Four geese with Tule radio cages have left their summer breeding grounds near Alaska’s Cook Inlet in late 2020 to head south for the cold. The migration usually takes four days: The birds fly over the Gulf of Alaska, about 60 miles[100 km]from Canada, and land on the island of Vancouver. They stop short to float and rest in the Pacific several times and gather on the Oregon Summer Lake before making their final trip to the Sacramento Valley in California. Last summer, however, the migratory birds encountered heavy smoke near the coasts of British Columbia and Washington — and their behavior became remarkable.
One bird returned north about 50 miles[80 km]north. They were able to fly straight over the Beachie Creek Fire in Oregon and then climb almost four times more often than usual to clear the thick smoke. The fourth bird turned and headed eastward, more than ever, toward Idaho. Tule geese often sleep at night in the swamps, but the four of them stopped at strange places, landing once on the side of Mount Hood.
According to a A study published by the US Geological Survey (USGS) In early October, the migration of these birds in 2020 took twice as much as the migration of 2019 — nine days compared to four days — and flew another 400 miles[470 km]all to avoid smoke. The paper reports that “large fires and thick smoke are a major threat to migratory birds” as wildfires intensify with the onset of autumn migration. There were 68 fires in California, Oregon, and Washington as the geese passed by. Longer migration requires more energy and takes time to heal. As a result, the birds may become infertile and even die.
Cory Overton, a wildlife expert at the USGS Western Ecological Research Center and editor of the paper, observed the birds’ flight in unison in real time, via GPS tracking. “I stared at my computer for days, trying to figure out what the birds were doing because it was so obvious, so obvious, not so strange,” Overton said. All four birds eventually became extinct, however, and landed at their favorite Oregon destination.
Overton and his colleagues believe that this is the first time that scientists have been able to record with certainty how fiery smoke changes a bird’s migration. The birds began to change their behavior when they came in contact with tiny particles of 161 micrograms per cubic meter. Environmental Protection Agency Section for “unhealthy” air in humans. Birds migrating to several western countries were found dead and dying in the same summer and early autumn, among others. Research has found a link between death and toxic gas.
Tule geese, the largest white-fronted geese, are the “most affected geese” in California because of their small population; there are fewer than 10,000 of them. They are at risk of encountering travel obstacles because they follow the same route and stop at the same location each year. Overton and colleagues also followed 12 species of seabirds, which migrate later in the autumn than Tule geese. Smoke billowed from the Pacific Northwest as more and more people passed through the area. But as the Western climate escalates, scientists are concerned that smoke may be preventing more people from moving along the Pacific Flyway. Many shorebirds and songbirds fail to retain the extra energy needed to move around the fire.