Towards a holistic assessment of the food-safety risks imposed by wild birds

Foodborne disease outbreaks attributed to wildlife have heightened pressure on growers to prevent wildlife from entering their farms (Beretti and Stuart 2007, Gardner et al. 2011, Langholz and Jay-Russell 2013, Baur et al. 2016). Birds are of particular concern as they carry enteric pathogens and move long distances, including between livestock operations and fresh produce fields (Rivadeneira et al. 2016, Navarro-Gonzalez et al. 2019, Smith et al. 2020b). As a result, growers often implement economically and ecologically costly measures to prevent bird intrusion (e.g., bird netting and habitat removal; Beretti and Stuart 2007, Karp et al. 2015, Olimpi et al. 2019). However, despite widespread concern, our knowledge of the risks posed by different species by farming context is still in its infancy. Few species have been studied, with disproportionate focus on species that frequent feedlots, refuse sites, or water bodies rather than crop fields (Smith et al. 2020b). Moreover, no studies have assessed the entire pathogen spillover cycle; that is, the combined likelihood that bird species carry pathogens, enter farms, defecate on crops, and produce feces that enable pathogen survival (Smith et al. 2020b).