SRJ10262Volume501

The region of the Slovenský kras Mts. is dominated by oak-hornbeam forests. Before the 1950’s, large parts of this land were deforested and grazed by sheep. In the present time, part of these areas was artifically forested and in some parts the area is being overgrown with a successionofscrubandwoods.Woodsproduceseedsthat arethebasicfoodcomponentofthemostabundantforest speciesA.flavicollis.MostpelletsamplesofS.alucofrom the Slovenský kras Mts. were classified as type A of the lowermountainrangeswithwarmeranddrierclimateand tosubtypeA1ofthecarsticregionswithhigherproportion of bats and the fat dormouse G.glis (Obuch 1992). Only in the hilly part of the Zádielská dolina valley, adjacent toVolovské vrchy Mts. with prevailing beech forests, we found a higher proportion of Limacidae (42.7%) in the

pellets of S. aluco and thus these areas were classified as type E.

On average the three main dietary types in the Slovenský kras Mts. contained 78.9% of Mammalia with twomaindominantspecies:A.flavicollis(28.3%)andM. arvalis(14.0%).Birds(Aves7.2%)arealsoquitefrequent. The frequency of lower vertebrate taxa (Amphibia, Reptilia and Pisces, 2.2%) is quite low. Evertebrata (11.8%) comprisemainlyoftheorderColeoptera(5.9%)andslug family Limacidae (5.7%).

FoodsamplesofS.alucofromtheJasovskýkrascarst are characteristic for the high proportion of six typical forest mammal species (Sorex araneus, S. minutus, C. glareolus, M. agrestis and Microtus subterraneus). The non-forest species M. arvalis is also quite frequent.

The samples of S. aluco pellets from the Zbojnícka jaskyňacavehaveshownbesidesbats(12.7%)thecompositiontypicalfortheAtypewithA.flavicollis(36%)being themostdominantprey,followedbyM.arvalis(12%)and C. glareolus (9%). Periodic increases in abundance of these species could be caused by population peaks. The following peaks were observed: A. flavicollis in 1995, 1997 and 2002, M. arvalis in 2006 and C. glareolus in 2008–2009.InSilickáľadnicacavetherewasanincreased proportionofA.flavicollis in2002,2005and2009–2010 andinLíščiadieracavein1997and2006.SimilarlyambiguousresultsassociatedwithrodentpeaksinS.alucodiet were found at four type E sites on the Muránska planina Mts. (Obuch 1997).

Silickáľadnicacave(Fig.4,Appendix2).In34years ofsamplingS.alucopelletswehavefound17batspecies with a presence of 4.7%. The garden dormouse Eliomys quercinus was more frequent in the first samples from 1976and1981andthenreappearedin2006.ThefrequencyofthemostdominantspeciesA.flavicollis(40.7%)was markedlybelowaverageatthebeginningoftheobserved period and above average in the last years (since 2002). In the last three pellet collections we could see increased frequencyoftheaccessorypreyitemssuchasC.glareolus andLimacidaefamily.Theoppositedevelopmentcouldbe seen in the non-forest species M. arvalis with frequency above average in the first three sampling sessions, when pasturesdominatedthesurroundingsofthecave.Between 1987 and 1997 the owl abandoned the cave. This was caused by the construction of a tourist trail and railing at the entrance to the cave.

Líščia diera cave (Appendix 3). The National Nature Reserve (NPR) Domické škrapy was deforested and grazed by sheep until the 1960’s. Presently this area is being overgrownwithshrubsandoak-hornbeamforest.Thediet of S. aluco whichwas scarcelypresentintheLíščiadiera cave was dominated by the non-forest species M. arvalis (35.7%).Othermammalpreyincludedmainlyforestspecies.BatspreferringwarmerclimatesuchasRhinolophus euryale and R. ferrumequinum were regularly present in thepellets.ThesespeciesarepresentinthecavesDomica and Čertova diera all year round (Uhrin et al. 2002a). The owl rested in the Líščia diera cave only for a short periodduringtheyearanditalsousedothersheltersinthe vicinity of the Domica cave, e. g. the chimney in the old building at the cave entrance.This building was repaired in2008andthereforetheowldisappearedfromtheLíščia diera cave during this period.The surrounding zone with adiameteroftwokmfromthiscaveislargelyforest-free. The diet of the owl inhabiting this cave is very close to

the samples from Sebeslavce, which were classified as subtype G1. The current vegetation succession in the surrounding of the cave Líščia diera cave is leading to an increase in forest species, while human influence is diminishing. Because of this development this cave was classified as typeA.

Maštaľná cave (Appendix 4).This cave at the eastern edge of Plešivecká planina plateau was inhabited by S. aluco during the whole Holocene period. The layers of the soil probe extracted at the entrance to the cave by Ložek & Horáček (1988) have shown changes in the frequency of different snail species (Gastropoda) and vertebrates(Vertebrata).Obuch(1998c)pointsatacertain time lag between the age of the snails falling in front of the cave entrance directly from the rock face above and theageofthebonesmovingfrominsidethecave,asowls inhabited deeper parts of the cave. In 1982 and 1994 we collected four samples of 0–5 cm surface layer of the soil from the sub-recent period in the deeper parts of the cave (samples1–4).SampleNo.1differsfromtherecentpellet samplesbyhigherfrequencyofthenon-forestspeciesM. musculus andA. microps. Sample No. 2 is distinct for the increasedfrequencyoffourpasseriformspeciesandslugs oftheLimacidaefamily.SamplesNo.3and4weredistinct for the non-forest species M.arvalis and C. leucodon. In the samples up until 1982, the non-forest species A. sylvaticus and A. agrarius were more frequent, whereas from the 1990’s the forest species A. flavicollis was more dominant. Even later the frequency of occurrence of the edibledormouseG.glisincreased.In1990’ssheepgrazing was stopped at the Plešivská planina plateau, followed by a strong succession of woods. The occurrence of the synanthropicspeciesM.musculus,Rattusnorvegicusand

P.domesticusaswellasfishinthefoodsamplesshowthat owlsfromtheupperedgeoftheplateauhuntinthevalley of the Slaná River and in the village Slavec.

RevúckavrchovinaMts.(Table4)ThismountainrangehassimilarenvironmentalconditionsastheSlovenský krasMts.Thecarsticareasaresmaller(Drienčanskýkras Karst). Caves and gaps with large entrances suitable as diurnal rest places for owls are absent. In large parts of this area, the geological ground is formed of igneous rock.DiurnalrestplacesofS.alucocouldbefoundinthe entrances to old mines after iron ore mining had ceased (Nandraž), magnezite mines (Jelšava) or andezite rock mines(Pokoradz).OthersamplesofS.alucopelletswere collected in buildings: in a granary (Hrušov), churches (Prihradzany,Španiepole),andcastle(NižnéValice),barn (Teplý Vrch) or from the lofts of abandoned buildings (Ratková, Hámor).

ThedietoffiveowlspeciesfromtheregionofRevúcka vrchovina Mts. was described in a separate study (Obuch 2000c).ThefoodremainsofS.alucofromthebuildingsare mainlycomposedofnon-forestspecies,classifiedastype G.InthechurchatPrihradzany,pelletsofbothS.alucoand T.albawerefound.Thedietaryrangesofbothspecieswere very similar without significant differences. The largest collection of pellets from the castle in Nižné Valice was distinct for its high content of bird remains, especially of the Parus and Passer genera and synanthropic mammal species such as M. musculus and R. norvegicus, but also non-forestspeciesofthegeneraApodemusandCrocidura and wetland species M. minutus and A. amphibius.

Theowlinhabitingthegranaryfilledwithgrainatthe edgeofthevillageHrušovconcentratedonhuntingforest mammal species, although the granary had a numerous population of house mice (M. musculus) and rats (R. norvegicus). This owl only used the granary as a diurnal roost place and searched for food in the forest.Therefore its food samples belong to the type A. Collections from the Hámor at Ratková are distinct for an increased proportionoffrogs(sp.R.temporaria)anddormice(species

M. avellanarius and G. glis).

Abandoned mine at Nandraž (Appendix 5, Fig. 5). In this mine, large summer colonies of R. euryale and Miniopterus schreibersii can be found and other bat species

use this cave during the winter (Uhrin et al. 2002b, c). The pellets of S. aluco contained eight bat species with 1.7% dominance, which means that the owl hunts them only occasionaly. Population lows of the main forest species A. flavicollis (47.9%) and C. glareolus (8.5%) are reflected in small samples and increased proportion of birds in the diet (2007) or greater abundance of frogs and invertebrates (2006).

Pokoradzské jazierka lakes (Appendix 6). The owl inhabiting the NPR Pokoradzské jazierka lakes showed a quite unusual specialization within the A type. In its pellets we could find seven frog species with 20.8% dominance. Its diet differed from the floodplain type

by the presence of R. temporaria and Limacidae family (2.2%) and dominance of A. flavicollis (31%). The most frequentfrogspeciesincludedRanacf.esculenta(13.8%) and Pelobates fuscus (4.1%). In recent years the size of the samples decreased due to the frequent disturbance of the owl, as this location is becoming a recreational area of the town Rimavská Sobota.

Cerová vrchovina Mts. and Bodvianska pahorkatina Mts. (Appendix 7). In the Cerová vrchovina Mts. we found the rest places of S. aluco in natural basalt massifs (Steblova skala, Pohanský vrch Mt. and Soví vrch Mt.), abandoned quarries (Ebeckého baňa mine under Ragáč Mt. and Šurice quarry at the Pohanský vrch Mt.). The

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Slovak Raptor Journal 2011, 5: 1–120. DOI: 10.2478/v10262-012-0057-8. © Raptor Protection of Slovakia (RPS)

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dietofS.alucointhisvolcanicmountainrangeischaracterized by highly dominant A. flavicollis (56.6%). The frequency of Aves (8.5%) was close to average for the dietary typeA, with only scarce occurrence of the family Limacidae (0.4%). The majority of the more numerous speciesshowedevendistributioninallcomparedsamples. Minor deviations from the mean were found in five species. In the Činča valley in the Bodvianska pahorkatina hills we found an owl’s diurnal rest place on the loft of alone standing cottage.

Type B from the middle montane zone. The middle montanezoneischaracterizedbydeciduousforests,with prevailing beech.The structure of S. aluco diet was close to the average for the whole area of Slovakia (Table 5). Therefore the B dietary type has no distinct determinate taxon. However, there are taxons that differentiate other dietary types from this average type. The main food componentsincludedMammalia(76.8%)withdominant species A. flavicollis (30.2%) and C. glareolus (14.2%).

Aves (5.4%) were a rare or accidental prey (at least of 56 species). The most dominant frog species was R. temporaria (7.8%), fish species Salmo trutta (0.3%) and most frequentinvertebrateswereoftheorderColeoptera(3.8%) and family Limacidae (5.5%). The comparison of food samplesfromsevenmountainrangesshowedthatthedominantspeciesA.flavicollishadaboveaverageabundance in volcanic mountain ranges and on the southern slopes of the Muránska planina Mts., where the subdominant species C. glareolus was also quite frequent. Further frequently occurring species showed higher abundances in the Veľká Fatra Mts.: S.araneus, M. avellanarius, G.glis, R.temporaria and the slug family Limacidae.The amount of material analyzed from the Malá Fatra Mts. and Strážovské vrchy Mts. was too small and thus could not be classified as this dietary type.

Veľká Fatra Mts. (Table 6). The majority of S. aluco food samples were collected from the rocky part of the mountains characterized by calcareous and dolomite bedrock. This ground is well drained and thus leads to

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Tab. 3. The diet of Strix aluco in Slovakia, Slovenský kras Mts., dietary types

Tab. 3. Potrava Strix aluco na Slovensku, Slovenský kras, typy potravy

diet )aluco Strix( owl tawny of diversity chronological and Spatial J: Obuch

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Tab. 3. continuation / pokračovanie