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

S1 File). This may reflect additional investments in bird feeding by people who already have a bird feeder. That said, we also observed a weak increase in search intensity for bird feeders. The turn toward bird feeding during Covid lockdowns likely relates to changes in the rela- tive cost of alternative forms of leisure activities, as well as increases in the benefits from con- necting with nature during a stressful time. For example, Qiao et al. [44] found that participation in birdwatching was severely curtailed because of lockdown restrictions across a large number of countries. Most birdwatchers were forced to be hyper-local in their activities, restricted to their backyard or nearby park. While not a testable hypothesis in our setting, an extreme limitation on birdwatching may be a driver of bird feeding. If access to other nature- based activities was also reduced, this would make bird feeding seem relatively more attractive. Moreover, forced time at home during lockdowns may have increased opportunities for peo- ple to notice birds in their gardens and may have piqued their interest in bird feeding. Other possible factors that may have contributed to the increase in bird feeding during the pandemic is the influence of social norms within the local communities. Research has demon- strated that households’ preferences for gardening are often associated with the norms and practices of their neighbors [45]. Thus, it is possible that the proliferation of bird feeders in local neighborhoods may have inspired others to engage in bird feeding. In addition, media

coverage of the activity may also have played a significant role. For instance, the New York Times published an article about the surge in bird feeding at the beginning of the pandemic [46]. This type of media coverage may have raised awareness of and interest in the activity among a wider audience. Fig 1. Google Trends search interest before and after a country’s first Covid-19 lockdown. Notes: This figure shows the estimated change in search intensity for the term "bird feeder," "bird food," and "bird bath" before and after Covid-19 lockdowns relative to the week before the lockdown started. We estimate this change in search intensity based on Eq (1) using data from Google Trends. The search intensity represents people’s indexed search frequency for the three terms related to bird feeding. Each point is the point estimate of the change in bird feeding interest for the period relative to the country’s first lockdown from countries with sufficient search volume for each term. The number of countries that were included for each search term: bird feeder (101), bird food (75), and bird bath (55). A list of countries included in the analysis is available in Table A3 in S1 File Column (1)-(3). A line connects each point estimate. The shaded area is the 95% confidence interval. https://doi.org/10.1371/journal.pone.0287116.g001 PLOS ONE Covid-related surge in global wild bird feeding PLOS ONE | https://doi.org/10.1371/journal.pone.0287116 August 2, 2023 6 / 15