Here's the thing though. Greys are also hardwired to be cautious towards pine marten. There are marten in North America, who feed on grey squirrel. So I'm not buying it.
I remember seeing a yourube video one time showing a little experiment with chickens. They stuck one of those birds of prey kites/scarer things up beside the chicken pen, to see if the chickens reacted. They did indeed react, and took to cover.
So, if domesticated chickens are still hardwired to react seeing a silhouette of a bird if prey, then surely a wild grey squirrel is still hardwired to react to the sight o