Deer Mortality Research Articles

EPIZOOTIOLOGY OF CRANIAL ABSCESS DISEASE IN WHITE-TAILED DEER (ODOCOILEUS VIRGINIANUS) OF GEORGIA, USA.

Intracranial abscess disease is a cause of natural mortality for mature male white-tailed deer (Odocoileus virginianus). Most cases of abscesses are associated with bacterial infection by Trueperella (Arcanobacterium) pyogenes, but a complete understanding of the epidemiology of this disease is lacking. We quantified the effects of individual characteristics, site-specific herd demographics, land cover, and soil variables in estimating the probability of this disease. We examined 7,545 white-tailed deer from 60 sites throughout Georgia US for signs of cranial abscesses, the predecessor of intracranial abscesses, and recorded the presence or absence of cranial abscesses for each individual examined. We detected no cranial abscesses in 2,562 female deer but 91 abscesses in 4,983 male deer examined (1.8%). A generalized linear mixed model, treating site as a random effect, was used to examine several potential explanatory risk factors including site-level landscape and soil characteristics (soil and forest type), demographic factors (deer density and male to female ratio), and individual host factors (deer sex and age). Model results indicated that the probability of a male having a cranial abscess increased with age and that adult sex ratio (male:female) was positively associated with this disease. Site-specific variables for land cover and soil types were not strongly associated with observations of the disease at the scale measured and a large amount of among-site variability remained. Given the demonstrated effect of age, gender, and local sex ratios but the remaining unexplained spatial variability, additional investigation into spatiotemporal variation of the presumed bacterial causative agent of cranial abscesses appears warranted.

Large impact of Eurasian lynx predation on roe deer population dynamics.

The effects of predation on ungulate populations depend on several factors. One of the most important factors is the proportion of predation that is additive or compensatory respectively to other mortality in the prey, i.e., the relative effect of top-down and bottom-up processes. We estimated Eurasian lynx (Lynx lynx) kill rate on roe deer (Capreolus capreolus) using radio-collared lynx. Kill rate was strongly affected by lynx social status. For males it was 4.85 ± 1.30 S.E. roe deer per 30 days, for females with kittens 6.23 ± 0.83 S.E. and for solitary females 2.71 ± 0.47 S.E. We found very weak support for effects of prey density (both for Type I (linear) and Type II (non-linear) functional responses) and of season (winter, summer) on lynx kill rate. Additionally, we analysed the growth rate in a roe deer population from 1985 to 2005 in an area, which lynx naturally re-colonized in 1996. The annual roe deer growth rate was lower after lynx re-colonized the study area, but it was also negatively influenced by roe deer density. Before lynx colonized the area roe deer growth rate was λ = 1.079 (± 0.061 S.E.), while after lynx re-colonization it was λ = 0.94 (± 0.051 S.E.). Thus, the growth rate in the roe deer population decreased by Δλ = 0.14 (± 0.080 S.E.) after lynx re-colonized the study area, which corresponded to the estimated lynx predation rate on roe deer (0.11 ± 0.042 S.E.), suggesting that lynx predation was mainly additive to other mortality in roe deer. To conclude, this study suggests that lynx predation together with density dependent factors both influence the roe deer population dynamics. Thus, both top-down and bottom-up processes operated at the same time in this predator-prey system.

Epethelial presence of Trueperella pyogenes predicts site-level presence of cranial abscess disease in white-tailed deer (Odocoileus virginianus).

Cranial/intracranial abscess disease is an emerging source of significant mortality for male white-tailed deer (Odocoileus virginianus). Most cases of cranial/intracranial abscess disease are associated with infection by the opportunistic pathogen Trueperella pyogenes although the relationship between the prevalence of the bacteria and occurrence of disease is speculative. We examined 5,612 hunter-harvested deer from 29 sites across all physiographic provinces in Georgia for evidence of cranial abscess disease and sampled the forehead, lingual, and nasal surfaces from 692 deer. We used polymerase chain reaction (PCR) to determine presence of T. pyogenes from these samples. We found T. pyogenes prevalence at a site was a predictor for the occurrence of cranial abscess disease. Prevalence of T. pyogenes did not differ between samples from the nose or tongue although prevalence along the forehead was greater for males than females (p = 0.04), particularly at sites with high occurrence of this disease. Socio-sexual behaviors, bacterial prevalence, or physiological characteristics may predispose male deer to intracranial/cranial abscess disease. Determination of factors that affect T. pyogenes prevalence among sites may help explain the occurrence of this disease among populations.

Vehicle Collisions Cause Differential Age and Sex-Specific Mortality in Mule Deer

As roads continue to be built and expanded, it is important that managers understand the effects that vehicle-related mortality can have on the population dynamics of wildlife. Our objective was to examine the frequency of mule deer (Odocoileus hemionus) vehicle collisions to determine if different demographic groups showed differential susceptibility to mortality when compared with their proportion in the population. We also compared vehicle collision rates of mule deer, elk (Cervus canadensis), and moose (Alces alces) to determine their relative vulnerability to vehicle collisions. We found that 65% of mule deer involved in vehicle collisions were female; of those, 40% were adult does ≥2 yrs. When we compared the proportion of bucks, does, and fawns killed in vehicle collisions to surveys of live deer, we found that bucks were killed at rate of 2.1–3.0 times their proportion in the population. Additionally, when we compared vehicle collision rates for 2010 and 2011, we found that mule deer were 7.4–8.7 times more likely to be involved in collisions than elk and 1.2–2.0 times more likely than moose. However, we were unable to detect a negative correlation (P=0.55) between mule deer abundance and increasing traffic volume.

Can managers compensate for coyote predation of white‐tailed deer?

ABSTRACTMany studies have documented that coyotes (Canis latrans) are the greatest source of natural mortality for white‐tailed deer (Odocoileus virginianus) neonates (<3 months old). With the range expansion of coyotes eastward in North America, many stakeholders are concerned that coyote predation may be affecting deer populations adversely. We hypothesized that declines in neonate survival, perhaps caused by increasing coyote predation, could be offset by adjusting or eliminating antlerless harvest allocations. We used a stochastic, age‐based population simulation model to evaluate combinations of low neonate survival rates, severe winters, and low adult deer survival rates to determine the effectiveness of reduced antlerless harvest at stabilizing deer populations. We found that even in regions with high winter mortality, reduced antlerless harvest rates could stabilize deer populations with recruitment and survival rates reported in the literature. When neonate survival rates were low (25%) and yearling and adult female survival rates were reduced by 10%, elimination of antlerless harvests failed to stabilize populations. Our results suggest increased deer mortality from coyotes can be addressed through reduced hunting harvest of adult female deer in most circumstances throughout eastern North America. However, specific knowledge of adult female survival rates is important for making management decisions in areas where both neonate and adult survival may be affected by predation and other mortality factors. © 2014 The Wildlife Society.

Neospora caninum is a cause of perinatal mortality in axis deer (Axis axis)

Neospora caninum is a worldwide distributed protozoan that may cause neuromuscular disease in dogs and reproductive failure in domestic and wild ruminants. One axis fawn (Axis axis) and four neonates from the same deer herd died at a zoo in Argentina within a four-month period. The fawn presented with dilatation of the anal sphincter at birth and incontinence, developed weakness and ataxia and died at 14 days of age. At necropsy, a mega formation of the distal large intestine was observed. Microscopically, non-suppurative encephalitis, suppurative bronchopneumonia, fibrin necrotic enteritis and degenerative changes in the liver were observed in hematoxilin and eosin-stained tissue sections, and thick-walled N. caninum-like cysts were observed in fresh brain samples. Serologic studies for N. caninum revealed an IFAT titer of 1:6400 in the fawn and 1:25, 1:400, 1:3200 and 1:6400 in the neonates. N. caninum DNA was detected in brain samples from the fawn and from one neonate by PCR, and the parasite was isolated in vitro from the fawn’ brain after passage through gerbils (Meriones unguiculatus) and gamma-interferon knock-out mice. N. caninum DNA obtained from the fawn, neonate and isolated parasites showed the same microsatellite pattern. This suggests a common infection source for both animals.The diagnosis of N. caninum infection was confirmed, suggesting its association with perinatal mortality in captive axis deer. To the best of our knowledge, this is the first report of clinical disease associated to N. caninum infection in axis deer and of isolation of the parasite from this wild ruminant species.

Factors Influencing Survival of White-tailed Deer Fawns in Coastal South Carolina

Abstract The social and environmental pressures exerted on white-tailed deer Odocoileus virginianus in the southeastern United States are dynamic. Understanding factors that contribute to neonatal white-tailed deer mortality is vital to population management. To determine survival rates and causes of mortality, we captured and radio-monitored neonate white-tailed deer in the coastal plain of South Carolina. Using date of birth, mass, sex, age, and year as predictor variables, we created a candidate set of survival models to evaluate which factors influenced daily survival rates. We captured and monitored 210 fawns and recorded 68 total mortalities (32.3%). We recorded few mortalities in 2006 (n = 5; 12.8%) and 2007 (n = 5; 12.5%), but we observed a significant increase in mortality in 2008 (n = 18; 37.5%), 2009 (n = 28; 53.8%), and 2010 (n = 12; 38.7%). Predation accounted for the majority of mortalities (n = 29; 42.6%). We found that male fawns were more than twice as likely to survive as females, and older fawns were more likely to succumb to predation than younger fawns. Overall survival in our study was higher than estimates recently reported in the southeastern United States. Recent increases in coyote predation have been cause for concern in some parts of the Southeast, but our results indicate that although it appeared coyote predation increased over the course of our study, predation did not reach levels that have been reported elsewhere, possibly due to predator-control activities on our study site. Close monitoring of the deer population at Brosnan Forest allowed managers to adequately adjust harvest prescriptions to maintain deer populations at the desired level despite an apparent decline in fawn survival.

Browsing of sallow (Salix caprea L.) and rowan (Sorbus aucuparia L.) in the context of life history strategies: a literature review

Sallow (Salix caprea L.) and rowan (Sorbus aucuparia L.) constitute small proportions of the deciduous tree volume in Scandinavia, but are highly preferred winter forage for moose and red deer, which occur at historically high densities. Thus, a possible decline of these tree species has been indicated. Against this background, we have reviewed the life histories of relevance for browsing, as well as the basic biology and genetics of sallow and rowan. The species show similarities with respect to short lifespan, small size and sympodial growth pattern, which are risk factors in a browsing context. They also have high juvenile growth rate, important for growing quickly out of reach of browsers. Sallow depends strongly on disturbance for establishment and is more demanding with respect to soil and light conditions than rowan, possibly important for the substantially lower abundance of sallow on the Norwegian Forest Inventory plots. Similarly, the relative recruitment of small size classes of sallow is less than for rowan. Although recruitment is reported to be hampered in wintering areas with high moose or red deer densities, the inventory data, however, dating only back to 1994, do not suggest a general decrease in any of the species. Sallow and rowan saplings show low mortality in moose and deer dominated areas and the species can be characterised as rather resilient to browsing. Of more concern is that browsing can constrain the development of mature rowan and sallow trees locally, with possible consequences for associated epiphytic biodiversity.

An Analysis of Leachate Constituents and Pathogen Destruction in Deer Mortality Static Windrow Composting

Approximately 1.1 million deer–vehicle collisions occur in the United States each year. The predominant methods of disposing of these carcasses (landfill and burial) have several costly disadvantages, including long travel distances to landfills, increasing landfill restrictions, and lack of viable burial areas. Some states have found static compost windrows to be an easy and cost-effective carcass management technique. This type of composting involves the construction of passively aerated static piles, which do not require the materials turning needed with more traditional composting methods. In this study, deer mortality static compost windrows were monitored for 1 year. Windrows were analyzed for pathogen destruction and the degree to which underlying soil filtered leachate contaminants. In response to high windrow temperatures, indicator pathogens Escherichia coli and Salmonella were reduced by 99.99 % the first sampling day (day 7) and ascarids were deemed non-viable by day 77. Soil filtration of leachate was effective in reducing concentrations of ammonia, chloride, and total organic carbon. Nitrate, a contaminant of particular regulatory concern, had an estimated mass contaminant loss of 2.1 kg/ha, compared to the estimated 9 to 50 kg/ha loss from fertilizer application of common agronomic crops. Results of this study indicate that with properly constructed static compost windrows, (1) high temperatures effectively destroy indicator pathogens; (2) the natural filtration of leachate through soil reduces deer mortality contaminant concentrations; and (3) the low volume of leachate (i.e., two percent of the precipitation that fell on windrows) results in nominal losses of nitrate and other contaminants.

An evaluation of a mitigation strategy for deer‐vehicle collisions

High mule deer Odocoileus hemionus mortality in southwestern Utah led to the establishment of a mitigation strategy with two major objectives: 1) reduction of wildlife‐vehicle collisions and 2) restoration of landscape connectivity to facilitate wildlife movement across the roaded landscape. During our study, we assessed the effectiveness of the mitigation measures in reducing mule deer mortality in the following ways: 1) we compared the number of deer‐vehicle collisions in the newly fenced area with a control area without fencing; 2) we analyzed the ‘end‐of‐the‐fence’ problem, defined here as increased mortality of mule deer at the ends of the 2.4‐m high exclusion fences; and 3) we evaluated the frequency of animal crossings of the new underpasses using remotely‐sensed cameras and compared them with crossing frequency rates for a 20‐year‐old control underpass. We compared six years of pre‐construction mortality (during 1998‐2003) with two years of post‐construction data on mortality (during 2005‐2006) and found a 98.5% decline in deer mortalities in the treatment (i.e. fenced, jump‐outs and underpasses) vs a 2.9% decline in the control (i.e. no fences, no jump‐outs and no underpasses). We detected no end‐of‐the‐fence problems related to deer mortality. Migratory movements during fall and spring were clearly reflected in the use of underpass. Overall results demonstrated that the mitigation strategy was effective and reduced the number of deer‐vehicle accidents, while allowing wildlife movement across the landscape.

Toward a reduction in tooth number: the case of P1 in roe deer from Slovenia

The permanent dentition of roe deer (Capreolus capreolus L.) comprises 30–32 teeth with the following dental formula: I 0/3, C 0/(1), P 3/3, M 3/3. Variations in tooth number and shape are rather uncommon in this species and factors determining roe deer dentition are considered to be quite stable. In both upper and lower jaws the first premolar is normally missing, but can be occasionally observed. To discover the frequency of P1 in the whole population, its occurrence was studied in the left hemi-mandibles of the total one-year (2007) roe deer mortality in Slovenia, representing a large sample set of 41,895 individuals. The first premolar was detected in only 27 individuals (13 males, 12 females, 2 without data), indicating that its occurrence is very low and sporadic (0.6‰). Furthermore, the results of previous archaeozoological and embryological studies were analyzed. On the basis of observed facts, we conclude that the first mandibular premolars of roe deer belong to a category of tooth that has been suppressed in the evolution of the Cervidae.

Factors affecting reproductive performance of white-tailed deer subjected to fixed-time artificial insemination or natural mating

The objectives of this study were to examine the effects of several factors affecting fawning rate, litter size, litter weight and neonatal fawn mortality in white-tailed deer inseminated either transcervically or by means of laparoscopy. Oestrus synchronisation with a controlled internal drug release (CIDR)-based protocol and fixed-time artificial insemination (FTAI) was conducted in 130 white-tailed deer (Odocoileus virginianus texanus) during three reproductive seasons (2007-2009; 271 services) in a game-hunting ranch in a hot-arid environment (26°4' N, 101°25' W). Ninety additional non-treated does were exposed to bucks for natural mating. Fawning rate did not differ between AI methods (40.0 vs 45.0% for transcervical and laparoscopic AI, respectively). Overall fawning rate (proportion of all does fawning after FTAI and a subsequent period of buck exposure) did not differ between transcervical (89.5%), laparoscopic (80.3%) or natural (88.9%) insemination. Litter size per fawning doe was higher (P<0.05) in naturally-served does (1.65±0.48) than in transcervically-inseminated does (1.40±0.51) or in laparoscopically-inseminated does (1.48±0.50). The main conclusion was that no enhancement of fawning rate or litter size occurred as a result of intrauterine deposition of semen by laparoscopy compared with the transcervical insemination technique.

Biological consequences of winter‐feeding of mule deer in developed landscapes in Northern Utah

AbstractWinter‐feeding of mule deer (Odocoileus hemionus) in developed landscapes is often advocated by stakeholders to compensate for lost or fragmented winter range. However the reported benefits of winter‐feeding mule deer to increase survival and productivity in altered landscapes are mixed. Few studies have examined the long‐term effects of winter‐feeding on mule deer productivity. We studied the effects of a winter‐feeding program conducted in a developed landscape in northern Utah, USA from 2001 to 2006 on the productivity, survival, and mortality of 92 adult female deer (does) that were captured and radiocollared on 4 feed and 4 nonfeed sites. We also evaluated the potential for feeding programs to impact winter‐range habitat quality through increased browse utilization. Fawn production (P = 0.36), and survival (P = 0.12) did not differ for fed and nonfed does. Deer–vehicle collisions were the primary cause of mortality for radiocollared deer in both populations (P = 0.97). Utilization of desired browse species was higher on sites where deer were fed (P ≤ 0.001), although deer numbers were similar at feed and nonfeed sites. When developing big game winter‐feeding policies for developed landscapes, managers must consider the full range of long‐term potential population and habitat impacts to include increased anthropogenic‐related mortality and increased potential for habitat degradation prior to policy implementation. © 2011 The Wildlife Society.

Long‐term effectiveness of US 1 crossing project in reducing florida key deer mortality

AbstractDeer–vehicle collisions (DVCs) are the primary source of mortality for the endangered Florida Key deer (Odocoileus virginianus clavium). Of these collisions, &gt;50% occur on United States Highway 1 (US 1), the primary roadway connecting the islands in the Florida Keys, USA. The DVCs on the 5.6‐km section of US 1 on Big Pine Key are responsible for approximately 26% of annual Key deer mortality, but extensive urban development along this highway segment complicates efforts to reduce DVCs using traditional methods (e.g., fencing, underpasses). In 2002, a continuous 2.6‐km system of 2.4‐m fencing, 2 underpasses, and 4 experimental deer guards was completed. We evaluated the long‐term effectiveness of these highway improvements in reducing DVCs within an urban landscape. Deer used the underpasses all 7 postconstruction years (2003–2009) with dramatic increases in use over the course of the project. Roadway fencing largely eliminated deer intrusion onto the fenced area of US 1. Although well‐maintained fencing effectively restricted deer movement onto the fenced section of US 1 (73–100% decline), other sections of US 1 experienced increases in DVCs. Overall, highway improvements along the US 1 corridor were effective in reducing Key deer mortality over the long‐term. The success of deer guards in preventing deer access into the fenced section of US 1 supported the feasibility of implementing similar wildlife exclusion projects in other urban areas. © 2011 The Wildlife Society.

Survival and harvest‐related mortality of white‐tailed deer in massachusetts

AbstractWe monitored 142 radiocollared adult (≥1.0 yr old) white‐tailed deer (Odocoileus virginianus) in 3 study areas of Massachusetts, USA, to estimate annual survival and mortality due to legal hunting. We then applied these rates to deer harvest information to estimate deer population trends over time, and compared these to trends derived solely from harvest data estimates. Estimated adult female survival rates were similar (0.82–0.86), and uniformly high, across 3 management zones in Massachusetts that differed in landscape composition, human density, and harvest regulations. Legal hunting accounted for 16–29% of all adult female mortality. Estimated adult male survival rates varied from 0.55 to 0.79, and legal hunting accounted for 40–75% of all mortality. Use of composite hunting mortality rates produced realistic estimates for adult deer populations in 2 zones, but not for the third, where estimation was hindered by regulatory restrictions on antlerless deer harvest. In addition, the population estimates we calculated were generally higher than those derived from population reconstruction, likely due to relatively low harvest pressure. Legal harvest may not be the dominant form of deer mortality in developed landscapes; thus, estimates of populations or trends that rely solely on harvest data will likely be underestimates. © 2011 The Wildlife Society.

Demographic response of mule deer to experimental reduction of coyotes and mountain lions in southeastern Idaho

AbstractManipulating predator populations is often posed as a solution to depressed ungulate populations. However, predator–prey dynamics are complex and the effect on prey populations is often an interaction of predator life history, climate, prey density, and habitat quality. The effect of predator removal on ungulate and, more specifically, mule deer (Odocoileus hemionus) populations has not been adequately investigated at a management scale. We tested the efficacy of removing coyotes (Canis latrans) and mountain lions (Puma concolor) for increasing survival and population growth rate of mule deer in southeastern Idaho, USA, during 1997–2003. We assigned 8 game management units (GMUs) to treatments under a 2 × 2 factorial design (treatments of coyote removal and lion removal) with 2 replicates of each treatment or reference area combination. We used methods typically available to wildlife managers to achieve predator removals and a combination of extensive and intensive monitoring in these 8 GMUs to test the hypothesis that predator removal increased vital rates and population growth rate of mule deer. We determined effects of predator removal on survival and causes of mortality in 2 intensive study sites, one with coyote and mountain lion removal and one without. We also considered the effects of other variables on survival including lagomorph abundance and climatic conditions. In these 2 intensive study areas, we monitored with radiotelemetry 250 neonates, 284 6‐month‐old fawns, and 521 adult females. At the extensive scale, we monitored mule deer population trend and December fawn ratios with helicopter surveys. Coyote removal decreased neonate mortality only when deer were apparently needed as alternate prey, thus removal was more effective when lagomorph populations were reduced. The best mortality model of mule deer captured at 6 months of age included summer precipitation, winter precipitation, fawn mass, and mountain lion removal. Over‐winter mortality of adult female mule deer decreased with removal of mountain lions. Precipitation variables were included in most competing mortality models for all age classes of mule deer. Mountain lion removal increased fawn ratios and our models predicted fawn ratios would increase 6% at average removal rates (3.53/1,000 km2) and 27% at maximum removal rates (14.18/1,000 km2). Across our extensive set of 8 GMUs, coyote removal had no effect on December fawn ratios. We also detected no strong effect of coyote or mountain lion removal alone on mule deer population trend; the best population‐growth‐rate model included previous year's mountain lion removal and winter severity, yet explained only 27% of the variance in population growth rate. Winter severity in the current and previous winter was the most important influence on mule deer population growth. The lack of response in fawn ratio or mule deer abundance to coyote reduction at this extensive (landscape) scale suggests that decreased neonate mortality due to coyote removal is partially compensatory. Annual removal of coyotes was not an effective method to increase mule deer populations in Idaho because coyote removal increased radiocollared neonate fawn survival only under particular combinations of prey densities and weather conditions, and the increase did not result in population growth. Coyote‐removal programs targeted in areas where mortality of mule deer fawns is known to be additive and coyote‐removal conditions are successful may influence mule deer population vital rates but likely will not change direction of population trend. Although mountain lion removal increased mule‐deer survival and fawn ratios, we were unable to demonstrate significant changes in population trend with mountain lion removal. In conclusion, benefits of predator removal appear to be marginal and short term in southeastern Idaho and likely will not appreciably change long‐term dynamics of mule deer populations in the intermountain west. © 2011 The Wildlife Society.

Female White-tailed Deer Survival Across Ecoregions in Minnesota and South Dakota

Survival and cause-specific mortality of female white-tailed deer (Odocoileus virginianus) have been well documented in forested and agricultural landscapes, but limited information has been collected in grassland habitats typical of the Northern Great Plains. Our objectives were to document and compare survival and cause-specific mortality of adult female white-tailed deer in four distinct ecoregions. We captured and radiocollared 190 (159 adult, 31 yearling) female white-tailed deer and monitored (including deer from a previous study) a total of 246 (215 adult, 31 yearling) deer from Jan. 2000 to Dec. 2007. We documented 113 mortalities; hunting (including wounding loss) accounted for 69.9% of all mortalities and vehicle collisions accounted for an additional 15.0%. Natural causes (e.g., disease, predation) of mortality were minor compared to human-related causes (e.g., hunting, vehicle collisions). We used known fate modeling in program MARK to estimate survival rates and compare ecoregions and seasons. Model {Sseason (winter = summer)} had the lowest AICc value suggesting that survival differed only between seasons where winter and summer survival was equal and differed with fall season. Annual and seasonal (summer, fall, winter) survival rates using the top model {Sseason (summer = winter)} were 0.76 (95% ci = 0.70–0.80), 0.97 (95% ci = 0.96–0.98), 0.80 (95% ci = 0.76–0.83) and 0.97 (95% ci = 0.96–0.98), respectively. High human-related mortality was likely associated with limited permanent cover, extensive road networks and high hunter density. Deer management in four distinct ecoregions relies on hunter harvest to maintain deer populations within state management goals.

Epizootic Hemorrhagic Disease Outbreak in a Captive Facility Housing White-Tailed Deer (Odocoileus virginianus), Bison (Bison bison), Elk (Cervus elaphus), Cattle (Bos taurus), and Goats (Capra hircus) in Colorado, USA

An ungulate research facility in Fort Collins, Colorado, U.S.A., experienced mortality in white-tailed deer (Odocoileus virginianus) because of epizootic hemorrhagic disease virus (EHDV) infection from 20 August 2007 through 26 September 2007. Epizootic hemorrhagic disease virus (EHDV) was detected by reverse transcriptase polymerase chain reaction and virus isolation from the spleen and lung tissues of two white-tailed deer. Virus neutralization tests were performed on pre- and postoutbreak sera from other species maintained in the same facility, including bison (Bison bison), elk (Cervus elaphus), domestic cattle (Bos taurus), and domestic goats (Capra hircus), as well as postoutbreak sera from the surviving white-tailed deer. Serum samples that represented all species in the facility neutralized EHDV-1 and EHDV-2 either before or after the outbreak. The animals that neutralized EHDV-1 did not neutralize EHDV-2. No clinical signs attributable to EHDV infection were noted in any of the species other than the deer during the outbreak. Although experimental EHDV infections have been reported in bison and elk, natural exposures have not been previously documented in these species in North America. The roles that elk, bison, cattle, and goats might play in the epidemiology of EHDV in a close-contact multispecies situation remain unknown.

Dynamics of a small population of endangered huemul deer (Hippocamelus bisulcus) in Chilean Patagonia

Conservation of huemul (Hippocamelus bisulcus), an endangered South American deer, is hindered by a lack of quantitative information on its population dynamics. We conducted a 3-year study in Chilean Patagonia to assess the dynamics of huemul by monitoring known individuals. We fitted 55 deer of all sex–age classes with either radiocollars, radio ear tags, or conventional ear tags, and identified 33 additional deer through natural marks. Kaplan–Meier estimates revealed that annual survival of adult females was high and stable (0.94 6 0.07 SD), but survival of female fawns was low and variable (0.13 6 0.18). Predation was the predominant cause of mortality for deer of all age classes. Fertility rates were lower (0.72 6 0.20) than in other cervids of similar size. Simulations of the finite rate of increase (l) suggest that the population is currently stable. Sensitivity analysis showed that any decrease in adult female survival would have drastic effects on l. Consequently, management should maintain high adult survival and improve recruitment. Continued monitoring of individuals is required to provide baseline data for comparison with other populations and to inform recovery strategies of small and fragmented populations. DOI: 10.1644/09-MAMM-A-047.1.

Factors affecting road mortality of white- tailed deer in eastern South Dakota

White-tailed deer (Odocoileus virginianus) mortalities (n = 4,433) caused by collisions with automobiles during 2003 were modeled in 35 counties in eastern South Dakota. Seventeen independent variables and 5 independent variable interactions were evaluated to explain deer mortalities. A negative binomial regression model (Ln Y = 1.25 - 0.12 (percentage tree coverage) + 0.0002 (county area) + 5.39 (county hunter success rate) + 0.0023 (vehicle proxy 96-104 km/hr roads), model deviance = 33.43, χ 2 = 27.53, df = 27) was chosen using a combination of a priori model selection and AICc. Management options include use of the model to predict road mortalities and to increase the number of hunting licenses, which could result in fewer DVCs. numbers have increased dramatically in density and distribution during the twentieth century in the United States (McShea and Underwood