Changes in avian vocalizations across the northeast United States in response to large-scale wildfire smoke events
Description
Wildfires worldwide are increasing in severity due to anthropogenic change. Beyond their direct effects, enormous smoke plumes produced by wildfires can affect ecosystems far beyond a wildfire’s original range. Although wildfire smoke has been shown to affect animal physiology and movement, its effects on communication in birds have only been tested in a handful of localized studies at small spatial scales. Thus, its broad effects on large-scale patterns of avian communication are relatively unknown. Here, we leverage a large dataset from BirdWeather, a new distributed network of automated bioacoustic monitors, to examine how large smoke events from the 2023 Canadian wildfires affect bird vocalizations across the northeastern United States. We combined and analyzed more than 579,000 bird vocalizations with measurements of local particle pollution (PM2.5) produced by the Canadian wildfires to the north and northwest during the month of June 2023. Increased smoke pollution significantly altered the dynamics of bird vocalizations across the whole northeast United States, particularly affecting the dawn chorus. For diurnal species, vocal activity was reduced during early morning hours, and the onset of daily first vocalizations were significantly delayed. During unhealthy air-quality conditions, daily first vocalizations occurred on average approximately 40 minutes later compared to low-smoke conditions. Conversely, nocturnal species increased vocal activity during early morning hours under conditions of high smoke pollution, although this did not significantly affect the timing of their final calls. These opposing responses suggest that wildfire smoke may alter behavioral timing by modifying ambient light cues normally associated with dawn events. Our results reveal that wildfire smoke can widely restructure community-level patterns of avian communication across broad landscapes. We demonstrate how increasingly severe wildfires can indirectly influence ecologically important behaviors in natural populations and how such phenomena can be studied using emerging advances in citizen science infrastructure and large-scale bioacoustic monitoring.
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Steps to reproduce
Data were collected from the BirdWeather API (https://app.birdweather.com/graphql). Air quality data was collected from the United States Environmental Protection Agency Air Quality System (AQS) database (https://www.epa.gov/outdoor-air-quality-data).