Wildfire smoke affects detection of birds in Washington state

Wildfire smoke is likely to have direct health effects on birds, as well
as influence movement, vocalization, and other avian behaviors. These
behavioral changes may affect if and how birds are observed in the wild,
although research on the effects of wildfire smoke on bird behavior is
limited. To evaluate how wildfire smoke affects detection of birds, we
combined data from eBird, an online community science program, with data
from an extensive network of air quality monitors in the state of
Washington over a 4-year period. We assessed how PM2.5, a marker of smoke
pollution, affected the probability of observing 71 bird species during
the wildfire seasons of 2015–2018 using bird observations from 62,908
eBird checklists. After accounting for habitat, weather conditions,
seasonality, and survey effort, we found that PM2.5 affected the
probability of observing 37% of study species. The ambient concentration
of PM2.5 was negatively associated with the probability of
observing 16 species and positively associated with the probability of
observing 10 species, indicating that birds exhibit species-specific
behavioral changes during wildfire smoke events that influence how they
are observed. Our results suggest that wildfire smoke impacts the
presence, availability, and/or perceptibility of birds. Impacts
of smoke pollution on human observers, such as impaired visibility, may
also influence detection of birds. These results provide a
foundation for developing mechanistic hypotheses to explain how birds, and
our studies of them, are impacted by wildfire smoke. Given the projected
increase in large-scale wildfire smoke events under future climate change
scenarios, understanding how birds are affected by wildfire smoke –– and
how air pollution may influence our ability to detect them –– are
important next steps to inform wildlife research and avian conservation.