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# Infrared-triggered cameras for censusing white-tailed deer

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Deer management often is hindered by lack of public acceptance and confidence in census methods. Because 'seeing is believing,' a method relying on photographic documentation could provide a powerful tool for deer managers. The purpose of our study was to determine if infrared-triggered cameras could be used for population estimation of free-ranging antlered white-tailed deer (Odocoileus virginianus) in a forested environment. Subsequently, we evaluated feasibility of using such estimates in conjunction with demographic ratios for population estimation. We used infrared-triggered cameras and monitors to census white-tailed deer on Longleaf Farms, a 4,047-ha area in Amite County, Mississippi. Two 14-day censuses were conducted, 1 in February 1992 and 1 in February 1993. Passive infrared monitors that triggered automatic cameras were used to photograph deer; previously marked deer in the photographs provided recapture data. We derived population estimates from photographs using Lincoln-Petersen Index estimates from marked and unmarked animals, and from a separate technique we termed the camera estimate. The camera estimate was calculated by determining the total numbers of branch-antlered bucks, spike bucks, does, and fawns in photographs, then determining the number of individually identifiable branch-antlered bucks and, from ratios, the number of spike bucks, does, and fawns. Camera densities tested included 65, 130, and 259 ha per camera. With the highest camera density (1/65 ha), 30 of 30 collared deer (100%) were recaptured in 1992 and 30 of 34 (88.2%) were recaptured in 1993. Camera estimates using ratios of spikes, does, and fawns to branch-antlered bucks yielded population estimates of 715, and 580 deer for 1992 and 1993, respectively. Lincoln-Petersen estimates yielded 727 and 573 deer for the same respective periods. However, at different camera densities, the sex ratios and Lincoln-Petersen Index population estimates differed significantly (P≤ 0.001). There was an inverse relationship between camera density and Lincoln-Petersen Index population estimates. Percent females increased as camera density increased, indicating higher recapture estimates of males over females at low camera densities. Although population and sex-ratio estimates differed among camera-station densities, infrared-triggered cameras are useful tools to census deer in forested environments. Minimally, they provide estimates of adult bucks present. Cost of a 14-day census amortized over a 5-year equipment life expectancy ranged 0.37-1.29/ha/year depending on camera coverage. ## No full-text available ... Camera surveys can be less labor intensive, less invasive (Cutler andSwann 1999, Rowcliffe et al. 2008), and less limited by thick vegetation, weather, or observer bias (Larrucea et al. 2007, Rowcliffe et al. 2008 compared to other survey methods. Jacobson et al. (1997) developed a survey method (hereafter, Jacobson method) to estimate Deer population size by enumerating the photographic rate of adult males using uniquely identifiable antler characteristics and extrapolating that ratio to the remaining population. The Jacobson method has been criticized for failure to generate measures of precision (Curtis et al. 2009) and the assumption, which may not be met, of equal detectability among age and sex classes (McCoy et al. 2011, Moore et al. 2014. ... ... We established camera sites in accordance to Jacobson et al. (1997). We divided the study area into square 100-ha grid cells ( Fig. 1) and placed a Reconyx HC600 infrared camera (n = 20; Reconyx Inc., Holmen, WI) at the center; however, we adjusted exact placement to provide ease of access and increase likelihood of visitation by Deer . ... ... With the Jacobson camera method, the assumption of equal detectability is essential to density estimates and is based on detection probability of individually identifiable males. Jacobson et al. (1997) stated that bias by gender would bias estimates of Deer populations. Past research has documented such gender-specific bias of camera surveys (Cutler and Swann 1999, Larrucea et al. 2007, Moore et al. 2014. ... Article The enumeration of Odocoileus virginianus (White-tailed Deer, hereafter, Deer) populations is an important objective for many managers, but no consensus regarding the most appropriate scientific methodology exists. Extensive research has been conducted involving comparisons of multiple methods to evaluate the effectiveness of estimating demographics of free-ranging populations; however, most fail to account for spatial or temporal differences in their comparisons. We estimated the density of an open population of Deer on a strict concurrent spatial and temporal scale during 3 separate 14-day periods (August 2012, February 2013, August 2013) using 4 methods: road-based distance sampling using spotlight surveys, FLIR surveys, and camera surveys using both the Jacobson analysis method or an N-mixture model abundance analysis. Spotlight surveys were affordable but required substantial effort to achieve the precision necessary for management decisions. FLIR surveys had greater detection probabilities relative to spotlight surveys and required less effort to achieve sufficient precision. Jacobson camera surveys appeared to overestimate Deer density and provided no measures of precision. The N-mixture model camera surveys provided sufficient precision and generated point estimate and detection probabilities similar to FLIR surveys. Camera surveys were costlier and more labor intensive relative to road-based surveys. We recommend road-based distance sampling using FLIR technology to estimate Deer density, but managers should understand the limitations and biases associated with any density estimate before incorporating the results into a management program. ... able and cost-effective tools for population monitoring (Jenkins and Marchinton 1969, Jacobson et al. 1997, Heilbrun et al. 2006, McKinley et al. 2006. Techniques that not only estimate density (Lancia et al. 1994) but also allow detection of changes in density over time are needed (Gibbs 2000, Murray and Fuller 2000, Peterson et al. 2003. ... ... Remote photography surveys have a long history in wildlife research and have surged in popularity since the advancement and commercialization of infrared-triggered camera (hereafter; camera) systems (Jacobson et al. 1997, Cutler and Swann 1999, Koerth and Kroll 2000. Camera surveys have been used for population estimation of many wildlife species and are popular among land managers for deer population monitoring (Jacobson et al. 1997, Koerth and Kroll 2000, Heilbrun et al. 2006, Rowcliffe et al. 2008. ... ... Remote photography surveys have a long history in wildlife research and have surged in popularity since the advancement and commercialization of infrared-triggered camera (hereafter; camera) systems (Jacobson et al. 1997, Cutler and Swann 1999, Koerth and Kroll 2000. Camera surveys have been used for population estimation of many wildlife species and are popular among land managers for deer population monitoring (Jacobson et al. 1997, Koerth and Kroll 2000, Heilbrun et al. 2006, Rowcliffe et al. 2008. Camera surveys can be cost-effective (Kucera andBarrett 1993, Rowcliffe et al. 2008), less invasive (Franzreb and Hanula 1995, van Schaik and Griffiths 1996, Cutler and Swann 1999, Rowcliffe et al. 2008, and less labor intensive (Seydack 1984, Cutler and Swann 1999, Rowcliffe et al. 2008) compared with other techniques, such as direct observations or live-capture studies (Cutler andSwann 1999, Larrucea et al. 2007). ... Article Full-text available Population monitoring of wildlife species requires techniques that produce estimates with low bias and adequate precision. Use of infrared-triggered camera (hereafter; camera) surveys for white-tailed deer (Odocoileus virginianus; deer) population density estimation is popular among land managers. However, current camera surveys do not provide an estimate of precision critical for accurate density estimation. We believed that incorporating spatial aspects of sampling into the analytical process would allow for both estimates of precision associated with density and an ability to calculate effective sample area. We conducted camera surveys for deer in Units 1 (1,385 ha) and 2 (1,488 ha) at Arnold Air Force Base, Tennessee, in August 2010. We used 1 camera per 53 and 62 ha in Units 1 and 2, respectively, and identified individual male deer based on antler criteria. We used spatially explicit capture-recapture (SECR) data with Program DENSITY to fit a spatial detection function (g0; probability of detecting an individual on a single occasion when the distance between their home range center and a trap is zero) and sigma (the scale parameter that determines the rate at which detection probability decreases with distance between a home range center and a trap) to estimate antlered male density. Density estimates were similar between camera surveys (based on recaptures of recognizable antlered males from camera images) using traditional sampling techniques (without spatial information on capture) and spatially explicit density estimation (with a record of location for each individual camera capture). Antlered male density estimates obtained via traditional sampling for Units 1 and 2 were 2.0 and 2.6 males/km2, respectively. Density estimates based on SECR models were 1.6 males/km2 (SE = 0.33, g0 = 0.24) for Unit 1 and 2.5 males/km2 (SE = 0.56, g0 = 0.14) for Unit 2. Both estimation methods indicated lower deer density in Unit 1 versus Unit 2. Analysis of camera surveys using SECR modeling uses the data from the spatial distribution of cameras and does not require the assumption of equal detectability. Use of SECR modeling can improve current camera survey methods by providing both a measure of precision that is currently lacking from traditional camera analysis methods and including spatial distribution of captured deer. Spatial modeling should be explored further to enhance our understanding of potential biases associated with behavioral responses to the use of bait as an attractant. ... Regarding cervids, some Neotropical species possess branched antlers (Odocoileus, Blastocerus, Ozotoceros and Hippocamelus), thus distinct morphology can be used for individual identification. One example is the pioneering study by Jacobson et al. (1997), who conducted population surveys of white-tailed deer [Odocoileus virginianus (Zimmermann, 1780)] using camera traps. This protocol has been used to estimate cervid populations from camera traps, together with the capturemark-recapture method (DeYoung, 2011). ... ... Estimating the population parameters (density, sex ratio and age proportions) was based on the work of Jacobson et al. (1997), who used capture-mark-recapture models to estimate the number of branch-antlered males and extrapolated this data to the rest of the population based on the proportions of the remaining groups in the records. For this purpose, the population was divided into four groups in accordance with Jacobson et al. (1997)'s subdivisions: branch-antlered males, spike-antlered bucks, females and fawns. ... ... Estimating the population parameters (density, sex ratio and age proportions) was based on the work of Jacobson et al. (1997), who used capture-mark-recapture models to estimate the number of branch-antlered males and extrapolated this data to the rest of the population based on the proportions of the remaining groups in the records. For this purpose, the population was divided into four groups in accordance with Jacobson et al. (1997)'s subdivisions: branch-antlered males, spike-antlered bucks, females and fawns. The branch-antlered males class refers to males with at least two tines on each side of the antler rack. ... Article Full-text available Demographic information is the basis for evaluating and planning conservation strategies for an endangered species. However, in numerous situations there are methodological or financial limitations to obtain such information for some species. The marsh deer, an endangered Neotropical cervid, is a challenging species to obtain biological information. To help achieve such aims, the study evaluated the applicability of camera traps to obtain demographic information on the marsh deer compared to the traditional aerial census method. Fourteen camera traps were installed for three months on the Capão da Cruz floodplain, in state of São Paulo, and ten helicopter flyovers were made along a 13-kilometer trajectory to detect resident marsh deer. In addition to counting deer, the study aimed to identify the sex, age group and individual identification of the antlered males recorded. Population estimates were performed using the capture-mark-recapture method with the camera trap data and by the distance sampling method for aerial observation data. The costs and field efforts expended for both methodologies were calculated and compared. Twenty independent photographic records and 42 sightings were obtained and generated estimates of 0.98 and 1.06 ind/km², respectively. In contrast to the aerial census, camera traps allowed us to individually identify branch-antlered males, determine the sex ratio and detect fawns in the population. The cost of camera traps was 78% lower but required 20 times more field effort. Our analysis indicates that camera traps present a superior cost-benefit ratio compared to aerial surveys, since they are more informative, cheaper and offer simpler logistics. Their application extends the possibilities of studying a greater number of populations in a long-term monitoring. ... Hunters are not likely to participate in management efforts without evidence of tangible results (Cooney and Holsman 2010), and the belief that aggressive population reduction will prevent hunters from observing or harvesting deer in the future is likely to result in distrust of wildlife professionals and a decline in hunter participation (Van Deelen andEtter 2003, Vaske et al. 2004 vCJD and CWD has been found, however the risk cannot be dismissed with absolute certainty (Raymond et al. 2000, Belay et al. 2004). Significant declines in hunter participation has several adverse effects on a typical CWD management strategy, including loss of revenue generated by license sales (Miller and Vaske 2003) and an increase in deer densities that may facilitate disease spread and compromise management goals (Enck 1996 CWD infected states has shown a small but significant decline in hunter participation after disease emergence (Bishop 2004, Heberlein 2004, with a more precipitous drop likely as prevalence increases (Gigliotti 2004, Needham et al. 2004 Several methods are used to obtain deer abundance estimates including, but not limited to, spotlight surveys (Progulske and Duerre 1964), thermal-imaging surveys (Wiggers and Beckerman 1993), motion-triggered cameras surveys (Jacobson et al. 1997), and mark-recapture studies (McCullough and Hirth 1988). Each method, however, is subject to unique biases that may produce estimates that do not reflect true dynamics of the populations of interest (McKinely et al. 2006;Roberts et al. 2006;Collier et al. 2007Collier et al. , 2013McCoy et al. 2011). ... ... An overabundance of deer can be detrimental however; degrading forest communities (Tilghman 1989, Russel et al. 2001, Rossell et al. 2005, causing significant economic losses and damage to personal property (Conover et al. 1995, Romin and Bissonette 1996, Bissonette et al. 2008, and facilitating the spread of diseases such as Lyme disease (Rand et al. 2003) and Chronic Wasting Disease (Williams et al. 2002, Kjaer et al. 2008. A means for estimating deer demographic information as well as monitoring population trends over time is a necessary tool for sound deer management (Jacobson et al. 1997, Gibbs 2000. Such tools, however, are often limited by accuracy, reliability, and cost (Jenkins and Marchington 1969). ... ... Several methods for obtaining abundance and demographic estimates exist, but each is subject to biases and limitations that hinder reliability. Pellet counts (Eberhardt andVan Etten 1956, Neff 1968), spotlight surveys (Progulske andDuerre 1964, McCullough 1982), aerial counts (Caughley 1977, Potvin et al. 2002, mark-recapture studies (McCullough and Hirth 1988), herd reconstruction from harvest data (Roseberry andWolf 1991, Millspaugh et al. 2009) and motion-triggered camera surveys (Jacobson et al. 1997, Koerth andKroll 2000) are methods commonly used to generate estimates, but vary in efficiency and cost. ... Thesis Full-text available Chronic Wasting Disease (CWD) is a fatal neurological disease of North American deer species which has emerged as an important wildlife management issue. In 2010, a hunter harvested deer in Allegany County, Maryland tested positive for the disease. Herein, I examine 2 important aspects of CWD management in the state of Maryland. The first objective was to determine the impact of human dimensions, specifically negative hunter attitude towards CWD and restrictive management regulations, on deer harvest throughout the state. I used an attitude study completed by Responsive Management (Harrisonburg, VA) to identify hunters in 3 counties (Allegany, Garrett, and Dorchester) of varying proximity to the disease. Hunters were asked if and how CWD had caused them to alter their harvest behavior. I then linked each individual’s response to their harvest history to determine the degree to which negative hunter attitude had reduced deer harvest. The amount of hunters who claimed to have changed their behavior due to CWD ranged from 14.08% in Dorchester County to 22.63% in Allegany County, suggesting distance to the disease affected attitude. In Allegany County, CWD caused a 6.95% average decrease in the annual harvest, which falls well within the normal stochastic variability in annual harvest. I observed no reduction in deer harvest attributable to CWD in Garrett or Dorchester Counties. My findings suggest that reduction in deer harvest after the discovery of CWD due to negative hunter attitude is highly localized near the disease management area and has little impact on deer management. My second objective was to evaluate 3 common methods (spotlight and thermal-imaging road-based distance sampling and motion-triggered camera surveys) for estimating deer density and demographic parameters. I performed all 3 methods concurrently during 2 week sampling periods. Sampling periods occurred in August 2012, February 2013, and August 2013. Methodology comparison incorporated point estimates, measures of precision, detection probability, and cost. Camera surveys appeared to overestimate deer density, provided no measures of precision, and had a higher cost than road-based surveys. Spotlight surveys were affordable but required substantial effort to achieve the precision necessary for management decisions. Thermal-imaging surveys had greater detection probabilities relative to spotlight surveys and required less effort to achieve sufficient precision. I recommend road-based distance sampling incorporating thermal-imaging technology to estimate deer demographic parameters at the disease management unit scale. ... Baiting is frequently used to alter behavior of wildlife for desirable outcomes such as increasing harvest success, facilitating population control [1][2][3][4], enhancing wildlife viewing opportunities, increasing detection rates for camera surveys [5,6], and improving capture rates in research efforts [7,8]. However, baiting wildlife can produce undesirable outcomes such as trophic cascades [9], inter-and intra-specific competition [10,11], and increased risk of disease transmission [12][13][14][15]. ... ... Therefore, we used the pre-established 29 baited camera locations for this property (one camera per approximately 50 ha) and placed 49 passive cameras (one camera per approximately 20 ha) within the baited camera array. Baited cameras were operated and distributed according to the methodology commonly associated with a camera survey using bait [5]. Unlike the other properties, the majority of baited camera locations on property one were associated with long-term tripod gravity feeders, containing corn or protein pellet supplements; however, feeders remained empty while the baited camera surveys were conducted. ... ... Therefore, we used the pre-established 29 We secured baited cameras on trees~1.5 m from ground level near the center of each grid cell and placed shelled corn approximately 5 m from each baited camera. Baited cameras were operated for two weeks after a one-wk pre-baiting period [5]. We placed the passive cameras within 200 m of the centroid of each grid cell, on trees or metal fence posts at the same height as baited cameras. ... Article Full-text available Bait is often used to increase wildlife harvest susceptibility, enhance viewing opportunities, and survey wildlife populations. The effects of baiting depend on how bait influences space use and resource selection at multiple spatial scales. Although telemetry studies allow for inferences about resource selection within home ranges (third-order selection), they provide limited information about spatial variation in density, which is the result of second-order selection. Recent advances in spatial capture-recapture (SCR) techniques allow exploration of second- and third-order selection simultaneously using non-invasive methods such as camera traps. Our objectives were to describe how short-term baiting affects white-tailed deer (Odocoileus virginianus) behavior and distribution. We fit SCR models to camera data from baited and unbaited locations in southwestern Georgia to assess the effects of short-term baiting on second- and third-order selection of deer during summer and winter surveys. We found little evidence of second-order selection during late summer or early winter surveys when camera surveys using bait are typically conducted. However, we found evidence for third-order selection, indicating that resource selection within home ranges is affected. Concentrations in space use resulting from baiting may enhance disease transmission, change harvest susceptibility, and potentially bias the outcome of camera surveys using bait. ... Automated cameras have been used to monitor wildlife in a variety of habitat types (Curtis et al. 2009;Jacobson et al. 1997;Koerth et al. 1997), and there are various options available for design and analysis of camera survey data. Burton et al. (2015) reviewed over 250 camera trap studies published from 2008 to 2013 and found that the majority estimated density of marked individuals. ... ... Although some methods exist for estimating abundance or density of unmarked populations, many camera trap studies on unmarked populations estimate relative abundance and assume equal detectability (Burton et al. 2015). Jacobson et al. (1997) developed a survey method for white-tailed deer which utilizes the unique features of branch-antlered males (antler configuration and mass, pelage, and body characteristics) to identify individual males, thereby eliminating the need to commit financial and time resources to capture and mark animals. Population estimates and demographic parameters are derived by this method using the number of individual branch-antlered males and ratios of the number of images of branch-antlered males to the number of images of spikes, females, and fawns. ... ... This method heavily relies on an assumption of equal detection between all age classes and sexes in order to produce reliable population estimates; however, these assumptions may be violated in practice, resulting in biased estimates (Koerth and Kroll 2000;McCoy et al. 2011;Weckel et al. 2011). Various methods, including Weckel et al. (2011), have attempted to correct the Jacobson et al. (1997) method to account for differences in detection between branch-antlered males, spikes, females, and fawns and bias resulting from baited camera sites and different visitation and feeding patterns of males, females, and fawns (Koerth and Kroll 2000;McCoy et al. 2011). However, the amendment proposed by Weckel et al. (2011) does not address variation in detection that exists due to environmental factors or temporal variation in visitation rates. ... Article Full-text available Automated cameras have become increasingly common for monitoring wildlife populations and estimating abundance. Most analytical methods, however, fail to account for incomplete and variable detection probabilities, which biases abundance estimates. Methods which do account for detection have not been thoroughly tested, and those that have been tested were compared to other methods of abundance estimation. The goal of this study was to evaluate the accuracy and effectiveness of the N-mixture method, which explicitly incorporates detection probability, to monitor white-tailed deer (Odocoileus virginianus) by using camera surveys and a known, marked population to collect data and estimate abundance. Motion-triggered camera surveys were conducted at Auburn University’s deer research facility in 2010. Abundance estimates were generated using N-mixture models and compared to the known number of marked deer in the population. We compared abundance estimates generated from a decreasing number of survey days used in analysis and by time periods (DAY, NIGHT, SUNRISE, SUNSET, CREPUSCULAR, ALL TIMES). Accurate abundance estimates were generated using 24 h of data and nighttime only data. Accuracy of abundance estimates increased with increasing number of survey days until day 5, and there was no improvement with additional data. This suggests that, for our system, 5-day camera surveys conducted at night were adequate for abundance estimation and population monitoring. Further, our study demonstrates that camera surveys and N-mixture models may be a highly effective method for estimation and monitoring of ungulate populations. ... Finally, in more vocal species such as red deer Cervus elaphus, roaring counts do not appear to be reliable indicators of abundance (Douhard et al. 2013). Jacobson et al. (1997) established a camera survey methodology for surveying white-tailed deer that has been used widely by managers and researchers. Though it is not a panacea, it provides reasonable demographic information in forested areas (DeYoung 2011). ... ... Our objective was to determine if recruitment calculated from camera surveys was consistent with radiotag-based fawn survival estimates collected concurrently at the same site. The Jacobson et al. (1997) survey method is widely advocated and used by managers and hunters in the United States (e.g. see Thomas, Jr. 2010, a book devoted to the use of cameras by managers and hunters and published by the Quality Deer Management Association), so our objective was not to control for the many intricacies related to camera densities, deer densities, or detection probabilities. ... ... from the same site. The survival estimates and 95% confidence intervals (2007-2012, in We estimated recruitment using camera survey data across the same six years, generally following the procedures of Jacobson et al. (1997). We deployed 20 cameras in 2007 (1 per  1000 ha), 36 in 2008 (1 per 40.5 ha), and 45 in 2009-2012 (1 per 215 ha). ... Article Full-text available Camera surveys commonly are used by managers and hunters to estimate white-tailed deer Odocoileus virginianus density and demographic rates. Though studies have documented biases and inaccuracies in the camera survey methodology, camera traps remain popular due to ease of use, cost-effectiveness, and ability to survey large areas. Because recruitment is a key parameter in ungulate population dynamics, there is a growing need to test the effectiveness of camera surveys for assessing fawn recruitment. At Savannah River Site, South Carolina, we used six years of camera-based recruitment estimates (i.e. fawn:doe ratio) to predict concurrently collected annual radiotag-based survival estimates. The coefficient of determination (R2) was 0.445, indicating some support for the viability of cameras to reflect recruitment. We added two years of data from Fort Bragg Military Installation, North Carolina, which improved R2 to 0.621 without accounting for site-specific variability. Also, we evaluated the correlation between year-to-year changes in recruitment and survival using the Savannah River Site data; R2 was 0.758, suggesting that camera-based recruitment could be useful as an indicator of the trend in survival. Because so few researchers concurrently estimate survival and camera-based recruitment, examining this relationship at larger spatial scales while controlling for numerous confounding variables remains difficult. Future research should test the validity of our results from other areas with varying deer and camera densities, as site (e.g. presence of feral pigs Sus scrofa) and demographic (e.g. fawn age at time of camera survey) parameters may have a large influence on detectability. Until such biases are fully quantified, we urge researchers and managers to use caution when advocating the use of camera-based recruitment estimates. ... Application to white-tailed deer study White-tailed deer play important cultural, economic, and ecological roles throughout their range, and reliable techniques are needed to monitor deer population dynamics and to guide management decisions. Remote cameras have become increasingly popular monitoring methods for white-tailed deer due to their low-cost and noninvasive nature (Chitwood et al., 2017;Curtis et al., 2009;Jacobson et al., 1997;Johnson et al., 2021;Keever et al., 2017;Roberts et al., 2006). ... ... Additionally, the REST model still relies upon independent estimation of the camera detection zone. Traditional protocols for estimating population size of white-tailed deer from camera surveys are based on individual recognition of adult males within a sampled area based on antler characteristics (Jacobson et al., 1997;Weckel et al., 2011). These estimates are derived from ratios of photographic occurrences of branch-antlered bucks, spike bucks, does, and fawns at baited locations (Jacobson et al., 1997). ... ... Traditional protocols for estimating population size of white-tailed deer from camera surveys are based on individual recognition of adult males within a sampled area based on antler characteristics (Jacobson et al., 1997;Weckel et al., 2011). These estimates are derived from ratios of photographic occurrences of branch-antlered bucks, spike bucks, does, and fawns at baited locations (Jacobson et al., 1997). A major limitation to this technique is that it does not provide measures of uncertainty surrounding the parameter estimates. ... Article Long‐term monitoring is an important component of effective wildlife conservation. However, many methods for estimating density are too costly or difficult to implement over large spatial and temporal extents. Recently developed spatial mark‐resight (SMR) models are increasingly being applied as a cost‐effective method to estimate density when data include detections of both marked and unmarked individuals. We developed a generalized SMR model that can accommodate long‐term camera data and auxiliary telemetry data for improved spatio‐temporal inference in monitoring efforts. The model can be applied in two‐stages, with detection parameters estimated in the first stage using telemetry data and camera detections of instrumented individuals. Density is estimated in the second stage using camera data, with all individuals treated as unmarked. Serial correlation in detection and density parameters is accounted for using time‐series models. The two‐stage approach reduces computational demands and facilitates the application to large datasets from long‐term monitoring initiatives. We applied the model to three years (2015‐2017) of white‐tailed deer (Odocoileus virginianus) data collected in three study areas of the Big Cypress Basin, Florida, USA. Fifty‐nine females marked with ear‐tags and fitted with GPS‐telemetry collars were detected along with unmarked females on 180 remote cameras. Most of the temporal variation in density was driven by seasonal fluctuations, but one study area exhibited a slight population decline during the monitoring period. Modern technologies such as camera traps provide novel possibilities for long‐term monitoring, but the resulting massive datasets, which are subject to unique sources of observation error, have posed analytical challenges. The two‐stage spatial mark‐resight framework provides a solution with lower computational demands than joint SMR models, allowing for easier implementation in practice. In addition, after detection parameters have been estimated, the model may be used to estimate density even if no synchronous auxiliary information on marked individuals is available, which is often the case in long‐term monitoring. ... While classification accuracy is subject to variability from aspects such as image-based constraints (Stevick et al. 2001, Meek et al. 2015 and vegetation conditions ( a sightability (photos/deer) ratio (Jacobson et al. 1997). This ratio is then applied to the numbers of doe and fawn images captured with the same camera traps to generate estimates for these sexage classes. ... ... This ratio is then applied to the numbers of doe and fawn images captured with the same camera traps to generate estimates for these sexage classes. Of course, this method primarily relies on an observer's ability to identify individual bucks based on unique antler characteristics (Jacobson et al. 1997, Koerth 1997; however, resulting estimates also are heavily influenced by correct classification at the sex-age level. Newbolt and Ditchkoff (2019) found that the sex-age category of a white-tailed deer was the most important predictor of classification accuracy with branch-antlered bucks classified most accurately, followed by does and fawns, respectively. ... ... It is generally recognized that species with high visual variation between conspecifics, such as unique natural markings (e.g., spots of a cheetah [Acinonyx jubatus]) or secondary sexual traits (e.g., antlers of a white-tailed deer [Odocoileus virginianus]), may lead to more reliable classification at the individual, sex, or age-class category(Johansson et al. 2020). Conversely, accurately classifying species where individuals may appear visually similar to each other (cougars, Puma concolor), may provide additional challenges for observers(Kelly et al. 2008, Oliveira-Santos et al. 2010).Since a novel approach was developed byJacobson et al. (1997), commonly referred to as the Individual Branched Antlered Method (IBAM), camera surveys have become a widespread method of estimating parameters of white-tailed deer populations. The IBAM method relies on identifying individual bucks based on unique antler characteristics and creating ... Thesis Full-text available Thousands of captive white-tailed deer (Odocoileus virginianus) facilities exist across North America for the purpose of producing trophy-quality deer (i.e., exceptionally large-antlered). Many of these deer get marketed to private landowners with the expectation that introduced deer will enhance genetics in the population, resulting in larger-antlered male deer. Previous research suggests that white-tailed deer experience highly variable survival and reproductive success post-translocation, however, little is known about the fate of translocated white-tailed deer sourced from captive-breeding operations. We translocated 24 adult female deer over a 3-year period into a private, 300-ha high-fence enclosure in east-central Alabama. We monitored survival, reproductive success, and fawn recruitment of the translocated deer using VHF radio collars and vaginal implant transmitters (VITs). We found that survival rates were greater than studies where deer were translocated from the wild, but fawn survival and recruitment was poor. We believe our findings provide a baseline of expectations for captive deer translocations. Our following research objectives focus on improving camera survey output for white-tailed deer by reducing sex-age misclassifications. Previous research suggests that misclassifications may be an important source of error in wildlife camera surveys. We developed and tested the effects of species-specific training material designed to reduce sex-age misclassification associated with white-tailed deer images. We found exposure to training material produced the greatest significant improvement on classification accuracy of deer images compared to any other respondent-based factors we investigated. We also found that other experiential factors were positively associated with classification accuracy of deer images. Our findings suggest that use of species-specific training material can reduce misclassifications, leading to more reliable data. ... Therefore, numerous indexes have been developed which use marked and/or unmarked individuals to estimate population growth and provide correction factors for behavioral (e.g., imperfect detection) or survey (e.g., number of sampling units) limitations, allowing estimates to be converted to absolute population numbers. For example, indexes including genetic mark-recapture (Ebert et al. 2012), distance sampling (Anderson et al. 2013), aerial infrared camera surveys (Naugle et al. 1996;White et al. 2001;Haroldson et al. 2003;DeCesare et al. 2012), and remote camera surveys (Jacobson et al. 1997;Koerth and Kroll 2000;Roberts et al. 2006;Watts et al. 2008; Dougherty and Bowman 2012) have provided advancements in estimating ungulate population dynamics. However, these indexes often have assumptions that are commonly difficult to meet (e.g., perfect detection; Weckel et al. 2011), are expensive (e.g., aerial counts; Storm et al. 2011), are difficult to apply over extensive areas (e.g., animal movements; Rowcliffe et al. 2009), or do not provide independent estimates of vital rates (e.g., camera surveys; Jacobson et al. 1997). ... ... For example, indexes including genetic mark-recapture (Ebert et al. 2012), distance sampling (Anderson et al. 2013), aerial infrared camera surveys (Naugle et al. 1996;White et al. 2001;Haroldson et al. 2003;DeCesare et al. 2012), and remote camera surveys (Jacobson et al. 1997;Koerth and Kroll 2000;Roberts et al. 2006;Watts et al. 2008; Dougherty and Bowman 2012) have provided advancements in estimating ungulate population dynamics. However, these indexes often have assumptions that are commonly difficult to meet (e.g., perfect detection; Weckel et al. 2011), are expensive (e.g., aerial counts; Storm et al. 2011), are difficult to apply over extensive areas (e.g., animal movements; Rowcliffe et al. 2009), or do not provide independent estimates of vital rates (e.g., camera surveys; Jacobson et al. 1997). For these reasons, radiotelemetry studies of marked animals have commonly been used to estimate population growth from key vital rates (e.g., DeCesare et al. 2012). ... ... Third, radiotelemetry is often labor intensive and expensive due to capture and marking of animals , which can limit these studies to small geographic areas (Tempel and Gutiérrez 2013). In contrast, occupancy studies allow geographically extensive areas to be surveyed because only detection/nondetection or count data of unmarked individuals is needed and can be collected with less overall labor (i.e., marking), compared to other remote camera-based estimators (e.g., Jacobson et al. 1997) that require identifying individuals. Remote cameras are particularly useful for simultaneously collecting ungulate abundance (Watts et al. 2008; Dougherty and Bowman 2012) and age ratios (Ikeda et al. 2013), which can provide information on maximum sustainable mortality for adult females (Bender 2006 can be useful to estimate detection rates (Fuller 1990), but locating these animals may be tedious and require marked animals to have working transmitters and remain in the study area. ... ... Cameras are effective at detecting a wide range of larger mammal species, including carnivores and herbivores, depending on the setup and bait used. Motion-triggered cameras are being used more often to inventory and monitor ungulates and lagomorphs (Cutler and Swann 1999, Jacobson et al. 1997, Jennelle et al. 2002, Main and Richardson 2002, McCullough et al. 2000, Sweitzer et al. 2000. Cameras have increased in use, in part, because of the high probability of detecting a variety of species, including many species that are otherwise difficult to detect (Foresman and Pearson 1998). ... ... Cameras have increased in use, in part, because of the high probability of detecting a variety of species, including many species that are otherwise difficult to detect (Foresman and Pearson 1998). The reliability of the method is greatest when cameras are placed at sites where target species are lured in with food or water (Cutler and Swann 1999, Jacobson et al. 1997, Koerth and Kroll 2000, Sweitzer et al. 2000. Thus, the survey method described here is a combination array of trackplates and cameras designed to detect as broad an array of medium-and largebodied mammals as possible. ... Book Full-text available McKenzie, M.M.; Weller, T.J.; Weckerly, F.W.; Vojta, C. 2006. Multiple species inventory and monitoring technical guide. Gen. Tech. Rep. WO-73. Washington, DC: U.S. Department of Agriculture, Forest Service, Washington Office. 204 p. Disclaimer The U.S. Department of Agriculture (USDA) prohibits discrimination in all its programs and activities on the basis of race, color, national origin, age, disability, and where applicable, sex, marital status, familial status, parental status, religion, sexual orientation, genetic information, political beliefs, reprisal, or because all or part of an individual's income is derived from any public assistance program. (Not all prohibited bases apply to all programs.) Persons with disabilities who require alternative means for communication of program information (Braille, large print, audiotape, etc.) should contact USDA's TARGET Center at (202) 720-2600 (voice and TDD). To file a complaint of discrimination, write USDA, Director, Office ... A few methods have been developed that use the branching patterns of the antlers of mature male deer (bucks) as individually distinctive markings. Jacobson et al. (1997) used camera traps to survey deer and used these branching antler patterns as recorded in the photographs to count bucks. The ratio of individual bucks to the total number of buck observations was used to extrapolate the abundances of the non-identifiable demographic groupsadult females (does), fawns of both sexes, and immature males (spikes) -from the respective total observations of each. ... ... However, a few areas of improvement remained. Both Jacobson (1997) and Weckel et al. (2011a) used the raw count of bucks from the photographs in their protocols, rather than incorporating some correction for imperfect capture rate, e.g., via a mark-recapture analysis. Also, the Jacobson and Weckel et al. estimators both calculate a final herd abundance which then needs to be converted to a density via an ad hoc judgement of the study area. ... Article Overbrowsing by highly abundant white-tailed deer (Odocoileus virginianus) negatively impacts the regeneration of the forest understory throughout the eastern United States. Deer management programs are often used by land managers to reduce deer densities and promote forest regeneration. This study examines the impact of a 15-year-long archery-based deer management program on the understory of a nature preserve in southern NY consisting of an old-growth hemlock and second-growth mixed hardwood forest. Vegetation plots were sampled every 3–5 years between 2004 and 2019, while deer density was estimated using camera trap survey data annually since 2009. Generalized mixed-effects models were used to determine the influence of deer density, forest type, canopy cover, and time on species richness, native stem density and total stem density. The most predictive models showed an increase in richness as time went on. Additionally, stem density had a negative relationship with deer density (i.e., stem density and species richness increased as deer density declined over time). For both native and total stem density, the highest-ranked model included only deer density as a predictor. Generally, woody species richness and stem density increased in the seedling (<0.3 m tall) and sapling (0.3–0.9 m tall) size classes but remained relatively constant for the transgressive (>0.9 m) size class over time and as deer density decreased. Many native species exhibited density increases in the smallest size classes, but black birch (Betula lenta), American beech (Fagus grandifolia), and mapleleaf viburnum (Viburnum acerifolium) were the only native species to increase in the transgressive (>0.9 m tall) class. Several non-native species, however, did increase in the transgressive size class since 2004. These results indicate that the forest has improved as a result of the DMP, but long-term recruitment of native species is still uncertain. The DMP has shown the potential to help restore woody regeneration but monitoring should continue to ultimately determine whether deer management can allow for true recruitment of native seedlings into the forest understory and canopy. ... Additionally, these species are economically important in many countries where there is regulated harvest and their presence leads to conservation gains in the environment [3,4]. Given these important roles and regulations, many government institutions and researchers have implemented long-term monitoring programs to inform management of ungulate populations [5,6]. ... ... They are particularly useful to obtain data to estimate population sizes of species that are uniquely identifiable [15]. While adult male white-tailed deer are uniquely identifiable for a portion of the year based on antler characteristics [5,16]; adult females are less reliably identifiable. However, fawns are born with spot patterns that can be used to uniquely identify individuals with camera traps [17]. ... Article Full-text available Many ungulates are spotted as neonates. This trait is unique to individuals, making their identification feasible from remote cameras. Key deer (Odocoileus virginianus clavium) are an endangered subspecies of white-tailed deer endemic to the lower Florida Keys, U.S.A. Habitat loss and hunting were historical drivers of population decline but recent studies report positive associations of key deer with urbanization. Using opposing camera traps at 56 sites throughout the National Key Deer Refuge on Big Pine Key, we used spot patterns to uniquely identify and estimate fawn abundance with N-mixture models. We further compared those inferences to models informed by adult doe counts to see how well tracking adult females alone corresponded with fawn habitat associations. Our results indicated that fawn abundance was negatively associated with increasing elevation and human trails, contrary to models based on adult female observations alone. The lowest elevations where fawns were most abundant were associated with dense wetland plant communities, which were likely selected for thermal cover and warrant further investigation given that those areas are most vulnerable to sea-level rise. Our methods showcase the utility of identifying neonates from camera trap photos and draw attention to possible misaligned inferences when tracking adult females in isolation. ... Motion activated trail cameras (M-880 (Gen 2), Moultrie, Birmingham, AL, USA) were placed over each 4-poster device from 10 July -17 August 2018 in an attempt to quantify the number of deer that utilized both the property and 4-poster devices. We used a modified version of the Jacobson et al. (1997) method for censusing white-tailed deer using trail cameras. Jacobson et al. (1997) called for using antler configuration to identify individual males in order to establish a population cohort of known abundance with which to compare frequency of photographs with the doe and fawn cohorts. ... ... We used a modified version of the Jacobson et al. (1997) method for censusing white-tailed deer using trail cameras. Jacobson et al. (1997) called for using antler configuration to identify individual males in order to establish a population cohort of known abundance with which to compare frequency of photographs with the doe and fawn cohorts. The paucity of branch-antlered bucks on Manresa Island prevented us from using this technique, but we had a cohort of easily identifiable uniquely ear-tagged does. ... Article The lone star tick, Amblyomma americanum, is a common human-biting species whose range has been largely restricted to the southeastern United States, until recent detections of established populations on Long Island, New York and throughout coastal southern New England. We evaluated the effectiveness of topical treatment of 10% permethrin delivered via 4-poster devices to white-tailed deer, Odocoileus virginianus, in the management of a newly discovered A. americanum population in Norwalk, Connecticut. Using a high-density deployment of one 4-poster device/12.7 ha, we were successful in significantly reducing densities of host-seeking adults (93% reduction), nymphs (92%), and larvae (96%) from 2018 to 2020. We also documented a significant reduction (87%) in parasitizing adults and nymphs on white-tailed deer from 2018 to 2019. The prevalence of Ehrlichia chaffeensis and Ehrlichia ewingii combined in host-seeking adults declined significantly from 47% at the time the A. americanum population was discovered in 2017 to 7% in 2020. However, the prevalence in nymphs remained static (∼9%) throughout the study period. These data demonstrate that, when properly deployed in a density-dependent manner in terms of deer abundance, 4-poster devices can effectively manage parasitizing and host-seeking A. americanum populations and reduce the prevalence of two ehrlichial species of public health importance. ... Following other studies that used remote game cameras to census wildlife based on identifiable subjects (e.g., white-tailed deer) [40,41], we developed a method for estimating the identifiable segment of wild pig populations to test trap effectiveness. Effectiveness refers to the proportion of the population removed based on population size as estimated by the Lincoln-Petersen method. ... ... To estimate effectiveness (i.e., the proportion of the population removed based on population size), we had to estimate population size. Previous studies have used remotely triggered cameras to uniquely identify ("mark") individual subjects from antlers, stripes, coat patterns and more [40,41,[45][46][47][48]. Wild pigs vary considerably in their coat patterns and color [10], so we "marked" individually identifiable pigs during camera surveys based on coat patterns and colors, and other physically unique traits (e.g., scars, cuts, malformations). ... Article Full-text available Strategic control and eradication programs for wild pigs (Sus scrofa) are being developed to help curtail the expanding populations of this invasive, alien species. Drop nets and corral traps have a long history of capturing a multitude of wildlife species, so we evaluated the effectiveness and efficiency of these traps for controlling wild pigs in southern Oklahoma. We also developed and evaluated a suspended metal trap that provided real-time monitoring and deployment to capture animals. Effectiveness of each trap type was estimated as the proportion of pigs removed from the total population, whereas efficiency was calculated based on catch per unit effort (CPUE) (i.e., the number of person hours per pig removal). During 3 years of study (2010–2012), we removed 601 pigs, 296 using drop nets, 60 using corral traps, and 245 using suspended traps. Suspended traps removed 88.1% of the estimated population, whereas drop nets removed 85.7% and corral traps removed 48.5%. CPUE was 0.64 person hours/pig using suspended traps followed by 1.9 person hours/pig for drop nets and 2.3 person hours/pig for corral traps. Drop nets and suspended traps were more effective at removing a large proportion of the population (>85%), mainly through whole sounder removal, but the suspended trap with real-time notifications was the most efficient trap type, requiring fewer person hours to operate. ... At AA, CLIF and FC, we conducted baited camera surveys using tagged antlerless deer (adult females of which 90% were tagged, female fawns, and incidental male fawns) to estimate abundance (Jacobson et al. 1997, Curtis et al. 2009). We used game cameras (D-80 White Flash Trail Cameras, Moultrie, Alabaster, AL, USA) set on motion activated single shot with a 5-minute delay to optimize capture rates relative to photo storage. ... ... Our study areas did not have fully closed populations, but there was likely minimal outside exchange given deer philopatry, relatively small suburban home ranges, and the camera surveys' short duration. Because the resulting population estimate and confidence intervals for our method were for antlerless deer only, we used the buck:doe ratio (BDR) method to estimate the number of individual antlered males (Jacobson et al. 1997). We then added the number of individual antlered males identified using the BDR method to the antlerless estimates from Program NOREMARK to obtain an overall population estimate. ... Article Overabundant suburban deer (Odocoileus spp.) are a source of human‐wildlife conflict in many communities throughout the United States. Deer‐vehicle collisions, impacts to local vegetation, tick‐borne pathogens, and other negative interactions are typical reasons cited for initiating deer management programs. Social attitudes, legal constraints, and perceived safety concerns lead many communities to examine nonlethal management options. Surgical sterilization is currently the only nonlethal method available to permanently sterilize females with a single treatment. However, there are limited data demonstrating methods and outcomes in management programs that sterilize a high percentage (>90%) of local populations of females, particularly regarding the impact of immigration on non‐isolated populations. We present data from 6 surgical sterilization sites with geographically open populations in California, Maryland, Michigan, New York, Ohio, and Virginia, USA. From 2012 to 2020 we sterilized 493 deer, primarily via ovariectomy, and conducted annual or periodic population estimates using camera surveys, road‐based distance sampling, and intensive field observations to assess population trends. Study sites ranged from 1.2 km2 to 16.5 km2 with ~47–169 individuals, resulting in approximate densities of 6–63 deer/km2. For all sites we noted an average reduction of ~26% (17%–36%) from Year 1 to Year 2. Four years after initial treatment, we documented an average population reduction of ~45% (29%–56%). During the first year, the average cost per deer sterilized at locations where bait was used was US1,185 ($927–$1,572). Surgical sterilization projects demonstrate that significant reductions in local deer densities using high‐percentage, surgical sterilization programs can be achieved in non‐insular locations, where baited deer are approachable by vehicle for darting. Sustained sterilization efforts may be necessary, as is the case with all deer management programs, in areas where immigration is possible, and all the animals are not sterilized.
... We used methods described by Sanderson and Harris (2013) to calculate total effort per camera, species activity patterns, and density uncorrected for imperfect detection. We created encounter histories for every identifiable deer in each overwash fan from August 1 to November 24 of each year and calculated an estimate of local abundance (Jacobson, Kroll, Browning, Koerth, & Conway, 1997). Identifiable deer were differentiated through (a) presence of a uniquely colored radio collar or (b) antler points and conformation for males. ...
... Pop. factor = Population factor fromJacobson et al. (1997). Number of deer using OW = Population factor × Total number of deer observed. ...
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Abstract Coastal resilience is threatened as storm‐induced disturbances become more frequent and intense with anticipated changes in regional climate. After severe storms, rapid recovery of vegetation, especially that of dune‐stabilizing plants, is a fundamental property of coastal resilience. Herbivores may affect resilience by foraging and trampling in disturbed areas. Consequently, assessing the impacts of herbivores on recovering vegetation is important for coastal land management. We combined imagery classification, wildlife monitoring, and trend analysis to investigate effects of white‐tailed deer on recovery rates of vegetation four years poststorm in nine overwashed areas. We estimated local deer density with trail cameras, how it relates to an index of primary productivity, and assessed the relationship between deer density and rates of vegetation recovery in overwash fans. Prestorm vegetation cover consisted of shrubs and sporadic patches of beach grass. Poststorm cover was dominated by beach grass. At current rates, vegetation coverage will return to prestorm conditions within the decade, though community transition from grasses to shrubs will take much longer and will vary by site with dune formation. The effect of deer on rates of vegetation recovery was negative, but not statistically significant nor biologically compelling. Although effects of deer trampling on beach grass are evident in classified imagery, deer foraging on beach grass had little effect on its rate of spread throughout overwash fans. While the rate of spread of the primary dune‐building grass was not deleteriously affected by deer, locally high deer densities will likely affect the future establishment and development of herbs and shrubs, which are generally more palatable to deer than beach grass.
... Camera traps have been useful in identifying white-tailed deer population characteristics (e.g., McKinley et al. 2006;McCoy et al. 2011) and have allowed for the identification of some temporal developmental phases such as the presence of offspring, pregnant females, and the moment in which the hard antlers of the males become apparent (e.g., McKinley et al. 2006;Soria-Días and Monroy-Vilchis 2015). Some studies have even made possible the identification of individual males based on antler configurations (Jacobson et al. 1997). ...
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Hunting activity in Mexico is regulated by the Secretaria de Medio Ambiente y Recursos Naturales (SEMARNAT), a Federal agency which also approves management plans and annual harvest rates. The official calendar for white-tailed deer hunting season in Mexico comprises a single season that runs from November to March. To determine the congruence of the current hunting calendar with the seasonal timing of hard antlers of white-tailed deer in the wetlands of Campeche in southeastern Mexico, we used data obtained from 10 camera trap surveys performed from 2010 to 2017. In the pictures of white-tailed deer, we identified the timing of the presence of different antler developmental stages (velvet, hard antlers, and no antlers) as well as the occurrence of fawns. We obtained 1071 pictures of deer with antlers in velvet stage, 128 with hard antlers, 16 with no antlers, and 414 pictures of fawns. We observed that pictures of deer with antlers in velvet stage occurred from February to July, hard antlers from May to October, and no antlers from the second part of November to January. We also observed that the fawning season ran from February to June. Our results indicate that the reproductive season in Campeche wetlands is different from what occurs in the northern latitudes of Mexico and southern USA. Because the timing of the white-tailed deer antler development in our study area does not coincide with the official hunting season established in Mexico, we believe it is necessary to modify the official hunting season for the Campeche wetland area. Sport hunting should be permitted from August to October, based on the timing of deer with hard antlers.
... Sequential frames of the same species were counted as one photographic event, and unless individual identification was possible, any subsequent photograph of the same species taken within 1 h was not considered a new photographic event. Individual identification possibly relied on permanent scars (Jacobson et al., 1997), neck thickness in proportion to body (Gonz alez-Marίn et al., 2008), the presence and form of antlers or the presence of fawn in the case of females. The location of each photograph was recorded by latitude and longitude and converted into digital data in GIS using ArcMap program. ...
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There is an urgent recognized need for conservation of tropical forest deer. In order to identify some environmental factors affecting conservation, we analyzed the seasonal habitat use of two Indonesian deer species, Axis kuhlii in Bawean Island and Muntiacus muntjak in south-western Java Island, in response to several physical, climatic, biological, and anthropogenic variables. Camera trapping was performed in different habitat types during both wet and dry season to record these elusive species. The highest number of photographs was recorded in secondary forest and during the dry season for both Bawean deer and red muntjac. In models, anthropogenic and climatic variables were the main predictors of habitat use. Distances to cultivated area and to settlement were the most important for A. kuhlii in the dry season. Distances to cultivated area and annual rainfall were significant for M. muntjak in both seasons. Then we modelled their predictive range using Maximum entropy modelling (Maxent). We concluded that forest landscape is the fundamental scale for deer management, and that secondary forests are potentially important landscape elements for deer conservation. Important areas for conservation were identified accounting of habitat transformation in both study areas. Download this article in: https://authors.elsevier.com/a/1V9Kc,Q4YJFjEt free access valid for 50 days, until July 23, 2017
... Until recently, few methodologies for assessing deer impact on forest vegetation were linked to deer density. Now, techniques are available to forest landowners for estimating deer density and impact (Jacobson et al. 1997, deCalesta 2013, Pierson and deCalesta 2015. State natural resource agencies generically address forest landowner complaints about high deer density and impact by issuing permits to increase harvest of antlerless deer and reduce deer density and impact, but when such permits are issued at the DMU level, they do not allow individual forest landowners to direct hunters with permits to use them exclusively on their properties. ...
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White-tailed deer (Odocoileus virginianus) are managed at 2 levels: by federal, state, or local resource agencies on large, heterogeneous landscapes usually >200 ha; and by individual property owners on smaller (generallyha) and more discrete forestlands. This dichotomy results in a management disconnect: regulations controlling deer hunting (seasons and bag limits) are developed by agencies for landscapes the size of deer management units (DMU) and often are not sufficiently area-specific to meet management needs of individual forest landowners. Resource agencies manage hunters and regulate deer abundance by controlling harvest within DMUs, and they use license and permit fees paid by hunters to finance the costs of agency deer management, including law enforcement. Some, such as the Pennsylvania Game Commission (PGC), derive income from timber harvest on landscapes they manage (gamelands) as an additional source of revenue and may use it for habitat enhancement that favors deer and other wildlife species. Most deer management occurs on forestlands where habitat (forage, cover, water, plant composition) is manipulated by landowners. Landowners absorb the costs of management that affect deer habitat, abundance, and impact on natural resources. Costs include herbicide application to control unwanted vegetation resulting from overabundant deer; development and maintenance of roads hunters use to gain access to deer hunting; activities associated with managing deer harvest (posting boundaries, repairing road damage); and measures, including fencing, to protect forest resources from damages caused by overabundant deer. Other costs, like thinning or timber harvest, which produce deer forage, are partially or wholly off set by the sale of resulting forest products. Unlike agencies, costs to forest landowners of managing deer and hunting access are rarely subsidized by hunters (a notable exception was the PGC program to provide deer fencing materials to protect tree regeneration on forest landowner properties), but rather are borne by forest landowners—unless landowners lease hunting rights to hunters for a fee. The disconnect and resultant emphasis on deer management at the DMU level by agencies rather than individual forestlands favors the priorities of hunters (bigger and more deer) that conflict with those of landowners whose resources and revenues may be negatively impacted by high deer density. The situation results from the history of deer management, which must be placed in perspective along with the importance and influence of stakeholders, who affect an organization’s objectives (Freeman 1984).
... We then moved these points to the nearest ranch road, utility right-of-way, or sendero. We did not bait stations to prevent heterogeneous capture probability (Jacobson et al. 1997;White and Shenk 2001). We followed camera placement guidelines established by Heilbrun et al. (2003). ...
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Ineffective survey methods of carnivores limit the ability of managers and researchers to make sound research conclusions and management recommendations. Because bobcats (Lynx rufus) are individually identifiable due to their unique coat patterns, it may be possible to obtain density estimates using capture-recapture models. We photo-trapped bobcats on the 3,156-ha Welder Wildlife Foundation Refuge in southern Texas from September 2000 through August 2001 to determine whether automatically triggered cameras could produce reliable estimates of bobcat density. Using the Schumacher-Eschmeyer estimator, we obtained an abundance estimate of 15 individuals (95% C***I = 13.6–16.7) from 56 bobcat photographs. Our estimate was comparable to bobcat densities previously reported on our study area. This technique has the potential to provide wildlife managers and researchers with reliable data on bobcat abundance not previously available without the expense of physical capture and radiotelemetry. Our relatively high photographic success might be attributable to the dense chaparral-type vegetation and the large network of travel pathways available on our study area. These methods may not be as successful in open areas or where bobcat travel is not predictable. We encourage replication of this technique elsewhere in bobcat range where density, vegetation, and travel pathways differ.
... In August of 2011 and 2012, we established 100 standardized forage patches with ~20 kg of corn (Zea mays) and monitored each with a single camera trap (i.e., 50 sites established August 1 and 50 sites established August 8) and cameras were able to detect researchers consistently out to a maximum distance of 21m with the maximum width of 8m (see Lashley et al. 2014 b for study design details). Each forage patch was established for 14 days to allow deer to adopt the new forage patch into their daily foraging activity and then we refreshed the corn and activated cameras to take pictures for 14 days and as ourfrequently as every 3 minutes (Jacobson et al. 1997). After the 14 days of camera trapping, we collected all pictures and tallied the group size, sex, age of the oldest male, group type (mixed-or single-sex), group feeding rate by sex, time and date of the picture, and distance of the forage patch to escape cover. ...
Article
Nearly all species of sexually dimorphic ungulates sexually segregate. Several hypotheses have been proposed to explain this phenomenon, including the social-factors hypothesis (SFH) and the predation hypothesis (PH). Interestingly, previous studies have accepted and rejected each hypothesis within and across species but few studies have simultaneously tested both hypotheses in the same population. In August 2011 and 2012 using 7,680 photographs taken with camera traps in standardized forage patches, we tested two predictions of the SFH: 1) foraging efficiency of both sexes would decrease when foraging rate in mixed-sex groups relative to single-sex groups, and 2) activity patterns (i.e., the pattern of temporal use of forage patches on a diel scale) of the sexes would decrease in temporal overlap at the forage patch level (i.e., social segregation) compared to the overall temporal overlap of activity patterns of the population. Also, we tested two predictions of the PH: 1) the relationship between feeding rates of each sex, and 2) temporal activity overlap would change with changing risk level of forage patches as a result of differing risk perception between sexes. In support of the SFH for temporal segregation, when in mixed-sex groups, mature males and all females decreased feeding rate 30% and 10%, respectively; further, the sexes had similar activity patterns overall (94-95% overlap), though temporal overlap was lower in individual forage patches (68-74% overlap). In multi-male mixed sex groups, at least one male exhibited aggressive posture toward females during all foraging bouts suggesting intersex aggression was the cause of the observed decrease in foraging rates. In support of the PH, the sexes adjusted feeding rate differently in response to changing risk level of a forage patch, encouraging spatial segregation; however, the PH was not supported for temporal segregation because temporal activity pattern overlap did not vary as a function of predation risk. Coupling our results with previous reports indicates that the SFH is supported for only temporal segregation of forage patch use, and the PH may only be supported for spatial segregation in forage patch use. Thus, both social factors and predation risk may interact to encourage sexual segregation.
... Such "marked" approaches are difficult to apply on "unmarked" species such as white-tailed deer, for which reliable identification of individuals from photographs is difficult. Jacobson et al. (1997) proposed a population estimator for whitetailed deer using data from camera surveys in which individual males were identified using antler variation (see also Watts et al. 2008). Such an approach has potential, but Moore et al. (2013) showed the method underestimated known deer populations by 32% on average. ...
... More available and widespread devices are triggered trail cameras that are used for moose and other wildlife research to study their activity and behaviour (Foster andHumphrey 1995, Main andRichardson 2002) or to estimate population size (Jacobson et al. 1997, Sweitzer et al. 2000, Roberts et al. 2006) and for other wildlife studies. It is an advantage of camera traps to work independently of observers and storage data within battery lifespan. ...
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The moose (id. European Elk) (Alces alces Linnaeus, 1758) is an inherent component of the forest ecosystem in Lithuania. It is an important game species harvested within its range. Without human intervention, wildlife including moose can increase in numbers up to marked overpopulation followed by disease, starvation and damage caused to forestry. Although nature has its own ways of controlling wildlife populations, these ways could be much less humane that modern hunting. Population management decisions include appropriate harvest levels, timing of hunting seasons, habitat carrying capacity and habitat management practices. We have queried publications and internet-based resources to determine the moose population dynamics and changes predicted for different habitats and conditions. The existing population management models and methodology were analysed.
... Annual necropsies (autopsies) conducted by biologists, with the public participating and observing, provide significant data related to herd health, especially if herd health metrics have been developed through geographically relevant research. Infrared-triggered trail cameras also can provide excellent information on a host of herd health metrics (Jacobson, et al. 1997, Koerth, et al. 1997, Koerth and Kroll 2000, including fawn crop and true recruitment (viz., percentage of fawns that reach one year of age). ...
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Indigenous peoples manage forestlands and wildlife differently than public and private forestland managers. To evaluate ecological outcomes from these differences, we compared the structure, composition, and diversity of Ojibwe and Menominee tribal forests to nearby nontribal forestlands in northern Wisconsin. These indigenous peoples seek to manage forests for mature conditions, accommodate wolves and other predators, and hunt deer to sustain traditional livelihood values. Their forests are often more mature with higher tree volume, higher rates of tree regeneration, more plant diversity, and fewer invasive species than nearby nontribal forestlands. In contrast, nontribal forestlands lost appreciable plant diversity in the 20th century and have failed to regenerate tree species sensitive to deer herbivory. Ensuing shifts in forest composition and wildlife populations have jeopardized the ability of managers to sustain wildlife and meet certification standards on nontribal forestlands. Lessons from tribal forestlands could help improve the sustainable management of nontribal public forestlands.
... We excluded 210 counts during May in each year due to the difficulty of distinguishing between calves and adult 211 cows. During analysis, we excluded photos if one or more of the individuals in the photo could 212 not be confidently identified to age or sex (Jacobson et al. 1997, McCoy et al. 2011). Using 213 photos from camera traps to estimate age-and sex-ratios assumes equal detection among the age-214 and sex-classes. ...
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Crop depredation by wildlife is a frequent concern for natural resource managers and mitigation of this issue is often an important task for wildlife agencies. Elk Cervus elaphus and other ungulate species have depredated corn Zea mays at Bosque del Apache National Wildlife Refuge, New Mexico, USA, interfering with the ability of the Refuge to provide sufficient supplemental nutrition to overwintering sandhill cranes Antigone canadensis and geese (Anatidae). We estimated annual adult survival and calf recruitment rates of elk from 2011 to 2013 at Bosque del Apache National Wildlife Refuge. Natural adult survival (excludes human-related mortalities) was high (mean ¼ 98.3%; 95% CI ¼ 95.0–100.0%). Calf recruitment was lower than in some populations, and ranged from 13.0 to 36.7 calves: 100 cows at time of recruitment (March and April) with a mean of 21.9 (SD ¼12.9). Using this information, we constructed a harvest management model to determine annual harvest quotas required to stabilize the growth of the elk herd on the Refuge. The female segment of the herd is growing at an annual rate of 9.0% (95% CI ¼ 1.1–24.1%). To stabilize the growth rate of the female elk population, 8.0% (95% CI ¼ 1.1–19.4%) of the cows would need to be harvested annually. We estimated an adult elk abundance of 40.0 (SE ¼ 4.57; 95% CI ¼ 33.8–52.6) in 2012 and 61.1 (SE ¼ 7.21; 95% CI ¼ 49.9–78.8) in 2013. Our harvest management model provides Refuge staff, who ultimately intend to improve corn yield, with valuable information needed to stabilize the elk herd. Further, our approach outlines a simple, easily implemented modeling technique that can be used for the management of other ungulate herds.
... Extremely selective harvest, low hunting pressure limited to archery, and ample nutritious food sources facilitated a high population density within the enclosure. A mark-recapture camera survey (Jacobson et al. 1997) in 2007 estimated a density of at least one deer per 4.2 ac (1.7 ha), three times that normally found in the region, and a sex ratio (M:F) of 2.64:1 (McCoy et al. 2011). ...
Article
Prescribed fire is a cost-effective habitat management tool in pine stands to enhance the quantity and quality of forage available for white-tailed deer (Odocoileus virginianus). Management recommendations typically suggest a 3- to 5-year burn rotation in mixed pine–hardwood stands to increase quality forage production, but as fire frequency increases, forb and legume biomass increases, and woody browse decreases. A more frequent burn rotation may be a viable management option for deer managers, but there is still a lack of information regarding preferred forage and nutritional carrying capacity response to prescribed fire at these intervals. We measured the production and nutritional quality of forage within mature pine–hardwood stands after a 1- or 2-year fire-return interval during three nutritionally stressful periods for deer on a 640-acre (259-hectare) enclosure located in east-central Alabama during 2014 and 2015. These stands had previously been burned annually for over 15 years, resulting in an abundance of herbaceous vegetation. We then compared forage class biomass, nutritional carrying capacity estimates, and digestible protein between burn treatments. A 1-year fire return interval improved habitat quality to a greater degree than a 2-year fire return interval by increasing the production of forage able to support greater nutritional planes. An annual burn rotation is an effective option for managers to increase protein availability in pine–hardwood stands, but other factors such as decreased cover availability and soft mast production should also be considered.
... Using GPS units attached to each helicopter we were able to upload the helicopter flight tracks used during capture to ArcMap 10.3 (ESRI, Redlands, CA, USA) allowing us to add a 200 m buffer (100 m on each side) to the flight tracks, which is the approximate distance from the helicopter an observer can cover when searching for deer ( Figure 2). Drop net coverage was calculated using a 60.7 ha buffer around each drop-net location because a baited camera site has been shown to record 80% of the deer in an area within this buffer distance (Jacobson et al. 1997). ...
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Capture and handling of animals is an essential component of wildlife research. Human population growth, coupled with rapid land use changes, have resulted in increased wildlife‐human interactions and subsequently increased public awareness and sensitivity to animal welfare. However, few publications have compared capture techniques in terms of effectiveness, economics, and animal safety across the same environment. We evaluated capture effectiveness, monetary cost, and safety for drop nets and both single and tandem helicopters with net‐gunning techniques for white‐tailed deer (Odocoileus virginianus; deer). We captured 32 (drop nets), 68 (single helicopter), and 71 (tandem helicopters) deer over 6 study periods (3 autumn and 3 spring) from August 2011 to February 2014. Catch‐per‐unit‐effort (CPUE, person hours/deer) was lowest for tandem helicopters (2.3) followed by single helicopter (2.7) and then drop nets (65.8). Animals captured using drop nets heavily favored younger males compared to both helicopter and net‐gunning techniques. Capture cost (total cost/deer) was greater for drop nets ($655 USD) than either single helicopter ($164) or tandem helicopters ($231). Total mortality (capture‐related and postcapture myopathy) was highest for drop nets at 12.5% followed by 5.9% for single helicopter and 4.2% for tandem helicopters. While all 3 techniques were safe and effective methods for deer capture, the tandem helicopter technique was superior in balancing effectiveness, cost, safety, and maximizing spatial coverage, all of which must be considered when selecting among available capture methods. We evaluated capture effectiveness, monetary cost, and safety for drop net and both single and tandem helicopter with net‐gun techniques for white‐tailed deer. While all three techniques were safe and effective methods for deer capture, the tandem‐helicopter technique was superior in balancing effectiveness, cost, safety, and maximizing spatial coverage, all of which must be considered when selecting among available capture methods. ... Vegetative characteristics and the relatively large size of the facility did not provide an environment where it was possible to view all animals at all times; therefore, we used a combination of methods to estimate deer abundance, adult sex ratio, and age structure. We placed infrared-triggered cameras at feeders and random sites baited with corn during 14 days each February and used the collected images of marked and unmarked deer to estimate deer abundance using mark-recapture methods (Overton 1969, Jacobson et al. 1997. These data were used in conjunction with field observations, and capture and mortality records to determine final population demographic estimates. ... Article Full-text available Positive relationships between age, sexually selected traits, and male reproductive success have been reported for a number of polygynous ungulates; however, relatively little is known about the factors influencing male reproductive success in ungulate species whose mating system is characterized by tending-bond behaviors. Broad interest in the genetic consequences of selective harvest supports a greater understanding of the role of these factors as determinants of male reproductive success in important game species (e.g., white-tailed deer [Odocoileus virginianus]), that exhibit tending-bond behaviors. We investigated male reproductive success in white-tailed deer across a range of sex ratios and age structures using a known population of deer housed in a 175-ha enclosure in central Alabama, USA. We measured age, annual antler size, and annual body size of male white-tailed deer and assigned paternity to 143 known-age offspring during 2007–2014. Reproductive success was attributed to a high proportion of males during each of the 6 breeding seasons. Our most supported model indicated that annual body size and antler size of the individual were positively associated with annual male breeding success. The effects of annual antler size were sensitive to changes in mean male age of the herd, with antler size having the greatest effect on male reproductive success under older male age structures. Young (≤1.5 yr) males reproduced most frequently when male age structure was youngest (which correlated with female-biased sex ratios in this population). Our results suggest that male age structure and sex ratio played a key role in establishing patterns of male reproductive success in white-tailed deer. Management practices that encourage balanced adult sex ratios and older male age structures (e.g., Quality Deer Management) may promote a highly competitive environment where sexually selected traits are of increased importance to male breeding success. However, the ability of managers to alter herd genetics in a positive or negative direction through selective harvest is limited in white-tailed deer because of the high proportion of reproducing males. ... Few, if any, species have had more work focused on population size estimation and methodological evaluation than the white-tailed deer (Odocoileus virginianus; hereafter, deer; Gill et al. 1997, Lancia et al. 2005, Collier et al. 2013. A variety of survey techniques have been developed for estimating deer population size: browse surveys (Aldous 1944, Tremblay et al. 2005, harvest data reconstruction (Roseberry andWoolf 1991, Millspaugh et al. 2009), pellet counts (Eberhardt and Van Etten 1956, Van Etten and Bennett 1965, ground-based infrared and thermal imaging surveys (Wiggers and Beckerman 1993, Gill et al. 1997, Collier et al. 2007, spotlight surveys (McCullough 1982, Mitchell 1986, DeYoung 2011, and camera surveys (Jacobson et al. 1997, Koerth andKroll 2000) among others. However, aerial surveys remain the best option for counting large mammals, especially over large areas (Caughley 1974, Jachmann 1991, Linchant et al. 2015. ... Article Full-text available Drones equipped with thermal sensors have shown ability to overcome some of the limitations often associated with traditional human‐occupied aerial surveys (e.g., low detection, high operational cost, human safety risk). However, their accuracy and reliability as a valid population technique have not been adequately tested. We tested the effectiveness of using a miniaturized thermal sensor equipped to a drone (thermal drone) for surveying white‐tailed deer (Odocoileus virginianus) populations using a captive deer population with a highly constrained (hereafter, known) abundance (151–163 deer, midpoint 157 [87–94 deer/km2, midpoint 90 deer/km2]) at Auburn University's deer research facility, Alabama, USA, 16–17 March 2017. We flew 3 flights beginning 30 minutes prior to sunrise and sunset (1 morning and 2 evening) consisting of 15 nonoverlapping parallel transects (18.8 km) using a small fixed‐wing aircraft equipped with a nonradiometric thermal infrared imager. Deer were identified by 2 separate observers by their contrast against background thermal radiation and body shape. Our average thermal drone density estimate (69.8 deer/km2, 95% CI = 52.2–87.6), was 78% of the mean known value of 90.2 deer/km2, exceeding most sighting probabilities observed with thermal surveys conducted using human‐occupied aircraft. Thermal contrast between animals and background was improved during evening flights and our drone‐based density estimate (82.7 deer/km2) was 92% of the mean known value. This indicates that time of flight, in conjunction with local vegetation types, determines thermal contrast and influences ability to distinguish deer. The method provides the ability to perform accurate and reliable population surveys in a safe and cost‐effective manner compared with traditional aerial surveys and is only expected to continue to improve as sensor technology and machine learning analytics continue to advance. Furthermore, the precise replicability of autonomous flights at future dates results in methodology with superior spatial precision that increases statistical power to detect population trends across surveys. © 2020 The Wildlife Society. Drones equipped with thermal sensors have shown ability to overcome some of the limitations often associated with traditional human‐occupied aerial surveys (e.g., low detection, high operational cost, human safety risk); however, their accuracy and reliability as a valid population technique have not been adequately tested. We tested the effectiveness of using a drone equipped with a nonradiometric thermal infrared imager for surveying a captive deer population with a known abundance and observed the ability to conduct precisely replicated surveys with sighting probabilities (92% during optimized flight conditions) that equal or exceed traditional airborne techniques. ... Motion-sensitive cameras have revolutionized the study of wildlife (Nichols and Karanth 2011, Burton et al. 2015, Glover-Kapfer et al. 2019, and were first used to estimate deer abundance in 1992 (North America: Jacobson et al. 1997). This method has increasingly been used to estimate deer abundance and density in all regions except Australasia (Figure 2), reflecting a more general uptake of motion-sensitive cameras to study wildlife (Burton et al. 2015, Glover-Kapfer et al. 2019). ... Article Full-text available Deer are key components of many ecosystems and estimating deer abundance or density is critical to understanding these roles. Many field methods have been used to estimate deer abundance and density, but the factors determining where, when, and why a method was used, and its usefulness, have not been investigated. We systematically reviewed journal articles published during 2004–2018 to evaluate spatio‐temporal trends in study objectives, methodologies, and deer abundance and density estimates, and determine how they varied with biophysical and anthropogenic attributes. We also reviewed the precision and bias of deer abundance estimation methods. We found 3,870 deer abundance and density estimates. Most estimates (58%) were for white‐tailed deer (Odocoileus virginianus), red deer (Cervus elaphus), and roe deer (Capreolus capreolus). The 6 key methods used to estimate abundance and density were pedestrian sign (track or fecal) counts, pedestrian direct counts, vehicular direct counts, aerial direct counts, motion‐sensitive cameras, and harvest data. There were regional differences in the use of these methods, but a general pattern was a temporal shift from using harvest data, pedestrian direct counts, and aerial direct counts to using pedestrian sign counts and motion‐sensitive cameras. Only 32% of estimates were accompanied by a measure of precision. The most precise estimates were from vehicular spotlight counts and from capture–recapture analysis of images from motion‐sensitive cameras. For aerial direct counts, capture–recapture methods provided the most precise estimates. Bias was robustly assessed in only 16 studies. Most abundance estimates were negatively biased, but capture–recapture methods were the least biased. The usefulness of deer abundance and density estimates would be substantially improved by 1) reporting key methodological details, 2) robustly assessing bias, 3) reporting the precision of estimates, 4) using methods that increase and estimate detection probability, and 5) staying up to date on new methods. The automation of image analysis using machine learning should increase the accuracy and precision of abundance estimates from direct aerial counts (visible and thermal infrared, including from unmanned aerial vehicles [drones]) and motion‐sensitive cameras, and substantially reduce the time and cost burdens of manual image analysis. A minority of deer abundance and density estimates were accompanied by a measure of precision, and bias was seldom evaluated. The usefulness of deer abundance and density estimates would be substantially improved by reporting key methodological details, robustly assessing bias, using methods that increase detection probability, and reporting the precision of estimates. ... However, the issue of individual animal recognition has frequently been a concern, with many researchers attempting to find ways to distinguish their study species through the assignation of more temporary features such as scars (Trolle et al 2008, Oliveira-Santos et al 2010, body condition (Kelly et al 2008) and single sex characteristics e.g. antler structure (Jacobson et al 1997) but as these are not permanent or unique features overestimation of densities may arise (Foster and Harmsen 2012). ... Thesis Full-text available Camera traps have taken off one of the most popular tools in ecology. This thesis aims to develop existing camera trap methodology in order to better assess the distribution and abundance of deer in the UK. Particular focus was made on the invasion history of muntjac to help elucidate their invasion pattern. The number of founding females was estimated to be 4 or 5 individuals. The effect of covariates on the camera detection zones were considered to help improve density estimates resulting from camera trap research. Flash type and individual passing speed proved to be two important covariates adding weight to the recommendation that camera detection zones should be survey specific and that activity patterns should be considered when determining detection zones. Eight deer population densities were estimated from across the UK using both thermal imaging distance sampling and random encounter model (REM) techniques. A higher density was found with the REM, thought the two methods appeared more comparable in open woodlands. A low quality thermal imagine camera may have bias the results, but this study also emphasises the need to ensure other parameters, such as daily travel distance are site specific and as accurate as possible. Muntjac sightings, within Northern Ireland, were collated and verified using a scoring system and survey combination. The REM was trialled in one site, finding a minimum population of 5 muntjac deer. This baseline result can be used in any future population monitoring. These verified sightings alongside others from Ireland were used to test a muntjac species distribution model with different sampling bias approaches. The random background model was the most parsimonious model suggesting, in this case, that the additional bias controlling techniques may not always be necessary. ... To estimate abundance and age structure of our white-tailed deer population, images of marked and unmarked deer were collected using infrared-triggered cameras at both feeders and randomly selected sites baited with corn for 14 days every February. These images were then used to calculate deer abundance using mark-recapture methods (Overton 1969;Jacobson et al. 1997). We supplemented these data with field observations and capture/ mortality records to determine final population demographic estimates. ... Article Full-text available Body size and secondary sexual characteristics are drivers of male reproductive success among polygynous species. A gene complex found to be associated with morphology in several species is the major histocompatibility complex (MHC). However, while several studies have found that greater MHC diversity is associated with larger body size and secondary sexual characteristics, other studies have demonstrated that maximal MHC diversity is not always optimal for the individual’s fitness. This study tested if MHC diversity, measured as pairwise allelic distances at each of two unlinked MHC II loci (exon 2 for the classical antigen-binding protein MHC-DRB and exon 2 for the accessory protein MHC-DOB), was associated with body size (male and female) or antler size in a semi-wild enclosed population of white-tailed deer (Odocoileus virginianus). After accounting for the effect of age on body and antler size, we used residual analysis to assess whether MHC allelic distances explained any of the remaining variation in body and antler size. While we found no associations between physical characteristics and MHC-DRB, we found that both male body and antler size were associated with MHC-DOB nucleotide allelic distances. Specifically, we found a quadratic relationship between MHC-DOB and male body size, where body size peaked at moderate MHC-DOB nucleotide allelic distance. However, we found a positive linear association between MHC-DOB nucleotide allelic distances and antler size. Neither MHC-DRB nor MHC-DOB influenced female body size, even though the average allelic distances of males and females were not significantly different. Our results suggest that MHC-DOB, or a gene genetically linked to this locus, may influence male morphological characteristics in white-tailed deer. ... We deployed 100 camera traps (Reconyx [model PC800], Holmen, WI) at a density of 1 per 500 hectares during August 2011-2013. Following Jacobson et al. ( [43]; designed to survey deer), we used 14-day pre-baiting and survey periods, and we set cameras to a 3-min delay between photographs. For each image, we recorded the number, age (juvenile or adult), and vigilance level of raccoons, as well as the time and date, presence of other wildlife species, and the moon phase. ... Article Full-text available Nonconsumptive effects of predators potentially have negative fitness consequences on prey species through changes in prey behavior. Coyotes (Canis latrans) recently expanded into the eastern United States, and raccoons (Procyon lotor) are a common mesocarnivore that potentially serve as competitors and food for coyotes. We used camera traps at baited sites to quantify vigilance behavior of feeding raccoons and used binomial logistic regression to analyze the effects of social and environmental factors. Additionally, we created raccoon and coyote activity patterns from the camera trap data by fitting density functions based on circular statistics and calculating the coefficient of overlap (∆). Overall, raccoons were vigilant 46% of the time while foraging at baited sites. Raccoons were more vigilant during full moon and diurnal hours but less vigilant as group size increased and when other species were present. Raccoons and coyotes demonstrated nocturnal activity patterns, with coyotes more likely to be active during daylight hours. Overall, raccoons did not appear to exhibit high levels of vigilance. Activity pattern results provided further evidence that raccoons do not appear to fear coyotes, as both species were active at the same time and showed a high degree of overlap (∆ = 0.75) with little evidence of temporal segregation in activity. Thus, our study indicates that nonconsumptive effects of coyotes on raccoons are unlikely, which calls into question the ability of coyotes to initiate strong trophic cascades through some mesocarnivores. ... More available and widespread devices are triggered trail cameras that are used for moose and other wildlife research to study their activity and behaviour (Foster andHumphrey 1995, Main andRichardson 2002) or to estimate population size (Jacobson et al. 1997, Sweitzer et al. 2000, Roberts et al. 2006) and for other wildlife studies. It is an advantage of camera traps to work independently of observers and storage data within battery lifespan. ... Research Full-text available Without human intervention, wildlife including moose can increase in numbers up to marked overpopulation followed by disease, starvation and damage caused to forestry. Although nature has its own ways of controlling wildlife populations, these ways could be much less humane that modern hunting. Population management decisions include appropriate harvest levels, timing of hunting seasons, habitat carrying capacity and habitat management practices. We have queried publications and internet-based resources to determine the moose population dynamics and changes predicted for different habitats and conditions. The existing population management models and methodology were analysed. ... We excluded counts during May in each year because of the difficulty of distinguishing between calves and adult cows. During analysis, we excluded photos if one or more of the individuals in the photo could not be confidently identified to age or sex (Jacobson et al. 1997;McCoy et al. 2011). Using photos from camera traps to estimate age-and sex-ratios assumes equal detection among the age-and sexclasses. ... Article Mule deer (Odocoileus hemionus) survival and population growth in north-central New Mexico, USA, was previously reported to be limited by nutritional constraints due to poor forage conditions in degraded habitats. Management recommendations suggested thinning of pinyon-juniper to improve habitat quality for mule deer. To evaluate the influence of these vegetation treatments, we monitored habitat selection by 48 adult female mule deer from 2011 to 2013 in a population previously reported to be nutritionally limited. Monitoring occurred 1-4 years after completion of treatments that were intended to improve forage conditions, including mechanical reduction of pinyon pine (Pinus edulis) and juniper (Juniperus spp.) density and senescent brush (Quercus gambelii-Cercocarpus montanus) cover. During the summer season, deer selected recently treated areas, but odds ratios decreased with treatment age. However, during winter, deer avoided more recently treated areas and selected thinned areas >4 years old. Deer selected mixed oak (Quercus spp.) and pinyon-juniper savanna vegetation cover types with a moderately open canopy and ponderosa pine (Pinus ponderosa) forests while avoiding grasslands and montane shrub-lands across all seasons. Deer selected areas closer to water and developed areas, northeast aspects, on gentle slopes, and at lower elevations. Creating a savanna-like cover type may elicit a positive deer response as a result of their strong avoidance of dense, closed canopy pinyon-juniper woodlands. ... In Mississippi, 92% and 89% of marked male and female white-tailed deer, respectively, were recaptured on camera (McKinley et al. 2006). Additionally, Jacobson et al. (1997) photographed 100% and 88% of individually marked deer over a 2 yr period in Texas. In our study, there was a moderately strong correlation between acaricide levels of captured deer and the number of photos at bait sites for the same deer, indicating that motion-triggered cameras were a good measure of deer visitation to bait sites and subsequent exposure to medications. ... Article Full-text available White-tailed deer ( Odocoileus virginianus) serve as a host for cattle fever ticks ( Rhipicephalus [ Boophilus] microplus and R. [ B.] annulatus; CFTs); therefore, deer are a concern for CFT control programs in southern Texas. Systemic (oral delivery of ivermectin) and topical (permethrin on pelage) treatment devices have been developed for white-tailed deer; however, the efficacy of these treatment options has not been determined for CFTs in southern Texas. Our objectives were to evaluate the effectiveness of CFT treatment strategies by 1) measuring exposure rates of deer to the acaricides permethrin and ivermectin, 2) determining the relationship between CFTs on deer and exposure to the acaricides, and 3) determining if photos from remote cameras at medicated bait sites can be used as a measure of acaricide treatment. We captured 327 deer at four sites in southern Texas. Deer visitation to medicated bait sites was monitored using remote cameras from March 2010 to February 2012. There was no relationship between the presence of permethrin and the probability of being infested with CFTs ( P≥0.336). The probability of infestation with CFTs decreased as serum ivermectin levels increased for male ( n=18, P=0.098) and female ( n=33, P<0.001) deer. Our results indicate ivermectin may be more effective in treating CFTs than permethrin; thus it would be worthwhile to develop topical acaricides other than permethrin for treating white-tailed deer in southern Texas. ... Deer population density on RTMSP in January 2004 was estimated at 36 deer/km 2 , based on mark-resight surveys using in-frared cameras (Jacobson et al. 1997, Killmaster 2005. During February-March 2004, sharpshooters from the U.S. Department of Agriculture's Wildlife Services reduced the population to about 10 deer/km 2 by shooting any deer not wearing a radiocollar (as described below). ... Article Full-text available Effects of traffic volume on white-tailed deer (Odocoileus virginianus) movement patterns and behavior have not been well documented. During summer 2004, we monitored survival and home ranges of 34 radiocollared deer (6 males and 28 females) in a heavily visited state park in Georgia to determine effect of road distribution on home range use. We also monitored hourly movements for eight females in relation to daily patterns of vehicle volume within the park. Although deer behavior was altered by frequent exposure to traffic and roadside feeding of deer by park visitors, no deer were killed by vehicles during the study. Deer did not selectively use habitats within their home ranges based on proximity of nearest roads. We found no differences (P > 0.05) in deer distances from nearest roads during any 24-hr period. Mean rate of travel for the eight females increased (P < 0.001) when mean traffic volume within the park increased (1400−2000 hours) and decreased when traffic volume decreased (2000−0200 and 0200−0800 hours), suggesting park vehicles had a disruptive effect on deer movements. ... e.g.,McKinley et al. 2006;McCoy et al. 2011) and have allowed for the identification of some temporal developmental phases such as the presence of offspring, pregnant females, and the moment in which the hard antlers of the males become apparent (e.g.,McKinley et al. 2006;Soria- Días and Monroy-Vilchis 2015). Some studies have even made possible the identification of individual males based on antler configurations(Jacobson et al. 1997).From 2010 to 2017, we performed 10 camera trap surveys along in the wetlands of southwestern Campeche with the aim of determining the richness and abundance of medium-sized and large mammals of the study area (see Hidalgo-Mihart et al. 2017 for a review). The location, intensity, and timing of the surveyed areas were established according to the information required by the managers of the natural protected areas in the region. ... Thesis The white-tailed deer is the most hunted species in the tropics of Mexico. However, information on daily movements, the size of the home environment, as well as the seasonality of antlers and times of birth in tropical sites is scarce. In this study we analyzed the factors that influence the daily distances travelled, the size of the home environment and the temporality of antlers and fawning of the white-tailed deer distributed in southeastern Mexico between the states of Tabasco and Campeche. Using satellite telemetry data, daily movement data were obtained, as well as the area of deer activity. Using trap camera data, the timing of antlers and the time of fawning of white-tailed deer were analyzed. We found that the daily movements of the white-tailed deer in the study area are less than reports from studies in central and northern Mexico. Movements recorded are longer during the dry season and shorter during the wet season. Similarly, the home environment recorded in this study was similar to that recorded in other tropical sites for the species but differs from home environments recorded in sites where animals were translocated or reintroduced. Physical factors such as temperature did not show any influence on daily movements, but food scarcity is likely to include the time of birth, as well as longer daily movements of deer. In addition, the results indicate that the breeding season in the Campeche wetlands is different from that in the northern latitudes of Mexico and the southern United States. It was found that the timing of the development of hard white-tailed deer antlers in the study area does not coincide with the official hunting season established in Mexico. Article Full-text available Individuals may reduce competition by temporally partitioning their use of a shared resource. Behavioral differences between sexes in ungulates may encourage segregation as individuals attempt to avoid antagonistic interactions. However, dominant sex and age groups may reduce subordinates’ access to food resources, regardless of the subordinate’s sex. We hypothesized that white-tailed deer Odocoileus virginianus temporally segregated at supplemental feeding sites based on social rank (subordinate: yearling males and adult females; dominant: adult males) and that segregation was affected by phase of the breeding season and diel cycle. If deer temporally segregate according to social rank, we predicted that the resulting activity patterns would manifest in one social class being relatively more susceptible to hunter-induced mortality. We used a multi-state modeling approach to quantify temporal segregation and calculated the probability that a feeding site was in a particular state during diurnal and nocturnal hours during the 3 phases of the breeding season. We determined that transition probabilities differed by season and diel cycle and dominant and subordinate social classes clearly avoided each other, with < 1% co-occurrence at feeding sites. During the pre-breeding season, the probability of a subordinate being present during diurnal hours was 3.0x more likely than a dominant being present, but did not differ during nocturnal hours. There was no difference for dominants and subordinates during diurnal or nocturnal hours during the breeding season. In the post-breeding season, subordinates were 1.7x more likely to occur at the feeding site than a dominant during diurnal hours but they did not differ during nocturnal hours. Our results indicate that dominance status influences temporal segregation at feeding sites and is affected by the phase of the breeding season. Therefore, the resulting activity patterns may increase subordinates’ risk to human predation during the pre-breeding and post-breeding seasons. Article Camera traps are widely used to monitor wildlife, with important management decisions often relying on interpretation of these data. Animal misidentifications are known to be an important source of error in wildlife surveys that require the identification of unique individuals from camera‐trap data; however, the practice of broadly classifying animal images according to sex or age has received less critical attention despite the significant potential for misidentification error under certain circumstances. From 19 January to 1 April 2017, we solicited a group of 726 participants, consisting of both wildlife professionals and nonprofessionals from across the United States, to take an online survey that tested their ability to classify images of known white‐tailed deer (Odocoileus virginianus) according to sex and age. Our goal was to determine the relative influence of tested observer (i.e., experience and familiarity with classifying deer images) and image‐based factors (i.e., distance of deer from camera, day vs. night image) on accuracy of deer classifications. Our results indicated that respondents that were wildlife biologists and those with greater levels of experience viewing deer images were more accurate than others when classifying posthunting season images of deer as adult male, adult female, or fawn. However, the sex–age group of the deer was the most influential predictor of classification reliability, with branched‐antlered adult males being classified more accurately by all respondent groups than were adult females and fawns. Our findings emphasized that animal misidentifications may be an important source of survey error not only when identifying unique individuals, but also under any circumstance where comparative groups lack definitive traits. We suggest that those using camera traps to evaluate wildlife populations should select survey periods that maximize differences among classification groups, when possible, and develop species‐specific image training for observers to improve the reliability of results. Further, population demographics should be considered when evaluating the overall reliability of survey results for species where classification accuracy varies among sex–age groups. Animal misidentifications are known to be a source of error in wildlife evaluations that use camera trap data; however, little is known regarding the specific factors contributing to these types of error. We found that both observer experience and the physical characteristics of the target animal were important determinants of accuracy when classifying white‐tailed deer images. Article U provedenom istraživanju pokušalo se istražiti u kojoj mjeri je moguće aplicirati sustav bespilotne letjelice opremljene termalnom kamerom u procjeni nekih populacijskih parametara krupne divljači. Istraživanje je provedeno u nizinskom području kontinentalnog dijela Republike Hrvatske unutar lovišta Opeke II. Za istraživanje je odabrana divlja svinja kao najčešća vrsta krupne divljači u Republici Hrvatskoj. Unutar dva lokaliteta (I dobni razred,uređajni razred hrasta lužnjaka) provedeno je testiranje dvije metode prebrojavanja. Prvom metodom pokušala su se prebrojiti sva grla unutar istraživanog odsjeka. Rezultati dobiveni tom metodom pokazuju relativno visoku brojnost divlje svinje od prosječno 1,26 +/– 0,18 grla/ha unutar istraživanjem obuhvaćenog područja. Druga korištena metoda predstavlja prebrojavanje divljih svinja na unaprijed određenim prugama, čiji udio u ukupnoj promatranoj površini iznosi 10%. Kod te metode podaci su veće varijabilnosti te je ustanovljena nešto manja brojnost divljih svinja unutar promatranog odsjeka od 0,61 grla/ha uz vrlo visok sd= +/– 0,53. Istraživanjem je potvrđena mogućnost primjena sustava bespilotnih letjelica s termalnim kamerama. Od dvije primijenjene metode, prva (apso­lutno prebrojavanje svih životinja) je pogodna za manje površine, dok je metoda primjernih pruga pogodna za veće površine uz svjesni rizik generiranja veće pogreške prebrojavanja. 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Meanwhile, along with improvements in techniques, decreasing cost and increasing application interests, camera-trapping will be adopted by more researchers, wildlife managers and protected areas, and can be used for systematic wildlife monitoring using standard protocols. Efforts devoted to its future development and applications should focus on establishing systematically designed monitoring networks and data-sharing protocols, and developing new analytical approaches and statistical models specifically based on camera-trapping data. Article Bottomland hardwoods forests (BLHW) are increasingly subject to active management for water quality improvement, streambank stabilization, to mitigate for urban expansion and to improve habitat for wildlife. Since the majority of remaining BLHW are degraded, restoration attempts are becoming commonplace within the Western Gulf Coastal Plain (WGCP) of the US. However, restoration success in terms of obtaining high stem densities of desirable species has been mixed, with managers observing survival rates <15 per cent for planted oak and hickory seedlings in some situations due to a variety of limitations. Over two growing seasons, we investigated the effectiveness of portable electric fences, individual tree shelters and 2.4-m woven wire high fences for mitigating herbivory by white-tailed deer (Odocoileus virginianus) and feral swine (Sus scrofa). Treatments fell within degraded forested areas and abandoned agricultural fields where we tested four species of interest: Nuttall oak (Quercus texana Buckley), Shumard oak (Q. shumardii Buckley), bur oak (Q. macrocarpa Michx.) and pecan (Carya illinoinensis K. Koch). Where herbivory occurred, mitigation techniques produced a higher survival rate ($\bar{\rm{X}} $= 17.6 per cent) than unprotected areas ($\bar{\rm{X}} $= 9.1 per cent). In areas of high white-tailed deer density, prominent browsing was evident, resulting in two-growing-season height growth of seedlings being less in non-fenced ($\bar{\rm{X}} $= 2.33 cm) and electric ($\bar{\rm{X}} $= 4.33 cm) fenced plots compared with high fences ($\bar{\rm{X}} $= 13.02 cm) and individual tree shelters ($\bar{\rm{X}} \$ = 24.23 cm). Additionally, we observed a negative relationship between survival and the number of days seedlings that were inundated with flood waters during the growing season. Matching species of interest to the site conditions, specifically the local hydrologic regimes, should carry a high priority in planning a restoration project within BLHW in the WGCP.
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The population status of the IUCN vulnerable Nubian Ibex Capra nubiana is largely unknown in the Middle East because of difficulties conducting intensive surveys. We tested the utility of camera-trapping at permanent water sites to estimate demographics and population trend of the species in the Dana Biosphere Reserve, Jordan. We also studied the relationship between precipitation and the Normalized Difference Vegetation Index NDVI on water site use by the Nubian Ibex, demographics, and population trend. The Nubian Ibex showed a mean annual productivity of 0.81 neonate/female and an adult female survival of 0.87 which is a lower survival rate than found in other ibex species. The mean potential annual rate of increase of this population (λ=1.14) was similar to those reported from other ibex species and indicated a viable population. The capture rate of camera traps (number of photographed animals/camera day) was found not to be a reliable index to monitor population trends because water site use was related to environmental conditions that could not be standardized or predicted a priori. Quantifying population demographic ratios using camera trapping allowed for monitoring the status of key population parameters and growth potential of Nubian Ibex populations in the Dana Reserve, and likely can be used to monitor population status and facilitate informed management of similar populations in the Middle East.
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Integrating Global Positioning System (GPS) technology with expandable collars will allow researchers to more accurately and efficiently investigate survival of white‐tailed deer (Odocoileus virginianus) fawns. We tested fit and function of 5 expandable GPS collar prototypes on white‐tailed deer fawns and conducted behavioral observations during the first 12 weeks of life at the Whitehall Deer Research Facility, Athens, Georgia, USA, during 2018–2020. We fitted 46 fawns with 5 prototype collar designs and ear‐tagged 15 control fawns without collars. Prototype collars differed in expandable band materials. Premature expansion and breakage of collar bands composed of cotton and rubber was a problem that resulted in freely moving collars and displacement to the waist of fawns. Fawns retained prototype collar designs with cotton and rubber band materials for a mean 101 (±46 [SD]) and 70 (±37) days, respectively. For 2 collar designs with expandable bands composed of nylon and rubber, fawns retained collars for a mean 246 (±156) and 306 (±99) days, respectively. Vectronic (v1.0 and v2.0; VECTRONIC Aerospace GmbH, Berlin, Germany) and Telonics v2.0 (Telonics Inc., Mesa, AZ, USA) collared fawns were 16–21% less likely to be observed standing compared to uncollared fawns. Bedded Vectronic (v1.0 and v2.0) and Telonics v2.0 collared fawns were 19–28% less likely to be observed with their head up compared to uncollared fawns. Bedded fawns with collars were 11–16% more likely to be observed with their head tilted compared to bedded fawns without collars. Vectronic (v1.0 and v2.0) and Telonics v2.0 collared fawns were 25–34% less likely to exhibit vigilance compared to uncollared fawns, and all collared fawns were 22–37% more likely to exhibit sleeping than uncollared fawns. We recommend that GPS collar designs we evaluated undergo additional modifications before deployment in the field, including improved stitching patterns and threads to facilitate more gradual collar expansion, smaller battery housings and improved weight distribution to mitigate behavioral concerns, and smaller band circumferences to improve collar fit across time. We recommend that GPS collar designs for neonatal white‐tailed deer undergo additional modifications before deployment in the field, including improved stitching patterns and threads to facilitate a more gradual collar expansion, smaller battery housings and improved weight distribution to mitigate behavioral concerns, and smaller band circumferences to improve collar fit across time. We propose implementation of iterative processes in collar design, including a preliminary Phase I that utilizes captive animals to test initial collar designs, a subsequent Phase II that incorporates modifications to initial collar designs and further testing in captivity, and Phase III as a limited pilot deployment in a field study.
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Several subspecies of wild turkey (Meleagris gallopavo) are managed throughout the western USA for wildlife viewing and hunting, including Merriam's (M. g. merriami), Rio Grande (M. g. intermedia), eastern (M. g. silvestris), and Gould's (M. g. mexicana) wild turkey. In addition to the variety of subspecies, the West also comprises a wide variety of occupied vegetative communities throughout an array of state and federal jurisdictions. In 1993, the Colorado Division of Wildlife published the Management Guidelines for Merriam's Wild Turkeys (Hoffman et al. 1993). Since that time, harvest and monitoring methods have evolved. Harvests are monitored through mandatory or voluntary phone surveys, online surveys, mail surveys, email surveys, mobile phone applications, field checks, and wing or foot collections. Populations are monitored through harvest indices, summer brood surveys, winter flock counts, winter classifications, summer classifications, presence‐absence surveys, camera traps, forward‐looking infrared, aerial surveys, telemetry, weather indices, citizen science reports, and a variety of modeling approaches. We provide a limited review highlighting the substantive strengths and challenges associated with each population monitoring technique to provide agencies and organizations involved in monitoring harvest and populations of turkeys with an overview to assist in selecting appropriate tools for use in their jurisdiction. Although many methods exist to monitor harvests and populations of western wild turkeys, not all methods are equally powerful, sensitive, or cost effective. We provide a general overview of the substantive strengths and challenges associated with techniques commonly employed by managers, building on the guidance provided by Hoffman et al. (1993). Monitoring harvest and populations of western wild turkeys is important for successful management programs. Photo courtesy of Brian Wakeling
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Radio-collared white-tailed deer (Odocoileus virginianus; 7 males, 13 fe-males) were tracked from 1984 to 1989 on the Marion County Wildlife Management Area in southern Mississippi. Alternating halves of the study area were planted with 66 0.1-ha and 20 0.4-ha cool-season and 20 0.4-ha summer agronomic forage plots. Mean annual production and utilization (air-dry) of cool-season forages were 1,904 kg/ha (SE = 59) and 1,107 kg/ha (SE = 41), respectively. Summer forage production and utilization were 664 kg/ha (SE = 50) and 586 kg/ha (SE = 48), respectively. Annual 95% convex polygon home ranges averaged 691 ha for 6 adult (> 3 years) bucks and 343 ha for 12 adult does. Significant (P < 0.05) seasonal differences in home range size were observed for does, but seasonal differences for bucks were not significant (P = 0.12). Significant movements both toward and away from the planted side of the study area were observed for some individual deer. Net movement of radio-collared deer, however, did not respond positively or negatively to the planting of food plots. Food plots in the Southeast have been commonly used in wildlife habitat management since 1935 (Halls and Stransky 1969, Larson 1969). While many re-searchers have demonstrated the high degree to which deer utilize agronomic food plots (Handly and Scharnagel 1961, Webb 1963, Johnson et al. 1987, Davis 1988), little research has been done to document their effects on deer movements. Brown and Mandery (1962) reported that fertilized agronomic forages would at-tract and hold elk from considerable distances. Byford (1970) related an account of a radio-tracked doe changing her center of activity 4 times in several months, presumably in response to changing food availability. Mott et al. (1985) reported that deer appeared to shift their geometric center of use toward soybean fields 'Present address: Florida Game and Fresh Water Fish Commission, Joe Budd Wildlife Field Office, Route 7, Box 3055, Quincy, FL 32351.
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A method is presented for estimating population size from index data collected before and after removal of a known number of individuals. An approximate variance estimate is given and used to delineate circumstances where the method may be useful. Confidence limits are obtained from Fieller's method and illustrated with data from feral horse (Equus caballus) herds. A comparison with the use of marking is provided.
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White-tailed deer (Odocoileus spp.) overpopulate many areas of the United States. Browse damage to agricultural crops, forest regeneration and landscaping can be severe. Human and animal health also are threatened by Lyme disease, which is spread by the deer tick (Ixodes dammini). Although sterilants to reduce and/or slow the growth of deer populations and vaccines against Lyme disease may soon become available, efficient and economical techniques to inoculate large numbers of deer have not been developed. Oral baits represent one promising possibility. In experiment 1, salt blocks and several olfactory lures were evaluated as potential lures for use in deer baits. Plain salt blocks were attractive and odour stimuli such as acorn, apple and peanut butter significantly enhanced effectiveness. Apple was the best stimulus in an old field; peanut butter and acorn were the best stimuli in a bottomland habitat. In experiment 2, blocks of minerals, salt, molasses, and mineral-molasses were presented; all were scented with apple extract. Mineral blocks were the most attractive, followed by salt blocks and mineral-molasses blocks; molasses blocks were the least attractive. In experiment 3, mixtures of apple, acorn and peanut butter extracts were presented with mineral blocks. None of the combinations was more attractive than the others and none was more attractive than mineral blocks presented with apple extract only.