Canadian wildfire smoke increases, 40 bird species less frequent in New York after scientists match smoke pollution to observations of 99,000 birds
Smoke from record-breaking wildfires in Canada has not only reduced air quality in parts of the United States in recent years. Wildfires are making it harder to spot many bird species during breeding season in New York state, a new study shows.Researchers at the University at Buffalo say sightings of many bird species have declined as wildfire smoke has increased. They say this doesn’t necessarily mean bird numbers are declining. Instead, the birds may have changed their behavior to make them more difficult for birdwatchers to detect.The findings were published earlier this month in the journal Biodiversity and Conservation, Science X reported. The researchers say the study highlights the often-overlooked effects of wildfire smoke and could help improve how scientists monitor wildlife as climate change increases the frequency and intensity of wildfires.
Smoke and bird watching
The study focuses on the 2021 to 2023 breeding season in New York State. The scientists examined levels of PM2.5, a type of fine particulate matter in the air that is widely used to measure smog pollution.PM2.5 are extremely small particles less than 2.5 microns wide. Because of their small size, they can become suspended in the air and are often produced by wildfires.
Birders record the birds they see and upload their observations.
Researchers found smoke pollution was highest in 2023, Canada’s worst wildfire season on record. During June and July of that year, the smoke traveled hundreds of miles, affecting air quality across New York.Scientists wanted to know whether the smoke had any impact on birds during the most important time of the year, when they breed and raise their young.
Air quality and bird records
To investigate this, the researchers compared air pollution data with bird observations collected through eBird, a citizen science project run by the Cornell Laboratory of Ornithology.In the case of eBird, birders record the birds they see and upload their observations, creating one of the largest bird observation databases in the world.The UB team has since matched PM2.5 levels to nearly 99,000 eBird inspection forms submitted across New York during the 2021 to 2023 breeding seasons.Because birdwatchers have varying levels of experience, the researchers filtered the data and used statistical methods to increase the reliability of the results. In total, they studied 84 species of birds.
Half the species are less common
The researchers found that 40 out of 84 species were less likely to be observed when PM2.5 levels increased. Many of them are migratory forest songbirds, including warblers, thrushes, and vireos.Corresponding author Festus Adegbola, a doctoral student in the Department of Geography at the University at Buffalo, said the findings show a clear link between wildfire smoke and bird observations.
The 2023 wildfires in Canada left much of North America shrouded in dangerous smoke for months.
“Our results suggest a link between wildfire smoke and the likelihood of observing specific bird species,” Science X quoted Adebola as saying.He added, “Wildfire smoke is often underexplored when monitoring biodiversity. Not accounting for air quality can bias species distribution and abundance models.”Researchers believe the smoky environment may have changed the way some birds behave. “Smoke conditions may have changed the behavior of the birds – singing and moving less and spending more time in the dense forest canopy, thus making them harder to detect,” Adebola said.
Some show different patterns
Not all birds react the same way. The study found that 15 species were actually more likely to be observed as PM2.5 levels increased, while the observation frequency of another 29 species did not change significantly.Many of these species are aerial insectivores, which catch insects while flying, or are wetland-associated birds. However, researchers caution that this doesn’t mean wildfire smoke is good for these birds.Co-author Adam Wilson, an associate professor of geography at the University at Buffalo, said the difference may have more to do with where birders choose to stay during smoky weather than to changes in the birds themselves.“These species typically occupy more open environments than forest songbirds, so an increase in their sightings may have more to do with where birders choose to observe during smoke conditions than with the response of the birds themselves,” Wilson said.
