Impact of the COVID-19 Pandemic on Urban Wildlife: The Case of the Dark-eyed Junco

The COVID-19 pandemic led to unprecedented global lockdowns, resulting in a significant reduction in human activity, a phenomenon termed the "anthropause." This period provided a unique opportunity for scientists to observe the effects of decreased human presence on wildlife. A recent study published in the *Proceedings of the National Academy of Sciences* focused on the dark-eyed junco, a forest-dwelling sparrow that adapted to urban life in Los Angeles, particularly on the campus of the University of California, Los Angeles (U.C.L.A.).

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The dark-eyed juncos in urban environments exhibited notable adaptations, including shorter wings and stubbier beaks, likely influenced by their urban diet. However, during the pandemic lockdown, researchers observed a remarkable reversal in these adaptations. Juncos born on the U.C.L.A. campus during the shutdown displayed beak shapes resembling their wildland counterparts. This change was surprising to researchers, including Pamela Yeh, an evolutionary biologist at U.C.L.A., who noted, “We were really shocked.”

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The study of the juncos is significant as it marks the first documented physical change in a wild animal population due to a reduction in human activity. Other wildlife behaviors during the anthropause included mountain lions approaching urban areas and sea turtles coming closer to shore. Additionally, birds were found to lower the volume of their songs, indicating a broader ecological response to the absence of human noise and activity.

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While the findings highlight the adaptability of wildlife, some ecologists caution against over-interpreting the results. Critics argue that the long-term impacts of urbanization and human encroachment on natural habitats cannot be overlooked. They emphasize that while temporary reductions in human activity may benefit certain species, the underlying threats posed by habitat loss and climate change remain critical challenges for wildlife conservation.

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The research team at U.C.L.A. has expressed hope that their findings will encourage further studies on how urban wildlife can thrive in changing environments. The study underscores the importance of understanding animal adaptability in the face of human-induced changes.

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Future research will likely focus on the long-term effects of the anthropause on urban wildlife populations and their adaptations. Scientists aim to explore whether the changes observed during the pandemic will have lasting implications for species like the dark-eyed junco and others that inhabit urban areas.

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• “We were really shocked,” — Pamela Yeh, Evolutionary Biologist, U.C.L.A.

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