Note to Byron York and Dean: bellwether. It is derived from belle, a bell, and wether, a ram, from the practice of placing a bell around the neck of the leader of a flock. Hence, a leader or portent.
I know it’s considered bad form to correct people’s spelling in blogs but I’m feeling crotchety today.  One of the reasons that English is so darned hard to spell is that it tends to carrry around a word’s etymology along with it long after the pronunciation of the word has changed. However, that provides a clue to the word’s meaning as in this case.
I don’t consider it bad form.
Fixed.