Diet Of Long-eared Owls Research Articles

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

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

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

Owl diets undergo qualitative changes across the different regions of their area of distribution. During the four winters (from 2014–15 to 2017–18), Long-eared Owls’ pellets were collected at three winterroosts located at the southern part of Pannonian Plain, in the Serbian province of Vojvodina. In 8070 prey items from pellets, we identified 16 mammal and 32 bird species. The Common Vole was the dominant prey species with a proportion in a range from 27.4% to 71.6%. The Muridae family formed a supplementary part of the diet: Mus sp., wood mouse and harvest mouse, during all winters. Birds were also a major supplementary prey during winter 2014–15, comprising 10.6%. A comparison of our results with the diet of Long-eared Owls wintering at the northern Pannonian plain (southwestern Slovakia) indicated an increase the proportion of some species in the southern part. How different land uses in agriculture and environmental conditions may be reflected in the food supply are discussed in relation to the diet composition of Long-eared Owls and an environment whose is richer provides both growing diversity in the diet of these owls and an expansion of their food niche. Our study described the Long-eared Owl as opportunistic predators expanding their food niche in the presence of diversified prey.

Diet of Long-eared Owl and Common Kestrel in an urban landscape (Ukraine)

Abstract In the present study we performed a comparative dietary analysis of two predatory birds, the Long-eared Owl (Asio otus) and the Common Kestrel (Falco tinnunculus) in the district of Lviv city. We found that the Long-eared Owl and the Common Kestrel are typical small mammal specialists within the urban ecosystem. Considering the abundance and biomass of prey, small mammals comprise 98.4% of the Long-eared Owl’s diet. The species composition of mammals coincides almost 50% in the food intake comparison of the two birds. It has been established that the main prey of both species is the Common Vole (Microtus arvalis). The diet of the Common Kestrel is more varied, compared to the Long-eared Owl, due to the consumption of different species of insects (families Gryllotalpidae, Tettigoniidae, Carabidae and Scarabaeidae), reptiles and birds. This result suggested that dietary plasticity of the Common Kestrel facilitate successful adaptation to the urban landscape. The Long-eared Owl is more narrowly specialized in feeding on murine rodents, which reduces the trophic competition between the two predatory birds and allows the coexistence of two predators in the urban ecosystem.

Winter diet and roosting site use of urban roosting Long-eared Owls (Asio otus), and the change in the species’ population size in Southeast Hungary×

Abstract The Long-eared Owl (Asio otus) was chosen as the bird of the year in Hungary by BirdLife Hungary in 2020 to pay more attention to this species. In the present study, we analysed the data collected on the food, changes in the population and the use of the roosting sites of the owls wintering Southeast-Hungary. A total of 4,683 pellets were collected in four winter seasons between 2016 and 2020, of which 5,265 prey animals were identified. We counted the individuals roosting in the winter roosting sites, and from their maximum number we estimated the local population change of the species as well as the success of the breeding. For this, we also used roadkill data from the nearby town, Battonya. The diet of Long-eared Owls in the study area was similar to that observed in other parts of the Carpathian Basin. The smaller differences were mainly due to the different geographical distribution of different prey species. We also identified some species previously having no or very few data, thus we confirmed their stable presence in the area. Different weather factors within the season did not effect owls’ diet. The most varied diet was found in the warmest, least snowy winter. Comparing the feeding data with the data from the 1960s and 1970s, it can be seen that the proportion of preys changed significantly. The proportion of House/Steppe Mice decreased by an order of magnitude, while that of rats increased by the same amount over time. The most likely reasons for this may be changes in agricultural cultivation or local demographic conditions (depopulation). In the 2018/19 season, the proportion of Common Vole in the pellets was much higher than in any other years, suggesting this year’s gradation of the species. The pellets collected in different roosting sites close to each other typically had the same proportions of prey animals. The maximum number of birds observed at the roosting sites did not correlate with the weather of the given season, but was probably related to the effectiveness of the previous breeding season. The population of the species decreased compared to the early 2000’s based on the number of roosting individuals. This may be due to a decline in crow populations. It should be noted, however, that according to both the roadkills in Battonya and the maximum number of the roosting individuals in Kevermes, this drastic decline came to a halt in 2010s.

Small mammals in the diet of long-eared owl (Asio otus) in the southwest of Belarus

The article discusses the species and taxonomic composition of the long-eared owl (Asio otus) preys based on the analysis of pellets (n = 209) collected in the winter-spring period in 2016 in the Malarytsky district (Lozitsa village) and the Brest region district center. The distance between Malaryta town and Lozitsa village is about 10 km. Parts of the skull of 512 small mammals (2.45 individuals per pellet) and one bird were found. Feeding on birds for the long-eared owl is episodic. Representatives of 2 orders, 10 genera and 12 species of small mammals (5 species of shrews and 7 rodents) became preys of the owl. The proportion of rodents is 98.24 % of all preys. The absolute dominant among prey species is Microtus arvalis (85.16 % of all victims), which is consistent with numerous work carried out in other regions. Significant portions are of Apodemus agrarius (4.10 %), Muscardinus avellanarius (2.54 %), Sylvaemus tauricus (1.76 %), and Alexandromys oeconomus (1.56 %). The list of preys is presented by meadow-field, synanthropic and different species actively moving from adjacent forests in the Malaryta river floodplain and canal systems (Sylvaemus tauricus, Sorex araneus, S. minutus, Neomys fodiens). The occurence of two shrew species Crocidura leucodon and C. suaveolens in the city of Malaryta has been proved, which corresponds to similar information for the city of Brest. This suggests that C. suaveolens inhabits the entire territory of the Belarusian Polesie at present. The occurence of the non-abundant species Sicista betulina in vicinities of the town of Malaryta was confirmed. The results obtained confirm the significant trophic effect of the long-eared owl on the local population of the hazel dormouse and also indicate the relatively high abundance of this rodent in the study area. Seven species were identified in pellets of the long-eared owl living near the village of Lozitsa, and 12 species of small mammals were identified in the town of Malaryta. The diversity of the landscape of the town of Malaryta determines the large number of prey species.

Selection of prey by size and sex in the Long-eared Owl Asio otus

ABSTRACTCapsule: Voles predated by Long-eared Owls Asio otus were more likely to be female and smaller than the voles in the available population.Aims: Our study aimed to estimate the size and sex of prey in the diet of Long-eared Owls and compare them with the size and sex of prey in the field.Methods: The study was carried out in 2016 and 2017 at Moscow Region, Russia. Prey remains were extracted from pellets produced by Long-eared Owls. The sex of prey was identifiable due to sexual dimorphism of pelvic bones, and bone dimensions were used to estimate the body mass of prey. Small mammals were also trapped in the study area to compare the sex and size of animals taken as prey with those in the general population.Results: Long-eared Owls did not capture small mammals randomly with respect to size and sex. In general, individuals of the two main prey species in the pellets of Long-eared Owls were significantly smaller than the trapped animals. Long-eared Owls more often caught the females of both species of voles. However, the percentages of females in the diet varied between years.Conclusions: Long-eared Owls more often catch individual voles of a certain size and sex. We suggest that this selective predation could influence not only the number of prey species, but could also impact the structure of their local populations.

Investigation on Diet of Long-Eared Owl (Asio Otus) Inhabiting Fatih Natural Park (Turkey)

Pellet analyses were used to identify small mammal species in the diet of this owl species in order to reveal its ecological role. In this study, 706 pellets of Asio otus were collected from 3 different localities in Fatih Natural Park between February and March 2014. Pellets were dissolved by using 3% NaOH solution and then bones were dehydrated and identified. The aim of this study was to determine mammal composition in the diet of Asio otus inhabiting Fatih Natural Park of Yozgat Province, Turkey. Residues of bone from 1293 individuals/preys corresponding to 42377.41 g biomass in total were detected as the result of analysis. These individuals were identified to belonging to 12 mammal species ( Crocidura suaveolens , Suncus etruscus , Microtus hartingi/lydius , Microtus levis , Microtus sp., Cricetulus migratorius , Mesocricetus brandti , Apodemus sp., Apodemus sylvaticus , Apodemus whitherbyi , Mus macedonicus , and Meriones tristrami ) from 3 families and 8 genera. Microtus hartingi/lydius, which is known as agricultural pest, was dominant in the diet of Asio otus . When diversity of mammal species within the food composition was examined, Asio otus nesting in forest was found to primarily prefer agricultural and steppe areas, and was also found in woody and bushy areas. The use of Asio otus can be taken into consideration when dealing with rodent species known as agricultural pests.

Weather conditions explain variation in the diet of Long-eared Owl at winter roost in central part of European Russia

The influence of weather conditions on the winter diet of the Long-eared Owl was studied in 2005-2013 at one roost site in Moscow, Russia. Pellets were collected every week from November to March. The diet composition of the owls included 6 rodent species, 2 in-sectivore species and 18 bird species. Common Vole was by far the most frequent prey (70.0%), followed by Ural Field Mouse (10.8%) and Brown Rat (7.5%). Among birdprey (5.3%), House Sparrow, Great Tit, Bullfinch, Tree Sparrow and Blue Tit were the most numerous species. The winter diet showed marked interannual fluctuations. In terms of weather conditions, depth of snow cover appears to be the most important factor affecting the availability of the most frequent prey species and prey groups in the diet of the Long-eared Owl. Wind speed and precipitation do not play a significant role in predating on voles and mice. The proportion of bird prey was relatively low, but increased with precipitation, indicating the high importance of birds as an alternative prey for owls. The results thus suggest that specific features of behavior and activity of prey in different weather conditions explain their proportions in the diet of the Long-eared Owl.

Diet and breeding success of long-eared owls in a semi-arid environment

Only a few studies, and mostly in temperate climates in Europe, have examined the breeding and diet of long-eared owls (Asio otus) compared to studies of cavity-breeding owls, possibly because of the difficulties in reaching the nests of the former. Here we studied a population of long-eared owls, monitoring the diet of breeding owls and that of owls at a communal roost, every two to three months during 2006–2009, in a semi-arid region in Israel. It was found that the studied owls produced more young than in most countries in Europe. Diet was not associated with breeding parameters of the owls, whereas laying date was negatively correlated with both clutch size and number of nestlings. We found that more social voles (Microtus socialis) and fewer birds and house mice (Mus musculus) made up the diet at nests than that of adults at the roosts. The diet and breeding of long-eared owls in Israel differ from that in Europe, with birds and mice comprising an important part of the diet, in addition to voles.

Feeding specialization of urban Long-eared Owls, Asio otus (Linnaeus, 1758), in Jerusalem, Israel

The diet of Long-eared Owls (Asio otus) that breed and hunt within the grounds of a bird-ringing station located in a large city park in Jerusalem, Israel, was investigated. 13 species of bird were the most common prey group (91% by number) with a frequency of occurrence of 99% in pellets, with House Sparrows, Passer domesticus, and Blackcaps, Sylvia atricapilla, as the most frequent prey species (22% and 17% by number). 29% of the bird specimens found in pellets had been ringed at the ringing station. The frequency of residential and migratory passerines caught by Long-eared Owls and ringed at the ringing station was similar, whereas more migrants were captured and ringed during the spring than summer. A comparison of bird species that were hunted relative to their frequency in the habitat revealed that the owls caught more Sylvia warblers than expected. Long-eared Owls in this study most probably specialised on birds because of the abundance of passerines and the lack of small mammals.

Comparison of the Diet of Two Desert-living Owls, the Long-eared Owl(Asio otus) and Little Owl (Athene noctua) from Southern Mongolia

The diet of two sympatric owl species, the long-eared owl (Asio otus) and the little owl (athene noctua) was investigated in an arid area of southern Mongolia using pellet analysis. In total 334 pellets of long-eared owl and 52 pellets of little owl were analysed, revealing the presence of five small mammal species (Dipodidae, three Muridae and one Soricidae), small birds and invertebrate fragments. Accumulative composition plots indicated a batch size of 35-60 pellets was sufficient to reveal representative diet composition. Small mammals comprised the largest component of the diet of long eared owls with four species recorded, Phodopus was the most frequently occurring (85%) followed by Meriones (33%). Bird and invertebrate remains were also found in long-eared owl pellets but comprised less than 2%. In contrast, invertebrates were the highest occurring component of the diet of little owls (35%), with small mammals occurring in only 40% of pellets. Meriones was the most frequently recorded small mammal in owl pellets (23%) and contributed the greatest in terms of overall rodent biomass. There was a highly statistically significant difference in the diet of the two species (÷2 = 2043, d.f. = 4,P<0.001). Levin's measure of niche breadth was greater for little owls (0.71) than long-eared owls (0.51), but overall the two species had low niche overlap using Levin's index (0.22). These results are discussed in relation to previous findings of these two species.

Numerical and Functional Responses of Kestrels, Short‐Eared Owls, and Long‐Eared Owls to Vole Densities

We studied numerical and functional responses of breeding European Kestrels (EK) (Falco tinnunculus), Short—eared Owls (SO) (Asio flammeus), and Long—eared Owls (LO) (Asio otus) during 1977—1987 in 47 km2 of farmland in western Finland. The pooled mean yearly breeding density varied from 0.1 to 2.4 pairs/km2. The number of nesting EKs (range 2—46 pairs), SOs (0—49), and LOs (0—19) fluctuated in close accordance with the spring density of Microtus (M. agrestis and M. epiroticus) voles. The mean yearly number of fledglings produced per pair ranged from 0.4 to 3.8 and, for each species, was positively correlated with spring density of Microtus voles. Due to their high degree of mobility, EKs, SOs, and LOs were able to track the population fluctuations of their microtine prey without time lags. An increase in microtine densities caused a rapid immigration into the study area and a decrease caused a rapid emigration from the area. Microtus voles were the most important prey group by mass in the diet of each species. Water voles, bank voles, shrews, and small birds were the most frequent alternate prey. The spring density of Microtus spp. was positively correlated with the percentage of these voles in the diet of EK, SO, and LO. The pooled functional response curve of these three raptor species to the fluctuating densities of Microtus spp. was close to linear, indicating that consumption rates are independent of vole densities. Breeding EKs, SOs, and LOs seemed to take a larger proportion of voles available in peak years than in low ones.

Nesting and Diet of Long-Eared Owls in Conifer Forests, Oregon

Long-eared Owls (Asio otus) nested in extensive stands of grand fir (Abies grandis) in northeastern Oregon. Nineteen of 20 nests were in dwarf-mistletoe brooms (Arceuthobium spp.) in Douglas-fir (Pseudotsuga menziesii) trees. Young were raised at 70% of the nests, and brood size averaged 3.0. The northern pocket gopher (Thomomys talpoides) was the primary prey item both in frequency (56%) and biomass (74%). These observations differ from those reported previously for the Long-eared Owl in North America.