Final report for SW16-013
Pest birds cause significant damage to livestock and crop farms across the United States. On dairy farms, pest birds consume and spoil cattle feed while potentially contributing to avian-bovine disease transmission. The objectives of this study were to: 1) conduct a survey of Washington State dairy farmers to determine the economic costs related to pest bird damage; 2) measure the prevalence of specific bacteria in pest bird feces; 3) evaluate how pest bird depredation of cattle feed affects the availability of nutrients for cattle; and 4) provide outreach activities to test and promote efficient, environmentally-sustainable pest bird deterrence methods. A survey of Washington State dairy farmers was conducted during an annual dairy industry meeting. The survey included demographic information about the dairy operation, presence of birds on the dairy, methods of bird deterrence used and the costs associated with these methods, as well as estimated feed losses caused by pest birds. Over the course of three years, we assessed the impact of bird populations on the nutritional composition of cattle feed, presence of bacteria in bird feces, and changes in cattle behavioral patterns. Five dairies were enrolled into the study and visited to collect bird fecal samples, cattle feed samples, and cattle behavioral observations. Bird fecal samples were analyzed for E. coli, Campylobacter, and Salmonella. Fresh and bird-depleted feed samples were analyzed for dry matter, total digestible nutrients (TDN), protein, crude fiber, ash, fat, and net energy. Cow behavioral patterns and the number of birds at the feed bunk were recorded using on-farm cameras. Kestrel nestboxes were installed on a few Washington State dairies to investigate whether attracting native raptors to dairies is an effective pest bird deterrence method. The survey revealed approximately $14 million in bird damage losses for the Washington dairy industry, annually. Farms that reported the presence of more than 10,000 birds per day were more likely to report the presence of Salmonella or Johne’s disease. The prevalence of bacterial populations in bird fecal samples did not differ among farms but Campylobacter jejuni, a strain known for causing abortions in cattle, was discovered in one location. The number of birds observed at the feed bunk and the percentage of nutritional loss in cattle feed differed among pens. Understanding where birds prefer to feed on dairies may improve the effectiveness of bird deterrent management techniques. A variety of bird deterrent methods are available for dairy farmers but, at best, the most commonly used methods are considered only “somewhat effective” by farmers. The use of more sustainable methods, such as attracting native birds of prey to dairies, may be beneficial to dairy cattle well-being as well as dairy farmer economic sustainability.
The objectives of this study were:
- Survey producers. Distribute a survey to all Washington dairy producers to determine perceived rates of feed consumption and destruction and scope of the pest bird issue.
- Outreach. Conduct Extension outreach including educational workshops, field days, producer-to-producer discussions, professional presentations and publications on pest bird issues and control measures.
- Field data collection. Record pest bird counts, bird-induced feed quality changes and pathogen prevalence at the feed bunk, and bird-cow interactions throughout fall-winter seasons at select dairies.
- Perform pilot efficacy trials of native raptor attraction on select dairies.
- Create a web-based tool for producers to help them choose an economically-efficient bird deterrent method, given their site-specific bird damage issues.
The wild bird problem on dairies in the Pacific Northwest (PNW), especially regarding European starlings (Sternus vulgaris), has been compounded with changes in land use and agricultural practices over the past 20-30 years. In other areas of the U.S., the impact of the non-native European starlings on dairies has been linked to significant economic damages (including loss of high-value feed components and subsequent loss of milk production in cows) and disease transmission concerns (including Escherichia coli O157:H7 and Salmonella).
As acreage devoted to blueberry and other fruit crops has dramatically increased in the PNW, dairies are increasingly likely co-located in less than two miles from a fruit crop. This dairy-fruit interface provides an ideal habitat for European starlings to feast on open commodity storage and bunker faces in fall, winter and spring, and then access ripening fruit in summer. Dairy facilities also provide birds with year-round roosting habitats. By assessing bird populations, feed losses, cow behavior and related health factors, this project will result in a comprehensive identification of economic impacts of wild birds not only to producers but to the entire regional economy.
The potential disease vector role of starlings has been documented, although no known studies have evaluated the impact of wild birds on dairy cow behavior and welfare. Video recordings targeting dairy feed bunks will shed light on wild bird-cow interactions that occur when cows are feeding and whether wild bird presence is detrimental to dairy cow welfare. If wild birds are deemed to impose a negative stressor on cows, this factor can be included when determining the need for intervention to control wild bird activity. Documenting feed quality loss (from birds selecting the most nutritious components) and Escherichia coli O157:H7 and Salmonella prevalence (from birds defecating on feed) at the feed bunk, by comparing feed characteristics pre- and post- bird presence, will also lead to a more accurate estimate of bird damage costs. This information will be useful to producers as they consider costs and benefits of implementing wild bird control measures.
The overarching hypothesis is that the presence of wild birds at dairy feed bunks causes dairy cows to consume less feed, increases the number of pathogenic species present at feed bunks, and decreases the amount of nutrients available for cows.
Paper surveys were distributed to Washington State dairy producers at the annual Washington State dairy industry conference. Survey questions included farm demographics, presence of pest birds, prevalence of specific cattle diseases, production parameters, type of pest bird deterrence method used, cost of pest bird deterrence, and estimated losses caused by pest birds. Economic modeling was used to analyze the regional and statewide economic impact of pest bird damage on dairies. Wireless video cameras were installed on five dairies to record dairy cow and wild bird behavior at the feedbunk. These video cameras recorded behavior continuously for at least 24 hours on each farm. The feed bunks of up to four pens at each of the five dairies were observed during feeding times to determine bird depredation patterns. Fresh feed samples were collected to determine the nutritional composition of the feed that cows were meant to consume. Approximately 30 minutes after fresh feed was delivered and wild birds depredated the feed without any disturbances, feed samples were collected for comparison with fresh feed samples. The nutritional components measured in each sample included dry matter, crude fat, crude protein, and carbohydrates. After feed samples were collected, fresh bird fecal matter samples were collected near the feed bunk area. At least five fecal samples were collected from each cow pen. These samples were tested for the presence of Escherichia coli O157:H7, Salmonella, or Campylobacter jejuni. Kestrel nestboxes were installed on a few dairy farms to measure their effectiveness at long-term pest bird deterrence. The presence of kestrels and pest birds on these dairies will be followed for several years.
The survey of Washington State dairy farmers revealed approximately $14 million in bird damage losses for the Washington State dairy industry, annually. Furthermore, farms that reported the presence of more than 10,000 birds per day were more likely to report the presence of Salmonella or Johne’s disease. Our research team also showed that after a mere 30 minutes of depredation, wild birds caused up to a 30% loss of net energy for lactation in cattle feed. E. coli was the most prominent bacteria present in wild bird feces, in which only one sample was positive for Campylobacter jejuni and no samples were positive for Salmonella. The number of cows present at the feed bunk was influenced by the density of wild birds at the feed bunk.
Without intervention, the five-year impact of pest bird depredation of dairy cattle feed will cause a $14.7 million reduction in Washington State’s GDP and a loss of 154 jobs. These losses represent the ripple effects pest bird depredation on dairies have on the regional economy, as calculated by a REMI PI+ model we conducted. The early adopters (20% – 40% of participants) that attended our pest bird deterrence workshops and implemented alternative deterrence methods can, based on our work, anticipate a 52% reduction of feed losses. The expected combined cost savings for these dairies is $1.7 million.
Education and Outreach
During this project, collaborators created factsheets, popular press articles, and newsletter articles about wild bird management strategies on dairies. These articles were often featured in national or international dairy magazines and websites. Other types of outreach included scientific presentations at national meetings, exhibit booths at fairs and meetings, presentations to dairy producers and community members, and on-farm tours. In the last year of this project, we held two workshops/demonstrations. Attendees included dairy producers, crop producers, beef producers, and regional conservation district professionals.
We currently have one scientific journal article in progress and one abstract for a national talk under review.
Education and Outreach Outcomes
- Wild bird migration patterns
- Identification of beneficial wild birds
- Economic impact of wild birds
- Use of sustainable pest bird deterrence methods
Wild bird migration patterns
Identification of beneficial wild birds
Use of sustainable pest bird deterrence methods