Progress 09/01/15 to 08/31/20
Outputs
Target Audience:The goal of the A-BIRDs project is to determine the costs and benefits of wild birds on organic farms, as well as to develop tools to aid growers in managing wild birds. Our target audience is organic vegetable growers who rely on natural enemies (including birds) for pest suppression, but must also minimize the food safety risk presented by wildlife incursion. The broad datasets from this project are now providing important insights into 1) the influence of farm-management practices on wild bird diversity, which will be invaluable to growers throughout the western United States, 2) the impacts of birds on crop pest suppression, and 3) the risk presented by birds as reservoirs of human and livestock pathogens. These data are the first to assess community-level costs and benefits of birds across a wide geographical area, and are proving critical for informing ongoing development of food-safety measures and regulations. Changes/Problems:
Nothing Reported
What opportunities for training and professional development has the project provided?This project supported the training of one Ph.D. student. Dr. Olivia M. Smith completed her dissertation project based on this work and successfully graduated in May 2020. In addition, the project supported research training and experience for 5 undergraduate students in a variety of capacities that included field work (e.g. bird capture and sample collection) as well as laboratory work (e.g. DNA extraction and PCR). Professional development was supported for one postdoctoral researcher. Dr. Chris Latimer was involved with the project through the mentorship of co-PI Dr. Christina Kennedy. Dr. Latimer developed analytical skills during the process of data analysis and was involved with manuscript writing and preparation. How have the results been disseminated to communities of interest?Research results have been communicated to peer scientists through publication of 8 peer-reviewed papers and 5 presentations at scientific conferences (e.g. American Ornithological Society). Our results and the relevant changes in knowledge have also been communicated to farmers and the public through on-farm extension talks. We have also published 8 articles accessible through the public and stakeholders through online platforms (e.g. eOrganic). What do you plan to do during the next reporting period to accomplish the goals?
Nothing Reported
Impacts
What was accomplished under these goals?
Goal 1: Relate wild-bird biodiversity to farm-management practices, through intensive field sampling and GIS modeling. 1) Major activities completed / experiments conducted - Visits to 52 farms across 3 years in California, Oregon and Washington States, to collect information about wild bird diversity and abundance, landscape (habitat) attributes, farm attributes, farm management practices. 2) Data collected - Bird diversity and abundance estimates (point counts and live-captures). 3) Summary statistics and discussion of results - We observed 134 species and found that 20% of the species observed represented 81% of the of total observations. The commonly observed birds represented a combination of native (e.g. American Robin) and non-native (e.g. European Starling) species. We found that landscape and farm attributes both had effects on the bird communities observed on the farm. The amount of natural habitat surrounding a farm increased the density of native species and reduced the density of non-native species. Inclusion of livestock on the farm (i.e. crop-livestock integration) positively affected native species density and diversity. However, inclusion of livestock on the farm also had strong positive effects on non-native species density. We found no evidence for a negative effect of non-native bird species on the abundance or richness of native species. Relative to crop-only farms, on average, crop-livestock systems exhibited 1.5 times higher patch richness, 2.4 times higher density of farm structures, 7.3 times smaller field sizes, 2.4 times greater integration of woody crops, and 5.3 times greater integration of pasture/hay habitat on farm. These interacting factors appeared to affect the bird community. Collectively, our findings suggest that farms that integrate livestock and crop production can attract robust native bird communities, especially within landscapes devoted to intensified food production. 4) Key outcomes - These results reflect a change in knowledge that has been communicated to stakeholders via a combination of peer-reviewed scientific papers, publications accessible to a "lay-audience" (e.g. online articles through The Nature Conservancy), and direct meetings (extension talks) with growers. Specifically, these studies reveal that small-scale, diversified farms are able to improve the abundance and diversity of bird species. This reflects a potentially positive mechanistic relationship between agricultural practices and bird conservation. Goal 2: Quantify the birds' benefits for pest-insect control through non-invasive, molecular analysis of prey-DNA remains in bird feces. 1) Major activities completed / experiments conducted - We collected 1200 wild bird fecal samples during visits to 52 farms in California, Oregon and Washington States spanning a 2-year period (2016-2017). We extracted DNA from those fecal samples and used gene sequencing comparisons to determine taxonomic identities of prey items that had been consumed by the birds. 2) Data collected - DNA sequence data and taxonomic identifiers. 3) Summary statistics and discussion of results - The analysis revealed at least 103 arthropod species known to be crop pests, which indicates that wild birds do predate insect pests of crops. From the 4 most common bird species, the diet items spanned 30 orders of insects, which varied in their relative abundance in bird diets between years and among early and late growing seasons. This suggests possible differences in the functional role of birds may vary across the growing season and be highly context dependent. We are currently exploring patterns such as farm management and landscape context that may explain this variation in bird diets and developing new quantitative approaches that will help elucidate the functional role of birds on farms across space and time. 4) Key outcomes - These results reflect a change in knowledge with respect to our understanding of how wild birds may affect arthropod pests of crops. At this time, we are still in the process of analysis and manuscript preparation. However, analyses so far suggest that wild birds can have a positive effect on biocontrol of insect pests of crops. This strengthens the argument that wild birds provide a valuable ecosystem "service" to farmers. Goal 3: Assess the birds' risk of spreading pathogens and parasites that endanger food safety and human/livestock health. 1) Major activities completed / experiments conducted - Visits to 52 farms across 3 years in California, Oregon and Washington States, to collect bird fecal samples from the farm environment (e.g. field crops and processing areas). Fecal samples were screened for presence of Campylobacter spp., Salmonella spp., and Escherichia coli bacteria. The fecal pathogen data were then analyzed relative to estimates of wild bird diversity and abundance, landscape (habitat) attributes, farm attributes, and farm management practices. 2) Data collected - We collected 2,024 fecal samples from captured birds alongside 1,215 fecal samples from brassica fields and food processing areas. 3) Summary statistics and discussion of results - Campylobacter spp. were detected in 10.2% of feces from captured birds and 13.1% of feces from production areas. Non-native birds were 4.1 times more likely to have Campylobacter spp. than native birds. Salmonella spp. were detected in 0.2% of feces from production areas and were never detected in captured birds. We detected evidence of Shiga toxigenic E. coli in one sample across the >3,200 tested. Campylobacter spp. prevalence in feces from production areas increased with increasing mammalian livestock densities in the landscape but decreased with in-creasing amounts of natural habitat. Our findings suggest that natural habitat around farms may reduce crop contamination rates by birds. This is perhaps because natural habitat can promote native birds that are less likely to harbor foodborne pathogens or because it decreases contact with livestock waste. Our results suggest that preservation of natural habitats around farms could benefit both conservation and food safety, contrary to current standards for 'best practices'. 4) Key outcomes - These results reflect a change in knowledge that has been communicated to stakeholders via a combination of peer-reviewed scientific papers, publications accessible to a "lay-audience" (e.g. online articles through The Nature Conservancy), and direct meetings (extension talks) with growers. Specifically, these studies reveal that wild birds do introduce pathogenic bacteria into the farm environment, where they could enter the human food system and cause food-borne illness. However, not all wild bird species represent the same level of risk and there is evidence that support of natural habitat around the farm can reduce this risk. As a result, there remains opportunities to support bird diversity on farms while also minimizing risks to food safety.
Publications
- Type:
Journal Articles
Status:
Published
Year Published:
2020
Citation:
Latimer, C.E., Smith, O.M., Taylor, J.M., Edworthy, A., Owen, J., Snyder, W.E., and Kennedy, C.M. 2020. Landscape context modifies the physiological stress response of birds to farm diversification. Journal of Applied Ecology 57: 671-680. doi.org/10.1111/1365-2664.13583
- Type:
Journal Articles
Status:
Published
Year Published:
2020
Citation:
Smith, O.M., Edworthy, A., Taylor, J.M., Jones, M., Tormanen, A., Kennedy, C.M., Fu, Z., Latimer, C.E., Cornell, K.A., Michelotti, L.A., Sato, C., Northfield, T., Snyder, W.E., and Owen, J.P. 2020. Agricultural intensification heightens food safety risks posed by wild birds. Journal of Applied Ecology (In press). doi: 10.1111/1365-2664.13723
- Type:
Journal Articles
Status:
Under Review
Year Published:
2020
Citation:
Smith, O.M., Taylor, J.M., Echeverri, A., Northfield, T., Cornell, K.A., Jones, M.S., Latimer, C.E., Owen, J.P., Snyder, W.E., and Kennedy, C.M. Big wheel keep on turnin: linking grower attitudes, farm management, and delivery of avian ecosystem services. (In review).
- Type:
Journal Articles
Status:
Published
Year Published:
2020
Citation:
Smith, O.M., Snyder, W.E., and Owen, J.P. 2020. Are we overestimating risk of spillover of enteric pathogens from wild birds to humans? Biological Reviews 95: 652-679. doi: 10.1111/brv.12581
- Type:
Journal Articles
Status:
Published
Year Published:
2020
Citation:
Smith, O.M., Kennedy, C.M., Owen, J.P., Northfield, T.D., Latimer, C.E., and Snyder, W.E. 2020. Highly diversified crop-livestock farming systems reshape wild bird communities. Ecological Applications 30: e02031. doi: 10.1002/eap.2031
- Type:
Other
Status:
Published
Year Published:
2020
Citation:
Smith, O.M., Bourbour, R., Cornell, K.A., Groendyk, S., Hannay, M., Martinico, B., Utley, O., Snyder, W.E., and Lindell, C. Promoting beneficial raptors: identification, pest control services, and management. eXtension/eOrganic publication 34052. http://eorganic.org/node/34052
- Type:
Other
Status:
Published
Year Published:
2020
Citation:
Smith, O.M. and Kennedy, C.K. 2020. What is the best type of farm for birding? Cool Green Science Blog, The Nature Conservancy. https://blog.nature.org/science/2020/05/18/what-is-the-best-type-of-farm-for-birding/?fbclid=IwAR21zsxA8dzBrGEGtrb6dfur4TrcQAkBp2-qgwz4o7JDOZvROUTFK66WzUk
- Type:
Other
Status:
Published
Year Published:
2020
Citation:
Latimer, C.E. and Kennedy, C.K https://blog.nature.org/science/2020/03/02/new-research-shows-healthy-agriculture-means-healthier-birds/
|
Progress 09/01/18 to 08/31/19
Outputs
Target Audience:The goal of the A-BIRDs project is to determine the costs and benefits of wild birds on organic farms, as well as to develop tools to aid growers in managing wild birds. Our target audience is organic vegetable growers who rely on natural enemies (including birds) for pest suppression, but must also minimize the food safety risk presented by wildlife incursion. Through the 2016-2017 field seasons we surveyed 55 farms across California, Oregon, and Washington, which varied in natural vegetation cover, bird community composition, and livestock density. We also captured a representative sample of wild birds at each farm and collected samples to test for human and livestock pathogens vectored by birds. In the 2018 field season we conducted a manipulative experiment across 13 working farms, where we both excluded and allowed birds to forage on paired broccoli plants and tracked densities of pest and beneficial insects. These broad datasets are now providing important insights into 1) the influence of farm-management practices on wild bird diversity, which will be invaluable to growers throughout the western United States, 2) the impacts of birds on crop pest suppression, and 3) the risk presented by birds as reservoirs of human and livestock pathogens. These data are the first to assess community-level costs and benefits of birds across a wide geographical area, and are proving critical for informing ongoing development of food-safety measures and regulations. Changes/Problems:
Nothing Reported
What opportunities for training and professional development has the project provided?Two graduate students (Olivia Smith and Joseph Taylor), as well as 9 undergraduate research assistants are currently being trained or were trained on this project. Olivia Smith is characterizing avian communities in relation to landscape features and farm management strategies. Joseph Taylor is examining the role of wild bird communities in suppressing pest insects, and will be trained in the bioinformatics and analysis of sequencing data for DNA diet analysis. He will also further develop his stable isotope skills in processing and analyzing the feather samples collected in this project. How have the results been disseminated to communities of interest? Smith, OM, WE Snyder and JP Owen. In revision. Understanding food safety risks associated with wild birds: a meta-analysis and conceptual framework. Biological Reviews. Latimer, CE, O Smith, J Taylor, AB Edworthy, J Owen, WE Snyder and CM Kennedy. In review. Landscape context mediates the physiological stress response of birds to farm diversification. Journal of Applied Ecology. Smith, OM, CM Kennedy, JP Owen, CE Latimer, and WE Snyder. 2019. Highly diversified crop-livestock farming systems reshape wild bird communities. Ecological Applications, in press. What do you plan to do during the next reporting period to accomplish the goals? Christopher Latimer is analyzing large-scale citizen-science datasets (eBird and Breeding Bird Survey) to understand how bird communities, and therefore, potential services (pest control) and disservices (crop damage and disease) have changed in space and time as a result of concurrent changes to agricultural intensification. Additionally, Chris is using these extensive datasets to explore how changes in weather and climate might interact with gradients in agricultural intensification to further impact the spatial and temporal patterning of avian biodiversity. Lastly, Chris will synthesize information from the scientific literature and currently developed tools (Cool Farm Tool) to make recommendations on how to update the current implementation of Habitat Network to make it more relevant and user-friendly for organic farmers. We are working with the Cornell Lab of Ornithology to further develop Habitat Network, an online tool where growers can gain valuable information on managing their farm for birds using habitat manipulations. In addition to relying on our research, we are also collaborating with developers of The Cool Farm Tool (https://coolfarmtool.org/coolfarmtool/) to utilize their systematic literature syntheses and expert assessments on the impacts of agriculture on biodiversity to inform the features to add to Habitat Network to tailor to growers. We also now have completed development of a web-enabled version of Cornell's Merlin App, which helps growers identify beneficial and detrimental bird species, and cab used through smart phones.
Impacts
What was accomplished under these goals?
Altogether, over two years of field work, we surveyed birds on 52 farms that grew primarily mixed vegetables and fruits alone or integrated livestock into production. Farm landscapes were ground-truthed using aerial images, digitized in ArcGIS version 10.3, and analyzed using FRAGSTATS software. Surrounding landscapes were classified using NLCD, CDL, and the gridded "livestock of the world" data layers. We then used these data to build structural equation models (SEMs) that interrelated farming system, farm management practices, and resulting populations of native and invasive birds. We found that crop-livestock systems harbored higher native bird density and richness relative to crop only farms, a benefit more pronounced on farms embedded in non-natural landscapes. Crop-livestock systems bolstered native insectivores linked to the suppression of agricultural pest insects but did not bolster native granivores nor omnivores that may damage crops. Crop-livestock systems also significantly increased density of non-native birds, primarily European starlings (Sturnus vulgaris) and house sparrows (Passer domesticus) that may compete with native birds for resources. Models supported a small, positive correlation between non-native density and overall native bird density as well as between non-native density and native granivore density. Relative to crop-only farms, crop-livestock systems exhibited higher patch richness and density of farm structures, reduced field sizes, and greater integration of woody crops and pasture/hay habitat on farm. Wild birds may have responded to this habitat diversity and/or associated food resources. Individual farm factors had significantly lower predictive power than farming system alone, suggesting crop-livestock systems may impact wild birds through a suite of factors that change with system conversion. Collectively, our findings suggest that farms that integrate livestock and crop production can attract robust native bird communities, especially within landscapes devoted to intensified food production. These data have now been published in Ecological Applications, and related outreach materials are published in eOrganic Dr. Christopher Latimer, a post-doctoral researcher that is supervised by Dr. Christina Kennedy at The Nature Conservancy, used bird-condition measurements collected during our mist netting efforts to link farming practices, and the structure of landscapes within which farms are situated, on wild bird condition. Across 38 organic, mixed-produce farms spanning the U.S. west coast, we quantified three physiological biomarkers that are widely used to capture variation in short and long-term stress responses for nine bird species with diverse life-history traits. We used multilevel models to examine relationships between bird stress responses, farm management and landscape context, while controlling for other potentially confounding variables. Increasing compositional heterogeneity on farms had stronger effects on bird condition relative to other diversification practices. In general, birds had lower stress responses on more diverse farms and in more complex landscapes with high amounts of seminatural cover. However, interactions between farm diversity and landscape context suggested that benefits were greatest in more-simplified landscapes with low proportions of seminatural cover. In contrast, birds appeared to be more stressed and in poorer condition on more diverse farms embedded within complex landscapes. We found no differences between stress response and the degree of human association, suggesting that species responded similarly to farm management and landscape context. Stress responses often develop as a precursor to population declines and can provide insights into mechanisms affecting population persistence in agroecosystems. Our results demonstrate that landscape context plays a significant role in modulating physiological stress responses of birds to farm management. Objective 3: Assess the birds' risk of spreading pathogens and parasites that endanger food safety and human/livestock health. Land usage and farm management may increase likelihood of spillover by increasing exposure of wild birds to pathogens and by altering fecal contamination rates with production. Therefore, we tested 1217 fecal samples collected from fields and 2048 fecal samples collected from mist netted birds for Campylobacter spp., E. coli, and Salmonella spp. on 51 brassica production farms along the U.S. West Coast that grew crops alone or integrated livestock into production. We found an overall prevalence of 13.1%, 0%, and 0.2% in fecal samples collected in production areas and an overall prevalence of 10.1%, 0.05%, and 0% infecal samples collected directly from wild birds for Campylobacter spp., E. coli, and Salmonella spp., respectively. For every 1% decrease in natural habitat, the odds of recovering Campylobacter spp. in feces collected from production areas increased by 1.1%, while the odds of recovering Campylobacter spp. increased by 3.3% with every 1 unit increase in mammalian livestock density in the landscape (livestock/km2). Collectively, our findings suggest natural habitat could decrease food safety risks while produce production near mammalian livestock may increase food safety risks.
Publications
- Type:
Journal Articles
Status:
Submitted
Year Published:
2019
Citation:
Smith, OM, WE Snyder and JP Owen. In revision. Understanding food safety risks associated with wild birds: a meta-analysis and conceptual framework. Biological Reviews.
- Type:
Journal Articles
Status:
Submitted
Year Published:
2019
Citation:
Latimer, CE, O Smith, J Taylor, AB Edworthy, J Owen, WE Snyder and CM Kennedy. In review. Landscape context mediates the physiological stress response of birds to farm diversification. Journal of Applied Ecology.
- Type:
Journal Articles
Status:
Accepted
Year Published:
2019
Citation:
Smith, OM, CM Kennedy, JP Owen, CE Latimer, and WE Snyder. 2019. Highly diversified crop-livestock farming systems reshape wild bird communities. Ecological Applications, in press.
- Type:
Conference Papers and Presentations
Status:
Accepted
Year Published:
2019
Citation:
Co-PD Kennedy worked with Olivia Smith and Chris Latimer to co-develop a symposium on the net effects of birds in in agroecosystems with leading researchers in the field. This symposium was part of the program of the American Ornithological Society conference in June 2019.
|
Progress 09/01/17 to 08/31/18
Outputs
Target Audience:The goal of the A-BIRDs project is to determine the costs and benefits of wild birds on organic farms, as well as to develop tools to aid growers in managing wild birds. Our target audience is organic vegetable growers who rely on natural enemies (including birds) for pest suppression, but must also minimize the food safety risk presented by wildlife incursion. Through the 2016-2017 field seasons we surveyed 55 farms across California, Oregon, and Washington, which varied in natural vegetation cover, bird community composition, and livestock density. We also captured a representative sample of wild birds at each farm and collected samples to test for human and livestock pathogens vectored by birds. In the 2018 field season we conducted a manipulative experiment across 13 working farms, where we both excluded and allowed birds to forage on paired broccoli plants and tracked densities of pest and beneficial insects. These broad datasets are now providing important insights into 1) the influence of farm-management practices on wild bird diversity, which will be invaluable to growers throughout the western United States, 2) the impacts of birds on crop pest suppression, and 3) the risk presented by birds as reservoirs of human and livestock pathogens. These data are the first to assess community-level costs and benefits of birds across a wide geographical area, and are proving critical for informing ongoing development of food-safety measures and regulations. Changes/Problems:
Nothing Reported
What opportunities for training and professional development has the project provided?Two graduate students (Olivia Smith and Joseph Taylor), as well as 9 undergraduate research assistants are currently being trained or were trained on this project. Olivia Smith is characterizing avian communities in relation to landscape features and farm management strategies. Joseph Taylor is examining the role of wild bird communities in suppressing pest insects, and will be trained in the bioinformatics and analysis of sequencing data for DNA diet analysis. He will also further develop his stable isotope skills in processing and analyzing the feather samples collected in this project. How have the results been disseminated to communities of interest?We have engaged grower-collaborators on this project and have had on-farm discussions with most growers to gauge their concerns associated with wild birds. At the end of each sampling round, we shared preliminary findings on the resident bird communities at each farm. We are working with the Cornell Lab of Ornithology to further develop Habitat Network, an online tool where growers can gain valuable information on managing their farm for birds using habitat manipulations. In addition to relying on our research, we are also collaborating with developers of The Cool Farm Tool (https://coolfarmtool.org/coolfarmtool/) to utilize their systematic literature syntheses and expert assessments on the impacts of agriculture on biodiversity to inform the features to add to Habitat Network to tailor to growers. We also now have completed development of a web-enabled version of Cornell's Merlin App, which helps growers identify beneficial and detrimental bird species, and cab used through smart phones. Co-PD Kennedy is working with Olivia Smith and Chris Latimer to co-develop a symposium on the net effects of birds in in agroecosystems with leading researchers in the field for the American Ornithological Society conference in June 2019. Several research talks have also been given: Academic presentations: Smith, O.M., J.M. Taylor, and W.E. Snyder. "Impact of natural habitat on trophic cascade strength in a broccoli system." 2018 ESA, ESC, and ESBC Joint Annual Meeting, Vancouver, BC, Canada. November 2018. Smith, O.M. "Landscape drivers of avian-mediated services and disservices in organic agriculture." PhD Proposal Defense, Washington State University, Pullman, WA. March 2018. We published three extension articles and completed one webinar in 2018: Chu, M., Crain, R., Dicks, L. Kennedy, C., Smith, O.M., Snyder, W. "Tools for Farm Biodiversity." eOrganic eXtension Webinar. February 2018. https://www.youtube.com/watch?v=vPxuQWmOZ1Q (Organized by O. Smith) Smith, OM and WE Snyder. 2018. Identifying bird nests on farm structures. eOrganic 74686. http://articles.extension.org/pages/74686/identifying-bird-nests-on-farm-structures DeVetter, L, B Gerdeman, M Arrington, H Spitler, WE Snyder, and OM Smith. 2018. How border vegetation impacts pollination and insect and bird species abundance on Washington blueberry farms. Whatcom Ag Monthly 7(4): http://extension.wsu.edu/wam/ Smith, OM, M Chu, RL Crain, LV Dicks, CM Kennedy and WE Snyder. 2018. Tools for farm biodiversity. eOrganic webinar. https://www.youtube.com/watch?v=vPxuQWmOZ1Q. What do you plan to do during the next reporting period to accomplish the goals?Objective 1) Olivia Smith has finished assessing how local and landscape variables affect bird communities on our cooperating farms and a manuscript describing this work will be submitted in early 2019. Christopher Latimer is analyzing large-scale citizen-science datasets (eBird and Breeding Bird Survey) to understand how bird communities, and therefore, potential services (pest control) and disservices (crop damage and disease) have changed in space and time as a result of concurrent changes to agricultural intensification. Additionally, Chris is using these extensive datasets to explore how changes in weather and climate might interact with gradients in agricultural intensification to further impact the spatial and temporal patterning of avian biodiversity. Lastly, Chris will synthesize information from the scientific literature and currently developed tools (Cool Farm Tool) to make recommendations on how to update the current implementation of Habitat Network to make it more relevant and user-friendly for organic farmers. Objective 2) As noted above, DNA has been extracted from all bird fecal samples and these have been sent to co-PD Rankin for diet sequencing. All diet sequencing will be completed during spring 2019. Rankin has established diet-item-identification pipelines that are speeding analysis of diet items. Objective 3) The project recently added a new lab manager, Lucas Michelotti, with extensive molecular-biology experience. Lucas is speeding our ability to test fecal samples for human pathogenic E. coli, Salmonella, and Campylobacter. Analyses will examine the bird, farm, and landscape factors influencing the prevalence of pathogens in these samples, and the risk of crop/livestock contamination.
Impacts
What was accomplished under these goals?
Objective 1: Relate biodiversity of wild birds to farm-management practices, through intensive field sampling and GIS modeling. Across two years (2016 and 2017), PhD student Olivia Smith conducted two sets of intensive whole farm point count surveys on a total of 52 organic farms in California, Oregon, and Washington. These farms spanned two Bird Conservation Regions (Coastal California and Northern Pacific Rainforest), and ranged in size from 0.38 ha to 272 ha. Farms were chosen that grow only fresh produce (2016: n = 19, 2017: n = 23) or that integrate livestock into their produce-production operations (2016: n = 21, 2017: n = 29). Farm landscapes were ground-truthed using aerial images, digitized in ArcGIS version 10.3, and analyzed using FRAGSTATS software. Surrounding landscapes were classified using NLCD, CDL, and the gridded "livestock of the world" data layers. Using these data we have built structural equation models (SEMs) that are interrelating farming system, farm management practices, and resulting populations of native and invasive birds. Our SEMs revealed that integrated livestock farms attracted more robust populations of native, insectivorous birds that presumably benefit natural pest control, but also more robust populations of invasive birds thought to be primary reservoirs of foodborne pathogens. A manuscript describing these findings will be submitted to a journal early in 2019; we also will develop outreach materials that will be submitted to eOrganic. In the winter of 2017-2018 we also completed a comprehensive grower survey that gathered additional data on farm management and growers' attitudes towards wild bird conservation and managing pest birds. We are now tabulating the responses with the goal to examine how growers' perceptions about birds, and bird benefits for pest management versus risks to food safety, align with our measurements of bird predation patterns and human pathogen prevalence on each farm. Dr. Christopher Latimer, a post-doctoral researcher that is supervised by Dr. Christina Kennedy at The Nature Conservancy, is using bird-condition measurements collected during our mist netting efforts to link farming practices, and the structure of landscapes within which farms are situated, on wild bird condition. This work has revealed that a large suite of human-associated bird species, such as American Robin, benefit from being on human-dominated farms. In contrast, many forest-associated native birds exhibit poorer condition when farm habitats dominate the landscape. The next step in this work is to link the presence in birds of potential foodborne human pathogens in bird feces collected during mist netting, with bird condition - this will allow us to delineate links between avian and human health. As described below, the pathogen testing is expected to be completed by February 2019. Objective 2: Quantify the birds' impact on pest insects through non-invasive, molecular analysis of prey-DNA remains in bird feces. During the 2016 and 2017 field seasons, PhD student Joseph Taylor and postdoc Amanda Edworthy conducted two sampling rounds at 45 farms. At each farm they installed 6 mist nets and trapped birds throughout the day. From this we collected over 2500 fecal samples from 65 species. The most frequently capture species were white-crowned sparrow (309), song sparrow (286), American goldfinch (267), American robin (281), savannah sparrow (143), house sparrow (143), house finch (139), and European starling (98). DNA from all fecal samples has now been extracted by Snyder's laboratory group, before being sent to co-PI Erin Rankin at UC Riverside for diet sequencing. The first 670 fecal samples have now been sequenced for both animal and plant prey, and the diet sequences have been assigned to the narrowest possible taxonomic level (generally genus but sometimes species). The remaining samples are being prepared for sequencing, and we expect this sequencing to be completed by March 2019. Next we will analyze the diet data with manuscripts describing the results to be prepared in summer 2019. In general, the first group of fecal samples that have been sequenced have revealed hundreds of arthropod and plant taxa in the diets of the large number of bird species from who we collected feces (described above). Analyzing these data is going to be logistical challenge, but will give remarkably detailed insight into what birds are eating on these farms and whether any arthropod prey are pests or beneficial species. Objective 3: Assess the birds' risk of spreading pathogens and parasites that endanger food safety and human/livestock health. In addition to fecal samples, we also collected tracheal swabs (to test for pathogens such as avian influenza and West Nile virus), blood smears (for blood parasites), serum (for antibodies indicating past infections), and ectoparasites, including ticks and fowl mites. We screened 750 blood smears from the 2016 field season, and found 9.5% prevalence of hemoproteous blood parasites. A major effort is currently underway to use fecal-extracted DNA and PCR, to screen for pathogenic strains of E. coli, Salmonella, and Campylobacter spp. As a side effort while visiting farms to survey bird communities, we collected bird feces from on broccoli foliage, the ground underneath broccoli plants, and around produce processing areas nearby to fields. We collected over 1400 of these "surface deposited" bird feces, and these have been tested for the presence of five virulence genes associated with pathogenic E. coli strains and Salmonella. Incidence of both pathogens was low, with a total of 13 detections of pathogenic E. coli and 4 detections of Salmonella. This suggests that feces of wild birds relatively rarely contaminate produce with these foodborne pathogens; however, the risk is not zero. We are beginning to test the surface-collected feces for five Campylobacter spp., and the mist-netted collected fecal samples for all three pathogens. When this dataset is complete we will have the most-complete snapshot for the incidence of potential foodborne pathogens for wild birds captured across a land use intensity gradient on farms in the United States.
Publications
- Type:
Journal Articles
Status:
Accepted
Year Published:
2019
Citation:
Jones, MS, TE Besser, LA Carpenter-Boggs, JP Reganold, JL Tylianakis and WE Snyder. 2019. Organic farming promotes biotic resistance to foodborne human pathogens. Journal of Applied Ecology, in press.
- Type:
Book Chapters
Status:
Published
Year Published:
2018
Citation:
Jones, MS and WE Snyder. 2018. Beneficial insect biodiversity in agriculture. In: Insect Biodiversity: Current Trends and Future Prospects (Eds. P Adler and R Foottit). Wiley Blackwell.
- Type:
Websites
Status:
Published
Year Published:
2018
Citation:
Smith, OM and WE Snyder. 2018. Identifying bird nests on farm structures. eOrganic 74686. http://articles.extension.org/pages/74686/identifying-bird-nests-on-farm-structures
- Type:
Websites
Status:
Published
Year Published:
2018
Citation:
DeVetter, L, B Gerdeman, M Arrington, H Spitler, WE Snyder, and OM Smith. 2018. How border vegetation impacts pollination and insect and bird species abundance on Washington blueberry farms. Whatcom Ag Monthly 7(4): http://extension.wsu.edu/wam/
- Type:
Websites
Status:
Published
Year Published:
2018
Citation:
Smith, OM, M Chu, RL Crain, LV Dicks, CM Kennedy and WE Snyder. 2018. Tools for farm biodiversity. eOrganic webinar. https://www.youtube.com/watch?v=vPxuQWmOZ1Q.
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Progress 09/01/16 to 08/31/17
Outputs
Target Audience:The goal of the A-BIRDs project is to determine the costs and benefits of wild birds on organic farms, as well as to develop tools to aid growers in managing wild birds. Our target audience is organic vegetable growers who rely on natural enemies (including birds) for pest suppression, but must also minimize the food safety risk presented by wildlife incursion. We selected 45 farms across California, Oregon, and Washington, which varied in natural vegetation cover, bird community composition, and livestock density. During July-September, 2016 and 2017, we conducted four rounds of field sampling, quantifying bird communities, vegetation cover, farm management strategies, and livestock abundance. We also captured a representative sample of wild birds at each farm and collected samples to test for human and livestock pathogens vectored by birds. This broad dataset will provide important insights into 1) the influence of farm-management practices on wild bird diversity, which will be invaluable to growers throughout the western United States, 2) the impacts of birds on crop pest suppression, and 3) the risk presented by birds as vectors of human and livestock pathogens. These data will be the first to assess community-level costs and benefits of birds across a wide geographical area, and will be critical for informing ongoing development of food-safety measures and regulations. Changes/Problems:
Nothing Reported
What opportunities for training and professional development has the project provided?Two graduate students (Olivia Smith and Joseph Taylor), as well as 4 undergraduate research assistants are currently being trained or were trained on this project. Olivia Smith is characterizing avian communities in relation to landscape features and farm management strategies. In spring 2017, she participated in an occupancy modelling workshop to develop statistical skills in modelling bird presence/absence and presented her research at a professional conference (American Ornithological Society) and in several interactive grower workshops. Joseph Taylor is examining the role of wild bird communities in suppressing pest insects, and will be trained in the bioinformatics and analysis of sequencing data for DNA diet analysis. He will also further develop his stable isotope skills in processing and analyzing the feather samples collected in this project. Aaron Tormamen was introduced to ecological fieldwork and insect trapping in 2016, and was trained in the lab to identify mosquitos prior to beginning a master's degree at Auburn University in January 2017. How have the results been disseminated to communities of interest?We have engaged grower-collaborators on this project, and have had on-farm discussions with most growers to gauge their concerns associated with wild birds. At the end of each sampling round, we shared preliminary findings on the resident bird communities at each farm. Several research talks have also been given: "Integrated Biological Pest Management Practices for Oregon Farms", August 23-24, 2016, Persephone Farm, Lebanon, OR (Joseph Taylor and Amanda Edworthy) "Creating Bird Habitat in Agriculture", October 7, 2016, Full Belly Farm, Guinda, CA (Olivia Smith) "Costs and Benefits of Birds in Agro-Ecosystems", February 17, 2017, Pasco TRAC, Pesticide Recertification Training, Pasco, WA (Olivia Smith) "Avian Community Structure on West Coast Organic Farms," July 28, 2017, American Ornithological Society, Lansing, MI (Olivia Smith) "Spotting Birds and Bugs on the Farm", October 8, 2017, Full Belly Farm, Guinda, CA (Olivia Smith and Joseph Taylor) We published three extensions articles on eOrganic in 2017. Smith, OS and WE Snyder. 2017. Identification, diet, and management of swallows and swifts common on organic farms. eXtension/eOrganic publication 21871 http://articles.extension.org/pages/74436/identification-diet-and-management-of-chickadees-and-warblers-common-on-organic-farms Smith, OS and WE Snyder. 2017. Identification, diet, and management of chickadees and warblers common on organic farms. eXtension/eOrganic publication 21859 http://articles.extension.org/pages/74435/identification-diet-and-management-of-swallows-and-swifts-common-on-organic-farms Smith, OS and WE Snyder. 2017. Western bluebird (Sialia mexicana) identification, diet, and management for organic farmers. eXtension/eOrganic publication 21870 http://articles.extension.org/pages/74434/western-bluebird-sialia-mexicana-identification-diet-and-management-for-organic-farmers What do you plan to do during the next reporting period to accomplish the goals?Objective 1) Olivia Smith will finalize analyses assessing how local and landscape variables affect occupancy of beneficial and harmful avian guilds and begin publishing in 2018. Christopher Latimer will utilize large-scale citizen-science datasets (eBird and Breeding Bird Survey) to understand how bird communities, and therefore, potential services (pest control) and disservices (crop damage and disease) have changed in space and time as a result of concurrent changes to agricultural intensification. Additionally, Chris will be using these extensive datasets to explore how changes in weather and climate might interact with gradients in agricultural intensification to further impact the spatial and temporal patterning of avian biodiversity. Lastly, Chris will synthesize information from the scientific literature and currently developed tools (Cool Farm Tool) to make recommendations on how to update the current implementation of Habitat Network to make it more relevant and user-friendly for organic farmers. Objective 2) Remaining DNA from the 2017 field season is currently being extracted and shipped for sequencing by February 2017. These samples will be sequenced and analyzed for prey items between Feb 2017 and August 2017. Erin Rankin will aid in training Snyder lab graduate students in analyzing and interpreting sequencing data to identify prey species. Stable isotope analysis of bird feathers is ongoing and will be completed this winter. Objective 3) Lab tests for potential foodborne pathogens, as well as zoonotic viruses, are ongoing, and sequencing runs to detect the major pathogens (e.g., E. coli, salmonella, West Nile virus) will be completed by April 2018. A Snyder lab postdoc with experience in DNA extraction and library preparation for sequencing will oversee lab activities, and will be aided by an undergraduate research assistant. Analyses will examine the bird, farm, and landscape factors influencing the prevalence of pathogens in bird communities, and the risk of crop/livestock contamination. Extension activities: We are collaborating with the Cornell Lab of Ornithology to develop Habitat Network, an online tool where growers can gain valuable information on managing their farm for birds using habitat manipulations. Olivia Smith is including the habitat variables of interest in Habitat Network in her landscape analyses to provide data-driven information on how the features of interest affect the avian community. We expect to have data for this valuable outreach tool by the 2018 reporting period. Additional extension products are being prepared, including eOrganic webinars and a web-enabled version of Cornell's Merlin App, which helps growers identify beneficial and detrimental bird species, which will be more-readily available through smart phones. Co-PD Kennedy is working with Olivia Smith, Chris Latimer, and Amanda Edworthy to co-develop a symposium on the net effects of birds in in agroecosystems with leading researchers in the field for an international conference in 2019. In addition, Olivia Smith, Chris Latimer, and Amanda Edworthy plan to submit an abstract and present at the American Ornithological Society Conference in 2018.
Impacts
What was accomplished under these goals?
Objective 1: Relate biodiversity of wild birds to farm-management practices, through intensive field sampling and GIS modeling. Across two years (2016 and 2017), PhD student Olivia Smith conducted two sets of intensive whole farm point count surveys on a total of 52 organic farms in California (2016: n = 12; 2017: n = 23), Oregon (2016: n = 14, 2017: n = 15), and Washington (2016: n =14, n =14) (Fig. 1). These farms were located between 35° 18' to 48° 27' N and -123° 27' to -120° 40' W, spanned two Bird Conservation Regions (Coastal California and Northern Pacific Rainforest), and ranged in size from 0.38 ha to 272 ha (2016: mean 29.95 ha ± 8.55 SE, 2017: mean 24.63 ha ± 6.35 SE). Farms were chosen that grow only fresh produce (2016: n = 19, 2017: n = 23) or that integrate livestock into their produce-production operations (2016: n = 21, 2017: n = 29). Farm landscapes were ground-truthed using aerial images, digitized in ArcGIS version 10.3, and analyzed using FRAGSTATS software. A comprehensive survey is currently underway to gather additional data on farm management. Surrounding landscapes were classified using NLCD, CDL, and the gridded "livestock of the world" data layers. Analyses are being conducted using hierarchical multi-species occupancy modeling. Dr. Christopher Latimer was hired as a post-doctoral researcher in mid-September, to be supervised by Dr. Christina Kennedy at The Nature Conservancy. Dr. Latimer will lead analyses linking large-scale species distribution modeling with field-level data and land cover data to synthesize relationships among wild birds, on-farm practices, landscape patterns, and food safety. Since starting, Dr. Latimer and Dr. Kennedy joined the WSU A-BIRDS field crew during the 2nd field season to observe/advise on data collection methods. They also traveled to Pullman, WA for a week-long grant planning meeting mid-October, 2017 with WSU PIs, students and post-doctoral researchers. Finally, they have assisted with data compilation, analyses, co-development of manuscripts examining the costs and benefits of conserving wild birds on organic farms. Dr. Latimer, in consultation with Dr. Kennedy, is currently compiling and analyzing datasets on bird species traits, catch rates, and farm and landscape attributes to select target bird species with sufficient data across landscape gradients of agricultural intensification and habitat fragmentation to examine how landscape context affects overall bird health and condition, and hence long-term persistence. This assessment will lead to a publication that will contribute to our understanding of the farm- and landscape-level features that limit the ability of birds to provide beneficial services (pest control) and disservices (crop damage and disease). Objective 2: Quantify the birds' impact on pest insects through non-invasive, molecular analysis of prey-DNA remains in bird feces. During the 2016 and 2017 field seasons, PhD student Joseph Taylor and postdoc Amanda Edworthy conducted two sampling rounds at 45 farms. At each farm we installed 6 mist nets and trapped birds throughout the day. We collected 2500 fecal samples from 65 species. The most frequently capture species were white-crowned sparrow (309), song sparrow (286), American goldfinch (267), American robin (281), savannah sparrow (143), house sparrow (143), house finch (139), and European starling (98). Fecal samples were stored in absolute ethanol at -80?C to preserve prey DNA. DNA from the 2016 samples was extracted over the winter and ~ half of these 900 samples have been sequenced to begin preliminary DNA diet analysis. DNA extraction and sequencing from the 2017 samples is ongoing. We also collected feathers which will be analyzed for stable isotopes, as a second method of assessing the trophic interactions of wild birds with local invertebrate communities. Joseph Taylor has expertise in stable isotope analysis and is currently processing these samples. Objective 3: Assess the birds' risk of spreading pathogens and parasites that endanger food safety and human/livestock health. In addition to fecal samples, we also collected tracheal swabs (to test for pathogens such as avian influenza and West Nile virus), blood smears (for blood parasites), serum (for antibodies indicating past infections), and ectoparasites, including ticks and fowl mites. We screened 750 blood smears from the 2016 field season, and found 9.5% prevalence of hemoproteous blood parasites. We will use DNA sequences from fecal samples (see above) to screen for pathogenic strains of E. coli, salmonella, listeria, and other human and livestock bacteria, viruses, and parasites. Lab-based assays will be done on these samples over the winter. This past year we confirmed that two invasive bird species are dominant members of the bird communities surrounding livestock-integrated organic farms--House finch (Passer domesticus) and European Starling (Sturnus vulgaris). These two species have been demonstrated to harbor and transmit the enteric pathogens Eschericia coli, Salmonella enterica and Campylobacter sp.. These field data confirm that bird species that are known to move food-borne pathogens are in high abundance on and around farms that produce both livestock and vegetables. Another key insight from 2017 was the determination that the majority of livestock-integrated farms participating in the project are raising cage-free, or pastured chickens. A separate group of 17 poultry farms (mixed cage-free and pastured) was sampled to determine the frequency of Campylobacter infections via collection and screening of poultry feces. All farms were positive for at least one Campylobacter sp., and the human pathogen C. jejuni was found on all farms. These data confirm that Campylobacter, which is the most common cause of food-borne illness, is extremely common in poultry flocks with access to outdoor environments. Thus, the coexistence and co-habitation of pest wild bird species and domestic poultry provides an opportunity to share and move human enteric pathogens onto crops. We collected samples during the spring and winter broccoli crops, which corresponded to breeding and migration periods for birds. This contrast will enable us to assess the seasonal differences in pathogen contamination risk on farms, and will also allow us to analyze bird species and individual characteristics influencing pathogen load in wild bird communities.
Publications
- Type:
Websites
Status:
Published
Year Published:
2017
Citation:
" Smith, OS and WE Snyder. 2017. Identification, diet, and management of swallows and swifts common on organic farms. eXtension/eOrganic publication 21871 http://articles.extension.org/pages/74436/identification-diet-and-management-of-chickadees-and-warblers-common-on-organic-farms
- Type:
Websites
Status:
Published
Year Published:
2017
Citation:
" Smith, OS and WE Snyder. 2017. Identification, diet, and management of chickadees and warblers common on organic farms. eXtension/eOrganic publication 21859 http://articles.extension.org/pages/74435/identification-diet-and-management-of-swallows-and-swifts-common-on-organic-farms
- Type:
Websites
Status:
Published
Year Published:
2017
Citation:
" Smith, OS and WE Snyder. 2017. Western bluebird (Sialia mexicana) identification, diet, and management for organic farmers. eXtension/eOrganic publication 21870 http://articles.extension.org/pages/74434/western-bluebird-sialia-mexicana-identification-diet-and-management-for-organic-farmers
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Progress 09/01/15 to 08/31/16
Outputs
Target Audience:The goal of the A-BIRDs project is to determine the costs and benefits of wild birds on organic farms, as well as to develop tools to aid growers in managing wild birds. Our target audience is organic vegetable growers who rely on natural enemies (including birds) for pest suppression, but must also minimize the food safety risk presented by wildlife incursion. We selected 45 farms across California, Oregon, and Washington, which varied in natural vegetation cover, bird community composition, and livestock density. During July-September, 2016, we conducted our first two rounds of field sampling, quantifying bird communities, vegetation cover, farm management strategies, and livestock abundance. We also captured a representative sample of wild birds at each farm and collected samples to test for human and livestock pathogens vectored by birds. This broad dataset will provide important insights into 1) the influence of farm-management practices on wild bird diversity, which will be invaluable to growers throughout the western United States, 2) the impacts of birds on crop pest suppression, and 3) the risk presented by birds as vectors human and livestock pathogens. These data will be the first to assess community-level costs and benefits of birds across a wide geographical area, and will be critical for informing ongoing development of food-safety measures and regulations. Changes/Problems:
Nothing Reported
What opportunities for training and professional development has the project provided?Two graduate students (Olivia Smith and Joseph Taylor), as well as one undergraduate research assistant (Aaron Tormamen) are currently being trained on this project. Olivia smith characterizing avian communities in relation to landscape features and farm management strategies. In spring 2016, she will participate in an occupancy modelling workshop to develop statistical skills in modelling bird presence/absence. Joseph Taylor is examining the role of wild bird communities in suppressing pest insects, and will be trained in the bioinformatics and analysis of sequencing data for DNA diet analysis. He will also further develop his stable isotope skills in processing and analyzing the feather samples collected in this project. Aaron Tormamen was introduced to ecological fieldwork and insect trapping this summer, and has been trained in the lab to analyze serum samples for antibody presence, as well as to identify mosquitoes which vector avian pathogens. Joseph Taylor recently presented his preliminary results at the International Entomological Congress (2016), and Olivia Smith will present her initial results to collaborators at The Nature Conservancy in Fort Collins in Spring 2017, providing them with important training as science communicators. How have the results been disseminated to communities of interest?We are collaborating with the Cornell Lab of Ornithology to develop Habitat Network, an online tool where growers can gain valuable information on managing their farm for birds using habitat manipulations. Olivia Smith is including the habitat variables of interest in Habitat Network in her landscape analyses to provide data driven information on how the features of interest affect the avian community. We expect to have data for this valuable outreach tool by the 2017 reporting period. Additional extension products are being prepared, including eOrganic webinars and a web-enabled version of Cornell's Merlin App, which helps growers identify beneficial and detrimental bird species, that will be more-readily available through smart phones. We have engaged grower-collaborators on this project, and have had on-farm discussions with most growers to gauge their concerns associated with wild birds. At the end of each sampling round, we shared preliminary findings on the resident bird communities at each farm. Several research talks have also been given: Olivia Smith ? Hosted workshop, "Identification and Management of Birds on Organic Farms," at Full Belly Farm in Guinda, CA. Full Belly is one of the largest farms in the study. Joseph Taylor and Amanda Edworthy ? Presentation for Integrated Pest and Biological Management workshop (Persephone Farm, August 2016) What do you plan to do during the next reporting period to accomplish the goals?Objective 1) Olivia Smith will finish correcting surveys for detection probability, characterize land-usage and characteristics around farms using a biologically relevant dispersal radius, characterize the community, analyze data, and prepare a manuscript with the first year's data. Her research has four main objectives: (1) Examine how local (farm) and landscape (surrounding land-usage up to biologically relevant radius based on community dispersal abilities or home range size) features affect avian richness, evenness, species diversity, functional diversity, and density in the early and late growing season; (2) Examine the relationship between richness and functional species diversity; (3) Examine how local and landscape features affect avian community structure across geographic regions (partition species by functional traits/guilds); and (4) Determine if the community assembles in a non-random order (shows nestedness). Objective 2) DNA will be extracted from fecal samples and sequenced between November 2016 and March 2017. Erin Rankin will aid in training Snyder lab graduate students in analyzing and interpreting sequencing data to identify prey species. Stable isotope analysis of bird feathers will also be conducted prior to the next field season. We expect to have preliminary results prepared by late 2017. Two to three additional field seasons will be conducted to increase sample size. Objective 3) Pathogen-related lab tests will be run between November 2016 and March 2017. A Snyder lab postdoc with experience in DNA extraction and library preparation for sequencing will oversee lab activities, and will be aided by an undergraduate research assistant. Preliminary analysis will examine the bird, farm, and landscape factors influencing the prevalence of pathogens in bird communities, and the risk of crop/livestock contamination. Two to three further field seasons will be conducted to increase sample size, and to gain an understanding of inter-annual variation in pathogen prevalence.
Impacts
What was accomplished under these goals?
Objective 1: Relate biodiversity of wild birds to farm-management practices, through intensive field sampling and GIS modeling. PhD student Olivia Smith conducted two sets of intensive whole farm point count surveys on 40 organic farms in 2016 in California (n = 12), Oregon (n = 14), and Washington (n = 14). Farms were chosen to encompass a wide range of sizes (.38 - 272.19 ha; mean = 29.95 ha ± 8.55 SE) and cropping schemes. Half of the farms had integrated livestock in addition to vegetables, and half were vegetables only. Farm landscapes were ground-truthed on aerial images, digitized in ArcGIS version 10.3, and analyzed using FRAGSTATS software by Olivia Smith. Surveys are currently being corrected for detection probability. Objective 2: Quantify the birds' impact on pest insects through non-invasive, molecular analysis of prey-DNA remains in bird feces. During the 2016 field season, PhD student Joseph Taylor and postdoc Amanda Edworthy conducted two sampling rounds at 45 farms. At each farm we installed 6 mist nets and trapped birds throughout the day. We collected 1021 fecal samples from 62 species. The most frequently capture species were white-crowned sparrow (131), American goldfinch (115), song sparrow (114), savannah sparrow (81), American robin (66), house sparrow (62), and house finch (47). Fecal samples were stored in absolute ethanol at -80?C to preserve prey DNA. DNA will be extracted over the winter and sequenced to begin preliminary DNA diet analysis. We also collected feathers which will be analyzed for stable isotopes, as a second method of assessing the trophic interactions of wild birds with local invertebrate communities. Joseph Taylor has expertise in stable isotope analysis and will run these samples over the winter. Objective 3: Assess the birds' risk of spreading pathogens and parasites that endanger food safety and human/livestock health. In addition to fecal samples, we also collected tracheal swabs (to test for pathogens such as avian influenza and West Nile virus), blood smears (for blood parasites), serum (for antibodies indicating past infections), and ectoparasites including ticks and fowl mites. We will use DNA sequences from fecal samples (see above) to screen for pathogenic strains of E. coli, salmonella, listeria, and other human and livestock bacteria, viruses, and parasites. Lab-based assays will be done on these initial samples over the winter. We collected samples during the spring and winter broccoli crops, which corresponded to breeding and migration periods for birds. This contrast will enable us to assess the seasonal differences in pathogen contamination risk on farms, and will also allow us to analyze bird species and individual characteristics influencing pathogen load in wild bird communities.
Publications
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