DATA ON THE MOLLUSC (MOLLUSCA) CONSUMPTION OF BIRDS IN THE DANUBE DELTA, ROMÁNIA. Botond J. Kiss-József Rékási & Andor Richnovszkyt.

Átírás

1 AQUILA VOL.: 102 (99-107) DATA ON THE MOLLUSC (MOLLUSCA) CONSUMPTION OF BIRDS IN THE DANUBE DELTA, ROMÁNIA Botond J. Kiss-József Rékási & Andor Richnovszkyt Abstract Kiss, J. B.-J. Rékási-A. Richnovszkyt (1995): Data on the mollusc (Mollusca) consumption of birds in the Danube Delta, Románia. Aquila, 102, p The stomach contents of birds collected in the Danube Delta behoeen showed that out of the 2154 specimens ofloo species examined, 422 individuals (20,39%) of 54 species had consumed molluscs. Above all, waterbirds had a considerable snail and bivalve consumption. Among the species in which more than 100 specimens were examined, 49,3%o of Mailard (Anas platyrhynchos), 5,1% of Pheasant (Phasianus colchicus), 43,6%> of Coot (Fulica atra), 4,7%, of Collared Dove (Streptopelia decaocto), 29,6%, of Hooded Crow (Corvus corone cornix) and 19,8%, of Magpie (Pica pica) has consumed molluscs. The most often consumed species were found to be Lithoglyphus naticoides, Bithynia tentaculata, Planorbis planorbis, Helicella obvia and Valvata piscinalis. Key words: molluscs, stomach contents, Románia. Introduction The objective of our research was to obtain a better picture of the mollusc consumption of birds as well as to collect data for a future study on the comparison of conditions in Románia and Hungary. In Hungary, the mollusc consumption of birds has been studied by Keve-Kleimer (1931, ), Keve (1955), Vásárhelyi (1957, 1960), Sterbetz (1973), Rékási-Richnovszky (1974), Bába (1975), Richnovszky (1975), Varga (1982), Sterbetz (1985), and Antonovics (1986). The study of snails also has significance for health issues, since domestic bird parasites spend certain stages of their life cyele in host animals, primarily snails. In order to learn more about the intermediate hosts, we need to know which snail species birds consume. The intermediate hosts of all Trematoda flukes and of numerous parasitic nematodes (Protostrongylidae, Trichiuridae, Filarioidae) are snails, while the eggs of bivalves develop into special larval stages termed glochidia, which live parasitically on the skin and gills of fish before completing their development in mud. Bivalves are also important indicators in relation to birds. For example, it is known that the absence or presence in large numbers of the Zebra Mussel (Dreissena polymorpha) affects con- 99

2 Kiss, J. B.-Rckási, J. & Richnovszky, A.f (1995) siderably the number of diving ducks and Coots in a given area. The literature from Románia on this subject is rather incomplete, there being only a few brief reports from the Danube Delta (Kiss-Rékási-Richnovszky- Sterbetz 1978, , 1986a, 1986b). No comprehensive study has yet been published. Material and methods We examined the stomach contents of birds shot or found dead. The thirty-two collection sites lie within, or in the immediate vicinity of the actual Danube Delta area which is förmed by the three branches of the River Danube. More than 70% of our matériái originates from the districts of Maliuc, Muri ghiol, Sarinasuf, Letea and Tul ea. The monthly distribution of birds collected was as follows: January 219, February 133, March 168, April 144, May 105, June 126, July 127, August 241, September 275, October 208, November 234, December 174. A total of 2154 specimens. Food remnants were stored and dried in paper bags. The molluscs were listed according to their decreasing frequency and total number found. A letter "x" indicates that the total number could not be definitely established. Table 1 shows the mollusc-consuming bird species listed in the systematic order of Keve (1984) with the number of specimens examined and the number and percentage of mollusc-consuming individuals. Table 2 shows the mollusc consumption of 54 bird species collected between With regard to the large number of species and specimens examined, negative results may also be of interest from the point of view of trophology. Table 3 lists the 46 bird species which were found to have not consumed molluscs. Results We examined the stomach contents of 2154 specimens of 100 bird species collected in the Danube Delta between individuals (20,9%) of 54 species (54,0%) had consumed molluscs. 52 mollusc species were identified from the prey items, somé of which could only be classified in a higher systematic category due to having been heavily digested. We concluded that mollusc consumption was not solely confined to strictly aquatic species. Smaller snail species are swallowed either attached to other food items or as gastroliths. Among the bird species of which more than 100 specimens were examined 49,3% of Mallards (Anas platyrhynchos), 5,1% of Pheasants (Phasianus colchicus), 43,6% of Coots 100

3 Data on the mollusc (Mollusca) consumption of birds. Table 1. Birds consuming molluscs in the Danube Delta between táblázat. A Duna-deltában közötti idó'szakban puhatestűeket fogyasztó madarak No. Bird species Total number of specimens examined Number Percentage of molluscconsuming of mollusc-consuming specimens specimens Sor Madár Összes vizsgált Puhatestűeket Puhatestűeket szám fajok egyedszám fogyasztók egyedszáma fogyasztók százalékos aránya 1. Podiceps grisegena ,0 2. Phalacrocorax carbo Ardea purpur ea ,6 15,7 4. Plegadis falcinellus ,0 5. Cygnus olor ,0 6. Anser anser ,3 7. Anas platyrhynchos ,3 8. Anas querquedula ,6 9. Anas crecca ,7 10. Anas acuta ,3 11. Anas elypeata ,0 12. Netta rufina 5 2" 40,0 13. Aythya fidigula ,6 14. Authya nyroca ,4 15. Mergus serrator ,0 16. Coturnix coturnix 8 1, 12,5 17. Phasianus colelúcus ,1 18. Rallus aquaticus ,3 19. Gallinula chloropus ,3 20. Fulica atra ,6 21. Haematopus ostraleg US ,0 22. Vanellus vanellus ,5 23. Pluvialis squatarola ,3 24. Charadrius alexandrinus ,0 25. Charadrinus morinellus ,0 26. Numenius arquata ,0 27. Limosa limosa ,1 28. Tringa totanus ,0 29. Tringa ochropus ,6 101

4 Kiss, ]. B.-Rckási, /. & Richnovszky, A.f (1995) Sor Madár- Összes vizsgált Puhatestűeket Puhatestűeket szám fajok egyedszám fogyasztók fogyasztók egyedszáma százalékos aránya 30. Actitis hyvoleucos ,0 31. Gallinago gallinago ,0 32. Scolopax rusticola ,0 33. Caliciris minuta ,0 34. Calidris alpina ,5 35. Philomachus pugnax ,6 36. Larus canus ,0 37. Stcrna hirundo ,1 38. Cokimba oenas ,2 39. Colámba palumbus ,5 40. Colámba livia ,6 41. Streptopelia turtur ,3 42. Streptopelia decaocto ,7 43. Strix aluco ,0 44. Coracias garrulus ,3 45. Melanocorypha calandra ,0 46. Alauda arvensis ,0 47. Corvus corone cornix ,6 48. Corvus frugilegus ,7 49. Corvus monedida ,0 50. Pica pica ,8 51. Turdus pilaris ,6 52. Turdus merula ,0 53. Erithacus rubecula ,0 54. Sturnus vulgaris ,2 No. Bird species Total number Number Percentage of of specimens molluscexamined consuming of mollusc-consuming specimens specimens (Fulica atra), 4,7% of Collared Doves (Streptopelia decaocto), 29,6% of Hooded Crows (Corvus c. cornix) and 19,8% of Magpies (Pica pica) were found to have consumed molluscs. The most frequently found mollusc species were: Lithoglypluts naticoides, Common Bithynia (Bithynia tentaculata), Ramshorn (Planorbis planorbis), Larger Sandhill Snail (Helicella obvia) and Common Valve Snail (Valvata piscinalis). 102

5 Data on the mollusc (Mollusca) consumption of birds. Table 2. Molluscs among the stomach contents of 54 bird species collected in the Danube Delta between táblázat. Az közötti idó'szakból a Duna-deltában gyűjtött 54 madárfaj puhatestű tápláléka No. Molluscs consumed No. of stomachs No. of specimens where present Sorszám Puhatestű táplálék Eset db 1. Mollusca sp Lithoglyphus naticoides Lamellibranchiata sp Indet. Mollusca sp. töredék 42 X 5. Bithynia tentaculata Planorbis planorbis Helicella obvia Valvata piscinalis Cardium sp Fagotia acicularis Helicopsis striata Gastropoda sp Vallonia pulchella Theodoxus danubialis Physa acuta Dreissena polyniorpha Chondrula tridens Viviparus sp Cepaca vindoboncnsis Theodoxus sp Viviparus contcctus Anisus septenigyratus Planorbis corneus Hydrobia stagnorum Monacha carthusiana Stagnicola palustris Valvata naticina Helix poniatia Perforatella rubiginosa Lymnaea stagnalis Viviparus acerosus Fagotia esperi Potamopyrgus jenkinsi Cochlicopa lubrica Planorbis spirorbis

6 Kiss, /. B.-Rékási, }. & Richnovszky, A.f (1995) No. Molluscs consumed No. of stomachs No. of specimens where present Sorszám Puhatestű táplálék Eset db 36. Pupilla muscorum Theodoxus fluviatilis Fagotia sp Unió pictonim Viviparus fasciatus Lymnaea peregra Mytilus sp Anisus vortex Gyraulus albus Lymnaea palustris Neritea sp Pecten sp Pisidium sp Planorbis sp Radix peregra Segmentina nitida Theodoxus transversalis 1 1 TöbZe 3. Bird species not found to have consumed molluscs in the Danube Delta between táblázat. A Duna-deltában közötti időszakban gyűjtött puhatestűeket nem fogyasztó madarak No. Bird species No. of specimens Sorszám Madárfajok Egyedszámuk l.gavia arctica 1 2. Podiceps nigricollis 2 3. Podiccps eristatus Phalacrocorax pygmaeus Ardeola ralloides 3 6. Egretta alba 1 7. Nycticorax nyeticorax 3 8. Ixobrychus minutus 1 9. Botaurus stellaris Anser albifrons Anas penelope Aythya ferina Circus cyaneus 1 104

7 Data on the mollusc (Mollusca) consumption of birds. No. Bird species No. of specimens Sorszám Madárfajok Egyedszámuk 14. Circus aeruginosus Falco subbuteo Perdix perdix Porzana porzana Arenaria interpres Lymnocryptes minimus Calidris alba C. temminckii Stercorarius parasiticus Larus cadiinnans Larus fuscus Larus ridibundus Larus ichtliyaetus Cldidonias hybrida Cldidonias niger Gelochelidon nilotica Sterna caspia Cuculus canorus Asio otus Alcedo attliis Merops apiaster Upupaepops Picus canus Dryocopus martius Dendrocopos maior Garrulus glandarius Parusis palustris Oenanthe oenanthe Coccothraustes coccothraustes Carduclis carduelis Carduelis ßanunea Fringilla coelebs Fringilla mon tifringilla 4 Total: 46 bird species Összesen: 46 madárfaj 138 specimens 138 egyed More interesting prey items found in large quantities in certain stomachs were 87 specimens of Bladder snail (Pliysia acuta), 53 Lithoglyplius natieoides, 50 Zebra Musseis (Dreissena polymorplia) - an indicator species - and 19 Fagotia acicularis. 105

8 Kiss, /. B.-Rékási, ]. & Richnovszky, A.f (1995) High mollusc consumption was found in Mallard, Tufted Duck (Aythya fuligula), Ferruginous Duck (Aytliya nyroca), Coot (Fulica atra) and Fieldfare (Turdus pilaris). It seems evident that snails are primarily a source of protein, their role as a supply of calcium is only secondary. Larger snails were unusual and when they did occur then it was invariably in the form of their tiny offspring. Smaller snails enter birds' stomachs attached to other food items or when being taken for pebbles. The X-ray examinations of Keve (1955) showed that shells have only a minor importance as gastroliths. Shell debris found by birds is primarily a source of calcium. Sterbetz (1985) found significantly more shell debris in the stomach contents of birds collected in the egg-laying period and during moult than during migration or in winter. This finding is supported by our results. Snail consumption is not season-dependent, it is the life style of birds that determines which species prey on molluscs. Irodalom - References Antonovits, D. (1986): Adatok Magyarországon gyűjtött madarak puhatestű táplálékáról. Soosiana, 14. p Bába, K. (1975): Csigákat fogyasztó gerincesek. Soosiana, 3. p Keve-Kleiner, A. (1936): A madarak csiga és kagylótápláléka. Aquila, p Keve-Kleiner, A. (1936): La consomation des mollusques per les Oiseaux. L'Oiseaux et la Revue Francaise d'ornithologie, 2. p Keve-Kleiner, A. (1937): Über die Conchylien-Aufnahme der Vögel. Comtes rendus du XII. Congr. Intern, de Zool., Lisbonne. p Keve, A. (1955): A madarak csigatápláléka, IV. Aquila, p , Keve, A. (1984): Magyarország madarainak névjegyzéke. Budapest, Akad. Kiadó, p Kiss, }. B.-Rékási, J. & Richnovszky, A. (1978): Romániában gyűjtött vadmadarak csigatápláléka. Soosiana, 6. p Kiss, /. B.-Rékási, ]. & Richnovszky, A. ( ): Dobrudzsában (Románia) gyűjtött vadmadarak puhatestű tápláléka. Soosiana, 10/11. p Kiss, J. B.-Rékási, J. & Sterbetz, I. (1985): Date noi privind hrana fazanului (Phasianus colchicus) in Delta Dunarii, I. p Kiss, J. B.-Rékási, }. & Richnovszky, A. (1986a): Molluscen als Vogelnahrung. Proc. of the 8th Intern. Malac. Congr. Budapest, p Kiss, /. B.-Rékási, J. & Richnovszky, A. (1986b): Die Untersuchung des Mageninhalts der im Donau-Delta gesammelten Vögel. Soosiana, 14. p Richnovszky, A. (1975): Az ártéri erdő puhatestű (Mollusca) faunája és annak szerepe a gerincesek táplálkozásában. Erdészeti és Faipari Egyetem, Erdőmérnöki Kar, Vadgazdálkodási Tanszék, Sopron. Egyetemi jegyzet, p

9 Data on tlw mollusc (Mollusca) consumption of birds. Sterbetz, I. (1973): Madártáplálkozási adatok a Balaton vidékről. Veszprém Megyei Múzeumok Közleményei, 12. p Sterbetz, I. (1985): Subfossilis Mollusca-maradványok Délkelet-Magyarország szikes tavain vizsgált vízimadár gyomortartalmakban. Puszta, 3/12. p Varga, A. (1982): Adatok a Streptopelia turtur csigafogyasztásához. Malakológiai Tájékoztató, 2. p Vásárhelyi, I. (1957): A dolmányos varjú csigafogyasztása és a gólya, mint a tógazdaság tisztogatója. Aquila, p Vásárlich/i, I. (1960): Csigákat fogyasztó gerincesek a Bükkben. Vertebrata Hungarica, II. 1. p Kiss János Botond Tulcea Of. p. 4. P. Box Románia Author's address: Dr. Rékási József Pannonhalma Vár u. 2. H-9090 Adatok a Duna-deltában (Románia) gyűjtött madarak puhatestű (Mollusca) táplálékához Kiss János Botond-Dr. Rékási József & Dr. Richnovszky Andort Összesen 100 madárfaj 2154 egyedének bromatológiai vizsgálatát végeztük el a Duna-deltában az közötti időszakban. A rendkívül ritka madárfajokra való tekintettel a negatív eredményeket is fontosnak tartottuk közölni. Puhatestű táplálékot (52 Mollusca fajt) 54 madárfaj 422 egyedében (20,93%) találtunk. A megvizsgált madarak közül: az Anas platyrhynchos 49,3%-a; a Phasianus colchicus 5,1 %-a; a Fulica atra 43,5%-a; a Streptopelia decaocto 4,7%-a; a Corvus corone cornix 29,6%-a; a Pica pica 19,8%-a fogyasztott puhatestűt. A leggyakrabban fogyasztott Mollusca fajok: Lythoglyphus naticoidcs, Bithynia tentaculata, Planorbis planorbis, Helicella obvia és a Valvata piscinalis. Különös fogyasztásként megemlíthetjük az egy-egy madárgyomorból származó nagyobb mennyiségű puhatestűt: a Physa acuta 37 példányát, a Lithoglyphus naticoidcs 53 példányát, a Dreissena polytnorpha 50 példányát és a Fagotia acicularis 19 példányát. A Duna-deltában vizsgált madarak puhatestű táplálékát egy későbbi tanulmányban összevethetjük a Magyarországon gyűjtött anyaggal. A madarak Mollusca-fogyasztása közegészségügyi jelentőséggel is bír. 107

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