No description available.

Objectives: The description of the raccoon rabies epizootic in Virginia over fifteen years (1989-2003). Methods: Using simple statistical methods and a geographic information system (GIS)-based approach, and fifteen years worth of animal surveillance data, the progress of this epizootic has been charted in terms of the geographic spread of the disease, the major animal species affected by the disease and its spread, and the exposure and risk to humans and livestock animals presented by the expansion of the geographic range. Results: The resulting descriptive study illustrates the eastward expansion of the epizootic, the mushrooming of the disease in the northern region of the state, and the rates of rabid animal submissions for every health district and selected important animal species. Human exposures to rabid animals are mapped and compared to human population densities. Strong seasonal trends in human and livestock exposures to rabid animals are illustrated, with animal exposures predominating in the spring and autumn, while human exposures peak in the summer; also shown is the possible emergence of new strains of rabies virus and the possible extinction of the previously dominant strain. Conclusions: Some potentially positive developments have been found, such as substantially increasing levels of bat submissions across time, which may signify greater public awareness of the disease. Serious deficiencies in the monitoring system are discussed, centering on the accuracy and comparability of the data collected, and suggestions for improvement are offered. While several potentially interesting new areas of study are put forward, the standard approach to rabies control (pet vaccination and control, education of at-risk populations, orally vaccinating wild animals) is not found to be in need of significant modification, aside from the specifics of the approach being tailored to better meet local conditions.

Early in the 20th century wild turkeys (Meleagris gallopavo) in North America were on the brink of extinction. Conservation and reintroduction efforts ensured that this species recovered throughout most of its historic range. Efforts to reintroduce eastern wild turkeys (Meleagris gallopavo sylvestris) to the Pineywoods of east Texas have achieved limited success. Previous research suggested that predation may have confounded this reintroduction. My aim was to quantify the influence of mesopredators on the wild turkey population in the Pineywoods. Raccoons (Procyon lotor), bobcats (Lynx rufus) and coyotes (Canis latrans) occur sympatrically in east Texas and are thought to prey on wild turkeys, their nests and poults. I fitted bobcats, coyotes and raccoons with both GPS and VHF collars and used location data and GIS applications to estimate home ranges, home range overlap and habitat selection for these mesopredators. I used scat analysis to determine diet of mesopredators and to establish whether they preyed on wild turkeys. I used capture mark recapture (CMR) techniques to investigate small mammal population dynamics at annual and seasonal bases. I used spotlight counts and track plates to assess seasonal relative abundance of eastern cottontail rabbits (Sylvilagus floridana). I used artificial nests to identify likely nest predators of wild turkey nests. I found that mesopredators in the Pineywoods had larger home ranges than elsewhere in the Southeast. Bobcat and coyote home ranges varied seasonally, being largest in fall. Raccoon home ranges did not vary seasonally. Bobcats and coyotes shared space more than did raccoons with bobcats or coyotes. There was differential habitat selection between species, but mature pine and young pine were important to the mesopredators and as nesting habitat for eastern wild turkeys. I found no evidence of wild turkey remains in scat samples. White tailed deer (Odocoileus virginianus), lagomorphs and small mammals occurred in the diets of all three mesopredators. Small mammal numbers varied seasonally, declining from spring to summer, in synchrony with mesopredator diet diversification, and wild turkey nesting and brood rearing. Lagomorph abundance did not vary seasonally. Bobcats were predominantly carnivorous while coyotes and raccoons were omnivorous, consuming seasonal fruit and insects. American crows (Corvus brachyrhynchos) and raccoons were the primary artificial nest predators. Crows depredated most artificial nests, except in summer, when raccoons depredated the most nests. I concluded that the impact of mesopredators on wild turkeys was not as severe as suggested by previous research. I suggest a combination of video monitoring live wild turkey nests to identify nest predators, improvement of nesting habitat to reduce mesopredator / wild turkey nest encounters, and a program of conditioned taste aversion to reduce any nest predation by mesopredators and crows.

Darbo tikslas: atlikti palyginamąją rudųjų lapių ir usūrinių šunų kaukolių, ilgųjų ir plokščiųjų galūnių kaulų osteologinę ir osteometrinę analizę. Darbo uždaviniai: 1. Išmatuoti ir palyginti usūrinių šunų ir rudųjų lapių patinų ir patelių kaukoles su apatiniais žandikauliais, krūminius dantis, plokščiuosius galūnių kaulus – mentę ir dubens kaulus ir ilguosius galūnių kaulus – petikaulį, dilbio kaulus, šlaunikaulį ir blauzdos kaulus. 2. Naudojantis gautais matmenimis atlikti tarprūšinį usūrinių šunų ir rudųjų lapių kaukolių su apatiniais žandikauliais, krūminių dantų, plokščiųjų galūnių kaulų – mentės ir dubens kaulų ir ilgųjų galūnių kaulų – petikaulio, dilbio kaulų, šlaunikaulio ir blauzdos kaulų palyginimą. 3. Apskaičiuoti kaukolių ir nurodytų ilgųjų galūnių kaulų – petikaulio, stipinkaulio, šlaunikaulio ir blauzdikaulio indeksus ir atlikti šių indeksų palyginimą tarp lyčių ir tarp tirtų gyvūnų rūšių. 4. Atlikti tarprūšinį kaukolių su apatiniais žandikauliais, plokščiųjų galūnių kaulų – mentės ir dubens kaulų, ilgųjų galūnių kaulų – petikaulio, dilbio kaulų, šlaunikaulio ir blauzdos kaulų morfologinį tyrimą palyginamosios anatomijos metodu. 5. Nustatyti tarprūšinius rudųjų lapių ir usūrinių šunų kaukolių vidinių struktūrų ir kaktikaulio ančių morfologinius ypatumus naudojant kompiuterinės tomografijos metodą. Pirmą kartą Lietuvoje atlikta palyginamoji usūrinių šunų ir rudųjų lapių kaukolių ir galūnių kaulų morfologinė analizė. Laukinės faunos osteologiniuose tyrimuose... [toliau žr. visą tekstą] / The aim of the present study is: to carry out a comparative osteological and osteometric analysis of skulls and long and flat bones of extremities of red foxes and raccoon dogs. The tasks include: 1. Measuring and comparison of the bones of male and female red foxes and raccoon dogs: skulls with jawbones, molars, the flat bones of extremities – scapula and pelvic bones – and the long bones of extremities – humerus, forearm, femur and crural bone. 2. Comparison of the bones of raccoon dogs and red foxes based on the obtained osteometric data about: skulls with jawbones, molars, the flat bones of extremities – scapula and pelvic bones – and the long bones of extremities – humerus, forearm bones, femur and crural bone. 3. Calculation of the indices of skulls and the indicated long bones of extremities – humerus, radius, femur and tibia – and comparison of these indices in the studied animals of different gender and species. 4. Morphological analysis of the bones – skulls with jawbones, the flat bones of extremities (scapula and pelvic bones) and the long bones of extremities (humerus, forearm, femur and crural bone) – of the studied species of animals by the method of comparative anatomy. 5. Determining the morphological features of the bones – internal structure of the skulls and frontal sinuses – of the studies species of animals (red foxes and raccoon dogs) by the method of computer tomography. The present work is a first attempt of comparative morphological analysis of the... [to full text]

SANTRAUKA Šio darbo tikslas – atlikti rudųjų lapių ir usūrinių šunų priekinės galūnės ilgųjų kaulų morfometrinę analizę. Pagal gautus duomenis nustatyti skirtumus esančius tarp rūšių ir lyčių. Tyrimui panaudoti LSMU Veterinarijos akademijos Anatomijos ir fiziologijos katedroje sukaupti 12 – os suaugusių usūrinių šunų ir rudųjų lapių ilgieji kaulai: iš jų usūrinių šunų – 6 (3 patelės, 3 patinai), rudųjų lapių – 6 (3 patelės, 3 patinai). Atsiţvelgiant į tai, kad nebuvo pastebėta esminių ilgio ir pločio skirtumų tarp kaitės ir dešinės pusės galūnių, buvo tiriamos tik kairės pusės galūnės. Tirtas petikaulis, dilbio kaulai (stipinkaulis ir alkūnkaulis), plaštakos kaulai. Kaulai išmatuoti pagal (Bisaillon A., De Roth L., 1979) metodiką, naudojant mechaninį slankmatį 0,01 mm tikslumu. Pagal gautus duomenis išmatuoti septyni kaulų indeksai. Išmatavus ir palyginus usūrinių šunų ir rudųjų lapių patinų ir patelių ilguosius kaulus nustatyta, kad lapių patinų petikaulis, dilbio ir plaštakos kaulai ilgesni nei lapių patelių. Tarp kaulų pločio reikšmingų skirtumų nebuvo aptikta. Usūrinių šunų patinų petikaulis ir stipinkaulis ilgesnis nei usūrinių šunų patelių. Usūrinių šunų patelių alkūnkaulis ilgesnis nei usūrinių šunų patinų. Plaštakos kaulų ilgis ir plotis skyrėsi neţymiai. Palyginus tarprūšiniu poţiūriu, lapių patinų ilgieji kaulai ilgesni nei usūrinių šunų patinų. Tarp kaulų pločio esminių skirtumų nebuvo. Lapių patelių petikaulis ir dilbio kaulai ilgesni nei usūrinių šunų patelių... [toliau žr. visą tekstą] / SUMMARY Aim of this work – to perform morphometric analysis of the long bones of the foreleg of raccoon dogs and red foxes. To determine the differences between the sorts and sexes according to the data got. Long bones of 12 adult raccoon dogs and red foxes, kept at the Department of Anatomy and Physiology of Academy of Veterinary of Lithuanian University of Health Sciences, have been analysed: 6 – of raccoon dogs (3 females, 3 males), 6 – of red foxes (3 females, 3 males). Humerus, forearm bones (radius and ulna), and metacarpal bones have been investigated. Bones have been measured according to (Bisaillon A., De Roth L., 1979) method, using mechanical calliper (precision of 0.1 mm). Seven indexes of the bones have been measured according to the data got. When the long bones of female and male raccoon dogs and red foxes have been measured and compared, it has been determined that humerus, forearm and metacarpal bones of the male foxes are longer compared to the female foxes. Significant differences of the bone width have not been determined. Humerus and radius of the male raccoon dogs are longer compared to the female raccoon dogs. Ulna of the female raccoon dogs is longer compared to the male raccoon dogs. Length and width of the metacarpal bones were different marginally. When compared according to the interspecific point of view, long bones of the male foxes are longer than bones of the raccoon dogs. There were no essential differences between widths of the bones... [to full text]

Egg predation may be the most important mortality factor for North American turtles. This predation can destroy 50-90% of nests in an area. The major predators are striped skunks (Mephitis mephitis) and raccoons (Procyon lotor). Despite differences in their habits and diet, these species appear equally efficient in turtle egg predation, even though these eggs represent a very small portion of their annual food intake. Sight, olfaction, touch and hearing could be used by these predators to find the nests. The aim of this study was to document intra and inter-specific differences in the perception of possible nest-cues used by raccoon and striped skunk. Choice-tests based on food-conditioning were carried out with two visual cues (dark and smooth surface), one olfactory cue (turtle urine) and one tactile cue (soil compaction). Subject performances (number of trials to obtain 80% success rate in the different tests) were compared to assess intra and inter-species, and skunk inter-age differences in sensory perception and learning abilities. As expected raccoons learned the tactile cue discrimination faster than the visual cue discriminations. The tactile cue discrimination was learned as fast as the olfactory cue. As expected skunks learned the olfactory cue discrimination faster than other cue discriminations. When compared, the olfactory cue appeared to be as important for both species even though raccoons had faster learning rates than skunks in all the tests except for one visual test. Juvenile skunks learned faster than adult skunks with four out of six juveniles performing better in the olfactory test. Olfaction may play an important role in nest localization by raccoons and skunks, and sight may also play a role for raccoons. Learning turtle nest cues while with their mother could facilitate their future ability in locating turtle nests.

No description available.

No description available.

Mounting evidence suggests that large carnivores regulate the abundance and diversity of species at multiple trophic levels through cascading top-down effects. The fear large carnivores inspire in their prey may be a critical component of these top-down effects, buffering lower trophic levels from overconsumption by suppressing large herbivore and mesopredator foraging. However, the evidence that the fear of large carnivores cascades through food webs has been repeatedly challenged because it remains experimentally untested. My collaborators and I exploited a natural experiment – the presence or absence of mesopredator raccoons (Procyon lotor) on islands in the Gulf Islands of British Columbia, Canada – to examine the breadth of mesopredator impacts in a system from which all native large carnivores have been extirpated. By comparing prey abundance on islands with and without raccoons, we found significant negative effects of raccoon presence on terrestrial (songbirds and corvids), intertidal (crabs and fish) and shallow subtidal (red rock crabs Cancer productus) prey, demonstrating that, in the absence of native large carnivores, mesopredator impacts on islands can extend across ecosystem boundaries to affect both terrestrial and marine communities. To test whether fear of large carnivores can mitigate these community-level impacts of mesopredators, we experimentally manipulated fear in free-living raccoon populations using month-long playbacks of large carnivore vocalizations and monitored the effects on raccoon behaviour and the intertidal community. Fear of large carnivores reduced raccoon foraging to the benefit of the raccoon’s prey, which in turn affected a competitor and prey of the raccoon’s prey. By experimentally restoring the fear of large carnivores in our study system, we succeeded in reversing the impacts of raccoons, reinforcing the need to protect large carnivores given the conservation benefits the fear of them provides. Our experimental work demonstrated that fine-scale behavioural changes in prey in response to predation risk can have community-level effects relevant to biodiversity conservation. However, experimentally testing animal responses to predators and other sources of risk in free-living wildlife presents considerable logistical challenges. To address these challenges, my collaborators and I developed an Automated Behavioural Response system, which integrates playback experiments into camera trap studies, allowing researchers to collect experimental data from wildlife populations without requiring the presence of an observer. Here I describe tests of this system in Uganda, Canada and the USA, and discuss novel research opportunities in ecology and conservation biology made available by this new technology. / Graduate

No description available.