That, alas, is the rule.

Well, except the bald eagle I saw last week. I was with my sister, and she saw it, too.

Annoyingly, when I saw a peregrine falcon some years back (perched on a lightpost in a K-mart parking lot) my mother assayed that she was unsure. Later, I showed her the picture in Audubon, including the bit about "the only falcon with feathered spurs..." and she admitted that perhaps I had been correct.