SRJ10262Volume501

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Tab. 4. The diet of Strix aluco in Slovakia, Revúcka vrchovina Mts., types A and G

Tab. 4. Potrava Strix aluco na Slovensku, Revúcka vrchovina, typy A a G

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

Tab. 4. continuation / pokračovanie

3 – Ratková, Hámor, 1996–2002, 4 – Nandraž, gallery / štôlňa, 1997–2010, 5 – Jelšava, gallery / štôlňa, 7. 4. 2006 + 25. 3. 2007, 6 – Revúcka vrchovina Mts., other samples / ostatné zbary (Obuch 2000c), 2 – Hrušov, granary / sýpka, 1998–1999, 1 – Pokoradz, quarry / lom, 1997–2010, 9 – Prihradzany, church / kostol, 13. 11. 2002, 8 – Nižné Valice, manor house / kaštieľ, August 2001, leg. M. Uhrin & P. Benda, 7 – Teplý Vrch, Hikóriový porast, 1996–2007 + Španie Pole, church / kostol, 5. 6. 1995, leg. P. Benda

Other species (site – number) / Ostatné druhy (lokalita – počet):

Rhinolophus hipposideros (1–1), Myotis mystacinus (3–2; 4–3; 7–1), Myotis emarginatus (4–2; 5–1; 8–1), Myotis bechsteinii (3–2; 4–2; 5–1), Myotis blythii (1–1; 8–2), Myotis daubentonii (7–4), Vespertilio murinus (8–1), Eptesicus serotinus (2–1; 8–1), Nyctalus noctula (1–1; 7–1), Barbastella barbastellus (4–1), Plecotus auritus (4–1), Plecotus austriacus (1–1; 8–1), Dryomys nitedula (5–1), Microtus agrestis (3–2; 4–4; 2–2), Streptopelia decaocto (8–1), Strix aluco (6–1; 1–1), Dendrocopos major (7–1), Dendrocopos syriacus (2–1; 1–2), Dendrocopos medius (2–2), Dendrocopos leucotos (4–1), Dendrocopos minor (3–1), Jynx torquilla (1–1; 8–1), Alauda arvensis (8–1), Hirundo rustica (3–2; 4–1; 7–3), Riparia riparia (4–1; 7–1), Anthus trivialis (4–1; 1–2), Motacilla alba (3–1; 1–1), Motacilla cinerea (4–1), Bombycilla garrulus (3–1), Lanius collurio (3–4; 1–1), Acrocephalus palustris (7–1), Sylvia communis (7–1), Phylloscopus trochilus (5–1; 1–1; 8–2), Phylloscopus collybita (4–1; 8–4), Regulus sp. (2–1; 8–2), Sylviidae sp. (3–1; 5–1; 2–1), Ficedula parva (4–1), Ficedula sp. (1–1), Saxicola torquata (4–1), Oenanthe oenanthe (1–1), Phoenicurus ochruros (2–1; 8–4), Luscinia sp. (3–1), Turdus pilaris (1–1; 8–1), Turdus viscivorus (4–1; 7–1), Aegithalos caudatus (4–1), Periparus ater (3–2; 4–1; 5–1; 6–1), Lephopanes cristatus (8–1), Poecile palustris (4–2), Certhia sp. (2–2), Troglodytes troglodytes (4–1; 5–1; 1–1), Emberiza citrinella (3–2; 4–1; 1–2; 8–2), Emberiza schoeniclus (1–1), Fringilla montifringilla (4–2), Carduelis carduelis (4–1; 1–4; 8–3), Carduelis spinus (3–2; 4–2; 1–1), Carduelis cannabina (1–1; 8–1), Carduelis chloris (2–1; 8–4; 7–1), Pyrrhula pyrrhula (1–1), Serinus serinus (8–2), Oriolus oriolus (8–1), Garrulus glandarius (4–2; 6–2; 1–2; 8–1; 7–1), Passeriformes sp. (3–3; 4–1; 5–1; 6–1; 1–1; 8–1), Aves sp.juv. (4–1; 2–1; 1–1; 8–1),

Bombina sp. (1–1), Hyla arborea (4–1; 1–3; 8–1; 7–1), Rana ridibunda (1–4), Rana dalmatina (1–3), Rana arvalis (8–1), Lacerta agilis (1–1; 7–2), Lacerta vivipara (7–1), Diptera sp. (4–1), Lucanus cervus (4–1; 1–2), Gryllotalpa gryllotalpa (3–2; 2–2; 8–1; 7–1)

.8-0057-012-2478/v10262.10 DOI: .120–1 5: 2011, Journal Raptor Slovak (RPS) Slovakia of Protection Raptor ©

vicollis (50.3%) along with C. glareolus (17.2%). Part of the analyzed material came from nestboxes. K. Šottnár (in litt.) has found a relationship between the population peaks of these two forest rodent species and the nesting succes of S. aluco.

Volcanic mountain ranges of Central Slovakia (Appendix 13). Irregular sampling of S. aluco pellets from thevolcanicmountainrangesofCentralSlovakia:Kremnické vrchy Mts., Štiavnické vrchy Mts., Poľana Mts. and Veporské vrchy Mts. were distinct for their absence

of Limacidae and higher proportion of Aves (8.4%) and Coleoptera (6.4%). Therefore they were provisionally classified as type B. This large area requires a more detailed survey of S. aluco diet for final conclusion.

Type C from the higher mountain ranges and wet areas.HighermontanezoneandwetterareasofSlovakia are mostly covered with mixed conifer-decidous forests, or artifically planted monotypic conifer woods. The diet ofS.alucoinsuchconditions(Table8)usuallycontained

smaller proportion of rodents from the Muridae family, especiallyoftheforestspeciesA.flavicollis(10.1%).The M. avellanarius (10.2%) was highly dominant and we observed a more frequent occurrence of wetland species from the Arvicolidae family: M. agrestis (2.8%) and A. amphibius (2.4%). Birds (Aves, 6.7%) showed higher abundance than in type B; especially the proportion of thrushes (Turdus genus, 2.8%). Frogs were also rather dominant (R. temporaria, 24.2%). The invertebrate prey included numerous Coleoptera (4.2%) and Limacidae (5.3%).

The comparison of food ranges of S. aluco from different regional units revealed marked differences, which werereflectedinthenumberofdiagnosticspecies(Table 8).This was associated with different natural conditions, as well as different land use in individual regions: scatteredpeasantinhabitationintheKysuceregion,Wallachian deforestation in the past centuries and extensive planting of spruce in the 20th century. In the Horná Orava region, M. agrestis (18.3%) comprised the most dominant food component of S. aluco. In the Kysuce region, there was a high diversity of prey as seen from the high abundance of several passeriform birds (Aves, 17.8%). In several mountain ranges of Slovakia there were an increased proportion of insectivores (Insectivora), especially of

S. araneus and Talpa europaea.

Horná Orava region (Appendix 14). Most food samples of the S. aluco from this region were collected in nestboxes. The Horná Orava region is not based on geomorphology,butregionaldivision.Thedistributionof themorefrequentmammalspeciesinthesampleswasheterogeneous.WiththeexceptionofM.avellanarius,each dominant species was abundant only in a single sample: A.flavicollisinPekárkaunderBabiahoraMt.,S.betulina at Peciská, C. glareolus and M. agrestis in Tichá Valley underOsobitáMt.,S.araneusandA.amphibiusinBlatná dolina valley. These were all only small samples from a singleseason.Thereforewesupposethatinalongertime frame the influence of population peaks in the individual species on the composition of the owl’s diet will fade and regional influences will become more pronounced. M. agrestis and R. temporaria are the most frequent componentsofthediet.Invertebrates(Evertebrata1.3%) showed smaller abundance and the slugs (Limacidae) were missing.At the site No. 4 inAppendix 14 a sum of smaller samples can be seen, including a sample from RadovéskalyrocksunderOsobitáMt.,whereChionomys nivalis was found.

Kysuce region (Appendix 15). In the Kysuce region, food samples of S. aluco were collected in several geo-

morphological districts found in the Kysuce Protected LandscapeArea.Mostofthesampleswerefromnestboxes and nests in tree hollows from several nesting periods. In SkalitéandKlokočovwecouldfindthepelletsofS.aluco in the lofts of buildings in the centre of the village.These samples were distinct for their high proportion of synanthropicspeciesM.musculus,R.norvegicus,P.domesticus and the vole M. arvalis and therefore belong to subtype G2.Theinfluenceofscatteredpeasantinhabitationisquite apparent also in other samples, which were classified as type C. This is mainly reflected in high diversity of dietary ranges, because owls do not hunt only in the forest, but also in the fields, meadows and villages. In all these samples we could see non-forest mouse species such as A. agrarius (1.1%) and A. sylvaticus (1.4%). Half of all birds (Aves, 20.1%) are represented by thrushes (Turdus sp., 10.3%). Besides frogs (R. temporaria, 15.1%), no other prey species reach 10% dominance. Similar to the upper Orava region, in the Kysuce region the flysh geological ground causes the absence of slugs (Limacidae) and fat dormouse (G. glis), which are not represented in the diet of S. aluco.

ChočMts.(Appendix16).Incontrasttotheformertwo regions with flysh geological basis, the Choč Mountains arecharacterizedbylimestoneanddolomitealternations. The landcover is mainly formed of mixed conifer-deci- dous forests. A more detailed survey in the Choč massif wasconductedin1977–1978(Obuch1981).Fivesamples werecollectedatthesiteBieleBrehybelowPrednýChoč Mt. (No. 1–5). The oldest sample of detritus (No. 3) is characterized by a high dominance of R. temporaria and increased frequency of M. agrestis. Latter samples from 1989 and 2005 from this site are mostly dominated by

M. avellanarius and A. flavicollis. Temporal changes in the diet of S. aluco are described in a separate study (Obuch 1990). Owl pellets at Šíp Mt. and the Prašivá site below Choč Mt. were collected in 1996 after a marked population peak of A. flavicollis following a rich crop of beechnutintheautumnof1995.Appendix16showsonly food samples of type C. The sample from the the Válovy sitebelowPrednýChočMt.,whichwasdominatedbytwo species of bats, whas been placed in Table 9.

Nízke Tatry Mts. (Appendix 17). From the large area ofNízkeTatryMts.,wecouldonlyobtainS.aluco pellets from two sites. The food sample from the first location was dominated by frogs (R. temporaria, 61.5%). The sample from 1990 from the Okno cave was dominated bythecommonhousemartin(Delichonurbicum,22.1%), which were most probably hunted by the owl during their nocturnalrestonarockoverhang.Accordingtoarecover-

edornithologicalringthehousemartinswerenestingona blockofflatsinLiptovskýMikuláš.InthecloseZbojnícka jaskyňa cave a subfossile sample of S. aluco food was foundfromaperiodwhenDemänovskádolinavalleywas completelycoveredwithforests.Thefoodcompositionin the subrecent nest of the eagle owl (B. bubo) close to this cave,aswellasinthemiddleofJánskadolinavalleytestify tostrongdeforestationandgrazingduringtheWallachian colonization. In the 20th century both valleys were reforested mainly with spruce trees (Kučera et al. 2009).

SlovenskýrajMts.(Appendix18).Asubstantialpartof thefoodmaterialofS.alucotypeCfromtheSlovenskýraj Mts.camefromVýriajaskyňacaveinthePekliskogorge. In 1990, a sample of detritus from the about 20 year period when the owls inhabited the cave was collected. The most abundant prey items included frogs (R. temporaria, 43.5%).Another three samples from this site were domi-

nated by rodents (Rodentia). In this table we also present the sample from Poráčska dolina valley in the Volovské vrchy Mts. We also recorded two samples of type D with high proportion of bats. In 1990, fresh pellets of S. aluco werefoundattheentranceoftheDučacave.Thissitewas closetoatouristtrailonly200mfromtheentrancetothe Dobšiná ľadová jaskyňa cave. The owl abandoned this place most probably due to frequent human disturbance. BeforethediscoveryoftheStratenájaskyňacavein1972, the owl used to sit in a rock opening high in the cliff and its pellets would fall down the rock wall into the cave. After the new entrance was created, the owl abandoned thiscave.Besidesthisowl,batsinthecaveentrancezone were hunted by martens (Obuch 1995).

Type D: +Chiroptera. We suppose that the ability to specialize in hunting bats (Table 9) is only available to

some individuals of S. aluco which often encounter mass gatherings of this mammal order. There have been cases whenanowldwelledclosetoabatcolony,buthuntedthem onlymarginally(5%),e.g.insomecavesoftheSlovenský krasMts.orinthemineatNandraž.Therehavebeencases documented where an owl had hunted bats at a specific site in the past, but the next owl inhabiting the same cave did not (e. g. in the caves Erňa and Izbica). In Table 9 we present nine recent to subrecent samples with Chiroptera showinghigherdominancethan5%.Thesubfossilesample fromtheKrpcovocaveinVeľkáFatraMts.andSchaefer’s finding from the Muránska jaskyňa cave in the Belianske Tatry Mts. (Schaefer 1974) also fall into this category. The finding places of this dietary type of S. aluco were recorded in six mountain ranges at various altitudes. The rest of the prey belonged to typesA, B, C and E. The owl canhuntbatswhichrestinrockfissures(especiallyspecies

N. noctula, V. murinus, E. serotinus and P. pipistrellus

(Obuch 1994b)) or caves (winter or summer colonies) or in lofts.The samples from buildings where dominance of Chiroptera is >5% have not yet been classified as type D (loftsofthecastlesinTurčianskaŠtiavničkaandNecpaly, theparkinBanskáBystrica).Insomespaciouscavesthere isnoregularsummerorwinterbatcolonies,butbatssearch hereforprey.Anowlcapableofhuntingbatsinsuchplaces mayhaveagreatbatspeciesdiversityinitspellets,butthe dominance of bats as prey items will be low (e. g. Silická ľadnica cave, where we found 17 bat species with overall dominance only 4.7%).

ThehighdominanceofP.pipistrellusintheErňaand Ohnište caves is associated with an owl hunting them in their winter grounds. The bones at the entrance to the HýrovcanyonintheMaláFatraMts.werelocatedunder a rock chimney which was the diurnal roosting place of

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Tab. 7. Changes in food composition of mainly S. aluco in the Holocene samples from the Veľká Fatra Mts., Slovakia

Tab. 7. Zmeny v zložení potravy prevažne S. aluco v holocénnych vzorkách z Veľkej Fatry, Slovensko