Demographic data on the Little Owl(Athene noctua)in Upper-Kiskunság (Hungary)

Abstract

This study focused on the clutch size and age-specific apparent survival rate of the Little Owl (Athene noctua) population in Upper-Kiskunság, Hungary. Between May 2005 and April 2017, 640 individuals were captured and ringed in a total of 746 capture-recapture occasions. Artificial nest boxes were installed in the study area, breeding birds and pulli were captured for ringing/recaptured in these boxes (from March to May), or at the close neighbourhood of those (max. 168 m). Jolly-Seber's open population method was applied to model the survival rate. The candidate model set included models incorporating age, year-effect, and the combination of those. AICc value was used to compare models in a selection approach. The final model was constructed via model averaging based on the models with significant explanatory power. The average number and SD of pullus/breeding pair was 3.78 ± 0.76. The average apparent annual survival rate (which does not differentiate between mortality and permanent emigration) for the period between pullus stage and the time of the first breeding was estimated as 9.47% ± 2.99% SE, whereas the annual survival rate of adults was 82.74% ± 8.46% SE. The effect of sex on the survival rate of adults was not investigated due to female-biased sample, as the probability of capturing females is significantly higher in late spring months. Our experience reveals that during February and March it is possible to capture both sexes in the nest boxes, and it does not influence negatively the breeding success. Based on our results, the population of the Little Owl is stable in Upper-Kiskunság. A slight increase in estimated population size is observable even if we make no difference between mortality and permanent emigration. The high occupancy rate of the installed nest boxes reveals that nest site availability is an important limiting factor in the studied population.Keywords: owl conservation, ringing data, age specific survival rates, Strigiformes, Hungary Összefoglalás Vizsgálatainkkal a kuvik (Athene noctua) felső-kiskunsági populációjára jellemző átlagos fészek-alj-méretet, valamint a korspecifikus, éves túlélési rátákat kívántuk meghatározni. A 2005 májusa és 2017 áp-rilisa közötti időszakban a Felső-Kiskunságban 640 egyedet fogtunk meg, a visszafogásokkal együtt összesen 746 alkalommal. A madarak fémgyűrűvel történő jelölése és visszafogásaik első sorban a vizsgálati területre kihelyezett mesterséges kuvikodúkban (március-június), vagy azok 168 méteren belüli környezetében történtek. A fogás-visszafogási adatokat nyílt populációs Jolly-Seber módszerrel elemeztük, az alternatív modellekben az egyedek túlélését magyarázó tényezőként a korcsoportot, az évhatást, valamint ezek kombinációját szerepeltettük. A modellek összehasonlítására az AICc értékeket használtuk, a szignifikáns magyarázóerővel bíró alternatív modellek átlagolásával állítottuk elő a végleges modellt, illetve annak paraméter értékeit. A vizsgált populá-cióban az átlagos fészekalj-méret 3,78 ± 0,76 SD fióka/fészek volt. Az átlag...

The status and population changes of the Little Owl(Athene noctua)in the south of Békés county (Hungary)

“…Our results highlighted that not the food source, but the availability of breeding sites will be the limiting factors for the local population in the future (see also Hámori et al 2017). Compared with the data from 2007, many houses and outbuildings used for nesting formerly collapsed and became unsuitable for nesting by 2017.…”

Analysis of skull morphometric characters in Owls (Strigiformes)

“…-A: feeds primarily on arthropods, for example Eurasian Scops Owl (Otus scops) (Kadochnikov 1963, Galeotti & Sacchi 2001, Lee & Severinghaus 2004) -B: species feed on arthropods and vertebrates, for example Little Owl (Athene noctua) (Glue & Scott 1980, Laursen 1981, Hounsome et al 2004, Šálek et al 2013, Hámori et al 2017, Northern Hawk Owl (Surnia ulula) (Nybo & Sonerud 1990, Sonerud 1986, 1992). -C: feeds exclusively on vertebrates, for example Great Eagle Owl (Bubo bubo) (Papageorgiou et al 1993, Penteriani et al 2002, Milchev & Spassov 2017, Barn Owl (Tyto alba) (Milchev 2015, Horváth et al 2018)…”