Diet Composition of Syntopically Breeding Falcon Species Falco

Slovak Raptor Journal 2017, 11: 15–30. DOI: 10.1515/srj-2017-0006. © Raptor Protection ofSlovakia (RPS)

Diet composition of syntopically breeding falcon species Falco vespertinus and Falco tinnunculus in south-western Slovakia Zloženie potravy syntopicky hniezdiacich druhov sokolov Falco vespertinus a Falco tinnunculus na juhozápadnom Slovensku

Filip TULIS, Roman SLOBODNÍK, Vladimír LANGRAF, Michal Noga, Zuzana KRUMPÁLOVÁ, Zbyšek ŠUSTEK & Anton KRIŠTÍN

Abstract: The red-footed falcon and Eurasian falcon represent two syntopical falcon species. While the Eurasian falcon is considered a common and numerous species in Slovakia, the red-footed falcon population has undergone a considerable decline during the past few decades. Nowadays it nests in a single locality in Slovakia, the Sysľovské polia Special Protection Area, which forms the northern and fragmented border of the species distribution area in Europe. By analysing prey remains from 9 nests (from 1998, 2001, 2013, 2014 and 2016), we identified 433 prey items belonging to 35 taxa and 9 orders. Every year, invertebrates made up the major part of the diet spectrum, in which Calosoma auropunctatum, Tettigonia viridissima, Zabrus tenebrioides, Anisoplia aegetum and Rhizotrogus sp. were the most frequent species of prey. Of the vertebrates, Microtus arvalis was the most hunted prey species. By supplementary analysis of 21 photos, we extended our knowledge on the diet by other 6 taxa. The peak of the M. arvalis population growth in 2014 did not manifest itself in the red-footed falcon diet composition. In 1998, 2014 and 2016 we also studied the diet of a syntopical species, the Eurasian kestrel. By analysing prey remains in 22 nests, we identified 1,151 prey items belonging to 37 taxa and 7 orders. In 1998 and 2014 vertebrates predominated, especially the common vole, however in 2016 invertebrates prevailed. This fact could be a reaction to the M. arvalis population peak in 2014 and its decline in 2016. These results suggest that this variability in the foraging behaviour of the Eurasian kestrel, an opportunistic predator, during the hunting of invertebrates in- creases the diet similarity and overlapping of the food niche of both studied falcon species. Abstrakt: Sokol kobcovitý a sokol myšiar predstavujú dva syntopicky sa vyskytujúce druhy sokolov. Kým sokol myšiar je na Slovensku považovaný za bežný a početný druh, populácia sokola kobcovitého zaznamenala v posledných dekádach značný pokles. V súčasnosti tento druh hniezdi na Slovensku na jedinej lokalite – Chránenom vtáčom území Sysľovské polia, ktorá pred- stavuje severnú a fragmentovanú hranicu rozšírenia druhu v Európe. Analýzou potravných zvyškov z 9 hniezd (z rokov 1998, 2001, 2013, 2014 a 2016) sme tam determinovali 433 kusov koristi prislúchajúcich 35 taxónom a 9 radom. Bezstavovce tvorili každoročne majoritnú časť potravy, kde najčastejšie zastúpenými druhmi boli Calosoma auropunctatum, Tettigonia viridissima, Zabrus tenebrioides, Anisoplia segetum, Rhizotrogus sp. Zo stavovcov bol najčastejšie lovený druhom hraboš poľný. Doplnkovou analýzou 21 fotografií sme spektrum potravy rozšírili o ďalších 6 taxónov. Vrchol gradácie hraboša poľného v roku 2014 sa na zložení potravy sokola kobcovitého neprejavil. V rokoch 1998, 2014 a 2016 sme tiež sledovali potravu syntopického druhu – sokola myšiara. Analýzou potravných zvyškov 22 hniezd sme zistili 1151 zvyškov koristi, ktoré patrili 37 taxónom zo siedmych radov. V rokoch 1998 a 2014 v potrave dominovali stavovce, najmä hraboš poľný, v roku 2016 však prevažovali bezstavovce, čo môže byť reakciou na vrchol gradácie hraboša poľného v roku 2014 a pokles jeho populácie v 2016. Výsledky naznačujú, že táto variabilita potravného správania u oportunistického predátora sokola myšiara, lovom bezstavovcov zvyšuje podobnosť potravy i prekryv potravných ník oboch sledovaných druhov sokolov.

Key words: red-footed falcon, Eurasian kestrel, foraging, insectivory, central Europe

Filip Tulis, Vladimír Langraf, Zuzana Krumpálová, Department of Ecology and Environmental Sciences, Faculty of Natural Sciences, Constantine the Philosopher University in Nitra, Tr. A. Hlinku 1, 949 74, SK-949 01 Nitra, Slovakia. E-mail: [email protected] (corresponding author), [email protected], [email protected]. Roman Slobodník, Michal Noga, Raptor Protection of Slovakia, Kuklovská 5, SK-841 04, Bratislava, Slovakia. E-mail: slobod- [email protected], [email protected]. Zbyšek Šustek, Institute of Zoology, Slovak Academy of Sciences, Dúbravská cesta 9, SK-845 06 Bratislava, Slovakia. E-mail: [email protected]. Anton Krištín, Institute of Forest Ecology, Slovak Academy of Sciences, Štúrova 2, SK-960 53, Zvolen, Slovakia. E-mail: [email protected].

15 Tulis F, Slobodník R, LangrafV, Noga M, Krumpálová Z, Šustek Z & Krištín A: Diet composition of syntopically breeding falcon species Falco vespertinus and Falco tinnunculus in south-western Slovakia

Acknowledgment: We would like to thank J. Chavko and B. Maderič for collecting nest linings, J. Chavko for providing us with photos of the red-footed falcon with its food, J. Obuch for advising on the identification of vertebrates, M. Ambros for helping us in identifying Mammalia, and J. Kautman for helping us identify Amphibia from the photos. This research was carried out within the LIFE 11/NAT/HU/000926 project: Conservation of the Red-footed Falcon in the Carpathian Basin; A. Krištín was partially supported by VEGA grant No. 2/0097/16.

Introduction 2009). Around the Mediterranean and in Africa, insects Worldwide agriculture is one of the main factors influ- may even predominate (del Hoyo et al. 1994). In Slov- encing the general decline in biodiversity as well as bird akia the Eurasian kestrel diet has been studied mainly in species. Effective conservation strategies depend on the urban habitats (Darolová 1989, Kečkéšová & Noga type of relationship between biodiversity and land-use 2008, Mikula 2012, Mikula et al. 2013), where the pro- intensity, and on knowledge of foraging chains in this portion of vertebrates and invertebrates varies signific- system (Ursua et al. 2005, Kleijn et al. 2009). Raptors antly between localities and years. are top predators in agroecosystems, but their foraging The objectives of this study were therefore as fol- and food niches have been evaluated only partially lows: (i) to analyse the red-footed falcon diet in SW there. Many papers have focused on the diet composi- Slovakia in 1998, 2001, 2013, 2014 and 2016; (ii) to tion and foraging ecology of falcons, predominantly the compare the diet composition of red-footed falcons in myophagous Eurasian kestrel (Falco tinnunculus) (cf. different areas of its Pannonian population; (iii) to ana- review in Korpimäki 1985, 1986, Riegert et al. 2007, lyse the diet composition of syntopically breeding 2009). Less is known about the red-footed falcon (Falco Eurasian kestrels in 1998, 2014 and 2016; and (iv) to vespertinus) diet, where insects predominate and are compare the diet composition of red-footed falcons and sometimes substituted with small vertebrates (see re- Eurasian kestrels breeding at the same site and in the view in Szövényi 2015). There are differences however same years (1998, 2014 and 2016). in the importance of particular taxa in the diet of both species in different parts of their breeding range (Keve Material and methods & Szijj 1957, Riegert et al. 2007). Some of these differ- S t u d i e d s p e c i e s ences have natural character, e.g. site effect and habitat The red-footed falcon is a long-distance migratory spe- quality (Haraszthy et al. 1994, Purger 1998, Riegert et cies, staying in the Pannonian region from April to Oc- al. 2009, Szövényi 2015), or age of nestlings (Fülöp & tober (Cepák et al. 2008, Béltekiné et al. 2010). It Slivka 1988), while some others can result from differ- breeds mostly in colonies and occupies empty nests in ent methods of diet assessment (Tryjanowski et al. rookeries (Purger & Tepavcevic 1999, Purger 2001, 2003). We have only scarce data on the similarity of diet Lebedeva & Ermolaev 2012). It may also breed solitar- composition and trophic niches in congeneric falcon ily (i.e. individually), mainly in the nests of magpies or species living together in the same habitats, and in the rooks. In the last few decades it has also been known to same period. Furthermore, there is less knowledge on occupy man-made nestboxes (Béltekiné et al. 2010, inter-annual variability of the diet composition in the Kotymán et al. 2015, Slobodník et al. 2016). Whilst in red-footed falcon. Hungary the red-footed falcon population has grown The first data on the red-footed falcon diet from during the last 10 years (Béltekiné et al. 2010), in Slov- Slovakia were published by Balát & Bauer (1955), from akia and throughout most of its distribution range its the colony in Strekov (47°53.284' N, 18°25.602'E, Balát population has undergone a considerable decline during 1971), which does not exist anymore. Since that time recent decades (Palatitz et al. 2015, Slobodník et al. more relevant data on the variability of the red-footed 2014, 2016). The Sysľovské polia locality is not only falcon diet in Slovakia are lacking. Only preliminary the last breeding site in Slovakia, but it also represents reports on the red-footed falcon diet have been pub- its northernmost boundary of distribution in the Panno- lished in Slovakia (Tulis et al. 2016). nian region. Nowadays it is considered a Near The Eurasian kestrel is a vole-eating specialist in Threatened species (NT) in Europe and Vulnerable in northern and central Europe, but it is also able to con- EU 27 in the IUCN Red List (BirdLife International, sume other prey, such as bats, birds, lizards or insects 2016a), and listed in ANNEX I of the EC Birds Direct- (Korpimäki and Norrdahl 1991, Riegert et al 2007, ive 79/409/EEC.

16 Slovak Raptor Journal 2017, 11: 15–30. DOI: 10.1515/srj-2017-0006. © Raptor Protection ofSlovakia (RPS)

Fig. 1. Special protection Area Sysľovské polia. Study area with localisation of red-footed falcon and Eurasian kestrel nests. Obr. 1. Chránené vtáčie územie Sysľovské polia. Študijná plocha s lokalizáciou hniezd sokola kobcovitého a sokola myšiara.

Nowadays, the Eurasian kestrel is a mainly short- S t u d y a r e a distance migratory species in central Europe (Cepák et All the analysed samples of the red-footed falcon and al. 2008), and breeds solitarily (Horváth 1975, del Hoyo Eurasian kestrel diets were collected in the Sysľovské et al. 1994). It also occupies empty nests in rookeries polia Special Protection Area (SPA) (SW Slovakia, (Horváth 1975) and man-made nestboxes (Fargallo et 48°01´N, 17°06´E), which is the last known locality of al. 2001). Its population is numerous and stable, and in red-footed falcon breeding in Slovakia in the last six the IUCN Red List for Europe it is considered a Least years. The locality (of 1,776 hectares, see Karaska et al. Concern (LC, BirdLife International, 2016b). Its popu- 2015 for more details) is situated near the Danube, in lation density varies greatly between years, closely fol- the environs of the village of Rusovce at the Slovak- lowing the fluctuating spring densities of its main prey Austrian border. The foraging territories are composed (Village 1982, Korpimäki & Norrdahl 1991), namely of extensive high-yield fields with multiple windbreaks the common vole (Microtus arvalis). Characteristic for and farmyards on the Slovak side and heterogeneous this rodent population are the several-year fluctuation narrow small fields on the Austrian side (Fig. 1). The cycles in our environmental conditions (Jacob & windbreaks, in which the nests are located, consist of 30 Tkadlec 2010, Jacob et al. 2013). to 60 year old black locust (Robinia pseudoacacia), ash

17 Tulis F, Slobodník R, LangrafV, Noga M, Krumpálová Z, Šustek Z & Krištín A: Diet composition of syntopically breeding falcon species Falco vespertinus and Falco tinnunculus in south-western Slovakia

(Fraxinus sp.), common oak (Quercus robur) and tree Tab. 1. Characteristics of the analysed red-footed falcon and of heaven (Ailanthus altissima) with an overall length Eurasian kestrel nests from the Special Protection Area of 7.6 km in the locality. Sysľovské polia. Upper index = the same nest box / tree. Tab. 1. Charakteristika analyzovaných hniezdných výsteliek sokola kobcovitého a sokola myšiara z Chráneného vtáčieho F o o d a n a l y s e s a n d p r e y územia Sysľovské polia. Horný index = totožná búdka / i t e m s i d e n t i f i c a t i o n hniezdny strom. In five separate years (nesting seasons of 1998, 2001, nest box / year / nesting tree / height of 2013, 2014 and 2016) (collection months: Septem- nest / nesting (m) / ber–October) we processed 9 nest linings of red-footed búdka / rok hniezdny strom výška falcons and 22 nest linings of Eurasian kestrels from the hniezdo hniezdenia Sysľovské polia SPA (Tab. 1). The food remains were redfooted falcon nest box 1 998 Robinia pseudoacacia 8 hand-separated from the nest linings and put dry into nest box 1 998 R. pseudoacacia 7 PVC bags. Mammals were identified by means of the nest box 2001 Ailanthus altissima 9 key by Baláž et al. (2013). Birds, anurans and reptiles nest box 2001 R. pseudoacacia 9 nest box 201 3 R. pseudoacacia 5 were identified using reference collections to the spe- nest 201 4 8 cies level (except for Mus sp. because of the missing R. pseudoacacia nest box 201 4 R. pseudoacacia 7 identification characteristics). nest box 201 6 R. pseudoacacia 7 Invertebrates in food remnants were later identified nest box 201 6 Fraxinus sp. 6 using a microscope (Nikon) with 6–50x magnification. Eurasian kestler nest box 1 998 R. pseudoacacia 1 0 Each sample was processed on a Petri dish by separat- nest box 1 998 9 ing paired and unpaired prey body parts (e.g. heads, R. pseudoacacia nest box 1 998 R. pseudoacacia 7 mandibles, legs) to make an estimation of the numbers nest box 1 998 Fraxinus sp. 8 of individuals for each sample (Rosenberg & Cooper nest box 1 998 R. pseudoacacia 1 0 1990, Nuhlíčková et al. 2016). We identified food rem- nest box 1 998 Fraxinus sp. 9 nest box 1 998 Fraxinus sp. 8 nants to the highest possible accuracy of taxonomic nest box 1 998 sp. 7 level using a comparative collection of arthropods (cf. Fraxinus nest box 1 998 R. pseudoacacia 9 1 Pechacek & Krištín 2004). The prey items and prey nest box 201 4 Fraxinus sp. 7 2 sizes were identified according to Chinery (1987) and nest box 201 4 Fraxinus sp. 7 3 other references relevant to particular invertebrate nest box 201 4 R. pseudoacacia 7 1 nest box 201 6 Fraxinus sp. 1 2 groups (e.g. Giljarov 1964). The remnants of insects nest box 201 6 5 were identified in a similar way, with the numbers of R. pseudoacacia nest box 201 6 Fraxinus sp. 9 individuals based on unpaired body parts (head, pro- nest box 201 6 Fraxinus sp. 5 notum), paired organs (elytra divided by two) and leg nest box 201 6 R. pseudoacacia 4 1 parts (divided by six) nest box 201 6 Fraxinus sp. 5 1 nest box 201 6 Fraxinus sp. 7 Additionally, we also analysed 21 photos of a red- 2 nest box 201 6 Fraxinus sp. 7 footed falcon bringing its prey to the studied nests, 3 nest box 201 6 R. pseudoacacia 7 which it got from the locality of Sysľovské polia SPA in nest box 201 6 R. pseudoacacia 9 2007–2016.

S t a t i s t i c a l a n a l y s e s cimens from 47 nests) (Haraszthy et al. 1994) were Bearing in mind the different methods and times of ma- compared and estimated using the Jaccard dissimilarity terial collection, dissimilarities between the red-footed index. The species were then clustered using Ward’s falcon diet in Slovakia in particular years and also minimum variance clustering method to the Jaccard between the diet of red-footed falcons in Vojvodina dissimilarity matrix (Borcard et al. 2011). The validity from 1991 (locality in the vicinity of Melenci village, of the cluster results was evaluated using the cophenetic northern Serbia; sample size = 302 specimens from 4 correlation coefficient (Legendre & Legendre 1998, nests) (Purger 1998) and in Hungary from 1994 (local- Kreft & Jetz 2010), where K indicates the means clus- ity in the vicinity of Kunmadaras and Nagyiván villages tering optimization, which was used to determine the in the Hortobágy National Park; sample size = 764 spe- optimal number of classes. Analysis of similarities

18 Slovak Raptor Journal 2017, 11: 15–30. DOI: 10.1515/srj-2017-0006. © Raptor Protection ofSlovakia (RPS)

(ANOSIM) was used to test for statistically significant differences between groups of sampling units. The diet data of both falcon species were ln (x+1) transformed to suppress the influence of dominant taxa. Samples containing fewer than 3 individuals were ex- cluded from the analysis. Non-metric Multidimensional Scaling (NMDS; Cox & Cox, 2001) on Bray-Curtis dis- tances was used to visualize the patterns in diet composition of both falcon species in particular years. To run NMDS, the function “metaMDS” (“vegan” package) was used. Only taxa recorded in at least three samples were included in the analyses, and only taxa with a significant linear fit (“envifit” function) with the ordination (P < 0.05) were displayed in the resulting ordination diagram. Indexes of dissimilarity, cluster dissimilarity analyses and Non-metric Multidimensional Scaling analyses were imptlemented into R software v. 3.2.5 (R Core Team (2016), using the ‘vegan’ (Oksanen Fig. 2. Inter-annual differences in the relative abundance (mean et al. 2013) package. value ± SD) of diet groups (Orthoptera, Coleoptera and Verteb- rata, left Y-axis) and no. of taxa in diet (mean value; right Y-axis) Food niche overlap was measured with Pianka’s in- at the Special Protection Area Sysľovské polia (n = number of dex (Pianka 1973), where the index varies between 0 nests). (total separation) and 1 (total overlap). Obr. 2. Medziročné rozdiely v relatívnej abundancii (priemerná hodnota ± SD) skupín potravy (Orthoptera, Coleoptera Results a Veretebrata na ľavej osi Y) a počte taxónov koristi (priemerné hodnoty; na pravej osi Y) v Chránenom vtáčom území D i e t v a r i a b i l i t y i n r e d - Sysľovské polia (n = počet hniezd). f o o t e d f a l c o n n e s t s : i n t e r - a n n u a l a n d s i t e e f f e c t s By analysing 9 nest linings (in 5 years; 1998, 2001, of agricultural land with small fields) in 1991 (Purger 2014 and 2016 = two nests, 2013 = one nest) we recor- 1998) and from Hungary (foraging habitat composed of ded 433 prey items belonging to 35 taxa and 9 orders a close-to-nature puszta biotope covered with low (Tab. 2). Invertebrates (almost exclusively insects) ac- grasses) in 1994 (Haraszthy et al. 1994), three main counted for 76.2% of the overall diet, among which the clusters were created (Fig. 3). The first group involves most frequent species were Calosoma auropunctatum the diet of falcons in Slovakia from 1998, 2001, 2013 (27%), Tettigonia viridissima (11.8%), Zabrus and 2016 for which the presence ofApodemus sylvaticus tenebrioides (10.4%) and Anisoplia segetum (4.7%). and Calosoma auropunctatum was typical. In addition, Vertebrates accounted for 23.8%, among which mam- because of its size (length 20–30 mm, average dry mals predominated (22.6%). The most frequently weight 1.6 g, Šustek 1994, 2009), usually considerable hunted vertebrate was the common vole (M. arvalis) abundance in arable land (Varvara et al. 2010) and easy (18.5%). visibility, C. auropunctatum can represent even a con- Even in the inter-annual comparison of the diet siderable contribution to the food offer for the falcons. composition, invertebrates always prevailed over ver- In the second group, the analysis of dissimilarity singled tebrates (Fig. 2). Whilst in 1998, 2011, 2013 and 2016 out the red-footed falcon diet from Hungary in 1991, for the Coleoptera prevailed in the diet, in 2014 the share of which the occurrence of several species of insects (e.g. Orthoptera in the diet increased. Diet diversity varied, Agriotes lineatus, Gryllotalpa gryllotalpa, Geotrupes reaching the highest values in 2013 and 2016. mutator or Harpalus affinis) or anurans (Rana esculenta After evaluating the dissimilarity of the diet com- and Bufo bufo) was typical. The third group was composition from the large-sized fields in south-western posed of the red-footed falcon diet from Slovakia in Slovakia between the individual years and the diet of 2016 and from Vojvodina in 1991, in which the common the species from Vojvodina (foraging habitat composed vole was missing and in contrast the occurrence of

19 Tulis F, Slobodník R, LangrafV, Noga M, Krumpálová Z, Šustek Z & Krištín A: Diet composition of syntopically breeding falcon species Falco vespertinus and Falco tinnunculus in south-western Slovakia

Tab. 2. Diet composition of the red-footed falcon during 5 years in 9 nests at the Special Protection Area Sysľovské polia SPA, Slov- akia (n = number of prey items, g.sp. = unidentified genus and species, sp. = unidentified species). Tab. 2. Zloženie potravy sokola kobcovitého v 9 hniezdach v Chránenom vtáčom území Sysľovské polia, Slovensko, počas 5 rokov (n = počet objektov potravy, g.sp. = neurčený rod a druh, sp. = neurčený druh). breeding season / hniezdna sezóna 1998 2001 2013 2014 2016 ∑ taxa / food samples 1 2 3 4 5 6 7 8 9 n % taxón / vzorka potravy Invertebrates 330 76.2 Diplopoda Julus sp. 1 1 0.2 Odonata Odonata g.sp. 2 2 0.5 Orthoptera Tettigonia viridissima 4 3 1 5 1 4 1 3 11 51 11 .8 Platycleis veyselii 2 1 3 0.7 Decticus verrucivorus 5 3 1 9 2.1 Calliptamus italicus 1 1 4 7 1 3 2 1 9 4.4 Chorthippus oschei 2 2 0.5 Chorthippus sp. 6 6 1 .4 Stenobothrus sp. 1 1 0.2 Coleoptera Coleoptera g.sp. 2 2 0.5 Carabidae g.sp. 1 1 0.2 Zabrus tenebrioides 39 1 2 3 45 1 0.4 Pterostichus sp. 7 2 3 6 1 8 4.2 Calosoma auropunctatum 1 58 1 2 6 1 7 20 1 2 11 7 27.0 Cerambycidae g.sp. 1 1 0.2 Staphylinidae g.sp. 1 1 0.2 Scarabaeidae g.sp. 11 11 2.5 Cetonia aurata 1 0 1 0 2.3 Protaetia cuprea 4 4 0.9 Anisoplia segetum 1 2 1 1 0 5 2 21 4.8 Rhizotrogus sp. 3 3 0.7 Xylodrepa quadripunctata 1 1 0.2 Alleculides sp. 1 1 0.2 Mammalia 98 22.6 Rodentia Microtus arvalis 11 1 0 5 1 8 9 24 3 80 1 8.5 Apodemus sylvaticus 1 2 1 1 5 1 .2 Apodemus microps 1 1 0.2 Mus sp. 1 2 2 1 1 1 8 1 .8 Micromys minutus 1 1 0.2 Soricomorpha Crocidura leucodon 1 1 0.2 Crocidura suaveolens 2 2 0.5 Aves Passeriformes Sturnus vulgaris 1 1 0.2 Turdus merula 1 1 0.2 Passer domesticus 1 1 0.2 Reptilia Squamata Lacerta agilis 1 1 0.2 Amphibia Anura Pelobates fuscus 1 1 0.2 No. of taxa / počet taxónov 9 7 6 2 19 9 3 13 14 35 ∑ 61 83 26 7 86 65 3 62 40 433

20 Slovak Raptor Journal 2017, 11: 15–30. DOI: 10.1515/srj-2017-0006. © Raptor Protection ofSlovakia (RPS)

Tab. 3. Prey composition of red-footed falcons identified in 21 photos taken at the Special Protection Area Sysľovské polia in 2007–201 6 (* prey not found by food remains analysis in nests; g.sp. = unidentified genus and species, sp. = unidentified species). Tab. 3. Zloženie potravy sokola kobcovitého zistené z 21 foto- grafií z lokality Chránenom vtáčom území Sysľovské polia v rokoch 2007 – 201 6 (* druh koristi nebol zistený analýzou potravných zvyškov na hniezdach; g.sp. = neurčený rod a druh, sp. = neurčený druh).

taxa / taxón n Apodemus flavicollis* 1 Apodemus sylvaticus 1 Apodemus sp. 2 Microtus arvalis 3 Microtus sp. 5 Rodentia g.sp. 4 Gryllus campestris* 1 Hydrous piceus* 1 Lumbricus sp.* 1 Ruspolia nitidula* 1 Stetophyma grossum* 1

Clicelatta made up to 4.8% of the diet. With this method we extended the diet spectrum of the species in the locality of Sysľovské polia by 6 prey species (1 species of mammal, 4 insect species and 1 Clicelatta), which had not been identified by means of analysis of the nest linings. In total, with both these diet study methods we identified 42 prey species within 495 prey items of the red-footed falcon. Fig. 3. Dendrogram of the dissimilarities between the red- footed falcon diets in four years in Slovakia, in Vojvodina (Ser- bia) in 1 991 (Purger 1 998) and in Hungary in 1 994 (Haraszthy D i e t v a r i a b i l i t y o f t h e et al. 1 994). E u r a s i a n k e s t r e l : i n t e r - a n n u- Obr. 3. Dendrogram nepodobnosti zloženia potravy sokola kob- a l v a r i a b i l i t y covitého počas 4 rokoch na Slovensku, vo Vojvodine (Srbsko) v In analysing 22 nest linings (in 3 years: 1998 = 9 nests, roku 1 991 (Purger 1 998) a v Maďarsku v roku 1 994 (Haraszthy 2014 = 4 nests, 2016 = 10 nests) of the Eurasian kestrel, et al. 1 994). we recorded 1,151 items belonging to 37 taxa and 7 orders (Tab. 4). Vertebrates represented 56%, among which the mammals prevailed (53.8%). The common vole was the most frequently hunted mammal species Pterostichus sp. was typical. Among the individual with 51.4%. Invertebrates (though exclusively insects) groups of clusters we recorded significant differences in represented 44% of the diet. The most frequently and the diet dissimilarity (R = 0.97, P = 0.014). abundantly hunted taxa were Carabidae g.sp. (16.5%) and Curculionidae g.sp. (7.2%). D i e t o f r e d - f o o t e d f a l c o n s i n In the inter-annual comparisons we can see the pre- p h o t o s dominance of vertebrates over invertebrates during 1998 In analysing the photos, we identified 21 items of red- and 2014 (Fig. 5). In 2016 however we recorded a footed falcon prey belonging to 11 taxa and 3 classes change. There was then significant predominance of in- (Fig. 4). Mammals represented the most frequent class vertebrates over vertebrates, which showed itself in in- of prey (76.2 %), in case of insects it was 19%, and creased diet diversity.

21 Tulis F, Slobodník R, LangrafV, Noga M, Krumpálová Z, Šustek Z & Krištín A: Diet composition of syntopically breeding falcon species Falco vespertinus and Falco tinnunculus in south-western Slovakia 9 2 2 3 3 5 1 2 2 1 7 1 0 2 ...... % 5 0 0 0 4 6 0 0 0 0 3 0 1 7 4 1 ∑ 7 0 9 3 2 3 0 2 2 4 9 1 2 2 1 1 n 4 4 1 8 5 1 2 5 3 4 2 1 8 9 6 1 2 1 2 5 2 4 0 5 5 1 9 2 5 9 1 1 8 . . 1 6 2 2 . e l b 8 b a 1 1 9 2 1 1 a T 6 T 1 ď i e 0 v e 7 2 1 1 3 1 1 s – 1 , a d d n 6 n e 1 6 2 1 e g g e e L L . 5 1 . e 1 t a i i l s o a p 4 i 1 1 l 1 é o k p s é v 3 5 0 1 1 1 2 k o 1 1 1 1 ľ s s v y o ľ S 2 s 1 í 1 y m S e o 4 a z k 1 1 e 1 1 ú v 1 r 0 a A 2 m h n o C 0 č o i 1 J t 1 á t c v

Male red-footed falcon with hunted mouse ( e Fig. 4. Apodemus t o m 9 1 r sp.) (A) and common field-cricket ( ) (B) in o

Gryllus campestris P n l locality Sysľovské polia. e a n i 8 9 c á

Samec sokola kobcovitého s ulovenou ryšavkou ( r Obr. 4. Apo e h p

sp.) (A) a svrčkom poľným ( ) (B) na C demus Gryllus campestris S v 7 lokalite Sysľovské polia. e h 6 t 1 t 0 a 2 6 6 a 1 0 4 D i e t s o f F a l c o v e s p e r t i n u s 8 2 1 9 5 1 1 0 9 d 2 1

a n d F a l c o t i n n u n c u l u s i n t h e n a , 8 4 s a m e h a b i t a t 4 1 9 1 9 0

NMDS analysis of the diet dissimilarity of both studied 1 2 , v 3 1 1 8 falcon species revealed high similarity of the Eurasian o k 9 o 9 r

kestrel diets in 1998 and 2014. In that time it was Mi- 1 u 2 1 g h n i

crotus arvalis, Lacerta agilis and Anisoplia segetum e r b a u e i n 1 1 which influenced its diet. In 2016 Rhizotrogus sp. and d r l ó p s e z r u m

Pterostichus sp. influenced its diet, which was different v e t t u s s a s t a i l e r e a s a

in comparison with the other studied years. The red- t k a c a a l i u c n s . n r i s i n š a n m s d e r p i o y c u g

footed falcon diet evinced a constant similarity in 1998, a u z u i s d a e r s v . i c . l i . . p i e s s e m k s a l p i o i g d c p r p i c o a u i s 2013 and 2014. The diet of these samples was influ- a r r n d r a u s m . s t a / o i l n e e i r . i b u r u h g r z r s i o o h s s a g e a s / E e v v k o c e h

enced mainly by Tettigonia viridissima. In 2016 the red- u u d a l n i u v e c s o r p a h h n e a a e n p i s a e o t c c m s s s h o t i i n m o n t

footed falcon diet partially differed from the other stud- d t t i o a u m i u u a l s p s a o d t a o f s s d c r a v b b b r u a o s i u z p g o o o t r u i e s i a a a a c e e r r l e o e

ied years, in which Calliptamus italicus had an impact t t t r t c l l r r r l r i b e t t t s e e p p e e a o a a a a u s t t a n e i s o o o g T D C C C C C Z P P P C C on the diet composition. The red-footed falcon diet h e D P e h l n / t n . . i a r o t / 4 4 d shows small similarity with the diet of the Eurasian n c O C . . e a ó e b b e x x s r

kestrel across the studied years (Fig. 6). a a a a n b t t I T T

22 Slovak Raptor Journal 2017, 11: 15–30. DOI: 10.1515/srj-2017-0006. © Raptor Protection ofSlovakia (RPS) 0 . 8 1 8 5 1 6 8 2 2 8 4 2 3 1 0 2 3 1 1 8 3 2 2 2 3 3 1 1 ...... 0 . % 2 0 0 0 0 3 1 0 0 3 1 0 0 0 1 0 0 0 0 1 0 1 0 0 0 0 0 0 0 5 5 1 ∑ 1 9 2 2 1 1 3 4 7 5 1 1 9 6 1 2 2 1 9 2 3 1 2 4 1 3 3 2 2 3 3 1 1 n 1 3 4 2 1 1 3 1 6 5 1 2 4 2 4 3 3 2 0 1 1 1 1 2 1 5 1 2 1 1 1 1 2 1 2 2 2 0 8 5 2 1 9 0 6 1 1 0 1 8 2 2 5 1 9 7 0 3 1 1 1 1 1 1 1 1 1 9 8 3 4 4 0 1 2 1 2 1 1 1 1 1 2 1 6 6 1 0 7 6 2 6 1 2 8 1 1 6 7 5 7 1 1 7 1 3 5 5 6 1 2 2 4 1 1 2 4 5 2 2 9 1 9 7 1 2 2 3 3 7 5 1 4 1 3 1 1 1 1 1 1 4 1 1 2 1 3 1 3 1 6 6 4 7 0 9 1 1 1 1 2 1 1 9 1 1 1 9 0 1 2 0 0 1 8 3 1 1 1 9 9 1 3 1 9 8 8 2 1 2 7 9 1 9 2 3 6 1 2 1 1 8 2 6 9 5 1 1 5 1 1 9 1 5 9 4 1 1 1 5 1 1 8 3 1 1 8 5 1 7 1 2 5 2 1 1 4 1 1 a 7 n 1 1 8 4 1 2 0 6 1 ó z e s a s s t u i l u s a b s o d v n o n . u e e n e s o a r s n l c d p p i o s p i a n u e m t z s s o l a s . d o o p c ó o u a a e u e . . s i i g k s r u t i g i l o s n i t c v x r e v i i n p r p c c l a s l e c . s r i s s e s n t a l a / o e s g s a s y a s . u l a g s y u t e . n p u e t h a i z i u s a u s m t u g u l v n e a r e s e g e u l n t r i f / l s r v n m r e d m u g o s n i u s s v c u l u o e e g s i a a o a r s e o n a t a n a a a a e a u u v g i p č a a e v a a r n r r p a e a d m h a h i s i . o a o n t l o o t s m m a a m o u u d r p a r r a m m u p u i s i p s i b a a i t d p t r č t r p e u e e r d d r e e a n r o s n x x u i i a s a z d b o i o o a o a o / a n d d h e r s s a t i s e h c c c f r o t e e r e o r z t i e t s u o s i t t i r t i o o r r s s l t i a n c m b k c o o r t a o s u e a a i i u n e h o l r r l c o r n p p o o t a a l e n n o a o a o e s x a h i e a g l r c E S C P P A R O D M C A A M C C S S S P P A L P s h e a i C P i p t d a r s u n / n b . . a i i i o f o a m n l / 4 4 m d i n h o t R S P A A s . . e p a ó m . p e b b e x x a e o m v r a a a a T T b t t M A R A N ∑

23 Tulis F, Slobodník R, LangrafV, Noga M, Krumpálová Z, Šustek Z & Krištín A: Diet composition of syntopically breeding falcon species Falco vespertinus and Falco tinnunculus in south-western Slovakia

& Hölzinger 1969), Vojvodina (Purger 1998) or Hun- gary (Keve & Szijj 1957, Haraszthy et al. 1994). Szövényi (2015) also described the hunting technique of the red-footed falcon as being effective just for the hunting of insects. The predominance of two species of insects T. viridissima and C. auropunctatum together with the high representation of common vole (as the most frequently hunted vertebrate) in Slovakia suggests that the red-footed falcon gets the major part of its diet in agricultural land with enough trees and scattered green vegetation. Analysis of its foraging habitat selection has shown that the red-footed falcon prefers hunting in grasslands and fallow lands; it has a neutral attitude towards the alfalfa and cereal fields and it avoids hunting over intertilled crops, water surfaces, woods and artificial surfaces (Palatitz et al. 2011). The common vole in the natural conditions of Slov- akia is typical for population fluctuations of several years' duration (Jacob & Tkadlec 2010, Jacob et al. 2013). In our studied nesting locality, the Sysľovské polia SPA, growth in the population of the common vole culminated in summer 2014 (Krištín et al. 2017), Fig. 5. Inter-annual differences in the relative abundance (mean value ± SD) of prey groups (Orthoptera, Coleoptera and Verteb- however this culmination did not manifest itself in the rata in left Y-axis) and no. of prey taxa (mean value; right Y-ax- red-footed falcon diet, and we did not even record is) in Eurasian kestrel at the Special Protection Area Sysľovské a single instance of common vole in its diet in that year. polia (n = number of nests). By contrast, Bezzel & Hölzinger (1969) recorded an in- Obr. 5. Ročné zmeny v relatívnej abundancii (priemerná hodnota ± SD) skupín potravy (Orthoptera, Coleoptera a Vertebrata creased representation of common voles in the red- na ľavej osi Y) a počte taxónov koristi (priemerná hodnota; footed falcon diet just in the time of the culminating pravá os Y) sokola myšiara v Chránenom vtáčom území populations of common vole and field vole (Microtus Sysľovské polia (n = počet hniezd). agrestis). Vertebrates are commonly considered the minority part of the red-footed falcon diet (Balát & Bauer, 1955, Bezzel & Hölzinger 1969, Purger 1998, Pianka´s index shows relatively low overlapping of Haraszthy et al. 1994, Szövényi 2015, this study). Nev- the food niche between the two studied species in 1998 ertheless, short-term changes in the hunting strategy and (Pianka´s index = 0.32) and in 2014 (Pianka´s index = diet preference may occur, e.g. during cold and damp 0.33). However in 2016, we recorded an increase in the days when it was found that the red-footed falcon hunts food niche overlapping between both studied species common spadefoots (Pelobates fucscus) more, whilst (Pianka´s index = 0.67). during clear warm days the most frequent prey species were orthopterans (Horváth 1963, using direct observa- Discussion tions). Haraszthy et al. (1994) also recorded by direct F a c t o r s a f f e c t i n g p r e y v a r i- observation more long-term changes in the hunting a b i l i t y i n t h e c a s e o f t h e preference, when the common vole prevailed in the diet r e d - f o o t e d f a l c o n during a dry year whilst during the following wet and As we expected, invertebrates, especially insects, ac- rainy year it was the common spadefoot that prevailed. counted for the major part of the red-footed falcon diet The results of several other works based on direct ob- during the whole studied period. This is in accordance servation (Horváth 1964, Bezzel & Hölzinger 1969) not only with the known works from the territory of further suggest that vertebrates may play a more im- Slovakia (Balát & Bauer, 1955) but also with the rest of portant role in the red-footed falcon diet than is sugges- the species occurrence area, e.g. from Germany (Bezzel ted by the results of food remains and pellets analysis

Fig. 6. The NMDS ordination diagram showing Bray-Curtis dissimilarity between the diets of red-footed falcon and Eurasian kestrel during the studied years; square – diet of both Falcon species, circle – significant prey taxa (P < 0.05); (Fvesp_98 – Falco vesper tinus 1 998 etc., Ftinn_98 – Falco tinnunculus 1 998 etc.; T_vir – Tettigonia viridissima, C_ita – Calliptamus italicus, Cara_g.sp. - Car- abidae g.sp., S_vul – Sturnus vulgaris, Rhiz_g.sp., Rhizotrogus g.sp., Scar_g.sp. – Scarabaeidae g.sp., P_aer – Potosia aeruginosa, Cole_g.sp. – Coleoptera g.sp, L_agi – Lacerta agilis, Pter_sp. – Pterostichus sp., M_arv – Microtus arvalis, A_seg – An isoplia segetum. Obr. 6. NMDS ordinačný diagram zobrazujúci Bray-Curtisovu nepodobnosť potravy sokola kobcovitého a sokola myšiara; štvorec – potrava oboch druhov sokolov počas sledovaných rokov; krúžok – významný taxón koristi (P < 0.05); (Fvesp_98 – Falco vespertinus 1 998 atď., Ftinn_98 – Falco tinnunculus 1 998 atď.; T_vir – Tettigonia viridissima, C_ita – Calliptamus italicus, Cara_g.sp. – Carabid- ae g.sp., S_vul – Sturnus vulgaris, Rhiz_ sp – Rhizotrogus sp., Scar_g.sp. – Scarabaeidae g.sp., P_aer – Potosia aeruginosa, Cole_g.sp. – Coleoptera g.sp, L_agi – Lacerta agilis, Pter_sp. – Pterostichus sp., M_arv – Microtus arvalis, A_seg – Anisoplia se getum.

(Balát & Bauer, 1955, Purger 1998, our study). Horváth the central part of the Pannonian population, creates (1964) also points out that the nestlings are fed only three main clusters with provably distinct diet composi- with vertebrates. According to Haraszthy et al. (1994) it tion. The red-footed falcon diet in Slovakia from 1998, is evident that vertebrates leave fewer traces in nest lin- 2001, 2013 and 2016 creates a separate branch except- ings, possibly because they are eaten whole and are ing the year 2014, which showed a similarity with the usually completely digested by the falcons. In any case, falcons' diet in Vojvodina from 1991 (Purger, 1998). The to know the red-footed falcon diet in as much detail as red-footed falcon diet in Hungary from 1994 (Haraszthy possible, this researcher recommends a combination of et al. 1994) also forms a separate branch. These distinc- multiple research methods. By means of supplementary tions may be a manifestation of not only dissimilar prey analysis of photos of the food from the studied locality, availability in different foraging habitats, but also a dif- we confirmed a higher share of vertebrates in the diet, ferent methodology of sample/data collection and ana- and we extended the diet composition by 6 taxa com- lysis. In the surroundings of the nesting site in pared with the analysis of the food remains in nests Vojvodina there was agricultural land with small fields, (Tab. 3). just as in the Austrian part of the territory near the Comparison of the diet composition of the red- Sysľovské polia SPA. In contrast, the nesting site in footed falcon from southwestern Slovakia (representing Hungary is situated in a puszta biotope typical for its the northern boundary of the Pannonian population) high portion of short grasslands. with published data on the red-footed falcon diet from

25 Tulis F, Slobodník R, LangrafV, Noga M, Krumpálová Z, Šustek Z & Krištín A: Diet composition of syntopically breeding falcon species Falco vespertinus and Falco tinnunculus in south-western Slovakia

F a c t o r s a f f e c t i n g p r e y v a r i- P r e y s i m i l a r i t y i n t w o s y n- a b i l i t y i n t h e c a s e o f t h e t o p i c a l l y b r e e d i n g f a l c o n s E u r a s i a n k e s t r e l Our comparison of the diet composition of both studied In northern and central Europe, the Eurasian kestrel is species showed low diet similarity, however whilst in considered as a species hunting mostly common voles the red-footed falcon diet (found by analysing the food and to a lesser extent invertebrates (Korpimäki 1985, remains in nests) invertebrates prevailed, in the Eurasian Masman et al. 1986, Kochanek 1990, Zmihorski & Rejt kestrel diet in 1998 and 2014 vertebrates predominated 2007), which our results from 1998 and 2014 fully cor- (mainly common vole). Thus the overlapping of the respond with. It is also well known that in the southern food niche between both syntopic species was minimal parts of this species distribution area this ratio changes in this period. The Eurasian kestrel is considered as an gradually and invertebrates predominate (Fattorini et al. opportunistic predator which hunts locally-available 1990, del Hoyo et al. 1994). However, in 2016 we prey (Village 1990), and as explained above, it is able to found a lower proportion of vertebrates in Slovakia as respond flexibly to changing prey availability, and to well, and invertebrates thus represented a major part of adapt its hunting technique. In 2016, when the common the diet. It was just the year 2016 that was characterized vole availability was lower in the studied locality and in by a decrease in the number of common voles in the the Eurasian kestrel diet, invertebrates prevailed (as it studied locality when compared to 2014 (Krištín et al. was in the case of heterospecific falcon species), so the 2017), and the decrease in common vole availability diet similarity and overlapping of the food niche of both could thus have been compensated by increased preda- studied species increased. These results suggest that tion of invertebrates. This type of functional response, mainly in the years of low abundance of common vole, by which in reaction to a decrease in the number of the Eurasian kestrel may be considered a prey rival for common voles the Eurasian kestrel is able to switch to the red-footed falcon. However, more comprehensive hunting insects, has been described by several research- analyses of the Eurasian kestrel biology indicate that the ers (Holling 1965, Korpimäki 1985). Changing meteor- increasing number of insects in the diet correlates neg- ological conditions are a factor that may also affect the atively with the number of breeding pairs of Eurasian diet composition of the Eurasian kestrel. Decreasing kestrel (Itämies & Korpimäki1987), and that the abund- temperature in the non-breeding period leads to altern- ance of common voles is the main factor influencing its ative food, i.e. insects being replaced with birds and population dynamics (Korpimäkki 1984). The assump- mice (Holling 1965, Korpimäki 1985). Furthermore, tion of possible competition or antagonistic behaviour is analysis of the Eurasian kestrel diet in an urbanized en- also disproved by Horváth (1975) who, based on the vironment illustrates that the kestrel is able to broaden behavioural study of both syntopically occurring spe- its diet spectrum opportunistically depending on cies, described the Eurasian kestrel as a peaceable and the specific diet range in the environment, e.g. with tolerant species with regard to the red-footed falcon. bats, swifts and other birds or lizards (Darolová 1989, Romanowski 1996, Zmihorski & Rejt 2007, Mikula et C o n c l u s i o n al. 2013). Constantini et al. (2005) further noted that This study presents the very first comprehensive data on though the hunting area character determines the diet the diet composition of the red-footed falcon from its composition, and there may be a bigger proportion of single nesting locality in Slovakia, which currently rep- more available prey species in the diet, on the other resents the northern border of the species distribution hand the Eurasian kestrel diet reflects a high degree of area in the Pannonian lowlands. In the diet in each of individual feeding behaviour, i.e. individual preferences the five studied years, invertebrates predominated and or abilities to hunt some species of prey regardless of the culmination of the common vole population in 2014 their actual availability. This knowledge may explain had no impact on the diet composition. In comparison the variability in the diet dissimilarity between the nest- with other regions, there was prevalence of Alphitobius ing pairs which we analysed during the individual years. diaperinus, a facultative nidicolous detritophage and It follows from the above that the decreased availability store pest (Dinev 2013) and Calasoma auropunctatum, a of the common vole did not necessarily make a change characteristic component of Carabid assemblages in in the representation of vertebrates and invertebrates in different field crops in warm central and south-eastern the diet explicitly in 2016. European lowlands (Šustek, 1994, Varvara et al. 2010).

We also recorded Alphitobius diaperinus in the nest lin- Cepák J, Klvaňa P, Škopek J, Schröpfer L, Jelínek M, ings of red-footed falcons. In contrast, in the Eurasian Hořák D, Formánek J & Zárybnický J 2008: Atlas kestrel diet in the “vole year” 2014 we recorded a de- migrace ptáků České republiky a Slovenska [Czech crease in otherwise predominating vertebrates and their and Slovak bird migration atlas]. Aventinum, Praha, replacement through the increased consumption of in- PAGES???. [in Czech with English summaries] vertebrates. These results suggest that with increased Costantini D, Casagrande S, Di Lieto G, Fanfani A & consumption of invertebrates, there is consequently in- Dell'Omo G 2005: Consistent differences in feeding creased diet similarity and overlapping of the food habits between neighbouring breeding kestrels. Be- niche of both studied species. Some easily visible haviour 142(9–10): 1403–1415. beetles, like Anisoplia segetum or Zabrus tenebrionides, Cox TF & Cox MAA 2001: Multidimensional scaling. can be hunted just as well on cereal spikes as on the Chapman and Hall, London, 299. ground, in places with a sparse herbage layer or without Cramp S & Simmons KEL 1980: The birds of the west- it. ern Palearctic, vol. 2. Oxford University Press, 695. Darolová A 1989: Potrava sokola myšiara (Falco tin- References nunculus L., 1758) v podmienkach mestskej aglom- Balát F 1971: O zaniklém hnízdišti poštolky rudonohé erácie Bratislavy [Food of Eurasian kestrel (Falco (Falco vespertinus) na jižním Slovensk [On tinnunculus) in Bratislava urban aglomeration]. Bio- abandoned nesting site of the red-footed falcon lógia, Bratislava 44(6): 575–584. (Falco vespertinus) in southern Slovakia]. Ochrana Dinev I 2013: The darkling beetle (Alphitobius diaper- fauny 5: 87–92. [In Czech] inus) – a heath hazard for broiler chicken produc- Balát F & K Bauer 1955: K poznání potravy a hnízdení tion. Trakia Journal of Sciences 1: 1–4. našich poštolek [On the food and breeding of our del Hoyo J, Elliot A & Sargatal J 1994: Handbook of the kestrels]. Zoologické a entomologické listy 18: birds of the world. Vol. 2. New world vultures to 99–104. [In Czech with German summary] guineafowl. Lynx editions, Barcelona, 638. Baláž I, Ambros, Tulis F, Veselovský T, Klimant P & Fattorini S, Manganaro A, Piatella E & Salvati L 1990: Augustiničová G 2013: Hlodavce a hmyzožravce Role of the beetles in raptor diets from a mediter- Slovenska [Rodents and insectivores of Slovakia]. ranean urban area (Coleoptera). Fragmenta Entomo- FPV UKF, Nitra, 198. [In Slovak with English sum- logica 31(1): 57–69. mary] Fargallo JA, Blanco G, Potti J & Viñuela J 2001: Nest- Béltekiné GA, Ezer Á, Fehérvári P, Nagy A, Palatitz P box provisioning in a rural population of eurasian & Solt S 2010: Conservation of red-footed falcon kestrels: breeding performance, nest predation and (Falco vespertinus) in the Pannonian region parasitism. Bird Study 48(2): 236–244. 2006–2009. MME/BirdLife Hungary, Budapest, 11. Ferguson-Lees J & Christie DA 2001: Raptors of the Bezzel E & Hölzinger J 1969: Untersuchungen zur world, London: Christopher Helm, London, 992 p. Nahrung des Rotfußfalken (Falco vespertinus) bei Fülöp Z & Szlivka L 1988: Contribution to the food Ulm. Aus der Staatlichen Vogelschutzwarte biology of the red-footed falcon (Falco vespertinus) Garmisch–Partenkirchen bei der Baye 8: 446–451. Aquila 95: 174–181. BirdLife International 2016a: Falco vespertinus. The Giljarov MS 1964: Opredelitel obitajushtchich v IUCN red list of threatened species 2016: potchve litchinok nasekomych. [Key to identifica- e.T22696432A84476145. Retrieved March 13, tion of insect larvae living in the soil]. Nauka, 2017, from http://dx.doi.org/10.2305/IUCN.UK. Moskva, 919. [in Russian] 2016–3.RLTS.T22696432A 844 76145.en. Haraszthy L, Rékási J & Bagyura J 1994: Food of the BirdLife International 2016b: Falco tinnunculus. The red-footed falcon (Falco vespertinus) in the breeding IUCN red list of threatened species 2016: period. Aquila 101: 93–110. e.T22696362A93556429. Retrieved June 20, 2017, Holling CS 1965: The functional response of predators from http://dx.doi.org/10.2305/IUCN.UK.2016–3. to prey density and its role in mimicry and popula- RLTS.T22696362A93556429.en. tion regulation. The Memoirs of the Entomological Borcard D, Gillet F & Legendre P 2011: Numerical Society of Canada 97: 5–60. Ecology with R. Springer, New York, PAGES???. Horváth L 1963: A kékvércse (Falco vespertinus L.) és a

27 Tulis F, Slobodník R, LangrafV, Noga M, Krumpálová Z, Šustek Z & Krištín A: Diet composition of syntopically breeding falcon species Falco vespertinus and Falco tinnunculus in south-western Slovakia

kis őrgébics (Lanius minor Gm.) élettörténetének E, Kovács A, Marshall EJP, Tscharntke T & Verhulst összehasonlító vizsgálata I. A tavaszi érkezéstől a J 2009: On the relationship between farmland biod- fiókák kikeléséig [Comparing life history of red- iversity and land-use intensity in Europe. Proceed- footed falcons (Falco vespertinus L.) and lesser grey ings of the Royal Society B: Biological Sciences shrikes (Lanius minor Gm.) from spring arrival to 276: 903–909. DOI: 10.1098/rspb.2008.1509. hatching]. Vertebrata Hungarica 5(1–2): 69–121. [in Kochanek HM 1990: Ernährung des Turmfalken (Falco Hungarian with German summary] tinnunculus): Ergebnisse von Nestinhaltsanalysen Horváth L 1964: A kék vércse (Falco vespertinus L.) és und automatischer Registrierung. Journal of Orni- a kis őrgébics (Lanius minor Gm.) élettörténetének thology 131(3): 291–304. összehasonlító vizsgálata II. A fiókák kikelésétől az Korpimäki E 1984: Population dynamics of birds of őszi vonulásig [Comparative study on the life his- prey in relation to fluctuations in small mammal tory of the red-footed falcon (Falco vespertinus L.) populations in western Finland. Annales Zoologici and the lesser grey shrike (Lanius minor Gm.) II. Fennici 21(3): 287–293. From the hatching of chicks in the autumn migra- Korpimäki E 1985: Diet of the kestrel Falco tinnunculus tion]. Vertebrata hungarica 6(1–2): 13–39. [in Hun- in the breeding season. Ornis Fennica 62(3): garian with German summary] 130–137. Horváth L 1975: Social pattern and behavior between Korpimäki E 1986: Diet variation, hunting habitat and two falco species (Aves). Annales historico-nat- reproductive output of the kestrel Falco tinnunculus urales Musei nationalis Hungarici 67: 327–331. in the light of the optimal diet theory. Ornis Fennica Chinery M 1987: Pareys Buch der Insekten: Ein Feld- 63(3): 84–90. führer der europäischen Insekten [Pareys book of Korpimäki E & Norrdahl K 1991: Numerical and func- insects: A field guide of european insects]. Verlag tional responses of kestrels, short-eared owls, and Paul Parey, Hamburg and Berlin, PAGES??????. [in long-eared owls to vole densities. Ecology 72(3): German]. 814–826. Itämies J & Korpimäki E 1987: Insect food of the Kotymán L, Solt S, Horváth É, Palatitz P & Fehérvári P kestrel, Falco tinnunculus, during breeding in west- 2015: Demography, breeding success and effects of ern Finland. Aquilo, Ser. Zoologica 25: 21–31. nest type in artificial colonies of red-footed falcons Jacob J & Tkadlec E 2010: Rodent outbreaks in Europe: and allies. Ornis Hungarica 23(1): 1–21. dynamics and damage, 207–223. In: Singleton GR, Kreft H & Jetz W 2010: A framework for delineating Belmain S, Brown PR & Hardy B (eds.), Rodent biogeographical regions based on species distribu- outbreaks: ecology and impacts, International Rice tions. Journal of Biogeography 37: 2029–2053. Research Institute, Los Banos, Philippines, 289. Krištín A, Tulis F, Klimant P, Bacsa K & Ambros M Jacob J, Manson P, Barfknecht R & Fredricks T 2013: 2017: Food supply (Orthoptera, Mantodea, Rodentia Common vole (Microtus arvalis) ecology and man- and Eulipotyphla) and food preferences of the red- agement: implications for risk assessment of plant footed falcon in Slovakia. Slovak Raptor Journal 11: protection products. Pest Management Science 1–14. DOI: 0.1 51 5/srj-201 7-0005. 70(6): 869–878. Lebedeva NV & Ermolaev AI 2012: Colonial nesting of Karaska D, Trnka A, Krištín A & Ridzoň J 2015: red-footed falcon Falco vespertinus L. in near lake Chránené vtáčie územia Slovenska. [Special protec- Manych-Gudilo. Arid Ecosystems 2(3): 177–185. tion areas of Slovakia] Štátna ochrana prírody SR, Legendre P & Legendre L 1998: Numerical ecology. Banská Bystrica, 380. Elsevier Science B.V., Amsterdam, Netherlands, Keve A & Szijj J 1957: Distribution, biologie et ali- 852. mentation du faucon kobez Falco vespertinus L. en Masman D, Gordijn M, Daan S & Dijkstra C 1986: Hongrie. Alauda 25(1): 1–23. Ecological energetics of the kestrel: ﬁeld estimates Kečkéšová L & Noga M 2008: The diet of the common of energy intake throughout the year. Ardea 74: kestrel in the urban environment of the city of Nitra. 24–39. Slovak Raptor Journal 2: 81–85. Mikula P 2012: Zloženie potravy sokola myšiara (Falco Kleijn D, Kohler F, Báldi A, Batáry P, Concepción ED, tinnunculus) počas letného obdobia v Bardejove na Clough Y, Díaz M, Gabriel D, Holzschuh A, Knop severovýchodnom Slovensku. [Diet of the common

kestrel (Falco tinnunculus) during summer in scarcity in an urban kestrel Falco tinnunculus popu- Bardejov in northeastern Slovakia] Sylvia 48: lation. Bird Study 54(3): 353–361. 109–114. [In Slovak with English summary] Riegert J, Lövy M & Fainová D 2009: Diet composition Mikula P, Hromada M & Tryjanowski P 2013: Bats and of common kestrels Falco tinnunculus and long- swifts as food of the European kestrel (Falco tin- eared owls Asio otus coexisting in an urban envir- nunculus) in a small town in Slovakia. Ornis Fen- onment. Ornis Fennica 86(4): 123–130. nica 90(3): 178 –185. Romanowski J 1996: On the diet of urban kestrels Nuhlíčková S, Krištín A, Degma P & Hoi H 2016: (Falco tinnunculus) in Warsaw. Buteo 8: 123–130. Variability in hoopoe Upupa epops diet: annual and Rosenberg K & Cooper RJ 1990: Approaches to avian sampling effect. Folia Zoologica 65(3): 189–199. diet analysis. Studies in Avian Biology 13: 80–90. Oksanen J, Blanchet FG, Kindt R, Legendre P, Minchin Szövényi G 2015: Orthopteran insects as potential and PR, O’Hara RB, Simpson GL, Solymos P, Stevens preferred preys of the red-footed falcon (Falco ves- MHH & Wagner H 2013: Vegan: community eco- pertius) in Hungary. Ornis Hungarica 23(1): 48–57. logy package, version 2.0–8. Retrieved on February Slobodník R, Chavko J, Lengyel J, Maderič B & Noga 22, 2017 from http://cran.r–project.org/web/pack- M 2014: Prežije na Slovensku sokol červenonohý? ages/vegan/index.html. [Will red-footed falcon survive in Slovakia?], 23. In: Palatitz P, Fehérvári P, Solt, S, Kotymán L, Neidert D & Lešo P (ed.): Aplikovaná ornitológia. Zborník ab- Harnos A 2011: Exploratory analyses of foraging straktov z 26. stredoslovenskej ornitologickej kon- habitat selection of the red-footed falcon (Falco ferencie [Applied ornithology. Book of the abstracts vespertinus). Acta Zoologica Academiae Scientiar- from the 26th Central Slovak Ornithological Confer- um Hungaricae 57(3): 255–268. ence], TU vo Zvolene, Zvolen, 29. [In Slovak] Palatitz P, Solt S, Horváth É & Kotymán L 2015: Hunt- Slobodník R, Chavko J, Lengyel J, Noga M & Maďerič ing efficiency of red-footed falcons in different hab- B 2016: Vývoj, vybrané hniezdne charakteristiky a itats. Ornis Hungarica 23(1): 32–47. ochrana populácie sokola červenonohého na JZ Pechacek P & Krištín A 2004: Comparative diets of Slovensku [Development, selected nesting charac- adult and young three-toed woodpecker in a teristics and red-footed falcon population conserva- european alpine forest community. Journal of Wild- tion in the southwestern Slovakia], 193–195. In: life Management 68 (3): 683–693. Krumpálová Z, Zigová M & Tulis F (eds.), Zborník Pianka ER 1973: The structure of lizard communities. príspevkov z vedeckého kongresu “Zoológia 2016” Annual Review of Ecology and Systematics 4: [Proceeding from the science congress “Zoology 53–74. 2016”], Univerzita Konštatína Filiozofa v Nitre, Ni- Purger J 1998: Diet of red-footed falcon Falco vesper- tra, 249. [In Slovak] tinus nestlings from hatching to fledging. Ornis Szövényi G 2015: Orthopteran insects as potential and Fennica 75(4): 185–191. preferred preys of the red-footed falcon (Falco Purger J 2001: Defence behaviour of red-footed falcons vespertinus) in Hungary. Ornis Hungarica 23(1): Falco vespertinus in the breeding period and the ef- 48–57. fects of disturbance on breeding success. Ornis Fen- Šustek Z 1994: Impact of pollution by nickel leaching nica 78(1): 13–21. rest on Carabidae, Silphidae and Staphylinidae in the Purger J & Tepavcevic A 1999: Pattern analysis of red- surroundings of the nickel smelting plant at Sereď footed falcon (Falco vespertinus) nests in the rook (Slovakia). Biologia, Bratislava 46: 709–721. (Corvus frugilegus) colony near Torda (Voivodina, Šustek Z 2009: Changes of secondary productivity of Yugoslavia) using fuzzy correspondences and en- Carabid communities (Insecta: Coleoptera) in natur- tropy. Ecological Modeling 117(1): 91–97. al forests ecosystems in relation to geological sub- R Core Team 2016: R: A language and environment for strate and vertical zonality. Oltenia. Studii şi statistical computing. R Foundation for Statistical comunicoăi. Ştiinţele Naturi 25: 83– 90. Computing, Vienna, Austria. Retrieved March 31, Tella JL, Forero MG, Hiraldo F & Donázar JA 1998: 2016, from URL https://www.R–project.org/. Conflicts between lesser kestrel conservation and Riegert J, Dufek A, Fainová D, Mikeš V & Fuchs R European agricultural policies as identified by habitat 2007: Increased hunting effort buffers against vole use analyses. Conservation Biology 12(3): 593–604.

29 Tulis F, Slobodník R, LangrafV, Noga M, Krumpálová Z, Šustek Z & Krištín A: Diet composition of syntopically breeding falcon species Falco vespertinus and Falco tinnunculus in south-western Slovakia

Tryjanowski P, Karg MK, Karg J 2003: Food of the red- tion actually reduce foraging habitat for breeding backed shrike Lanius collurio: a comparison of three lesser kestrels? The role of crop types. Biological methods of diet analysis. Acta Ornithologica 38: Conservation 122(4): 643–648. 59–64 Varvara M, Cimişliu C & Šustek Z 2012: Distribution Tulis F, Krumpálová Z, Šustek Z, Noga M & Slobodník and abundance of Calosoma auropunctatum Herbst R 2016: Potrava dvoch sympatricky sa vyskytujú- 1784 (Coleoptera: Carabidae) in some agricultural cich druhov sokola červenonohého Falco vesper- crops in Romania, 1977–2010. Oltenia. Studii şi tinus a sokola myšiara Falco tinnunculus na JZ comunicări. Ştiinţele Naturi 28: 79–90. Slovensku. [Diet of two sympatric species of falcons Village A 1982: The diet of kestrels in relation to vole Falco vespertinus a Falco tinnunculus in SW Slov- abundance. Bird Study 29(2): 129–138. akia], 223–224. In: Krumpálová Zigová M & Tulis F Village A 1990: The kestrel. T. &. A.D. Poyser, London, (eds): Zborník príspevkov z kongresu “Zoológia 352. 2016”, Univerzita Konštatína Filiozofa v Nitre, Ni- Żmihorski M & Rejt Ł 2007: Weather-dependent vari- tra, 249. [In Slovak] ation in the cold-season diet of urban kestrels Falco Ursua E, Serrano D & Tella J L 2005: Does land irriga- tinnunculus. Acta Ornithologica 42: 107–113.

Received: 5. 9. 2017 Accepted: 4. 11. 2017