An attempt to determine the size of the Common Barn-owl’s (Tyto alba) hunting area based on its prey composition

2021 ◽  
pp. 175815592110660
Author(s):  
Jenő J Purger ◽  
Dávid Szép

The relative abundance of small mammal species detected from Common Barn-owl pellets reflects the landscape structure and habitat pattern of the owl’s hunting area, but it is also affected by the size of the collected pellet sample and the size of the supposed hunting area. The questions arise: how many pellets should be collected and analyzed as well as how large hunting area should be taken into consideration in order to reach the best correspondence between the owl’s prey composition and the distribution of habitats preferred by small mammals preyed in supposed hunting areas? For this study, we collected 1045 Common Barn-owl pellets in a village in southern Hungary. All detected small mammal species were classified into functional groups (guilds) preferring urban, open, forest and wetland habitats. The proportion of functional groups was compared to the proportion of these habitats around the pellet collection site within circles of one, two, and three km radius. Saturation curves showed that at least 300 pellets or ca. 600 mammalian remains are required for the detection of the 19 small mammal species. The share of small mammals detected in the prey and their functional groups according to their habitat preference showed an increasing consistency with the distribution of real habitats in the potential hunting area of a radius of 3 km around the owl’s breeding or resting place.

2019 ◽  
Vol 27 (1) ◽  
pp. 32-43
Author(s):  
Dávid Szép ◽  
Ákos Klein ◽  
Jenő J. Purger

Abstract Little was known about the small mammal fauna of the Marcal Basin to date, therefore we collected 1,144 Barn Owl pellets from 15 locations in 2017. After the analysis of the pellets, remnants of 3,063 prey items were identified, of which 97.5% were small mammals, belonging to 21 species, while the remaining 2.5% were birds, frogs and insects. Mammal prey items consisted of Cricetidae 41%, Muridae 31% and Soricidae 28%, and in some samples, we found the remnants of European Mole (Talpa europaea), Kuhl’s Pipistrelle (Pipistrellus kuhlii), Hazel Dormouse (Muscardinus avellanarius) and Least Weasel (Mustela nivalis). Small mammal species were classified into four functional groups based on their preferences for urban, open, forest or wetland habitats. We investigated whether their relative abundances match with the proportions of the four habitat types in the assumed Barn Owl hunting ranges (cca. 2 km radius circle) in five sample sites. The relative abundance of small mammal species preferring urban habitats showed concordance with the proportion of the appropriate habitat types in the hunting area in two samples, while such concordance was proved for species favouring open, forest and wetland habitats just in one out of five samples. Small mammal functional groups represented in the prey composition do not directly correspond to the proportion of their typical habitats. We conclude that the abundance of various prey types is not suitable for characterising the landscape within the Barn Owl’s hunting range.


2017 ◽  
Vol 25 (2) ◽  
pp. 51-64
Author(s):  
Dávid Szép ◽  
Ákos Klein ◽  
Jenő J. Purger

Abstract The prey composition of the Barn Owl (Tyto alba) can be monitored indirectly by pellet analysis and we used this method to investigate less known small mammal species of Zala County. The number and abundance of small mammal species depend on the structure of the landscape of Barn Owls’ hunting area, therefore we analysed landscape features in the surrounding circles with 2 km radius around the sampling sites. In 2016 we collected 1106 pellets from 13 sampling localities. From the pellets we identified 21 species of 3022 individuals of small mammals (more than 98% of prey). Among the 21 species there was the rare Parti-colured Bat (Vespertilio murinus) and a new species for the county the Steppe Mouse (Mus spicilegus). Positive correlation was found between the diversity of the small mammal fauna of each sampling site and the landscape complexity (number of the landscape patches) of the Barn Owl hunting area. Relative abundance of the Wood Mouse (Apodemus sylvaticus) showed positive correlation with the number of landscape patches, while the abundance of the Lesser White-toothed Shrew (Crocidura suaveolens), the Miller’s Water Shrew (Neomys anomalus), the Striped Field Mouse (Apodemus agrarius) and the Harvest Mouse (Micromys minutus) was higher in hunting areas with more homogenous landscapes. Significant correlations were found between the relative abundance of some small mammal species and the landscape structure of the potential hunting area of owls that confirmed the consistency in habitat preference of some species. Our results proved that the prey-composition of Barn Owls reflects the land use through the distribution and abundance of small mammal species, therefore this method is suitable for ecological analyses of landscape.


1989 ◽  
Vol 16 (6) ◽  
pp. 611 ◽  
Author(s):  
JDB Smith ◽  
J Cole

The diet of the barn owl was determined by analysing egested pellets collected from the Tanami Desert. These data were also used to examine the distribution of small mammals in the region. Rodents were the dominant prey items, forming more than 74% of prey biomass in all samples. The dominant rodent species were those that undergo large fluctuations in population size. Notomys alexis was the dominant prey item in 15 of the 17 samples. In all samples, one or two species of rodents formed 47-100% of prey biomass. Dasyurids were relatively minor prey items, forming less than 12% of prey biomass in all samples. It is suggested that this is a reflection of their abundance relative to rodents. Bats, birds, lizards and insects combined formed less than 14% of prey biomass in all but one sample (24%). Behavioural and life-history characteristics of prey appear to affect their susceptibility to predation. The analysis of pellets proved to be a useful supplementary technique to conventional methods of surveying small mammals. All species of small mammal that could be expected were identified in owl pellets. Notomys amplus was recorded in pellets but not collected by conventional techniques.


1988 ◽  
Vol 66 (8) ◽  
pp. 1803-1812 ◽  
Author(s):  
Carl D. Marti

Food niches of Common Barn-Owl (Tyto alba) populations were studied for 8 years in Utah and Idaho. Small mammals dominated the diet as they do in most parts of the barn-owl's range. Mean prey weight was nearly identical between the two owl populations. Food-niche breadth, though, was significantly broader in Idaho than in Utah. Food-niche breadth was also more variable in Idaho than in Utah both within and between years. Voles (Microtus spp.) were predominant prey for both owl populations and were the only prey whose numeric variation in the diet significantly affected mean prey weight and food-niche breadth. Vegetative composition was less varied and more uniformly favorable to voles in Utah. The Idaho area contained a smaller poportion of good vole habitat but had a greater diversity of vegetation including deserts suitable for small mammal species not found in the Utah study area. These vegetative differences and their effects on small mammal species diversity and density were the most apparent causes of food-niche differences between the two owl populations.


Author(s):  
Zoya Selyunina ◽  
Yuriy Moskalenko

The barn owl (Tyto alba) formerly was one of the rarest vagrant bird species in the Black Sea Biosphere Reserve. Since 2018, this species has been wintering regularly in the Yahorlytskyi Kut division of the Black Sea Biosphere Reserve. We studied the barn owl’s diet in the reserve by analysing 20 pellets collected in the winter of 2018. A total of 69 specimens of 5 mammal species were identified from the pellets. Species of small mammals that dominate in open habitats prevail in the barn owl’s diet such as the social vole (Microtus socialis) (dominant species of steppe habitats; 43 % of identifiable small-mammal specimens) and the lesser white-toothed shrew (Crocidura suaveolens) (dominant species of salt marsh habitats; 42 % of identifiable small-mammal specimens). Remains of the southern vole (Microtus levis), the Ural field mouse (Sylvaemus cf. uralensis), and the Eurasian pygmy shrew (Sorex minutus) were non-abundant in the barn owl’s diet.


2020 ◽  
Vol 39 (3) ◽  
pp. 260-269 ◽  
Author(s):  
Ivan Baláž ◽  
Martina Zigová

AbstractThe landscape of south-western Slovakia is characterised by anthropogenous reshaping, while fragments of undisturbed, waterlogged habitats have been preserved in what remains of the meandering ancient Žitava River. These refuges are inhabited by various small mammal species and their blood-sucking ectoparasites. Between 2014 and 2018, research on them was carried out in Slovakia’s Danubian Lowland (Podunajská nížina) during three out of the four seasons (spring, summer and autumn). The small mammals were captured at 27 localities. The occurrence of nine flee species from the Hystrichopsyllidae, Ctenophthalmidae and Ceratophyllidae families was documented on 12 small burrowing mammals. During the course of all the seasons in which research was conducted, Ctenophthalmus agyrtes, C. assimilis, Megabothris turbidus a Nosopsyllus fasciatus were found, among the most dominant species to be seen on small burrowing mammals.


Biologia ◽  
2013 ◽  
Vol 68 (1) ◽  
Author(s):  
Zuzana Poláčiková

AbstractThis study deals with the species distribution and structure of mite communities living in the fur of small mammals. Mesostigmatic mites (Acarina: Mesostigmata) of several small mammal species were studied at several sites of Slovakia situated in the Podunajská nížna lowland. The aims deal with ecological evaluation of mesostigmatic mites and their small mammal hosts. The research was done from 2005 to 2007. Several small mammal species were caught at 16 sites in the research area. These represent 13 types of biotopes. On the captured small mammals we recorded 3,141 individuals of mesostigmatic mites (7 families and 22 species). The dominance and the diversity of the recorded mites were analysed. Mites being interpreted as the variable one were evaluated by cluster analysis and multifactor analysis (detrended correspondence analysis, principal components analysis, redundancy analysis). Small terrestrial mammals as hosts of mites represent “holders” of environmental factors, in the analysis they are being evaluated as explanatory variable mainly. They transform direct impact of the environment and for that reason the ecological evaluation of mites is specific comparing to other taxonomical and ecological groups of animals.


2019 ◽  
Vol 46 (8) ◽  
pp. 690 ◽  
Author(s):  
Helen P. Waudby ◽  
Sophie Petit ◽  
Matthew J. Gill

Abstract ContextTrapping design influences information collected about wildlife populations and biodiversity. Trapping is also resource-intensive and has animal welfare implications. AimsThe scientific, financial and ethical performances of three trap designs were compared for estimating diversity and sampling small vertebrates. MethodsSmall vertebrates were trapped over 16 trapping sessions, from April 2009 to May 2011, with aluminium box-style (Elliott) traps and two pitfall trap designs (shallow–wide and deep–narrow), in an arid environment. Key resultsShallow pitfalls recorded highest overall species richness (S=22) and diversity (qD=10.622), reptile diversity (qD=8.112) and reptile capture rates (13.600 individuals per 100 trap nights). Shallow and deep pitfalls sampled ~79.0% and 85.0% (respectively) more small mammals than did Elliott traps. Deep pitfalls sampled the greatest diversity (qD=6.017) and number (29.700 individuals per 100 trap nights) of small mammals, and captured the greatest number of small mammal species (0.003) and individuals (0.106) per dollar. Shallow pitfalls were the most cost-efficient trap type for sampling reptile species (0.003) and individuals (0.044) per dollar. Between-session recapture rates were greatest in Elliott traps, indicating an increased likelihood of biased capture rates for certain small mammal species over time. Elliott traps were the least efficient traps on most scientific and cost measures, and recorded the greatest overall recapture rates, particularly for Sminthopsis crassicaudata and S. macroura. Body size of one species only, the nationally threatened Pseudomys australis, influenced its capture rate, with larger individuals more likely to be caught in deep pitfalls. Mortality was highest in pitfalls and mostly related to interactions between animals caught in the same trap. Key conclusionsShallow pitfalls are suitable for studies focused on estimating species richness, and reptile diversity and abundance. Deep pitfalls are cost-effective for sampling small mammals. Ethical issues associated with pitfalls could be managed by checking traps more often at night, and/or including materials that provide increased protection from predators caught in the same trap, particularly during periods of high abundance. ImplicationsTrap design profoundly influences cost-effectiveness and welfare outcomes of wildlife research. We provide a tool to assist cost-benefit related decisions.


2007 ◽  
Vol 67 (4) ◽  
pp. 619-625 ◽  
Author(s):  
DR. Scheibler ◽  
AU. Christoff

We inventoried terrestrial small mammals in an agricultural area in southern Brazil by using trapping and prey consumed by Barn Owls (Tyto alba) and White-tailed Kites (Elanus leucurus). Small mammals were trapped in three habitat types: corn fields, uncultivated fields ("capoeiras"), and native forest fragments. A total of 1,975 small mammal specimens were trapped, another 2,062 identified from the diet of Barn Owls, and 2,066 from the diet of White-tailed Kites. Both trapping and prey in the predators' diet yielded 18 small mammal species: three marsupials (Didelphis albiventris, Gracilinanus agilis, and Monodelphis dimidiata) and 15 rodents (Akodon paranaensis, Bruceppatersonius iheringi, Calomys sp., Cavia aperea, Euryzygomatomys spinosus, Holochilus brasiliensis, Mus musculus, Necromys lasiurus, Nectomys squamipes, Oligoryzomys nigripes, Oryzomys angouya, Oxymycterus sp.1, Oxymycterus sp.2, Rattus norvegicus, and Rattus rattus (Linnaeus, 1758)). The greatest richness was found in the uncultivated habitat. We concluded that the three methods studied for inventorying small mammals (prey in the diet of Barn Owls, White-tailed Kites, and trapping) were complementary, since together, rather than separately, they produced a better picture of local richness.


2020 ◽  
Vol 15 (3) ◽  
pp. 663-681
Author(s):  
Robert Owen

Many questions concerning habitat preferences of Neotropical small mammals remain unanswered. These questions include where the animal lives within and among the available habitats, and the temporal (seasonal and interannual) variation in the habitat associations. The objectives of this research were: (1) to determine the associations of non-volant small mammal species (Rodentia and Didelphimorphia) with specific microhabitat characteristics including vegetation structure in an area near the western boundary of the Upper Paraná Atlantic Forest, and (2) to evaluate seasonal and interannual variation in those associations. Three grids were sampled in three seasons (Dry, Wet, Variable) during two years (2015-2017). The four predominant small mammal species (Gracilinanus agilis, Akodon montensis, Hylaeamys megacephalus, and Oligoryzomys nigripes) were evaluated for seasonal and interannual variation in habitat preferences. Each of the four exhibited seasonal and/or interannual variation in microhabitat preferences for three to six of the 17 environmental variables analyzed. This is the first study to explicitly evaluate temporal variation in habitat associations of small mammals in the Atlantic Forest ecoregion. The temporal patterns of habitat association among these four predominant species reveal a complex spatially and temporally dynamic composition and structure in this small mammal community.


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