Seven Seattle crows learned one masked face during a 2006 banding. The warning moved through the local flock and across generations before a 2023 walk finally drew silence.
In 2006, University of Washington biologist John Marzluff wore a caveman mask while trapping and banding seven Seattle crows; the birds taught others—including offspring born years later—to scold anyone wearing it, and the warning spread across campus for 17 years before a masked walk in September 2023 finally produced silence.
Natural History