Jared F. Duquette

Identifying bobcat Lynx rufus kill sites using a global positioning system

The role of predation in ecological systems has received considerable attention in scientific literature and is one of the most important, yet least understood aspects of carnivore ecology. Knowledge of factors that improve our ability to detect predation events using animal telemetry data could be used to develop strategies to reduce time and resources required to obtain reliable kill estimates. Using Global Positioning System telemetry-collars, we investigated 246 bobcat Lynx rufus location clusters to identify white-tailed deer Odocoileus virginianus kill sites in the Upper Peninsula of Michigan, USA, during May-August, 2009-2011. We documented kills of white-tailed deer at 42 location clusters. We used logistic regression and Akaike Information Criterion for small samples to identify factors (i.e. number of locations in cluster, time from cluster formation to investigation, time of day and land cover) that may influence bobcat behaviour and our ability to detect white-tailed deer kill sites. Clusters with more locations and the search of clusters within 14 days after cluster formation increased odds of detecting bobcat kill sites. The best-performing model was 67% accurate overall and identified 34% of kill sites and 75% of non-kill sites. Applying our best-performing model with the optimal cut-off value would result in a twofold increase in the identification of white-tailed deer kill sites reducing time and effort to find a similar number of kill sites without models by half. Identifying factors that improve our ability to identify bobcat kill sites can reduce field effort and search time.

Effects of maternal nutrition, resource use and multi-predator risk on neonatal white-tailed deer survival.

Growth of ungulate populations is typically most sensitive to survival of neonates, which in turn is influenced by maternal nutritional condition and trade-offs in resource selection and avoidance of predators. We assessed whether resource use, multi-predator risk, maternal nutritional effects, hiding cover, or interactions among these variables best explained variation in daily survival of free-ranging neonatal white-tailed deer (Odocoileus virginianus) during their post-partum period (14 May–31 Aug) in Michigan, USA. We used Cox proportional hazards mixed-effects models to assess survival related to covariates of resource use, composite predation risk of 4 mammalian predators, fawn body mass at birth, winter weather, and vegetation growth phenology. Predation, particularly from coyotes (Canis latrans), was the leading cause of mortality; however, an additive model of non-ideal resource use and maternal nutritional effects explained 71% of the variation in survival. This relationship suggested that dams selected areas where fawns had poor resources, while greater predation in these areas led to additive mortalities beyond those related to resource use alone. Also, maternal nutritional effects suggested that severe winters resulted in dams producing smaller fawns, which decreased their likelihood of survival. Fawn resource use appeared to reflect dam avoidance of lowland forests with poor forage and greater use by wolves (C. lupus), their primary predator. While this strategy led to greater fawn mortality, particularly by coyotes, it likely promoted the life-long reproductive success of dams because many reached late-age (>10 years old) and could have produced multiple generations of fawns. Studies often link resource selection and survival of ungulates, but our results suggested that multiple factors can mediate that relationship, including multi-predator risk. We emphasize the importance of identifying interactions among biological and environmental factors when assessing survival of ungulates.

A Frightening Device for Deterring Deer Use of Cattle Feeders

Abstract The presence of bovine tuberculosis (TB) in cattle can negatively impact a states economy and cattle industry. In Michigan, USA, wild white-tailed deer (Odocoileus virginianus) are a reservoir for reinfecting cattle herds. Although direct TB transmission between deer and cattle is rare, infected deer may contaminate cattle feed. To mitigate this risk, we designed and evaluated a deer-resistant cattle feeder (DRCF) device for deterring deer from feeders. The device delivered negative stimuli to condition deer to avoid cattle feeders. We tested the device by conducting a comparative change experiment at a high-density captive white-tailed deer operation in northeastern lower Michigan using pretreatment and treatment periods and random allocation of DRCF protection to 3 of 6 feeders during the treatment period. We used animal-activated cameras to collect data on deer use of feeders. Deer use was similar at protected and unprotected feeders during the pretreatment period but was lower at protected feeders during the treatment period. Deer-resistant cattle feeders were 100% effective during the first 2 treatment weeks, 94% during the first 5 weeks, but effectiveness then dropped to 61% during the final week. Excluding problems associated with low battery power and infrared sensors, DRCFs were 99% effective at deterring deer. Our results suggest that DRCFs can effectively limit deer use of cattle feed, potentially with minimal impact on feeding behavior of cattle, thus reducing potential transmission of bovine TB through contaminated feed. By employing DRCFs in bovine TB endemic areas, especially at times that deer are food stressed, agencies and producers can practically and economically reduce the potential for bovine TB to be transmitted from deer to cattle.

Badger (Taxidea taxus) Resource Selection and Spatial Ecology in Intensive Agricultural Landscapes

Abstract American badgers (Taxidea taxus) are a prairie obligate species, but badger resource selection and space use is poorly understood, particularly east of the Mississippi River where anthropogenic land uses have replaced most native prairie. We assessed badger multi-scale resource selection and space use in intensive agricultural areas in Illinois and Ohio. We predicted that badgers would select for pasture and prairie, and higher elevations, and riparian areas because these habitats likely favor burrowing and foraging. Conversely, badgers should avoid cropland, roads, and forest at both spatial scales because these habitats may limit burrowing and foraging and potentially increase mortality risk. We also predicted annual male space use would increase with age and be greater than females because of age-related dominance and polygynous mating. We used radiolocations from 18 (11 females, seven males) and five (two females, three males) badgers in Illinois and Ohio, respectively, to estimate space use and multi-spatial scale resource selection. Within study areas, badgers strongly selected for cropland and higher elevations, and a lesser extent upland forest and pasture, but avoided roads and riparian areas. Landcover selection within home ranges varied by study area, but generally, badgers strongly selected for pasture, cropland, prairie, or higher elevation. Median annual 95% fixed kernel areas of Illinois badgers were greater (W8  =  16.00, P  =  0.007) for males than females, and most males appeared to overlap two to three females during the breeding season. We suggest, although our study areas were highly fragmented agricultural landscapes, badgers appeared to select land cover types similar to native prairie, which provided burrowing and foraging opportunities. However, because prairie and pasture were relatively limited, badgers used expansive (x̄  =  20.0 ± 34.4 km2) home ranges to meet life requirements. Therefore, degradation and fragmentation of limiting resources may limit badger population growth in our study areas and should be considered for future management.

American black bear predation of an adult white-tailed deer

Abstract American black bears (Ursus americanus) are opportunistic omnivores and can be proficient predators of neonate ungulates, but predation of adult ungulates is rare. In November 2009 we investigated a probable black bear predation of a radiocollared, adult (7.5 years old) female white-tailed deer (Odocoileus virginianus) in a densely vegetated, lowland conifer forest in the Upper Peninsula of Michigan, USA. The deer carcass was 80% buried with puncture wounds and lacerations on the back and hindquarters. The hide was everted, the intestines and stomach partially eaten, the mammary glands were punctured, and the skeleton remained articulated. All woody vegetation <5.0 cm diameter within 5 m of the carcass was trampled and contained bear and deer hair. We found no evidence of other carnivores. Based on the condition of the carcass, physical evidence at the site, and the similarity of this predation to reported black bear predations, we suggest this deer was attacked and killed by a black bear.

Bald Eagle Predation of a White-Tailed Deer Fawn

Abstract Haliaeetus leucocephalus (Bald Eagle) is an adaptable predatory bird that commonly captures live prey, but regularly scavenges. Large mammalian prey (e.g., Odocoileus virginianus [White-tailed Deer]) have been observed in Bald Eagle diets, but were considered scavenged. To our knowledge, Bald Eagle predation of a live ungulate has only been reported once, and occurred in Menominee County, MI. In June 2009, we captured and radiocollared a female White-tailed Deer fawn (2.7 kg) in the south-central Upper Peninsula of Michigan. The fawn was last radiolocated alive 8 h after release in a short-height (20–30 cm) grassland field along a river approximately 570 m from an eagle nest. Estimated time of mortality of the fawn was 10 h post release. Approximately 27 h post release, 2 legs, >50% fawn hide, and the radiocollar were present in the nest along with 2 eagle nestlings (estimated age 9–10 wks). We believe this was a possible predation event based on the 8-h period between fawn relocations, fawn movement, foraging behavior of the nesting eagles, and presence of the carcass remains and radiocollar in the nest.

Coiban Agouti (Dasyprocta coibae) Density and Temporal Activity on Coiba Island, Veraguas, Panama

Abstract. The Coiban agouti (Dasyprocta coibae) is a meso-sized rodent endemic to Coiba Island, Panama and is ostensibly classified as vulnerable to extinction. Despite this vulnerability, the ecology of the species remains unknown, and baseline estimates of population density and habitat use are needed to develop a scientifically-based conservation status and plan for the species. We recorded 2114 detections of Coiban agoutis using 30 camera traps broadly deployed across the range of habitat types on Coiba Island. We assessed 13 occupancy models using detections of unmarked agoutis, of which the best model estimated 73.3 agoutis/km2, which was positively related to proportion of primary forest. Coiban agouti detection was 86% and was greater on government maintained trails than wildlife trails. Coiban agoutis were most active during daylight (06:00–19:00) hours and during late May to early June. Estimated Coiban agouti density was less than density estimates of related agouti species in tropical forests of Central America with greater predation risk, suggesting habitat may be limited for Coiban agoutis. Our results suggest that a camera trap survey would be effective for future population monitoring of Coiban agoutis, which could be designed to assess the population dynamics and guide the conservation of the species.

Scale Dependence of Female Ungulate Reproductive Success in Relation to Nutritional Condition, Resource Selection and Multi-Predator Avoidance

Female ungulate reproductive success is dependent on the survival of their young, and affected by maternal resource selection, predator avoidance, and nutritional condition. However, potential hierarchical effects of these factors on reproductive success are largely unknown, especially in multi-predator landscapes. We expanded on previous research of neonatal white-tailed deer (Odocoileus virginianus) daily survival within home ranges to assess if resource use, integrated risk of 4 mammalian predators, maternal nutrition, winter severity, hiding cover, or interactions among these variables best explained landscape scale variation in daily or seasonal survival during the post-partum period. We hypothesized that reproductive success would be limited greater by predation risk at coarser spatiotemporal scales, but habitat use at finer scales. An additive model of daily non-ideal resource use and maternal nutrition explained the most (69%) variation in survival; though 65% of this variation was related to maternal nutrition. Strong support of maternal nutrition across spatiotemporal scales did not fully support our hypothesis, but suggested reproductive success was related to dam behaviors directed at increasing nutritional condition. These behaviors were especially important following severe winters, when dams produced smaller fawns with less probability of survival. To increase nutritional condition and decrease wolf (Canis lupus) predation risk, dams appeared to place fawns in isolated deciduous forest patches near roads. However, this resource selection represented non-ideal resources for fawns, which had greater predation risk that led to additive mortalities beyond those related to resources alone. Although the reproductive strategy of dams resulted in greater predation of fawns from alternative predators, it likely improved the life-long reproductive success of dams, as many were late-aged (>10 years old) and could have produced multiple litters of fawns. Our study emphasizes understanding the scale-dependent hierarchy of factors limiting reproductive success is essential to providing reliable knowledge for ungulate management.

Aspiration pneumonia in an American black bear

Abstract Information regarding American black bear (Ursus americanus) mortality caused by disease is limited. Pneumonia is a common respiratory disease that affects many species of wildlife and can result in death. In February 2011, we investigated the death of a yearling male black bear and determined cause of death to be aspiration pneumonia. We found sections of lung were diffusely congested and edematous. A bacterial culture of lung tissue revealed numerous colonies of Klebsiella spp., Alcaligenes faecalis, Aeromonas spp., Corynebacterium spp., and Streptococcus spp. The mixed bacterial colonization of the lungs associated with minimal inflammation is consistent with terminal aspiration of gastrointestinal contents resulting in aspiration pneumonia. Documentation of aspiration pneumonia in black bears can be useful for future researchers interested in the effects of disease on bears.