Tichodroma (Dec 2016)
Owl breeding survey in the lower part of the Ipeľ River basin (S Slovakia), 2010–2016 / Sovy hniezdiace v južnej časti Ipeľskej kotliny (J Slovensko) v rokoch 2010 – 2016
Abstract
European farmland habitats face dramatic changes in biodiversity and birds serve as good indicators of such changes. Here I present results of a seven-year survey for a particular group of farmland birds, owls, for a region in southern Slovakia during 2010–2016. The ecological abundance of Scops-Owl, a focal owl species, was 3–5 breeding territories/40 km of the Ipeľ River. Approximately half (6/11) of Scops-Owl territories was located in old rural parks within villages, with the remaining territories being located in riverine woodland. A high availability of large trees and extensive grassland areas with low pesticide use appear to provide Scops-Owl with the most suitable breeding habitats within the study area. With an estimated median breeding population density of 4 (range: 1–7) pairs per ca. 80 km2 , Long-eared Owl breeding density in the study area belongs among Slovakia’s highest. Most Long-eared Owl breeding territories were located in villages in various woodland structures, such as old manor and cemetery parks, street tree lines and windbreaks, with the remaining territories being located in similar structures, mainly hedgerows, but just outside the villages. Little Owl breeding distribution was limited to a single breeding core area, consisting of four breeding territories. The median breeding population density of Little Owl was 2 (range: 0–4) pairs per ca. 80 km2, with the median ecological breeding density being 1 (range: 0–4) pair per ca. 4 km2 . Four Tawny Owl breeding territories were recorded, and two of these territories overlapped with those of Scops-Owl. Single breeding territories of Barn Owl and Eagle Owl were recorded. The current distribution of Barn Owl and mainly Little Owl emphasizes the importance of ruderal and non-productive farmland habitats and indicates important changes in trophic interactions in the region’s farmland ecosystem.
