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Broad-scale data show SARS-CoV-2 occurrence in white-tailed deer throughout much of their range in the conterminous United States and reinforce findings of considerable SARS-CoV-2 infection and exposure. Results shed light on both current infections and prior exposure, with prevalence decreasing over time and seroprevalence increasing.One-Sentence SummaryWhite-tailed deer are infected with, and have been exposed to, SARS-CoV-2 throughout their range in the conterminous US.

Rabies, a zoonotic encephalitis due to transmission of a lyssavirus, such as rabies virus (RABV), has the highest case fatality of any infectious disease. A global program for the elimination of human rabies caused by dogs is proposed for realization by 2030. Sensitive, specific, and inexpensive diagnostic tests are necessary for enhanced surveillance to detect infection, inform public health and veterinary professionals during risk assessments of exposure, and support overall programmatic goals. Multiple laboratory techniques are used to confirm a suspect case of rabies. One method for the detection of lyssavirus antigens within the brain is the direct rapid immunohistochemical test (dRIT), using light microscopy, and suitable for use under field conditions. Besides dogs, other major RABV reservoirs reside among mammalian mesocarnivores and bats. To date, use of the dRIT has been applied primarily for the diagnosis of RABV in suspect mesocarnivores. The purpose of this study was to assess the usefulness of the dRIT to the diagnosis of rabies in bats, compared to the gold-standard, the direct fluorescent antibody test (DFAT). Brains of 264 suspect bats, consisting of 21 species from Arizona and Texas, were used in the evaluation of the dRIT. The overall sensitivity of the dRIT was 100% (0.969–1.0, 95% CI) and the specificity was 94.6% (0.896–0.976, 95% CI), comparable to the DFAT. This preliminary study demonstrated the utility of the dRIT in the confirmation of RABV infection in bats. Future studies should include additional geographic, lyssavirus, and mammalian species representations for broader application during enhanced rabies surveillance, with incorporation of any potential adjustments to standard protocols, as needed.

We examined the potential for urban water sources to act as centers for rabies transmission from bats to mesocarnivores in the arid southwestern United States where free water is often limited. Because residential housing can act as den and roost sites for both mesocarnivores and bats, we also examined the effect of housing density on abundance. Using ultrasonic acoustic recorders to assess bat activity and camera traps to estimate mesocarnivore abundance, we compared 14 pairs of wet and dry locations over two years by surveying twice during the summer, once prior to summer monsoons and once during the monsoon season, when surface waters were more available. Number of calls for all bat species combined were greater at wet sites compared to dry sites and calls of two bat species often associated with rabies, big brown bat (Eptesicus fuscus) and silver-haired bat (Lasionycteris noctivagans), were recorded more at wet sites than dry sites in the monsoon season. In both years, raccoons (Procyon lotor) were photographed more often at wet sites while striped skunks (Mephitis mephitis) and gray foxes (Urocyon cinereoargenteus) were less likely to be detected at wet sites. Bat, fox and raccoon abundance was not associated with housing density while striped skunks showed a positive correlation with housing density. Higher abundance of bats at urban waters could increase potential for cross-species transmission of rabies from bats to mesocarnivores primarily for raccoons.

Bat guano is a noninvasive, data-rich genetic resource. However, the constituent bat DNA is relatively scant, degraded, and complexed with polymerase chain reaction inhibitors. It also is comingled with a rich pool of nontarget DNA from microbes, parasites, and dietary items. We designed and tested new DNA assays for bat species identification (COX1-Bat) and sex identification (XGXYC) for use with guano and other challenging samples. We reviewed previously published assays that can be used with guano samples to obtain the same species and sex data, and attempted to validate these assays for species in which they had not previously been tested. Our results demonstrate that guano-derived DNA can be used successfully to 1) identify nearly all US and Canadian bats at the species level, or to one of three Myotis species clusters, and 2) identify the sex of at least 23 US and Canadian bat species. Our newly developed assays, and validation of previously published assays, for guano-based identification of species and sex in bats, significantly enhance the power of noninvasive sampling and genetic analysis for bat studies, management, and conservation.

OBJECTIVE To evaluate species identification and rabies virus (RABV) characterization among samples from bats submitted for rabies testing in the United States and assess whether a standardized approach to specimen selection for RABV characterization could enhance detection of a sentinel event in virus dissemination among bats. SAMPLE United States public health rabies surveillance system data collected in January 2010 through December 2015. PROCEDURES The number of rabies-tested bats for which species was reported and the number of RABV-positive samples for which virus characterization would likely provide information regarding introduction of novel RABV variants and translocation and host-shift events were calculated. These specimens were designated as specimens of epizootiological importance (SEIs). Additionally, the estimated test load that public health laboratories could expect if all SEIs underwent RABV characterization was determined. RESULTS Species was reported for 74,928 of 160,017 (47%) bats submitted for rabies testing. Identified SEIs were grouped in 3 subcategories, namely nonindigenous bats; bats in southern border states, Florida, Puerto Rico, and the US Virgin Islands; and bats of species that are not commonly found to be inflected with RABV. Annually, 692 (95% CI, 600 to 784) SEIs were identified, of which only 295 (95% CI, 148 to 442) underwent virus characterization. Virus characterization of all SEIs would be expected to increase public health laboratories’ overall test load by 397 (95% CI, 287 to 506) samples each year. CONCLUSIONS AND CLINICAL RELEVANCE Species identification and RABV characterization may aid detection of a sentinel event in bat RABV dissemination. With additional resources, RABV characterization of all SEIs as a standardized approach to testing could contribute to knowledge of circulating bat RABV variants.

Mexican wolves (Canis lupus baileyi) share their range with a number of sympatric carnivores, many of which are a concern to livestock producers because they can prey on livestock. Determining which predator species is responsible for killing livestock is important for determining appropriate management actions and for the conservation of Mexican wolves. A variety of information can be used to decipher which carnivore species was responsible for making a kill, and mandibular (upper) and maxillary (lower) intercanine width measurements (i.e., bite mark analysis) can aid this process. No research has been conducted to validate the usefulness of bite mark analysis; thus, we used dentition measurements from Mexican wolves, coyotes (Canis latrans), feral dogs (Canis familiaris), bobcats (Lynx rufus), mountain lions (Puma concolor), and gray foxes (Urocyon cinereoargenteus) and an overlap coefficient to evaluate the degree of overlap in intercanine width between these species. We found that larger carnivore species had greater overlap than smaller carnivores, feral dogs overlapped widely with all the medium-to-large carnivores, and upper and lower intercanine width measurements provided similar information. Our data indicated that when investigating livestock depredations for Mexican wolves, bite mark analyses should be evaluated along with additional forensic evidence due to the overlap between many of the carnivore species, and that measurements between 28 and 35 mm have the greatest uncertainty because this range overlaps with feral dogs, mountain lions, and coyotes.

Aim Predation on livestock is one of the primary concerns for Mexican wolf (Canis lupus baileyi) recovery because it causes economic losses and negative attitudes toward wolves. Our objectives were to develop a spatial risk model of cattle depredation by Mexican wolves in the USA portion of their recovery area to help reduce the potential for future depredations. Location Arizona and New Mexico, USA. Methods We used a presence-only maximum entropy modeling approach (Maxent) to develop a risk model based on confirmed depredation incidents on public lands. In addition to landscape and human variables, we developed a model for annual livestock density using linear regression analysis of Animal Unit Month (AUM), and models for abundance of elk (Cervus canadensis), mule deer (Odocoileus hemionus) and white-tailed deer (Odocoileus virginiana) using Maxent, to include them as biotic variables in the risk model. We followed current recommendations for controlling model complexity and other sources of bias. Results The primary factors associated with increased risk of depredation by Mexican wolf were higher canopy cover variation and higher relative abundance of elk. Additional factors with increased risk but smaller effect were gentle and open terrain, and greater distances from roads and developed areas. Main conclusions The risk map revealed areas with relatively high potential for cattle depredations that can inform future expansion of Mexican wolf distribution (e.g., by avoiding hotspots) and prioritize areas for depredation risk mitigation including the implementation of active non-lethal methods in depredation hotspots. We suggest that livestock be better protected in or moved from potential hotspots, especially during periods when they are vulnerable to depredation (e.g. calving season). Our approach to create natural prey and livestock abundance variables can facilitate the process of spatial risk modeling when limitations in availability of abundance data are a challenge, especially in large-scale studies.

Interspecific interactions among mesocarnivores can influence community dynamics and resource partitioning. Insights into these interactions can enhance understanding of local ecological processes that have impacts on pathogen transmission, such as the rabies lyssavirus. Host species ecology can provide an important baseline for disease management strategies especially in biologically diverse ecosystems and heterogeneous landscapes. We used a mesocarnivore guild native to the southwestern United States, a regional rabies hotspot, that are prone to rabies outbreaks as our study system. Gray foxes (Urocyon cinereoargenteus), striped skunks (Mephitis mephitis), bobcats (Lynx rufus), and coyotes (Canis latrans) share large portions of their geographic ranges and can compete for resources, occupy similar niches, and influence population dynamics of each other. We deployed 80 cameras across two mountain ranges in Arizona, stratified by vegetation type. We used two-stage modeling to gain insight into species occurrence and co-occurrence patterns. There was strong evidence for the effects of elevation, season, and temperature impacting detection probability of all four species, with understory height and canopy cover also influencing gray foxes and skunks. For all four mesocarnivores, a second stage multi-species co-occurrence model better explained patterns of detection than the single-species occurrence model. These four species are influencing the space use of each other and are likely competing for resources seasonally. We did not observe spatial partitioning between these competitors, likely due to an abundance of cover and food resources in the biologically diverse system we studied. From our results we can draw inferences on community dynamics to inform rabies management in a regional hotspot. Understanding environmental factors in disease hotspots can provide useful information to develop more reliable early-warning systems for viral outbreaks. We recommend that disease management focus on delivering oral vaccine baits onto the landscape when natural food resources are less abundant, specifically during the two drier seasons in Arizona (pre-monsoon spring and autumn) to maximize intake by all mesocarnivores.

Rabies is responsible for an estimated 59,000 human deaths worldwide, and domestic dogs are the primary reservoir and vector of the disease. Among some nations, widespread vaccination has led to elimination of rabies in domestic dogs, yet dogs are still susceptible to rabies infection from interactions with wildlife reservoirs. On Tribal lands in the United States, less than 20% of domestic dogs are vaccinated for rabies, and parenteral vaccination is often unfeasible. Oral rabies vaccination may provide a solution, but a suitable bait flavor and vaccine must be identified. We evaluated 5 bait flavors (bacon, cheese, egg, fish, and sweet) in pairwise flavor-preference trials using placebo Ultralite baits in 26 domestic dogs on the Navajo Nation, Arizona. Each bait flavor was offered a total of 104 times. In all paired comparisons, bacon was more frequently preferred to the alternative. The sweet flavor (the flavor used operationally for oral rabies vaccine (ORV) distribution in Canada) was least preferred. Forty domestic dogs were offered baits containing ONRAB ORV: 14 received the sweet-flavored bait packet and 26 received bacon-flavored baits. Serum was collected from dogs before vaccination and at day 14 and 30 or 37 days after vaccination. Thirty-seven dogs consumed the baits, 2 baits (both sweet flavored) were chewed and spit out, and 1 (sweet flavored) was swallowed without apparent chewing (gulped). Eight dogs had preexisting rabies virus neutralizing antibody (RVNA) titers and 13 naive dogs failed to seroconvert during the study period. Overall, 27 dogs (67.5%) showed increased RVNA titers after vaccination, including 1 dog who chewed and spit out the bait and all dogs with positive baseline RVNA titers. Geometric mean titers for all dogs that seroconverted during the study period peaked at day 14 (1.2 IU/mL; n = 24) and decreased slightly by the final sampling day (0.8 IU/mL; n = 27). We conclude that bacon flavor may be a suitable bait flavor for ORV distribution in loosely kept or free-roaming domestic dogs. Seroconversion among dogs who ingested ONRAB-filled baits was variable. Why 13 dogs who consumed ORV baits failed to seroconvert remains unknown. Additional research to improve seroconversion rates in domestic dogs after vaccination with ONRAB is recommended.

Determining social contacts among solitary carnivores is difficult given their often nocturnal and secretive nature. We used proximity-sensing radiocollars to quantify social contacts and den sharing among striped skunks (Mephitis mephitis) in suburban Flagstaff, Arizona, United States, in summer, autumn, and winter 2012–2013. During June and July, we followed 6 males and 5 females and, in spite of overlapping home ranges, they had few social contacts (range = 0–7), and all were brief, nocturnal encounters. From October through February, we followed 8 males and 9 females and found that patterns of contacts were similar for males and females except for significantly higher diurnal contacts (co-denning) among females in winter. Females varied in denning behavior; 1 female denned continuously in the same location from early November to late January, while at the other extreme 1 female moved among 10 different dens across the same time period. Several females moved to new communal dens in late January, resulting in new combinations of females co-denning. Males visited multiple female dens throughout winter. Overall, our data were consistent with previous studies in documenting overlapping home ranges of both sexes with few social contacts in summer, male intolerance but lack of male territoriality, and divergent social behavior in winter, with females co-denning while males generally denned alone. Our study differed from others in documenting more social interaction and movement during winter, often through nocturnal visits by males to female dens, and a shift in denning associations among females near the end of January.

Cat food left out for feral and domestic cats and bird seed spilled from backyard bird feeders are two common anthropogenic food sources that may attract non-target animals like urban mesocarnivores but no studies have quantified mesocarnivore visitation at these food sources. We used motion-activated video cameras to monitor mesocarnivore use of spilled bird seed below 25 bird feeders maintained by residents in four neighborhoods in Flagstaff, Arizona, June-September 2012 and 2014. During the first five nights of monitoring only seed that spilled naturally below feeders was available. On each of the subsequent five nights, we placed a bowl of commercially available dry cat food below feeders so that both spilled seed and cat food were present. In both years, after cat food was added, the number of visits by striped skunks (Mephitis mephitis), raccoons (Procyon lotor) and domestic cats (Felis cattus) doubled and the number of times two animals were present simultaneously also increased. Aggressive interactions, in the form of displays or contacts, increased for all species combinations but significantly only between skunks in the presence of cat food. These results demonstrate that both spilled bird seed and cat food may be exploited frequently by urban mesocarnivores and that the type of food can elicit different behavioral responses that could have important implications for human-wildlife conflict and disease transmission.

Mass parenteral vaccination remains the cornerstone of dog rabies control. Oral rabies vaccination (ORV) could increase vaccination coverage where free-roaming dogs represent a sizeable segment of the population at risk. ORV's success is dependent on the acceptance of baits that release an efficacious vaccine into the oral cavity. A new egg-flavored bait was tested alongside boiled bovine intestine and a commercially available fishmeal bait using a hand-out model on the Navajo Nation, United States, during June 2016. A PVC capsule and biodegradable sachet were tested, and had no effect on bait acceptance. The intestine baits had the highest acceptance (91.9%; 95% confidence interval (CI), 83.9%⁻96.7%), but the fishmeal (81.1%; 95% CI, 71.5%⁻88.6%) and the egg-flavored baits (77.4%; 95% CI, 72.4%⁻81.8%) were also well accepted, suggesting that local bait preference studies may be warranted to enhance ORV's success in other areas where canine rabies is being managed. Based on a dyed water marker, the delivery of a placebo vaccine was best in the intestine baits (75.4%; 95% CI, 63.5%⁻84.9%), followed by the egg-flavored (68.0%; 95% CI, 62.4%⁻73.2%) and fishmeal (54.3%; 95% CI, 42.9%⁻65.4%) baits. Acceptance was not influenced by the supervision or ownership, or sex, age, and body condition of the dogs. This study illustrates that a portion of a dog population may be orally vaccinated as a complement to parenteral vaccination to achieve the immune thresholds required to eliminate dog rabies.

Significantly more (54%, P=0.003) placebo baits placed under 26 bird feeders in Arizona, US were removed by striped skunks (Mephitis mephitis) than at paired, nonfeeder locations (19%). Baiting at bird feeders could supplement traditional oral rabies vaccine bait placement in urban-suburban areas while engaging the public in rabies control efforts.

Rabies, an acute progressive encephalomyelitis caused by viruses in the genus Lyssavirus, is one of the oldest known infectious diseases. Although dogs and other carnivores represent the greatest threat to public health as rabies reservoirs, it is commonly accepted that bats are the primary evolutionary hosts of lyssaviruses. Despite early historical documentation of rabies, molecular clock analyses indicate a quite young age of lyssaviruses, which is confusing. For example, the results obtained for partial and complete nucleoprotein gene sequences of rabies viruses (RABV), or for a limited number of glycoprotein gene sequences, indicated that the time of the most recent common ancestor (TMRCA) for current bat RABV diversity in the Americas lies in the seventeenth to eighteenth centuries and might be directly or indirectly associated with the European colonization. Conversely, several other reports demonstrated high genetic similarity between lyssavirus isolates, including RABV, obtained within a time interval of 25–50 years. In the present study, we attempted to re-estimate the age of several North American bat RABV lineages based on the largest set of complete and partial glycoprotein gene sequences compiled to date (n = 201) employing a codon substitution model. Although our results overlap with previous estimates in marginal areas of the 95 % high probability density (HPD), they suggest a longer evolutionary history of American bat RABV lineages (TMRCA at least 732 years, with a 95 % HPD 436–1107 years). Electronic supplementary material The online version of this article (doi:10.1007/s11262-013-0952-9) contains supplementary material, which is available to authorized users.

Multiple species of bats are reservoirs of rabies virus in the Americas and are occasionally the source of spillover infections into mesocarnivore species. Although rabies transmission generally is assumed to occur via bite, laboratory studies have demonstrated the potential for rabies transmission via ingestion of rabid animals. We investigated the ecological potential for this mode of transmission by assessing mesocarnivore scavenging behavior of dead bats in suburban habitats of Flagstaff, Arizona, US. In autumn 2013, summer 2014, and autumn 2015, we placed 104 rabies-negative bat carcasses either near buildings, in wildland areas, or in residential yards and then monitored them with trail cameras for 5 d. Overall, 52 (50%) bat carcasses were scavenged, with 39 (75%) of those scavenged by striped skunks ( Mephitis mephitis ). Within our study area, striped skunks had a higher ecological potential to contract rabies via ingestion of bat carcasses compared to other mesocarnivore species, due both to a greater number of encounters and a higher probability of ingestion per encounter (91%), and they were significantly more likely to approach bat carcasses in yards than in wildland areas. Raccoons ( Procyon lotor ) and gray foxes ( Urocyon cinereoargenteus ) had fewer encounters (nine and 13, respectively) and lower probability of ingesting bats (33% and 8%, respectively).

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. Published by Elsevier Ltd.

Less than 20% of the domestic dogs on tribal lands in the United States are vaccinated against rabies. One method to increase vaccination rates may be the distribution of oral rabies vaccines (ORVs). ONRAB® (Artemis Technologies, Inc., Ontario, Canada) is the primary ORV used in Canada to vaccinate striped skunks and raccoons. To investigate the potential use of ONRAB® ORV baits to vaccinate feral domestic dogs against rabies on tribal lands and beyond, we performed a flavor preference study. A total of 7 bait flavors (bacon, cheese, dog food, hazelnut, sugar-vanilla, peanut butter, and sardine) were offered in pairs to 13 domestic dogs. Each dog was offered all possible combinations of bait pairs over a period of 10 days, with each bait offered 6 times. The proportion of times each bait was consumed first by individual dogs was calculated and comparisons among dogs were conducted using the MIXED procedure in SAS (SAS Institute, Cary, NC). Pairwise comparisons between baits were performed using “contrast” statements with sugar-vanilla flavor as the default for comparison. Type 3 tests of fixed effects showed a significant treatment effect (F6,72 = 9.74, P

Dispersal and long-term monitoring of beaver Castor canadensis and C. fiber populations has been hampered by the inability to retain external transmitters on the animals and the limited range of internal transmitters. We tested several transmitter designs to develop an effective and reliable external transmitter for beavers. A modified ear-tag transmitter fitted with a plastic sleeve and attached to the tail was found efficacious in pen trials. We captured and tagged 31 beavers in Phoenix, Arizona, USA, to further test these modified ear-tag transmitters in the field. Retention of the sleeve transmitter averaged 343.5 days±44.2 (SE), more than triple the time previously reported. The addition of neoprene washers to the underside of the tail increased retention to 89%. Long-term monitoring of beaver populations may now be possible with increased retention of transmitters with the addition of neoprene washers.

Vigilant behavior in wild ungulates is critical to guard against predation. However, few studies have examined vigilant behavior in domesticated ungulates. Considering the expansion of large predator populations, understanding vigilant behavior and factors that influence it will help with the management of livestock. We observed adult female cattle (Bos taurus L.) in open-range conditions where large predators (wolves [Canis lupus L.] and mountain lions [Puma concolor (L.).]) were common threats during summers of 2005 and 2006 in eastern Arizona. This study was designed to determine 1) to what extent cattle exhibit vigilant behavior compared to published data on wild ungulates, 2) whether predation events influence vigilance rates of cattle, and 3) whether social and environmental factors affect vigilance of cattle. Cattle exhibited vigilant behavior (3% ± 0.19%) during peak foraging periods, but at a lower rate than wild ungulates. Cows with calves were more than twice as vigilant (4.5% ± 0.46%)...

Mexican gray wolves were reintroduced into New Mexico and Arizona in 1998. When wolves kill a producing cow, ranchers in the region are eligible to receive an indemnity payment equal to the market value of the lost animal. We developed a model that allows estimation of the present value of the revenue stream that a cow or herd p rovides and find that if a producing cow is killed, the decrease in the present value of the rancher's revenue stream is about $1,230. Mean indemnity payments are currently $1,000, implying ranchers are not being sufficiently compensated. KEY W ORDS : Arizona, Canis lupus baileyi, cow-calf operations, economic valuation, indemnity, livestock predation, Mexican gray wolf, New Mexico, predation, wolf Proc. 26 th Vertebr. Pest Conf. (R. M. Timm and J. M. O'Brien, Eds.) Published at Univ. of Calif., Davis. 2014. Pp. 413-418.

Author(s): Johnson, Terry B.; Rocke, Tonie E.; Gober, Pete; Van Pelt, Bill E.; Miller, Michael W.; Tripp, Daniel W.; Abbott, Rachel C. C.; Bergman, David L. | Abstract: The Black-footed Ferret Recovery Implementation Team Executive Committee is conducting a project to develop, and (hopefully) eventually implement, a plague vaccination program for prairie dogs. The project is a component of the Western Association of Fish and Wildlife Agencies Grasslands Conservation Initiative. An effective, field-worthy vaccine against plague could be the biggest breakthrough in recovery efforts for the black-footed ferret since the 1981 rediscovery of wild ferrets near Meeteetse, Wyoming. If proven efficacious, the vaccine could help agencies and stakeholder cooperators maintain specific populations of prairie dogs at robust levels, thus enhancing range-wide conservation of those species, as well recovery of the ferret, while enabling control of other prairie dog populations to resolve site-specific agricultural and human health concerns. The results of laboratory and field-testing in the early stages of developing this vaccine are preliminary but mostly encouraging. A plan for broad-scale application is being developed for possible use when testing has been completed and (if warranted) the vaccine is registered for governmental use. An overview of all aspects of the project is discussed.

From 20 August to 19 September 1993 and 1994, we assessed the effects of treating ripening sunflower fields with DRC-1339-treated rice baits on blackbird (Icterinae) damage to sunflower fields found within ⩽ 3.2 km of blackbird roosts. The number of blackbirds ( x = 18,943 ± 1,888 ) using roosts centered within the treated and untreated test areas were similar (P = 0.432). The number of blackbirds using sunflower fields in the test areas did not vary among days after treatment (P = 0.538) or between treated and untreated areas (P = 0.203, averaging 3203 ± 361). The percentage of sunflower damage did not differ (P = 0.736) between treatments ( x = 2.3 ± 0.6% ). It appears broadcasting DRC-1339-treated rice baits in ripening sunflower fields does not reduce local blackbird populations or sunflower damage.

The effects of glyphosate herbicide-induced changes in wetland emergent vegetation (largely cattails,Typha spp.) on densities of ducks (Anatinae) were assessed in northeastern North Dakota. In 1990 and 1991, 17 cattail-dominated wetlands were randomly assigned to 0% (reference wetlands), 50%, 70%, or 90% areal spray coverages with glyphosate herbicide. Densities of green-winged teal (Anas crecca), bluewinged teal (Anas discors), gadwalls (Anas strepera), and ruddy ducks (Oxyura jamaicensis) were similar among treatments during both post-treatment years (P≥0.1). One year post-treatment, mallard (Anas platyrhynchos) and northern pintail (Anas acuta) abundances did not differ among treatments (P≥0.1), whereas two years post-treatment their abundances were greater in the sprayed wetlands than in the reference wetlands (P≤0.1). Densities of northern shovelers (Anas clypeata) and redheads (Aythya americana) differed among treatments in both post-treatment years, with the 50% sprayed wetlands harboring more ducks than did the other three treatments. Percent coverage and hectares of open water were positively correlated with numbers of diving ducks (Aythyini and Oxyurini) (P≤0.1). Dabbling duck (Anatini and Cairinini) numbers correlated positively with hectares of open water and dead vegetation, whereas their numbers were negatively correlated with percent coverage of live vegetation (P≤0.1). Results of this study suggest that numbers of ducks were positively influenced by creating a mosaic of open water, live vegetation, and dead vegetation with glyphosate herbicide.

In August 1992, we treated cattail-dominated wetlands in four 23-km2 blocks with aerially-applied glyphosate herbicide (5.3 1 ha−1). Four other blocks of wetlands were left untreated (reference). We assessed the effects of cattail (Typha spp.) reduction on roosting blackbird (Icterinae) numbers and sunflower damage within the blocks. Blackbird numbers did not differ between posttreatment years (P = 0.453) or between treated and reference wetlands (P = 0.469), averaging 6227 ± 4185 (SE) birds per block. Sunflower damage within blocks was similar between posttreatment years (P = 0.250) and did not vary (P = 0.460) between treatments ( x = 2.9 ± 1.2% ). However, positive linear relationships were detected between blackbird numbers (y) and hectares of live cattails (x) [(y = 442.2 x)] (P = 0.006) and between blackbird numbers (x) and kilograms of sunflower lost per hectare per year (y) [(y = 0.003 x)] (P = 0.0001). Cattail reduction appears to discourage roosting blackbirds and, thus, may reduce sunflower damage in adjacent fields.

We offered sunflower meats, cracked corn and brown rice to individuals and small groups ( n = 4–5) of red-winged blackbirds ( Agelaius phoeniceus ), yellow-headed blackbirds ( Xanthocephalus xanthocephalus ) and common grackles ( Quiscalus quiscula ) to determine their food preference. Common grackles (sexes combined) preferred cracked corn over sunflower meats and brown rice. Male and female yellow-headed blackbirds preferred brown rice or a combination of brown rice and cracked corn or sunflower meats. Female red-winged blackbirds chose brown rice; whereas, male red-winged blackbirds did not show a consistent food preference. Either brown rice or a brown rice and cracked corn combination should be used to bait blackbirds.

Author(s): Maestas, Jesse M.; Theimer, Tad C.; Hausig, Krista M.; Bergman, David L. | Abstract: Potentially fatal wildlife diseases like rabies are of increasing concern, due to human effects on the environment that could alter wildlife behavior and population dynamics in ways that increase disease prevalence. Wildlife population abundance is a key factor, affecting both disease outbreak and rate of disease spread, and understanding how population abundance changes across landscapes is crucial for developing predictive models to control and manage wildlife diseases. We investigated how urbanization in Flagstaff, AZ influenced skunk population abundance by simultaneously trapping 6 pairs of suburban and wildland study sites for 200 trap-nights between June and September 2011. The number of unique skunks captured at the 6 suburban locations ranged from 3-14 (mean = 6.5) while the number trapped at the 6 wildland sites ranged from 0-2 (mean = 0.5). We also reviewed data gathered as part of the trap-vaccinate-release (TVR) program carried out from 2004-2010 by USDA APHIS Wildlife Services to estimate population sizes and the percentage of the population vaccinated. Our estimates of the percentage of the population vaccinated in any one year ranged from 11%-23%, below percentages reported in the literature as necessary to prevent disease spread. Overall, these data indicate that the potential for disease spread was greatest within the suburban matrix and relatively low in surrounding wildlands and that intensified annual TVR programs would be necessary to maintain high enough percentages of immunized animals to achieve effective herd immunity.

Parenteral vaccination campaigns are integral to the elimination of canine rabies. To maximize herd immunity in dogs, immunocontraception provided at the time of rabies vaccination should reduce fecundity and dog abundance. GonaCon has been used successfully as an immunocontraceptive in a variety of mammals, and by inference, the dog would be an ideal candidate for testing. As an initial step in evaluating a combination-vaccination program, we assessed the effects of GonaCon on rabies virus neutralizing antibody production in dogs after administration of a veterinary rabies vaccine. Eighteen feral/free ranging dogs were included in this initial study: six were given GonaCon only, six were given rabies vaccination only, and six received GonaCon and rabies vaccination. Antibody levels were evaluated over 82 days. The use of the immunocontraceptive GonaCon did not affect the ability of dogs to seroconvert in response to the rabies vaccine. Thus, GonaCon provides a potential immunocontraceptive for use in combination with rabies vaccine to increase herd immunity and address dog population over abundance to better manage rabies.

We followed radio-collared striped skunks (Mephitis mephitis) from January 2004-December 2005 in two urban areas of Flagstaff, Arizona, USA to determine seasonal patterns of movement and home-range size. We also used automated cameras to determine the potential for inter- and intraspecific interaction at skunks' diurnal resting sites and nocturnal focal locations. We found no difference between sexes in nightly rates of travel or in size of seasonal home range. Nightly rates of travel were greatest in the postbreeding months (May-July) and smallest from November to February, consistent with larger home ranges (95% kernel estimates) from March-August and smaller home ranges from September-February. Sixty-three percent of monitored males and 38% of monitored females crossed the urban-wildland interface, in at least one direction on at least one night, and some remained outside the urban area for days or weeks, indicating that skunks could act as vectors of disease across the urban-wildland interface. We recorded co-occurrence of skunks with domestic cats (Felis domesticus), raccoons (Procyon lotor), gray foxes (Urocyon cinereoargenteus), and other skunks at focal locations and diurnal retreats used by skunks, suggesting these areas are potential sites for both inter- and intraspecific rabies transmission and could be targeted by wildlife managers during trapping or vaccination programs.

Wild and domestic ungulates modify their behaviour in the presence of olfactory and visual cues of predators but investigations have not exposed a domestic species to a series of cues representing various predators and other ungulate herbivores. We used wolf (Canis lupus), mountain lion (Puma concolor), and mule deer (Odocoileus hemionus) stimuli (olfactory and visual), and a control (no stimuli) to experimentally test for differences in behaviour of cattle (Bos taurus) raised in Arizona. We measured (1) vigilance, (2) foraging rates, (3) giving up density (GUD) of high quality foods and (4) time spent in high quality forage locations in response to location of stimuli treatments. In general, we found a consistent pattern in that wolf and deer treatments caused disparate results in all 4 response variables. Wolf stimuli significantly increased cattle vigilance and decreased cattle foraging rates; conversely, deer stimuli significantly increased cattle foraging rate and increased cattle use of high quality forage areas containing stimuli. Mountain lion stimuli did not significantly impact any of the 4 response variables. Our findings suggest that domestic herbivores react to predatory stimuli, can differentiate between stimuli representing two predatory species, and suggest that cattle may reduce antipredatory behaviour when near heterospecifics.

Management for beaver now ranges from lethal removal of nuisance individuals to reintroduction of individuals for wetland restoration and to increase wildlife and habitat diversity. Management, or lack thereof, is driven largely by stakeholder concerns at the local and regional level. In many cases with management of beaver and other species, there are unclear visions of how wildlife populations may exploit resources after successful restoration or with changing landscape conditions (e.g., habitat quality and competition). With increasing conversion of the modern-day landscape, natural resource managers must make pragmatic decisions on the potential effects habitat alteration has on system stability. In 2000, the United States Army Corps of Engineers received approval from Congress to construct the Tres Rios Ecosystem Restoration and Flood Control Project in Phoenix, Arizona. Upon completion, this multi-phased, 7-mile (11.3-km), 1,500-acre (607-ha) project is designed to include a 4.25- mile (6.8-km) flood protection levee, an effluent pump station, and development/maintenance of emergent wetlands, riparian corridors, and open water marshes to replace existing non-native saltcedar. In 2000, Tres Rios constructed a demonstration area on- site that used reclaimed wastewater from the 91 st Avenue Treatment Plant to establish wetland habitat. Simultaneously, we began the Tres Rios Beaver Research Project to determine the possible effects beaver have on riparian and wetland habitats. Studies within this project found that existing non-lethal management techniques were generally ineffective; however, topical application of fructose and polyethylene glycol showed promise as a technique to increase palatability of invasive Tamarisk spp., while palatability of native tree species could be reduced by application of an herbivore repellent. Other studies developed new techniques for anesthetizing beaver and increasing radio transmitter retention time on beaver. Through monitoring movement of beaver and using landscape genetic techniques to explore population diversity, researchers found deviations from published literature on beaver, suggesting that density-dependent factors may be driving beaver behavior and movement in this environment. We describe the planning process involved in developing these research studies to address stakeholder concerns.

Author(s): Manzo, Amanda; Theimer, Tad; Delph, Robert; Hall, John; Hernandez, Nancy; Holt, Brandon; Maloney, Maureen; Moreno, Mayra; Bergman, David; Heuser, Chad | Abstract: Delivery of oral rabies vaccine can be an effective method for combating rabies, but broadcasting vaccine sachets over wide areas creates the potential for non-target species to ingest vaccine baits before the target species encounters them. An alternative is to present the vaccine at a bait station designed to allow access by target species, while excluding some non-target species. We tested whether bait stations constructed of PVC pipe of 3 different diameters (10, 15, and 20 cm) differed in their effectiveness in allowing access by striped skunks versus other, non-target, nocturnal mammals in the urban environment of Flagstaff, Arizona. We placed bait stations in sets of 3 at 13 locations during late February and early March 2005 and monitored their use for 5 nights using digital still cameras. We recorded visits by striped skunks, gray foxes, raccoons, and domestic cats and dogs. Large-diameter tubes were used by all species, though large dogs had limited access, and small-diameter tubes were entered only once (by a skunk). Medium-diameter stations were used by all species except dogs, but skunks entered these stations more readily (81% vs. 44% or less), indicating that baits in 15-cm tubes would be more readily accessed by skunks. If striped skunks are the primary target species, we recommend the use of medium-diameter bait stations, as these stations excluded all dogs and reduced bait uptake by cats, foxes, and raccoons. If foxes and raccoons are also targeted, large-diameter stations will be required, and these will be available to all cats and some small dogs but should exclude larger dogs. Given the cost of this type of bait station in both time and money, we recommend their use only in limited areas where potential interaction with non-target species is of special concern. However, when one considers the value of human life, the cost may be negligible.

Three population monitoring methods were evaluated in support of a trap/vaccinate/release program for controlling a bat variant of rabies virus in skunks (Mephitis mephitis) in Flagstaff, Arizona (USA). Skunks were the primary species targeted for population monitoring during the program, but feral cats were also monitored as they represented an abundant secondary vector species capable of rabies transmission. Skunks were vaccinated and released, except for a subset tested for rabies. All captured cats were placed in the local animal shelter. Spotlight surveys essentially did not detect skunks, and were not able to detect reductions in the cat population. Catch-per-unit-effort marginally tracked population trends, but a passive track index adapted for an urban setting was most sensitive for detecting changes in skunk and cat populations. Mark-recapture population estimates could not be validly calculated from the data on captures and recaptures due to multiple violations of analytical assumptions.

Author(s): Linz, George M.; Barras, Amy E.; Sawin, Richard A.; Homan, H. Jeffrey; Bergman, David L.; Bleier, William J. | Abstract: We conducted studies from 1994 to 1999 in eastern South Dakota to determine the best strategy for baiting spring-migrating blackbirds. From 26 March to 14 April, male and female red-winged blackbirds made-up 61% and 17% of the roost population, respectively. After the 14th of April, the population consisted of 32% male and 49% female red-winged blackbirds. Blackbird migration in eastern South Dakota generally ended by late April. Habitat use studies conducted in March and April 1994, 1995, and 1998 showed that blackbirds used corn stubble for foraging and woodlots/shelterbelts for loafing. We concluded that bait plots located in corn stubble adjacent to wooded areas could attract large numbers of red-winged blackbirds during spring migration.

Author(s): Bergman, David L.; Huffman, Louis E.; Paulson, John D. | Abstract: Beginning in July 1991, the North Dakota Game and Fish Department authorized the use of funds in a cost-share program to assist farmers and ranchers with the implementation of nonlethal methods to protect livestock. Fund expenditures are administered and approved by the U.S. Department of Agriculture, Animal and Plant Health Inspection Service, Wildlife Services, North Dakota program. The program provides a 50:50 cost-share up to a maximum of $150 per purchase of nonlethal items for the protection of livestock from predation. During the six year period from July 1991 to July 1997, the program has cost-shared dogs, donkeys, electronic guards, and llamas. The Great Pyrenees dog breed was the method most frequently selected.

Blackbird (Icterinae) damage to sunflowers in the northern Great Plains can be locally severe. One approach to alleviating depredation pressure is to reduce blackbird populations through application of brown rice bait treated with the avicide DRC-1339. Because such baiting can potentially affect nontarget species, we conducted pen and field trials to evaluate the potential risk from avicide baiting to ring-necked pheasants (Phasianus colchicus). Although most female pheasants in pen tests preferred cracked corn and sorghum, 2 of 12 birds preferred brown rice. In 4-day trials within a 0.2-ha flight pen, pheasant consumption of brown rice from bait swaths simulating field bait applications was not affected by the presence of an alternate bait swath of cracked corn. Pen trials to evaluate possible avoidance responses following a sublethal dose of DRC-1339 showed that 2 of 7 birds shifted from their previously preferred feeding sites following exposure to the avicide. During March and April 1995, we recorded pheasant numbers in 6 pairs of 0.8-ha plots in corn stubble fields that were either baited with brown rice or were designated as reference plots. Overall, use of test plots was low, but at the most heavily used sites, pheasants visited reference plots more than baited plots (P = 0.004). We conclude that (1) pheasants will eat brown rice treated with DRC-1339; and (2) although chances of exposure to an acute lethal dose can be reduced by increasing the dilution, harmful repeated doses could be obtained because avoidance of feeding sites, following sublethal exposure, cannot be assumed.