Publication date: Dec 23, 2025
The COVID-19 pandemic provided a natural experiment to test the impacts of human activity on urban-dwelling wildlife. Urban dark-eyed juncos differ in bill shape and size in Los Angeles in comparison to local wildlands. We measured juncos that hatched before, during, and after COVID-19 restrictions at a Los Angeles college campus. Birds that hatched during and soon after COVID-19 restrictions had bills that resembled those of local wildland birds. Yet, bills rapidly returned to pre-COVID-19 morphology in birds hatched in the years following pandemic restrictions. Thus, human activity (and lack thereof) underlies rapid morphological change in an urban bird.
| Concepts | Keywords |
|---|---|
| College | Animals |
| Juncos | anthropause |
| Pandemic | Birds |
| Rapid | COVID-19 |
| Wildlands | COVID-19 |
| dark-eyed junco | |
| Humans | |
| Los Angeles | |
| Pandemics | |
| SARS-CoV-2 | |
| urban ecology | |
| urban evolution |
Semantics
| Type | Source | Name |
|---|---|---|
| disease | MESH | COVID-19 |
Original Article
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