Question

Question 18 Not yet answered Marked out of 10.00 Flag question Each spring the buzzards return to Hinkley, Ohio from their wintering grounds in Mexico (this is absolutely true, you can Google it). Remarkably, they make their migration in one continuous flight over about 72 hours, through day and night without a pause. You want to know how they manage to find their way at night and get the clever idea of gluing magnets on the heads of several buzzards to see if they use a magnetic compass. As long as days and nights are clear, they always arrive in Hinkley on schedule, regardless of whether they have magnets or not. However, if nights are cloudy the buzzards with magnets attached fly about randomly and often wind up in places like Pittsburgh or St Louis. What does this suggest about how buzzards might navigate at night?