Limited changes to mammal diel activity during COVID-19 lockdown in an urban preserve

Animals in urban preserves experience both the security of protected habitats and the persistent anthropogenic disturbances of surrounding human-dominated landscapes. During the COVID-19 pandemic, lockdowns temporarily reduced human activity in urban areas, offering a natural experiment to assess wildlife responses in habitats shaped by both protection and anthropogenic pressures. We therefore used camera traps in an urban preserve in the San Francisco Bay Area, United States, to monitor the diel activity patterns of 6 mammal species before, during, and after the COVID-19 lockdown. While most species made small, hour-level adjustments in activity timing across these 3 periods, black-tailed jackrabbits (Lepus californicus), black-tailed deer (Odocoileus hemionus), bobcats (Lynx rufus), grey foxes (Urocyon cinereoargenteus), and pumas (Puma concolor) did not change their overall diurnality. Jackrabbit and Puma crepuscularity decreased from before to after lockdown, with a corresponding increase in nocturnality for pumas. Only brush rabbits (Sylvilagus bachmani) increased their overall diurnality during lockdown, though this diurnality did not decrease once human activity resumed after lockdown. Overall, these results indicate that short-term changes in human activity may have species-specific and modest effects on mammal diel activity in urban preserves.