Birds living in developed areas contend with numerous stressors, including human disturbance
and light, noise, and air pollution. COVID-19 pandemic lockdowns presented a unique
opportunity to disentangle these effects during a period of reduced human activity.
We launched a community science project in spring 2020 to explore drivers of site
use by and detection of common birds in cities under lockdown in the U.S. Pacific
Northwest. Our goals were twofold: (1) consider how intensity of urbanization, canopy
cover, and availability of bird feeders and bird baths influenced avian habitat use;
and (2) quantify how daily changes in weather, air pollution, and human mobility influenced
detection of birds. We analyzed 6,640 surveys from 367 volunteers at 429 monitoring
sites using occupancy models for 46 study species. Neither land cover nor canopy cover
influenced site use by 50% of study species, suggesting that backyard birds may have
used a wider range of habitats during lockdowns. Human mobility affected detection
of 76% of study species, suggesting that birds exhibited species-specific behavioral
responses to day-to-day changes in human activity beginning shortly after initial
lockdown restrictions were implemented. Our study also showcases how existing community
science platforms can be leveraged to support local monitoring efforts.
