I am speaking from limited experiance, but the last yote I called in walked up to 15 yards. He would stop sniff the ground, proceed, a couple of times he looked directly at my big black remington but kept coming, we did have 6 inches of now 
he eventually walked off b/c he didn't see anything to eat. My theory would be to give him something to look at, so they are less wary of hearing but not seeing.
ps Nothing is more sickening the getting your gun on a coyote at 15 yds and seeing a building in the background.
[This message has been edited by Brennan (edited 02-25-2002).]
