclimatization of the Greylag Goose in some places in South Sweden (SVENSSON, 1978). The tirst nest of the species (TAURISNSH, in litf.) was found in Latvia in 1973, since 1977 the species has been met with already on several bodies of water (BAUMANIS & LIPSBERG, 1981). During the summer flocks made up of tens of non-nesting young birds and those adults whose breeding was a failure are often met with on the island of Hiiumaa pago) in the Kaina Bay (a relict coastal lake rich in vegetation) where at present 40 pairs of greylag geese breed; in August, however, there appear flights of birds amounting to 800 specimens (MANK& KALLAS, 1974). They stay there up to their departure in October or November feeding on wastal meadows and corníields. Tñe same phenomenon is observed in the Matsalu State Nature Reserve. After midsummer, a total number of over 3000 greylag geese migrate to the territory of the Nature Reserve in August and September, some flights mnning into 1000 specimens. At the same time they are observed in large numbers also on the islands of Saaremaa (Oesel) and Hiiumaa (Dago) (PAAKSPUU, 1972). At the end of August the numbers of such specimens (which obviously have arrived from far away) may exceed 8000 individuals. Similar phenomena are observed also on Gothland (KARIN JANSSON, in liti.), in the area of Mecklenburg (KLAFS and STOBS, 1977) and elsewhere. The population of the greylag geese of the Baltic Basin carries out extensive rnigratory movements also for moulting (KUMARI, 1979). Birds which have finished breeding on coastal lakes and in bays move into the region of lonely sea-islands 20 to 30 and more kilometres remote from the nesting places for the purpose of rearing their young and for moulting. Such a moult migration is observed in geese nesting in the inner reaches of the Matsalu Bay. Young geese reach their moulting places swimming in the course of 7 to 10 days resting in créche areas for several days. Such créche migration has developed in the geese of the Matsalu Bay evidently at the first decades of the century (PAAKSPUU, 1972, 1974), which was observed already in the 1930s by KUMARI (1937); this, however, has not been mentioned by earlier investigators. Adult birds are moulting in the same areas where the young grow up. In large moulting areas may congregate thousands of birds - on Gothland, for instance greylag geese (H~GsTROM, 1971; SVENSSON, 1978; v. BSEN & BEMERT, 1982). According to KLAFS and STOBS (1977), srnaller moulting places are found in the area of Mecklenburg near the shores of inland lakes; earlier coastal moulting places do not exist any longer. The larger part of the Mecklenburg geese,

4 however, pass to the ~traditionaln moulting places of Denmark and Gothland where large numbers of greylag geese obviously congregate from several par& of the Baltic Basin. After moult and restoration of flying large flocks of greylag geese appear in suitable areas of Mecklenburg in the second half of summer (August to early October); prior to fledging there may be staying up to 10,000 specimens. So large numbers are not observed either in Fennoskandia or in the eastem part of the Baltic area. According to PMKSPUU (1974) eleven moulting places of greylag geese recently were known to exist in Estonia, of them four are larger in area (accommodating 500á00 specimens everyone). Non-nesting geese apparently do not moult in Estonia, they fly outwards. Ringing has to a considerable degree wntnbuted to the establishment of the nurnbers and the seasonal distribution of greylag geese. The island of Gothland and the islets adjacent to it (Rone Ytterholme) have tumed out to be very good places for nnging. Since 1965 ROLF BEMERT (in litt.) has organized counting the moulting greylag geese here and catching them for nnging (in June and July). According to ~ ERLOF ( ), approximately 1000 greylag geese have been nnged in the interval of 19ó the number of recoveries having been 95. On the basis of these recoveries it has become evident that the graylag geese which moult on Gothland (and which come there from outside) start their migration in July (or August) chiefly across Denmark and the GDR, the larger part of them wintenng in Sapin (15 recovenes). A smaller part of them have Austria for their destination, chiefly the area of Neusiedlersee (6 recoveries). According to BERN~S (1966), ,000 greylag geese winter in Spain (Marismas del Guadalquivir), a larger part of them have Denmark as well as South Sweden and North Poland for their wuntry of origin. The birds start amving to their wintenng quarters in October and remain there to the end of February*. Of the 159 greylag geese nnged in Estonia (14 ad. and 145 pull.), 13 remveries have been made, of the latter 7 recoveries wnverge on the distnct of Neusiedlersee in Austria, the rest of the recovenes come from different places (2 of them from North Africa). Only one recovery has been made from Gothland (pull. ringed on 25th May 1963, captured on 2nd August 1964). From these data as well as from the results of ringing by Rolf Beinert one can conclude that very few Estonian greylag geese fly to Gothland for moult. The chief wintenng quarters of Estonian greylag geese seems to be Austria, like for part of the geese ringed on Gothland. According to the summary data of TIMMERMAN, MORZER BRUYNS and PHILLIWNA (1976), thousands of greylag geese winter round Marismas of Guadalquivir the maximum figures ranging between 10,000-25,000 specimens, * N. R.: The waterfowl wunts of the S.E.O. (ENA & PURROY. 1982) point out Ihe incmse of winterings - maximum of bitds in , so the demographic trends in he Spanish winter quanen ate a good evidence of Uie incrcase in the breeding grounds.

5 THE GREYLAG GOOSE IN THE BALiiC BASlN 31 hundreds of greylag geese winter in the distnct of Neusiedlersee, the maximum figure being 5,000 specimens. The population of greylag geese which have passed from the Baltic Basinio the wintering quarters belongs according to Scott's classification (1980) to the following division: «a population of about 40,000 birds breeding largely in Scandinavia and wintering in northwest continental Europe and Spain» (p. 17). To these should be added the greylag geese of Finland and Estonia. One per cent of this population of the Baltic Basin means 400 birds, in consequence of which a large part of the areas of the Baltic Basin frequented by greylag geese will have to be regarded as being of international importante. Acknowledgements. The author expreses his gratitude to those wlleagues who have put their oral or written information at his disposal for the writing of the present survey: Rolf Beinert (Visby, Gothland), Karin Jansson (Dalhem, Sweden), Taivo Kastepdd (Matsalu State Nature Reserve), Prof. A. S. Malchevsky (Leningrad), Valdur Paakspuu (Matsalu State -Nature Reserve) and Egon Taurinsh (Riga). SUMMARY In ihis papcr ihc demographical stalus ofgreylag Gwre (Anser ame,) in the eastern par1 ofthe Baliic Basin is rcviwd. An Incrcase of this specics dunne thc last decades is apprctiated The author estimata ihe population of this species in ihe siudied area lo be 6WO breedkg pain RESUMEN Crecimienro recienre de las pobluciones de Ansar Común en el Balrico Orienfal En este trabajo se revisa el estado demográfico de las poblaciones balticas de Ansar Común (Anser anser). En el se constata el incremento de la especie durante las Últimas dkadas. El autor estima en unas 6.W parejas a la población niditicante de esta espie en el área considerada. AUMEES, L. (1972). On the nesting of Greylag Goose on the sea islets of west coast of Saaremaa Island. Geese in fhe USSR. (Ed. por E. Kumari). Págs Tartu. BAUMANIS, J. A. & LIPSBERG, J. K. (1981). Changes in the bird fauna of Latvia during ihe last 15 yean. Theses oyfhe X Bulric Ornifhologicul Conference. Vol. l. Pags Riga. BERGMAN, G. (1969). LVInu~ja smrisromme. Helsinki. BERNls, F. (1966). Aves migradoras &&iras. Fasc. 2. Madrid. BwMQvrsr. R. & TENOWO, R. (1980). The nesting of the Greylag Goose (Anser anser) in the northwestern Archipelago Sea. Suomen Riüfa. 28: ESSEN. L. & BEMERT, R. (1982). Mouiting A. anser along the Gotland coast. Aquila. 89: HAAR~N, L. V.; H~LDEN. P.; LINKOLA, P.; SUOMALAINEN. P. & TENOWO. R. (ed.). (1963). Pohjolan linnur varikuvin. Vol. 1. Helsinki. Hffimd~. S. (1971). Ett Tórsok att faststalla storleken av den hackande stammen gragiss Anser anser pa Gotland. Var Fagelvarld. 30 (3): 201.

6 32 ARDWU HUDEC, K. & Room, J. (1970). Die Gragans. Die Nw Brehm-üücherei. Wittenberg Lutherstadt. KIAFS. G. & WJas, J. (1977). Die Vogelweir Mecklenburgs. Sena. Kmni, E. (1937). Maferials 10 ihe Avi/mmn o/ Mafsalu Bay. Tartu. -(1979). Moult and moult migration of wateñowl in Estonia. Wildfowl, 30: MANK. A. & KALLAS, J. (1974). Nesting bird fauna in Kiina Bay. Esioninn Weflnndr and fheir Life (Ed. por E. Kumari). Págs Tallinn. MERIULLIO, E. (1958). Finnish birds, their distribution and numbm. Fama Fenaico. 5: NILSSON. L. ( Det hackande araaasbestandets storlek och utbrednina - i Sverine. - De svmcka gas&. vor ~&elv irld, Supl. 9:-33->8. ~NNO. S. (1970). The numbcn and distribution of the Estonian waleifowl during the nesting stason. Waterfowl in Esfonia (Ed. por E. Kumari). Págs Tallinn. -(1972). Spread of the Greylag Goose on the sea islets of Estonia. Geese in fhe USSR (Ed. por E. Kumari). Págs Tartu. üsm~1.0~. S. ( ). Reoorrs for of rhe BirdRUt~Utp - Onice... 'iñe Swedish Muscum of ~atu&l ~istory. ~t&!&lm. - PAAKSPUU, V. (1972). Contemporary status of lhe Greylag Gwse ia Matsalu Bay. Geese Ut rhe por E. Kumari). Págs.: Tartu. - (1973). History ot the Greylag Gowe populaiion Ui West Estonia. Orn. Kogwnik, 6: M) (1974). ihe Greylag Goose in Estonia. Esronin Wellands and rheir Iife (Ed. por E. Kumari). Págs.: Tallinn. Scom, D. A. (1980). Apreliminary invenlory o/ weflandr ofinfemafio~l imporfme for waferfowl U, Wesf Europe and Norrhwesf Afiica. IWRB Spec. Publ. 2: WSSON, L. (1978). Swriges faglar. Stockholm. TIMMERMAN, A.; M~RZER BRWNS, M. F. & PHILIP~NA, H. (1976). Survey of the winter disvibution of palearctic geese in Europe, Watem Asia and Nonh Africa. Limosa. 49 (4): TISCHLER. F. (1941). Die Vogel Oscpreussens undseiner Nachkrgebiere. 2. Teilband. Konisgberg und Berlin. TOMIA~JC, L. (1976). Birdr of Poland. A Lis1 ofspecies and fheir disrriburion. Warsaw. [Recibido: j