{"fact":"Crows aren't easily fooled!  Even changing hats or wearing a mask upside down doesn't trick crows who have learned to recognize a dangerous face.","context":"Furthermore, after trapping, few crows scolded trappers who wore no mask or who wore a mask that had not been worn during trapping... Scolding of the dangerous mask alone, the dangerous mask with the hat, and the dangerous mask worn upside down (‘inverted’) was similar after trapping.","source":"John M. Marzluff; Jeff Walls; Heather N. Cornell; John C. Withey; David P. Craig, Lasting recognition of threatening people by wild American crows, 10.1016/j.anbehav.2009.12.022","index":23}