Long-eared Owl Asio Otus Research Articles

Trophic diet of the Long-eared owl Asio otus (Linnaeus, 1758) (Aves, Strigidae) in the Daya d'El-Gouffa (Laghouat, Algeria)

This research aims to study the trophic diet ofthe long-eared owl Asiootus and based on the examination of 120 regurgitation pellets of this raptor. These pellets were collected during the period from August to november 2020, near the Dayad'El-Gouffa located in the region of Laghouat. The analysis of the 120 pellets revealed a total of 273 individuals divided into 39 species belonging to four zoological classes. The consumption of small mammals, mainly Rodentia-Gerbillidae, is very common in arid environments. These constitute the basis of the diet of this raptor. Of the four families of rodents consumed, the Gerbillidae family is the most dominant one. It clearly stands out from the other families with a very high rate of 92.5% of the total rodents consumed. The Dipodidae are the least consumed (4.8%). In terms of species, Pachyuromusduprasi is the most dominant species with 31.5%. The values of the Shannon-Weaver index seem to be high. The highest one is recorded in november with 4.2 bits against 3.1 bits recorded in august. The calculated equitability values tend towards one for all four months of the study, so the numbers of the different components of the long-eared owl diet tend to be in balance with one another. This implies that Asiootus behaves as a generalist opportunistic predator.

Small mammals near Janowiec nad Wisłą (middle-eastern Poland) on the basis of prey composition of the tawny owl Strix aluco and long-eared owl Asio otus

At two sites near Janowiec nad Wisłą (middle-eastern Poland) the species composition of a small mammal community in the diet of the tawny owl Strix aluco and long-eared owl Asio otus has been examined. The bones of 128 mammals have been extracted from S. aluco pellets gathered in the years 2014-2015, whereas 401 mammals have been extracted from A. otus pellets collected in the years 2023-2024. Dominant species in the diet of S. aluco (the site bordering woodland) were Clethrionomys glareolus (31.3%), Apodemus agrarius (16.4%) and Apodemus flavicollis (12.5%), while in the case of A. otus (the site bordering open landscape) Microtus arvalis (55.1%) appeared most frequent. Altogether 16 species were recorded representing: Soricomorpha (4), Chiroptera (1), Rodentia (10) and Carnivora (1). Two bats caught as prey belonged to the species of Myotis nattereri, common in this part of Poland. Most interesting species were Crocidura leucodon, whose recorded sites are near its range limit, and Muscardinus avellanarius – the species infrequently recorded in central and eastern Poland.

Birds of Kanetiya area - inventory, notable sightings, and overview of seasonal changes in reporting frequency of bird species in an unprotected area of Himachal Pradesh, India

Biodiversity of unprotected areas in the western Himalayan region is under threat. Despite this, it is poorly studied and documented. The citizen science platform eBird was used to record bird species of the unprotected Kanetiya area (Darbhog panchayat), Shimla, Himachal Pradesh from August 2019–2020. Reporting frequency using this data was calculated to represent an index of species abundance. This was calculated independently for each species across three seasons and reported as a metric that can be tracked over time. One-hundred-and-twenty-four (20% of the species from Himachal Pradesh) species of birds belonging to 13 orders and 43 families were recorded. Of these, 37 (30%) were recorded year-round and the remaining 87% (80%) were migratory. The checklist consisted of five species of high conservation concern and 22 species of moderate conservation concern. This checklist also provides insights into the distributions of some species whose ranges within India are not yet well defined (Northern Long-eared Owl Asio otus, Aberrant Bush Warbler Horornis flavolivaceus, Himalayan Owl Strix nivicolum) and into migration through this part of the Himalaya (Black Stork Ciconia nigra). Locals can be educated to upload short checklists for monitoring since they have helped the local forest department’s conservation efforts.

A Survey of Sex Ratios of Raptors at a Rescue Center in China

ABSTRACT The sex ratio is an important concept in estimating population demography, and such data could contribute to both theoretical research and conservation. Although numerous studies have analyzed the sex ratios of raptors in the wild, few studies have focused on the sex ratios of raptors in wildlife rehabilitation facilities. Here, we report the results of polymerase chain reaction (PCR)-based sex identification of raptors brought to the Beijing Raptor Rescue Center in 2018–2020. This rescue center is located in eastern China, on a major migratory route for raptors in East Asia. We identified the sex of 646 individuals (belonging to 29 species) using two sets of primers, and analyzed the sex ratios of five species with a sample size >30 individuals. Generally, the sex ratios differed among species: the sex ratio of Eurasian Kestrels (Falco tinnunculus) was skewed toward males (P = 0.006), while the sex ratio of Eurasian Sparrowhawks (Accipiter nisus) was skewed toward females (P = 0.024). The sex ratio of Long-eared Owls (Asio otus) tended to be female-biased (P = 0.058). There was no significant bias of sex ratio in Oriental Scops-Owls (Otus sunia) or Amur Falcons (Falco amurensis). We discussed several possible reasons that could drive the biased sex ratios of raptors brought into rehabilitation centers. Our findings could be helpful for future studies on sex identification of raptors and conservation efforts.

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)

Short communication: Vocalization of the Long-eared owl Asio otus (Strigiformes, Strigidae) in the Middle Volga, Russia

Abstract. Andreychev A, Lapshin A, Kuznetsov V. 2021. Short Communication: Vocalization of the Long-eared owl Asio otus (Strigiformes, Strigidae) in the Middle Volga, Russia. Biodiversitas 22: 5325-5330. Both daily and seasonal year-round vocalizations of the Long-eared owl (Asio otus) (Linnaeus, 1758) were recorded in the Middle Volga River region, Russia with the use of digital dictophones. Voice recorders were installed in the daytime for up to 5 days. The maximum duration of continuous operation of voice recorders was about 140 hours. By the time the previous recording was finished, we would arrive and move the recorder to a different location. The Long-eared owl can be classified as a moderately vocalizing bird, with calls recorded during 3 spring months. Peak activity is associated with pre-incubation and incubation periods. In the spring months, calls of the Long-eared owl were recorded from 16.37 h to 03.43 h. In the spring, the Long-eared owl began to cry before sunset (from 1 hour 30 minutes to 3 hours 15 minutes) and after sunset (from 56 minutes to 3 hours 39 minutes). Vocalization started after sunset for an average of 50 minutes. Vocalization always ended before dawn (to 1 h 21 min). Statistically significant differences in the duration of vespers and morning vocalizations were obtained with the use Mann-Whitney U test (Z = -3.08; p < 0.05).

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.

Field evaluation for playback surveys: species-specific detection probabilities and distance estimation errors in a nocturnal bird community

ABSTRACT Capsule During playback experiments, the distance from the surveyor to the call influences the chances of detection across nocturnal species in farmland and woodland habitats. Aim To evaluate how distance affects surveyor detection capability, expressed as the probability of hearing broadcast calls and of estimating their distances correctly, in a nocturnal bird community. Methods We conducted a playback field experiment in farmland and woodland areas within an agricultural landscape in winter and summer 2020. Vocalizations of five species (Little Owl Athene noctua, Tawny Owl Strix aluco, Long-eared Owl Asio otus, Common Nightingale Luscinia megarhynchos, Water Rail Rallus aquaticus) were broadcast at various distances to a surveyor, who attempted to detect them and, if successful, to classify them into predefined distance zones. Binomial GLMMs were used to estimate detection probability as a function of distance, and the effects of habitat and season on this relationship. Results The distance of the broadcast call from the surveyor had a significant effect on detection probability in both habitats. In woodland, the probability of hearing calls was significantly higher in winter, while estimating distances correctly was generally higher in summer. An increase in field experience improved our detection capability, mainly in terms of distance estimation, for which errors were mostly overestimates. Conclusions The probability of hearing calls and distance estimation accuracy varied between species. Most Little and Tawny Owl calls were detected within a 200 m radius of the surveyor, while this was 100 m for the other species. For a multi-species community-level study, playback surveys are thus likely to be most representative of a 200 m radius surrounding the surveyor where the probability of detection is highest, while estimates of distance from the observer are likely to be inaccurate in most cases. Field evaluations such as this should be implemented prior to actual playback surveys.

Long-eared Owl Asio otus breeding in a Caspian Gull Larus cachinnans colony: Reversed roles in protective nesting association?

We describe the event of Long-eared Owls Asio otus nesting on an island within a colony of Caspian Gulls Larus cachinnans at the Mietków Reservoir (SW Poland). The owls nested in an old (possible corvid) nest in a willow and raised two owlets. They probably did not hunt gulls, neither adults nor chicks. We suggest that, in this case, the Long-eared Owls benefitted from breeding within a gull colony because of the added security against predators that the gulls provided.

Winter Diets of Long-Eared Owl (Asio otus) in Thrace, Turkey

Long-eared owls (Asio otus) are common avian predators in Turkey. Their diet consists primarily of small mammals, but they also feed on bats, birds, amphibians, reptiles, insects, and fish. Limited research has been conducted on long-eared owl diets and pellet characteristics in Turkey, yet this knowledge would improve our understanding of their ecological role in the environment. We investigated prey items in pellets at winter sites of Asio otus in Edirne, Kirklareli, Tekirdag, and Istanbul. We collected 2143 pellets from winter sites and counted 3458 prey items. We identified 30 taxa including 16 mammals, 12 birds and 2 insects. Asio otus primarily consumed small mammal species (97.9%) which consisted mainly of rodents (89.6%, including Cricetidae 45.95%, Muridae 43.7%), Eulipotyphla (1.2%), and unidentified mammals (7.1%). A small proportion of birds (1.9%) and insects (0.2%) also were consumed. Asio otus inhabited small coniferous woodlands at edge of farmlands during winter, but their diet varied with location. Muridae were primarily consumed in Istanbul and Tekirdag, whereas Cricetidae were mostly consumed in Kirklareli and Edirne. Our study shows that Asio otus feeding habits shift depending on prey abundance and that they are not specialists for Microtus species only.

Molecular characterization of the re-emerging West Nile virus in avian species and equids in Israel, 2018, and pathological description of the disease

BackgroundIn this report we describe the molecular and pathological characteristics of West Nile virus (WNV) infection that occurred during the summer and fall of 2018 in avian species and equines. WNV is reported in Israel since the 1950s, with occasional outbreaks leading to significant morbidity and mortality in birds, high infection in horses and humans, and sporadic fatalities in humans.MethodsAnimal and avian carcasses in a suitable condition were examined by post-mortem analysis. Tissue samples were examined for WNV by RT-qPCR and the viral load was quantified. Samples with sufficient material quality were further analyzed by Endpoint PCR and sequencing, which was used for phylogenetic analysis. Tissue samples from positive animals were used for culturing the virus in Vero and C6/36 cells.ResultsWNV RNA was detected in one yellow-legged gull (Larus michahellis), two long-eared owls (Asio otus), two domesticated geese (Anser anser), one pheasant (Phasianus colchicus), four hooded crows (Corvus cornix), three horses and one donkey. Pathological and histopathological findings were characteristic of viral infection. Molecular analysis and viral load quantification showed varying degrees of infection, ranging between 70–1.4 × 106 target copies per sample. Phylogenetic analysis of a 906-bp genomic segment showed that all samples belonged to Lineage 1 clade 1a, with the following partition: five samples from 2018 and one sample detected in 2016 were of Cluster 2 Eastern European, two of Cluster 2 Mediterranean and four of Cluster 4. Four of the positive samples was successfully propagated in C6/36 and Vero cell lines for further work.ConclusionsWNV is constantly circulating in wild and domesticated birds and animals in Israel, necessitating constant surveillance in birds and equines. At least three WNV strains were circulating in the suspected birds and animals examined. Quantitative analysis showed that the viral load varies significantly between different organs and tissues of the infected animals.

Colonial wintering of Long-eared owl (Asio otus) in Botoșani County (N-E Romania)

Colonial wintering of Long-eared owl (Asio otus) in Botoșani County (N-E Romania)

Comparative analysis of long-eared owl (Asio otus) winter diet from two european cities – Chisinau (Republic of Moldova) and Bacau (Romania)

Comparative analysis of long-eared owl (Asio otus) winter diet from two european cities – Chisinau (Republic of Moldova) and Bacau (Romania)

Comparing Trophic Niches of Sympatric Raptors in Agricultural Landscape in Central Poland

According to basic ecological principle, species that share the same niche do not occupy the same environment for a long time, and sympatry of two or more such species provides an interesting field for the analysis of their trophic niche differentiation. To examine the potential differences in the dimensions of the trophic niche we studied the diet of three sympatric avian predators that prey on colonial Microtus rodents. The study area in central Poland is located in an agricultural landscape, composed of crop fields, as well as meadows and pastures located within a small river valley. The pellets of long-eared owl (Asio otus), barn owl (Tyto alba) and kestrel (Falco tinnunculus) were collected from the 750 m2 study site including church building and its surrounding in the spring of 2016 and 2017. The analysis of pellets provided data on a total of 4128 vertebrate prey individuals (1914 from barn owl, 1749 from long-eared owl, and 465 from kestrel). The most important prey group of all three predators were small mammals (90%, 14 species) and the most frequently preyed species was Microtus arvalis (making up 72% of vertebrate prey of long-eared owl, 59% of kestrel and 53% of barn owl). Despite the general similarity in the diet composition, there were differences in the contribution of several prey species (e.g. Soricomorpha, M. arvalis, Mus musculus, Rattus norvegicus, and Apodemus spp.) and the diversity of the diet between the predators. We conclude that the trophic niches of the studied sympatric species differ in several dimensions, including diel activity, prey size and taxon-specific feeding preferences.

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.

Feeding Ecology and Prey Selection by Wintering Long-Eared Owls Asio otus in Mediterranean Agrosystems

The diet composition and dietary patterns of the Long-eared Owl Asiootus were studied in Mediterranean agrosystems in central Crete (Greece) over the winters of 2009–2015. Overall, 2,819 prey items were recovered from 1,207 pellets, belonging to six taxa of mammals, 22 taxa of birds and four taxa of insects. Small mammals were the most common prey species, accounting for 75.8% by frequency and 79.7% by biomass, followed by birds (23.2% and 20.1%); the latter being rather an island component compared to continental regions. The House Mouse Mus musculus was the most important prey species in the owl's diet (56.3%) ahead of the Wood Mouse apodemus sylvaticus (9.51%) and the Black Rat Rattus rattus (7.9%). The species proved to be a significant rodent predator in olive groves and vineyards during winter months, selecting Wood Mouse and young Black Rat more than expected. Long-eared Owl feeding ecology studies could lead to improved land management and agricultural practices in the rural landscapes of the Mediterranean.

Winter Roost Tree Selection and Phenology of the Long-Eared Owl (Asio otus) in Crimea

The winter roost of the long-eared owl Asio otus in Crimea (South of Ukraine), located in Simferopol, is described. In 2015–2017, the number of long-eared owls varied on a convex curve, with the maximum reached at the end of November and in December. The birds exhibited a strong preference for roosting in conifers, where we recorded 89% of the owls. There was an inverse relationship between the mean of the maximum daily temperature (°C) and the number of owls in both seasons. The owls were not sensitive to abrupt but short-term temperature changes, but the temperature decrease curve caused practically synchronous changes in the dynamics of bird numbers. It was found that the number of owls significantly differed based on weather conditions in 16 trees. The proportion of owls sitting on coniferous trees increased with unfavourable weather, and the converse pattern was observed for deciduous trees.

Complete mitochondrial genome of the Northern Long-eared Owl (Asio otus Linnaeus, 1758) determined using next-generation sequencing

In this study, the mitogenome of Asio otus, the Northern Long-eared Owl, was analysed using Illumina next-generation sequencing. The mitogenome was found to be a circular molecule, 17,735 bp long with a slight AT bias (53.0%). The gene arrangement pattern was the same as that of a typical vertebrate, containing 37 genes (13 protein-coding genes (PCGs), 22 transfer RNA genes, two ribosomal RNA genes, and a non-coding control region). In the putative control region (1984 bp), there were two types of tandem repeats at the end of the region. A phylogenetic tree was constructed using the 13 PCG sequences discovered in this study and those of that have been previously published of other Strigidae species and revealed a close relationship between A. otus and A. flammeus. The newly generated mitogenome from this study enriches the genomic resources available for future evolutionary studies and promotes conservation genetics of this species.

Fish in the diet of the Long-eared Owl Asio otus

ABSTRACTCapsule: Analysis of regurgitated pellets showed that fish were a very rare prey in the diet of the Long-eared Owl Asio otus. Remains of 38 individual fish were found at 8 of 121 nests and only in 2 out of 11 years. Occurrence tended to be more frequent in warm dry periods, when water ditches were dry.

Morphology of the esophageal mucosa in long-eared owl and eurasian jay

The morphology of the esophageal mucosa in long-eared owl (Asio otus) and Eurasian jay (Garrulus glandarius) has been studied. Samples with exception of the region of the esophageal tonsil were obtained from 3 adult birds of each species. They were studied by light microscopy using classical methods of morphological research. The tissue samples were fixed in 10% neutral buffered formalin and embedded in paraffin block and finally the section were cut at 5–10 µm thickness using sliding microtome and stained with hematoxylin and eosin, according to Van Gizon and Weigert and impregnated with silver nitrate according to Kelemen. The esophageal mucosa consisted of four layers: epithelium, lamina propria, muscularis mucosae, and submucosa. The epithelium was stratified squamous and better developed in the cranial part of the esophagus. The lamina propria was represented by a loose connective tissue with small amount of elastic fibers. In the long-eared owl tightly located numerous small secretory sections of the esophagus glands organised in 1–3, and in branches of large folds up to 6 layers, were found. Their short excretory ducts opened to the surface of the mucosa. The muscularis mucosae was represented by a smooth muscle tissue with bundles of cells directed longitudinally and in some areas appeared to be absent. The submucosa was well developed, and as well as lamina propria was formed by a loose connective tissue with a large number of elastic fibers. In the submucosa of the Eurasian jay secretory departments of large, not tightly located, esophageal mucous glands were found. The esophageal mucosa of this birds formed well-developed folds, which were composed of all its layers. Their number in the long-eared owl was 20–25 and in the Eurasian jay – 5–9. The shape of folds on the transverse section is not the same: in the long-eared owl it was finger-shaped and leaf-shaped, but in the Eurasian jay it was wedge-shaped. Some large folds in the long-eared owl branched into the secondary mucosal folds. The height of folds in cranial part of the esophagus was larger than in caudal part. In both parts of the esophagus of long-eared owl the height of the large and middle folds was larger than that in the Eurasian jay. The height of small folds in the Eurasian jay was greater than that in the long-eared owl. In both parts of the esophagus of this birds, the fold’s width at the base exceeded its width at the top. In the Eurasian jay the width of base and top of large, medium and small folds was larger than that in the long-eared owl. The esophageal mucosa was poor on immune formations. They were represented by single accumulations of diffuse lymphoid tissue, and in the Eurasian jay – even by secondary lymphoid nodules.