| 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 |
| a species of sarcocystis using owls as definitive hosts. | sporulated oocysts found in the intestines of a masked owl (tyto novaehollandiae) and a barn owl (t. alba) produced sarcocysts in mice. schizonts were found in the livers of 3 mice that died at 7-8 days after dosing. neither sarcocysts nor schizonts were found in chickens dosed with oocysts from a masked owl. | 1977 | 405512 |
| experiments on direct and secondary poisoning by fluoroacetamide (1081) in wildlife and domestic carnivores. | fluoroacetamide (1081 or f.a.a) is used in israel for field rodent control. experiments on direct and secondary, short and long term poisoning caused by 1081 were carried out. mongoose (herpestes ichneumon), hyena (hyaena hyaena), cats and dogs were susceptible. barn owls (tyto alba), buzzards (buteo buteo) and black kites (milvus m. migrans) were markedly resistant. barn owls tolerated total direct poisoning ranging from 6.8 to 10.9, and a final dose ranging from 0.8 to 2.0 mg/kg. in secondary ... | 1979 | 480523 |
| relationship of oocysts of "isospora duteonis" from the barn-owl (tyto alba) to muscle cysts of sarcosporidians from the house mouse (mus musculus). | | 1976 | 827479 |
| neurons selective for orientation and binocular disparity in the visual wulst of the barn owl (tyto alba). | the visual response properties of single neurons in the owl's visual wulst suggest that this forebrain structure is an analog of the mammalian visual cortex. features in common with the cat and the monkey visual cortex include a precise topographic organization, a high degree of binocular interaction, and selectivity for orientation, direction of movement, and binocular disparity of straight-line contours. | 1976 | 948741 |
| cytochrome p-450 mediated metabolism of progesterone by adrenal microsomes of pcb-treated and untreated barn owl (tyto alba) and marsh turtle (mauremys caspica) in comparison with the guinea-pig. | 1. significant differences between species were observed in the profile of steroids produced from progesterone by adrenal microsomes as well as in the effects elicited by aroclor 1254 on cytochrome p-450-mediated activities. 2. in the guinea-pig, the major metabolites were products of the corticosteroid pathway but products of the androgenic pathway were also detected; in the barn owl products of both pathways were also formed while in the marsh turtle only products of the corticosteroid pathway ... | 1991 | 1675970 |
| neural coding in the chick cochlear nucleus. | physiological recordings were made from single units in the two divisions of the chick cochlear nucleus-nucleus angularis (na) and nucleus magnocellularis (nm). sound evoked responses were obtained in an effort to quantify functional differences between the two nuclei. in particular, it was of interest to determine if nucleus angularis and magnocellularis code for separate features of sound stimuli, such as temporal and intensity information. the principal findings are: 1. spontaneous activity p ... | 1990 | 2341992 |
| toxoplasma gondii antibodies in common barn-owls (tyto alba) and pigeons (columba livia) in new jersey. | in southwestern new jersey during 1986 and 1987, common barn-owls and pigeons were captured on farmsteads and tested for toxoplasma gondii antibodies by a modified direct agglutination test. in 1986, 3/28 (10.7%) adult and 0/124 nestling owls tested positive at titers of greater than or equal to 1:40. additionally, 2/34 (5.9%) pigeons tested had t. gondii antibodies at titer of 1:320. in 1987, 9/38 (27.3%) adult and 18/80 (22.5%) nestling owls tested positive at titers of greater than or equal t ... | 1990 | 2382386 |
| experimental oral inoculations in birds to evaluate potential definitive hosts of neospora caninum. | experimental oral inoculations to evaluate potential definitive hosts of neospora caninum were conducted by feeding infected rodent tissues to 9 carnivorous birds of 4 species. birds included 2 red-tailed hawks (buteo jamaicensis), 2 turkey vultures (cathartes aura), 2 barn owls (tyto alba), and 3 american crows (corvus brachyrhynchus). the rodents (mice or rats) had been inoculated with 100,000 culture-derived tachyzoites of n. caninum 1-6 mo before feeding to the birds. fecal samples were coll ... | 1995 | 7472875 |
| binaural cross-correlation predicts the responses of neurons in the owl's auditory space map under conditions simulating summing localization. | summing localization describes the perceptions of human listeners to two identical sounds from different locations presented with delays of 0-1 msec. usually a single source is perceived to be located between the two actual source locations, biased toward the earlier source. we studied neuronal responses within the space map of the barn owl to sounds presented with this same paradigm. the owl's primary cue for localization along the azimuth, interaural time difference (itd), is based on a cross- ... | 1996 | 8753891 |
| molecules and cognition: the latterday lessons of levels, language, and lac. evolutionary overview of brain structure and function in some vertebrates and invertebrates. | the characteristics of the nervous systems of a number of organisms in different phyla are examined at the recombinant dna, protein, neuroanatomic, neurophysiological, and cognitive levels. among the invertebrates, special attention is paid to the advantages as well as the shortcomings of the fly drosophila melanogaster, the worm caenorhabditis elegans, the honey bee apis mellifera, the sea hare aplysia californica, the octopus octopus vulgaris, and the squid loligo pealei. among vertebrates, th ... | 1993 | 8331341 |
| an axon with a myelinated initial segment in the bird auditory system. | in the bird auditory brainstem, nucleus laminaris neurons compute interaural time differences by comparing inputs from two ears. laminaris neurons in barn owls have short dendrites and axons with myelinated initial segments. we examined laminaris cells in chickens with a range of dendritic lengths to determine if neurons with long dendrites had normal axons. neurons with short dendrites had myelinated initial segments while neurons with long dendrites had normal initial segments. thus, the myeli ... | 1993 | 8313166 |
| prevalence of encysted toxoplasma gondii in raptors from alabama. | little is known about the prevalence of encysted toxoplasma gondii in wild birds. we examined the hearts and breast muscles from 101 raptors for encysted t. gondii. all of the raptors had been submitted for necropsy to the state veterinary diagnostic laboratory, auburn, alabama. tissues were digested in acid-pepsin solution and inoculated into groups of 3-5 laboratory mice. toxoplasma gondii was isolated from 27 of 101 (26.7%) raptors: 8 of 12 (66.7%) red-shouldered hawks (buteo lineatus), 13 of ... | 1993 | 8277379 |
| tawny owl (strix aluco) and hume's tawny owl (strix butleri) are distinct species: evidence from nucleotide sequences of the cytochrome b gene. | the cytochrome b gene of the tawny owl (strix aluco), hume's tawny owl (strix butleri) and the african wood owl (strix woodfordii) was amplified by polymerase chain reaction (pcr) and partially sequenced (300 base pairs). sequences differ substantially (9 to 12% nucleotide substitutions) between these taxa indicating that they represent distinct species, which is also implicated from morphological and biogeographic differences. using cytochrome b sequences of s. aluco, s. butleri, s. woodfordii, ... | 1994 | 8018253 |
| general pattern and morphological specializations of the avian cochlea. | in different bird species, there is a common pattern in the hair-cell morphology and innervation of the basilar papilla; the absolute values, however, are species-specific. in the barn-owl papilla, an extreme being case, the basal high-frequency part of the papilla is greatly expanded. in this behaviorally most important frequency range of the barn owl, the number of afferent nerve terminals to neural hair cells is extensively increased. instead of about 2 afferent terminals as in other species, ... | 1994 | 7701304 |
| binaural tuning of auditory units in the forebrain archistriatal gaze fields of the barn owl: local organization but no space map. | we identified a region in the archistriatum of the barn owl forebrain that contains neurons sensitive to auditory stimuli. nearly all of these neurons are tuned for binaural localization cues. the archistriatum is known to be the primary source of motor-related output from the avian forebrain and, in barn owls, contributes to the control of gaze, much like the frontal eye fields in monkeys. the auditory region is located in the medial portion of the archistriatum, at the level of the anterior co ... | 1995 | 7623142 |
| raptors lack lower-field myopia. | the presence of lower-field myopia (described in chickens, pigeons, quail and amphibians) allows these animals to keep the ground in focus while performing other visual tasks. a relationship has also been reported between the eye height and the degree of myopia observed. all of the animals reported in the literature to date are ground-foraging species. using infrared neutralizing video retinoscopy and static photoretinoscopy we found a lower-field myopia to be absent in the barn owl (tyto alba), ... | 1995 | 7610576 |
| head-related transfer functions of the barn owl: measurement and neural responses. | sounds arriving at the eardrum are filtered by the external ear and associated structures in a frequency and direction specific manner. when convolved with the appropriate filters and presented to human listeners through headphones, broadband noises can be precisely localized to the corresponding position outside of the head (reviewed in blauert, 1997). such a 'virtual auditory space' can be a potentially powerful tool for neurophysiological and behavioral work in other species as well. we are d ... | 1998 | 9606058 |
| space-mapped auditory projections from the inferior colliculus to the optic tectum in the barn owl (tyto alba). | the optic tectum of the owl contains a topographic representation of auditory space. we have investigated the source of this space-mapped auditory activity by using retrograde tracing with horseradish peroxidase. the major source of auditory input to the optic tectum is the ipsilateral external nucleus of the inferior colliculus (icx), which is known to contain a map of auditory space also. additional minor projections originate in the superficial nucleus of the inferior colliculus and the nucle ... | 1983 | 6886071 |
| radiographic monitoring of the ossification of long bones in kori (ardeotis kori) and white-bellied (eupodotis senegalensis) bustards. | a serial radiographic study was conducted on eight kori bustard (ardeotis kori) and four white-bellied bustard (eupodotis senegalensis) chicks to determine the pattern of long bone development and to establish radiographic standards for assessing skeletal maturity. the ossification pattern, appearance of secondary ossification centres, and epiphyseal fusion of the long bones in kori and white-bellied bustards were similar to those in houbara bustards (chlamydotis undulata macqueenii), rufous-cre ... | 1998 | 9839896 |
| the role of birds as definitive hosts and intermediate hosts of heteroxenous coccidians. | sarcocystis-like oocysts-sporocysts were found in four species of owls (asio otus, bubo bubo, strix aluco, and tyto alba) and in five species of predatory birds (accipiter gentilis, accipiter nisus, buteo buteo, circus aeruginosus, falco tinnunculus). in addition, the muscles of 15 of 41 (36.5%) pheasants (phasianus colchicus) and one of two jays (garrulus glandarius) were found to harbor three types of sarcocystis. three of 15 (20%) infected pheasants had type i cystozoites (6-8 x 2 microns) in ... | 1984 | 6439858 |
| experience alters the spatial tuning of auditory units in the optic tectum during a sensitive period in the barn owl. | the auditory spatial tuning of bimodal (auditory-visual) units in the optic tectum of the barn owl was altered by raising animals with one ear occluded. changes in spatial tuning were assessed by comparing the location of a unit's auditory best area with that of its visual receptive field. as shown previously, auditory best areas are aligned with visual receptive fields in the tecta of normal birds (knudsen, e. i. (1982) j. neurosci. 2: 1177-1194). it was demonstrated in this study that, when bi ... | 1985 | 4056865 |
| nuclear origin of the centrifugal visual pathway in birds of prey. | the isthmo-optic nucleus (nio) at the origin of the retinopetal pathway was examined in 12 birds of prey (strigiforms and falconiforms) using cytoarchitectonic methods and after the intraocular injection of the regrograde tracers rhodamine beta-isothiocyanate and fast blue. the nio was found to be poorly differentiated and reticular in appearance and depending on the species contained between 900 and 1400 neurons. these values are approximately 10 times less than those recorded in the pigeon and ... | 1987 | 3690347 |
| salmonella spp. in nestling common barn-owls (tyto alba) from southwestern new jersey. | the prevalence of salmonella spp. in nestling common barn-owls was investigated in southwestern new jersey during the summer of 1985. of 94 owls sampled by swabbing the cloaca, eight (8.5%) were found to harbor salmonella spp. three serotypes--s. thompson, s. tuindorp, and s. typhimurium--were identified. five (20%) of the 25 nest sites examined (all of them in or near farm buildings or dwellings) contained salmonella-positive owls. | 1986 | 3525874 |
| translation of sensory signals into commands for control of saccadic eye movements: role of primate superior colliculus. | afferent signals that guide orienting movements converge in the deeper layers of the sc in a wide variety of animals. the sensory cells are arranged topographically according to their receptive-field locations and, thereby, form maps of sensory space. maps of visual, somatosensory, and/or auditory space have been obtained in the iguana, mouse, hamster, barn owl, chinchilla, cat, and monkey. the deeper layers of the sc also contain neurons involved in the generation of movements of the eyes, head ... | 1986 | 3511480 |
| mouse (mus musculus) as intermediate host of sarcocystis sp. from the goshawk (accipiter gentilis). | sporocysts from the goshawk (accipiter gentilis) were experimentally transferred to the mouse (mus musculus). it was found that the goshawk is the host of one of the sarcosporidians inducing muscle sarcocystosis in mice. thin-walled, sporulated oocysts expelled by the goshawk measured 16.5-19.0 x 12.0-13.0 micron. those which measured 12.0-13.5 x 8.2-9.0 micron were widely elliptical, with rounded poles. no asexual reproduction of parasites was detected in the viscera of mice. the cysts started ... | 1986 | 3084365 |
| quantitative analysis of the retinal ganglion cell layer and optic nerve of the barn owl tyto alba. | the visual capacity of the common barn owl (tyto alba) was studied by quantitative analysis of the retina and optic nerve. cell counts in the ganglion cell layer of the whole-mounted retina revealed a temporal area centralis with peak cell density of 12,500 cells/mm2 and a horizontal streak of high cell density extending from the area centralis into the nasal retina. integration of the ganglion cell density map gave an estimated total of 1.4 million cells for the ganglion cell layer. electron mi ... | 1989 | 2758316 |
| a quantitative study of cochlear afferent axons in birds. | this paper is a comparative study of auditory-nerve morphology in birds. the chicken (gallus gallus), the emu (dromaius novaehollandiae) and the starling (sturnus vulgaris) were chosen as unspecialised birds that have already been used in auditory research. the data are discussed in comparison to a similar earlier study on the barn owl, a bird with highly specialised hearing, in an attempt to separate general avian patterns from species specialisations. average numbers of afferent fibres from 87 ... | 2000 | 10601718 |
| neural maps of head movement vector and speed in the optic tectum of the barn owl. | 1. this study investigates the contribution of the optic tectum in encoding the metric and kinetic properties of saccadic head movements. we describe the dependence of head movement components (size, direction, and speed) on parameters of focal electrical stimulation of the barn owl's optic tectum. the results demonstrate that both the site and the amount of activity can influence head saccade metrics and kinetics. 2. electrical stimulation of the owl's optic tectum elicited rapid head movements ... | 1990 | 2299378 |
| exposure to the calls of predators of mice activates defensive mechanisms and inhibits consummatory behaviour in an inbred mouse strain. | as two-minute exposures to the tape-recorded calls of barn and tawny owls activate endogenous opioid-mediated analgesia mechanisms in laboratory mice, the behavioural effects of the calls of a variety of predator and nonpredator species were ethologically assessed. while no clear effect could be seen on cage-orientated behaviour, the calls of the barn owl and tawny owl produced consistent increases in self-orientated, call-orientated and defensive behaviour indicating that these calls were recog ... | 1991 | 1792009 |
| a temporal window for lateralization of interaural time difference by barn owls. | lateralization of interaural time difference by barn owls (tyto alba) was studied in a dichotic masking experiment. sound bursts consisted of two parts: binaurally time-shifted noise, termed the probe, was inserted between masking noise. the owls indicated that they detected and lateralized the time-shift in the probe by a head turn in the direction predicted from sign of the time-shift. the general characteristics of head turns in response to this stimulus was similar to the head turns elicited ... | 1991 | 1762092 |
| response of auditory units in the barn owl's inferior colliculus to continuously varying interaural phase differences. | 1. we studied the response of single units in the central nucleus of the inferior colliculus (icc) of the barn owl (tyto alba) to continuously varying interaural phase differences (ipds) and static ipds. interaural phase was varied in two ways: continuously, by delivering tones to each ear that varied by a few hertz (binaural beat, fig. 1), and discretely, by delaying in fixed steps the phase of sound delivered to one ear relative to the other (static phase). static presentations were repeated a ... | 1992 | 1629755 |
| allometric relationships between embryonic heart rate and fresh egg mass in birds. | previously, we have measured daily changes (developmental patterns) in embryonic heart rate (fh) in altricial and semi-altricial (asa) birds (range of mean fresh egg mass approximately 1-20 g), semi-precocial seabirds (egg mass approximately 38-288 g) and precocial birds (egg mass approximately 6-1400 g). an allometric relationship between embryonic fh at 80 % of incubation duration (id) and fresh egg mass (m) has been derived for six species of precocial bird (fh at 80 % id=429m(-0.118)). in th ... | 2001 | 11104720 |
| the humeroscapular bone of the great horned owl (bubo virginianus) and other raptors. | a small, separate, bony density dorsal to the shoulder joint is radiographically visible in several species of large hawks and owls. gross dissection and histological examination show the bone to lie on the deep surface of the major deltoid muscle in intimate association with the dorsal coracohumeral ligament of the shoulder joint. the tendon of the supracoracoideus muscle passes immediately cranial to the humeroscapular bone. two ligaments distinct from the shoulder joint capsule attach the hum ... | 1992 | 1585989 |
| barn owls have symmetrical accommodation in both eyes, but independent pupillary responses to light. | we have studied accommodation behaviour in the barn owl (tyto alba). by defocussing one eye with various spectacle lenses and recording the refractive state in both eyes continuously during pecking, we found that the owls' accommodation was symmetrical in both eyes, with no regard to the power of the lens used. even with no visual input to one eye, the amount of accommodation was always identical in both eyes. on the other hand, pupillary responses to light were independent. this finding differs ... | 1992 | 1509706 |
| contribution to the problem of cyst-producing coccidians. | the problem of life cycles of cyst-producing coccidians, mainly those of the genus sarcocystis, from carnivorous birds has been discussed. oocysts of the "sarcocystic" type have been recovered from 9 species of birds of prey and owls from czechoslovakia. the course of experimental infection in a group of birds consisting of the species tyto alba, asio otus, strix aluco, buteo buteo has been described. we inoculated these birds with cystic stages of the genus sarcocystis obtained from white labor ... | 1978 | 416999 |
| pulmonary macrophages in birds (barn owl, tyto tyto alba), domestic fowl (gallus gallus f. domestica), quail (coturnix coturnix), and pigeons (columbia livia). | birds have a limited number of resident macrophages in the normal steady-state respiratory tract. the discovery of phagocytes in lavages of lung from birds contrasts with findings that phagocytes are seldom seen in investigations in situ. an electron microscopic study was performed in the respiratory units, the parabronchi, and air capillaries in particular in several adult bird species to localize the seat of respiratory macrophages. | 1996 | 8876827 |
| safety study of the sag2 rabies virus mutant in several non-target species with a view to its future use for the immunization of foxes in europe. | the safety of the sag2 virus, a low virulence mutant of the sad strain, was investigated in ten species of mammals and seven species of birds liable to consume vaccine baits. these species are the western hedgehog (erinaceus europaeus), the meadow vole (microtus arvalis), the bank vole (clethrionomys glareolus), the water vole (arvicola terrestris), the field mouse (apodemus flavicollis or a. sylvaticus), the norway rat (rattus norvegicus), the european badger (meles meles), the domestic ferret ... | 1996 | 9014291 |
| brain-derived neurotrophic factor/neurotrophin-4 receptor trkb is localized on ganglion cells and dopaminergic amacrine cells in the vertebrate retina. | the tyrosine kinase trkb is a receptor for the neurotrophic factors brain-derived neurotrophic factor (bdnf) and neurotrophin-4 (nt-4). retinal ganglion cells are responsive to bdnf, and trkb has been localized in ganglion cells as well as in a subpopulation of amacrine cells in the retina of the chicken and the rat. in the present paper, we analyzed the distribution of trkb immunoreactivity in the retina of marmoset monkeys, ferrets, rabbits, rats, mice, chickens, pigeons, barn owls, pseudemys ... | 1997 | 9303531 |
| an electron microscopic study of the parabronchial epithelium in the mature lung of four bird species. | no integrated comprehensive description of the ultrastructure of the parabronchial epithelium is available. the origin, discharge, and occurrence of the trilaminar substance have not yet been sufficiently studied. therefore, the main objectives were to classify the cell types of the parabronchial epithelium and to describe their role in manufacturing the trilaminar substance. | 1997 | 9335467 |
| [occurrence of parasites in indigenous birds of prey and owls]. | in the present paper a general overview on parasites in birds of prey and owls is given. this part is followed by a study investigating the prevalences and species of parasites in free-ranging birds of prey and owls in berlin and brandenburg state, germany. over a one year period, 84 birds of prey and owls of the following species were examined for the presence of endo- and ectoparasites: common buzzard (buteo buteo) (n = 32), kestrel (falco tinnunculus) (n = 20), sparrowhawk (accipiter nisus) ( ... | 2002 | 11852683 |
| anchoring and support system of pulmonary gas-exchange tissue in four bird species. | avian air capillaries are delicate structures compared to the mammalian pulmonary alveolus. a transmission and scanning electron microscopic study was carried out on several species of birds with the aim of determining the support structures of the avian gas-exchange mantle. lung tissue of two bird species belonging to strong flying birds (pigeon and barn owl) and two relatively flightless species (domestic fowl and quail) was subjected to standard processing for transmission and scanning electr ... | 1997 | 9522895 |
| how do owls localize interaurally phase-ambiguous signals? | owls and other animals, including humans, use the difference in arrival time of sounds between the ears to determine the direction of a sound source in the horizontal plane. when an interaural time difference (itd) is conveyed by a narrowband signal such as a tone, human beings may fail to derive the direction represented by that itd. this is because they cannot distinguish the true itd contained in the signal from its phase equivalents that are itd +/- nt, where t is the period of the stimulus ... | 1998 | 9600989 |
| stereoscopic depth perception in the owl. | it is unclear whether the neural algorithm that underlies stereoscopic vision in birds incorporates both low level (camouflage breaking) and high level (depth ordering) comparisons of information available to each of the eyes. both visual functions were successfully tested by examining transitive inference performance in two barn owls trained to discriminate static julesz random dot stereograms, thus demonstrating a capacity to detect relative depth using fine retinal disparity as the sole cue f ... | 1998 | 9601700 |
| newcastle disease virus and chlamydia psittaci in free-living raptors from eastern germany. | organ samples from free-living raptors from the federal states of berlin and brandenburg in eastern germany were tested for newcastle disease virus (ndv; n = 331) and chlamydia psittaci (n = 39) by polymerase chain reaction (pcr). in 18 individuals ndv nucleic acids were detected. these samples originated from barn owls (tyto alba; n = 15, 28%), tawny owl (strix aluco; n = 1, 5%), common buzzard (buteo buteo, n = 1, 1%), and european kestrel (falco tinnunculus; n = 1, 4%). in 29 (74%) of 39 samp ... | 2003 | 12685068 |
| hair cell morphology and innervation in the basilar papilla of the emu (dromaius novaehollandiae). | the emu, being a member of the rather primitive bird group of the palaeognathid ratitae, may reveal primitives features of the avian basilar papilla. there are, however, no qualitative differences with the papillae of other birds such as the chicken or the starling. there are only quantitative differences in the continuous morphological gradients (such as hair cell height, stereovillar height) from neural to abneural, and from the base to the apex of the papilla. only few (about two in the emu) ... | 1998 | 9682814 |
| prevalence of encysted apicomplexans in muscles of raptors. | an acid-pepsin digestion technique was used to examine portions of breast muscle and heart from raptors for encysted protozoans. apicomplexan zoites were present in 52 (45.6%) of the 114 samples examined: 11 of 12 (91.7%) red-shouldered hawks (buteo lineatus), 20 of 34 (58.8%) red-tailed hawks (buteo jamaicensis), two of seven (28.6%) cooper's hawks (accipiter cooperi), three of four (75%) sharp-shinned hawks (accipiter striatus), one (100%) mississippi kites (ictinia misisippiensis), one of two ... | 1999 | 9950339 |
| evolution of time coding systems. | 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. | 1999 | 9950719 |
| postnatal development of the mixed function oxidase system in nestling barn owls and baby chicks and induction of this system in the mature forms by aroclor 1254. | postnatal changes in content and activity of the mixed-function oxidase system in nestling barn owls and baby chicks showed the following: 1. increase in liver weight in both. 2. significantly higher cytochrome p-450 level in 1-day old chicks but lower in 1-day old owls than at any other age. 3. ratio of cytochrome b5 to p-450 was lower than one in nestling owls but higher than one in chicks. 4. aroclor 1254 (pcbs) increased the level and catalytic activity of cytochrome p-450 more in the owl th ... | 1983 | 6135562 |
| linear correlates in the speech signal: the orderly output constraint. | neuroethological investigations of mammalian and avian auditory systems have documented species-specific specializations for processing complex acoustic signals that could, if viewed in abstract terms, have an intriguing and striking relevance for human speech sound categorization and representation. each species forms biologically relevant categories based on combinatorial analysis of information-bearing parameters within the complex input signal. this target article uses known neural models fr ... | 1998 | 10097014 |
| relearning sound localization with new ears. | because the inner ear is not organized spatially, sound localization relies on the neural processing of implicit acoustic cues. to determine a sound's position, the brain must learn and calibrate these cues, using accurate spatial feedback from other sensorimotor systems. experimental evidence for such a system has been demonstrated in barn owls, but not in humans. here, we demonstrate the existence of ongoing spatial calibration in the adult human auditory system. the spectral elevation cues of ... | 1998 | 10196533 |
| distribution of aromatase, estrogen receptor, and androgen receptor mrna in the forebrain of songbirds and nonsongbirds. | androgens and estrogens are crucial for the differentiation and function of the vocal control system of songbirds. a major source of estrogens in songbirds is the cerebral aromatization of circulating testosterone by aromatase (aro). in the vocal control system, songbirds have a unique estrogen receptor (er)-containing area, the nucleus hyperstriatalis ventrale pars caudale (hvc) of the caudal neostriatum. work in the zebra finch has demonstrated aro expression adjacent to but not in the hvc. co ... | 1999 | 10213192 |
| phylogenetic analysis of sarcocystis spp. of mammals and reptiles supports the coevolution of sarcocystis spp. with their final hosts. | sequences of the small subunit rrna genes were obtained for two coccidians, sarcocystis dispersa and an unnamed sarcocystis sp. which parasitise the european barn owl and an african viperid snake as their final host, respectively, and share mouse as their intermediate host. phylogenetic analysis of the sequence data showed that sarcocystis sp. from the viperid snake is most closely related to another sarcocystis sp. isolated from an american crotalid snake, while s. dispersa grouped with other b ... | 1999 | 10404278 |
| low glucokinase activity and high rates of gluconeogenesis contribute to hyperglycemia in barn owls (tyto alba) after a glucose challenge. | barn owls (tyto alba) and leghorn chickens were fed a low protein high glucose (33.44% protein, 23.67% glucose) or a high protein low glucose (55.35% protein, 1.5% glucose) diet. after an intravenous glucose infusion, the peak in plasma glucose was not affected by diet in either species and was 22.6 and 39.4 mmol/l in chickens and barn owls, respectively. glucose levels returned to normal within 30 min in chickens, but remained elevated for 3.5 h in barn owls. an oral glucose challenge also resu ... | 1999 | 10498765 |
| neural coding of relational invariance in speech: human language analogs to the barn owl. | the ability to form perceptual equivalence classes from variable input stimuli is common in both animals and humans. neural circuitry that can disambiguate ambiguous stimuli to arrive at perceptual constancy has been documented in the barn owl's inferior colliculus where sound-source azimuth is signaled by interaural phase differences spanning the frequency spectrum of the sound wave. extrapolating from the sound-localization system of the barn owl to human speech, 2 hypothetical models are offe ... | 1989 | 2798651 |
| horizontal-disparity tuning of neurons in the visual forebrain of the behaving barn owl. | stereovision plays a major role in depth perception of animals having frontally-oriented eyes, most notably primates, cats, and owls. neuronal mechanisms of disparity sensitivity have only been investigated in anesthetized owls so far. in the current study, responses of 160 visual wulst neurons to static random-dot stereograms (rds) were recorded via radiotelemetry in awake, fixating barn owls. the majority of neurons (76%) discharged significantly as a function of horizontal disparity in rds. t ... | 2000 | 10805692 |
| coding interaural time differences at low best frequencies in the barn owl. | 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 del ... | 2004 | 15477025 |
| protein electrophoresis as a diagnostic and prognostic tool in raptor medicine. | plasma proteins of 139 healthy adult birds of prey from 10 species were separated by electrophoresis to characterize and document normal reference ranges and species-specific electrophoretic patternsand to evaluate the value of this technique for health screening, disease diagnosis, and prognostic indication. species studied included bald eagle (haliaeetus leucocephalus), red-tailed hawk (buteo jamaicensis), barn owl (tyto alba), great horned owl (bubo virginianus), turkey vulture (cathartes aur ... | 2000 | 11428396 |
| aliphatic hydrocarbons in birds of prey from galicia (nw spain). | eleven aliphatic hydrocarbons, unresolved over resolved ratio (u/r), carbon preference index (cpi), pristane/c17 ratio, and totals were determined in six classes of tissues (heart, liver, intestine, muscle, lung, and kidney) of 10 buzzards (buteo buteo), 10 barn owls (tyto alba), and five tawny owls (strix aluco) from galicia (nw spain). among individuals detected at quantifiable levels, in general, c18 was found to be the most abundant. total aliphatic hydrocarbons were detected in 77% tissue s ... | 2001 | 11534951 |
| development of sound localization mechanisms in the mongolian gerbil is shaped by early acoustic experience. | sound localization is one of the most important tasks performed by the auditory system. differences in the arrival time of sound at the two ears are the main cue to localize low-frequency sound in the azimuth. in the mammalian brain, such interaural time differences (itds) are encoded in the auditory brain stem; first by the medial superior olive (mso) and then transferred to higher centers, such as the dorsal nucleus of the lateral lemniscus (dnll), a brain stem nucleus that gets a direct input ... | 2005 | 15829592 |
| representation of phonological categories: a functional role for auditory columns. | a speculative model for representing phonological categories for stop place of articulation is offered. the model is analogous to neural columns in both inferotemporal cortex in the macaque for achieving constancy in object recognition and in the inferior colliculus of the barn owl for resolving ambiguous phase disparities for sound localization. hypothetical auditory columns for encoding the vowel context-induced variability of f2 transitions are described using acoustic data from locus equatio ... | 2002 | 11817886 |
| developmental changes underlying the formation of the specialized time coding circuits in barn owls (tyto alba). | barn owls are capable of great accuracy in detecting the interaural time differences (itds) that underlie azimuthal sound localization. they compute itds in a circuit in nucleus laminaris (nl) that is reorganized with respect to birds like the chicken. the events that lead to the reorganization of the barn owl nl take place during embryonic development, shortly after the cochlear and laminaris nuclei have differentiated morphologically. at first the developing owl's auditory brainstem exhibits m ... | 2002 | 12196590 |
| orientation mosaic in barn owl's visual wulst revealed by optical imaging: comparison with cat and monkey striate and extra-striate areas. | using the technique of intrinsic signal optical imaging, orientation preference maps were obtained from the wulst of the barn owl in the area that represents central vision, and from the visual cortices (v1 and v2) of cat and marmoset monkey. iso-orientation domains in barn owl's visual wulst were patch-like structures with an inter-patch distance of approximately 0.9 mm, arranged in a pinwheel-like manner around singularity points. the size of the iso-orientation domains in barn owl was larger ... | 2003 | 12535788 |
| localization of kcnc1 (kv3.1) potassium channel subunits in the avian auditory nucleus magnocellularis and nucleus laminaris during development. | the kcnc1 (previously kv3.1) potassium channel, a delayed rectifier with a high threshold of activation, is highly expressed in the time coding nuclei of the adult chicken and barn owl auditory brainstem. the proposed role of kcnc1 currents in auditory neurons is to reduce the width of the action potential and enable neurons to transmit high frequency temporal information with little jitter. because developmental changes in potassium currents are critical for the maturation of the shape of the a ... | 2003 | 12672015 |
| variation of heavy metals within and among feathers of birds of prey: effects of molt and external contamination. | in this study we examined the effect of external contamination on the heavy metal (ag, al, as, cd, co, cr, cu, fe, hg, mn, ni, pb and zn) concentration in feathers. we compared the heavy metal content among the 10 primary wing feathers of sparrowhawks (accipiter nisus), little owls (athene nocta) and barn owls (tyto alba) and the variation within the outermost tail feather of sparrowhawks and tawny owls (strix aluco). the concentration of hg was significantly higher in feathers molted first, sug ... | 2003 | 12758023 |
| bilaterally-projecting efferent neurones to the basilar papilla in the barn owl and the chicken. | the efferent innervation of the auditory basilar papilla of birds and mammals is provided by a dedicated population of brainstem neurones that are separate from those supplying the vestibular organs. this study addresses the question whether a population of bilaterally-projecting efferents, contacting hair cells in both basilar papillae, is consistently present in birds. the chicken and the barn owl were chosen, two species where the total number of efferents was already known and which represen ... | 2003 | 12965236 |
| comparative analysis of avian bmal1 and clock protein sequences: a search for features associated with owl nocturnal behaviour. | animals differ widely in the phasing of their daily rhythms with respect to daily environmental rhythms. while birds are predominantly day-active, nocturnal activity is a characteristic feature of the order strigiformes (owls). to study the evolution of owl night-activity cdna sequences encoding the circadian core oscillator (cco) proteins bmal1 and clock were obtained from barn owl (tyto alba). the predicted proteins showed high sequence identity with their galliform homologues (bmal1: 99%; clo ... | 2003 | 14662308 |
| modeling coincidence detection in nucleus laminaris. | a biologically detailed model of the binaural avian nucleus laminaris is constructed, as a two-dimensional 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 bi ... | 2003 | 14669019 |
| natural and experimental west nile virus infection in five raptor species. | we studied the effects of natural and/or experimental infections of west nile virus (wnv) in five raptor species from july 2002 to march 2004, including american kestrels (falco sparverius), golden eagles (aquila chrysaetos), red-tailed hawks (buteo jamaicensis), barn owls (tyto alba), and great horned owls (bubo virginianus). birds were infected per mosquito bite, per os, or percutaneously by needle. many experimentally infected birds developed mosquito-infectious levels of viremia (>10(5) wnv ... | 2006 | 16699143 |
| helminth fauna of falconiform and strigiform birds of prey in galicia, northwest spain. | this is a survey of the helminth fauna of 285 individuals of 14 species of birds of prey (falconiformes and strigiformes) from galicia (northwest spain), namely buteo buteo, accipiter nisus, a. gentilis, milvus migrans, m. milvus, pernis apivorus, circus pygargus, falco tinnunculus, f. peregrinus, f. subbuteo, tyto alba, strix aluco, asio otus and athene noctua. a total of 15 helminth species were detected, namely 8 nematodes ( eucoleus dispar, capillaria tenuissima, synhimantus laticeps, microt ... | 2004 | 14714181 |
| a periodic network of neurochemical modules in the inferior colliculus. | a new organization has been found in shell nuclei of rat inferior colliculus. chemically specific modules with a periodic distribution fill about half of layer 2 of external cortex and dorsal cortex. modules contain clusters of small glutamic acid decarboxylase-positive neurons and large boutons at higher density than in other inferior colliculus subdivisions. the modules are also present in tissue stained for parvalbumin, cytochrome oxidase, nicotinamide adenine dinucleotide phosphate-diaphoras ... | 2004 | 14759566 |
| rodenticides in british barn owls. | out of 145 barn owls found dead through accidents (66%), starvation (32%), shooting (2%) and poisoning (<1%), 10% contained residues of rodenticides, difenacoum or brodifacoum, in their livers. difenacoum was in the range 0.005-0.106 microg g(-1) fresh weight, and brodifacoum was in the range 0.019-0.515 microg g(-1). minimum levels of detection were about 0.005 microg g(-1) for both chemicals. mice fed for 1 day on food containing difenacoum and brodifacoum died after 2-11 days. within these mi ... | 1990 | 15092196 |
| arsenic residues in predatory birds from an area of britain with naturally and anthropogenically elevated arsenic levels. | birds of prey forage over large areas and so might be expected to accumulate contaminants which are elevated but heterogeneously distributed in the general environment. the aim of this study was to test the hypothesis that arsenic levels in raptors from a region with elevated environmental arsenic concentrations were higher than those in birds from an uncontaminated part of britain. arsenic concentrations in the liver, kidney and muscle of kestrels, falco tinnunculus, sparrowhawks, accipiter nis ... | 1999 | 15093063 |
| proximate basis of the covariation between a melanin-based female ornament and offspring quality. | in contradiction to sexual selection theory, several studies showed that although the expression of melanin-based ornaments is usually under strong genetic control and weakly sensitive to the environment and body condition, they can signal individual quality. covariation between a melanin-based ornament and phenotypic quality may result from pleiotropic effects of genes involved in the production of melanin pigments. two categories of genes responsible for variation in melanin production may be ... | 2004 | 15248061 |
| female barn owls (tyto alba) advertise good genes. | the good genes hypothesis of sexual selection postulates that ornamentation signals superior genetic quality to potential mates. support for this hypothesis comes from studies on male ornamentation only, while it remains to be shown that female ornamentation may signal genetic quality as well. female barn owls (tyto alba) display more black spots on their plumage than males. the expression of this plumage trait has a genetic basis and it has been suggested that males prefer to mate with females ... | 2000 | 10853738 |
| development of the auditory brainstem of birds: comparison between barn owls and chickens. | birds have proved to be extremely useful models for the study of hearing function. in particular, chickens and barn owls have been widely used by a number of researchers to study diverse aspects of auditory function. these studies have benefited from the advantages offered by each of these two species, including differences of auditory specialization. direct comparisons between chickens and barn owls become complicated when the degree of auditory specialization and their modes of development are ... | 2000 | 10962169 |
| study of sound localization by owls and its relevance to humans. | human psychoacoustical studies have been the main sources of information from which the brain mechanisms of sound localization are inferred. the value of animal models would be limited, if humans and the animals did not share the same perceptual experience and the neural mechanisms for it. barn owls and humans use the same method of computing interaural time differences for localization in the horizontal plane. the behavioral performance of owls and its neural bases are consistent with some of t ... | 2000 | 10989338 |
| expression of the kv3.1 potassium channel in the avian auditory brainstem. | 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 synapto ... | 2001 | 11160428 |
| sensitivity to brief changes of interaural time and interaural intensity. | the purpose of this study was to measure listeners' abilities to detect brief changes in interaural temporal disparities (itds) or interaural intensitive disparities (iids) conveyed by bursts of noise (probes) temporally and symmetrically flanked by segments of diotic or uncorrelated noise. thresholds were measured using a four-interval, two-alternative, forced-choice adaptive task and the total duration of the bursts of noise was either 20, 40, or 100 ms. probes were temporally centered within ... | 2001 | 11325131 |
| tonotopic and somatotopic representation in the nucleus basalis of the barn owl, tyto alba. | we have investigated the somatosensory and auditory representations in the nucleus basalis of the barn owl. in pigeons and finches, the nucleus basalis contains a representation of the beak and an auditory area. in the barn owl, the nucleus basalis also contains a complete somatotopic map of the head and body (as in the budgerigar), with a tonotopically organized auditory area in close proximity to the representation of the facial ruff and the preaural area. recordings within and around the nucl ... | 2001 | 11359047 |
| prevalence of toxoplasma gondii in raptors from france. | little is known about the prevalence or importance of toxoplasma gondii infections in raptors. sera from eurasian buzzards (buteo buteo, n=14), tawny owls (strix aluco, n=12), barn owls (tyto alba, n=18), eurasian sparrowhawk (accipiter nisus, n=1), and common kestrels (falco tinnunculus, n=8) were examined for agglutinating antibodies using the modified agglutination test at 1:25 dilution. antibodies were not detected in common kestrels and the eurasian sparrowhawk but were detected in 11 euras ... | 2008 | 18263835 |
| habitat associations of small mammals in southern brazil and use of regurgitated pellets of birds of prey for inventorying a local fauna. | we inventoried terrestrial small mammals in an agricultural area in southern brazil by using trapping and prey consumed by barn owls (tyto alba) and white-tailed kites (elanus leucurus). small mammals were trapped in three habitat types: corn fields, uncultivated fields ("capoeiras"), and native forest fragments. a total of 1,975 small mammal specimens were trapped, another 2,062 identified from the diet of barn owls, and 2,066 from the diet of white-tailed kites. both trapping and prey in the p ... | 2007 | 18278312 |
| efferent axons in the avian auditory nerve. | the sensory hair cells of the inner ear receive both afferent and efferent innervation. the efferent supply to the auditory organ has evolved in birds and mammals into a separate complex system, with several types of neurons of largely unknown function. in this study, the efferent axons in four different species of birds (chicken, starling, barn owl and emu) were examined anatomically. total numbers of efferents supplying the cochlear duct (auditory basilar papilla and the vestibular lagenar mac ... | 2001 | 11403682 |
| plasma b-esterase activities in european raptors. | b-esterases are serine hydrolases composed of cholinesterases, including acetylcholinesterase (ache) and butyrylcholinesterase (bche), and carboxylesterase (cbe). these esterases, found in blood plasma, are inhibited by organophosphorus (op) and carbamate (cb) insecticides and can be used as nondestructive biomarkers of exposure to anticholinesterase insecticides. furthermore, b-esterases are involved in detoxification of these insecticides. in order to establish the level of these enzymes and t ... | 2005 | 15827224 |
| embryonic and posthatching development of the barn owl (tyto alba): reference data for age determination. | the normal development of the barn owl was documented with the intent of providing a guideline for determining the maturational stage of embryos and posthatching individuals. embryonic development up to stage 39 could be well described using the well-known developmental atlas for the chicken (hamburger and hamilton [1951] j. morphol. 88:49-92). for later stages, limb size was established as a suitable indicator. in addition, measuring the egg's vascularized area through candling was found to be ... | 2005 | 15861405 |
| brominated flame retardants and organochlorine pollutants in aquatic and terrestrial predatory birds of belgium: levels, patterns, tissue distribution and condition factors. | liver and muscle samples from 7 species of aquatic and terrestrial predatory birds from flanders (belgium) were analysed for polychlorinated biphenyls (pcbs), polybrominated diphenylethers (pbdes) and organochlorine pesticides (ocps). pcbs were the predominant compounds in our samples, which showed highest concentrations in the liver of barn owl (tyto alba) and sparrowhawk (accipiter nisus) (up to 1000 microg/g lipid weight). pbdes could be determined in most samples at lower concentrations than ... | 2006 | 16005130 |
| isolation of newcastle disease virus from birds of prey. | in the 4 year period 1971-74 11 isolations of newcastle disease virus (ndv) were made from 44 birds of prey that died in captivity. three species of falconiformes were involved, including one red-headed falcon (falco chicquera), 5 european kestrels (f. tinnunculus), and 2 secretary birds (sagittarius serpentarius), also 2 species of strigiformes, comprising 2 barn owls (tyto alba) and one little owl (athene noctua). all ndv isolates were of the velogenic type. | 1976 | 18777349 |
| the palaeoecology of the micromammals from the late middle pleistocene site of hoedjiespunt 1 (cape province, south africa). | the palaeontological site of hoedjiespunt 1 (hdp1) represents a fossilized hyaena lair. a rich mammalian fauna, including four hominid teeth, has been recovered from the site. micromammals were recovered from the same sediments as the larger fauna. taphonomic analysis suggests that the micromammal assemblages from hdp1 were accumulated by a barn owl. the barn owl produces micromammal assemblages that provide a broad sample of micromammals, within a certain size range, living in the hunting area ... | 2005 | 16045969 |
| occurrence of mycoplasmas in free-ranging birds of prey in germany. | mycoplasmas are well-known avian pathogens of poultry and some passerines. although reported in birds of prey, their role as pathogens is still unclear. healthy, free-ranging raptor nestlings sampled during a routine ringing (banding) program, and birds of prey from rehabilitation centers, tested positive for mycoplasma spp. by culture and a genus-specific polymerase chain reaction (pcr). given the lack of clinical signs and disease, we suggest that mycoplasmas in raptors may be commensal rather ... | 2008 | 18957640 |
| hunting increases adaptive auditory map plasticity in adult barn owls. | the optic tectum (ot) of barn owls contains topographic maps of auditory and visual space. barn owls reared with horizontally displacing prismatic spectacles (prisms) acquire a novel auditory space map in the ot that restores alignment with the prismatically displaced visual map. although juvenile owls readily acquire alternative maps of auditory space as a result of experience, this plasticity is reduced greatly in adults. we tested whether hunting live prey, a natural and critically important ... | 2005 | 16237185 |
| gastrointestinal parasites of owls (strigiformes) kept in captivity in the southern region of brazil. | the aim of this research was to study the gastrointestinal parasitism in 12 adult owls kept in captivity in the southern region of brazil. cloacal contents of the species rhinoptynx clamator, tyto alba, athene cunicularia, megascops spp., and bubo virginianus were evaluated. feces and urine were collected and analyzed by the zinc sulfate centrifugal-flotation method and stained by the modified ziehl-neelsen technique. eggs of capillaria spp. and strongylida, oocysts of cryptosporidium spp., eime ... | 2009 | 19005679 |
| spatial contrast sensitivity of birds. | contrast sensitivity (cs) is the ability of the observer to discriminate between adjacent stimuli on the basis of their differences in relative luminosity (contrast) rather than their absolute luminances. in previous studies, using a narrow range of species, birds have been reported to have low contrast detection thresholds relative to mammals and fishes. this was an unexpected finding because birds had been traditionally reported to have excellent visual acuity and color vision. this study repo ... | 2006 | 16404602 |
| top-down gain control of the auditory space map by gaze control circuitry in the barn owl. | high-level circuits in the brain that control the direction of gaze are intimately linked with the control of visual spatial attention. immediately before an animal directs its gaze towards a stimulus, both psychophysical sensitivity to that visual stimulus and the responsiveness of high-order neurons in the cerebral cortex that represent the stimulus increase dramatically. equivalent effects on behavioural sensitivity and neuronal responsiveness to visual stimuli result from focal electrical mi ... | 2006 | 16421572 |
| interaural timing difference circuits in the auditory brainstem of the emu (dromaius novaehollandiae). | in the auditory system, precise encoding of temporal information is critical for sound localization, a task with direct behavioral relevance. interaural timing differences (itds) 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 n ... | 2006 | 16435285 |
| optimal neural population coding of an auditory spatial cue. | a sound, depending on the position of its source, can take more time to reach one ear than the other. this interaural (between the ears) time difference (itd) provides a major cue for determining the source location. many auditory neurons are sensitive to itds, but the means by which such neurons represent itd is a contentious issue. recent studies question whether the classical general model (the jeffress model) applies across species. here we show that itd coding strategies of different specie ... | 2004 | 15295602 |
| protean behavior under barn-owl attack: voles alternate between freezing and fleeing and spiny mice flee in alternating patterns. | when attacking a spiny mouse in an experimental arena, a barn owl launched a few attacks from distant perches, made repetitive short-distance swoops in each attack and remained in the vicinity of the prey while chasing it. the spiny mouse fled in response, and typically oriented to face the owl whenever it stopped. when attacking a vole, the barn owl performed a greater number of attacks from distant perches, and left the vicinity of the prey after a few short-distance chases or capture attempts ... | 2004 | 15364479 |
| evaluation of secondary poisoning of difethialone, a new second-generation anticoagulant rodenticide to barn owl, tyto alba hartert under captivity. | secondary toxcity of difethialone to barn owl (tyto alba) has been investigated. difethialone was fed to owls for successive periods of 1 (phase 1), 3 (phase 2) and 6 (phase 3) days via-rodenticide dosed rats. the owls survived after the treament of rodenticide on phase 1 and phase 2 experiments but they died during phase 3 experiment. the results suggest that the difethialone could cause more secondary toxicity to owls. | 2004 | 15511007 |
| isolation and characterization of major histocompatibility complex (mhc) class ii b genes in the barn owl (aves: tyto alba). | we isolated major histocompatibility complex class ii b (mhciib) genes in the barn owl (tyto alba). a pcr-based approach combined with primer walking on genomic and complementary dna as well as southern blot analyses revealed the presence of two mhciib genes, both being expressed in spleen, liver, and blood. characteristic structural features of mhciib genes as well as their expression and high non-synonymous substitution rates in the region involved in antigen binding suggest that both genes ar ... | 2008 | 18548243 |
| deaths in free-living barn owls (tyto alba). | pathological examinations were made on 20 free-living barn owls, tyto alba, that died during winter-spring 1985 victoria, australia. starvation was the likely cause of the deaths with all the birds being in poor condition and markedly underweight (235 to 265 g). the owls had suffered a massive decline in the abundance of their prey, the house mouse, mus musculus, following the end of a mouse plague. the life cycle of the barn owl makes it susceptible to deaths due to starvation following seasona ... | 1989 | 18679905 |
| accuracy and reproducibility of the tonovet rebound tonometer in birds of prey. | to examine the accuracy and reproducibility of intraocular pressure (iop) measurements obtained by the tonovet rebound tonometer. animals studied freshly enucleated healthy eyes of 44 free-ranging birds of prey out of the species haliaeetus albicilla, accipiter gentilis, accipiter nisus, buteo buteo, falco tinnunculus, strix aluco, asio otus and tyto alba euthanized because of unrelated health problems. | 2010 | 20840094 |