Publications

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a neurophysiological determination of the vertical horopter in the cat and owl.we have undertaken a determination of the vertical horopter in two species by simultaneously mapping the receptive field positions of binocular cortical neurons at various elevations along the zero azimuthal meridians. in the paralyzed cat our recordings show that the zero meridians of the two eyes are parallel and vertical under paralysis. slit-pupil photographs demonstrate that paralysis induces an average net intorsin of 9 degrees between the two eyes. correction back to the unparalyzed state ...1979762277
comparison of intrapulmonary chemoreceptor response to pco2 in the duck and chicken.intrapulmonary chemoreceptors (ipc) in the burrowing owl are reported to be much less sensitive to pco2 than ipc in the chicken. this blunted ipc sensitivity has been suggested to be a physiological adaptation to hypercapnic subterranean environments. to investigate the natural variation ipc responses in non-burrowing species, stimulus-response characteristics of 87 ipc in 22 anesthetized pekin ducks were recorded and compared to those from 54 previously reported chicken ipc. average logarithmic ...19853931192
ventilatory and intrapulmonary chemoreceptor sensitivity to co2 in the burrowing owl.we measured the ventilatory response of anesthetized, unidirectionally ventilated pigeons and burrowing owls to changes in intrapulmonary co2 concentration and the static co2 sensitivity of intrapulmonary chemoreceptors (ipc) in these species and the domestic goose. compared with pigeons, burrowing owls showed a significantly reduced respiratory frequency and amplitude response to increases in fico2 from 0.05 to 0.10, which corroborates similar findings in intact, awake individuals of the same s ...19853937191
neural connections of the "visual wulst" of the avian telencephalon. experimental studies in the piegon (columba livia) and owl (speotyto cunicularia). 19734721779
some neural connections subserving binocular vision in ungulates.using a combination of anatomical and physiological techniques we have studied some of the neural connections subserving binocular vision in two species of artiodactyl ungulates (the sheep, ovis sp., and the goat, capra hircus). after monocular injections of tritiated proline, transsynaptic transport was observed bilaterally in layers 4 and 6 of visual cortical areas v1 and v2, but there were no sharply defined ocular dominance columns of the kind seen in cats and rhesus monkeys. in coronal sect ...19846466965
a modified protocol for sex identification of in ovo avian embryos and its application as a management tool for endangered species conservation programs.a simple, reliable, and safe protocol was developed for the collection of small amounts of blood from avian eggs of variable size and at early stages of development. fifty eggs were used in the study; 40 were common chicken (gallus domesticus) eggs, six were homing pigeon (columba livia domestica) eggs, and four were burrowing owl (athene cunicularia) eggs. collection was attempted approximately halfway through incubation. the success rate for collection of blood or blood-tinged fluid from eggs ...200112790417
black-tailed prairie dogs and the structure of avian communities on the shortgrass plains.we tested the hypothesis that black-tailed prairie dogs (cynomys ludovicianus) influence avian community structure on the shortgrass prairie. we surveyed 36 prairie dog towns and 36 paired sites without prairie dogs during summer and fall of 1997, 1998, and 1999 in the oklahoma panhandle. our surveys totaled 9,040 individual observations for 73 avian species. significantly distinct avian communities were present on prairie dog towns when compared to sites within four different macrohabitats of t ...200414685848
animal behaviour: use of dung as a tool by burrowing owls.reports of tool usage by birds tend to be anecdotal as only a few individuals may be involved and the behaviour observed can often be interpreted in other ways. here we describe the widespread collection of mammalian dung by burrowing owls (athene cunicularia) and show that they use this dung as a bait to attract dung beetles, a major item of prey. our controlled investigation provides an unambiguous estimate of the importance of tool use in a wild animal.200415343324
first detection of bacillus anthracis in feces of free-ranging raptors from central argentina.prevalence of anthrax spores in feces of raptors was determined from samples collected in november-december 2000 and april-may 2001 in an agricultural region of santa fé province, argentina. feces were tested from 48 birds of six raptor species. one of 14 chimango caracaras (milvago chimango) and one of eight road-side hawks (buteo magnirostris) tested positive. the prevalence of bacillus anthracis spores in feces for the six species was 4% (n=48). the prevalence was 7% (n=14) for chimango carac ...200717347404
the role of the burrowing owl and the sticktight flea in the spread of plague. 194117821262
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 ...200919005679
individual consistency in flight initiation distances in burrowing owls: a new hypothesis on disturbance-induced habitat selection.individuals often consistently differ in personalities and behaviours that allow them to cope with environmental variation. flight initiation distance (fid) has been measured in a variety of taxa as an estimate of the risk that an individual is willing to take when facing a predator. fid has been used to test life-history trade-offs related to anti-predatory behaviour and for conservation purposes such as to establish buffer zones to minimize human disturbance, given its species-specific consist ...201019864278
occurrence of west nile virus infection in raptors at the salton sea, california.we investigated the prevalence of west nile virus (wnv)-neutralizing antibodies and infectious virus, and the occurrence of overwinter transmission in two raptor species during january and march 2006 at the salton sea, imperial county, california. we captured 208 american kestrels (falco sparverius) (january, n=100; march, n=108) and 116 burrowing owls (athene cunicularia) (january, n=52; march, n=64). laboratory analysis revealed that 83% of american kestrels and 31% of burrowing owls were posi ...201020688694
serologic evidence of toxoplasma gondii infection in wild birds and mammals from southeast brazil.in this study, serum samples of 53 wild animals from two different states from the southeast region of brazil were analyzed for the presence of anti-toxoplasma gondii antibodies by the modified agglutination test (mat), with a cut-off of 1: 5 for birds and of 1: 25 for mammals. out of the sampled animals, 27 were birds and 26 were mammals, and from this total, 83% (n = 44) were free-living animals. antibodies were found in 13 mammals, from which 11 were free-living animals, and in five birds, al ...201424712186
burrowing owls, pulex irritans, and plague.western burrowing owls (athene cunicularia hypugaea) are small, ground-dwelling owls of western north america that frequent prairie dog (cynomys spp.) towns and other grasslands. because they rely on rodent prey and occupy burrows once or concurrently inhabited by fossorial mammals, the owls often harbor fleas. we examined the potential role of fleas found on burrowing owls in plague dynamics by evaluating prevalence of yersinia pestis in fleas collected from burrowing owls and in owl blood. dur ...201526367482
numerical and functional response of predators to a long-term decline in mammalian prey at a semi-arid neotropical site.occurrence and diet of ten carnivorous predators (four falconiforms, four owls, and two foxes), and population levels of their mammalian prey, were monitored over 45 months at a semi-arid site in north-central chile. early in this period, small mammals irrupted and then declined markedly to a density 7% of that at peak. all four falconiforms (buteo polyosoma, falco sparverius, geranoaetus melanoleucus, parabuteo unicinctus) and one owl (tyto alba) responded numerically to the decline in mammalia ...199228313400
effects of military training activities on shrub-steppe raptors in southwestern idaho, usa./ between 1991 and 1994, we assessed relative abundance, nesting success, and distribution of ferruginous hawks (buteo regalis), northern harriers (circus cyaneus), burrowing owls (athene cunicularia), and short-eared owls (asio flammeus) inside and outside a military training site in the snake river birds of prey national conservation area, southwestern idaho. the orchard training area is used primarily for armored vehicle training and artillery firing by the idaho army national guard. relative ...19999950702
comparative physiology of sound localization in four species of owls.bilateral ear asymmetry is found in some, but not all, species of owls. we investigated the neural basis of sound localization in symmetrical and asymmetrical species, to deduce how ear asymmetry might have evolved from the ancestral condition, by comparing the response properties of neurons in the external nucleus of the inferior colliculus (icx) of the symmetrical burrowing owl and asymmetrical long-eared owl with previous findings in the symmetrical great horned owl and asymmetrical barn owl. ...19902279234
new records of three hippoboscid species on newly captured birds from nature in paraná, brazil.the aims of this study was to provide new records of hippoboscid flies collected over an one-year period on newly captured birds from nature in the state of paraná, brazil. the birds were received by a wildlife center in tijucas do sul and the hippoboscid flies were collect by hand or by tweezers, generating a prevalence of 0.7% (16/2232) of parasitized birds. new information about distribution of hippoboscid flies on asio clamator, rupornis magnirostris and athene cunicularia was reported in th ...201627737369
diversity of quill mites of the family syringophilidae (acari: prostigmata) parasitizing owls (aves: strigiformes) with remarks on the host-parasite relationships.the quill mite fauna of the family syringophilidae (acari: prostigmata: cheyletoidea) associated with owls (aves: strigiformes) is reviewed. a new genus is proposed, neobubophilus skoracki & unsoeld gen. nov. it differs from closely related bubophilus (bubophilus philips and norton, 1978) by the absence of leg setae vsii in the both sexes. in addition, four new species are described: (1) neobubophilus cunicularius skoracki & unsoeld sp. nov. from athene cunicularia (molina, 1782) (strigidae) fro ...201627220744
mortality of western burrowing owls ( athene cunicularia hypugaea) associated with brodifacoum exposure.western burrowing owls ( athene cunicularia hypugaea) frequently occupy periurban areas, where they may be exposed to pest control agents. this short communication describes necropsy findings and detected brodifacoum rodenticide levels for four western burrowing owls in lake havasu city, arizona, us, 2013-15. levels detected ranged from 0.077 mg/kg to 0.497 mg/kg. brodifacoum, one of several second-generation anticoagulant rodenticides recently removed from the general consumer market, is still ...201727763828
population density of the western burrowing owl (athene cunicularia hypugaea) in mexican prairie dog (cynomys mexicanus) colonies in northeastern mexico.the western burrowing owl (athene cunicularia hypugaea) occurs throughout western north america in various habitats such as desert, short-grass prairie and shrub-steppe, among others, where the main threat for this species is habitat loss. range-wide declines have prompted a need for reliable estimates of its populations in mexico, where the size of resident and migratory populations remain unknown.201627566259
heritability of fear of humans in urban and rural populations of a bird species.flight initiation distance (fid), a measure of an animal's tolerance to human disturbance and a descriptor of its fear of humans, is increasingly employed for conservation purposes and to predict the response of species to urbanization. however, most work devoted to understanding variability in fid has been conducted at the population level and little is still known about inter-individual variability in this behaviour. we estimated the heritability of fid, a factor fundamental to understanding t ...201627499420
contrast response functions in the visual wulst of the alert burrowing owl: a single-unit study.the neuronal representation of luminance contrast has not been thoroughly studied in birds. here we present a detailed quantitative analysis of the contrast response of 120 individual neurons recorded from the visual wulst of awake burrowing owls (athene cunicularia). stimuli were sine-wave gratings presented within the cell classical receptive field and optimized in terms of eye preference, direction of drift, and spatiotemporal frequency. as contrast intensity was increased from zero to near 1 ...201627466135
differential risk perception of rural and urban burrowing owls exposed to humans and dogs.urban areas expose wildlife to an array of novel predators, amongst which, humans and dogs are highly frequent. thus, wild animals living in urban areas are forced to invest more time and energy in defence behaviours, which depend on how the risk is perceived and assessed. we experimentally tested whether burrowing owls coming from rural and urban habitats showed differences in behavioural responses when facing humans and domestic dogs. we measured flight initiation distances (fids), nest return ...201626718884
detecting burrowing owl bloodmeals in pulex irritans (siphonaptera: pulicidae).pulex irritans l. is a cosmopolitan flea species that infests a wide variety of hosts. in north america it generally parasitizes large wild mammals, but in the pacific northwest an association has emerged between p. irritans and the western burrowing owl (athene cunicularia hypugaea). while investigators have recognized this association for decades, it has not been clear if p. irritans feeds on burrowing owls, or if the owls serve exclusively as phoretic hosts. here we describe using a real-time ...201626545716
rapid warming and drought negatively impact population size and reproductive dynamics of an avian predator in the arid southwest.avian communities of arid ecosystems may be particularly vulnerable to global climate change due to the magnitude of projected change for desert regions and the inherent challenges for species residing in resource limited ecosystems. how arid-zone birds will be affected by rapid increases in air temperature and increased drought frequency and severity is poorly understood because avian responses to climate change have primarily been studied in the relatively mesic northern temperate regions. we ...201626367541
new record of pelecitus sp. (nematoda, onchocercidae) as a parasite of athene cunicularia (strigiformes, strigidae) in southeastern brazil.the aim of this study was to report the burrowing owl athene cunicularia as a new host for the filarid nematode pelecitus sp. in southeastern brazil for the first time, as well as reporting the occurrence of this nematode species in the body cavity, near the cervical air sac and lung region. this study contributes towards knowledge of parasitism in brazilian wild birds and an anatomical region of the host as an infection site for pelecitus sp.201425054513
high urban breeding densities do not disrupt genetic monogamy in a bird species.urbanization causes widespread endangerment of biodiversity worldwide. however, some species successfully colonize cities reaching higher densities than in their rural habitats. in these cases, although urban city dwellers may apparently be taking advantage of these new environments, they also face new ecological conditions that may induce behavioural changes. for example, the frequency of alternative reproductive behaviours such as extra-pair paternity and intraspecific brood parasitism might i ...201424614308
comparing food limitation among three stages of nesting: supplementation experiments with the burrowing owl.food availability is an important limiting factor for avian reproduction. in altricial birds, food limitation is assumed to be more severe during the nestling stage than during laying or incubation, but this has yet to be adequately tested. using food-supplementation experiments over a 5-year period, we determined the degree and timing of food limitation for burrowing owls (athene cunicularia) breeding in canada. burrowing owls are an endangered species and food limitation during the nestling st ...201324567832
selection and implementation of a flagship fleet in a locally undervalued region of high endemicity.flagships are one conservation education tool. we present a proposed flagship species fleet for environmental education in central chile. our methods followed recent flagship guidelines. we present our selection process and a detailed justification for the fleet of flagship species that we selected. our results are a list of eight flagship species forming a flagship fleet, including two small- and medium-sized mammals, the degu (octodon degus) and the culpeo fox (lycalopex culpeaus), two birds, ...201323479265
associations of grassland bird communities with black-tailed prairie dogs in the north american great plains.colonial burrowing herbivores can modify vegetation structure, create belowground refugia, and generate landscape heterogeneity, thereby affecting the distribution and abundance of associated species. black-tailed prairie dogs (cynomys ludovicianus) are such a species, and they may strongly affect the abundance and composition of grassland bird communities. we examined how prairie dog colonies in the north american great plains affect bird species and community composition. areas occupied by pra ...201323330695
surgical removal of a thymoma in a burrowing owl (athene cunicularia).a 12-year-old male burrowing owl (athene cunicularia) was presented for evaluation of a mass in the right cervical region. a thymoma was diagnosed after surgical resection and histopathologic evaluation. extensive adherence of the thymoma to the esophagus and suspected invasion into the right jugular vein contributed to a poor postsurgical outcome. diagnosis and treatment of thymomas in avian species is similar to that in mammals. surgical removal of noninvasive thymomas is usually curative. thy ...201222872980
migratory decisions in birds: extent of genetic versus environmental control.migration is one of the most spectacular of animal behaviors and is prevalent across a broad array of taxa. in birds, we know much about the physiological basis of how birds migrate, but less about the relative contribution of genetic versus environmental factors in controlling migratory tendency. to evaluate the extent to which migratory decisions are genetically determined, we examined whether individual western burrowing owls (athene cunicularia hypugaea) change their migratory tendency from ...200919437042
ventilatory and metabolic responses of burrowing owls, athene cunicularia, to moderate and extreme hypoxia: analysis of the hypoxic ventilatory threshold vs. hemoglobin oxygen affinity relationship in birds.we measured ventilation, oxygen consumption and blood gases in burrowing owls (athene cunicularia) breathing moderate and extreme hypoxic gas mixtures to determine their hypoxic ventilatory threshold (hvt) and to assess if they, like other birds and mammals, exhibit a relationship between hvt and hemoglobin o2 affinity (p(50)) of their blood. an earlier report of an attenuated ventilatory responsiveness of this species to hypoxia was enigmatic given the low o2 affinity (high p(50)) of burrowing ...200817561426
an analysis of spatial clustering and implications for wildlife management: a burrowing owl example.analysis tools that combine large spatial and temporal scales are necessary for efficient management of wildlife species, such as the burrowing owl (athene cunicularia). we assessed the ability of ripley's k-function analysis integrated into a geographic information system (gis) to determine changes in burrowing owl nest clustering over two years at nasa ames research center. specifically, we used these tools to detect changes in spatial and temporal nest clustering before, during, and after con ...200717253092
concentration of contaminants in breeding bird eggs from the colorado river delta, mexico.organic contaminants (organochlorine [oc], organophosphorus [op] pesticides and polychlorinated biphenyls [pcbs]), and metals (as, cd, hg, pb, and se) are a concern to avian health in the colorado river delta, mexico. we determined concentrations of contaminants in eggs of three breeding species of birds from the delta (mourning doves [zenaida macroura], burrowing owls [athene cunicularia], and marsh wrens [cistothorus palustris]). we collected 27 eggs of mourning doves, eight eggs of burrowing ...200616764484
interactive effects of prey and p,p'-dde on burrowing owl population dynamics.we used population models to explore the effects of the organochlorine contaminant p,p'-dde and fluctuations in vole availability on the population dynamics of burrowing owls (athene cunicularia). previous work indicated an interaction between low biomass of voles in the diet and moderate levels of p,p'-dde in burrowing owl eggs that led to reproductive impairment. we constructed periodic and stochastic matrix models that incorporated three vole population states observed in the field: average, ...200616711053
hatching asynchrony in burrowing owls is influenced by clutch size and hatching success but not by food.in most animals, siblings from a given reproductive event emerge over a very short period of time. in contrast, many species of birds hatch their young asynchronously over a period of days or weeks, handicapping last-hatched chicks with an age and size disadvantage. numerous studies have examined the adaptive significance of this atypical hatching pattern, but few have attempted to explain the considerable intrapopulation variation that exists in hatching asynchrony. i explored proximate determi ...200515480800
effectiveness of voluntary habitat stewardship in conserving grassland: case of operation burrowing owl in saskatchewan.there have been no published performance evaluations of nongovernmental, voluntary habitat stewardship programs. the operation burrowing owl (obo) stewardship program, initiated in 1987, was evaluated for its effectiveness in conservation of grassland habitat during 1986-1993. the 108 obo sites from 1987 to 88 and 98 randomly selected non-obo sites that were grassland in 1986 in the regina-weyburn, saskatchewan study area were classified by size and agricultural soil suitability. by 1993, 41 (38 ...200415037954
the rattling sound of rattlesnakes (crotalus viridis) as a communicative resource for ground squirrels (spermophilus beecheyi) and burrowing owls (athene cunicularia).animal communication involves very dynamic processes that can generate new uses and functions for established communicative activities. in this article, the authors describe how an aposematic signal, the rattling sound of rattlesnakes (crotalus viridis), has been exploited by 2 ecological associates of rattlesnakes: (a) california ground squirrels (spermophilus beecheyi) use incidental acoustic cues in rattling sounds to assess the danger posed by the rattling snake, and (b) burrowing owls (athe ...200212083617
radiation exposure and dose to small mammals in radon-rich soils.protection of the environment from radionuclide releases requires knowledge of the normal background levels of radiation exposure in the exposed biotic community and an estimate of the detriment caused by additional exposure. this study modeled the background exposure and dose to the lungs of small burrowing mammals from 222rn in artificial burrows in radon-rich soils at a site in southeastern manitoba. e-perm chambers used to measure 222rn in soil showed good reproducibility of measurement, wit ...19989601928
hypopi (acari:hypoderatidae) from owls (aves:strigiformes:strigidae).hypopi (deutonymphs) of the family hypoderatidae were found in a barn owl, tyto alba (scopoli), and a burrowing owl, speotyto cunicularia (molina), from texas. a redescription is provided for mature specimens of the hypopus of tytodectes (tytodectes) tyto fain from the subcutaneous adipose tissues of the pelvic region in the barn owl. the hypopus of tytodectes (tytodectes) speotyto n. sp. is described from specimens in the subcutaneous adipose tissues of the pelvic region and in the adipose tiss ...19968840691
extirpation of alternative prey during a small rodent crash.we document two episodes, in different years, of barn owls (tyto alba) preying on a winter population of burrowing owls (athene cunicularia) on a southern california island. the predation in each case followed a marked shift in the diet of the barn owls, due to the cyclic decline of their normal small mammal prey. heavy predation in the first year resulted in the extirpation of the burrowing owls on the island. such heavy predation on alternative prey species is commonly reported in cyclic preda ...199228313067
blood oxygen binding properties for the burrowing owl, athene cunicularia.isocapnic o2 equilibrium curves (o2ecs) were generated for whole blood of 4 adult burrowing owls (athene cunicularia) using thin film techniques. at in vivo pha (7.49 +/- 0.02; mean +/- 1 sem) and 41 degrees c, the po2 at half saturation (p50) was 42.3 +/- 0.8 torr. co2 and fixed acid (h+) bohr slopes (delta log p50/delta ph) were -0.46 +/- 0.01 and -0.42 +/- 0.02, respectively, demonstrating a small specific co2 effect. co2 and h+ bohr slopes were saturation-independent between 0.1 and 0.9 s. h ...19892749025
blood characteristics, tracheal volume and heart mass of burrowing owls (athene cunicularia) and bobwhite (colinus virginianus).1. measurements of certain hematological and morphological characteristics were made in burrowing owls and bobwhite in search of features that could be associated with the previously described ventilatory adaptations of the burrowing owl to hypoxia and hypercarbia. 2. values for burrowing owls and bobwhite, respectively, were: p50 = 44.9, 46.0 torr; hct = 36.6, 38.8 vol%, hb = 12, 12.3 (g/100 ml); rbc = 2.72 x 10(6), 3.02 x 10(6); log p50/ph = -0.412, -0.485; delta log pco2/delta ph = -1.39, -1. ...19836132713
the distribution of neurons projecting from the retina and visual cortex to the thalamus and tectum opticum of the barn owl, tyto alba, and the burrowing owl, speotyto cunicularia.using the hrp retrograde transport technique in two different genera of owls (speotyto and tyto), we have studied the distribution of neurons projecting to the optic tectum and the visual thalamus. small injections of hrp were made into these structures from the pial surface after they had been visualized directly by dissection of the overlying bone. in contrast to the findings in mammals, retinal ganglion cells were labeled only in the eye contralateral to the injection site, whether this was i ...19817263955
the guild structure of a community of predatory vertebrates in central chile.the trophic ecology of eleven predator species (falconiforms: buteo polyosoma, elanus leucurus, falco sparverius, geranoaetus melanoleucus, parabuteo unicinctus; strigiforms: athene cunicularia, bubo virginianus, tyto alba; carnivores: dusicyon culpaeus; snakes: philodryas chamissonis, tachymenis peruviana) in two nearby localities of central chile is analyzed. the localities exhibit the typical climate (hot-dry summers, coldrainy winters), and vegetation (chaparral), of mediterranean ecosystems ...198128309444
echinoparyphium speotyto sp. n. (trematoda: echinostomatidae) from the burrowing owl in oklahoma, with a discussion of the genus echinoparyphium. 1978627976
sleep in the burrowing owl (speotyto cunicularia hypugaea). 19724339456
water turnover in coturnix quail with individual observations on a burrowing owl, petz conure and vulturine fish eagle. 19714398986
two new species and new records of nasal mites of the genus sternostoma (acarina: rhinonyssinae) from birds in texas.two new species and new host and locality records are established for nasal mites of the genus sternostoma from birds in texas. sternostoma tracheacolum lawrence is reported for the first time from pipilo fuscus and pyrrhuloxia sinuata, respectively. additionally, a new host record for sternostoma porteri hyland from centurus aurifrons and a new locality record for sternostoma pirangae pence from piranga rubra are established. a redescription is provided for sternostoma augei amaral from speotyt ...19751127568
predation-risk effects of predator identity on the foraging behaviors of frugivorous bats.predators directly and indirectly affect the density and the behavior of prey. these effects may potentially cascade down to lower trophic levels. in this study, we tested the effects of predator calls (playbacks of bird vocalizations: tyto alba, speotyto cunicularia, and vanellus chilensis), predator visual stimuli (stuffed birds) and interactions of visual and auditory cues, on the behavior of frugivore phyllostomid bats in the field. in addition, we tested if the effects of predation risk cas ...201323657559
urban conservation hotspots: predation release allows the grassland-specialist burrowing owl to perform better in the city.although habitat transformation is one of the main causes of biodiversity loss, there are many examples of species successfully occupying and even proliferating in highly human-modified habitats such are the cities. thus, there is an increasing interest in understanding the drivers favoring urban life for some species. here, we show how the low richness and abundance of predators in urban areas may explain changes in the habitat selection pattern of a grassland specialist species, the burrowing ...201728615700
insights into the introduction history and population genetic dynamics of the nile monitor (varanus niloticus) in florida.invasive species are widely recognized as important drivers of the ongoing biodiversity crisis. the us state of florida is especially susceptible to the proliferation of invasive reptiles, and nonnative lizards currently outnumber native lizard species. at present, there are 3 documented breeding populations of the nile monitor (varanus niloticus) in different regions of southern florida, and these populations are considered potential dangers to threatened, fossorial endemics, such as burrowing ...201626971010
links between fear of humans, stress and survival support a non-random distribution of birds among urban and rural habitats.urban endocrine ecology aims to understand how organisms cope with new sources of stress and maintain allostatic load to thrive in an increasingly urbanized world. recent research efforts have yielded controversial results based on short-term measures of stress, without exploring its fitness effects. we measured feather corticosterone (cortf, reflecting the duration and amplitude of glucocorticoid secretion over several weeks) and subsequent annual survival in urban and rural burrowing owls. thi ...201526348294
using vertebrate prey capture locations to identify cover type selection patterns of nocturnally foraging burrowing owls.studies of habitat selection often measure an animal's use of space via radiotelemetry or gps-based technologies. such data tend to be analyzed using a resource selection function, despite the fact that the actual resources acquired are typically not recorded. without explicit proof of resource use, conclusions from rsf models are based on assumptions regarding an animal's behavior and the resources gained. conservation initiatives are often based on space-use models, and could be detrimental to ...201425154089
high individual consistency in fear of humans throughout the adult lifespan of rural and urban burrowing owls.human-induced rapid environmental changes challenge individuals by creating evolutionarily novel scenarios, where species encounter novel enemies, the new species sometimes being humans themselves. however, little is known about how individuals react to human presence, specifically whether they are able to habituate to human presence, as frequently assumed, or are selected based on their fear of humans. we tested whether fear of humans (measured as flight initiation distance in a diurnal owl) is ...201324343659
spatiotemporal frequency and speed tuning in the owl visual wulst.the avian visual wulst is hodologically equivalent to the mammalian primary visual cortex (v1). in contrast to most birds, owls have a massive visual wulst, which shares striking functional similarities with v1. to provide a better understanding of how motion is processed within this area, we used sinusoidal gratings to characterize the spatiotemporal frequency and speed tuning profiles of 131 neurones recorded from awake burrowing owls. cells were found to be clearly tuned to both spatial and t ...200919788573
directional responses of visual wulst neurones to grating and plaid patterns in the awake owl.the avian retinothalamofugal pathway reaches the telencephalon in an area known as visual wulst. a close functional analogy between this area and the early visual cortex of mammals has been established in owls. the goal of the present study was to assess quantitatively the directional selectivity and motion integration capability of visual wulst neurones, aspects that have not been previously investigated. we recorded extracellularly from a total of 101 cells in awake burrowing owls. from this s ...200717897399
low prevalence of west nile virus antibodies in select northern california owl species (2007-2014).the objective of this study was to determine evidence of previous west nile virus (wnv) infection in northern california owls. owl serum samples were collected from birds presenting to a veterinary medical teaching hospital between 2007 and 2014 and were screened for the presence of wnv antibodies by an indirect enzyme immunoassay (eia). only one of 71 samples (1.41%) tested was positive by eia and confirmed by a plaque reduction neutralization test; it was the most recent sample collected. the ...201729297801
genomic evidence for parallel adaptation to cities.urban evolutionary biology is the study of rapid evolutionary change in response to humans and our uses of land to support city dwellers. because cities are relatively modern additions to the natural world, research on urban evolution tends to focus on microevolutionary change that has happened across a few to many hundreds of generations. these questions still fall under the broad purview of evolutionary ecology. however, the severity, rapidity and replication of environmental changes that driv ...202032772443
differences in adrenocortical responses between urban and rural burrowing owls: poorly-known underlying mechanisms and their implications for conservation.the hypothalamus-pituitary-adrenal/interrenal (hpa) axis of vertebrates integrates external information and orchestrates responses to cope with energy-demanding and stressful events through changes in circulating glucocorticoid levels. urbanization exposes animals to a wide variety of ever-changing stimuli caused by human activities that may affect local wildlife populations. here, we empirically tested the hypothesis that urban and rural owls (athene cunicularia) show different adrenocortical r ...202032665848
sex, personality and conspecific density influence natal dispersal with lifetime fitness consequences in urban and rural burrowing owls.there is a growing need to understand how species respond to habitat changes and the potential key role played by natal dispersal in population dynamics, structure and gene flow. however, few studies have explored differences in this process between conspecifics living in natural habitats and those inhabiting landscapes highly transformed by humans, such as cities. here, we investigate how individual traits and social characteristics can influence the natal dispersal decisions of burrowing owls ...202032049995
personality-dependent breeding dispersal in rural but not urban burrowing owls.dispersal propensity has been correlated with personality traits, conspecific density and predation risk in a variety of species. thus, changes in the relative frequency of behavioural phenotypes or in the ecological pressures faced by individuals in contrasting habitats can have unexpected effects on their dispersal strategies. here, using the burrowing owl athene cunicularia as a study model, we test whether changes in the behavioural profile of individuals and changes in conspecific density a ...201930814548
the role of habituation in the adjustment to urban life: an experimental approach with burrowing owls.birds exhibit variation in fear behaviour in response to an approaching human within and between species and across different habitat contexts. we analyze urban and rural burrowing owls' variation in risk perception along separate but consecutive days (treatment 1) and risk perception within the same day (treatment 2). fear behaviour was measured as flight initiation distances (fids) and aggressiveness level when a pedestrian approached repeatedly to an owl individual. we predict that the attenu ...201830359692
the use of sulfur hexafluoride microbubbles for contrast-enhanced ocular ultrasonography of the pecten oculi in birds.the pecten oculi is a vascular and pigmented structure localized within the posterior segment of all avian eyes. its primary function is not fully understood yet.201930109756
burrowing owls eavesdrop on southern lapwings' alarm calls to enhance their antipredatory behaviour.eavesdropping is a widespread behaviour among animals, providing the receiver with valuable information to assess the habitat, resources or threats. this kind of behaviour has been reported for the burrowing owl (athene cunicularia), which in its northern range lives in close association with fossorial mammals and eavesdrops on their alarm calls as indicators of risk. in their southernmost range, burrowing owls do not associate with mammals, but they are often found sharing foraging and nesting ...201830308234
lws visual pigment in owls: spectral tuning inferred by genetics.owls constitute a diverse group of raptors, active at different times of the day with distinct light conditions that might be associated with multiple visual adaptations. we investigated whether shifts in the spectral sensitivity of the l cone visual pigment, as inferred by analysis of gene structure, could be one such adaptive mechanism. using sanger sequencing approach, we characterized the long wavelength-sensitive (lws) opsin gene expressed in the retina of five owl species, specifically cho ...201931706045
agriculture creates subtle genetic structure among migratory and nonmigratory populations of burrowing owls throughout north america.population structure across a species distribution primarily reflects historical, ecological, and evolutionary processes. however, large-scale contemporaneous changes in land use have the potential to create changes in habitat quality and thereby cause changes in gene flow, population structure, and distributions. as such, land-use changes in one portion of a species range may explain declines in other portions of their range. for example, many burrowing owl populations have declined or become e ...202033072290
biomonitoring of owls and their environment using pellets and feathers.owls are predators that perform important ecological functions. there are several threats to owl conservation such as the bioaccumulation of chemicals through environmental contamination. the high probability of bioaccumulation in these animals is related to their role as predators and high trophic positions. the objective of this study was to quantify four elements (cadmium, chromium, nickel, and lead) as the biomarkers of environmental exposure in owls. to this end, we analyzed pellets and fea ...202033067667
genes acting in synapses and neuron projections are early targets of selection during urban colonization.when a species colonizes an urban habitat, differences in the environment can create novel selection pressures. successful colonization will further lead to demographic perturbations and genetic drift, which can interfere with selection. here, we test for consistent urban selection signals in multiple populations of the burrowing owl (athene cunicularia), a species that colonized south american cities just a few decades ago. we sequenced 213 owls from three urban-rural population pairs and perfo ...202032310323
author correction: personality-dependent breeding dispersal in rural but not urban burrowing owls.an amendment to this paper has been published and can be accessed via a link at the top of the paper.202031992817
correction for "interactive effects of prey and p, p'-dde on burrowing owl population dynamics". 201930578717
evolution of genomic variation in the burrowing owl in response to recent colonization of urban areas.when a species successfully colonizes an urban habitat it can be expected that its population rapidly adapts to the new environment but also experiences demographic perturbations. it is, therefore, essential to gain an understanding of the population structure and the demographic history of the urban and neighbouring rural populations before studying adaptation at the genome level. here, we investigate populations of the burrowing owl (athene cunicularia), a species that colonized south american ...201829769357
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