Short-eared Owl Asio Flammeus Research Articles

Use of dwarf shrubland–grassland mosaics by a nomadic predatory bird: the Short-eared Owl Asio flammeus

Use of dwarf shrubland–grassland mosaics by a nomadic predatory bird: the Short-eared Owl Asio flammeus

The avifauna of Biak Island, Papua, Indonesia with comments on status, conservation, natural history and taxonomy

New Guinea and its satellite islands are justly renowned for their spectacular and highly diverse, endemic avifauna. The oceanic island of Biak and its satellites, in Teluk Cenderawasih (formerly Geelvink Bay), Papua province, Indonesia, has an avifauna of c.159 species including the largest number of endemics of any island in the New Guinea region: seven species are strictly endemic to Biak and another six are shared with other Teluk Cenderawasih islands but not Yapen. Despite Biak attaining an elevation of c.1,034 m there are no species whose range on Biak is known to be entirely montane. We provide a physical description of Biak and its twin Supiori, and discuss the biogeography and conservation of their birds. We present a detailed checklist of all species recorded to date. Since the publication in 1939 of Mayr & Meyer de Schauensee, 66 species have been added to the Biak list, of which Short-eared Owl Asio flammeus and Black-winged Stilt Himantopus himantopus are new for the entire Australo-Papuan region and Grey Heron Ardea cinerea only the second for the region and first for New Guinea; 47 of these additions are also first records for any island in Teluk Cenderawasih. An appendix summarises the distribution and status of birds in Teluk Cenderawasih (excluding mainland New Guinea species only on Yapen).

Adaptive Features of the Eye to the Ecological Habit of the Short-Eared Owl Asio flammeus and Japanese Scops Owl Otus semitorques

In this study we investigated the eye morphology and retinal topography of two owl species in relation to their visual environment. Although Short-eared Owl Asio flammeus is larger and weighs more than Japanese Scops Owl Otus semitorques, its eye dimensions (weight, corneal diameter, and axial length) are all smaller than the scops owl's. Owl retinas were examined in Nissl-stained whole-mount preparations. The total number of retinal ganglion cells (RGCs) was greater in the Japanese Scops Owl (4,703.0×103 cells) than in the Short-eared Owl (2,346.8×103 cells). The eye morphology of, and the number of RGCs in the Japanese Scops Owl indicate that it is more adapted to a nocturnal habit. An area of high-density RGCs was horizontally distributed in the temporal retina of the Short-eared Owl, with a peak density of 17.4×103 cells/mm2. In the Japanese Scops Owl's temporal retina, there was an oval-shaped arrangement with a peak density of 23.1×103 cells/mm2. These distributions indicate that whereas Short-eared Owl is adapted to open habitats, Japanese Scops Owl is adapted to enclosed habitats. The RGCs of both species were classified into three categories (small, medium, and large) based on the size and appearance of somas. In both species, medium-sized cells predominated, and the proportion of large-sized cells was smallest. The distribution and high-density areas differed among these groups, suggesting adaptation to the visual environment. The high-density areas of these groups cover the nasal visual fields, which include the overlap for binocular vision.

First Photographic Evidence of Short-eared Owl Asio flammeus (Pontoppidan, 1763) from Sarlahi district, Nepal

This paper presents the first photographic record of the Short-eared Owl Asio flammeus, one of the least studied species of Nepal during opportunistic survey. The new record for Bagmati River stretch on 26 November 2020 were five pairs of Asio flammeus in a grassland dominated area adjacent to agricultural land in Sarlahi district. With this record, conservation efforts in the area should include the regular monitoring and controlled human activities. Moreover, it is crucial to develop conservation awareness on the importance of owls in the ecosystem. It is also necessary to change the perception and attitude of people towards owl which are perceived as sign of evil.

Diet of sympatric Barn Owls Tyto alba and Short-eared Owls Asio flammeus in an agricultural landscape in south-east Spain

The diets of the Barn Owl Tyto alba and the Short-eared Owl Asio flammeus have been extensively studied worldwide over the past few years, especially on the Iberian Peninsula. Nevertheless, very few studies have examined the diets and the trophic niche overlap in areas where these two raptor species occur in sympatry. As such, in this study we compared the diets of the Barn Owl and the Short-eared Owl inhabiting agricultural landscapes of the Vega de Granada, south-east Spain, based on pellet analysis. The diets were very similar, as both owls preyed mainly on small mammals, the Algerian Mouse Mus spretus being the prey most commonly found in pellets from both species. Although the diet of the Barn Owl was more diverse than that of the Short-eared Owl, the food niche overlap was very high, thus indicating a low interspecific trophic segregation. Despite the similarities between both diets, the frequency of the Mediterranean Pine Vole Microtus duodecimcostatus was much higher in pellets from the Barn Owl, thus suggesting that the Barn Owl may exert pest control in years when the Mediterranean Pine Vole occurs in high numbers.

Helminth fauna of birds of prey (Strigiformes: Strigidae, Tytonidae) in the Non-Black Earth Region of the Russian Federation

The purpose of the research is studying helminths of carnivorous birds of the order of owls (Strigiformes) found in the Non-Black Earth Region of the Russian Federation.Materials and methods. From 2015 to 2020, complete helminthological dissections were carried out by the Skryabin method for 72 birds of the order of owls after their spontaneous death: 8 specimens of the short-eared owl Asio flammeus, 6 specimens of the Ural owl Strix uralensis, 4 specimens of the little owl Athene noctua, 9 specimens of the barn owl Tyto alba, 19 specimens of the tawny owl S. aluco, and 26 specimens of the long-eared owl A. otus. The study material was provided by rehabilitation centers and veterinary clinics in Moscow City and the Moscow, Tula and Kaluga regions. The helminths were fixed according to generally accepted methods; the species was identified taking into account specific morphological characters.Results and discussion. Total infection rate in owls was 89.9%. All studied birds were found to have mixed infections with two or more types of helminths. We identified 15 helminth species including 3 species of trematodes (Neodiplostomum attenuatum, Strigea falconis, S. strigis), 2 species of cestodes (Cladotaenia globifera, Paruterina candelabraria), 9 species of nematodes (Syngamus trachea, Cyrnea leptoptera, Microtetrameres inermis, Synhimantus laticeps, Porrocaecum depressum, P. spirale, Capillaria tenuissima, Baruscapillaria falconis, and Capillaria sp.) and 1 acanthocephalian species (Centrorhynchus aluconis). For the first time, new hosts were identified for the following helminth species: the barn owl, short-eared owl and little owl for the trematode N. attenuatum, the Ural owl and little owl for S. falconis, the long-eared owl for the nematode S. trachea, the short-eared owl and tawny owl for C. leptoptera, and the tawny owl for M. inermis.

Short-eared Owl (Asio flammeus)’s winter diets in northwestern Turkey (Thrace)

Short-eared Owl (Asio flammeus)’s winter diets in northwestern Turkey (Thrace)

Expert knowledge assessment of threats and conservation strategies for breeding Hen Harrier and Short-eared Owl across Europe

SummaryHen Harrier Circus cyaneus and Short-eared Owl Asio flammeus are open-country birds of prey with overlapping distributions. Although both species face similar conservation threats across their ranges, work to date has largely been undertaken at a national scale with few attempts to collate and assess factors relevant to their conservation at an international scale. Here we use an expert knowledge approach to evaluate the impact of conservation threats and the effectiveness of conservation strategies for each species across Europe. We report results of responses to a questionnaire from 23 Hen Harrier experts from nine countries and 12 Short-eared Owl experts from six countries. The majority of responses for both species reported declines in breeding numbers. The perceived impact of threats was broadly similar for both species: ecological factors (predation, extreme weather and prey availability), changes in land use (habitat loss and agricultural intensification) and indirect persecution (accidental nest destruction) were considered to be the greatest threats to breeding Hen Harrier and Short-eared Owl. Short-eared Owl experts also highlighted lack of knowledge and difficulties associated with monitoring as a major conservation challenge. Despite broad-scale similarities, geographical variation was also apparent in the perceived importance of conservation threats, with some threats (such as direct persecution, large-scale afforestation or habitat degradation) requiring country-specific actions. Implementation of different conservation strategies also varied between countries, with the designation of protected areas reported as the most widespread conservation strategy adopted, followed by species and habitat management. However, protected areas (including species-specific protected areas) were perceived to be less effective than active management of species and habitats. These findings highlight the overlap between the conservation requirements of these two species, and the need for collaborative international research and conservation approaches that prioritise pro-active conservation strategies subject to continued assessment and with specific conservation goals.

A winter roost count of the Short-eared Owl Asio flammeus (Aves: Strigiformes: Strigidae) at Porbandar, Gujarat, India

The Short-eared Owl Asio flammeus is a common to uncommon winter visitor to Gujarat. The species roosted in bushes of Prosopis juliflora in the grassland of Shiroda area, Odadar Village of Porbandar District. Communal roosts were identified by foot surveys between 9–17 November 2016. A total of 20 individuals co-existed with grazing cattle in the grassland of ca. 1km2. At present due to their restricted nesting habits and nomadic nature, the species is vulnerable to habitat loss at their feeding and roosting grounds. Conversion of open habitats to agriculture, grazing, recreation, housing and tourism development are the current threats to the species in the wetland complex. The IUCN conservation status further confirms that though they are assessed as Least Concern, in spite of the species population constantly declining with global population estimated at 3,000,000 individuals which equates to 2,000,000 mature individuals. The present study is the first systematic attempt to count a roost in Gujarat.

Diets of native and introduced apex predators in Hawai'i

We report here on the diets of four apex predators in Hawai‘i: the native pueo or Hawaiian short-eared owl (Asio flammeus sandwichensis) and three introduced species, the barn owl (Tyto alba pratincola), the feral cat (Felis catus) and the small Indian mongoose (Herpestes javanicus). To better understand dietary relationships between these predators, we studied diet, focusing on areas where they occur together. We collected disgorged owl pellets, and cat and mongoose faecal scats from eight areas located on five of the main Hawaiian Islands and identified prey items to the lowest possible taxonomic level. All species consumed rodents, birds, and arthropods, and the mammal species also included plants in their diets. The two owl species and the cat preyed primarily on rodents, whereas small cockroaches predominated in the diet of the mongoose. Diets of the owl species and the cat, but not the mongoose, varied significantly between areas. Dietary overlap was highest between the pueo and the barn owl and lowest between the owl species and the mongoose. Although barn owls took more rats than pueo, there was no evidence that the two owl species partitioned house mouse prey by size. On islands where there are no mongoose, both owls took a greater proportion of large arthropods in their diet, suggesting that mongoose reduced the abundance of the arthropod species that owls commonly took. There was no significant difference in pueo diets before and after introduction of the barn owl.

Wintering ecology and nomadic movement patterns of Short-eared Owls Asio flammeus on a subtropical island

ABSTRACTCapsule: Short-eared Owls Asio flammeus showed a female-biased sex ratio in their southernmost wintering grounds in Oriental Asia. This is the first description of a nomadic movement pattern in this area.Aims: To investigate the sex ratio, movement patterns, home range size and habitat preference of non-breeding Short-eared Owls in subtropical Taiwan.Methods: Eleven Short-eared Owls were radio tracked following trapping and transportation away from an airport as part of the management of bird-strike risk for aeroplanes.Results: Our results indicated a female-skewed (75%) sex ratio for Short-eared Owls wintering in Taiwan. The owls demonstrated a nomadic behaviour by showing a repetitive pattern of high roosting site fidelity in the short term, followed by a long-distance movement to a different discrete area. Grasslands were commonly used as day-roosting sites but agricultural habitats were favoured at night.Conclusion: Compared to on the breeding ground, the wintering owls exhibited a much larger home range size and exploit more dispersed patches of suitable habitats. These results revealed a notable conservation issue for the wintering owls, especially in the degraded and partially developed landscapes in subtropical countries.

Overview of occurrence of the Short-eared Owl Asio flammeus between 1995 and 2015 in Slovenia and its probable breeding in irruptive year 2008

Abstract Between 1995 and 2015 the number of records of Short-eared Owl Asio flammeus in Slovenia increased drastically, especially after 2007, but the species occurred regularly every year since 2002. Before that, the Short-eared Owl was regarded as a very rare migrant in Slovenia. Most of the observations were from wintering and migration periods, and the most important areas for the species in Slovenia were Ljubljansko barje, Lake Cerknica, surroundings of the water reservoir Medvedce and coastal wetlands. In 2008 and 2013 the Short-eared Owl occurred in large numbers, and these years were regarded as irruptive. Flocks of 2 to 8 birds were observed. At Ljubljansko barje, increased numbers of observed Short-eared Owls coincided with a large population of small mammals (species of the genus Apodemus and Microtus) and poor snow cover in 2008, and at least three communal roost sites were found that year. In the irruptive year 2013 there was a greater number of Short-eared Owls observed at the Medvedce water reservoir. On the plain at Lesce near the village of Smokuč an injured second year female was found at the end of March 2008 with a developing brood patch in its initial stage. It is likely that the female attempted to nest, which confirms the status of the species as occasional breeder in Slovenia. The last confirmed breeding in Slovenia was recorded in 1936 at Ljubljansko barje. In addition to local conditions (population of small mammals, snow cover) the frequency of occurrence of the Short-eared Owl in Slovenia is also affected by the population of development in the Boreal region and changes in migratory characteristics of the species in Europe. Therefore, an increase of the number of Short-eared Owls in Slovenia is expected in the future, as well as breeding attempts by this nomadic owl in seasons with high populations of small mammals and green winters, of course, if appropriate meadow habitat is still preserved.

Diet of Short-eared OwlAsio flammeus(Pontoppidan, 1763) in desert area at Hassi El Gara (El Golea, Algeria)

AbstractThe diet of the Short-eared Owl Asio flammeus was analysed in an arid environment in Hassi El Gara located in the southeast of El Golea (Ghardaia, Algeria). The diet was determined by analysing 138 pellets. Our data showed that the diet was dominated by mammals (Chiroptera and Rodentia). Based on relative biomass, birds were the main prey species. Mammals were the second most important prey. Mammals were the major food item throughout the seasons and their contribution to the diet ranged from 50.7% in spring to 73.6% in summer. Birds were the second numerous prey with 8.1% in summer and 29.6% in spring. The dominant prey species was Myotis sp., making up 37.8%. It was followed by Gerbillus nanus (5.4%), Columba livia (4.3%) and Bufo mauritanicus (4.1%).

Prioritising Research in Steppe Bird Conservation: A Literature Survey

With the aim to identify priorities in conservation-oriented research, this paper reviews the level of scientific attention given to steppe birds in Spain during the last 50 years. We surveyed scientific literature using Thomson Reuters Web of Science and the journal Ardeola, using the English names of 28 species of steppe birds and the word “Spain” as search terms. Every species was assigned a Scientific Attention Index (SAI), based on the number of articles published on each of them. In addition, a vulnerability measure (Vulnerability Score; VS) was calculated for each species on the basis of the trend estimate provided by the Sacre or Noctua monitoring programmes, or according to expert criteria. The sample gathered (432 articles) was a significant and thus representative proportion of WOS and Ardeola contents on the species considered. The most studied species was the red-legged partridge Alectoris rufa, with 83 papers (20.15%); while the least studied was the short-eared owl Asio flammeus (1 paper; 0.24%). The most studied knowledge area was Habitat Selection (92 papers; 22.17%), while the least was Niche/Climate, with nine papers (2.17%). Preferred habitat (grass steppe, shrub steppe or mixed) was not a significant factor in the level of scientific attention given to the different species. However, large-sized species (non-Passerines) were significantly more studied than small-sized ones (Passerines), indicating a research bias for the former group. Finally, no significant relationship was found between SAI and VS, which suggests that research effort has been allocated irrespective of the species' conservation status. These results highlight the scarce scientific attention given to most steppe birds in Spain in spite of their overall high vulnerability, and for most of the knowledge areas considered. On the other hand, they also show the high relative importance of research carried out in Spain, in both the Mediterranean and world contexts. This work underscores the need to focus scientific effort on certain species, especially those that currently show more regressive trends or higher levels of vulnerability, and in most areas of knowledge.

Aspects of the Breeding Ecology of Short-eared Owls (Asio flammeus) on Amherst and Wolfe Islands, Eastern Ontario

Aspectos de la Ecologia Reproductiva de Asio flammeus en las Islas Amherst y Wolfe, Este de Ontario A pesar de su estatus como una especie de preocupacion de manejo a traves de gran parte de Norte America, se conoce relativamente poco sobre la ecologia reproductiva de Asio flammeus. Estudiamos la ecologia reproductiva de siete territorios de cria en dos islas en el este de Ontario durante 2009 y 2010. Cada ano, los territorios de cria estuvieron agrupados en localizaciones distintivas en la Isla Amherst. Cinco de los siete territorios estuvieron ubicados en pastizales con pastoreo y proximos a cercas de postes de madera y cercas de alambre de rejilla. De los cuatro nidos encontrados, todos estuvieron a menos de 540 metros de un humedal y a 1500 metros de una vivienda humana. Al parecer, los nidos se ubicaron selectivamente en sitios con vegetacion que brindaba un alto grado de ocultamiento. Los pastos constituyeron el 70% de la vegetacion en estos nidos, con contribuciones menores de hierbas (25%) y suelo...

Genetic divergence analysis of the Common Barn Owl Tyto alba (Scopoli, 1769) and the Short-eared Owl Asio flammeus (Pontoppidan, 1763) from southern Chile using COI sequence.

In this paper new mitochondrial COI sequences of Common Barn Owl Tyto alba (Scopoli, 1769) and Short-eared Owl Asio flammeus (Pontoppidan, 1763) from southern Chile are reported and compared with sequences from other parts of the World. The intraspecific genetic divergence (mean p-distance) was 4.6 to 5.5% for the Common Barn Owl in comparison with specimens from northern Europe and Australasia and 3.1% for the Short-eared Owl with respect to samples from north America, northern Europe and northern Asia. Phylogenetic analyses revealed three distinctive groups for the Common Barn Owl: (i) South America (Chile and Argentina) plus Central and North America, (ii) northern Europe and (iii) Australasia, and two distinctive groups for the Short-eared Owl: (i) South America (Chile and Argentina) and (ii) north America plus northern Europe and northern Asia. The level of genetic divergence observed in both species exceeds the upper limit of intraspecific comparisons reported previously for Strigiformes. Therefore, this suggests that further research is needed to assess the taxonomic status, particularly for the Chilean populations that, to date, have been identified as belonging to these species through traditional taxonomy.

Nesting and non-nesting occurrence of the short-eared owl Asio flammeus in the Záhorie region (SW Slovakia)

Abstract The short-eared owl is a regular migrant and hibernant in the Záhorie region (SW Slovakia), though this species mostly escapes attention. In 1998 the species was found nesting in this region, and in 2012 individuals showing territorial behaviour were regularly observed, with high probability of nesting. Nesting habitats were localities with a high representation of meadows, corresponding to the preferred nesting sites in Slovakia. The foraging range of wintering birds was comparable with those from neighbouring regions (W Slovakia, Hungary), but with a higher number of harvest mice Micromys minutus and long-tailed field mice Apodemus sylvaticus. In both years when the nesting of birds was recorded, snowfall was significantly lower. Food sources were not monitored at these localities.

Diurnal and nocturnal ranging behaviour by moorland-breeding Short-eared Owls Asio flammeus in Scotland

Capsule The total area encapsulated by the hunting ranges of breeding Short-eared Owls Asio flammeus was broadly similar between day and night and also through the season, but activity was concentrated more on lower altitude graminoid-dominated areas during daylight and early in the breeding season. Aims To assess the representativeness of diurnal observations alone for determining ranging behaviour and habitat-use of breeding Short-eared Owls. Methods The diurnal and nocturnal ranging behaviours of four radiotagged Short-eared Owls were compared. Further diurnal field observations were used to assess the representativeness of the behaviour of the radiotagged birds. Results Short-eared Owls tended to hunt more over higher ground (where there was a greater ericaceous component within the moorland vegetation) at night and also later in the breeding season; the area of the total hunting range remained similar through the season (mean about 200 ha). Nocturnal activity rates closely matched those during peak diurnal activity periods. Conclusion Diurnal observations of breeding Short-eared Owls could provide representative data to inform breeding population densities and distribution but they may not be representative of overall habitat-use or ranging behaviour within home-ranges. Assessments of the risks to breeding Short-eared Owls of developments on moorland (e.g. forestry, wind turbine construction, grazing changes) based on diurnal observations alone may not reflect the true scale of potential impacts, which would also need to consider nocturnal behaviour.

Diet of short-eared owls <i>Asio flammeus</i> over seven winters in County Cork, Ireland

Previous studies of short-eared owl Asio flammeus (Pontoppidan) diet in Ireland have all been relatively small in scale and restricted in time. A total of 759 prey items were recovered and identified for this study during six winters (2005/2006-2010/2011). A further 271 prey items collected by the same authors in 2004/2005 for a previous study makes this the largest body of work on the prey of short-eared owls carried out in Ireland to date at 1030 prey items. Bird prey made up 55.9% by number and 83.1% by weight, and mammal prey made up 42.4% by number and 16.9% by weight. Thirteen invertebrates were also recovered. Dunlin Calidris alpina (L.) was the most frequently taken bird species, followed by snipe Gallinago gallinago (L.) and redshank Tringa totanus (L.). Together, these three wading birds formed 62.2% of prey by weight. Passerine birds were also taken, but only the thrush family ( Turdus spp), collectively, was of any importance at 10.1% of prey by weight. The wood mouse Apodemus sylvaticus (L.) was the most frequently taken mammal species (8.2% by weight), while smaller numbers of other rodents and shrews were taken. Dunlin was an important prey species up to February, but declined thereafter, while snipe and redshank remained important throughout the winter. Passerine birds were also taken throughout the period, but their overall contribution was lower than that of wading birds. Brown rats Rattus norvegiens (Berkenhout) and small mammals were taken throughout, but their monthly contribution was generally below 20%, except for one occasion in April in one year. Chi-square tests showed significant differences in some prey species and categories between months and years. While the reasons for some of the differences remain unknown, others are related to prey numbers available in any given month. There is also a suggestion that the severe winter of 2010/2011 influenced the higher than expected number of dunlin, and the lower than expected number of small mammals taken as prey in that winter.

DIET OF SHORT-EARED OWLS ASIO FLAMMEUS OVER SEVEN WINTERS IN COUNTY CORK, IRELAND

Previous studies of short-eared owl Asio flammeus (Pontoppidan) diet in Ireland have all been relatively small in scale and restricted in time. A total of 759 prey items were recovered and identified for this study during six winters (2005/2006-2010/2011). A further 271 prey items collected by the same authors in 2004/2005 for a previous study makes this the largest body of work on the prey of short-eared owls carried out in Ireland to date at 1030 prey items. Bird prey made up 55.9% by number and 83.1% by weight, and mammal prey made up 42.4% by number and 16.9% by weight. Thirteen invertebrates were also recovered. Dunlin Calidris alpina (L.) was the most frequently taken bird species, followed by snipe Gallinago gallinago (L.) and redshank Tringa totanus (L.). Together, these three wading birds formed 62.2% of prey by weight. Passerine birds were also taken, but only the thrush family (Turdus spp), collectively, was of any importance at 10.1% of prey by weight. The wood mouse Apodemus sylvaticus (L.) was the most frequently taken mammal species (8.2% by weight), while smaller numbers of other rodents and shrews were taken. Dunlin was an important prey species up to February, but declined thereafter, while snipe and redshank remained important throughout the winter. Passerine birds were also taken throughout the period, but their overall contribution was lower than that of wading birds. Brown rats Rattus norvégiens (Berkenhout) and small mammals were taken throughout, but their monthly contribution was generally below 20%, except for one occasion in April in one year. Chi-square tests showed significant differences in some prey species and categories between months and years. While the reasons for some of the differences remain unknown, others are related to prey numbers available in any given month. There is also a suggestion that the severe winter of 2010/2011 influenced the higher than expected number of dunlin, and the lower than expected number of small mammals taken as prey in that winter.