Louis C. Bender

Jaguar and Puma Predation on Cattle Calves in Northeastern Sonora, Mexico

Abstract Predation by jaguars (Panthera onca) and pumas (Puma concolor) is often a source of conflict with cattle ranching in northeastern Sonora, Mexico. Because jaguars are endangered in Mexico, such conflicts have biological, social, and economic consequences. We documented the extent of predation by jaguars and pumas on cattle in 1999–2004 in northeastern Sonora, where the northernmost breeding population of jaguars exists in North America. Jaguars and pumas killed only calves < 12 mo old, and calves constituted 58% of prey biomass consumed by jaguars and 9% by pumas. Annual cause-specific mortality rates of confirmed jaguar predation (≤ 0.018), confirmed and suspected jaguar predation (≤ 0.018), and all confirmed and suspected large felid predation (≤ 0.018) were low and cattle calf survival was high (0.89–0.98 annually). If calves reported as missing but for which no evidence of mortality could be found were classed as large felid predation, annual cause-specific rates increased to 0.006–0.038. Collectively, confirmed jaguar and puma predation accounted for < 14% (57/408) of total cattle losses, with jaguars responsible for 14% of all calf losses; this could increase to a maximum of 36% (146/408) if missing calves were included in the totals. While jaguar and puma predation may have an impact on some small cattle operations, it is generally minor compared to losses from other causes in northeastern Sonora. Moreover, 91% of all confirmed calf kills were associated with three individual jaguars in our study. Targeting problem cats rather than broad-scale predator control may therefore be a viable alternative to address chronic predation problems. Because most (83%) instances of jaguar predation occurred during the dry season along thick riparian habitats, modified cattle husbandry operations, such as establishment of permanent water sources in uplands and away from dense vegetative cover, could ameliorate many cases of predation by jaguars on cattle.

Survival and Cause-Specific Mortality of Neonatal Mule Deer Fawns, North-Central New Mexico

Abstract Because of significant declines in mule deer (Odocoileus hemionus) populations across New Mexico, USA, we investigated survival of fawns in north-central New Mexico, USA. We captured 19 fawns, 34 fawns, and 47 fawns in 2002, 2003, and 2004, respectively, and used fawn morphological measurements, habitat characteristics, and adult female (hereafter “female”) condition to model preweaning fawn survival. Survival was 0.0, 0.12, 0.52 for 2002, 2003, and 2004, respectively, and was related to birth mass (χ12 = 9.5, P = 0.002), birth date (χ12 = 8.4, P = 0.004), litter size (χ22 = 9.4, P = 0.009), female body fat (χ12 = 40.9, P < 0.001), annual precipitation (χ12 = 35.0, P < 0.001), summer precipitation (χ12 = 37.5, P < 0.001), and winter precipitation (χ12 = 32.0, P < 0.001). Total ingesta-free body fat of females (β = 3.01, SE = 0.75; odds ratio = 20.19, 95% CI = 4.64–87.91) and birth mass of fawns (β = 1.188, SE = 0.428; odds ratio = 3.38, 95% CI = 1.42–7.59) were the best predictors of survival of individual fawns, although few of the logistic models differed in model selection criteria. Fawn survival in north-central New Mexico was driven by an interaction of total and seasonal precipitation and its effect on plant production, consequential effects on female nutrition, and ultimately, fawn birth attributes. Habitat conditions were so poor throughout north-central New Mexico during 2002 and 2003 (and likely during other drought yr) that, based upon birth attributes, few fawns could have survived regardless of proximate causes of mortality. In 2004, precipitation enhanced security cover, maternal body condition, birth attributes and, thus, survival of fawns. However, more habitat enhancements are needed to improve the nutritional quality of mule deer habitats in north-central New Mexico and further enhance maternal and fawn condition to recover mule deer populations in this region.

Den-site characteristics of black bears in Rocky Mountain National Park, Colorado

Abstract We compared historic (1985–1992) and contemporary (2003–2006) black bear (Ursus americanus) den locations in Rocky Mountain National Park (RMNP), Colorado, USA, for habitat and physiographic attributes of den sites and used maximum entropy modeling to determine which factors were most influential in predicting den-site locations. We observed variability in the relationship between den locations and distance to trails and elevation over time. Locations of historic den sites were most associated with slope, elevation, and covertype, whereas contemporary sites were associated with slope, distance to roads, aspect, and canopy height. Although relationships to covariates differed between historic and contemporary periods, preferred den-site characteristics consistently included steep slopes and factors associated with greater snow depth. Distribution of den locations shifted toward areas closer to human developments, indicating little negative influence of this factor on den-site selection by black bears in RMNP.

Production and Survival of Elk (Cervus elaphus) Calves in Michigan

Abstract We determined production and survival of elk (Cervus elaphus nelsoni) calves in Michigan using a variety of methods to index herd productivity. Calf production in Michigan was comparable with the highest rates ever recorded for North American elk. Calf survival averaged 0.90 (sd = 0.05), 0.97 (sd = 0.04) and 0.87 (sd = 0.05) for summer, winter and annually, 1987–1991. Calf survival rates in Michigan were higher than in other North American elk populations. Continued high calf production, in combination with high calf survival, indicates that elk condition is excellent in Michigan, as habitat quality allows cow elk to breed and successfully raise a calf, essentially every year, despite the high energetic demands associated with late gestation and lactation.

Evidence of three new members of malignant catarrhal fever virus group in muskox (Ovibos moschatus), Nubian ibex (Capra nubiana), and gemsbok (Oryx gazella).

Six members of the malignant catarrhal fever (MCF) virus group of ruminant rhadinoviruses have been identified to date. Four of these viruses are clearly associated with clinical disease: alcelaphine herpesvirus 1 (AlHV-1) carried by wildebeest (Connochaetes spp.); ovine herpesvirus 2 (OvHV-2), ubiquitous in domestic sheep; caprine herpesvirus 2 (CpHV-2), endemic in domestic goats; and the virus of unknown origin found causing classic MCF in white-tailed deer (Odocoileus virginianus; MCFV-WTD). Using serology and polymerase chain reaction with degenerate primers targeting a portion of the herpesviral DNA polymerase gene, evidence of three previously unrecognized rhadinoviruses in the MCF virus group was found in muskox (Ovibos moschatus), Nubian ibex (Capra nubiana), and gemsbok (South African oryx, Oryx gazella), respectively. Based on sequence alignment, the viral sequence in the muskox is most closely related to MCFV-WTD (81.5% sequence identity) and that in the Nubian ibex is closest to CpHV-2 (89.3% identity). The viral sequence in the gemsbok is most closely related to AlHV-1 (85.1% identity). No evidence of disease association with these viruses has been found.

Condition, Survival, and Cause-Specific Mortality of Adult Female Mule Deer in North-Central New Mexico

Abstract From December 2001 to December 2004 we monitored 30–44 adult female mule deer (Odocoileus hemionus) annually to assess the factors affecting survival and cause-specific mortality. We found adult female survival of 0.63 (SE = 0.08), 0.90 (SE = 0.05), and 0.91 (SE = 0.04), 2002–2004, respectively. Starvation was the most common cause of mortality, accounting for 11/23 mortalities. Mean ingesta-free body fat (IFBF) levels of adult females in December were low (6–9%), despite few (0–13%) lactating adult females, indicative of extremely nutritionally deficient summer–autumn ranges throughout the study site. A priori levels of IFBF and rump body condition scores (rBCS) were higher in deer that survived the following year regardless of cause of mortality. Logistical analysis indicated that models containing individual body fat, rBCS, mean population body fat, winter precipitation, precipitation during mid- to late gestation, and total annual precipitation were related (χ2 ≥ 9.1; P ≤ 0.003) to deer survival, with individual IFBF (β = −0.47 [SE = 0.21]; odds ratio = 0.63 [0.42–0.94]) and population mean IFBF (β = −1.94 [SE = 0.68]; odds ratio = 0.14 [0.04–0.54]) the best predictors; with either variable, probability of dying decreased as fat levels increased. Fawn production was low (2–29 fawns/100 ad F) and, combined with adult survival, resulted in estimated population rates of increase of −35%, −5%, and +6% for 2002–2004, respectively. Deer survival and population performance were limited in north-central New Mexico, USA, due to poor condition of deer, likely a result of limited food resulting from both drought and long-term changes in plant communities. Precipitation during mid- to late gestation was also important for adult female survival in north-central New Mexico.

Relations between nutritional condition and survival of North American elk Cervus elaphus

Abstract We related annual and seasonal survival of four populations of elk Cervus elaphus in the Pacific Northwest, USA, to measures and indices of individual nutritional condition. Among populations, for all mortality (human and non-human causes) sources inclusive, annual survival of adult females was correlated with a rump body condition score (rs = 0.627, P = 0.071), and survival over spring-summer-autumn (SSA) was correlated with mean ingesta-free body fat (IFBF; rs = 0.567, P = 0.088) and rump body condition score (rBCS; rs = 0.615, P = 0.050). For non-human mortality sources only, survival through SSA was correlated with IFBF (rs = 0.567, P = 0.088) and rBCS (rs = 0.615, P = 0.050), and survival over winter was correlated with withers body condition score (rs = 0.677, P = 0.045). For human-caused mortality sources only, survival over SSA was correlated with rBCS (rs = 0.696, P = 0.036) and IFBF (rs = 0.696, P = 0.036). For individuals, logistic analysis found that individual likelihood of dying from all mortality sources inclusive was best predicted (χ2 = 8.3, P = 0.004, β = −1.24) by longissimus dorsi (loin) muscle thickness, a measure of protein catabolism. For only non-human mortality sources, a model (χ2=16.1, P = 0.0003) containing both loin muscle thickness (χ2 = 5.7, P = 0.017, β = −1.02) and percent ingesta-free body fat (χ2 = 4.9, P = 0.027, β = −0.35) best predicted individual susceptibility to mortality. Odds ratios indicated that odds of dying increased approximately 3X for each centimeter of loin muscle catabolized and 1.4X for each percent less body fat. No condition indices at the individual level were related to survival from human-caused mortality sources. Our study populations were characterized by low-marginal condition (i.e. mean ingesta-free body fat levels of 5.9-12.3% for lactating cows in late autumn); this likely increased the prominence of measures of muscle catabolism relative to fat accretion in influencing individual elk survival. Elk populations throughout the Pacific Northwest likely show similar condition levels, and consequently individuals are predisposed to mortality to a much greater degree than under optimal foraging conditions. Management strategies which assume that nutritional condition affects vulnerability only at or near condition levels associated with ecological carrying capacity (i.e. near starvation mortality) may overestimate the impact of proximate mortality factors on adult female elk.

SURVIVAL, CAUSE-SPECIFIC MORTALITY, AND HARVESTING OF MALE BLACK-TAILED DEER IN WASHINGTON

Abstract We determined survival rates, causes of mortality, and documented impacts of harvest on ≥1.5-year-old male (hereafter, male) Columbian black-tailed deer (Odocoileus hemionus columbianus) in 2 Washington, USA, game management units (GMUs; Skookumchuck and Snoqualmie) characterized by different hunting-season structures. We monitored 66 males (n = 28 and 38 annually) in Skookumchuck and 58 males (n = 26 and 32 annually) in Snoqualmie, September 1999–September 2001. Annual survival rates were 0.498 (SE = 0.066) in Skookumchuck and 0.519 (SE = 0.067) in Snoqualmie. Survival rates derived from population age structure did not differ from rates derived from radiotelemetry. Harvest was the primary mortality factor for each population, accounting for 67% (SE = 7; Skookumchuck) to 44% (SE = 9; Snoqualmie) of total annual mortality. Annual harvest-specific mortality rates were 0.317 (SE = 0.032) in Skookumchuck and 0.211 (SE = 0.021) in Snoqualmie, likely due to longer hunting seasons and greater hunter effort in Skookumchuck. Following the elimination of a late buck season centered on the rut in Snoqualmie, male harvest declined 56% and annual survival increased 60%, indicating that male harvest was largely additive to other mortality. Our results indicated that harvest was the primary influence on male black-tailed deer populations in Washington, was additive, and that the effect of harvest varied with hunting-season structure and hunter effort. Managers should not assume that harvesting removes a constant proportion of the male population annually, and management models that assume compensatory mortality in adult harvest may result in overharvest of male populations.

DISTRIBUTION, OCCUPANCY, AND HABITAT CORRELATES OF AMERICAN MARTENS (MARTES AMERICANA) IN ROCKY MOUNTAIN NATIONAL PARK, COLORADO

Abstract A clear understanding of habitat associations of martens (Martes americana) is necessary to effectively manage and monitor populations. However, this information was lacking for martens in most of their southern range, particularly during the summer season. We studied the distribution and habitat correlates of martens from 2004 to 2006 in Rocky Mountain National Park (RMNP) across 3 spatial scales: site-specific, home-range, and landscape. We used remote-sensored cameras from early August through late October to inventory occurrence of martens and modeled occurrence as a function of habitat and landscape variables using binary response (BR) and binomial count (BC) logistic regression, and occupancy modeling (OM). We also assessed which was the most appropriate modeling technique for martens in RMNP. Of the 3 modeling techniques, OM appeared to be most appropriate given the explanatory power of derived models and its incorporation of detection probabilities, although the results from BR and BC provided corroborating evidence of important habitat correlates. Location of sites in the western portion of the park, riparian mixed-conifer stands, and mixed-conifer with aspen patches were most frequently positively correlated with occurrence of martens, whereas more xeric and open sites were avoided. Additionally, OM yielded unbiased occupancy values ranging from 91% to 100% and 20% to 30% for the western and eastern portions of RMNP, respectively.

Uses of Herd Composition and Age Ratios in Ungulate Management

Abstract Wildlife managers commonly collect sex and age ratios to manage ungulate populations. This information typically is used to assess trends in population goals (e.g., bull elk [Cervus elaphus] escapement). Many managers may be unaware or underestimate the amount of information that can be derived from these commonly collected ratios. Herein, I review types of information applicable to population management that can be derived from composition ratios. This information includes mortality or survival rates, maximum sustainable mortality levels, and adult sex ratios. Further, I demonstrate the interaction of ratios with each other. Herd composition and age ratios can provide significant relevant data for population management, but care must be used in their interpretation.