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Geobios 41 (2008) 79–90

Original article

Faunal and taphonomic analyses of a Late Pleistocene bird-boneassemblage from a cave deposit in north-west Hungary

Analyse taphonomique d’une accumulation d’ossements d’oiseaux duPléistocène récent provenant d’une grotte dans le

nord-ouest de la Hongrie

Erika GálInstitute of Archaeology, Hungarian Academy of Sciences, 49 Uri, 1014 Budapest, Hungary

Received 14 October 2005; accepted 27 June 2006

Available online 3 December 2007

Abstract

The paper presents a faunal and taphonomic discussion of the Late Pleistocene bird-bone assemblages excavated in Kálvária Cave no 4near the city of Tatabánya in north-west Hungary. A total of 1150 complete and fragmentary avian remains were recovered from twolocations on two separate occasions. Of these, 873 bones could be identified on the species-, family- or order-level. Fifteen of the identified19 bird taxa could be determined on the species level and they indicate a habitat typical of forest margins. Several species yielded juvenile orsubadult specimens, which in view of the breeding period means that these birds died during the summer, most probably between July andSeptember.

Each of the two assemblages had distinct characteristics. The high number of kestrel (Falco tinnunculus) long bones in Assemblage I generallyincluded complete skeletal parts from subadult birds, suggesting a colony which bred in the cave, whose chicks died of natural causes. Even thoughthe bones were exposed to a certain degree of water transport and soil corrosion, they were generally well preserved in the cave sediment. Size-characteristic analyses demonstrated that, in spite of the undeveloped morphological features, the sizes of limb bones usually corresponded to thoseof adult birds.

The greater part of the material in Assemblage II originated from a stratified deposit and was dominated by small and fragmented remains ofvarious taxa. The taxa which could be identified and the taphonomic features of the remains suggest that owl pellets formed the core of this boneassemblage.# 2007 Elsevier Masson SAS. All rights reserved.

Résumé

Cet article présente l’analyse faunique et taphonomique de plusieurs ensembles de restes d’oiseaux du Pléistocène récent, découverts dans lagrotte de Kálvária no 4, près de la ville de Tatabánya dans le nord-ouest de la Hongrie. Au total, 1150 restes aviaires entiers ou fragmentaires ontété récoltés dans deux secteurs différents et en deux occasions. Huit cent soixante-treize d’entre eux ont pu être déterminés taxinomiquement(ordre, famille ou espèce). Les quinze espèces identifiées indiquent un habitat typique des lisières de forêt. Plusieurs espèces ont fourni desindividus jeunes ou subadultes qui, compte tenu de la période de reproduction de ces oiseaux, ont dû décéder en été, probablement entre juillet etseptembre.

Les deux ensembles présentent des caractéristiques différentes. Dans l’Ensemble I, la grande quantité d’os longs du faucon crécerelle (Falcotinnunculus), incluant des parties squelettiques complètes d’individus subadultes, suggère l’existence d’une colonie nichant dans la grotte et dontles oisillons sont morts de causes naturelles. Même si les os montrent des traces de transport par l’eau et d’altération édaphique, ils sontgénéralement bien préservés. L’analyse biométrique montre que, bien que certains traits morphologiques soient peu développés, la taille des os desmembres correspond en général à celle d’oiseaux adultes.

E-mail address: gal_erika@yahoo.com.

0016-6995/$ – see front matter # 2007 Elsevier Masson SAS. All rights reserved.doi:10.1016/j.geobios.2006.06.005

E. Gál / Geobios 41 (2008) 79–9080

La plupart des vestiges de l’Ensemble II provient d’un dépôt stratifié et est dominée par des fragments de petite taille appartenant à des taxonsvariés. Les taxons identifiés et les caractéristiques taphonomiques des vestiges suggèrent que cet ensemble osseux est essentiellement formé depelotes de régurgitation de chouettes.# 2007 Elsevier Masson SAS. All rights reserved.

Keywords: Bird-bones; Cave deposit; Seasonality; Late Pleistocene; Hungary

Mots clés : Ossements d’oiseaux ; Dépôts en grotte ; Pléistocène récent ; Hongrie

1. Introduction

Kálvária Cave no 4 is a small rock shelter lying at the base ofKálvária Hill near the city of Tatabánya in north-west Hungary(Fig. 1). Bone remains from the cave debris were first collectedby György Vajna and András Tasnádi Kubacska in the early1970s (Assemblage I). The bones were identified by L. Kordos,who re-excavated the site in 1975 and collected bones from twoseparate locations (Assemblage II: Site 1 and 2). A cave debris,labelled Site 1 (probably identical with the location from whereAssemblage I was collected), yielded a small sample made upof small- and large-sized animals of various taxa. A niche with astratified deposit was found to the left of the cave’s entrance.This location was labelled Site 2 and it contained thousands ofbones of medium and small-sized animals (Fig. 2). Thedeposition of remains from this site is believed to be the resultof the water-transported concentration of small- and middle-sized skeletal parts from the assemblage of Site 1 (L. Kordos,personal communication). The results of the pollen analysesand of the studies on mammal bones and teeth have alreadybeen published (Kordos, 1994).

The Late Pleistocene deposit excavated at Kálvária Cave no

4 yielded one of the richest Quaternary avian materials fromHungary. The cave was not investigated previously and neitherhas a detailed report of the excavated material been published.The fossils in the two assemblages and sites were determined asbeing contemporaneous. The mammalian fauna was dominatedby Microtus arvalis, but remains of other vole species andsteppe elements were also well represented. The speciesidentified indicated that the fauna could be dated to 100–

110,000 years BP, falling into the Early Würm period.Palynological studies by H. Lorincz indicated the dominance

Fig. 1. Location of Kálvária Cave no 4.Fig. 1. Situation géographique de la grotte de Kálvária no 4.

of Pinus silvestris and P. cembra among the arboreal pollens.Genera of the Chenopodiaceae family, such as Artemisia andScabiosa, were highly represented among the non-arborealelements. Pollen data suggested declining temperatures and anincreasing aridity, leading to the formation of an extensive coldsteppe. Wet meadows were indicated by remains of Selaginellaand Alismataceae (Kordos, 1994). Archaeological artefactswere not found in this rock shelter. The aim of this paper is topresent a description and discussion of the avian material, withspecial emphasis on the taphonomic characteristics of the boneassemblages.

A number of works have dealt with the methodology andresults of taphonomic investigations made on vertebrateassemblages and on owl pellet in particular (e.g., Dodsonand Wexlar, 1979; Kusmer, 1990; Lyman, 1994; Lyman et al.,2003). Studies investigating cave deposits and owls as majortaphonomic agents responsible for cave faunas were alsopublished (e.g., Andrews, 1990). These works, however, aremostly based on the analyses of mammalian remains.

The taphonomic characteristics of avian bone assemblagesexcavated from cave deposits tend to be more complicated.Birds are more diverse in size and ecological preferences thanmammals. They may be taken to caves as prey items bymammals, including humans and by birds alike. Cave fissuresare also the natural habitat for a number of diurnaland nocturnal birds of prey as well as other avian species

Fig. 2. Sketch indicating the origins of material.Fig. 2. Schéma indiquant l’origine du matériel.

E. Gál / Geobios 41 (2008) 79–90 81

(e.g., corvids, swallows). Prey selection, hunting methodsand digestion considerably differ between owls and diurnalbirds of prey.

A number of quantitative and qualitative data pointing totaphonomic features left on avian skeletal parts by differentbirds of prey have recently been published. Some of thesepresent comparative data, concerning the patterns of pellets thatare regurgitated by different owl species (Bochenski, 1990,1997; Bochenski et al., 1993; Bochenski and Tomek, 1994),while others deal with the damage inflicted by diurnal birds ofprey (Bochenski et al., 1997, 1998). Direct comparisonsbetween owl pellets and food remains of diurnal raptors werealso made (Laroulandie, 2002). Other studies discussed fossiland subfossil bone assemblages partly or completely attributedto avian predators (e.g., Mourer-Chauviré, 1983; Laroulandie,2000; Lorenc, 2006). Data summarizing most of the results onrecent, subfossil and fossil bird-bone accumulations haverecently been published (Bochenski, 2005).

2. Material and methods

The Late Pleistocene bird-bone material from Kálvária Caveno 4 was surprisingly rich and well preserved. Major differencescould be noted between the bone accumulations from the twolocations. The complete bird-bone material excavated fromKálvária Cave no 4 consists of 1150 complete and fragmentaryremains. Of these, 873 bones were identifiable at least to theorder level. The total find material originates from twocollections and two sites.

Assemblage I contained 184 avian remains, of which 167were identifiable. Bird-bones in this assemblage were hand-collected (L. Kordos, personal communication). Assemblage IIcontained 966 avian bones in all. The finds from Site 1 in thelatter collection came to only 64 remains, of which 56 wereidentifiable. The rest of the assemblage was uncovered at Site 2.Four different layers could be distinguished at Site 2 and anadditional five levels were separated within Layer 3 (Kordos,1994). The entire deposit at this excavation was water-sieved.

The separation of age categories was based on the degree ofepiphyseal fusion of long bones. A high number of skeletalparts were intact and were thus, suitable for identification to thespecies level and for taking measurements. The identification ofremains was made using the reference bird-bone collectionshoused in the department of Geology and Palaeontology of theHungarian Natural History Museum and in the ZoologicalMuseum of the University of Copenhagen. Additionally, recentbones from certain species in Romania were also collected forcomparison. Measurements were taken with a digital calliper of0.1 mm precision following the international standard (von denDriesch, 1976). The taxonomic ordering follows Cramp (1998).

The examination of bones was made by light microscope.Hence, details on surface damage could not be determined andcompared with observed by SEM in the specialist literature(Bochenski and Tomek, 1997; Bochenski et al., 1997, 1998).Such kinds of analyses are essential in the study of caveassemblages because soil corrosion may produce taphonomicfeature similar to that of digestion in owls (Bochenski and

Tomek, 1997). Nevertheless, faunal studies as well asquantitative comparisons with the data available in theliterature were carried out to establish the origins of boneremains. A number of works written on the distribution, huntingand feeding habit, prey- and nesting-site selection of birds aswell as of some mammal species provided the biologicalbackground (Heltay, 1989; Andrews, 1990; Cramp, 1998).Quantitative taphonomic analyses included the frequency andfragmentation of skeletal elements, the proportion of the totalnumber of wing- to leg-bones (Bochenski, 2005) as well as theshare of bones from immature and adult birds and the generaltaxonomic distribution of the vertebrate remains excavated.

3. Results

Of the 1150 bird remains collected in the cave and during theexcavations, 873 bones were identifiable. A total of 19 aviantaxa could be identified: 15 to the species level, one to the genuslevel, two to the family level and one to the order level. Thespecies identified, as well as the number of identifiablespecimens (NISP), are presented in Table 1.

Assemblage I, containing a total of 167 bird-bones, wasdominated by kestrel (142 bones, 85%). The majority of thesebones came from subadult and juvenile birds. In addition tokestrel bones, two humeri came from a juvenile and adult quail(Coturnix coturnix). The remaining 23 remains could beassigned to small-sized, but fully grown perching birds(Passeriformes indet.).

Assemblage II contained a much higher number of bonesand species. The material excavated at Site 1 has much incommon with Assemblage I, except for the smaller number ofkestrel remains. It yielded one other species, barn swallow(Hirundo rustica), in addition to kestrel and quail. A significantproportion of kestrel bones belonged to immature birds at thissite as well.

Finally Site 2 in Assemblage II yielded the majority of avianmaterial, both as regards the number of remains and theidentifiable taxa. The richest levels in this respect were Layers2/3d (228 remains) and 2/4 (121 remains). The highest numberof bird species was recovered from Layer 2/3d: 13 of the 15species identified. The most frequent species in the sample fromSite 2 were quail, barn swallow, kestrel and partridge (Perdixperdix) (Table 1).

The species from Kálvária Cave no 4 belonged to middle-and small-sized birds. They can be assigned to six orders,namely Falconiformes, Galliformes, Gruiformes, Cuculi-formes, Caprimulgiformes and Passeriformes. The first fiveorders include only one or two species each. The majority oftaxa (13, that is, 69%) belong to six families of the perchingbirds: Alaudidae, Hirundinidae, Turdidae, Corvidae, Sturnidaeand Emberizidae.

4. Taphonomic features

As it was underlined in the section discussing methodol-ogies, analyses with scanning electron microscope were notcarried out on the material but the bones were carefully

Table 1Bird species and number of remains identified at Kálvária Cave no 4Tableau 1Espèces d’oiseaux et nombre de restes identifiés dans la grotte de Kálvária no 4

No. Taxa (English name) Assemblage I Assemblage II (site/layer) Total/taxa

1 2/1 2/3a 2/3b 2/3c 2/3d 2/3e 2/4

Cavedebris

Cavedebris

Muddyclay

Muddy and gravel layers Sandygravel

1 Falco tinnunculus (kestrel) 142 36 28 7 6 9 6 4 2382 Perdix perdix (partridge) 4 5 3 10 1 233 Coturnix coturnix (quail) 2 2 3 11 10 45 8 13 924 Crex crex (corncrake) 2 25 Cuculus canorus (cuckoo) 1 16 Caprimulgus europaeus (nightjar) 1 17 Galerida cristata (crested lark) 1 18 Lullula arborea (woodlark) 2 3 1 69 Alauda arvensis (skylark) 1 3 410 Hirundo rustica (barn swallow) 2 5 3 4 1 34 1 14 6411 Delichon urbica (house martin) 5 1 612 Turdus merula (blackbird) 13 1 1413 Pica pica (magpie) 2 214 Corvus monedula (jackdaw) 1 115 Corvidae indet. 1 1 216 Sturnus vulgaris (starling) 1 1 217 Carduelis sp. 5 518 Emberizidae indet. 1 119 Passeriformes indet. 23 16 12 25 56 31 111 45 87 400

Total bones/sites and layers 167 56 50 36 100 53 228 62 121

Taxa indicated in bold yielded bones of juvenile and/or subadult individuals.Les taxons figurés en gras ont fourni des individus jeunes et/ou subadultes.

E. Gál / Geobios 41 (2008) 79–9082

examined under a light microscope binocular. This offeredseveral useful observations but no details on the surface anddamages. Distinctive morphological traits could be observed onthe bones of adult birds. The skeletal parts of juvenile andsubadult birds were undeveloped and partially ossified,respectively. Four species among the identified taxa included

Fig. 3. The ontogenetic distribution of skeletal parts in the best represented taxa.Fig. 3. Distribution ontogénétique (classes d’âge) des parties squelettiques pour le

bones of juvenile and subadult individuals. These were kestrel,partridge, quail and barn swallow. The remains of certainsubadult perching birds were also found, but they could not beidentified owing to the small-sized and undeveloped skeletalparts (Fig. 3). The abrasion of bones was smooth and morepronounced on undeveloped skeletons than in the case of adult

s taxons les mieux représentés.

Fig. 4. Smooth abrasion marks on skeletal parts of a subadult kestrel.Fig. 4. Légères traces d’abrasion sur les ossements d’un faucon crécerellesubadulte.

E. Gál / Geobios 41 (2008) 79–90 83

individuals (Fig. 4). It included scattered holes on the shafts andfrequent, sieve-like openings on the epiphyses (Fig. 5). Thesurface of the broken bones mostly looked rough and clear atthe resolution used in this case. None of the remains showedgnaw marks, beak impact or other features suggestive ofhunting marks left by any mammalian or avian predator.

The two assemblages originating from different excavationsdiffer not only in terms of taxonomic composition, but also asregards the deposition and preservation of bones. The remainsin Assemblage I were mostly made up by the long bones ofkestrel and only 25 remains belonged to small-sized quail andperching birds. Skeletal parts of kestrel included limb elements,such as humeri, ulnae and radii, carpometacarpi, femora,tibiotarsi and tarsometatarsi. The proportion of wing and legbones was very similar: 75 versus 67 remains. Tibiotarsi andhumeri were the most frequent remains (22% and 21%,respectively), while radii were the most underrepresented bones

Fig. 5. Distal ends of the undeveloped (left) and fully ossified (right) humerusof kestrel. The arrow indicates the strong corrosion at the end of the bone.Fig. 5. Extrémités distales d’humérus de faucon crécerelle : pièces en coursd’ossification et totalement ossifiées. La flèche indique la corrosion importanteau niveau de l’extrémité de l’os.

by only 6%. Small-sized as well as especially fragile skeletalparts such as crania, vertebrae and phalanges were absent(Fig. 6(1)). The degree of fragmentation was usually quite lowin Assemblage I. Out of the 141 long bones from kestrel only 60(42.6%) were fragmented (Table 2).

Assemblage II, recovered during a later excavation,contained remains from two locations. The finds from Site 1came from a context similar to Assemblage I, with the bonesexcavated from cave debris. The avian remains found at thislocation included more kestrel skeletons than other avianremains in this case as well. Still, fragile and small-sizedskeletal parts, such as scapulae and phalanges, were to be foundin this assemblage. Regardless of taxa, the majority of longbones were intact and complete. Kestrel remains mainlyrepresented not fully grown individuals, while other specieswere represented by fully ossified skeletons.

The material excavated at Site 2 contained a wealth of smallbones that came mainly from passerines. In addition, hundredsof bone and tooth remains of amphibians, reptiles and smallmammals were excavated from the stratified deposit in the caveniche (Kordos, 1994). The number of kestrel bones declinedtowards the bottom of the deposit but this species wasrepresented by more small-sized skeletal parts there (Fig. 6(2)).Similarly to the finds from Site 1, these remains were mostlyintact and originated from not fully developed birds.

The number of remains recovered from the different layersrange from 36 (Layer 2/3a) to 228 (Layer 2/3d). Except for thedeposit from Layer 2/1, still dominated by kestrel bones,the sample from this site was characterised by the highfrequency of remains from perching birds. All types ofskeletal parts, including the most delicate elements of the skull(e.g., premaxilla), sternum, pelvis and phalanges were found.

Generally speaking, the bone assemblage from Site 2indicated a tendency towards the increase of small-sized bonestoward the lower layers. Quite a few remains had blackish stainson them attributable to the magnesium dioxide contents of thesoil. The remains from lower levels showed a higher degree ofcorrosion.

5. The biometric characteristics of kestrel remains

Although the majority of kestrel bones were not fullyossified, their morphological features and dimensions sug-gested an age close to maturity. In order to test this hypothesis,the sizes of long bones were compared with the dimensions ofrecent and fully ossified kestrel skeletons housed in osteolo-gical collections in Hungary, Romania and Denmark. Thegreatest length of bones was plotted against the smallest widthof shaft and compared between the age categories of birdsexcavated at Kálvária Cave no 4 and the sexes of modernspecimens.

Humeri were one of the most frequent long bones in thefossil material; the assemblage included 13 intact specimens.All came from subadult individuals. The modern skeletons usedfor comparisons included five male and five female specimens.The sex of two further specimens was unknown. Thedimensions of modern bones showed a great variation and

Fig. 6. Distribution of kestrel skeletal parts from Assemblage I (1) and the pooled Assemblage I + Assemblage II (2).Fig. 6. Distribution des éléments squelettiques de faucon crécerelle dans l’Ensemble I (1) et dans l’Ensemble I + l’Ensemble II (2).

E. Gál / Geobios 41 (2008) 79–9084

that the sizes of the fossil remains tended to fall into the sizerange of males. However, two humeri showed similardimensions to the largest females (Fig. 7(1)). Radii representedthe least frequent bone type both in the total number of remainsand among unfragmented bones. Only subadult individualswere identified. Their dimensions were compared with the sizesof 11 modern bones. Ontogenetic development for fossil radiireflected a tendency towards an increase in length rather thanrobusticity (Fig. 7(2)). Ulnae were represented in the fossilmaterial by 15 complete bones including four adult and 11subadult specimens. Three adult and six subadult specimensshowed especially large dimensions, corresponding to those ofone single male among the modern reference specimens(Fig. 7(3)). Twelve complete carpometacarpi were found, threeof which were fully developed. The latter represented largesizes with a tendency towards an increase in length rather thanthe width of the second metacarpus. The dimensions of

Table 2NISP and percentage of whole and fragmented skeletal parts in the long bones froTableau 2Os longs de faucon crécerelle : nombre d’éléments déterminés (NISP) et pourcent

Bones (NISP) Assemblage I

Complete bone Fragments Percentage ocomplete bon

Coracoideum 0 0 0Scapula 0 0 0Humerus 13 16 44.8Ulna 15 9 62.5Radius 4 4 50.0Carpometacarpus 10 3 76.9Femur 14 5 73.6Tibiotarsus 15 16 48.3Tarsometatarsus 10 7 58.8

Total 81 60 57.4

subadult specimens fall within broad size ranges in the entiredata set (Fig. 7(4)).

Of the leg bones, femora and tibiotarsi accounted for thegreatest number of complete remains in the fossil materialrecovered from Kálvária Cave no 4. The dimensions of two adultand 13 subadult femora are shown in Fig. 7(5). These remainsrepresented various sizes, which covered the full size range ofmodern kestrel bones. Nevertheless, the subadult specimensshowed a tendency towards an increasing robusticity rather thanlength. All fossil tibiotarsi originated from subadult birds. Theirsizes represented the highest degree of homogeneity. Except foran individual showing extremely small measurements both inlength and width, all subadult remains had a similar length asadult specimens, but were more gracile (Fig. 7(6)). Finally,tarsometatarsi were represented by one adult and nine subadultspecimens. Both measured dimensions corresponded well withthe measurements of the modern reference material (Fig. 7(7)).

m kestrel

age des ossements entiers et fragmentaires

Assemblage I + Assemblage II

fe (%)

Complete bone Fragments Percentage ofcomplete bone (%)

2 1 66.60 7 0

13 18 41.915 20 44.4

5 6 45.412 7 63.117 9 65.316 22 42.111 11 50.0

91 101 45.0

Fig. 7. Greatest length (GL) plotted against the smallest width of shaft (SW) (the second metacarpal for carpometacarpus). KC4: Kálvária Cave no 4; sa: subadult;R: recent; ?: sex unknown.Fig. 7. Longueur maximale (GL) et largeur minimale (SW) (du deuxième métacarpien en carpométacarpe). KC4 : grotte de Kálvária no 4 ; sa : subadulte ; R : récent ;? : sexe inconnu.

E. Gál / Geobios 41 (2008) 79–90 85

6. Discussion

6.1. Taxonomic composition

The abundant and well-preserved avian assemblage exca-vated from the Kálvária Cave no 4 offered the possibility of acomprehensive study from the faunal, palaeogeographical andtaphonomic point of view. Of the 19 bird taxa, 15 could beidentified on the species level. These birds provide importantinformation regarding the environmental and climatic condi-tions of the studied region, as well as the brooding season. Thebird species identified can be assigned to three ecotypes.Kestrel, cuckoo (Cuculus canorus), woodlark (Lullula

arborea), blackbird (Turdus merula) and magpie (Pica pica)prefer forest margins and bushy meadows. The exception in thisgroup is the woodlark which broods in the field and nests in theshrub or in trees. Partridge, quail, corncrake (Crex crex),nightjar (Caprimulgus europaeus), crested lark (Galeridacristata) and skylark (Alauda arvensis) are species typical ofmore open habitats. They inhabit wet and/or dry fields andsand-hills. The nest is made on the ground, sometimes hidden inthe grass. Starling (Sturnus vulgaris) is found both in woodlandand open areas. It nests in hollows in trees or cliffs. The thirdgroup of birds, including barn swallow, house martin (Delichonurbica) and jackdaw (Corvus monedula), have adapted tohuman habitats. These species originally prefer open, often

E. Gál / Geobios 41 (2008) 79–9086

rocky areas, where they nest in rock cavities and in the hollowsof banks (swallows), on cliffs and rocky outcrops. Cavities incliffs and cliff ledges are also frequent nesting places for thekestrel (Cramp, 1998).

The majority of the species identified have been describedamong the bone samples from other Late Pleistocene depositsas well. House martin and blackbird, however, have beenreported from the Middle Pleistocene only, while nightjar andwoodlark are first identified from a Pleistocene site in Hungary(Jánossy, 1980). Most of the birds identified at the Kálvária sitewere widespread in Europe during the Ice Age. Nightjar,however, is a rare species in the fossil record from Europe andhas been found in a relatively few countries only, such asCroatia, Greece, Italy, Romania and the Ukraine (Tyrberg,1998).

6.2. Seasonal considerations

All of the aforementioned species belong to the breedingfauna of Hungary. Partridge, crested lark, magpie and jackdaware resident birds. The majority of these species are migratory.They usually arrive in Hungary in April and leave in October.Skylark is present in Hungary for a longer period of time, fromFebruary to November. Some birds, such as kestrel andblackbird, may over-winter when the cold season is mildenough (Peterson et al., 1977).

Four species among the identified taxa included bones ofjuvenile and subadult individuals. These were kestrel,partridge, quail and barn swallow. The subadult remains ofcertain perching birds were also found, but they could not bedetermined owing to the small-sized and undeveloped skeletalparts (Fig. 3).

Kestrel eggs hatch over May–July. The fledging period isabout 30 days and the chicks become independent one monthafter the fledging. In the case of partridge, the breeding seasonin Central Europe is from May to June. Chicks are capable ofprecocious flight after ca. 10–15 days. Quail breeds the juvenilefrom late April to early June. The fledging occurs in about 19days, but the hatchling can flutter off the ground at ca. 11 days.However, the chick becomes independent only after 30–50days. The hatch of young in the case of barn swallow is thelatest, between June and August. The fledging period lasts for20–22 days and juveniles become independent a few weekslater. Of the four species listed above, kestrel and barn swalloware nidicolous, that is the hatchlings are cared for and fed bytheir parents extensively. The two galliform species arenidifugous and the young become independent quite early(Cramp, 1998). Considering the characteristics mentioned here,most of bird species probably died in July and August.

6.3. Biometrics

The frequency of complete long bones from kestrel offeredthe possibility of metric comparison with modern specimensand follows their size variation. The sizes of morphologicallyundeveloped bones are very close and often even correspond tothe measurements of adults. Humeri and tarsometatarsi showed

a parallel increase in length and robusticity. Distal wing bones(radii, ulnae and carpometacarpi) as well as tibiotarsi, tended toincrease in length rather than in robusticity. Only femorashowed a relatively greater development in robusticity(Fig. 7(5)).

Considering the size of birds the species identified belong totwo groups. Passerines – excluding blackbird, magpie, jackdawand starling – as well as quail belong to small-sized birds thatare smaller than 20 cm in length. The rest of the species, small-and medium-sized birds, fall in the range of 20–35 cm.

6.4. Taphonomic interpretations

The analysis of taphonomic characteristics of Assemblage Iand Assemblage II as well as the attempt to state the possibleagent(s) responsible for the accumulation of this cave depositposed the greatest challenge in their study. Attempts were madeto examine the two assemblages separately and to attributethem to different taphonomic factors but no information andobservation supported this hypothesis.

Accumulation I and II were collected by different palaeontol-ogists and hence the excavation methods differed. Bird remainsfrom Accumulation I were hand-collected that would explain thegreater frequency of kestrel bones. Accumulation II was water-sieved both in the case of Site 1 and 2. This would explain thehigh number of remains as well as the frequency of small bonesand species including amphibians, reptiles, birds and micro-mammals at Site 2 (Table 2), but does not explain the similaritiesbetween the material from Site 1 and Accumulation I. Theseambiguities probably result from redeposition, which is aphenomenon frequently encountered in cave sites. Character-istics of the bird-bone material from both sites confirm theobservation by L. Kordos that the material was redeposited bywater transport. That is, the stratified deposit of Site 2 is made upby small- and medium-size finds washed out from Site 1.Consequently, Assemblage I and II are considered to have hadcommon origins from a taphonomic point of view.

The excavation methods used in the case of Assemblage II,as well as the quantitative data published on the rest of thevertebrate material (Kordos, 1994), advanced the presentinvestigations concerning the possible taphonomic agent(s).The overall results show that avian skeletal parts dominated inthe bone material by 27.6%. Even if we disregard the totalnumber of kestrel skeletal parts (96) bird-bones are still themost frequent by 26.3%. The avian assemblage is highlypredominated by small passerines (44%). Reptiles, frogs andvoles contributed to the bone collection by 17.8% to 13.3%,while the other vertebrate groups were represented by less than10% (Table 3).

The accumulation of bone deposits in caves can be ascribedto various factors, including carnivorous mammals, diurnalbirds of prey, owls as well as natural death.

A number of bones assigned to red fox (Vulpes vulpes),arctic fox (Alopex lagopus) and Mustelidae – associated withcave habitats – were identified from both collections inKálvária Cave no 4 (Kordos, 1994). Foxes mainly feed on voles,lemmings, rabbits and to a lesser degree on birds. Nevertheless,

Table 3Frequency of remains from different vertebrate groups identified from Site 1 and 2, Assemblage IITableau 3Ensemble II : fréquence des vestiges de différents groupes de vertébrés identifiés sur les Sites 1 et 2, Ensemble II

Vertebrate group Site 1 Site 2 Site 1 + Site 2

NISP Percentage (%) NISP Percentage (%) NISP Percentage (%)

Large mammals 7 3.6 0 0 7 0.2Mice 6 3.1 297 9.3 303 8.7Voles 25 12.8 441 13.8 466 13.3Gophers 13 6.7 285 8.9 298 8.5Rabbits, Hares 14 7.2 114 3.5 228 6.5Insectivores 4 2.0 58 1.8 62 1.8Bats 5 2.6 25 0.8 30 0.9Birds 64 32.8 902 28.2 966 27.6Reptiles 10 5.1 612 19.1 622 17.8Frogs, Toads 47 24.1 468 14.6 515 14.7

Total 195 100 3202 100 3497 100

E. Gál / Geobios 41 (2008) 79–90 87

analyses made on the food samples of red fox in Hungary showedthat mammals (and especially micromammals) were morefrequent in their stomach contents, but birds (mostly gamespecies) dominated in the food remains collected from the lair(Heltay, 1989). The high frequency of avian prey was noted in thediet of stoat (Mustela erminea) as well. However, owing to theirhunting methods, these mammals are characterised by producinga great degree of fragmentation in bones (foxes) or birds are onlypartially eaten (Mustelidae) (Andrews, 1990). I do not possessdata concerning the fragmentation of mammalian remains, butnone of the avian bones showed gnaw marks or other signs ofmammalian predation. Moreover, a considerable part of theassemblage was excellently preserved.

Many of the bone assemblages found in cave sites areattributed to birds of prey. Concentrated bone accumulationsare ascribed to owls as these birds have special feeding habits.Owls regularly cast species-characteristic pellets containing theindigestible parts of prey animals, such as bones, teeth, fur andfeather. Many diurnal birds of prey also emit pellets, butcontribute to bone accumulations by undigested food remainsas well. Some species, such as imperial eagle (Aquila heliaca)and golden eagle (A. chrysaetos), vultures and falcons(e.g., kestrel) nest on cliffs and thus, both their bones andbones of their own prey are both represented in fossil deposits.Nevertheless, the food remains of other species which do notbreed in caves, but nest or roost in trees, may also contribute toaccumulations in rock shelters by water transport.

After eliminating predatory mammals as responsible for theaccumulation of this avian assemblage, three possible sourceshave been hypothesized:

� n

atural breeding site of kestrel and its prey accumulatedaround the nest; � p ellets and uneaten food remains of other diurnal or nocturnal

birds of prey;

� th e combination of the previous factors.

Kestrels frequently nest on ledge on cliff and in colonies andtheir breeding areas are often used over successive years. The

breeding success indicates 87% of fledged young. The rest fallprey to predators and die. The kestrel hunts throughout the day,frequently late into the evening. Its distribution in varioushabitats including moorlands, grasslands, wetlands and forestfringes often depends on the mobility, choice of prey and nestsite. Kestrel is adaptable and opportunistic in its food.Nevertheless, it is adapted to hunting small terrestrial animalsby the characteristic hovering flight and scanning ground forprey. It also may make direct attack to prey in bushes and trees.Voles are its most preferred mammalian prey if available. Birdsusually take a second place, open-country passerines being themost frequent. Newly fledged birds in the summer are almostexclusively given to the chicks. Kestrel may also prey onsmaller waders and juveniles of larger birds such as ducks andpartridges, but it is capable of killing species up to size of anadult lapwing (Vanellus vanellus) and coot (Fulica atra).Kestrel also may be heavily dependent on lizards in the warmerparts of its range. These characteristics make the preycomposition of kestrel very similar to many species of owls(Cramp, 1998). Pellet analyses showed that the digestion in thisspecies is very efficient. Micromammals were mostlyrepresented by teeth. Bird remains tend to be totally digestedbut some larger prey was not eaten whole. Overall, a great lossof prey individuals was observed (Andrews, 1990).

The high degree of damage to bones is characteristic notonly to kestrel but also to other diurnal birds of prey. The shareof complete bones was below 30% in the pellets of imperialeagle and gyrfalcon (Falco rusticolus); (Bochenski, 2005). Inthe case of imperial eagle, the degree of fragmentation washigher than in owls and lower than in gyrfalcon. Nevertheless,there were significant differences between the pellets anduneaten food remains considering the survival of bones. Longbones from the latter often were better preserved than theircounterparts in owl pellets (Bochenski et al., 1997). Bones werealso heavily digested (80% of articular ends and nearly 100% ofbroken surfaces) in gyrfalcon (Bochenski et al., 1998). Damageto pigeon (Columba sp.) long bones in the uneaten food remainsof peregrine falcon showed that humeri (70.3%), carpometa-carpi (64.3%) and ulnae (55%) survived in the highest degree

E. Gál / Geobios 41 (2008) 79–9088

among the well represented skeletal parts. Beak impact wasobserved on one-third to half of the shoulder girdle and wingbones (Laroulandie, 2002).

The degree of fragmentation was studied on kestrel bonesin our assemblage (Table 3), since this is the most frequentand also the largest species identified. Its size (32–35 cm) issimilar to that of pigeons. Skeletal parts excavated fromAssemblage I are shown separately from the completedeposit in order to follow the breakup attributable toredeposition. Even so 45% of long bones remained intact, butthis value must have been greater in the primary assemblage.The best preserved bones among the well representedskeletal parts were the carpometacarpus and femur in bothcases.

These two bone types as well as ulna appeared to be the bestpreserved long bones in the uneaten food remains of imperialeagle only (Bochenski, 2005). Ulna was also the third bestrepresented skeletal part in Assemblage I (Table 3). Never-theless, the proportion of wing elements (humerus, ulna andcarpometacarpus) to leg bones (femur, tibiotarsus andtarsometatarsus) show notable differences between data fromreferences and our material under study. Leg bones were morefrequent than wing bones in the pellets of imperial eagle.Correspondingly, wing elements were more numerous than legbones in the uneaten food remains of the same species(Bochenski, 2005). Considering the kestrel bones excavatedfrom Kálvária Cave no 4, wing and leg bones were almostequally represented in Assemblage I and also in the pooledAssemblage I + Assemblage II (49.6% to 50.4% and 49.7% to50.3%, respectively).

Small to medium-sized mammals, birds and reptiles arecommon prey items of imperial eagle. In some places mostlybirds and especially young individuals are taken (Cramp,1998). In the material collected beneath six eyries of imperialeagles in the Ural Mountains, birds constituted over two thirdsof prey items. Corvids made up more than 70% of this birdcomponent. Kestrel remains were also recorded, but no small-sized passerines were identified from these samples (Bochenskiet al., 1997).

The general occurrence of bird-bones in cave deposits aswell as their fragmentation (30% to 60% complete bones)shows that most of these accumulations originate from thepellets of owls that lived in the cave (Bochenski, 2005; Lorenc,2006). Considering the location of Kálvária Cave no 4 and theage of the material, three species may be considered: eagle owl(Bubo bubo), tawny owl (Strix aluco) and little owl (Athenenoctua).

Eagle owl is the largest owl in the western Palaearctic. Itsdiet is extremely varied, but mammals such as hares, voles,squirrels and birds – especially ducks and corvids – are the mostimportant prey. It frequently takes diurnal birds of prey andother owls. Amphibians, reptiles and fish are also eaten. Tawnyowl is a medium-sized owl whose diet is also diverse.Mammals, birds, amphibians and invertebrates are takenequally. As for little owl, birds up to the size of thrushes areusually hunted but some larger birds such as magpie andmoorhen (Gallinula chloropus) also occur in its diet. They are

mostly taken from roost sites, nests and nest broad. A largerange of frogs and toads, reptiles as well as mammals from thesize of mice to hedgehog (Erinaceus europeus) were alsorecorded as the prey of little owl (Cramp, 1998).

Patterns of bird-bone fragmentation in pellets of the firsttwo, larger owl species were published. These analyses showedsome clear differences in the preservation of bones:

� s

kulls and mandibles were rare in eagle owl pellets andfrequent in tawny owl pellets; � p roximal parts of tibiotarsus were more frequent in tawny owl

pellets, while distal parts in eagle owl pellets;

� b roken bones were more frequent in eagle owl than in tawny

owl;

� h umerus gave the best result for MNI calculations in tawny

owl, while tarsometatarsus was the best at the nest site ofeagle owl and humerus at non-nest sites (Bochenski et al.,1993).

There were no significant differences regarding the wing andleg bone ratio between the two species: these elements werecompletely or nearly equally represented (Bochenski, 2005).Additionally, it was found that bilateral beak impacts on thehumeri of avian prey were quite frequent in eagle owl pellets(Laroulandie, 2002). Analyses regarding bone damage left bylittle owl have not been carried so far.

Investigations on 23 bird-bone assemblages originatingfrom 10 Late Pleistocene (Vistulian) cave sites showed thatmost of the remains originated from eagle owl pellets (Lorenc,2006). Those fossil materials were compared with thecontemporary diet of this species. The results showed thatgalliforms or waterfowl predominated the assemblages.Raptors were usually represented by only a few remains.Among the passerines, corvids and thrushes occurred in thegreatest numbers.

7. Conclusions

The fossil deposits excavated in Kálvária Cave no 4represented one of the most abundant Late Pleistocene bird-bone accumulations from Hungary. The species identifiedindicate a habitat characteristic of forest margins. In view of thebreeding period of the bird species, that is, the presence ofjuvenile and subadult remains, most of these birds died duringthe summer. Although the majority of kestrel bones were notfully developed from a morphological point of view, thedimensions of many long bones were similar to those of adultbirds.

The observations made during the second excavation as wellas the taxonomic and bone size composition of the twoassemblages suggest that in Assemblage II, the stratifieddeposit at Site 2 resulted in the accumulation of the watertransported small- and medium-sized skeletal parts from Site 1.The strong similarities between the avian assemblages from thelatter and Assemblage I justifies this hypothesis on the one handand indicates that the different excavation methods did notconsiderably influence the final results on the other.

E. Gál / Geobios 41 (2008) 79–90 89

In spite of the numerous taphonomic studies made on thefood remains of various birds of prey, data regarding a numberof species are still missing. The composition of pellets anduneaten remains collected from recent urban areas as well frombirds kept in captivity makes comparisons with fossil materialsmore difficult. Analyses made by high resolution microscopeare essential in the recognition of the nature of the damage onthe surface of bones.

A number of taphonomic characteristics were consideredwhen attempting to identify the agent responsible for this avianassemblage. Mammalian predators and most of the diurnalbirds of prey were excluded because they produce a high degreeof fragmentation and damage on bones. In spite of a number ofsimilarities between the uneaten food remains of imperial eagleand the assemblage under study, this species was eliminateddue to the differences shown by the ratio of wing to leg bonesand avian prey composition, as well as the fact that imperialeagle rarely nests in cave sites.

Species composition in the recent diet and fossil pelletmaterials as well as the breakage of bones from larger preyanimals was also the reason why eagle owl seems an unlikelytaphonomic agent. It is also unlikely that tawny owl couldhave swallowed a number of birds similar to its own size and,additionally, the characteristics of the damage to avian bonesattributed to tawny owl do not meet the features of ourassemblage. Although many birds and small mammalsidentified from the Kálvária Cave fall in the prey size oflittle owl, a frequent inhabitant of caves, evidence for thispredator is missing as well. Nevertheless, the presence oflarger mammalian and avian skeletal parts in the deposit aswell as the lack of damage and fragmentation on the bonessuggest that an owl species may have contributed to theaccumulation.

The frequency of kestrel bones, their good preservation(including the lack of beak marks or related damage and around50% of complete bones), the comparable proportion of wingand leg elements as well as the great number of bones fromimmature birds all point to a kestrel colony that was nesting inthe rock shelter and birds that died by natural reasons. Kestrelalso could be responsible for the accumulation of voles and thebones of the smaller avian species such as quail, larks,blackbird and starling. The young birds of partridge may alsohave been taken by this species.

Apart from kestrel, barn swallow, house martin and jackdawcould also die of natural reasons as rock cracks and crevices arecharacteristic nesting places for these species.

Acknowledgements

I am grateful to L. Kordos for inviting me to work on thebird-bone material and providing information concerningthe excavations in Kálvária Cave no 4. I wish to thankM. Gasparik and A.B. Godfredsen for access to the bird-bonecollections of the Natural History Museum of Hungary andthe Zoological Museum in Copenhagen, respectively.Consultations with L. Bartosiewicz and E. Kessler were ofgreat help. I am grateful for the comments and suggestions

made by the reviewers – Z.M. Bochenski, J. Williams andan anonymous reviewer – that improved the quality of thepaper. L. Bartosiewicz and M. Seleanu revised the englishtext. J-M. Pétillon and C. Letourneux translated the frenchtext. This research was funded by the Domus HungaricaScientiarum et Artium Junior Fellowship of the HungarianAcademy of Sciences (2002), EC 5-Access to ResearchInfrastructure action of the Improving Human PotentialProgramme (COBICE, 2002), OTKA F048818 Grant andBolyai János Research Fellowship.

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