Their memory for remembering cached objects is generally very good. Caching behavior serves the crow well, increasing survival odds during times when food is scarce. Since ancient times crows have had an uneasy relationship with humans. As potential competitors for our own food, crows are unpopular with farmers and ranchers because the birds eat crops, poultry eggs, and even small livestock. And everyone is familiar with the scarecrows set up to protect cornfields from marauding crows.
People have other gripes with crows.
Messy crow roosts are considered to be a public nuisance. As recently as the 1940s, winter crow roosts were routinely dynamited, poisoned, shot up, or otherwise destroyed-in some cases killing hundreds of thousands of crows. Despite this general unpopularity, however, in 1972 the Migratory Bird Treaty Act was amended to include protection for Corvidae . As a result, today crows may only be hunted according to local laws. Even today, North Americans expend more than five million hunter days a year shooting crows.