Effects of a forest landscape on the prey composition of the Common Barn-owl Tyto alba in southern Bulgaria

Abstract

The diet of the Common Barn-owl in a forest- and shrub-dominated hunting area in the Strandzha Mountains, southern Bulgaria, was identified from 516 prey specimens. Shrews (52.9% by number, 26.7% by biomass) and rodents (42.1% N, 71.5% B) were prevalent. Among them, White-toothed shrews, Criocidura sp., (45.3% N, 21.4% B) was the most numerous prey genus. Mice, Apodemus sp., (15.7% N, 29% B) contributed with the largest share to the food biomass due to high predation of Striped field mice, A. agrarius, (12.2% B). The proportions of forest species in diet (Apodemus sp, Sorex sp., and dormice liridae) increased with the higher proportion of forest habitats (forests and shrublands cover more than 25% of the area) in most Barn Owl hunting territories in southern Bulgaria.

Variation in small mammal food resource niche metrics of Western Barn Owl (Tyto alba) at the nesting pair and local population level

“…Studies on feeding habits and trophic niche breadth, and overlap variation of the Western Barn Owl at the level of intra-and interspecific feeding ecology are well known from several literature sources along its European (Pezzo & Morimando 1995, Bontzorlos et al 2005, Kitowski 2013, Petrovici et al 2013, Milchev 2016, North American (Marsk & Marti 1984, Marti et al 1993, Jiménez et al 2020, and South American (Trejo et al 2005, Nanni et al 2012 distribution range in temperate ecosystems. It is important to highlight the studies that evaluated the trophic niche pattern of the Western Barn Owl based on geographical variation or trends (Korpimäki & Marti 1995, González-Fischer et al 2011, Milana et al 2016, or along different gradients such as vegetative (Trejo & Lambertucci 2007), longitudinal-latitudinal (Leveau et al 2006), and urban-rural (Teta et al 2012, Hindmarch & Elliott 2015 gradients or in comparison of different landscape structures (Milchev 2015(Milchev , 2022, focusing on the importance of agricultural intensification in the resource utilization of Barn Owls (Veselovský et al 2017, Horváth et al 2018, Romanowski & Lesiński 2020, Jiménez-Nájar et al 2021. Moreover, golypopuláció niche szélessége szignifikánsan nagyobb volt az összeomlás időszakban.…”