Nesting and Non-Nesting Occurrence of the Short-Eared Owl

Slovak Raptor Journal 2013, 7: 73–80. DOI: 10.2478/srj-2013-0006. © Raptor Protection ofSlovakia (RPS)

Nesting and non-nesting occurrence of the short-eared owl Asio flammeus in the Záhorie region (SW Slovakia) Hniezdny a mimohniezdny výskyt myšiarky močiarnej Asio flammeus na Záhorí (JZ Slovensko)

Michal NOGA & Martin DOBRÝ

Abstract: The short-eared owl is a regular migrant and hibernant in the Záhorie region (SW Slovakia), though this species mostly escapes attention. In 1998 the species was found nesting in this region, and in 2012 individuals showing territorial behaviour were regularly observed, with high probability of nesting. Nesting habitats were localities with a high representation of meadows, corresponding to the preferred nesting sites in Slovakia. The foraging range of wintering birds was comparable with those from neighbouring regions (W Slovakia, Hungary), but with a higher number of harvest mice Micromys minutus and long-tailed field mice Apodemus sylvaticus. In both years when the nesting of birds was recorded, snowfall was significantly lower. Food sources were not monitored at these localities. Abstrakt: Myšiarka močiarna je v regióne Záhoria (JZ Slovensko) pravidelným migrantom a hibernantom, hoci tento druh zväčša uniká pozornosti. V roku 1998 bolo v tomto regióne zistené hniezdnenie druhu a v roku 2012 boli opakovane pozorované teritoriálne správajúce sa jedince, s vysokou pravdepodobnosťou hniezdiace. Hniezdnym prostredím boli lokality s vysokým zastúpením lúk, čo zodpovedalo preferovanému hniezdnemu prostrediu na Slovensku. Potravné spektrum zimujúcich jedincov je porovnateľné s údajmi zo susedných regiónov (Z Slovensko, Maďarsko), má ale vyššie zastúpenie myšiek drobných Micromys minutus a ryšaviek krovinných Apodemus sylvaticus. V oboch rokoch, kedy došlo k hniezdnym prejavom sov boli výrazne nižšie snehové zrážky. Potravná ponuka na týchto lokalitách sledovaná nebola.

Key words: snow cover, wintering, nesting, diet, Natura 2000

Michal Noga, Raptor Protection of Slovakia, Kuklovská 5, 841 04 Bratislava 4, Slovakia. E-mail: [email protected]. Martin Dobrý, Raptor Protection of Slovakia, Kuklovská 5, 841 04 Bratislava 4, Slovakia. E-mail: [email protected]. Acknowledgements: We would like to thank everyone involved for providing their data, insights and consultation to this paper. In particular, we wish to thank David Horal, Rudolf Jureček, Ján Svetlík, Gašpar Čamlík, Alexander Sharikov, Miroslav Čapek, Radovan Václav, Vlasta Škorpíková, Reiner Raab, Erik Martinec and Jozef Madzin, as well as Jana Bacigalová from the Slovak Hydrometeorological Institute in Bratislava and Viera Stanová-Šefferová and Rastislav Lasák from the Institute of Applied Eco- logy Daphne. Data on the occurrence of the short-eared owl were collected during monitoring supported by the project CORO- SKAT Conservation of Raptors and Owls – Slovakia-Austria in the Slovak-Austrian cross-border cooperation programme 2007–2013, financed by the European Regional Development Fund. We are grateful to Marcel Uhrin for his valuable comments and we thank reviewers, David Horal and Vlasta Škorpíková, for their comments, which contributed to the improvement of the present research.

Introduction estimated nesting population abundance for the whole In Slovakia the short-eared owl Asio flammeus (Pontop- territory of Slovakia (0–50 pairs) and in the estimated pidan, 1763) regularly occurs during migration and in wintering population (100–1,000 individuals) for the winter. This species nests irregularly and infrequently. It period 1980–2000 (Danko et al. 2002). is a typical fluctuant species with significant variations Only a few specific reports of the occurrence and in abundance. Appropriate local and trophic conditions nesting of short-eared owls have been published from are considered to be prerequisites of its nesting. These the Záhorie region (W Slovakia). Nesting was men- conditions are the gradation of abundance of the com- tioned in 1965 (Balát 1965), and later data on the nest- mon vole Microtus arvalis and the presence of taller ing at the Devínske jazero location in the years 1989, herbaceous vegetation (reed, ruderal communities, etc.). 1990 and 1998 (Tomovčík et al. in Šeffer & Stanová Species fluctuation also means a large range in the 1999) were published without more details.

73 Noga M & Dobrý M: Nesting and non-nesting occurrence of the short-eared owl Asio flammeus in the Záhorie region (SW Slovakia)

acoustic monitoring. Olympus DM 550 and Olympus DM 650 digital voice recorders were used in this type of monitoring, with the recorders placed in suitable wetland and meadow areas (Sekule, Borský Svätý Jur, Zá- vod – Abrod, Závod – Húšky, Gajary and Rohožník – Krížnica). They also recorded during the times of day with the highest supposed acoustic activity of short- eared owls (two hours after sunset, two hours before sunrise and one hour after midnight). A total of 220 hours of recordings were obtained. Our own data were supplemented with the observations of other authors, or by data extracted from online databases (Birding Slovakia, http://www.birding.sk/ and the database AVES Symfony; http://aves.vtaky.sk/); from records of the State Nature Conservancy of the Slovak Republic and the office of Administration of the Záhorie Protected Landscape Area (PLA Záhorie) and from Archive Auring-Verein (Austria). The nesting period (individuals showing territorial behaviour) and the occurrence during migration and in winter (from August to April, or individuals without nesting and territorial behaviour) were evaluated separ- ately. Data on the food composition of short-eared owls were obtained from the analysis of pellets. They were collected in daily roost places at two localities – the Moravský Svätý Ján locality (December 15, 2011; March 3, 2012) and a disproportionately smaller sample at the Petrova Ves locality (November 26, 2006). Pellets Fig. 1 . The map of the study area. Yellow square – nesting were processed in a 5% NaOH solution. Skulls of mam- areas (supposed breeding), green circle – Asio flammeus ob- mals and avian bones (skull, beak, humerus and tar- servations, blue pentagram – meteorological stations, green li- sometatarsus) were separated from the obtained ne – study area. osteological material and were determined using the Fig. 1 . Mapa sledovaného územia. Žltý štvorec – hniezdne lokality (predpokladané hniezdenie), zelený kruh – pozorovania available determination key (Anděra & Horáček 2005) Asio flammeus, modrý pentagram – meteorologické stanice, and by our own comparative collection. zelená linia – sledované územie. Data on vegetation land cover and landscape structure were obtained from the field work and by using available Methods satellite images (Google Earth). Specific additional data This study summarizes unpublished data and details were provided by the Institute of Applied Ecology from published information on the nesting, migration Daphne, and the Slovak Hydrometeorological Institute in and wintering of short-eared owls in the Záhorie region Bratislava provided meteorological data. There were pro- (Šeffer & Stanová 1999, Zuna-Kratky et al. 2000 cessed data from the period between 1997 and 2013. and Danko et al. 2002). This area, shown in Fig. 1, includes the following geomorphological units: the Bor- Results and discussion ská nížina Lowland, the Chvojnická pahorkatina M i g r a t i o n a n d w i n t e r i n g Upland and the Slovak part of the Dolnomoravský úval The first observations of short-eared owls were recorded Ravine. Data were collected in direct observation, often in the middle of October (October 19, 2008, October 14, during the winter counting of the hen harriers Circus 2011). In wintering areas, short-eared owls were seen cyaneus. The species was determined during the monit- throughout the winter period. The increased number of oring of other species from 2011 to 2013 during con- species occurrences in March may signal the ongoing trols of suitable nesting habitats and also during spring migration. In most cases short-eared owls were

74 Slovak Raptor Journal 2013, 7: 73–80. DOI: 10.2478/srj-2013-0006. © Raptor Protection ofSlovakia (RPS) identified in meadow habitats or ruderal sites. However, they did not avoid settlements (two cases, Devínska Nová Ves, Senica). The species was even observed on a xerothermic hillside (Devínska Nová Ves) and on a heath (Rohožník). More than two-thirds of the observations came from areas included in the Natura 2000 network (Special Protection Area Záhorské Pomoravie, Special Area of Conservation Bežnisko). A summary of all observations of short-eared owls is provided in Ap- pendix 1. It is not possible to precisely express seasonal dy- namics because of the hidden way of the life, different intensity of visits at localities and targeted control of the Fig. 2. Non-nesting occurrences of short-eared owls, the meadow vegetation. Thus, these are only informative number of observations (n = 28) and the number of recorded data. The highest number of records was from Novem- individuals (n = 78). Blue columns – no. of observations, red ber and December and the highest peak was in the columns – no. of recorded inds. second half of November, with 21% of all observations Obr. 2. Mimohniezdne výskyty myšiarok močiarnych, počet pozorovaní (n = 28) a počet zaznamenaných jedincov (n = 78). and 29.50% of all recorded individuals (Fig. 2). There Modré stĺpce – počet pozorovaní, červené stĺpce – počet jedin- are also most occurrence data from November from cov. eastern Slovakia (from the period between 1872 and 2007, Danko 2008). with only a minimal range of free water surface, or quite N e s t i n g a n d n e s t i n g often without water. The surrounding land is made up of o c c u r r e n c e s mown meadow vegetation and agricultural land (in The Devínske jazero locality, 1998. The Devínske 2012, sunflower, rape, cereals). jazero locality is a large complex (1,264 ha) of flood- There are numbers of records on the wintering of plain meadows (Cnidion venosi communities) situated short-eared owls at this locality, but nesting has never in an area between a river dyke and the Morava River in been confirmed. The possibility of an overlooked nest- the cadastral areas of the village of Vysoká pri Morave, ing is lower here than in other parts of the Záhorie re- the village of Zohor and the town of Stupava. In the gion because of the frequent movements of 1998 nesting season, the first observations were from ornithologists in this area. In the winter of 2011/2012, late April. Considering the significant territorial beha- the first observations occurred on October 14, 2011, viour of an observed individual bird during the day, when two birds were startled from the meadow vegeta- there was a high probability of nesting. We observed, tion. On November 11, 2011, a check did not find any for example, the carrying of food in mid-May (May 16, occurrence of this species, though on November 28, 1998). On May 18, a potential nesting habitat was 2011, two individuals were found. On December 13, checked but without finding the nest. On June 3, 2011, four individuals were observed. A one-time however, we were more successful. One flying juvenile counting took place on December 15, 2011, when was startled during a check of the meadow vegetation. twelve individuals were startled (together with D. Horal, We had assumed at least one hidden juvenile because of T. Bělka and R. Mikusek). Two birds remained circling the behaviour of an adult bird. The locality was not above the locality and aggressive territorial behaviour checked later. Based on the observation of the flying ju- was observed. One bird attacked an overflying rough- venile, we can calculate back to the start of hatching: it legged buzzard Buteo lagopus. The locality was later began during the first part of May; thus, the beginning monitored from a distance to avoid disturbing wintering of incubation was in the first part ofApril. or nesting birds. Vegetation was directly checked on March 3, 2012, and six birds were startled (four of them Moravský Svätý Ján, Piesočná locality, 2012. The flew out from one place in the sedge) but with no sign locality is approximately 1.6 km west of the village of of breeding behaviour. During detailed browsing of the Moravský Svätý Ján. Two small dead branches of the vegetation an eggshell was found (probably destroyed Morava River lie in its centre, overgrown by sedge and by predation). Its size and colour resembled an egg of

75 Noga M & Dobrý M: Nesting and non-nesting occurrence of the short-eared owl Asio flammeus in the Záhorie region (SW Slovakia)

the short-eared owl. The species was found even at the hours of records in March (March 3–6, 2012) and 27 end of April at this location (2 inds., April 28, 2012, hours of records in May (May 2–10, 2012), but this J. Svetlík in litt.). A fresh pellet was also found in this sample was too small for evaluating the efficiency of the period, but we do not know if it belongs to this species method. (the place of finding corresponded to locations of pellets of short-eared owls in the winter season). N e s t i n g h a b i t a t s e l e c t i o n No nest with nestlings or with a clutch was found in any Skalica, 2012. The locality, which is approximately of the mentioned cases. We were able to locate the nest- 1.5 km north-west of the town of Skalica, is made up of ing habitat by observations. In 1998, short-eared owls utilised agricultural area (in 2012, alfalfa, meadow ve- nested in a regularly mown meadow (Cnidion venosi getation). communities). In 2012 birds were observed displaying The first record of observation here was on March near Skalica, and they were staying here in higher 24, 2012. One or two individual birds were seen dis- grasslands. If nesting occurred in the Moravský Svätý playing. Since then this species has been regularly re- Ján locality, a nest could be placed in two types of ve- corded (one to three inds.). Two individuals were seen getation – in mown meadow vegetation or in sedge. displaying and attacking carrion crows Corvus corone Table 1 shows the habitat cover or types of land use and marsh-harriers Circus aeruginosus. One part of this in an area of 150 ha (with a radius 0.69 km). The area of locality consisted of alfalfa and the other part of mead- the short-eared owl territories varies from 42 ha to 112 ow vegetation, which was the main area of the short- ha (Village 1987). eared owls. Agro-technical interventions on the land The cases of nesting presented in this study were were delayed until the expected date of fledging as part similar to those from other areas of Slovakia, Bo- of a partnership with the office of the Administration of hemia and Moravia. Most nests were located in similar PLA Záhorie, the State Nature Conservancy of the habitats (Hudec & Šťastný 2005, Danko 2008). The Slovak Republic and the land users. On May 23, again cover of the habitats in the defended territory had a high two individuals were seen attacking marsh-harriers. The representation of meadow vegetation (25 – 77%). Two last check was carried out on June 2, 2012. Eggshells localities (Devínske jazero and Moravský Svätý Ján) were found, and their shape, colour and size resembled were also roost places of hen harriers Circus cyaneus, eggs of the short-eared owl. Short-eared owl individuals which was interesting, but not surprising. Both locations were not seen. The locality was not checked later. are stable and regular wintering areas. They were occu- pied from October to March with a maximum number of A c o u s t i c m o n i t o r i n g 17 (Devínske jazero, 2011) and 27–30 individual hen More than 220 hours of recordings were obtained at six harriers (Moravský Svätý Ján, 2011). Both species localities, but no calls of short-eared owls were record- probably have similar habitat and foraging require- ed (this species was not recorded visually either). No ments. No interactions were observed between these calls were recorded at the assumed nest site at two species, though such interactions are common in Moravský Svätý Ján – Pačitov either. We obtained eight Hungary (Meszáros et al. 2002).

Tab. 1 . Landscape structure in the assumed nesting territory of short-eared owls. Wetland vegetation mainly includes sedge and reed stands, non-forest vegetation includes tree-lines, groups of trees, solitary standing trees and scrub formations. Tab. 1 . Krajinná štruktúra v predpokladanom hniezdnom teritóriu myšiarok močiarnych. Mokraďná vegetácia zahŕňa najmä ostrice a porasty trste obyčajnej, mimolesná vegetácia zahŕňa stromoradia, skupinky stromov, solitérne stojace stromy a krovinné formácie. locality / lokalita Skalica Moravský Svätý Ján Devínske jazero habitat type / typ prostredia [%] arable land / orná pôda 3.62 67.1 9 0 meadow vegetation, grassland / lúčne porasty, lúky 77.45 26.93 77.06 wetland vegetation / mokraďná vegetácia 1 .08 4.85 9.53 non-forest vegetation / mimolesná vegetácia 2.11 0.1 7 399 forest / lesný porast 1 5.31 0 3.20 grassland on dykes / trvalé trávne porasty na hrádzach 0.44 0.86 0 water area / vodná plocha 0 0 6.22

76 Slovak Raptor Journal 2013, 7: 73–80. DOI: 10.2478/srj-2013-0006. © Raptor Protection ofSlovakia (RPS)

F o r a g i n g e c o l o g y The most significant factor affecting the nesting of The total number of prey items determined from pellets the short-eared owl is the abundance gradation of the was 139 (Table 2). The common vole Microtus arvalis common vole. Data on the nesting of short-eared owls made up nearly 85% of them. The harvest mouse Mi- in “mouse years” (those with higher abundance) are cromys minutus and the long-tailed field mouse Apo- mentioned in the older literature (Kněžourek 1910, demus sylvaticus had equal representation (5%). The Mensdorff-Pouilly 1931, Musílek 1931). They are also collected data were comparable with data from Slovakia found in almost every study of their nesting areas in (Trnka & Obuch 2006, Danko 2008), the Czech Repub- Slovakia (Lengyel 2001, Demeter 2005, Lengyel 2006, lic (Hudec & Štastný 2005) and Hungary (Meszáros et Danko 2008) or other areas in Central Europe (Oláh al. 2002). The increased representation of the harvest & Vasas 2002, Kovács 2002). Unfortunately, there are mouse in the Záhorie region may reflect a higher rep- no data for abundance or for peaks of common vole resentation of meadows and wetland in the study areas. gradational cycles available in the study region. In 1998, The harvest mouse had a statistically higher representa- when the short-eared owl nested at the Devínske jazero tion even in the diet of the barn owl Tyto alba and the locality, the analysis of long-eared owl food in the long-eared owl Asio otus in the Záhorie region (Noga Podunajská nížina Lowland showed a common vole 2004, 2007). gradation (the regions were separated by 95 km). This gradation could have a local character, meaning that N o t e t o f a c t o r s a f f e c t i n g t h e specific food sources could be different at the individual n e s t i n g o f t h e s h o r t - e a r e d nest sites. It should be noted that the Devínske jazero o w l locality is situated in periodically flooded areas, and the The nesting of short-eared owls often has an eruptive abundance of the common vole is lower than in the character. Nesting attempts as far as 1,000 km or 1,900 neighbouring crops. In that year (1998) the nesting of a km from the continuous area of distribution have been short-eared owl was also recorded in the Nové Zámky previously published (Therrien 2010, König & Weick district in south-western Slovakia (Lengyel 2001), as 2008). Nesting outside of nesting areas was observed in well as in Central Moravia in the Czech Republic years when the population of the main prey Microtus sp. (Dohnal & Dufek 1998). In 2012 nest occurrences were was in a phase of attenuation in the nesting area recorded at the Moravský Svätý Ján locality and in (Korpimäki 1984). Eruptions occur when there is an ex- Skalica. Short-eared owls also nested in an increased cess of food sources in the nesting season or when such number in Austria (NP Neusiedler See – Seewinkel, six excess is followed by poor food availability. They may pairs, Raab in verb.). These two areas were located tens also occur when the nesting density is relatively high of kilometres apart. The question is whether the com- and is not influenced by the food-supply (Koenig mon vole gradation had a supra-regional character. It & Knops 2001). could have occurred at each of these localities or there may be other reasons for nesting. One of the other factors that may also affect the Tab. 2. The diet of the short-eared owl in Záhorie region; nesting of this species is the weather. Table 3 shows se- N – the number of prey samples, N(%) – the percentage of taxa lected meteorological data from the study areas, resp. in the total diet from nearby weather stations. The compared time period Tab. 2. Potrava myšiarky močiarnej na Záhorí; N – počet was relatively short. Winter periods with nesting or with exemplárov koristi, N(%) – percentuálny podiel taxónov recorded nest behaviour (such periods are in bold in v celkovej potrave Table 3) were those with low snowfall. It is possible that locality / lokalita 1 2 taxa / taxón N N ∑ N (%) the snow depth and the number of days of continuous Microtus arvalis 11 3 5 11 8 84,89 snow cover may be an important factor for nesting. We Micromys minutus 7 1 8 5,76 cannot exclude the fact that warm and dry winters create Apodemus sylvaticus 8 8 5,76 optimal conditions for common voles. Crocidura leucodon 1 1 0,72 No weather effect was confirmed in any of the elev- Chloris chloris 1 1 0,72 en analysed cases during the research of bird eruptions Emberiza citrinella 1 1 0,72 Fringilla coelebs 1 1 0,72 in North America (Koenig & Knops 2001). Granivorous Passeriformes 1 1 0,72 species were observed, but their mechanism and me- ∑ 1 33 6 1 39 1 00 thods of food searching and food availability are differ-

77 Noga M & Dobrý M: Nesting and non-nesting occurrence of the short-eared owl Asio flammeus in the Záhorie region (SW Slovakia)

Tab. 3. Selected meteorological data, Devín locality, Moravský Svätý Ján locality and Skalica Tab. 3. Vybrané meteorologické dáta, lokalita Devín, lokalita Moravský Svätý Ján a Skalica

winter / zima FD-SC LD-SC ND-SC AvHi-SC To-SC D-wS AvHI-NSC Devínske jazero 1 995/1 996 5. 11 . 1 995 3. 4. 1 996 33 9.09 1 56 32 3.1 2 1 996/1 997 26. 11 . 1 996 1 8. 3. 1 997 1 7 7.1 8 1 22 1 2 3.66 1997/1998 24. 11. 1997 22. 3. 1998 4 4.25 17 4 4.25 Moravský Svätý Ján 2009/201 0 1 8. 1 2. 2009 11 . 3. 201 0 28 1 2.98 98 23 4.26 201 0/2011 27. 11 . 201 0 3. 3. 2011 1 8 4.05 90 24 3.75 2011/2012 21. 12. 2010 17. 2. 2012 8 2.5 21 11 1.9 201 2/201 3 29. 1 0. 201 2 3. 4. 201 3 38 5.78 1 32 41 3.22 Skalica 2009/201 0 1 9. 1 2. 2009 11 . 3. 201 0 20 1 5.75 1 04 27 3.81 201 0/2011 29. 11 . 201 0 3. 2. 2011 1 5 5.28 79 1 8 4.3 2011/2012 17. 1. 2011 17. 2. 2012 5 2.2 9 7 1.28 201 2/201 3 1 0. 1 2. 201 2 3. 4. 201 3 26 4.34 1 02 32 3.1 9 FD-SC – the first day with snow cover / prvý deň so snehovou pokrývkou, LD-SC – the last day with snow cover / posledný deň so snehovou pokrývkou, ND-SC – the number of snow cover days / počet dní so snehovou pokrývkou, AvHi-SC – the average snow depth (cm) / priemerná výška snehovej pokrývky (cm), To-SC – the total snow cover (cm) / celkový úhrn snehovej pokrývky (cm), D-wS – days with snowfall / dni so snežením, AvHI-NSC – the average amount of new snow (cm) / priemerná výška nového snehu (cm). Bold italic – years with short-eared owl supposed breeding / territorial behaviour / tučná kurzíva – roky, kedy došlo k zahniezdeniu, alebo teritoriálnemu správaniu sov na uvedených lokalitách. ent. A twelve-year study of short-eared owls and long- locality, Skalica). Eggshells which probably belonged to eared owls in the Moscow region, Russia, illustrated the the short-eared owl were found at both localities. The impact of the weather factors. The owls’ arrival to the selection of defended territory corresponds to the nest site in the study area depended mostly on these preferred nesting habitat in Slovakia. The foraging range factors while the laying date depended mainly on the of wintering birds in the Záhorie region corresponds availability of food (Sharikov et al. 2012). with data from neighbouring regions, with a higher The studied nesting areas in the Záhorie region did representation of harvest mice Micromys minutus and not significantly change during the seasons because of long-tailed field mice Apodemus sylvaticus. Due to the the relatively large representation of meadow vegeta- absence of data on common vole abundance it is not tion. possible to say whether the increased abundance of this Nesting of short-eared owls is not usually recorded species was the cause of nesting or the nesting with each local or regional overgrowth of the common behaviour of short-eared owls in the Záhorie region vole. These facts indicate that sufficient food sources between 1998 and 2012. Meteorological data showed and a suitable nesting habitat are the reasons for nesting significantly lower amounts of snowfall in the years but probably not the cause of nesting. when birds were observed nesting or with nesting ex- The start of nesting invasions or of individual nest- pressions. ings may also be caused by other factors, such as food availability in the northern parts of Europe or the course References and character of the winter part of the year, particularly Anděra M & Horáček I 2005: Poznáváme naše savce the amount of snowfall. [Determining Our Mammals]. Sobotáles, Praha, 327. [In Czech] Conclusion Balát F 1965: Hnízdění kalouse pustovky Asio flammeus The short-eared owl is a rare but regular migrant and (Pontopp.) v jihozápadní části Slovenska [Breeding wintering species in the study area. There is a high of the short-eared owl Asio flammeus (Pontopp.) in probability that it escapes attention in this period. In the south-western part of Slovakia]. Zoologické listy 1998 one successful nesting was confirmed at the 14: 187–188. [In Czech with English summary] Devínske jazero locality, and in 2012 individuals were Danko Š 2008: Migrácia, zimovanie a hniezdenie my- observed behaving territorially (Moravský Svätý Ján šiarky močiarnej (Asio flammeus) na východnom

Slovensku [Migration, wintering and breeding of the Lengyel J 2006: Krúžkovanie myšiarok močiarnych short-eared owl (Asio flammeus) in eastern Slova- (Asio flammeus) v okolí Nových Zámkov (JZ kia]. Tichodroma 20: 27–39. [In Slovak with Eng- Slovensko) a poznámky k odchytom v rokoch lish summary] 2000–2005 [Ringing of short-eared owls (Asio Danko Š & Chavko J 2002: Myšiarka močiarna (Asio flammeus) in Nové Zámky surrounding (SW Slov- flammeus) [The short-eared owl (Asio flammeus)], akia) and notes to trappings in 2000–2005]. Ticho- 376–378. In: Danko Š, Darolová A & Krištín A droma 1 8: 83–87. [In Slovak with English (eds): Rozšírenie vtákov na Slovensku [Birds distri- summary] bution in Slovakia]. Veda, Bratislava, 668. [In Slov- Mensdorff-Pouilly B 1931: Pustovka v Čechách [The ak with English summary] short-eared owl in the Czech Republic]. Věda Demeter G 2005: Zimný a hniezdny výskyt myšiarky přírodní 12: 167–168. [In Czech] močiarnej (Asio flammeus) v okolí Tekovských Meszáros C, Kotymán L & Kókai K. 2002: Population Lužian (JZ Slovensko) [Winter occurrence and change, habitat selection and prey of short-eared breeding of the short-eared owl (Asio flammeus) in owls (Asio flammeus) in southern Tiszántúl between the Tekovske Lužany area (SW Slovakia)]. Ticho- 1997 and 2002. Aquila 109–110: 109–118. droma 17: 108–110. [In Slovak with English sum- Musílek J 1931: O hnízdění pustovky obecné (Asio mary] flammeus Pontopp.) u nás [Breeding of the short- Dohnal J & Dufek A 1998: Zahnízdění kalousů eared owl (Asio flammeus Pontopp.) in our country]. pustovek (Asio flammeus) na střední Moravě v roce Věda přírodní 12: 169–170. [In Czech] 1998 [Nesting of short-eared owls (Asio flammeus) Noga M 2004: Potrava plamienky driemavej (Tyto alba) in central Moravia in 1998]. Buteo 10: 121–124. [In na Záhorí [The diet of the barn owl (Tyto alba) in the Czech with English summary] “Záhorie” region], 154–155. In: Bryja J & Zukal J Hudec K & Šťastný K (eds) 2005: Ptáci – Aves. Díl (eds): Zoologické dny Brno 2004, Sborník abstraktů II/2. [Birds – Aves. Volume II/2]. Academia, Praha, z konference 12.–13. února. Ústav biologie 581–1204. [In Czech with German summary] obratlovců AV ČR, Brno, 232. [In Slovak] Kněžourek K 1910: Velký přírodopis ptáků se zvláštním Noga 2007: Zimovanie a potravná ekológia myšiarky zřetelem ku ptactvu zemí českých a rakouských. Díl ušatej (Asio otus) na juhozápadnom Slovensku první. [Natural history of birds with special refer- [Wintering and foraging ecology of the long-eared ence to birds of Czech and Austrian countries. First owl (Asio otus) in southwestern Slovakia]. Diplo- volume]. Národní tiskárna I. L. Kobra, Praha, 655. mová práca, Univerzita Komenského, Prírodove- [In Czech] decká fakulta, Bratislava. 102. [In Slovak] Koenig WD & Knops JMH 2001: Seed-crop size and Oláh J, Vasas A 2004: A réti fülesbagoly (Asio eruptions of north American boreal seed-eating flammeus) fészkelési inváziója Magyarországon birds. Journal ofAnimal Ecology 70: 609–620. DOI: 2002-ben [Nesting invasion of the short-eared owl 10.1046/j.1365-2656.2001.00516.x. (Asio flammeus) in Hungary in 2002]. Aquila 2004: König C & Weick F 2008: Owls of the world. Second 111: 89–96. [In Hungarian with English summary] Edition. Christoper Helm, London, 528. Sharikov AV, Volkov SV, Makarova TV, Nikitina LD, Korpimäki E 1984: Population dynamic of birds of prey Sviridova TM & Grinchenko OS 2012: Fenolo- in relation to fluctuations in small mammal popula- gicheskye aspekty biologii ushastoy i bolotnoy sov tions in western Finland. Annales Zoologici Fennici v severnom Podmoskovye [Phenological aspects of 21: 287 – 293. biology of the long-eared and short-eared owls in the Kovács G 2002: Observations on the breeding influx of north Moscow Region], 431–433. In: Gyvrilyuk MN short-eared owls (Asio flammeus) in the Hortobágy (ed.): Birds of prey in the Dynamic Environment of in 2002. Aquila 109–110: 184. the Third Millenium: Status and Prospects. Proceed- Lengyel J 2001: Hniezdenie myšiarok močiarnych (Asio ings of the 6th International Conference on Birds of flammeus) v okrese Nové Zámky v roku 1998 prey and Owls of North Eurasia, Kryvyi Rih, 27–30 a hniezdne výskyty v roku 1999 [Breeding of short- September 2012. Kryvyi Rih Press, 616. [In Russian eared owls (Asio flammeus) in the Nové Zámky dis- with English abstract] trict in 1998 and nest occurrences in 1999]. Buteo Therrien JF 2010: Territorial behavior of short-eared 12: 141–144. [In Slovak with English summary] owls, Asio flammeus, at more than 1000 km north of

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Appendix 1 . Observations of short-eared owls in the Záhorie region (1 997–201 3). D – date, L – locality, no. – the number, N & E – coordinates, O – observers Príloha 1 . Pozorovania myšiarok močiarnych na Záhorí (1 997–201 3). D – dátum, L – lokalita, no. – počet, N & E – súradnice, O – pozorovatelia

D L no. N E O 1 997 Devínska Kobyla 1 48° 1 6’ 1 6° 56’ Noga M ’ 21 . 4. 1 998 Devínske jazero 1 48° 1 6’ 1 6° 56’ Noga M 25. 4. 1 998 Devínske jazero 1 48° 1 6’ 1 6° 56’ Noga M 1 6. 5. 1 998 Devínske jazero 1 48° 1 6’ 1 6° 56’ Noga M 1 6. 5. 1 998 Devínske jazero 1 48° 1 6’ 1 6° 56’ Noga M 1 8.5.1 998 Devínske jazero 1 48° 1 6’ 1 6° 56’ Noga M 3. 6. 1 998 Devínske jazero 2 48° 1 6’ 1 6° 56’ Noga M 5. 2. 2004 Devínske jazero 1 48° 1 6’ 1 6° 56’ Bierbaumer M, Edelbacher K & L 1 4. 11 . 2005 Moravský Svätý Ján min. 6 48° 35’ 1 6° 58’ Noga M 27. 11 . 2005 Moravský Svätý Ján min. 6 48° 35’ 1 6° 58’ Čamlík G 26. 2. 2006 Malé Leváre, Hrubá lúka 2 48° 30’ 1 6° 56’ Čamlík G 1 7. 11 . 2006 Petrova Ves 3 48° 44’ 1 7° 08’ Noga M 26. 11 . 2006 Petrova Ves 1 48° 44’ 1 7° 08’ Noga M 25. 11 . 2007 Stupava, Malý Háj 1 48° 1 6’ 1 6° 58’ Svetlík J 1 9. 1 0. 2008 Devínske jazero 4 48° 1 6’ 1 6° 56’ Noga M 25. 1 0. 2008 Devínske jazero 2 48° 1 6’ 1 6° 56’ Noga M 1 . 11 . 2008 Devínske jazero 1 48° 1 6’ 1 6° 56’ Noga M, Nemček V, Nuhlíčková S 11 . 1 . 2009 Devínske jazero 2 48° 1 6’ 1 6° 56’ Noga M 22. 2. 2009 Devínska Nová Ves 1 48° 1 3’ 1 6° 59’ Václav R 28. 11 . 2009 Petrova Ves 1 0 48° 44’ 1 7° 08’ Noga M, Nemček V, Nuhlíčková S, Svetlík J 5. 2. 2011 Senica 1 48° 40’ 1 7° 22’ Jureček R 1 4. 1 0. 2011 Moravský Svätý Ján 2 48° 35’ 1 6° 58’ Noga M 28. 11 . 2011 Moravský Svätý Ján 2 48° 35’ 1 6° 58’ Noga M 1 3. 1 2. 2011 Moravský Svätý Ján 4 48° 35’ 1 6° 58’ Noga M 1 5. 1 2. 2011 Moravský Svätý Ján 1 2 48° 35’ 1 6° 58’ Noga M, Horal D, Bělka T, Mikusek R 3. 3. 201 2 Moravský Svätý Ján 6 48° 35’ 1 6° 58’ Noga M 6. 3. 201 2 Petrova Ves 1 48° 44’ 1 7° 08’ Noga M 24. 3. 201 2 Skalica 3 48° 51 ’ 1 7° 11 ’ Dobrý M, Madzin J 21 . 4. 201 2 Skalica 3 48° 51 ’ 1 7° 11 ’ Dobrý M, Madzin J 25. 4. 201 2 Skalica 2 48° 51 ’ 1 7° 11 ’ Dobrý M 28. 4. 201 2 Moravský Svätý Ján 2 48° 35’ 1 6° 58’ Svetlík J, Nuhlíčková S 1 2. 5. 201 2 Skalica 1 48° 51 ’ 1 7° 11 ’ Dobrý M 23. 5. 201 2 Skalica 2 48° 51 ’ 1 7° 11 ’ Dobrý M, Chrenková M 20. 1 0. 201 2 Devínske jazero 1 48° 1 6’ 1 6° 56’ Václav R 2. 1 2. 201 2 Studienka, Malacky 1 48° 32’ 1 7° 1 3’ Martinec E 3. 1 2. 201 2 Moravský Svätý Ján 1 48° 35’ 1 6° 58’ Jureček R 31 . 1 2. 201 2 Moravský Svätý Ján 1 48° 35’ 1 6° 58’ Noga M 27. 1 . 201 3 Moravský Svätý Ján 3 48° 35’ 1 6° 58’ Noga M 31 . 1 . 201 3 Moravský Svätý Ján 3 48° 35’ 1 6° 58’ Noga M 1 5. 2. 201 3 Devínska Nová Ves 1 48° 35’ 1 6° 58’ Václav R 28. 3. 201 3 Moravský Svätý Ján 1 48° 35’ 1 6° 58’ Noga M 2. 4. 201 3 Moravský Svätý Ján 1 48° 35’ 1 6° 58’ Martinec E