A college student walked into his ornithology class and found five birds with bags over their heads so only their feet showed.

"What's this?" he asked.

"It's an exam," explained the professor. "Your job is to identify each bird by looking at its feet."

"What a stupid test!" complained the student.

"What's your name?" demanded the angered professor.

The student pulled up the legs of his pants and answered, "You tell me."