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ABSTRACT: Movements of male white-tailed deer (Odocoileus virginianus) are of great concern with respect to spread of chronic wasting disease (CWD) across landscapes because most yearlings males disperse and adult males have higher prevalence of CWD than do females and younger deer. We radiocollared and monitored 85 male white-tailed deer in the middle Missouri River Valley of eastern Nebraska and western Iowa, USA from 2004 to 2008. Average size (±SE) of fixed-kernel annual home ranges (95%) and core areas (50%) for resident deer were 449 (±32) ha and 99 (±7) ha, respectively. Resident deer exhibited a high-degree of fidelity to their home ranges. Mean overlap between consecutive annual home ranges and core areas was 81% and 74%, respectively. Average dispersal distance was 17.7 ± 4.5 km (range = 3–121 km) for 22 radio-marked and 6 ear-tagged yearlings. Mean spring dispersal distance (25 km) was 150% greater than fall (10 km). Dispersal direction from Desoto National Wildlife Refuge (DNWR) was bimodal on a northwest to southeast axis that followed the Missouri River corridor. Of 22 yearlings that dispersed, 18 (82%) established adult home ranges within the river valley. Dispersal movements of yearling males represent the greatest risk for rapid spread of diseases from infected source populations. Disease management efforts in riparian habitats should target male fawns and yearling males for removal in areas within or immediately adjacent to river corridors. © 2011 The Wildlife Society.
Journal of Wildlife Management 07/2011; 75(6):1436 - 1442. · 1.52 Impact Factor
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ABSTRACT: Over-abundant populations of white-tailed deer (Odocoileus virginianus) create agricultural and human health and safety issues. The increased economic damage associated with locally overabundant deer populations accentuates the need for efficient techniques to mitigate the losses. Although red lasers can be an efficient tool for reducing damage caused by birds, they are not effective for deer because deer cannot detect wavelengths in the red portion of the spectrum. No research has been conducted to determine if lasers of lower wavelengths could function as frightening devices for deer. We evaluated a green laser (534 nm, 120 mW) and 2 models of blue lasers (473 nm, 5 mW and 15 mW) to determine their efficacy in dispersing deer at night. Deer were no more likely to flee during a green or blue laser encounter than during control encounters. The green and blue lasers we tested did not frighten deer.
Wildlife Society Bulletin 01/2009; · 0.95 Impact Factor
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ABSTRACT: Deer (Odocoileus spp.) can cause substantial damage to agricultural crops, resulting in economic losses for producers. We developed a deer-activated bio-acoustic frightening device to reduce white-tailed deer (O. virginianus) damage in agricultural fields. The device consisted of an infrared detection system that activated an audio component which broadcast recorded distress and alarm calls of deer. We tested the device against unprotected controls in cornfields during the silking-tasseling stage of growth in July 2001. The device was not effective in reducing damage: track-count indices (F1,4=0.02, P=0.892), corn yield (F1,9=1.27, P=0.289), and estimated damage levels (F1,10=0.87, P=0.374) did not differ between experimental and control fields. The size (F2,26=1.00, P=0.380), location (F2,25=0.39, P=0.684), and percent overlap (F2,25=0.20, P=0.818) of use-areas of radiomarked female deer did not differ between during- and after-treatment periods. We concluded that the deer-activated bio-acoustic device was not effective in protecting cornfields in this study; however, the device may be more effective in small areas such as gardens or for high-value crops that do not grow tall enough to offer protective cover.
Wildlife Society Bulletin 05/2004; 32(2):515 - 523. · 0.95 Impact Factor
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ABSTRACT: Wildlife is often responsible for causing extensive damage to personal property, human health and safety concerns, and other nuisance problems because of their feeding, roosting, breeding, and loafing habits. Frightening devices are tools used in integrated wildlife damage management to reduce the impacts of animals, but the effectiveness of such devices is often variable. An animal''s visual and auditory capabilities affect how the animal will respond to a stimulus. Frightening devices include pyrotechnics, gas exploders, effigies, lights, lasers, reflective objects, guard animals, bioacoustics, and ultrasonic devices. We examined scientific literature on the use of frightening devices to reduce bird and mammal depredation and compiled results to determine the effectiveness of such devices. When used in an integrated system, frightening devices may be more effective than when used alone. We conclude that the total elimination of damage may be impossible, but frightening devices and/or combinations of devices are useful in reducing wildlife damage. Ultrasonic frightening devices are ineffective in repelling birds and mammals whereas other devices offer some protection. The timely use of a variety of frightening devices can be part of a cost-effective integrated system to reduce wildlife damage to tolerable levels.
Integrated Pest Management Reviews 02/2002; 7(1):29-45.
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ABSTRACT: Deer (Odocoileus spp.) can cause substantial damage to agricultural crops, resulting in economic losses for producers. We developed a deer-activated bio-acoustic frightening device to reduce white-tailed deer (O. virginianus) damage in agricultural fields. The device consisted of an infrared detection system that activated an audio component which broadcast recorded distress and alarm calls of deer. We tested the device against unprotected controls in cornfields during the silking-tasseling stage of growth in July 2001. The device was not effective in reducing damage: track-count indices (F1,4=0.02, P=0.892), corn yield (F1,9=1.27, P=0.289), and estimated damage levels (F1,10=0.87, P=0.374) did not differ between experimental and control fields. The size (F2,26=1.00, P=0.380), location (F2,25 =0.39, P =0.684), and percent overlap (F2,25 =0.20, P =0.818) of use-areas of radiomarked female deer did not differ between during- and after-treatment periods. We concluded that the deer-activated bio-acoustic device was not effective in protecting cornfields in this study; however, the device may be more effective in small areas such as gardens or for high-value crops that do not grow tall enough to offer protective cover.
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ABSTRACT: White-tailed deer (Odocoileus virginianus) cause millions of dollars of damage to agricultural crops annually. We tested the effectiveness of propane exploders and Electronic Guards (Pocatello Supply Depot, Pocatello, Id.) for reducing deer damage in cornfields during the silking-tasseling stage of growth. Track-count indices (F2,7=0.70, P=0.532), corn yields (F2,6=0.14, P=0.873), and estimated damage levels (F2,12=1.45 P=0.272) did not differ between experimental and control fields. The size (F2,11=0.08, P=0.924), location (F2,9 =0.30, P =0.750), and percent overlap (F2,9 =0.46, P =0.644) of use-areas of radiomarked female deer in the vicinity of experimental fields did not differ among before, during, and after 18-day treatment periods. In a related study, we placed propane exploders in cornfields within use-areas of 12 radiomarked female deer. The deer did not react appreciably to the devices: the size (F2,17=0.08, P=0.921), location (F2,22=1.37, P = 0.275), and percent overlap (F2,10 = 0.47, P = 0.636) of deer use-areas did not differ among before, during, and after 14-day treatment periods. We conclude that propane exploders and Electronic Guards have limited potential for reducing deer damage to corn at the silking-tasseling stage.
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ABSTRACT: The expansion of the cellulosic biofuels industry throughout the United States has broad-scale implications for wildlife management on public and private lands. Knowledge is limited on the effects of reverting agriculture to native grass, and vice versa, on size of home range and habitat use of white-tailed deer (Odocoileus virginianus). We followed 68 radiocollared female deer from 1991 through 2004 that were residents of DeSoto National Wildlife Refuge (DNWR) in eastern Nebraska, USA. The refuge was undergoing conversion of vegetation out of row-crop agriculture and into native grass, forest, and emergent aquatic vegetation. Habitat in DNWR consisted of 30% crop in 1991 but removing crops to establish native grass and wetland habitat at DNWR resulted in a 44% reduction in crops by 2004. A decrease in the amount of crops on DNWR contributed to a decline in mean size of annual home range from 400 ha in 1991 to 200 ha in 2005 but percentage of crops in home ranges increased from 21% to 29%. Mean overlap for individuals was 77% between consecutive annual home ranges across 8 years, regardless of crop availability. Conversion of crop to native habitat will not likely result in home range abandonment but may impact disease transmission by increasing rates of contact between deer social groups that occupy adjacent areas. Future research on condition indices or changes in population parameters (e.g., recruitment) could be incorporated into the study design to assess impacts of habitat conversion for biofuel production.
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ABSTRACT: Movements of deer can affect population dynamics, spatial redistribution, and transmission and spread of diseases. Our goal was to model the movement of deer in Nebraska in an attempt to predict the potential for spread of chronic wasting disease (CWD) into eastern Nebraska. We collared and radio-tracked >600 white-tailed deer (Odocoileus virginianus) and mule deer (Odocoileus hemionus) in Nebraska during 1990-2006. We observed large displacements (>10 km) for both species and sexes of deer, including migrations up to 100 km and dispersals up to 50 km. Average distance traveled between successive daily locations was 166 m for male and 173 for female deer in eastern Nebraska, and 427 m for male and 459 for female deer in western Nebraska. Average daily displacement from initial capture point was 10 m for male and 14 m for female deer in eastern Nebraska, and 27 m for male and 28 m for female deer in western Nebraska. We used these data on naturally occurring movements to create and test 6 individual-based models of movement for white-tailed deer and mule deer in Nebraska, including models that incorporated sampling from empirical distributions of movement lengths and turn angles (DIST), correlated random walks (CRW), home point fidelity (FOCUS), shifting home point (SHIFT), probabilistic movement acceptance (MOVE), and probabilistic movement with emigration (MOVEwEMI). We created models in sequence in an attempt to account for the shortcomings of the previous model(s). We used the Kolmogrov-Smirnov goodness-of-fit test to verify improvement of simulated annual displacement distributions to empirical displacement distributions. The best-fit model (D = 0.07 and 0.08 for eastern and western Nebraska, respectively) included a probabilistic movement chance with emigration (MOVEwEMI) and resulted in an optimal daily movement length of 350 m (maximum daily movement length of 2800 m for emigrators) for eastern Nebraska and 370 m (maximum of 2960 m) for western Nebraska. The proportion of deer that moved as emigrators was 0.10 and 0.13 for eastern and western Nebraska, respectively. We propose that the observed spread of CWD may be driven by large movements of a small proportion of deer that help to establish a low prevalence of the disease in areas east of the current endemic area. Our movement models will be used in a larger individual-based simulation of movement, survival, and transmission of CWD to help determine future surveillance and management actions.
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ABSTRACT: Nontimber forest products (food, herbal medicinals, and woody floral and handicraft products) produced in forest, agroforestry, and horticultural systems can be important sources of income to landowners. White-tailed deer (Odocoileus virginianus) can reduce the quality, quantity, and profitability of forest products by browsing twigs and rubbing stems, resulting in direct and indirect losses to production enterprises. We evaluated deer damage (frequency and intensity of browsing and rubbing) sustained by 26 species of trees and shrubs, the relationships among morphological features of trees and shrubs to damage levels, and the economic impacts of deer damage on the production of nontimber forest products. Levels of browsing were high (frequency >93% and intensity >50%) in most species of trees and shrubs, with the highest intensity (>60%) occurring in chinese chestnut (Castanea mollisima) and dogwood (Cornus spp.), and the lowest (<20%) in ginkgo (Ginkgo biloba), curly willow (Salix matsudana), 'Scarlet Curls' curly willow, smooth sumac (Rhus glabra), and pussy willow (Salix caprea). Species of trees or shrubs with one or a few stout stems unprotected by dense branching [e.g., american elderberry (Sambucus canadensis), smooth sumac, and curly willow] sustained the most damage by rubbing. Trees and shrubs with many small diameter stems or with dense tangled branching [e.g. redozier dogwood (Cornus sericea), forsythia (Forsythia suspensa), 'Flame' willow (Salix alba), and 'Streamco' basket willow (Salix purpurea)] were damaged the least by rubbing. Annual economic costs of deer damage to producers of nontimber forest products can range from $26/acre for pussy willow to $1595/acre for curly willow.
