A trait‐based framework for predicting foodborne pathogen risk from wild birds

Abstract

Recent foodborne illness outbreaks have heightened pressures on growers to deter wildlife from farms, jeopardizing conservation efforts. However, it remains unclear which species, particularly birds, pose the greatest risk to food safety. Using >11,000 pathogen tests and 1565 bird surveys covering 139 bird species from across the western United States, we examined the importance of 11 traits in mediating wild bird risk to food safety. We tested whether traits associated with pathogen exposure (e.g., habitat associations, movement, and foraging strategy) and pace‐of‐life (clutch size and generation length) mediated foodborne pathogen prevalence and proclivities to enter farm fields and defecate on crops. Campylobacter spp. were the most prevalent enteric pathogen (8.0%), while Salmonella and Shiga‐toxin producing Escherichia coli (STEC) were rare (0.46% and 0.22% prevalence, respectively). We found that several traits related to pathogen exposure predicted pathogen prevalence. Specifically, Campylobacter and STEC‐associated virulence genes were more often detected in species associated with cattle feedlots and bird feeders, respectively. Campylobacter was also more prevalent in species that consumed plants and had longer generation lengths. We found that species associated with feedlots were more likely to enter fields and defecate on crops. Our results indicated that canopy‐foraging insectivores were less likely to deposit foodborne pathogens on crops, suggesting growers may be able to promote pest‐eating birds and birds of conservation concern (e.g., via nest boxes) without necessarily compromising food safety. As such, promoting insectivorous birds may represent a win‐win‐win for bird conservation, crop production, and food safety. Collectively, our results suggest that separating crop production from livestock farming may be the best way to lower food safety risks from birds. More broadly, our trait‐based framework suggests a path forward for co‐managing wildlife conservation and food safety risks in farmlands by providing a strategy for holistically evaluating the food safety risks of wild animals, including under‐studied species.

Semi‐natural habitat surrounding farms promotes multifunctionality in avian ecosystem services

“…Allowing Barn Swallows to continue to nest on buildings within and adjacent to farms (a common occurrence in our study system) could thus result in positive outcomes for farmers. More generally, installing nest boxes could promote pest‐eating, insectivorous species that carry lower food‐safety risks and infrequently damage crops (Jedlicka et al, 2011; Smith et al, 2021). Importantly, nest boxes can be designed with entrance holes tailored to specific birds; for example, smaller entrance holes sized for swallows and bluebirds may prevent larger birds associated with more disservices (e.g.…”

“…Allowing Barn Swallows to continue to nest on buildings within and adjacent to farms (a common occurrence in our study system) could thus result in positive outcomes for farmers. More generally, installing nest boxes could promote pesteating, insectivorous species that carry lower food-safety risks and infrequently damage crops (Jedlicka et al, 2011;Smith et al, 2021).…”

Complex landscapes stabilize farm bird communities and their expected ecosystem services

“…Our research was conducted with the approval of Washington State University's Institutional Animal Care and Use Committee (ACC protocol ASAF #04760). This manuscript uses point count data (which only requires passive observation of birds) and weights the point count estimates by foodborne pathogen prevalence estimates derived from mist‐netting birds reported previously (Smith, Edworthy, et al., 2020; Smith et al, in press).…”

“…To do so, each bird observed was weighted by its species' estimated Campylobacter spp. prevalence and crop contacts/survey point from Smith et al (in press). Briefly, Smith et al (in press) estimated Campylobacter spp.…”

“…prevalence and crop contacts/survey point from Smith et al (in press). Briefly, Smith et al (in press) estimated Campylobacter spp. prevalence and number of crop contacts/survey point for 139 bird species by examining which of 11 species traits were most predictive of each.…”