Wildfire smoke influences the probability of observing breeding birds in New York State

Wildfires are a common natural disturbance, forging and reshaping ecosystems around the world. With 7.2 million acres of land burned annually in the United States, most research on the impacts of wildfires on birds and other wildlife has focused on how animals respond to the loss and transformation of habitat. However, direct impacts of wildfires extend far beyond the burn perimeter. Smoke from wildfires can be transported hundreds of miles, exposing birds to toxic air across a large geographic area. Yet, research on the impacts of wildfire smoke on wild birds is extremely limited. Quantifying the relationship between wildfire smoke and bird detection is a critical first step in assessing the broader ecological impacts of smoke disturbance. In this study, we assess how fine particulate matter (PM_2.5),  a well-established marker of wildfire smoke and important pollutant, influences the probability of observing birds in New York, USA, during the 2021–2023 wildfire seasons. We used generalized linear mixed models to model bird observations from 98,960 eBird checklists to local measurements using daily mean concentration of PM_2.5. After accounting for habitat, time of day, weather, seasonality, and survey effort, we found that PM_2.5 affected the probability of observing 70% (55 of 84) study species. Of the total 84 study species, 18% (15 species) had a positive interaction with increased PM_2.5concentration, while 48% (40 species) had a negative interaction with PM_2.5 concentration. Our findings demonstrate that wildfire smoke influences the probability of observing birds, likely due to species-specific behavioral responses to smoke pollution. Furthermore, our results support previous research suggesting that wildfire smoke (and air pollution in general) is an important and underexplored component of the detection process; failing to account for the effect air quality may bias models of species distributions and abundance. As climate change continues to escalate global wildfire activity, it is critical to understand how birds will be impacted by more frequent and intense smoke pollution. Our study provides insights into which species may be most vulnerable to acute smoke exposure and guide conservation action in the Pyrocene.