| herpersvirus strigis: host spectrum and distribution in infected owls. | herpesvirus strigis, a new species of the genus herpesvirus, is a pathogen for several species of owls in the order srigiformes. natural infection has been observed in the eagle owl (bubo bubo l.), long-eared owl (asio otus l.) and snowy owl (nyctea scandiaca l.) in addition the little owl (athene noctua scopolic) and tengmalms owl (aegolius funereus l.) was experimentally infected. on the other hand the tawny owl (strix aluco l.) and barn owl (tyto albo scopoli) proved resistant to a massive ex ... | 1975 | 167204 |
| survey of blood parasites in two forest owls, northern saw-whet owls and flammulated owls, of western north america. | except for a few studies in the eastern united states, little has been published on hemoparasites in owls. we surveyed the blood parasites of 108 northern saw-whet owls (aegolius acadicus) and 24 flammulated owls (otus flammeolus) in idaho during autumn migration in 1999 and 2000. we also surveyed 15 flammulated owls (flow) during breeding season in utah from 2000. leucocytozoon ziemanni, haemoproteus syrnii, haemoproteus noctuae, and trypanosoma avium were identified. the overall prevalence of ... | 2008 | 18436683 |
| cycles in voles and small game in relation to variations in plant production indices in northern sweden. | population dynamics for voles (cricetidae), tengmalm's owl (aegolius funereus (l.)), red fox (vulpes vulpes (l.)) willow grouse (lagopus lagopus (l.)), black grouse (lyrurus tetrix (l.)), capercaillie (tetrao urogallus l.), hazel hen (tetrastes bonasia (l.)), mountain hare (lepus timidus l.) and tularemia (francisella tularensis (mccoy & chapin)) and game bird recruitment were studied by index methods in northern sweden. in addition contemporary temperature records and spruce (picea abies (l.) k ... | 1986 | 28311702 |
| declining ecosystem health and the dilution effect. | the "dilution effect" implies that where species vary in susceptibility to infection by a pathogen, higher diversity often leads to lower infection prevalence in hosts. for directly transmitted pathogens, non-host species may "dilute" infection directly (1) and indirectly (2). competitors and predators may (1) alter host behavior to reduce pathogen transmission or (2) reduce host density. in a well-studied system, we tested the dilution of the zoonotic puumala hantavirus (puuv) in bank voles (my ... | 2016 | 27499001 |
| selective predation on hantavirus-infected voles by owls and confounding effects from landscape properties. | it has been suggested that predators may protect human health through reducing disease-host densities or selectively preying on infected individuals from the population. however, this has not been tested empirically. we hypothesized that tengmalm's owl (aegolius funereus) selectively preys on hantavirus-infected individuals of its staple prey, the bank vole (myodes glareolus). bank voles are hosts of puumala hantavirus, which causes a form of hemorrhagic fever in humans. selective predation by o ... | 2016 | 26873607 |
| effects of predator removal on vertebrate prey populations: birds of prey and small mammals. | we studied the effects of removal of breeding nomadic avian predators (the kestrel, falco tinnunculus and tengmalm's owl, aegolius funereus) on small mammals (voles of the genera microtus and clethrionomys and the common shrew, sorex araneus) during 1989-1992 in western finland to find out if these predators have a regulating or limiting impact on their prey populations. we removed potential breeding sites of raptors from five manipulation areas (c. 3 km(2) each), whereas control areas had nest- ... | 1995 | 28306779 |
| does feeding effort of tengmalm's owls reflect offspring survival prospects in cyclic food conditions? | in an environment fluctuating in a predicatable manner with wide among-year variation in offspring mortality, fitness is largely influenced by the timing of reproductive investment. in vole-eating nocturnal tengmalm's owls (aegolius funereus), within-cycle variation in 1st-year survival of owlets is 3-fold as estimated by the recruitment probability of an offspring. it increases from the peak through the low to the increase phase of the vole cycle. we recorded prey delivery rates of males during ... | 1994 | 28313930 |
| home range size of tengmalm's owl during breeding in central europe is determined by prey abundance. | animal home ranges typically characterized by their size, shape and a given time interval can be affected by many different biotic and abiotic factors. however, despite the fact that many studies have addressed home ranges, our knowledge of the factors influencing the size of area occupied by different animals is, in many cases, still quite poor, especially among raptors. using radio-telemetry (vhf; 2.1 g tail-mounted tags) we studied movements of 20 tengmalm's owl (aegolius funereus) males duri ... | 2017 | 28545112 |
| hatching asynchrony and brood reduction in tengmalm's owl aegolius funereus: the role of temporal and spatial variation in food abundance. | hatching asynchrony is the consequence of birds initiating incubation before clutch completion. it has been suggested that variation in hatching asynchrony in owls is extensive, and therefore they should be excellent objects to study the effects of spatio-temporal variation in food abundance on this phenomenon. we examined how abundance and predictability of food affected hatching asynchrony in tengmalm's owl aegolius funereus (linnaeus), which mainly feeds on voles which fluctuate in 3- to 4-ye ... | 2002 | 28466218 |
| ophthalmic reference values and lesions in two captive populations of northern owls: great grey owls (strix nebulosa) and snowy owls (bubo scandiacus). | this study established ophthalmic reference values and characterized ocular lesions in two captive populations of boreal owls, including 46 eyes of 23 great grey owls (strix nebulosa) and 38 eyes from 19 snowy owls (bubo scandiacus). a complete ophthalmologic exam was conducted, including neuro-ophthalmic reflexes, schirmer tear test i (stt-i), intraocular pressure (iop) using rebound tonometry, fluorescein staining, horizontal corneal measurements using jameson calipers, direct and indirect oph ... | 2016 | 27010284 |
| laboratory blood analysis in strigiformes-part i: hematologic reference intervals and agreement between manual blood cell counting techniques. | while hematologic reference intervals (ri) are available for multiple raptorial species of the order accipitriformes and falconiformes, there is a lack of valuable hematologic information in strigiformes that can be used for diagnostic and health monitoring purposes. | 2015 | 25627556 |
| [parasite fauna of austrian owls (strigiformes)]. | during the examination of 182 owls--asio otus (51), strix aluco (44), bubo bubo (34), nyctea scandiaca (15), athene noctua (14), otus scops (9), tyto alba (4), aegolius funereus (3), glaucidium passerinum (2), asio flammeus (2), indigenous "owls" (4)--5 protozoan species, 3 trematode species, 1 cestode species, 6 nematode species, 3 acanthocephalan species, 2 acaride species and 7 insect species could be discovered. dermanyssus hirundinis was proved on the long-eared owl and carnus hemapterus on ... | 1982 | 7165130 |
| gradients in population fluctuations of tengmalm's owl aegolius funereus in europe. | i studied the importance of geographical location, snow cover and food to the fluctuations in 30 breeding populations of tengmalm's owl (aegolius funereu) in europe. cyclicity indices were positively related both to latitude and longitude, but within fennoscandia they were better correlated with snow cover. population fluctuations increased northward, while food niche breadth and degree of site tenacity decreased northwards.microtine fluctuations become more pronounced northwards and are more sy ... | 1986 | 28311358 |
| site tenacity and nomadism in tengmalm's owl (aegolius funereus (l.)) in relation to cyclic food production. | in northern sweden breeding males of tengmalm's owls (aegolius funereus (l.)) were site tenacious during and between the peaks of the vole (staple food) cycles, but females only during the peaks. most of these adults shifted nest boxes between successive years. they selected nest boxes randomly in a radius of 3 km. juveniles, in contrast to site tenacious adults, dispersed outside their natal area. the females moved longer than the males prior to their first breeding. five adult females were fou ... | 1986 | 28311331 |
| why do territorial male tengmalm's owls fail to obtain a mate? | non-breeding may occur because non-breeders are immature or somehow physiologically incapable of breeding, or because of a lack of resources (e.g. food resources, mating partners) needed to breed. there is, however, a lack of experimental evidence on whether bachelor males possessing territories and nest-sites are able to breed when supplemented with extra food or provided with mating partners. in vole-eating tengmalm's owl, aegolius funereus, we provided supplementary food and transferred femal ... | 1998 | 28307908 |
| sex ratio and fledging success of supplementary-fed tengmalm's owl broods. | a nest box population of tengmalm's owls (aegolius funereus) in northern sweden was studied to investigate the effects of extra food on the sex ratio between hatching and fledging in this sexually size-dimorphic species. the brood size and brood sex ratio of supplementary-fed and control broods were compared. newly hatched nestlings were blood sampled and sexed by polymerase chain reaction (pcr) amplification of the sex-linked chd1z and chd1w genes. the brood sex ratio at hatching was strongly m ... | 2000 | 10672162 |
| fading out of vole and predator cycles? | northern voles and lemmings are famous for their spectacular multiannual population cycles with high amplitudes. such cyclic vole populations in scandinavia have shown an unexpected and marked long-term decline in density since the early 1970s, particularly with a marked shift to lower spring densities in the early 1980s. the vole decline, mainly characterized by a strongly decreased rate of change in numbers over winter, is associated with an increased occurrence of mild and wet winters brought ... | 2005 | 16191615 |
| female offspring desertion and male-only care increase with natural and experimental increase in food abundance. | in species with biparental care, one parent may escape the costs of parental care by deserting and leaving the partner to care for the offspring alone. a number of theoretical papers have suggested a link between uniparental offspring desertion and ecological factors, but empirical evidence is scarce. we investigated the relationship between uniparental desertion and food abundance in a natural population of tengmalm's owl aegolius funereus, both by means of a 5-year observational study and a 1- ... | 2009 | 19324835 |
| habitat selection as an antipredator behaviour in a multi-predator landscape: all enemies are not equal. | 1. breeding territory choice constitutes a crucial antipredator behaviour for animals that determines reproductive success and survival during the breeding season. on arrival to breeding grounds migrant prey face a multitude of 'waiting' predators already settled within the landscape. 2. we studied territory selection and reproductive investment of migrant pied flycatcher (ficedula hypoleuca) relative to breeding pygmy owls (pos) (glaucidium passerinum) and tengmalm's owls (tos) (aegolius funere ... | 2010 | 19912426 |
| the impact of climate and cyclic food abundance on the timing of breeding and brood size in four boreal owl species. | the ongoing climate change has improved our understanding of how climate affects the reproduction of animals. however, the interaction between food availability and climate on breeding has rarely been examined. while it has been shown that breeding of boreal birds of prey is first and foremost determined by prey abundance, little information exists on how climatic conditions influence this relationship. we studied the joint effects of main prey abundance and ambient weather on timing of breeding ... | 2011 | 20665047 |
| emaciation and larval filarioid nematode infection in boreal owls (aegolius funereus). | microfilariae are considered non-pathogenic in wild birds. the objective of the current communication is to report host reactions to microfilarial infection of unusual intensity in emaciated boreal owls (aegolius funereus). an unusually large number of boreal owls (n = 21) were submitted to the canadian cooperative wildlife health center-quebec region for post-mortem examination during the winter of 2009. nineteen out of 21 birds were considered emaciated based on atrophy of adipose tissue and p ... | 2012 | 22834547 |
| differential movement patterns of juvenile tengmalms owls (aegolius funereus) during the post-fledging dependence period in two years with contrasting prey abundance. | fledgling behaviour and movement patterns throughout the post-fledging dependence period (pfdp), especially in relation to changing environmental conditions, have been rarely studied, despite the fact that this period is recognized as of crucial significance in terms of high mortality of juveniles. the pfdp can extend over quite a protracted period, particularly in birds of prey, and a knowledge of the movement patterns of individuals is fundamental for understanding mechanisms underlying surviv ... | 2013 | 23843981 |
| dna barcoding as a tool for elucidating species delineation in wide-ranging species as illustrated by owls (tytonidae and strigidae). | the mitochondrial cytochrome c-oxidase subunit i (cox1) can serve as a fast and accurate marker for the identification of animal species, and for the discovery of new species across the tree of life. distinguishing species using this universal molecular marker, a technique known as dna barcoding, relies on the identifying the gap between intra- and interspecific divergence. one of the difficulties could be wide-ranging, cosmopolitan species that show large amounts of morphological variation. the ... | 2013 | 24199866 |
| factors affecting vocalization in tengmalm's owl (aegolius funereus) fledglings during post-fledging dependence period: scramble competition or honest signalling of need? | begging behaviour of nestlings has been intensively studied for several decades as a key component of parent-offspring conflict. there are essentially two main theories to account for intensity of food solicitation among offspring: that intensity of begging is related to some form of scramble competition between nest mates or that it offers honest signalling of need to parents. the vast majority of studies which have addressed begging behaviour have been based on observations of, and experiments ... | 2014 | 24760102 |
| perching of tengmalm's owl (aegolius funereus) nestlings at the nest box entrance: effect of time of the day, age, wing length and body weight. | the behaviour of the nestlings of nocturnal cavity-nesting species has relatively rarely been studied in detail because of problems connected with use of the technical devices required to provide long-term monitoring of individuals. however, long-term observation of nestling behaviour is crucial in order to identify different types of behaviour which may be caused by sibling competition at the end of nesting period. we studied behaviour of 43 tengmalm's owl (aegolius funereus) nestlings at 14 ne ... | 2014 | 24828567 |
| brood size manipulations in a spatially and temporally varying environment: male tengmalm's owls pass increased reproductive costs to offspring. | a key tool used to assess reproductive trade-offs in birds is brood size manipulation (bsm) experiments. most bsm studies have examined the influence on short-term measures of reproductive output. seldom evaluated are the effects on long-term fitness proxies under temporally or spatially varying environments. unpredictable environments may affect reproductive trade-offs by altering the value of the brood or hampering optimization of reproductive effort. we reduced or enlarged broods of 140 male ... | 2014 | 25080177 |
| factors affecting the duration of nestling period and fledging order in tengmalm's owl (aegolius funereus): effect of wing length and hatching sequence. | in altricial birds, the nestling period is an important part of the breeding phase because the juveniles may spend quite a long time in the nest, with associated high energy costs for the parents. the length of the nestling period can be variable and its duration may be influenced by both biotic and abiotic factors; however, studies of this have mostly been undertaken on passerine birds. we studied individual duration of nestling period of 98 tengmalm's owl chicks (aegolius funereus) at 27 nests ... | 2015 | 25793880 |
| haemosporidian infections in the tengmalm's owl (aegolius funereus) and potential insect vectors of their transmission. | sedentary bird species are suitable model hosts for identifying potential vectors of avian blood parasites. we studied haemosporidian infections in the tengmalm's owl (aegolius funereus) in the ore mountains of the czech republic using molecular detection methods. sex of owl nestlings was scored using molecular sexing based on fragment analysis of pcr-amplified chd1 introns. observed infection prevalences in nestlings and adult owls were 51 and 86 %, respectively. five parasite lineages were det ... | 2016 | 26365667 |
| factors affecting growth of tengmalm's owl (aegolius funereus) nestlings: prey abundance, sex and hatching order. | in altricial birds, energy supply during growth is a major predictor of the physical condition and survival prospects of fledglings. a number of experimental studies have shown that nestling body mass and wing length can vary with particular extrinsic factors, but between-year observational data on this topic are scarce. based on a seven-year observational study in a central european tengmalm's owl population we examine the effect of year, brood size, hatching order, and sex on nestling body mas ... | 2015 | 26444564 |
| survival of male tengmalm's owls increases with cover of old forest in their territory. | the loss and fragmentation of forest habitats have been considered to pose a worldwide threat to the viability of forest-dwelling animals, especially to species that occupy old forests. we investigated whether the annual survival of sedentary male tengmalm's owls aegolius funereus was associated with the cover of old coniferous forests in finland. survival and recapture probabilities varied annually with density changes in populations of the main prey (microtus voles). when this variation was co ... | 2008 | 18080142 |
| blood parasites and nest defense behaviour of tengmalm's owls. | infectious diseases are expected to negatively influence essential life history traits of an individual, because investment in immunological response occurs at the expense of reduced investment in other functions. here we present the first observational evidence that the prevalence of blood parasites is negatively associated with avian nest defense. because the defense of offspring entails a risk of serious physical harm to the parent, it is also assumed to be a good estimate of parental investm ... | 1998 | 28307907 |
| lifetime reproduction of a forest-dwelling owl increases with age and area of forests. | loss and alteration of habitats by human actions are the largest worldwide hazard to biodiversity and viability of populations. in boreal forests of eurasia and north america the natural habitat is changing, mainly because of forestry practices and agriculture. although there is evidence that the diversity and abundance of animal species are lower in intensively managed than in natural forests, very little is known about how the changes in habitat composition affect reproduction and survival. th ... | 2004 | 15801604 |
| trypanosomes of some sub-saharan birds. | linear measurements and derived indices from striated trypanosomes in nine species of sub-saharan birds representing seven families of the passeriformes, were compared. the dimensions of the striated trypomastigotes from the carduelinae, estrildidae, nectarinidae, passeridae, pycnonotidae, turdinae and zosteropidae were similar to each other as well as to those of the striated trypanosomes from the boreal owl (strigidae). all these trypanosomes were considered to be trypanosoma avium danilewsky, ... | 1994 | 7596580 |
| experimental increase of predation risk induces breeding dispersal of tengmalm's owl. | nest predation and its avoidance are critical components of an individual's fitness and play an important role in life history evolution. almost all studies on this topic have been observational, and thus have not been able to separate the effects of individual quality, habitat selection and predation risk of given nest sites from each other. more experimental studies on nest predation and breeding dispersal, therefore, are needed to avoid confusing interpretations of the results. in western fin ... | 2001 | 28547448 |
| selective predation by owls on infected bank voles (myodes glareolus) as a possible sentinel of tularemia outbreaks. | tularemia is a widely spread zoonotic disease in the northern hemisphere, caused by the bacterium francisella tularensis. in humans, tularemia is an acute febrile illness with incidence peaks in late summer to early autumn of outbreak years, but there is no early warning system in place that can reduce the impact of disease by providing timely risk information. in this study, we revisit previously unpublished data on f. tularensis in water, sediment, soil, and small mammals from 1984 in northern ... | 2020 | 32349636 |
| owls lack uv-sensitive cone opsin and red oil droplets, but see uv light at night: retinal transcriptomes and ocular media transmittance. | most diurnal birds have cone-dominated retinae and tetrachromatic colour vision based on ultra-violet/violet-sensitive uv/v cones expressing short wavelength-sensitive opsin 1 (sws1), s cones expressing short wavelength-sensitive opsin 2 (sws2), m cones expressing medium wavelength-sensitive opsin (rh2) and l cones expressing long wavelength-sensitive opsin (lws). double cones (d) express lws but do not contribute to colour vision. each cone is equipped with an oil droplet, transparent in uv/v c ... | 2019 | 30825468 |
| species interactions and climate change: how the disruption of species co-occurrence will impact on an avian forest guild. | interspecific interactions are crucial in determining species occurrence and community assembly. understanding these interactions is thus essential for correctly predicting species' responses to climate change. we focussed on an avian forest guild of four hole-nesting species with differing sensitivities to climate that show a range of well-understood reciprocal interactions, including facilitation, competition and predation. we modelled the potential distributions of black woodpecker and boreal ... | 2020 | 31804736 |
| ear asymmetry in tengmalm's owl (aegolius funereus): two phases of asymmetrical development of the squamoso-occipital wing. | ear asymmetry is an adaptive characteristic present in the order of owls (strigiformes). it developed independently up to seven times in this taxon and is accompanied by morphological adaptations in bones or soft tissues around or at the ear openings. within all strigiform species, the boreal or tengmalm's owl (aegolius funereus) possesses a particularly complex bilateral ear asymmetry that results from modifications of the neurocranium and some cartilaginous elements. while the ear asymmetry in ... | 2020 | 32629330 |