Covid-related surge in global wild bird feeding: Implications for biodiversity and human-nature interaction

noted increased interest in nature-related behaviors among people suddenly restricted in their movements by Covid-19 lockdowns [14]. In several European countries, Roll et al. [15] found a substantial increase in online attention on common bird species but noted an equally marked decline in this interest soon after. Bird feeding, however, may be different, as it enables direct contact with real animals rather than digital images. Because of the intimate nature of the interaction between human and wild animal during wild bird feeding, it can be among the most effective forms of connecting with nature [8]. Backyard feeding helps wild birds survive during critical periods when foraging is difficult or frequent, such as during winter, migration, and when feeding nestlings [16]. Randomized control trials have shown that bird feeding improved the individual health of birds by increas- ing antioxidant levels, reducing stress, and contributing to faster feather growth [17]. On the other hand, garden bird feeding may reshape migration patterns [18], affect ecological com- munities [19–21] and alter bird ranges [22]. Understanding the global extent of bird feeding and its seasonal patterns is vital for understanding changes in bird populations. These connec- tions become even more important given that accelerating changes in climate affect bird popu- lations through lack of food availability [23]. Until recently, it was assumed that the practice of bird feeding was primarily undertaken in the Northern Hemisphere and directed at smaller species that did not migrate [24–26]. While

this may account for the origins of the practice, recent studies have found bird feeding to be far more widespread than was previously thought [1, 27]. The extent and characteristics of bird feeding remain poorly understood, yet the implications for human well-being and conser- vation could be profound [5, 9]. In this study, we explore the extent to which wild bird feeding activity (as measured by Google search index, a valid proxy parameter from Google Trends data) occurs globally. We know from other work that interests in common bird species and bird feeding increased in response to Covid in the U.S. and some European countries during the Covid- 19 pandemic [15, 28]. This study first tests whether this pattern—increased interest in bird feeding in response to Covid-19 lockdowns—holds for all countries, including those in the Southern Hemisphere. If so, Covid-19 lockdowns offer a way to reveal the global extent of bird feeding interest, something that is poorly understood. Bird feeding is best documented in North America, Europe, and Australia, though there are exceptions [25]. If bird feeding is common in other parts of the world, this could impact migration and disease patterns. This study is the first to document the practice of bird feeding at the level of individual countries. In addition, we were interested in whether the practice of bird feeding was related to other factors, including the number of bird species in a country. Previous research has explored the factors that influence interest in bird feeding within a single country, such as socioeconomics

and attitudes toward nature [29, 30]. One study found that the number of bird species within a U.S. state was associated with greater interest in bird feeding in response to Covid-19 lock- downs [28]. The reason for this relationship is unclear. However, if this pattern occurs globally, there may be important implications for avian communities [3]. To further our understanding of global wild bird feeding patterns, we investigated two interdependent questions: (1) was there evidence of increased interest in bird feeding and related topics at a global scale after Covid-19 lockdowns, relative to before; and (2) is species richness correlated with the level of interest in bird feeding? We use species richness as a proxy for the biological diversity of life within an area, e.g., biodiversity, while acknowledging that it is an imperfect measure [31]. Given the relationship between the practice of bird feeding, human mental health, and a variety of pro-environmental attributes, the implications are of great significance for human well-being and biodiversity conservation. PLOS ONE Covid-related surge in global wild bird feeding PLOS ONE | https://doi.org/10.1371/journal.pone.0287116 August 2, 2023 2 / 15