Fort Collins, CO, United States
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Dwyer J.F.,EDM International Inc. | Cockwell S.G.,Falklands Conservation
Journal of Raptor Research | Year: 2011

On the Falkland Islands (Malvinas), raptors historically were perceived as a threat to livestock, and consequently were widely persecuted through the mid-twentieth century. Conservation measures now minimize persecution and have facilitated increases in raptor populations, but the ecology of raptors on the Falkland Islands (Malvinas) remains poorly understood. We investigated social hierarchies within an assemblage of nonmigratory raptorial scavengers: Variable Hawk (Buteo polyosoma), Striated Caracara (Phalcoboenus australis), Southern Caracara (Caracara plancus), and Turkey Vulture (Cathartes aura jota). During thirty observation sessions of 30 min each, we recorded 1386 aggressive interactions involving one or more of these species. We found that Variable Hawks were aggressors in 98% (95% CI = 96-100%) of interactions with Striated Caracaras, 82% (69-95%) of interactions with Turkey Vultures, and 80% (72-88%) of interactions with Southern Caracaras. Southern Caracaras were aggressors in 100% of interactions with Striated Caracaras, and 90% (80-100%) of interactions with Turkey Vultures. Turkey Vultures were aggressors in 71% (61-82%) of interactions with Striated Caracaras. Within species, we found adult Southern Caracaras were aggressors in 78% (72-84%) of interactions with conspecific juveniles and 76% (68-85%) of interactions with conspecfic subadults. Adult Striated Caracaras were aggessors in 100% of interactions with conspecific juveniles and 97% (91-100%) of interactions with conspecfic subadults. Predicted patterns of size-based dominance typical of complex African and South American avian scavenger assemblages were not observed in the relatively simple assemblage of the Falkland Islands (Malvinas), but we did observe single-species groups of up to 83 Southern Caracaras and 42 Striated Caracaras. © 2011 The Raptor Research Foundation, Inc.

Harness R.E.,EDM International Inc. | Juvvadi P.R.,Raptor Conservation Foundation
IEEE Industry Applications Magazine | Year: 2015

In December 2011, we visited distribution pole lines in the Thar Desert in western India to assess the electrocution risk to raptors. We inspected 624 concrete poles and found 160 bird carcasses at the pole bases. Although power lines can provide positive benefits for birds, the trend of using concrete poles with metal crossarms outweighs the benefits. If concrete poles are used in raptor habitats, alternative construction methods should be substituted, such as the use of suspended insulators. © 1975-2012 IEEE.

Dwyer J.F.,Virginia Polytechnic Institute and State University | Dwyer J.F.,EDM International Inc. | Morrison J.L.,Trinity College at Hartford | Fraser J.D.,Virginia Polytechnic Institute and State University
Journal of Wildlife Management | Year: 2012

Management of crested caracaras (Caracara cheriway), focuses on nests identified during surveys. If no nests are found, management can be suspended. Thus, false negatives can have substantial consequences. We surveyed 49 breeding territories to assess factors with the potential to cause false negatives in detecting nests of crested caracaras and in observing adult birds. The probability that a nest would be detected on any given visit increased by about 0.5% for each hour of observer experience up to about 70 hours (our maximum). Experience did not affect the probability of observing an adult. The probability of detecting a caracara nest or observing an adult caracara decreased by 2.0-3.5% each hour after sunrise that a visit began. If visibility during any portion of a visit was obscured by fog or rain, the probability of detecting a nest decreased by as much as 60%, and the probability of observing an adult caracara decreased by about 50%. We provide a tool managers can use to calculate the likelihood of successful surveys. We recommend that managers disregard negative results from surveys conducted under conditions that are unlikely to yield positive results, and repeat those surveys under better conditions. © 2011 The Wildlife Society.

Smith J.A.,University of Nebraska - Lincoln | Smith J.A.,Virginia Polytechnic Institute and State University | Dwyer J.F.,EDM International Inc.
Condor | Year: 2016

Energy infrastructure is widespread worldwide. Renewable energy technologies, which are expanding their footprint on the landscape and their contribution to energy availability, represent a different kind of infrastructure from extractive energy technologies. Although renewable energy sources may offer a 'greener alternative' to traditional extractive energy sources, mounting evidence suggests that renewable energy infrastructure, and the transmission lines needed to convey energy from renewable energy facilities to users, may impact birds. Peer-reviewed literature historically has focused on the direct effects of electrocution and, to a lesser extent, collisions with overhead power systems, and on avian collisions at wind energy facilities, with less consideration of indirect effects or other energy sectors. Here, we review studies that have examined direct and indirect effects on birds at utility-scale onshore windand solar-energy facilities, including their associated transmission lines. Although both direct and indirect effects appear site-, species-, and infrastructure-specific, generalities across energy sectors are apparent. For example, largebodied species with high wing loading and relatively low maneuverability appear to be especially susceptible to direct effects of tall structures, and the risk of collision is likely greater when structures are placed perpendicular to flight paths or in areas of high use. Given that all infrastructure types result in direct loss or fragmentation of habitat and may affect the distribution of predators, indirect effects mediated by these mechanisms may be pervasive across energy facilities. When considered together, the direct and indirect effects of renewable energy facilities, and the transmission lines serving these facilities, are likely cumulative. Ultimately, cross-facility and cross-taxon meta-analyses will be necessary to fully understand the cumulative impacts of energy infrastructure on birds. Siting these facilities in a way that minimizes avian impacts will require an expanded understanding of how birds perceive facilities and the mechanisms underlying direct and indirect effects. © 2016 Cooper Ornithological Society.

Dwyer J.F.,Virginia Polytechnic Institute and State University | Dwyer J.F.,EDM International Inc. | Fraser J.D.,Virginia Polytechnic Institute and State University | Morrison J.L.,Trinity College at Hartford
Condor | Year: 2012

Many birds do not breed in the year(s) immediately following independence from parental care. Instead, they spend time as immatures attaining adult plumage and spend time as floaters searching for an opportunity to breed. Floaters are nonbreeding adults. Survival during this period often is poorly understood because immatures and floaters can be secretive and range widely, making them difficult to track. From July 2006 through March 2009, we used radio-tracking data collected by aerial telemetry to estimate survival of 58 nonbreeding Crested Caracaras (Caracara cheriway). Based on an information-theoretic approach, the best-supported models indicated differences in monthly survival, which was lowest (0.953) during the peak of breeding (December-January), slightly higher (0.984) during the remainder of the breeding season (October, November, February, March), and highest (0.995) during the nonbreeding season (April-September). We identified life stage as juvenile, immature, or floater on the basis of plumage. We found no effect of sex or life stage on monthly or annual survival, and annual survival was intermediate (0.826) between existing estimates for breeding caracaras (0.876 for males and 0.906 for females) and the dependent juveniles (0.694) of breeding caracaras. None of the birds we tracked nested during our 33-month study. Our findings provide unique insight into reduced survival of nonbreeding individuals during the period when the remainder of the population breeds, and the long-term persistence of individual floaters supports the assertion of previous authors that all breeding habitat is occupied. © The Cooper Ornithological Society 2012.

Harness R.E.,EDM International Inc. | Juvvadi P.R.,Raptor Conservation Foundation | Dwyer J.F.,EDM International Inc.
Journal of Raptor Research | Year: 2013

Avian electrocutions are regularly documented worldwide. Electrocutions are thought to affect avian populations in Asia, but regional research has not been widely disseminated. In this study, we sought to identify whether power lines in rural India were involved in avian electrocutions and, if so, to identify at-risk species and problematic configurations, and to develop a predictive model. To collect data, we visited power poles to search for avian carcasses. We recorded six variables at each pole: line voltage, insulator configuration, conductor separation, jumper count, surrounding habitat, and presence of an avian carcass. We used multivariate logistic regression to model the probability that an avian carcass was found. We surveyed 15 line segments supported by 675 poles, and found 162 carcasses. We found carcasses of five raptor species, including Eurasian Kestrel (n = 5; Falco tinnunculus) and White-eyed Buzzard (n = 4; Butastur teesa), though passerine carcasses were more numerous. All modeled variables contributed to the probability of finding a carcass; however, only pin height and jumper count were important contributors to the averaged model. Specifically, carcasses were most common beneath poles supporting jumpers and beneath tangent poles with low center pins. This is similar to another recently completed electrocution model from California, U.S.A., where jumpers and grounding were key predictive variables. There is an ongoing effort to provide electric power to all rural areas in India. Unless poles are retrofitted to minimize electrocution risk, avian electrocutions are likely to increase as power delivery expands. With the simple model we provide, personnel with minimal training can report the results of surveys quantifying electrocution risk, and help utilities prioritize retrofitting dangerous poles. © 2013 The Raptor Research Foundation, Inc.

Dwyer J.F.,EDM International Inc. | Harness R.E.,EDM International Inc. | Donohue K.,Southern California Edison
Conservation Biology | Year: 2014

Electrocution on overhead power structures negatively affects avian populations in diverse ecosystems worldwide, contributes to the endangerment of raptor populations in Europe and Africa, and is a major driver of legal action against electric utilities in North America. We investigated factors associated with avian electrocutions so poles that are likely to electrocute a bird can be identified and retrofitted prior to causing avian mortality. We used historical data from southern California to identify patterns of avian electrocution by voltage, month, and year to identify species most often killed by electrocution in our study area and to develop a predictive model that compared poles where an avian electrocution was known to have occurred (electrocution poles) with poles where no known electrocution occurred (comparison poles). We chose variables that could be quantified by personnel with little training in ornithology or electric systems. Electrocutions were more common at distribution voltages (≤33 kV) and during breeding seasons and were more commonly reported after a retrofitting program began. Red-tailed Hawks (Buteo jamaicensis) (n = 265) and American Crows (Corvus brachyrhynchos) (n = 258) were the most commonly electrocuted species. In the predictive model, 4 of 14 candidate variables were required to distinguish electrocution poles from comparison poles: number of jumpers (short wires connecting energized equipment), number of primary conductors, presence of grounding, and presence of unforested unpaved areas as the dominant nearby land cover. When tested against a sample of poles not used to build the model, our model distributed poles relatively normally across electrocution-risk values and identified the average risk as higher for electrocution poles relative to comparison poles. Our model can be used to reduce avian electrocutions through proactive identification and targeting of high-risk poles for retrofitting. © 2013 Society for Conservation Biology.

EDM International Inc. | Date: 2012-02-07

machines for cleaning electrical conductors.

EDM International Inc. | Date: 2015-09-01

Disclosed is a method and system for the repair and reinforcement of poles.

EDM International Inc. | Date: 2012-04-12

Electrical conductivity monitor for monitoring conductor ampacity in overhead transmission lines.

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