The Maternal Effect: Carrying the Consequences of Nutrition Across Generations

Let’s indulge ourselves in a deer-management fantasy for a moment. I’m sure it won’t be your first time! Imagine you are blessed to own and manage your own block of deer country for several years (for many fortunate readers, this is reality, not fantasy). Although the ground you purchase holds plenty of deer, the overgrown forests and grassy meadows might not be providing the nutrition necessary for these deer to achieve their genetic potential. In addition, the 6-foot high browse line resulting from extreme overabundance of deer is a likely indication of why only scrawny looking bucks are typically harvested in the area. However, you know what it takes to have healthy deer herd and grow bigger bucks, and you can see the potential your property holds. Like any responsible steward of the land, you do your homework and go the extra mile to increase the diversity of the habitat and offer more forage and browse. You establish proper food plots with forage high in digestibility and protein. You harvest numerous does each year to reduce deer numbers to a sustainable level, and conservatively harvest bucks to balance the sex ratio and develop an age structure that includes bucks of many ages. During this time, you also foster a small data-collection program framed around the close monitoring of the harvest each year, and in particular the size and age of the bucks being harvested. After a few years of intensive management, hard work, and patience, the property appears to be in better shape; a browse line is no longer evident, deer numbers are in check, bucks and does that are harvested exhibit greater fat levels, and the buck harvest is comprised mainly of mature bucks over 4½ years of age

One in the Hand Worth Two in the Bush? Reproductive Effort of Young Males Is Not Affected by the Presence of Adult Males

Reproduction is a costly endeavor, and most large, long-lived, and iteroparous mammals exhibit conservative life-history tactics wherein an individual may forego or abandon a reproduction event for the sake of survival. Nevertheless, risks and benefits associated with reproduction are not equal across males and females, nor across their life. Whereas expenditure for females is associated with rearing young (e.g., lactation), expenditure for males occurs with securing mating opportunities. Young males may be more successful when dominant males are lacking, but it is less clear whether—and at what cost—young males will expend effort when those opportunities arise. We designed an experiment to quantify reproductive effort (e.g., food intake, somatic loss [body mass and fat]) of male white-tailed deer (Odocoileus virginianus) to better understand the reproductive ecology of male ungulates, with an emphasis on determining how adult males (≥4.5 years old) affect timing and extent of reproductive effort expended by yearling males (1. 5 years old). Food intake, hormone levels, body mass, and somatic loss during rut were similar between yearling males that interacted with adult males and those that did not. Somatic loss by all males was greatest during peak estrus of females, but forage intake relative to metabolic body mass for yearling males was nearly twice that of adult males. Testosterone levels were lower for yearling than adult males early in rut and were related negatively to forage intake. Whereas adult males lost 20% (23.5 kg) of body mass and 31% (5.3 percentage points [ppt]) of body fat during the rut, yearling males lost 12% (9.3 kg) of body mass and 22% (4.7 ppt) of body fat. Reproductive effort by young males was not influenced by the presence of adult males, though young males expended less reproductive effort than adults. Instead, reproductive allocation occurred in a state-dependent manner, where pre-season levels of somatic reserves dictated reproductive effort, regardless of age. Like female ungulates, male deer displayed risk sensitive reproductive allocation wherein current reproductive allocation occurred as a function of resources garnered during the prior season and were expended in a way that should have avoided over-investing and creating a tradeoff between reproduction and survival

Corn Hybrids: Deer Taste the Difference

As daylight begins to illuminate the countryside, a cold wind rustles through the leaves of the weedy rows of corn that you barely had time to get in the ground this past spring. The corn plants are stunted, the few small ears of corn that did grow are not even enticing to passing blackbirds, and that stud buck captured on your trail-camera months earlier is nowhere to be seen. Meanwhile, a couple hundred yards across the fence to the south, you hear the unmistakable sound of deer running through corn. Your heart rate involuntarily increases. As the sun continues to rise on that mid-October morning, the better view of the neighboring cornfield only becomes increasingly disheartening: Numerous whitetails are feeding back and forth across some of the rows already stripped by the combine a couple days prior. The corn plants there are twice as tall as those in your food plot that was intended for the deer, and the ears are comparatively huge with kernels exposed from the peeled-back husks. Just as the sun rises, a doe and her fawn exit the timber to the north and wander down a heavily used trail across your property. The trail leads directly into your corn plot, but the deer do not stop to feed. They continue southward across the road to join the other deer. Then, sure enough, that stud of a buck that you had dreamed about all summer appears in the neighboring cornfield, moves about to assess the receptiveness of each doe, then wanders deeper into the cornfield until he is out of sight

Survival of the Fattest: How Body Fat and Migration Influence Survival in Highly Seasonal Environments

1. Energy stores and migration are important adaptations for animals in seasonal environments, but their roles may vary relative to an animal\u27s endogenous and exogenous environment. In partially migratory populations, migrants and residents experience different seasonal environments; thus, the influence of energy stores on survival may differ relative to migratory tactic, with potential consequences to survival and fitness. 2. Using data from Sierra Nevada bighorn sheep (Ovis canadensis sierrae; hereafter, Sierra bighorn), we tested the hypothesis that body fat (energy stores) buffers animals against their environment, but that buffering capacity differs across environments experienced by high-elevation residents (using a single range year round), traditional migrants (making 1 round-trip movement between high- and low-elevation ranges during winter) and vacillating migrants (making ≥2 round trips between high- and low-elevation ranges during winter). We predicted that: for animals with high levels of body fat, survival would be high regardless of migratory tactic; residents would require larger stores of body fat to survive than migrants; energy stores would be least influential to survival for vacillating migrants. 3. High levels of body fat in autumn (≥14% for females and ≥19% for males) largely buffered animals against harsh environments (survival \u3e0.90) regardless of migratory tactic. At lower levels of body fat, traditional migrants had higher survival than residents. Vacillating migrants exhibited nearly 100% survival with no detectable effect of body fat on survival. 4. Collectively, these results support the hypothesis that body fat buffers animals against harsh environments but that the buffering capacity differed relative to the environment and highly flexible behaviours (i.e. vacillating migration) can allow animals to decouple survival from body fat. 5. Our work reveals that synergies between physiological and behavioural adaptations of animals in highly seasonal environments carry potential fitness consequences for individuals and demographic consequences for populations

Effects of climate and plant phenology on recruitment of moose at the southern extent of their range

Climate plays a fundamental role in limiting the range of a species, is a key factor in the dynamics of large herbivores, and is thought to be involved in declines of moose populations in recent decades. We examined effects of climate and growing-season phenology on recruitment (8–9 months old) of young Shiras moose (Alces alces shirasi) over three decades, from 18 herds, across a large geographic area encompassing much of the southern extent of their range. Recruitment declined in 8 of 18 herds during 1980–2009, whereas others did not exhibit a temporal trend (none showed a positive trend). During those three decades, seasonal temperatures increased, spring–summer precipitation decreased, and spring occurred earlier, became shorter in duration, and green-up occurred faster. Recruitment was influenced negatively by warm temperatures during the year before young were born, but only for herds with declining recruitment. Dry spring–summers of the previous year and rapid rates of spring green-up in the year of birth had similar negative influences across declining and stable herds. Those patterns indicate both direct (yeart) and delayed (yeart−1) effects of weather and plant phenology on recruitment of young, which we hypothesize was mediated through effects on maternal nutritional condition. Suppressed nutrition could have been induced by (1) increased thermoregulatory costs associated with warming temperatures and (2) shortened duration of availability of high-quality forage in spring. Progressive reductions in net energetic gain for species that are sensitive to climate may continue to hamper individual fitness and population dynamics

Re-Evaluating Neonatal-Age Models for Ungulates: Does Model Choice Affect Survival Estimates?

New-hoof growth is regarded as the most reliable metric for predicting age of newborn ungulates, but variation in estimated age among hoof-growth equations that have been developed may affect estimates of survival in staggered-entry models. We used known-age newborns to evaluate variation in age estimates among existing hoof-growth equations and to determine the consequences of that variation on survival estimates. During 2001–2009, we captured and radiocollared 174 newborn (≤24-hrs old) ungulates: 76 white-tailed deer (Odocoileus virginianus) in Minnesota and South Dakota, 61 mule deer (O. hemionus) in California, and 37 pronghorn (Antilocapra americana) in South Dakota. Estimated age of known-age newborns differed among hoof-growth models and varied by \u3e15 days for white-tailed deer, \u3e20 days for mule deer, and \u3e10 days for pronghorn. Accuracy (i.e., the proportion of neonates assigned to the correct age) in aging newborns using published equations ranged from 0.0% to 39.4% in white-tailed deer, 0.0% to 3.3% in mule deer, and was 0.0% for pronghorns. Results of survival modeling indicated that variability in estimates of age-at-capture affected short-term estimates of survival (i.e., 30 days) for white-tailed deer and mule deer, and survival estimates over a longer time frame (i.e., 120 days) for mule deer. Conversely, survival estimates for pronghorn were not affected by estimates of age. Our analyses indicate that modeling survival in daily intervals is too fine a temporal scale when age-at-capture is unknown given the potential inaccuracies among equations used to estimate age of neonates. Instead, weekly survival intervals are more appropriate because most models accurately predicted ages within 1 week of the known age. Variation among results of neonatal-age models on short- and long-term estimates of survival for known-age young emphasizes the importance of selecting an appropriate hoof-growth equation and appropriately defining intervals (i.e., weekly versus daily) for estimating survival

Migrating Mule Deer: Effects of Anthropogenically Altered Landscapes

Background: Migration is an adaptive strategy that enables animals to enhance resource availability and reduce risk of predation at a broad geographic scale. Ungulate migrations generally occur along traditional routes, many of which have been disrupted by anthropogenic disturbances. Spring migration in ungulates is of particular importance for conservation planning, because it is closely coupled with timing of parturition. The degree to which oil and gas development affects migratory patterns, and whether ungulate migration is sufficiently plastic to compensate for such changes, warrants additional study to better understand this critical conservation issue. Methodology/Principal Findings: We studied timing and synchrony of departure from winter range and arrival to summer range of female mule deer (Odocoileus hemionus) in northwestern Colorado, USA, which has one of the largest natural-gas reserves currently under development in North America. We hypothesized that in addition to local weather, plant phenology, and individual life-history characteristics, patterns of spring migration would be modified by disturbances associated with natural-gas extraction. We captured 205 adult female mule deer, equipped them with GPS collars, and observed patterns of spring migration during 2008–2010. Conclusions/Significance: Timing of spring migration was related to winter weather (particularly snow depth) and access to emerging vegetation, which varied among years, but was highly synchronous across study areas within years. Additionally, timing of migration was influenced by the collective effects of anthropogenic disturbance, rate of travel, distance traveled, and body condition of adult females. Rates of travel were more rapid over shorter migration distances in areas of high natural-gas development resulting in the delayed departure, but early arrival for females migrating in areas with high development compared with less-developed areas. Such shifts in behavior could have consequences for timing of arrival on birthing areas, especially where mule deer migrate over longer distances or for greater durations

First Record of the Least Shrew in Wyoming; and \u3ci\u3eClostridium perfingens\u3c/i\u3e Type A Enterotoxemia in a Captive Adult White-tailed Deer

First Record of the Leaast Shrew in Wyoming by Shauna R. Marquardt, Brian C. Bartels, and Cheryl A. Schmidt; and Clostridium perfingens Type A Enterotoxemia in a Captive Adult White-tailed Deer by Joshua A. Delger , Kevin L. Monteith, and Jonathan A. Jenks

Pregnancy Rates, Metabolites and Metabolic Hormones in Bighorn Sheep During and After the Breeding Season

Wildlife managers routinely draw blood and harvest serum when bighorn sheep (Ovis canadensis) and other ungulates are captured for management and research purposes.  Serum samples are routinely submitted to state livestock labs that perform a panel of assays to access exposure to a variety of important pathogens that cause disease, providing managers important insights.  Wildlife managers would also benefit from similar procedures that could provide assessments of reproduction, nutrition, and physiological status.  The objectives of this preliminary study were to evaluate pregnancy rates, energy-related metabolites and hormones among herds of Montana and Wyoming bighorn sheep during and after the breeding season in order to assess the general ‘health’ of herds. Metabolites and metabolic hormones are frequently used in domestic animals to evaluate nutrition, reproduction and energy balance, and potentially may provide the same insights in wildlife for managers. A total of 240 bighorn ewes were sampled from 13 herds between December 2014 and March 2015.  Samples were assayed for progesterone (P4) and pregnancy specific protein B (PSPBs) to assess reproductive cycling and pregnancy. Assays were also performed for non-esterified fatty acid, insulin, triiodothyronine and thyroxine which are metabolites and metabolic hormones that indicate nutritional and energy states of animals. We will be presenting the results of this preliminary study and discussing the relationship between pregnancy rates, energy-related metabolites and hormones and how they might be used to inform wildlife management

Developing Physiological Profiles using Nuclear Magnetic Resonance Spectroscopy to Inform Bighorn Sheep Management

This study employs new techniques using nuclear magnetic resonance (NMR) to assess the relative health, physiological condition, and reproductive function of wild bighorn sheep (Ovis canadensis)  in Montana and Wyoming. Ongoing bighorn studies in Montana and the Greater Yellowstone Ecosystem are focused on herd attributes and the population dynamics which are affected by disease, climate, habitat and physiology. Indices of herd health and physiological status are typically obtained through expensive and time consuming lab assays and field measurements. Recently, NMR spectroscopy has been used to revolutionize the assessment of human metabolic health, and we expect that there is similar potential for studies of wildlife populations. Using NMR spectroscopy to assess metabolites associated with disease, nutrition and stress may eliminate the need for many traditional assays and techniques used today. NMR can be used to evaluate a large suite of metabolites associated with a variety of physiological functions from as little as 500 ?L of serum or plasma. Blood samples from 242 sheep from 13 different herds were collected during the winters of 2013-14 and 2014-15 to develop a comprehensive metabolite panel for bighorn sheep. We have used a recently developed statistical program known as MetaboAnalyst™ to begin to analyze and evaluate differences in NMR metabolic profiles among herds and across the fall-winter season when nutritional and physiological stress is expected to be acute. We will be presenting the results of this preliminary study and discussing the potential for application in wildlife management