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  • Author: Dániel Hámori x
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Food composition of the Little Owl (Athene noctua) in a farmland area of Central Hungary, with particular attention to arthropod diversity

Abstract

The feeding of Little Owl (Athene noctua) was studied in a farmland area of Kiskunság, Central Hungary. For the analyses, a total of 661 Little Owl pellets were collected between February and September 2005 from three locations, corresponding known Little Owl territories situated nearby the settlements Apaj, Kunpeszér and Ladánybene. The aim of the present study was to explore the diet composition of Little Owl and to give a detailed evaluation of the arthropod diversity based on the pellet analysis. The identified prey items represented 15 vertebrate and 39 invertebrate species/taxa. In terms of prey number, dominance of small mammals was observed in two sites (Apaj – 55%, Kunpeszér – 68%), while birds and mammals shared almost equal dominance (~25%) in Ladánybene. The most numerous mammal species was the Common Vole (Microtus arvalis), while the Starling (Sturnus vulgaris) played key role among the birds. Contribution of amphibian Common Spadefoot (Pelobates fuscus) was considerable, while share of reptiles was marginal. Vertebrates also played a predominant role by contributing over 99% of the overall prey biomass in all study sites. Invertebrate prey dominance ranged from 24.8–30.0% while their contribution to the overall biomass was very low (0.14–0.34%). Large sized beetles (Pentodon idiota, Melolontha hippocastani) and orthopterans (Tettigonia viridissima, Gryllotalpa gryllotalpa) were preferred. Arthropod species richness and diversity were the highest in Kunpeszér, supposedly owing to the rich mosaic habitat structure.

Open access
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.

Open access
Little Owl’s (Athene noctua) vertebrate food composition during breeding season with high frog dominance in grasslands

Abstract

The aim of our study was to investigate the feeding of the Little Owl (Athene noctua) during the breeding period in three protected sites (Upper Kiskunság Puszta, Upper Kiskunság Lakes, Peszéradacs Meadows) in an extensively managed lowland plain area (Upper Kiskunság) of the Carpathian Basin. A further objective was to provide a detailed assessment of the vertebrate prey spectrum and dominance structure based on the analyses of pellets. Little Owl pellets were collected in September 2015 and 2016 from 20 artificial nest boxes in which successful breeding occurred in both years. Mean pellet number was calculated per individuals. Distribution of individual number and biomass of vertebrate prey taxa were also examined. The number of collected and dissected owl pellets was 2,094 in 2015 and 2,024 in 2016, respectively. The average rate of pellet regurgitation was 25.57 pellets/ind. in 2015, and 27.74 pellets/ind. in 2016. From the 40 samples (4,118 owl pellets) a total of 2,017 vertebrate preys were determined. Cumulative species richness was 21, including 12 mammalian, 1 amphibian, 4 reptile and 4 bird species. Mammals were dominant in the food (average 50.83%), and the consumption of amphibians was similar (48.06%). The consumption of birds and reptiles was not significant. Amphibians were represented by a single species, the Common Spadefoot (Pelobates fuscus) in remarkably high proportions among the prey items, followed by the Common Vole (Microtus arvalis) by approx. 37% proportion. The high proportion of the latter two species was also clearly reflected in the biomass amounts. Among the birds, the Starling (Sturnus vulgaris) proved to be the most commonly predated species apart from other species closely related to farmland habitats (Motacilla alba, M. flava, Passer montanus).

Open access