6 resultados para White-matter Damage

em DigitalCommons@University of Nebraska - Lincoln


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White-tailed deer (Odocoileus virginianus) causing damage is a reoccurring theme in the realm of wildlife damage management, especially regarding human safety, disease transmission, and agricultural losses. Fences often are the only reliable long-term nonlethal means of controlling deer damage. The efficacy of fences, however, relies on their weakest link: human-operated gates. Although not overly time-consuming, the act of closing a gate appears to be a burden to individuals, resulting in open-access to an otherwise protected resource. We examined the efficacy of 2 alternatives to traditional gates to evaluate their potential to be used for excluding or containing deer. We evaluated a commercially available kit for mechanically opening and closing gates and a modified deer guard that resembles a common cattle guard but incorporates bearing-mounted rollers as cross members. The gate kit proved effective in restricting deer access to bait throughout the study, but, in supplemental evaluations, we observed excessive rates of functional failure. Deer guards reduced deer entry into exclosures, but efficacy declined with time as deer walked and jumped across guards. With some refining, both guards and gates have potential to be useful components of an integrated biosecurity strategy.

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In the past 50 years, the range of the nine-banded armadillo (Dasypus novemcinctus) in the south has been rapidly expanding. As their range expands, armadillos increasingly come into conflict with suburban landowners. When foraging, armadillos often uproot ornamental plants. Their rooting also destroys gardens, lawns, and flower beds. Their burrowing can damage tree roots and building foundations. Most armadillo damage is a result of their feeding habits. Armadillos dig shallow holes, 1- 3 inches deep and 3-5 inches long, as they search for soil invertebrates. A recent survey of Georgia county extension agents by scientists at the University of Georgia found that 77.6% of all agents reported receiving complaints or requests for information on armadillos. Armadillo related inquiries made up 10.1 % all inquiries for all agents across the state, surpassing even the white-tail deer (Odocoileus virginianus). Armadillos are often assumed to destroy nests of ground-nesting birds. Armadillo diets have been studied in several states including Alabama, Louisiana, Texas, Georgia, Arkansas, and Florida. According to these studies, vertebrate matter, especially bird eggs, made up an minor portion of their diet. The armadillo’s diet often consists of more than 90% insects, grubs and earthworms. Based on these studies, it seems that claims of armadillos being significant nest predators are unfounded.

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The State of Michigan is striving to eliminate bovine tuberculosis (Tb) infection among free-ranging white-tailed deer in the northeastern Lower Peninsula of the state. Aggressive reduction in the overall deer population abundance may help to further reduce TB prevalence, but this course of action is unacceptable to many hunters and landowners. Targeted culling of sick deer would likely be far more acceptable to these stakeholders, so in the winter of 2003 the Michigan Department of Natural Resources pilot-trialed a new strategy based on live-trapping and Tb-testing of wild deer. The field study was conducted in a township with relatively high TB prevalence within Deer Management Unit 452 in the northeastern Lower Peninsula. Over a 2-month trapping period, 119 individual deer were live-trapped, blood sampled, fitted with a radio-collar, and released. A total of 31 of these deer were subsequently classified as Tb-suspect by at least one of five blood tests employed (however there was a low level of agreement among tests). A delay in testing meant that only six of these suspect deer were culled by sharpshooters before pre-programmed release of their radio-collars, after which they could no longer be located. Mycobacterium bovis was cultured from one of these six suspect deer; the other five were negative on culture. All target deer were located to within shooting range with 1 – 2 days of effort, and all the radio-collars on the apparently-healthy deer dropped off after the intended 90-day interval, and were thereafter recovered for re-use. There was considerable support for this pilot project among hunters, farmers, state and federal agriculture agencies, the media and the general public, and so we recommend that further field trials be undertaken using this technique. The initial focus of these trials should be on improving the efficacy and reliability of the blood testing procedure.

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Herbivory assessments were conducted on seven reforested sites that were less than one year old in the following Mississippi counties: Bolivar, Leflore, and Attala. At each site, 100ft. x 100 ft. plots were established and randomly selected seedlings were marked and measured to determine seedling species, height, condition, survival, and type and extent of animal feeding sign. Surveys were conducted in March/April, May, and August 2004. Herbivory rates were highest during May with approximately 47% of seedlings showing signs of herbivory. In March/April and August, the percentage of seedlings exhibiting signs of herbivory was 37% and 30%, respectively. Foraging by white-tailed deer (Odocoileus virginianus) was recorded on > 90% of the damaged seedlings during each survey. Tree mortality for all study sites and tree species was negligible, with the highest amount (7%) recorded during August, despite the recorded rates of herbivory by white-tailed deer. Herbivory by rabbits (Sylvilagus spp.) and rodents occurred on approximately 6% of the seedlings throughout the 2004 growing season.

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We hypothesized that an exclusion fence could be devised to capitalize on traction limitations of the hooves of white-tailed deer (Odocoileus virginianus). Hexagonal plots (9.8 m wide) enclosed by a 2.4 m field fence with two openings (4.9 m) were established. Data were collected daily on consumption of corn provided (2.27 kg) and events recorded by infrared monitors (IR) for treatment and control sites. Five-day treatment periods consisted of test panels (4.9 m x 2.4 m) placed in plot openings at 0°, 5° and 10° slopes, and lubricant applied at the 10° slope. Deer consumed all corn provided at control sites. At the 10° slope, daily corn consumption decreased (1.50 kg ± 0.26, p < .01), and IR events were lower (p < .01) at treatment sites (23.6 ± 3.2) compared to controls (50.3 ± 9.6). With the addition of a lubricant, corn consumption decreased further (p < .001) to 0.17 kg ± 0.03, and IR recorded events were lower (p < .001) at treatment sites (6.58 ± 0.89) compared to controls (44.8 ± 3.1). Results of this study indicate that traction limitation of the hoof can be exploited.

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Each winter an estimated 350 million starlings, red-winged blackbirds (Agelaius phoeniceus), common grackles (Quiscalus quiscula), and brown-headed cowbirds (Molothrus ater) congregate in roosts in the southeastern United States (Meanley 1971, Meanley and Royall 1976). These birds have been of increasing concern because of agricultural damage claims (Stickley et al. 1976, Dolbeer et al. 1978), reputed health hazards (Monroe and Cronholm 1977), and other nuisance problems associated with them. Historical population trends (Dolbeer and Stehn 1979) and the source of winter-roosting blackbirds (Meanley 1971, Meanley and Dolbeer 1978, and Dolbeer 1978) have been summarized, but little information on the number of consecutive nights a bird returns to the same roost (roost fidelity) or the dynamics of a winter roost is available. The purpose of this paper is to present information on roost fidelity and population dynamics needed to better understand and manage winter blackbird and starling roosts.