Barn Owl

This description of the diet of Asio flammeus (Short-eared Owl) in Oklahoma is based on prey remains identified in 4,281 Short-eared Owl pellets collected by Paul Wilson from 1982-2005. Also included in the list are prey items of Short-eared Owls in Oklahoma reported in the literature. The pellets contained 3 species of birds and 9 species of small mammals. Our results combined with those in the previously published reports produced a list of 22 different prey items for the Short-eared Owl in Oklahoma.

The development of daily rhythmicity in Barn Owls (Tyto alba) The development of biorhythms is an important aspect of the dynamic interaction between the young animal and its environment. The study of such phenomena gives an insight into general evolutionary characteristics of development as well as into species-specific features. Biorhythms depend on a maturated intact central nervous system which works as a pacemaker and on fully developed sensory organs which give the synchronising input for the neuronal rhythm generator. While there is extensive knowledge of adult biorhythms, information on the ontogeny of such rhythms is limited. Video records of Barn Owl nestlings were analysed with regard to their development of rest/activity rhythms. Barn Owls are altricial birds; at birth they are nearly immobile, their eyes are closed and they are unable to feed by themselves. The analysis was made on nestlings of different age classes. At the age of 20 days the share of the 24h-period taken up by the locomotory activity of the nestlings was 11±13 %. A lot of ultradian rhythms were detected. They caused the typical polymodal pattern of the daily activity. In 30 day old nestlings the share of the 24h-span was 16±18 % and at the age of 45 days it was 20±22 %. This increase within the 24h-period is typical of the ontogeny of locomotory activity and is described in literature in mammals as well as in birds .

Fossil evidence indicates that owls have been preying on bats from as far back as the Pleistocene. Overall, bats form quite small portions (i.e. trace to 0.2%) of the diets (by prey frequency) of European owls. An assessment of dietary studies and anecdotal accounts reveals that five species of European owls, the Eurasian scops owl Otus scops, Pygmy owl Glaucidium passerinum, Tengmalm's owl Aegolius funereus, little owl Athene noctua and Ural owl Strix uralensis, rarely feed on bats (with less than 0.1-0.4%) and a further two species, short-eared owl Asio flammeus and eagle owl Bubo bubo, may only take bats occasionally, while three species, long-eared owl Asio otus, barn owl Tyto alba and tawny owl Strix aluco, feed on bats more frequently. In this study, a total of 19,864 recorded bats have been preyed upon by these owls, with as many as 48 bat species being identified. Barn and tawny owls have captured most of this total (47.1 and 41.9%), followed by the long-eared owl (7.6%), while short-eared and eagle owls take similar amounts of bats (1.1 and 1.7%, respectively). Owl predation on bats deserves future research because it may help contribute to our knowledge on bat biodiversity and distribution and possibly identify an additional risk for small populations of endangered bats.

Journal of Threatened Taxa is dedicated to building evidence for conservation globally by publishing peer-reviewed articles online every month at a reasonably rapid rate at www.threatenedtaxa.org. All articles published in JoTT are registered under Creative Commons Attribution 4.0 International License unless otherwise mentioned. JoTT allows unrestricted use of articles in any medium, reproduction, and distribution by providing adequate credit to the authors and the source of publication.

Author(s): Shore, R. F.; Potter, E. D.; Walker, L. A.; Pereira, M. G.; Chaplow, J. S.; Jaffe, J. E.; Sainsbury, A. W.; Barnett, E. A.; Charman, S.; Jones, A.; Giela, A.; Senior, C.; Sharp, E. A. | Abstract: Secondary exposure of predators to anticoagulant rodenticides, and in particular second generation anticoagulant rodenticides (SGARs), is a global phenomenon. The widespread and large-scale nature of this exposure has attracted considerable concern, although the consequences in terms of likelihood of poisoning of individuals and resultant impacts on populations are not well characterised. Secondary exposure of predators may as rise from once or more of: (i) eating contaminated commensal rodents subject to control (target species are typically rats and house mice); (ii) consumption of contaminated non-target small mammals (such as Peromyscus, Microtus, and Apodemus species) that encounter and feed on what are rodent-attractive baits; (iii) consumption of non-rodent vertebrate and ...

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By producing pellets rich in micromammal remains, owls are important contributors to small vertebrate accumulations in archaeological sites. Neotaphonomic studies are necessary to evaluate predation and fossilization biases before using pellet-derived assemblages to assess palaeoenvironmental reconstructions and micromammal community changes in plio-quaternary deposits. In this study, barn owl (Tyto alba) pellets were collected from two localities of Botswana with markedly different environments: the northern Kalahari (arid) and the Okavango Delta (humid). The taxonomic and taphonomic analyses of the two samples were compared with data from the literature on other T. alba pellet assemblages from Sub-Saharan Africa. This study provides additional data for the wildlife inventory at a local scale and further information about the diet and hunting habits of Tyto alba in this area, as well as its taphonomic impact on local rodent species. It confirms that barn owl assemblages are reliably good indicators of local environmental conditions. An application of palaeoecological methods was also made in order to evaluate the accuracy and performance of palaeoenvironmental reconstructions based on micromammal assemblages produced by owls in an archaeological context. Here, we discuss some methodological issues facing micromammal studies in southern Africa.

Dietary studies are one of the most developed research areas in biology and ecology studies of Neotropical owls, but most of these studies have focused on few species. Our study describes the diet of Barn Owl (Tyto alba), Spectacled Owl (Pulsatrix perspicillata), and Rufous-banded Owl (Strix albitarsis) in Jardin and Ciudad Bolivar, western Andes of Colombia. The diet of T. alba, based on 495 prey items consisted 98.6% of vertebrates, the main food items being rodents (66%) and shrews (21.4%). Out of 142 prey items identified from P. perspicillata fractured pellets, the main prey species were Artibeus lituratus (23.9%), Rattus norvegicus (21.8%), and Didelphis sp. (16.1%), species of small and medium-sized mammals that tolerate environmental changes and often live in urban areas. Pulsatrix perspicillata preyed also on at least 14 bird species including hummingbirds and migratory birds. Based on 165 prey items S. albitarsis consumed more invertebrates (57.7%) than vertebrates (42.3%). Among the insects, the main preys were Coleoptera beetles and Orthoptera crickets. Among the vertebrates, the main prey species included mammals such as Thomasomys aureus, Marmosops sp., Marmosa sp., and Reithrodontomys mexicanus. These scansorial species are likely to be vulnerable to aerial predators such as S. albitarsis which hunt from a perchs. According to standardized Levins index values T. alba was the most selective in its food habits, P. perspicillata had intermediate values, while S. albitarsis showed the least selective diet. RESUMEN • Dieta de la Lechuza Común (Tyto alba), el Búho de Anteojos (Pulsatrix perspicillata) y el Búho Ocelado (Strix albitarsis) en la cordillera Occidental de Colombia Los estudios sobre hábitos tróficos constituyen la línea de investigación más desarrollada dentro de la biología y ecología de los búhos Neotropicales, pero la mayoría de esos estudios se han centrado en pocas especies. El propósito de este estudio es describir la dieta de la Lechuza Común (Tyto alba), el Búho de Anteojos (Pulsatrix perspicillata) y el Búho Ocelado (Strix albitarsis), en Jardín y Ciudad Bolívar, cordillera Occidental de Colombia. Identificamos 495 presas consumidas por T. alba. Su dieta estuvo compuesta en un 98.7% de vertebrados, principalmente roedores (66%) y musarañas (21.4%). De 142 presas de P. perspicillata, las presas principales, Artibeus lituratus (23.9%), Rattus norvegicus (21.8%) y Didelphis sp. (16.1%), son especies tolerantes a los ambientes intervenidos y hacen parte de los ensamblajes de pequeños mamíferos encontrados en ambientes urbanos. Pulsatrix perspicillata consumió también al menos 14 especies de aves incluyendo colibríes y aves migratorias. En base a 165 presas S. albitarsis consumió más invertebrados (57.7%) que vertebrados (42.3%). Entre los insectos depredó en mayor porcentaje los ordenes Coleoptera y Orthoptera, mientras que entre los vertebrados predominaron los de hábitos escansoriales (Thomasomys aureus, Marmosops sp., Marmosa sp. y Reithrodontomys mexicanus). Estos vertebrados serían más vulnerables a depredadores aéreos como S. albitarsis, la cual caza desde perchas en árboles. De acuerdo a los valores obtenidos para el indice estandarizado de Levins, T. alba fue más selectiva en el consumo de las presas, seguida por P. perspicillata, mientras que S. albitarsis tiene la dieta menos selectiva.

Madagascar Teal Anas bernieri were captured at Lake Antsamaka, central-western Madagascar, during the species' annual wing moult to test whether the sexes could be differentiated on morphometrics and report on a little-known species. A total of 345 birds were caught, measured and ringed over a 13 year period (1997-2009), of which 73 were recaptured. Males and females did not differ significantly in body mass; for other body measurements (tarsus, culmen and skull) males were significantly larger. Body mass did not change significantly with wing length for moulting birds re-growing their feathers, implying an adequate food supply to maintain mass during moult at the site. Wing length increased linearly at a rate of 5.72 mm/day in individuals recaptured 1-8 days after first being caught, indicative of feather growth over this period, with growth rates stabilising and diminishing thereafter. One adult female (aged at least 2 years) was caught eight years after first capture, indicating that Madagascar Teal can reach an age of at least 10 years in the wild. Individuals caught and ringed during moult moved up to c. 200 km from the ringing site. Declines in numbers moulting at Lake Antsamaka during our study were linked to water depth at the site, which is in turn apparently linked to annual precipitation. Conservation of this species requires protection of the population in several watersheds and at moulting sites where it is very vulnerable to disturbance, capture for food by local people and predation.

Interaural time differences (ITDs) are one of the cues used for binaural sound localisation. In birds, ITDs are computed in nucleus laminaris (NL), where a place code of azimuthal location first emerges. In chickens, NL consists of a monolayer of bitufted cells that receive segregated inputs from ipsi-and contralateral nucleus magnocellularis (NM). In barn owls, the monolayer organisation, the bitufted morphology, and the segregation of inputs have been lost, giving rise to a derived organisation that is accompanied by a reorganisation of the auditory place code. Although chickens and barn owls have been the traditional experimental models in which to study ITD coding, they represent distant evolutionary lineages with very different auditory specialisations. Here we examined the structure of NL in several bird lineages. We have found only two NL morphotypes, one of which appears to have emerged in association with high frequency hearing.

The Shaw-like potassium channel Kv3.1, a delayed rectifier with a high threshold of activation, is expressed in the time coding nuclei of the bird auditory brainstem. In both barn owls and chickens, Kv3.1 mRNA was expressed in the cochlear nucleus magnocellularis (NM) and the nucleus laminaris (NL). Western blot analysis showed that an antibody raised against the synthetic peptide sequence of rat Kv3.1 (rKv3.1) specifically recognized the same 92 kDa protein bands in both rat and chicken synaptosomal preparations. Immunohistochemical analyses using this anti-rKv3.1 antibody revealed a prominent gradient in Kv3.1 immunoreactivity along the tonotopic axis of the barn owl NM and NL and a less prominent gradient in the chicken. The precise localization of the Kv3.1 immunoproduct was resolved by electron microscopy. In both the owl and the chicken, Kv3.1 was targeted postsynaptically in NM and NL. The major difference in localization of Kv3.1 protein between the two birds was the express...

Axons from the nucleus magnocellularis form a presynaptic map of interaural time differences (ITDs) in the nucleus laminaris (NL). These inputs generate a field potential that varies systematically with recording position and can be used to measure the map of ITDs. In the barn owl, the representation of best ITD shifts with mediolateral position in NL, so as to form continuous, smoothly overlapping maps of ITD with iso-ITD contours that are not parallel to the NL border. Frontal space (0°) is, however, represented throughout and thus overrepresented with respect to the periphery. Measurements of presynaptic conduction delay, combined with a model of delay line conduction velocity, reveal that conduction delays can account for the mediolateral shifts in the map of ITD.

Inputs from the two sides of the brain interact to create maps of interaural time difference (ITD) in the nucleus laminaris of birds. How inputs from each side are matched with high temporal precision in ITD-sensitive circuits is unknown, given the differences in input path lengths from each side. To understand this problem in birds, we modeled the geometry of the input axons and their corresponding conduction velocities and latencies. Consistent with existing physiological data, we assumed a common latency up to the border of nucleus laminaris. We analyzed two biological implementations of the model, the single ITD map in chickens and the multiple maps of ITD in barn owls. For binaural inputs, since ipsi- and contralateral initial common latencies were very similar, we could restrict adaptive regulation of conduction velocity to within the nucleus. Other model applications include the simultaneous derivation of multiple conduction velocities from one set of measurements and the dem...

Interaural time difference is an important cue for sound localization. In the barn owl (Tyto alba) neuronal sensitivity to this disparity originates in the brainstem nucleus laminaris. Afferents from the ipsilateral and contralateral magnocellular cochlear nuclei enter the nucleus laminaris through its dorsal and ventral surfaces, respectively, and interdigitate in the nucleus. Intracellular recordings from these afferents show orderly changes in conduction delay with depth in the nucleus. These changes are comparable to the range of interaural time differences available to the owl. Thus, these afferent axons act as delay lines and provide anatomical and physiological bases for a neuronal map of interaural time differences in the nucleus laminaris.

The auditory and electrosensory systems contain circuits that are specialized for the encoding and processing of microsecond time differences. Analysis of these circuits in two specialists, weakly electric fish and barn owls, has uncovered common design principles and illuminated some aspects of their evolution.

The neurophonic potential is a synchronized frequency-following extracellular field potential that can be recorded in the nucleus laminaris (NL) in the brainstem of the barn owl. Putative generators of the neurophonic are the afferent axons from the nucleus magnocellularis, synapses onto NL neurons, and spikes of NL neurons. The outputs of NL, i.e., action potentials of NL neurons, are only weakly represented in the neurophonic. Instead, the inputs to NL, i.e., afferent axons and their synaptic potentials, are the predominant origin of the neurophonic (Kuokkanen PT, Wagner H, Ashida G, Carr CE, Kempter R. J Neurophysiol 104: 2274–2290, 2010). Thus in NL the monaural inputs from the two brain sides converge and create a binaural neurophonic. If these monaural inputs contribute independently to the extracellular field, the response to binaural stimulation can be predicted from the sum of the responses to ipsi- and contralateral stimulation. We found that a linear summation model expla...

In the auditory system, precise encoding of temporal information is critical for sound localization, a task with direct behavioral relevance. Interaural timing differences are computed using axonal delay lines and cellular coincidence detectors in nucleus laminaris (NL). We present morphological and physiological data on the timing circuits in the emu, Dromaius novaehollandiae, and compare these results with those from the barn owl (Tyto alba) and the domestic chick (Gallus gallus). Emu NL was composed of a compact monolayer of bitufted neurons whose two thick primary dendrites were oriented dorsoventrally. They showed a gradient in dendritic length along the presumed tonotopic axis. The NL and nucleus magnocellularis (NM) neurons were strongly immunoreactive for parvalbumin, a calcium-binding protein. Antibodies against synaptic vesicle protein 2 and glutamic acid decarboxlyase revealed that excitatory synapses terminated heavily on the dendritic tufts, while inhibitory terminals were distributed more uniformly. Physiological recordings from brainstem slices demonstrated contralateral delay lines from NM to NL. During whole-cell patch-clamp recordings, NM and NL neurons fired single spikes and were doubly-rectifying. NL and NM neurons had input resistances of 30.0 ± 19.9 MΩ and 49.0 ± 25.6 MΩ, respectively, and membrane time constants of 12.8 ± 3.8 ms and 3.9 ± 0.2 ms. These results provide further support for the Jeffress model for sound localization in birds. The emu timing circuits showed the ancestral (plesiomorphic) pattern in their anatomy and physiology, while differences in dendritic structure compared to chick and owl may indicate specialization for encoding ITDs at low best frequencies.

The detection of interaural time differences underlies azimuthal sound localization in the barn owl. Sensitivity to these time differences arises in the brainstem nucleus laminaris. Auditory information reaches the nucleus laminaris via bilateral projections from the cochlear nucleus magnocellularis. The magnocellular inputs to the nucleus laminaris act as delay lines to create maps of interaural time differences. These delay lines are tapped by postsynaptic coincidence detectors that encode interaural time differences. The entire circuit, from the auditory nerve to the nucleus magnocellularis to the nucleus laminaris, is specialized for the encoding and preservation of temporal information. A mathematical model of this circuit provides useful predictions.

Interaural time difference (ITD), or the difference in timing of a sound wave arriving at the two ears, is a fundamental cue for sound localization. A wide variety of animals have specialized neural circuits dedicated to the computation of ITDs. In the avian auditory brainstem, ITDs are encoded as the spike rates in the coincidence detector neurons of the nucleus laminaris (NL). NL neurons compare the binaural phase-locked inputs from the axons of ipsi-and contralateral nucleus magnocellularis (NM) neurons. Intracellular recordings from the barn owl's NL in vivo showed that tonal stimuli induce oscillations in the membrane potential. Since this oscillatory potential resembled the stimulus sound waveform, it was named the sound analog potential . Previous modeling studies suggested that a convergence of phase-locked spikes from NM leads to an oscillatory membrane potential in NL, but how presynaptic, synaptic, and postsynaptic factors affect the formation of the sound analog potential remains to be investigated. In the accompanying paper, we derive analytical relations between these parameters and the signal and noise components of the oscillation. In this paper, we focus on the effects of the number of presynaptic NM fibers, the mean firing rate of these fibers, their average degree of phase-locking, and the synaptic time scale. Theoretical analyses and numerical simulations show that, provided the total synaptic input is kept constant, changes in the number and spike rate of NM fibers alter the ITD-independent noise whereas the degree of phase-locking is linearly converted to the ITD-dependent signal component of the sound analog potential. The synaptic time constant affects the signal more prominently than the noise, making faster synaptic input more suitable for effective ITD computation.

A biologically detailed model of the binaural avian nucleus laminaris is constructed, as a twodimensional array of multicompartment, conductance-based neurons, along tonotopic and interaural time delay (ITD) axes. The model is based primarily on data from chick nucleus laminaris. Typical chick-like parameters perform ITD discrimination up to 2 kHz, and enhancements for barn owl perform ITD discrimination up to 6 kHz. The dendritic length gradient of NL is explained concisely. The response to binaural out-of-phase input is suppressed well below the response to monaural input (without any spontaneous activity on the opposite side), implicating active potassium channels as crucial to good ITD discrimination.

Animals, including humans, use interaural time differences (ITDs) that arise from different sound path lengths to the two ears as a cue of horizontal sound source location. The nature of the neural code for ITD is still controversial. Current models differentiate between two population codes: either a map-like rate-place code of ITD along an array of neurons, consistent with a large body of data in the barn owl, or a population rate code, consistent with data from small mammals. Recently, it was proposed that these different codes reflect optimal coding strategies that depend on head size and sound frequency. The chicken makes an excellent test case of this proposal because its physical pre-requisites are similar to small mammals, yet it shares a more recent common ancestry with the owl. We show here that, like in the barn owl, the brainstem nucleus laminaris in mature chickens displayed the major features of a place code of ITD. ITD was topographically represented in the maximal responses of neurons along each isofrequency band, covering approximately the contralateral acoustic hemisphere. Furthermore, the represented ITD range appeared to change with frequency, consistent with a pressure gradient receiver mechanism in the avian middle ear. At very low frequencies, below400 Hz, maximal neural responses were symmetrically distributed around zero ITD and it remained unclear whether there was a topographic representation. These findings do not agree with the above predictions for optimal coding and thus revive the discussion as to what determines the neural coding strategies for ITDs.

In birds and mammals, precisely timed spikes encode the timing of acoustic stimuli, and interaural acoustic disparities propagate to binaural processing centers. The Jeffress model proposes that these projections act as delay lines to innervate an array of coincidence detectors, every element of which has a different relative delay between its ipsilateral and contralateral excitatory inputs. Thus, interaural time difference (ITD) is encoded into the position of the coincidence detector whose delay lines best cancel out the acoustic ITD. Neurons of the avian nucleus laminaris and mammalian MSO phase-lock to both monaural and binaural stimuli but respond maximally when phase-locked spikes from each side arrive simultaneously, i.e. when the difference in the conduction delays compensates for the ITD. McAlpine et al. [Nat. Neurosci. 4 (2001) 396] identified an apparent difference between avian and mammalian ITD coding. In the barn owl, the maximum firing rate appears to encode ITD. This may not be the case for the guinea pig, where the steepest region of the function relating discharge rate to interaural time delay (ITD) is close to midline for all neurons, irrespective of best frequency (BF). These data suggest that low BF ITD sensitivity in the guinea pig is mediated by detection of a change in slope of the ITD function, and not by maximum rate. We review coding of low best frequency ITDs in barn owls and mammals and discuss whether there may be differences in the code used to signal ITD in mammals and birds.

Owls are specialized predators and have very large eyes, which allow vision in limited light, and an acute hearing. These characteristics make them well adapted for hunting at night (VENABLE 1997). Although small mammals are the main food source of Barn owls, they also prey on other vertebrates and insects (e.g.,

The deposition of anticoagulant residues in the eggs of barn owls, Tyto alba by assessing eggshell thickness were investigated in oil palm plantations. Three study plots were set aside; one plot each baited with chlorophacinone and bromadiolone, respectively and the third was left unbaited. Four baiting campaigns were conducted on the rodenticide designated plots, coinciding with the breeding seasons of T. alba. High performance liquid chromatography (HPLC) showed that 29.73% (n=37) and 5.35% (n=56) of addled eggs collected from rodenticide treated plots contained bromadiolone and chlorophacinone, respectively, with mean concentration of residues from 0.009 to 0.031 µg/g wet weight. None of the addled eggs (n=28) collected from the unbaited plot contained bromadiolone or chlorophacinone residues. The detection of rodenticide residues in both albumen and yolk indicated high risk of secondary poisoning to both compounds. However, low levels of residues detected have no effects on shape of egg, eggshell mass or thickness.

The barn owl (Tyto alba) belongs to the order Strigiformes and family Tytonidae (Scopoli) inhabits all the continents, except that of Antarctica, among the grasslands, ruins in the agricultural fields, old and tall trees and pastures (Konig & Weick, 2008). It is mainly cosmopolitan and as such, occurs in fairly good proportions among the agricultural stations and feeding lots, preying on small mammals, insects, few small reptiles and birds (Sibley & Monroe, 1990; Taylor, 1994; Tores et al. 2005). Analysis of owl pellets has long been used for the detection of small mammals, birds and insects (Massoia, 1983; Torre et al. 2004). As an efficient and potential biological predator, its importance to feed on a wide variety of small mammals (as major vertebrate pests) is economically important along with the conservation status (Cayford, 1992). ISSN: 2319-7706 Volume 3 Number 8 (2014) pp. 211-218 http://www.ijcmas.com

The marine avifauna of Matthew and Hunter Islands, two remote volcanoes of the New Hebrides chain. Breeding birds recorded on Matthew and Hunter Islands in the tropical southwestern Pacific between 1973 and 2018 are summarised from a compilation of reports, for which various methods were used for counting seabirds. These methods included line transects, or direct observations using telescope or binoculars, or exhaustive counts, depending on the species observed and its nesting habitat. Population size estimates and reproductive periods are given. The total number of seabird species recorded breeding on the two islands was n = 14. This total includes seabird species breeding on both islands (n = 7): black-winged petrel Pterodroma nigripennis, wedge-tailed shearwater Ardenna pacifica, red-tailed tropicbird Phaethon rubricauda, masked booby Sula dactylatra, brown booby S. leucogaster, brown noddy Anous stolidus, and grey noddy A. albivitta. Hunter island also harbours a small colony of Herald petrel Pterodroma heraldica, and colonies of lesser and great frigatebirds (Fregata ariel and F. minor), red-footed booby S. sula and, black noddy A. minutus and white tern Gygis alba. Matthew Island harbours a large colony of sooty tern Onychoprion fuscatus; an undetermined storm petrel may also breed there. Differences between the two islands regarding community composition of seabirds are explained by the absence of trees on Matthew Island and the presence of the Polynesian rat Rattus exulans on Hunter Island. Brown noddies bred exclusively during the austral summer, as did black-winged petrels and wedge-tailed shearwaters, while the Herald petrel and the two frigatebirds seemed to preferentially breed in the winter. The red-tailed tropicbird, the three boobies, the grey noddy and the sooty tern appeared to reproduce year-round. Disturbance caused by human activities was irregular but devastating to seabird colonies. The diversity and abundance of seabird species breeding on these islands makes them regionally important sites for conservation.

Raptor-prey encounters were studied to evaluate the strategies and success rate of both predator attack and prey defense. We compared the success of barn owls in catching stationary simulated prey (food item) with that of moving prey (food item that was pulled in various directions). We also tracked real encounters between barn owls and spiny mice in a captive environment. It was found that owls had higher success in attacking stationary prey and that they seemed to attack the prey as soon as it became motionless. When attacked, only a few spiny mice remained immobile (freeze response) whereas most fled and usually avoided capture by the owls. It was also found that spiny mice displayed a preference to escape in those directions in which owls had demonstrated a lower success in catching the simulated prey. Escape initiation dichotomized to a short or long (but rarely intermediate) distance between the spiny mouse and the owl with more successful avoidance at short-distance (last-moment) escapes. The best predictor of escape success was the velocity of the spiny mouse, and the second best predictor was its flight initiation distance (FID). We present an update for Ydenberg and Dill's model for optimal FID in close encounters, suggesting that fleeing at the last moment is advantageous. However, a last-moment attempt to escape is also more risky with a split second differing between life and death, and is therefore appropriate mainly for agile prey under close-distance attack.

The dominant food-items eaten by the short-eared owl were rats and mice (91.9%). Shrews (2.0%), bats (1.3%), and birds (5.0%) jointly constituted only 8.2% of the owl's diet. Among rats and mice, the most intensively consumed rodent pest by the owl was Millardia meltada (43.9%), followed by Mus musculus (29.8%), Tatera indica (16.3%), and Bandicota bengalensis (1.8%). In the case of the barn owl, rats and mice represented 9.7% of their diet, followed by shrews (4.7%), birds (3.3%), and bats (0.4%). Among the rats and mice in their diet were M. meltada (46.3%), T. indica (3.5%), Nesokia indica (5.1%), B. bengalensis (2.2%), Rattus rattus (1.1%), and M. musculus (33.5%). Sub-adults of M. meltada were the most intensively eaten food item by the short-eared owl (50.8%) and barn owl (39.1%), whereas adults of M. musculus were the dominant prey agecategory consumed by the short-eared owl (52.2%) and barn owl (66.0%).

Homologous recombination is a meiotic process that generates diversity along the genome and interacts with all evolutionary forces. Despite its importance, studies of recombination landscapes are lacking due to methodological limitations and a dearth of appropriate data. Linkage mapping based on familial data gives unbiased sex-specific broad-scale estimates of recombination while linkage disequilibrium (LD) based inference based on population data provides finer resolution data albeit depending on the effective population size and acting selective forces. In this study, we use a combination of these two methods, using a dataset of whole genome sequences and elucidate the recombination landscape for the Afro-European barn owl (Tyto alba). Linkage mapping allows us to refine the genome assembly to a chromosome-level quality. We find subtle differences in crossover placement between sexes that leads to differential effective shuffling of alleles. LD based estimates of recombination are concordant with family-based estimates and identify large variation in recombination rates within and among linkage groups. Larger chromosomes show variation in recombination rates while smaller chromosomes have a universally high rate which shapes the diversity landscape. We also identify local recombination hotspots in accordance with other studies in birds lacking the PRDM9 gene. However these hotspots show very little evolutionary stability when compared among populations with shallow genetic differentiation. Overall, this comprehensive analysis enhances our understanding of recombination dynamics, genomic architecture, and sex-specific variation in the barn owl, contributing valuable insights to the broader field of avian genomics. .

In this study, a novel parvovirus (strain swine/ Zsana3/2013/HUN, KT965075) was detected in domestic pigs and genetically characterized by viral metagenomics and PCR methods. The novel parvovirus was distantly related to the human bufaviruses and was detected in 19 (90.5 %) of the 21 and five (33.3 %) of the 15 faecal samples collected from animals with and without cases of posterior paraplegia of unknown etiology from five affected farms and one control farm in Hungary, respectively. Swine/Zsana3/2013/HUN is highly prevalent in domestic pigs and potentially represents a novel parvovirus species in the subfamily Parvovirinae.

Rooikrans Acacia cyclops is an invasive plant species in the coastal region of South Africa, especially the Fynbos Biome. It is endemic to southwestern Australia. Seeds are bird‐dispersed, mostly by frugivores and granivores. We report that at one locality in South Africa, Barn Swallows Hirundo rustica, normally regarded as obligate foragers of aerial arthropods, also consumed the seeds and associated arils of Rooikrans shrubs and trees. The seeds were voided and the arils digested. Three thousand Barn Swallows in the region where this was observed conceivably consumed and voided two million Rooikrans seeds during the 5‐month non‐breeding period. Barn Swallows are therefore dispersers of Rooikrans seeds. Many of the bird species known to consume Rooikrans seeds are territorial, so that seeds are not dispersed far beyond existing acacia stands. Barn Swallows cover large distances between feeding areas and roosts, and could therefore disperse seeds far from existing stands. This devel...

Even though birds are some of the most common road-killed animals, it remains to be determined whether avian roadkills are related to breeding numbers and breeding success, mainly due to a lack of study areas that monitor breeding populations and roadkills. We studied whether barn owl breeding numbers and breeding success are related to roadkills. We monitored yearly barn owl breeding numbers (2174 breeding attempts and 1682 adults ringed) and breeding success (9380 nestlings ringed) and monitored 95 km of roads weekly for roadkills from 2009 to 2017 in the Beit Shean and Emek Yizreel Valleys, Israel. During the study period, we documented 1073 road-killed barn owls, of which 328 were ring recoveries. The highest mortality occurred between July to September, coinciding with the barn owl post-fledging period. The number of breeding pairs and the number of nestlings ringed were positively related to the total number of barn owl roadkill, the proportion of roadkill ring recoveries, and...

The normal numbers of micronucleated erythrocytes MNE observed in peripheral blood samples differ among species. Ž. This depends on the effectiveness of the spleen or the rest of the reticuloendothelial system to withdraw them from circulation. In our previous report, we assessed the number of MNE in the peripheral blood of 35 mammalian species. Here we show the results observed in 54 species including mammals, reptiles and birds. We obtained 212 peripheral blood samples from different species. In 14 species, only one individual was studied. Slides were stained with acridine orange. The Ž. total number of MNE normo and polychromatic in 10,000 erythrocytes per animal are shown. The species that display the higher MNE were: ocelote, lynx, owl, gray squirrel, hedgehog, lion, orange fronted parakeet and common barn owl. For this reason, these species could be tested as monitors for genotoxic events. Another interesting observation was that in the gray squirrel, we found the highest values of MNE in the smaller Ž. Ž. younger animals when compared with the larger older of the same species.

Islands, and the particular organisms that populate them, have long fascinated biologists. Due to their isolation, islands offer unique opportunities to study the effect of neutral and adaptive mechanisms in determining genomic and phenotypical divergence. In the Canary Islands, an archipelago rich in endemics, the barn owl (Tyto alba) is thought to have diverged into a subspecies (T. a. gracilirostris) on the eastern islands, Fuerteventura and Lanzarote. Taking advantage of 40 whole-genomes and modern population genomics tools, we provide the first look at the origin and genetic makeup of barn owls of this archipelago. We show that the Canaries hold diverse, long-standing and monophyletic populations with a neat distinction of gene pools from the different islands. Using new method, less sensitive to structure than classicalFST, to detect regions involved in local adaptation to the insular environment, we identified a haplotype-like region likely under positive selection in all Can...

The normal numbers of micronucleated erythrocytes MNE observed in peripheral blood samples differ among species. Ž. This depends on the effectiveness of the spleen or the rest of the reticuloendothelial system to withdraw them from circulation. In our previous report, we assessed the number of MNE in the peripheral blood of 35 mammalian species. Here we show the results observed in 54 species including mammals, reptiles and birds. We obtained 212 peripheral blood samples from different species. In 14 species, only one individual was studied. Slides were stained with acridine orange. The Ž. total number of MNE normo and polychromatic in 10,000 erythrocytes per animal are shown. The species that display the higher MNE were: ocelote, lynx, owl, gray squirrel, hedgehog, lion, orange fronted parakeet and common barn owl. For this reason, these species could be tested as monitors for genotoxic events. Another interesting observation was that in the gray squirrel, we found the highest values of MNE in the smaller Ž. Ž. younger animals when compared with the larger older of the same species.

Science for Conservation is a scientific monograph series presenting research funded by New Zealand Department of Conservation (DOC). Manuscripts are internally and externally peer-reviewed; resulting publications are considered part of the formal international scientific literature. This report is available from the departmental website in pdf form. Titles are listed in our catalogue on the website, refer www.doc.govt.nz under Publications, then Science & technical.

Since the pioneering work performed by Honigmann (1911)l who investigated the effects of moving textured background on the prey-catching behavior in the toad, it has been known that the toad can (I) extract "prey-object" from "background" if the object moves against the stationary background, and (2) discriminate between "real" and "self-induced" object motion if the background is textured. This implies that (1) local visual motion through restricted part of the visual field is essential for eliciting prey-catching behavior in the toad, and (2) global visual motion through large part of it suppresses this behavior. These considerations led us to a question as to neural mechanism underlying the prey-catching behavior: are there "local motion detectors" in the toad's central nervous system that arc not activated by global motion extending large part of the visual field, but are activated by local motion restricted within small part of it? From experiments using a perimeter apparatus designed for testing this specific question z-s, here, I report that many neurons in the optic tectum of the Japanese toad well fit ~'Ath such a category of "local motion detectors" as defined above. Majority of the tectal class 'i"7, T5 and T4 neurons ",'.'ere not activated by global motion of the visual noise pattern, but were activated both by small object (8"x8" black square, or 8* xS* visual noise pattern) moving against the stationary background textured with visual noise pattern and by local motion of the visual noise pattern. A part of the tectal neurons were activated by all of these three types of visual motion: the small moving object, local and global motion of the visual noise pattern. On the other hand. no tectal neurons were found that were not activated by the small moving object or by local motion of the visual noise pattern, hut were activated by global motion of the visual noise pattern. Moreover. in most cases, the responses of tectal neurons to the small moving object were suppressed, if the textured background moved in-phase as well as anti-phage with the object. It was revealed that these properties of the tectal neurons as the "local motion detectors" can he explained in terms of their antagonistic receptive field organization; the excitatory center is encircled by inhibitory surround. and the excitatory center become~ inhibitory if larger part of it is stimulated. These findings suggest that local motion prOCessing in th~ optic rectum pla)s a principal role in elieJting the prey-catching behavior ~f anurans. Data as ~c, the elcctromyographic activity during the prey-caiching, be/~avior ~,~ as v.'e~ as the ne~r~nal pathways item the ootic rectum to mater areas relevant to the prey-catching behavior ~. ~ were also orescr~ted. 'ttonigmann H (l~ ltl Pro¢ R See l.dttd 132: 291; ~'l?~,ai H-jet al (I989) r'~at~rwias 76: 37; nSatou hi et al (1989) Brain Res 501: 320; ' Matsuahima T et al (L985) Neurosci [t¢~ 3:L5 l; ' Take~chi H-A et al (zubmitted); 6 Satou Met al (1985) J Comp Physiol A L51: 7t7: 7 Matsushima Tel al (t989) J Comp P~slol A t66:7.

Molecular sexing of Tyto alba javanica Abstrak. Penentuan jantina burung adalah penting untuk tujuan kajian ekologi dan biologi evolusi, serta program pembiakan dan konservasi terutamanya bagi burung yang mempunyai ciri monomorfik. Bagi burung pungguk jelapang Tyto alba pengesahan jantina adalah penting untuk konservasi serta program pengenalan bagi kawalan tikus perosak. Penentuan jantina secara molekular untuk subspecies Asia Tenggara, Tyto alba javanica, telah dijalankan menggunakan PCR diikuti 3% gel agaros elektroforesis. Primer P2/P8 and 2550F/2718R untuk amplifikasi gen CHD (Chromo Helicase DNA-binding gene) diuji dan kedua-dua set primer memberi keputusan yang berjaya. Set primer 2550F/2718R memberi hasil yang lebih baik kerana jurang di antara jalur berganda lebih terang. DNA yang diekstrak dari darah, darah yang dicairkan, serta DNA yang diekstrak dari bulu burung diguna untuk menentukan jantina burung. DNA yang diekstrak dari bulu memberi keputusan yang kurang memuaskan akibat pencemaran serta kuantiti DNA yang rendah. Penentuan jantina menggunakan darah yang dicairkan merupakan kaedah yang menjimatkan kos serta masa. Penjujukan gen CHD dari Tyto alba javanica menunjukkan 98% hingga 99% kesamaan identiti bila dibandingkan gen CHD Tyto alba alba.

We have identified 15 polymorphic microsatellite loci for the barn owl (Tyto alba), five from testing published owl loci and 10 from testing non‐owl loci, including loci known to be of high utility in passerines and shorebirds. All 15 loci were sequenced in barn owl, and new primer sets were designed for eight loci. The 15 polymorphic loci displayed two to 26 alleles in 56–58 barn owls. When tested in 10 other owl species (n = 1–6 individuals), between four and nine loci were polymorphic per species. These loci are suitable for studies of population structure and parentage in owls.

A clinical study was conducted on the intermittent hydronephrosis in children. Of 78 children with hydronephrosis due to ureteropelvic junction obstruction operated between 1991 and 1995, 5 had intermittent hydronephrosis. All 5 patients were boys between 6 months and 6 years of age. Presenting symptoms were intermittent flank pain and vomiting. Ultrasonography performed during pain attack demonstrated dilation of the renal pelvis in all patients. Diuretic renography demonstrated obstruction in 4 of the 5 children and deterioration of renal function on the affected side in 2. The cause of ureteropelvic junction obstruction was aberrant vessels in 2 cases, fibrous band in 1, ureteral kinking within adventitia in 1 and a ureteral polyp in 1. Postoperatively, all patients have been relieved from the pain. In summary, ultrasonography at the time of symptom attack as well as diuretic renography are useful for the diagnosis and observation of intermittent hydronephrosis.

 Rodents run frantically in response to a taking off barn owl after its attack  We recorded the sounds generated by an owl in landing on and taking off from a prey  Takeoff sounds were significantly louder than those of swooping-down  Both landing and takeoff noise seem to be below the rodents' hearing threshold  The rodents' response may be tactile reception of air-puffs of the owl's wingbeats ABSTRACT A barn owl swooping down generated a quieter, almost silent, noise (acoustic impulses) compared to a louder noise generated by the owl when taking off. These acoustic impulses are at low frequencies which are below the auditory threshold to most rodents. Therefore, rodents are less likely to hear these noises of owl flight. A previous study revealed that rodents exhibit frantic response to an owl taking off (as opposed to their typical freezing response during owl attack). The frantic response could be the result of tactile reception of the air-puffs generated by the owl's wingbeats and may reduce the success in subsequent attacks.