Penguins in the anthropause: COVID-19 closures drive gentoo penguin movement among breeding colonies

The COVID-19 pandemic caused the Port Lockroy post office, a popular Antarctic tourism destination, to close in 2020, creating a natural experiment to test human impacts on the local gentoo penguins. This study examines the abundance of nesting gentoo penguins before, during, and after the COVID-19 anthropause at different spatial scales centered around the post office. We found that the Port Lockroy population increased 83 % (similar to 450 nesting pairs) from 2018 to 2021, with areas of the island open to pedestrians seeing the greatest gains in the number of nests. Jougla Point, a site just 150 m away from Port Lockroy and located within the same harbor, increased 90 % (similar to 900 nesting pairs) during the closure, while two nearby sites outside the harbor decreased by 60 % and 59 % (similar to 1000 nesting pairs total). We conclude that gentoo penguins immigrated from neighboring sites into the Port Lockroy harbor. This apparent redistribution of nesting gentoo penguins immediately reversed itself when the post office re-opened in 2022. These findings, which are particularly striking given the assumed strong site fidelity of gentoo penguins, suggest that human activity can alter gentoo penguins' choice in nesting location, and that the spatial extent of disturbance is perhaps larger than previously appreciated. We suggest testing the impacts of ship and zodiac traffic on breeding behavior, the cumulative effects of tourism on sets of geographically proximate colonies, and the timing of tourism in relation to nest initiation to inform policies focusing on minimizing disturbances to gentoo penguins as Antarctic tourism resumes.