USDA National Wildlife Research Center - Staff Publications

Domestic Calf Mortality And Producer Detection Rates In The Mexican Wolf Recovery Area: Implications For Livestock Management And Carnivore Compensation Schemes.

Stewart W. Breck et al. — Fri, 06 Apr 2012 15:03:01 PDT

Conserving large carnivores throughout the world will often require that they share the landscape with livestock. Minimizing depredations and increasing tolerance by livestock producers will be critical for conservation efforts. To investigate factors influencing calf mortality and producer detection rates (i.e., number of livestock killed by predators, found by producers, and correctly classified as to cause of death), we monitored radio-tagged domestic calves at two sites in the Mexican wolf recovery area (East Eagle [EE] and Adobe Ranch [AR]). Study areas differed in grazing practices, density of predators (mountain lions, black bears, coyotes, and Mexican wolves), and amount of effort spent monitoring cattle. We radiotagged 618 calves over 3.5 years, and 312 calves over 2 years on the EE and AR, respectively. The overall proportion of radioed calves that died was higher on the EE (6.5%) than on the AR (1.9%). Predators (especially mountain lions) accounted for 85% of mortality on the EE and 0% on the AR. Calves selected by predators were on average 25 days younger than the surviving cohort. Our results indicate that year-round calving, especially in areas with high predator densities, are subject to higher losses primarily because calves are exposed to mortality agents for longer periods of time rather than having higher natural rates of mortality. We found a significant difference in producer detection rates between study sites, likely due to differences in the intensity of monitoring cattle between sites. On the EE, the producer detected 77.5% of mortalities and on the AR, the producer detected 33% of mortalities. Our results support changing husbandry practices to limit calving to a seasonal endeavor and that performance payment may be a better compensation strategy than ex post compensation schemes.

Natal Colony Site Fidelity Of Herring Gulls At Sandusky Bay, Ohio.

Bruce N. Buckingham et al. — Fri, 06 Apr 2012 15:02:53 PDT

We studied three Herring Gull (Larus argentatus) colonies in the Sandusky Bay area, Sandusky, OH, between 1981 and 2006. During this period, we banded 24,000 nestlings and received reports of 347 recovered bands. Forty-nine of these band recoveries were as adults recovered during the nesting season as far as 890 km from their natal colony. Gulls were also captured at five other colonies located in the Great Lakes. Gulls recovered outside the original 10-min block of banding accounted for 47 percent of the returns. We hypothesize that half of the recoveries of adult Herring Gulls during the nesting season occurred outside their natal colony, because prime nesting locations within a colony became scarce and suboptimal nesting locations were the only option for nesting.

Absence Of Mycobacterium Bovis In Feral Swine (Sus Scrofa) From The Southern Texas Border Region.

Tyler A. Campbell et al. — Fri, 06 Apr 2012 15:02:45 PDT

Free-ranging wildlife, such as feral swine (Sus scrofa), harbor a variety of diseases that are transmissible to livestock and could negatively impact agricultural production. Information is needed regarding the exposure and infection rates of Mycobacterium bovis and many other diseases and parasites in feral swine occurring in the Texas border region. Our main objective was to determine exposure rates and possible infection rates of M. bovis in feral swine by opportunistically sampling animals from the Texas border region. From June to September 2010, we obtained samples from 396 feral swine and tested 98 samples for M. bovis by histopathology and mycobacteriologic culture. We found no evidence of M. bovis infection. We believe that it is important to periodically and strategically sample feral swine for M. bovis in high-risk areas of the United States because they are capable of becoming reservoirs of the disease.

Efficacy Of The Boar-Operated-System To Deliver Baits To Feral Swine.

Tyler A. Campbell et al. — Fri, 06 Apr 2012 15:02:37 PDT

Feral swine (Sus scrofa) pose a significant disease threat to livestock and humans. Emerging technologies to reduce feral swine disease transmission risks include fertility control, vaccination, and toxicants. However, for these technologies to be appropriate for field application, a feral swine-specific oral delivery system is needed. We used two field trials to generate information related to appropriate field application of the Boar-Operated-System (BOSTM), an oral delivery system designed to provide bait access only to feral swine. Our objectives were to determine whether pre-baiting BOSTM units increased bait removal and to evaluate the proportion of feral swine and non-target animals that ingest baits designed to deliver pharmaceuticals through the BOSTM. During both trials we used baits housed within 10 BOSTM units.Wemonitored wildlife visitation, bait removal, and ingestion using motion sensing digital photography and baits containing the bait marker tetracycline hydrochloride (TH). During trial 1 we found three of five pre-baited BOSTM units were used by feral swine only. Additionally, we found the five BOSTM units that were not pre-baited were not used by feral swine or non-target wildlife. During trial 2 we determined bait removal from the BOSTM to be reduced by only 10% for feral swine when activated, whereas bait removal from the BOSTM by all other wildlife was reduced by 100% when activated. We captured 81 feral swine and 23 raccoons and found 90% and 13% to have TH-marked teeth, respectively. With minor modifications, the BOSTM should be considered a valuable tool to be used in feral swine disease management in conjunction with existing technologies.

Diseases and Parasites

Kurt C. Vercauteren et al. — Fri, 06 Apr 2012 15:02:30 PDT

Nilgai Antelope In Northern Mexico As A Possible Carrier For Cattle Fever Ticks And Babesia Bovis And Babesia Bigemina.

E M. Cardenas-Canales et al. — Fri, 06 Apr 2012 15:02:22 PDT

Of 20 blood samples from nilgais from Me´ xico, five were polymerase chain reaction-positive for Babesia bigemina and one for Babesia bovis. Positive samples had the expected 170 (B. bigemina) and 291 (B. bovis) base pairs and were identical to Gen-Bank B. bigemina accession S45366 and B. bovis M38218.

Rock Pigeon Use Of Livestock Facilities In Northern Colorado: Implications For Improving Farm Bio-Security.

James C. Carlson et al. — Fri, 06 Apr 2012 15:02:14 PDT

Rock pigeons (Columba livia) have been implicated in the spread of pathogens within commercial livestock facilities. Currently, there is no data characterizing pigeon habitat use and movement patterns within and among commercial livestock facilities. To better understand the capacity for pigeons to spread pathogens, we used radio-telemetry techniques to estimate the home-range, travel distance, activity, and habitat use of pigeons roosting on and off dairies and feedlots in western Weld County, Colorado. Our observations suggest that pigeons roosting on (resident) and off (nonresident) livestock facilities use habitat differently. Nonresident pigeons used larger home-range areas than did resident pigeons. Nonresident pigeons traveled farther and frequented more livestock facilities than did resident pigeons. Both resident and nonresident pigeons disproportionally selected livestock facilities over other available foraging sites. We detected no difference in pigeon activities (i.e. loafi ng, feeding, drinking, fl ying) between resident and nonresident pigeons. Data suggest that nonresident pigeons may vector livestock pathogens among livestock facilities and resident pigeons may aid in the amplifi cation and maintenance of pathogens within livestock facilities. Thus, targeted management of pigeons may help mitigate the introduction and maintenance of pathogens that cause disease and economic loss within livestock facilities.

Efficacy Of European Starling Control To Reduce Salmonella Enterica Contamination In A Concentrated Animal Feeding Operation In The Texas Panhandle

James C. Carlson et al. — Fri, 06 Apr 2012 15:02:06 PDT

Background: European starlings (Sturnus vulgaris) are an invasive bird species known to cause damage to plant and animal agriculture. New evidence suggests starlings may also contribute to the maintenance and spread of diseases within livestock facilities. Identifying and mitigating the risk pathways that contribute to disease in livestock is necessary to reduce production losses and contamination of human food products. To better understand the impact starlings have on disease transmission to cattle we assessed the efficacy of starling control as a tool to reduce Salmonella enterica within a concentrated animal feeding operation. We matched a large facility, slated for operational control using DRC-1339 (3-chloro-4-methylaniline hydrochloride, also 3-chloro ptoluidine hydrochloride, 3-chloro-4-methylaniline), with a comparable reference facility that was not controlling birds. In both facilities, we sampled cattle feed, cattle water and cattle feces for S. enterica before and after starling control operations. Results: Within the starling-controlled CAFO, detections of S. enterica contamination disappeared from feed bunks and substantially declined within water troughs following starling control operations. Within the reference facility, detections of S. enterica contamination increased substantially within feed bunks and water troughs. Starling control was not observed to reduce prevalence of S. enterica in the cattle herd. Following starling control operations, herd prevalence of S. enterica increased on the reference facility but herd prevalence of S. enterica on the starling-controlled CAFO stayed at pretreatment levels. Conclusions: Within the starling-controlled facility detections of S. enterica disappeared from feed bunks and substantially declined within water troughs following control operations. Since cattle feed and water are obvious routes for the ingestion of S. enterica, starling control shows promise as a tool to help livestock producers manage disease. Yet, we do not believe starling control should be used as a stand alone tool to reduce S. enterica infections. Rather starling control could be used as part of a comprehensive disease management plan for concentrated animal feeding operations.

"References" for Carnivore Conservation

John L. Gittleman et al. — Fri, 06 Apr 2012 15:01:58 PDT

119-page bibliography of works cited in in CARNIVORE CONSERVATION, edited by John L. Gittleman, Stephan M. Funk, David Macdonald, and Robert K. Wayne, Cambridge University Press, 2001.

Includes approximately 2,000 items.

Effects of Intraguild Predation: Evaluating Resource Competiotn Between Two Canid Species With Apparent Niche Separation

Adam J. Kozlowski et al. — Fri, 24 Feb 2012 14:52:37 PST

Many studies determine which habitat components are important to animals and the extent their use may overlap with competitive species. However, such studies are often undertaken after populations are in decline or under interspecific stress. Since habitat selection is not independent of interspecific stress, quantifying an animal's current landscape use could be misleading if the species distribution is suboptimal. We present an alternative approach by modeling the predicted distributions of two sympatric species on the landscape using dietary preferences and prey distribution. We compared the observed habitat use of kit foxes (Vulpes macrotis) and coyotes (Canis latrans) against their predicted distribution. Data included locations of kit foxes and coyotes, carnivore scat transects, and seasonal prey surveys. Although habitats demonstrated heterogeneity with respect to prey resouces, only coyotes showed habitat use designed to maximize access to prey. In contrast, kit foxes used habitats which did not align closely with prey resources. Instead, habitat use by kit foxes represented spatial and behavioral strategies designed to minimize spatial overlap with coyotes while maximizing access to resources. Data on the distribution of prey, their dietary importance, and the species-specific disparities between predicted and observed habitat distributions supports a mechanism by which kit fox distribution is derived from intense competitive interactions with coyotes.

Wild Dogma: An Examination Of Recent "Evidence" For Dingo Regulation Of Invasive Mesopredator Release In Australia.

Benjamin L. Allen et al. — Fri, 24 Feb 2012 12:33:37 PST

There is growing interest in the role that apex predators play in shaping terrestrial ecosystems and maintaining trophic cascades. In line with the mesopredator release hypothesis, Australian dingoes (Canis lupus dingo and hybrids) are assumed by many to regulate the abundance of invasive mesopredators, such as red foxes Vulpes vulpes and feral cats Felis catus, thereby providing indirect benefits to various threatened vertebrates. Several recent papers have claimed to provide evidence for the biodiversity benefits of dingoes in this way. Nevertheless, in this paper we highlight several critical weaknesses in the methodological approaches used in many of these reports, including lack of consideration for seasonal and habitat differences in activity, the complication of simple track-based indices by incorporating difficult-to-meet assumptions, and a reduction in sensitivity for assessing populations by using binary measures rather than potentially continuous measures. Of the 20 studies reviewed, 15 of them (75%) contained serious methodological flaws, which may partly explain the inconclusive nature of the literature investigating interactions between invasive Australian predators. We therefore assert that most of the “growing body of evidence” for mesopredator release is merely an inconclusive growing body of literature only. We encourage those interested in studying the ecological roles of dingoes relative to invasive mesopredators and native prey species to account for the factors we identify, and caution the value of studies that have not done so.

Wild Dogma II: The Role And Implications Of Wild Dogma For Wild Dog Management In Australia.

Benjamin L. Allen et al. — Fri, 24 Feb 2012 12:33:29 PST

The studies of Allen (2011) and Allen et al. (2011) recently examined the methodology underpinning claims that dingoes provide net benefits to biodiversity by suppressing foxes and cats. They found most studies to have design flaws and/or observational methods that preclude valid interpretations from the data, describing most of the current literature as ‘wild dogma’. In this short supplement, we briefly highlight the roles and implications of wild dogma for wild dog management in Australia. We discuss nomenclature, and the influence that unreliable science can have on policy and practice changes related to apex predator management

Partitioning Of Anthropogenic Watering Sites By Desert Carnivores.

Todd C. Atwood et al. — Fri, 24 Feb 2012 12:33:22 PST

We investigated the role of water features as focal attractors for gray foxes (Urocyon cinereoargenteus), coyotes (Canis latrans), and bobcats (Felis rufus) in west Texas to determine if they were foci for interspecific interaction. Mixed effects models indicated that species partitioned use of water features spatially and temporally. Linear models indicated factors influencing relative activity at water features varied by species. For coyotes and bobcats, the water availability model, containing days since last rainfall and nearest-neighbor distance to water was best supported by the data, with relative activity increasing with time between rainfall and distance between waters. For gray foxes, the best approximating model indicated that relative activity was inversely correlated to coyote and bobcat activity indices, and positively correlated to topographical complexity. Encounters between carnivore species were low, with most occurring between coyotes and gray foxes, followed by coyotes and bobcats, and bobcats and gray foxes. These findings suggest a behavioral-environmental mechanism that may function to modulate resource partitioning by carnivores in the arid West.

Modeling Connectivity of Black Bears in a Desert Sky Island Archipelago

Todd C. Atwood et al. — Fri, 24 Feb 2012 12:33:14 PST

Landscape features such as rivers, mountains, desert basins, roads, and impermeable man-made structures may influence dispersal and gene flow among populations, thereby creating spatial structure across the landscape. In the US–Mexico borderland, urbanization and construction of the border fence have the potential to increase genetic subdivision and vulnerability to isolation in large mammal populations by bisecting movement corridors that have enabled dispersal between adjacent Sky Island mountain ranges. We examined genetic variation in black bears (Ursus americanus) from three regions in central and southern Arizona, US, to assess genetic and landscape connectivity in the US–Mexico border Sky Islands. We found that the three regions grouped into two subpopulations: the east-central subpopulation comprised of individuals sampled in the central highland and high desert regions, and the border subpopulation comprised of individuals sampled in the southern Sky Islands. Occupancy for the border subpopulation of black bears was influenced by cover type and distance to water, and occupancy-based corridor models identified 14 potential corridors connecting border Sky Island habitat cores with the east-central subpopulation. Biological quality of corridors, defined as length:width ratio and proportions of suitable habitat within corridors, declined with Sky Island dispersion. Our results show that black bears in the border subpopulation are moderately isolated from the east-central subpopulation, the main population segment of black bears in Arizona, and that connectivity for border bears may be vulnerable to anthropogenic activities, such as those associated with urbanization and trans-border security.

Hair of the Dog: Obtaining Samples From Coyotes and Wolves Noninvasively

David E. Ausband et al. — Fri, 24 Feb 2012 12:33:06 PST

Canids can be difficult to detect and their populations difficult to monitor. We tested whether hair samples could be collected from coyotes (Canis latrans) in Texas, USA and gray wolves (C. lupus) in Montana, USA using lure to elicit rubbing behavior at both man-made and natural collection devices. We usedmitochondrial and nuclearDNA to determine whether collected hair samples were from coyote, wolf, or nontarget species. Both coyotes and wolves rubbed on man-made barbed surfaces but coyotes in Texas seldom rubbed on hanging barbed surfaces. Wolves in Montana showed a tendency to rub at stations where natural material collection devices (sticks and debris) were present. Time to detection was relatively short (5 nights and 4 nights for coyotes and wolves, respectively) with nontarget and unknown species comprising approximately 26% of the detections in both locations. Eliciting rubbing behavior from coyotes and wolves using lures has advantages over opportunistic genetic sampling methods (e.g., scat transects) because it elicits a behavior that deposits a hair sample at a fixed sampling location, thereby increasing the efficiency of sampling for these canids. Hair samples from rub stations could be used to provide estimates of abundance, measures of genetic diversity and health, and detection–nondetection data useful for cost-effective population monitoring.

Acetaminophen and Zinc Phosphide For Lethal Management of Invasive Lizards Ctenosaura similis

Michael L. Avery et al. — Fri, 24 Feb 2012 12:32:59 PST

Reducing populations of invasive lizards through trapping and shooting is feasible in many cases but effective integrated management relies on a variety of tools, including toxicants. In Florida, using wild-caught non-native black spiny-tailed iguanas Ctenosaura similis, we screened acetaminophen and zinc phosphide to determine their suitability for effective population management of this prolific invasive species. Of the animals that received acetaminophen, none died except at the highest test dose, 240 mg per lizard, which is not practical for field use. Zinc phosphide produced 100% mortality at dose levels as little as 25 mg per lizard, equivalent to about 0.5% in bait which is lower than currently used in commercial baits for commensal rodent control. We conclude that zinc phosphide has potential as a useful tool for reducing populations of invasive lizards such as the black spiny-tailed iguana provided target-selective delivery methods are developed

Vulture Flight Behavior and Implications for Aircraft Safety

Michael L. Avery et al. — Fri, 24 Feb 2012 12:32:51 PST

Growing vulture populations represent increasing hazards to civil and military aircraft. To assess vulture flight behavior and activity patterns at the Marine Corps Air Station in Beaufort, South Carolina, we equipped 11 black vultures (Coragyps atratus) and 11 turkey vultures (Cathartes aura) with solarpowered Global Positioning System (GPS) satellite transmitters during a 2-year study (1 Oct 2006–30 Sep 2008). Turkey vultures had larger seasonal home ranges than did black vultures, and 2 turkey vultures made round-trips to Florida. Black vultures consistently spent less time in flight (8.4%) than did turkey vultures (18.9%), and black vultures flew at higher altitudes than did turkey vultures in all seasons except summer when altitudinal distributions (above ground level) did not differ. Although we recorded maximum altitudes of 1,578 mfor black vultures and 1,378 for turkey vultures, most flights were low altitude. A matrix of vulture flight altitude versus time of day revealed that >60% of vulture flight activity occurred from 4 hr to 9 hr after sunrise at altitudes below 200 m. Continuation of aggressive harassment coupled with flexible training schedules to avoid times and altitudes of high vulture activity will decrease hazards to aircraft posed by these birds.

The Carrot Or The Stick? Evaluation Of Education And Enforcement As Management Tools For Human-Wildlife Conflicts.

Sharon Baruch-Mordo et al. — Fri, 24 Feb 2012 12:32:44 PST

Evidence-based decision-making is critical for implementing conservation actions, especially for human-wildlife conflicts, which have been increasing worldwide. Conservation practitioners recognize that long-term solutions should include altering human behaviors, and public education and enforcement of wildlife-related laws are two management actions frequently implemented, but with little empirical evidence evaluating their success. We used a system where human-black bear conflicts were common, to experimentally test the efficacy of education and enforcement in altering human behavior to better secure attractants (garbage) from bears. We conducted 3 experiments in Aspen CO, USA to evaluate: 1) on-site education in communal dwellings and construction sites, 2) Bear Aware educational campaign in residential neighborhoods, and 3) elevated law enforcement at two levels in the core business area of Aspen. We measured human behaviors as the response including: violation of local wildlife ordinances, garbage availability to bears, and change in use of bear-resistance refuse containers. As implemented, we found little support for education, or enforcement in the form of daily patrolling in changing human behavior, but found more support for proactive enforcement, i.e., dispensing warning notices. More broadly we demonstrated the value of gathering evidence before and after implementing conservation actions, and the dangers of measuring responses in the absence of ecological knowledge. We recommend development of more effective educational methods, application of proactive enforcement, and continued evaluation of tools by directly measuring change in human behavior. We provide empirical evidence adding to the conservation managers’ toolbox, informing policy makers, and promoting solutions to human-wildlife conflicts.

White-Tailed Deer Incidents With U.S. Civil Aircraft

Kirsten M. Biondi et al. — Fri, 24 Feb 2012 12:32:36 PST

Aircraft incidents with ungulates cause substantial economic losses and pose risks to human safety. We analyzed 879 white-tailed deer (Odocoileus virginianus) incidents with United States civil aircraft from 1990 to 2009 reported in the Federal Aviation Administration National Wildlife Strike Database. During that time, deer incidents followed a quadratic response curve, peaking in 1994 and declining thereafter. There appeared to be some seasonal patterning in incident frequency, with deer incidents increasing overall from January to November, and peaking in October and November (30.7%). Most incidents (64.8%) occurred at night, but incident rates were greatest (P 0.001) at dusk. Landing-roll represented 60.7% of incidents and more incidents occurred during landing than take-off (P 0.001). Almost 70% of deer incidents had an effect on flight. About 6% of pilots attempted to avoid deer, and were less likely to sustain damage. Aircraft were 25 times more likely to be destroyed when multiple deer were struck versus a single individual. Deer incidents represented 0.9% of all wildlife incidents, yet 5.4% of total estimated costs. Reported costs for deer incident damages during this period exceeded US$36 million, with US$75 million in total estimated damages. Deer incidents resulted in 1 of 24 human deaths and 26 of 217 injuries reported for all wildlife incidents with aircraft during the reporting period. Managers should implement exclusion techniques (e.g., fences, cattle guards, or electrified mats) to maximize reductions in deer use of airfields. Where exclusion is not practical, managers should consider lethal control, habitat modifications, increased monitoring and hazing, and improved technology to aircraft and runway lighting to reduce incidents at airports.

Active Use of Coyotes (Canis latrans) To Detect Bovine Tuberculosis In Northeastern Michigan, USA

Are R. Berentsen et al. — Fri, 24 Feb 2012 12:32:28 PST

Bovine tuberculosis (bTB) is endemic in white-tailed deer (Odocoileus virginianus) in northeastern Michigan, USA, and research suggests transmission to cattle. Prevalence of the disease in deer is estimated at 1.8%, but as prevalence decreases the difficulty of detection increases. Research suggests coyotes (Canis latrans) have a higher prevalence of bTB in Michigan than deer and sampling coyotes may be a more efficient surveillance tool to detect presence or spread of the disease. Coyotes possess suitable ecological characteristics to serve as a sentinel species, assuming transmission between coyotes is not significant. The question of whether free-ranging coyotes shed Mycobacterium bovis, the causative agent of bTB, has not been previously addressed. We actively used coyotes as a sentinel to detect bTB in infected and uninfected counties in Michigan’s Northeastern Lower Peninsula. We determined whether bTB infection was present through bacteriologic culture of lymph nodes and tissues containing lesions and cultured oral/ nasal swabs and feces to establish shedding. Seventeen of 171 coyotes were M. bovis culture positive, one of which was from a previously uninfected county. All oral, nasal secretions and feces were culture negative suggesting minimal, if any, shedding of M. bovis. Thus, infection of coyotes is likely to occur through ingestion of infected deer carcasses and not from interaction with conspecifics. These findings support previous research suggesting that coyotes are useful sentinels for bTB. The use of coyotes as a sentinel, may allow wildlife managers to detect the spread of bTB into naı¨ve counties. With earlier detection managers may be able to take proactive surveillance measures to detect the disease in deer and reduce the potential risk to domestic livestock and captive deer herds.