Spatial and temporal patterns in the diet of barn owl (Tyto alba) in Cyprus

Abstract

BackgroundThe barn owl, a nocturnal raptor with cosmopolitan distribution, shows a great adaptability to different environments. Regarding prey, the barn owl is a rather selective species, but if changes in the abundance of the selected prey occur, it becomes an opportunistic predator and easily incorporates other prey in its diet, using a wide range of prey species and foraging habitats. Small rodents are usually the prey mostly used. Compared to the populations of north and eastern Europe, barn owl populations in the Mediterranean area have been the least studied. In Cyprus, where barn owl is a common bird species, there are no studies on its diet and feeding ecology. This study was carried out to contribute to the spatial and temporal patterns barn owl diet in Cyprus also providing information on small mammals’ presence and species composition on the island.MethodsThis study was based on 1407 regurgitated pellet analysis that were collected from 26 sites representing six major habitat types on central and southern Cyprus from summer 2013 to summer 2014. The diet of the barn owl was described in terms of seasonal average biomass and numerical percentages of each prey species and compared by Kruskal–Wallis test. Seasonal prey diversity and evenness indices were also calculated. Principal component analysis (PCA) was performed on the prey biomass proportion data assigned to six major habitat types with regard to elevation, vegetation and human uses.ResultsLow prey diversity was found comprised mainly of rodents (overall means 96.2 and 95.7% by number and biomass, respectively). Mice followed by rats were most important prey whereas insectivores, birds and insects were minor components of the owl’s diet. Evenness and diversity values were relatively similar among seasons. PCA differentiated mainly between lowland areas where mice were more abundant prey and mountainous areas where rats dominated in the diet. Insectivores correlated with birds, prey types characterizing several lowland and highland habitats.ConclusionsThe barn owl prey composition in Cyprus suggests an opportunistic foraging behavior, low prey species diversity with variations in the main rodent prey that could be explained by their distribution, seasonal activity and habitat preferences.

Investigating the relationship between the prey composition of Barn Owls (Tyto alba) and the habitat structure of their hunting range in the Marcal Basin (Hungary), based on pellet analysis

“…For this reason, we should try to collect samples from the study area for as many years as possible, with seasonal frequency (Fehér & Fehér 2004). The limitations of the usability of this method are also influenced by the fact that owls hunt not only within the assumed hunting range, and are likely to prefer more accessible species (Moysi et al 2018). We suggest improving the efficiency of the method by using finer structure of the landscape and more precise definition of habitats.…”

Winter diet of Long-eared Owls (Asio otus) in the southern Pannonian Plain (Serbia, Vojvodina)

“…1 The diet preferences of raptors with a broad range of distribution, shows spatial differences based on prey availability as a consequence of diverse environmental conditions and human activity within their hunting territories. [2][3][4][5][6] Korpimäki and Marti 7 explained that many raptors (Falconiformes and Strigiformes) are highly opportunistic in the prey they consume, and their diet thus reflects the distribution pattern of their prey. The winter diet of many raptors' species is wellstudied and shows several spatial differences in contrast with the breeding diet.…”

Large-scale spatial patterns of small-mammal communities in the Mediterranean region revealed by Barn owl diet

“…Discussing it, first we should remember the incipient qualities which promote the cosmopolitan distribution of the Barn Owl—its feeding in open grounds and semi-opened habitats and greatly pronounced capability of opportunistic foraging modifying its diet in response to actual availability of local prey 44 , 45 , 56 . Correspondingly, in the Mediterranean, the local appearance of Barn owl is clearly confined to the sites providing both suitable nesting possibility (cave entrances and niches in rocky massifs, abandoned human constructions) and foraging ground rich in a mosaic of semi-opened and open habitats hosting abundant communities of small mammals 56 . It seems that owl foraging is restricted to such habitats even in the localities where urban or farmland habitats, forests or wetlands compose the predominant landscape components.…”

“…In contrast to expensive and time-consuming conventional trapping (snap traps, live traps or pitfall traps) 50,51 , which is biased by the absence of some trap-shy species (such as Muscardinus avellanarius or Suncus etruscus) 52 or incomplete time and habitat coverage, the owl pellet analyses provide a reliable assessment of taxonomic structure and abundance of prey communities which is well balanced both in spatial and temporal respects 43,47,48,[53][54][55] . The long-term studies on Barn owl diet performed within the Mediterranean 45,56 show relatively small seasonal and annual variation, though locally, it may be influenced by temporal fluctuations in prey availability and ad hoc variations in foraging tactics of individual owl 45 . It can be however expected that such a kind of variation may appear in particular sites with roughly equal probability and related biasing influences can be effectively reduced by increasing sample sizes, which was applied in our study.…”