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Slovak Raptor Journal 2011, 5: 121–126. DOI: 10.2478/v10262-012-0058-7. © Raptor Protection of Slovakia (RPS) The abundance of the little owl (Athene noctua) in Podunajská rovina lowland in 2009 and 2010 Početnosť kuvika obyčajného (Athene noctua) na Podunajskej rovine v rokoch 2009 a 2010 Martin DOBRÝ Abstract: This paper outlines the results of the mapping of the little owl and its abundance in selected areas in Podunajská rovina lowland, Slovakia, in 2009 and 2010. From a total area of 3,500 km2, 11.6% was monitored and 26 occupied localities identified. Average abundance was 0.6 occupied localities per 10 km2. Abstakt: Práca informuje o výsledkoch mapovania výskytu kuvika obyčajného na území vybraných častí Podunajskej roviny v rokoch 2009 a 2010. Z celkovej rozlohy Podunajskej roviny (3500 km2) bola zmapovaná plocha približne 11,6 %, kde bolo zistených 26 obsadených lokalít. Priemerná abundancia bola 0,6 obsadených lokalít na 10 km2. Key words: population density, distribution, Slovakia. Martin Dobrý, Raptor Protection of Slovakia, Kuklovská 5, SK–841 04 Bratislava 4, Slovakia. E-mail: [email protected]. Acknowledgement: I thank Ivan Dobrý, Zuzana Kesanová, Roman Kormoši and Zoltán Vozák for their help with the field work. Special thanks go to Marcel Uhrin for his encouragement. The study was supported by the grant scheme of the Small Member Projects 2010 of the Raptor Protection of Slovakia and by the European Regional Development Fund within the Slovak-Austrian cross-border cooperation programme 2007–2013 (project CORO-SKAT N00103). Introduction and strengthen populations within Slovakia, are ongoing. Populations of the little owl in Central Europe have de- The most common causes of the decline include the be creased significantly over the last 50 years, much more loss or unavailability of trophic sources, loss of breeding so than for any other owl species (Glutz von Blothzheim and day roosting sites, direct human disturbance at nests, & Bauer 1994). In Germany, a population decline of 24% collisions with vehicles, severe winters with long-lasting and in Poland 50% (Nieuwenhuyse et al. 2008) were not- snow cover, predation pressure and a significant number ed between 1994 and 2004. Decreasing populations in of owls also perish when trapped in drainpipes, chimneys the Czech Republic and in large unoccupied areas in the and the like (Šťastný et al. 1987, Sedláček 1988, Schönn north of Slovakia have, in recent years, shown that little et al. 1991, Glutz von Blotzheim & Bauer 1994, Hage- owls in the lands of the former Czechoslovakia are also meijer & Blair 1997, Pačenovský 2002, Závalský 2004, under continued pressure. Compared with the beginning Nieuwenhuyse et al. 2008). of the millennium, in 2011 further declines in populations The main aim of this study was to estimate the popu- in open agricultural land in the Czech Republic were also lation size of the little owl in the south-west of Slovakia, found. This negative trend in abundance is also apparent based on the results recorded in selected parts of Podunaj- from “distribution centres“, where the little owl used to ská rovina lowland, and to contribute to the knowledge of attain relatively high population density rates. The pre- overall abundance of the species in Slovakia. sent population of the little owl in the Czech Republic does not exceed 180 breeding pairs (2010–2011; Šálek Study area & Schröpfer 2011, pers. comm.). The absence of up-to- Podunajská rovina lowland, with the exception of a small -date data on the abundance and number of the little owl in area in the north-west, is one of the driest and warmest Slovakia, has prompted a renewed interest in the species. climatic zones in Slovakia. In the north of Podunajská Identifying the key areas of abundance and setting up rovina lowland, the influence of the Malé Karpaty Mts. is adequate protection measures for this owl, in order to save apparent and causes the climate to be slightly more humid 121 Dobrý M: The abundance of the little owl (Athene noctua) in Podunajská rovina lowland in 2009 and 2010 and colder than the rest of the region. The warmest area Material and methods lies around Veľký Meder, where the average annual tem- Data were gathered on four model areas in Podunajská perature is more than 10 °C. In other parts of Podunajská rovina lowland with the overall area of 406.9 km2 (Figure rovina lowland, the average annual temperature does not 1) during spring seasons (from March 10 to May 9) in the exceed this figure. The average air temperature in January years 2009 and 2010. A standardised method of mapping is usually -1 °C to -2 °C, in July it is more than 20 °C. was used with the help of territorial call recordings, which Annual rainfall reaches 600 mm, while approximately were played from a car radio. Mapping was carried out 300–350 mm falls during the growing season (Veľký after sunset (earliest time just after dusk) to approximately 1980). The most important element in land structure in 23:00. Three minutes of playing recordings were followed the model areas is arable land, which comprises 57.5% by two minutes of listening. Recordings were then played to 80.1 % of the whole territory. The remainder is com- once more for two minutes. If there were no responses posed of vineyards, gardens, orchards, grasslands, forests, from little owls after another five minutes of listening, water surfaces, built-up areas and the other surfaces, with the area was considered unoccupied. Farmyards were relatively equal representation (ÚGKK SR 2010). The not visited directly, rather recordings were only played typical land-use of Podunajská rovina lowland is depicted close by. Some areas were checked in both of the years in Figure 2. the mapping took place. An area where the species was Fig. 1. Location of model areas in the southwest of Slovakia. 1 – residence/settlement/site, 2 – geographic unit boundary, 3 – model area 1, 4 – model area 2, 5 – model area 3, 6 – model area 4. Obr. 1. Poloha modelových plôch v rámci juhozápadného Slovenska. 1 – sídlo, 2 – hranica geografického celku, 3 – modelová plocha 1, 4 – modelová plocha 2, 5 – modelová plocha 3, 6 – modelová plocha 4. 122 Slovak Raptor Journal 2011, 5: 121–126. DOI: 10.2478/v10262-012-0058-7. © Raptor Protection of Slovakia (RPS) found in at least one year, was considered occupied. When Results a little owl responded, the recording was terminated at Out of 79 controlled areas, 26 were occupied in at least one once and the area considered occupied. Field work was of the mapping years. The overall proportion of occupied done only in favourable weather conditions (without rain areas was 32%. The abundance of the species was record- and wind). ed in individual model areas 0.2 (model area 3), 0.4 (4), Agricultural areas (Figure 2), farms, isolated buildings 0.7 (1) and 1.2 (2) in occupied locality per 10 km2. The in farmland and other closed areas, occasionally also ce- average abundance was 0.6 occupied localities per 10 km2. meteries, castles, parks and ruins, were all mapped. A total The highest value was recorded in model area 2, on Žitný of 79 localities were checked. The overview of cadastral ostrov, the boundaries of which are formed by cadastral districts composing the model areas is in the Table 1. area Janíky in the north, Oľdza in the east, Kvetoslavov in the south and Miloslavov in the west. In this region two cadastral areas lacked positive records. In model area 1, Tab. 1. Overview of model areas and numbers of monitored and around the town of Šaľa, the abundance rate was 0.7 of occupied sites. 2 Tab. 1. Prehľad mapovaných plôch a počtov kontrolovaných an occupied area per 10 km and one cadastral district a obsadených lokalít was without a positive response. The model area 3 with the lowest abundance rate and only one positive locality the number of surveyed / was situated on the outskirts of Bratislava. The highest cadastral district / occupied sites rate of two occupied areas per one cadastral district was katastrálne územie počet kontrolovaných / obsadených lokalít recorded 6 times, one occupied area per a cadastral dis- area / plocha 1 [153.9 km2] 27 / 10 trict was registered fourteen times and in eight cadastral Diakovce 3 / 1 districts the presence of the species not confirmed at all. Kráľová nad Váhom 3 / 2 All localities with positive occurrence were of anthropic Tešedíkovo 2 / 2 character – agricultural areas. Occurrence in parks, gar- Žihárec 3 / 2 dens and in open land was not confirmed. Šaľa 7 / 0 Podunajská rovina lowland covers more than Dlhá nad Váhom 2 / 1 3,500 km2, of which the mapped area comprised Topoľnica 3 / 1 406.9 km2 (11.6%). Based on the results from this area Kajal 4 / 1 in the years 2009 and 2010, it is possible to estimate the area / plocha 2 [83.7 km2] 26 / 10 total number of sites occupied by the little owl as appro- Štvrtok na Ostrove 2 / 1 ximately 217. Čakany 1 / 0 Dolné Janíky 1 / 0 Discussion Horné Janíky 2 / 1 Due to the use of indirect detection methods to establish Hubice 3 / 1 the little owl population size, it is necessary to consider Oľdza 2 / 1 the assessment of the population in the area as relative Mierovo 2 / 1 (Townsend et al. 2008). Between 800 to 1,000 pairs of Kvetoslavov 4 / 1 Hviezdoslavov 7 / 2 little owl were estimated in Slovakia in 2002 (Pačenov- Miloslavov 2 / 2 ský 2002), a figure which corresponds well with the 217 area / plocha 3 [44.1 km2] 7 / 1 occupied localities in Podunajská rovina lowland in 2009 Rusovce 4 / 1 and 2010.

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