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Fort Collins, CO, United States

Wild mallards (Anas platyrhychos) are considered one of the primary reservoir species for avian influenza viruses (AIV). Because AIV circulating in wild birds pose an indirect threat to agriculture and human health, understanding the ecology of AIV and developing risk assessments and surveillance systems for prevention of disease is critical. In this study, mallards were experimentally infected with an H4N6 subtype of AIV by oral inoculation or contact with an H4N6 contaminated water source. Cloacal swabs, oropharyngeal swabs, fecal samples, and water samples were collected daily and tested by real-time RT-PCR (RRT-PCR) for estimation of viral shedding. Fecal samples had significantly higher virus concentrations than oropharyngeal or cloacal swabs and 6 month old ducks shed significantly more viral RNA than 3 month old ducks regardless of sample type. Use of a water source contaminated by AIV infected mallards, was sufficient to transmit virus to naïve mallards, which shed AIV at higher or similar levels as orally-inoculated ducks. Bodies of water could serve as a transmission pathway for AIV in waterfowl. For AIV surveillance purposes, water samples and fecal samples appear to be excellent alternatives or additions to cloacal and oropharyngeal swabbing. Furthermore, duck age (even within hatch-year birds) may be important when interpreting viral shedding results from experimental infections or surveillance. Differential shedding among hatch-year mallards could affect prevalence estimates, modeling of AIV spread, and subsequent risk assessments. Source


Washburn B.E.,National Wildlife Research Center
Journal of Raptor Research | Year: 2014

Although often perceived as a species of remote settings, Ospreys (Pandion haliaetus) are highly adaptable and currently are abundant in many urban and suburban landscapes. Living in close proximity to humans, Ospreys often come into conflict with people and several important issues require the attention of and management by natural resource professionals. These include effects on: (1) industry (e.g., foraging at aquaculture facilities), (2) utilities (e.g., nesting on electric utility power poles and transmission towers), (3) communication networks (e.g., nesting on cellular towers), and (4) transportation systems (e.g., risks posed to human health and safety due to Osprey-aircraft collisions). Due to the Osprey's migratory and wintering habits, conflicts between Ospreys and humans are generally seasonal in nature (i.e., during the nesting season); Florida is an important exception. Creative mitigation measures (many currently being developed and evaluated) that combine effective management and monitoring will provide a better understanding of human-Osprey conflicts and ensure our successful coexistence with Osprey populations in the future. © 2014 The Raptor Research Foundation, Inc. Source


Washburn B.E.,National Wildlife Research Center
Landscape and Urban Planning | Year: 2012

Transfer stations are an important component of modern solid waste management systems. Solid waste management facilities (e.g., landfills) are very attractive to and used by many birds, resulting in a variety of health and safety problems, including disease transmission to humans and increased risk of wildlife-aircraft collisions. In the United States, the Federal Aviation Administration recommends municipal solid waste management facilities (e.g., landfills, transfer stations) not be sited within 8. km of an airport. Little information is available regarding the attractiveness of transfer stations to birds or the factors that might influence avian use, particularly on a national scale. The objectives of my study were to: (1) quantify avian use of transfer stations, (2) determine if building design features influence their attractiveness to birds, and (3) determine if other factors (e.g., season, geographic location, operational procedures) influence bird use. Twenty-nine waste transfer facilities and 4 control sites, located in 7 states (representative of various U.S. geographical regions) were studied. Avian abundance and activity was quantified at each facility and control site twice per week for one year. Nuisance bird species commonly observed using transfer stations (e.g., feeding on refuse) included gulls, European starlings, and crows. Patterns of wildlife use at transfer stations varied by season, geographic location, transfer station building design, and on-site management characteristics. Overall, this study demonstrates that wildlife use of transfer stations, particularly by nuisance birds, can be substantial. © 2011. Source


Smith P.A.,Carleton University | Smith P.A.,National Wildlife Research Center | Wilson S.,Smithsonian Institution
Oecologia | Year: 2010

Nest survival may vary throughout the breeding season for many bird species, and the nature of this temporal variation can reveal the links between birds, their predators, and other components of the ecosystem. We used program Mark to model patterns in nest survival within the breeding season for shorebirds nesting on arctic tundra. From 2000 to 2007, we monitored 521 nests of five shorebird species and found strong evidence for variation in nest survival within a nesting season. Daily nest survival was lowest in the mid-season in 5 of 8 years, but the timing and magnitude of the lows varied. We found no evidence that this quadratic time effect was driven by seasonal changes in weather or the abundance of predators. Contrary to our prediction, the risk of predation was not greatest when the number of active shorebird nests was highest. Although nest abundance reached a maximum near the middle of the breeding season, a daily index of shorebird nest activity was not supported as a predictor of nest survival in the models. Predators' access to other diet items, in addition to shorebird nests, may instead determine the temporal patterns of nest predation. Nest survival also displayed a positive, linear relationship with nest age; however, this effect was most pronounced among species with biparental incubation. Among biparental species, parents defended older nests with greater intensity. We did not detect a similar relationship among uniparental species, and conclude that the stronger relationship between nest age and both nest defence and nest survival for biparental species reflects that their nest defence is more effective. © 2010 Springer-Verlag. Source


Rhyan J.C.,National Wildlife Research Center
OIE Revue Scientifique et Technique | Year: 2013

Natural infections by Brucella spp. have been observed in wild populations. Owing to the similarity of lesions and the course of disease across host and pathogen species, the pathogenesis of brucellosis in wildlife is considered similar to that in domestic animals, which has been studied extensively. Similarities include tropism for reproductive and mammary tissues, trophoblast colonisation by the organism, and similar histopathological findings in organs, especially in the reproductive tract. Differences in the disease course exist and are likely to be attributable to immunological and behavioural differences among species. Further study of the pathogenesis and pathobiology of brucellosis in wildlife is expected to yield unique knowledge with application to disease management in both wild and domestic species. Source

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