Abstract
We completed data on the diet of the barn owl (Tyto alba) predominately from pellets for the period of the last 50 years from Slovakia. We analyzed material from 251 locations and 16 territorial units. The aggregate represents 119,231 pieces of prey from 47 species of mammals (Mammalia, 95.7%) and 58 species of birds (Aves, 3.9%), with a small representation of amphibians, reptiles (Amphibia and Reptilia, 0.2%) and invertebrates (Invertebrata, 0.2%). The obtaining of food among the owls is limited to synanthropic environments and the surrounding agricultural landscape, and the centre of its distribution in the recent period (i.e. the past 50 years: 1965-201 5) has been concentrated mainly on the southern parts of Slovakia. In this environment the common vole (Microtus arvalis, 59.6%) is the primary prey. Additional prey are rodents of the family Muridae: Mus musculus (5.6%), Micromys minutus (2.2%), Apodemus microps (2.2%), A. flavicollis (2.0%), A. sylvaticus (1 .6%) and A. agrarius (1 .5%); insectivores of the family Soricidae: Sorex araneus (6.2%), S. minutus (2.4%), Crocidura leucodon (4.8%) and C. suaveolens (2.8%); and the house sparrow Passer domesticus (2.9%). In the higher situated Turcianska kotlina Basin the species M. arvalis (74.3%) has higher domination, and instead of the white-toothed shrews the water shrews Neomys anomalus (2.8%) and N. fodiens (1 .3%) are more abundantly represented. In 3 localities owls focused on hunting bats; for example, in the church in Ratková the order Chiroptera made up 35.2% of prey. From the subrecent period (i.e. from before more than 50 years ago) we evaluate 4 samples from the territory of Slovakia with 15,601 pieces of prey ofT. alba. Before more than 50 years ago owls were also more abundantly represented at higher elevations in Slovakia, evidence of which is Weisz’s collection of pellets from 1 6 localities in the Ondavská vrchovina Upland in the years 1945 to 1963, but also a registry of data from the 19th and 20th centuries from higher located basins. In 4 samples of food from the subrecent period diversity in the representation of owl prey is higher, accompanied by low domination ofM. arvalis and a more abundant representation of murids from the genera Mus and Apodemus. The oldest sample, dated to the 16th century, is from a church in Žilina-Rudiny
Overcompensation and phase effects in a cyclic common vole population: between first and second-order cycles