Seasonal variation of small mammals in the diet of the barn owl (Tyto alba) in the Drinos River valley, southern Albania

Abstract

The small mammal composition in the diet of barn owls from the Drinos River valley, southern Albania, was studied over the period of 1 year (September 2010-September 2011). A total of 662 pellets was collected and analyzed, and 1951 prey items were identified. Fourteen different small mammal species were identified (5 insectivores and 9 rodents), among which Microtus thomasi (frequency, F = 32.9%; biomass, B = 45.5%), Crocidura suaveolens (F = 23.5%; B = 9.4%), and Mus macedonicus (F = 17.8%; B = 16.3%) were the most abundant. In winter, Rattus rattus increased significantly in the consumed prey biomass (18.1%), while in spring Apodemus sylvaticus (9.4%) ranked third most common among the prey species. Neomys anomalus was more frequent in the diet in autumn and winter than in spring and summer. Suncus etruscus had low percentages in the barn owl diet, but was preyed upon during all seasons, confirming the presence of the species in the Drinos valley. Significant seasonal variations in small mammals in the diet of the barn owl were detected. Environmental index (i/r) values indicate that the Drinos valley is mainly an agrocenosis of nonintensive land-use practices.