Thousands of vaux's swifts surprised residents of Salem, Oregon, United States, by forming a huge moving cloud around the tower of a church before disappearing inside a chimney. The phenomenon was recorded on September 6 by resident David P. Craig, a professor at Willamette University, who estimated the presence of more than 4,000 birds. The images circulated on social media and sparked reactions from users who associated the scene with a supposed sign of bad omen.
However, the behavior is well-known among experts and is related to the species' migration, which usually passes through Oregon in large groups between late August and early October, with a peak in September. According to Craig, the swifts use the chimney of the First United Methodist Church of Salem as a resting place during this migration.
Craig's students even counted the birds and explained to visitors the importance of the structure for the species, demonstrating that the phenomenon has a scientific explanation and does not represent any bad omen.
